Battery cell assembly method, battery cell, and battery pack

Abstract

The application provides a battery cell assembling method, a battery cell and a battery pack. The battery cell assembling method comprises the following steps: providing a connecting piece and an electrode assembly; electrically connecting a first tab with a first connecting part and a second tab with a second connecting part; providing a cover plate; placing the second connecting part on at least one side of the cover plate in a second direction, and electrically connecting the first connecting part with a pole; the second direction is the width direction of the cover plate; turning over the connecting part so that the second connecting part and the main body move to the side away from the cover plate of the first connecting part; and turning over the second connecting part so that the second connecting part is parallel to the first connecting part. The battery cell assembling method, the battery cell and the battery pack provided by the application have good safety performance and power performance.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to a method for assembling a battery cell, a battery cell, and a battery pack. Background Technology

[0002] In the development of battery technology, the market is placing increasingly higher demands on the power performance and safety performance of individual battery cells. The power performance of a battery cell directly affects the power output capability, fast charging adaptability, and response performance under high-rate charge and discharge conditions of electrical devices. At the same time, in the pursuit of high power performance, battery cells often need to withstand large charge and discharge currents and have a more compact internal layout, which increases the risk of thermal runaway and internal short circuits in battery cells.

[0003] It is evident that the power performance and safety performance of a battery cell are both crucial to the battery cell itself. Therefore, how to improve the power performance and safety performance of a battery cell has become an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a battery cell assembly method, a battery cell, and a battery pack, so as to at least partially solve the problem of how to improve the power performance and safety performance of battery cells.

[0005] To achieve the above objectives, the first aspect of the present invention provides a method for assembling a battery cell, comprising:

[0006] A connector and an electrode assembly are provided; the connector is a sheet-like structure, including a first connecting part, a busbar connecting part and a second connecting part, the second connecting part being electrically connected to the first connecting part through the busbar connecting part; the electrode assembly includes a main body, with a first electrode tab and a second electrode tab of the same polarity respectively led out from opposite ends of the main body; The first electrode tab is electrically connected to the first connecting part, and the second electrode tab is electrically connected to the second connecting part; A cover plate is provided, wherein the cover plate is insulatedly connected to an electrode post; The second connecting part is placed on at least one side of the cover plate along the second direction, and the first connecting part is electrically connected to the pole post; the second direction is the width direction of the cover plate; Flip the busbar connection so that the second connection and the main body move to the side of the first connection away from the cover plate; Flip the second connecting part so that it is parallel to the first connecting part.

[0007] Based on the same inventive concept, the second aspect of the present invention also provides a battery cell, which is formed using the battery cell assembly method described in the first aspect.

[0008] Based on the same inventive concept, a third aspect of the present invention also provides a battery pack, including battery cells as described in the second aspect.

[0009] As can be seen from the above, the battery cell assembly method, battery cell, and battery pack provided by this invention, due to the integrally formed structure of the connectors, eliminate the need for alignment, assembly, and multi-point step-by-step alignment correction of multiple separate parts during battery cell assembly. The assembly benchmark is unique, and positioning is quick and convenient. Combined with a standardized assembly method, redundant operations such as on-site tooling switching, manual alignment re-inspection, and step-by-step auxiliary fixing can be significantly reduced. This simplifies the entire on-site mass production assembly process, including electrical connection, bending, and connector pre-assembly, lowering the difficulty of on-site process control and the barrier to manual operation. Simultaneously, it effectively shortens the overall assembly cycle time of battery cells and reduces assembly station time.

[0010] Meanwhile, standardized assembly methods can ensure the quality of electrical connections between electrode assemblies, connectors, and terminals, which helps improve the power performance and safety performance of individual battery cells. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in this invention or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only embodiments of this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 This is a schematic diagram of a battery cell with a first structure according to an embodiment of the present invention; Figure 2 This is a schematic diagram of a battery cell with a second structure according to an embodiment of the present invention; Figure 3 This is a schematic diagram of a connector with a first structure according to an embodiment of the present invention; Figure 3a for Figure 3 An enlarged schematic diagram of part A in the diagram; Figure 3b for Figure 3 An enlarged schematic diagram of part B in the diagram; Figure 4 This is a schematic diagram of the connection between the connector and the electrode assembly in the first state of the first structure according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the connection between the connector and the electrode assembly in the second state of the first structure of the present invention. Figure 5a for Figure 5 An enlarged schematic diagram of part D in the diagram; Figure 5b for Figure 5 An enlarged schematic diagram of part C in the diagram; Figure 6 This is a schematic diagram of a connector in a first state according to a first structure of an embodiment of the present invention; Figure 6a for Figure 6 An enlarged schematic diagram of part F in the diagram; Figure 6b for Figure 6 An enlarged schematic diagram of part E in the diagram; Figure 7 This is a schematic diagram of a connector with a second structure according to an embodiment of the present invention; Figure 8 This is a schematic diagram of the connection between the connector and the electrode assembly in the first state of the second structure according to an embodiment of the present invention; Figure 8a for Figure 8 An enlarged schematic diagram of part G in the diagram; Figure 9 This is a schematic diagram of the connection between the connector and the electrode assembly in the second state of the second structure according to an embodiment of the present invention; Figure 10 This is a schematic diagram showing the separation of the connectors in the third structure according to an embodiment of the present invention; Figure 11 This is a schematic diagram of the connector after splicing according to the third structure of this invention; Figure 12 This is a schematic diagram showing the separation of the connectors in the fourth structure according to an embodiment of the present invention; Figure 12a for Figure 12 An enlarged schematic diagram of part H in the diagram; Figure 12b for Figure 12 An enlarged schematic diagram of part J in the diagram; Figure 13 This is a schematic diagram of the connector after splicing according to the fourth structure of this invention; Figure 13a for Figure 13 An enlarged schematic diagram of part K in the diagram; Figure 14 This is a schematic diagram showing the separation of the connectors in the fifth structure according to an embodiment of the present invention; Figure 15 This is a schematic diagram of the connector after splicing according to the fifth structure of this invention; Figure 16 This is a schematic diagram of a battery cell with a third structure according to an embodiment of the present invention; Figure 17 This is an exploded schematic diagram of a battery cell with the third structure according to an embodiment of the present invention; Figure 18 This is a schematic diagram of the internal portion of a battery cell with a third structure according to an embodiment of the present invention; Figure 18a for Figure 18 An enlarged schematic diagram of the L portion; Figure 18b for Figure 18 An enlarged schematic diagram of part M in the diagram; Figure 19 This is a schematic diagram of the process flow of a battery cell with a third structure according to an embodiment of the present invention; Figure 20 This is a schematic diagram comparing the charging temperature rise of Example 1, Example 2, Comparative Example 1, and Comparative Example 2. Figure 21 This is a schematic diagram comparing the discharge temperature rise of Example 1, Example 2, Comparative Example 1, and Comparative Example 2; Figure 22 This is a schematic diagram of the first insulating bracket according to an embodiment of the present invention; Figure 23 This is a schematic diagram of the second insulating bracket and connector according to an embodiment of the present invention; Figure 24 This is a schematic diagram of the internal portion of a battery cell with the fourth structure according to an embodiment of the present invention; Figure 25 This is a schematic diagram of the outer surface of the insulating side plate according to an embodiment of the present invention; Figure 26 This is a schematic diagram of the inner side surface of the insulating side plate according to an embodiment of the present invention; Figure 27 This is a cross-sectional view of the internal portion of a battery cell with the fifth structure according to an embodiment of the present invention; Figure 27a for Figure 27 An enlarged schematic diagram of part N in the diagram; Figure 27b for Figure 27 An enlarged schematic diagram of part P in the diagram; Figure 27c for Figure 27 An enlarged schematic diagram of another structure of the N part; Figure 28 This is a schematic diagram of a second insulating support and cover plate according to another embodiment of the present invention; Figure 29 This is a schematic diagram comparing the charging temperature rise of Example 3, Example 4, Comparative Example 3, and Comparative Example 4; Figure 30 This is a schematic diagram comparing the discharge temperature rise of Example 3, Example 4, Comparative Example 3, and Comparative Example 4; Figure 31 This is a schematic diagram of the interior of the housing and insulating film according to an embodiment of the present invention; Figure 32 This is a schematic diagram of the insulating film according to an embodiment of the present invention; Figure 33 This is a schematic flowchart of a battery cell assembly method according to an embodiment of the present invention; Figure 34 This is a schematic diagram of the connector of the present invention after the merging connection part is flipped toward the side wall of the main body. Detailed Implementation

[0013] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0014] It should be noted that, unless otherwise specifically stated, the relative arrangement of components, numerical expressions, and values ​​set forth in these embodiments do not limit the scope of the invention.

[0015] At the same time, it should be understood that, for ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn according to actual scale.

[0016] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0017] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this invention should have the ordinary meaning understood by those skilled in the art. The terms "first," "second," and similar terms used in the embodiments of this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word covers the element or object listed after the word and its equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0018] With the rapid development of the new energy industry, lithium-ion batteries are widely used in electric vehicles, energy storage equipment and other fields due to their advantages such as high energy density and long cycle life.

[0019] like Figure 1In some embodiments, the battery cell includes a housing 100 and an electrode assembly 300. The housing 100 includes a shell 102 and a cover plate 101. One end of the shell 102 has a shell opening 1021, and the cover plate 101 is closed and connected to the shell opening 1021 to form a receiving cavity 103 within the housing 100. The electrode assembly 300 is disposed within the receiving cavity 103. The electrode assembly 300 includes a body 301, and a positive electrode tab 302a and a negative electrode tab 302b are led out from the end face of the body 301 facing the cover plate 101. The cover plate 101 is insulated from two terminals 200. One terminal 200 is electrically connected to the positive electrode tab 302a through a positive electrical connection piece 600a to form the positive electrode of the battery cell; the other terminal 200 is electrically connected to the negative electrode tab 302b through a negative electrical connection piece 600b to form the negative electrode of the battery cell. The positive and negative terminals of a battery cell are used for electrical connection to an external circuit (e.g., a bus or load).

[0020] Based on the foregoing, it can be understood that in the structural design of lithium-ion batteries, the tab 302 (including the positive tab 302a and the negative tab 302b) is an important component, and its function is to realize the export and import of the internal current of the battery cell.

[0021] like Figure 2 In some embodiments, housing openings 1021 are respectively provided at opposite ends of housing 102. Each housing opening 1021 is covered and connected to a cover plate 101, and each cover plate 101 is insulated and connected to a terminal post 200. A positive electrode tab 302a is led out from the end face of the main body 301 facing one of the cover plates 101 and is electrically connected to the terminal post 200 on the cover plate 101 through a positive electrical connection piece 600a; a negative electrode tab 302b is led out from the end face of the main body 301 facing the other cover plate 101 and is electrically connected to the terminal post 200 on the cover plate 101 through a negative electrical connection piece 600b.

[0022] In both of the aforementioned battery cell structures, the positive tab 302a of the electrode assembly 300 is led out from the same end face of the main body 301, and the negative tab 302b is also led out from the same end face of the main body 301. For this type of battery cell, the internal charge needs to be transferred from the end furthest from the tab 302 to the tab 302, and its maximum transfer path is approximately the length of the main body 301. The charge transfer path is relatively long, the current distribution is uneven, and the internal resistance of the battery is significantly increased. This is particularly noticeable for longer battery cells (e.g., blade batteries, where the length can exceed 1000 mm).

[0023] Higher internal resistance not only exacerbates energy loss (e.g., ohmic heat loss) during the charging and discharging of individual battery cells, but also reduces the overall charging and discharging efficiency of the battery cells, especially under high-rate charging and discharging conditions. Furthermore, when the internal resistance of a battery cell is high, localized excessive temperature rise is likely to occur near the tab 302 during charging and discharging. This not only accelerates the side reactions between the electrode material and the electrolyte, leading to faster capacity decay and shortening the cycle life of the battery cell, but may also trigger safety hazards such as thermal runaway, seriously affecting the reliability and safety performance of the battery cell.

[0024] To address the aforementioned problems, the present invention provides improvements to the battery cell.

[0025] like Figure 3 , Figure 3a , Figure 3b , Figure 4 and Figure 5 This invention provides a connector 400, including: a first connecting portion 401 for electrical connection with a tab 302 of an electrode assembly 300; the first connecting portion 401 includes components along a first direction (e.g., ...). Figure 3 The first outer edge 4016 extends in the X direction (the first direction is the width direction of the tab 302); the second connecting portion 402 is disposed apart from the first connecting portion 401 to form a receiving space 408 for accommodating the electrode assembly 300 between the first connecting portion 401 and the second connecting portion 402; the second connecting portion 402 is used to electrically connect with the tab 302 of the electrode assembly 300, and the second connecting portion 402 includes a second outer edge 4024 extending in the first direction; one of the first connecting portion 401 and the second connecting portion 402 is used to electrically connect with the electrode post 200; a busbar connecting portion 403 is used to electrically connect the second connecting portion 402 to the first connecting portion 401, and the busbar connecting portion 403 is bendably connected to the first outer edge 4016 and the second outer edge 4024 respectively; the connector 400 includes a first state and a second state. When the connector 400 is in the first state, the first connecting portion 401, the busbar connecting portion 403 and the second connecting portion 402 extend in the second direction (e.g., the width direction of the tab 302). Figure 3 When the connector 400 is in the second state, the first connecting part 401 and the second connecting part 402 are extended along a third direction (e.g., the Y direction); Figure 3 The Z-direction is spaced apart; the first direction, the second direction, and the third direction are perpendicular to each other, and the third direction is the thickness direction of the first connecting part 401.

[0026] For example, the first connecting portion 401, the second connecting portion 402, and the busbar connecting portion 403 can be polygonal sheet structures, such as rectangular sheet structures or trapezoidal sheet structures. The trapezoidal first connecting portion 401 can distribute stress more evenly when under load, improving the overall fatigue resistance of the connector 400 (tested to extend cycle life by 10%). For example, the first connecting part 401, the bus connecting part 403 and the second connecting part 402 can be bent by means of integral molding connection, welding or pressing connection.

[0027] For example, the first connecting part 401 and the electrode tab 302 can be electrically connected by welding (e.g., ultrasonic welding and / or laser welding) or adhesive bonding; similarly, the second connecting part 402 and the electrode tab 302 can be electrically connected by welding or adhesive bonding. The connector 400 can also be electrically connected to the electrode post 200 by welding (e.g., laser welding) or adhesive bonding.

[0028] For example, the thickness of connector 400 can be from 0.6 mm to 3 mm. When connector 400 is used for a high-rate fast-charging battery cell, the thickness of connector 400 can be from 2 mm to 3 mm; when connector 400 is used for a conventional battery cell, the thickness of connector 400 can be from 0.6 mm to 2 mm.

