Battery cells, batteries and power consuming devices

Abstract

The embodiments of the present application provide a battery cell, a battery, and a power consumption 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 to house the electrode assembly. The electrode terminal is installed in the case and electrically connected to the first tab, and the electrode terminal is provided with a first through-hole for injecting electrolyte into the interior space of the case. By providing the first through-hole in the electrode terminal for injecting electrolyte, deformation of the case 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 strength of the case can be reduced.

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This application claims priority to an application filed on August 23, 2021, entitled "Battery Cell and Manufacturing Method and System Therefor, Battery and Power Consumption Device," with International Application No. PCT / CN2021 / 114156, the entire contents of which are incorporated herein by reference.

[0002] This application relates to the field of battery technology, and more particularly to battery cells, batteries and power consuming devices. [Background technology]

[0003] Battery cells are widely applied in electronic devices, such as mobile phones, notebook computers, battery cars, electric cars, electric airplanes, electric steamships, electric toy cars, electric toy steamships, electric toy airplanes and electric tools, etc. The battery cells may include nickel-cadmium battery cells, nickel-hydride battery cells, lithium-ion battery cells and secondary alkaline zinc-manganese battery cells, etc.

[0004] In the development of battery technology, how to simplify the structure of a battery cell is one of the research directions of battery technology. Summary of the Invention

[0005] The present application provides a battery cell, a battery and a power consuming device, which can simplify the structure of the battery cell.

[0006] According to a first aspect, an embodiment of the present application provides a battery cell, the battery cell including an electrode assembly, a case, and an electrode terminal. The electrode assembly includes a first tab. The case is used to accommodate the electrode assembly. The electrode terminal is installed in the case and electrically connected to the first tab, and the electrode terminal is provided with a first through hole for injecting an electrolyte into an internal space of the case.

[0007] In the above technical solution, by opening a first through hole for injecting electrolyte into the electrode terminal, it is possible to reduce deformation of the case during the electrolyte injection process, simplify the structure of the battery cell, and reduce the impact of the first through hole on the strength of the case.

[0008] In some embodiments, the electrode terminal provides electrical connection to the first tab through at least one first weld.

[0009] In the above technical solution, the first welded portion can reduce the resistance between the electrode terminal and the first tab, and improve the overcurrent capability.

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

[0011] In the above technical solution, the first welded portion can increase the strength of the region located around the first through hole of the electrode terminal, and reduce the deformation of the electrode terminal due to the impact of the electrolyte.

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

[0013] In the above technical proposal, the outer periphery of the first through hole is not sealed by the first welded part, and the gap between the electrode terminal and the member welded to the electrode terminal is not blocked by the first welded part, so that some of the electrolyte flowing in through the first through hole passes through this gap, thereby increasing the efficiency of electrolyte injection.

[0014] In some embodiments, the angle that the first weld surrounds the first through hole is α, where 180°≦α≦360°.

[0015] α has a positive correlation with the overcurrent area of ​​the first weld. The smaller α is, the smaller the overcurrent area of ​​the first weld is, and the higher the heat generated when the 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 overcurrent capacity and temperature rise.

[0016] In some embodiments, the first welds are multiple and the multiple first welds are spaced apart circumferentially around the first through hole.

[0017] Assuming that the total area is constant, compared with the method of installing one first weld, the method of installing multiple first welds can reduce the welding power per welding and reduce heat generation.

[0018] In some embodiments, the spacing angle β between the first through holes of any two adjacent first welds along the circumferential direction is less than 30°.

[0019] The larger the value of the angle β, the more sparsely the distribution of the plurality of first welds is, and the smaller the value of the angle β, the more densely the distribution of the plurality of first welds is, and the larger the total overcurrent area of ​​the plurality of first welds is. The embodiment of the present application limits β to be less than 30° to meet the requirements of the battery cell for overcurrent capability and temperature rise, and reduce the risk of the first welds being torn off when the battery cell is vibrated.

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

[0021] In the above technical solution, the first weld extends along the radial direction of the first through hole, and the size of the first weld along the circumferential direction of the first through hole can be reduced, and the electrode terminal can increase the overcurrent capacity and reduce heat generation by arranging more first welds on the outer periphery of the first through hole.

[0022] In some embodiments, the depth of the first weld in the axial direction of the first through hole is h, and the minimum pitch between the first weld and the first through hole in the radial direction of the first through hole is d, where d and h satisfy 0.1≦h / d≦0.6.

[0023] The larger h is, the greater the power required for welding is, the higher the heat generated during the welding process, the greater the thermal stress acting on the area close to the first through hole, and the greater the degree of deformation of the first through hole. The smaller d is, the greater the amount of heat conducted to the area close to the first through hole during the welding process, the greater the thermal stress acting on the area close to the first through hole, and the greater the degree of deformation of the first through hole. If h / d is too large, the first through hole will be greatly deformed, and the injection head will be difficult to fit into the first through hole, which will affect the injection efficiency. The above technical solution limits the value of h / d to 0.6 or less to reduce the thermal stress acting on the area close to the first through hole, reduce the deformation of the first through hole, and make it easier for the injection head to fit into the first through hole.

[0024] The smaller h is, the lower the overcurrent capacity and strength of the first welded part, and the higher the risk of the first welded part being torn when the battery cell is vibrated. The larger d is, the smaller the area available for welding the electrode terminal is, and the overcurrent capacity and strength of the first welded part are limited. If h / d is too small, the overcurrent capacity and strength of the first welded part are insufficient. In the above technical solution, the value of h / d is limited to 0.1 or more, so that the overcurrent capacity and strength of the first welded part meets the requirements.

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

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

[0027] If d is too small, the amount of heat transferred to the area close to the first through hole during the welding process is too large, the thermal stress acting on the area close to the first through hole is too large, the first through hole is greatly deformed, and the injection head is difficult to fit into the first through hole, which affects the injection efficiency. If d is too large, the area available for welding the electrode terminal is small, and the overcurrent capacity and strength of the first weld are insufficient. The above technical solution limits the value of d to 1.6mm to 5.5mm, thereby reducing the deformation of the first through hole, making it easy for the injection head to fit into the first through hole, and the overcurrent capacity and strength of the first weld meet the requirements.

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

[0029] In the above technical proposal, in the 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 infiltrate the electrode assembly from the inside, thereby improving the infiltration efficiency of the electrode assembly.

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

[0031] In the above technical solution, the first through hole and the second through hole are opposite to each other along the axial direction of the first through hole, and a portion of the electrolyte passing through the first through hole enters the second through hole without changing its flow, thereby improving the infiltration efficiency of the electrode assembly.

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

[0033] In the above technical solution, compared with the first through hole, the second through hole has a relatively larger cross-sectional area, and thus the second through hole can accommodate more electrolyte and contribute to improving the efficiency of the electrolyte infiltrating into the electrode assembly from the inside.

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

[0035] According to the above technical solution, the entity part of the electrode assembly can avoid the first through-hole, so as to reduce the electrolyte directly impacting the electrode assembly, and reduce the risk of deformation of the electrode assembly.

[0036] In some embodiments, the diameter of the first through hole is D 1 and the diameter of the second through hole is D 2 and D 1 and D 2 65%≦D 1 / D 2 Meet ≦95%.

[0037] D 1 The larger the value, the higher the efficiency of injecting the electrolyte, the shorter the time it takes for the electrolyte to be filled, the smaller the amount of electrolyte that can infiltrate the electrode assembly during the injection process, and the smaller the total amount of electrolyte injected. 2 The smaller the area of ​​the wall of the second through hole is, the lower the efficiency of the electrolyte infiltrating from the inside of the electrode assembly. 1 / D 2 If the amount of electrolyte injected is too small, it will affect the cycle life of the battery cell. 1 / D 2 By limiting the value to 95% or less, the injection amount of electrolyte meets the requirement.

[0038] D 1 The smaller the value, the lower the efficiency of electrolyte injection, the longer the time it takes for the electrolyte to fill up, and the ... lower the value, the lower the value, 2The larger the D, the more efficiently the electrolyte will infiltrate from the inside of the electrode assembly. 1 / D 2 If D is too small, the injection time is long and the production efficiency is low. 2 The larger the D, the smaller the capacity of the electrode assembly, the lower the internal space utilization rate of the battery cell, and the lower the energy density of the battery cell. 1 / D 2 By limiting the value to 65% or more, the efficiency of electrolyte injection is increased and the loss of energy density of the battery cell due to the second through hole is reduced.

[0039] In some embodiments, D 2 ≧D 1 +0.2mm.

[0040] When assembling a battery cell, due to an assembly error, the electrode assembly may be misaligned, and the first through hole may face the entity part of the electrode assembly, thus causing the electrode assembly to be struck by the electrolyte. 2 ≧D 1 The setting of +0.2 mm provides a margin of deviation for the electrode assembly, reduces the risk that the entity portion of the electrode assembly faces the first through hole, reduces the electrolyte directly impacting the electrode assembly, and reduces the risk that the electrode assembly is deformed.

[0041] In some embodiments, the battery cell further includes a current collecting component for electrically connecting the electrode terminal and the first tab, the current collecting component including a third through hole, at least a portion of the third through hole being disposed between the first through hole and the second through hole.

[0042] In the above technical solution, by installing the third through hole, the current collecting part can avoid the electrolyte flowing in through the first through hole, and the current collecting part can reduce the electrolyte's resistance to the electrolyte during the injection process, and the electrolyte can smoothly pass through the third through hole and flow into the second through hole, thereby improving the infiltration efficiency of the electrode assembly.

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

[0044] In the above technical solution, the second through hole has a relatively larger cross-sectional area than the third through hole, and thus the electrolyte that passes through the third through hole can quickly flow into the second through hole, which can contribute to improving the efficiency of the electrolyte infiltrating into the electrode assembly from the inside.

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

[0046] In the above technical solution, compared with the first through hole, the third through hole has a relatively larger cross-sectional area, thus reducing the risk of the current collecting part blocking the first through hole, and the electrolyte can smoothly pass through the third through hole and enter the second through hole, thereby improving the efficiency of the electrolyte infiltrating into the electrode assembly from the inside.

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

[0048] The above technical solution can reduce the risk of the current collecting part blocking the first through hole, and not only can the electrolyte flow smoothly into the case, but also reduce the impact received by the current collecting part and reduce the risk of the connection point between the current collecting part and the electrode terminal being torn.

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

[0050] The above technical solution can reduce the shielding of the third through-hole of the entity part of the electrode assembly, and the electrolyte can smoothly flow into the second through-hole.

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

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

[0053] In some embodiments, the electrode terminal includes a seal plate and a terminal body, the terminal body having a first through hole, and the seal plate is 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, a sealing plate is connected to the terminal body to reduce the risk of electrolyte leaking through the first through hole and improve the sealing performance.

