Single battery and battery pack

Abstract

The invention discloses a single battery and a battery pack, and belongs to the technical field of batteries. The electrode assembly is arranged in the accommodating cavity; the cover plate assembly comprises a cover plate body, the cover plate body covers the opening, and a first assembly hole penetrating in the first direction is formed in the cover plate body; at least part of the pole penetrates through the first assembly hole, and the pole is provided with a second assembly hole penetrating in the first direction; the connecting piece comprises a body part and a connecting part, at least part of the body part is inserted into the second assembly hole and connected with the pole, the connecting part is arranged on the side, facing the electrode assembly, of the body part, and the connecting part is arranged around the periphery of the body part and connected with the body part; according to the invention, the body part is matched with the second assembly hole in an inserting manner, so that the relative positions of the pole and the connecting sheet are positioned, and the mutual displacement is limited, and therefore, the position precision between the pole and the connecting sheet is convenient to control.

Description

Technical Field

[0001] The present application belongs to the field of battery technology, and specifically relates to a single cell and a battery pack. Background Art

[0002] As lithium-ion battery technology becomes increasingly mature, lithium-ion batteries are widely used as power batteries in electric vehicles and energy storage fields. The requirements for the performance and safety of lithium-ion batteries are increasing. As an accessory in lithium-ion batteries, the lithium battery top cover firstly seals the internal and external environments by welding with the aluminum shell, and secondly connects the internal and external circuits to transmit the internal current of the battery to the outside through the pole, thus playing a guiding role.

[0003] In the prior art, the cover plate assembly is mainly composed of a pole, a cover plate body and a sealing ring. In order to stably output the internal current of the battery, an adapter is usually used to connect the pole and the lug. The adapter is generally installed by welding. During the welding process, the relative position accuracy of the adapter and the pole is difficult to control. Summary of the invention

[0004] Purpose of the invention: The embodiment of the present application provides a single cell battery, aiming to solve the current technical problem that the relative position accuracy of the adapter and the pole is difficult to control; another purpose of the present application is to provide a battery pack.

[0005] Technical solution: The single cell described in the embodiment of the present application includes:

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

[0007] An electrode assembly is disposed in the accommodating cavity;

[0008] A cover plate assembly, comprising a cover plate body, the cover plate body is covered on the opening, the cover plate body is provided with a first assembly hole penetrating along a first direction, and the first direction is a thickness direction of the cover plate body;

[0009] A pole, at least partly passing through the first assembly hole, the pole being provided with a second assembly hole passing through along the first direction;

[0010] A connecting piece includes a main body and a connecting part, wherein at least a portion of the main body is inserted into the second assembly hole and connected to the pole, and the connecting part is arranged on the side of the main body facing the electrode assembly, and the connecting part is arranged around the periphery of the main body and connected to the main body, and the connecting part is connected to the electrode assembly.

[0011] In some embodiments, the pole includes a plurality of inner side surfaces connected end to end, and the plurality of inner side surfaces surround and form the second assembly hole;

[0012] The main body portion 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 of the second surfaces is attached to one of the inner side surfaces and is formed with a first welding mark.

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

[0014] In some embodiments, the main body portion includes a first guide surface, the first guide surface is arranged around the outer circumference of the main body portion and is located at an end of the main body portion away from the connecting portion, and the first guide surface is arranged obliquely to the first direction;

[0015] The pole includes a second guide surface, which is arranged around the second assembly hole. The distance between the second guide surface and the connecting portion in the first direction gradually increases along the direction away from the connecting portion, and the second guide surface is configured to be able to fit with the first guide surface.

[0016] In some embodiments, the pole includes a first welding surface, the first welding surface is arranged around the outer circumference of the pole and opposite to the second assembly hole, the first welding surface is inclined to the first direction, and the distance between the first welding surface and the connecting portion in the first direction gradually increases along the direction away from the connecting portion;

[0017] The single cell further includes a welding block, which is disposed between the cover plate body and the connecting portion and around the first welding surface. The welding block includes a second welding surface, which is attached to the first welding surface and forms a second welding mark.

[0018] In some embodiments, an angle β between the first welding surface and the first direction satisfies: 5°≤β≤75°.

[0019] 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 battery.

