Battery cell, battery and electric device

Abstract

The embodiment of the invention provides a battery monomer, a battery and a power utilization device. The battery cell includes an electrode assembly, a case, and an electrode terminal. The electrode assembly includes a first tab. The case is used for accommodating the electrode assembly. The electrode terminal is arranged in the shell and electrically connected with the first tab, the electrode terminal is provided with a first through hole, and the first through hole is used for injecting electrolyte into the inner space of the shell. The first through hole for injecting the electrolyte is formed in the electrode terminal, so that the deformation of the shell in the electrolyte injection process can be reduced, the structure of the battery monomer is simplified, and the influence of the first through hole on the strength of the shell is reduced.

Description

[0001] This application is a divisional application of the invention patent application filed on August 22, 2022, with application number 202280007864.9 and titled "Battery Cell, Battery and Electrical Device". Technical Field

[0002] This application relates to the field of battery technology, and more specifically, to a battery cell, a battery, and an electrical device. Background Technology

[0003] Battery cells are widely used in electronic devices such as mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and power tools. Battery cells can include nickel-cadmium battery cells, nickel-metal hydride battery cells, lithium-ion battery cells, and rechargeable alkaline zinc-manganese battery cells, among others.

[0004] In the development of battery technology, simplifying the structure of individual battery cells is a research direction. Summary of the Invention

[0005] This application provides a battery cell, a battery, and an electrical device that simplifies the structure of the battery cell.

[0006] In a first aspect, embodiments of this application provide a battery cell, including an electrode assembly, a housing, and electrode terminals. The electrode assembly includes a first tab. The housing is used to house the electrode assembly. The electrode terminals are disposed in the housing and electrically connected to the first tab. The electrode terminals have a first through hole for injecting electrolyte into the internal space of the housing.

[0007] In the above technical solution, by opening a first through hole on the electrode terminal for injecting electrolyte, the deformation of the casing during the electrolyte injection process can be reduced, the structure of the battery cell can be simplified, and the impact of the first through hole on the casing strength can be reduced.

[0008] In some embodiments, the electrode terminals are electrically connected to the first tab via at least one first solder joint.

[0009] In the above technical solution, the first welding part can reduce the resistance between the electrode terminal and the first tab, thereby improving the overcurrent capacity.

[0010] In some embodiments, the number of first weld portions is one, and the first weld portion extends circumferentially along the first through hole and surrounds at least a portion of the first through hole.

[0011] In the above technical solution, the first welding part can increase the strength of the area around the first through hole of the electrode terminal and reduce the deformation of the electrode terminal under the impact of the electrolyte.

[0012] In some embodiments, the first weld portion surrounds only a portion of the first through hole along the circumferential direction of the first through hole.

[0013] In the above technical solution, the outer periphery of the first through hole is not closed by the first welding part, so the gap between the electrode terminal and the component welded to the electrode terminal will not be blocked by the first welding part. Part of the electrolyte flowing in through the first through hole can pass through the gap, thereby improving the efficiency of electrolyte injection.

[0014] In some embodiments, the angle at which the first weld portion surrounds the first through hole is α, where 180°≤α≤360°.

[0015] α is positively correlated with the current-carrying area of ​​the first weld. The smaller α is, the smaller the current-carrying area of ​​the first weld, and the higher the heat generated when current flows through the first weld. The above technical solution limits α to 180°-360° so that the first weld meets the requirements of the battery cell for current carrying capacity and temperature rise.

[0016] In some embodiments, there are multiple first weld portions, which are spaced apart circumferentially along the first through hole.

[0017] Given a fixed total area, setting multiple first welding sections can reduce the power of a single welding operation and decrease heat generation compared to setting only one first welding section.

[0018] In some embodiments, the circumferential spacing angle β between any two adjacent first weld portions along the first through hole is less than 30°.

[0019] The larger the value of angle β, the sparser the distribution of the multiple first welded parts, and the smaller the total flow area of ​​the multiple first welded parts; the smaller the value of angle β, the denser the distribution of the multiple first welded parts, and the larger the total flow area of ​​the multiple first welded parts. In the embodiments of this application, β is limited to less than 30° to meet the requirements of the battery cell for flow capacity and temperature rise, and to reduce the risk of the first welded parts tearing when the battery cell vibrates.

[0020] In some embodiments, each first weld extends radially along the first through hole.

[0021] In the above technical solution, the first welding part extends radially along the first through hole, which can reduce the circumferential size of the first welding part along the first through hole, so that more first welding parts can be arranged on the outer periphery of the first through hole, thereby improving the current carrying capacity and reducing heat generation.

[0022] In some embodiments, the depth of the first weld portion in the axial direction of the first through hole is h; the minimum distance between the first weld portion and the first through hole in the radial direction is d. d and h satisfy: 0.1≤h / d≤0.6.

[0023] A larger h value results in higher welding power, higher heat generation during welding, greater thermal stress in the area near the first through-hole, and greater deformation of the first through-hole. Conversely, a smaller d value leads to more heat being conducted to the area near the first through-hole during welding, resulting in greater thermal stress and deformation of the first through-hole. If h / d is too large, it will cause severe deformation of the first through-hole, making it difficult for the injection head to fit properly and affecting injection efficiency. The above technical solution limits the value of h / d to less than or equal to 0.6 to reduce the thermal stress in the area near the first through-hole, minimize deformation, and facilitate the fit between the injection head and the first through-hole.

[0024] The smaller the value of h, the lower the current-carrying capacity and strength of the first weld, and the higher the risk of tearing of the first weld when the battery cell vibrates. The larger the value of d, the smaller the area of ​​the electrode terminal that can be used for welding, and the more limited the current-carrying capacity and strength of the first weld. If h / d is too small, the current-carrying capacity and strength of the first weld will be insufficient. The above technical solution limits the value of h / d to greater than or equal to 0.1 to ensure that the current-carrying capacity and strength of the first weld meet the requirements.

[0025] In some embodiments, d and h satisfy: 0.2≤h / d≤0.5.

[0026] In some embodiments, 1.6mm ≤ d ≤ 5.5mm.

[0027] If d is too small, excessive heat will be conducted to the area near the first through hole during welding, resulting in excessive thermal stress in that area. This will cause severe deformation of the first through hole, making it difficult for the injection head to mate with it and affecting injection efficiency. If d is too large, the area of ​​the electrode terminal suitable for welding will be too small, leading to insufficient flow capacity and strength of the first welded part. The above technical solution limits the value of d to 1.6mm-5.5mm to reduce deformation of the first through hole, facilitate the mating of the injection head with the first through hole, and ensure that the flow capacity and strength of the first welded part meet the requirements.

[0028] In some embodiments, the electrode assembly is a wound structure, and the electrode assembly has a second through hole at the center of the winding. The first through hole communicates with the second through hole so that electrolyte injected through the first through hole can flow into the second through hole.

[0029] In the above technical solution, during the liquid injection process, the electrolyte can flow into the second through hole through the first through hole, and the electrolyte flowing into the second through hole can wet the electrode assembly from the inside, thereby improving the wetting efficiency of the electrode assembly.

[0030] In some embodiments, the projection of the first through hole at least partially overlaps with the projection of the second through hole in the axial direction of the first through hole.

[0031] In the above technical solution, the first through hole and the second through hole are opposite each other along the axial direction of the first through hole. The electrolyte passing through the first through hole can enter the second through hole without changing its flow direction, thereby improving the wetting efficiency of the electrode assembly.

[0032] In some embodiments, the projection of the second through hole is larger than the projection of the first through hole in the axial direction of the first through hole.

[0033] In the above technical solution, compared with the first through hole, the second through hole has a larger cross-sectional area, which allows the second through hole to accommodate more electrolyte, thus helping to improve the efficiency of electrolyte wetting the electrode assembly from the inside.

[0034] In some embodiments, the projection of the first through hole lies within the projection of the second through hole along its axial direction.

[0035] The above technical solution allows the solid part of the electrode assembly to avoid the first through hole, reducing the direct impact of the electrolyte on the electrode assembly and lowering the risk of electrode assembly deformation.

[0036] In some embodiments, the diameter of the first through hole is D1, the diameter of the second through hole is D2, and D1 and D2 satisfy: 65%≤D1 / D2≤95%.

[0037] A larger D1 indicates higher electrolyte injection efficiency, shorter electrolyte filling time, less electrolyte that can wet the electrode assembly during injection, and a smaller total electrolyte injection volume. A smaller D2 indicates a smaller hole wall area for the second through-hole, resulting in lower electrolyte wetting efficiency from the electrode assembly. If D1 / D2 is too large, it will lead to insufficient electrolyte injection, affecting the cycle life of the battery cells. The above technical solution limits the value of D1 / D2 to less than or equal to 95% to ensure the required electrolyte injection volume.

[0038] A smaller D1 value results in lower electrolyte injection efficiency and a longer time to fill the electrolyte chamber; a larger D2 value results in higher electrolyte wetting efficiency from the electrode assembly. If D1 / D2 is too small, it will cause a longer injection time, leading to lower product production efficiency. Furthermore, a larger D2 value results in a smaller electrode assembly capacity, lower internal space utilization of the battery cell, and lower energy density of the battery cell. The above technical solution limits the value of D1 / D2 to greater than or equal to 65% to improve injection efficiency and reduce the energy density loss of the battery cell caused by the second through-hole.

[0039] In some embodiments, D2 ≥ D1 + 0.2 mm.

[0040] During battery cell assembly, assembly errors may cause the electrode assembly to shift, resulting in the first through-hole aligning with the solid portion of the electrode assembly. This can lead to the electrode assembly being impacted by the electrolyte. The aforementioned technical solution ensures that D2 ≥ D1 + 0.2 mm, providing a margin for offset of the electrode assembly, reducing the risk of the solid portion of the electrode assembly aligning with the first through-hole, minimizing direct impact of the electrolyte on the electrode assembly, and reducing the risk of electrode assembly deformation.

[0041] In some embodiments, the battery cell further includes a current collector for electrically connecting the electrode terminals and the first tab. The current collector includes a third through-hole, at least a portion of which is disposed between the first through-hole and the second through-hole.

[0042] In the above technical solution, by setting a third through hole, the current collector can avoid the electrolyte flowing in through the first through hole, thereby reducing the obstruction of the current collector to the electrolyte during the liquid injection process, allowing the electrolyte to pass smoothly through the third through hole and flow into the second through hole, thus improving the wetting efficiency of the electrode assembly.

[0043] In some embodiments, the projection of the third through hole is smaller than the projection of the second through hole in the axial direction of the first through hole.