[0055] In some embodiments, the terminal body includes a recess and a connection portion located on a side of the recess toward the electrode assembly, the first through hole passes through the connection portion, and the connection portion provides an electrical connection with the first tab by at least one first weld. At least a portion of the seal plate is received in the recess.

[0056] In the above technical solution, the recess is provided in the terminal body to reduce the thickness of the connection part, thereby reducing the welding power required for welding, reducing the risk of burning other components, and improving safety. The recess provides an accommodation space for the seal plate, thereby reducing the protruding size of the seal plate from the terminal body, reducing the space occupied by the electrode terminal, and improving the energy density of the battery cell.

[0057] In some embodiments, the case includes a cylindrical body and a lid body connected to the cylindrical body, the cylindrical body is arranged to surround an outer periphery of the electrode assembly, the lid body is provided with an electrode lead-out hole, and the electrode terminal is installed in the electrode lead-out hole.

[0058] In some embodiments, the lid and the cylinder are integrally molded, and the process of connecting the lid and the cylinder is omitted. When the lid and the cylinder are electrically connected to the positive or negative pole of the electrode assembly, the connection between the lid and the cylinder is an integral structure, so that the resistance of the connection between the lid and the cylinder is relatively small, thereby improving the overcurrent capability. The lid may be used to connect to an external component (e.g., a busbar member). When the battery cell is subjected to an external impact, the external component may pull the lid, and a force may be applied to the connection between the lid and the cylinder. The above technical solution improves the strength of the connection between the lid and the cylinder by installing the lid and the cylinder together, and reduces the risk of the connection between the lid and the cylinder being lost.

[0059] In some embodiments, the electrode assembly further includes a second tab, the second tab being of opposite polarity to the first tab, the second tab being electrically connected to the lid.

[0060] In the above technical solution, one of the cover and the electrode terminal can be the positive output terminal of the battery cell, and the other can be the negative output terminal of the battery cell. The above technical solution places the positive output terminal and the negative output terminal on the same side of the battery cell, thus simplifying the connection process between multiple battery cells.

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

[0062] In the above technical solution, the first tab and the second tab are provided on opposite ends of the electrode assembly, respectively, so that the pitch between the first tab and the second tab can be increased, thereby reducing the risk of the first tab and the second tab being conductive, and improving safety.

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

[0064] In the above technical solution, the case is electrically connected to the negative electrode tab, that is, the case is in a low potential state. The steel case is not easily corroded by the electrolyte in a low potential state.

[0065] In some embodiments, the barrel has an opening at an end remote from the lid, and the battery cell further includes a cover plate for sealing the opening.

[0066] According to a second aspect, an embodiment of the present application provides a battery, the battery including a battery cell according to any one of the embodiments of the first aspect.

[0067] According to a third aspect, an embodiment of the present application provides a power consuming device, the power consuming device including a battery of the second aspect for providing electrical energy. [Brief description of the drawings]

[0068] In order to more clearly explain the technical solutions of the embodiments of the present application, the following briefly introduces the drawings that need to be used in the embodiments of the present application. It is obvious that the drawings described below are only some embodiments of the present application, and those skilled in the art can also obtain other drawings based on the drawings without exerting creative efforts. [Figure 1] 1 is a structural schematic diagram of a vehicle according to some embodiments of the present application. [Diagram 2] FIG. 1 is an exploded schematic diagram of a battery according to some embodiments of the present application. [Diagram 3] FIG. 3 is a structural schematic diagram of the battery module shown in FIG. 2. [Figure 4] FIG. 2 is an exploded schematic diagram of a battery cell according to some embodiments of the present application. [Diagram 5] 1 is a cross-sectional schematic diagram of a battery cell according to some embodiments of the present application. [Figure 6] 6 is a schematic enlarged view of a local portion of the battery cell shown in FIG. 5. [Figure 7] FIG. 7 is an enlarged schematic view of the area in the box B in FIG. [Figure 8] FIG. 2 is a schematic diagram of an electrode terminal of a battery cell according to some embodiments of the present application. [Figure 9] FIG. 8 is an enlarged schematic view of the circled frame C in FIG. [Figure 10] FIG. 2 is a schematic diagram of a terminal body of an electrode terminal of a battery cell according to some embodiments of the present application. [Figure 11] 10 is a schematic diagram of a terminal body of an electrode terminal of a battery cell according to some other embodiments of the present application. [Figure 12] FIG. 13 is a schematic diagram of a terminal body of an electrode terminal of a battery cell according to still other embodiments of the present application. [Figure 13] FIG. 2 is a schematic cross-sectional view of a battery cell according to some further embodiments of the present application. [Figure 14] FIG. 2 is a schematic cross-sectional view of a battery cell according to some further embodiments of the present application. [Figure 15] FIG. 2 is a cross-sectional schematic diagram of a battery cell according to some further embodiments of the present application.

[0069] In the drawings, the drawings are not drawn to scale. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0070] In order to make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the following will clearly describe the technical solutions in the embodiments of the present application in conjunction with the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only some of the embodiments of the present application, and not all of the embodiments. All other embodiments obtained based on the embodiments of the present application without the need for creative efforts by those skilled in the art are all within the scope of protection of the present application.

[0071] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by those skilled in the art in the technical field of this application, and the terms used in the specification of this application are only for describing specific embodiments and are not intended to limit this application, and the terms "comprises" and "has" and any variations thereof in the specification and claims of this application and the above drawings are intended to cover non-exclusive "comprises". The terms "first", "second", etc. in the specification and claims of this application or the above drawings are not intended to describe a specific order or subordinate relationship, but are intended to distinguish different objects.

[0072] An "embodiment" referred to in this application means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearances of this phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are they mutually exclusive separate or alternative embodiments of other embodiments.

[0073] In the description of the present application, it should be explained that unless otherwise clearly defined or limited, the terms "attached", "connected", "connected" and "attached" should be understood in a broad sense, for example, may be a fixed connection, a removable connection, or an integral connection, may be a direct connection, may be an indirect connection through an intermediate medium, or may be communication between the insides of two elements. Those skilled in the art can understand the specific meaning of the above terms in the present application according to the specific situation.

[0074] The term "and / or" in this application merely describes the relationship between related objects and indicates that three relationships may exist, for example, A and / or B can represent three cases: A alone, A and B in combination, and B alone. In addition, the character " / " in this application generally indicates that the related objects before and after are in an "or" relationship.

[0075] In the embodiments of the present application, the same reference numerals represent the same elements, and for the sake of brevity, detailed descriptions of the same elements in different embodiments are omitted. It should be understood that the thickness, length, width, etc. of various elements in the embodiments of the present application shown in the drawings, and the overall thickness, length, width, etc. of the integrated device are merely illustrative, and should not constitute any limitations on the present application.

[0076] The term "plurality" as used herein refers to two or more (including two).

[0077] The term "parallel" in this application includes not only the case of absolute parallelism but also the case of approximately parallelism according to engineering standards, and the term "perpendicular" includes not only the case of absolute perpendicularity but also the case of approximately perpendicularity according to engineering standards.

[0078] In the present application, the battery cells may include lithium ion secondary battery cells, lithium ion primary battery cells, lithium sulfur battery cells, sodium lithium ion battery cells, sodium ion battery cells, magnesium ion battery cells, etc., and the embodiments of the present application are not limited thereto.

[0079] The battery referred to in the embodiments of the present application refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity. For example, the battery referred to in the present application may include a battery module or a battery pack. The battery generally includes a housing for packaging one or more battery cells. The housing can prevent liquid or other foreign matter from affecting the charging or discharging of the battery cells.

[0080] The battery cell includes an electrode assembly and an electrolyte, and the electrode assembly includes a positive electrode plate, a negative electrode plate, and a separator. The battery cell is mainly operated by the movement of metal ions between the positive electrode plate and the negative electrode plate. The positive electrode plate includes a positive electrode collector and a positive electrode active material layer, and the positive electrode active material layer is coated on the surface of the positive electrode collector. The positive electrode collector includes a positive electrode collector and a positive electrode tab, and the positive electrode collector is coated with the positive electrode active material layer, and the positive electrode tab is not coated with the positive electrode active material layer. Taking a lithium ion battery as an example, the material of the positive electrode collector may be aluminum, the positive electrode active material layer includes a positive electrode active material, and the positive electrode active material may be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganate, etc. The negative electrode plate includes a negative electrode collector and a negative electrode active material layer, and the negative electrode active material layer is coated on the surface of the negative electrode collector. The negative electrode collector includes a negative electrode current collector and a negative electrode tab, and the negative electrode current collector is coated with the negative electrode active material layer, and the negative electrode tab is not coated with the negative electrode active material layer. The material of the negative electrode collector may be copper, and the negative electrode active material layer includes a negative electrode active material, which may be carbon or silicon, etc. The material of the separator may be PP (polypropylene) or PE (polyethylene), etc.

[0081] The battery cell further includes a case for accommodating the electrode assembly and electrode terminals installed in the case, the electrode terminals being electrically connected to the electrode assembly and used to realize charging and discharging of the electrode assembly.

[0082] During the battery production process, it is necessary to inject electrolyte into the case. In order to realize the injection of electrolyte, the inventors have attempted to open an injection hole in the case. When injection is required, the injection head of the injection device is pressed against the case, and the injection head injects electrolyte into the case through the injection hole.

[0083] However, the inventor found that providing a liquid injection hole in the case would complicate the case structure, and the liquid injection hole would occupy space in the case and affect the installation of other components on the case. Compared with the electrode terminal, the case is relatively thin and has relatively low strength, and during liquid injection, the case may be deformed due to the extrusion of the liquid injection head, which would cause a risk of defects in the outer shape of the battery cell.

[0084] In view of this, the embodiments of the present application provide a technical solution, which opens a through hole for injecting electrolyte into the electrode terminal, thereby reducing the deformation of the case during the injection process, simplifying the structure of the battery cell, and reducing the impact of the first through hole on the strength of the case.

[0085] The technical solutions described in the embodiments of the present application are applicable to batteries and power consuming devices that use batteries.

[0086] The power consumption device may be a vehicle, a mobile phone, a portable device, a notebook computer, a steamship, a spacecraft, an electric toy and an electric tool, etc. The vehicle may be a fuel oil vehicle, a gas vehicle or a new energy vehicle, the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or a range extender vehicle, etc., the spacecraft includes an airplane, a rocket, a space shuttle and a spaceship, etc., the electric toy includes a stationary or mobile electric toy, such as a game console, an electric car toy, an electric steamship toy and an electric airplane toy, etc., and the electric tool includes a metal cutting electric tool, a polishing electric tool, an assembly electric tool and a railway electric tool, such as an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, a hammer drill, a concrete vibrator and an electric planer, etc. The embodiment of the present application does not particularly limit the above power consumption device.