[0020] In some embodiments, the pole includes a sealing surface, the sealing surface is arranged opposite to the cover body in the first direction, and the cover assembly further includes:

[0021] An upper plastic, at least partially disposed between the cover body and the sealing surface;

[0022] A sealing ring, sleeved on the pole, the sealing ring comprises a first sealing section and a second sealing section connected to each other, the first sealing section is arranged between the sealing surface and the cover body, and the second sealing section is passed through the first assembly hole;

[0023] The lower plastic is arranged between the cover body and the welding block, and the welding block is connected to the cover body through the lower plastic.

[0024] In some embodiments, the connecting portion is provided with an avoidance groove penetrating along the first direction.

[0025] Correspondingly, a battery pack described in an embodiment of the present application includes the above-mentioned single battery.

[0026] Beneficial effects: The single cell battery of the present application realizes the positioning of the relative positions of the pole and the connecting piece and limits the mutual displacement through the plug-in cooperation between the main body and the second assembly hole, so that the position accuracy between the pole and the connecting piece is easy to control, so as to increase the homogeneity of the single cell battery and improve the process yield; the connecting part is arranged on the periphery of the main body, which can increase the contact area between the pole and the electrode assembly and ensure the stable connection performance and conductivity between them; the pole is formed by one-time stamping, and its structure is simple. At the same time, the pole and the first assembly hole, the connecting piece and the second assembly hole can be pre-assembled by plugging, which is convenient and quick, and helps to improve the assembly efficiency.

[0027] The battery pack of the embodiment of the present application includes the above-mentioned single battery, and thus can have all the technical features and beneficial effects of the above-mentioned single battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0029] Figure 1 A cross-sectional view of a single cell provided in an embodiment of the present application;

[0030] Figure 2 A schematic diagram of the upper plastic, the sealing ring and the lower plastic provided in the embodiment of the present application;

[0031] Figure 3 A three-dimensional diagram of a pole and a connecting piece provided in an embodiment of the present application;

[0032] Figure 4 A schematic diagram of a second assembly hole provided in an embodiment of the present application;

[0033] Figure 5 A three-dimensional diagram of a connecting piece provided in an embodiment of the present application;

[0034] Figure 6 A schematic diagram of a body tank provided in an embodiment of the present application;

[0035] Figure 7 A cross-sectional view of a pole provided in an embodiment of the present application;

[0036] Figure 8 A cross-sectional view of a welding block provided in an embodiment of the present application;

[0037] Figure numerals: 1. Shell; 11. Accommodating cavity; 2. Electrode assembly; 3. Cover assembly; 31. Cover body; 311. First assembly hole; 32. Upper plastic; 33. Sealing ring; 331. First sealing section; 332. Second sealing section; 34. Lower plastic; 4. Pole; 41. Inner side surface; 42. Second assembly hole; 43. Second guide surface; 44. First welding surface; 45. Sealing surface; 5. Connecting piece; 51. Main body; 510. Main body groove; 511. First surface; 512. Second surface; 513. First guide surface; 52. Connecting part; 521. Avoidance groove; 6. First weld mark; 7. Welding block; 71. Second welding surface; 8. Second weld mark. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0039] In the description of the present application, it should be understood that the terms "height", "thickness", "up", "down", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In the description of the present application, "multiple" means two or more, and at least one means one, two or more, unless otherwise clearly and specifically defined. In the description of the present application, "vertical" means completely vertical at 90° or almost completely vertical, for example, an angle in the range of 85° to 95° is considered vertical.

[0040] It should also be noted that in the drawings of the embodiments of the present 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 describe the structure and relative position relationship of each component in the single cell. In actual applications, the first direction X and the second direction Y may change according to different placement methods of the single cells.

[0041] Please combine Figure 1 and Figure 2 The single cell of the embodiment of the present application comprises a shell 1, an electrode assembly 2, a cover assembly 3, a pole 4 and a connecting sheet 5. The shell 1 has a receiving cavity 11 and an opening connected to the receiving cavity 11 for placing some parts of the battery. The electrode assembly 2 is arranged in the receiving cavity 11. The electrode assembly 2 comprises a pole ear and a pole group, wherein the pole group comprises a diaphragm and at least two pole sheets, the diaphragm and at least two pole sheets are stacked and wound in a preset order, and the pole ear is connected to the pole sheet. The cover assembly 3 comprises a cover body 31, which is connected to the shell 1 and covers the opening. The cover body 31 is provided with a first assembly hole 311 penetrating along a first direction X, and the first direction X is the thickness direction of the cover body 31. The pole 4 is at least partially penetrated in the first assembly hole 311 and maintained in a relatively fixed state with the cover body 31. The pole 4 is provided with a second assembly hole 42 penetrating along the first direction X. The second assembly hole 42 can reduce the dead weight of the pole 4, and the pole 4 can also be processed and formed once by a stamping process, thereby simplifying the processing flow.

