Battery cells, batteries and electrical devices

Abstract

The present invention relates to a battery cell, a battery, and an electrical device, wherein the battery cell includes a casing assembly including a casing and a first pole, and a battery core assembly including an active material coating portion and a conductive portion connected to the active material coating portion, the first pole includes a pole body attached to the casing and a first cover plate provided on the pole body, the active material coating portion is housed within the casing, the conductive portion is connected to the pole body via a first weld, the first weld is located at least partially away from the active material coating portion of the pole body, and the first cover plate is used to shield the first weld. The present invention can improve the reliability of the battery cell.

Description

[Technical Field]

[0001] This application relates to the field of battery technology, and more particularly to battery cells, batteries, and electrical devices. [Background technology]

[0002] In recent years, new energy vehicles have made remarkable progress, and in the electric vehicle sector, batteries play an indispensable role as the power source for electric vehicles. Typically, batteries contain multiple battery cells, and during use, these cells are at risk of thermal runaway or short circuits, leading to a decrease in the reliability of the battery cells and hindering improvements in battery performance and lifespan. [Overview of the Initiative] [Means for solving the problem]

[0003] The embodiments of this application provide a battery cell, a battery, and an electrical device that can reduce the probability of thermal runaway and short circuits in the battery cell, improve the reliability of the battery cell, and improve the performance and service life of the battery cell.

[0004] According to a first aspect, an embodiment of the present application provides a battery cell comprising a casing assembly including a casing and a first pole, and a battery core assembly including an active material coated portion and a conductive portion connected to the active material coated portion, wherein the first pole includes a pole body attached to the casing and a first cover plate installed on the pole body, the active material coated portion is housed within the casing, the conductive portion is connected to the pole body via a first weld, the first weld located at least partially away from the active material coated portion of the pole body, and the first cover plate is used to shield the first weld.

[0005] In the above proposed technology, by positioning the first weld on a side that is at least partially separated from the active material coated portion of the pole body, it is possible to reduce the amount of metal residue generated during the welding process that enters the battery cell, to some extent prevent the metal residue from overlapping the positive and negative electrode pieces, and consequently reduce the possibility of an internal short circuit in the battery cell. On the other hand, if the first weld can be separated from the active material coated portion, and the pole body and the conductive portion are welded at a high temperature to form the first weld, the high temperature heat source of the first weld is separated from the active material coated portion, thus reducing the impact of the high temperature generated by welding on the active material coated portion, reducing the probability of damage to the active material coated portion, and improving the reliability of the battery cell. Furthermore, when the battery cell and bus member are welded after the pole body has been welded to the conductive portion inside the casing, the first cover plate shields the first weld, playing a protective role, reducing the impact of the high temperature generated when welding the pole body and bus member on the first weld, and improving the reliability of the connection between the pole body and the conductive portion.

[0006] In some embodiments, the pole post body has a first housing groove, the surface of the first pole post facing the active material coated portion is the inner end face of the pole post, the groove opening of the first housing groove is formed on the inner end face of the pole post, and the first housing groove has a first end wall and a first side wall, the first end wall is located on the side of the first side wall away from the active material coated portion, at least a portion of the conductive portion is housed in the first housing groove, a first welded portion is provided on the first end wall, and a first cover plate fits with the pole post body and covers the first welded portion.

[0007] In the above proposed technology, by providing a first housing groove in the first pole column, the weight of the first pole column can be reduced to some extent, thereby improving the gravimetric energy density of the battery cell and the battery. Furthermore, since the opening of the first housing groove is formed on the inner end face of the pole column, and the inner end face of the pole column is the surface adjacent to the active material coated portion of the first pole column, the first housing groove can be opened facing the direction of the active material coated portion, thereby making it easier for the conductive portion to enter the first housing groove and improving assembly efficiency. In addition, such a first housing groove facilitates processing and improves production efficiency.

[0008] Furthermore, the first housing chamber can be easily processed to have a relatively large volume, allowing it to accommodate more conductive parts. At the same time, since the first housing chamber is open facing the direction of the active material coating area, it can also be used as a buffer and temporary storage structure for the electrolyte, allowing more electrolyte to be contained within the casing. Since battery cells lose electrolyte during the charge and discharge process, more electrolyte can extend the service life of the battery cells. Additionally, since the first housing groove is open facing the direction of the active material coating area, it can also be used as a housing and buffer structure for gases generated inside the battery core assembly, reducing the expansion of the battery cells and improving the reliability and stability of the battery cells.

[0009] Furthermore, since the first housing groove is located inside the first pole column, external foreign matter and impurities are less likely to enter the first housing groove, reducing the impact of external foreign matter and impurities on the cell assembly, thereby improving the stability and reliability of the operation of the battery core assembly, and ultimately improving the stability and reliability of the battery cell and battery. Next, by installing the first weld between the pole column body and the conductive part on the first end wall, the first weld can be further away from the active material coated part when it is inside the first housing groove, further reducing the impact on the active material coated part due to the high temperature generated when welding the pole column body and the conductive part to form the first weld. On the other hand, the first housing groove not only has the function of housing at least a part of the conductive part, but the groove wall of the first housing groove also has the function of realizing an electrical connection with the conductive part, so the structure of the first pole column can be simplified, the processing of the first pole column can be made easier, and the structure of the conductive part can also be simplified, the redundancy of the conductive part can be reduced, and the cost of the conductive part can be reduced. Furthermore, by utilizing the welding between the first end wall and the conductive part, the welding area formed by the first weld can be made relatively large, which not only reduces the difficulty of welding but also improves the reliability and stability of the welding, and ultimately improves the performance of the battery cell.

[0010] Furthermore, since the first welding portion is located within the first receiving groove, not only can it be avoided that the first welding portion protrudes from the outside of the first pole and occupies the space outside the first pole, but also the first cover plate can protect the first welding portion, improving the reliability and stability of the welding between the conductive portion and the first pole.

[0011] In some embodiments, the first end wall has a first recessed groove, and at least a part of the first welding portion is located within the first recessed groove.

[0012] In the above technical solution, the first recessed groove can be used to pre-position and limit the first welding portion. This not only helps to find an appropriate position for welding, which is beneficial for improving production efficiency, but also improves the stability and reliability of the conductive portion, ensuring the stability and reliability of the charging and discharging process of the battery cell. At the same time, by providing the first recessed groove on the first end wall, the thickness of the first end wall can be locally reduced, which is not only beneficial for welding but also for reducing the weight of the first pole and improving the weight energy density of the battery cell.

[0013] In some embodiments, the first pole has a first concave groove. The surface of the first pole on the side away from the active material coating portion is the outer end face of the pole. The groove opening of the first concave groove is formed on the outer end face of the pole, and the first cover plate seals the groove opening of the first concave groove.

[0014] In the above proposed technology, since the first groove is installed on the first pole column, the weight of the first pole column can be further reduced, improving the gravimetric energy density of the battery cells and the battery. On the other hand, since the first groove is located on the outside of the first pole column, that is, it is open to the side that is separated from the inside of the casing of the first pole column, structural components that are electrically connected to each battery cell in the battery can be housed or attached using the first groove, making full use of the space inside the first pole column and improving the space utilization rate and volumetric energy density of the battery. Furthermore, by installing the first groove and having the first cover plate seal the groove opening of the first groove, welding of the first cover plate becomes easier and assembly efficiency is improved.

[0015] Furthermore, since the first pole column has both a first housing groove and a first recessed groove, and the first recessed groove is located on the side of the first housing groove away from the active material coating portion, and the first recessed groove is open facing the opposite direction from the first housing groove, an electrical connection between the conductive portion and the first pole column can be easily achieved by external welding by laser welding the conductive portion and the first end wall through the first recessed groove from the outside of the first pole column, i.e., the side of the first pole column away from the active material coating portion. In other words, with the above structure, external welding between the first pole column and the conductive portion through the first recessed groove becomes easy, the processing and manufacturing of the battery cell becomes easier, and processing and manufacturing costs can be saved.

[0016] In some embodiments, the active material coating portion includes a current collector and an active material layer disposed on the current collector, and the conductive portion includes a tab portion electrically connected to the current collector, the tab portion includes a plurality of tab pieces, the plurality of tab pieces converge at a position close to the current collector to form a first convergence portion, the plurality of tab sheets converge and connect at a position away from the current collector to form a second convergence portion, the first convergence portion connects the second convergence portion and the active material coating portion, the second convergence portion is at least partially housed in a first housing groove, and the second convergence portion is connected to a first end wall via a first weld portion.

[0017] In the above proposed technology, since the tab portion includes a second convergence portion formed by connecting multiple tab sheets, by housing at least a part of the second convergence portion in the first housing groove, the connection between the conductive portion and the first pole column becomes easier, the space of the first pole column can be utilized to the fullest extent, and the volumetric energy density of the battery cell can be improved. When the second convergence portion and the first end wall are electrically connected via a first welded portion, for example, when the second convergence portion is welded (e.g., laser welded) to the first end wall, the configuration of the battery core assembly can be simplified, the number of parts can be reduced, the assembly process can be simplified, and assembly efficiency can be improved.

[0018] In some embodiments, the active material coating portion includes a current collector and an active material layer disposed on the current collector, the conductive portion includes a tab portion and an adapter sheet, the tab portion includes a plurality of tab sheets, the plurality of tab sheets converge at a position close to the current collector to form a first convergence portion, the plurality of tab sheets converge and connect at a position away from the current collector to form a second convergence portion, the first convergence portion connects the second convergence portion and the active material coating portion, the adapter sheet is connected to the second convergence portion, the adapter sheet is at least partially housed in a first housing groove, and the adapter sheet is connected to a first end wall via a first weld portion.

[0019] In the above proposed technology, at least a portion of the adapter sheet is housed within the first housing groove, allowing for more efficient use of the space of the first pole column, further reducing the space occupied by the conductive part within the casing, and improving the volumetric energy density of the battery cell. On the other hand, by using the adapter sheet and the first weld to achieve an indirect electrical connection between the second convergence portion and the first pole column, the adapter sheet can be welded to the first pole column using the portion that avoids the second convergence portion, resulting in a secure weld between the adapter sheet and the first pole column, reducing the risk of welding cracks, further improving the reliability and stability of the battery cell, and simultaneously simplifying the structure of the tab sheet by electrically connecting the first pole column and the tab sheet with the adapter sheet.

[0020] In some embodiments, the first convergence portion is at least partially housed in the first accommodating groove.

[0021] In the above proposed technology, at least a portion of the first convergence portion of the tab portion is housed in the first housing groove, which allows for more efficient use of the space of the first pole column, further reducing the space occupied by the tab portion within the casing, enabling the accommodation of a larger active material coating portion, improving the volumetric energy density of the battery cell, and also allowing for a more appropriate reduction of the redundancy of the tab portion within the casing, further reducing the probability of a short circuit between the tab portion and the active material coating portion.

[0022] In some embodiments, the casing has mounting holes, the first pole post is mounted in the mounting holes, and along the axial direction of the first pole post, the depth H1 of the first housing groove is greater than or equal to the minimum distance H2 from the inner end face of the pole post to the mounting hole.

[0023] In the above proposed technology, the depth H1 of the first housing groove is greater than or equal to the minimum distance H2 from the inner end face of the pole column to the mounting hole in the axial direction of the first pole column. This allows for full utilization of the volume of the first pole column, resulting in a larger depth of the first housing groove, which is advantageous for accommodating more conductive parts. Consequently, the space occupied by conductive parts within the casing can be significantly reduced, further improving the energy density of the battery cell and reducing the redundancy of conductive parts within the casing. At the same time, the large depth of the first housing groove allows for the containment of gases generated by the battery core assembly, ensuring the reliability and stability of the battery cell. It also allows for the containment of more electrolyte, thus guaranteeing the service life of the battery cell.

[0024] In some embodiments, the pole column body has a second housing groove, the surface of the pole column body away from the active material coating is the outer end face of the pole column, the groove opening of the second housing groove is formed on the outer end face of the pole column, the second housing groove has a second end wall adjacent to the active material coating, the first welded part is provided on the second end wall, and the first cover plate fits with the pole column body and seals the groove opening of the second housing groove.

[0025] In the above proposed technology, by installing a second housing groove on the first pole column, the weight of the first pole column can be reduced to some extent, thereby improving the gravimetric energy density of the battery cell and the battery. At the same time, since the opening of the second housing groove is formed on the outer end surface of the pole column, and the outer end surface of the pole column is the surface away from the active material coating portion of the first pole column, the second housing groove can be opened in the direction away from the active material coating portion. As a result, by housing at least a portion of the conductive part in the second housing groove, the conductive part can be easily housed and organized through the opening of the second housing groove, and electrical connection operations between the conductive part and the first pole column can be easily performed through the opening of the second housing groove, thereby reducing the difficulty of battery cell production and improving the production efficiency of battery cells. Here, the first welded portion is provided on the second end wall, meaning that the second housing groove not only has the function of housing at least a part of the conductive portion, but the groove wall of the second housing groove also has the function of realizing welding with the conductive portion. This simplifies the structure of the first pole column and facilitates the processing of the first pole column. Furthermore, the opening direction of the groove opening of the second housing groove facilitates welding between the conductive portion and the groove wall of the second housing groove through the groove opening, reducing the difficulty of welding. Moreover, by realizing a welded connection with the conductive portion using the groove wall of the second housing groove, the welding area formed by the first welded portion between the conductive portion and the first pole column can be made relatively large, improving the reliability and stability of the electrical connection and, consequently, improving the performance of the battery cell.

[0026] Furthermore, since the conductive part is connected to the pole column body via the first weld, welding slag is present in the first weld. By providing the first weld on the second end wall, the welding slag can be kept away from the active material coated area, reducing the amount of welding slag entering the casing. At the same time, the first cover plate shields the first weld, thus protecting it. As a result, the welding slag or a portion of the welding slag that falls onto the first weld is blocked by the first cover plate, further reducing the amount of welding slag entering the casing. By reducing the entry of welding slag into the casing by two times, the risk of short circuits in the battery cell due to the presence of welding slag can be significantly reduced, improving the reliability of the battery cell.

[0027] Furthermore, when the battery cell transmits electricity to the outside, the pole column body needs to be electrically connected to the bus member. In this case, the pole column body and the bus member are welded together. However, since the first cover plate can shield the first welded portion, it is understood that contact between the bus member and the first welded portion can be prevented, or the bus member and the first welded portion can be isolated from each other. This reduces the influence that the first welded portion has on other welded positions on the pole column body.

[0028] In some embodiments, the conductive portion is located on the side of the second end wall facing the active material coating portion.

[0029] In the above proposed technology, the first weld is provided on the side of the second end wall facing the active material coated portion. In this case, the distance between the first weld and the surface located on the outside of the casing of the pole column body is relatively large, thus reducing the influence of the high temperature formed during welding of the pole column body and the bus member on the first weld.

[0030] In some embodiments, the second housing groove communicates with the interior of the casing through the first through-hole, the conductive portion is drilled in the first through-hole and at least partially housed in the second housing groove, and the conductive portion is positioned at least partially away from the active material coated portion of the second end wall.

[0031] In the above proposed technology, since the second housing groove communicates with the inside of the casing through the first through-hole, the second housing groove can also be used as a buffer and temporary storage structure for the electrolyte, allowing more electrolyte to be stored in the casing. Since battery cells lose electrolyte during the charging and discharging process, more electrolyte can extend the service life of the battery cells. Furthermore, since the second housing groove communicates with the inside of the casing through the first through-hole, the second housing groove can also be used as a gas storage and buffer structure for gases generated inside the battery core assembly, reducing the expansion of the battery cells and improving the reliability and stability of the battery cells.

[0032] In some embodiments, the second accommodating groove further has a second side wall, the second side wall is located on the side of the second end wall away from the active material coated portion, and the second side wall and the second end wall surround each other to form a second accommodating groove, the first through hole is opened in the second end wall, the second end wall has a second recessed groove, and at least a portion of the first weld is located within the second recessed groove.

[0033] In the above proposed technology, since the first through-hole is provided in the second end wall, the conductive part can easily enter the second housing groove through the first through-hole, simplifying the structure of the conductive part, reducing redundancy in the conductive part, and lowering the cost of the conductive part. On the other hand, since the portion of the first welded part located within the second recessed groove is fitted tightly to match the shape of the second recessed groove and to achieve electrical connection, the electrical connection position of the conductive part can be pre-positioned and restricted using the second recessed groove, finding an appropriate position to achieve electrical connection is advantageous for improving production efficiency, and the stability and reliability of the electrical connection position can be improved, thereby guaranteeing the reliability and stability of the battery cell charging and discharging operations.

[0034] In some embodiments, the active material coated portion includes a current collector and an active material layer provided on the current collector, and the conductive portion includes a tab portion electrically connected to the current collector, the tab portion includes a plurality of tab sheets, the plurality of tab sheets converge at a position close to the current collector to form a first convergence portion, the plurality of tab sheets converge and connect at a position away from the current collector to form a second convergence portion, the first convergence portion connects the second convergence portion and the active material coated portion, the second convergence portion is at least partially housed in a second housing groove, and the second convergence portion is connected to a second end wall via a first weld portion.

[0035] In the above proposed technology, since the tab portion includes a second convergence portion formed by gathering and connecting multiple tab sheets, it becomes easier to house at least a part of the second convergence portion in the second housing groove, and welding between the conductive portion and the first pole column becomes easier. Furthermore, by housing at least a part of the second convergence portion in the second housing groove, the space of the first pole column can be utilized, reducing the space occupied by the conductive portion within the casing and improving the volumetric energy density of the battery cell.

[0036] In some embodiments, the active material coating portion includes a current collector and an active material layer provided on the current collector, the conductive portion includes a tab portion and an adapter sheet, the tab portion is electrically connected to the current collector, the tab portion includes a plurality of tab sheets, the plurality of tab sheets gather at a position close to the current collector to form a first convergence portion, the plurality of tab sheets gather and connect at a position away from the current collector to form a second convergence portion, the first convergence portion connects the second convergence portion and the active material coating portion, the adapter sheet is connected to the second convergence portion, at least a portion of the adapter sheet is housed in a second housing groove, and the adapter sheet is connected to a second end wall via a first weld portion.

[0037] In some embodiments, at least a portion of the first convergence portion is housed in the second accommodating groove.

[0038] In the above proposed technology, since at least a portion of both the first convergence section and the adapter sheet are housed within the second housing groove, the space of the first pole column can be utilized more effectively, further reducing the space occupied by the conductive part within the casing and further improving the volumetric energy density of the battery cell. In addition, by installing an adapter sheet with a sheet structure, it is convenient for the adapter sheet to enter the second housing groove through the first through-hole.

[0039] In some embodiments, the pole column body is provided with a first housing section, the first housing section has a third housing groove, the surface of the first pole column facing the active material coating section is the inner end face of the pole column, the third housing groove is located on the side of the second housing groove adjacent to the active material coating section, and the groove opening of the third housing groove is formed on the inner end face of the pole column, the third housing groove and the second housing groove are in communication via a first through hole, and at least a portion of the first convergence section is housed in the third housing groove.

[0040] In the above proposed technology, in this case, a portion of the conductive part is located in the third housing groove, and at the same time, the conductive part is also drilled into the first through hole, and the remaining portion of the conductive part is located in the second housing groove. Therefore, the space of the first pole column can be fully utilized, and the space occupied by the conductive part within the casing can be reduced.

[0041] In some embodiments, the casing assembly further includes a second cover plate, which covers the conductive portion located within the first through-hole and the second housing groove.

[0042] In the above proposed technology, at least a portion of the conductive part is located in the second housing groove, the second cover plate covers this portion of the conductive part, and the second cover plate further covers the first through hole. As a result, when the electrolyte enters the second housing groove from the first through hole, the second cover plate prevents the electrolyte from overflowing from the first electrode column in that area, thereby improving the reliability of the battery cell.

[0043] In some embodiments, the casing has mounting holes, the first pole post is mounted in the mounting holes, and along the axial direction of the first pole post, the depth H3 of the second housing groove is greater than or equal to the minimum distance H4 from the outer end face of the pole post to the mounting hole.

[0044] In the above proposed technology, the depth H3 of the second housing groove refers to the maximum depth of the second housing groove along the axial direction of the first pole column. In the axial direction of the first pole column, the depth H3 of the second housing groove is greater than or equal to the minimum distance H4 from the outer end face of the pole column to the mounting hole. This allows for full utilization of the volume of the first pole column, resulting in a larger depth for the second housing groove, which is advantageous for housing more conductive parts. Consequently, the space occupied by conductive parts within the casing can be significantly reduced, further improving the energy density of the battery cell and reducing the redundancy of conductive parts within the casing. Furthermore, the large depth of the second housing groove allows for the containment of gases generated by the battery core assembly, ensuring the reliability and stability of the battery cell. It also allows for the containment of more electrolyte, thus guaranteeing the service life of the battery cell.

[0045] In some embodiments, the pole column body is provided with a first housing section, the first housing section has a fourth housing groove, the surface of the pole column body away from the active material coated section is the outer end surface of the pole column, the groove opening of the fourth housing groove is formed on the outer end surface of the pole column, the fourth housing groove communicates with the inside of the casing through a second through hole, a conductive part is drilled in the second through hole, a first welded part is provided on the hole wall of the second through hole formed in the first housing section, and a first cover plate fits with the pole column body to seal the second through hole.

[0046] In the above proposed technology, by installing a fourth housing groove, welding between the conductive part and the hole wall of the second through-hole can be easily achieved. Furthermore, in some cases, sealing of the second through-hole can be achieved by utilizing the electrical connection between the conductive part and the first pole column. For example, welding between the conductive part and the hole wall of the second through-hole can be performed at the position where the second through-hole is connected to the fourth housing groove, making the operation easier. In addition, by controlling the weld mark, the second through-hole can be sealed with the weld mark and the conductive part, thereby improving the problem of electrolyte leakage from the casing through the second through-hole.

[0047] In some embodiments, the pole body includes a first pole portion and a second pole portion made of different materials and electrically connected, the second pole portion being located on the side of the first pole portion away from the active material coated portion, the first housing portion being installed on the first pole portion or on the first pole portion and the second pole portion, and the first weld portion being provided on the first pole portion.

[0048] In the above proposed technology, the first pole column is made of a composite form with a combination of different materials, and the first pole column located on the inside is housed and fitted into the conductive part for electrical connection, while the second pole column located on the outside is electrically connected to the bus member, etc. This is advantageous for assembling and electrically connecting the first pole column with related parts, reducing mutual interference between the welding position of the first pole column and the conductive part, and between the welding position of the first pole column and the bus member of the battery, thereby improving the reliability and stability of the battery cell.

[0049] In some embodiments, a second housing portion is provided on the first cover plate, the second housing portion has a fifth housing groove, the opening of the fifth housing groove is formed on the end face of the end of the first cover plate facing the active material coated portion, and the fifth housing groove has a third end wall and a third side wall, the third end wall is located on the side of the third side wall away from the active material coated portion, and at least a portion of the first welded portion is housed in the fifth housing groove.

[0050] In the above proposed technology, by installing a fifth housing groove in the first cover plate, the weight of the first pole column can be reduced to some extent, thereby improving the gravimetric energy density of the battery cell and the battery. At the same time, since the groove opening of the fifth housing groove is formed on the end face of the end of the first cover plate facing the active material coating area, and the third end wall is located on the side of the third side wall away from the active material coating area, the fifth housing groove can be opened in the direction away from the active material coating area. Thus, by housing at least a part of the conductive part in the fifth housing groove, the first welded part can be easily housed and arranged through the groove opening of the fifth housing groove, thereby reducing the difficulty of battery cell production and improving the production efficiency of battery cells.

[0051] In some embodiments, the first cover plate is electrically connected to the pole body, or the first cover plate is installed insulated from the pole body.

[0052] In the above proposed technology, the first cover plate can be electrically connected to the pole column body, in which case the first cover plate can also be involved in the electrical connection of the bus member, thereby increasing the area of ​​the weldable region and facilitating welding between the first pole column and the bus member. Furthermore, the first cover plate does not necessarily have to be electrically connected to the pole column body, i.e., the two are insulated from each other, in which case the first cover plate mainly plays the role of protecting the first welded area.

[0053] In some embodiments, the first cover plate includes a first conductive member and a second conductive member made of different materials, the first conductive member being fitted to and electrically connected to the pole body, and the second conductive member being fitted to and electrically connected to the first conductive member.

[0054] In the above proposed technology, by making the first cover plate a composite form and installing the first conductive member in the same material as the first pole column, the electrical connection between the first conductive member and the first pole column is facilitated. For example, the first conductive member and the first pole column can be reliably, stably, and easily connected by welding. Furthermore, because the second conductive member and the first conductive member are made of different materials, the second conductive member can be used to easily connect the first pole column to a bus member made of a different material. For example, the second conductive member and a bus member made of the same material as the second conductive member can be reliably, stably, and easily connected by welding.

[0055] In some embodiments, the first conductive member has a second groove, the second conductive member is fitted into the second groove, and the groove opening of the second groove is formed on the surface of the first conductive member away from the active material coated portion such that the second conductive member is exposed from the groove opening of the second groove.

[0056] In the above proposed technology, by fitting the second conductive member into the first conductive member, the difficulty of assembling the first conductive member and the second conductive member can be reduced, the stability and convenience of the fitting between the first conductive member and the second conductive member can be improved, and the thickness of the first cover plate can be reduced, thereby reducing the space occupied by the first cover plate and improving the space utilization rate of the battery cell. On the other hand, since the second conductive member can be exposed from the surface of the first conductive member away from the second housing groove through the groove opening of the second recess, it is advantageous for realizing an electrical connection between the second conductive member and the bus member outside the first pole post.

[0057] Furthermore, since the groove opening of the second groove is formed on the surface of the first conductive member that is away from the second housing groove, the second groove is open in a direction away from the active material coated portion. As a result, the portion of the first conductive member that defines the groove wall of the second groove is located between the second housing groove and the second conductive member, separating the second housing groove and the second conductive member. This prevents the electrolyte that has entered the second groove from coming into contact with the second conductive member, thereby reducing electrolyte leakage.

[0058] In some embodiments, the first cover plate has stress-relieving grooves, which are located in the outer peripheral region of the first cover plate.

[0059] In the above proposed technology, by installing stress-relieving grooves in the first cover plate, stress generated during the processing of the first cover plate itself and during the electrical connection between the first cover plate and the first pole column can be released, thereby improving related problems such as deformation or damage to the first cover plate due to stress.

[0060] In some embodiments, the battery cell further includes a support located within the casing and adjacent to the first pole column of the active material coating, the support having a relief hole to avoid the conductive portion, which is adapted to extend through this relief hole toward the side of the support away from the active material coating.

[0061] In the above proposed technology, by installing a support on the side of the active material coated area that is close to the first pole column, the support can be used to separate the active material coated area from the casing, thereby improving the reliability of the battery cell. Furthermore, by providing a relief hole in the support, the conductive part can be guided and restrained to penetrate the relief hole and engage with the first pole column. This eliminates the need for the conductive part to detour around the edge of the support to approach the first pole column, thereby simplifying the arrangement of the conductive part, saving material for the conductive part, and reducing costs. In addition, by supporting the conductive part with the support and guiding its engagement with the first pole column, the risk of short-circuit connection between the conductive part and the active material coated area is reduced, further improving the reliability of the battery cell.

[0062] In some embodiments, a first housing section is provided on the pole column body, and a guide section is provided on the support, the guide section surrounding and forming at least a portion of the escape hole, and the guide section extending at least partially to the first housing section.

[0063] In the above proposed technology, the guide portion protrudes from the support and is inserted into the first housing portion, and at least a part of the relief hole is formed within the guide portion. Therefore, when the conductive portion is drilled into the relief hole, at least a part of the conductive portion can be easily housed in the first housing portion. This improves the assembly efficiency of the conductive portion, and at the same time, the installation of the guide portion makes the fitting between the support and the first pole column, and between the support and the conductive portion, more tight and reliable, resulting in a more compact battery cell structure, which is advantageous for improving the energy density of the battery cell.

[0064] In some embodiments, the relief hole includes a first hole step and a second hole step, the second hole step being located on the side of the first hole step adjacent to the active material coated portion, and the cross-sectional area of ​​the second hole step gradually increases along the direction away from the first hole step, the active material coated portion includes a current collector and an active material layer provided on the current collector, the conductive portion includes a tab portion electrically connected to the current collector, the tab portion includes a plurality of tab sheets, the plurality of tab sheets converge at a position adjacent to the current collector to form a first convergence portion, the plurality of tab sheets converge and connect at a position away from the current collector to form a second convergence portion, the first convergence portion connects the second convergence portion and the active material coated portion, at least a portion of the first convergence portion is housed in the second hole step, and the second convergence portion is drilled in the first hole step.

[0065] In the above-described technical proposal, by providing the relief hole to include a second hole step that gradually enlarges facing the active material coated portion, the second hole step can accommodate more of the first convergence portion, improving the compactness of the fitting between the support and the battery core assembly, reducing the overall volume of the battery cell, allowing the battery to accommodate more battery cells, and improving the volumetric energy density of the battery.

[0066] In some embodiments, the support is a single integrated structure, or the support is a separate structure including a removable first support and a second support, with a relief hole defined between the first support and the second support.