[0029] It should be noted that, at least in this embodiment, the connector 400 is applicable to the electrode assembly 300 with tabs 302 extending from opposite ends (that is, positive tab 302a and negative tab 302b are extended from one end face of the main body 301 of the electrode assembly 300, and positive tab 302a and negative tab 302b are also extended from the other end face).

[0030] like Figure 4 When the connector 400 is in the first state, the first connecting portion 401, the busbar connecting portion 403, and the second connecting portion 402 are unfolded along the second direction. At this time, the connector 400, the electrode assembly 300 to be assembled, and the cover plate 101 connected to the pole post 200 can be placed on a supporting surface (e.g., the surface of a support platform), the pole post 200 is placed below the connector 400, and the main body 301 of the electrode assembly 300 to be assembled is placed flat in the receiving space 408 between the first connecting portion 401 and the second connecting portion 402. Taking the positive electrode tab 302a of the electrode assembly 300 as an example, the positive electrode tab 302a located at one end of the main body 301 is folded up above the first connecting portion 401 and electrically connected to the first connecting portion 401; the positive electrode tab 302a located at the opposite end of the main body 301 is folded up above the second connecting portion 402 and electrically connected to the second connecting portion 402. Then, the first connecting part 401 can be electrically connected to the pole 200.

[0031] like Figure 5 After the terminal post 200, connector 400, and electrode assembly 300 are electrically connected, the busbar connection 403 and the main body 301 can be flipped so that the second connection 402 moves from one side of the first connection 401 to above the first connection 401, and the main body 301 changes from being flat to being vertical. At this time, the connector 400 is in the second state, and the cover plate 101 connected to the terminal post 200 is located at one end of the electrode assembly 300. For the battery cell using the connector 400 of this embodiment, since the resistance of the busbar connection 403 is less than the internal resistance of the electrode assembly 300, current can flow from inside the main body 301 to both ends, and is transmitted to the first connection 401 and the second connection 402. The first connection 401 and the second connection 402 combine through the busbar connection 403 and then transmit the current to the terminal post 200. As can be seen, the maximum charge transport path within a single battery cell is only about half the length of the main body 301, which can significantly shorten the charge transport path, effectively reduce the overall DC internal resistance (DCIR) of the battery cell, and improve rate performance and energy conversion efficiency. These beneficial effects are particularly pronounced for longer battery cells.

[0032] It should be noted here that, as Figure 4 The busbar connector 403 and the first outer edge 4016 of the first connector 401 can be bent and connected. When the connector 400 switches from the first state to the second state, the bending radius of each part of the tab 302 along the first direction is the same. Therefore, in this embodiment, the connector 400 can be electrically connected to the tab 302 first, and then the first connector 401 and the busbar connector 403 can be bent perpendicular to each other. During the bending process, the tab 302 is subjected to uniform force along the first direction, making it less prone to tearing.

[0033] It should also be noted that, understandably, during the charging and discharging process of a battery cell, the tab 302 is usually a concentrated heat source, and the connecting pieces (including the positive connecting piece 600a and the negative connecting piece 600b) connected to the tab 302 can help dissipate heat from the tab 302. However, if... Figure 1 and Figure 2 As can be seen, the connecting piece is only located between the terminal post 200 and the tab 302, and its surface area is small, so its effective heat dissipation area is also small. In contrast, the connector 400 of this embodiment includes a first connecting part 401, a second connecting part 402, and a current-combining connecting part 403, which has a larger effective heat dissipation area. In particular, the current-combining connecting part 403 can form a structure similar to a heat dissipation fin, so that the connector 400 can form an efficient longitudinal and transverse composite heat dissipation network at both ends and the middle component of the battery cell.

[0034] In the embodiment of the present invention, when the connector 400 is in the first state, the first connecting part 401, the busbar connecting part 403, and the second connecting part 402 are flattened. When the tab 302 of the electrode assembly 300 is electrically connected to the first connecting part 401 and the second connecting part 402, and when the first connecting part 401 or the second connecting part 402 is electrically connected to the electrode post 200, the connection interface can have high stability and consistency, thereby improving the connection reliability between the connector 400, the electrode assembly 300, and the electrode post 200, reducing the risk of poor contact, reducing contact resistance, and improving the overall performance of the battery cell using the connector 400 of this embodiment, such as structural integrity and electrochemical performance stability.

[0035] After the terminal post 200, connector 400, and tab 302 are electrically connected, the connector 400 can be switched to a second state so that the cover plate 101 connected to the terminal post 200 is located at one end of the electrode assembly 300, so as to facilitate its assembly into the housing 102. In a battery cell using the connector 400 of this embodiment, the internal current can flow to the first connection portion 401 and the second connection portion 402 located at opposite ends of the electrode assembly 300, and then be combined and transmitted to the terminal post 200 through the low-resistance busbar connection portion 403. This helps to shorten the charge transport path inside the battery cell, reduce DC internal resistance, improve charging and discharging efficiency, and make the battery cell perform better under high-current charging and discharging scenarios.

[0036] Meanwhile, the connector 400 in this embodiment includes a first connecting part 401, a second connecting part 402 and a busbar connecting part 403, which has a large effective heat dissipation area, so that the heat generated by the electrode assembly 300 can be quickly transferred from its interior to the external module structure, which can effectively suppress local overheating of the battery cell, improve thermal stability and reduce the risk of thermal runaway.

[0037] like Figure 3a and Figure 3b In some embodiments, the connector 400 further includes a first bending portion 404 and a second bending portion 405. The confluence connection portion 403 includes a third outer edge 4033 extending along the length direction. The first bending portion 404 and the second bending portion 405 are respectively bent and connected to the third outer edge 4033. The confluence connection portion 403 is bent and connected to the first outer edge 4016 through the first bending portion 404, and is bent and connected to the second outer edge 4024 through the second bending portion 405.

[0038] For example, the first bending portion 404 can be bent to the first connecting portion 401 and the busbar connecting portion 403 by means of integral molding, welding or pressing; similarly, the second bending portion 405 can be bent to the second connecting portion 402 and the busbar connecting portion 403 by means of integral molding, welding or pressing.

[0039] For example, the first bending portion 404 and the second bending portion 405 can be polygonal sheet structures, such as rectangular sheet structures, triangular sheet structures or trapezoidal sheet structures.

[0040] For example, the edge of the first bend 404 connected to the first connecting portion 401 and the edge of the first bend 404 connected to the confluence connecting portion 403 can be adjacent edges or edges spaced apart.

[0041] Taking the first bend 404 as an example, as follows: Figure 5 and 5a It can be seen that when the connector 400 is in the second state, the first bent part 404 is located on the side of the first connecting part 401 away from the pole post 200, the busbar connection part 403 is located on the side of the smaller side wall of the main body 301, and the busbar connection part 403 can be parallel to the side wall.

[0042] If the busbar connection 403 is directly connected to the first outer edge 4016 of the first connection 401, in order to ensure that the busbar connection 403 is parallel to the side wall of the main body 301, the effective connection area between the busbar connection 403 and the first connection 401 will be too small, resulting in poor connection reliability and high resistance. In order to ensure that the busbar connection 403 and the first connection 401 have a large effective connection area, the busbar connection 403 will be perpendicular to the side wall of the main body 301. This will not only increase the width of the entire battery cell and reduce the energy density of the battery cell, but also increase the risk of the busbar connection 403 scratching the electrode assembly 300.

[0043] To avoid the aforementioned problems, in this embodiment, the third outer edge 4033 of the busbar connection portion 403 is connected to the first outer edge 4016 of the first connecting portion 401 via the first bending portion 404. Since the first bending portion 404 is parallel to both the third outer edge 4033 and the first outer edge 4016, a large effective connection area can be ensured between the first bending portion 404 and the first connecting portion 401, and between the first bending portion 404 and the busbar connection portion 403. This helps improve the connection reliability of the three components and reduce resistance. Simultaneously, the busbar connection portion 403 can be flipped to be parallel to the side wall of the main body 301. Therefore, when the connector 400 is in the second state, the dimension of the busbar connection portion 403 along the first direction is its thickness, resulting in a smaller dimension. This helps save internal space in the battery cell and increase the energy density of the battery cell. Furthermore, since the larger surface area of ​​the busbar connection portion 403 faces the main body 301, even if this surface contacts the surface of the main body 301, it is less likely to scratch the electrode assembly 300, thus improving the safety of the battery cell.

[0044] The beneficial effects of providing the second bending portion 405 are similar to those of providing the first bending portion 404, and will not be repeated here.

[0045] like Figure 3a and Figure 3b In some embodiments, at least one of the first bend 404 and the second bend 405 is connected to the third outer edge 4033 near its end.

[0046] Taking the second bend 405 as an example, such as Figure 5b The smaller the distance between the end of the second bend 405 and the end of the third outer edge 4033, the smaller the height of the busbar connection 403 protruding from the second connection 402 in the direction away from the main body 301 when the connector 400 is in the second state. This helps to save third-direction space inside the battery cell, thereby increasing the energy density of the battery cell.

[0047] like Figure 6 , Figure 6a and Figure 6b In some embodiments, when the connector 400 is in the first state, the portion of the first connecting part 401 connected to the tab 302 and the portion of the second connecting part 402 connected to the tab 302 are both located on the same side of the third outer edge 4033; the first bent part 404 is connected to the position near the end of the first outer edge 4016.

[0048] It should be noted that, as Figure 4 Along the first outer edge 4016, the first bend 404 is close to one end, and the tab 302 is close to the other end.

[0049] by Figure 6Taking the structure and orientation shown as an example, when the connector 400 is in the first state, the part of the first connecting part 401 connected to the tab 302 (as shown in the dashed box in the figure) and the part of the second connecting part 402 connected to the tab 302 (as shown in the dashed box in the figure) are both located above the edge of the third outer edge 4033.

[0050] like Figure 5a The smaller the distance between the first bent portion 404 and the end of the first outer edge 4016, the smaller the size of the first connecting portion 401 protruding from the busbar connecting portion 403 in the direction away from the main body 301 in the first direction when the connector 400 is in the second state. This helps to save space in the first direction inside the battery cell, thereby increasing the energy density of the battery cell.

[0051] like Figure 6 , Figure 6a and Figure 6b In some embodiments, the second bend 405 is connected to the second outer edge 4024 near its end.

[0052] Similarly, such as Figure 5b The smaller the distance between the second bend 405 and the end of the second outer edge 4024, the smaller the size of the second connecting part 402 protruding from the busbar connecting part 403 in the direction away from the main body 301 in the first direction when the connector 400 is in the second state. This helps to save space in the first direction inside the battery cell, thereby increasing the energy density of the battery cell.

[0053] like Figure 4 In some embodiments, the first connection portion 401 includes a first region 4013 and a second region 4014 distributed along a first direction. The first region 4013 is used for electrical connection with the tab 302, and the second region 4014 is used for electrical connection with the post 200.

[0054] For example, when the first connecting portion 401 and the pole post 200 are electrically connected by welding, a second region 4014 of the surface of the first connecting portion 401 away from the pole post 200 is formed with an uneven structure 4017 to improve the weld penetration and bonding strength. The uneven structure 4017 can be formed by methods such as rolling or etching.

[0055] For example, the concave-convex structure 4017 can be formed within a circular area, the diameter of which can be 6mm to 15mm. Specifically, when the connector 400 is used for a high-rate fast-charging battery cell, the diameter of the circular area can be 8mm to 15mm; when the connector 400 is used for a conventional battery cell, the diameter of the circular area can be 6mm to 10mm.

[0056] For example, along the thickness direction of the first connecting portion 401, the maximum height difference of the concave-convex structure 4017 is 0.1 mm to 0.3 mm.

[0057] For example, the coaxiality deviation between the central axis of the circular range and the central axis of the pole 200 is ≤0.2mm to ensure welding consistency.

[0058] On the first connecting part 401, a first region 4013 for electrical connection with the tab 302 and a second region 4014 for electrical connection with the post 200 are distributed along a first direction. When the first connecting part 401 is electrically connected to the post 200, the tab 302 can be avoided from blocking the connecting area, thus ensuring the reliability of the connection between the connector 400 and the post 200.

[0059] Specifically, when the electrode post 200 and the first connecting part 401 are electrically connected by welding, if the tab 302 obstructs the welding position, some welding energy will be lost due to the melting of the tab 302. This results in the energy used to weld the electrode post 200 being less than the design value, making it prone to poor welding such as incomplete welds between the electrode post 200 and the first connecting part 401. In this embodiment, the first connecting part 401 is divided into a first region 4013 and a second region 4014. This allows the tab 302 and the electrode post 200 to be positioned separately in different regions of the first connecting part 401, reducing the risk of mutual interference and ensuring the reliability of the connection between the connector 400, the electrode assembly 300, and the electrode post 200. This also helps to reduce the contact resistance among the three components.

[0060] To further reduce the internal resistance of individual battery cells, the electrode assembly 300 can be designed as a structure comprising two main bodies 301, stacked together and electrically connected to the terminal post 200 via tabs 302. Correspondingly, the structure of the connector 400 also needs to be redesigned.

[0061] like Figure 7 , Figure 8 , Figure 8a and Figure 9In some embodiments, the second connecting portion 402 includes a first sub-portion 4021 and a second sub-portion 4022, each of which is connected to the first connecting portion 401 via a busbar connecting portion 403; the electrode assembly 300 includes a first body 301a and a second body 301b, wherein the tabs 302 extending from the first body 301a are electrically connected to the first sub-portion 4021 and the first connecting portion 401, respectively, and the tabs 302 extending from the second body 301b are electrically connected to the second sub-portion 4022 and the first connecting portion 401, respectively; the first connecting portion 401 is used for electrical connection with the electrode post 200; when the connector 400 is in a first state, the first sub-portion 4021 and the second sub-portion 4022 are located on opposite sides of the first connecting portion 401 along a second direction; when the connector 400 is in a second state, the first sub-portion 4021 and the second sub-portion 4022 are assembled to form the second connecting portion 402.

[0062] For example, for the same connector 400, the tabs 302 connected to the first sub-part 4021 and the tabs 302 connected to the second sub-part 4022 can be aligned or staggered along the second direction. When the tabs 302 are staggered, it helps to reduce the current concentration in the overlapping area of ​​the tabs 302, which can reduce the local temperature rise of the battery cell in the first step, and has been tested to reduce it by about 3°C.

[0063] For example, such as Figure 7 The first sub-part 4021 can be connected to the busbar connection part 403 via a corresponding second bend 405; similarly, the second sub-part 4022 can be connected to the busbar connection part 403 via a corresponding second bend 405. The busbar connection part 403 connected to the first sub-part 4021 and the busbar connection part 403 connected to the second sub-part 4022 can be connected to the first connection part 401 via their respective corresponding first bends 404.

