Battery cell and battery pack

Abstract

The application relates to the technical field of new energy batteries, and discloses a battery monomer and a battery pack, the battery monomer has a first direction and a second direction intersecting with each other, and the battery monomer comprises: a shell having a containing cavity; an electrode assembly comprising a main body part and a tab, the main body part is arranged in the containing cavity, the tab comprises a connecting part and a bent part, the bent part has a first end and a second end; a cover plate connected with the shell and sealing the containing cavity; a support comprising a supporting rod connected with the cover plate and a reinforcing rib connected with the supporting rod, the supporting rod and the reinforcing rib are both arranged between the bent part and the main body part, along the first direction, the supporting rod supports the first end, and the reinforcing rib supports the second end. The supporting rod and the reinforcing rib of the support support the first end and the second end of the bent part of the tab along the first direction respectively, the first end of the bent part of the tab is prevented from being inserted into the main body part of the electrode assembly during bending to cause short circuit of the electrode assembly, and the safety of the battery monomer is improved.

Description

Technical Field

[0001] This application relates to the field of new energy battery technology, and in particular to a battery cell and battery pack. Background Technology

[0002] Lithium-ion batteries are widely used as power sources in new energy vehicles, and the safety requirements for lithium-ion batteries are becoming increasingly stringent, with preventing internal short circuits being particularly important. A lithium-ion battery mainly consists of a casing, electrode assembly, and cover plate. The electrode assembly has tabs leading out, and the cover plate has terminals, which are typically connected to the tabs by adapter plates.

[0003] After the tabs are led out from the electrode assembly, they need to be bent and welded to the adapter plate. During bending, the tabs may become indented or collapse at the end. If the tab is bent inward and inserted into the electrode assembly, it can cause the diaphragms of the electrode assembly to connect, forming a circuit. If the end of the tab collapses and overlaps with the non-isotropic foil of the electrode assembly, it can cause the foils of different polarities to connect, forming a circuit, thus leading to a short circuit in the battery cell. A short circuit in a battery cell will cause its performance to degrade and may even lead to high-risk safety issues. Utility Model Content

[0004] The purpose of this application is to provide a single battery cell to solve the problem of short circuits caused by the bending and collapsing of the tabs in existing lithium-ion batteries; this application also provides a battery pack using this single battery cell.

[0005] To achieve the above objectives, this application provides a battery cell having intersecting first and second directions, the battery cell comprising:

[0006] The outer shell has a receiving cavity;

[0007] An electrode assembly includes a main body and an electrode tab. The main body is disposed in the receiving cavity. The electrode tab includes a connecting portion connected to the main body and a bent portion bent toward the main body. The bent portion has a first end connected to the connecting portion and a second end away from the connecting portion.

[0008] A cover plate is connected to the outer shell and seals the receiving cavity;

[0009] The bracket includes a support rod extending along the second direction and a reinforcing rib connected to the support rod. The support rod is fixedly connected to the cover plate. Both the support rod and the reinforcing rib are located between the bent portion and the main body portion. Along the first direction, the support rod supports the first end, and the reinforcing rib is fixedly connected to the second end and supports the second end.

[0010] In some embodiments, the cover plate includes a plate body and a lower plastic piece connected to the plate body, the lower plastic piece being located between the plate body and the electrode assembly along the first direction, and the support rod being detachably connected to the lower plastic piece.

[0011] In some embodiments, the lower plastic is provided with slots at both ends along the second direction, and the support rod includes a rod body, a first slot and a second slot, the first slot and the second slot are respectively provided at the ends of the rod body along the second direction, and the first slot and the second slot are respectively embedded in the slots along the second direction.

[0012] In some embodiments, the battery cell further includes a third direction that intersects the first direction and the second direction in pairs. Along the third direction, the size of the first card holder is L1 mm and the size of the second card holder is L2 mm, satisfying: L1 > L2.

[0013] In some embodiments, along the first direction, a limiting groove is provided on the side of the lower plastic away from the plate body, and the support rod further includes a limiting plate. The limiting plate is connected between the rod body and the first card platform and between the rod body and the second card platform. The limiting plate is embedded in the limiting groove along the first direction.

[0014] In some embodiments, two electrode assemblies are arranged symmetrically about the second direction, and two support rods are arranged at intervals along the third direction. Each support rod corresponds to one of the electrode assemblies, and the reinforcing rib connects the two support rods.