[0067] In the above proposed technology, the relief hole is formed in the form of a through-hole that penetrates the support. This makes the integrated support structure easy to process and relatively reliable, and also facilitates assembly of the support and casing assembly, improving assembly efficiency and mating stability. If the support is a separate structure, the support includes a removable first support and a second support, both of which are long plate-like structures, and they may be connected in a removable manner, for example, they can be fitted together by insertion or engagement, making assembly easy. When the relief hole is defined by the mating of the first and second supports and the support and battery core assembly are assembled, it is not necessary to pass the conductive part from one end of the relief hole to the other. Instead, the first and second supports can be combined at the position of the conductive part to sandwich the conductive part, and the relief hole surrounds the conductive part, thus facilitating assembly of the support and battery core assembly and improving assembly efficiency.

[0068] In some embodiments, the casing has a first wall, a mounting hole is formed in the first wall, the pole column body is installed in the mounting hole, the plane on which the cross-section of the mounting hole is located is the projection plane, and the ratio of the projected area of ​​the first weld on the projection plane to the projected area of ​​the first wall on the projection plane, along the direction perpendicular to the projection plane, is in the range of 0.1% to 1%.

[0069] In the above proposed technology, by installing the first welded portion on the projection surface such that the ratio of the projected area of ​​the first weld to the projected area of ​​the first wall on the projection surface is in the range of 0.1% to 1%, the effective current passage area between the conductive portion and the pole column body is increased, the current passage area of ​​the first pole column is increased, and the current passage capability of the first pole column is improved, which is advantageous for increasing the charging speed of the battery cell. At the same time, it is advantageous for improving the thermal diffusion capability of the first pole column to some extent, reducing the current passage temperature of the first pole column, and thus advantageous for reducing the risk of runaway operation of the battery cell.

[0070] In some embodiments, the casing has mounting holes, and the pole column body includes an integrally molded pole column main body, a first position limiting base, and a second position limiting base, the pole column main body being drilled into the mounting holes, the first and second position limiting bases being installed at both ends of the pole column main body along the axial direction of the mounting holes, the first position limiting base being fitted to the outside of the casing in a position-limiting manner, and the second position limiting base being fitted to the inside of the casing in a position-limiting manner, such that the pole column body is riveted to the casing.

[0071] In the above proposed technology, the first position limiting base and the second position limiting base each extend radially outward from the peripheral wall of the mounting hole along the radial direction of the mounting hole. The first position limiting base can restrict the movement of the first pole column relative to the casing in the direction toward the inside of the casing, and the second position limiting base can restrict the movement of the first pole column relative to the casing in the direction toward the outside of the casing. As a result, it becomes easy to securely attach the first pole column to the mounting hole via the first and second position limiting bases, a fixed connection between the first pole column and the casing can be achieved, assembly of the first pole column and the casing is made easier, and there is no need to use any other connection method between the first pole column and the casing. This facilitates a secure connection between the first pole column and the casing, which is advantageous for simplifying the structure of the casing assembly and the assembly process of the casing assembly.

[0072] Furthermore, since the pole column body, the first position limiting base, and the second position limiting base are integrally molded, material savings can be made, reducing costs. At the same time, it is convenient for ensuring the strength of the first pole column. When the first pole column is fitted to the casing, it will not easily come off the casing due to vibration or external pulling during the charging and discharging process of the battery cell. It will also be less prone to cracking or damage due to vibration or external pulling, improving the stability and reliability of the casing assembly, and thereby improving the stability and reliability of the battery cell.

[0073] In some embodiments, the battery cell further includes an outer insulating member wrapped around the outside of the casing. In the above technical proposals, the outer insulating member serves an insulating role, separating the casing from external components and providing insulation. For example, the outer insulating member is a blue film.

[0074] In some embodiments, the casing has a first wall, the first wall has mounting holes, the pole body is installed in the mounting holes, the battery cell further includes a patch covering the outside of the first wall, the outer insulating member includes an outer insulating film which is an integrated diaphragm, the outer insulating film has a connection portion which extends to the outside of the first wall and connects to the patch.

[0075] In the above proposed technology, in order to facilitate the connection and installation of the connector and the patch, the connector can be overlapped with the patch along the axial direction of the mounting hole. In this case, the outer insulating film and the patch can separate at least the first pole post of the first wall from the casing, improving the insulation reliability between the first pole post and the casing, thereby improving the reliability of the battery cell's operation. For example, the connector can extend in an annular manner along the outer circumference of the first wall, and the outer insulating member can be wrapped around all other walls of the casing other than the first wall. The connector can be provided between the patch and the first wall, and the patch can play a certain protective role against the connection between the connector and the patch.

[0076] In some embodiments, the minimum distance between the edge of the outer insulating film and the first pole is 3 mm or more. In this technical proposal, the creepage distance between the first pole and the casing may also be 3 mm or more, which is advantageous for improving the dielectric strength between the first pole and the casing.

[0077] According to a second aspect, an embodiment of the present application provides a battery including the aforementioned battery cell.

[0078] In the above proposed technology, the first weld of the battery cell is located at least partially away from the active material coated portion of the pole body, thereby separating the first weld from the active material coated portion. When the pole body and the conductive portion are welded at high temperature to form the first weld, the first weld, which is a high-temperature heat source, is separated from the active material coated portion. This reduces the impact of the high temperature generated by welding on the active material coated portion, lowers the probability of damage to the active material coated portion, and improves the reliability of the battery cell. Furthermore, after the pole body is welded to the conductive portion inside the casing, when the battery cell and the bus member are welded, the first cover plate shields the first weld, providing protection. This reduces the impact of the high temperature generated when welding the pole body and the bus member on the first weld, improving the reliability of the first weld between the pole body and the conductive portion. As can be seen from the above, the reliability of the battery can be improved by installing a battery including the above battery cell.

[0079] In some embodiments, the battery further comprises a plurality of battery cells and a bus member, the bus member being electrically connected to the first poles of at least two battery cells, the first poles of the same polarity of each battery cell being electrically connected to the bus member via a second weld, the second weld being formed in a first cover plate, the casing of which includes a first wall, the first wall having mounting holes, the pole body being installed in the mounting holes, and in the cross-section of the mounting hole, the orthogonal projected area of ​​the second weld being 0.2% or more of the orthogonal projected area of ​​the first wall.

[0080] In the above proposed technology, by setting the orthographic area of ​​the second weld between the bus member and the corresponding first pole column in the cross-section of the mounting hole to 0.2% or more of the orthographic area of ​​the first wall, the effective current passage area between the bus member and the corresponding first pole column is set to 0.2% or more of the orthographic area of ​​the first wall, thereby increasing the effective current passage area between the bus member and the first pole column, increasing the current passage area of ​​the first pole column, improving the current passage capability of the first pole column, which is advantageous for increasing the charging speed of the battery cell. At the same time, it is advantageous for improving the heat diffusion capability of the first pole column to some extent, reducing the current passage temperature of the first pole column, which is advantageous for reducing the risk of runaway battery cell operation.

[0081] In some embodiments, the portion of the bus member that overlaps with the pole column body of the same polarity along a direction perpendicular to the cross-section of the mounting hole is the weldable region of the bus member, and the orthogonal projected area of ​​the second weld in the cross-section of the mounting hole is 0.2 or more of the area of ​​the weldable region of the bus member.

[0082] In the above proposed technology, the weldable area of ​​the bus member overlaps with the pole column body in a direction perpendicular to the projection plane; in other words, along the direction perpendicular to the projection plane, the projection of the weldable area of ​​the bus member in the cross-section of the mounting hole at least partially overlaps with the projection of the pole column body in the cross-section of the mounting hole. Thus, the weldable area of ​​the bus member can be understood as the area weldable to the pole column body provided by the bus member, and in this case, the area of ​​the weldable area is necessarily greater than or equal to the orthographic projection area of ​​the second weld on the projection plane. Furthermore, assuming that the current-passing capacity and heat-diffusing capacity of the pole column body are appropriately improved, the projection area of ​​the second weld on the projection plane has an appropriate ratio in order to facilitate welding between the bus member and the pole column body.

[0083] In some embodiments, the portion of the bus member that overlaps with a first pole column of the same polarity along a direction perpendicular to the cross-section of the mounting hole is the weldable region of the bus member, and the area of ​​the weldable region of the bus member is 20% or more of the orthographic area of ​​the bus member in the cross-section of the mounting hole.

[0084] In the above proposed technology, the weldable area of ​​the bus member overlaps with the first pole post of the same polarity in a direction perpendicular to the cross-section of the mounting hole; in other words, along the direction perpendicular to the cross-section of the mounting hole, the orthographic projection of the weldable area of ​​the bus member in the cross-section of the mounting hole at least partially overlaps with the orthographic projection of the first pole post of the same polarity in the cross-section of the mounting hole. Thus, the weldable area of ​​the bus member can be understood as the area weldable to the pole post of the first bus member provided by the bus member, in which case the area of ​​the weldable area of ​​the bus member is necessarily greater than or equal to the orthographic projection area of ​​the second weld in the cross-section of the mounting hole. The area of ​​the weldable area of ​​the bus member is 20% or more of the orthographic projection area of ​​the bus member in the cross-section of the mounting hole. This allows the bus member to provide a weldable area sufficient to lay the foundation for improving the current passage capability and heat diffusion capability of the first pole post.

[0085] In some embodiments, the area of ​​the weldable region of the bus member is 50% or less of the orthographic projection area of ​​the bus member in the cross-section of the mounting hole.

[0086] In the above proposed technology, setting the area of ​​the weldable region of the bus member to 50% or more of the orthographic projection area of ​​the bus member in the cross-section of the mounting hole is advantageous in further balancing the current passing capacity of the first pole column with the convenience of welding work.

[0087] According to a third aspect, an embodiment of the present application provides an electrical device including the aforementioned battery.

[0088] To further clarify the technical concept of the embodiments of this application, the drawings used in the embodiments are briefly introduced below. However, it should be understood that these drawings only show some embodiments of this application and should therefore not be considered limiting in scope. Those skilled in the art can obtain other relevant drawings based on these drawings without any creative work. [Brief explanation of the drawing]

[0089] [Figure 1] This is a schematic diagram of the structure of a vehicle provided by some embodiments of the present application. [Figure 2] This is an exploded view of the structure of a battery provided by some embodiments of the present application. [Figure 3] This is a schematic diagram of the structure of a battery cell provided by some embodiments of the present application. [Figure 4] This is an orthographic projection of a battery cell provided by some embodiments of the present application. [Figure 5] This is a cross-sectional view along the line A-A in Figure 4. [Figure 6] This is a schematic diagram of the structure of a battery cell provided by some embodiments of the present application. [Figure 7] This is an assembly diagram of a second pole, a battery core assembly, and a casing, provided in some embodiments of the present application. [Figure 8] This is a schematic diagram of a local cross-section of a battery cell provided by some embodiments of the present application. [Figure 9] This is a schematic diagram of a local cross-section of a battery cell provided by some embodiments of the present application. [Figure 10] This is a schematic diagram of a local cross-section of a battery cell provided by some embodiments of the present application. [Figure 11] This is a schematic diagram of a local cross-section of a battery core assembly provided by some embodiments of the present application. [Figure 12] This is a convergence diagram of multiple types of tabs for a battery core assembly provided by some embodiments of the present application. [Figure 13] This is a schematic diagram of a local cross-section of a battery cell provided by some embodiments of the present application. [Figure 14] This is a schematic diagram of a local cross-section of a battery cell provided by some embodiments of the present application. [Figure 15] This is a schematic diagram of a local cross-section of a battery cell provided by some embodiments of the present application. [Figure 16] This is a schematic diagram of a local cross-section of a battery cell provided by some embodiments of the present application. [Figure 17] This is a schematic diagram of a local cross-section of a battery cell provided by some embodiments of the present application. [Figure 18]This is a close-up view of area B in Figure 3. [Figure 19] These are orthographic projections of several types of first pole columns provided by some embodiments of the present application. [Figure 20] This is a schematic diagram of a local cross-section of a battery cell provided by some embodiments of the present application. [Figure 21] This is a schematic diagram of a local cross-section of a battery cell provided by some embodiments of the present application. [Figure 22] This is a schematic diagram of a local cross-section of a battery cell provided by some embodiments of the present application. [Figure 23] This is an exploded view of the structure of a battery cell provided by some embodiments of the present application. [Figure 24] This is a schematic diagram of a local cross-section of a casing assembly provided by some embodiments of the present application. [Figure 25] Figure 24 is an exploded view of the casing assembly shown. [Figure 26] Figure 25 is an exploded view of the structure of the first cover plate. [Figure 27] This is a schematic diagram of a local cross-section of a battery cell provided by some embodiments of the present application. [Figure 28] Figure 27 is an exploded view of the structure of a battery cell. [Figure 29] This is a schematic diagram of a local cross-section of a battery cell provided by some embodiments of the present application. [Figure 30] This is a schematic diagram of a local cross-section of a battery cell provided by some embodiments of the present application. [Figure 31] This is a schematic diagram of a local cross-section of a battery cell provided by some embodiments of the present application. [Figure 32] This is a schematic diagram of a local cross-section of a battery cell provided by some embodiments of the present application. [Figure 33] This is a schematic diagram of a local cross-section of a battery cell provided by some embodiments of the present application. [Figure 34] This is a schematic diagram of the mating of a battery core assembly and support provided in some embodiments of the present application. [Figure 35]This is a cross-sectional view along the line C-C in Figure 34. [Figure 36] This is a schematic diagram of the structure of an integrated support provided by several embodiments of the present application. [Figure 37] This is a schematic diagram of the structure of a separate support provided by several embodiments of the present application. [Figure 38] This is a schematic local cross-sectional view of a battery core assembly and support provided in some embodiments of the present application. [Figure 39] This is an exploded view of the structure of a battery core assembly, support, and casing assembly provided by some embodiments of the present application. [Figure 40] This is an exploded view of the structure of the first pole column, casing, and seal pad provided by several embodiments of the present application. [Figure 41] Figure 40 is an assembly diagram of the first pole column, casing, and seal pad. [Figure 42] This is a schematic diagram of the structure of the first pole column provided by several embodiments of the present application. [Figure 43] This is an assembly diagram of a first pole post, casing, and seal pad provided by several embodiments of the present application. [Figure 44] Figure 43 is an exploded view of the structure of the first pole column. [Figure 45] This is an orthographic projection of a battery cell provided by some embodiments of the present application. [Figure 46] This is an orthographic projection of a battery cell provided by some embodiments of the present application. [Figure 47] Figure 46 is a cross-sectional view along the DD line. [Figure 48] This is a schematic cross-sectional view of a casing assembly provided by some embodiments of the present application. [Figure 49] This is a schematic cross-sectional view of a casing assembly provided by some embodiments of the present application. [Figure 50] This is an orthographic projection of a battery cell provided by some embodiments of the present application. [Figure 51] Figure 50 is a cross-sectional view along the EE line. [Figure 52] This is a schematic diagram of a local cross-section of a battery cell provided by some embodiments of the present application. [Figure 53] This is a schematic diagram of the structure of a casing cover provided by some embodiments of the present application. [Figure 54] This is a local schematic diagram 1 of a battery cell provided by some embodiments of the present application. [Figure 55] This is a schematic local view 2 of a battery cell provided by some embodiments of the present invention. [Figure 56] This is a schematic diagram of a battery cell provided by one embodiment of the present invention. [Figure 57] This is a schematic diagram of the electrical connection between a battery cell and a bus component provided by one embodiment of the present invention. [Figure 58] This is a schematic diagram of the electrical connection between the bus member and the pole provided in one embodiment of the present invention. [Figure 59] Figure 56 is a schematic diagram showing the connection between the first polarity pole and the conductive part of the battery cell. [Figure 60] This is a schematic diagram of the mounting of the first polar pole provided by one embodiment of the present application. [Figure 61] This is a schematic diagram of the mounting of the first polar pole provided by one embodiment of the present application. [Figure 62] This is a schematic diagram of the mounting of the first polar pole provided by one embodiment of the present application. [Figure 63] This is a schematic diagram of the mounting of the first polar pole provided by one embodiment of the present application. [Figure 64] This is a schematic diagram of the mounting of the first polar pole provided by one embodiment of the present application. [Figure 65] This is a schematic diagram of the mounting of the first polar pole provided by one embodiment of the present application. [Figure 66] This is a schematic diagram of a battery core assembly provided according to one embodiment of the present invention. [Figure 67] This is a schematic diagram showing the arrangement of the first polar pole column and the second polar pole column provided in one embodiment of the present application. [Figure 68]This is a schematic diagram showing the arrangement of the first polar pole column and the second polar pole column provided in one embodiment of the present application. [Figure 69] This is a schematic diagram showing the arrangement of the first polar pole column and the second polar pole column provided in one embodiment of the present application. [Figure 70] This is a schematic diagram showing the arrangement of the first polar pole column and the second polar pole column provided in one embodiment of the present application. [Figure 71] This is a schematic diagram showing the arrangement of the first polar pole column and the second polar pole column provided in one embodiment of the present application. [Figure 72] This is a schematic diagram showing the arrangement of the first polar pole column and the second polar pole column provided in one embodiment of the present application. [Figure 73] This is a schematic diagram of the mounting of the first polar pole provided by one embodiment of the present application. [Figure 74] This is a schematic diagram of a battery cell provided by one embodiment of the present invention. [Figure 75] Figure 74 is a schematic diagram of the connection between the outer insulating member and the patch. [Modes for carrying out the invention]

[0090] To further clarify the purpose, technical proposal and advantages of the embodiments of this application, the technical proposal of the embodiments of this application will be clearly described below in conjunction with the drawings of the embodiments of this application. However, it should be clear that the embodiments described are only a selection of embodiments of this application, not all embodiments. All other embodiments that a person skilled in the art could obtain without creative work based on the embodiments of this application also fall within the scope of the claims of this application.

[0091] Unless otherwise defined, all technical and scientific terms used in this Application have the same meaning as those generally understood by those skilled in the art relating to the Application. Terms used in the Specification of this Application are solely for the purpose of describing specific embodiments and are not intended to limit this Application. The terms “including” and “having,” and any variations thereof, in the description of the Specification, Claims, and the Drawings, are intended to cover non-exclusive inclusion. Terms such as “first,” “second,” etc., in the Specification, Claims, or the Drawings are used to distinguish different subjects and are not intended to indicate a particular order or priority.

[0092] In this application, where the term "Examples" is used, it means that the specific features, structures, or characteristics described in conjunction with the Examples are included in at least one of the Examples of this application. The occurrence of the term in each position of the specification does not necessarily refer to the same Example, nor do they represent mutually exclusive, independent, or substitutable Examples.

[0093] In this description, unless otherwise specified or limited, the terms “attachment,” “connection,” “joining,” and “attaching” should be understood broadly to mean, for example, a fixed connection, a removable connection, an integral connection, a direct connection, an indirect connection via an intermediate medium, or internal communication between two elements. A person skilled in the art may understand the specific meaning of these terms in this application depending on the specific circumstances.

[0094] In this application, the term "and / or" merely describes a related relationship that explains the related objects, indicating that three types of relationships are possible. For example, A and / or B can represent three cases: A existing alone, A and B existing simultaneously, and B existing alone. In addition, the symbol " / " in this application generally indicates that the preceding and following related objects are in an "or" relationship.

[0095] In the embodiments of this application, the same drawing symbols represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the dimensions such as thickness, length, and width of various components in the embodiments of this application shown in the drawings, as well as the overall dimensions such as thickness, length, and width of the integrating device, are merely illustrative and do not constitute any limitation on this application.

[0096] In this application, "multiple" refers to two or more (including two).

[0097] In this application, the battery cell may include lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries, or magnesium-ion batteries, and the embodiments of this application are not limited to these. The battery cell may be cylindrical, flattened, rectangular, or have other shapes, and the embodiments of this application are not limited to these. Battery cells are generally classified into three types according to the encapsulation method: cylindrical battery cells, prismatic battery cells, and soft-pack battery cells, but the embodiments of this application are not limited to these either.

[0098] The batteries referred to in the embodiments of this application refer to a single physical module containing one or more battery cells to provide higher voltage and capacity. For example, the batteries referred to in this application may be battery modules or battery packs. Battery modules generally contain multiple battery cells. Battery packs generally include a case for enclosing one or more battery cells or one or more battery modules. The case can prevent liquids or other foreign matter from affecting the charging or discharging of the battery cells.

[0099] Exemplary, a battery cell typically includes a casing, a battery core assembly, and an electrolyte, the casing being used to house the battery core assembly and the electrolyte, and the casing being provided with at least one positive electrode column and at least one negative electrode column. The battery core assembly includes one or more electrode assemblies, the electrode assemblies being formed by laminating or winding positive electrode pieces, negative electrode pieces, and separator films.

[0100] In this configuration, the positive electrode section generally includes a positive electrode current collector and a positive electrode active material layer. The positive electrode active material layer is applied directly or indirectly to the positive electrode current collector, and the positive electrode current collector not coated with the positive electrode active material layer protrudes from the positive electrode current collector coated with the positive electrode active material layer. The positive electrode current collector not coated with the positive electrode active material layer forms a positive electrode tab sheet, and multiple positive electrode tab sheets are stacked and electrically connected to a positive electrode column. Exemplarily, multiple stacked positive electrode tab sheets can be directly welded to a positive electrode column to form an electrical connection, or the battery core assembly may include a positive electrode adapter sheet, in which multiple stacked positive electrode tab sheets are welded to one end of the positive electrode adapter sheet, and the other end of the positive electrode adapter sheet is welded to a positive electrode column, thereby electrically connecting the positive electrode tab sheet and the positive electrode column.

[0101] The negative electrode piece generally includes a negative electrode current collector and a negative electrode active material layer, the negative electrode active material layer being directly or indirectly coated onto the negative electrode current collector, a negative electrode current collector without the negative electrode active material layer protruding from the negative electrode current collector with the negative electrode active material layer, and a positive electrode current collector without the negative electrode active material layer being used as a negative electrode tab sheet, with multiple negative electrode tab sheets laminated together and electrically connected to the negative electrode column. Exemplarily, multiple laminated negative electrode tab sheets can be directly welded to the negative electrode column to form an electrical connection, or the battery core assembly may include a negative electrode adapter sheet, with multiple laminated negative electrode tab sheets welded to one end of the negative electrode adapter sheet and the other end of the negative electrode adapter sheet welded to the negative electrode column, thereby electrically connecting the negative electrode tab sheet and the negative electrode column. The material of the separator film is not particularly limited and may be, for example, polypropylene or polyethylene.

[0102] At the same time, a battery cell functions primarily by relying on the movement of metal ions between the positive and negative electrode pieces. Taking a lithium-ion battery as an example, the material of the positive electrode current collector may be aluminum, the material of the positive electrode active material layer may be lithium cobalt oxide, lithium iron phosphate, lithium ternary, or lithium manganese oxide, the material of the negative electrode current collector may be copper, and the material of the negative electrode active material layer may be carbon or silicon. During the charging and discharging process, Li+ ions repeatedly insert and remove between the two electrodes. During charging, Li+ ions are removed from the positive electrode and inserted into the negative electrode via the electrolyte, making the negative electrode lithium-rich, and the reverse occurs during discharging.

[0103] In recent years, new energy vehicles have made remarkable progress, and in the electric vehicle sector, power batteries play an irreplaceable and crucial role as the power source for electric vehicles. A battery consists of a case and multiple battery cells housed within the case. As a core component of new energy vehicles, batteries are subject to relatively high demands in terms of both safety and cycle life.

[0104] In manufacturing battery cells related to the relevant technology, an active material layer is applied to a current collector and then cut to obtain an electrode piece consisting of a current collector with the active material layer applied (referred to as the active material coated portion) and a current collector without the active material layer applied (referred to as a tab sheet). Subsequently, the positive electrode piece, negative electrode piece, and separator are sequentially stacked or wound to obtain an electrode assembly. In the electrode assembly, multiple tab sheets are stacked to form tab portions, the tab portions themselves form conductive portions, or the tab portions are connected to an adapter sheet to form conductive portions, and the active material coated portion and the conductive portions form a battery core assembly. Electrode columns are installed in the casing of the battery cell, and the surface of the electrode column facing the active material coated portion is the inner end face of the electrode column. In the relevant technology, the conductive portion is generally welded to the inner end face of the electrode column.

[0105] The inventors discovered that in the assembly process of a battery cell, the tabs are first welded to the inner end faces of the electrode posts. However, because the first weld is located on the inner end face of the electrode post and is close to the inside of the battery cell, it is difficult to completely remove metal residue during the welding process. If the remaining metal residue falls onto the active material coating and overlaps with the opposite polarity electrode piece, it can cause an internal short circuit in the battery cell, reducing the reliability of the battery cell. Furthermore, high temperatures are generated during the welding process between the tabs and electrode posts. The high temperatures when the tabs form weld marks burn the active material coating inside the casing, causing the active material coating to be lost, which in turn reduces the performance of the battery cell and is detrimental to extending its service life. On the other hand, in the process of forming a battery from battery cells, the electrode posts of one battery cell need to be welded to the electrode posts of another battery cell via a bus member. High temperatures are generated during the welding process. In this case, the high temperatures generated during the welding of the electrode post to the external bus member affect the weld between the tab and the electrode post, causing the weld to remelt and loosen easily, which in turn reduces the performance of the battery cell.

[0106] Based on the above considerations, in order to solve the problems of internal short circuits caused by metal residue generated during welding, damage to the active material coated area due to high temperatures generated during tab welding, and the impact on the welded area between the tab and the electrode post when welding the electrode post and bus member of the battery cell during the process of assembling the battery cell into a battery, the inventors have diligently researched and designed a battery cell including a casing assembly and a battery core assembly. The casing assembly includes a casing and a first electrode post, the first electrode post including an electrode post body attached to the casing and a first cover plate installed on the electrode post body. The battery core assembly includes an active material coated area and a conductive part connected to the active material coated area, the active material coated area is housed in the casing, and the conductive part is connected to the electrode post body via a first weld. By positioning the first weld at least partially away from the active material coated area of ​​the electrode post body, it is possible to reduce the amount of metal residue generated during the welding process that enters the battery cell, to some extent prevent the metal residue from overlapping the positive and negative electrode pieces, and consequently reduce the possibility of internal short circuits in the battery cell. By separating the first weld from the active material coated area, the influence of high temperatures generated by welding on the active material coated area can be reduced, thereby lowering the probability of damage to the active material coated area. Furthermore, after the pole column body is welded to the conductive part inside the casing, when the battery cell and bus member are welded, the first cover plate shields the first weld, providing protection and reducing the influence of high temperatures generated when welding the pole column body and bus member on the first weld, thereby improving the reliability of the first weld between the pole column body and the conductive part.

[0107] The batteries disclosed in the embodiments of this application can be used in, but are not limited to, electrical devices such as vehicles, ships, and aircraft. A power supply system for such electrical devices can be constructed using the batteries disclosed in this application.

[0108] Embodiments of the present invention provide an electrical device that uses a battery as a power source, which may be, but is not limited to, a mobile phone, tablet, laptop computer, electric toy, power tool, electric scooter, electric vehicle, ship, or aerospace vehicle. Among these, electric toys may include stationary or mobile electric toys, such as game consoles, electric vehicle toys, electric ship toys, and electric airplane toys, while aerospace vehicles include airplanes, rockets, space shuttles, and spacecraft.

[0109] To facilitate explanation, the following embodiments will use a vehicle 1000, which is an electrical device, as an example to describe in detail the structure of the electrical device 1000, battery 100, and battery cell 10 of the present invention.

[0110] Referring to Figure 1, which is a schematic diagram of the structure of a vehicle 1000 provided by some embodiments of the present application, the vehicle 1000 may be a fuel-powered vehicle, a gas vehicle, or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle, or a range extender vehicle, etc. A battery 100 is installed inside the vehicle 1000, and the battery 100 may be installed in the bottom, head, or tail of the vehicle 1000. The battery 100 is used to supply power to the vehicle 1000, and for example, the battery 100 can function as the operating power source for the vehicle 1000. The vehicle 1000 may further include a controller 200 and a motor 300, the controller 200 controlling the battery 100 to supply power to the motor 300, and is used, for example, to meet the operating power demands of the vehicle 1000 during starting, navigation, and driving.

[0111] In some embodiments of the present invention, the battery 100 can be used not only as an operating power source for the vehicle 1000, but also as a driving power source for the vehicle 1000, providing driving force to the vehicle 1000 in place of or in part of fuel or natural gas.

[0112] Referring to Figure 2, which is an exploded view of the structure of a battery 100 provided in some embodiments of the present application, the battery 100 comprises a case 20 and a plurality of battery cells 10, the battery cells 10 housed in the case 20. The case 20 provides assembly space for the battery cells 10, and the case 20 can employ a variety of structures. In some embodiments, the housing case 20 may include a first case body 201 and a second case body 202, the first case body 201 and the second case body 202 covering each other, and the first case body 201 and the second case body 202 jointly define assembly space for housing the battery cells 10. The second case body 202 may be a hollow structure with one end open, and the first case body 201 may be a plate-like structure. The first case body 201 covers the open side of the second case body 202 so that the first case body 201 and the second case body 202 jointly define an assembly space. Both the first case body 201 and the second case body 202 may be hollow structures with one end open, and the open side of the first case body 201 covers the open side of the second case body 202. Of course, the shape of the case 20 formed by the first case body 201 and the second case body 202 may be various shapes such as cylindrical or rectangular parallelepiped.