[0064] It should be noted that, as Figure 8 Taking the positive electrode tab 302a as an example, for the same connector 400, its first connecting part 401 is electrically connected to the positive electrode tab 302a of the first main body 301a and the positive electrode tab 302a of the second main body 301b, its first sub-part 4021 is electrically connected to the positive electrode tab 302a at the other end of the first main body 301a, and its second sub-part 4022 is electrically connected to the positive electrode tab 302a at the other end of the second main body 301b.

[0065] like Figure 8When the connector 400 is in the first state, the first sub-part 4021, the busbar connector 403, the first connecting part 401, the busbar connector 403, and the second sub-part 4022 unfold sequentially along the second direction. The first main body 301a to be assembled is placed flat between the first sub-part 4021 and the first connecting part 401, and the second main body 301b to be assembled is placed flat between the first connecting part 401 and the second sub-part 4022. Taking the positive tab 302a of the electrode assembly 300 as an example, the positive tab 302a located at one end of the first main body 301a is folded up above the first sub-part 4021 and electrically connected to the first sub-part 4021; the positive tab 302a located at the opposite end of the first main body 301a is folded up above the first connecting part 401 and electrically connected to the first connecting part 401; the positive tab 302a located at one end of the second main body 301b is folded up above the second sub-part 4022 and electrically connected to the second sub-part 4022; the positive tab 302a located at the opposite end of the second main body 301b is folded up above the first connecting part 401 and electrically connected to the first connecting part 401. Afterwards, the first connecting part 401 can be electrically connected to the electrode post 200.

[0066] like Figure 9 After the electrode post 200, connector 400, and electrode assembly 300 are electrically connected, the bus connection 403, first body 301a, and second body 301b can be flipped so that the first sub-part 4021 and the second sub-part 4022 move from opposite sides of the first connection 401 to above the first connection 401, and the first body 301a and the second body 301b change from being flat to being vertically joined, completing the core assembly. At this time, the connector 400 is in the second state, and the cover plate 101 connected to the electrode post 200 is located at one end of the electrode assembly 300.

[0067] In this embodiment, the electrode assembly 300 includes a first body 301a and a second body 301b, which can be connected in parallel with the terminal post 200 via a connector 400. This helps to further reduce internal resistance and improve the power performance of the battery cell. Simultaneously, the electrode assembly 300 can include four positive tabs 302a (one from each opposite end of the first body 301a and one from each opposite end of the second body 301b) and four negative tabs 302b. During charging and discharging of the battery cell, the heat generation locations are more dispersed, which is more conducive to heat dissipation, further reducing the risk of thermal runaway and helping to improve the safety performance of the battery cell.

[0068] like Figure 8 and Figure 8aIn some embodiments, the second region 4014 is located on the side of the first region 4013 near the busbar connection 403; the first region 4013 includes a first sub-region 40131 and a second sub-region 40132 distributed along a second direction, the first sub-region 40131 is electrically connected to the tab 302 led out from the first body 301a, and the second sub-region 40132 is electrically connected to the tab 302 led out from the second body 301b.

[0069] For example, the first connecting portion 401 may have a hollow structure formed between the first sub-region 40131 and the second sub-region 40132, so that the first sub-region 40131 and the second sub-region 40132 are spaced apart. The first sub-region 40131 and the second sub-region 40132 are respectively electrically connected to the second region 4014.

[0070] It should be noted that, taking the positive tab 302a of the electrode assembly 300 as an example, the first sub-region 40131 is electrically connected to the positive tab 302a led out from the end of the first main body 301a near the first connecting portion 401, and the second sub-region 40132 is electrically connected to the positive tab 302a led out from the end of the second main body 301b near the first connecting portion 401.

[0071] The first region 4013 is divided into a first sub-region 40131 and a second sub-region 40132. When connecting the tabs 302 of the first body 301a and the second body 301b to the first connecting part 401, the tabs 302 of the first body 301a can be aligned and connected with the first sub-region 40131, and the tabs 302 of the second body 301b can be aligned and connected with the second sub-region 40132. This standardizes the assembly process of the electrode assembly 300 and the first connecting part 401, ensuring that both the first body 301a and the second body 301b can form a reliable connection with the first connecting part 401, thereby improving the power performance of the battery cell.

[0072] In some embodiments, the connector 400 further includes an insulating layer formed on a portion of the surface of the first connector 401 and the second connector 402, and at least a portion of the surface of the bus connector 403.

[0073] It should be noted that the insulating layer formed on the first connecting portion 401 needs to avoid the area where the first connecting portion 401 is electrically connected to the tab 302 and the post 200, the insulating layer formed on the second connecting portion 402 needs to avoid the area where the second connecting portion 402 is electrically connected to the tab 302, and the insulating layer formed on the busbar connecting portion 403 can cover the entire surface of the busbar connecting portion 403. When the insulating layer is formed by a spraying process, the portion of the insulating layer near the avoidance area can form a stepped transition structure to avoid coating accumulation.

[0074] For example, a gap of 0.5 mm to 1 mm is reserved between the insulating layer and the pre-designed electrical connection area of ​​the first connection portion 401 and the second connection portion 402 to prevent the insulating layer from interfering with the electrical connection process.

[0075] For example, the insulating layer may also be formed on at least a portion of the surface of the first bend 404 and the second bend 405.

[0076] For example, before forming the insulating layer, the surface of the connector 400 needs to be subjected to alkaline washing, acid washing and passivation processes to remove oil and oxide layers from the surface of the connector 400, ensuring that the surface cleanliness of the connector 400 meets the process requirements and is free of residual impurities.

[0077] For example, the thickness of the insulation layer can be 20μm-50μm, with a total thickness error of ≤±3μm, ensuring a balance between insulation reliability and lightweight design; the adhesion of the insulation layer meets process requirements, with no peeling or flaking; the electrical properties of the insulation layer are: withstand voltage ≥1500V AC / 1min without breakdown, and volume resistivity ≥1×10¹. 4 Ω cm, meeting the insulation requirements of individual battery cells; environmental resistance of the insulation layer: salt spray resistance ≥1000h, damp heat resistance ≥1000h, no coating failure, suitable for complex operating conditions of the whole vehicle.

[0078] Forming an insulating layer on the surface of the connector 400 can effectively reduce the risk of internal short circuits in the battery cell caused by contact between the connector 400 and the electrode assembly 300, the cover plate 101, or the housing 102. Simultaneously, it can also improve the high-voltage resistance, aging resistance, and environmental resistance of the connector 400, enabling it to achieve a stable and reliable electrical connection with the electrode 200 and the tab 302 even in harsh environments.

[0079] like Figure 6a and Figure 6b In some embodiments, an arc-shaped notch 409 is provided at the bendable connection position between the bus junction 403 and the first outer edge 4016.

[0080] For example, the arc-shaped notch 409 can form a rounded chamfer structure with a radius of 0.5 mm to 1.5 mm.

[0081] It should be noted that the arc-shaped notch 409 in this embodiment is provided at the end of the first outer edge 4016 where the first bent portion 404 is connected to the first outer edge 4016, and at the end of the third outer edge 4033 where the first bent portion 404 is connected to the third outer edge 4033.

[0082] As can be seen from the foregoing, the locations where the arc-shaped notches 409 are provided in this embodiment are all locations where bending is required. By providing the arc-shaped notches 409, cracking of the connector 400 due to stress concentration can be avoided during the bending process. At the same time, bending accuracy and positioning consistency can be improved.

[0083] like Figure 6a and Figure 6b In some embodiments, an arc-shaped notch 409 is provided at the bendable connection position between the bus junction 403 and the second outer edge 4024.

[0084] It should be noted that the arc-shaped notch 409 in this embodiment is provided at the end of the second outer edge 4024 where the second bent portion 405 is connected to the second outer edge 4024, and at the end of the third outer edge 4033 where the second bent portion 405 is connected to the third outer edge 4033.

[0085] It should be noted that the beneficial effects achieved by the arc-shaped notch 409 in this embodiment are similar to the beneficial effects achieved by the arc-shaped notch 409 located at the bendable connection position between the confluence connection portion 403 and the first outer edge 4016, as described above, and will not be repeated here.

[0086] In some embodiments, an insulating layer is applied to the surface of the connector 400.

[0087] For example, the insulation layer can be coated with ultraviolet light (UV spraying) to ensure coating uniformity. After spraying, it can be cured by UV curing lamp (e.g., wavelength 365nm, power 800W to 1200W) to form a dense insulation layer. The spraying material can be an aging-resistant coating to ensure the insulation layer meets RoHS and REACH environmental requirements, is free of harmful substances, and is compatible with power battery production processes. It can be further subdivided to suit three types of main materials for different operating conditions: for high-temperature energy storage conditions, it uses silicone-modified UV insulating varnish, which has excellent temperature resistance, does not age under long-term high temperatures, and has a volume resistivity ≥1×10¹. 4 Ω cm; Suitable for conventional, ambient temperature vehicle operating conditions, epoxy-modified UV insulating varnish with high mechanical strength, impact resistance, and adhesion up to grade 0; Suitable for lightweight, low-resistance operating conditions, polyurethane-modified UV insulating varnish with good flexibility, bending resistance, thin coating thickness, and light weight.

[0088] An insulating layer can be formed on the surface of connector 400 by a spraying process. Spraying allows the insulating layer to be formed on surfaces of connector 400 that are small in area or have complex surface structures, thus helping to achieve the most comprehensive insulation protection possible for connector 400.

[0089] It should be noted that when the first connecting part 401, the bus connecting part 403 and the second connecting part 402 are integrally formed, the connector 400 can be formed in one piece by die cutting and stamping, which can eliminate problems such as false welding of separate parts, uneven resistance and failure of splicing position from the root, and help ensure the continuous and stable current transmission of the connector 400.

[0090] However, combined Figure 8 When the integrally formed connector 400 is in the first state, its length along the second direction is too large, which will result in material waste during die-cutting and stamping. At the same time, when the connector 400 is transferred from the first state, it is also prone to bending and deformation due to its own weight, which will adversely affect the assembly of the battery cells.

[0091] To avoid the aforementioned problems, the connector 400 can be designed as a split structure, forming at least two parts during the die-cutting and stamping stage. During battery cell assembly, these two parts are then joined together as a whole and electrically connected to the electrode assembly 300 and the terminal post 200.

[0092] Specifically, the structure of the split connector 400 is described through the following embodiments.

[0093] like Figure 10 and Figure 11 In some embodiments, the connector 400 includes at least two independently formed and electrically connected portions.

[0094] For example, at least two parts can be independently formed by processes such as die cutting and stamping. When assembling a battery cell, at least two parts can be connected into a whole by means of welding or adhesive bonding, and electrical connection can be achieved between the connected parts.

[0095] In addition to the aforementioned beneficial effects, this embodiment divides the connector 400 into at least two parts, which are independently formed. This allows for more flexible layout during die-cutting and stamping, higher material utilization, and helps reduce the manufacturing cost of the connector 400. Furthermore, compared to a one-piece connector 400, the smaller dimensions of each part in this embodiment ensure higher dimensional accuracy. This reduces the risk of tearing the tabs 302 due to large dimensional errors in the connector 400 during battery cell assembly. The smaller size also facilitates material storage and transportation. During transportation, the various parts (especially the busbar connection 403) are less prone to bending and deformation due to their own weight, improving the structural stability of the connector 400. This also helps to achieve more accurate positioning of the tabs 302, the terminal post 200, and the connector 400 during battery cell assembly, ensuring the quality of their electrical connection and improving the assembly efficiency of the battery cells.

[0096] like Figure 12 , Figure 12a , Figure 12b , Figure 13 and Figure 13a In some embodiments, at least one of the bus connection portion 403 and the first connection portion 401 is independently formed from the first bending portion 404 and is electrically connected to each other.

[0097] For example, such as Figure 12a The first bending portion 404 can be integrally formed and connected with the first connecting portion 401, and can also be independently formed with the current connecting portion 403. When assembling the battery cell, the first bending portion 404 and the current connecting portion 403 need to be electrically connected by welding or adhesive bonding. Alternatively, the first bending portion 404 can be integrally formed and connected with the current connecting portion 403, and can also be independently formed with the first connecting portion 401. When assembling the battery cell, the first bending portion 404 and the first connecting portion 401 need to be electrically connected by welding or adhesive bonding. Or, the first bending portion 404, the first connecting portion 401, and the current connecting portion 403 can all be independently formed. When assembling the battery cell, the first bending portion 404 needs to be electrically connected with the first connecting portion 401 and the current connecting portion 403 by welding or adhesive bonding.

[0098] For example, taking the first bending portion 404 and the bus connection portion 403 as being formed independently, when the two are electrically connected, they can be welded or glued together at the edges where they are connected, or one of them can be provided with an additional protruding structure, and then welded or glued together with the other through the structure.

[0099] In this embodiment, the connector 400 is split into multiple independently formed parts at the first bending part 404. This ensures that the first connecting part 401 and the busbar connecting part 403 are each an integral structure, which can better ensure the connection reliability of the first connecting part 401 with the tab 302 and the pole 200, and also ensure that the internal resistance of the busbar connecting part 403 is relatively uniform.

[0100] It should be noted that the connector 400 can also be disassembled into multiple independently formed parts at the second bend 405. Following this approach, the connector 400 can be disassembled into various different combinations, for example: The connector 400 can be disassembled into a first connecting part 401, a first bending part 404, a confluence connecting part 403, a second bending part 405, and a second connecting part 402, which are formed independently; or, The first bending portion 404 of the above five parts can be integrally formed with either the first connecting portion 401 or the busbar connecting portion 403, and independently formed with the other, and the second bending portion 405 can be independently formed with the busbar connecting portion 403 and the second connecting portion 402 respectively; or, The first bending portion 404 of the above five parts can be integrally formed with either the first connecting portion 401 or the busbar connecting portion 403, and independently formed with the other; and the second bending portion 405 can be integrally formed with either the busbar connecting portion 403 or the second connecting portion 402, and independently formed with the other; or, The first bending portion 404 of the above five parts can be integrally formed with either the first connecting portion 401 or the busbar connecting portion 403, and independently formed with the other, and the second bending portion 405, the busbar connecting portion 403, and the second connecting portion 402 are integrally formed and connected; or, The first bending portion 404 of the above five parts is formed independently of the first connecting portion 401 and the busbar connecting portion 403, and the second bending portion 405 is integrally formed with either the busbar connecting portion 403 or the second connecting portion 402, and is formed independently of the other; or, The first bending portion 404 in the above five parts is formed independently with the first connecting portion 401 and the busbar connecting portion 403, and the second bending portion 405, the busbar connecting portion 403 and the second connecting portion 402 are integrally formed and connected; or, The first bending portion 404, the busbar connection portion 403, and the first connecting portion 401 in the above five parts are integrally formed and connected, and the second bending portion 405 is integrally formed with either the busbar connection portion 403 or the second connecting portion 402, and is formed independently with the other; or... The first bending part 404, the busbar connection part 403 and the first connecting part 401 of the above five parts are integrally formed and connected, and the second bending part 405 is formed independently from the busbar connection part 403 and the second connecting part 402 respectively.

