Individual cells and battery packs

Abstract

This application discloses a single-cell battery and a battery pack, belonging to the field of battery technology. The single-cell battery of this application includes: a casing; an electrode assembly disposed in a receiving cavity; a cover plate assembly including a cover plate body covering the opening, the cover plate body having a first mounting hole extending in a first direction; an electrode post, at least partially disposed in the first mounting hole, the electrode post having a second mounting hole extending in the first direction; and a connecting piece including a body portion and a connecting portion, at least a portion of the body portion being inserted into the second mounting hole and connected to the electrode post, the connecting portion being disposed on the side of the body portion facing the electrode assembly, the connecting portion being disposed around the outer periphery of the body portion and connected to the body portion. This application achieves the positioning of the relative positions of the electrode post and the connecting piece through the insertion and cooperation of the body portion and the second mounting hole, and restricts the displacement between them, thereby making it easy to control the positional accuracy between the electrode post and the connecting piece.

Description

Technical Field

[0001] This application belongs to the field of battery technology, specifically relating to a single cell battery and a battery pack. Background Technology

[0002] With the increasing maturity of lithium-ion battery technology, lithium-ion batteries are widely used as power batteries in electric vehicles and energy storage. The requirements for the performance and safety of lithium-ion batteries are increasing. As an accessory of lithium-ion batteries, the top cover of the lithium battery firstly isolates the internal and external environments by welding it to the aluminum shell, thus playing a sealing role. Secondly, it connects the internal and external circuits, and transmits the internal current of the battery to the outside through the terminals, thus playing a current guiding role.

[0003] In the existing technology, the cover plate assembly is mainly composed of the terminal post, the cover plate body and the sealing ring. In order to stabilize the output of the battery internal current, an adapter plate is usually used to connect the terminal post and the tab. The adapter plate is generally installed by welding. During the welding process, it is difficult to control the relative position accuracy between the adapter plate and the terminal post. Summary of the Invention

[0004] Purpose of the invention: The embodiments of this application provide a single battery cell, which aims to solve the technical problem that the relative positional accuracy of the adapter and the terminal is difficult to control; another purpose of this application is to provide a battery pack.

[0005] Technical solution: The single-cell battery described in the embodiments of this application includes:

[0006] A housing having a receiving cavity and an opening communicating with the receiving cavity;

[0007] The electrode assembly is disposed within the receiving cavity;

[0008] A cover plate assembly includes a cover plate body, the cover plate body being disposed over the opening, and the cover plate body having a first mounting hole extending along a first direction, the first direction being the thickness direction of the cover plate body;

[0009] The pole post is at least partially inserted through the first mounting hole, and the pole post is provided with a second mounting hole that extends through the first direction;

[0010] A connecting piece includes a body portion and a connecting portion. At least a portion of the body portion is inserted into the second mounting hole and connected to the electrode post. The connecting portion is disposed on the side of the body portion facing the electrode assembly. The connecting portion is disposed around the outer periphery of the body portion and connected to the body portion. The connecting portion is connected to the electrode assembly.

[0011] The pole post includes multiple inner surfaces connected end to end, and the multiple inner surfaces surround to form the second assembly hole;

[0012] The main body includes a first surface and a plurality of second surfaces. The plurality of second surfaces are arranged around the first surface and connected to the first surface. Each second surface is attached to an inner surface and has a first solder mark formed thereon.

[0013] In some embodiments, the body portion is provided with a body groove extending along the first direction on the side facing the electrode assembly.

[0014] In some embodiments, the pole post includes a first welding surface, which is disposed around the outer periphery of the pole post and opposite to the second mounting hole. The first welding surface is inclined in the first direction, and the distance between the first welding surface and the connecting portion in the first direction gradually increases in the direction away from the connecting portion.

[0015] The single cell also includes a welding block, which is disposed between the cover plate body and the connecting part and surrounds the first welding surface. The welding block includes a second welding surface, which is attached to the first welding surface and has a second weld mark.

[0016] In some embodiments, the angle between the first welding surface and the first direction is β, satisfying: 5°≤β≤75°.

[0017] In some embodiments, in the second direction, the length of the first welding surface is W mm, satisfying: W≥0.2, and the second direction is the length direction of the single cell.

[0018] In some embodiments, the pole post includes a sealing surface, the sealing surface being disposed opposite to the cover plate body in the first direction, and the cover plate assembly further includes:

[0019] The plastic coating is at least partially disposed between the cover plate body and the sealing surface;

[0020] A sealing ring is fitted onto the pole post. The sealing ring includes a first sealing section and a second sealing section connected together. The first sealing section is disposed between the sealing surface and the cover plate body, and the second sealing section passes through the first assembly hole.