[0113] In the battery 100, multiple battery cells 10 can be connected in series, in parallel, or in series-parallel connection, where series-parallel connection refers to the connection of multiple battery cells 10 in both series and parallel. Multiple battery cells 10 can be directly connected in series, in parallel, or in series-parallel connection, and the entire assembly of multiple battery cells 10 can be housed in the case 20. Of course, the battery 100 can also first form a battery module by connecting multiple battery cells 10 in series, in parallel, or in series-parallel connection, and then form the whole assembly by further connecting multiple battery modules in series, in parallel, or in series-parallel connection, and then housed in the case 20. The battery 100 may also include other structures; for example, the battery 100 may further include bus members for realizing electrical connections between multiple battery cells 10.

[0114] Referring to Figure 2, which is a schematic diagram of the local structure of a battery 100 provided by some embodiments of the present application, the battery 100 includes a plurality of rows of battery cells 10 arranged along a first direction X, and each row of battery cells 10 includes a plurality of battery cells 10 arranged along a second direction Y. The first direction X and the second direction Y are the length direction and width direction of the case 20, respectively, and the first direction X and the second direction Y are perpendicular to each other.

[0115] Each battery cell 10 may be a secondary battery or a primary battery, and may be, but is not limited to, a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery. The shape of the battery cell 10 may be cylindrical, flattened, rectangular, or other shapes. Exemplarily, in Figure 3, the shape of the battery cell 10 is a rectangular parallelepiped. In related art, a battery cell generally includes a casing and a battery core assembly, the casing is fitted with a positive electrode column and a negative electrode column, the battery core assembly is provided inside the casing, the battery core assembly generally includes at least two electrode pieces, some of which are positive electrode pieces and the other half are negative electrode pieces, the positive electrode piece is provided with a positive electrode tab, the negative electrode piece is provided with a negative electrode tab, a separator is provided between the positive electrode piece and the negative electrode piece, the positive electrode tab is electrically connected to the positive electrode column, the negative electrode tab is electrically connected to the negative electrode column, and the casing is filled with electrolyte.

[0116] When combined with Figures 3 to 5 of the attached drawings, the embodiment of the present application provides a battery cell 10 including a casing assembly 1 and a battery core assembly 2. The casing assembly 1 includes a casing 11 and a first pole 12, the first pole 12 including a pole body 1201 attached to the casing 11 and a first cover plate 13 installed on the pole body 1201. The battery core assembly 2 includes an active material coated portion 21 housed within the casing 11 and a conductive portion 22 connected to the active material coated portion 21, which is connected to the pole body 1201 via a first welded portion 71. The shape of the casing 11 is adjusted according to the type of battery cell 10, and the type of battery cell 10 in the embodiment of the present application is not limited. For example, if the battery cell 10 is a rectangular battery, the casing 11 is rectangular, and if the battery cell 10 is a cylindrical battery, the casing 11 is cylindrical, but the embodiment of the present application will be described with a rectangular casing 11.

[0117] The casing 11 is provided with electrode posts, which are used for electrical connection to the battery core assembly 2 to ensure that the charging and discharging operations of the battery cell 10 are performed normally. Generally, there are at least two electrode posts, specifically consisting of at least one positive electrode post and at least one negative electrode post. For example, if there are two electrode posts, one is a positive electrode post and the other is a negative electrode post, and each is electrically connected to the positive and negative output positions of the battery core assembly 2. If there are four electrode posts, two may be positive electrode posts and the remaining two may be negative electrode posts, with both positive electrode posts electrically connected to the positive electrode output positions of the battery core assembly 2 and both negative electrode posts electrically connected to the negative electrode output positions of the battery core assembly 2.

[0118] Simultaneously, Figure 6 is a schematic diagram of the structure of a battery cell 10 provided in some embodiments of the present application, and Figure 7 is an assembly diagram of a second pole 15, a battery core assembly 2, and a casing 11 provided in some embodiments of the present application. Referring to Figures 1 to 7, in the embodiments of the present application, at least one of the multiple poles is a first pole 12, and the first pole 12 may be used as a positive pole or a negative pole.

[0119] Regardless of whether the pole on the casing 11 is the first pole 12 or the second pole 15, both the first pole 12 and the second pole 15 are electrically connected to the battery core assembly 2 to ensure that the charging and discharging process of the battery cell 10 proceeds normally. Of course, in other embodiments of the present invention, only one pole may be installed on the casing assembly 1, and that pole may be the first pole 12, which includes two parts, the two parts of which are insulated and used as the positive pole and the negative pole, respectively. For the sake of simplicity, the following description will mainly focus on embodiments in which all poles in the casing 11 are the first pole 12 forming the housing portion 121.

[0120] What needs to be explained is that, referring to Figures 6 and 7, when the second pole post 15 is installed on the casing 11, the relief groove 18 may be installed between the second pole post 15 and the casing 11 as needed, so that at least a portion of the conductive part 22 is accommodated in the relief groove 18. This reduces the space occupied by the conductive part 22 within the casing 11 to some extent, which is advantageous in improving energy density and mitigating the short-circuit problem caused by the redundancy of the conductive part 22.

[0121] Referring again to Figures 3 to 7, in the embodiment of the present invention, the battery core assembly 2 includes an active material coated portion 21 and a conductive portion 22 housed within the casing 11. The active material coated portion 21 is the portion of the battery core assembly 2 to which the active material is coated, and can assist in the desorption of metal ions during the charging and discharging process of the battery cell 10. The conductive portion 22 is a metal structure that electrically connects the active material coated portion 21 and the electrode poles. The electrode poles are electrically connected to the active material coated portion 21 via the conductive portion 22, allowing the charging and discharging operations of the battery cell 10 to be performed.

[0122] It should be explained that in the embodiment of the present application, the active material coated portion 21 is divided into a positive electrode active material coated portion and a negative electrode active material coated portion. The positive electrode active material coated portion includes the portion of the positive electrode current collector to which the positive electrode active material layer is coated, and the negative electrode active material coated portion includes the portion of the negative electrode current collector to which the negative electrode active material layer is coated. The conductive portion 22 is divided into a positive electrode conductive portion and a negative electrode conductive portion. The positive electrode conductive portion electrically connects the positive electrode active material coated portion and the positive electrode column, and the negative electrode conductive portion electrically connects the negative electrode active material coated portion and the negative electrode column. It should be explained that the method for forming the first welded portion 71 is not limited and includes, for example, laser welding, friction welding, ultrasonic welding, etc., and depending on factors such as the position, angle, and structure of the welded portion, vertical welding, inclined welding, etc., and overlap welding, edge welding, etc., can be selected. Exemplarily, the first welded portion 71 may be a long weld mark in order to improve the reliability of the welding and increase the current passage performance.

[0123] In some embodiments, the conductive part 22 and the pole column body 1201 are welded from the outside to form a first weld 71 between them. The conductive part 22 may be located inside the pole column body 1201, or it may pass through the through-hole of the pole column body 1201 and overlap it on the outside of the pole column body 1201. When the conductive part 22 is located inside the pole column body 1201, the first weld 71 passes through the pole column body 1201 and connects to the conductive part 22. When the conductive part 22 overlaps it on the outside of the pole column body 1201, the first weld 71 passes through the conductive part 22 and connects to the pole column body 1201. Since exposure of the first weld 71 to the outside of the pole column body 1201 may affect the reliability of the weld and subsequent connection with bus members, the first cover plate 13 is installed to fit with the pole column body 1201 and cover the first weld 71.

[0124] In several other embodiments, the conductive part 22 and the pole column body 1201 are welded from the inside to form a first welded joint 71 between them. The conductive part 22 can be located inside the pole column body 1201, or it can pass through the through-hole of the pole column body 1201 and overlap it on the outside of the pole column body 1201. When the conductive part 22 is located inside the pole column body 1201, the first welded joint 71 passes through the conductive part 22 and connects to the pole column body 1201. When the conductive part 22 overlaps on the outside of the pole column body 1201, the first welded joint 71 passes through the pole column body 1201 and connects to the conductive part 22. To ensure the reliability of the weld, the first welded joint 71 is installed by passing through the pole column body 1201 during welding, thereby guaranteeing and increasing the weld strength. In this case, if the first welded portion 71 is exposed to the outside of the pole column body 1201, it may affect the reliability of the weld and the subsequent connection with the bus member. Therefore, the first cover plate 13 is fitted to the pole column body 1201 and installed to cover the first welded portion 71.

[0125] In the above proposed technology, by positioning the first welded portion 71 at least partially away from the active material coated portion 21 of the pole body 1201, it is possible to reduce the amount of metal residue generated during the welding process that enters the battery cell 10, to some extent prevent the metal residue from overlapping with the positive and negative electrode pieces, and reduce the possibility of an internal short circuit in the battery cell 10. On the other hand, if the first welded portion 71 can be separated from the active material coated portion 21, and the pole body 1201 and the conductive portion 22 are welded at a high temperature to form the first welded portion 71, the first welded portion 71, which is a high-temperature heat source, is separated from the active material coated portion 21. This reduces the influence of the high temperature generated by welding on the active material coated portion 21, reduces the probability of damage to the active material coated portion 21, and improves the reliability of the battery cell 10. Furthermore, after the pole column body 1201 is welded to the conductive part 22 inside the casing 11, when the battery cell 10 and bus member 30 are welded, the first cover plate 13 shields the first welded part 71, thereby providing protection and reducing the effect of the high temperature generated when welding the pole column body 1201 and the bus member 30 on the first welded part 71, thereby improving the reliability of the connection between the pole column body 1201 and the conductive part 22.

[0126] For example, the high temperature generated when welding the pole column body 1201 and the bus member 30 will remelt the first welded joint 71 with a certain probability. However, the shielding provided by the first cover plate 13 reduces the high temperature generated when welding the pole column body 1201 and the bus member 30 before it reaches the first welded joint 71. Consequently, the first welded joint 71 between the pole column body 1201 and the conductive part 22 is less likely to remelt, thereby improving the reliability of the battery cell 10 during the manufacturing process. In some embodiments, when Figures 8 and 9 are combined, the pole post body 1201 has a first housing groove 12110, the surface of the first pole post 12 facing the active material coated portion 21 is the pole post inner end face 122, the groove opening of the first housing groove 12110 is formed on the pole post inner end face 122, and the first housing groove 12110 has a first end wall 12111 and a first side wall 12113, the first end wall 12111 is located on the side of the first side wall 12113 away from the active material coated portion 21, at least a portion of the conductive portion 22 is housed in the first housing groove 12110, the first welded portion 71 is provided on the first end wall 12111, and the first cover plate 13 fits with the pole post body 1201 and covers the first welded portion 71.

[0127] Exemplary, the first housing groove 12110 is a groove body, and the groove body is a groove-shaped structure having a certain depth. For example, when the first pole column 12 is installed on the upper end wall of the casing 11 and the inner end face 122 of the pole column is the lower surface of the first pole column 12, the first housing groove 12110 is formed as a housing groove with a groove opening that faces downward and a groove wall that is recessed upward. Also, when the first pole column 12 is installed on the lower end wall of the casing 11 and the inner end face 122 of the pole column is the upper surface of the first pole column 12, the first housing groove 12110 is formed as a housing groove with a groove opening that faces upward and a groove wall that is recessed downward.

[0128] In the above proposed technology, by providing a first housing groove 12110 in the first pole column 12, the weight of the first pole column 12 can be reduced to some extent, thereby improving the gravimetric energy density of the battery cell 10 and the battery 100. At the same time, since the opening of the first housing groove 12110 is formed on the inner end surface 122 of the pole column, and the inner end surface 122 is the surface of the first pole column 12 that is close to the active material coated portion 21, the first housing groove 12110 can be opened in the direction toward the active material coated portion 21, and furthermore, the conductive portion 22 extends into the first housing groove 12110, thereby improving assembly efficiency. Moreover, such a first housing groove 12110 is easy to process, which improves production efficiency.

[0129] Furthermore, the first storage tank 12110 can be easily processed to have a relatively large volume, allowing it to accommodate more conductive parts 22. At the same time, since the first storage tank 12110 is open to the direction of the active material coating part 21, it can also be used as a buffer and temporary storage structure for the electrolyte, allowing more electrolyte to be contained within the casing 11. As the electrolyte is consumed during the charge and discharge process of the battery cell 10, having more electrolyte can extend the service life of the battery cell 10. Moreover, since the first storage groove 12110 is open to the direction of the active material coating part 21, it can also be used as a storage and buffer structure for gases generated inside the battery core assembly 2, reducing the expansion of the battery cell 10 and improving the reliability and stability of the battery cell 10.

[0130] Furthermore, since the first housing groove 12110 is located inside the first pole column 12, it is difficult for external foreign matter and impurities to enter the first housing groove 12110, reducing the impact of external foreign matter and impurities on the battery core assembly 2, improving the stability and reliability of the operation of the battery core assembly 2, and consequently improving the stability and reliability of the battery cell 10 and the battery 100.

[0131] Next, by installing the first welded portion 71 between the pole column body 1201 and the conductive portion 22 on the first end wall 12111, the first welded portion 71 can be further separated from the active material coated portion 21 when it is inside the first housing groove 12110, further reducing the impact on the active material coated portion 21 due to the high temperature generated when welding the pole column body 1201 and the conductive portion 22 to form the first welded portion 71. Furthermore, the first housing groove 12110 not only has the function of housing at least a part of the conductive portion 22, but the groove wall of the first housing groove 12110 also has the function of realizing an electrical connection with the conductive portion 22. As a result, the structure of the first pole column 12 can be simplified, the processing of the first pole column 12 can be made easier, the structure of the conductive portion 22 can also be simplified, the redundancy of the conductive portion 22 can be reduced, and the cost of the conductive portion 22 can be reduced. Furthermore, by utilizing the welding between the first end wall 12111 and the conductive part 22, the welding area formed by the first welded part 71 can be made relatively large, which not only reduces the difficulty of welding but also improves the reliability and stability of the welding, and ultimately improves the performance of the battery cell 10.

[0132] Furthermore, since the first welded portion 71 is located in the first housing groove 12110, it is possible to avoid the first welded portion 71 protruding from the outside of the first pole column 12 and occupying the space outside the first pole column 12. In addition, the first welded portion 71 can be protected by the first cover plate 13, thereby improving the reliability and stability of the welding between the conductive portion 22 and the first pole column 12.

[0133] Furthermore, in the embodiment of the present invention, the first end wall 12111 is a sealed structure without through holes so as to isolate the first housing groove 12110 from the external space of the casing 11, thereby avoiding the problem of electrolyte leakage from the first housing groove 12110 within the casing 11.

[0134] Combining Figures 8 and 9, in several selective embodiments, the local shape of the conductive portion 22 matches the local shape of the first end wall 12111 and is installed in close contact to achieve electrical connection, so that the first weld 71 between the conductive portion 22 and the first end wall 12111 can extend along the length or width direction of the first end wall 12111. For example, if the first end wall 12111 is flat, the local portion of the conductive portion 22 may also be flat and in close contact with the first end wall 12111, and the position of contact may be welded. This can increase the welding area and improve the reliability and stability of the weld.

[0135] It should be explained that the shape of the first end wall 12111 is not limited and may be, for example, a flat plate or an arc-shaped plate. Here, if the first end wall 12111 is a flat plate structure, it is positioned at an angle with the axial direction R of the first pole column 12. For example, it may be a flat plate structure perpendicular to the axial direction R of the first pole column 12, or it may be an inclined plate structure not perpendicular to the axial direction R of the first pole column 12, but the direction of inclination is not limited.

[0136] Of course, in other embodiments of the present application, the first weld 71 between the conductive portion 22 and the first end wall 12111 does not have to extend along the length or width of the first end wall 12111, but may be, for example, a plurality of discretely placed welding points, for example the conductive portion 22 has a plurality of spaced-apart locations that are each welded to the first end wall 12111, but such a description is omitted here.

[0137] In some embodiments, when Figure 10 is combined, the first end wall 12111 has a first recessed groove 12112, and at least a portion of the first welded portion 71 is located within the first recessed groove 12112. It can be understood that the recessing direction of the first recessed groove 12112 is away from the active material coated portion 21, and exemplary, at least a portion of the conductive portion 22 may be placed within the first recessed groove 12112 and connected to a portion of the first end wall 12111 that defines the first recessed groove 12112.

[0138] In the above proposed technology, the first recessed groove 12112 can be used to pre-position and restrict the first welded portion 71, which is advantageous not only for finding the appropriate position for welding and improving production efficiency, but also for improving the stability and reliability of the conductive portion 22 and ensuring the stability and reliability of the charging and discharging process of the battery cell 10. Furthermore, by installing the first recessed groove 12112 in the first end wall 12111, the local thickness of the first end wall 12111 can be locally reduced, which is advantageous not only for welding but also for reducing the weight of the first pole column 12, thereby improving the gravimetric energy density of the battery cell 10.

[0139] In several selective embodiments, a portion of the conductive portion 22 is fitted in close contact with the shape of the first side wall 12113. For example, if the first side wall 12113 is curved, a portion of the conductive portion 22 is also curved and fits in close contact with the first side wall 12113. The contact position is welded such that the first weld 71 between the conductive portion 22 and the first side wall 12113 extends along the first side wall 12113. As a result, the welding area can be increased, improving the reliability and stability of the weld.

[0140] Of course, the present application is not limited thereto, and in other embodiments of the present application, the first weld 71 between the conductive portion 22 and the first side wall 12113 does not have to extend along the first side wall 12113, but may be, for example, a plurality of discretely placed welding points, for example the conductive portion 22 has a plurality of spaced-apart locations that are welded to the first side wall 12113, but such a description is omitted here.

[0141] It should be explained that there is no limit to the number of first side walls 12113, and may be determined according to the shape of the first receiving groove 12110, provided that one end of each first side wall 12113 away from the groove opening of the first receiving groove 12110 is connected to the first end wall 12111. For example, if the cross-sectional shape of the first receiving groove 12110 is circular or elliptical, the first end wall 12111 is circular or elliptical, and there is one first side wall 12113, which is formed in a ring shape and installed around the periphery of the first end wall 12111. For example, if the cross-sectional shape of the first receiving groove 12110 is rectangular or racetrack-shaped, the first end wall 12111 is rectangular or racetrack-shaped, and there are four first side walls 12113, each connected to one of the four sides of the first end wall 12111.

[0142] Furthermore, it should be explained that the first accommodating groove 12110 is not limited to being defined by a first end wall 12111 and a first side wall 12113. For example, in some embodiments, the first end wall 12111 may not be present. In that case, the first accommodating groove 12110 can be defined by a plurality of first side walls 12113, with the ends of each first side wall 12113 that are away from the groove opening of the first accommodating groove 12110 converging. In this case, the conductive portion 22 is electrically connected to the first side walls 12113, and it is sufficient that the charging and discharging process of the battery cell 10 is ensured to proceed normally.

[0143] Furthermore, it should be noted that in other embodiments of the present invention, the first welded portion 71 between the conductive portion 22 and the first pole column 12 does not necessarily have to be located in the first housing groove 12110. For example, the first welded portion 71 between the conductive portion 22 and the first pole column 12 may be located on the inner end face 122 of the pole column. In this case, a portion of the conductive portion 22 is housed within the first housing groove 12110, which also saves some space and improves the energy density of the battery cell 10.

[0144] Combining Figures 9 and 10, in some embodiments, the first pole column 12 has a first groove 126, the surface of the first pole column 12 away from the active material coated portion 21 is the pole column outer end surface 123, the groove opening of the first groove 126 is formed on the pole column outer end surface 123, and the first cover plate 13 seals the groove opening of the first groove 126.

[0145] As can be understood, the first groove 126 is a groove body, and the groove body is a groove-like structure having a certain depth. Furthermore, when the first pole column 12 is installed on the upper end wall of the casing 11 and the outer end surface 123 of the pole column is the upper surface of the first pole column 12, the first groove 126 is formed as a groove with an opening that faces upward and a groove wall that is recessed downward (i.e., recessed in the direction approaching the battery core assembly 2). Alternatively, for example, when the first pole column 12 is installed on the lower end wall of the casing 11 and the outer end surface 123 of the pole column is the lower surface of the first pole column 12, the first groove 126 is formed as a groove with an opening that faces downward and a groove wall that is recessed upward (i.e., recessed in the direction approaching the battery core assembly 2).

[0146] In the above proposed technology, since the first groove 126 is installed in the first pole column 12, the weight of the first pole column 12 can be further reduced, and the gravimetric energy density of the battery cell 10 and the battery 100 can be improved. On the other hand, since the first groove 126 is located on the outside of the first pole column 12, that is, it is open to the side away from the inside of the casing 11 of the first pole column 12, the first groove 126 can accommodate or attach structural members that are electrically connected to each battery cell 10 in the battery 100, making full use of the space inside the first pole column 12 and improving the space utilization rate and volumetric energy density of the battery 100. By installing the first groove 126 and having the first cover plate 13 seal the groove opening of the first groove 126, welding of the first cover plate 13 becomes easier and assembly efficiency is improved.

[0147] Furthermore, since the first pole column 12 has both a first housing groove 12110 and a first recessed groove 126, and the first recessed groove 126 is located on the side of the first housing groove 12110 away from the active material coated portion 21, and the first recessed groove 126 is open facing in a direction away from the first housing groove 12110, it becomes easy to laser weld the conductive portion 22 and the first end wall 12111 via the first recessed groove 126 from the outside of the first pole column 12, i.e., from the side of the first pole column 12 away from the active material coated portion 21, which is advantageous for easily realizing an electrical connection between the conductive portion 22 and the first pole column 12 by external welding. In other words, the above structure makes it easy to externally weld the first pole column 12 and the conductive portion 22 via the first recessed groove 126, facilitating the processing and manufacturing of the battery cell 10 and saving processing and manufacturing costs.

[0148] Furthermore, in order to easily and effectively weld the conductive portion 22 and the groove wall of the first housing groove 12110 via the first recessed groove 126 and to improve the reliability of the welding between the conductive portion 22 and the groove wall of the first housing groove 12110, in the embodiment of the present application, the portion between the first recessed groove 126 and the first housing groove 12110 can be laser-welded to the conductive portion 22. That is, the gap portion 127 shown in Figure 10 and the conductive portion 22 are laser-welded to realize an electrical connection between the battery core assembly 2 and the first pole column 12. The gap portion 127 between the first groove 126 and the first housing groove 12110 of the first pole column 12 is thin in thickness, and the gap portion 127 separates the first groove 126 and the first housing groove 12110. The wall surface of the gap portion 127 on the side close to the active material coated portion 21 can be the first end wall 12111. When it is necessary to weld the conductive portion 22 to the first end wall 12111, the relatively thin thickness of the gap portion 127 is advantageous for welding the conductive portion 22 to the first end wall 12111 via the first groove 126, improving the convenience and reliability of welding.

[0149] In some embodiments, the first housing groove 12110 may be configured in a shape such as a rectangle, ellipse, or racetrack shape, where the length of the cross-section is greater than the width. The first welded portion 71 formed by welding the conductive portion 22 to the first pole column 12 may be a long weld parallel to the length of the first housing groove 12110 in order to improve welding reliability and increase current flow performance. For example, when the conductive portion 22 to the first end wall 12111 is welded to form the first welded portion 71, which is a long weld, the width of the weld may be 6 mm or more, and the distance between the weld and the first side wall 12113 may be 1 mm or more, in order to ensure the convenience and reliability of welding and to ensure the current flow capability of the battery cell 10.

[0150] As shown in Figure 9, by installing the first cover plate 13 which seals the first groove 126, the first pole column 12 can be indirectly electrically connected to the bus member 30 via the first cover plate 13. The position and structure of the first cover plate 13 make the electrical connection between the first cover plate 13 and the bus member 30 more convenient and increase the electrical connection area. Therefore, by installing the first cover plate 13, the electrical connection between adjacent battery cells 10 in the battery 100 becomes easier, and because the electrical connection position between the battery cells 10 is located on the first cover plate 13, the first groove 126 separates it from the first welded portion 71 between the conductive part 22 and the first pole column 12, reducing interference between the two and further improving the stability and reliability of the battery cell 10.

[0151] It should be noted that the specific structure of the battery core assembly 2 in the embodiments of the present application is not limited and may include, but is not limited to, the following two embodiments.

[0152] In some embodiments, combining Figures 9 to 11, the active material coated portion 21 includes a current collector 211 and an active material layer 212 provided on the current collector 211, the conductive portion 22 includes a tab portion 221 electrically connected to the current collector 211, the tab portion 221 includes a plurality of tab sheets 2211, the plurality of tab sheets 2211 gather at a position close to the current collector 211 (i.e., gather in a direction toward each other) to form a first convergence portion 2212, the plurality of tab sheets 2211 gather and connect at a position away from the current collector 211 to form a second convergence portion 2213, the first convergence portion 2212 connects the second convergence portion 2213 to the active material coated portion 21, at least a portion of the second convergence portion 2213 is housed in a first housing groove 12110, and the second convergence portion 2213 is connected to a first end wall 12111 via a first weld portion 71.

[0153] In the above-described technical proposal, the multiple tab sheets 2211 simply come together (i.e., converge toward each other) when forming the first convergence portion 2212, but do not connect. However, when forming the second convergence portion 2213, the multiple tab sheets 2211 not only come together but also connect to form an integrated structure. For example, the second convergence portion 2213 may be formed by a plate structure in which the multiple tab sheets 2211 are integrally connected by welding (e.g., ultrasonic welding). However, the present application is not limited to these methods, and the second convergence portion 2213 may also be formed by connecting the multiple tab sheets 2211 while they converge, for example, by adhesion with a conductive adhesive, but this will not be explained in detail here.

[0154] To explain further, in the embodiment of the present application, the tab sheet 2211 is divided into a positive electrode tab sheet 2211 and a negative electrode tab sheet 2211. The positive electrode tab sheets 2211 that need to be converged are stacked and ultrasonically tack-welded to form a second convergence portion 2213 of the positive electrode, thereby reducing the interlayer gap and forming a plate-like structure with a certain degree of rigidity from the multiple soft positive electrode tab sheets 2211. Similarly, the negative electrode tab sheets 2211 that need to be converged are stacked and ultrasonically tack-welded to form a second convergence portion 2213 of the negative electrode, thereby reducing the interlayer gap and forming a plate-like structure with a certain degree of rigidity from the multiple soft negative electrode tab sheets 2211.

[0155] In the above proposed technology, the statement "multiple tab sheets 2211 gather at a position close to the current collector 211 to form a first convergence section 2212, and multiple tab sheets 2211 gather at a position away from the current collector 211 and connect to form a second convergence section 2213" means that along the extending direction of the tab sheets 2211, the first convergence section 2212 and the second convergence section 2213 are installed sequentially along the direction away from the current collector 211, and the specific positions of the first convergence section 2212 and the second convergence section 2213 are not limited; that is, it is not required how close the first convergence section 2212 is to the current collector 211 or how far the second convergence section 2213 is from the current collector 211. In some selective embodiments, the current collector 211 and the tab sheet 2211 may be an integral component, for example, an aluminum foil integrally molded with respect to the positive electrode piece, or a copper foil integrally molded with respect to respect to respect to respect to respect to respect to respect to respect to respect to respect to respect.

[0156] In the above proposed technology, the tab portion 221 includes a second convergence portion 2213 formed by the aggregation and connection of multiple tab sheets 2211. Therefore, at least a portion of the second convergence portion 2213 is housed in the first accommodating groove 12110, facilitating the connection between the conductive portion 22 and the first pole column 12, allowing for full utilization of the space of the first pole column 12, and improving the volumetric energy density of the battery cell 10.

[0157] Combining Figures 9 to 11, in the first embodiment, since at least a portion of the second convergence portion 2213 is housed in the first housing groove 12110, the space of the first pole column 12 can be utilized more effectively, the space occupied by the tab portion 221 within the casing 11 can be further reduced, a larger active material coated portion 21 can be housed, the volumetric energy density of the battery cell 10 can be improved, and the redundancy of the tab portion 221 within the casing 11 can be more appropriately reduced, further reducing the probability of a short circuit between the tab portion 221 and the active material coated portion 21.

[0158] In this embodiment, the second convergence portion 2213 is connected to the first end wall 12111 via the first weld portion 71. For example, when the second convergence portion 2213 and the first end wall 12111 are welded together via the first weld portion 71, for example, when the second convergence portion 2213 is welded to the first end wall 12111 (e.g., by laser welding), the configuration of the battery core assembly 2 can be simplified, the number of components can be reduced, the assembly process can be simplified, and the assembly efficiency can be improved. Of these, the first weld 71 between the second convergence portion 2213 and the first end wall 12111 may extend along the length or width direction of the first end wall 12111. Furthermore, the first end wall 12111 may have a first recessed groove 12112, and the first weld 71 between the second convergence portion 2213 and the first end wall 12111 may be located within the first recessed groove 12112. The corresponding technical effects can be found in the description of the above embodiment and will not be described again here.

[0159] When Figure 10 is combined, in some embodiments, the active material coated portion 21 includes a current collector 211 and an active material layer 212 provided on the current collector 211, the conductive portion 22 includes a tab portion 221 and an adapter sheet 222, the tab portion 221 includes a plurality of tab sheets 2211, the plurality of tab sheets 2211 gather at a position close to the current collector 211 to form a first convergence portion 2212, the plurality of tab sheets 2211 gather and connect at a position away from the current collector 211 to form a second convergence portion 2213, the first convergence portion 2212 connects the second convergence portion 2213 and the active material coated portion 21, the adapter sheet 222 is connected to the second convergence portion 2213, at least a portion of the adapter sheet 222 is housed in a first housing groove 12110, and the adapter sheet 222 is connected to a first end wall 12111 via a first weld portion 71.