[0101] like Figure 12a and Figure 13a In some embodiments, the first bending portion 404 is integrally formed and connected with the first connecting portion 401, and a connecting protrusion 406 is formed on the edge of the first bending portion 404 adjacent to the first connecting portion 401. The connecting protrusion 406 and the first bending portion 404 can be bent and connected; the confluence connection portion 403 is connected to the connecting protrusion 406.

[0102] For example, the connecting protrusion 406 can be a polygonal sheet structure.

[0103] For example, the thickness of the connecting protrusion 406 may be equal to or less than the thickness of other areas of the first bend 404.

[0104] For example, the position of the bus connector 403 for connecting with the connecting protrusion 406 may be provided with a connecting groove 407, so that at least a portion of the connecting protrusion 406 can be fitted into the connecting groove 407, so that the bus connector 403 and the connecting protrusion 406 can be accurately positioned and connected, avoiding misalignment.

[0105] In this embodiment, the connecting protrusion 406 can be designed to be integrally formed and connected with the first bending portion 404. Therefore, when bending the connector 400, the integrally formed connection between the connecting protrusion 406 and the first bending portion 404 can be bent, without having to bend at the splicing position of the first bending portion 404 and the busbar connection portion 403. When bending the split connector 400, cracking at the splicing position can be effectively prevented, ensuring the structural stability and charge transmission reliability of the connector 400.

[0106] It should be noted that in the split connector 400, a connecting protrusion 406 and a connecting groove 407 can be provided at any splicing position to achieve precise positioning during splicing.

[0107] like Figure 14 and Figure 15 In some embodiments, the bus connector 403 includes independently formed third sub-parts 4031 and fourth sub-parts 4032, which are electrically connected end to end along the length of the bus connector 403.

[0108] It should be noted that, in addition to the third sub-part 4031 and the fourth sub-part 4032, the bus connector 403 may also include other parts. That is, a bus connector 403 can be divided into multiple parts and formed separately, and then the parts can be connected end to end in sequence by welding or adhesive bonding to form a complete bus connector 403.

[0109] by Figure 14 Taking the structure shown as an example, in the connector 400, the part with a larger length and smaller width is the busbar connector 403, which is more prone to bending deformation. To avoid this problem, this embodiment divides the busbar connector 403 into a third sub-part 4031 and a fourth sub-part 4032 along its length to reduce the length of individual components of the busbar connector 403. Furthermore, compared to the busbar connector 403 being integrally formed and connected to both the first connector 401 and the second connector 402, the third sub-part 4031 is integrally formed and connected only to the first connector 401, and the fourth sub-part 4032 is integrally formed and connected only to the second connector 402. This reduces the impact of the weight of other structural components on the third sub-parts 4031 and the fourth sub-part 4032, further reducing the risk of bending deformation and facilitating material management.

[0110] like Figure 10 and Figure 11 In some embodiments, the first connecting portion 401 includes a fifth sub-portion 4011 and a sixth sub-portion 4012 that are formed independently. The fifth sub-portion 4011 and the sixth sub-portion 4012 are joined and electrically connected along a second direction. A portion of the second region 4014 is disposed in the fifth sub-portion 4011 and another portion is disposed in the sixth sub-portion 4012.

[0111] For example, the first region 4013 may include a first sub-region 40131 and a second sub-region 40132. The first sub-region 40131 may be located in the fifth sub-part 4011, and the second sub-region 40132 may be located in the sixth sub-part 4012.

[0112] by Figure 10 Taking the structure shown as an example, the first connecting part 401 is divided into a fifth sub-part 4011 and a sixth sub-part 4012. Then the connector 400 can be roughly divided into two parts of the same length. The length of each part is about half the length of the integrally formed connector 400. Since the number of structural parts that are disassembled in the connector 400 is small, the splicing process of the connector 400 itself can be simplified. It can also effectively reduce the length of the single structural part that makes up the connector 400, which helps to improve the dimensional accuracy of the single structural part and reduce the risk of bending deformation.

[0113] In some embodiments, an insulating layer is also formed on the surface of the split connector 400.

[0114] It should be noted that, for the insulation layer formed on the split connector 400, when the various parts of the connector 400 need to be welded together, in addition to avoiding the electrical connection positions of the connector 400 with the tab 302 and the post 200 as mentioned above, the insulation layer also needs to avoid the splicing positions of the connector 400.

[0115] Based on the same inventive concept and in conjunction with the description of the connector 400 in the above embodiments, this embodiment provides a battery cell that has the corresponding technical effects of the connector 400 in the above embodiments, which will not be repeated here.

[0116] like Figure 16 , Figure 17 , Figure 18 , Figure 18a and Figure 18bThis embodiment provides a battery cell including a cover plate 101, a terminal post 200, an electrode assembly 300, and a connector 400 as described in the above embodiments. The connector 400 is in a second state. The terminal post 200 is insulatedly connected to the cover plate 101. The electrode assembly 300 includes a main body 301. The opposite ends of the main body 301 respectively lead out tabs 302 of the same polarity. The tab 302 at one end is electrically connected to a first connecting part 401, and the tab 302 at the other end is electrically connected to a second connecting part 402. The first connecting part 401 is electrically connected to the terminal post 200.

[0117] For example, such as Figure 19 The preparation process of a single battery cell may include the following steps: A slurry containing active material is formed through a homogenization process, and the slurry is coated onto a pre-prepared metal foil surface. The coated metal foil is then rolled and die-cut to form an electrode (the active material slurry and metal foil used for the positive and negative electrode differ, but they are generally formed through the above processes). The obtained positive electrode, separator, and negative electrode are then wound or stacked, followed by a preheating and hot-pressing process to obtain an electrode assembly 300. The tabs 302 of the obtained electrode assembly 300 are electrically connected to the connector 400 by welding, and the connector 400 is electrically connected to the electrode post 200 on the cover plate 101 by welding. After welding, the connector 400 is bent (when the electrode assembly 300 includes two main bodies 301, the core assembly process is completed after bending the connector 400). Next, a bracket 500 (e.g., a first insulating bracket 501) is installed onto the connector 400, and the assembled portion is inserted into the housing 102. The housing 102 and the cover plate 101 are then perimeter welded. After welding, the parts are dried, and then electrolyte is injected into the housing 102 for the first time. After formation, electrolyte is injected into the housing 102 for the second time. Then, the electrolyte injection holes of the battery cells are sealed with sealing pins, and the sealing pins are welded in place. Finally, a capacity testing process is performed to assess the performance of the battery cells.

[0118] For example, when connector 400 is electrically connected to positive tab 302a, its material can be aluminum (series 1). When connector 400 is electrically connected to negative tab 302b, its material can be copper.

[0119] For example, the thickness of the connector 400 electrically connected to the positive tab 302a and the connector 400 electrically connected to the negative tab 302b can be the same or different.

[0120] For example, the metal foil material of the electrode sheet within the electrode assembly 300 can be a composite foil material to reduce the weight of the electrode assembly 300 and increase the energy density of the battery cell.

[0121] For example, the electrode assembly 300 can be a wound structure or a stacked structure.

[0122] For example, the size of the tab 302 can be set according to the size of the main body 301 and the capacity performance requirements of the battery cell, and the number of tabs 302 is determined according to the number of stacked layers or the number of winding folds, which is not limited here.

[0123] Understandably, during the charging and discharging process, heat generation in a battery cell is concentrated near the tab 302. Compared to battery cells where the tab 302 of the same polarity is only led out from one end of the main body 301, in this embodiment, the tabs 302 of the same polarity are led out from opposite ends of the main body 301. Therefore, the heat generation location of the battery cell is more dispersed, which is beneficial for heat dissipation. Based on the foregoing, it can be seen that the battery cell in this embodiment has a lower internal resistance, resulting in relatively less heat generation. Furthermore, the connector 400 has a larger heat dissipation area. The combination of these multiple structures further reduces the risk of thermal runaway in the battery cell, thus improving its safety performance.

[0124] The performance of the battery cells in this embodiment of the invention can be further illustrated by the following experimental data.

[0125] Example: The battery cell is blade-shaped, 500mm long, 173mm wide, and 54mm thick. Its internal electrode assembly 300 has positive tabs 302a and negative tabs 302b extending from opposite ends of the main body 301. The positive tabs 302a at both ends are electrically connected to the terminal post 200 via connectors 400 as described in the various embodiments. Both the positive tabs 302a and the connectors 400 are made of aluminum. The negative tabs 302b at both ends are electrically connected to the terminal post 200 via connectors 400 as described in the various embodiments. Both the negative tabs 302b and the connectors 400 are made of copper. The active material of the positive electrode sheet of the electrode assembly 300 includes lithium iron phosphate, and the electrode assembly 300 has a wound structure.

[0126] The connector 400, which is electrically connected to the positive electrode 302a, has a thickness of 0.8mm. The length (dimension along the first direction) of the first connecting part 401 and the second connecting part 402 is 520mm, and the width (dimension along the second direction) is 45mm. The solder mark between the connector 400 and the positive electrode 302a is approximately rectangular and has a width of 30mm.

[0127] The connector 400, which is electrically connected to the negative electrode tab 302b, has a thickness of 0.6 mm. The length of the first connecting part 401 and the second connecting part 402 is 520 mm and the width is 45 mm. The solder mark between the connector 400 and the positive electrode tab 302a is approximately rectangular and has a width of 25 mm.

[0128] The connector 400 is ultrasonically welded to the tab 302 and laser-welded to the pole post 200.

[0129] Comparative example: Compared with the above embodiment, the only difference is that the internal electrode assembly 300, with positive tab 302a and negative tab 302b, extends only from one end of the main body 301. Positive tab 302a is electrically connected to the terminal 200 via positive connecting piece 600a, and both positive tab 302a and positive connecting piece 600a are made of aluminum; negative tab 302b is electrically connected to the terminal 200 via negative connecting piece 60b, and both negative tab 302b and negative connecting piece 60b are made of copper.

[0130] Two battery cells from each of the examples and comparative examples were selected to form Example 1, Example 2, Comparative Example 1 and Comparative Example 2. The following performance tests were performed on the four examples, and the positive electrode temperature of the battery cells was collected.

[0131] I. Initial charge / discharge energy (charge / discharge sampling time is 1 second, resting time is 30 seconds, and safe temperature is 65℃) 1. Let stand at 25℃ for 5 hours, charge at 0.5CP to 3.65V at 25℃, and let stand for 30 minutes; 2. Discharge to 2.5V at 0.5CP at 25℃, and let stand for 30 minutes; 3. Charge to 3.65V at 0.5CP at 25℃, then let stand for 30 minutes; 4. Discharge to 2.5V at 0.5CP at 25℃, and let stand for 30 minutes; The battery cell was cycled through steps 3-4 above 3 times, and the average of the 3 tests was taken as the result.

[0132] 5. Charge to 3.65V at 0.5CP at 25℃, then let stand for 30 minutes; 6. Discharge at 0.5 CP to 50% SOC at 25℃, and let stand for 30 minutes; (the discharge capacity of the previous cycle is used as the standard, denoted as C0). 7. Discharge at 1C for 30 seconds at 25℃ (sampling time is 0.5 seconds), then let stand for 30 minutes; 8. Discharge to 2.5V at 0.5CP at 25℃, and let stand for 30 minutes; II. Rate charging and discharging (charging and discharging sampling time is 1 second, resting time is 30 seconds, and safe temperature is 65℃) 9. Discharge to 2.5V at 0.25CP at 25℃, and let stand for 30 minutes; 10. Charge to 3.65V at 0.25CP at 25℃, then let stand for 30 minutes; 11. Discharge to 2.5V at 0.25CP at 25℃, and let stand for 30 minutes; 12. Charge to 3.65V at 0.5CP at 25℃, then let stand for 30 minutes; 13. Discharge to 2.5V at 0.5CP at 25℃, and let stand for 30 minutes; 14. Charge to 3.65V at 0.5CP at 25℃, then let stand for 30 minutes; 15. Discharge to 2.5V at 0.5CP at 25℃, and let stand for 30 minutes; 16. Charge to 3.65V at 1CP at 25℃, then let stand for 30 minutes; 17. Charge to 3.65V at 0.5CP at 25℃, then let stand for 30 minutes; 18. Discharge to 2.5V at 1CP at 25℃, and let stand for 30 minutes; 19. Discharge to 2.5V at 0.5CP at 25℃, and let stand for 30 minutes; 20. Charge to 3.65V at 2CP at 25℃, then let stand for 30 minutes; 21. Charge to 3.65V at 0.5CP at 25℃, then let stand for 30 minutes; 22. Discharge to 2.5V at 2CP at 25℃, and let stand for 30 minutes; 23. Discharge to 2.5V at 0.5CP at 25℃, and let stand for 30 minutes; 24. Charge to 3.65V at 1CP at 25℃, then let stand for 30 minutes; 25. Discharge to 2.5V at 1CP at 25℃, and let stand for 30 minutes; 26. Discharge to 2.5V at 0.5CP at 25℃, and let stand for 30 minutes; 27. Charge to 3.65V at 2CP at 25℃, then let stand for 30 minutes; 28. Discharge to 2.5V at 2CP at 25℃ and let stand for 30 minutes.

[0133] The test data obtained from the above performance tests are shown in Table 1, and Figure 20 and Figure 21 As shown.

[0134] Table 1 Performance test data for Example 1, Example 2, Comparative Example 1, and Comparative Example 2

[0135] Test data shows that, compared to Comparative Examples 1 and 2, Examples 1 and 2 exhibit a 25% reduction in 2CP charging temperature rise, a 35% reduction in 2CP discharging temperature rise, and a 25% reduction in DCIR. This demonstrates that the battery cells in this embodiment possess better power performance, further broaden the overcurrent capability of the battery cells, and improve the thermal safety performance of the battery cells.

[0136] In some embodiments, the aspect ratio (i.e., the ratio of length to width) of the battery cell is 2.5 to 5.

[0137] For example, the length of the battery cell (i.e., the dimension along a third direction) can be 200mm to 800mm, the width of the battery cell (i.e., the dimension along a first direction) can be 80mm to 200mm, and the thickness of the battery cell (i.e., the dimension along a second direction) can be 15mm to 85mm.

[0138] For example, the aspect ratio of a single battery cell is 2.5, 3, 3.5, 4, 4.5 or 5.

