Battery cells and battery modules

Abstract

The present invention relates to a battery cell and a battery module, wherein the battery cell comprises an electrode assembly (1), comprising a main body (12) and a pole ear (11) extending from the end thereof; two terminals; and two current collecting components, respectively electrically connecting the pole ears (11) on both sides of the main body (12) with the terminals on the same side; the current collecting components comprise a guide plate (51) and a support plate (52), the guide plate (51) being located on one side of the main body (12) along the length direction and extending along the width direction, the guide plate (51) being provided with a reinforcement part for reducing the deformation of the guide plate (51) toward the side of the main body (12); the support plate (52) being connected to the end of the guide plate (51) along the width direction, the pole ear (11) being bent relative to the length direction and connected to the support plate (52). Such a battery cell can reduce the bending deformation of the guide plate toward the side of the main body of the electrode assembly, thereby improving the electrochemical performance of the battery cell.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and in particular to a battery unit and a battery module. Background Art

[0002] In recent years, rechargeable batteries have been widely used to provide power for high-power devices, such as electric vehicles, etc. Rechargeable batteries achieve a larger capacity or power by connecting a plurality of battery cells in series or in parallel.

[0003] The current battery cell is provided with an electrode assembly in the shell. The electrode assembly is formed by stacking and winding a positive electrode sheet, a separator and a negative electrode sheet. The positive electrode sheet and the negative electrode sheet each include a coated portion and an uncoated portion. The uncoated portion forms a pole ear. The pole ears on both sides of the electrode assembly are respectively connected to the positive and negative electrode posts on the top of the shell through a current collecting component.

[0004] In the related art known to the inventor, the current collecting components on both sides of the electrode assembly adopt a bent structure to improve the reliability of welding and fixing with the tabs by increasing their own structural strength, and the tabs are attached to the outer side of the bent structure and folded back together. In the actual use of such battery cells, it is found that the electrochemical performance and safety performance are poor. Summary of the invention

[0005] Embodiments of the present invention provide a battery cell and a battery module, which can improve the electrochemical performance of the battery.

[0006] According to one aspect of the present invention, there is provided a battery cell, comprising:

[0007] The electrode assembly comprises a main body and a tab extending from an end of the main body along a length direction;

[0008] Two terminals, located on top of the electrode assembly; and

[0009] Two current collecting components electrically connect the tabs on both sides of the main body to the terminals on the same side respectively;

[0010] Among them, the current collecting component includes a guide plate and a support plate. The guide plate is located on one side of the main body along the length direction and extends along the width direction. A reinforcement part is provided on the guide plate, which is configured to reduce the deformation of the guide plate toward the side of the main body; the support plate is connected to the end of the guide plate along the width direction, and the pole ear is bent relative to the length direction and connected to the support plate.

[0011] In some embodiments, the reinforcing portion includes ribs, and the ribs extend along the height direction or extend obliquely relative to the height direction.

[0012] In some embodiments, the reinforcement portion includes a plurality of ribs disposed at intervals, and each rib is disposed independently or staggered.

[0013] In some embodiments, a side of the rib close to the electrode assembly is recessed inwardly relative to the guide plate.

[0014] In some embodiments, a side of the reinforcing portion away from the electrode assembly protrudes outward relative to the guide plate.

[0015] In some embodiments, the support plate includes a connecting portion and a bending portion, the bending portion is connected to the guide plate and bent into an arc shape, the tab is connected to the connecting portion and folded back along the surface of the bending portion to a side of the guide plate away from the main body.

[0016] In some embodiments, the reinforcing portion includes ribs, the ribs include first ribs, the first ribs are covered by the connecting portion in the width direction, the first ribs have a first protrusion height relative to the guide plate, the bent portion has a third protrusion height relative to the guide plate, and the first protrusion height is less than or equal to the third protrusion height.

[0017] In some embodiments, two support plates are provided, and the two support plates are respectively connected to the two ends of the guide plate along the width direction and are bent relative to each other, and the connection parts of the two support plates are arranged at intervals along the width direction;

[0018] The ribs also include a second rib. The first rib is provided with two sections. The two sections of the first rib are covered by different connecting parts. The second rib is located between the two sections of the first rib and in the interval area between the two connecting parts.

[0019] In some embodiments, the second rib has a second protrusion height relative to the guide plate, and the second protrusion height is greater than or equal to the first protrusion height.

[0020] In some embodiments, the curved portion has at least one of a through slot and a groove extending along the height direction, the through slot is arranged in the middle area of ​​the curved portion along the height direction, and the groove is arranged on the inner side of the curved portion and located at least one place above and below the through slot.

[0021] In some embodiments, the reinforcement portion covers the support plate in the height direction.

[0022] In some embodiments, the battery cell further comprises a top cover plate and a lower insulating member, the terminal is disposed on the top cover plate, and the lower insulating member is disposed between the top cover plate and the electrode assembly;

[0023] The two current collecting members include a first current collecting member located at one side of the electrode assembly, the two terminals include a negative terminal, the first current collecting member connects the tab on the side with the negative terminal, and the reinforcement portion of the first current collecting member extends to the lower side of the lower insulator in the height direction.