[0160] In the above proposed technology, the active material coated portion 21 can achieve electrical connection with the first pole column 12 via the first convergence portion 2212, the second convergence portion 2213, and the adapter sheet 222, respectively. The electrical connection position between the conductive portion 22 and the first pole column 12 is located on the adapter sheet 222, and the electrical connection can be achieved, for example, by welding (e.g., laser welding) the adapter sheet 222 and the first pole column 12. Furthermore, the adapter sheet 222 and the tab sheet 2211 are two separate members and are connected by a method such as welding (e.g., ultrasonic welding).

[0161] In the above proposed technology, at least a portion of the adapter sheet 222 is housed in the first housing groove 12110, allowing for more efficient use of the space within the first pole column 12, further reducing the space occupied by the conductive part 22 within the casing 11, and improving the volumetric energy density of the battery cell 10. On the other hand, by using the adapter sheet 222 and the first welded portion 71 to achieve an indirect electrical connection between the second convergence portion 2213 and the first pole column 12, the adapter sheet 222 can be welded to the first pole column 12 using the portion of the adapter sheet 222 that avoids the second convergence portion 2213. This ensures a secure weld between the adapter sheet 222 and the first pole column 12, reducing the risk of welding cracks and further improving the reliability and stability of the battery cell 10. At the same time, electrically connecting the first pole column 12 and the tab sheet 2211 via the adapter sheet 222 simplifies the structure of the tab sheet 2211.

[0162] The method and location of connection of the first weld 71 between the adapter sheet 222 and the first pole column 12 are not limited. For example, the first weld 71 between the adapter sheet 222 and the first pole column 12 may be located on the first end wall 12111 and / or the first side wall 12113, and furthermore, the first weld 71 between the adapter sheet 222 and the first end wall 12111 may extend along the length or width direction of the first end wall 12111, and furthermore, the first end wall 12111 may have a first recessed groove 12112, and the first weld 71 between the adapter sheet 222 and the first end wall 12111 may be located within the first recessed groove 12112, and the corresponding technical effects can be found in the description of the above embodiment, which is omitted here. When the first weld 71 between the adapter sheet 222 and the first pole column 12 is located at the first end wall 12111 and / or the first side wall 12113, at least a portion of the adapter sheet 222 is housed in the first housing groove 12110, thus simplifying the structure of the adapter sheet 222, reducing redundancy, and lowering costs.

[0163] By combining Figures 9 to 11, in some embodiments, at least a portion of the first convergence portion 2212 is housed in the first housing groove 12110. In the above technical proposal, by housing at least a portion of the first convergence portion 2212 of the tab portion 221 in the first housing groove 12110, the space within the first pole column 12 can be utilized more effectively, the space occupied by the tab portion 221 within the casing 11 can be further reduced, a larger active material coated portion 21 can be housed, the volumetric energy density of the battery cell 10 can be improved, the redundancy of the tab portion 221 within the casing 11 can be more appropriately reduced, and the probability of a short circuit between the tab portion 221 and the active material coated portion 21 can be further reduced.

[0164] Combining Figures 10 and 11, in the second embodiment, the active material coated portion 21 includes a current collector 211 and an active material layer 212 provided on the current collector 211, the conductive portion 22 includes a tab portion 221 and an adapter sheet 222, the tab portion 221 includes a plurality of tab sheets 2211 electrically connected to the current collector 211, the plurality of tab sheets 2211 gather at a position close to the current collector 211 to form a first convergence portion 2212, the plurality of tab sheets 2211 gather and connect at a position away from the current collector 211 to form a second convergence portion 2213, and the adapter sheet 222 is electrically connected to the second convergence portion 2213. If the housing portion 121 has a first housing groove 12110, at least a portion of the adapter sheet 222 can be housed in the first housing groove 12110 and electrically connected to the first pole column 12.

[0165] In the above-described technical proposal, the second embodiment, compared to the technical proposal including the adapter sheet 222 of the first embodiment, has at least a portion of the adapter sheet 222 housed in the first housing groove 12110. However, the relative position of the tab portion 221 and the first housing groove 12110 is not restricted. That is, at least a portion of the tab portion 221 can be housed in the first housing groove 12110, or the tab portion 221 can be located entirely outside the first housing groove 12110. This allows for the fulfillment of different structural design requirements.

[0166] In the above proposed technology, by housing at least a portion of the adapter sheet 222 in the first housing groove 12110, the adapter sheet 222 can occupy space within the first pole column 12. This reduces the space occupied by the adapter sheet 222 within the casing 11, allowing for the accommodation of a larger active material coated portion 21 and improving the volumetric energy density of the battery cell 10. Furthermore, it reduces the probability of short circuits between the adapter sheet 222 and the active material coated portion 21, thereby reducing the risk of short circuits in the battery core assembly 2 and improving the stability and reliability of the battery cell 10. In addition, housing at least a portion of the conductive portion 22 in the housing portion 121 is advantageous for stabilizing and positioning the conductive portion 22, improving the stability of the conductive portion 22, facilitating welding between the conductive portion 22 and the first pole column 12, and improving assembly efficiency.

[0167] Furthermore, by using the adapter sheet 222 to achieve an indirect electrical connection between the second convergence section 2213 and the first pole column 12, the adapter sheet 222 can be welded to the first pole column 12 using the portion of the adapter sheet 222 that avoids the second convergence section 2213. This ensures a secure weld between the adapter sheet 222 and the first pole column 12, reducing the risk of welding cracks and further improving the reliability and stability of the battery cell 10. At the same time, electrically connecting the first pole column 12 and the tab sheet 2211 via the adapter sheet 222 simplifies the structure of the tab sheet 2211.

[0168] For example, in some selective embodiments, such as Embodiment 1 above or the third embodiment below, when the second convergence portion 2213 is directly electrically connected to the first pole 12, the conductive portion 22 may consist only of the positive and negative tabs of each electrode assembly 2a. For example, in some other embodiments, such as Embodiment 1 or Embodiment 2 above, or the third or fourth embodiment below, when the second convergence portion 2213 is indirectly electrically connected to the first pole 12 by an adapter sheet 222, the conductive portion 22 may consist of the positive tab, the negative tab of each electrode assembly 2a, and the adapter sheet 222.

[0169] In some embodiments, when the battery core assembly 2 includes two electrode assemblies 2a, the tab sheets 2211 of the two electrode assemblies 2a can converge together, and the convergence position is centrally located between the two electrode assemblies 2a, forming a symmetrically converged shape (for example, as shown in Figures 11 and 12(a)). In some other embodiments, when the tab sheets 2211 of the two electrode assemblies 2a converge together, the convergence position may be close to one electrode assembly 2a, forming an asymmetrically converged shape (for example, as shown in Figures 12(b) and 12(c)). Furthermore, the electrode assembly 2a may be in a fully extended tab configuration (for example, as shown in Figure 12(a)) or a half-extended tab configuration (for example, as shown in Figures 11, 12(b), and 12(c)).

[0170] Of course, this invention is not limited to this, and the tab sheets 2211 of the same polarity in the two electrode assemblies 2a do not have to converge together. For example, the tab sheets 2211 of each electrode assembly 2a may converge independently at the positive and negative electrodes, that is, the positive electrode tab of one electrode assembly 2a may converge independently, and the positive electrode tab of the other electrode assembly 2a may also converge independently, but the explanation of this is omitted here.

[0171] It should be noted that the housing portion 121 in the embodiment of the present application is not necessarily limited to having a first housing groove 12110, and several other optional embodiments are shown below, for example.

[0172] When Figure 8 is combined, in some embodiments, the casing 11 has a mounting hole 113, the first pole post 12 is attached to the mounting hole 113, and along the axial direction of the first pole post 12, the depth H1 of the first housing groove 12110 is greater than or equal to the minimum distance H2 from the inner end face 122 of the pole post to the mounting hole 113.

[0173] It should be noted that the specific shape of the first accommodating groove 12110 is not limited. For example, it may be a cylindrical groove with a rectangular, elliptical, or racetrack-shaped cross-section, a trapezoidal groove with a rectangular cross-section and gradually changing cross-sectional dimensions, a hemispherical groove with a circular cross-section and gradually changing cross-sectional dimensions, or a semi-elliptical groove with an elliptical cross-section and gradually changing cross-sectional dimensions. It may have a regular or irregular shape. Therefore, the depth H1 of the first accommodating groove 12110 refers to the maximum depth of the first accommodating groove 12110 along the axial radius R of the first pole column 12.

[0174] In the axial direction R of the first pole column 12, the depth H1 of the first housing groove 12110 is greater than or equal to the minimum distance H2 from the inner end face 122 of the pole column to the mounting hole 113. Therefore, the volume of the first pole column 12 can be fully utilized, and the first housing groove 12110 has a relatively large depth, which is advantageous for accommodating more conductive parts 22. Furthermore, it can further reduce the space occupied by the conductive parts 22 within the casing 11, further improving the energy density of the battery cell 10 and further reducing the redundancy of the conductive parts 22 within the casing 11. At the same time, because the first housing groove 12110 has a relatively large depth, it can accommodate gas generated in the battery core assembly 2, not only ensuring the reliability and stability of the battery cell 10, but also allowing for the accommodation of more electrolyte, thus ensuring the service life of the battery cell 10.

[0175] It should be noted that the volume of the first housing groove 12110 is not limited. For example, in some specific cases, the volume of the first housing groove 12110 for housing the conductive part 22 (denoted as the first volume V1) is 298 mm³. 3 The first housing groove 12110 may have a relatively sufficient space for housing the conductive part 22, thereby facilitating welding between the conductive part 22 and the first pole column 12. On the other hand, the first volume V1 of the first housing groove 12110 is 298 mm 3 If the value is less than the specified value, the capacity of the first housing groove 12110 to accommodate the conductive part 22 becomes relatively low, making it difficult to weld the conductive part 22 to the first pole column 12.

[0176] What needs to be explained is that the first volume V1 of the first receiving groove 12110 is the difference between the total volume V2 of the first receiving groove 12110 and the volume required for the first receiving groove 12110 to accommodate members other than the conductive part 22 (denoted as the second volume V3), that is, V1 = V2 - V3. As can be understood, when the first receiving groove 12110 does not need to accommodate other components other than the conductive part 22, the second volume V3 can be 0 mm 3 and may be. For example, the first volume V1 of the first receiving groove 12110 can be 300 mm 3 ~1500 mm 3 and may be, for example, 300 mm 3 , 400 mm 3 , 500 mm 3 , 600 mm 3 , 700 mm 3 , 800 mm 3 , 1000 mm 3 , 1200 mm 3 , 1400 mm 3 , 1500 mm 3 and so on.

[0177] Alternatively, when combined with FIG. 8, the first receiving groove 12110 may be installed corresponding to the position of the mounting hole 113. In other words, on the projection plane perpendicular to the axial direction R of the first pole 12, the front projection of the first receiving groove 12110 is located within the front projection range of the mounting hole 113, so that the first receiving groove 12110 has a greater depth and can accommodate more conductive parts 22, and thus the space occupied by the conductive parts 22 in the casing 11 can be significantly reduced.

[0178] In some embodiments, when combined with FIG. 13, the pole body 1201 has a second receiving groove 12120. The surface of the pole body 1201 on the side away from the active material coating portion 21 is the pole outer end face 123. The groove opening of the second receiving groove 12120 is formed on the pole outer end face 123. The second receiving groove 12120 has a second end wall 12121 close to the active material coating portion 21. The first welding portion 71 is provided on the second end wall 12121. The first cover plate 13 fits with the pole body 1201 and seals the groove opening of the second receiving groove 12120.

[0179] As can be understood, the second housing groove 12120 is a groove body, and the groove body is a groove-shaped structure having a certain depth. For example, when the first pole column 12 is installed on the upper end wall of the casing 11 and the outer end surface 123 of the pole column is the upper surface of the first pole column 12, the second housing groove 12120 is formed as a housing groove with a groove opening that faces upward and a groove wall that is recessed downward. Also, for example, when the first pole column 12 is installed on the lower end wall of the casing 11 and the outer end surface 123 of the pole column is the lower surface of the first pole column 12, the second housing groove 12120 is formed as a housing groove with a groove opening that faces downward and a groove wall that is recessed upward.

[0180] In the above proposed technology, when Figure 13 is combined, by installing the second housing groove 12120 on the first pole column 12, the weight of the first pole column 12 can be reduced to some extent, thereby improving the gravimetric energy density of the battery cell 10 and the battery 100. On the other hand, since the groove opening of the second housing groove 12120 is formed on the outer end surface 123 of the pole column, and the outer end surface 123 is the surface of the first pole column 12 that is away from the active material coated portion 21, the second housing groove 12120 is the active material The coating portion 21 can be opened in a direction away from it, and by housing at least a portion of the conductive portion 22 in the second housing groove 12120, the conductive portion 22 can be easily housed and organized through the groove opening of the second housing groove 12120, and electrical connection operations between the conductive portion 22 and the first pole column 12 can be easily performed through the groove opening of the second housing groove 12120, thereby reducing the difficulty of producing the battery cell 10 and improving the production efficiency of the battery cell 10.

[0181] Of these, the first welded portion 71 is provided on the second end wall 12121. In other words, the second housing groove 12120 not only has the function of housing at least a part of the conductive portion 22, but the groove wall of the second housing groove 12120 also has the function of realizing welding with the conductive portion 22. This simplifies the structure of the first pole column 12 and makes it easier to process the first pole column 12. Furthermore, the opening direction of the groove opening of the second housing groove 12120 facilitates the welding operation between the conductive portion 22 and the groove wall of the second housing groove 12120 via the groove opening, reducing the difficulty of welding. Moreover, by realizing a welded connection with the conductive portion 22 using the groove wall of the second housing groove 12120, the welding area formed by the first welded portion 71 between the conductive portion 22 and the first pole column 12 can be made relatively large, improving the reliability and stability of the electrical connection and, consequently, improving the performance of the battery cell 10.

[0182] Furthermore, since the first weld 71 between the conductive part 22 and the first pole column 12 is located within the second housing groove 12120, it is possible to avoid the position of the first weld 71 protruding from the outside of the first pole column 12 and occupying the space outside the first pole column 12. Moreover, the position of the first weld 71 provides protection for the first pole column 12, thereby improving the reliability and stability of the electrical connection between the conductive part 22 and the first pole column 12.

[0183] By combining Figures 13 and 14, in some embodiments, the local shape of the conductive portion 22 matches the local shape of the second end wall 12121 and is installed in close contact to achieve electrical connection. Therefore, the first welded portion 71 between the conductive portion 22 and the second end wall 12121 can extend along the length or width direction of the second end wall 12121. For example, if the second end wall 12121 is flat, the local portion of the conductive portion 22 may also be flat and in close contact with the second end wall 12121, and the position of that close contact may be welded. This makes it possible to increase the area of ​​the first welded portion 71 and improve the reliability and stability of the weld.

[0184] It should be noted that the shape of the second end wall 12121 is not limited and can be, for example, a flat plate or an arc-shaped plate. Here, if the second end wall 12121 is a flat plate structure, it is positioned at an angle with the axial direction R of the first pole column 12. For example, it may be a flat plate structure perpendicular to the axial direction R of the first pole column 12, or it may be an inclined flat plate structure not perpendicular to the axial direction R of the first pole column 12, but the direction of inclination is not limited.

[0185] In the above proposed technology, the conductive part 22 is connected to the pole column body 1201 via the first welded part 71. Welding slag is present in the first welded part 71. Since the first welded part 71 is provided on the second end wall 12121, the welding slag can be separated from the active material coated part 21, reducing the amount of welding slag that enters the casing 11. Meanwhile, the first cover plate 13 shields the first welded part 71, protecting it. As a result, welding slag or a portion of the welding slag that falls onto the first welded part 71 is blocked by the first cover plate 13, further reducing the amount of welding slag that enters the casing 11. By reducing the entry of welding slag into the casing 11 by two steps, the risk of short circuits inside the battery cell 10 due to the presence of welding slag can be significantly reduced, improving the reliability of the battery cell 10.

[0186] Furthermore, when the battery cell 10 transmits electricity to the outside, the pole body 1201 needs to be electrically connected to the bus member 30. In this case, the pole body 1201 and the bus member 30 are welded together. However, in such a situation, the first cover plate 13 can shield the first weld 71, so that the bus member 30 does not come into contact with the first weld 71, or the bus member 30 and the first weld 71 can be isolated from each other. This reduces the influence that the first weld 71 has on other weld locations of the pole body 1201.

[0187] In some embodiments, when Figure 55 is combined, the conductive portion 22 is located on the side of the second end wall 12121 facing the active material coated portion 21. In this situation, the first weld portion 71 is provided on the side of the second end wall 12121 facing the active material coated portion 21, and in this case, the distance between the first weld portion 71 and the surface of the pole column body 1201 located on the outside of the casing 11 is relatively large, so the influence of the high temperature formed during welding of the pole column body 1201 and the bus member 30 on the first weld portion 71 can be reduced.

[0188] When Figure 13 is combined, in some embodiments, the second housing groove 12120 communicates with the interior of the casing 11 via the first through hole 12130, the conductive portion 22 is drilled in the first through hole 12130 and is at least partially housed in the second housing groove 12120, and the conductive portion 22 is positioned at least partially away from the active material coated portion 21 of the second end wall 12121.

[0189] Since the second housing groove 12120 communicates with the inside of the casing 11 via the first through hole 12130, the second housing groove 12120 can be used as a buffer and temporary storage structure for the electrolyte, allowing more electrolyte to be contained within the casing 11. As the battery cell 10 loses electrolyte during the charge and discharge process, more electrolyte can extend the service life of the battery cell 10. Furthermore, since the second housing groove 12120 communicates with the inside of the casing 11 via the first through hole 12130, the second housing groove 12120 can be used as a containment and buffer structure for gases generated inside the battery core assembly 2, reducing the expansion of the battery cell 10 and improving the reliability and stability of the battery cell 10.

[0190] It should be explained that when the housing portion 121 has a second housing groove 12120, and the conductive portion 22 is drilled in the first through hole 12130 and is at least partially housed in the second housing groove 12120, the welding position between the conductive portion 22 and the first pole column 12 is not limited.

[0191] Exemplary, when the conductive portion 22 is drilled in the first through hole 12130 and at least partially housed in the second housing groove 12120, in some embodiments of the present application, the first weld 71 between the conductive portion 22 and the first pole post 12 is located in the hole wall of the first through hole 12130 formed by the first pole post 12.

[0192] In the above proposed technology, by installing the first welded portion 71 between the conductive portion 22 and the first pole column 12 on the hole wall of the first through hole 12130, welding operations between the conductive portion 22 and the first pole column 12 can be easily performed via the second accommodating groove 12120. Furthermore, when the welding area between the conductive portion 22 and the first pole column 12 is relatively large, the welding between the conductive portion 22 and the first pole column 12 can be used to seal the first through hole 12130, thereby saving sealing costs and reducing electrolyte leakage, thus saving on sealing materials.

[0193] Specifically, by welding the conductive part 22 to the hole wall of the first through-hole 12130 at the position where the first through-hole 12130 and the second housing groove 12120 are connected, operation is made easier. Furthermore, by controlling the weld marks, the first through-hole 12130 can be sealed using the weld marks and the conductive part 22, thereby improving the problem of electrolyte leakage from the casing 11 through the first through-hole 12130.

[0194] Furthermore, exemplary, when the conductive portion 22 is drilled in the first through hole 12130 and at least partially housed in the second housing groove 12120, in some other embodiments of the present application, the first weld 71 between the conductive portion 22 and the first pole post 12 may also be located on the groove wall of the second housing groove 12120 formed by the first pole post 12. This facilitates electrical connection operations and improves the problem of conductive particles produced by welding entering the casing 11 and causing short circuits, for example, when the conductive portion 22 is welded to the groove wall of the second housing groove 12120 formed by the first pole post 12.

[0195] In some embodiments, when Figures 13 and 14 are combined, the second accommodating groove 12120 further has a second side wall 12123, the second side wall 12123 is located on the side of the second end wall 12121 away from the active material coated portion 21, and the second side wall 12123 and the second end wall 12121 surround each other to form the second accommodating groove 12120, the first through hole 12130 is opened in the second end wall 12121, the second end wall 12121 has a second recessed groove 12122, and at least a portion of the first welded portion 71 is located within the second recessed groove 12122.

[0196] In the above proposed technology, since the first through-hole 12130 is provided in the second end wall 12121, the conductive part 22 can easily enter the second housing groove 12120 through the first through-hole 12130, simplifying the structure of the conductive part 22, reducing the redundancy of the conductive part 22, and lowering the cost of the conductive part 22.

[0197] On the other hand, the portion of the first weld 71 located within the second recessed groove 12122 is positioned to match the shape of the second recessed groove 12122 and is positioned tightly to enable welding. The first weld 71 on the conductive part 22 can be pre-positioned and restricted using the second recessed groove 12122, which is advantageous for finding an appropriate position to achieve welding and for improving production efficiency, as well as improving the stability and reliability of the welding position and ensuring the reliability and stability of the charging and discharging operations of the battery cell 10.

[0198] Combining Figures 13 and 14, the second end wall 12121 may have a flat plate structure, and the angle θ between the second end wall 12121 and the axial R of the first pole column 12 is 90°, that is, the distance between the second end wall 12121 and the active material coated portion 21 is equal along the direction from the first through hole 12130 to the second side wall 12123. This facilitates welding between the conductive portion 22 and the second end wall 12121.

[0199] Furthermore, for example, when Figure 15 is combined, the angle θ between the second end wall 12121 and the axial R of the first pole column 12 is greater than 90°, meaning that the second end wall 12121 extends obliquely along the direction from the first through hole 12130 to the second side wall 12123, facing in a direction close to the active material coated portion 21. This allows the extension distance of the conductive portion 22 along the second end wall 12121 to be increased, thereby improving the reliability of the electrical connection. For example, the angle θ between the second end wall 12121 and the axial direction R of the first pole column 12 is 90° to 145°, and may be, for example, 100°, 110°, 120°, 130°, 140°, etc. This makes it easier to process the second end wall 12121 and to easily connect it electrically to the conductive part 22, while also allowing the conductive part 22 to be housed using the space inside the first pole column 12 relatively sufficiently.

[0200] Furthermore, for example, when Figure 16 is combined, the angle θ between the second end wall 12121 and the axial R of the first pole column 12 is less than 90°, that is, the second end wall 12121 extends obliquely in the direction away from the active material coated portion 21 along the direction from the first through hole 12130 to the second side wall 12123. This allows the extension distance of the conductive portion 22 along the second end wall 12121 to be increased, improving the reliability of the electrical connection. Exemplarily, the angle θ between the second end wall 12121 and the axial R of the first pole column 12 may be 45° to 90°, for example, 50°, 60°, 70°, 80°, etc. This makes it easier to process the second end wall 12121 and to weld it with the conductive portion 22, while also allowing sufficient use of the space within the first pole column 12 to accommodate the conductive portion 22.

[0201] Of course, the present application is not limited thereto, and in other embodiments of the present application, the first welded portion 71 between the conductive portion 22 and the second end wall 12121 does not have to extend along the length or width of the second end wall 12121, but may be a plurality of discretely placed points. For example, the conductive portion 22 has a plurality of spaced locations that are welded to the second end wall 12121, but such a description is omitted here.

[0202] Reassessing Figure 14, regardless of the specific value of the angle θ between the second end wall 12121 and the axial radius R of the first pole column 12, in the embodiments of the present application, when welding the conductive portion 22 to the second end wall 12121, a second recessed groove 12122 can be installed on the second end wall 12121 as needed, and the second recessed groove 12122 is a recess formed by a local portion of the second end wall 12121 sinking into the end adjacent to the active material coated portion. The first welded portion 71 between the conductive portion 22 and the second end wall 12121 is at least partially located within the second recessed groove 12122.

[0203] In the above-described technical proposal, the portion of the conductive part 22 located within the second recessed groove 12122 is fitted in close contact with the shape of the second recessed groove 12122 to enable welding. This allows the welding position of the conductive part 22 to be pre-positioned and limited using the second recessed groove 12122, making it possible to find an appropriate position to achieve welding, which is advantageous for improving production efficiency, and also improves the stability and reliability of the electrical connection position, thereby ensuring the reliability and stability of the charging and discharging operations of the battery cell 10.

[0204] It should be explained that in the embodiment of the present application, a portion of the conductive portion 22 can be installed in accordance with the shape of the second side wall 12123 and in close contact with it. For example, if the second side wall 12123 is a curved surface, the portion of the conductive portion 22 is also a curved surface and is in close contact with the second side wall 12123. The first welded portion 71 between the conductive portion 22 and the second side wall 12123 is welded in such close contact that it extends along the second side wall 12123. This increases the area of ​​the first welded portion 71, thereby improving the reliability and stability of the weld.

[0205] Furthermore, it should be explained that in other embodiments of the present application, the first welded portion 71 between the conductive portion 22 and the second side wall 12123 does not necessarily have to extend along the second side wall 12123, but may be, for example, a plurality of discretely placed points. For example, the conductive portion 22 has a plurality of spaced locations that are welded to the second side wall 12123, but the explanation of this is omitted here.

[0206] As can be understood, there is no limit to the number of second side walls 12123, and may be determined according to the shape of the second receiving groove 12120, provided that one end of each second side wall 12123 away from the groove opening of the second receiving groove 12120 is connected to a second end wall 12121. Exemplarily, if the cross-sectional shape of the second receiving groove 12120 is circular or elliptical, the second end wall 12121 is circular or elliptical, and there is one second side wall 12123, which is formed in a ring and installed around the periphery of the second end wall 12121. Further exemplarily, if the cross-sectional shape of the second receiving groove 12120 is rectangular or racetrack-shaped, the second end wall 12121 is rectangular or racetrack-shaped, and there are four second side walls 12123, each connected to one of the four sides of the second end wall 12121.

[0207] Furthermore, it should be explained that the second accommodating groove 12120 is not limited to a configuration defined by a second end wall 12121 and a second side wall 12123. For example, in some embodiments, when Figure 17 is combined, each end of the second side wall 12123 that moves away from the groove opening of the second accommodating groove 12120 extends to the first through hole 12130. Thus, the second accommodating groove 12120 is defined solely by a plurality of second side walls 12123, in which case the conductive portion 22 can be electrically connected to the second side walls 12123.

[0208] In some embodiments, when Figure 29 is combined, the active material coated portion 21 includes a current collector 211 and an active material layer 212 provided on the current collector 211, the conductive portion 22 includes a tab portion 221 electrically connected to the current collector 211, the tab portion 221 includes a plurality of tab sheets 2211, the plurality of tab sheets 2211 gather at a position close to the current collector 211 to form a first convergence portion 2212, the plurality of tab sheets 2211 gather and connect at a position away from the current collector 211 to form a second convergence portion 2213, the first convergence portion 2212 connects the second convergence portion 2213 to the active material coated portion 21, at least a portion of the second convergence portion 2213 is housed in a second housing groove 12120, and the second convergence portion 2213 is connected to a second end wall 12121 via a first weld portion 71.

[0209] In the above proposed technology, since the tab portion 221 includes a second convergence portion 2213 formed by gathering and connecting a plurality of tab sheets 2211, it becomes relatively easy to accommodate at least a portion of the second convergence portion 2213 in the second housing groove 12120, and the assembly of the conductive portion 22 and the first pole column 12 becomes easier. Next, by accommodating at least a portion of the second convergence portion 2213 in the second housing groove 12120, the space of the first pole column 12 can be utilized, reducing the space occupied by the conductive portion 22 in the casing 11 and improving the volumetric energy density of the battery cell 10.

[0210] In some arbitrary examples, by combining Figure 29, the connection position of the first convergence section 2212 and the second convergence section 2213 can be positioned corresponding to the first through-hole 12130. In other words, in the projection plane perpendicular to the axial direction R of the first pole column 12, the orthographic projection of the connection position of the first convergence section 2212 and the second convergence section 2213 lies within the orthographic projection range of the first through-hole 12130. This allows the second convergence section 2213 to easily enter the first through-hole 12130 over a short distance and enter the second housing groove 12120, thereby reducing redundancy and costs.

[0211] As will be understood, the convergence position of the tab sheet 2211 can be related to the position of the first through hole 12130, and for example, by adopting the above-mentioned symmetrical convergence configuration or asymmetrical convergence configuration, it is possible to realize that the connection position of the first convergence part 2212 and the second convergence part 2213 is set corresponding to the first through hole 12130, but the explanation of this will be omitted here. Also, referring to the above, if the second convergence part 2213 is formed into a plate-like structure by ultrasonic tack welding, it becomes easier for the second convergence part 2213 to penetrate the first through hole 12130.

[0212] In some embodiments, when Figure 30 is combined, the active material coating portion 21 includes a current collector 211 and an active material layer 212 provided on the current collector 211, the conductive portion 22 includes a tab portion 221 and an adapter sheet 222, the tab portion 221 is electrically connected to the current collector 211, the tab portion 221 includes a plurality of tab sheets 2211, the plurality of tab sheets 2211 gather at a position close to the current collector 211 to form a first convergence portion 2212, and a plurality The tab sheet 2211 converges and connects at a position away from the current collector 211 to form a second convergence section 2213, the first convergence section 2212 connects the second convergence section 2213 to the active material coating section 21, the adapter sheet 222 is connected to the second convergence section 2213, at least a portion of the adapter sheet 222 is housed in the second housing groove 12120, and the adapter sheet 222 is connected to the second end wall 12121 via the first weld 71.