[0042] The connecting piece 5 includes a main body portion 51 and a connecting portion 52. At least a portion of the main body portion 51 is inserted into the second assembly hole 42 and connected to the pole 4. The connecting portion 52 is arranged on the side of the main body portion 51 facing the electrode assembly 2. The connecting portion 52 is arranged around the outer periphery of the main body portion 51 and is vertically connected to the main body portion 51. The connecting portion 52 is located outside the second assembly hole 42 at the positive projection edge of the cover body 31 along the first direction X, and the connecting portion 52 is located between the pole 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 pole ear, so that the pole ear can be electrically connected to the pole 4 through the connecting piece 5.

[0043] The pole 4 and the connecting piece 5 are positioned relative to each other through the plug-in cooperation between the main body 51 and the second assembly hole 42 to limit the relative displacement in the later welding process, thereby facilitating the control of the position accuracy of the pole 4 and the connecting piece 5, and is beneficial to improving the homogeneity of the single cells in the batch production process, thereby achieving the purpose of increasing the process yield.

[0044] In the present application, the number of the first assembly hole 311, the pole 4 and the connecting plate 5 are all set to two, each pole 4 corresponds to a first assembly hole 311, and one pole 4 is a positive pole, and the other pole 4 is a negative pole, each connecting plate 5 is connected to a pole 4, and accordingly, the electrode assembly 2 includes a positive pole ear and a negative pole ear, and the positive pole ear and the negative pole ear are respectively connected to a connecting portion 52.

[0045] Please combine Figure 3 , Figure 4 and Figure 5 In some embodiments, the pole 4 includes a plurality of inner side surfaces 41 connected end to end, the inner side surfaces 41 are parallel to the first direction X, and the plurality of inner side surfaces 41 surround and form a second assembly hole 42, so that the shape of the second assembly hole 42 is polygonal. The body 51 includes a first surface 511 and a plurality of second surfaces 512, the first surface 511 is opposite to the inner bottom wall of the shell 1, and the plurality of second surfaces 512 are arranged around the first surface 511 and connected to the first surface 511, and two adjacent second surfaces 512 are connected, and each second surface 512 is attached to an inner side surface 41 and formed with a first weld mark 6. The pole 4 and the body 51 can be welded by seam welding, so that a circle of first weld marks 6 is formed between the inner side surface 41 and the second side surface 512, and the gap between them is blocked, which plays a sealing function. The fitting arrangement of the first surface 511 and the inner side surface 41 limits the relative rotation between the pole 4 and the connecting piece 5, and further improves the relative position accuracy between the two.

[0046] Please combine Figure 2 and Figure 6 In some embodiments, a body groove 510 extending along the first direction X is provided on one side of the body portion 51 facing the electrode assembly 2. The body groove 510 reduces the solid part of the body portion 51, so that the weight of the body portion 51 is reduced, which is conducive to reducing the overall weight of the single battery; the body groove 510 provides a working space for welding the pole 4 and the connecting piece 5, and the wall thickness of the body portion 51 is thinned due to the provision of the body groove 510, so it is easier to achieve uniform heating and cooling during the welding process, which is conducive to improving the welding quality. At the same time, due to the fast heat conduction speed of the body portion 51, the thermal stress it is subjected to can be relatively small, which helps to reduce the occurrence of welding defects.

[0047] Please combine Figure 2 , Figure 5 and Figure 7 In some embodiments, the main body 51 includes a first guide surface 513, which is arranged around the outer periphery of the main body 51 and located at one end of the main body 51 away from the connecting portion 52, and the first guide surface 513 is arranged inclined to the first direction X.

[0048] The pole 4 includes a second guide surface 43, which is arranged around the second assembly hole 42 and is located at one end of the pole 4 close to 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, and the second guide surface 43 is configured to be able to fit with the first guide surface 513. When the body 51 is inserted into the second assembly hole 42, the first guide surface 513 fits with the second guide surface 43, which plays a guiding role for the body 51, so that the body 51 is centered in the second assembly hole 42 and inserted smoothly to avoid interference between the body 51 and the pole 4.