[0139] Designing the aspect ratio of individual battery cells to be 2.5 to 5 allows for side-mounted arrangement, facilitating direct insertion into the battery pack. This simplifies the pack's internal structure and improves internal space utilization and energy density. It also allows for larger surface areas in the battery cells, enhancing heat dissipation. Furthermore, it ensures high structural strength, reducing the risk of bending deformation due to their own weight.

[0140] As described above, the connector 400 requires a bending process during battery cell assembly. To facilitate bending, the connector 400's structural strength is not excessively high. When subjected to external forces, the connector 400 cannot easily maintain its original shape. For example, when the first body 301a and the second body 301b are combined, or when the electrode assembly 300 is installed into the housing 102, the connector 400 is prone to shifting or warping, leading to problems such as the tabs not fitting properly. Furthermore, if the connector 400 lacks a dedicated positioning support structure within the battery cell, it is prone to loosening between the connector 400 and the tabs 302 and the terminal post 200 under vibration conditions, resulting in poor contact and decreased stability of the bus circuit.

[0141] To improve the above problems, such as Figure 17 and Figure 18 In some embodiments, a bracket 500 is provided on the surface of the cover plate 101 facing the main body 301, and the bracket 500 abuts against the end face of the main body 301.

[0142] For example, the bracket 500 may be insulated from the cover plate 101.

[0143] For example, the support 500 may be formed of an insulating material.

[0144] It should be noted that the bracket 500 can bypass the first connecting part 401 and abut against the end face of the main body 301 near the cover plate 101.

[0145] The bracket 500 abuts against the end of the main body 301, which can maintain a preset distance between the main body 301 and the cover plate 101, preventing problems such as the insertion of the electrode tab, deformation of the connector 400, scratches on the electrode tab 302 or damage to the main body 301 caused by the movement of the main body 301 along a third direction or deformation of the cover plate 101.

[0146] like Figure 18 , Figure 18a , Figure 18b and Figure 24 In some embodiments, the motor assembly in the battery cell includes a body 301, a first tab 3021, and a second tab 3022. The body 301 includes a first end face 3011 near the terminal post 200 and a second end face 3012 away from the terminal post 200. The first tab 3021 extends from the first end face 3011, and the second tab 3022 extends from the second end face 3012. The first tab 3021 and the second tab 3022 have the same polarity. A first connecting portion 401 is disposed between the terminal post 200 and the first end face 3011 and is electrically connected to the first tab 3021 and the terminal post 200. A second connecting portion 402 is disposed on the side of the second end face 3012 away from the terminal post 200 and is electrically connected to the second tab 3022. The battery cell also includes a first insulating bracket 501, which is sleeved on the second connecting portion 402 and abuts against the second end face 3012.

[0147] For example, the first insulating support 501 can be formed by injection molding.

[0148] For example, the material of the first insulating support 501 can be a high-strength insulating engineering plastic, such as PPS (polyphenylene sulfide, glass fiber reinforced), PPA (polyphthalamide, high-temperature nylon) or PA66 (glass fiber reinforced).

[0149] For example, the dimension of the first insulating bracket 501 along the second direction is 1 mm to 3 mm larger than the dimension of the second connecting portion 402 along the second direction, so that the first insulating bracket 501 can reliably wrap the second connecting portion 402 and has high structural strength.

[0150] For example, the height of the first insulating bracket 501 (i.e., the dimension along a third direction) is greater than the gap between the second connecting portion 402 and the second end face 3012.

[0151] The first insulating bracket 501 is fitted onto the second connecting part 402 and abuts against the second end face 3012. It can support the second end face 3012 and the second connecting part 402, keeping them at a preset distance. Therefore, the shape of the second tab 3022 connected to the second connecting part 402 is more stable, and the problem of tab insertion is less likely to occur.

[0152] Meanwhile, when the main body 301 expands or contracts during charging and discharging, the first insulating bracket 501 fitted on the second connecting part 402 can slide along the first direction on the second connecting part 402, thereby buffering the expansion stress of the electrode assembly 300, improving the reliability of the overall structure of the battery cell, and helping to extend the cycle life of the battery cell.

[0153] The first insulating bracket 501 provided in this embodiment is fitted onto the second connecting part 402, which helps stabilize its position within the battery cell. Simultaneously, the first insulating bracket 501 abuts against the second end face 3012 of the electrode assembly 300, providing support between the second connecting part 402 and the main body 301 of the electrode assembly 300. When the battery cell, especially the bottom end, is under pressure, the support of the second connecting part 402 prevents deformation of the electrode assembly 300 and the connector 400. It also prevents the outer casing 100 from collapsing inwards, causing overlap between the outer casing 100 and the connector 400, thus avoiding a short circuit within the battery cell. This provides insulation and short-circuit protection. Furthermore, it prevents the collapsed outer casing 100 from damaging the electrode assembly 300 and the connector 400, contributing to improved safety performance of the battery cell.

[0154] In addition, the internal structure of the battery cell is supported by the first insulating bracket 501. Since the dimensional accuracy of the first insulating bracket 501 is easy to control, it helps to ensure the consistency of the internal structure of the battery cell and provides support for the mass production of the battery cell.

[0155] like Figure 18a and Figure 22 In some embodiments, the first insulating support 501 includes two sub-supports 5011 disposed on opposite sides of the second connecting portion 402 and connected to each other along a second direction, the second direction being the thickness direction of the main body 301; at least one of the opposing surfaces of the two sub-supports 5011 is provided with a first groove 5012; when the two sub-supports 5011 are connected, the first groove 5012 is configured to accommodate a through hole of the second connecting portion 402.

[0156] For example, each of the two sub-supports 5011 may be provided with a first groove 5012. When the two sub-supports 5011 are connected, the two first grooves 5012 are combined to form a through hole that extends along the first direction; or, only one of the two sub-supports 5011 is provided with a first groove 5012. When the two sub-supports 5011 are connected, the sub-support 5011 without a first groove 5012 blocks the first groove 5012 along the second direction to form a through hole that extends along the first direction.

[0157] The first insulating support 501 is designed as two interconnectable sub-supports 5011. After the second connecting part 402 and the second tab 3022 are electrically connected, the two sub-supports 5011 are then connected to the second connecting part 402 to form the first insulating support 501. This design allows for greater flexibility in the battery cell assembly process and ensures a reliable connection between the second connecting part 402 and the second tab 3022, preventing loose connections caused by the supporting effect of the first insulating support 501.

[0158] like Figure 18a and Figure 22 In some embodiments, one of the two sub-supports 5011 is provided with a first protrusion 5013, and the other is provided with a second groove 5014; the first protrusion 5013 and the second groove 5014 are slidably fitted together along a first direction, which is the width direction of the second tab 3022.

[0159] For example, such as Figure 22 The first protrusion 5013 can be a cylindrical structure; in addition, the first protrusion 5013 can also be a polygonal column structure. The shape of the second groove 5014 matches the shape of the first protrusion 5013 so that the two form a mortise and tenon connection structure.

[0160] By setting the first protrusion 5013 and the second groove 5014, the two sub-supports 5011 can only be connected and separated by sliding relative to each other along the first direction. After the two sub-supports 5011 are connected, their relative positions along the second or third direction are fixed, making the first insulating support 501 less prone to disintegration under external force. This helps to improve the structural stability of the first insulating support 501 and can play a stable and reliable insulating support role between the second connecting part 402 and the main body 301. It is not easy to fail and helps to further improve the safety performance of the battery cell.

[0161] like Figure 18a and Figure 22In some embodiments, a first insulating bracket 501 is disposed between a busbar connection 403 and a second tab 3022, and a second bending portion 405 is connected between the busbar connection 403 and the second connection portion 402; the second bending portion 405 protrudes from the busbar connection 403 and the second connection portion 402; the first groove 5012 includes a first sub-groove 50121 and a second sub-groove 50122 that are interconnected, the second connection portion 402 is partially fitted into the first sub-groove 50121, and the second bending portion 405 is fitted into the second sub-groove 50122.

[0162] For example, the first sub-slot 50121 and the second sub-slot 50122 are perpendicular to each other.

[0163] For example, the second sub-slot 50122 is connected to the end of the first sub-slot 50121 along the second direction.

[0164] It should be noted that the second connecting part 402 partially fits into the first sub-slot 50121, meaning that the second connecting part 402 needs to extend out of the first sub-slot 50121 along the first direction and be electrically connected to the second electrode 3022.

[0165] In this embodiment, by engaging the second bending portion 405 with the second sub-groove 50122, the relative positions of the first insulating bracket 501 and the second connecting portion 402 along the second direction can be further fixed, effectively preventing the first insulating bracket 501 from shifting relative to the second connecting portion 402, ensuring that it can stably provide insulation protection for the second connecting portion 402, and providing support for the second connecting portion 402 and the main body 301.

[0166] like Figure 18 , Figure 18b and Figure 23 In some embodiments, the battery cell further includes a second insulating bracket 502 disposed between the cover plate 101 and the first end face 3011. The second insulating bracket 502 includes a bracket body 5021 connected to the cover plate 101. A first connecting portion 401 is disposed on the side of the bracket body 5021 away from the cover plate 101. The bracket body 5021 is provided with a limiting portion 5022 protruding toward the first end face 3011. The limiting portion 5022 is disposed on opposite sides of the first connecting portion 401 along a second direction, and the limiting portion 5022 abuts against the first end face 3011. The second direction is the thickness direction of the body 301.

[0167] For example, the material of the second insulating support 502 may be the same as that of the first insulating support 501.

[0168] For example, the limiting part 5022 can correspond one-to-one with the positions of the four apex corners of the first end face 3011.

[0169] For example, the limiting portion 5022 may be symmetrically arranged with respect to the axis extending in the first direction of the first connecting portion 401.

[0170] For example, the surface of the limiting part 5022 facing the first connecting part 401 may be provided with a groove. On the one hand, the first bending part 404 can be avoided by the groove, and on the other hand, the second insulating bracket 502 and the connecting member 400 can be mutually positioned by the groove and the first bending part 404.

[0171] For example, the bracket body 5021 and the limiting part 5022 can be connected by adhesive bonding, integral molding, or snap-fit.

[0172] For example, the second insulating bracket 502 can be formed by injection molding to give the second insulating bracket 502 high dimensional accuracy. The tolerance fit between the limiting part 5022 and the first connecting part 401 can be controlled within ±0.1mm to avoid abnormal noise or poor contact inside the battery cell due to excessive gap between the first connecting part 401 and the limiting part 5022.

[0173] by Figure 23 Taking the structure and orientation shown as an example, the limiting parts 5022, which are respectively set on opposite sides of the first connecting part 401, protrude from the first connecting part 401 in the third direction. The limiting parts 5022 can at least limit the first connecting part 401 in the second direction. When the battery cell is transported or under vibration, the risk of the connecting part 400 shifting can be reduced. Meanwhile, since the limiting portions 5022 on both sides of the first connecting portion 401 abut against the first end face 3011, the first insulating bracket 501 can provide relatively uniform support for the main body 301 of the electrode assembly 300, ensuring that the cover plate 101, connector 400, main body 301 and electrode tab 302 are in stable position inside the battery cell. This effectively reduces problems such as the battery cell casing 100 collapsing, connector 400 deforming or even breaking, electrode tab insertion or electrode assembly 300 being damaged by pressure. It can also prevent the connector 400 from accidentally contacting the main body 301, casing 102 and cover plate 101, preventing safety hazards such as internal short circuit or insulation breakdown in the battery cell.

[0174] like Figure 18 , Figure 18b and Figure 23 In some embodiments, the orthographic projection of the limiting portion 5022 along the second direction onto the connector 400 does not coincide with the busbar connection portion 403.

[0175] Based on the foregoing, when the connector 400 is in the first state, the busbar connection 403 is located on at least one side of the first connector 401 along the second direction. To avoid mechanical interference between the busbar connection 403 and the limiting part 5022, the limiting part 5022 needs to be positioned away from the busbar connection 403. Therefore, in this embodiment, the positioning of the limiting part 5022 is limited so that its orthographic projection along the second direction on the connector 400 does not coincide with the busbar connection 403.

[0176] like Figure 17 and Figure 18 In some embodiments, the battery cell further includes an insulating film 700, which encloses the connector 400 and the electrode assembly 300. The insulating film 700 forms an insulating film opening 701 facing the cover plate 101, and the portion of the insulating film 700 near the insulating film opening 701 is connected to the limiting portion 5022.

[0177] For example, the insulating film 700 may include a Mylar film.

[0178] For example, the insulating film 700 can be connected to the sidewall of the limiting part 5022 by means of heat fusion or adhesive bonding.

[0179] The limiting part 5022 of the second insulating bracket 502 can be reused as a fixing base for the insulating film 700. It can keep the insulating film 700 fixed in the position inside the battery cell, prevent the insulating film 700 from shifting, wrinkling or falling off, and ensure that the insulating film 700 can provide stable and reliable insulation protection for the electrode assembly 300. It can also improve the space utilization rate inside the battery cell, which is conducive to further improving the energy density of the battery cell.

[0180] like Figure 18a In some embodiments, both the first sub-part 4021 and the second sub-part 4022 are disposed on the first insulating bracket 501.

[0181] For example, the first sub-part 4021 and the second sub-part 4022 are independent of each other.

[0182] In addition to providing insulation protection for the second connecting portion 402, the first insulating bracket 501 can also constrain the first sub-part 4021 and the second sub-part 4022, preventing them from separating from each other along the second direction, which helps to maintain the stability of the internal structure of the battery cell.

[0183] like Figure 16 and Figure 17In some embodiments, the battery cell includes a housing 100 with an internal cavity 103, and the housing 100 is insulated and connected to a terminal post 200 at only one end; an explosion-proof valve 900 is provided at the end of the housing 100 where the terminal post 200 is provided and at the other end opposite to it.

[0184] For example, the housing 100 includes a housing 102 and a cover plate 101. The housing 102 may have a housing opening 1021 at only one end, and the cover plate 101 is closed and connected to the housing opening 1021. One of the two explosion-proof valves 900 of the battery cell is provided on the cover plate 101, and the other is provided at the bottom end of the housing 102 (i.e., the end away from the cover plate 101). Alternatively, the housing 102 may have housing openings 1021 at opposite ends, and the two cover plates 101 are closed and connected to the two housing openings 1021 in a one-to-one correspondence. Each cover plate 101 is provided with an explosion-proof valve 900.

[0185] By installing explosion-proof valves 900 at both ends of the battery cell, the pressure relief capacity of the battery cell can be effectively improved. When the battery cell experiences thermal runaway, the high-temperature gas inside can be released to the outside in a timely, rapid and relatively balanced manner through the two explosion-proof valves 900, reducing the risk of the outer casing 100 bulging, cracking, or even explosion, and significantly improving the explosion-proof safety and thermal runaway protection capability of the battery cell.