[0044] In the above technical solution, compared with the third through hole, the second through hole has a larger cross-sectional area, which allows the electrolyte passing through the third through hole to flow into the second through hole quickly, thus helping to improve the efficiency of electrolyte wetting the electrode assembly from the inside.

[0045] In some embodiments, the projection of the third through hole is larger than the projection of the first through hole in the axial direction of the first through hole.

[0046] In the above technical solution, compared with the first through hole, the third through hole has a larger cross-sectional area, which can reduce the risk of the current collector component blocking the first through hole, and allow the electrolyte to pass smoothly through the third through hole and enter the second through hole, thereby improving the efficiency of the electrolyte wetting the electrode assembly from the inside.

[0047] In some embodiments, the projection of the first through hole lies within the projection of the third through hole along its axial direction.

[0048] The above technical solution can reduce the risk of the current collector blocking the first through hole, allowing the electrolyte to flow smoothly into the casing, and can also reduce the impact on the current collector and reduce the risk of cracking at the connection between the current collector and the electrode terminal.

[0049] In some embodiments, the projection of the third through hole lies within the projection of the second through hole along the axial direction of the first through hole.

[0050] The above technical solution can reduce the obstruction of the third through hole by the solid part of the electrode assembly, so that the electrolyte can flow smoothly into the second through hole.

[0051] In some embodiments, the first through hole, the second through hole, and the third through hole are coaxially arranged.

[0052] In the above technical solution, the three through holes are arranged coaxially, which can make the electrolyte flow more smoothly and reduce the impact of the electrolyte on the current collector and electrode assembly.

[0053] In some embodiments, the electrode terminal includes a sealing plate and a terminal body, the terminal body having a first through hole, and the sealing plate being connected to the terminal body and used to seal the first through hole.

[0054] In the above technical solution, after the process related to the first through hole is completed, the sealing plate is connected to the terminal body to reduce the risk of electrolyte leakage through the first through hole and improve the sealing performance.

[0055] In some embodiments, the terminal body includes a recess and a connecting portion located on the side of the recess facing the electrode assembly, a first through hole passing through the connecting portion, and the connecting portion achieving electrical connection with the first electrode tab via at least one first weld portion. At least a portion of the sealing plate is accommodated in the recess.

[0056] In the above technical solution, by creating a recess in the terminal body, the thickness of the connection portion can be reduced, thereby reducing the welding power required for welding, lowering the risk of other components being burned, and improving safety. The recess can also provide space for the sealing plate, thereby reducing the size of the sealing plate protruding from the terminal body, reducing the space occupied by the electrode terminals, and increasing the energy density of the battery cell.

[0057] In some embodiments, the housing includes a cylindrical body and a cover connected to the cylindrical body. The cylindrical body is disposed around the outer periphery of the electrode assembly, and the cover is provided with an electrode lead-out hole, and an electrode terminal is disposed in the electrode lead-out hole.

[0058] In some embodiments, the cover and the cylinder are integrally formed, eliminating the need for a connection process between the cover and the cylinder. When the cover and the cylinder are electrically connected to the positive or negative electrode of the electrode assembly, the resistance at the connection point is low due to the integral structure, thereby improving current carrying capacity. The cover can be used to connect to external components (such as busbars). When a battery cell is subjected to external impact, the external component may pull on the cover, causing force to be applied to the connection point between the cover and the cylinder. The above technical solution integrates the cover and the cylinder, thereby increasing the strength of the connection point and reducing the risk of connection failure.

[0059] In some embodiments, the electrode assembly further includes a second tab, which has the opposite polarity to the first tab, and is electrically connected to the cover.

[0060] In the above technical solution, one of the cover and the electrode terminal can serve as the positive output terminal of the battery cell, and the other can serve as the negative output terminal of the battery cell. This technical solution places the positive and negative output terminals on the same side of the battery cell, which simplifies the connection process between multiple battery cells.

[0061] In some embodiments, the first tab is located at the end of the electrode assembly facing the electrode terminal, and the second tab is located at the end of the electrode assembly away from the electrode terminal.

[0062] In the above technical solution, the first electrode and the second electrode are respectively located at opposite ends of the electrode assembly, which can increase the distance between the first electrode and the second electrode, reduce the risk of the first electrode and the second electrode being connected, and improve safety.

[0063] In some embodiments, the second electrode is a negative electrode, and the base material of the housing is steel.

[0064] In the above technical solution, the casing is electrically connected to the negative electrode tab, meaning the casing is in a low potential state. The steel casing is less susceptible to corrosion by the electrolyte in this low potential state.

[0065] In some embodiments, the cylinder has an opening at one end away from the cover, and the battery cell also includes a cover for closing the opening.

[0066] Secondly, embodiments of this application provide a battery comprising a plurality of battery cells according to any of the embodiments of the first aspect.

[0067] Thirdly, embodiments of this application provide an electrical device including a battery as described in the second aspect, the battery being used to provide electrical energy. Attached Figure Description

[0068] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0069] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments; Figure 2 Explosion diagrams of batteries provided for some embodiments of this application; Figure 3 for Figure 2 The diagram shows the structure of the battery module. Figure 4 This is an exploded schematic diagram of a battery cell provided in some embodiments of this application; Figure 5 A cross-sectional schematic diagram of a battery cell provided in some embodiments of this application; Figure 6 for Figure 5 A partially enlarged schematic diagram of a single battery cell; Figure 7 for Figure 6 Enlarged view at box B; Figure 8 A schematic diagram of the electrode terminals of a battery cell provided in some embodiments of this application; Figure 9 for Figure 7 Enlarged view at point C in the circle; Figure 10 A schematic diagram of the terminal body of the electrode terminal of a battery cell provided in some embodiments of this application; Figure 11 A schematic diagram of the terminal body of the electrode terminal of a battery cell provided in other embodiments of this application; Figure 12 A schematic diagram of the terminal body of the electrode terminal of a battery cell provided in some embodiments of this application; Figure 13 Partial cross-sectional schematic diagram of a battery cell provided for other embodiments of this application; Figure 14 Partial cross-sectional schematic diagram of a battery cell provided for other embodiments of this application; Figure 15 This is a cross-sectional schematic diagram of a battery cell provided for other embodiments of this application.

[0070] The accompanying drawings are not drawn to scale. Detailed Implementation

[0071] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0072] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0073] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0074] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0075] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0076] In the embodiments of this application, the same reference numerals denote 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 thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0077] In this application, "multiple" means two or more (including two).

[0078] In this application, the term "parallel" includes not only the case of absolute parallelism, but also the case of approximate parallelism as commonly understood in engineering; similarly, "perpendicular" includes not only the case of absolute perpendicularity, but also the case of approximate perpendicularity as commonly understood in engineering.

[0079] In this application, the battery cell may include lithium-ion secondary battery cell, lithium-ion primary battery cell, lithium-sulfur battery cell, sodium lithium-ion battery cell, sodium-ion battery cell, or magnesium-ion battery cell, etc., and the embodiments of this application are not limited thereto.

[0080] The battery mentioned in the embodiments of this application refers to a single physical module comprising one or more battery cells to provide higher voltage and capacity. For example, the battery mentioned in this application may include a battery module or a battery pack. A battery generally includes a housing for encapsulating one or more battery cells. The housing prevents liquids or other foreign matter from affecting the charging or discharging of the battery cells.

[0081] A battery cell includes electrode components and an electrolyte. The electrode components include a positive electrode, a negative electrode, and a separator. The battery cell primarily functions by the movement of metal ions between the positive and negative electrode components. The positive electrode includes a positive current collector and a positive active material layer, with the active material layer coated on the surface of the current collector. The current collector includes a positive current-collecting section and a positive electrode tab; the current-collecting section is coated with the positive active material layer, while the positive electrode tab is not. Taking a lithium-ion battery as an example, the positive current collector can be made of aluminum, and the positive active material layer includes the positive active material, which can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode includes a negative current collector and a negative active material layer, with the active material layer coated on the surface of the current collector. The current collector includes a negative current-collecting section and a negative electrode tab; the current-collecting section is coated with the negative active material layer, while the negative electrode tab is not. The negative electrode current collector can be made of copper, and the negative electrode active material layer includes the negative electrode active material, which can be carbon or silicon, etc. The separator can be made of PP (polypropylene) or PE (polyethylene), etc.

[0082] The battery cell also includes a housing for accommodating electrode assemblies and electrode terminals disposed on the housing, the electrode terminals being used for electrical connection to the electrode assemblies to enable charging and discharging of the electrode assemblies.

[0083] During battery manufacturing, electrolyte needs to be injected into the casing. To achieve this injection, the inventors attempted to create an injection hole in the casing. When injection is needed, the injection head of the injection device presses against the casing, and then injects the electrolyte into the casing through the injection hole.

[0084] However, the inventors discovered that creating an injection hole in the casing would complicate the casing's structure; the injection hole would occupy space in the casing, affecting the installation of other components. Compared to the electrode terminals, the casing is thinner and has lower strength; during injection, the casing may deform due to the pressure from the injection head, potentially causing defects in the shape of the battery cell.

[0085] In view of this, the present application provides a technical solution that reduces the deformation of the casing during the electrolyte injection process by opening a through hole on the electrode terminal for injecting electrolyte, simplifies the structure of the battery cell, and reduces the impact of the first through hole on the casing strength.

[0086] The technical solutions described in the embodiments of this application are applicable to batteries and electrical devices that use batteries.

[0087] Electrical devices can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, etc. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This application does not impose any special limitations on the above-mentioned electrical devices.

[0088] For ease of explanation, the following embodiments will use a vehicle as an example of an electrical device.

[0089] Figure 1 The diagram shows the structural features of a vehicle as provided in some embodiments of this application. Figure 1 As shown, a battery 2 is installed inside the vehicle 1. The battery 2 can be located at the bottom, front, or rear of the vehicle 1. The battery 2 can be used to power the vehicle 1; for example, the battery 2 can serve as the operating power source for the vehicle 1.

[0090] Vehicle 1 may also include controller 3 and motor 4. Controller 3 is used to control battery 2 to supply power to motor 4, for example, for the power needs of vehicle 1 during start-up, navigation and driving.

[0091] In some embodiments of this application, the battery 2 can not only serve as the operating power source for the vehicle 1, but also as the driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0092] Figure 2 This is a schematic diagram of a battery explosion provided for some embodiments of this application. For example... Figure 2 As shown, battery 2 includes a housing 5 and battery cells ( Figure 2 (Not shown), the battery cells are housed inside the casing 5.