[0049] Furthermore, the first guide surface 513 is disposed between the first surface 511 and each second surface 512 , and the first guide surface 513 connects the first surface 511 and each second surface 512 . The first guide surface 513 can serve as a chamfered surface for transition between the first surface 511 and each second surface 512 .

[0050] Please combine Figure 2 , Figure 7 and Figure 8 In some embodiments, the pole 4 includes a first welding surface 44, which is located at one end of the pole 4 close to the connecting portion 52. The first welding surface 44 is arranged around the outer periphery of the pole 4 and is opposite to the second assembly hole 42. The first welding surface 44 is inclined to the first direction X, and the distance between the first welding surface 44 and the connecting portion 52 in the first direction X gradually increases along the direction away from the connecting portion 52.

[0051] The single cell also includes a welding block 7, which is arranged between the cover body 31 and the connecting portion 52. The welding block 7 is arranged around the first welding surface 44. The welding block 7 includes a second welding surface 71, which is attached to the first welding surface 44 and forms a second welding mark 8. The end of the pole 4 close to the connecting portion 52 is riveted to the welding block 7, and the two are extruded and deformed due to the riveting, thereby forming the first welding surface 44 and the second welding surface 71. The pole 4 and the welding block 7 are then welded by a seam welding process to form a circle of second welding marks 8, and the pole 4 and the welding block 7 are fixed; since the pole 4 and the welding block 7 have been pre-fixed by riveting, the relative position relationship between the two can be maintained during the subsequent welding process, so that the position accuracy is improved. As a riveted object with the pole 4, the welding block 7 provides support for the pole 4 to maintain the stability of the pole 4 structure.

[0052] Please refer to Figure 7In some embodiments, the angle between the first welding surface 44 and the first direction X is β, which satisfies: 5°≤β≤75°. Specifically, β can be any value among 5°, 20°, 35°, 50°, 65°, 75°, or a range between any two values. The angle β can also be understood as the angle of the riveting at the end of the pole 4. By limiting the riveting angle, the contact area between the pole 4 and the welding block 7 is controlled to increase the pressing force and improve the strength and stability of the riveting.

[0053] Please refer to Figure 7 In some embodiments, in the second direction Y, the length of the first welding surface 44 is W mm, satisfying: W ≥ 0.2, the second direction Y is the length direction of the single battery, the second direction Y is perpendicular to the first direction X, and specifically, W can be any value among 0.2, 0.3, 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 pole 4. A suitable riveting width can maintain good contact between the riveting block and the pole 4, reduce the risk of loosening or displacement, and thus maintain the stability of the pole 4 structure.

[0054] Please refer to Figure 2 In some embodiments, the pole 4 includes a sealing surface 45 , and the sealing surface 45 is arranged opposite to the cover body 31 in the first direction X. The cover assembly 3 also includes an upper plastic 32 , a sealing ring 33 and a lower plastic 34 .

[0055] The upper plastic 32 is arranged on the side of the cover body 31 away from the electrode assembly 2, and at least a portion of the upper plastic 32 is arranged between the cover body 31 and the sealing surface 45 to separate the sealing surface 45 from the surface of the cover body 31 facing away from the electrode assembly 2, so that the pole 4 is insulated from the cover body 31 at the end corresponding to the sealing surface 45.

[0056] The sealing ring 33 is sleeved on the pole 4, and the sealing ring 33 includes a first sealing section 331 and a second sealing section 332 which are connected. The first sealing section 331 is arranged between the sealing surface 45 and the cover body 31 to support the pole 4 and separate the sealing surface 45 from the cover body 31; the second sealing section 332 is passed through the first assembly hole 311 and connects the pole 4 and the cover body 31 to separate the pole 4 from the hole wall of the first assembly hole 311 to maintain mutual insulation.

[0057] The lower plastic 34 is disposed between the cover body 31 and the welding block 7, and the welding block 7 is connected to the cover body 31 through the lower plastic 34, so that the welding block 7 is separated from the cover body 31 to achieve mutual insulation. When the pole 4 is riveted to the welding block 7, the cover 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 assembly 3 and helps to improve the assembly efficiency.