[0087] In the following embodiment, for convenience of explanation, the power consuming device is a vehicle.

[0088] Fig. 1 is a structural schematic diagram of a vehicle according to some embodiments of the present application. As shown in Fig. 1, a battery 2 is installed inside the vehicle 1, and the battery 2 may be installed at the bottom, head, or rear of the vehicle 1. The battery 2 may be used to power the vehicle 1, for example, the battery 2 may be used as an operating power source for the vehicle 1.

[0089] The vehicle 1 may further include a controller 3 and a motor 4, the controller 3 being used to control the battery 2 to power the motor 4, e.g. for start-up, navigation and operating power consumption needs of the vehicle 1 during driving.

[0090] In some embodiments of the present application, the battery 2 can provide not only the operating power source for the vehicle 1, but also the propulsion power source for the vehicle 1, in place of, or in place of, fuel oil or natural gas.

[0091] 2 is an exploded schematic diagram of a battery according to some embodiments of the present application. As shown in FIG. 2, the battery 2 includes a housing 5 and a battery cell (not shown in FIG. 2), and the battery cell is housed in the housing 5.

[0092] The housing 5 is used to house the battery cells, and the housing 5 may have various structures. In some embodiments, the housing 5 may include a first housing portion 5a and a second housing portion 5b, and the first housing portion 5a and the second housing portion 5b are placed over each other, and the first housing portion 5a together with the second housing portion 5b define a housing space 5c for housing the battery cells. The second housing portion 5b may have a hollow structure with an opening at one end, and the first housing portion 5a has a plate-like structure, and the first housing portion 5a is placed over the opening side of the second housing portion 5b to form the housing 5 having the housing space 5c, and both the first housing portion 5a and the second housing portion 5b may have a hollow structure with an opening at one end, and the opening side of the first housing portion 5a is placed over the opening side of the second housing portion 5b to form the housing 5 having the housing space 5c. Of course, the first housing part 5a and the second housing part 5b may have various shapes, for example, a cylinder, a rectangular parallelepiped, and the like.

[0093] In order to improve the sealing performance after the first housing part 5a and the second housing part 5b are connected, a sealing member, such as a sealant or a seal ring, may be installed between the first housing part 5a and the second housing part 5b.

[0094] If the first housing part 5a is placed on top of the second housing part 5b, the first housing part 5a may be referred to as an upper housing cover, and the second housing part 5b may be referred to as a lower housing.

[0095] The battery 2 may have one or more battery cells. When there are multiple battery cells, the multiple battery cells may be connected in series, in parallel, or in series-parallel, and series-parallel connection means that some of the multiple battery cells are connected in series and some are connected in parallel. The multiple battery cells may be directly connected in series, in parallel, or in series-parallel, and then the entirety of the multiple battery cells may be housed in the housing 5. Of course, the multiple battery cells may first be connected in series, in parallel, or in series-parallel to form a battery module 6, and the multiple battery modules 6 may then be connected in series, in parallel, or in series-parallel to form a whole and housed in the housing 5.

[0096] FIG. 3 is a structural schematic diagram of the battery module shown in FIG.

[0097] 3, there are a plurality of battery cells 7, and the plurality of battery cells 7 are first connected in series, in parallel, or in series-parallel to form a battery module 6. The plurality of battery modules 6 are then connected in series, in parallel, or in series-parallel to form a whole, which is housed in a housing.

[0098] The multiple battery cells 7 in the battery module 6 are electrically connected to each other by the bus bar members 8, so that the multiple battery cells 7 in the battery module 6 can be connected in parallel, in series, or in series-parallel. There may be one or more bus bar members, and each bus bar member 8 is used to electrically connect at least two battery cells.

[0099] FIG. 4 is an exploded schematic view of a battery cell according to some embodiments of the present application, FIG. 5 is a cross-sectional schematic view of a battery cell according to some embodiments of the present application, FIG. 6 is a locally enlarged schematic view of the battery cell shown in FIG. 5, and FIG. 7 is an enlarged schematic view of box B in FIG. 6.

[0100] 4 to 7, a battery cell 7 according to an embodiment of the present application includes an electrode assembly 10, a case 20, and an electrode terminal 30. The electrode assembly 10 includes a first tab 11. The case 20 is used to accommodate the electrode assembly 10. The electrode terminal 30 is installed in the case 20 and electrically connected to the first tab 11, and the electrode terminal 30 is provided with a first through-hole 323 for injecting an electrolyte into the internal space of the case 20.

[0101] The electrode assembly 10 includes a first plate and a second plate having opposite polarities. One of the first plate and the second plate is a positive plate, and the other is a negative plate. Exemplarily, the electrode assembly 10 generates electric energy by oxidation and reduction reactions when ions are absorbed / desorbed in the positive plate and the negative plate. Optionally, the electrode assembly 10 further includes a separator for insulating and isolating the first plate and the second plate.

[0102] In some examples, the first plate, the second plate, and the separator are all strip-shaped structures, and the first plate, the second plate, and the separator are wound together around a central axis A to form a wound structure. The wound structure may be a cylindrical structure, a flat structure, or a structure of other shapes. In other examples, the electrode assembly 10 may be a stacked structure formed by arranging the first plate, the separator, and the second plate in a stacked manner.

[0103] The first tab 11 may be a portion of the first electrode plate that is not coated with an active material layer. The first tab 11 may be a positive electrode tab or a negative electrode tab.

[0104] The case 20 has a hollow structure, and the inside thereof forms a space for accommodating the electrode assembly 10. The case 20 may have various shapes and sizes, for example, a rectangular parallelepiped shape, a cylindrical shape, a hexagonal prism shape, etc. The shape of the case 20 may be determined according to the specific shape of the electrode assembly 10. For example, if the electrode assembly 10 has a cylindrical structure, a cylindrical case may be selected, and if the electrode assembly 10 has a rectangular parallelepiped structure, a rectangular parallelepiped case may be selected. Optionally, both the electrode assembly 10 and the case 20 are cylindrical.

[0105] The case 20 may be made of various materials, such as copper, iron, aluminum, stainless steel, and aluminum alloy, and the embodiment of the present application is not particularly limited thereto.

[0106] The case 20 may be positively charged, negatively charged, or uncharged.

[0107] The electrode terminal 30 may be installed in an insulating manner on the case 20 or may be electrically connected to the case 20, but the embodiments of the present application are not limited thereto, as long as electrical conduction between the positive electrode plate and the negative electrode plate is avoided.

[0108] The electrode terminal 30 can be directly connected to the first tab 11 to realize an electrical connection between the electrode terminal 30 and the first tab 11. Exemplarily, the electrode terminal 30 may be connected to the first tab 11 by adhesion, abutment, locking, welding, or other methods.

[0109] Instead, the electrode terminal 30 may be indirectly connected to the first tab 11 by another conductive part to realize the electrical connection between the electrode terminal 30 and the first tab 11. Exemplarily, the conductive part may be simultaneously connected to the first tab 11 and the electrode terminal 30 to realize the electrical connection between the electrode terminal 30 and the first tab 11.

[0110] The electrode terminal 30 may be an output electrode of the battery cell 7, which can electrically connect the battery cell 7 to an external circuit to realize charging and discharging of the battery cell 7. Optionally, the electrode terminal 30 is connected to a bus bar member and used to realize electrical connection between the battery cells 7.

[0111] The number of first through-holes 323 may be one or more.

[0112] During the molding process of the battery cell 7, the first through-hole 323 can connect the outer space of the case 20 to the inner space of the case 20. When injection is required, the injection head of the injection device is pressed against the electrode terminal 30, and the injection head injects the electrolyte into the case 20 through the first through-hole 323.

[0113] By providing a first through hole 323 for injecting electrolyte into the electrode terminal 30, deformation of the case 20 during the electrolyte injection process can be reduced, the structure of the battery cell 7 can be simplified, and the effect of the first through hole 323 on the strength of the case 20 can be reduced.

[0114] In some embodiments, the first through-holes 323 may be used for other processes, such as a conversion process.

[0115] During the chemical formation process of the battery cell 7, gas is generated inside the case 20, and the first through-hole 323 may be used to release the gas inside the case 20 by communicating with an external negative pressure device.

[0116] In some embodiments, the electrode assembly 10 includes a body portion 12, a first tab 11, and a second tab 13, with the first tab 11 and the second tab 13 protruding from the body portion 12. The first tab 11 is a portion of a first plate that is not covered by an active material layer, and the second tab 13 is a portion of a second plate that is not covered by an active material layer.

[0117] The first tab 11 and the second tab 13 may extend from the same side of the body portion 12 or from opposite sides. Illustratively, the first tab 11 is located at an end of the electrode assembly 10 facing the electrode terminal 30, and the second tab 13 is located at an end of the electrode assembly 10 facing away from the electrode terminal 30.

[0118] In some embodiments, the first tab 11 is wound around the central axis A of the electrode assembly 10 in multiple turns, in other words, the first tab 11 includes multiple turns of the tab layer. After the winding is completed, the first tab 11 is generally cylindrical, and a gap remains between the two adjacent turns of the tab layer. The embodiments of the present application may process the first tab 11 to reduce the gap between the tab layers and facilitate the connection of the first tab 11 to other members. For example, the embodiments of the present application may mill and flatten the first tab 11 so that the end region of the first tab 11 away from the body portion 12 is squeezed and converged, and the mill and flattening process forms a dense end face at the end of the first tab 11 away from the body portion 12, reduces the gap between the tab layers, and facilitates the connection of the first tab 11 to other members. Alternatively, the embodiments of the present application may fill a conductive material between the two adjacent turns of the tab layer to reduce the gap between the tab layers.

[0119] In some embodiments, the second tab 13 is wound in multiple turns around the central axis A of the electrode assembly 10, and the second tab 13 includes a tab layer of multiple turns. Illustratively, the second tab 13 is also subjected to a milling and flattening process to reduce gaps between the tab layers of the second tab 13.

[0120] The electrode assembly 10 has a central axis A which is an imaginary straight line. The first electrode plate, the second electrode plate and the separator may be wound around the central axis A.

[0121] In some embodiments, the case 20 includes a cylindrical body 21 and a cover body 22 connected to the cylindrical body 21, the cylindrical body 21 is arranged to surround the outer periphery of the electrode assembly 10, the cover body 22 is provided with an electrode pull-out hole 221, and the electrode terminal 30 is installed in the electrode pull-out hole 221.

[0122] The cover 22 and the barrel 21 may be an integrally formed structure, i.e., the case 20 is a one-piece molded part. Of course, the cover 22 and the barrel 21 may be two separate parts and connected by welding, crimping, adhesive, etc.