[0213] In the above proposed technology, by housing at least a portion of the adapter sheet 222 in the second housing groove 12120, the adapter sheet 222 can occupy space within the first pole column 12. This reduces the space occupied by the adapter sheet 222 within the casing 11, thereby accommodating a larger active material coating portion 21 and improving the energy density of the battery cell 10. Furthermore, it reduces the probability of a short circuit between the adapter sheet 222 and the active material coating portion 21, thereby reducing the risk of a short circuit in the battery core assembly 2, and improving the stability and reliability of the battery cell 10.

[0214] Furthermore, by using the adapter sheet 222 to achieve an indirect electrical connection between the second convergence section 2213 and the first pole column 12, the adapter sheet 222 can be welded to the first pole column 12 using the portion of the adapter sheet 222 that avoids the second convergence section 2213. This ensures a secure weld between the adapter sheet 222 and the first pole column 12, reducing the risk of welding cracks and further improving the reliability and stability of the battery cell 10. At the same time, electrically connecting the first pole column 12 and the tab sheet 2211 via the adapter sheet 222 simplifies the structure of the tab sheet 2211.

[0215] In some embodiments, when Figure 30 is combined, at least a portion of the first convergence portion 2212 is housed in the second accommodating groove 12120.

[0216] In the above proposed technology, since at least a portion of both the first convergence portion 2212 and the adapter sheet 222 are housed within the second housing groove 12120, the space of the first pole column 12 can be utilized more effectively, the space occupied by the conductive portion 22 within the casing 11 can be further reduced, and the volumetric energy density of the battery cell 10 can be further improved. In addition, by installing the sheet-structured adapter sheet 222, it becomes easier for the adapter sheet 222 to penetrate the first through-hole 12130 and extend into the second housing groove 12120.

[0217] When Figure 29 is combined, in some embodiments, the pole column body 1201 has a first housing portion 121, the first housing portion 121 has a third housing groove 12140, the surface of the first pole column 12 facing the active material coated portion 21 is the inner end face 122 of the pole column, the third housing groove 12140 is located on the side of the second housing groove 12120 that is close to the active material coated portion 21, and the opening of the third housing groove 12140 is formed on the inner end face 122 of the pole column, the third housing groove 12140 and the second housing groove 12120 are in communication via the first through hole 12130, and at least a part of the first convergence portion 2212 is housed in the third housing groove 12140.

[0218] In this case, a portion of the conductive portion 22 is located in the third housing groove 12140, and at the same time, the conductive portion 22 is also drilled in the first through hole 12130, and the remaining portion of the conductive portion 22 is located in the second housing groove 12120. As a result, the space of the first pole column 12 can be fully utilized, and the space occupied by the conductive portion 22 within the casing 11 can be reduced.

[0219] It should be explained that when the conductive part 22 is connected to the second end wall 12121 or the second side wall 12123 by laser welding, as shown in Figure 17, setting the angle β between the part of the conductive part 22 used for welding and the axis of the first through hole 12130 to be greater than 5° reduces the problem of the laser entering the casing 11 through the first through hole 12130 and is also advantageous for the welding operation. Furthermore, when the angle β between the part of the conductive part 22 used for welding and the axis of the first through hole 12130 is close to 5°, an edge welding method can be adopted, and an overlap welding method can be adopted for the other parts.

[0220] In some embodiments, when Figures 27 and 28 are combined, the casing assembly 1 further includes a second cover plate 14, which covers the first through-hole 12130 and the conductive portion 22 located within the second housing groove 12120.

[0221] It should be explained that when the casing assembly 1 includes a second cover plate 14, the casing assembly 1 may also include a first cover plate 13, or it may not include a first cover plate 13. Furthermore, when the casing assembly 1 includes both the second cover plate 14 and the first cover plate 13, the first cover plate 13 may be a composite type using multiple types of materials, or a non-composite type using the same material.

[0222] In the above proposed technology, at least a portion of the conductive portion 22 is located within the second housing groove 12120, the second cover plate 14 covers the conductive portion 22, and the second cover plate 14 further covers the first through hole 12130. This improves the problem of electrolyte overflowing from the first electrode post 12 when the electrolyte enters the second housing groove 12120 from the first through hole 12130, thereby improving the reliability of the battery cell 10.

[0223] For example, as shown in Figures 27 and 28, when a portion of the conductive part 22 is sandwiched between the second cover plate 14 and the second end wall 12121, a laser welding method can be used to weld the portion of the conductive part 22, the second cover plate 14, and the second end wall 12121 together, thereby improving the reliability of the connection between the first pole 12 and the conductive part 22. Furthermore, since the second cover plate 14 can press against the conductive part 22, the stability of the conductive part 22 being housed in the second housing groove 12120 can be improved by the second cover plate 14.

[0224] Combining Figure 13 again, in some embodiments, the casing 11 has a mounting hole 113, the first pole post 12 is mounted in the mounting hole 113, and along the axial direction of the first pole post 12, the depth H3 of the second housing groove 12120 is greater than or equal to the minimum distance H4 from the outer end face 123 of the pole post to the mounting hole 113.

[0225] It should be explained that the specific shape of the second storage groove 12120 is not particularly limited, and may be a regular or irregular shape, such as a cylindrical groove with a rectangular, elliptical, or racetrack-shaped cross-section, a trapezoidal groove with a rectangular cross-section and gradually changing cross-sectional dimensions, a hemispherical groove with a circular cross-section and gradually changing cross-sectional dimensions, or a semi-elliptical groove with an elliptical cross-section and gradually changing cross-sectional dimensions. It should be explained that the racetrack shape described herein refers to a shape obtained by combining the shapes shown in Figure 19(b), for example, by replacing the two short sides of a rectangle with convex curves.

[0226] Therefore, the depth H3 of the second housing groove 12120 refers to the maximum depth of the second housing groove 12120 along the axial R of the first pole column 12. In the axial R of the first pole column 12, the depth H3 of the second housing groove 12120 is greater than or equal to the minimum distance H4 from the outer end face 123 of the pole column to the mounting hole 113. This allows for full utilization of the volume of the first pole column 12, and the second housing groove 12120 has a relatively large depth, which is advantageous for accommodating more conductive parts 22. Furthermore, it can further reduce the space occupied by the conductive parts 22 within the casing 11, further improve the energy density of the battery cell 10, and further reduce the redundancy of the conductive parts 22 within the casing 11. At the same time, because the second housing groove 12120 has a relatively large depth, it can accommodate gas generated in the battery core assembly 2, not only ensuring the reliability and stability of the battery cell 10, but also allowing for the accommodation of more electrolyte, thus ensuring the service life of the battery cell 10.

[0227] It should be explained that the volume of the second housing groove 12120 is not limited, and for example, in some specific examples, the volume of the second housing groove 12120 (referred to as the third volume V4) that can accommodate the conductive part 22 is 298 mm². 3 The second housing groove 12120 may have a relatively sufficient space for housing the conductive part 22 and facilitate welding the conductive part 22 to the first pole column 12. On the other hand, the third volume V4 of the second housing groove 12120 is 298 mm 3 If the third volume V4 of the second housing groove 12120 is less than 300 mm³, the capacity of the second housing groove 12120 to accommodate the conductive part 22 becomes relatively low, and welding the conductive part 22 to the first pole column 12 becomes difficult. For example, if the third volume V4 of the second housing groove 12120 is 300 mm³ 3 , 400mm 3 , 500mm 3 , 600mm 3 , 700mm 3 , 800mm 3 , 1000mm 3 You can also use these.

[0228] It should be noted that the third volume V4 of the second receiving groove 12120 is the difference between the total volume V5 of the second receiving groove 12120 and the volume (denoted as the fourth volume V6) required for the second receiving groove 12120 to accommodate members other than the conductive part 22 (for example, the first cover plate 13 and the second cover plate 14 described in this specification), that is, V4 = V5 - V6. For example, in some specific examples, the total volume V5 of the second receiving groove 12120 is 1400mm 3 ~1500mm 3 Thereby, the second receiving groove 12120 can have a more sufficient space for accommodating the conductive part 22 and other members. For example, the total volume V5 of the second receiving groove 12120 is 1420mm 3 、1440mm 3 、1460mm 3 、1480mm 3 、1490mm 3 etc. may also be possible.

[0229] Optionally, when combined with FIG. 13, the second receiving groove 12120 may be installed corresponding to the position of the mounting hole 113. In other words, on the projection plane perpendicular to the axial direction R of the first pole 12, the orthographic projection of the second receiving groove 12120 is located within the orthographic projection range of the mounting hole 113, so that the second receiving groove 12120 has a relatively large depth and can accommodate more conductive parts 22. As a result, the space occupied by the conductive parts 22 in the casing 11 can be significantly reduced.

[0230] In the embodiments of the present application, there are no restrictions on the shape of the first through hole 12130, the number of the first through holes 12130, and the relative positional relationship between the first through hole 12130 and the second receiving groove 12120.

[0231] Exemplarily, regarding the shape of the first through-hole 12130, when FIGS. 18 and 19 are combined, in the embodiment of the present application, the shape of the first through-hole 12130 may be elongated so as to coincide with the sheet-like portion of the conductive part 22, which is advantageous for the sheet-like portion of the conductive part 22 to pass through. At the same time, when the first through-hole 12130 is elongated, the second accommodation groove 12120 may be configured in a shape whose cross-sectional length is greater than the width, such as a rectangle, an ellipse, a racetrack shape, etc. In this case, the length direction of the first through-hole 12130 can be installed to coincide with the length direction of the cross-section of the second accommodation groove 12120, whereby the space can be fully utilized. Also, the welding mark formed by welding the conductive part 22 and the first pole 12 may be an elongated welding mark parallel to the length direction of the first through-hole 12130 so as to improve the welding reliability and increase the current passing performance. Exemplarily, when the conductive part 22 and the second end wall 12121 are welded to form an elongated welding mark, to ensure the convenience and reliability of welding and at the same time maintain the current passing ability of the battery cell 10, the width of the welding mark is set to 6 mm or more, and the distance between the welding mark and the second side wall 12123 can be 1 mm or more.

[0232] Regarding the dimensions and number of the first through-holes 12130, in the embodiments of this application, the opening dimensions and specific positions of the first through-holes 12130 in the second housing groove 12120 are not limited, and the design can be carried out in accordance with the number of first through-holes 12130 that are opened. For example, the width of the first through-hole 12130 may be 2 mm or more, which is advantageous for the penetration of the conductive part 22. For example, if there is only one first through-hole 12130 opened in the second housing groove 12120, in some examples, combining Figures 18 and 19, the first through-hole 12130 may be positioned in the center of the second housing groove 12120, and in some other examples, combining Figure 20, the first through-hole 12130 may be positioned further offset from the center of the second housing groove 12120. For example, in some embodiments, by combining the features shown in Figure 20, the first through-hole 12130 can be opened at the edge of the second end wall 12121 so as to be located close to the second side wall 12123, thereby increasing the usable area of ​​the second end wall 12121 and increasing the welding area between the conductive portion 22 and the second end wall 12121.

[0233] As can be understood, after the conductive portion 22 passes through the first through-hole 12130, it is folded back so as to be in close contact with the second end wall 12121, but the direction of this folding is not limited. For example, if the first through-hole 12130 is centrally located relative to the second housing groove 12120, the conductive portion 22 can be folded back to face either side of the first through-hole 12130 after passing through it (combining Figure 18), thereby appropriately reducing the dimensions of the second housing groove 12120 and increasing the compactness and structural strength of the structure. Alternatively, the conductive portion 22 can be folded back to face the opposite side after passing through the first through-hole 12130 (combining Figure 21), thereby reducing the thickness of the welded area, reducing the heat input of the weld, and reducing problems such as particle scattering.

[0234] For example, if there are multiple first through-holes 12130 in the second housing groove 12120, the multiple first through-holes 12130 are arranged parallel or nearly parallel in their longitudinal direction so that the space can be fully utilized. In this case, the direction in which the conductive part 22 folds back after passing through the first through-hole 12130 can be set based on the relative positional relationship of the multiple first through-holes 12130. For example, if there are two first through-holes 12130 in the second housing groove 12120 and they are far apart from each other (see Figure 22), the two conductive parts 22 passing through the two first through-holes 12130 can fold back in a direction that brings them closer to each other, and if there are two first through-holes 12130 in the second housing groove 12120 and they are close to each other, the two conductive parts 22 passing through the two first through-holes 12130 can fold back in a direction that moves them away from each other.

[0235] As can be understood, if there are multiple first through holes 12130 opened in the second receiving groove 12120, the number of first pole posts 12 can be appropriately reduced, thereby reducing costs and simplifying the process.

[0236] Furthermore, in some embodiments, by combining Figures 20 and 21, the first through-hole 12130 can be positioned in the center relative to the active material coated section 21. However, the position of the first through-hole 12130 relative to the second accommodating groove 12120 is not limited; it may be in the center or offset. Since the first through-hole 12130 is positioned in the center relative to the active material coated section 21, the conductive section 22 can converge to correspond to the centerline position of the active material coated section 21.

[0237] In some embodiments, by combining Figure 21, a sealing member 6 can be installed in the first through-hole 12130 to improve the problem of electrolyte leakage from the casing 11 through the first through-hole 12130. The material, shape, and method of connection to the first through-hole 12130 of the sealing member 6 are not limited, but exemplary, the sealing member 6 may be a metal member made of the same material as the first pole 12 and conductive part 22, and may be welded to the wall surface of the first through-hole 12130 of the first pole 12 to seal the first through-hole 12130. Also exemplary, the sealing member 6 may be a plastic member, and may be swivel-fitted into the first through-hole 12130 to seal the first through-hole 12130. In embodiments of the present application, any of these can be designed according to the actual requirements without limitation.

[0238] Figure 23 is an exploded view of the configuration of a battery cell 10 provided in some embodiments of the present application, Figure 24 is a schematic local cross-sectional view of a casing assembly 1 provided in some embodiments of the present application, and Figure 25 is an exploded view of the configuration of the casing assembly 1 shown in Figure 24. Combining Figures 23 and 24, in some embodiments of the present application, if the housing portion 121 has a second housing groove 12120 of any of the embodiments, the casing assembly 1 may optionally further include a first cover plate 13 that fits with a first pole post 12 and seals the groove opening of the second housing groove 12120, the first cover plate 13 being electrically connected to the first pole post 12.

[0239] In the above proposed technology, by installing the first cover plate 13 so as to seal the groove opening of the second housing groove 12120, leakage of the electrolyte from the casing 11 through the groove opening of the second housing groove 12120 can be prevented. Furthermore, since the first cover plate 13 seals the groove opening of the second housing groove 12120 and is electrically connected to the first pole column 12, an indirect electrical connection between the first pole column 12 and the bus member can be easily realized using the first cover plate 13, and this is advantageous in increasing the connection area of ​​the electrical connection point and further reducing the resistance of the electrical connection point.

[0240] As long as the first cover plate 13 can be sealed to the groove opening of the second housing groove 12120, the fitting method and fitting position of the first cover plate 13 and the first pole post 12 are not limited. For example, in some embodiments, when Figure 22 is combined, the first cover plate 13 may be welded to the first pole post 12, and during processing, the conductive part 22 can first pass through the first through hole 12130 and be welded to the groove wall of the second housing groove 12120, and then the first cover plate 13 and the first pole post 12 can be welded together to seal the groove opening of the second housing groove 12120.

[0241] When Figure 31 is combined, in several embodiments, the pole column body 1201 is provided with a first housing section 121, the first housing section 121 has a fourth housing groove 12150, the fourth housing groove 12150 is a groove-shaped tank with a certain depth, the surface of the pole column body 1201 away from the active material coated section 21 is the pole column outer end surface 123, the groove opening of the fourth housing groove 12150 is formed on the pole column outer end surface 123, and the fourth housing groove 121 50 communicates with the inside of the casing 11 through the second through hole 12160, and the conductive part 22 does not necessarily have to be housed in the fourth housing groove 12150; for example, the conductive part 22 may be drilled in the second through hole 12160, the first welded part 71 is provided on the hole wall of the second through hole 12160 formed in the first housing part 121, and the first cover plate 13 fits with the pole column body 1201 and seals the second through hole 12160.

[0242] In the above embodiment, by installing the fourth housing groove 12150, welding between the conductive part 22 and the hole wall of the second through hole 12160 can be easily achieved. In addition, in some cases, sealing of the second through hole 12160 can be achieved by utilizing the welding between the conductive part 22 and the first pole column 12. For example, by welding the conductive part 22 and the hole wall of the second through hole 12160 at the position where the second through hole 12160 and the fourth housing groove 12150 are connected, the operation can be made easier, and by controlling the weld marks, sealing of the second through hole 12160 can be achieved using the weld marks and the conductive part 22, thereby improving the problem of electrolyte leakage from the casing 11 through the second through hole 12160.

[0243] It should be noted that the specific shape of the fourth storage groove 12150 is not limited, and may be a regular or irregular shape, such as a cylindrical groove with a rectangular, elliptical, or racetrack-shaped cross-section, a trapezoidal groove with a rectangular cross-section and gradually changing cross-sectional dimensions, a hemispherical groove with a circular cross-section and gradually changing cross-sectional dimensions, or a semi-elliptical groove with an elliptical cross-section and gradually changing cross-sectional dimensions.

[0244] In the embodiment of the present application, the shape of the second through-hole 12160 may be elongated to conform to the sheet-like local shape of the conductive portion 22, which is advantageous for penetrating the sheet-like local portion of the conductive portion 22. At the same time, if the second through-hole 12160 is elongated, the fourth accommodating groove 12150 may be configured to have a cross-sectional length greater than its width, such as a rectangle, ellipse, or racetrack shape. In this case, the length direction of the second through-hole 12160 can be aligned with the cross-sectional length direction of the fourth accommodating groove 12150, thereby allowing for full utilization of the space.

[0245] It should be noted that the first housing portion 121 in the embodiments of the present application is not limited to the above-described form in which it must have at least one housing groove. For example, in some other embodiments of the present application, when combined with Figure 32, the first housing portion 121 may have only a third through hole 12170, the surface of the first pole column 12 facing the active material coated portion 21 is the inner end face 122 of the pole column, the surface of the first pole column 12 away from the active material coated portion 21 is the outer end face 123 of the pole column, the third through hole 12170 is in the form of a through hole and penetrates the inner end face 122 and the outer end face 123 of the pole column, and at least a portion of the conductive portion 22 is drilled in the third through hole 12170. The electrical connection position between the conductive portion 22 and the first pole column 12 is not limited. For example, the electrical connection position may be located at the hole wall where the third through-hole 12170 of the first pole column 12 is formed, or the conductive portion 22 may penetrate the third through-hole 12170 such that the electrical connection position is located on the outer end face 123 of the pole column outside the third through-hole 12170. Furthermore, the shape of the third through-hole 12170 is not limited. It may be a regularly shaped hole with equal cross-sections, or a hole with an irregular cross-sectional shape with unequal cross-sections. Moreover, the cross-sectional shape of the third through-hole 12170 is not limited. It may be elongated, such as rectangular, elliptical, or racetrack-shaped, to match the sheet-like local shape of the conductive portion 22. This is advantageous for the sheet-like local portion of the conductive portion 22 to be drilled into the third through-hole 12170, and further explanation is omitted here.

[0246] In the embodiments of the present application, the first pole column 12 may be an integrally molded pole column or a separately molded composite pole column. Combining Figures 27 and 28, in some embodiments, the pole column body 1201 includes a first pole column portion 124 and a second pole column portion 125 made of different materials and electrically connected, the second pole column portion 125 being located on the side of the first pole column portion 124 away from the active material coated portion 21, the first housing portion 121 being installed on the first pole column portion 124 or on the first pole column portion 124 and the second pole column portion 125, and the first weld portion 71 being provided on the first pole column portion 124.

[0247] In the above proposed technology, the first pole column 12 is installed in a composite form made of a combination of different materials, and the first pole column portion 124 located on the inside is housed and fitted into the conductive portion 22 and electrically connected, while the second pole column portion 125 located on the outside is electrically connected to the bus member 30, etc. This is advantageous for assembling and electrically connecting the first pole column 12 with related parts, reducing mutual interference between the welding position of the first pole column 12 and the conductive portion 22, and between the welding position of the first pole column 12 and the bus member 30 of the battery 100, thereby improving the reliability and stability of the battery cell 10.

[0248] For example, if the material of the conductive part 22 is different from the material of the bus member 30, installing the first pole column 124 from the same material as the conductive part 22 and the second pole column 125 from the same material as the bus member 30 is advantageous for welding the second pole column 125 to the bus member 30 and the first pole column 124 to the conductive part 22, thereby improving the reliability and stability of the electrical connection between the conductive part 22 and the first pole column 12, and improving the reliability and stability of the electrical connection between the first pole column 12 and the bus member 30.

[0249] Furthermore, if the first pole column 12 is a composite form of the above embodiment and has the second housing groove 12120 and the first through hole 12130 of any of the above embodiments, in some embodiments the casing assembly 1 may simultaneously include the second cover plate 14 of any of the above embodiments, in which case the second cover plate 14 may be installed to be made of the same material as the first pole column portion 124, and the first pole column portion 124 and the second cover plate 14 may be electrically connected, thereby improving the reliability and stability of the electrical connection between the first pole column portion 124 and the second cover plate 14. For example, the first pole column portion 124 and the second cover plate 14 may be connected by welding.

[0250] For example, when FIGS. 27 to 28 are combined, if the first pole 12 is a negative pole, the first pole part 124 is made of copper, the second pole part 125 is made of aluminum, and the bus member 30 is an aluminum sheet, the second cover plate 14 can be installed on copper and the first cover plate 13 can be installed on aluminum. In this case, the second cover plate 14 and the first pole part 124 can be effectively welded with the same material, the second pole part 125 and the first cover plate 13 can be effectively welded with the same material, and the first cover plate 13 and the bus member 30 can be effectively welded with the same material.

[0251] In the embodiment of the present application, when the first accommodating part 121 has the second accommodating groove 12120, the fitting situation between the battery core assembly 2 and the second accommodating groove 12120 is not limited by the configuration of the battery core assembly 2. For example, it includes but is not limited to the following two examples of the third embodiment and the fourth embodiment.

[0252] In some embodiments, when FIGS. 8 and 54 are combined, the second accommodating part 134 is installed on the first cover plate 13. The second accommodating part 134 has the fifth accommodating groove 1341. The groove opening of the fifth accommodating groove 1341 is formed on the end face of the end towards the active material coating part 12 of the first cover plate 13. And the fifth accommodating groove 1341 has the third end wall 13411 and the third side wall 13412. The third end wall 13411 is located on the side away from the active material coating part 21 of the third side wall 13412. At least a part of the first welding part 71 is accommodated in the fifth accommodating groove 1341.

[0253] Exemplarily, when no accommodating groove is formed on the outer end face 123 of the pole of the first pole 12, the outer end face 123 of the pole is a flat surface. In this case, the first welding part 71 protrudes from the outer end face 123 of the pole. By installing the fifth accommodating groove 1341 on the first cover plate 13, the first welding part 71 is accommodated to protect the connection between the first welding part 71 and the subsequent bus member.

[0254] Of course, if the pole column body 1201 has a second accommodating groove 12120, and the groove opening of the second accommodating groove 12120 is formed on the outer end face 123 of the pole column, then a fifth accommodating groove 1341 can also be installed in the first cover plate 13, and by fitting with the second accommodating groove 12120 to accommodate the first welded portion 71, the first welded portion 71 and the subsequent connection with the bus member are protected.

[0255] In the above proposed technology, by installing a fifth housing groove 1341 in the first cover plate 13, the weight of the first pole column 12 can be reduced to some extent, thereby improving the gravimetric energy density of the battery cell 10 and the battery 100. At the same time, since the groove opening of the fifth housing groove 1341 is formed on the end face of the end of the first cover plate 13 facing the active material coated portion 12, and the third end wall 13411 is located on the side of the third side wall 13412 away from the active material coated portion 21, the fifth housing groove 1341 can be opened facing away from the active material coated portion 21. Thus, by housing at least a part of the conductive portion 22 in the fifth housing groove 1341, the first welded portion 71 can be easily housed and arranged through the groove opening of the fifth housing groove 1341, thereby reducing the difficulty of producing the battery cell 10 and improving the production efficiency of the battery cell 10.

[0256] In some embodiments, the first cover plate 13 is electrically connected to the pole body 1201, or it is installed insulated from the pole body 1201. In other words, the first cover plate 13 can be electrically connected to the pole body 1201, in which case it can also be involved in the electrical connection of the bus member 30, thereby increasing the area of ​​the weldable region and facilitating welding between the first pole 12 and the bus member 30. The first cover plate 13 does not have to be electrically connected to the pole body 1201, i.e., the two are insulated from each other, in which case the first cover plate 13 mainly serves to protect the first weld 71.

[0257] In some embodiments, as shown in Figure 26, the first cover plate 13 includes a first conductive member 131 and a second conductive member 132 made of different materials, the first conductive member 131 being fitted to and electrically connected to the pole column body 1201, and the second conductive member 132 being fitted to and electrically connected to the first conductive member 131.

[0258] In the above proposed technology, by installing the first cover plate 13 in a composite form and installing the first conductive member 131 so as to be made of the same material as the first pole post 12, the electrical connection between the first conductive member 131 and the first pole post 12 is facilitated, and for example, the first conductive member 131 and the first pole post 12 can be reliably and stably connected by welding. Furthermore, because the second conductive member 132 and the first conductive member 131 are made of different materials, the second conductive member 132 can be used to easily electrically connect to bus members and the like that which are made of different materials than the first pole post 12, and for example, the second conductive member 132 and bus members made of the same material as the second conductive member 132 can be reliably and stably connected by welding.

[0259] For example, if the first pole column 12 is a negative pole column, and the first pole column 12 is a copper column and the bus member is an aluminum sheet, the first conductive member 131 can be installed on the copper material and the second conductive member 132 can be installed on the aluminum material. In this case, the first pole column 12 and the first conductive member 131 may be made of the same material and effectively welded together, and the second conductive member 132 and the bus member may be made of the same material and effectively welded together. This allows for effective indirect electrical connection between the first pole column 12 and the bus member via the first cover plate 13. Furthermore, the first pole column 12 and the first conductive member 131 are welded copper to copper, which provides excellent fluidity, reduces the likelihood of cracking, and improves the sealing effect of the welded area.

[0260] The method of fitting the first conductive member 131 and the second conductive member 132 is not limited to what needs to be explained. In some embodiments, when Figures 24 to 26 are combined, the first conductive member 131 has a second groove 1311, the second conductive member 132 is fitted into the second groove 1311, and the opening of the second groove 1311 is formed on the surface of the first conductive member 131 away from the active material coated portion 21 such that the second conductive member 132 is exposed from the opening of the second groove 1311. Alternatively, in other embodiments, the method of connecting the first conductive member 131 and the second conductive member 132 may be fastening, engagement, etc.

[0261] Furthermore, it should be explained that the second conductive member 132 being "exposed" from the groove opening of the second groove 1311 means that the first conductive member 131 does not obstruct the second conductive member 132 at the groove opening position of the second groove 1311, and the second conductive member 132 does not need to protrude from the groove opening of the second groove 1311. For example, the second conductive member 132 may be positioned flush with the surface of the first conductive member 131 on the side away from the second housing groove 12120, or the second conductive member 132 may protrude from the surface of the first conductive member 131 on the side away from the second housing groove 12120.

[0262] In the above proposed technology, by fitting the second conductive member 132 into the first conductive member 131, the difficulty of assembling the first conductive member 131 and the second conductive member 132 can be reduced, improving the fitting stability and convenience of the first conductive member 131 and the second conductive member 132. Furthermore, the thickness of the first cover plate 13 can be reduced, decreasing the space occupied by the first cover plate 13 and improving the space utilization rate of the battery cell 10. On the other hand, since the second conductive member 132 can be exposed from the surface of the first conductive member 131 away from the second housing groove 12120 through the groove opening of the second recess 1311, it is advantageous for realizing an electrical connection between the second conductive member 132 and the bus member outside the first pole column 12.

[0263] Furthermore, since the groove opening of the second groove 1311 is formed on the surface of the first conductive member 131 that is separated from the second housing groove 12120, it is suggested that the second groove 1311 opens in a direction away from the active material coated portion 21. For this reason, a portion defining the groove wall of the second groove 1311 of the first conductive member 131 is located between the second housing groove 12120 and the second conductive member 132. This separates the second housing groove 12120 and the second conductive member 132, preventing contact between the electrolyte that has entered the second groove 1311 and the second conductive member 132, and reducing electrolyte leakage.

[0264] Of course, in other embodiments, the first cover plate 13 does not have to be a composite form made of multiple materials. For example, in other embodiments of the present application, when combined with Figure 27, the first cover plate 13 can be installed in a non-composite form made of the same material as a whole, for example, to fit the positive pole, but such a description will be omitted here.

[0265] Combining Figures 24 to 26 again, in some embodiments, the first cover plate 13 is also fitted into the groove of the second housing groove 12120. In the above technical proposal, by fitting the first cover plate 13 into the second housing groove 12120, the difficulty of assembling the first cover plate 13 and the first pole post 12 can be reduced, the assembly stability, connection reliability and convenience of the first cover plate 13 and the first pole post 12 can be improved, and the space occupied by the first cover plate 13 other than the first pole post 12 can be reduced. Furthermore, since the first cover plate 13 is fitted into the groove of the second housing groove 12120, there can be a relatively sufficient space within the second housing groove 12120 to accommodate the conductive part 22.