[0024] In some embodiments, the two current collecting components include a second current collecting component located on one side of the electrode assembly, the two terminals include a positive terminal, the second current collecting component connects the electrode tab on its side to the positive terminal, and the second current collecting component also includes a heat dissipation portion, which is provided in the area where the guide plate is located above the support plate.

[0025] In some embodiments, the reinforcement portion of the second current collecting member extends to a lower side of the heat dissipation portion in the height direction.

[0026] In some embodiments, the current collecting member further includes a clamping portion, which is disposed at the bottom of the guide plate and protrudes as a whole toward a side away from the electrode assembly.

[0027] In some embodiments, along the length direction, the surface of the clamping portion away from the guide plate is not higher than the surface of the tab away from the guide plate after being folded back.

[0028] According to another aspect of the present invention, there is provided a battery module, comprising:

[0029] A plurality of battery cells of the above embodiments are arranged side by side along the width direction.

[0030] Based on the above technical solution, a battery cell of an embodiment of the present invention can increase the cross-sectional bending stiffness of the guide plate in a direction perpendicular to the height of the electrode assembly by setting a reinforcement portion on the guide plate of the current collecting component. In the process of bending and flattening the pole ear and the support plate, the bending deformation of the guide plate toward the side of the main body of the electrode assembly can be reduced, preventing the active materials coated on each pole piece in the electrode assembly from being affected, thereby improving the electrochemical performance and safety performance of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0032] Figure 1 A schematic structural diagram of an embodiment of a battery unit of the present invention;

[0033] Figure 2 A schematic diagram of the internal structure of a battery unit according to an embodiment of the present invention;

[0034] Figure 3 It is a structural schematic diagram of an embodiment of an electrode assembly in a battery cell of the present invention;

[0035] Figure 4 for Figure 1 an exploded view of the battery cell shown;

[0036] Figure 5A top view of an embodiment of a battery cell of the present invention;

[0037] Figure 6 for Figure 5 AA cross-sectional view of the battery cell shown;

[0038] Fig. 7A and Figure 7B They are Figure 6 Enlarged view of B and C in the figure;

[0039] Figure 8 It is a front view of the internal structure of the battery unit of the present invention;

[0040] Fig. 9 for Figure 8 Schematic diagram of the state where the section is made at the DD position and the tab is not folded back;

[0041] Fig.10 for Figure 8 The schematic diagram of the state after the section is made at the DD position and the tab is folded back;

[0042] Fig.11A and Fig. 11B They are Figure 8 The left view (corresponding to the positive terminal side) and the right view (corresponding to the negative terminal side) of the device;

[0043] Fig.12 A three-dimensional diagram of an embodiment of a first current collecting member (corresponding to a positive terminal) in a battery cell of the present invention;

[0044] Fig.13 for Fig.12 A side view of the first current collecting member shown;

[0045] Fig.14 for Fig.13 EE section enlarged view in;

[0046] Fig.15 A side view of an embodiment of a second current collecting member (corresponding to a negative terminal) in a battery cell of the present invention;

[0047] Fig.16 is a perspective view of another embodiment of a current collecting member in a battery cell of the present invention;

[0048] Fig.17 for Fig.16 A side view of the current collecting member shown;

[0049] Fig.18 for Fig.17 FF cross-sectional enlarged view.

[0050] Description of Reference Numerals

[0051] 1. Electrode assembly; 11. Tab; 12. Main body; 2. Top cover plate; 21. Exhaust member; 22. Liquid injection hole; 3. Negative terminal; 4. Positive terminal; 5. First current collecting member; 51. Guide plate; 511. Rib; 512. Clamping portion; 52. Support plate; 521. Connecting portion; 522. Bending portion; 523. Through groove; 524. Recess; 53. Adapter plate; 54. Heat dissipation portion; 6. Second current collecting member; 7. Lower insulating member; 8. Shell; 9. Insulating film. DETAILED DESCRIPTION

[0052] The present invention is described in detail below. In the following paragraphs, different aspects of the embodiments are defined in more detail. Each aspect so defined can be combined with any other aspect or aspects, unless explicitly stated not to be combined. In particular, any feature that is considered to be preferred or advantageous can be combined with one or more other features that are considered to be preferred or advantageous.

[0053] The terms "first", "second" and the like appearing in the present invention are only for the convenience of description to distinguish different components with the same name, and do not indicate a priority or primary and secondary relationship.

[0054] In addition, when an element is referred to as being "on" another element, the element may be directly on the other element, or may be indirectly on the other element with one or more intermediate elements interposed therebetween. In addition, when an element is referred to as being "connected to" another element, the element may be directly connected to the other element, or may be indirectly connected to the other element with one or more intermediate elements interposed therebetween. Hereinafter, the same reference numerals represent the same elements.

[0055] In order to clearly describe various directions in the following embodiments, for example Figure 1 The coordinate system in defines various directions of the battery cell, where the x direction represents the length direction of the electrode assembly; the y direction is perpendicular to the x direction in the horizontal plane, representing the width direction of the electrode assembly; the z direction is perpendicular to the plane formed by the x and y directions, representing the height direction of the electrode assembly. Based on this orientation definition, the descriptions of orientation or positional relationship indicated by "upper", "lower", "top", "bottom", "front", "back", "inside" and "outside" are used only for the convenience of describing the present invention, and do not indicate or imply that the device referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the scope of protection of the present invention.