[0123] The electrode lead-out hole 221 penetrates the cover 22 so as to facilitate the electrical energy in the electrode assembly 10 being taken out of the case 20 .

[0124] The central axis A is an imaginary 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 and the axis of the electrode lead-out hole 221 may or may not overlap. In some other embodiments, the central axis A may not pass through the electrode lead-out hole 221.

[0125] The electrode terminal 30 is fitted into the electrode lead-out hole 221 and is used to cover the electrode lead-out hole 221. The electrode terminal 30 may or may not enter the electrode lead-out hole 221. The electrode terminal 30 is fixed to the cover 22. The electrode terminal 30 may be entirely fixed to the outside of the cover 22, or may enter the inside of the case 20 via the electrode lead-out hole 221.

[0126] In some embodiments, the tube 21 is a cylinder and the cover 22 is a circular plate-like structure. In other embodiments, the tube 21 may be a square tube and the cover 22 may be a square plate-like structure.

[0127] In some embodiments, the cover 22 and the cylindrical body 21 are integrally molded, thus eliminating the need to connect the cover 22 and the cylindrical body 21.

[0128] When the cover 22 and the cylinder 21 are electrically connected to the positive or negative electrode of the electrode assembly 10, the connection point between the cover 22 and the cylinder 21 has an integral structure, so that the resistance at the connection point between the cover 22 and the cylinder 21 is relatively small, thereby improving the overcurrent capability. The cover 22 may be used to connect to an external component (e.g., a bus bar member), and when the battery cell is subjected to an external impact, the external component may pull the cover 22, and a force may be applied to the connection point between the cover 22 and the cylinder 21. The above technical solution improves the strength of the connection point between the cover 22 and the cylinder 21 by installing the cover 22 and the cylinder 21 together, and reduces the risk of the connection between the cover 22 and the cylinder 21 failing.

[0129] In some embodiments, case 20 may be formed by a drawing process.

[0130] In some embodiments, the cylindrical body 21 has an opening 211 at an end away from the lid body 22 , and the battery cell 7 further includes a cover plate 50 for sealing the opening 211 .

[0131] The cover plate 50 is placed over the opening of the cylindrical body 21 to seal the opening of the cylindrical body 21. The cover plate 50 may have various structures, for example, the cover plate 50 has a plate-like structure.

[0132] 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.

[0133] In some embodiments, the cover plate 50 is welded to the barrel 21 .

[0134] In some embodiments, the cover 22 is circular, the electrode assembly 10 is cylindrical, and the central axis A overlaps with the axis of the electrode lead hole 221. This embodiment does not require that the central axis A and the axis of the electrode lead hole 221 overlap completely, and there may be a variation between them that is allowed in the process.

[0135] In this embodiment, the electrode extraction hole 221 is opened approximately in the center of the lid body 22, and accordingly, the electrode terminal 30 is also attached to the center of the lid body 22. When assembling a plurality of battery cells 7 into sets, the requirements for positioning accuracy of the electrode terminals 30 can be reduced, and the assembly process can be simplified.

[0136] For example, the axis of the electrode lead-out hole 221 and the axis of the lid 22 overlap each other, and the lid 22 has an annular structure disposed around the axis of the electrode lead-out hole 221 .

[0137] For example, the axis of the electrode terminal 30 and the axis of the electrode lead-out hole 221 are aligned with each other.

[0138] In some other embodiments, the lid 22 may be rectangular, and the electrode assembly 10 may be flat. The electrode extraction hole 221 may be provided near an end of the lid 22 along the longitudinal direction thereof.

[0139] In some embodiments, the axis of the first through hole 323 and the axis of the electrode lead hole 221 overlap with each other.

[0140] In some embodiments, the electrode assembly 10 further includes a second tab 13, which is of opposite polarity to the first tab 11, and the second tab 13 is electrically connected to the lid 22.

[0141] The cover 22 itself serves as one output electrode of the battery cell 7, thereby eliminating one conventional electrode terminal 30 and simplifying the structure of the battery cell 7. When a plurality of battery cells 7 are assembled into a set, the cover 22 may be electrically connected to a bus bar member, which not only increases the overcurrent area but also allows for greater flexibility in the structural design of the bus bar member.

[0142] In some embodiments, the barrel 21 is used to connect the second tab 13 and the lid 22 such that the second tab 13 is electrically connected to the lid 22 .

[0143] The cylindrical body 21 may be directly electrically connected to the second tab 13, or may be electrically connected to the second tab 13 by another component. For example, the second tab 13 is electrically connected to the cylindrical body 21 by a cover plate 50.

[0144] The cover 22 and the electrode terminal 30 have different polarities. In this case, one of the cover 22 and the electrode terminal 30 may be the positive output terminal of the battery cell 7, and the other may be the negative output terminal of the battery cell 7. In this embodiment, the positive output terminal and the negative output terminal are installed on the same side of the battery cell 7, and thus the connection process between multiple battery cells 7 can be simplified.

[0145] The cover 22 may be used to electrically connect to the busbar member. The inventors previously tried to open a first through hole in the cover, but the first through hole reduces the connection area between the cover and the busbar member, and reduces the overcurrent area between the cover and the busbar member, making it difficult to meet the battery cell requirements for overcurrent capacity and temperature rise during rapid charging. Therefore, the inventors opened a first through hole 323 for electrolyte injection in the electrode terminal 30 to increase the connection area between the cover 22 and the busbar member.

[0146] In some embodiments, the first tab 11 is located at an end of the electrode assembly 10 toward the electrode terminal 30 and the second tab 13 is located at an end of the electrode assembly 10 away from the electrode terminal 30 .

[0147] By providing the first tab 11 and the second tab 13 at opposite ends of the electrode assembly 10, respectively, the pitch between the first tab 11 and the second tab 13 can be increased, reducing the risk of electrical conduction between the first tab 11 and the second tab 13 and improving safety.

[0148] In some embodiments, the second tab 13 is a negative tab and the substrate material of the case 20 is steel. The substrate material is the primary component in the material construction of the case 20.

[0149] The case 20 is electrically connected to the negative electrode tab, i.e., the case 20 is in a low potential state. The steel case 20 is not easily corroded by the electrolyte in a low potential state.

[0150] The electrode extraction holes 221 in the embodiment of the present application are made after the case 20 is stretch-molded.

[0151] The inventor once tried to roll-press the open end of the cylinder, fold the open end of the cylinder inward to form a burring structure, and the burring structure presses the cover plate to fix the cover plate. The inventor attached an electrode terminal to the cover plate, and the burring structure and the electrode terminal were used as two output poles of the battery cell. However, the larger the size of the burring structure, the higher the risk of curling and wrinkling after molding. If curling and wrinkling occurs in the burring structure, the surface of the burring structure will be uneven, and if the burring structure is welded to an external busbar member, there will be a problem of welding defects. Therefore, the size of the burring structure is relatively limited, which causes the overcurrent capacity of the battery cell to be insufficient.

[0152] In this embodiment, electrode lead-out holes 221 for attaching electrode terminals 30 are formed in the lid 22 using a hole drilling process, and the positive and negative output electrodes are installed at the ends of the battery cells 7 that are away from the openings of the cylindrical body 21, and the lid 22 is formed during the molding process of the case 20, so that flatness can be ensured even after the electrode lead-out holes 221 are drilled, and the connection strength between the lid 22 and the busbar members is ensured. At the same time, because the flatness of the lid 22 is not restricted by its own size, the lid 22 can have a relatively large size, which improves the overcurrent capability of the battery cells 7.

[0153] In some embodiments, the electrode terminal 30 achieves electrical connection with the first tab 11 by at least one first weld W1.

[0154] The electrode terminal 30 is welded to another member to form a first weld W1. Electric current is conducted between the electrode terminal 30 and the first tab 11 by the first weld W1.

[0155] In some examples, the electrode terminal 30 can be directly welded to the first tab 11 to form the first weld W1. For example, a portion of the electrode terminal 30 and a portion of the first tab 11 melt to form a molten pool, and form the first weld W1 after the molten pool solidifies.

[0156] In some other alternative examples, the electrode terminal 30 is welded to another member (e.g., a current collecting part described later) connected to the first tab 11 to form a first welded part W1. For example, a part of the electrode terminal 30 and a part of the current collecting part melt to form a molten pool, and the first welded part W1 is formed after the molten pool solidifies.

[0157] The embodiment of the present application does not particularly limit the shape, position, depth, and number of the first welded portion W1. For example, the shape of the first welded portion W1 may be linear, circular, spiral, V-shaped, or other shapes. The first welded portion W1 may be one or more.

[0158] The first welded portion W1 can reduce the resistance between the electrode terminal 30 and the first tab 11 and improve the overcurrent capability.

[0159] FIG. 8 is a schematic diagram of an electrode terminal of a battery cell according to some embodiments of the present application, FIG. 9 is an enlarged schematic diagram of the circled frame C in FIG. 7, and FIG. 10 is a schematic diagram of a terminal body of an electrode terminal of a battery cell according to some embodiments of the present application.

[0160] Referring also to Figures 6 to 10, in some embodiments, the electrode terminal 30 includes a seal plate 33 and a terminal body 34, the terminal body 34 is provided with a first through hole 323, and the seal plate 33 is connected to the terminal body 34 and is used to seal the first through hole 323.

[0161] After the process related to the first through hole 323 is completed, the seal plate 33 is connected to the terminal body 34 to reduce the risk of electrolyte leaking through the first through hole 323 and improve the sealing performance.

[0162] In some embodiments, the terminal body 34 includes a recess 31 and a connecting portion 32 located on a 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 realizes an electrical connection with the first tab 11 by at least one first weld W1. At least a portion of the seal plate 33 is received in the recess 31.

[0163] The recess 31 can be recessed along a direction from the side of the terminal body 34 away from the electrode assembly 10 toward the electrode assembly 10. The connection portion 32 is a portion corresponding to the bottom surface of the recess 31 of the terminal body 34.

[0164] The seal plate 33 may be entirely or partially housed within the recess 31 as long as the seal plate 33 can seal the first through-hole 323 .

[0165] The connection portion 32 is welded to another member to form a first weld W1. Exemplarily, the welding device irradiates a laser onto a surface of the connection portion 32 facing the recess 31, and the laser melts a part of the connection portion 32 and a part of the member located inside the connection portion 32 to form a molten pool, and the first weld W1 can be formed after the molten pool is solidified.

[0166] In the embodiment of the present application, by providing the recess 31 in the terminal body 34, the thickness of the connection portion 32 is reduced, thereby reducing the welding power required for welding, reducing the risk of other components being burned, and improving safety. The recess 31 provides an accommodation space for the seal plate 33, thereby reducing the size of the seal plate 33 protruding from the terminal body 34, reducing the space occupied by the electrode terminal 30, and improving the energy density of the battery cell 7.