[0093] The housing 5 is used to house individual battery cells, and the housing 5 can have various structures. In some embodiments, the housing 5 may include a first housing portion 5a and a second housing portion 5b, which overlap each other, and together define a housing space 5c for housing the individual battery cells. The second housing portion 5b may be a hollow structure with one end open, and the first housing portion 5a may be a plate-like structure, with the first housing portion 5a covering the open side of the second housing portion 5b to form a housing 5 with the housing space 5c; alternatively, both the first housing portion 5a and the second housing portion 5b may be hollow structures with one side open, with the open side of the first housing portion 5a covering the open side of the second housing portion 5b to form a housing 5 with the housing space 5c. Of course, the first housing portion 5a and the second housing portion 5b can have various shapes, such as cylinders, cuboids, etc.

[0094] To improve the sealing performance after the first housing part 5a and the second housing part 5b are connected, a sealing element, such as sealant or sealing ring, can also be provided between the first housing part 5a and the second housing part 5b.

[0095] Assuming that the first box section 5a covers the top of the second box section 5b, the first box section 5a can also be called the upper box cover, and the second box section 5b can also be called the lower box.

[0096] In battery 2, there can be one or more individual battery cells. If there are multiple individual battery cells, they can be connected in series, parallel, or in a mixed configuration. A mixed configuration means that multiple individual battery cells are connected in both series and parallel configurations. Multiple individual battery cells can be directly connected in series, parallel, or in a mixed configuration and then housed within housing 5. Alternatively, multiple individual battery cells can first be connected in series, parallel, or in a mixed configuration to form battery module 6, and then multiple battery modules 6 can be connected in series, parallel, or in a mixed configuration to form a whole and housed within housing 5.

[0097] Figure 3 for Figure 2 The diagram shows the structure of the battery module.

[0098] In some embodiments, such as Figure 3 As shown, there are multiple battery cells 7, which are first connected in series, parallel, or a combination of both to form a battery module 6. These battery modules 6 are then connected in series, parallel, or a combination of both to form a whole, which is housed within the casing.

[0099] Multiple battery cells 7 in battery module 6 can be electrically connected through busbar components 8 to achieve parallel, series, or mixed connection of multiple battery cells 7 in battery module 6. There can be one or more busbar components, and each busbar component 8 is used to electrically connect at least two battery cells.

[0100] Figure 4This is an exploded schematic diagram of a battery cell provided in some embodiments of this application; Figure 5 A cross-sectional schematic diagram of a battery cell provided in some embodiments of this application; Figure 6 for Figure 5 A partially enlarged schematic diagram of a single battery cell; Figure 7 for Figure 6 Enlarged view of box B.

[0101] like Figures 4 to 7 As shown, the battery cell 7 in this embodiment includes an electrode assembly 10, a housing 20, and electrode terminals 30. The electrode assembly 10 includes a first tab 11. The housing 20 is used to house the electrode assembly 10. The electrode terminals 30 are disposed on the housing 20 and electrically connected to the first tab 11. The electrode terminals 30 are provided with a first through hole 323 for injecting electrolyte into the internal space of the housing 20.

[0102] The electrode assembly 10 includes a first electrode and a second electrode with opposite polarities. One of the first electrode and the second electrode is a positive electrode, and the other is a negative electrode. Exemplarily, the electrode assembly 10 generates electrical energy through oxidation and reduction reactions during the insertion / extraction of ions in the positive and negative electrode plates. Optionally, the electrode assembly 10 further includes a separator for insulating and isolating the first electrode and the second electrode.

[0103] In some examples, the first electrode, the second electrode, and the spacer are all strip structures, wound together around the central axis A to form a wound structure. The wound structure can be cylindrical, flat, or other shapes. In other examples, the electrode assembly 10 can also be a stacked structure formed by arranging the first electrode, the spacer, and the second electrode in layers.

[0104] The first tab 11 can be the portion of the first electrode sheet that is not coated with the active material layer. The first tab 11 can be a positive tab or a negative tab.

[0105] The housing 20 is a hollow structure, forming an interior space for accommodating the electrode assembly 10. The housing 20 can have various shapes and sizes, such as cuboid, cylindrical, or hexagonal prism. The shape of the housing 20 can be determined based on the specific shape of the electrode assembly 10. For example, if the electrode assembly 10 is cylindrical, a cylindrical housing can be used; if the electrode assembly 10 is cuboid, a cuboid housing can be used. Optionally, both the electrode assembly 10 and the housing 20 can be cylindrical.

[0106] The shell 20 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc. This application embodiment does not impose any special restrictions on this.

[0107] The casing 20 can be positively charged, negatively charged, or uncharged.

[0108] The electrode terminal 30 can be disposed insulatedly on the housing 20 or electrically connected to the housing 20. This application embodiment does not limit this, as long as the positive electrode and the negative electrode are prevented from conducting.

[0109] The electrode terminal 30 can be directly connected to the first electrode tab 11 to achieve an electrical connection between the electrode terminal 30 and the first electrode tab 11. Exemplarily, the electrode terminal 30 can be connected to the first electrode tab 11 by bonding, abutting, snapping, welding or other means.

[0110] Alternatively, the electrode terminal 30 can also be indirectly connected to the first tab 11 via other conductive components to achieve an electrical connection between the electrode terminal 30 and the first tab 11. For example, a conductive component can be simultaneously connected to both the first tab 11 and the electrode terminal 30 to achieve an electrical connection between the electrode terminal 30 and the first tab 11.

[0111] The electrode terminal 30 can serve as the output electrode of the battery cell 7, which can electrically connect the battery cell 7 to an external circuit to enable charging and discharging of the battery cell 7. Optionally, the electrode terminal 30 is used to connect to a busbar component to enable electrical connection between the battery cells 7.

[0112] There can be one or more first through holes 323.

[0113] During the molding process of the battery cell 7, the first through hole 323 connects the space outside the housing 20 with the internal space of the housing 20. When electrolyte injection is required, the injection head of the injection device presses against the electrode terminal 30, and then the injection head injects electrolyte into the housing 20 through the first through hole 323.

[0114] By opening a first through hole 323 for injecting electrolyte on the electrode terminal 30, the deformation of the housing 20 during the electrolyte injection process can be reduced, the structure of the battery cell 7 can be simplified, and the influence of the first through hole 323 on the strength of the housing 20 can be reduced.

[0115] In some embodiments, the first through-hole 323 may also be applied to other processes, such as the formation process.

[0116] During the formation process of the battery cell 7, gas is generated inside the casing 20. The first through hole 323 can also be used to connect with an external negative pressure device to extract the gas inside the casing 20.

[0117] In some embodiments, the electrode assembly 10 includes a main body 12, a first tab 11, and a second tab 13, the first tab 11 and the second tab 13 protruding from the main body 12. The first tab 11 is the portion of the first electrode sheet that is not coated with an active material layer, and the second tab 13 is the portion of the second electrode sheet that is not coated with an active material layer.

[0118] The first tab 11 and the second tab 13 can extend from the same side of the main body 12, or they can extend from opposite sides respectively. For example, the first tab 11 is located at the end of the electrode assembly 10 facing the electrode terminal 30, and the second tab 13 is located at the end of the electrode assembly 10 away from the electrode terminal 30.

[0119] In some embodiments, the first tab 11 is wound multiple times around the central axis A of the electrode assembly 10; in other words, the first tab 11 includes multiple tab layers. After winding, the first tab 11 is generally cylindrical, with gaps between adjacent tab layers. Embodiments of this application can process the first tab 11 to reduce the gaps between tab layers, facilitating connection between the first tab 11 and other components. For example, embodiments of this application can flatten the first tab 11 to gather and aggregate the end regions of the first tab 11 away from the main body 12; the flattening process forms a dense end face at the end of the first tab 11 away from the main body 12, reducing the gaps between tab layers and facilitating connection between the first tab 11 and other components. Alternatively, embodiments of this application can also fill the spaces between adjacent tab layers with conductive material to reduce the gaps between tab layers.

[0120] In some embodiments, the second tab 13 is wound around the central axis A of the electrode assembly 10 multiple times, and the second tab 13 includes multiple tab layers. Exemplarily, the second tab 13 is also flattened to reduce the gaps between the tab layers of the second tab 13.

[0121] The central axis A of the electrode assembly 10 is a virtual straight line. The first electrode, the second electrode, and the separator can be wound with the central axis A as a reference.

[0122] In some embodiments, the housing 20 includes a cylindrical body 21 and a cover 22 connected to the cylindrical body 21. The cylindrical body 21 is disposed around the outer periphery of the electrode assembly 10, and the cover 22 is provided with an electrode lead-out hole 221, and an electrode terminal 30 is disposed in the electrode lead-out hole 221.

[0123] The cover 22 and the cylinder 21 can be an integrally formed structure, that is, the shell 20 is a one-piece component. Of course, the cover 22 and the cylinder 21 can also be two separate components, which are then connected together by welding, riveting, bonding or other methods.

[0124] Electrode lead-out hole 221 penetrates the cover 22 to facilitate the lead-out of electrical energy in electrode assembly 10 to the outside of housing 20.

[0125] The central axis A is a virtual straight line. In some embodiments, the central axis A may pass through the electrode lead-out hole 221. The central axis A of the electrode assembly 10 may or may not coincide with the axis of the electrode lead-out hole 221. In other embodiments, the central axis A may not pass through the electrode lead-out hole 221.

[0126] Electrode terminal 30 is used to mate with electrode lead-out hole 221 to cover electrode lead-out hole 221. Electrode terminal 30 may or may not extend into electrode lead-out hole 221. Electrode terminal 30 is fixed to cover 22. Electrode terminal 30 may be fixed as a whole to the outside of cover 22, or it may extend into the inside of housing 20 through electrode lead-out hole 221.

[0127] In some embodiments, the cylinder 21 is a cylindrical body, and the cover 22 is a circular plate-like structure. In other embodiments, the cylinder 21 may be a square cylinder, and the cover 22 may be a square plate-like structure.

[0128] In some embodiments, the cover 22 and the cylinder 21 are integrally formed. This eliminates the need for the connection process between the cover 22 and the cylinder 21.

[0129] When the cover 22 and the cylinder 21 are electrically connected to the positive or negative terminal of the electrode assembly 10, the resistance at the connection between the cover 22 and the cylinder 21 is small due to the integral structure of the connection, thereby improving the current carrying capacity. The cover 22 can be used to connect to external components (such as busbar components). When the battery cell is subjected to external impact, the external component may pull on the cover 22, causing the connection between the cover 22 and the cylinder 21 to be subjected to force. The above technical solution integrates the cover 22 and the cylinder 21, thereby improving the strength of the connection between the cover 22 and the cylinder 21 and reducing the risk of connection failure.