[0056] After noticing that existing battery cells have poor electrochemical and safety performance, the inventors discovered that the active material coated on the pole pieces in the electrode assembly was peeling off and shedding powder. They speculated that the pole pieces might be subjected to external forces during the assembly process of the battery cells.

[0057] By analyzing the assembly process of the battery cell, reference Fig. 9 and Fig.10 In the process of bending the pole tabs 11 on both sides together with the support plate 52 of the current collecting member relatively inward, it is first necessary to apply force to the outer side of the pole tab 11 by a roller to gradually fold it inward. After it is roughly folded back to the position, the guide plate 51 of the current collecting member is placed upward away from the side of the electrode assembly main body 12, and then the pole tabs 11 on both sides are flattened by the flat plate structure, and the flat plate structure covers the corresponding areas of the two pole tabs 11. When pressure is applied to the pole tabs 11 on both sides by the flat plate structure, the current collecting member will produce a concave deformation toward the direction of the main body 12 and press against the main body 12, thereby transmitting the pressure to at least part of the pole piece in the main body 12, which is likely to cause the pole piece coated with active material to be subjected to mechanical force and peel off or powder, thereby affecting the electrochemical performance and safety performance of the battery unit.

[0058] To verify this analysis, the inventors used a micrometer to measure the deformation of the guide plate 51 after the tab 11 and the support plate 52 were folded back and flattened during assembly, and found that the guide plate 51 would deform more toward the main body 12 .

[0059] In order to reduce the deformation of the guide plate 51, an improved method is to provide clamping parts on both sides of the guide plate 51 located on the pole lug 11 along the height direction, and the clamping parts are convex outwardly relative to the guide plate 51 and concave inside. In the process of bending and flattening the pole lug, a tool is inserted into the concave part of the clamping part on the side facing the main body 12 to provide a supporting force. Although this method can reduce the deformation of the guide plate 51, this structure with support at both ends will still produce a large concave deformation in the middle area when bending the pole lug, and cannot substantially improve the deformation problem of the current collecting component. Moreover, inserting the tooling inside the clamping part requires high precision of the assembly equipment, which is actually difficult to assemble and has low assembly efficiency. Therefore, it is necessary to further improve the battery cell.

[0060] In order to enable those skilled in the art to clearly understand the improvements of the present invention, the overall structure of the battery unit is first described.

[0061] Figure 1 The schematic diagram of the structure of an embodiment of a battery cell of the present invention is shown. The battery cell may include an electrode assembly 1, a top cover plate 2, two terminals and two current collecting members.

[0062] The electrode assembly 1 includes a main body 12 and a tab 11 extending from the end of the main body 12 along the length direction. The main body 12 is the coated part of the electrode, including a first electrode and a second electrode with opposite polarities, for example, the first electrode is a negative electrode, and the second electrode is a positive electrode. The tab 11 is an uncoated part, which can extend outward from both ends of the main body 12 along the length direction.

[0063] like Figure 2 The schematic diagram of the internal structure of the battery cell shown in the figure shows that the top cover plate 2 is arranged on the top of the electrode assembly 1, and a lower insulating member 7 is arranged between the top cover plate 2 and the electrode assembly 1. For example, the lower insulating member 7 can be a plate-shaped structure adapted to the top cover plate 2, and can be made of plastic material. The top cover plate 2 is provided with a venting member 21 and a liquid injection hole 22. The venting member 21 is used to release the gas in the battery cell to play a safety role. The liquid injection hole 22 is used to inject electrolyte into the battery cell and seal it with a seal. Two terminals are arranged at both ends of the top cover plate 2 along the length direction, including a negative terminal 3 connected to the negative electrode and a positive terminal 4 connected to the positive electrode.

[0064] refer to Fig. 9 and Fig.10 , the two current collecting components electrically connect the pole lugs 11 on both sides of the main body 12 along the length direction to the terminals on the same side. The current collecting component may include a guide plate 51 and a support plate 52. The guide plate 51 is located on one side of the main body 12 along the length direction and extends along the width direction. The support plate 52 is connected to the end of the guide plate 51 along the width direction. The pole lug 11 is bent relative to the length direction and connected to the support plate 52. For example, the pole lug 11 and the support plate 52 can be connected by welding. Fig.10 As shown, the pole ear 11 is attached to the outer side of the support plate 52 and bent inwardly toward the guide plate 51; or the pole ear 11 is attached to the outer side of the support plate 52 and bent outwardly, and after bending, the guide plate 51 and the support plate 52 of the current collecting component can be a flat plate structure.

[0065] When the battery cell is used independently, a shell 8 connected to the cover plate is further provided outside the electrode assembly 1, and the shell 8 is filled with electrolyte. When multiple battery cells are formed into a battery module, the battery module includes a battery frame and multiple battery cells, each of which is arranged in the battery frame and arranged side by side along the width direction, and can be connected in parallel and / or in series. Each battery cell can be provided with a shell 8 separately, or the shell 8 can be omitted.