[0015] In some embodiments, the cover plate is further provided with a pressure relief hole, the bracket further includes a frame body disposed opposite to the pressure relief hole along the first direction, the support rod is fixedly connected to the frame body, the frame body is provided with an air guide hole, and the air guide hole penetrates the frame body along the first direction.

[0016] In some embodiments, the cover plate is further provided with an injection hole that penetrates the cover plate along the first direction. The bracket further includes a support plate and a baffle. The support plate is connected between the reinforcing rib and the frame. The baffle is disposed on the side of the support plate away from the cover plate along the first direction. The baffle and the support plate form a guide groove extending along the second direction. The guide groove connects the injection hole and the receiving cavity.

[0017] In some embodiments, the air guide hole includes at least one of a rectangular hole, a circular hole, or an elliptical hole, and the air guide hole array is provided with multiple holes.

[0018] This application also provides a battery pack, including the battery cells described in any of the above technical solutions.

[0019] Compared with the prior art, the battery cell and battery pack of this application embodiment have the following advantages: the bracket is fixedly connected to the cover plate by a support rod extending along the second direction. The support rod and reinforcing rib of the bracket support the first end and the second end of the bent portion of the electrode tab along the first direction, respectively, to prevent the first end of the bent portion of the electrode tab from inserting into the main body of the electrode assembly during bending, which would cause a short circuit in the electrode assembly. The reinforcing rib can improve the strength of the bracket and at the same time support and fix the second end of the bent portion of the electrode tab, preventing a short circuit in the electrode assembly of the battery cell and improving the safety of the battery cell. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the exploded structure of a single battery cell of this application;

[0021] Figure 2 yes Figure 1 A schematic diagram of the support structure for a single battery cell;

[0022] Figure 3 yes Figure 2 Top view of the support structure;

[0023] Figure 4 yes Figure 2 A structural schematic diagram of the support from another perspective;

[0024] Figure 5 yes Figure 4 A magnified view of the support structure at point K;

[0025] Figure 6 yes Figure 1 A schematic diagram of the lower plastic structure of a single battery cell;

[0026] Figure 7 yes Figure 6 A magnified view of a portion of the lower plastic section A;

[0027] Figure 8 yes Figure 1 A schematic diagram of the assembly structure of the electrode assembly and support of a single battery cell.

[0028] In the diagram, 1 is the outer shell, 11 is the receiving cavity, 2 is the electrode assembly, 21 is the main body, 22 is the electrode tab, 221 is the connecting part, 222 is the bending part, 2221 is the first end, 2222 is the second end, 3 is the cover plate, 31 is the plate body, 32 is the lower plastic, 321 is the slot, 322 is the limiting slot, 4 is the bracket, 41 is the support rod, 411 is the rod body, 412 is the first locking platform, 413 is the second locking platform, 414 is the limiting plate, 4141 is the end plate, 4142 is the connecting plate, 42 is the reinforcing rib, 43 is the frame body, 431 is the air duct, 44 is the support plate, 45 is the baffle, 46 is the flow channel, 5 is the pressure relief hole, 6 is the liquid injection hole, Z is the first direction, Y is the second direction, and X is the third direction. Detailed Implementation

[0029] The specific embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this application, but are not intended to limit the scope of this application.

[0030] A preferred embodiment of a battery cell in this application, such as... Figures 1 to 8 As shown, the battery cell has intersecting first direction Z and second direction Y. In this embodiment, the battery cell is a square battery, the first direction Z is the height direction of the battery cell, the second direction Y is the width direction of the battery cell, and the first direction Z and the second direction Y are perpendicular.

[0031] The battery cell includes a casing 1, an electrode assembly 2, a cover plate 3, and a support 4. The casing 1 has a receiving cavity 11, with an opening at one end along the first direction Z. The electrode assembly 2 is disposed within the receiving cavity 11. The cover plate 3 is fixedly connected to the casing 1 and seals the opening of the receiving cavity 11, thus sealing the electrode assembly 2 within the receiving cavity 11 and providing protection for it. The support 4 is an insulating component, disposed between the cover plate 3 and the electrode assembly 2, and is used to support the tabs 22 of the electrode assembly 2.

[0032] The electrode assembly 2 includes a main body 21 and an electrode tab 22. The main body 21 is disposed in the receiving cavity 11. The main body 21 is the main structure of the electrode assembly 2. It extends from one side of the main body 21 to be electrically connected to the electrode post on the cover plate 3 of the battery cell through an adapter piece.