[0186] Furthermore, since the gas inside the battery cell can flow to both ends of the casing 100, the jet impact force and the probability of sparking caused by the gas released from the open explosion-proof valve 900 can be reduced. Even if one of the explosion-proof valves 900 becomes blocked, the other can still depressurize normally, providing safety redundancy and effectively reducing the risk of thermal runaway cascading.

[0187] like Figure 17 In some embodiments, the outer casing 100 includes a casing 102, a first cover plate 101a and a second cover plate 101b. The casing 102 has casing openings 1021 at opposite ends. The first cover plate 101a and the second cover plate 101b are connected to the two casing openings 1021 in a one-to-one correspondence. The pole post 200 is insulatedly connected to the first cover plate 101a.

[0188] It should be noted that, in this embodiment, the battery cell, the terminal 200, is only connected to the first cover plate 101a.

[0189] Compared to a housing 102 with only one housing opening 1021, the housing 102 in this embodiment has housing openings 1021 at both opposite ends, which makes the assembly process of the battery cell more flexible and facilitates mass production.

[0190] like Figure 24In some embodiments, the battery cell also includes an insulating side plate 800 disposed between the busbar connection 403 and the main body 301.

[0191] For example, the insulating side panel 800 can be formed from insulating material by an injection molding process.

[0192] When the battery cell is placed horizontally, the main body 301 of the electrode assembly 300 will directly act on the busbar connection part 403 of the connector 400. Since the busbar connection part 403 is a metal structural component, its edges may scratch the main body 301, which may cause the busbar connection part 403 to overlap with the electrode sheet inside the main body 301, causing the battery cell to have an internal short circuit.

[0193] To avoid the aforementioned problems, this embodiment provides an insulating side plate 800 between the busbar connection 403 and the main body 301. When the battery cell is placed horizontally, the main body 301 acts on the insulating side plate 800 and no longer directly contacts the busbar connection 403. Therefore, the risk of the main body 301 being scratched by the busbar connection 403 can be effectively reduced, improving the safety performance of the battery cell.

[0194] like Figure 24 and Figure 25 In some embodiments, a side plate groove 801 is formed on the surface of the insulating side plate 800 facing the busbar connection portion 403, and at least a portion of the busbar connection portion 403 is fitted into the side plate groove 801.

[0195] For example, the side plate groove 801 extends through the insulating side plate 800 in a third direction.

[0196] Based on the foregoing, it can be understood that since the connector 400 is electrically connected to the electrode assembly 300, the relative position between the busbar connection 403 and the main body 301 is relatively stable. The busbar connection 403 is at least partially embedded within the side plate groove 801, and can position the insulating side plate 800, thereby maintaining the insulating side plate 800 in a stable position within the battery cell. This effectively prevents relative movement between the insulating side plate 800 and the main body 301, and prevents scratches on the main body 301 due to edge contact between the main body 301 and the insulating side plate 800, further improving the safety performance of the battery cell.

[0197] like Figure 24 In some embodiments, the insulating side plate 800 is connected to the first insulating support 501.

[0198] For example, the insulating side plate 800 and the first insulating bracket 501 can be connected by means of heat fusion, adhesive bonding, riveting, plugging or snap-fitting.

[0199] As described above, the first insulating bracket 501 is fitted onto the second connecting part 402, thus ensuring a relatively stable relative position between the first insulating bracket 501 and the connecting part 400. The insulating side plate 800 is connected to the first insulating bracket 501, which positions the insulating side plate 800 within the battery cell, effectively preventing relative displacement between the insulating side plate 800 and the main body 301.

[0200] like Figure 24 and Figure 26 In some embodiments, the surface of the insulating side plate 800 facing the tab 302 is formed with a protruding side plate protrusion 802, and the insulating side plate 800 is connected to the first insulating support 501 through the side plate protrusion 802.

[0201] For example, the side plate protrusion 802 and the insulating side plate 800 can be connected by means of integral molding, hot melting, adhesive bonding, riveting, plugging or snap-fitting.

[0202] For example, fasteners (e.g., screws or rivets) can be installed on the insulating side plate 800 to form a side plate protrusion 802. At this time, the first insulating bracket 501 can be formed with mounting holes (e.g., smooth holes or threaded holes) that match the fasteners to connect the insulating side plate 800 to the first insulating bracket 501.

[0203] The insulating side plate 800 is connected to the first insulating support 501 through the side plate protrusion 802. This not only ensures a stable and reliable connection between the insulating side plate 800 and the first insulating support 501, but also facilitates the positioning of the two, which is conducive to standardized production and helps to improve the structural consistency of the battery cells.

[0204] like Figure 24 In some embodiments, the busbar connection 403 is disposed on at least one side of the main body 301 along a first direction, the first direction being the width direction of the tab 302; the dimension of the insulating side plate 800 along a second direction is larger than the dimension of the main body 301 along a second direction, the second direction being the thickness direction of the main body 301.

[0205] Understandably, during the charging and discharging process, the main body 301 may expand along the second direction. If the dimension of the insulating side plate 800 in the second direction is equal to or smaller than the dimension of the main body 301 in the second direction, then when the main body 301 expands, it may come into contact with the edge of the insulating side plate 800, thereby causing scratches on the main body 301.

[0206] To avoid the above problems, in this embodiment, the dimension of the insulating side plate 800 along the second direction is designed to be larger than the dimension of the main body 301 along the second direction. When the main body 301 expands, the risk of the main body 301 extending beyond the insulating side plate 800 along the second direction can be reduced, thereby reducing the risk of edge contact between the main body 301 and the insulating side plate 800, which helps to further improve the safety of the battery cell.

[0207] like Figure 24 In some embodiments, the orthographic projection of the body 301 along the first direction onto the insulating side plate 800 is located within the insulating side plate 800.

[0208] To further prevent the main body 301 from contacting the edge of the insulating side plate 800, this embodiment limits the orthographic projection of the main body 301 along the first direction onto the insulating side plate 800 to be located within the insulating side plate 800. Therefore, the main body 301 is not likely to contact the edge of the insulating side plate 800 in the width direction, nor is it likely to contact the edge of the insulating side plate 800 in the length direction. This helps to further reduce the risk of the main body 301 being scratched and further improve the safety of the battery cell.

[0209] Based on the foregoing, it can be understood that the insulating film 700 wraps around the connector 400 and the electrode assembly 300. Meanwhile, the insulating side plate 800 is disposed between the busbar connector 403 and the main body 301; therefore, it can be understood that the insulating film 700 can also wrap around the insulating side plate 800.

[0210] like Figure 24 In some embodiments, the side plate groove 801 corresponds one-to-one with the busbar connection part 403.

[0211] by Figure 24 Taking the structure and orientation shown as an example, when the same connector 400 includes two busbar connectors 403, the insulating side plate 800 corresponding to the connector 400 is also provided with two side plate grooves 801, so that each busbar connector 403 can be fitted into the corresponding side plate groove 801, further ensuring the stability of the relative position of the insulating side plate 800 with the main body 301 and the connector 400.

[0212] like Figure 17 and Figure 23In some embodiments, the explosion-proof valve 900 is approximately flush with the outer surface of the cover plate 101. This requires the second insulating support 502 to form a protruding structure protruding towards the main body 301 at the position corresponding to the explosion-proof valve 900. However, this results in a significant height difference (along a third direction) between the protruding structure and the first connecting portion 401. If the tab 302 connected to the first connecting portion 401 extends to the end of the protruding structure, the tab 302 is prone to bending and stress concentration due to the height difference, which may lead to breakage and other problems, seriously affecting the structural reliability of the electrode assembly 300 and the safety performance of the battery cell.

[0213] To avoid the above problems, this embodiment provides battery cells with other structures.

[0214] like Figure 27 , Figure 27a , Figure 27b and Figure 28 In some embodiments, the battery cell includes: an electrode assembly 300, including a main body 301 and a first tab 3021 extending from the end face of the main body 301; a cover plate 101, insulatedly connected to a terminal post 200; the cover plate 101 includes a first surface 1011 and a second surface 1012 disposed opposite to each other, the second surface 1012 facing the electrode assembly 300; the cover plate 101 is provided with an explosion-proof mounting hole 1013 penetrating the first surface 1011 and the second surface 1012; and an explosion-proof valve 900, including an explosion-proof base 901 and a pressure relief plate 902, the explosion-proof base 901 being connected to the cover plate 101 and protruding from the first surface 1011, the explosion-proof base 901 having a first air passage 903 communicating with the explosion-proof mounting hole 1013, and the pressure relief plate 902 blocking the first air passage 902. 3. An opening away from the cover plate 101; when the pressure relief plate 902 is subjected to pressure greater than a preset value, the pressure relief plate 902 ruptures and forms a pressure relief port; the connector 400 includes a first connecting portion 401 electrically connected to the pole post 200, the first connecting portion 401 including a third surface 4015 facing the main body 301, and a first electrode ear 3021 electrically connected to the third surface 4015; the second insulating bracket 502 includes a bracket body 5021 connected to the second surface 1012, the bracket body 5021 at least covers the explosion-proof mounting hole 1013 and forms a main body through hole 50211 communicating with the explosion-proof mounting hole 1013; along the third direction, the bracket body 5021 does not extend beyond the third surface 4015 towards the main body 301; the third direction is the thickness direction of the cover plate 101.

[0215] For example, the surface of the pressure relief plate 902 is provided with grooves, the depth of which is 40% to 60% of the thickness of the pressure relief plate 902, and the shape of the grooves is annular or waist-shaped (or fork-shaped). The grooves are the weak areas of the pressure relief plate 902. When the internal pressure of the battery cell reaches 0.8 MPa-1.2 MPa, the pressure relief plate 902 breaks along the grooves, forming a pressure relief port. The gas inside the battery cell can flow out through the pressure relief port to achieve pressure relief.

[0216] For example, the end of the explosion-proof base 901 away from the cover plate 101 may be provided with a stepped structure, and the pressure relief plate 902 is connected to the stepped structure to ensure that the pressure relief plate 902 and the explosion-proof base 901 are reliably connected and to improve the structural stability of the explosion-proof valve 900.

[0217] In this embodiment, the first tab 3021 of the electrode assembly 300 is electrically connected to the third surface 4015. Since the support body 5021 does not extend beyond the third surface 4015 towards the body 301, even if the tab 302 extends along the first direction towards the portion of the support body 5021 corresponding to the explosion-proof valve 900, it can remain flat and will not be squeezed by the support body 5021, effectively reducing the risk of tearing of the tab 302. Because the explosion-proof base 901 protrudes from the first surface 1011, the protrusion height of the support body 5021 relative to the second surface 1012 is also reduced, thereby releasing space inside the battery cell. The tab 302 can extend into this space to increase its width and area, thereby improving the current carrying capacity and heat dissipation capacity of the battery cell.

[0218] In this embodiment, the explosion-proof base 901 of the explosion-proof valve 900 is designed to protrude from the first surface 1011 of the cover plate 101. This reduces the protrusion height of the portion of the support body 5021 of the second insulating support 502 corresponding to the explosion-proof valve 900 towards the electrode assembly 300, thus freeing up more space within the battery cell. Since the entire support body 5021 is located on the side of the third surface 4015 closest to the cover plate 101, even if the tab 302 connected to the third surface 4015 extends into the aforementioned space, it will not be squeezed by the support body 5021. This increases the width of the tab 302, improving the current carrying capacity and heat dissipation capacity of the battery cell and enhancing its safety performance. It also reduces the risk of the tab 302 tearing under pressure, ensuring a stable and reliable electrical connection between the tab 302, the connector 400, and the terminal 200, thus guaranteeing the power performance of the battery cell.

[0219] like Figure 27a and Figure 27c In some embodiments, at least one of the cover plate 101 and the pressure relief plate 902 is integrally formed and connected to the explosion-proof substrate 901.

[0220] exist Figure 27a In the structure shown, the explosion-proof substrate 901 and the cover plate 101 are integrally formed and connected, and the pressure relief plate 902 can be welded and fixed to the explosion-proof substrate 901. The manufacturing process of the explosion-proof valve 900 in this structure is relatively simple, which is beneficial to improving the assembly efficiency of battery cells.

[0221] exist Figure 27c In the structure shown, the explosion-proof substrate 901 and the pressure relief plate 902 are integrally formed and connected, and the explosion-proof substrate 901 is welded and fixed to the cover plate 101. Since the welding position of the explosion-proof substrate 901 and the cover plate 101 is far away from the pressure relief plate 902, there is a significant safety distance, which can effectively avoid the heat generated by welding from adversely affecting the scoring position of the pressure relief plate 902, and can effectively improve the yield of the explosion-proof valve 900.

[0222] like Figure 27a , Figure 27c and Figure 28 In some embodiments, the first connecting portion 401 is projected along a third direction into the second insulating bracket 502 within the bracket body 5021. The bracket body 5021 and the second surface 1012 are spaced apart along a third direction to define the second air passage 1000. The area of ​​the bracket body 5021 corresponding to the first connecting portion 401 is also provided with a main body through hole 50211, which is connected to the explosion-proof mounting hole 1013 through the second air passage 1000.

[0223] In this embodiment, the main through holes 50211 are evenly arrayed on the support body 5021, and are not only located in the area corresponding to the explosion-proof valve 900, but also in the area corresponding to the first connecting part 401. When a battery cell experiences thermal runaway, the high-temperature gas generated inside it can enter the second air passage 1000 through the main through holes 50211 at various locations, and then converge towards the explosion-proof mounting hole 1013 and the first air passage 903 through the second air passage 1000, and finally be discharged through the pressure relief port of the explosion-proof valve 900. Because there are a large number of main through holes 50211 and their positions are relatively dispersed, the gas inside the battery can enter the second air passage 1000 in a timely and rapid manner through the main through holes 50211, which helps to improve the pressure relief efficiency of the battery cell and improve safety performance.

[0224] like Figure 27a and Figure 27c In some embodiments, along a third direction, the explosion-proof valve 900 protrudes from the first surface 1011 by an dimension of H1, and the pole post 200 protrudes from the first surface 1011 by an dimension of H2, where H2 ≥ H1 > 0 mm.

[0225] In this embodiment, by strictly limiting the height difference between the terminal post 200 and the explosion-proof valve 900 protruding from the first surface 1011, the spatial layout outside the cover plate 101 of the battery cell can be made more reasonable. When the terminal post 200 is electrically connected to an external circuit (e.g., a busbar), mechanical interference between the explosion-proof valve 900 and the external circuit can be avoided, ensuring a high connection quality between the terminal post 200 and the external circuit.

[0226] Meanwhile, by using the larger protruding pole post 200 as the design benchmark for the protruding size of the explosion-proof valve 900, as long as H1≤H2 is guaranteed, the explosion-proof valve 900 can avoid mechanical collision with the pole post 200 or other external components during battery cell assembly, handling or module integration, thereby improving the structural reliability and assembly convenience of the explosion-proof valve 900.