[0066] The electrode assembly 1 in the battery cell can be set as a single one, which is suitable for the case where the thickness of each electrode is small after being stacked. When the thickness of each electrode is large after being stacked, two or more independently wound electrode assemblies 1 can also be set in the battery cell, and the pole ears 11 corresponding to each electrode assembly 1 are respectively led out from both sides of the main body 12 along the width direction. When the winding thickness of the electrode assembly 1 is large, the arc size at the bottom is large, which will lead to low space utilization of the electrode assembly 1 on the outside of the arc on both sides of the bottom. Splitting it into multiple electrode assemblies can reduce the arc size, make full use of the bottom space of the battery cell, reduce space waste, and increase the energy density of the main body. Moreover, the total thickness of the pole ear 11 is also reduced, which is also conducive to bending after welding, and the length of a single pole ear 11 can be reduced.

[0067] Figure 3 A schematic structural diagram of an embodiment of an electrode assembly is given. The electrode assembly 1 includes two main bodies 12 stacked in the thickness direction, and the pole ears 11 corresponding to the two main bodies 12 are respectively led out from the outer sides of the main bodies 12 in the width direction, and together with the support plate 52, are respectively bent inwardly from both sides of the guide plate 51 in the width direction.

[0068] Figure 4 An exploded view of an embodiment of a battery cell is given. Two current collecting members include a first current collecting member 5 and a second current collecting member 6 provided at both ends of the top cover plate 2 in the length direction, the first current collecting member 5 is connected to the negative terminal 3, and the second current collecting member 6 is connected to the positive terminal 4. The first current collecting member 5 and the second current collecting member 6 are respectively located on both sides of the electrode assembly 1 in the length direction. In order to ensure the insulation between the electrode assembly 1 and the shell 8, an insulating film 9 is provided between the electrode assembly 1 and the shell 8. The insulating film 9 can be attached to the inner surface of the shell 8, or coated on the outer surface of the electrode assembly 1. The insulating film 9 can be pre-folded into a shape matching the shell 8.

[0069] Based on the overall structure of the battery cell given above, the following reference Fig.12 The structural schematic diagram of the first current collecting member 5 shown in the figure is used to illustrate the improvement of the present invention, but the embodiments given below are not limited to Fig.12 Features in .

[0070] Combination Figure 2 and Fig.12The current collecting component includes a guide plate 51, a support plate 52 and an adapter plate 53. The guide plate 51 is located on the side of the main body 12 along the length direction and extends along the width direction. Preferably, the thickness direction of the guide plate 51 is parallel to the length direction; the support plate 52 is connected to the end of the guide plate 51 along the width direction, and the pole ear 11 is connected to the support plate 52. The height of the support plate 52 is not less than the preset height to reduce the resistance of the current collecting component and prevent the main body from having a large temperature rise during use; the adapter plate 53 is arranged at the top of the guide plate 51 and extends inward along the length direction of the main body 12. The adapter plate 53 is provided with a hole for installing the terminal. The guide plate 51 is provided with a reinforcement portion, which is configured to reduce the deformation of the guide plate 51 toward the side of the main body 12.

[0071] This embodiment of the present invention can increase the cross-sectional bending stiffness of the guide plate 51 in the direction perpendicular to the height direction of the electrode assembly 1 by providing a reinforcement portion on the guide plate 51. After the pole lug 11 and the support plate 52 are folded inward, when pressure is applied to the outside of the pole lug 11 through the flat plate structure, the bending deformation of the guide plate 51 toward the main body 12 can be reduced, and the active material coated on each pole piece in the electrode assembly 1 is prevented from being affected, which can improve the electrochemical performance and safety performance of the battery unit. Moreover, compared with the solution of providing clamping portions on both sides of the guide plate located on the pole lug in the height direction, the embodiment of the present invention can reduce the deformation from the perspective of increasing the stiffness of the current collecting component itself, reduce the precision requirements for the assembly equipment, and prevent stress concentration at the location of the upper clamping portion.

[0072] like Fig.12 As shown, support plates 52 are provided at both side ends of the guide plate 51 in the width direction to improve the reliability of welding and fixing with the pole lug 11 by increasing its own structural strength. The pole lug 11 is attached to the outer side surface of the support plate 52 and folded back together. Figure 8 This is the front view of the battery cell. Fig. 9 For along Figure 8 The figure is a state diagram of the section at the middle DD position and the support plate 52 and the pole ear 11 are not folded back. At this time, the pole ear 11 is in contact with the outer side surface of the support plate 52 and is perpendicular to the guide plate 51. Fig.10 for Figure 8 The DD cross-sectional view in FIG. 1 is a state diagram after the support plate 52 and the pole lug 11 are folded back. Optionally, the support plate 52 is only provided on one side of the guide plate 51 along the width direction.

[0073] refer to Fig.12The reinforcement part includes ribs 511, which extend in the height direction or extend obliquely relative to the height direction to increase the moment of inertia of the guide plate 51 in the cross section perpendicular to the height direction of the electrode assembly 1 to the z-axis, thereby increasing the bending stiffness of the cross section of the guide plate 51 in the direction perpendicular to the height direction of the electrode assembly 1. The ribs 511 extending in the height direction can achieve a better reinforcement effect, and the ribs 511 can adopt a continuous structure or a discontinuous structure. In addition, the reinforcement part can also include a plurality of small bumps arranged according to a preset rule.