[0130] In some embodiments, the housing 20 may be formed by a stretching process.

[0131] In some embodiments, the cylinder 21 has an opening 211 at one end away from the cover 22, and the battery cell 7 also includes a cover plate 50 for closing the opening 211.

[0132] The cover plate 50 is fitted onto the opening of the cylinder 21 to seal the opening. The cover plate 50 can have various structures, such as a plate-shaped structure.

[0133] In some embodiments, the cover plate 50 may be a circular cover plate, a rectangular cover plate, a square cover plate, a hexagonal cover plate, or a cover plate of other shapes.

[0134] In some embodiments, the cover plate 50 is welded to the cylinder 21.

[0135] In some embodiments, the cover 22 is circular, and the electrode assembly 10 is cylindrical; the central axis A coincides with the axis of the electrode lead-out hole 221. This embodiment does not require the central axis A to be completely coincident with the axis of the electrode lead-out hole 221; a process-permissible deviation may exist between them.

[0136] In this embodiment, the electrode lead-out hole 221 is generally located in the middle of the cover 22, and correspondingly, the electrode terminal 30 is also installed in the middle of the cover 22. When multiple battery cells 7 are assembled into a group, the positioning accuracy requirements of the electrode terminal 30 can be reduced, and the assembly process can be simplified.

[0137] For example, the axis of the electrode lead-out hole 221 coincides with the axis of the cover 22, and the cover 22 is an annular structure arranged around the axis of the electrode lead-out hole 221.

[0138] For example, the axis of the electrode terminal 30 coincides with the axis of the electrode lead-out hole 221.

[0139] In other embodiments, the cover 22 may also be rectangular, and the electrode assembly 10 may be flat. The electrode lead-out hole 221 may be located near the end of the cover 22 along its length.

[0140] In some embodiments, the axis of the first through hole 323 coincides with the axis of the electrode lead-out hole 221.

[0141] In some embodiments, the electrode assembly 10 further includes a second tab 13, which has the opposite polarity to the first tab 11, and is electrically connected to the cover 22.

[0142] The cover 22 itself can serve as an output electrode of one of the battery cells 7, thereby eliminating the need for a traditional electrode terminal 30 and simplifying the structure of the battery cell 7. When multiple battery cells 7 are assembled into a group, the cover 22 can be electrically connected to the busbar component, which can increase the current flow area and make the structural design of the busbar component more flexible.

[0143] In some embodiments, the cylinder 21 is used to connect the second tab 13 and the cover 22 so that the second tab 13 and the cover 22 are electrically connected.

[0144] The cylinder 21 can be directly electrically connected to the second electrode 13, or it can be electrically connected to the second electrode 13 through other components. For example, the second electrode 13 is electrically connected to the cylinder 21 through the cover plate 50.

[0145] The cover 22 and the electrode terminal 30 have different polarities. In this case, one of the cover 22 and the electrode terminal 30 can serve as the positive output terminal of the battery cell 7, and the other can serve as the negative output terminal of the battery cell 7. In this embodiment, the positive and negative output terminals are located on the same side of the battery cell 7, which simplifies the connection process between multiple battery cells 7.

[0146] The cover 22 can be used for electrical connection of the busbar component. The inventors attempted to create a first through hole in the cover, but this would reduce the connection area between the cover and the busbar component, decreasing the current flow area and making it difficult to meet the requirements of the battery cell for current flow capacity and temperature rise during fast charging. Therefore, the inventors created a first through hole 323 for liquid injection on the electrode terminal 30 to increase the connection area between the cover 22 and the busbar component.

[0147] In some embodiments, the first tab 11 is located at the end of the electrode assembly 10 facing the electrode terminal 30, and the second tab 13 is located at the end of the electrode assembly 10 away from the electrode terminal 30.

[0148] By placing the first tab 11 and the second tab 13 at opposite ends of the electrode assembly 10, the distance between the first tab 11 and the second tab 13 can be increased, reducing the risk of the first tab 11 and the second tab 13 becoming conductive and improving safety.

[0149] In some embodiments, the second tab 13 is the negative tab, and the base material of the housing 20 is steel. The base material is the main component in the material composition of the housing 20.

[0150] The housing 20 is electrically connected to the negative electrode tab, meaning the housing 20 is in a low potential state. The steel housing 20 is less susceptible to corrosion by the electrolyte in this low potential state.

[0151] The electrode lead-out hole 221 in this embodiment is formed after the housing 20 is stretched and formed.

[0152] The inventors attempted to roll-press the open end of the cylinder to fold it inward and form a flange structure, which then pressed against the cover plate to secure it. The inventors then mounted electrode terminals onto the cover plate, using the flange structure and electrode terminals as the two output poles of the battery cell. However, the larger the flange structure, the higher the risk of curling and wrinkling after molding. If curling and wrinkling occur, the surface of the flange structure will be uneven, leading to poor welding when it is welded to external busbar components. Therefore, the size of the flange structure is relatively limited, resulting in insufficient current carrying capacity of the battery cell.

[0153] In this embodiment, an electrode lead-out hole 221 for mounting the electrode terminal 30 is formed on the cover 22 using an opening process, so that the positive and negative output terminals are located at the end of the battery cell 7 away from the opening of the cylinder 21. The cover 22 is formed during the molding process of the shell 20. The opening of the electrode lead-out hole 221 can also improve the flatness and the connection strength between the cover 22 and the busbar component. At the same time, the flatness of the cover 22 is not constrained by its own size, so the cover 22 can have a larger size, thereby improving the current carrying capacity of the battery cell 7.

[0154] In some embodiments, the electrode terminal 30 is electrically connected to the first tab 11 via at least one first solder part W1.

[0155] The electrode terminal 30 is welded to other components to form a first welded portion W1. Current is conducted between the electrode terminal 30 and the first tab 11 through the first welded portion W1.

[0156] In some examples, the electrode terminal 30 can be directly welded to the first tab 11 to form a first welded portion W1. For example, a portion of the electrode terminal 30 and a portion of the first tab 11 melt and form a molten pool, which solidifies to form the first welded portion W1.

[0157] In other alternative examples, the electrode terminal 30 is welded to other components (such as the current collector described later) connected to the first tab 11 to form the first weld portion W1. For example, a portion of the electrode terminal 30 and a portion of the current collector melt to form a molten pool, which solidifies to form the first weld portion W1.

[0158] The embodiments of this application do not impose special limitations on the shape, position, depth, or number of the first welding portion W1. For example, the shape of the first welding portion W1 can be straight, rectangular, annular, spiral, V-shaped, or other shapes. There can be one or more first welding portions W1.

[0159] The first welding part W1 can reduce the resistance between the electrode terminal 30 and the first tab 11, thereby improving the overcurrent capacity.

[0160] Figure 8 A schematic diagram of the electrode terminals of a battery cell provided in some embodiments of this application; Figure 9 for Figure 7 Enlarged view at point C in the circle; Figure 10 This is a schematic diagram of the terminal body of the electrode terminal of a battery cell provided in some embodiments of this application.

[0161] Please refer to the above as well. Figures 6 to 10In some embodiments, the electrode terminal 30 includes a sealing plate 33 and a terminal body 34. The terminal body 34 is provided with a first through hole 323. The sealing plate 33 is connected to the terminal body 34 and is used to seal the first through hole 323.

[0162] After the process associated with the first through-hole 323 is completed, the sealing plate 33 is connected to the terminal body 34 to reduce the risk of electrolyte leakage through the first through-hole 323 and improve sealing performance.

[0163] In some embodiments, the terminal body 34 includes a recess 31 and a connecting portion 32 located on the side of the recess 31 facing the electrode assembly 10. A first through hole 323 passes through the connecting portion 32, and the connecting portion 32 is electrically connected to the first tab 11 through at least one first welding portion W1. At least a portion of the sealing plate 33 is accommodated in the recess 31.

[0164] The recess 31 can be recessed from the side of the terminal body 34 away from the electrode assembly 10 along the direction facing the electrode assembly 10. The connecting portion 32 is the part of the terminal body 34 corresponding to the bottom surface of the recess 31.

[0165] The sealing plate 33 can be fully accommodated in the recess 31 or partially accommodated in the recess 31, as long as the sealing plate 33 can seal the first through hole 323.

[0166] The connecting portion 32 is welded to other components to form a first welded portion W1. Exemplarily, the welding equipment can irradiate a laser on the surface of the connecting portion 32 facing the recess 31. The laser melts a part of the connecting portion 32 and a part of the component located inside the connecting portion 32 to form a molten pool. After the molten pool solidifies, the first welded portion W1 is formed.

[0167] In this embodiment, by creating a recess 31 on the terminal body 34, the thickness of the connecting portion 32 can be reduced, thereby reducing the welding power required for welding, lowering the risk of other components being burned, and improving safety. The recess 31 can also provide a receiving space for the sealing plate 33, thereby reducing the size of the sealing plate 33 protruding from the terminal body 34, reducing the space occupied by the electrode terminal 30, and increasing the energy density of the battery cell 7.

[0168] The sealing plate 33 can protect the connection part 32 from the outside, reduce the external impurities entering the recess 31, reduce the risk of the connection part 32 being damaged by external impurities, and improve the sealing performance of the battery cell 7.

[0169] In some embodiments, the thickness of the connecting portion 32 is 0.5mm-10mm.

[0170] In some embodiments, a gap is provided between the sealing plate 33 and the connecting portion 32, the gap being used to avoid the first welding portion W1.

[0171] The surface of the first welded part W1 is uneven. If the sealing plate 33 presses against the first welded part W1, it will cause the sealing plate 33 to wobble during assembly, affecting the sealing effect. In this embodiment, a gap is provided between the sealing plate 33 and the connecting part 32 to avoid direct contact between the sealing plate 33 and the first welded part W1, thereby reducing the wobble of the sealing plate 33 during assembly and improving the sealing effect.

[0172] In some embodiments, a stepped surface 311 is provided on the sidewall of the recess 31, at least a portion of the sealing plate 33 is accommodated in the recess 31, and the stepped surface 311 is used to support the sealing plate 33.

[0173] The recess 31 is a stepped recess that is larger on the outside and smaller on the inside.

[0174] When assembling the sealing plate 33, the stepped surface 311 can support the sealing plate 33 and position it, thereby simplifying the assembly process and forming a gap between the sealing plate 33 and the connecting part 32.

[0175] In some embodiments, the sealing plate 33 is welded to the sidewall of the recess 31 to seal the opening of the recess 31 and the first through hole 323.

[0176] In some embodiments, the connecting portion 32 is provided with a groove 324 recessed from the first outer surface 322 of the connecting portion 32 in the direction facing the electrode assembly 10.