[0266] Of course, in other embodiments of the present invention, the method of fitting the first cover plate 13 and the first pole post 12 is not limited to fitting them into the second housing groove 12120. The first cover plate 13 may also be placed outside the first pole post 12. That is, to facilitate fitting with the bus member of the battery 100, it may be directly covered at the groove opening of the second housing groove 12120, and this embodiment is not limited to this.

[0267] Combining Figures 24 to 26 again, selectively, in the embodiment of the present invention, at least a portion of the wall surface forming the groove opening of the second housing groove 12120 in the first pole column 12 is a guide slope 12126, and the guide slope 12126 is used to guide the first cover plate 13 to fit into the groove opening of the second housing groove 12120. In the above technical invention, by processing the wall surface of the groove opening of the second housing groove 12120 into a slope with a guiding function, the difficulty of assembling the first cover plate 13 and the second housing groove 12120 can be reduced, and the assembly efficiency of the first cover plate 13 and the second housing groove 12120 can be improved. Furthermore, when the first cover plate 13 is welded to the guide slope 12126, the area of ​​the weld can be increased, improving the reliability of the welded connection between the first cover plate 13 and the first pole column 12, and also improving the problem of the molten pool collapsing or the laser entering the first pole column 12 during welding.

[0268] Specifically, when Figures 24 to 26 are combined, the second housing groove 12120 includes the first groove step 12124 and the second groove step 12125 located on the side of the first groove step 12124 that is close to the outer end surface 123 of the pole column. Since the cross-sectional area of ​​the second groove step 12125 is larger than the cross-sectional area of ​​the first groove step 12124, by making the second housing groove 12120 a stepped groove and forming the connection position between the first groove step 12124 and the second groove step 12125 on a stepped surface 12127, when the first cover plate 13 is fitted into the second housing groove 12120, it is specifically fitted into the second groove step 12125 and supported by the stepped surface 12127.

[0269] In the above proposed technology, by installing the second housing groove 12120 in a stepped groove form, the first cover plate 13 can be stably fitted into the groove opening position of the second housing groove 12120, thereby improving the connection stability between the first cover plate 13 and the first pole column 12. Furthermore, by limiting the groove depth of the first groove step 12124, a relatively sufficient space can be provided within the second housing groove 12120 for housing the conductive part 22.

[0270] Furthermore, if the wall surface where the groove opening of the second housing groove 12120 of the first pole column 12 is formed is a guide slope 12126, the cross-sectional area of ​​the second groove step 12125 is set to gradually increase along the direction approaching the outer end surface 123 of the pole column, so that the side wall of the second groove step 12125 forms the guide slope 12126, thereby facilitating processing and easily and effectively satisfying the requirements for a guide.

[0271] Combining Figures 24 to 26 again, in some embodiments, the first cover plate 13 has stress relaxation grooves 133, and the stress relaxation grooves 133 are located in the outer peripheral region of the first cover plate 13 in order to assist in stress relaxation of the first cover plate 13.

[0272] In the above proposed technology, stress relief grooves 133 are installed in the first cover plate 13 to release stress generated during the manufacturing process of the first cover plate 13 itself, or during the electrical connection process between the first cover plate 13 and the first pole column 12, in order to improve related problems such as deformation and damage caused by stress on the first cover plate 13.

[0273] Specifically, when the first cover plate 13 is fitted into the second housing groove 12120 and welded, the stress relief groove 133 releases the stress generated during welding, improves lateral heat conduction, and reduces the probability of the first cover plate 13 being damaged or deformed. At the same time, if the first cover plate 13 is a composite form including the first conductive member 131 and the second conductive member 132, by installing the stress relief groove 133 on the first conductive member 131 and positioning it in the outer peripheral region of the second conductive member 132, when the first conductive member 131 is fitted into the second housing groove 12120 and welded, the stress relief groove 133 releases the stress generated during welding, improves lateral heat conduction, and reduces the probability of the second conductive member 132 being damaged or deformed. Furthermore, when the second conductive member 132 and the first conductive member 131 are fitted together and welded, the stress relief groove 133 releases the stress generated during welding, improving lateral heat conduction and reducing the probability of deformation of the first conductive member 131 or the inability to fit the first conductive member 131 into the second housing groove 12120.

[0274] Combining Figures 27 and 28, in the embodiment of the present invention, a second cover plate 14 may be installed in the casing assembly 1 as needed, and the second cover plate 14 covers the outside of the conductive portion 22 located in the first through hole 12130 and the second housing groove 12120.

[0275] It should be explained that when the casing assembly 1 includes a second cover plate 14, the casing assembly 1 may also include a first cover plate 13, or it may not include a first cover plate 13. Furthermore, when the casing assembly 1 includes both the second cover plate 14 and the first cover plate 13, the first cover plate 13 may be a composite type using multiple types of materials, or a non-composite type using the same material.

[0276] In the above proposed technology, at least a portion of the conductive portion 22 is located within the second housing groove 12120, the second cover plate 14 covers the conductive portion 22, and the second cover plate 14 further covers the first through hole 12130. This improves the problem of electrolyte overflowing from the first electrode post 12 when the electrolyte enters the second housing groove 12120 from the first through hole 12130, thereby improving the reliability of the battery cell 10.

[0277] For example, as shown in Figures 27 and 28, when a portion of the conductive part 22 is sandwiched between the second cover plate 14 and the second end wall 12121, a laser welding method can be used to weld the portion of the conductive part 22, the second cover plate 14, and the second end wall 12121 together, thereby improving the reliability of the connection between the first pole 12 and the conductive part 22. Furthermore, since the second cover plate 14 can press against the conductive part 22, the stability of the conductive part 22 being housed in the second housing groove 12120 can be improved by the second cover plate 14.

[0278] Combining Figures 33 to 35, in some embodiments, the battery cell 10 further includes a support 3 located within the casing 11 and adjacent to the first pole column 12 of the active material coated portion 21, the support 3 having a relief hole 31 to avoid the conductive portion 22, the conductive portion 22 being adapted to extend through the relief hole 31 toward the side of the support 3 away from the active material coated portion 21, thereby ensuring that the battery cell 10 can be welded to the first pole column 12 and that charging and discharging operations can be performed normally.

[0279] In the above proposed technology, by installing the support 3 on the side of the active material coated section 21 that is close to the first pole column 12, the support 3 can be used to separate the active material coated section 21 from the casing 11, thereby improving the reliability of the battery cell 10. Furthermore, by providing a relief hole 31 in the support 3, the conductive section 22 can be guided and restrained to penetrate the relief hole 31 and engage with the first pole column 12. This eliminates the need to route the conductive section 22 away from the edge of the support 3 to approach the first pole column 12, further simplifying the arrangement of the conductive section 22, saving material for the conductive section 22, and reducing costs. In addition, the support 3 can support and guide the engagement between the conductive section 22 and the first pole column 12, reducing the risk of short-circuit connection between the conductive section 22 and the active material coated section 21, and further improving the reliability of the battery cell 10.

[0280] In some embodiments, the pole column body 1201 is provided with a first housing section 121, and the support 3 is provided with a guide section 32, the guide section 32 surrounds and forms at least a part of the escape hole 31, and the guide section 32 extends at least partially to the first housing section 121.

[0281] It should be explained that the guide portion 32 protrudes from the support 3 and enters the first housing portion 121, and at least a part of the relief hole 31 is formed within the guide portion 32. Therefore, when the conductive portion 22 is drilled in the relief hole 31, at least a part of the conductive portion 22 can be easily housed within the first housing portion 121, improving the assembly efficiency of the conductive portion 22. At the same time, the installation of the guide portion 32 results in tighter and more reliable fitting between the support 3 and the first pole column 12, and between the support 3 and the conductive portion 22. This makes the structure of the battery cell 10 more compact and is advantageous for improving the energy density of the battery cell 10.

[0282] By combining Figures 33 to 35, a third groove 38 is selectively provided in the support 3, and at least a portion of the first pole column 12 located inside the casing 11 is housed in the third groove 38.

[0283] In the above proposed technology, by installing a third groove 38 in the support 3 and housing at least a portion of the first pole column 12 located inside the casing 11 within the third groove 38 of the support 3, the compactness of the structure can be improved, which is advantageous in reducing the space occupied by the support 3 within the casing 11, while also improving the stability and reliability of the first pole column 12. This ensures the reliability and stability of the electrical connection between the first pole column 12 and the battery core assembly 2, thereby improving the reliability and stability of the charging and discharging operations of the battery cell 10.

[0284] Furthermore, in some embodiments, the guide portion 32 can be involved in defining the third groove 38, thereby simplifying the structure of the support 3, reducing the difficulty of designing and manufacturing the support 3, and is advantageous for increasing the wall thickness of the guide portion 32 and improving the guiding reliability of the guide portion 32. It is also advantageous for improving the stability and reliability of the first pole column 12, thereby ensuring the reliability and stability of the electrical connection between the first pole column 12 and the battery core assembly 2, and improving the reliability and stability of the charging and discharging operations of the battery cell 10.

[0285] Combining Figures 33 to 35, in some embodiments, the relief hole 31 includes a first hole step 311 and a second hole step 312, the second hole step 312 is located on the side of the first hole step 311 that is close to the active material coated portion 21, and the cross-sectional area of ​​the second hole step 312 gradually increases in the direction away from the first hole step 311, the active material coated portion 21 includes a current collector 211 and an active material layer 212 provided on the current collector 211, and the conductive portion 22 includes a tab portion 221 that is electrically connected to the current collector 211, and the tab portion 22 1 includes a plurality of tab sheets 2211, the plurality of tab sheets 2211 are gathered in a position close to the current collector 211 to form a first convergence portion 2212, the plurality of tab sheets 2211 are gathered and connected in a position away from the current collector 211 to form a second convergence portion 2213, the first convergence portion 2212 connects the second convergence portion 2213 to the active material coating portion 21, at least a portion of the first convergence portion 2212 is housed in a second hole step 312, and the second convergence portion 2213 is drilled in the first hole step 311.

[0286] In the above-described technical proposal, by arranging the relief hole 31 to include a second hole step 312 that gradually widens toward the active material coated portion 21, it is possible to accommodate more first convergence portions 2212 in the second hole step 312, improving the compactness of the fitting between the support 3 and the battery core assembly 2, reducing the overall volume of the battery cell 10, allowing more battery cells 10 to be accommodated in the battery 100, and improving the volumetric energy density of the battery 100. Furthermore, in the above-described technical proposal, a detailed explanation of the first convergence portion 2212 and the second convergence portion 2213 has already been described in the above-described embodiment, and will be omitted here.

[0287] In some embodiments, support 3 is a single integrated structure, or, as shown in Figure 36, support 3 is a separate structure including a removable first support 33 and a second support 34, with a relief hole 31 defined between the first support 33 and the second support 34.

[0288] In the above proposed technology, the relief hole 31 is formed as a through-hole that penetrates the support 3. Therefore, the integral structure of the support 3 is easy to process, has relatively high reliability, and assembly of the support 3 with the casing assembly 1 is also easy, improving assembly efficiency and fitting stability. As can be seen, how to process the support 3 can be specifically selected depending on the material of the support 3. For example, if the support 3 is an insulating plastic member, an integral structure of the support 3 can be obtained by injection molding.

[0289] When Figure 37 is combined, if support 3 is a separate structure, support 3 includes a removable first support 33 and a second support 34, both of which are elongated plate-like structures and can be detachably connected, for example, they can be fitted together by insertion or engagement, making assembly easy. Furthermore, the first support 33 has a semi-perforated structure on the side adjacent to the second support 34, and another semi-perforated structure of a suitable shape is provided on the side of the second support 34 adjacent to the first support 33, and the semi-perforated structures of the first support 33 and the second support 34 together surround each other to form an annular relief hole 31. That is, a relief hole 31 is defined between the first support 33 and the second support 34.

[0290] In the above proposed technology, the relief hole 31 is defined by the fitting of the first support 33 and the second support 34. When assembling the support 3 and the battery core assembly 2, it is not necessary to pass the conductive part 22 from one end of the relief hole 31 to the other. Instead, the first support 33 and the second support 34 can be combined at the position of the conductive part 22 to sandwich the conductive part 22, and the relief hole 31 surrounds the conductive part 22. This makes the assembly of the support 3 and the battery core assembly 2 easier and improves assembly efficiency.

[0291] As an alternative technical option, if the cross-section of the relief hole 31 is elongated, the first support 33 and the second support 34 are positioned on both sides of the relief hole 31 in the width direction. For example, if the width direction of the relief hole 31 is left-right, the first support 33 and the second support 34 are located on the left and right sides of the relief hole 31, thereby facilitating the fitting of the first support 33 and the second support 34 with the conductive part 22.

[0292] Combining Figures 33, 38, and 39, the configuration of the support 3 in the embodiment of the present application is not limited thereto. For example, a casing-enclosed guide surface 35 may be installed on the edge of the support 3. The mounting guide surface 35 to the casing may be inclined or curved, and it is orthogonal projected along the axial radius R of the first pole column 12. The orthogonal projection of the active material coated portion 21 is entirely located within the orthogonal projection range of the support 3, and the orthogonal projection range of the support 3 exceeds the orthogonal projection range of the active material coated portion 21. During assembly, the support 3 and battery core assembly 2 can be pre-assembled. This pre-assembled assembly is then attached to the casing 11. During attachment, the support 3 is positioned at the front end of the active material coating section 21, meaning the support 3 enters the casing 11 before the active material coating section 21. This reduces the difficulty of the support 3 entering the casing 11 using the casing entry guide surface 35. Furthermore, the relatively large projected area of ​​the support 3 provides protection for the active material coating section 21, reducing the probability of scratches between the active material coating section 21 and the casing 11, thereby improving assembly efficiency and success rate. Additionally, the contact area between the support 3 and the active material coating section 21 can be increased, mitigating stress concentration problems and allowing for the omission of other structural components.

[0293] When Figure 38 is combined, in some embodiments of the present invention, the battery cell 10 further includes an inner insulating member 4, the inner insulating member 4 is located inside the casing 11 and includes the outside of the active material coated portion 21, and the inner insulating member 4 is connected to a support 3. In the above embodiments, by enclosing the outside of the active material coated portion 21 with the inner insulating member 4, the insulation reliability between the active material coated portion 21 and the casing 11 is improved, corrosion of the casing 11 due to contact between the active material coated portion 21 and the casing 11 is reduced or prevented, the problem of electrolyte leakage due to corrosion of the casing 11 is reduced, and the reliability of the battery cell 10 is improved. On the other hand, by connecting the inner insulating member 4 to the support 3, the difficulty of fixing the inner insulating member 4 is reduced and the reliability of the inner insulating member 4 enclosing the outside of the active material coated portion 21 is improved.

[0294] When combined with Figure 38, in the embodiment of the present application, the support 3 includes a main body portion 36 and an extension portion 37, the main body portion 36 is located on the side of the active material coated portion 21 that is close to the first pole column 12, and the extension portion 37 is connected to the main body portion 36 and located in the outer peripheral region of the active material coated portion 21. For example, the extension portion 37 may be connected to the periphery of the main body portion 36 to form an annular extension structure connected to the main body portion 36, or it may extend from a local part in the circumferential direction of the main body portion 36 and form a block structure that protrudes from the main body portion 36. On the other hand, the installation of the extension portion 37 allows the active material coated portion 21 to be fitted in a position-restrictive manner, improving the problem of toner falling off from the edge of the active material coated portion 21 and corroding the casing 11 by overlapping with it. On the other hand, the installation of the extension portion 37 also allows the inner insulating member 4 to be fixed, improving the reliability of the connection between the inner insulating member 4 and the support 3, and providing a relatively good insulating effect.

[0295] For example, when Figure 38 is combined, the main body 36 and the extension 37 can define a positioning groove 39 located on the side of the extension 37 away from the active material coated portion 21. The end of the inner insulating member 4 is fitted into the positioning groove 39, preventing the inner insulating member 4 from protruding from the edge of the main body 36. This protects the inner insulating member 4 with the main body 36 when it is attached to the casing, reducing the probability of scratches between the inner insulating member 4 and the casing 11.

[0296] Specifically, when Figure 39 is combined, the inner insulating member 4 may be an integral film having main body portions 41 located on both sides in the thickness direction of the active material coated portion 21 and connecting portions 42 connecting the two main body portions 41. The connecting portions 42 are located on the side of the active material coated portion 21 away from the first pole column 12, and the edge of the main body portion 41 away from the connecting portions 42 extends to the extended portion 37 and is connected to the extended portion 37. This provides relatively good insulating performance and facilitates connection.

[0297] In the embodiments of this application, the specific method for installing the first pole column 12 in the casing 11 is not limited and may include, for example, riveting or welding, which will be described below.

[0298] In some embodiments, when Figures 56 and 57 are combined, the casing 11 has a first wall 110, a mounting hole 113 is formed in the first wall 110, the pole column body 1201 is installed in the mounting hole 113, the plane on which the cross-section of the mounting hole 113 is located is the projection plane, and along the direction perpendicular to the projection plane, the ratio of the projected area of ​​the first welded part 71 to the projected area of ​​the first wall 110 on the projection plane is in the range of 0.1% to 1%.

[0299] The cross-section of the mounting hole 113 is perpendicular to the axial direction of the mounting hole 113 (third direction Z), and if the projection direction under the above conditions is parallel to the axial direction of the mounting hole 113, then the orthogonal projected area of ​​the first weld 71 is understood to be the orthogonal projected area of ​​the connection region between the conductive part 22 and the pole column body 1201 in the cross-section of the mounting hole 113. Thus, the orthogonal projected area of ​​the first weld 71 in the cross-section of the mounting hole 113 reflects the size of the area of ​​the connection region between the conductive part 22 and the pole column body 1201. If the orthographic projection area of ​​the first welded portion 71 in the cross-section of the mounting hole 113 satisfies the above conditions, the equivalent resistance between the conductive portion 22 and the pole column body 1201 can be reduced to some extent, improving the current passage area of ​​the first pole column 12 and improving the current passage capability of the first pole column 12. This is advantageous for improving the charging speed of the battery cell 10 and improving the rapid charging performance of the battery cell 10, and at the same time, to some extent, is also advantageous for improving the heat dissipation capability of the first pole column 12.

[0300] In the above proposed technology, by setting the ratio of the projected area of ​​the first welded portion 71 on the projection surface to the projected area of ​​the first wall 110 on the projection surface to be in the range of 0.1% to 1%, the effective current passage area between the conductive portion 22 and the pole column body 1201 is improved, the current passage area of ​​the first pole column 12 is improved, and the current passage capability of the first pole column 12 is improved. This is advantageous for improving the charging speed of the battery cell 10, and at the same time, to some extent, is also advantageous for improving the heat diffusion capability of the first pole column 12, which reduces the current passage temperature of the first pole column 12 and is advantageous for reducing the risk of runaway operation of the battery cell 10.

[0301] In some embodiments, when Figure 57 is combined, the casing 11 has a mounting hole 113, and the pole post body 1201 includes an integrally molded pole post main body 12a, a first position limiting base 12b, and a second position limiting base 12c, the pole post main body 12a being drilled in the mounting hole 113 of the casing 11, the first position limiting base 12b and the second position limiting base 12c being installed at both ends of the pole post main body 12a along the axial direction of the mounting hole 113, the first position limiting base 12b being positionally fitted to the outside of the casing 11 and the second position limiting base 12c being positionally fitted to the inside of the casing 11, so that the pole post body 1201 is riveted to the casing 11.

[0302] As can be seen from the above, the first position limiting base portion 12b and the second position limiting base portion 12c each extend radially outward from the peripheral wall of the mounting hole 113 along the radial direction of the mounting hole 113, the first position limiting base portion 12b can limit the movement of the first pole column 12 relative to the casing 11 in the direction toward the inside of the casing 11, and the second position limiting base portion 12c can limit the movement of the first pole column 12 relative to the casing 11 in the direction toward the outside of the casing 11, so the first pole column 12 can be moved to the first position limiting base portion The mounting holes 113 can be easily secured via 12b and the second position limiting base portion 12c, enabling a fixed connection between the first pole column 12 and the casing 11, simplifying the assembly of the first pole column 12 and the casing 11, and eliminating the need to use other connection methods between the first pole column 12 and the casing 11. This facilitates a secure connection between the first pole column 12 and the casing 11, which is advantageous for simplifying the structure of the casing assembly 1 and the assembly process of the casing assembly 1.

[0303] Furthermore, since the pole column main body 12a, the first position limiting base 12b, and the second position limiting base 12c are integrally molded, material savings and cost reductions can be achieved. At the same time, this is convenient for ensuring the strength of the first pole column 12. When the first pole column 12 is fitted with the casing 11, during the charging and discharging process of the battery cell 10, the first pole column 12 will not easily detach from the casing 11 due to vibration or external pulling. This makes it less susceptible to cracking or damage due to vibration or external pulling, improving the stability and reliability of the casing assembly 1 and the battery cell 10.

[0304] For example, the axial direction of the mounting hole 113 is the third direction Z, and the casing 11 has a mounting hole 113 formed through the side wall in the third direction Z, and the first position limiting base portion 12b and the second position limiting base portion 12c are installed at both ends of the pole column main portion 12a along the third direction Z.

[0305] It should be explained that in the above technical proposal, the pole column of the casing assembly 1 may be one or more, of which at least one pole column is a first pole column 12 including an integrally molded pole column main body 12a, a first position limiting base 12b, and a second position limiting base 12c, and a part of the pole column on the casing 11 is the first pole column 12 including an integrally molded pole column main body 12a, a first position limiting base 12b, and a second position limiting base 12c, and another part of the pole column may be of a different structure.

[0306] In this application, the first pole 12 may be a positive pole or a negative pole, and is not limited thereto.

[0307] For example, referring to Figure 57, which is a schematic diagram of the assembly process of a first pole column 12 and a first wall 110 provided by some embodiments of the present application, the first position limiting base 12b, the second position limiting base 12c, and the pole column main body 12a are integral members, and before the first pole column 12 is riveted to the casing 11, one of the first position limiting base 12b and the second position limiting base 12c can extend axially through the mounting hole 113, and the other can extend radially through the mounting hole 113, and after drilling the pole column main body 12a in the mounting hole 113, the first position limiting base 12b and the second position limiting base 12c can be riveted using a tool or the like so that they extend radially through the mounting hole 113, thereby achieving riveted fixation of the first pole column 12 to the casing 11.

[0308] In some embodiments, as shown in Figures 60, 61, and 65, the thickness of the first position limiting base 12b in the axial direction is t1, where 2mm ≤ t1 ≤ 3.2mm. This allows for simultaneous balance between the rivet joint strength of the first pole column 12 at the first position limiting base 12b and the volumetric energy density of the battery cell 10. By setting the thickness of the first position limiting base 12b to be large considering the rivet joint strength of the first pole column 12, a decrease in the volumetric energy density of the battery cell 10 can be avoided. At the same time, by setting the thickness of the first position limiting base 12b to be small considering the volumetric energy density of the battery cell 10, a deterioration in the rivet joint strength of the first pole column 12 at the first position limiting base 12b can be avoided.

[0309] For example, t1 may be 2mm, 2.2mm, 2.5mm, 2.7mm, 2.9mm, 3mm, or 3.2mm.

[0310] In some embodiments, as shown in Figures 60, 61, and 62, the width of the first position limiting base 12b in the radial direction of the mounting hole 113 is x1, where x1 ≥ 1 mm. This enhances the position limiting effect of the first position limiting base 12b on the first pole column 12 and improves the reliability of the riveted joint between the first pole column 12 and the casing 11 to some extent. The width d of the first position limiting base 12b is understood as the distance from the outer peripheral wall of the pole column main body 12a along the radial direction of the mounting hole 113 to the outer wall of the first position limiting base 12b.

[0311] For example, x1 could be 1mm, 1.2mm, 1.5mm, 1.8mm, or 2mm.

[0312] In some embodiments, as shown in Figures 60, 61, and 62, the thickness of the second position limiting base 12c in the axial direction is t2, where t2 ≤ 2 mm. This allows for simultaneous balance between the rivet joint strength of the first pole column 12 at the second position limiting base 12c and the volumetric energy density of the battery cell 10. By setting the thickness of the second position limiting base 12c to be large considering the rivet joint strength of the first pole column 12, a decrease in the volumetric energy density of the battery cell 10 can be avoided. At the same time, by setting the thickness of the second position limiting base 12c to be small considering the volumetric energy density of the battery cell 10, a deterioration in the rivet joint strength of the first pole column 12 at the second position limiting base 12c can be avoided.

[0313] For example, t2 may be 2mm, 1.8mm, 1.5mm, 1.4mm, or 1.2mm.

[0314] In some embodiments, the distance between the end of the second position limiting base 12c that is separated from the first position limiting base 12b and the inner wall of the casing 11 in the axial direction of the mounting hole 113 is 2 mm or less, thereby further improving the energy density of the battery cell 10.

[0315] In some embodiments, at least one of the first position limiting base 12b and the second position limiting base 12c and the pole column main body 12a are separate members and are fixedly connected. In other words, the first position limiting base 12b or the second position limiting base 12c and the pole column main body 12a may be separate members and fixedly connected, or both the first position limiting base 12b and the second position limiting base 12c may be separate members and fixedly connected to the pole column main body 12a. In this technical proposal, since at least one of the first position limiting base 12b and the second position limiting base 12c and the pole column main body 12a are separate members, the operation when assembling the first pole column 12 and the casing 11 becomes easier, the difficulty of assembly can be reduced, and it is advantageous for later removal and replacement, and the cost of use is reduced.

[0316] In some embodiments, at least one of the first position limiting base portion 12b and the second position limiting base portion 12c is welded to the pole column main portion 12a.

[0317] In some embodiments, the pole column main body 12a, the first position limiting base 12b, and the second position limiting base 12c are integral components. In this way, the assembly process is simplified by reducing the assembly steps between the first pole column 12 and the casing 11, thereby improving work efficiency. At the same time, by installing the pole column main body 12a, the first position limiting base 12b, and the second position limiting base 12c as integral components, the attachment between the first pole column 12 and the casing 11 can be made more secure, and the risk of the separate pole column falling off between the first pole column 12 and the casing 11 due to loosening of the components can be reduced.

[0318] Next, the materials of the pole column main body 12a, the first position limiting base 12b, and the second position limiting base 12c may be the same or different, and of course, the pole column main body 12a, the first position limiting base 12b, and the second position limiting base 12c may be separate members.

[0319] In some embodiments, as shown in Figures 60, 61, and 62, the battery 100 further includes an insulating seal member 8, which is provided between the first pole 12 and the casing 11 to achieve insulation and sealing between the first pole 12 and the casing 11.

[0320] In some embodiments, as shown in Figures 60, 61, and 62, the insulating seal member 8 includes an insulating member 81 and a seal member 82, wherein the insulating member 81 is provided between the first position limiting base 12b and the casing 11, and the seal member 82 is provided between the second position limiting base 12c and the casing 11, and a part of the insulating member 81 and / or a part of the seal member are fitted between the pole column main body 12a and the peripheral wall of the mounting hole 113, so that the insulating member 81 can perform an insulating role between the first position limiting base 12b and the casing 11, ensuring the reliability of the insulation, while the seal member 82 can perform a sealing role to prevent the electrolyte inside the casing 11 from spilling.

[0321] In some embodiments, as shown in Figures 60, 61, and 62, a fitting groove for accommodating the insulating member 81 is formed on the outer wall of the casing 11, making it easier to position and attach the insulating member 81 and, to some extent, avoiding misalignment of the insulating member 81 during the riveting process between the first pole column 12 and the casing 11. At the same time, assuming that the casing 11 can be used reliably, the installation of the fitting groove is advantageous in reducing the height to which the insulating member 81 protrudes from the outer wall of the casing 11, which is advantageous in reducing the height to which the first pole column 12 protrudes from the outer wall of the casing 11, thereby improving the volumetric energy density (VED) of the battery cell 10. Of course, a fitting groove does not necessarily have to be formed on the outer wall of the casing 11.

[0322] In some embodiments, as shown in Figures 60, 61, and 62, a fitting projection is formed on the inner wall of the casing 11, and the fitting projection abuts against the sealing member 82, which is advantageous in improving the sealing reliability of the sealing member 82. Of course, a fitting projection does not have to be formed on the inner wall of the casing 11.

[0323] For example, in the examples shown in Figures 60, 61, and 62, a fitting groove for accommodating the insulating member 81 is formed on the outer wall of the casing 11, and a fitting projection is formed on the inner wall of the casing 11, with the fitting projection contacting the sealing member 82.

[0324] Selectively, the insulating seal member 8 may be an integral member, that is, the insulating member 81 and the seal member 82 may be an integral member, in which case the materials of the insulating member 81 and the seal member 82 may be the same or different, and of course, the insulating member 81 and the seal member 82 may be separate members.

[0325] Specifically, by combining Figures 40 to 42, the first pole column 12 can include a stopper portion 1281 and a drilling portion 1282 before riveting. During assembly, the stopper portion 1281 is secured inside the casing 11, and after drilling the drilling portion 1282 into the mounting hole 113, the portion of the drilling portion 1282 located outside the casing 11 is riveted to form a flange portion 1283. The flange portion 1283 is secured outside the casing 11, thereby achieving the installation of the first pole column 12. For explanation purposes, the drilling portion 1282 refers to the pole column main body portion 12a, the stopper portion 1281 refers to the second position limiting base portion 12c, and the flange portion 1283 refers to the first position limiting base portion 12b.