[0074] The reinforcement part may include one rib 511, or include a plurality of ribs 511 arranged at intervals, each rib 511 is independently arranged, and each rib 511 may be arranged in parallel along the vertical direction, so that the cross-sectional bending stiffness of the current collecting component in the height direction is relatively uniform, the overall bending deformation can be reduced, and the processing difficulty is low. Fig.12 As shown, three ribs 511 arranged in parallel along the vertical direction are provided on the guide plate 51. Optionally, the ribs 511 can also be arranged in a staggered manner, such as horizontally and vertically staggered or obliquely staggered grid-like ribs.

[0075] refer to Fig.14 , for example, the side of the reinforcement part such as the rib 511 away from the electrode assembly 1 protrudes outward relative to the guide plate 51. This structure can reduce the space occupied by the reinforcement part on the side facing the electrode assembly 1, and reduce the deformation of the current collecting member without reducing the energy density of the main body. Alternatively, the reinforcement part can also protrude toward the side of the electrode assembly 1.

[0076] Fig.13 is the main view of the current collecting component. Fig.14 for Fig.13 In the EE cross-sectional view, the side of the rib 511 close to the electrode assembly 1 is recessed inward relative to the guide plate 51. During the operation of the battery cell, the electrolyte generates gas. After the gas is discharged from both sides of the electrode assembly 1 along the length direction, it can flow along the flow channel formed by the recessed part of the rib 511 and be discharged from the upper and lower positions of the current collecting member. In addition, the recessed part can also buffer the gas discharged from both sides of the electrode assembly 1, so that the gas in the electrolyte can escape smoothly, reduce bubbles in the electrolyte, and prevent lithium precipitation in the battery cell.

[0077] like Fig.12 As shown, the reinforcement portion covers the height area of ​​the pole lug 11 in the height direction. Fig.12 In the embodiment, the top of the rib 511 is higher than the top of the tab 11, and the bottom of the rib 511 is lower than the bottom of the tab 11. This structure can maximize the cross-sectional bending rigidity of the guide plate 51, and when the tab 11 and the support plate 52 are flattened by the flat plate structure, the deformation of the guide plate 51 toward the main body 12 can be minimized.

[0078] like Fig.12 As shown, the support plate 52 includes a connecting portion 521 and a bending portion 522, the bending portion 522 is connected to the guide plate 51 and bent into an arc shape, the pole ear 11 is connected to the connecting portion 521, and is integrally folded back along the outer surface of the bending portion 522 and the connecting portion 521 to the side of the guide plate 51 away from the main body 12. In this structure where the pole ear 11 is bent inward, the width of the battery cell depends on the width of the main body 12, thereby reducing the space occupied by the support plate 52 in the width direction of the electrode assembly 1, thereby reducing the width of the battery cell.

[0079] Still refer to Fig.12 The rib 511 includes a first rib, which is covered by the connecting portion 521 in the width direction, has a first protruding height relative to the guide plate 51, and the bent portion has a third protruding height relative to the guide plate 51, and the first protruding height is less than or equal to the third protruding height. This structure can prevent the connecting portion 521 from tilting and warping, and prevent the current collecting component from occupying additional space on the side of the main body 12 along the length direction, making it easier to install it in the housing 8, and also facilitate the arrangement of an insulating plate on the outer side of the tab 11.

[0080] like Fig.12 and Fig.14 As shown, two support plates 52 are provided, and the two support plates 52 are respectively connected to the two ends of the guide plate 51 in the width direction and are bent relative to each other. In the width direction, the connecting parts 521 of the two support plates 52 are arranged at intervals. The ribs 511 also include second ribs, the first ribs are provided with two sections, the two sections of the first ribs are covered by different connecting parts 521, the second ribs are located between the two sections of the first ribs, and the second ribs are located in the interval area of ​​the two connecting parts 521. This structure can prevent the second ribs from overlapping with the connecting parts 521, and can reduce the occupied space.

[0081] Furthermore, the second rib has a second protruding height relative to the guide plate 51 , and the second protruding height is greater than or equal to the first protruding height.

[0082] For example, in a specific embodiment, one first rib, the second rib and another first rib are arranged side by side in the width direction, the first protrusion height of the two first ribs is 0≤h1≤2mm, preferably 0.3≤h1≤0.9mm, and the second protrusion height of the second rib is 0≤h2≤3mm, preferably 0.3≤h2≤2mm. The first protrusion height and the second protrusion height need to consider both the space and the reinforcement effect when designing.

[0083] This structure designs the second rib located in the interval area between the two support plates 52 to have a larger protruding height, which can maximize the bending stiffness of the guide plate 51 in the middle area along the width direction, thereby further reducing the deformation of the guide plate 51, and also preventing the tab 11 from tilting and warping after bending. At the same time, the first rib covered by the support plate 52 after bending is designed to have a smaller protruding height, which can minimize the size of the current collecting member on the side of the electrode assembly 1 while ensuring the bending stiffness of the guide plate 51, and increase the energy density of the electrode assembly when the battery cell size is constant.