[0033] like Figure 1 and Figure 8 As shown, the tab 22 includes a connecting portion 221 and a bending portion 222. The connecting portion 221 is connected to one end of the main body portion 21, and the bending portion 222 bends toward the main body portion 21 of the electrode assembly 2. The bending portion 222 is formed by bending the portion of the tab 22 extending out of the main body portion 21. The bending portion 222 has a first end 2221 and a second end 2222. The first end 2221 is the end connected to the connecting portion 221, and the second end 2222 is the end away from the connecting portion 221.

[0034] like Figures 2 to 4 As shown, the bracket 4 includes a support rod 41 and a reinforcing rib 42. The support rod 41 extends along the second direction Y and is fixedly connected to the cover plate 3. The reinforcing rib 42 is fixedly connected to the support rod 41. The bracket 4 is fixedly connected to the cover plate 3 as a whole through the support rod 41. Both the support rod 41 and the reinforcing rib 42 are located between the bent portion 222 and the main body portion 21. The reinforcing rib 42 is fixedly connected to the second end 2222. Along the first direction Z, the support rod 41 supports the first end 2221, and the reinforcing rib 42 supports the second end 2222.

[0035] like Figure 8 As shown, the support rod 41 and the reinforcing rib 42 respectively support the first end 2221 and the second end 2222 of the bent portion 222 of the electrode tab 22, preventing the first end 2221 of the bent portion 222 from inserting into the main body 21 and the second end 2222 from overlapping with the non-isotropic foil. The reinforcing rib 42 can improve the strength of the bracket 4, so that the bracket 4 can stably support the electrode tab 22. In addition, the second end 2222 is the large surface of the electrode tab 22. After the second end 2222 is fixedly connected to the reinforcing rib 42, the reinforcing rib 42 can work with the cover plate 3 to stably compress the large surface of the electrode tab 22 along the first direction Z.

[0036] The battery cell's support 4 is fixedly connected to the cover plate 3 via a support rod 41 extending along the second direction Y. The support rod 41 and reinforcing rib 42 of the support 4 support the first end 2221 and the second end 2222 of the bent portion 222 of the tab 22 along the first direction Z, respectively, to prevent the first end 2221 of the bent portion 222 of the tab 22 from inserting into the main body 21 of the electrode assembly 2 during bending, thus preventing a short circuit in the electrode assembly 2. The reinforcing rib 42 can improve the strength of the support 4, and at the same time support and fix the second end 2222 of the bent portion 222 of the tab 22, preventing the second end 2222 from touching the non-isotropic foil of the main body 21, thus preventing a short circuit in the electrode assembly 2 of the battery cell and improving the safety of the battery cell.

[0037] In some embodiments, the cover plate 3 includes a plate body 31 and a lower plastic 32 connected to the plate body 31. Along the first direction Z, the lower plastic 32 is located between the plate body 31 and the electrode assembly 2, and the support rod 41 is detachably connected to the lower plastic 32.

[0038] The lower plastic 32 can insulate and isolate the plate 31 and the electrode assembly 2, preventing short circuits after the electrode assembly 2 comes into contact with the plate 31. The support rod 41 is detachably connected to the lower plastic 32. The support rod 41, as an insulating component, together with the lower plastic 32, provides insulation and isolation between the electrode assembly 2 and the plate 31. The detachable connection also facilitates the assembly and disassembly of the bracket 4.

[0039] In some embodiments, the lower plastic 32 is provided with slots 321 at both ends along the second direction Y. The support rod 41 includes a rod body 411, a first slot 412 and a second slot 413. The first slot 412 and the second slot 413 are respectively provided at the ends of the rod body 411 along the second direction Y. The first slot 412 and the second slot 413 are respectively embedded in the slots 321 along the second direction Y.

[0040] The support rod 41 has a first locking platform 412 and a second locking platform 413 formed at both ends in the second direction Y. The first locking platform 412 and the second locking platform 413 are inserted into the locking groove 321 along the second direction Y to achieve a locking connection. The locking connection can fix the support rod 41 and facilitate disassembly. In this embodiment, the locking groove 321 is formed on the end face of the lower plastic 32, and the opening of the locking groove 321 faces the outer shell 1 along the second direction Y. The first locking platform 412 and the second locking platform 413 face each other.

[0041] In some embodiments, the battery cell further includes a third direction X that intersects the first direction Z and the second direction Y in pairs. Along the third direction X, the size of the first card holder 412 is L1 mm and the size of the second card holder 413 is L2 mm, satisfying: L1 > L2.