[0021] A lower plastic layer is disposed between the cover plate body and the welding block, and the welding block is connected to the cover plate body through the lower plastic layer.

[0022] In some embodiments, the connecting portion is provided with a clearance groove extending through the first direction.

[0023] Accordingly, the battery pack described in this application embodiment includes the aforementioned single battery cell.

[0024] Beneficial effects: The single cell of this application achieves the positioning of the relative positions of the electrode post and the connecting piece through the insertion and cooperation of the body part and the second mounting hole, and restricts the displacement between them. This makes it easier to control the positional accuracy between the electrode post and the connecting piece, thereby increasing the homogeneity of the single cell and improving the process yield. The connecting part is located on the outer periphery of the body part, which can increase the contact area between the electrode post and the electrode assembly, ensuring stable connection performance and conductivity between them. The electrode post is formed by one-time stamping, which has a simple structure. At the same time, the electrode post and the first mounting hole, and the connecting piece and the second mounting hole can be pre-assembled by insertion, which is convenient and quick and helps to improve assembly efficiency.

[0025] The battery pack of this application embodiment includes the above-described single battery cell, and therefore can have all the technical features and beneficial effects of the above-described single battery cell. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 A cross-sectional view of a single battery cell provided in an embodiment of this application;

[0028] Figure 2 A schematic diagram of the upper plastic, sealing ring, and lower plastic provided in an embodiment of this application;

[0029] Figure 3 A perspective view of the pole post and connecting piece provided in the embodiments of this application;

[0030] Figure 4 A schematic diagram of the second assembly hole provided in an embodiment of this application;

[0031] Figure 5 A perspective view of the connecting piece provided in the embodiments of this application;

[0032] Figure 6 A schematic diagram of the body groove provided in an embodiment of this application;

[0033] Figure 7 A cross-sectional view of the pole provided in an embodiment of this application;

[0034] Figure 8 A cross-sectional view of the welding block provided in an embodiment of this application;

[0035] Reference numerals: 1. Housing; 11. Receiving cavity; 2. Electrode assembly; 3. Cover plate assembly; 31. Cover plate body; 311. First mounting hole; 32. Upper plastic; 33. Sealing ring; 331. First sealing section; 332. Second sealing section; 34. Lower plastic; 4. Electrode post; 41. Inner side; 42. Second mounting hole; 43. Second guide surface; 44. First welding surface; 45. Sealing surface; 5. Connecting piece; 51. Body part; 510. Body groove; 511. First surface; 512. Second surface; 513. First guide surface; 52. Connecting part; 521. Clearance groove; 6. First weld mark; 7. Welding block; 71. Second welding surface; 8. Second weld mark. Detailed Implementation

[0036] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0037] In the description of this application, it should be understood that the terms "height," "thickness," "upper," "lower," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. In the description of this application, "a plurality of" means two or more, and at least one can mean one, two, or more, unless otherwise explicitly specified. In the description of this application, "vertical" means completely perpendicular to 90° or almost completely perpendicular, for example, an angle within the range of 85° to 95° is considered vertical.

[0038] It should also be noted that in the accompanying drawings of the embodiments of this application, the arrow marked with X represents the first direction X, and the arrow marked with Y represents the second direction Y. The first direction X and the second direction Y are introduced to more clearly illustrate the structure and relative positional relationship of each component in the single battery cell. In practical applications, the first direction X and the second direction Y may change depending on the arrangement of the single battery cell.

[0039] Please combine them together Figure 1 and Figure 2The single-cell battery of this application embodiment includes a housing 1, an electrode assembly 2, a cover plate assembly 3, a terminal post 4, and a connecting piece 5. The housing 1 has a receiving cavity 11 and an opening communicating with the receiving cavity 11 for inserting some battery components. The electrode assembly 2 is disposed in the receiving cavity 11 and includes a tab and an electrode group, wherein the electrode group includes a separator and at least two electrode sheets. The separator and at least two electrode sheets are stacked and wound in a preset order, and the tab is connected to the electrode sheets. The cover plate assembly 3 includes a cover plate body 31, which is connected to the housing 1 and seals the opening. The cover plate body 31 is provided with a first mounting hole 311 extending along a first direction X, where the first direction X is the thickness direction of the cover plate body 31. The terminal post 4 is at least partially inserted through the first mounting hole 311 and is kept relatively fixed to the cover plate body 31. The terminal post 4 is provided with a second mounting hole 42 extending along the first direction X. The second mounting hole 42 can reduce the weight of the terminal post 4 and can also be formed in one step by a stamping process, simplifying the processing flow.