[0084] On the basis of the above embodiments, according to the working characteristics of the first current collecting member 5 corresponding to the negative terminal 3 and the second current collecting member 6 corresponding to the positive terminal 4 , the first current collecting member 5 and the second current collecting member 6 can be designed to have different structures.

[0085] First, embodiments that may be adopted by the first current collecting member 5 are given. Figure 5 This is a top view of the battery cell of the present invention, formed after cutting along the AA section. Figure 6 The cross-sectional view shown schematically illustrates the side structure of the first current collecting member 5 and the second current collecting member 6 .

[0086] In order to more clearly see the specific structure of the first current collecting member 5, Fig. 7A for Figure 6 Enlarged view of point B. The battery cell also includes a top cover plate 2 and a lower insulating member 7, the terminals are arranged on the top cover plate 2, and the lower insulating member 7 is arranged between the top cover plate 2 and the electrode assembly 1. The two current collecting components include a first current collecting component 5 located on one side of the electrode assembly 1, and the two terminals include a negative terminal 3. The first current collecting component 5 connects the pole ear 11 on the side thereof to the negative terminal 3, and the reinforcement portion of the first current collecting component 5 extends in the height direction to the bottom surface of the lower insulating member 7. This structure can extend the length of the reinforcement portion such as the rib 511 in the height direction as much as possible while ensuring that the reinforcement portion does not interfere with the lower insulating member 7, thereby increasing the overall stiffness of the current collecting component in the height direction and minimizing the deformation when the pole ear 11 is flattened. As shown Fig.11A As shown, the support portion 52 partially covers the rib 511 in the height direction.

[0087] like Fig. 7AAs shown, the current collecting member also includes a clamping portion 512, which is provided at the bottom of the guide plate 51 and protrudes toward the outside away from the electrode assembly 1 as a whole. In order to give full play to the role of the clamping portion 512, the bottom end of the reinforcing portion extends downward to the top of the adjacent clamping portion 512, but there is still a preset gap between the two, and the bottom end of the clamping portion 512 is a free end and maintains the protrusion height. When it is necessary to flatten the bent pole lug 11, a tooling can be provided between the clamping portion 512 and the electrode assembly 1 for support to reduce the deformation of the guide plate 51 toward the main body 12 when flattening the pole lug 11.

[0088] Specifically, the rib 511 protrudes toward a side away from the electrode assembly 1 relative to the plane where the guide plate 51 is located to form a convex ridge, and the rib 511 extends along the height direction of the guide plate 51. The top of the rib 511 extends upward to the bottom surface of the lower insulating member 7, and the bottom of the rib 511 extends downward to connect with the clamping portion 512. This structure can maximize the length of the rib 511 along the height direction, thereby increasing the rigidity of the first current collecting member 5 in the entire height direction, and minimize the deformation when the tab 11 is flattened.

[0089] like Fig. 7A and Figure 7B As shown, in the length direction, the surface of the clamping portion 512 away from the guide plate 51 is not higher than the surface of the tab 11 away from the guide plate 51 after being folded back. In this structure, when the clamping portion 512 is provided, the size of the battery unit in the length direction will not be increased; and when the insulating plate is provided on the side of the electrode assembly 1 in the length direction, the insulating plate can also be fitted with the tab 11, thereby increasing the insulation reliability, and the insulating plate can also be installed more firmly by increasing the fitting area of ​​the insulating plate.

[0090] Next, an embodiment of the second current collecting member 6 that can be used is given. Figure 7B As shown, the two current collecting members include a second current collecting member 6 located on the other side of the electrode assembly 1, and the two terminals include a positive terminal 4. The second current collecting member 6 connects the pole ear 11 on the side thereof to the positive terminal 4. The second current collecting member 6 also includes a heat dissipation portion 54, and the heat dissipation portion 54 is provided in the area of ​​the guide plate 51 located above the pole ear 11. Since the second current collecting member 6 is usually made of aluminum material corresponding to the positive terminal 4, and the first current collecting member 5 is usually made of copper material corresponding to the negative terminal 3, when the current flows upward along the guide plate 51 of the second current collecting member 6 to the adapter plate 53, it needs to pass through the bending structure, which will generate a large amount of heat, and the heat dissipation performance of aluminum is poor compared with that of copper. By providing the heat dissipation portion 54, the heat release can be accelerated, and the temperature of the local area of ​​the second current collecting member 6 is prevented from being too high to affect the battery performance, and the safety of the battery unit operation is improved. Moreover, by providing the heat dissipation portion 54, the rigidity of the second current collecting member 6 can also be increased.

[0091] like Fig.15 As shown, the heat dissipation portion 54 includes a thickened portion, which is disposed on the side of the guide plate 51 away from the electrode assembly 1. For example, heat dissipation ribs may be disposed on the thickened portion to further optimize the heat dissipation effect by increasing the heat dissipation surface. The protruding direction of the reinforcement portion and the thickened portion are disposed on the same side of the guide plate 51, which can reduce the space occupied by the second current collecting member 6 in the length direction, so as to improve the energy density of the battery cell.