[0177] The connecting portion 32 has a first outer surface 322 and a first inner surface 321 disposed opposite to each other along its own thickness direction. The first inner surface 321 faces the electrode assembly 10, and the first outer surface 322 faces away from the electrode assembly 10. Optionally, both the first outer surface 322 and the first inner surface 321 are planar. The groove 324 is recessed relative to the first outer surface 322 in the direction facing the electrode assembly 10.

[0178] The portion between the bottom wall of the groove 324 and the first inner surface 321 is used for welding with other components to form the first welded portion W1.

[0179] In this embodiment, a groove 324 is formed in the connecting portion 32 to create a stepped structure. A gap is formed between the first outer surface 322 and the bottom wall of the groove 324.

[0180] During the production of the battery cell 7, external equipment needs to cooperate with the connecting part 32. The surface of the first welding part W1 is uneven, and if the external equipment is pressed onto the first welding part W1, the external equipment is easily damaged by the first welding part W1. In this embodiment, a groove 324 is provided to form a gap between the first outer surface 322 and the bottom wall of the groove 324. In this way, the first outer surface 322 can be used to support the external equipment, thereby separating the external equipment from the first welding part W1 and reducing the risk of the external equipment being damaged.

[0181] For example, the external device may be a liquid injection device, a vacuuming device, a welding device, or other device used for the battery cell 7.

[0182] For example, during electrolyte injection, the injection head presses against the first outer surface 322. The first outer surface 322 can support the injection head and cooperate with the injection head to achieve a seal, reducing the risk of electrolyte leakage to the outside of the battery cell 7.

[0183] In some embodiments, the terminal body 34 has a second outer surface 344 and a second inner surface 345 disposed opposite to each other. The second inner surface 345 faces the electrode assembly 10, and the second outer surface 344 faces away from the electrode assembly 10. The recess 31 is recessed from the second outer surface 344 in the direction facing the electrode assembly 10 to the first outer surface 322 of the connecting portion 32.

[0184] In some embodiments, the sealing plate 33 may be welded to the busbar of the battery. In the battery, the busbar may connect the sealing plate 33 of one battery cell 7 and the cover 22 of another battery cell 7 to connect the two battery cells 7 in series.

[0185] In some embodiments, at least a portion of the sealing plate 33 protrudes from the second outer surface 344 of the terminal body 34.

[0186] When it is necessary to weld the busbar component and the sealing plate 33, first attach the busbar component to the upper surface of the sealing plate 33 (i.e., the outer surface of the sealing plate 33 opposite to the connecting part 32), and then weld the busbar component and the sealing plate 33.

[0187] At least a portion of the sealing plate 33 protrudes from the second outer surface 344 to avoid the second outer surface 344 interfering with the fit between the sealing plate 33 and the busbar component, so that the busbar component and the sealing plate 33 fit tightly together.

[0188] In some embodiments, the connecting portion 32 is disposed at one end of the terminal body 34 facing the electrode assembly 10, and the first inner surface 321 and the second inner surface 345 of the connecting portion 32 are flush.

[0189] The second inner surface 345 is the surface of the terminal body 34 facing the electrode assembly 10. The first inner surface 321 of the connecting portion 32 forms a part of the second inner surface 345. In this way, the terminal body 34 can mate with a current collector having a flat plate structure. In this embodiment, the connecting portion 32 can be attached to the current collector simply by attaching the current collector to the second inner surface 345, so as to facilitate the welding of the connecting portion 32 and the current collector.

[0190] In some embodiments, the terminal body 34 includes a columnar portion 341, a first limiting portion 342, and a second limiting portion 343. At least a portion of the columnar portion 341 is located inside the electrode lead-out hole 221. A recess 31 is provided in the columnar portion 341. The first limiting portion 342 and the second limiting portion 343 are both connected to and protrude from the outer side wall of the columnar portion 341. The first limiting portion 342 and the second limiting portion 343 are respectively provided on the outer side and the inner side of the cover 22 and are used to clamp a portion of the cover 22.

[0191] The first limiting part 342 is located on the outer side of the cover 22, meaning that the first limiting part 342 is located on the side of the cover 22 away from the electrode assembly 10; the second limiting part 343 is located on the inner side of the cover 22, meaning that the second limiting part 343 is located on the side of the cover 22 facing the electrode assembly 10.

[0192] In the thickness direction of the cover 22, at least a portion of the first limiting portion 342 overlaps with the cover 22, and at least a portion of the second limiting portion 343 overlaps with the cover 22. A columnar portion 341 passes through the electrode lead-out hole 221 to connect the first limiting portion 342 and the second limiting portion 343 located on both sides of the cover 22.

[0193] The first limiting part 342 and the second limiting part 343 clamp a portion of the cover 22 from both sides to fix the terminal body 34 to the cover 22. The first limiting part 342 and the second limiting part 343 can clamp the cover 22 directly or indirectly through other components.

[0194] Optionally, the columnar portion 341 is cylindrical. The first limiting portion 342 and the second limiting portion 343 are both annular structures surrounding the columnar portion 341.

[0195] In some embodiments, the battery cell 7 further includes a first insulating member 60 and a second insulating member 70. At least a portion of the first insulating member 60 is disposed between the first limiting portion 342 and the cover 22, and at least a portion of the second insulating member 70 is disposed between the second limiting portion 343 and the cover 22. The first insulating member 60 and the second insulating member 70 are used to insulate and isolate the terminal body 34 from the cover 22.

[0196] Both the first insulating member 60 and the second insulating member 70 are annular structures arranged around the columnar portion 341.

[0197] The first insulating member 60 can insulate and isolate the first limiting part 342 from the cover 22, and the second insulating member 70 can insulate and isolate the second limiting part 343 from the cover 22.

[0198] In some embodiments, one of the first insulating member 60 and the second insulating member 70 separates the columnar portion 341 and the cover 22. For example, a portion of the first insulating member 60 extends into the electrode lead-out hole 221 to separate the hole wall of the electrode lead-out hole 221 from the columnar portion 341.

[0199] In some embodiments, the first insulating member 60 and the second insulating member 70 are integrally formed. Alternatively, in other embodiments, the first insulating member 60 and the second insulating member 70 are provided separately and abut against each other.

[0200] In some embodiments, one of the first insulating member 60 and the second insulating member 70 is used to seal the electrode lead-out hole 221. In some examples, the first limiting portion 342 and the cover 22 press against the first insulating member 60, compressing the first insulating member 60 and sealing the electrode lead-out hole 221 from the outside. In other examples, the second limiting portion 343 and the cover 22 press against the second insulating member 70, compressing the second insulating member 70 and sealing the electrode lead-out hole 221 from the inside.

[0201] In some embodiments, the battery cell 7 further includes a sealing ring 80, which is fitted onto the columnar portion 341 and used to seal the electrode lead-out hole 221. Optionally, a portion of the sealing ring 80 extends into the electrode lead-out hole 221 to separate the hole wall of the electrode lead-out hole 221 from the columnar portion 341.

[0202] In some embodiments, the outer periphery of the first limiting portion 342 is provided with a plurality of protrusions 342a, and the plurality of protrusions 342a are arranged at intervals along the circumferential direction of the columnar portion 341.

[0203] Optionally, the multiple protrusions 342a can be arranged at equal intervals along the circumference of the columnar portion 341.

[0204] The first limiting part 342 is a flange structure formed by folding the end of the terminal body 34 away from the electrode assembly 10 outward.

[0205] Before the terminal body 34 is assembled to the housing 20, the first limiting portion 342 of the terminal body 34 is generally cylindrical and located at the upper end of the columnar portion 341, with the outer side wall of the first limiting portion 342 flush with the outer side wall of the columnar portion 341. When assembling the terminal body 34 and the housing 20, the first limiting portion 342 is passed through the electrode lead-out hole 221, and then the first limiting portion 342 is folded outward by pressing it, and the terminal body 34 is riveted to the cover 22.

[0206] Before the first limiting portion 342 is folded over, a plurality of spaced-apart groove structures 342b are formed on the upper end of the first limiting portion 342; after the first limiting portion 342 is folded over, a plurality of spaced-apart protrusion structures 342a are formed along the circumference of the columnar portion 341, and the groove structures 342b are between adjacent protrusion structures 342a. In this embodiment, by providing groove structures 342b and protrusion structures 342a, the difficulty of folding the first limiting portion 342 is reduced, and the stress concentration on the first limiting portion 342 is reduced.

[0207] In some embodiments, the second limiting portion 343 is a limiting structure formed by pressing the end of the terminal body 34 facing the electrode assembly 10 to extend the end of the terminal body 34 facing the electrode assembly 10 outward. When assembling the cover 22 and the terminal body 34, an external device can press the end of the terminal body 34 facing the electrode assembly 10, and the end of the terminal body 34 facing the electrode assembly 10 extends outward under pressure to form the protruding second limiting portion 343.

[0208] In some embodiments, the battery cell 7 further includes a current collector 40 for electrically connecting the electrode terminal 30 and the first tab 11.

[0209] The current collector 40 electrically connects the first tab 11 to the electrode terminal 30. The embodiments of this application do not limit the connection method between the first tab 11 and the current collector 40. For example, the current collector 40 can be connected to the first tab 11 by welding, abutting or bonding.

[0210] The current collector 40 and the electrode terminal 30 are welded together to form at least one first welded part W1.

[0211] For example, the current collector 40 and the connecting portion 32 are welded to form at least one first welded portion W1. When welding the connecting portion 32 and the current collector 40, the first through hole 323 can relieve welding stress and reduce the risk of the connecting portion 32 breaking.

[0212] In some embodiments, in the thickness direction of the connecting portion 32, the first weld portion W1 extends from the side of the connecting portion 32 away from the current collecting member 40 to at least the interior of the current collecting member 40.

[0213] During welding, exemplarily, after the electrode assembly 10 and the current collector 40 are installed into the housing 20 and the current collector 40 is pressed against the connecting portion 32, an external welding device can weld the connecting portion 32 and the current collector 40 from the side of the connecting portion 32 away from the current collector 40 to form a first weld portion W1. The first weld portion W1 is exposed on the surface of the connecting portion 32 away from the current collector 40.

[0214] The first welded portion W1 may penetrate the current collecting member 40. For example, the first welded portion W1 may penetrate the current collecting member 40 and the connecting portion 32, and the first welded portion W1 may be exposed on the surface of the current collecting member 40 away from the connecting portion 32. Of course, the first welded portion W1 may also not penetrate the current collecting member 40, that is, the first welded portion W1 may not be exposed on the surface of the current collecting member 40 away from the connecting portion 32.