[0326] By selectively combining Figures 40 and 41, the casing assembly 1 may include several seal pads fitted between the casing 11 and the first pole post 12, such as the first seal pad 191 and the second seal pad 192 shown in Figure 40. The seal pads are assembled in place before riveting, and after riveting the first pole post 12, the first pole post 12 presses against the seal pads to form a seal, thereby improving the sealing performance of the mating area between the first pole post 12 and the casing 11 by utilizing the seal pads. The number, position, and material of the seal pads are not limited; for example, the material may be silicone, plastic, etc.

[0327] Selectively, by combining Figure 41, the flange portion 1283 may have a length c of 1 mm or more and a thickness d of 2 mm or more in order to improve the rivet joint strength of the first pole column 12. If the length c of the flange portion 1283 is less than 1 mm and / or the thickness d is less than 2 mm, the reliability of the first pole column 12 and the casing 11 decreases under relatively strong vibrations.

[0328] Furthermore, in other embodiments of the present application, by combining Figures 6 and 7, the first pole column 12 can be attached to the casing 11 as a separate structure by welding. For example, the first pole column 12 includes a first portion 1291 and a second portion 1292, where at least a part of the first portion 1291 is located outside the casing 11 and at least a part of the second portion 1292 is located inside the casing 11. The first pole column 12 can be attached by drilling a mounting hole 113 in at least one of the first portion 1291 and the second portion 1292 and welding (for example, laser welding) the other portion.

[0329] In some selective embodiments, combining Figures 45 and 46 results in multiple first pole columns 12, all located on the same side surface of the casing 11, thus facilitating installation and improving assembly efficiency.

[0330] It should be noted that the arrangement of multiple first pole columns 12 on the same side surface is not limited, and for example, if the cross-section of the first pole column 12 is an elongated shape, for example, if the length of the cross-section is three times or more the width of the cross-section, for example, if it is elliptical, racetrack-shaped, or rectangular, it has relatively good adaptability to a thin, flat casing 11. For example, multiple first pole columns 12 are all provided on one side surface (denoted as the first wall surface 110) in the height direction of the casing 11, the length direction of each first pole column 12 all coincides with the length direction of the first wall surface 110 of the casing 11, and the multiple first pole columns 12 are separated along the length direction and / or width direction of the first wall surface 110.

[0331] For example, in the example shown in Figure 45, if the first wall surface 110 has two first pole columns 12, the two first pole columns 12 are separated along the longitudinal direction of the first wall surface 110. Selectively combining Figure 45, the portion of the first pole column 12 located outside the casing 11 (referred to as the pole column exterior) is annular, and in the longitudinal direction of the first wall surface 110, the length a1 of the inner ring of the pole column exterior is at least 1 / 3 of the length a0 of the first wall surface 110, and in the width direction of the first wall surface 110, the width b1 of the inner ring of the pole column exterior is at least 3 / 4 of the width b0 of the first wall surface 110. This is advantageous in providing a relatively large area for the first pole column 12 to electrically connect with the bus member, thereby facilitating further improvement of the current passing capability of the first pole column 12. For example, the length a1 of the inner ring outside the pole column is 50 mm or more, and the width b1 of the inner ring outside the pole column is 30 mm or more.

[0332] Furthermore, combining with Figure 45, when the first wall surface 110 has two first pole columns 12 and the two first pole columns 12 are separated along the longitudinal direction of the first wall surface 110, in some selective embodiments, the first pole column 12 includes a portion located inside the casing 11 (referred to as the pole column interior), and in the longitudinal direction of the first wall surface 110, the length of the pole column interior is 1 / 3 or more of the length of the first wall surface 110, and in the width direction of the first wall surface 110, the width of the pole column interior is 3 / 4 or more of the width of the first wall surface 110. This is advantageous in providing the first pole column 12 with a relatively large area for electrical connection with the conductive part 22, and facilitates further improvement of the current passing capability of the first pole column 12. Exemplarily, the length of the pole column interior is 50 mm or more, and the width of the pole column interior is 30 mm or more.

[0333] Furthermore, for example, in the example shown in Figure 46, if the first wall surface 110 has four first pole columns 12, two of the first pole columns 12 are spaced apart along the width direction of the first wall surface 110 to form one pair, and a total of two pairs are spaced apart along the length direction of the first wall surface 110. Selectively combining Figure 46, the portion of the first pole column 12 located outside the casing 11 (referred to as the pole column exterior) is ring-shaped, and in the length direction of the first wall surface 110, the length a2 of the inner ring of the pole column exterior is 1 / 3 or more of the length a0 of the first wall surface 110, and in the width direction of the first wall surface 110, the width b2 of the inner ring of the pole column exterior is 1 / 5 or more of the width b0 of the first wall surface 110. This is advantageous in providing a relatively large area for the first pole column 12 to electrically connect with the bus member, thereby facilitating further improvement of the current passing capability of the first pole column 12. For example, the length a2 of the inner ring outside the pole column is 50 mm or more, and the width b2 of the inner ring outside the pole column is 8 mm or more.

[0334] Furthermore, combining with Figure 46, if the first wall surface 110 has four first pole columns 12, two of these first pole columns 12 form a pair separated along the width direction of the first wall surface 110, and a total of two pairs separate along the length direction of the first wall surface 110, then in some selective embodiments, the first pole columns 12 include a portion located inside the casing 11 (referred to as the pole column interior), and in the length direction of the first wall surface 110, the length of the pole column interior is 1 / 3 or more of the length of the first wall surface 110, and in the width direction of the first wall surface 110, the width of the pole column interior is 1 / 5 or more of the width of the first wall surface 110. This is advantageous in providing the first pole columns 12 with a relatively large area for electrical connection with the conductive part 22, and facilitates further improvement of the current passing capability of the first pole columns 12. Exemplarily, the length of the pole column interior is 50 mm or more, and the width of the pole column interior is 8 mm or more.

[0335] In some embodiments, when Figures 45 and 46 are combined, the portion of the first pole column 12 is located inside the casing 11, the portion of the first pole column 12 is located outside the casing 11, and the orthographic area of ​​the portion of the first pole column 12 located outside the casing 11 on the first wall surface 110 is 5% or more of the area of ​​the first wall surface 110. For example, the orthographic area of ​​the portion of the first pole column 12 located outside the casing 11 on the first wall surface 110 is 5%, 6%, 7%, 8%, 9%, 10%, or more of the area of ​​the first wall surface 110. This is advantageous in increasing the connection area between the first pole column 12 and the bus member, improving the effective current passage area between the first pole column 12 and the bus member, and improving the charging speed of the battery cell 10.

[0336] Furthermore, in some embodiments, when Figure 47 is combined, the vertical height t1 from the portion of the first pole column 12 that protrudes from the outer surface of the first wall surface 110 (referred to as the outer pole column) to the first wall surface 110 may be 3.2 mm or less, and the vertical height t2 from the portion of the first pole column 12 that protrudes from the inner surface of the first wall surface 110 (referred to as the inner pole column) to the first wall surface 110 may be 2 mm or less, thereby improving the volumetric energy density of the battery cell 10.

[0337] Figure 48 is a schematic cross-sectional view of a casing assembly 1 provided in some embodiments of the present application, Figure 49 is a schematic cross-sectional view of a casing assembly 1 provided in some embodiments of the present application, Figure 50 is an orthographic projection of a battery cell 10 provided in some embodiments of the present application, Figure 51 is a cross-sectional view along the EE line in Figure 50, and Figure 52 is a schematic local cross-sectional view of a battery cell 10 provided in some embodiments of the present application. Referring to Figures 48 to 52, in the embodiments of the present application, specifically, the casing 11 includes a casing body 111 and a casing cover 112, the casing body 111 has a rectangular annular structure and one or both ends are open, if one end is open there is one casing cover 112 which is fitted to the open position, if both ends are open there are two casing covers 112 which are fitted to the open ends of the casing body 111.

[0338] More specifically, if the casing 11 includes a casing body 111 and a casing cover 112, and one end of the casing body 111 is open, the casing body 111 is a single molded product and may specifically be a rectangular structure formed by stretching. In this case, the first pole column 12 can be provided on at least one of either the casing body 111 or the casing cover 112. Exemplarily, combining Figure 48, the first pole column 12 may specifically be installed on the end of the casing body 111 that is away from the casing cover 112. When the battery cell 10 is used in a vibrating environment, the amplitude of the connection between the casing body 111 and the casing cover 112 is relatively small, and the connection point between the casing body 111 and the casing cover 112 is less prone to cracking, thus improving the reliability of the battery cell 10. Furthermore, the wall thickness of the casing body 111 can be reduced, thereby reducing costs, weight, and enabling miniaturization of the battery cell 10.

[0339] As a selective solution, combining Figure 48 again, if there are multiple first pole columns 12, all first pole columns 12 are provided at one end of the casing body 111 that is away from the casing cover 112. This improves the reliability of the battery cell 10 because, when the battery cell 10 is used in a vibrating environment, the amplitude of the connection between the casing body 111 and the casing cover 112 is relatively small, and the connection point between the casing body 111 and the casing cover 112 is less likely to crack. Furthermore, the wall thickness e1 of the end wall of the casing body 111 that is away from the casing cover 112 can be reduced to 2 mm or less, and the wall thickness e2 of the side wall connecting the end wall of the casing body 111 and the casing cover 112 can be reduced to 0.8 mm or less, thereby reducing costs, weight, and enabling miniaturization of the battery cell 10.

[0340] When the first housing groove 12110 is provided on the first pole post 12, corresponding to the mounting hole 113, the thickness of the portion of the first housing groove 12110 on the side away from the active material coated portion 21 of the first pole post 12 is thin, so welding of the conductive portion 22 and the first pole post 12 can be achieved from the outside of the casing 11, and combining the above as shown in Figure 48, the casing 11 includes the casing body 111 and the casing cover 112, and the casing cover 112 is the casing body 11 When provided at the open end of 1, even if the first pole post 12 is provided at the sealed end of the casing body 111, there is no need to worry that it will be difficult to weld the conductive part 22 and the first pole post 12 from inside the casing 11. The conductive part 22 and the first pole post 12 can be welded from outside the casing 11. As a result, by providing the first pole post 12 at the sealed end of the casing body 111, the connection stability and reliability between the casing body 111 and the casing cover 112 can be improved.

[0341] When the second housing groove 12120 is provided on the first pole column 12, welding of the conductive part 22 and the first pole column 12 can be achieved from outside the casing 11 through the groove opening of the second housing groove 12120. Combining this with the arrangement shown in Figure 48, when the casing 11 includes a casing body 111 and a casing cover 112, and the casing cover 112 is provided at the open end of the casing body 111, even if the first pole column 12 is provided at the sealed end of the casing body 111, there is no need to worry that welding of the conductive part 22 and the first pole column 12 from inside the casing 11 will be difficult. The conductive part 22 and the first pole column 12 can be welded from outside the casing 11, thereby improving the connection stability and reliability between the casing body 111 and the casing cover 112.

[0342] Of course, by combining with Figure 49, in other embodiments of the present invention, all first pole posts 12 can be provided on the casing cover 112 as needed. This facilitates the assembly of the first pole posts 12 and the casing cover 112, and is not limited to this embodiment.

[0343] Furthermore, by combining Figures 50 to 52, in the embodiment of the present application, if there are multiple first pole posts 12, the first pole posts 12 can also be arranged on two different surfaces of the casing 11. For example, multiple first pole posts 12 can be arranged on adjacent surfaces of the casing 11, or multiple first pole posts 12 can be arranged on opposing surfaces of the casing 11.

[0344] When first pole posts 12 are provided on opposing surfaces of the casing 11, conductive portions 22 can extend from positions close to the first pole posts 12 on each side of the active material coated portion 21, and the conductive portions 22 are fitted and connected to the adjacent first pole post 12. This improves the problem of the tab portion 221 being pulled by the first pole post 12 on the same side, causing the connection between the tab portion 221 and the active material coated portion 21 to break, thereby improving the reliability of the battery cell 10. It should be noted that the first pole posts 12 on both sides may be homologous or different, and the method of connecting the first pole posts 12 on both sides to the conductive portions 22 may be homologous or different, and is not limited thereto.

[0345] Of course, in other embodiments of the present application, the first pole column 12 may be installed on the surface of the casing 11 that has the largest area. Also, for example, in some selective embodiments of the present application, the first pole column 12 may be located on the top surface of the casing 11. Furthermore, for example, in some selective embodiments of the present application, the first pole column 12 may be located on the bottom surface of the casing 11. In the case where the first pole column 12 is located on the bottom surface of the casing 11, the electrolyte can be contained using the housing portion 121, thereby improving the cycle life of the battery cell 10. Furthermore, when the first pole column 12 is located on the bottom surface of the casing 11 and the support 3 is located at the bottom of the active material coated portion 21, the contact area between the support 3 and the active material coated portion 21 can be increased, thereby reducing the problem of stress concentration and allowing other support structural members to be omitted.

[0346] When Figure 43 is combined, several embodiments of the present invention have a pressure release section 16 on the casing 11. The specific configuration of the pressure release section 16 is not limited and may be, for example, an explosion-proof valve or a vulnerable section, and is used to release pressure when the pressure inside the battery cell 10 is relatively high, thereby improving the reliability of the battery cell 10.

[0347] Selectively, the pressure relief section 16 and the first pole column 12 can be located on the same side of the casing 11. This facilitates processing and assembly. Alternatively, selectively, the pressure relief section 16 and the first pole column 12 may be located on opposing sides of the casing 11, respectively. This saves space, increases the volume of the first pole column 12, and reduces the adverse effect of the pressure relief section 16 on the pole column 12 when releasing pressure.

[0348] Referring again to Figures 48 and 53, in this embodiment, the pressure release section 16 may be provided on the casing cover 112 as needed. The casing cover 112 does not need to have the function of attaching the first pole post 12, and the connection position between the casing cover 112 and the casing 11 is relatively less affected by vibrations during the charging and discharging process of the battery cell 10 and is less prone to cracking. As a result, the thickness of the casing cover 112 can be set relatively thin, which further facilitates the processing and manufacturing of the pressure release section 16. For example, to sufficiently improve the manufacturability of the battery cell 10, the pressure release section 16 can be easily formed in the casing cover 112 by an integrally molded notch. It should be noted that in this embodiment, the first pole post 12 may be provided on the casing body 111 or the casing cover 112, and is not limited thereto. For example, the pressure release section 16 can be integrally molded with the casing cover 112, which facilitates processing, simplifies assembly, improves production efficiency, and reduces costs.

[0349] Referring again to Figures 3 to 5, Figure 18, and Figures 23 to 24, the battery cell 10 according to a specific embodiment of the present application will be described.

[0350] Referring to Figures 3 to 5, the battery cell 10 is a rectangular parallelepiped, and the height direction of the battery cell 10 is the first direction Z, the length direction of the battery cell 10 is the second direction X, and the thickness direction of the battery cell 10 is the third direction Y. The battery cell 10 includes a casing 11, which includes a casing body 111 and a casing cover 112, the casing body 111 has a rectangular annular structure, one end of the casing body 111 is open along the first direction Z and the other end of the casing body 111 is sealed along the first direction Z, and the casing cover 112 is installed as a cover on the open position of the casing body 111.

[0351] Referring to Figures 3 to 5, two pole columns are provided at the sealing end of the casing body 111 along the first direction Z, and the two pole columns are separated along the second direction X so that they become a positive pole column and a negative pole column, respectively. Both pole columns are first pole columns 12 on which a housing section 121 is installed, and the housing section 121 includes a second housing groove 12120, specifically the first pole column 12 includes a second end wall 12121 and a second side wall 12123, the second end wall 12121 is located on the side of the second side wall 12123 that is close to the casing cover 112, and the second end wall 12121 and the second side wall 12123 are A second housing groove 12120 is formed surrounding the pole column 12, the surface of the pole column 12 away from the casing cover 112 is the outer end face 123 of the pole column, the opening of the second housing groove 12120 is formed on the outer end face 123 of the pole column, and a first through hole 12130 is opened in the second end wall 12121, the first through hole 12130 is located in close proximity to the second side wall 12123 of the second end wall 12121.

[0352] Referring to Figures 5 and 18, the battery cell 10 further includes a battery core assembly 2, which includes an active material coated portion 21 and a tab portion 221. The active material coated portion 21 is housed within the casing 11, and the tab portion 221 passes through a first through hole 12130 and enters a second housing groove 12120, and is welded to a second end wall 12121, electrically connecting the active material coated portion 21 and the first pole column 12 via the tab portion 221.

[0353] By combining Figures 18, 23, and 24, the first cover plate 13 is fitted into the groove opening of the second housing groove 12120. After welding of the tab portion 221 to the second end wall 12121 is completed, the groove opening of the second housing groove 12120 is sealed by utilizing the fitting between the first cover plate 13 and the first pole post 12. The first cover plate 13 is welded to the first pole post 12 to form an electrical connection. Subsequently, if a bus member is used to make an electrical connection between the battery cells 10, the bus member may be welded to the first cover plate 13 to achieve an electrical connection with the first pole post 12.

[0354] In the above proposed technology, on the one hand, by installing the second housing groove 12120 on the first pole column 12, the weight of the first pole column 12 can be reduced to some extent, thereby improving the gravimetric energy density of the battery cell 10 and the battery 100. On the other hand, the groove opening of the second housing groove 12120 is formed on the outer end surface 123 of the pole column, and the outer end surface 123 of the pole column is the surface away from the active material coated portion 21 of the first pole column 12, so the second housing groove 12120 is the active material coated portion The tab portion 221 can be opened in a direction away from the fabric portion 21, thereby accommodating at least a part of the tab portion 221 in the second housing groove 12120. This allows for easy accommodation and organization of the tab portion 221 through the groove of the second housing groove 12120, and facilitates welding operations between the tab portion 221 and the first pole column 12 through the groove of the second housing groove 12120. This reduces the difficulty of producing the battery cell 10 and improves the production efficiency of the battery cell 10.

[0355] Furthermore, since welding of the tab portion 221 and the first pole column 12 can be achieved from outside the casing 11, the first pole column 12 may be provided at the sealing end of the casing 111. In this way, when the battery cell 10 is used in a vibrating environment, the amplitude of the connection between the casing body 111 and the casing cover 112 is relatively small, cracking is less likely to occur at the connection point between the casing body 111 and the casing cover 112, the reliability of the battery cell 10 can be improved, the wall thickness of the casing body 111 can be reduced, which is advantageous for reducing costs, reducing weight, and miniaturizing the battery cell 10.

[0356] At the same time, since the second housing groove 12120 communicates with the inside of the casing 11 through the first through hole 12130, the second housing groove 12120 can be used as a buffer and temporary storage structure for the electrolyte, allowing more electrolyte to be stored in the casing 11. As the electrolyte is consumed during the charging and discharging process of the battery cell 10, having more electrolyte can extend the service life of the battery cell 10. Furthermore, since the second housing groove 12120 communicates with the inside of the casing 11 through the first through hole 12130, the second housing groove 12120 can be used as a gas containment and buffer structure for gases generated inside the battery core assembly 2, reducing the expansion of the battery cell 10 and improving the reliability and stability of the battery cell 10.

[0357] In some embodiments, combining Figures 74 and 75, the battery cell 10 further includes an outer insulating member 5 wrapped around the outside of the casing 11. In this solution, the outer insulating member 5 serves an insulating role, separating the casing 11 from external components and providing insulation. For example, the outer insulating member 5 is a blue film.

[0358] In some embodiments, when Figure 74 is combined, the casing 111 has a first wall 110, the first wall 110 has mounting holes 113, the pole body 1201 is installed in the mounting holes 113, the battery cell 10 further includes a patch 9 covering the outside of the first wall 110, the outer insulating member 5 includes an outer insulating film 52 which is an integral diaphragm, the outer insulating film 52 has a connection portion 51, the connection portion 51 extends to the outside of the first wall 110 and connects to the patch 9.

[0359] In the above proposed technology, in order to facilitate the connection and installation of the connector 51 and the patch 9, the connector 51 can be superimposed on the patch 9 along the axial direction of the mounting hole 113. In this case, the outer insulating film 52 and the patch 9 can separate at least the first pole post 12 on the first wall 110 from the casing 11, improving the insulation reliability between the first pole post 12 and the casing 11, thereby improving the reliability of use of the battery cell 10. For example, in the example shown in Figures 74 and 75, the connector 51 extends in an annular shape along the outer circumference of the first wall 110, and the outer insulating member 5 can be wrapped around all walls of the casing 11 other than the first wall 110. The connector 51 is provided between the patch 9 and the first wall 110, and the patch 9 can play a certain protective role to the connection between the connector 51 and the patch 9.

[0360] Selectively, the outer insulating member 5 is bonded to the casing 11, and the patch 6 is bonded to the first wall 11a.

[0361] In some embodiments, the first pole column 12 has a solid structure, and the second welded portion 72 is formed on the part of the first pole column 12 located on the outside of the casing 11. By adopting this method, the structure of the first pole column 12 is simple and easy to manufacture.

[0362] In some embodiments, the minimum distance between the edge of the outer insulating film 52 and the first pole post 12 is 3 mm or more. This means that the creepage distance between the first pole post 12 and the casing 11 may also be 3 mm or more, which is advantageous for improving the dielectric strength between the first pole post 12 and the casing 11. For example, the minimum distance t between the connection portion 51 and the pole post 12 may be 3 mm, 4 mm, 4.7 mm, 5 mm, or 5.2 mm, etc.

[0363] In some embodiments, as shown in Figures 56 to 60 and Figure 66, the plane on which the cross-section of the mounting hole 113 is located is used as the projection plane, and along the direction perpendicular to the projection plane, the projected area of ​​the first weld 71 on the projection plane is 0.1% or more of the projected area of ​​the first wall 110 on the projection plane.

[0364] In the above proposed technology, if the cross-section of the mounting hole 113 is perpendicular to the axial direction of the mounting hole 113, and the projection direction under the above conditions is parallel to the axial direction of the mounting hole 113, then the projected area of ​​the first welded portion 71 on the projection plane is understood to be the projected area of ​​the connection region between the conductive portion 22 and the pole column body 1201 on the projection plane. Therefore, the projected area of ​​the first welded portion 71 on the projection plane can reflect the size of the area of ​​the connection region between the conductive portion 22 and the pole column body 1201, and the projected area of ​​the first welded portion 71 on the projection plane satisfies the above conditions. This reduces the equivalent resistance between the conductive portion 22 and the pole column body 1201 to some extent, increases the current passage area of ​​the first pole column 12, improves the current passage capability of the first pole column 12, which is advantageous for improving the charging speed of the battery cell 10, which is advantageous for improving the rapid charging performance of the battery cell 10, and at the same time, is advantageous to some extent for improving the heat diffusion capability of the pole column 12.

[0365] In the above proposed technology, by setting the first welded portion 71 between the conductive portion 22 and the pole column body 1201 on the projection plane such that the projected area of ​​the first welded portion 71 is 0.1% or more of the projected area of ​​the first wall 110 on the projection plane, the effective current passage area between the conductive portion 22 and the pole column body 1201 becomes 0.1% or more of the projected area of ​​the first wall 110 on the projection plane, thereby increasing the effective current passage area between the conductive portion 22 and the pole column body 1201, increasing the current passage area of ​​the first pole column 12, and improving the current passage capability of the first pole column 12. This is advantageous for improving the charging speed of the battery cell 10, and at the same time, to some extent, is also advantageous for improving the heat dissipation capability of the first pole column 12, reducing the current passage temperature of the first pole column 12, and thereby advantageous for reducing the risk of runaway operation of the battery cell 10.

[0366] In some embodiments, along a direction perpendicular to the projection plane, the projected area of ​​the first weld 71 on the projection plane is 0.15% or more of the projected area of ​​the first wall 110 on the projection plane.

[0367] In the above proposed technology, by setting the orthographic area of ​​the first welded portion 71 on the projection surface to be 0.15% or more of the orthographic area of ​​the first wall 110 on the projection surface, the effective current passage area between the conductive portion 22 and the pole column body 1201 is further increased, which is advantageous for improving the rapid charging performance of the battery cell 10.

[0368] In some embodiments, the projected area of ​​the first weld 71 on the projection plane is 5 mm². 2 That concludes the explanation. For example, the projected area of ​​the first weld 71 on the projection plane is 5 mm². 2 , 6mm 2 , 8mm 2 9mm 2 , or 10mm 2 You can also use these.

[0369] In the above proposed technology, the projected area of ​​the first welded portion 71 on the projection plane is 5 mm 2 By installing the equipment as described above, the current transmission capacity and heat diffusion capacity of the first pole column 12 are effectively improved.

[0370] For example, in the example shown in Figure 59, the projection of the first weld 71 on the projection plane extends in an elongated shape (the corresponding weld joint is helical and elongated), and as an example of the case where the projection of the first weld 71 on the projection plane extends along a straight line, the length of the projection of the first weld 71 on the projection plane is 10 mm or more, and the width of the projection of the first weld 71 on the projection plane is 5 mm or more. Of course, the projection of the first weld 71 on the projection plane may also extend along a curve (including, but not limited to, a smooth curve or a broken line), for example, the projection of the first weld 71 on the projection plane may extend in a closed ring shape (e.g., a ring shape, a polygonal ring, etc.). The shape of the projection of the first weld 71 on the projection plane may also be a solid circle.

[0371] Furthermore, the projected area of ​​the first welded portion 71 on the projection plane is 7 mm². 2 That concludes the explanation. For example, the projected area of ​​the first weld 71 on the projection plane is 7 mm². 2 7.8mm 2 9.5mm 2 , or 11mm 2 You can also use these.

[0372] As an example, if the shape of the projection of the first weld 71 on the projection plane is a solid circle, the diameter of the circle corresponding to the projection of the first weld 71 on the projection plane is 3 mm or more.

[0373] In some embodiments, the overlapping portion of the conductive portion 22 and the pole column body 1201 along a direction perpendicular to the projection plane is the weldable region of the conductive portion 22. That is, the weldable region of the conductive portion 22 overlaps with the pole column body 1201 along a direction perpendicular to the projection plane. In other words, along a direction perpendicular to the projection plane, the projection of the weldable region of the conductive portion 22 on the projection plane overlaps with at least a portion of the projection of the pole column body 1201 on the projection plane. Thus, the weldable region of the conductive portion 22 can be understood as a region weldable to the pole column body 1201 provided by the conductive portion 22. Therefore, the area of ​​the weldable region is necessarily greater than or equal to the orthographic projection area of ​​the first weld portion 71 on the projection plane.

[0374] Of these, along the direction perpendicular to the projection plane, the projected area of ​​the first welded portion 71 on the projection plane is 20% or more of the area of ​​the weldable region of the conductive portion 22. This is based on the premise that the current passing capacity and heat diffusion capacity of the first pole column 12 will be appropriately improved, and the projected area of ​​the first welded portion 71 on the projection plane will have an appropriate proportion in order to facilitate the welding operation between the conductive portion 22 and the pole column body 1201.

[0375] For example, the orthographic projected area of ​​the first weld 71 on the projection plane is 20%, 25%, 35%, 40%, 50%, or 60% of the area of ​​the weldable region of the conductive portion 22.

[0376] In some embodiments, along a direction perpendicular to the projection plane, the projected area of ​​the first welded portion 71 on the projection plane is 30% or more of the area of ​​the weldable region of the conductive portion 22.

[0377] In the above proposed technology, by setting the orthographic area of ​​the first welded portion 71 on the projection plane to be 30% or more of the area of ​​the weldable region of the conductive portion 22, it is advantageous to further balance the current passing capability of the first pole column 12 with the convenience of welding operations. For example, the orthographic area of ​​the second welded portion 7 on the projection plane may be 30%, 45%, 55%, 65%, or 70% of the area of ​​the weldable region of the guide portion 22.

[0378] In some embodiments, the cross-section of the mounting hole 113 is a projection plane, and the overlapping portion of the second convergence portion 2213 and the first pole column 12 along a direction perpendicular to the projection plane is the weldable region of the tab portion 221, and the weldable region of the tab portion 221 overlaps with the first pole column 12 along a direction perpendicular to the projection plane, in other words, along a direction perpendicular to the projection plane, the orthographic projection of the weldable region of the tab portion 221 on the projection plane overlaps with at least a portion of the orthographic projection of the first pole column 12 on the projection plane, and thus the weldable region of the tab portion 221 can be understood as the region weldable to the first pole column 12 provided by the tab portion 221, and therefore the area of ​​the weldable region of the tab portion 221 is necessarily greater than or equal to the orthographic projection area of ​​the first weld portion 71 on the projection plane.

[0379] Of these, the area of ​​the weldable region of the tab portion 221 is 40% or more of the total area of ​​the tab portion 221, so the tab portion 221 can provide a sufficient weldable region to lay the foundation for improving the current passage capacity and heat diffusion capacity of the first pole column 12. For example, the area of ​​the weldable region of the tab portion 221 may be 40%, 45%, 50%, 65%, or 70% of the total area of ​​the tab portion 221.

[0380] In some embodiments, the area of ​​the weldable region of the tab portion 221 is 60% or more of the total area of ​​the tab portion 221. In the above technical proposal, by installing the tab portion 221 so that the area of ​​the weldable region of the tab portion 221 is 60% or more of the total area of ​​the tab portion 221, the tab portion 221 can further provide a weldable region sufficient to lay the foundation for improving the current passage capacity and heat diffusion capacity of the first pole column 12. For example, the area of ​​the weldable region of the tab portion 221 may be 60%, 68%, 72%, or 80% of the total area of ​​the tab portion 221.

