Single battery and battery pack

Abstract

The utility model discloses a single battery and a battery pack, and belongs to the technical field of batteries. The single battery comprises a cover plate assembly and an electrode assembly which are connected, the cover plate assembly has a thickness direction, and the electrode assembly is arranged on one side of the cover plate assembly in the thickness direction; the cover plate assembly comprises a cover plate body, a pole and a sealing plate, an assembly hole is formed in the cover plate body in the thickness direction; the pole penetrates through the assembly hole, and a first through hole is formed in the pole in the thickness direction; the sealing plate covers the first hole and is connected with the pole; the electrode assembly comprises a tab, and the tab penetrates into the first hole and is connected with the sealing plate. The pole is provided with a penetrating type opening structure, the first hole formed in the pole is covered and sealed by the sealing plate, and the sealing plate is electrically connected with the tab, so that a connecting sheet is omitted, the internal resistance of the single battery is reduced, welding procedures and parts are reduced, the cost is reduced, and the assembly efficiency is improved.

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] A single cell includes a casing, an electrode assembly, and a cover assembly. The cover assembly is used to seal the casing and supports the terminal posts.

[0003] However, the existing cover plate assembly has a large number of parts. Utility Model Content

[0004] The purpose of this utility model is to provide a single battery cell to overcome the technical problem of the large number of parts in the current cover plate assembly; another purpose of this application is to provide a battery pack.

[0005] Technical solution: The single cell disclosed in this application includes: a cover plate assembly and an electrode assembly, wherein the electrode assembly is disposed on one side of the cover plate assembly in its thickness direction;

[0006] The cover plate assembly includes:

[0007] The cover plate body has assembly holes along the thickness direction;

[0008] A pole post is inserted through the assembly hole, and the pole post has a through hole along the thickness direction;

[0009] A sealing plate is used to cover the first hole and connect to the pole post;

[0010] The electrode assembly includes a tab that passes through the first hole and is connected to the sealing plate.

[0011] In some embodiments, the pole post includes a main body, a first connecting part, and a second connecting part. The main body passes through the assembly hole. The first connecting part is disposed on one side of the cover plate body along the thickness direction and surrounds the main body. The second connecting part is disposed at one end of the main body away from the first connecting part along the thickness direction. The second connecting part is connected to the main body and forms a limiting groove.

[0012] The first hole penetrates the main body and the second connecting portion along the thickness direction;

[0013] The cover plate assembly further includes a connecting block, which is disposed on the side of the cover plate body away from the first connecting part and is partially embedded in the limiting groove;

[0014] The cover plate body is sandwiched between the first connecting part and the connecting block.

[0015] In some embodiments, the pole post includes a boss connected to the side of the first connecting portion away from the cover plate body, the boss and the first connecting portion forming a first recessed groove, the first recessed groove communicating with the first hole;

[0016] The sealing plate is provided with the first groove and the first hole along the thickness direction.

[0017] In some embodiments, the sealing plate has a first wall facing the boss, the boss has a second wall, and the first wall and the second wall are disposed opposite to each other.

[0018] Along the thickness direction, the sealing plate has a portion that protrudes outside the first settling groove;

[0019] The cover plate assembly further includes a first welded portion, which connects the first wall and the second wall respectively.

[0020] In some embodiments, the connecting block includes a first protrusion, which protrudes from the side of the connecting block facing the second connecting portion and engages with the limiting groove. The first protrusion has a first stepped surface, which is located on the side of the first protrusion away from the cover plate body.

[0021] The limiting groove has a second stepped surface, which is disposed opposite to the first stepped surface so that the second stepped surface can abut against the first stepped surface.

[0022] In some embodiments, the second step surface has an angle α with the thickness direction, satisfying 15°≤a≤75°.

[0023] In some embodiments, the connecting block includes a second protrusion, which protrudes from the side of the connecting block away from the cover plate body, and along the thickness direction, the second protrusion has a portion that protrudes beyond the first protrusion;

[0024] The cover plate assembly further includes a second welding part, which connects the first step surface and the second step surface respectively.

[0025] In some embodiments, the cover plate assembly further includes a sealing ring, the sealing ring including a first sealing segment, a second sealing segment and a third sealing segment, the first sealing segment being disposed between the main body and the cover plate body, the second sealing segment being sandwiched between the cover plate body and the connecting block, and the third sealing segment being embedded in the limiting groove and sandwiched between the main body and the connecting block, the first sealing segment connecting the second sealing segment and the third sealing segment respectively.