[0215] The first welding part W1 extends from the connecting part 32 into the interior of the current collector 40 to connect the current collector 40 and the connecting part 32, thereby reducing the contact resistance between the current collector 40 and the electrode terminal 30 and improving the current carrying capacity.

[0216] In some embodiments, in the thickness direction of the connecting portion 32, the first weld portion W1 does not extend beyond the surface of the current collecting member 40 away from the connecting portion 32.

[0217] The first welded part W1 is spaced at a predetermined distance from the surface of the current collector 40 away from the connecting part 32, so as to avoid the current collector 40 being melted through, reduce the risk of metal particles being generated on the surface of the current collector 40 away from the connecting part 32, and improve safety.

[0218] In some embodiments, the current collector 40 is welded to the first electrode tab 11 to form a second welded portion W2.

[0219] When assembling the battery cell 7, the first tab 11 of the electrode assembly 10 can be welded to the current collector 40 first, and then the electrode assembly 10 and the current collector 40 can be placed into the housing 20. Specifically, when welding the first tab 11 and the current collector 40, the current collector 40 can be pressed against the flattened end face of the first tab 11 first, and then an external welding device emits a laser on the surface of the current collector 40 away from the first tab 11, and the laser welds the current collector 40 and the first tab 11 together.

[0220] The shape of the second welding part W2 can be straight, C-shaped, ring-shaped, spiral, V-shaped, or other shapes, and this embodiment does not limit this. There can be one or more second welding parts W2.

[0221] The second welded part W2 can reduce the contact resistance between the current collector 40 and the first electrode 11, thereby improving the current carrying capacity.

[0222] In some embodiments, the current collector 40 has a protrusion 41 on the side facing the first electrode 11, and the protrusion 41 is welded to the first electrode 11 to form a second welded portion W2.

[0223] When assembling the current collector 40 and the electrode assembly 10, the protrusion 41 of the current collector 40 is first pressed against the first electrode tab 11, and then the protrusion 41 and the first electrode tab 11 are welded together. The protrusion 41 can fit better with the first electrode tab 11, reducing the risk of poor welding.

[0224] In some embodiments, the protrusion 41 can press the first electrode tab 11 and embed it into the first electrode tab 11.

[0225] In some embodiments, apart from the protrusion 41, the other parts of the current collecting member 40 are generally flat plate structures.

[0226] In some embodiments, the current collector 40 forms a recessed structure 44 at a position corresponding to the protrusion 41. The recessed structure 44 is recessed relative to the surface of the current collector 40 facing away from the first electrode tab 11 in a direction facing the first electrode tab 11. A transition portion is formed between the bottom surface of the recessed structure 44 and the top surface of the protrusion 41, and the transition portion is welded to the first electrode tab 11 to form a second weld portion W2. By providing the recessed structure 44, the thickness of the transition portion can be reduced, thereby reducing the welding power required to weld the transition portion to the first electrode tab 11, reducing heat generation, and lowering the risk of the electrode assembly 10 being burned.

[0227] The second welded part W2 is formed by welding, and its surface is uneven. In this embodiment, by providing a recessed structure 44, the surface of the second welded part W2 can be recessed relative to the current collector 40 and away from the surface of the first electrode tab 11, so as to avoid the second welded part W2 from other components (such as electrode terminals 30).

[0228] In some embodiments, the number of first weld portions W1 is one, and the first weld portion W1 extends along the circumferential Y direction of the first through hole 323 and surrounds at least a portion of the first through hole 323.

[0229] The first welded portion W1 can be a ring structure or a semi-ring structure. The dimension of the first welded portion W1 extending in the circumferential direction Y can be determined according to the current carrying capacity requirements of the battery cell 7, and this embodiment does not impose any special restrictions on this.

[0230] The first welded part W1 can increase the strength of the area of ​​the electrode terminal 30 located around the first through hole 323 and reduce the deformation of the electrode terminal 30 under the impact of the electrolyte.

[0231] In some embodiments, the first welded portion W1 surrounds only a portion of the first through hole 323 along the circumferential Y direction of the first through hole 323.

[0232] A portion of the first through hole 323 is surrounded by the first welded portion W1 along the circumferential direction Y of the first through hole 323, and another portion of the first through hole 323 is surrounded by the first welded portion W1 along the circumferential direction Y of the first through hole 323.

[0233] The outer periphery of the first through hole 323 is not closed by the first welding part W1, so the gap between the electrode terminal 30 and the component welded to the electrode terminal 30 (such as the current collector 40) will not be blocked by the first welding part W1. Part of the electrolyte flowing in through the first through hole 323 can pass through the gap, thereby improving the efficiency of electrolyte injection.

[0234] In some embodiments, the angle at which the first welded portion W1 surrounds the first through hole 323 is α, where 180°≤α≤360°.

[0235] Alternatively, α can be 180°, 225°, 270°, 315° or 360°.

[0236] α is positively correlated with the current-carrying area of ​​the first welded portion W1. The smaller α is, the smaller the current-carrying area of ​​the first welded portion W1, and the higher the heat generated when current flows through the first welded portion W1. In the embodiments of this application, α is made to satisfy: 180°≤α≤360°, so that the first welded portion W1 meets the requirements of the battery cell 7 for current carrying capacity and temperature rise.

[0237] Figure 11 This is a schematic diagram of the terminal body of the electrode terminal of a battery cell provided in some other embodiments of this application.

[0238] like Figure 11 As shown, in some embodiments, the first welded portion W1 surrounds the first through hole 323, i.e., α is 360°.

[0239] The embodiments of this application can increase the flow area of ​​the first welded part W1, so that the first welded part W1 meets the requirements of the battery cell 7 for flow capacity and temperature rise, and improve the strength of the first welded part W1, reducing the risk of the first welded part W1 tearing when the battery cell 7 vibrates.

[0240] Figure 12 This is a schematic diagram of the terminal body of the electrode terminal of a battery cell provided in some embodiments of this application.

[0241] Please refer to the above as well. Figures 6 to 9 , Figure 12 In some embodiments, there are multiple first welding portions W1, and the multiple first welding portions W1 are arranged at circumferential Y intervals along the first through hole 323.

[0242] The first welded portion W1 can extend circumferentially along the first through hole 323, or it can extend radially along the first through hole 323.

[0243] In this embodiment, there is no particular limitation on the angle between two adjacent first welded parts W1 in the circumferential Y direction of the first through hole 323. Multiple first welded parts W1 can be arranged at equal intervals or at unequal intervals along the circumferential Y direction of the first through hole 323.

[0244] Given a fixed total area, setting multiple first welding parts W1 can reduce the power of a single welding operation and decrease heat generation compared to setting only one first welding part W1.

[0245] In some embodiments, the interval angle β between any two adjacent first welded portions W1 along the circumferential Y direction of the first through hole 323 is less than 30°.

[0246] The larger the value of angle β, the sparser the distribution of the multiple first welded parts W1, and the smaller the total flow area of ​​the multiple first welded parts W1; the smaller the value of angle β, the denser the distribution of the multiple first welded parts W1, and the larger the total flow area of ​​the multiple first welded parts W1. In this embodiment, β is limited to less than 30° to meet the requirements of the battery cell 7 for flow capacity and temperature rise, and to reduce the risk of the first welded parts W1 tearing when the battery cell 7 vibrates.

[0247] In some embodiments, each first weld portion W1 extends radially along the first through hole 323.

[0248] The radial extension of the first welded part W1 along the first through hole 323 means that the radial dimension of the first welded part W1 along the first through hole 323 is greater than the circumferential dimension Y of the first welded part W1 along the first through hole 323.

[0249] The first welding portion W1 extends radially along the first through hole 323, which can reduce the circumferential Y dimension of the first welding portion W1 along the first through hole 323, so that the electrode terminal 30 can arrange more first welding portions W1 on the outer periphery of the first through hole 323, thereby improving the current carrying capacity and reducing heat generation.

[0250] In some embodiments, the depth of the first welded portion W1 in the axial direction X of the first through hole 323 is h; the minimum distance between the first welded portion W1 and the first through hole 323 in the radial direction is d. d and h satisfy: 0.1≤h / d≤0.6.

[0251] Due to process errors, different areas of the first welded part W1 may have different weld depths along the axial direction X of the first through hole 323. h can be the dimension of the area with the smallest weld depth of the first welded part W1 along the axial direction X of the first through hole 323.

[0252] A larger h value results in higher welding power, higher heat generation during welding, greater thermal stress in the area near the first through-hole 323, and greater deformation of the first through-hole 323. Conversely, a smaller d value results in more heat being conducted to the area near the first through-hole 323 during welding, greater thermal stress in this area, and greater deformation of the first through-hole 323. If h / d is too large, it will cause severe deformation of the first through-hole 323, making it difficult for the injection head to fit properly and affecting injection efficiency. After in-depth research and extensive experiments, the inventors discovered that limiting the value of h / d to less than or equal to 0.6 can reduce the thermal stress in the area near the first through-hole 323, reduce the deformation of the first through-hole 323, and facilitate the fit between the injection head and the first through-hole 323.

[0253] The smaller the value of h, the lower the current-carrying capacity and strength of the first welded part W1, and the higher the risk of tearing of the first welded part W1 when the battery cell 7 vibrates. The larger the value of d, the smaller the area of ​​the electrode terminal 30 that can be used for welding, and the more limited the current-carrying capacity and strength of the first welded part W1. If h / d is too small, the current-carrying capacity and strength of the first welded part W1 will be insufficient. After in-depth research and a large number of experiments, the inventors found that limiting the value of h / d to greater than or equal to 0.1 is necessary to ensure that the current-carrying capacity and strength of the first welded part W1 meet the requirements.

[0254] Optionally, the value of h / d can be 0.1, 0.2, 0.3, 0.4, 0.5 or 0.6.

[0255] In some embodiments, d and h satisfy: 0.2≤h / d≤0.5. After in-depth research and a large number of experiments, the inventors found that when 0.2≤h / d≤0.5, the deformation of the first through hole 323 can be effectively reduced, so that the flow capacity and strength of the first welded part W1 meet the requirements.

[0256] In some embodiments, 1.6mm ≤ d ≤ 5.5mm.

[0257] If d is too small, too much heat will be conducted to the area near the first through hole 323 during the welding process, resulting in excessive thermal stress in the area near the first through hole 323. This will cause severe deformation of the first through hole 323, making it difficult for the injection head to fit into the first through hole 323 and affecting the injection efficiency. If d is too large, the area of ​​the electrode terminal 30 that can be used for welding will be too small, resulting in insufficient current flow capacity and strength of the first welded part W1.