[0042] like Figure 3 As shown, the first card holder 412 and the second card holder 413 have different dimensions along the third direction X, which constitutes a foolproof design between the first card holder 412 and the second card holder 413 to prevent incorrect assembly orientation of the bracket 4. In this embodiment, the dimensions of the card slot 321 are adapted to the first card holder 412 and the second card holder 413 respectively to ensure the foolproof effect. In other embodiments, the first card holder 412 and the second card holder 413 may also adopt different cross-sectional shapes to produce a foolproof effect.

[0043] In some embodiments, along the first direction Z, the lower plastic 32 is provided with a limiting groove 322 on the side away from the plate 31, and the support rod 41 also includes a limiting plate 414. The limiting plate 414 is connected between the rod 411 and the first carding platform 412 and between the rod 411 and the second carding platform 413. The limiting plate 414 is embedded in the limiting groove 322 along the first direction Z.

[0044] like Figures 6 to 7 As shown, the limiting plate 414 of the support rod 41 is embedded in the limiting groove 322 of the lower plastic 32 along the first direction Z. The limiting groove 322 can limit the limiting plate 414 along the second and third directions X, thereby limiting the bracket 4 and ensuring that the first locking platform 412 and the second locking platform 413 of the bracket 4 can be embedded in the locking groove 321 of the lower plastic 32, avoiding misalignment of the bracket 4. In addition, the limiting plate 414 embedded in the limiting groove 322 can ensure that the bottom of the lower plastic 32 is flat, ensuring the reliability of the cover plate 3 compressing the electrode assembly 2 through the lower plastic 32.

[0045] like Figures 4 to 5 As shown, in this embodiment, the limiting groove 322 is a rectangular groove, and the limiting plate 414 includes two end plates 4141 and a connecting plate 4142 connected between the two end plates. The connecting plate 4142 and the two end plates 4141 are integrated into a U-shaped structure. One end plate 4141 is connected to the rod body 411, and the other end plate 4141 is connected to the first locking platform 412 or the second locking platform 413. The connecting plate 4142 in the middle is embedded in the limiting groove 322 along the first direction Z.

[0046] In some embodiments, two electrode assemblies 2 are symmetrically arranged about the second direction Y, and two support rods 41 are spaced apart along the third direction X. The support rods 41 correspond one-to-one with the electrode assemblies 2, and the reinforcing ribs 42 connect the two support rods 41.

[0047] Two electrode assemblies 2 are symmetrically arranged. Each electrode assembly 2 includes a main body 21 and an electrode tab 22. The electrode tabs 22 of the two electrode assemblies 2 are symmetrical about the second direction Y as an axis. Two support rods 41 can support the electrode tabs 22 of the two electrode assemblies 2 respectively. The reinforcing rib 42 is connected between the two support rods 41, so that the support rods 41 and the reinforcing rib 42 form a whole, increasing the overall strength of the bracket 4.

[0048] In some embodiments, the cover plate 3 is further provided with a pressure relief hole 5, and the bracket 4 is further provided with a frame body 43 disposed opposite to the pressure relief hole 5 along the first direction Z. The support rod 41 is fixedly connected to the frame body 43, and the frame body 43 is provided with an air guide hole 431, which penetrates the frame body 43 along the first direction Z.

[0049] The frame 43 of the bracket 4 is arranged opposite to the pressure relief hole 5 along the first direction Z, and a through vent 431 is opened on the frame 43. The vent 431 can form a gas flow channel, which does not affect the venting of the pressure relief hole 5 under the thermal runaway state of the battery cell, thus ensuring the reliability of venting during thermal runaway.

[0050] In some embodiments, the cover plate 3 is further provided with an injection hole 6, which penetrates the cover plate 3 along the first direction Z. The bracket 4 also includes a support plate 44 and a baffle 45. The support plate 44 is connected between the reinforcing rib 42 and the frame 43. The baffle 45 is located on the side of the support plate 44 away from the cover plate 3 along the first direction Z. The baffle 45 and the support plate 44 form a guide groove 46 extending along the second direction Y. The guide groove 46 connects the injection hole 6 and the receiving cavity 11.

[0051] The support plate 44 and the baffle 45 are provided on the bracket 4. The support plate 44 can connect the reinforcing rib 42 and the frame 43 into a whole, increasing the overall strength of the bracket 4. The baffle 45 can block the electrolyte when it is injected, so that the electrolyte flows in the second direction Y in the guide groove 46, changing the flow direction of the electrolyte and preventing the electrolyte from directly scouring the diaphragm. Keeping the diaphragm intact can prevent the electrode assembly 2 from short-circuiting with the outer shell 1, improving the safety of the battery cell.