[0167] The sealing plate 33 protects the connection portion 32 from the outside, reduces external impurities entering the first recess 31, reduces the risk of the connection portion 32 being damaged by external impurities, and improves the sealing performance of the battery cell 7.

[0168] In some embodiments, the thickness of the connection portion 32 is between 0.5 mm and 10 mm.

[0169] In some embodiments, a gap is provided between the seal plate 33 and the connection portion 32 to avoid the first weld W1.

[0170] If the surface of the first welded portion W1 is uneven and the seal plate 33 is pressed against the first welded portion W1, the seal plate 33 will rattle during the assembly process, which will affect the sealing effect. In this embodiment, a gap is provided between the seal plate 33 and the connection portion 32, so that the seal plate 33 can avoid the first welded portion W1 and prevent the seal plate 33 from coming into direct contact with the first welded portion W1, thereby reducing the rattle of the seal plate 33 during the assembly process and ensuring the sealing effect.

[0171] In some embodiments, a step surface 311 is provided on the side wall of the recess 31, at least a portion of the seal plate 33 is received in the recess 31, and the step surface 311 is used to support the seal plate 33.

[0172] The recess 31 is a stepped recess having a larger outer side and a smaller inner side.

[0173] When assembling the seal plate 33 , the step surface 311 can support and position the seal plate 33 , thereby simplifying the assembly process and forming a gap between the seal plate 33 and the connection portion 32 .

[0174] In some embodiments, the seal plate 33 is welded to a sidewall of the recess 31 to seal the opening of the recess 31 and the first through hole 323 .

[0175] In some embodiments, the connecting portion 32 is provided with a recessed groove 324 recessed along a direction from the first outer surface 322 of the connecting portion 32 toward the electrode assembly 10 .

[0176] The connecting portion 32 has a first outer surface 322 and a first inner surface 321 disposed opposite to each other along the thickness direction of the connecting portion 32, the first inner surface 321 facing the electrode assembly 10, and the first outer surface 322 facing away from the electrode assembly 10. Optionally, the first outer surface 322 and the first inner surface 321 are both flat. The groove 324 is recessed in the direction toward the electrode assembly 10 relative to the first outer surface 322.

[0177] The portion between the bottom wall of the groove 324 and the first inner surface 321 is welded to another member and is used to form a first welded part W1.

[0178] In this embodiment, a groove 324 is formed in the connecting portion 32, thereby forming a step structure in the connecting portion 32. A gap is formed between the first outer surface 322 and the bottom wall of the groove 324.

[0179] During the production process of the battery cell 7, an external device needs to be fitted to the connection portion 32. The surface of the first welded portion W1 is uneven, and when the external device is pressed against the first welded portion W1, the external device is easily crushed by the first welded portion 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, and thus the first outer surface 322 can be used to support the external device, so as to separate the external device from the first welded portion W1 and reduce the risk of the external device being crushed.

[0180] For example, the external device may be a liquid injection device, an air extraction device, a welding device, or other device used for the battery cell 7.

[0181] For example, during injection, the injection head is pressed against the first outer surface 322, which supports the injection head and fits into the injection head to achieve a seal, thereby reducing the risk of electrolyte leaking outside the battery cell 7.

[0182] In some embodiments, the terminal body 34 has an opposing second outer surface 344 and a second inner surface 345. The second inner surface 345 faces toward 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 toward the electrode assembly 10 to the first outer surface 322 of the connection portion 32.

[0183] In some embodiments, the seal plate 33 may be used to be welded to a bus bar member of a battery, which may connect the seal plate 33 of one battery cell 7 to the lid 22 of another battery cell 7, connecting the two battery cells 7 in series.

[0184] In some embodiments, at least a portion of the seal plate 33 protrudes from the second outer surface 344 of the terminal body 34 .

[0185] When it is necessary to weld the busbar member and the seal plate 33, first, the busbar member is attached to the upper surface of the seal plate 33 (i.e., the outer surface of the seal plate 33 facing away from the connection portion 32), and then the busbar member and the seal plate 33 are welded together.

[0186] At least a portion of the seal plate 33 protrudes from the second outer surface 344, thereby preventing the second outer surface 344 from interfering with the bonding between the seal plate 33 and the bus bar member, and ensuring that the bus bar member is closely attached to the seal plate 33.

[0187] In some embodiments, the connection portion 32 is provided at the end of the terminal body 34 toward the electrode assembly 10 , and the first inner surface 321 of the connection portion 32 is positioned flush with the second inner surface 345 .

[0188] 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 connection part 32 forms a part of the second inner surface 345. In this manner, the terminal body 34 can be fitted to a current collecting part having a flat plate structure. In this embodiment, simply by bonding the current collecting part to the second inner surface 345, bonding of the connection part 32 and the current collecting part can be realized, and welding of the connection part 32 and the current collecting part can be easily realized.

[0189] In some embodiments, the terminal body 34 includes a columnar portion 341, a first stopper portion 342, and a second stopper portion 343, at least a portion of the columnar portion 341 is located within the electrode extraction hole 221, the recess 31 is provided in the columnar portion 341, the first stopper portion 342 and the second stopper portion 343 are both connected to the outer wall of the columnar portion 341 and protrude from the outer wall of the columnar portion 341, and the first stopper portion 342 and the second stopper portion 343 are provided on the outer side and inner side of the cover body 22, respectively, and are used to clamp a portion of the cover body 22.

[0190] Providing the first stopper portion 342 on the outside of the lid body 22 means that the first stopper portion 342 is provided on the side of the lid body 22 that faces away from the electrode assembly 10, and providing the second stopper portion 343 on the inside of the lid body 22 means that the second stopper portion 343 is provided on the side of the lid body 22 that faces the electrode assembly 10.

[0191] In the thickness direction of the lid body 22, at least a portion of the first stopper portion 342 overlaps with the lid body 22, and at least a portion of the second stopper portion 343 overlaps with the lid body 22. The columnar portion 341 passes through the electrode extraction hole 221 and connects the first stopper portion 342 and the second stopper portion 343 located on both sides of the lid body 22, respectively.

[0192] The first stopper portion 342 and the second stopper portion 343 sandwich a part of the lid body 22 from both sides to fix the terminal body 34 to the lid body 22. The first stopper portion 342 and the second stopper portion 343 may directly sandwich the lid body 22, or may indirectly sandwich the lid body 22 via another component.

[0193] Optionally, the columnar portion 341 is cylindrical. The first stopper portion 342 and the second stopper portion 343 are both ring-shaped structures surrounding the columnar portion 341.

[0194] In some embodiments, the battery cell 7 further includes a first insulating part 60 and a second insulating part 70, where at least a portion of the first insulating part 60 is provided between the first stopper portion 342 and the cover body 22, and at least a portion of the second insulating part 70 is provided between the second stopper portion 343 and the cover body 22. The first insulating part 60 and the second insulating part 70 are used to insulate and separate the terminal body 34 and the cover body 22.

[0195] The first insulating component 60 and the second insulating component 70 each have a ring-shaped structure that is disposed so as to surround the columnar portion 341 .

[0196] The first insulating part 60 can insulate and separate the first stopper portion 342 and the lid body 22 , and the second insulating part 70 can insulate and separate the second stopper portion 343 and the lid body 22 .

[0197] In some embodiments, one of the first insulating part 60 and the second insulating part 70 separates the columnar part 341 from the cover body 22. For example, a part of the first insulating part 60 extends into the electrode drawing hole 221 and separates the hole wall of the electrode drawing hole 221 from the columnar part 341.

[0198] In some embodiments, the first insulating component 60 and the second insulating component 70 are integrally formed structures. Alternatively, in other embodiments, the first insulating component 60 and the second insulating component 70 are provided separately and abut one another.

[0199] In some embodiments, one of the first insulating part 60 and the second insulating part 70 is used to seal the electrode drawing hole 221. In some examples, the first stopper part 342 and the cover body 22 push out the first insulating part 60, and the first insulating part 60 is compressed to seal the electrode drawing hole 221 from the outside. In other examples, the second stopper part 343 and the cover body 22 push out the second insulating part 70, and the second insulating part 70 is compressed to seal the electrode drawing hole 221 from the inside.

[0200] In some embodiments, the battery cell 7 further includes a seal ring 80, which is fitted onto the columnar portion 341 and is used to seal the electrode extraction hole 221. Optionally, a portion of the seal ring 80 extends into the electrode extraction hole 221 and separates the hole wall of the electrode extraction hole 221 from the columnar portion 341.

[0201] In some embodiments, the first stopper portion 342 has a plurality of protruding structures 342a on its outer periphery, the plurality of protruding structures 342a being spaced apart along the circumferential direction of the columnar portion 341.

[0202] Alternatively, the multiple protruding structures 342a may be disposed at intervals along the circumferential direction of the columnar portion 341, for example.

[0203] The first stopper portion 342 has a burring structure formed by folding back the end portion of the terminal body 34 that is separated from the electrode assembly 10 outward.

[0204] Before assembling the terminal body 34 to the case 20, the first stopper portion 342 of the terminal body 34 has a substantially cylindrical structure and is located at the upper end of the columnar portion 341, and the outer wall of the first stopper portion 342 is flush with the outer wall of the columnar portion 341. When assembling the terminal body 34 to the case 20, after the first stopper portion 342 passes through the electrode pull-out hole 221, the first stopper portion 342 is pushed out, whereby the first stopper portion 342 is folded back outward and the terminal body 34 is crimped to the cover 22.

[0205] Before folding back the first stopper portion 342, a plurality of groove structures 342b are provided at intervals on the upper end of the first stopper portion 342, and after folding back the first stopper portion 342, a plurality of protrusion structures 342a are formed at intervals along the circumferential direction of the columnar portion 341, and groove structures 342b are provided between adjacent protrusion structures 342a. In this embodiment, by providing the groove structures 342b and the protrusion structures 342a, the difficulty of folding back the first stopper portion 342 is reduced, and the stress concentration on the first stopper portion 342 is reduced.

[0206] In some embodiments, the second stopper portion 343 is a stopper structure formed by pushing out an end portion of the terminal body 34 facing the electrode assembly 10, so that the end portion of the terminal body 34 facing the electrode assembly 10 extends outward. When assembling the cover 22 and the terminal body 34, an external device can push out the end portion of the terminal body 34 facing the electrode assembly 10, and the end portion of the terminal body 34 facing the electrode assembly 10 extends outward due to the action of pressure, forming the protruding second stopper portion 343.

[0207] In some embodiments, the battery cell 7 further includes a current collecting component 40 for electrically connecting the electrode terminal 30 and the first tab 11 .