[0258] After in-depth research and a large number of experiments, the inventors discovered that limiting the value of d to 1.6mm-5.5mm can reduce the deformation of the first through hole 323, facilitate the fitting of the injection head with the first through hole 323, and ensure that the flow capacity and strength of the first welded part W1 meet the requirements.

[0259] Optionally, d can be 1.6mm, 2mm, 3mm, 4mm, 5mm or 5.5mm.

[0260] In some embodiments, h is 0.8mm-1.0mm.

[0261] In some embodiments, the electrode assembly 10 is a wound structure, and the electrode assembly 10 has a second through hole 14 at the center of the winding. The first through hole 323 communicates with the second through hole 14 so that the electrolyte injected through the first through hole 323 can flow into the second through hole 14.

[0262] For example, the electrode assembly 10 is formed by winding a first electrode, a second electrode, and a spacer onto a winding tool. After winding, the winding tool is removed from the electrode assembly 10. After the winding tool is removed, a second through hole 14 is formed in the middle of the electrode assembly 10. The second through hole 14 passes through the first tab 11, the main body 12, and the second tab 13.

[0263] Along the axial direction X of the first through hole 323, the first through hole 323 and the second through hole 14 may or may not overlap.

[0264] In this embodiment, the size relationship between the diameter of the first through hole 323 and the diameter of the second through hole 14 is not particularly limited.

[0265] During the electrolyte injection process, the electrolyte can flow into the second through hole 14 through the first through hole 323. The electrolyte flowing into the second through hole 14 can wet the electrode assembly 10 from the inside, thereby improving the wetting efficiency of the electrode assembly 10.

[0266] In some embodiments, the axial direction X of the first through hole 323 is parallel to the axial direction of the second through hole 14.

[0267] In some embodiments, the projection of the first through hole 323 in the axial direction X at least partially overlaps with the projection of the second through hole 14.

[0268] The first through hole 323 and the second through hole 14 are opposite each other along the axial direction X of the first through hole 323. The electrolyte passing through the first through hole 323 can enter the second through hole 14 without changing its flow direction, thereby improving the wetting efficiency of the electrode assembly 10.

[0269] Optionally, when the first through hole 323 is a variable diameter hole, the projection of the first through hole 323 along its own axial direction X refers to the projection of the opening at the inner end of the first through hole 323 along its own axial direction X. When the second through hole 14 is a variable diameter hole, the projection of the second through hole 14 along the axial direction X of the first through hole 323 refers to the projection of the opening at the end of the second through hole 14 near the first through hole 323 along the axial direction X of the first through hole 323.

[0270] In some embodiments, the projection of the second through hole 14 in the axial direction X of the first through hole 323 is greater than the projection of the first through hole 323.

[0271] The area of ​​the projection of the first through hole 323 along its own axial direction X is S1, and the area of ​​the projection of the second through hole 14 along the axial direction X of the first through hole 323 is S2, where S2 is greater than S1.

[0272] Compared to the first through hole 323, the second through hole 14 has a larger cross-sectional area, which allows the second through hole 14 to hold more electrolyte, thus helping to improve the efficiency of electrolyte wetting the electrode assembly 10 from the inside.

[0273] In some embodiments, in the axial direction X of the first through hole 323, the projection of the first through hole 323 is located within the projection of the second through hole 14.

[0274] This embodiment allows the solid portion of the electrode assembly 10 to avoid the first through hole 323, reducing the direct impact of the electrolyte on the electrode assembly 10 and lowering the risk of deformation of the electrode assembly 10. Exemplarily, this embodiment can reduce the impact on the first tab 11 and the insulating member, thus reducing their deformation.

[0275] In some embodiments, the diameter of the first through hole 323 is D1, and the diameter of the second through hole 14 is D2, wherein D1 and D2 satisfy: 65%≤D1 / D2≤95%.

[0276] For example, D1 refers to the minimum diameter of the first through hole 323, and D2 refers to the minimum diameter of the second through hole 14.

[0277] The larger D1 is, the higher the efficiency of electrolyte injection, the shorter the time to fill the electrolyte, the less electrolyte can wet the electrode assembly 10 during the injection process, and the smaller the total amount of electrolyte injected. The smaller D2 is, the smaller the area of ​​the hole wall of the second through hole 14, and the lower the efficiency of electrolyte wetting from the inside of the electrode assembly 10. If D1 / D2 is too large, it will result in insufficient electrolyte injection, affecting the cycle life of the battery cell 7. After in-depth research and a large number of experiments, the inventors found that limiting the value of D1 / D2 to less than or equal to 95% ensures that the electrolyte injection amount meets the requirements.

[0278] A smaller D1 value results in lower electrolyte injection efficiency and a longer time to fill the electrolyte chamber; a larger D2 value results in higher electrolyte wetting efficiency from the electrode assembly 10. If D1 / D2 is too small, the injection time will be too long, leading to lower product production efficiency. Furthermore, a larger D2 value results in a smaller capacity of the electrode assembly 10, lower internal space utilization of the battery cell 7, and lower energy density of the battery cell 7. After in-depth research and extensive experimentation, the inventors discovered that limiting the D1 / D2 value to greater than or equal to 65% improves injection efficiency and reduces energy density loss in the battery cell 7 caused by the second through-hole 14.

[0279] Optionally, the value of D1 / D2 can be 65%, 75%, 85% or 95%.

[0280] In some embodiments, D2 ≥ D1 + 0.2 mm.

[0281] When assembling the battery cell 7, the electrode assembly 10 may be misaligned due to assembly errors, causing the first through hole 323 to be opposite to the solid part of the electrode assembly 10, which will cause the electrode assembly 10 to be impacted by the electrolyte.

[0282] After in-depth research and a large number of experiments, the inventors discovered that making D2≥D1+0.2mm can provide offset margin for the electrode assembly 10, reduce the risk of the solid part of the electrode assembly 10 being opposite the first through hole 323, reduce the direct impact of the electrolyte on the electrode assembly 10, and reduce the risk of deformation of the electrode assembly 10.

[0283] In some embodiments, the central axis of the first through hole 323 is parallel to the central axis of the second through hole 14. Optionally, the central axis of the first through hole 323 coincides with the central axis of the second through hole 14. Exemplarily, the central axis of the second through hole 14 may serve as the central axis A of the electrode assembly 10.

[0284] In some embodiments, the battery cell 7 further includes a current collector 40 for electrically connecting the electrode terminal 30 and the first tab 11. The current collector 40 includes a third through hole 45, at least a portion of which is disposed between the first through hole 323 and the second through hole 14.

[0285] In this embodiment, the diameter of the third through hole 45 is not particularly limited; its diameter can be greater than, less than or equal to the space of the first through hole 323.

[0286] Along the axial direction X of the first through hole 323, the third through hole 45 is opposite to the first through hole 323, that is, the projection of the third through hole 45 along the axial direction X of the first through hole 323 at least partially overlaps with the projection of the first through hole 323 along the axial direction X of the first through hole 323. Along the axial direction X of the first through hole 323, the third through hole 45 is opposite to the second through hole 14, that is, the projection of the third through hole 45 along the axial direction X of the first through hole 323 at least partially overlaps with the projection of the second through hole 14 along the axial direction X of the first through hole 323.

[0287] By providing a third through hole 45, the current collector 40 avoids the electrolyte flowing in through the first through hole 323, reducing the obstruction of the current collector 40 to the electrolyte during the liquid injection process, allowing the electrolyte to pass smoothly through the third through hole 45 and flow into the second through hole 14, thereby improving the wetting efficiency of the electrode assembly 10.

[0288] In some embodiments, the axial direction of the third through hole 45 is parallel to the axial direction X of the first through hole 323.

[0289] In some embodiments, the diameter of the third through hole 45 is greater than or equal to the diameter of the first through hole 323. The diameter of the third through hole 45 is less than or equal to the diameter of the second through hole 14.

[0290] In some embodiments, the projection of the third through hole 45 in the axial direction X of the first through hole 323 is smaller than the projection of the second through hole 14.

[0291] The area of ​​the third through hole 45 projected along the axial direction X of the first through hole 323 is S3, and S2 is greater than S3. For example, the diameter of the third through hole 45 is smaller than the diameter of the second through hole 14.

[0292] Compared to the third through hole 45, the second through hole 14 has a larger cross-sectional area, which allows the electrolyte passing through the third through hole 45 to flow quickly into the second through hole 14, thus helping to improve the efficiency of electrolyte wetting the electrode assembly 10 from the inside.

[0293] In some embodiments, the projection of the third through hole 45 in the axial direction X of the first through hole 323 is larger than the projection of the first through hole 323. For example, the diameter of the third through hole 45 is larger than the diameter of the first through hole 323.

[0294] Compared to the first through hole 323, the third through hole 45 has a larger cross-sectional area, which reduces the risk of the current collector 40 blocking the first through hole 323, allowing the electrolyte to pass smoothly through the third through hole 45 and enter the second through hole 14, thereby improving the efficiency of the electrolyte wetting the electrode assembly 10 from the inside.

[0295] In some embodiments, the projection of the first through hole 323 is located within the projection of the third through hole 45 along the axial direction X.

[0296] This embodiment can reduce the risk of the current collector 40 blocking the first through hole 323, allowing the electrolyte to flow smoothly into the housing 20, and can also reduce the impact on the current collector 40, reducing the risk of cracking at the connection between the current collector 40 and the electrode terminal 30.

[0297] In some embodiments, the projection of the third through-hole 45 is located within the projection of the second through-hole 14 along the axial direction X of the first through-hole 323. This embodiment can reduce the obstruction of the third through-hole 45 by the solid portion of the electrode assembly 10, allowing the electrolyte to flow smoothly into the second through-hole 14.

[0298] In some embodiments, the first through hole 323, the second through hole 14, and the third through hole 45 are coaxially arranged. Coaxial arrangement means that the central axes of the first through hole 323, the second through hole 14, and the third through hole 45 coincide. Of course, this coincidence in this embodiment does not require absolute coincidence, and errors arising from common engineering understanding are permissible.

[0299] By arranging the three through holes coaxially, the flow of electrolyte can be smoother, reducing the impact of electrolyte on the current collector 40 and the electrode assembly 10.

[0300] In some embodiments, the diameter of the third through hole 45 is smaller than the diameter of the second through hole 14, and the current collecting member 40 protrudes radially inward from the hole wall of the second through hole 14. The current collecting member 40 can shield the first electrode tab 11, reducing the impact of the electrolyte on the first electrode tab 11.

[0301] Figure 13 This is a partial cross-sectional schematic diagram of a battery cell provided for other embodiments of this application.