[0040] The connecting piece 5 includes a body portion 51 and a connecting portion 52. At least a portion of the body portion 51 is inserted into the second mounting hole 42 and connected to the electrode post 4. The connecting portion 52 is disposed on the side of the body portion 51 facing the electrode assembly 2. The connecting portion 52 is disposed around the outer periphery of the body portion 51 and is perpendicularly connected to the body portion 51. The edge of the projection of the connecting portion 52 along the first direction X on the cover plate body 31 is located outside the second mounting hole 42. The connecting portion 52 is located between the electrode post 4 and the electrode assembly 2. The connecting portion 52 is connected to the electrode assembly 2. Specifically, the connecting portion 52 is connected to the electrode tab, so that the electrode tab can be electrically connected to the electrode post 4 through the connecting piece 5.

[0041] The electrode post 4 and the connecting piece 5 are positioned relative to each other by the insertion and engagement of the body part 51 and the second assembly hole 42, so as to limit the relative displacement during the subsequent welding process. This facilitates the control of the positional accuracy of the electrode post 4 and the connecting piece 5, which helps to improve the homogeneity of single cells in batch production and thus achieves the goal of increasing the process yield.

[0042] In this application, the number of the first mounting hole 311, the pole post 4 and the connecting piece 5 are all set to two. Each pole post 4 corresponds to one first mounting hole 311, and one pole post 4 is the positive pole and the other pole post 4 is the negative pole. Each connecting piece 5 is connected to one pole post 4. Correspondingly, the electrode assembly 2 includes a positive electrode tab and a negative electrode tab, and the positive electrode tab and the negative electrode tab are respectively connected to a connecting part 52.

[0043] Please combine them together Figure 3 , Figure 4 and Figure 5In some embodiments, the pole post 4 includes multiple inner side surfaces 41 connected end to end, the inner side surfaces 41 being parallel to the first direction X. The multiple inner side surfaces 41 surround to form a second mounting hole 42, making the shape of the second mounting hole 42 polygonal. The body part 51 includes a first surface 511 and multiple second surfaces 512. The first surface 511 faces away from the inner bottom wall of the housing 1. The multiple second surfaces 512 are arranged around the first surface 511 and connected to the first surface 511. Adjacent two second surfaces 512 are connected. Each second surface 512 is attached to an inner side surface 41 and forms a first weld mark 6. The pole post 4 and the body part 51 can be welded using a seam welding process, thereby forming a ring of first weld marks 6 between the inner side surface 41 and the second surface 512, sealing the gaps between them and achieving a sealing function. The fitted arrangement of the first surface 511 and the inner side surface 41 restricts the relative rotation between the pole post 4 and the connecting piece 5, further improving the relative positional accuracy of the two.

[0044] Please combine them together Figure 2 and Figure 6 In some embodiments, the body portion 51 has a body groove 510 extending along the first direction X on the side facing the electrode assembly 2. The body groove 510 reduces the solid portion of the body portion 51, thereby reducing the weight of the body portion 51 and helping to reduce the overall weight of the single cell. The body groove 510 provides working space for welding the electrode post 4 and the connecting piece 5. With the wall thickness of the body portion 51 reduced due to the body groove 510, it is easier to achieve uniform heating and cooling during the welding process, which is beneficial to improving the welding quality. At the same time, because the heat conduction speed of the body portion 51 is fast, the thermal stress it is subjected to is relatively small, which helps to reduce the generation of welding defects.

[0045] Please combine them together Figure 2 , Figure 5 and Figure 7 In some embodiments, the body portion 51 includes a first guide surface 513, which is disposed around the outer periphery of the body portion 51 and located at the end of the body portion 51 away from the connecting portion 52. The first guide surface 513 is disposed inclined in a first direction X.

[0046] The pole post 4 includes a second guide surface 43, which surrounds the second mounting hole 42 and is located at the end of the pole post 4 near the connecting portion 52. The distance between the second guide surface 43 and the connecting portion 52 in the first direction X gradually increases in the direction away from the connecting portion 52. The second guide surface 43 is configured to fit against the first guide surface 513. When the body portion 51 is inserted into the second mounting hole 42, the first guide surface 513 fits against the second guide surface 43, which guides the body portion 51, allowing it to be aligned with the second mounting hole 42 and inserted smoothly, thus preventing interference between the body portion 51 and the pole post 4.