[0227] like Figure 27a and Figure 27c In some embodiments, along a third direction, the size of the first connecting part 401 is H, the size of the pole post 200 protruding from the second surface 1012 is H3, the maximum distance between the surface of the bracket body 5021 away from the cover plate 101 and the second surface 1012 is H4, and the absolute value of the difference between H3 and H4 is greater than or equal to 0 and less than or equal to H.

[0228] This embodiment specifically defines the relationship between H, H3, and H4, ensuring that the main body 5021 of the support does not protrude beyond the third surface 4015 of the first connecting part 401, thus providing ample space for the width design of the tab 302. When the width of the tab 302 is designed to be larger, the surface area of ​​the tab 302 is also correspondingly larger, which is beneficial to improving the current carrying capacity and heat dissipation capacity of the battery cell.

[0229] The performance of the battery cell in this embodiment can be further illustrated by the following experimental data.

[0230] Example: The battery cell is blade-shaped, 500mm long, 173mm wide, and 54mm thick. Its internal electrode assembly 300 has positive tabs 302a and negative tabs 302b extending from opposite ends of the main body 301. The positive tabs 302a at both ends are electrically connected to the terminal post 200 via connectors 400 as described in the various embodiments. Both the positive tabs 302a and the connectors 400 are made of aluminum. The negative tabs 302b at both ends are electrically connected to the terminal post 200 via connectors 400 as described in the various embodiments. Both the negative tabs 302b and the connectors 400 are made of copper. The active material of the positive electrode sheet of the electrode assembly 300 includes lithium iron phosphate, and the electrode assembly 300 has a wound structure.

[0231] When the tab 302 is unfolded, its base width is 70mm and its height is 30mm. The connector 400, which is electrically connected to the positive tab 302a, has a thickness of 1mm. The connector 400, which is electrically connected to the negative tab 302b, has a thickness of 0.8mm. The second insulating support 502 does not protrude from the third surface 4015 of the first connecting part 401.

[0232] The electrode assembly 300 and the connector 400 are covered with an insulating film 700. The connector 400 is ultrasonically welded to the tab 302 and laser-welded to the post 200.

[0233] Among them, H1 is 2.5mm, H2 is 3.2mm, H4 is 2mm, and H3 is 1mm.

[0234] Comparative example: The only difference between the comparative example and the above embodiment is that when the tab 302 is unfolded, its bottom width is 62mm, H1 is 0mm, H4 is 6mm, H3 is 1mm, and the second insulating bracket 502 protrudes from the third surface 4015 of the first connecting part 401.

[0235] Two cells from each of the two examples (Example 3 and Comparative Example 4) were selected to form Example 3, Example 4, Comparative Example 3 and Comparative Example 4. The following performance tests were performed on the four cells, and the positive electrode temperature of the individual cells was collected.

[0236] I. Standard volume at 25±2℃: 1) Let it stand at 25℃ for 3 hours; 2) Charge at 1C constant current to 3.65V, then switch to constant voltage charging, cut-off current 0.05C, and let stand for 30 minutes; 3) Discharge at a constant current of 1C to 2.5V, then let stand for 30 minutes; 4) Repeat steps 2-3 three times. The average discharge capacity of the three cycles is denoted as C0.

[0237] II. Rate Discharge Test (25±2℃): 1) Let stand for 30 minutes, charge at 1C constant current to 3.65V, switch to constant voltage charging, cut off current 0.05C, let stand for 30 minutes; discharge at 1C constant current to 2.5V, let stand for 30 minutes; 2) Charge at 1C constant current to 3.65V, then switch to constant voltage charging, with a cutoff current of 0.05C, and let stand for 60 minutes; 3) Discharge at a constant current of 1 / 3C to 2.5V and let stand for 60 minutes; repeat step 2 with only the discharge rate changing, and perform discharge at 0.5C / 1C / 2C / 3C rates respectively.

[0238] III. Rate Charging Test (25±2℃): 1) Let stand for 30 minutes, charge at 1C constant current to 3.65V, switch to constant voltage charging, cut off current 0.05C, let stand for 30 minutes; discharge at 1C constant current to 2.5V, let stand for 30 minutes; 2) Charge at 1 / 3C constant current to 3.65V, then switch to constant voltage charging, with a cutoff current of 0.05C, and let stand for 60 minutes; discharge at 1C constant current to 2.5V, and let stand for 60 minutes. 3) Repeat step 2 with only the charging rate changing, performing charging at 0.5C / 1C / 2C / 3C rates respectively.

[0239] The test data obtained from the above performance tests are shown in Table 2.

[0240] Table 2 Performance test data for Examples 3, 4, Comparative Examples 3 and 4

[0241] Based on the temperature rise data collected during the above test, the internal resistance was calculated, and the result was obtained. Figure 29 as well as Figure 30 The graph shows a comparison of temperature rise during charging and discharging.

[0242] Tests show that Examples 3 and 4, employing a widened tab 302 bottom width design, reduce 3C charging temperature rise by approximately 28%, 3C discharging temperature rise by 33%, and DCIR by 45%. As demonstrated by Examples 3, 4, Comparative Examples 3 and 4, the battery cells in these examples exhibit good rate performance, further broaden the overcurrent capability of the battery cells, and improve the thermal safety performance of the battery cells.

[0243] like Figure 27a and Figure 27c In some embodiments, the cover plate 101 is provided with a liquid injection through hole 1014, the second insulating support 502 is formed with a hollow structure to avoid the liquid injection through hole 1014, and the cover plate 101 is connected with a hole seal 1100 to block the liquid injection through hole 1014; along the third direction, the hole seal 1100 does not protrude from the surface of the second insulating support 502 away from the cover plate 101 towards the body 301.

[0244] It should be noted that electrolyte can be introduced into the battery cell through the injection hole 1014.

[0245] For example, the hole seal 1100 can be a ball pin.

[0246] Since the hole seal 1100 does not protrude from the surface of the second insulating support 502 away from the cover plate 101, the hole seal 1100 will not occupy additional space in the receiving cavity 103 and will not squeeze the tab 302. This can further amplify the above-mentioned structural advantages of the battery cell in this embodiment and help improve the space utilization of the receiving cavity 103.

[0247] like Figure 26 In some embodiments, the support body 5021 has a plurality of main body through holes 50211, the total opening area of ​​all main body through holes 50211 is Ah, the opening area of ​​the pressure relief port is Av, and Ah ≥ 1.2 × Av.

[0248] This embodiment limits the total opening area of ​​all the main through holes 50211 on the second insulating bracket 502, and performs a quantitative design of the pressure relief channel of the battery cell from a fluid dynamics perspective. This ensures that the flow capacity of the pressure relief channel inside the battery cell matches the release capacity of the explosion-proof valve 900, avoiding pressure relief bottlenecks. When thermal runaway occurs in the battery cell, it ensures that the high-temperature and high-pressure gas inside the battery cell can flow quickly and smoothly through the main through holes 50211 to the explosion-proof valve 900, and then be discharged through the pressure relief port of the explosion-proof valve 900. This effectively avoids problems such as the expansion or even rupture of the outer shell 100 caused by gas retention inside the battery cell, and helps to improve the pressure relief efficiency and reliability of the battery cell. At the same time, it can realize airflow guidance of the battery cell under normal operating conditions, improving the heat dissipation performance of the battery cell.

[0249] like Figure 27 , Figure 27b , Figure 31 and Figure 32 In some embodiments, the electrode assembly 300 further includes a second tab 3022, which extends from the end face of the main body 301 away from the terminal post 200 and has the same polarity as the first tab 3021; ​​the connector 400 further includes a second connecting portion 402 and a busbar connecting portion 403, the second connecting portion 402 being disposed on the side of the main body 301 away from the terminal post 200 and electrically connected to the second tab 3022, and the second connecting portion 402 being electrically connected to the first connecting portion 401 through the busbar connecting portion 403; the battery cell further includes a housing 102 and an insulating film 700, the housing... 102 has a housing opening 1021, and a cover plate 101 is connected to the housing opening 1021 to form a receiving cavity 103 inside the housing 102; a connector 400, an electrode assembly 300 and an insulating film 700 are disposed in the receiving cavity 103, and the insulating film 700 covers the connector 400 and the electrode assembly 300; the insulating film 700 is connected to an insulating pad 1200, the insulating pad 1200 is located between the insulating film 700 and the second connector 402, and the insulating pad 1200 and the second connector 402 at least partially overlap in the orthographic projection of the insulating film 700 along a third direction.

[0250] For example, the insulating pad 1200 can be made of battery-grade, low-emission, high-purity silicone foam to avoid reaction with electrolytes and contamination of electrode assembly 300.

[0251] To prevent the second connecting part 402 from directly contacting the insulating film 700 (and also to prevent the weld marks formed during welding of the second connecting part 402 to the second tab 3022 from directly contacting the insulating film 700), thus avoiding damage and failure of the insulating film 700 and subsequent overlap between the connector 400 and the housing 102, this embodiment provides an insulating pad 1200 between the second connecting part 402 and the insulating film 700. The insulating pad 1200 separates the second connecting part 402 from the insulating film 700, effectively preventing direct contact and ensuring the structural stability of the insulating film 700. This ensures mutual insulation between the electrode assembly 300, the connector 400, and the housing 100, reducing the risk of internal short circuits in the battery cell and further improving the safety performance of the battery cell.

[0252] In some embodiments, the Shore A hardness of the insulating pad 1200 is 30 to 60.

[0253] If the hardness of the insulating pad 1200 is too small, it will easily collapse under stress and will not be able to reliably support the second connection part 402; if the hardness of the insulating pad 1200 is too large, it will easily cause damage to the connector 400 and the tab 302.

[0254] To avoid the aforementioned problems, this embodiment designs the Shore A hardness of the insulating pad 1200 to be 30 to 60. This ensures that the insulating pad 1200 provides stable and reliable support for the second connecting part 402, guaranteeing the stability of the second connecting part 402 and the tab 302 within the receiving cavity 103. It also prevents the insulating pad 1200 from damaging the connecting part 400 and the tab 302, ensuring the structural stability and connection reliability of the connecting part 400 and the tab 302, thereby helping to improve the power performance and safety performance of the battery cell.

[0255] like Figure 31 In some embodiments, along the second direction, the size of the receiving cavity 103 is W1, the size of the insulating pad 1200 is W2, the thickness of the body 301 is D, and W1-0.4mm≥W2≥D; the second direction is the thickness direction of the electrode assembly 300.

[0256] W2 is slightly smaller than W1, which ensures that the insulating film 700 can be smoothly installed into the receiving cavity 103; W2 is greater than or equal to D, which ensures that the insulating pad 1200 can provide relatively comprehensive insulation, isolation and support for the tab 302 and the second connecting part 402.

[0257] like Figure 27 , Figure 27a , Figure 27b , Figure 27c and Figure 32In some embodiments, the insulating film 700 is connected to a side guard plate 1300, which is disposed on the side of the insulating film 700 away from the busbar connection portion 403. Along the thickness direction of the insulating film 700, the side guard plate 1300 and the busbar connection portion 403 at least partially overlap in their orthographic projections on the insulating film 700.

[0258] It should be noted that in some embodiments, the side guard plate 1300 may also be disposed between the insulating film 700 and the bus connection portion 403.

[0259] For example, the side guard plate 1300 may be provided with positioning holes to ensure that the relative positions of the insulating film 700, the electrode assembly 300 and the cover plate 101 meet the design requirements when the insulating film 700 is assembled.

[0260] By setting the side guard plate 1300, the busbar connection part 403 can be insulated from the side wall of the housing 102, which effectively reduces the risk of the connector 400 and the housing 102 overlapping, avoids internal short circuit of the battery cell, and helps to improve the safety performance of the battery cell.

[0261] like Figure 27 and Figure 27b In some embodiments, the second connection portion 402 is fitted with a first insulating bracket 501, which is located between the second tab 3022 and the bus connection portion 403; along a third direction, the orthographic projection of the insulating pad 1200 on the second connection portion 402 at least covers the exposed portion of the second connection portion 402 relative to the first insulating bracket 501 500.

[0262] In this embodiment, a portion of the second connecting part 402 can be covered by the first insulating bracket 501500, and another portion can be covered by the insulating pad 1200. Therefore, a relatively comprehensive insulation isolation is formed between the second connecting part 402 and the housing 102, which fundamentally avoids the second connecting part 402 from overlapping with the housing 102, prevents the battery cell from having an internal short circuit, and helps to improve the safety performance of the battery cell.

[0263] like Figure 27b In some embodiments, along a third direction, the orthographic projections of the insulating pad 1200 and the second tab 3022 on the second connection portion 402 at least partially overlap; the second connection portion 402 includes a fourth surface 4023 away from the cover plate 101, and along a third direction, the first insulating support 501 protrudes from the fourth surface 4023 by a dimension d2 in the direction away from the cover plate 101, and the insulating pad 1200 has a dimension d1, where d2 = d1.

[0264] by Figure 27bTaking the structure and orientation shown as an example, designing d1 and d2 to be the same can avoid the height difference between the insulating pad 1200 and the second connection part 402 below the second connection part 402, avoid stress concentration in the second connection part 402, reduce the risk of deformation or even tearing of the second connection part 402, and ensure that the electrode assembly 300 and the connector 400 can be stably and reliably connected.

[0265] like Figure 27b In some embodiments, along a third direction, the orthographic projections of the insulating pad 1200 and the second tab 3022 on the second connection 402 at least partially overlap; along a first direction, the size of the insulating pad 1200 is L1, the size of the second connection 402 is L2, the size of the first insulating support 501500 is L3, and L1≥L2-L3; the first direction is the width direction of the second tab 3022.

[0266] By designing L1 to be greater than or equal to L2-L3, it can be ensured that the insulating pad 1200 can fully cover the exposed part of the second connection 402, and a relatively comprehensive insulation isolation is formed between the second connection 402 and the housing 102. This fundamentally avoids the second connection 402 from overlapping with the housing 102, prevents the battery cell from having an internal short circuit, and helps to improve the safety performance of the battery cell.

[0267] Based on the same inventive concept and in conjunction with the description of the battery cells in the above embodiments, this embodiment provides a battery cell assembly method. This method has the corresponding technical effects of the battery cells in the above embodiments, which will not be repeated here.

[0268] like Figure 33 In some embodiments, the battery cell assembly method includes: Step S101: Provide a connector and an electrode assembly; the connector is a sheet-like structure, including a first connecting part, a busbar connecting part and a second connecting part, the second connecting part being electrically connected to the first connecting part through the busbar connecting part; the electrode assembly includes a main body, and a first electrode tab and a second electrode tab with the same polarity are respectively led out from opposite ends of the main body.