[0208] The current collecting part 40 electrically connects the first tab 11 to the electrode terminal 30. The embodiments of the present application do not limit the manner of connection between the first tab 11 and the current collecting part 40, for example, the current collecting part 40 may be connected to the first tab 11 by welding, abutting, adhesive, or the like.

[0209] The current collecting part 40 is welded to the electrode terminal 30 to form at least one first weld W1.

[0210] Exemplarily, the current collecting part 40 is welded to the connection part 32 to form at least one first weld part W1. When the connection part 32 and the current collecting part 40 are welded, the first through hole 323 serves to release welding stress, and can reduce the risk of the connection part 32 bursting.

[0211] In some embodiments, in the thickness direction of the connection portion 32, the first weld W1 extends from the side of the connection portion 32 facing away from the current collecting part 40 to at least the inside of the current collecting part 40.

[0212] During welding, for example, after the electrode assembly 10 and the current collecting part 40 are mounted in the case 20 and the current collecting part 40 is pressed against the connection part 32, an external welding device can weld the connection part 32 and the current collecting part 40 from the side of the connection part 32 that is away from the current collecting part 40 to form a first welded part W1. The first welded part W1 is exposed on the surface of the connection part 32 that is away from the current collecting part 40.

[0213] The first weld W1 can penetrate the current collecting part 40, for example, the first weld W1 penetrates between the current collecting part 40 and the connection part 32, and the first weld W1 is exposed on a surface of the current collecting part 40 that is away from the connection part 32. Of course, the first weld W1 does not have to penetrate the current collecting part 40, that is, the first weld W1 is not exposed on a surface of the current collecting part 40 that is away from the connection part 32.

[0214] The first weld W1 extends from the connection portion 32 to the inside of the current collecting part 40 and connects the current collecting part 40 and the connection portion 32, reducing the contact resistance between the current collecting part 40 and the electrode terminal 30 and improving the overcurrent capability.

[0215] In some embodiments, in the thickness direction of the connection portion 32, the first weld W1 does not protrude beyond the surface of the current collecting part 40 that is away from the connection portion 32.

[0216] A predetermined distance is maintained between the first welded portion W1 and the surface of the current collecting part 40 facing away from the connection portion 32 to prevent the current collecting part 40 from melting, reduce the risk of metal particles being generated on the surface of the current collecting part 40 facing away from the connection portion 32, and improve safety.

[0217] In some embodiments, the current collecting piece 40 is welded to the first tab 11 to form a second weld W2.

[0218] When assembling the battery cell 7, the first tab 11 of the electrode assembly 10 can be first welded to the current collecting part 40, and then the electrode assembly 10 and the current collecting part 40 can be placed in the case 20. Specifically, when welding the first tab 11 and the current collecting part 40, the current collecting part 40 can first be pressed against the end surface of the first tab 11 that has been kneaded and flattened, and then an external welding device can emit a laser onto the surface of the current collecting part 40 that is away from the first tab 11, and the current collecting part 40 and the first tab 11 can be welded together by the laser.

[0219] The shape of the second weld W2 may be a straight line, a C-shape, a ring shape, a spiral shape, a V-shape, or other shapes, and this embodiment is not limited thereto. The second weld W2 may be one or more.

[0220] The second welded portion W2 can reduce the contact resistance between the current collecting part 40 and the first tab 11 and improve the overcurrent capability.

[0221] In some embodiments, the current collecting piece 40 has a protrusion 41 on the side facing the first tab 11, which is welded to the first tab 11 to form a second weld W2.

[0222] When assembling the current collecting part 40 and the electrode assembly 10, first, the protrusion 41 of the current collecting part 40 is pressed onto the first tab 11, and then the protrusion 41 and the first tab 11 are welded together. The protrusion 41 is better attached to the first tab 11, and the risk of welding defects can be reduced.

[0223] In some embodiments, the protrusion 41 can be extruded from and integrated into the first tab 11 .

[0224] In some embodiments, other than the protrusions 41, other portions of the current collecting piece 40 are of generally flat plate construction.

[0225] In some embodiments, a recessed structure 44 is formed at a position corresponding to the protruding portion 41 of the current collecting part 40, and the recessed structure 44 is recessed along a direction toward the first tab 11 with respect to a surface of the current collecting part 40 away from the first tab 11. An adapter part is formed between a bottom surface of the recessed structure 44 and a top surface of the protruding portion 41, and the adapter part is welded to the first tab 11 to form a second welded part W2. By providing the recessed structure 44, the thickness of the adapter part can be reduced, the welding power required for welding the adapter part and the first tab 11 can be reduced, the heat generation can be reduced, and the risk of the electrode assembly 10 being burned can be reduced.

[0226] The second welded portion W2 is formed by welding and has an uneven surface. In this embodiment, the recessed structure 44 is provided to recess the surface of the second welded portion W2 relative to the surface of the current collecting part 40 that is away from the first tab 11, so that the second welded portion W2 can avoid other parts (e.g., the electrode terminal 30).

[0227] In some embodiments, the number of the first welds W1 is one, and the first welds W1 extend along the circumferential direction Y of the first through hole 323 and surround at least a portion of the first through hole 323.

[0228] The first weld W1 may have a ring structure or a semi-ring structure. The size of the first weld W1 extending along the circumferential direction Y may be determined according to the requirement of the battery cell 7 for the overcurrent capability, and this embodiment does not particularly limit it.

[0229] The first welded portion W1 can increase the strength of the region around the first through hole 323 of the electrode terminal 30, and reduce deformation of the electrode terminal 30 due to the impact of the electrolyte.

[0230] In some embodiments, the first weld W1 surrounds only a portion of the first through hole 323 along the circumferential direction Y of the first through hole 323.

[0231] A portion of the first through hole 323 is surrounded by the first weld 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 weld W1 along the circumferential direction Y of the first through hole 323.

[0232] The outer periphery of the first through hole 323 is not sealed by the first welded part W1, and the gap between the electrode terminal 30 and a member (e.g., the current collecting part 40) welded to the electrode terminal 30 is not blocked by the first welded part W1, so that some of the electrolyte flowing in through the first through hole 323 passes through this gap, thereby increasing the efficiency of electrolyte injection.

[0233] In some embodiments, the angle that the first weld W1 surrounds the first through hole 323 is α, where 180°≦α≦360°.

[0234] Alternatively, α may be 180°, 225°, 270°, 315° or 360°.

[0235] α has a positive correlation with the overcurrent area of ​​the first weld W1. The smaller α is, the smaller the overcurrent area of ​​the first weld W1 is, and the higher the heat generated when a current flows through the first weld W1. In the embodiment of the present application, α satisfies 180°≦α≦360°, so that the first weld W1 meets the requirements of the battery cell 7 for overcurrent capacity and temperature rise.

[0236] FIG. 11 is a schematic diagram of a terminal body of an electrode terminal of a battery cell according to some further embodiments of the present application.

[0237] As shown in FIG. 11, in some embodiments, the first weld W1 surrounds the first through hole 323, ie, α is 360°.

[0238] The embodiment of the present application increases the overcurrent area of ​​the first weld W1, allows the first weld W1 to meet the requirements of the battery cell 7 for overcurrent capacity and temperature rise, increases the strength of the first weld W1, and reduces the risk that the first weld W1 will tear when the battery cell 7 vibrates.

[0239] FIG. 12 is a schematic diagram of a terminal body of an electrode terminal of a battery cell according to still another embodiment of the present application.

[0240] Referring to Figures 6 to 9 and Figure 12 together, in some embodiments, the first welds W1 are multiple, and the multiple first welds W1 are spaced apart along the circumferential direction Y of the first through hole 323.

[0241] The first welded portion W1 may extend along the circumferential direction Y of the first through hole 323, or may extend along the radial direction of the first through hole 323.

[0242] In this embodiment, there is no particular limitation on the interval angle between two adjacent first welds W1 in the circumferential direction Y of the first through hole 323. The multiple first welds W1 may be disposed at equal intervals or unequal intervals along the circumferential direction Y of the first through hole 323.

[0243] Assuming that the total area is constant, compared with the method of installing one first weld W1, the method of installing multiple first welds W1 can reduce the welding power per welding and reduce heat generation.

[0244] In some embodiments, the interval angle β between the first through holes 323 of any two adjacent first welds W1 along the circumferential direction Y is less than 30°.

[0245] The larger the value of angle β, the more sparsely the distribution of the multiple first welds W1 and the smaller the total overcurrent area of ​​the multiple first welds W1, and the smaller the value of angle β, the more densely the distribution of the multiple first welds W1 and the larger the total overcurrent area of ​​the multiple first welds W1. The embodiment of the present application limits β to less than 30° to meet the requirements of the battery cell 7 for overcurrent capacity and temperature rise, and reduce the risk of the first welds W1 being torn when the battery cell 7 vibrates.

[0246] In some embodiments, each first weld W1 extends along a radial direction of the first through hole 323.

[0247] The first weld W1 extending along the radial direction of the first through hole 323 means that the size of the first weld W1 along the radial direction of the first through hole 323 is larger than the size of the first weld W1 along the circumferential direction Y of the first through hole 323.

[0248] The first weld W1 extends radially of the first through hole 323, and the size of the first weld W1 along the circumferential direction Y of the first through hole 323 can be reduced. By arranging more of the first weld W1 around the outer periphery of the first through hole 323, the electrode terminal 30 can increase the overcurrent capability and reduce heat generation.

[0249] In some embodiments, the depth of the first weld W1 in the axial direction X of the first through hole 323 is h, and the minimum pitch between the first weld W1 and the first through hole 323 in the radial direction of the first through hole 323 is d, where d and h satisfy 0.1≦h / d≦0.6.

[0250] Due to process tolerances, different regions of the first weld W1 may have different penetrations in the axial direction X of the first through hole 323. h may be the size along the axial direction X of the first through hole 323 of the region of the first weld W1 with the least penetration.

[0251] The larger h is, the greater the power required for welding is, the higher the heat generated during the welding process, the greater the thermal stress acting on the area close to the first through hole 323, and the greater the degree of deformation of the first through hole 323. The smaller d is, the greater the amount of heat conducted to the area close to the first through hole 323 during the welding process, the greater the thermal stress acting on the area close to the first through hole 323, and the greater the degree of deformation of the first through hole 323. If h / d is too large, the first through hole 323 is significantly deformed, and the injection head is difficult to fit into the first through hole 323, which affects the injection efficiency. After intensive research and a large number of experiments, the inventors have found that by limiting the value of h / d to 0.6 or less, the thermal stress acting on the area close to the first through hole 323 can be reduced, the deformation of the first through hole 323 can be reduced, and the injection head can be easily fitted into the first through hole 323.