[0381] In some embodiments, as shown in Figures 62 to 66, the conductive portion 22 includes a tab portion 221 and an adapter sheet 222, the connection and installation of the adapter sheet 222 refer to the preceding paragraph, and the overlapping portion of the adapter sheet 222 and the first pole column 12 along the direction perpendicular to the projection plane is the weldable region of the adapter sheet 222, the weldable region of the adapter sheet 222 overlaps with the first pole column 12 along the direction perpendicular to the projection plane, in other words, along the direction perpendicular to the projection plane, the orthographic projection of the weldable region of the adapter sheet 222 on the projection plane overlaps with at least a portion of the orthographic projection of the first pole column 12 on the projection plane, thus the weldable region of the adapter sheet 222 can be understood as the region weldable to the first pole column 12 provided by the adapter sheet 222, and therefore the area of ​​the weldable region of the adapter sheet 222 is necessarily greater than or equal to the orthographic projection area of ​​the first weld portion 71 on the projection plane.

[0382] Of these, the area of ​​the weldable region of the adapter sheet 222 is 1 / 12 or more of the area of ​​the adapter sheet 222, so the adapter sheet 222 can provide a sufficient weldable region to lay the foundation for improving the current passage capability and heat diffusion capability of the first pole column 12.

[0383] For example, the area of ​​the weldable region of the adapter sheet 222 is 1 / 11, 1 / 10, 1 / 9, or 1 / 8 of the total area of ​​the adapter sheet 222.

[0384] In some embodiments, the tab portion 221 is indirectly electrically connected to the first pole column 12 via the adapter sheet 222, so that the weldable area of ​​the conductive portion 22 is the weldable area of ​​the adapter sheet 222, and the projected area of ​​the first weld portion 71 on the projection plane is 20% or more of the area of ​​the weldable area of ​​the adapter sheet 222, along the direction perpendicular to the projection plane.

[0385] In some embodiments, the area of ​​the weldable region of the adapter sheet 222 is 1 / 10 or more of the area of ​​the adapter sheet 222.

[0386] In the above proposed technology, by installing the adapter sheet 222 such that the area of ​​the weldable region of the adapter sheet 222 is 1 / 10 or more of the area of ​​the adapter sheet 222, the adapter sheet 222 can further provide a weldable region sufficient to lay the foundation for improving the current passage capacity and heat diffusion capacity of the first pole column 12. For example, the area of ​​the weldable region of the adapter sheet 222 may be 1 / 10, 1 / 7, 1 / 6, or 1 / 5 of the total area of ​​the adapter sheet 222.

[0387] In some embodiments, as shown in Figure 56, all of the first pole posts 12 of the battery cell 10 are provided on the same wall of the casing 11, so that all the first pole posts 12 are provided on the first wall 110, and welding of the active material coated portion 21 to the corresponding first pole posts 12 can be performed on the same side of the casing 11, thereby simplifying the convenience of operation.

[0388] If all of the first poles 12 of the battery cell 10 are located on the first wall 110, then the first wall 110 may be the wall with the largest area of ​​the casing 11, or the area of ​​the first wall 110 may be smaller than the area of ​​the wall with the largest area of ​​the casing 11.

[0389] In some embodiments, as shown in Figure 56, the casing 11 includes a casing body 111 and a casing cover 112, one end of the casing body 111 being open, the casing cover 112 fitting into the open end of the casing body 111, and the pole posts 12 are all provided at the end of the casing body 111 away from the casing cover 112. The end of the casing body 111 away from the casing cover 112 is understood to refer to the end of the casing body 111 opposite to the casing cover 112. When assembling the battery cell 10, the battery core assembly 2 enters the casing body 111 from the open end, and in this case, the conductive part 22 can be attached in contact with the pole post 12 along the direction in which the battery core assembly 2 enters the casing. In this process, the attachment of the conductive part 22 and the pole post 12 is relatively easy, and assembly efficiency can be improved.

[0390] Selectively, the casing cover 112 may be a flat plate structure, or it may be a housing structure that opens at one end toward the casing body 111.

[0391] In some embodiments, all of the first poles 12 of the battery cell 10 are provided on different walls of the casing 11, thereby facilitating the flexible arrangement of the battery cell 10 with other electrical connection members.

[0392] Specifically, as shown in Figure 56, the casing 11 has a second wall 120, and the second wall 120 and the first wall 110 can be installed facing each other with a gap between them, or at an angle. The second wall 120 has a second mounting hole 114. In this configuration, the multiple first poles 12 can include a first polar pole 12A and a second polar pole 12B with different polarities. Thus, the first polar pole 12A is installed in the mounting hole 113, and the second polar pole 12B, which has the opposite polarity to the first polar pole 12A, is installed in the second mounting hole 114. Similarly, one of the first polarity pole 12A and the second polarity pole 12B is a positive pole and the other is a negative pole, and the second wall 120 does not have to be adjacent to or parallel to the first wall 110, or the second wall 120 does not have to be adjacent to the first wall 110, in which case the second wall 120 may or may not be parallel to the first wall 110, and the first polarity pole 12A and the second polarity pole 12B are provided on different walls of the casing 11, respectively.

[0393] More specifically, all of the first poles 12 of the battery cell 10 are installed on two opposing walls of the casing 11, or all of the first poles 12 of the battery cell 10 are installed on two adjacent walls of the casing 11, and of course, all of the first poles 12 of the battery cell 10 can be installed on three or more walls of the casing 11.

[0394] In this case, the battery core assembly 2 includes one active material coated portion 21 or a plurality of electrically connected active material coated portions 21, and the battery core assembly 2 further includes two conductive portions 22 of opposite polarity, and one of the two conductive portions 22 is electrically connected to the first polarity pole 12A, and the other of the two conductive portions 22 is electrically connected to the second polarity pole 12B, both via a first weld 71. As can be seen from the above, when the battery core assembly 2 includes a plurality of active material coated portions 21, the plurality of active material coated portions 21 may be connected in parallel between the first polarity pole 12A on the first wall 110 and the second polarity pole 12B on the second wall 120 in order to increase the capacity of the battery cell 10.

[0395] The plane on which the cross-section of the second mounting hole 114 is located is used as the projection plane, and along the direction perpendicular to the projection plane, the projected area of ​​the first welded portion 71 corresponding to the second polar pole column 12B on the projection plane is 0.03% or more of the projected area of ​​the second wall 120 on the projection plane. This improves the current passage area and current passage capability of the second polar pole column 12B on the second wall 120, which is advantageous for increasing the charging speed of the battery cell 10. At the same time, it is also advantageous for reducing the current passage temperature of the second polar pole column 12B, which can further reduce the risk of runaway operation of the battery cell 10.

[0396] Clearly, regardless of the number of active material coated portions 21 of the battery core assembly 2, the two conductive portions 22 of each battery core assembly 2 are both electrically connected to the corresponding active material coated portions 21, and one conductive portion 22 of each battery core assembly 2 is electrically connected to the first polarity pole 12A on the first wall 110 via the first weld 71, and the other conductive portion 22 is electrically connected to the second polarity pole 12B on the second wall 120 via another first weld 71.

[0397] Therefore, in the above-mentioned technical proposal of the present application, the arrangement of the first polarity pole 12A and the second polarity pole 12B is relatively flexible, and the battery cell 10 can satisfy different layout requirements.

[0398] In some embodiments, as shown in Figures 70 to 73, the mounting hole 113 includes a plurality of spaced branch holes 1131, the first polarity pole 12A includes a plurality of first pole 12, the plurality of first pole 12 are installed in a one-to-one correspondence with the plurality of branch holes 1131, the battery core assembly 2 includes a plurality of active material coated portions 21, the conductive portion 22 includes a plurality of sub-conductive portions connected in a one-to-one correspondence with the plurality of active material coated portions 21, each sub-conductive portion is electrically connected to one first pole 12 via one sub-weld portion 71.

[0399] The plane on which the cross-section of the mounting hole 113 is located is used as the projection plane, and along the direction perpendicular to the projection plane, the sum of the projected areas of the multiple sub-welded parts 71 on the projection plane is 0.1% or more of the projected area of ​​the first wall 110 on the projection plane, thereby improving the current passing capability of the first polar pole column 12A.

[0400] In this case, the arrangement of the second polarity poles 12B of the battery cell 10 can be set according to the actual requirements. For example, in the example shown in Figure 71, the multiple first poles 12 are installed in a one-to-one correspondence with the multiple branch holes 1131 of the mounting hole 113, and the casing 11 has a second mounting hole 114, which also includes multiple branch holes 1131 installed at intervals, and the second polarity poles 12B include multiple second poles 15, which are installed in a one-to-one correspondence with the multiple branch holes 1131 of the second mounting hole 114, and in this case, the second polarity poles 12B and the first polarity poles 12A may be provided on the same wall or on different walls of the casing 11.

[0401] Of course, in other embodiments of the present application, the mounting hole 113 includes one branch hole 1131, the first polarity pole 12A includes one first pole 12, the second mounting hole 114 also includes one branch hole 1141, and the second polarity pole 12B includes one second pole 15. It is understood that the number of first pole 12s and the number of second pole 15s in a battery cell 10 may be equal or different.

[0402] In some embodiments, all pole columns are provided on two opposing walls of the casing 11, respectively, so that pole columns are installed on the first wall 110 and on the wall of the casing 11 opposite the first wall 110, thereby enabling flexible installation of pole columns.

[0403] In some embodiments, as shown in Figures 67 to 72, the outer contour of the cross-section of the first polar pole column 12A is rectangular, racetrack-shaped, or elliptical, and the cross-section of the first polar pole column 12A may be perpendicular to the axial direction of the mounting hole 113, enabling flexible installation of the outer contour of the first polar pole column 12A. At the same time, the length of the cross-section of the first polar pole column 12A is greater than its width, which is advantageous for the first polar pole column 12A and the first wall 110 to obtain a good match in the longitudinal direction and the width direction of the cross-section of the first polar pole column 12A, for example, the first pole The length of the first wall 110 in the cross-sectional length direction of the polar pole column 12A is greater than the width of the first wall 110 in the cross-sectional width direction of the first polar pole column 12A. This allows for a certain degree of improvement in the cross-sectional area of ​​the first polar pole column 12A that can be placed on the first wall 110. This is advantageous for increasing the cross-sectional area of ​​the first polar pole column 12A within the limited placement area of ​​the first wall 110, which in turn is advantageous for increasing the current passage area of ​​the first polar pole column 12A, improving the current passage capability of the first polar pole column 12A, improving the heat dissipation capability of the first polar pole column 12A, and ultimately for increasing the charging speed of the battery cell 10.

[0404] At the same time, the outer contour of the cross-section of the second polar pole 12B, which has the opposite polarity to the first polar pole 12A, is rectangular, racetrack-shaped, or elliptical. Similarly, it is advantageous for the second polar pole 12B and the corresponding wall of the casing 11 (e.g., the first wall 110 or the second wall 120) to coincide well in the length direction and width direction of the cross-section of the second polar pole 12B. This allows for increased cross-sectional area of ​​the second polar pole 12B by making full use of the effective arrangement area of ​​the corresponding wall of the casing 11, which is advantageous for improving the current passing capability of the second polar pole 12B and for increasing the charging speed of the battery cell 10.

[0405] In the above embodiment of the present application, the rectangle can be understood in a broad sense, and the four sides and angles of the rectangle may be right-angle transitions or rounded-angle transitions, and the racetrack shape is understood to include two parallel line segments and two semicircles connecting these two line segments, as in a racetrack shape. The shape of the cross-sectional outer contour of the second polarity pole 12B of the battery cell 10 may be the same as or different from the shape of the cross-sectional outer contour of the first polarity pole 12A, and the first polarity pole 12A and the second polarity pole 12B may be located on the same wall of the casing 11 or on different walls of the casing 11.

[0406] In some embodiments, as shown in Figures 56, 67 to 72, in the cross-section of the first polar pole column 12A, the dimension of the first polar pole column 12A in the first direction X is more than three times the dimension of the first polar pole column 12A in the second direction Y, the axial directions of the first direction X, the second direction Y, and the mounting hole 113 are perpendicular to each other in pairs, the first polar pole column 12A and the first wall 110 achieve good matching in the first direction X and the second direction Y, the first polar pole column 12A can make full use of the placement area of ​​the first wall 110, the cross-sectional area of ​​the first polar pole column 12A can be increased within the limited placement area of ​​the first wall 110, and the first polar pole column 12A can be configured as a "super large pole column structure", which is advantageous for improving the current passage area, current passage capability, and heat diffusion capability of the first polar pole column 12A.

[0407] As shown in Figures 56, 67-72, in the cross-section of the second polar pole column 12B, the dimension of the second polar pole column 12B in the first direction X is at least three times the dimension of the second polar pole column 12B in the second direction Y, and the polarity of the second polar pole column 12B is opposite to the polarity of the first polar pole column 12A. In this case, the second polar pole column 12B and the first polar pole column 12A may be located on the same wall of the casing 11, or the second polar pole Since column 12B and the first polar pole column 12A are located on two opposing walls of the casing 11, the second polar pole column 12B and the corresponding wall of the casing 11 achieve good matching in the first direction X and the second direction Y, the second polar pole column 12B can make full use of the arrangement area of ​​the corresponding wall of the casing 11, which is advantageous for improving the current passage area, current passage capacity, and heat diffusion capacity of the second polar pole column 12B.

[0408] For example, the dimensions of the first polar pole column 12A in the first direction X may be 3 times, 3.5 times, 4 times, or 4.2 times the dimensions of the first polar pole column 12A in the second direction Y, and the dimensions of the second polar pole column 12B in the first direction X may be 3 times, 3.5 times, 3.7 times, or 4.2 times the dimensions of the second polar pole column 12B in the second direction Y.

[0409] Exemplary, the first direction X is the longitudinal direction of the cross-section of the first polar pole c...

Claims

1. It is a battery cell, A casing assembly (1) includes a casing (11), a pole body (1201) attached to the casing (11), and a first pole (12) including a first cover plate (13) installed on the pole body (1201), A battery core assembly (2) includes an active material coated portion (21) housed within the casing (11) and a conductive portion (22) connected to the active material coated portion (21), which is connected to the pole body (1201) via a first welded portion (71). Includes, The first welded portion (71) is located at least partially on the side of the pole column body (1201) that is separated from the active material coated portion (21), and the first cover plate (13) is used to shield the first welded portion (71). Battery cell.

2. The pole column body (1201) has a first housing groove (12110), the surface of the first pole column (12) facing the active material coated portion (21) is the pole column inner end face (122), the groove opening of the first housing groove (12110) is formed on the pole column inner end face (122), and the first housing groove (12110) has a first end wall (12111) and a first side wall (12113), and the first end wall (12111) is located on the side of the first side wall (12113) away from the active material coated portion (21), at least a portion of the conductive portion (22) is housed in the first housing groove (12110), the first welded portion (71) is provided on the first end wall (12111), and the first cover plate (13) fits with the pole column body (1201) and covers the first welded portion (71). The battery cell according to claim 1.

3. The first end wall (12111) has a first recessed groove (12112), and at least a portion of the first welded portion (71) is located in the first recessed groove (12112). The battery cell (10) according to claim 2.

4. The first pole column (12) has a first groove (126), the surface of the first pole column (12) away from the active material coated portion (21) is the pole column outer end surface (123), the groove opening of the first groove (126) is formed on the pole column outer end surface (123), and the first cover plate seals the groove opening of the first groove. The battery cell (10) according to claim 2.

5. The active material coated portion (21) includes a current collector (211) and an active material layer (212) provided on the current collector (211), the conductive portion (22) includes a tab portion (221) electrically connected to the current collector (211), the tab portion (221) includes a plurality of tab sheets (2211), the plurality of tab sheets (2211) gather at a position close to the current collector (211) to form a first convergence portion (2212), the plurality of tab sheets (2211) gather and connect at a position away from the current collector (211) to form a second convergence portion (2213), the first convergence portion (2212) connects the second convergence portion (2213) and the active material coated portion (21), and at least a part of the second convergence portion (2213) is housed in the first housing groove (12110). The second convergence portion (2213) is connected to the first end wall (12111) via the first weld portion (71). The battery cell according to claim 2.

6. The active material coated portion (21) includes a current collector (211) and an active material layer (212) provided on the current collector (211), the conductive portion (22) includes a tab portion (221) and an adapter sheet (222), the tab portion (221) includes a plurality of tab sheets (2211), the plurality of tab sheets (2211) gather at a position close to the current collector (211) to form a first convergence portion (2212), and the plurality of tabs The sheets (2211) converge and connect at a position away from the current collector (211) to form a second convergence portion (2213), the first convergence portion (2212) connects the second convergence portion (2213) and the active material coating portion (21), the adapter sheet (222) is connected to the second convergence portion (2213), and at least a portion of the adapter sheet (222) is housed in the first housing groove (12110), The adapter sheet (222) is connected to the first end wall (12111) via the first welded portion (71). The battery cell (10) according to claim 2.

7. At least a portion of the first convergence portion (2212) is housed in the first housing groove (12110). The battery cell (10) according to claim 5.

8. The casing (11) has a mounting hole (113), the first pole post (12) is attached to the mounting hole (113), and along the axial direction of the first pole post (12), the depth H1 of the first housing groove (12110) is greater than or equal to the minimum distance H2 from the inner end face (122) of the pole post to the mounting hole (113). The battery cell (10) according to claim 2.

9. The pole column body (1201) has a second housing groove (12120), the surface of the pole column body (1201) away from the active material coated portion (21) is the pole column outer end surface (123), the groove opening of the second housing groove (12120) is formed on the pole column outer end surface (123), and the second housing groove (12120) has a second end wall (12121) adjacent to the active material coated portion (21). The first welded portion (71) is provided on the second end wall (12121), the first cover plate (13) fits with the pole column body (1201), and seals the groove opening of the second housing groove (12120). The battery cell according to claim 1.

10. The conductive portion (22) is located on the side of the second end wall (12121) toward the active material coated portion (21). The battery cell according to claim 9.

11. The second housing groove (12120) communicates with the interior of the casing (11) via the first through hole (12130), the conductive portion (22) is drilled in the first through hole (12130) and at least a portion of it is housed in the second housing groove (12120), and at least a portion of the conductive portion (22) is installed on the side of the second end wall (12121) that is separated from the active material coated portion (21). The battery cell according to claim 9.

12. The second receiving groove (12120) further has a second side wall (12123), the second side wall (12123) is located on the side of the second end wall (12121) away from the active material coated portion (21), and the second side wall (12123) and the second end wall (12121) surround each other to form the second receiving groove (12120), and the first through hole (12130) is opened in the second end wall (12121), The second end wall (12121) has a second recessed groove (12122), and at least a portion of the first welded portion (71) is located within the second recessed groove (12122). The battery cell according to claim 11.

13. The active material coated portion (21) includes a current collector (211) and an active material layer (212) provided on the current collector (211), the conductive portion (22) includes a tab portion (221) electrically connected to the current collector (211), the tab portion (221) includes a plurality of tab sheets (2211), the plurality of tab sheets (2211) gather at a position close to the current collector (211) to form a first convergence portion (2212), the plurality of tab sheets (2211) gather and connect at a position away from the current collector (211) to form a second convergence portion (2213), the first convergence portion (2212) connects the second convergence portion (2213) and the active material coated portion (21), and at least a part of the second convergence portion (2213) is housed in the second housing groove (12120). The second convergence portion (2212) is connected to the second end wall (12121) via the first welded portion (71). The battery cell (10) according to claim 11.

14. The active material coated portion (21) includes a current collector (211) and an active material layer (212) provided on the current collector (211), the conductive portion (22) includes a tab portion (221) and an adapter sheet (222), the tab portion (221) is electrically connected to the current collector (211), the tab portion (221) includes a plurality of tab sheets (2211), and the plurality of tab sheets (2211) converge at a position close to the current collector (211) to form a first convergence portion (2 The first convergence portion (2212) is formed, and the multiple tab sheets (2211) are gathered and connected at a position away from the current collector (211) to form a second convergence portion (2213), the first convergence portion (2212) connects the second convergence portion (2213) and the active material coating portion (21), the adapter sheet (222) is connected to the second convergence portion (2213), and at least a portion of the adapter sheet (222) is housed in the second housing groove (12120), The adapter sheet (222) is connected to the second end wall (12121) via the first welded portion (71). The battery cell (10) according to claim 11.

15. At least a portion of the first convergence portion (2212) is housed in the second housing groove (12120). The battery cell according to claim 13.

16. The pole column body (1201) is provided with a first housing portion (121), the first housing portion (121) has a third housing groove (12140), the surface of the first pole column (12) facing the active material coated portion (21) is the inner end face (122) of the pole column, the third housing groove (12140) is located on the side of the second housing groove (12120) that is close to the active material coated portion (21), and the opening of the third housing groove (12140) is formed on the inner end face (122) of the pole column, the third housing groove (12140) and the second housing groove (12120) are in communication via the first through hole (12130), and at least a part of the first convergence portion (2212) is housed in the third housing groove (12140). The battery cell (10) according to claim 13.

17. The casing assembly (1) further includes a second cover plate (14), the second cover plate (14) covers the outside of the conductive portion (22) located within the first through hole (12130) and the second housing groove (12120). The battery cell according to claim 11.

18. The casing (11) has a mounting hole (113), the first pole post (12) is attached to the mounting hole (113), and along the axial direction of the first pole post (12), the depth H3 of the second housing groove (12120) is greater than or equal to the minimum distance H4 from the outer end face (123) of the pole post to the mounting hole (113). The battery cell (10) according to claim 9.

19. The pole post body (1201) is provided with a first housing portion (121), the first housing portion (121) has a fourth housing groove (12150), the surface of the pole post body (1201) away from the active material coated portion (21) is the pole post outer end surface (123), the groove opening of the fourth housing groove (12150) is formed on the pole post outer end surface (123), the fourth housing groove (12150) communicates with the inside of the casing (11) via a second through hole (12160), and the conductive portion (22) is drilled in the second through hole (12160). The first welded portion (71) is provided on the wall of the second through hole (12160) formed in the first housing portion (121), and the first cover plate (14) fits with the pole column body (1201) and seals the second through hole (12160). The battery cell according to claim 1.

20. The pole column body (1201) includes a first pole column portion (124) and a second pole column portion (125) made of different materials and electrically connected, wherein the second pole column portion (125) is located on the side of the first pole column portion (124) away from the active material coated portion (21), the first housing portion (121) is provided on the first pole column portion (124) or installed on the first pole column portion (124) and the second pole column portion (125), and the first welded portion (71) is installed on the first pole column portion (124). The battery cell (10) according to claim 19.

21. The first cover plate (13) is provided with a second housing portion (134), the second housing portion (134) has a fifth housing groove (1341), the groove opening of the fifth housing groove (1341) is formed on the end face of the end of the first cover plate (13) facing the active material coated portion (21), and the fifth housing groove (1341) has a third end wall (13411) and a third side wall (13412), the third end wall (13411) is located on the side of the third side wall (13412) away from the active material coated portion (21), At least a portion of the first welded portion (71) is housed in the fifth housing groove (1341). The battery cell according to claim 1.

22. The first cover plate (13) is electrically connected to the pole body (1201), or the first cover plate (13) is installed insulated from the pole body (1201). The battery cell (10) according to claim 1.

23. The first cover plate (13) includes a first conductive member (131) and a second conductive member (132) made of different materials, wherein the first conductive member (131) is fitted to the pole body (1201) and electrically connected, and the second conductive member (132) is fitted to the first conductive member (131) and electrically connected. The battery cell (10) according to claim 1.

24. The first conductive member (131) has a second groove (1311), the second conductive member (132) is fitted into the second groove (1311), and the groove opening of the second groove (1311) is formed on the surface of the first conductive member (131) away from the active material coated portion (21) such that the second conductive member (132) is exposed from the groove opening of the second groove (1311). The battery cell (10) according to claim 23.

25. The first cover plate (13) has a stress relief groove (133), and the stress relief groove (133) is located in the outer peripheral region of the first cover plate (13). The battery cell (10) according to claim 23.

26. The present invention further includes a support (3) located within the casing (11) and on the side of the active material coated portion (21) that is close to the first pole column (12), wherein the support (3) has a relief hole (31) to avoid the conductive portion (22), and the conductive portion (22) is adapted to extend through the relief hole (31) toward the side of the support (3) away from the active material coated portion (21). The battery cell (10) according to claim 2.

27. The pole column body (1201) is provided with a first housing section (121), and the support (3) is provided with a guide section (32), the guide section (32) surrounds and forms at least a part of the escape hole (31), and the guide section (32) extends at least partially to the first housing section (121). The battery cell (10) according to claim 26.

28. The escape hole (31) includes a first hole step (311) and a second hole step (312), the second hole step (312) being located on the side of the first hole step (311) closer to the active material coated portion (21), and the cross-sectional area of ​​the second hole step (312) gradually increasing in the direction away from the first hole step (311), the active material coated portion (21) including a current collector (211) and an active material layer (212) provided on the current collector (211), the conductive portion (22) including a tab portion (221) electrically connected to the current collector (211), and the tab portion (221) being a plurality of tab sheets (2211) is included, and a plurality of the tab sheets (2211) gather at a position close to the current collector (211) to form a first convergence section (2212), and a plurality of the tab sheets (2211) gather at a position away from the current collector (211) and connect to form a second convergence section (2213), the first convergence section (2212) connects the second convergence section (2213) and the active material coating section (21), at least a portion of the first convergence section (2212) is housed in the second hole step (312), and the second convergence section (2213) is drilled in the first hole step (311), The battery cell (10) according to claim 26.

29. The support (3) is a single integrated structure, or the support (3) is a separate structure including a removable first support (33) and a second support (34), and the relief hole (31) is defined between the first support (33) and the second support (34). The battery cell (10) according to claim 26.

30. The casing (11) has a first wall (110), a mounting hole (113) is formed in the first wall (110), the pole column body (1201) is installed in the mounting hole (113), the plane on which the cross-section of the mounting hole (113) is located is the projection plane, and along the direction perpendicular to the projection plane, the ratio of the projected area of ​​the first welded portion (71) on the projection plane to the projected area of ​​the first wall (110) on the projection plane is in the range of 0.1% to 1%. The battery cell according to claim 1.

31. The casing (11) has a mounting hole (113), and the pole column body (1201) includes an integrally molded pole column main body (12a), a first position limiting base (12b), and a second position limiting base (12c), wherein the pole column main body (12a) is drilled in the mounting hole (113), the first position limiting base (12b) and the second position limiting base (12c) are installed at both ends of the pole column main body (12a) along the axial direction of the mounting hole (113), the first position limiting base (12b) is fitted to the outside of the casing (11) in a position-limiting manner, and the second position limiting base (12c) is fitted to the inside of the casing (11) in a position-limiting manner, so that the pole column body (1201) is riveted to the casing (11). The battery cell according to claim 1.

32. The aforementioned battery cell (10) is further, Including an outer insulating member (5) that encloses the outside of the casing (11), The battery cell according to claim 1.

33. The casing (11) has a first wall (110), the first wall (110) has a mounting hole (113), the pole body (1201) is installed in the mounting hole (113), the battery cell (10) further includes a patch (9) covering the outside of the first wall (110), the outer insulating member (5) includes an outer insulating film (52) which is an integral diaphragm, the outer insulating film (52) has a connecting portion (51), the connecting portion (51) extends to the outside of the first wall (110) and connects to the patch (9), The battery cell according to claim 32.

34. The minimum distance between the edge of the outer insulating film (52) and the first pole column (12) is 3 mm or more. The battery cell according to claim 33.

35. A battery cell (10) according to any one of claims 1 to 34, battery.

36. Multiple battery cells (10) and A bus member (30) electrically connected to the first poles (12) of at least two of the battery cells (10), wherein the first poles (12) of the same polarity of each of the battery cells (10) are electrically connected to the bus member (30) via a second weld (72), the second weld (72) being formed in the first cover plate (13), and the bus member (30), Includes, The casing (11) includes a first wall (110), the first wall (110) has a mounting hole (113) formed therein, the pole column body (1201) is installed in the mounting hole (113), and in the cross-section of the mounting hole (113), the orthographic area of ​​the second welded portion (72) is 0.2% or more of the orthographic area of ​​the first wall (110). The battery according to claim 35.

37. Along the direction perpendicular to the cross-section of the mounting hole (113), the portion of the bus member (30) that overlaps with the pole column body (12) of the same polarity is the weldable region of the bus member (30). The orthographic projection area of ​​the second welded portion (72) in the cross-section of the mounting hole (113) is 0.2 or more of the area of ​​the weldable region of the bus member (30). The battery according to claim 36.

38. Along the direction perpendicular to the cross-section of the mounting hole (113), the portion of the bus member (30) that overlaps with the first pole column (12) of the same polarity is the weldable region of the bus member (30). The area of ​​the weldable region of the bus member (30) is 20% or more of the orthographic projection area of ​​the bus member (30) in the cross-section of the mounting hole (113). The battery according to claim 36.

39. The area of ​​the weldable region of the bus member (30) is 50% or less of the orthographic projection area of ​​the bus member (30) in the cross-section of the mounting hole (113). The battery according to claim 38.

40. A battery (100) according to claim 35, Electrical device.

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