[0052] In some embodiments, the air guide hole 431 includes at least one of a rectangular hole, a circular hole, or an elliptical hole, and the air guide hole 431 array is provided with multiple holes.

[0053] The air vent 431 is formed by multiple rectangular holes, and the frame 43 forms a reinforcing structure between each air vent 431, which ensures the reliability of exhaust while also ensuring the overall structural strength of the support 4.

[0054] In summary, the embodiments of this application provide a battery cell and a battery pack, wherein the bracket is fixedly connected to the cover plate by a support rod extending along the second direction. The support rod and the reinforcing rib of the bracket support the first end and the second end of the bent portion of the electrode tab along the first direction, respectively, to prevent the first end of the bent portion of the electrode tab from inserting into the main body of the electrode assembly during bending, thereby causing a short circuit in the electrode assembly. The reinforcing rib can improve the strength of the bracket and at the same time support and fix the second end of the bent portion of the electrode tab, preventing a short circuit in the electrode assembly of the battery cell and improving the safety of the battery cell.

[0055] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of this application, and these improvements and substitutions should also be considered within the scope of protection of this application.

Claims

1. A battery cell, characterized in that, The battery cell has intersecting first and second directions, and the battery cell includes: The outer shell has a receiving cavity; An electrode assembly includes a main body and an electrode tab. The main body is disposed in the receiving cavity. The electrode tab includes a connecting portion connected to the main body and a bent portion bent toward the main body. The bent portion has a first end connected to the connecting portion and a second end away from the connecting portion. A cover plate is connected to the outer shell and seals the receiving cavity; The bracket includes a support rod extending along the second direction and a reinforcing rib connected to the support rod. The support rod is fixedly connected to the cover plate. Both the support rod and the reinforcing rib are located between the bent portion and the main body portion. Along the first direction, the support rod supports the first end, and the reinforcing rib is fixedly connected to the second end and supports the second end.

2. The battery cell according to claim 1, characterized in that, The cover plate includes a plate body and a lower plastic part connected to the plate body. Along the first direction, the lower plastic part is located between the plate body and the electrode assembly, and the support rod is detachably connected to the lower plastic part.

3. The battery cell according to claim 2, characterized in that, The lower plastic is provided with slots at both ends along the second direction. The support rod includes a rod body, a first slot and a second slot. The first slot and the second slot are respectively located at the ends of the rod body along the second direction. The first slot and the second slot are respectively embedded in the slots along the second direction.

4. The battery cell according to claim 3, characterized in that, The battery cell also includes a third direction that intersects the first direction and the second direction in pairs. Along the third direction, the size of the first card holder is L1mm and the size of the second card holder is L2mm, satisfying: L1>L2.

5. The battery cell according to claim 3, characterized in that, Along the first direction, the lower plastic is provided with a limiting groove on the side opposite to the plate body, and the support rod also includes a limiting plate. The limiting plate is connected between the rod body and the first card platform and between the rod body and the second card platform. The limiting plate is embedded in the limiting groove along the first direction.

6. The battery cell according to claim 4, characterized in that, Two electrode assemblies are arranged symmetrically about the second direction, and two support rods are arranged at intervals along the third direction. Each support rod corresponds to one of the electrode assemblies, and the reinforcing rib connects the two support rods.

7. The battery cell according to any one of claims 1-6, characterized in that, The cover plate is also provided with a pressure relief hole, and the bracket also includes a frame body arranged opposite to the pressure relief hole along the first direction. The support rod is fixedly connected to the frame body, and the frame body is provided with an air guide hole that penetrates the frame body along the first direction.

8. The battery cell according to claim 7, characterized in that, The cover plate is also provided with an injection hole, which penetrates the cover plate along the first direction. The bracket also includes a support plate and a baffle. The support plate is connected between the reinforcing rib and the frame. The baffle is located on the side of the support plate away from the cover plate along the first direction. The baffle and the support plate form a guide groove extending along the second direction. The guide groove connects the injection hole and the receiving cavity.

9. The battery cell according to claim 7, characterized in that, The air guide hole includes at least one of rectangular hole, circular hole or elliptical hole, and the air guide hole array is provided with multiple holes.

10. A battery pack, characterized in that, Includes the battery cell described in any one of claims 1-9.

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