[0252] The smaller h is, the lower the overcurrent capacity and strength of the first welded portion W1, and the higher the risk of the first welded portion W1 being torn when the battery cell 7 vibrates. The larger d is, the smaller the area available for welding the electrode terminal 30, and the more limited the overcurrent capacity and strength of the first welded portion W1. If h / d is too small, the overcurrent capacity and strength of the first welded portion W1 will be insufficient. After extensive research and a large number of experiments, the inventors have found that by limiting the value of h / d to 0.1 or more, the overcurrent capacity and strength of the first welded portion W1 can meet the requirements.

[0253] Alternatively, the value of h / d may be 0.1, 0.2, 0.3, 0.4, 0.5 or 0.6.

[0254] In some embodiments, d and h satisfy 0.2≦h / d≦0.5. After intensive research and a large number of experiments, the inventors find that when 0.2≦h / d≦0.5, the deformation of the first through hole 323 can be effectively reduced, and the overcurrent capacity and strength of the first weld W1 can meet the requirements.

[0255] In some embodiments, 1.6 mm≦d≦5.5 mm.

[0256] If d is too small, the amount of heat conducted to the area close to the first through hole 323 during the welding process is too large, the thermal stress acting on the area close to the first through hole 323 is too large, the first through hole 323 is significantly deformed, and the injection head is difficult to fit into the first through hole 323, affecting the injection efficiency. If d is too large, the area available for welding the electrode terminal 30 is small, and the overcurrent capacity and strength of the first welded part W1 are insufficient.

[0257] As a result of intensive research and extensive experimentation, the inventors have found that by limiting the value of d to 1.6 mm to 5.5 mm, the deformation of the first through hole 323 can be reduced, the injection head can be easily fitted into the first through hole 323, and the overcurrent capacity and strength of the first welded part W1 can meet the requirements.

[0258] Optionally, d is 1.6 mm, 2 mm, 3 mm, 4 mm, 5 mm or 5.5 mm.

[0259] In some embodiments, h is between 0.8 mm and 1.0 mm.

[0260] In some embodiments, the electrode assembly 10 has 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.

[0261] Exemplarily, the electrode assembly 10 is produced by winding the first electrode plate, the second electrode plate and the separator around a winding tool, and after winding, the winding tool is withdrawn from the electrode assembly 10. After the winding tool is withdrawn, a second through hole 14 is formed in the center of the electrode assembly 10. The second through hole 14 passes through the first tab 11, the body portion 12 and the second tab 13.

[0262] In 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.

[0263] In the embodiment of the present application, the size relationship between the hole diameter of the first through hole 323 and the hole diameter of the second through hole 14 is not particularly limited.

[0264] In the liquid injection process, the electrolyte can flow into the second through hole 14 through the first through hole 323, and the electrolyte flowing into the second through hole 14 can infiltrate the electrode assembly 10 from the inside, thereby improving the infiltration efficiency of the electrode assembly 10.

[0265] 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 .

[0266] In some embodiments, in the axial direction X of the first through hole 323, the projection of the first through hole 323 at least partially overlaps with the projection of the second through hole 14.

[0267] The first through hole 323 and the second through hole 14 face each other along the axial direction X of the first through hole 323, and a portion of the electrolyte passing through the first through hole 323 enters the second through hole 14 without changing its flow, thereby improving the infiltration efficiency of the electrode assembly 10.

[0268] Alternatively, when the first through hole 323 is a diameter-changing hole, the projection of the first through hole 323 along its own axial direction X is a projection of an opening at an inner end of the first through hole 323 along its own axial direction X. When the second through hole 14 is a diameter-changing hole, the projection of the second through hole 14 along the axial direction X of the first through hole 323 is a projection of an opening at an end of the second through hole 14 closer to the first through hole 323 along the axial direction X of the first through hole 323.

[0269] In some embodiments, the projection of the second through hole 14 in the axial direction X of the first through hole 323 is larger than the projection of the first through hole 323 .

[0270] The area of ​​the projection of the first through hole 323 along the axial direction X of the first through hole 323 itself 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, which is greater than S1.

[0271] Compared with the first through hole 323, the second through hole 14 has a relatively larger cross-sectional area, and thus the second through hole 14 can accommodate more electrolyte and contribute to improving the efficiency with which the electrolyte infiltrates the electrode assembly 10 from the inside.

[0272] In some embodiments, in the axial direction X of the first through hole 323, the projection of the first through hole 323 lies within the projection of the second through hole 14.

[0273] According to this embodiment, the entity part of the electrode assembly 10 can avoid the first through-hole 323, reducing the electrolyte directly impacting the electrode assembly 10 and reducing the risk of deformation of the electrode assembly 10. For example, the embodiment of the present application can reduce the impact received by the first tab 11 and the separator and reduce the deformation of the first tab 11 and the separator.

[0274] In some embodiments, the diameter of the first through hole 323 is D 1 and the diameter of the second through hole 14 is D 2 and D 1 and D 2 65%≦D1 / D 2 Meet ≦95%.

[0275] For example, D 1 is the minimum diameter of the first through hole 323, and D 2 is the minimum diameter of the second through hole 14.

[0276] D 1 The larger the value, the higher the efficiency of injecting the electrolyte, the shorter the time it takes for the electrolyte to be filled, the smaller the amount of electrolyte that can permeate the electrode assembly 10 during the injection process, and the smaller the total amount of electrolyte that is injected. 2 The smaller the area of ​​the wall of the second through hole 14 is, the lower the efficiency of the electrolyte infiltrating from the inside of the electrode assembly 10. 1 / D 2 If D is too large, the amount of electrolyte injected is small, which affects the cycle life of the battery cell 7. 1 / D 2 It was found that the amount of electrolyte injected could meet the requirement by limiting the value to 95% or less.

[0277] D 1 The smaller the value, the lower the efficiency of electrolyte injection, the longer the time it takes for the electrolyte to fill up, and the ... lower the value, the lower the value, 2 The larger the D, the more efficiently the electrolyte will infiltrate from the inside of the electrode assembly 10. 1 / D 2 If D is too small, the injection time is long and the production efficiency is low. 2 The larger the D, the smaller the capacity of the electrode assembly 10, the lower the internal space utilization rate of the battery cell 7, and the lower the energy density of the battery cell 7. 1 / D 2 It has been found that by limiting the value of to 65% or more, the efficiency of electrolyte injection is increased and the loss of energy density of the battery cell 7 due to the second through-hole 14 is reduced.

[0278] Optionally, D 1 / D2 The value may be 65%, 75%, 85% or 95%.

[0279] In some embodiments, D 2 ≧D 1 +0.2mm.

[0280] When assembling the battery cell 7, due to an assembly error, the electrode assembly 10 may be misaligned, and the first through hole 323 may face the entity portion of the electrode assembly 10, thus causing the electrode assembly 10 to be impacted by the electrolyte.

[0281] After extensive research and experimentation, the inventors have discovered that 2 ≧D 1 It was found that setting the thickness to +0.2 mm provides the electrode assembly 10 with a margin of error, reduces the risk that the entity portion of the electrode assembly 10 faces the first through hole 323, reduces the amount of electrolyte that directly impacts the electrode assembly 10, and reduces the risk that the electrode assembly 10 is deformed.

[0282] 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 and the central axis of the second through hole 14 overlap. Illustratively, the central axis of the second through hole 14 may be the central axis A of the electrode assembly 10.

[0283] In some embodiments, the battery cell 7 further includes a current collecting part 40 for electrically connecting the electrode terminal 30 and the first tab 11. The current collecting part 40 includes a third through hole 45, and at least a portion of the third through hole 45 is provided between the first through hole 323 and the second through hole 14.

[0284] In this embodiment, the hole diameter of the third through hole 45 is not particularly limited, and the hole diameter may be larger, smaller, or equal to the space of the first through hole 323 .

[0285] In the axial direction X of the first through hole 323, the third through hole 45 faces the first through hole 323, i.e., a projection of the third through hole 45 along the axial direction X of the first through hole 323 at least partially overlaps with a projection of the first through hole 323 along the axial direction X of the first through hole 323. In the axial direction X of the first through hole 323, the third through hole 45 faces the second through hole 14, i.e., a projection of the third through hole 45 along the axial direction X of the first through hole 323 at least partially overlaps with a projection of the first through hole 323 of the second through hole 14 along the axial direction X of the first through hole 323.

[0286] By providing the third through hole 45, the collecting part 40 can avoid the electrolyte flowing in through the first through hole 323, reducing the resistance of the collecting part 40 to the electrolyte during the injection process, and the electrolyte can smoothly flow into the second through hole 14 through the third through hole 45, thereby improving the infiltration efficiency of the electrode assembly 10.

[0287] 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 .

[0288] In some embodiments, the diameter of the third through hole 45 is equal to or larger than the diameter of the first through hole 323. The diameter of the third through hole 45 is equal to or smaller than the diameter of the second through hole 14.

[0289] 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 .

[0290] 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 larger than S3. Exemplarily, the hole diameter of the third through hole 45 is smaller than the hole diameter of the second through hole 14.

[0291] Compared with the third through hole 45, the second through hole 14 has a relatively large cross-sectional area, and thus the electrolyte through the third through hole 45 can quickly flow into the second through hole 14, which can contribute to improving the efficiency with which the electrolyte infiltrates the electrode assembly 10 from the inside.

[0292] In some embodiments, a projection of the third through hole 45 in the axial direction X of the first through hole 323 is larger than a projection of the first through hole 323. Exemplarily, the hole diameter of the third through hole 45 is larger than the hole diameter of the first through hole 323.

[0293] Compared with the first through hole 323, the third through hole 45 has a relatively larger cross-sectional area, thus reducing the risk of the current collecting part 40 blocking the first through hole 323, and the electrolyte can smoothly enter the second through hole 14 through the third through hole 45, thereby improving the efficiency of the electrolyte infiltrating into the electrode assembly 10 from the inside.

[0294] In some embodiments, in the axial direction X of the first through hole 323, the projection of the first through hole 323 lies within the projection of the third through hole 45.

[0295] This embodiment can reduce the risk of the current collecting part 40 blocking the first through hole 323, and not only can the electrolyte flow smoothly into the case 20, but also reduce the impact received by the current collecting part 40 and reduce the risk of the connection point between the current collecting part 40 and the electrode terminal 30 being torn.

[0296] In some embodiments, the projection of the third through hole 45 is located within the projection of the second through hole 14 in the axial direction X of the first through hole 323. This embodiment can reduce the shielding of the entity part of the electrode assembly 10 to the third through hole 45, and the electrolyte can smoothly flow into the second through hole 14.

[0297] In some embodiments, the first through hole 323, the second through hole 14, and the third through hole 45 are arranged coaxially. Arranged coaxially means that the central axis of the first through hole 323, the central axis of the second through hole 14, and the central axis of the third through hole 45 are overlapped. Of course, the overlap in this embodiment does not require absolute overlap, and allows for the existence of an error that is within the scope of common sense in engineering.