[0047] Furthermore, a first guide surface 513 is disposed between the first surface 511 and each of the second surfaces 512. The first guide surface 513 connects the first surface 511 and each of the second surfaces 512. The first guide surface 513 can serve as a chamfered surface for the transition between the first surface 511 and each of the second surfaces 512.

[0048] Please combine them together Figure 2 , Figure 7 and Figure 8 In some embodiments, the pole post 4 includes a first welding surface 44, which is located at one end of the pole post 4 near the connecting portion 52. The first welding surface 44 is disposed around the outer periphery of the pole post 4 and is opposite to the second mounting hole 42. The first welding surface 44 is inclined in a first direction X. The distance between the first welding surface 44 and the connecting portion 52 in the first direction X gradually increases in the direction away from the connecting portion 52.

[0049] The single-cell battery also includes a welding block 7, which is disposed between the cover plate body 31 and the connecting part 52. The welding block 7 is arranged around the first welding surface 44 and includes a second welding surface 71. The second welding surface 71 is attached to the first welding surface 44 and forms a second weld mark 8. The end of the terminal post 4 near the connecting part 52 is riveted to the welding block 7. Due to the riveting, the two are squeezed and deformed, thus forming the first welding surface 44 and the second welding surface 71. Then, the terminal post 4 and the welding block 7 are welded by a seam welding process to form a ring of second weld marks 8, fixing the terminal post 4 and the welding block 7. Since the terminal post 4 and the welding block 7 have been pre-fixed by riveting, the relative positional relationship between the two can be maintained during the subsequent welding process, thereby improving the positional accuracy. As the object to be riveted to the terminal post 4, the welding block 7 provides support for the terminal post 4 to maintain the stability of the terminal post 4 structure.

[0050] Please refer to Figure 7 In some embodiments, the angle between the first welding surface 44 and the first direction X is β, satisfying: 5°≤β≤75°. Specifically, β can be any value among 5°, 20°, 35°, 50°, 65°, and 75°, or a range between any two values. The included angle β can also be understood as the riveting angle at the end of the pole post 4. By limiting the riveting angle, the contact area between the pole post 4 and the welding block 7 is controlled to increase the pressing force and improve the strength and stability of the riveting.

[0051] Please refer to Figure 7In some embodiments, the length of the first welding surface 44 in the second direction Y is W mm, satisfying: W ≥ 0.2. The second direction Y is the length direction of the single cell, and the second direction Y is perpendicular to the first direction X. Specifically, W can be any value among 0.2, 0.3, and 0.4, or a range between any two values. The welding length W can be understood as the width of the riveting at the end of the electrode post 4. A suitable riveting width can ensure good contact between the riveting block and the electrode post 4, reducing the risk of loosening or displacement, thereby maintaining the stability of the electrode post 4 structure.

[0052] Please refer to Figure 2 In some embodiments, the pole post 4 includes a sealing surface 45, which is disposed opposite to the cover plate body 31 in the first direction X. The cover plate assembly 3 also includes an upper plastic 32, a sealing ring 33, and a lower plastic 34.

[0053] The upper plastic 32 is disposed on the side of the cover plate body 31 away from the electrode assembly 2. At least a portion of the upper plastic 32 is disposed between the cover plate body 31 and the sealing surface 45 to separate the sealing surface 45 from the surface of the cover plate body 31 away from the electrode assembly 2, so that the pole post 4 is insulated from the cover plate body 31 at the end corresponding to the sealing surface 45.

[0054] A sealing ring 33 is fitted onto the pole post 4. The sealing ring 33 includes a first sealing section 331 and a second sealing section 332 connected together. The first sealing section 331 is disposed between the sealing surface 45 and the cover plate body 31 to support the pole post 4 and space the sealing surface 45 and the cover plate body 31. The second sealing section 332 passes through the first assembly hole 311 and connects the pole post 4 and the cover plate body 31 so that the pole post 4 is spaced apart from the hole wall of the first assembly hole 311 and maintains mutual insulation.

[0055] The lower plastic 34 is disposed between the cover plate body 31 and the welding block 7. The welding block 7 is connected to the cover plate body 31 through the lower plastic 34, thereby separating the welding block 7 from the cover plate body 31 and achieving mutual insulation. When the pole post 4 is riveted to the welding block 7, the cover plate body 31, the lower plastic 34, and the welding block 7 are fixedly connected, which facilitates the assembly of the various components of the cover plate assembly 3 and helps to improve assembly efficiency.