[0302] like Figure 13 As shown, in some embodiments, the electrode terminal 30 is welded to the first tab 11 to form a first welded portion W1.

[0303] and Figure 6 Compared to the battery cells shown, Figure 13 The battery cell 7 shown can eliminate the current collector component, thereby simplifying the internal structure of the battery cell 7, shortening the conductive path between the electrode terminal 30 and the first tab 11, and improving the energy density of the battery cell 7.

[0304] According to some embodiments of this application, a battery is also provided, comprising a plurality of battery cells of any of the above embodiments.

[0305] Figure 14 This is a partial cross-sectional schematic diagram of a battery cell provided for other embodiments of this application.

[0306] like Figure 14As shown, in some embodiments, the recess of the electrode terminal 30 can be omitted. Exemplarily, the first through hole 323 extends through the terminal body 34, and the terminal body 34 may not be provided. Figure 6 The recess 31 is shown. The sealing plate 33 can directly cover the terminal body 34 and seal the first through hole 323.

[0307] Figure 15 This is a cross-sectional schematic diagram of a battery cell provided for other embodiments of this application.

[0308] like Figure 15 As shown, in some embodiments, the battery cell 7 may be a square battery cell.

[0309] In some embodiments, the housing 20 includes an integrally formed cylindrical body 21 and a cover 22, the cylindrical body 21 being disposed around the outer periphery of the electrode assembly 10. Exemplarily, the cylindrical body 21 may be a square tube.

[0310] The cylinder 21 has an opening at the end opposite to the cover 22, and the cover plate 50 covers the opening of the cylinder 21 to close the opening. Exemplarily, the cover plate 50 is welded to the cylinder 21.

[0311] In some embodiments, the battery cell further includes a first electrode terminal 30 and a second electrode terminal 90 with opposite polarities. The first electrode terminal 30 is used to be electrically connected to a first tab of the electrode assembly 10, and the second electrode terminal 90 is used to be electrically connected to a second tab of the electrode assembly 10.

[0312] In some embodiments, the first electrode terminal 30 and the second electrode terminal 90 are both mounted on the cover 22.

[0313] In a battery, a busbar connects the electrode terminals of multiple battery cells to connect them in series, parallel, or mixed connections. Both the first electrode terminal 30 and the second electrode terminal 90 can be used to connect to the busbar.

[0314] When the battery is subjected to an external impact, the busbar component pulls on the cover 22 through the first electrode terminal 30 and the second electrode terminal 90, thereby subjecting the connection between the cover 22 and the cylindrical body 21 to force. If the cover 22 and the cylindrical body 21 are separate structures, for example, if the cover 22 and the cylindrical body 21 are connected by welding, then the connection between the cover 22 and the cylindrical body 21 may fail under the force. In the embodiments of this application, the cover 22 and the cylindrical body 21 are integrally formed, thereby improving the strength of the connection between the cover 22 and the cylindrical body 21 and reducing the risk of connection failure.

[0315] In some embodiments, the housing 20 is not electrically connected to either the positive or negative electrode of the electrode assembly. In other words, the housing 20 is not charged.

[0316] In some embodiments, the first tab and the second tab of the electrode assembly 10 are located on the same side of the electrode assembly facing the cover 22.

[0317] In some embodiments, the first through hole 323 may be formed at the first electrode terminal 30.

[0318] According to some embodiments of this application, an electrical device is also provided, including the battery of any of the above embodiments, the battery being used to provide electrical energy to the electrical device. The electrical device can be any of the aforementioned devices or systems that utilize a single battery cell.

[0319] Reference Figures 4 to 7 According to some embodiments of this application, a cylindrical battery cell 7 is provided, which includes an electrode assembly 10, a housing 20, electrode terminals 30, a current collector 40, and a cover plate 50.

[0320] The housing 20 includes an integrally formed cylindrical body 21 and a cover 22. The cylindrical body 21 is disposed around the outer periphery of the electrode assembly 10, and the cover 22 is provided with an electrode lead-out hole 221. The cylindrical body 21 has an opening 211 at one end opposite to the cover 22, and the cover plate 50 covers the opening of the cylindrical body 21 to close the opening of the cylindrical body 21.

[0321] The electrode assembly 10 is housed within the housing 20 and includes a main body 12, a first electrode tab 11, and a second electrode tab 13, which protrude from the main body 12. The first electrode tab 11 is located at the end of the electrode assembly 10 facing the electrode terminal 30, and the second electrode tab 13 is located at the end of the electrode assembly 10 away from the electrode terminal 30.

[0322] The electrode terminal 30 includes a sealing plate 33 and a terminal body 34. The terminal body 34 is mounted in the electrode lead-out hole 221 and includes a recess 31 and a connecting portion 32 located on the side of the recess 31 facing the electrode assembly 10. A first through hole 323 passes through the connecting portion 32 and is used to inject electrolyte into the internal space of the housing 20. At least a portion of the sealing plate 33 is accommodated in the recess 31, and the sealing plate 33 is connected to the terminal body 34 and is used to seal the first through hole 323.

[0323] The current collector 40 is welded to the connecting part 32 to form at least one first welding part W1, and welded to the first electrode 11 to form at least one second welding part W2, thereby electrically connecting the connecting part 32 and the first electrode 11.

[0324] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0325] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features. However, these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A battery cell, characterized in that, include: Electrode assembly, including a first electrode tab; A housing for accommodating the electrode assembly; An electrode terminal is disposed on the housing and electrically connected to the first electrode tab. The electrode terminal is provided with a first through hole for injecting electrolyte into the internal space of the housing.

2. The battery cell according to claim 1, characterized in that, The electrode terminal is electrically connected to the first electrode tab through at least one first welding part.

3. The battery cell according to claim 2, characterized in that, The number of the first welded portions is one, and the first welded portion extends circumferentially along the first through hole and surrounds at least a portion of the first through hole.

4. The battery cell according to claim 3, characterized in that, The first welded portion surrounds only a portion of the first through hole along the circumference of the first through hole.

5. The battery cell according to claim 3, characterized in that, The angle α around the first through hole is 180°≤α≤360°.

6. The battery cell according to claim 2, characterized in that, There are multiple first welded parts, and the multiple first welded parts are arranged at intervals along the circumference of the first through hole.

7. The battery cell according to claim 6, characterized in that, The circumferential angle between any two adjacent first welded portions along the first through hole is less than 30°.

8. The battery cell according to claim 6, characterized in that, Each of the first weld portions extends radially along the first through hole.

9. The battery cell according to claim 2, characterized in that, In the axial direction of the first through hole, the depth of the first welded part is h; in the radial direction of the first through hole, the minimum distance between the first welded part and the first through hole is d. d and h satisfy: 0.1≤h / d≤0.

6.

10. The battery cell according to claim 9, characterized in that, d and h satisfy: 0.2≤h / d≤0.

5.

11. The battery cell according to claim 9, characterized in that, 1.6mm≤d≤5.5mm.

12. The battery cell according to any one of claims 1-11, characterized in that, The electrode assembly has a wound structure, and the electrode assembly has a second through hole at the center of the winding; The first through hole is connected to the second through hole so that the electrolyte injected through the first through hole can flow into the second through hole.

13. The battery cell according to claim 12, characterized in that, In the axial direction of the first through hole, the projection of the first through hole at least partially overlaps with the projection of the second through hole.

14. The battery cell according to claim 12, characterized in that, Along the axial direction of the first through hole, the projection of the second through hole is larger than the projection of the first through hole.

15. The battery cell according to claim 13, characterized in that, In the axial direction of the first through hole, the projection of the first through hole lies within the projection of the second through hole.

16. The battery cell according to claim 14, characterized in that, The diameter of the first through hole is D1, and the diameter of the second through hole is D2. D1 and D2 satisfy: 65%≤D1 / D2≤95%.

17. The battery cell according to claim 16, characterized in that, D2≥D1+0.2mm.

18. The battery cell according to claim 12, characterized in that, It also includes a current collector for electrically connecting the electrode terminals and the first tab; The current collection component includes a third through hole, at least a portion of which is disposed between the first through hole and the second through hole.

19. The battery cell according to claim 18, characterized in that, Along the axial direction of the first through hole, the projection of the third through hole is smaller than the projection of the second through hole.

20. The battery cell according to claim 18, characterized in that, Along the axial direction of the first through hole, the projection of the third through hole is greater than the projection of the first through hole.

21. The battery cell according to claim 18, characterized in that, In the axial direction of the first through hole, the projection of the first through hole lies within the projection of the third through hole, and the projection of the third through hole lies within the projection of the second through hole.

22. The battery cell according to claim 18, characterized in that, The first through hole, the second through hole, and the third through hole are coaxially arranged.

23. The battery cell according to any one of claims 1-11, characterized in that, The electrode terminal includes a sealing plate and a terminal body. The terminal body is provided with the first through hole, and the sealing plate is connected to the terminal body and used to seal the first through hole.

24. The battery cell according to claim 23, characterized in that, The terminal body includes a recess and a connecting portion located on the side of the recess facing the electrode assembly. The first through hole passes through the connecting portion, and the connecting portion achieves electrical connection with the first electrode tab through at least one first welding portion. At least a portion of the sealing plate is accommodated in the recess.

25. The battery cell according to any one of claims 1-11, characterized in that, The housing includes a cylindrical body and a cover connected to the cylindrical body. The cylindrical body is arranged around the outer periphery of the electrode assembly, and the cover is provided with an electrode lead-out hole. The electrode terminal is disposed in the electrode lead-out hole.

26. The battery cell according to claim 25, characterized in that, The cover and the cylinder are integrally formed.

27. The battery cell according to claim 25, characterized in that, The electrode assembly further includes a second electrode tab, which has the opposite polarity to the first electrode tab, and is electrically connected to the cover.

28. The battery cell according to claim 27, characterized in that, The first tab is located at the end of the electrode assembly facing the electrode terminal, and the second tab is located at the end of the electrode assembly away from the electrode terminal.

29. The battery cell according to claim 27, characterized in that, The second electrode tab is the negative electrode tab, and the base material of the shell is steel.

30. The battery cell according to claim 25, characterized in that, The cylindrical body has an opening at one end away from the cover, and the battery cell also includes a cover plate for closing the opening.

31. The battery cell according to any one of claims 1-11, characterized in that, The electrode terminals extend into the interior of the housing through the electrode lead-out holes.

32. A battery, characterized in that, It includes multiple battery cells according to any one of claims 1-31.

33. An electrical appliance, characterized in that, Includes the battery according to claim 32, the battery being used to provide electrical energy.

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