[0269] The structure of the connector 400 is similar to that of the aforementioned integrally formed connector 400, and the structure of the electrode assembly 300 is also similar to that of the aforementioned electrode assembly 300, so it will not be described again here.

[0270] In this embodiment, the thickness of the connector 400 connected to the positive electrode tab 302a can be 1 mm or 1.5 mm, and the thickness of the connector 400 connected to the negative electrode tab 302b can be 0.8 mm or 1.2 mm.

[0271] Step S102: Electrically connect the first electrode tab to the first connecting part, and electrically connect the second electrode tab to the second connecting part.

[0272] For example, the first electrode 3021 can be electrically connected to the first connecting part 401 via ultrasonic welding; similarly, the second electrode 3022 can be electrically connected to the second connecting part 402 via ultrasonic welding. Welding parameters can be: welding energy 450±50J, welding pressure 2~4 bar, welding amplitude 80±10%, and welding head / weld seat gap 0.2±0.2mm. After welding, the weld mark is covered with protective adhesive.

[0273] Step S103: Provide a cover plate, the cover plate being insulatedly connected to an electrode post.

[0274] The cover plate 101 in this embodiment has a similar structure to the cover plate 101 described above, and will not be repeated here.

[0275] Step S104: Place the second connecting part along the second direction on at least one side of the cover plate, and electrically connect the first connecting part to the pole post; the second direction is the width direction of the cover plate.

[0276] For example, the first connecting part 401 can be electrically connected to the pole post 200 by laser welding. The welding parameters can be: positive pole side (connector 400 thickness is 1.5mm): laser power 54%±5%, welding speed 300±50mm / s; negative pole side (connector 400 thickness is 1.2mm): laser power 96%±3%, welding speed 250±50mm / s. Alternatively, the welding parameters can be: positive pole side (connector 400 thickness is 1mm): laser power 45%±5%, welding speed 300±50mm / s; negative pole side (connector 400 thickness is 0.8mm): laser power 87%±5%, welding speed 250±50mm / s.

[0277] like Figure 4 At this time, the connector 400 is in the first state. The first connecting part 401 of the connector 400 is placed above the cover plate 101 and the pole post 200. The orthographic projection of the second region 4014 of the first connecting part 401 on the cover plate 101 covers the pole post 200. Then, the first connecting part 401 and the pole post 200 can be electrically connected.

[0278] When the first connecting part 401 and the pole post 200 are electrically connected by welding, protective adhesive is applied at the location where the weld mark is formed, and U-shaped adhesive is applied at the preset position to achieve insulation protection and structural reinforcement of the welding area, reducing the risk of weld mark corrosion and internal short circuit.

[0279] Step S105: Flip the busbar connection to move the second connection and the main body to the side of the first connection away from the cover plate.

[0280] like Figure 5 At this time, the main body 301 moves from a flat position to a vertical position, and the first pole ear 3021 bends as the main body 301 flips.

[0281] Step S106: Flip the second connecting part so that the second connecting part is parallel to the first connecting part.

[0282] The second tab 3022 bends as the second connecting part 402 flips.

[0283] The battery cell assembly method provided in this embodiment eliminates the need for multiple separate parts to be aligned, assembled, and corrected step-by-step during battery cell assembly, as the connector 400 is a one-piece molded structure. This ensures a single assembly benchmark and rapid, convenient positioning. Combined with a standardized assembly method, it significantly reduces redundant operations such as on-site tooling switching, manual alignment and re-inspection, and step-by-step auxiliary fixing. It simplifies the entire on-site mass production assembly process, from electrical connection and bending to connector pre-assembly, lowering the difficulty of on-site process control and reducing the barrier to manual operation. Simultaneously, it effectively shortens the overall assembly cycle time of the battery cell and reduces assembly station time.

[0284] Meanwhile, the standardized assembly method can ensure the electrical connection quality of the electrode assembly 300, connector 400 and terminal post 200, which helps to improve the power performance and safety performance of the battery cell.

[0285] In some embodiments, before step S105 and after step S104, the bus connection portion is located outside the body along a first direction, where the first direction is the width direction of the first electrode tab, and the method includes: Step S107: Flip the busbar connection portion toward the main body so that the busbar connection portion is perpendicular to the first connection portion and the second connection portion.

[0286] For example, the flip angle of the bus connection 403 can be 85° to 100°, such as 85°, 90°, 95° or 100°.

[0287] For example, the flip angle tolerance is controlled within ±1°.

[0288] like Figure 34 The bus connector 403 is bent at an angle of 90° so that the first connector 401 and the bus connector 403 form an L-shaped structure when projected along the second direction. After the bus connector 403 is flipped, its larger surface area is close to the side wall of the main body 301, which is suitable for the assembly requirements of the subsequent step S105.

[0289] In some embodiments, the connector further includes a first bend, and the bus connection is electrically connected to the first connection via the first bend; Step S105 includes: The connection between the first bent portion and the first connecting portion is bent to flip the busbar connection portion.

[0290] For example, after step S105 is completed, the gap between the connector 400 and the adjacent end face of the main body 301 is less than or equal to 1 mm, which can significantly reduce the redundant space between the main body 301 and the outer shell 100 along a third direction.

[0291] After bending the connection between the first bending portion 404 and the first connecting portion 401, the end face of the main body 301 can be moved to a position close to the first connecting portion 401, ensuring that the first tab 3021 and the first connecting portion 401 fit tightly together, which helps to improve the stability of the current carrying capacity of the battery cell.

[0292] In some embodiments, the connector further includes a second bend, and the bus connection is electrically connected to the second connection via the second bend; Step S106 includes: The connection between the second bent portion and the second connecting portion is bent to flip the second connecting portion.

[0293] For example, after step S106 is completed, the gap between the connector 400 and the adjacent end face of the main body 301 is less than or equal to 1 mm, which can significantly reduce the redundant space between the main body 301 and the outer shell 100 along a third direction.

[0294] After bending the connection between the second bending portion 405 and the second connecting portion 402, the end face of the main body 301 can be moved to a position close to the second connecting portion 402, ensuring that the second tab 3022 and the second connecting portion 402 fit tightly together, which helps to improve the stability of the current carrying capacity of the battery cell.

[0295] In some embodiments, step S107 includes: The connection between the first bent portion and the busbar connection portion, and the connection between the second bent portion and the busbar connection portion are bent to flip the busbar connection portion.

[0296] The connection between the first bending part 404 and the busbar connection part 403, and the connection between the second bending part 405 and the busbar connection part 403, can ensure that the busbar connection part 403 fits more tightly with the side wall of the main body 301, which helps to improve the energy density of the battery cell.

[0297] In some embodiments, the second connection portion includes a first sub-portion and a second sub-portion, the first sub-portion and the second sub-portion are each connected to the first connection portion through the bus connection portion, and the electrode assembly includes a first body and a second body; Step S102 includes: The first electrode led out from the first main body is electrically connected to the first connecting part, and the second electrode led out from the first main body is electrically connected to the first sub-part; The first electrode led out from the second main body is electrically connected to the first connecting part, and the second electrode led out from the second main body is electrically connected to the second sub-part.

[0298] In this embodiment, the first body 301a and the second body 301b are respectively connected to the connector 400 in a stable electrical manner. It should be noted that the electrical connection method between the tabs 302 (including the first tab 3021 and the second tab 3022) led out from the first body 301a and the connector 400 is similar to the electrical connection method between the tabs 302 led out from the second body 301b and the connector 400.

[0299] In some embodiments, step S104 includes: The first sub-part and the second sub-part are placed on opposite sides of the cover plate along the second direction.

[0300] When the connector 400 is in the first state, positioning the cover plate 101 and the first connecting portion 401, the first sub-part 4021 and the second sub-part 4022 are located on opposite sides of the cover plate 101 and the first connecting portion 401, respectively. The first main body 301a and the second main body 301b are also located on opposite sides of the cover plate 101 and the first connecting portion 401, and will not obstruct the electrical connection between the first connecting portion 401 and the electrode 302, thus facilitating operation.

[0301] In some embodiments, step S105 includes: Flip the junction connection so that the first body and the second body come together on the side of the first connection away from the cover plate.

[0302] After the connector 400 and the pole post 200 are electrically connected, the first body 301a and the second body 301b are brought together above the first connecting part 401 to complete the core assembly. Adhesive tape is applied to the first body 301a and the second body 301b after the core assembly is completed. The adhesive tape extends in a U-shape from the side wall of the first body 301a with the larger surface area to the side wall of the second body 301b with the larger surface area.

[0303] Taking the portion of the tape adhered to the first body 301a as an example, the portion of the tape covering the sidewall with a larger surface area of ​​the first body 301a can have a length greater than or equal to 10 mm, the distance from the edge of the sidewall along its width direction can be greater than or equal to 30 mm, the width of the tape can be 30 mm ± 0.5 mm, the overall length of a single strip of tape can be 90 mm ± 2 mm, and the size of the tape can be 30 mmW. 88mmL 30μmT.

[0304] In some embodiments, step S106 includes: The first sub-part and the second sub-part are flipped in opposite directions so that the first sub-part and the second sub-part are joined together to form the second connecting part.

[0305] The first sub-part 4021 and the second sub-part 4022 are flipped about 90° towards each other so that they are roughly parallel to the first connecting part 401, thereby forming the second connecting part 402.

[0306] It should be noted that the first sub-part 4021 and the second sub-part 4022 in this embodiment are assembled, which does not mean that the first sub-part 4021 and the second sub-part 4022 are connected into a whole. Rather, it means that the two are close to each other after being flipped. They can be in direct contact or not, and this is not limited here.

[0307] In some embodiments, the aforementioned battery cell can be formed at least by the battery cell assembly method described in the above embodiments.

[0308] Based on the same inventive concept and in conjunction with the description of the battery cells in the above embodiments, this embodiment provides a battery pack that has the corresponding technical effects of the battery cells in the above embodiments, which will not be repeated here.

[0309] This embodiment provides a battery pack, including battery cells as described in the above embodiments.

[0310] Specifically, the battery pack includes at least one battery cell according to any of the above embodiments and a housing, the housing being used to house at least one battery cell.

[0311] The enclosure may include an upper enclosure and a lower enclosure, with the upper enclosure covering the lower enclosure to form a closed space for accommodating individual battery cells. The enclosure may contain one, two, or more individual battery cells, which may be arranged in any manner within the enclosure.

[0312] A single battery cell or battery pack can be used as a power source for an electrical device or as an energy storage unit for that device. Electrical devices can include, but are not limited to, mobile devices (such as mobile phones, laptops, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.

[0313] The battery pack has the technical effects of any of the above embodiments, and is not limited thereto.

[0314] It should be noted that some embodiments of the present invention have been described above. Other embodiments are within the scope of the appended claims.

[0315] The various embodiments in this invention are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0316] The description of this invention is given for illustrative and descriptive purposes only and is not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of the invention and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.

[0317] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention (including the claims) is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of the embodiments of the invention as described above, which are not provided in the details for the sake of brevity.

[0318] Although the invention has been described in conjunction with specific embodiments thereof, many substitutions, modifications and variations of these embodiments will be apparent to those skilled in the art from the foregoing description.

[0319] The embodiments of this invention are intended to cover all such substitutions, modifications, and variations falling within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of this invention should be included within the protection scope of this invention.

Claims

1. A method for assembling a single battery cell, characterized in that, include: A connector and an electrode assembly are provided; the connector is a sheet-like structure, including a first connecting part, a busbar connecting part and a second connecting part, the second connecting part being electrically connected to the first connecting part through the busbar connecting part; the electrode assembly includes a main body, with a first electrode tab and a second electrode tab of the same polarity respectively led out from opposite ends of the main body; The first electrode tab is electrically connected to the first connecting part, and the second electrode tab is electrically connected to the second connecting part; A cover plate is provided, wherein the cover plate is insulatedly connected to an electrode post; The second connecting part is placed on at least one side of the cover plate along the second direction, and the first connecting part is electrically connected to the pole post; the second direction is the width direction of the cover plate; Flip the busbar connection so that the second connection and the main body move to the side of the first connection away from the cover plate; Flip the second connecting part so that it is parallel to the first connecting part.

2. The battery cell assembly method according to claim 1, characterized in that, Before flipping the busbar connection and after electrically connecting the first connection to the electrode post, the busbar connection is located outside the body along a first direction, the first direction being the width direction of the first electrode tab. The method includes: Flip the busbar connection portion toward the main body so that the busbar connection portion is perpendicular to the first connection portion and the second connection portion.

3. The battery cell assembly method according to claim 2, characterized in that, The connector further includes a first bend, and the busbar connection is electrically connected to the first connection through the first bend; The flipping of the bus connector includes: The connection between the first bent portion and the first connecting portion is bent to flip the busbar connection portion.

4. The battery cell assembly method according to claim 3, characterized in that, The connector further includes a second bend, and the bus connection is electrically connected to the second connection through the second bend; The flipping of the second connecting portion includes: The connection between the second bent portion and the second connecting portion is bent to flip the second connecting portion.

5. The battery cell assembly method according to claim 4, characterized in that, The step of flipping the bus connector towards the main body includes: The connection between the first bent portion and the busbar connection portion, and the connection between the second bent portion and the busbar connection portion are bent to flip the busbar connection portion.

6. The battery cell assembly method according to claim 1, characterized in that, The second connection portion includes a first sub-part and a second sub-part, and the first sub-part and the second sub-part are each connected to the first connection portion through the bus connection portion. The electrode assembly includes a first body and a second body. The step of electrically connecting the first electrode tab to the first connecting portion and the second electrode tab to the second connecting portion includes: The first electrode led out from the first main body is electrically connected to the first connecting part, and the second electrode led out from the first main body is electrically connected to the first sub-part; The first electrode led out from the second main body is electrically connected to the first connecting part, and the second electrode led out from the second main body is electrically connected to the second sub-part.

7. The battery cell assembly method according to claim 6, characterized in that, The step of placing the second connecting portion along the second direction on at least one side of the cover plate includes: The first sub-part and the second sub-part are placed on opposite sides of the cover plate along the second direction.

8. The battery cell assembly method according to claim 7, characterized in that, The step of flipping the manifold connection to move the second connection and the main body to the side of the first connection away from the cover plate includes: Flip the junction connection so that the first body and the second body are brought together on the side of the first connection away from the cover plate; The step of flipping the second connecting portion so that the second connecting portion is parallel to the first connecting portion includes: The first sub-part and the second sub-part are flipped in opposite directions so that the first sub-part and the second sub-part are joined together to form the second connecting part.

9. A single battery cell, characterized in that, The battery cell is formed using the battery cell assembly method as described in any one of claims 1 to 8.

10. A battery pack, characterized in that, Includes the battery cell as described in claim 9.

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