[0298] By arranging the three through holes coaxially, the inflow of the electrolyte is smoother, and the impact of the electrolyte on the current collecting member 40 and the electrode assembly 10 can be reduced.

[0299] 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 part 40 protrudes radially inward of the second through hole 14 beyond the wall of the second through hole 14. The current collecting part 40 shields the first tab 11 and can reduce the impact of the electrolyte received by the first tab 11.

[0300] FIG. 13 is a schematic local cross-sectional view of a battery cell according to some further embodiments of the present application.

[0301] As shown in FIG. 13, in some embodiments, the electrode terminal 30 is welded to the first tab 11 to form a first weld W1.

[0302] Compared with the battery cell shown in FIG. 6, the battery cell 7 shown in FIG. 13 omits the current collecting components, 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 increasing the energy density of the battery cell 7.

[0303] According to some embodiments of the present application, there is further provided a battery, the battery including a plurality of the battery cells of any one of the above embodiments.

[0304] FIG. 14 is a schematic local cross-sectional view of a battery cell according to some further embodiments of the present application.

[0305] As shown in Fig. 14, in some embodiments, the recess of the electrode terminal 30 can be omitted. Illustratively, the first through-hole 323 penetrates the terminal body 34, and the terminal body 34 does not need to have the recess 31 shown in Fig. 6. The seal plate 33 may be directly placed on the terminal body 34 to seal the first through-hole 323.

[0306] FIG. 15 is a cross-sectional schematic diagram of a battery cell according to some further embodiments of the present application.

[0307] As shown in FIG. 15, in some embodiments, the battery cells 7 may be rectangular battery cells.

[0308] In some embodiments, the case 20 includes a cylindrical body 21 and a cover body 22 that are integrally formed, and the cylindrical body 21 is disposed so as to surround the outer periphery of the electrode assembly 10. For example, the cylindrical body 21 may be a rectangular cylinder.

[0309] The cylindrical body 21 has an opening at an end remote from the lid body 22, and the cover plate 50 is placed over the opening of the cylindrical body 21 to seal the opening of the cylindrical body 21. For example, the cover plate 50 is welded to the cylindrical body 21.

[0310] In some embodiments, the battery cell further includes a first electrode terminal 30 and a second electrode terminal 90 of opposite polarity, where the first electrode terminal 30 is used to electrically connect to a first tab of the electrode assembly 10 and the second electrode terminal 90 is used to electrically connect to a second tab of the electrode assembly 10.

[0311] In some embodiments, the first electrode terminal 30 and the second electrode terminal 90 are both attached to the lid 22 .

[0312] In a battery, the busbar members are connected to the electrode terminals of multiple battery cells to connect the multiple battery cells in series, parallel, or series-parallel. Both the first electrode terminal 30 and the second electrode terminal 90 may be used to connect to the busbar members.

[0313] When the battery receives an external impact, the bus bar member pulls the lid body 22 by the first electrode terminal 30 and the second electrode terminal 90, and a force acts on the connection point between the lid body 22 and the cylindrical body 21. When the lid body 22 and the cylindrical body 21 are separate structures, for example, when the lid body 22 and the cylindrical body 21 are connected by welding, the connection point between the lid body 22 and the cylindrical body 21 may lose its connection due to the action of the force. In the embodiment of the present application, the lid body 22 and the cylindrical body 21 are integrally installed, thereby improving the strength of the connection point between the lid body 22 and the cylindrical body 21 and reducing the risk of the connection between the lid body 22 and the cylindrical body 21 losing its connection.

[0314] In some embodiments, the case 20 is not electrically connected to the positive terminal of the electrode assembly, nor is it electrically connected to the negative terminal of the electrode assembly, in other words, the case 20 does not become electrically charged.

[0315] 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 toward the lid 22 .

[0316] In some embodiments, the first through-hole 323 may be opened in the first electrode terminal 30 .

[0317] According to some embodiments of the present application, there is further provided a power consuming device, the power consuming device including the battery of any one of the above embodiments, the battery being used to provide electrical energy to the power consuming device. The power consuming device may be any one of the above devices or systems that apply a battery cell.

[0318] 4 to 7, according to some embodiments of the present application, a cylindrical battery cell 7 is provided, which includes an electrode assembly 10, a case 20, an electrode terminal 30, a current collecting part 40, and a cover plate 50.

[0319] The case 20 includes a cylindrical body 21 and a lid body 22 which are integrally formed, the cylindrical body 21 is disposed so as to surround the outer periphery of the electrode assembly 10, and the lid body 22 is provided with an electrode extraction hole 221. The cylindrical body 21 has an opening 211 at an end remote from the lid body 22, and the cover plate 50 is placed over the opening of the cylindrical body 21 to seal the opening of the cylindrical body 21.

[0320] The electrode assembly 10 is housed in a case 20 and 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 located at an end of the electrode assembly 10 facing the electrode terminal 30, and the second tab 13 is located at an end of the electrode assembly 10 away from the electrode terminal 30.

[0321] The electrode terminal 30 includes a seal plate 33 and a terminal body 34, the terminal body 34 is attached to the electrode pull-out hole 221, the terminal body 34 includes a recess 31 and a connection part 32 located on the side of the recess 31 facing the electrode assembly 10, and a first through hole 323 passes through the connection part 32, and the first through hole 323 is used to inject an electrolyte into the internal space of the case 20. At least a portion of the seal plate 33 is accommodated in the recess 31, the seal plate 33 is connected to the terminal body 34, and is used to seal the first through hole 323.

[0322] The current collecting part 40 is welded to the connection part 32 to form at least one first weld W1, and the current collecting part 40 is welded to the first tab 11 to form at least one second weld W2, thereby electrically connecting the connection part 32 and the first tab 11.

[0323] It should be noted that, unless contradictory, the embodiments and features in the embodiments in the present application can be combined with each other.

[0324] Finally, it should be noted that the above examples are only for illustrating the technical solutions of the present application, and are not intended to limit the same. Although the present application has been described in detail with reference to the above examples, those skilled in the art may still modify the technical solutions described in the above examples or make equivalent substitutions for some of the technical features thereof, and such modifications or substitutions shall not deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A battery cell, an electrode assembly including a first tab; a case for housing the electrode assembly; an electrode terminal that is installed in the case, electrically connected to the first tab, and has a first through hole for injecting an electrolyte into an internal space of the case; The electrode assembly has a wound structure, and the electrode assembly has a second through hole at a winding center portion, the first through hole communicates with the second through hole so that an electrolyte injected through the first through hole can flow into the second through hole; A projection of the second through hole in an axial direction of the first through hole is larger than a projection of the first through hole; the electrode terminal is electrically connected to the first tab by at least one first weld; A battery cell, wherein the first welded portion surrounds only a portion of the first through hole along a circumferential direction of the first through hole, or the first welded portion is multiple and the multiple first welded portions are arranged at intervals along a circumferential direction of the first through hole.

2. The battery cell according to claim 1 , wherein the first welded portion surrounds the first through hole at an angle α, where 180°≦α≦360°.

3. The battery cell according to claim 1 , wherein an interval angle between any two adjacent first welds in the circumferential direction of the first through holes is smaller than 30°.

4. The battery cell according to claim 1 , wherein each of the first welds extends along a radial direction of the first through hole.

5. A depth of the first weld in an axial direction of the first through hole is h, and a minimum pitch between the first weld and the first through hole in a radial direction of the first through hole is d; The battery cell according to claim 1 , wherein d and h satisfy 0.1≦h / d≦0.

6.

6. The battery cell according to claim 5 , wherein d and h satisfy 0.2≦h / d≦0.

5.

7. The battery cell of claim 5 , wherein 1.6 mm≦d≦5.5 mm.

8. The battery cell according to claim 1 , wherein a projection of the first through hole at least partially overlaps a projection of the second through hole in an axial direction of the first through hole.

9. The battery cell according to claim 1 , wherein a projection of the first through hole is located within a projection of the second through hole in an axial direction of the first through hole.

10. 2 . The battery cell according to claim 1 , wherein a diameter of the first through hole is D1, a diameter of the second through hole is D2, and D1 and D2 satisfy 65%≦D1 / D2≦95%.

11. The battery cell of claim 10 , wherein D2≧D1+0.2 mm.

12. a current collecting part for electrically connecting the electrode terminal and the first tab, The battery cell according to claim 1 , wherein the current collecting component includes a third through hole, and at least a portion of the third through hole is provided between the first through hole and the second through hole.

13. The battery cell according to claim 12 , wherein a projection of the third through hole in an axial direction of the first through hole is smaller than a projection of the second through hole.

14. The battery cell according to claim 12 , wherein a projection of the third through hole in an axial direction of the first through hole is larger than a projection of the first through hole.

15. The battery cell of claim 12, wherein in an axial direction of the first through hole, a projection of the first through hole is located within a projection of the third through hole, and a projection of the third through hole is located within a projection of the second through hole.

16. The battery cell according to claim 12 , wherein the first through hole, the second through hole and the third through hole are arranged coaxially.

17. 2. The battery cell according to claim 1, wherein the electrode terminal includes a seal plate and a terminal body, the terminal body is provided with the first through hole, and the seal plate is connected to the terminal body and is used to seal the first through hole.

18. the terminal body includes a recess and a connection portion located on a side of the recess facing the electrode assembly, the first through hole passes through the connection portion, and the connection portion realizes an electrical connection with the first tab by at least one first weld portion; The battery cell of claim 17 , wherein at least a portion of the seal plate is received in the recess.

19. 2. The battery cell according to claim 1, wherein the case includes a cylindrical body and a lid body connected to the cylindrical body, the cylindrical body is installed so as to surround an outer periphery of the electrode assembly, the lid body is provided with an electrode lead-out hole, and the electrode terminal is installed in the electrode lead-out hole.

20. The battery cell according to claim 19 , wherein the lid and the cylindrical body are integrally molded.

21. 20. The battery cell of claim 19, wherein the electrode assembly further includes a second tab, the second tab being opposite in polarity to the first tab, and the second tab being electrically connected to the lid.

22. 22. The battery cell of claim 21, wherein the first tab is located at an end of the electrode assembly toward the electrode terminal, and the second tab is located at an end of the electrode assembly away from the electrode terminal.

23. 22. The battery cell of claim 21, wherein the second tab is a negative tab and the base material of the case is steel.

24. 20. The battery cell of claim 19, wherein the cylindrical body has an opening at an end remote from the lid, the battery cell further including a cover plate for sealing the opening.

25. A battery comprising a plurality of the battery cells of any one of claims 1 to 24.

26. 26. A power consuming device comprising the battery of claim 25, the battery being adapted to provide electrical energy.

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