[0026] In some embodiments, a second recess is provided on the side of the cover plate body facing the connecting block, and the second recess communicates with the assembly hole and the limiting groove;

[0027] The second sink has a third wall facing the connecting block, and the limiting groove has a fourth wall facing the connecting block. The third wall and the fourth wall are on the same plane perpendicular to the thickness direction.

[0028] This application also discloses a battery pack, including the single battery cells as described in the above embodiments.

[0029] Beneficial Effects: The single-cell battery of this application embodiment includes a cover plate assembly and an electrode assembly. The cover plate assembly has a thickness direction, and the electrode assembly is disposed on one side of the cover plate assembly along the thickness direction. The cover plate assembly includes a cover plate body, an electrode post, and a sealing plate. The cover plate body has an assembly hole along the thickness direction. The electrode post passes through the assembly hole and has a through first hole along the thickness direction. The sealing plate covers the first hole and connects to the electrode post. The electrode assembly includes a tab, which passes through the first hole and connects to the sealing plate. The electrode post has a through-hole structure. By sealing the hole on the electrode post with the sealing plate, and simultaneously electrically connecting the tab, the connecting piece is eliminated, reducing the internal resistance of the single-cell battery, reducing welding processes and components, reducing costs, and improving assembly efficiency.

[0030] The battery pack of this application embodiment includes the single battery cell as described in the above embodiments. Therefore, it can have all the technical features and effects of the single battery cell described above, which will not be repeated here. Attached Figure Description

[0031] 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.

[0032] Figure 1 This is a three-dimensional structural diagram of a single battery cell according to an embodiment of this application;

[0033] Figure 2 This is a top view of the structure of a single battery cell according to an embodiment of this application;

[0034] Figure 3 This is a three-dimensional structural diagram of the cover plate assembly in a single battery cell according to an embodiment of this application, and the sealing plate is not shown in the figure;

[0035] Figure 4 for Figure 3 A structural diagram from a top-down view;

[0036] Figure 5 for Figure 2 Schematic cross-sectional view along the AA direction;

[0037] Figure 6 for Figure 5 A magnified view of a portion of point C in the middle;

[0038] Figure 7 for Figure 4 Cross-sectional view along the BB direction;

[0039] Figure 8 for Figure 7 Cross-sectional view of the central pole;

[0040] Figure 9 for Figure 5 Cross-sectional view of the middle sealing plate;

[0041] Figure 10 for Figure 7 Cross-sectional view of the connecting block;

[0042] Figure 11 for Figure 7 Cross-sectional view of the central sealing ring;

[0043] Explanation of reference numerals in the attached drawings: 1. Cover plate assembly; 2. Electrode assembly; X, thickness direction; 11. Cover plate body; 110. Assembly hole; 12. Electrode post; 120. First hole; 13. Sealing plate; 21. Electrode lug; 121. Main body; 122. First connecting part; 123. Second connecting part; 124. Limiting groove; 14. Connecting block; 125. Boss; 126. First recess; 131. First wall; 1251. Second wall; 15. First welded part; 141. First protrusion; 1411. First stepped surface; 1241. Second stepped surface; 142. Second protrusion; 16. Second welded part; 17. Sealing ring; 171. First sealing section; 172. Second sealing section; 173. Third sealing section; 111. Second recess; 1110. Third wall; 1240. Fourth wall. Detailed Implementation

[0044] 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.

[0045] In the description of this application, it should be understood that the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or component 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, "multiple" means two or more, and "at least one" can refer to one, two, or more, unless otherwise explicitly specified. The terms "first," "second," and "third," etc., are only for the convenience of description and are used to name parts or embodiments by number, and do not imply any order of importance between the parts or embodiments.

[0046] It should also be noted that in the accompanying drawings of this application, the arrow marked X is used to indicate the thickness direction X. In the description of this application, the thickness direction X is introduced to more clearly define the structure and relative positional relationship of each component in the single cell and the battery pack.

[0047] As a preamble to the embodiments of this application, the cover assembly 1 in the battery is mainly composed of an electrode post 12, a cover body 11, a connecting piece, and a sealing ring 17. However, the ear of the electrode assembly 2 and the electrode post 12 of the cover assembly 1 need to be connected by a connecting piece, which involves a large number of parts and a complex assembly process; at the same time, the electrode post 12 itself has a complex structure and cannot be formed in one go, requiring secondary processing, which results in high costs.