[0056] Please combine them together Figure 4 and Figure 5 In some embodiments, the connecting part 52 is provided with a relief groove 521 that extends through the first direction X. The relief groove 521 is corresponding to the liquid injection hole on the cover plate body 31. When electrolyte is injected into the housing 1 through the liquid injection hole, the relief groove 521 can allow the electrolyte to fall smoothly into the electrode assembly 2, so that the electrolyte can fully wet the electrode in the electrode assembly 2.

[0057] Please refer to Figure 2In some embodiments, the first solder mark 6 is located at the end of the second surface 512 away from the connecting portion 52. When welding the pole post 4 and the body portion 51, the position of the first solder mark 6 away from the upper plastic 32 and the lower plastic 34 can reduce the impact of welding heat on the plastic parts and ensure the insulation and sealing performance of the plastic parts.

[0058] Accordingly, the battery pack provided in this application includes the single cell of the above embodiment. Therefore, the battery pack can have all the technical features and beneficial effects of the single cell, which will not be repeated here.

[0059] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0060] The single-cell battery and battery pack provided in the embodiments of this application have been described in detail above, and specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the technical solutions and core ideas of this application. Those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A single cell, characterized by, The application relates to a battery cover plate assembly, comprising: a housing having a receiving cavity and an opening communicating with the receiving cavity; an electrode assembly arranged in the receiving cavity; a cover plate assembly comprising a cover plate body, the cover plate body being arranged on the opening, the cover plate body being provided with a first assembly hole penetrating in a first direction, the first direction being the thickness direction of the cover plate body; a pole column at least partially penetrating the first assembly hole, the pole column being provided with a second assembly hole penetrating in the first direction; the pole column comprising a first welding surface, the first welding surface being arranged around the outer periphery of the pole column and opposite to the second assembly hole, the first welding surface being inclined to the first direction; a connecting piece comprising a body part and a connecting part, at least part of the body part being inserted into the second assembly hole and connected with the pole column, a body groove extending in the first direction being formed on the side of the body part facing the electrode assembly; the connecting part being arranged on the side of the body part facing the electrode assembly, the connecting part being arranged around the outer periphery of the body part and connected with the body part, the connecting part being connected with the electrode assembly; the distance between the first welding surface and the connecting part in the first direction gradually increases away from the connecting part; a welding block being arranged between the cover plate body and the connecting part and around the first welding surface, the welding block comprising a second welding surface, the second welding surface being arranged on the first welding surface and formed with a second welding mark; the included angle between the first welding surface and the first direction is beta, and 5 DEG <= beta <= 75 DEG.

2. The cell according to claim 1, wherein The pole column comprises a plurality of inner side surfaces connected head to tail, and the plurality of inner side surfaces surround the second assembly hole; The body part comprises a first surface and a plurality of second surfaces, the plurality of second surfaces being arranged around the first surface and connected with the first surface, each second surface being arranged on one inner side surface and formed with a first welding mark.

3. The cell according to claim 1, wherein The body part comprises a first guide surface, the first guide surface being arranged around the outer periphery of the body part and located at the end of the body part away from the connecting part, the first guide surface being arranged obliquely to the first direction; The pole column comprises a second guide surface, the second guide surface being arranged around the second assembly hole, the distance between the second guide surface and the connecting part in the first direction gradually increases away from the connecting part, and the second guide surface is configured to be capable of being fitted with the first guide surface.

4. The cell according to claim 1, wherein In a second direction, the length of the first welding surface is W mm, and W >= 0.2, the second direction being the length direction of the single battery.

5. The cell according to claim 1, wherein The pole column comprises a sealing surface, the sealing surface being arranged opposite to the cover plate body in the first direction, and the cover plate assembly further comprises: an upper plastic being at least partially arranged between the cover plate body and the sealing surface; a sealing ring being sleeved on the pole column and comprising a first sealing section and a second sealing section connected with each other, the first sealing section being arranged between the sealing surface and the cover plate body, and the second sealing section penetrating the first assembly hole. A lower plastic is arranged between the cover plate body and the welding block, and the welding block is connected with the cover plate body through the lower plastic.

6. The cell according to claim 1, wherein The connecting portion is provided with an avoiding slot penetrating along the first direction.

7. A battery pack, characterized by, The single cell according to any one of claims 1 to 6.

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