[0058] Please combine Figure 4 and Figure 5 In some embodiments, the connecting portion 52 is provided with an avoidance groove 521 penetrating along the first direction X. The avoidance groove 521 is arranged corresponding to the injection hole on the cover body 31. When the electrolyte is injected into the shell 1 through the injection hole, the avoidance groove 521 can make the electrolyte fall smoothly to the electrode assembly 2, so that the electrolyte can fully infiltrate the electrode sheet in the electrode assembly 2.

[0059] Please refer to Figure 2 In some embodiments, the first weld mark 6 is disposed at an end of the second surface 512 away from the connecting portion 52. When welding the pole 4 and the body 51, the first weld mark 6 is located away from the upper plastic 32 and the lower plastic 34, which can reduce the influence of welding heat on the plastic part and ensure the insulation and sealing performance of the plastic part.

[0060] Correspondingly, a battery pack provided in an embodiment of the present application includes the single cell of the above embodiment, so the battery pack can have all the technical features and beneficial effects of the above single cell, which will not be repeated here.

[0061] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0062] The single cell and battery pack provided in the embodiments of the present application are introduced in detail above, and the principles and implementation methods of the present application are explained by using specific examples. The description of the above embodiments is only used to help understand the technical solution and its core idea of ​​the present application. Ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some of the technical features therein with equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A single cell battery, characterized in that: include: A housing having a receiving cavity and an opening communicating with the receiving cavity; An electrode assembly is disposed in the accommodating cavity; A cover plate assembly, comprising a cover plate body, the cover plate body is covered on the opening, the cover plate body is provided with a first assembly hole penetrating along a first direction, and the first direction is a thickness direction of the cover plate body; A pole, at least partly passing through the first assembly hole, the pole being provided with a second assembly hole passing through along the first direction; A connecting piece includes a main body and a connecting part, wherein at least a portion of the main body is inserted into the second assembly hole and connected to the pole, and the connecting part is arranged on the side of the main body facing the electrode assembly, and the connecting part is arranged around the periphery of the main body and connected to the main body, and the connecting part is connected to the electrode assembly.

2. The single cell according to claim 1, characterized in that: The pole comprises a plurality of inner side surfaces connected end to end, and the plurality of inner side surfaces surround and form the second assembly hole; The main body portion includes a first surface and a plurality of second surfaces, wherein the plurality of second surfaces are arranged around the first surface and connected to the first surface, and each of the second surfaces is attached to one of the inner side surfaces and is formed with a first welding mark.

3. The single cell according to claim 1, characterized in that: A body groove extending along the first direction is formed on a side of the body portion facing the electrode assembly.

4. The single cell according to claim 1, characterized in that: The main body portion comprises a first guide surface, the first guide surface is arranged around the outer circumference of the main body portion and is located at an end of the main body portion away from the connecting portion, and the first guide surface is arranged obliquely to the first direction; The pole includes a second guide surface, which is arranged around the second assembly hole. The distance between the second guide surface and the connecting portion in the first direction gradually increases along the direction away from the connecting portion, and the second guide surface is configured to be able to fit with the first guide surface.

5. The single cell according to claim 1, characterized in that: The pole comprises a first welding surface, the first welding surface is arranged around the outer circumference of the pole and opposite to the second assembly hole, the first welding surface is inclined to the first direction, and the distance between the first welding surface and the connecting portion in the first direction gradually increases along the direction away from the connecting portion; The single cell further includes a welding block, which is disposed between the cover plate body and the connecting portion and around the first welding surface. The welding block includes a second welding surface, which is attached to the first welding surface and forms a second welding mark.

6. The single cell according to claim 5, characterized in that: The included angle between the first welding surface and the first direction is β, which satisfies: 5°≤β≤75°.

7. The single cell according to claim 5, characterized in that: 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 battery.

8. The single cell according to claim 5, characterized in that: The pole comprises a sealing surface, and the sealing surface is arranged opposite to the cover plate body in the first direction. The cover plate assembly further comprises: An upper plastic, at least partially disposed between the cover body and the sealing surface; A sealing ring, sleeved on the pole, comprising a first sealing section and a second sealing section connected to each other, wherein the first sealing section is arranged between the sealing surface and the cover body, and the second sealing section is passed through the first assembly hole; The lower plastic is arranged between the cover body and the welding block, and the welding block is connected to the cover body through the lower plastic.

9. The single cell according to claim 1, characterized in that: The connecting portion is provided with an avoidance groove penetrating along the first direction.

10. A battery pack, characterized in that: A single cell as claimed in any one of claims 1 to 9.

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