[0092] For example, the thickened portion may be a rectangular plate structure, located in the upper region of the guide plate 51, and its width is adapted to the width of the guide plate 51, so as to optimize the heat dissipation effect by increasing the heat dissipation surface area. The thickened portion may be connected to the guide plate 51 by welding, or the thickened portion may be formed by folding to fit and fix with the guide plate 51.

[0093] Still refer to Fig.15 , the reinforcement portion of the second current collecting member 6 extends to the bottom surface of the heat dissipation portion 54 in the height direction. For example, the top of the rib 511 can extend to the bottom of the adjacent thickened portion, and the bottom of the rib 511 extends to the adjacent clamping portion 512. This structure can take into account both the heat dissipation and rigidity of the second current collecting member 6. On the basis of ensuring the heat dissipation effect, the length of the rib 511 in the height direction can be maximized, thereby increasing the rigidity of the first current collecting member 5 and reducing the deformation when the tab 11 is flattened.

[0094] like Fig.16 As shown, the curved portion 522 has at least one of a through slot 523 and a groove 524 extending in the height direction. The through slot 523 is provided in the middle area of ​​the curved portion 522 in the height direction. For example, a slender rectangular groove extending in the height direction is used. Due to the reduction of the force-bearing area, the strength of the curved portion 522 can be reduced under a certain pressure, and the stress generated during bending is smaller. Moreover, the size of the through slot 523 should not be too small to ensure the flow requirements of the current collecting component. The groove 524 is provided on the inner side of the curved portion 522 at least one place above and below the through slot 523. For example, the groove is a notch extending in the height direction provided on the inner side of the curved portion 522, which can help weaken the strength of the bending area and accurately position the bending part. Fig.17 This is the front view of the current collecting component. Fig.18 for Fig.17 FF cross-sectional view in.

[0095] This structure can reduce the strength of the support plate 52 in the bending area, making it easy to fold back the support plate 52 of the current collecting component. In addition, during the folding process, it can avoid transferring the stress in the bending area to other areas of the current collecting component as much as possible, so as to protect the electrode assembly 1 from mechanical damage and improve the electrochemical performance in the battery cell.

[0096] In order to illustrate the effects of the various improvements of the present invention, the advantages are analyzed by comparing experimental data. The following test data is given for an embodiment of a current collecting component with support plates 52 at both ends. In the process of folding back the pole ear 11 and the support plate 52, it includes pre-folding and final folding. The pre-folding is to fold the support plate 52 perpendicular to the guide plate 51 inwardly to a certain angle, and the final folding is to fold the support plate 52 inwardly to its position. In this process, the deformation amount of the guide plate 51 in the middle area along the height direction is detected by a micrometer.

[0097] In order to compare the effect of each structural improvement separately in the experiment, four experimental groups are given. Among them, the Base group does not have a reinforcement part on the guide plate 51 of the current collecting component, and only sets clamping parts in the upper and lower areas of the pole ear 11; Group A sets three sections of ribs 511 along the height direction on the outer surface of the guide plate 51, and the ribs 511 extend to the position adjacent to the upper and lower clamping parts; Group B is different from Group A in that a thickened part is set on the outer side of the top area of ​​the guide plate 51 as a heat dissipation part 54; Group C is different from Group A in that a through groove 523 is set in the bending area of ​​the support plate 52. Table 1 below shows the deformation of the first current collecting component 5 and the second current collecting component 6 toward the electrode assembly 1 after folding back.

[0098] Table 1 Deformation of current collecting components during folding

[0099]

[0100] As can be seen from Table 1, on the basis of the Base group, the deformation of the guide plate 51 in the two current collecting components can be reduced by adding ribs 511 to the A group; on the basis of the A group, the deformation can be further reduced by replacing the upper clamping part with the heat dissipation part 54 through the B group; on the basis of the A group, the deformation can be further reduced by adding through grooves 523 through the C group. By comparison, the effect of adding ribs 511 on reducing the deformation of the guide plate 51 is the most significant. Therefore, in some specific embodiments, the ribs 511, the heat dissipation part 54 and the through grooves 523 can be combined to minimize the deformation of the guide plate 51; or in other embodiments, the heat dissipation part 54 or the through grooves 523 can be superimposed on the ribs 511.

[0101] Table 2 below shows the variance of the deformation of the guide plate 51 obtained by testing a plurality of battery cells.

[0102] Table 2 Standard deviation of deformation of the guide plate 51 of the current collecting component after folding back

[0103] Group First current collecting member 5 Second current collecting member 6 Base group 0.23 0.34 Group A 0.18 0.28 Group B 0.05 0.17 Group C 0.07 0.16

[0104] As can be seen from Table 2, by testing multiple samples, on the basis of the Base group, by adding ribs 511 to the A group, the variance of the deformation of the guide plate 51 in the two current collecting components can be reduced; on the basis of the A group, by replacing the upper clamping part with the heat dissipation part 54 through the B group, the variance of the deformation can be further reduced; on the basis of the A group, by adding through slots 523 through the C group, the variance of the deformation can also be further reduced. Therefore, through the structural improvement of the present invention, the deformation of the guide plate 51 can be made more stable, the precision requirements for the fixture can be reduced, and the stability of batch production can be improved.

[0105] The above is a detailed introduction to a battery cell and a battery module provided by the present invention. Specific embodiments are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A battery cell, characterized in that: include: Top cover plate (2); An electrode assembly (1) comprises a main body (12) and an electrode lug (11) extending from an end portion of the main body (12) along a length direction; two terminals, arranged on the top cover plate (2) and located on the top of the electrode assembly (1), the two terminals comprising a negative terminal (3) and a positive terminal (4); and Two current collecting members, respectively electrically connecting the tabs (11) on both sides of the main body (12) to the terminal on the same side, the two current collecting members comprising a first current collecting member (5) and a second current collecting member (6) respectively located on both sides of the electrode assembly (1), the first current collecting member (5) connecting the tab (11) on the side thereof to the negative terminal (3), and the second current collecting member (6) connecting the tab (11) on the side thereof to the positive terminal (4); The current collecting component comprises a guide plate (51) and a support plate (52); the guide plate (51) is located on one side of the main body (12) along the length direction and extends along the width direction; a reinforcing portion is provided on the guide plate (51) and is configured to reduce deformation of the guide plate (51) toward one side of the main body (12); the support plate (52) is connected to an end of the guide plate (51) along the width direction; the pole ear (11) is bent relative to the length direction and connected to the support plate (52).

2. The battery cell according to claim 1, characterized in that: The reinforcement portion comprises a rib (511), wherein the rib (511) extends along a height direction, or extends obliquely relative to the height direction.

3. The battery cell according to claim 2, characterized in that: The reinforcement portion comprises a plurality of ribs (511) arranged at intervals, and the ribs (511) are arranged independently or in a staggered manner.

4. The battery cell according to claim 2, characterized in that: A side of the reinforcement portion close to the electrode assembly (1) is recessed inwardly relative to the guide plate (51).

5. The battery cell according to claim 1, characterized in that: A side of the reinforcement portion away from the electrode assembly (1) protrudes outwardly relative to the guide plate (51).

6. The battery cell according to claim 5, characterized in that: The support plate (52) comprises a connecting portion (521) and a bent portion (522); the bent portion (522) is connected to the guide plate (51) and is bent into an arc shape; the pole lug (11) is connected to the connecting portion (521) and is folded back as a whole along the surface of the bent portion (522) to a side of the guide plate (51) away from the main body (12).

7. The battery cell according to claim 6, characterized in that: The reinforcing portion comprises a rib (511), the rib (511) comprising a first rib, the first rib being covered by the connecting portion (521) in the width direction, the first rib having a first protruding height relative to the guide plate (51), the bent portion (522) having a third protruding height relative to the guide plate (51), the first protruding height being less than or equal to the third protruding height.

8. The battery cell according to claim 7, characterized in that: Two support plates (52) are provided, and the two support plates (52) are respectively connected to two ends of the guide plate (51) along the width direction and are bent relative to each other, and along the width direction, the connection parts (521) of the two support plates (52) are arranged at intervals; The rib (511) further comprises a second rib, the first rib being provided with two sections, the two sections of the first rib being covered by the connecting portions (521) on both sides, the second rib being located between the two sections of the first rib, and the second rib being located in the interval area between the two connecting portions (521).

9. The battery cell according to claim 8, characterized in that: The second rib has a second protruding height relative to the guide plate (51), and the second protruding height is greater than or equal to the first protruding height.

10. The battery cell according to claim 6, characterized in that: The curved portion (522) has at least one of a through slot (523) and a groove (524) extending in the height direction, the through slot (523) being arranged in a middle area of ​​the curved portion (522) in the height direction, and the groove (524) being arranged on the inner side of the curved portion (522) and located at least one of an area above and below the through slot (523).

11. The battery cell according to claim 1, characterized in that: The reinforcing portion covers the supporting plate (52) in the height direction.

12. The battery cell according to claim 1, characterized in that It also comprises a lower insulating member (7), wherein the lower insulating member (7) is arranged between the top cover plate (2) and the electrode assembly (1); The reinforcement portion of the first current collecting member (5) extends to the lower side of the lower insulator (7) in the height direction.

13. The battery cell according to claim 1, characterized in that The second current collecting member (6) further comprises a heat dissipation portion (54), wherein the heat dissipation portion (54) is provided in a region of the guide plate (51) located above the support plate (52).

14. The battery cell according to claim 13, characterized in that: The reinforcement portion of the second current collecting member (6) extends to the lower side of the heat dissipation portion (54) in the height direction.

15. The battery cell according to claim 1, characterized in that The current collecting component further comprises a clamping portion (512), wherein the clamping portion (512) is arranged at the bottom of the guide plate (51) and protrudes as a whole towards a side away from the electrode assembly (1).

16. The battery cell according to claim 15, characterized in that Along the length direction, the surface of the clamping portion (512) away from the guide plate (51) is not higher than the surface of the pole lug (11) away from the guide plate (51) after being folded back.

17. A battery module, characterized in that: include: A plurality of battery cells as described in any one of claims 1 to 16, wherein each of the battery cells is arranged side by side along the width direction.

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