[0048] In view of this, embodiments of this application provide a single-cell battery, which aims to solve at least one of the above-mentioned technical problems.

[0049] Please see Figures 1 to 11 As shown, the single-cell battery of this application embodiment includes: a cover plate assembly 1 and an electrode assembly 2. The cover plate assembly 1 has a thickness direction X, and the electrode assembly 2 is disposed on one side of the cover plate assembly 1 in the thickness direction X. It should be understood that the single-cell battery also includes a housing, which has a receiving cavity and an opening. The cover plate assembly 1 is used to cover the opening and seal the electrode assembly 2 in the receiving cavity, thereby playing a protective role. At the same time, the cover plate assembly 1 is also used to realize the current of the electrode assembly 2 inside the housing to the outside of the housing.

[0050] The cover plate assembly 1 includes: a cover plate body 11, an electrode post 12, and a sealing plate 13; wherein, the cover plate body 11 can be a plain aluminum plate, and an assembly hole 110 is provided along the thickness direction X; the electrode post 12 passes through the assembly hole 110, and the electrode post 12 has a through hole 120 along the thickness direction X; the sealing plate 13 covers the first hole 120 and connects to the electrode post 12; the electrode assembly 2 includes an electrode tab 21, which passes through the first hole 120 and connects to the sealing plate 13. It should be understood that the electrode assembly 2 includes a connected electrode body and a tab 21; the electrode post 12 of this application has a through-hole structure, which can be processed in one step, resulting in low processing cost and reduced product weight; the first hole 120 can communicate with the receiving cavity, and the tab 21 of the electrode assembly 2 can pass through the first hole 120 and be directly connected to the sealing plate 13. The sealing plate 13 covers the first hole 120 and connects to the electrode post 12, achieving a seal between the sealing plate 13 and the electrode post 12, ensuring the environmental safety of the electrode assembly 2. By welding a busbar to the side of the sealing plate 13 away from the tab 21, the current inside the single cell can be led out to the outside, shortening the current flow path, reducing the internal resistance of the battery, and improving product performance. The above-mentioned cover plate assembly 1 structure eliminates the connecting piece, reduces the internal resistance of the single cell, and reduces the number of welding processes and parts, thereby improving assembly efficiency, reducing costs, and enhancing product competitiveness.

[0051] Please see Figure 5 and Figure 6 As shown, in some embodiments, the pole post 12 includes a main body 121, a first connecting part 122, and a second connecting part 123. The main body 121 passes through the assembly hole 110. The first connecting part 122 is disposed on one side of the cover plate body 11 along the thickness direction X and surrounds and connects to the main body 121. The second connecting part 123 is disposed at one end of the main body 121 along the thickness direction X away from the first connecting part 122. The second connecting part 123 is connected to the main body 121 and forms a limiting groove 124. The first hole 120 passes through the main body 121 and the second connecting part 123 along the thickness direction X. The cover plate assembly 1 also includes a connecting block 14, which is disposed on the side of the cover plate body 11 away from the first connecting part 122 and is partially embedded in the limiting groove 124. The cover plate body 11 is sandwiched between the first connecting part 122 and the connecting block 14.

[0052] It should be understood that the main body 121 and the second connecting part 123 form a limiting groove 124. A connecting block 14 is embedded in the limiting groove 124, thereby cooperating with the first connecting part 122 to clamp and fix both sides of the cover plate body 11. The connecting block 14 limits the lower side of the cover plate body 11, while the first connecting part 122 limits the upper side of the cover plate body 11. The main body 121 supports and connects the first connecting part 122 and the connecting block 14. More specifically, to ensure the sealing of the connection between the pole post 12 and the cover plate body 11, a sealing ring 17 and an upper plastic layer can be installed to ensure the sealing and insulation of the pole post 12 and the cover plate body 11. Specifically, the upper plastic layer is disposed between the first connecting part 122 and the cover plate body 11, and supports the connection between the first connecting part 122 and the cover plate body 11.

[0053] In some embodiments, the second connecting portion 123 may be a feature formed by thinning the main body portion 121. During the assembly of the pole post 12, the first hole 120 is opened through the pole post 12 along the thickness direction X, and an external stamping device is inserted into the first hole 120. The second connecting portion 123 and the main body portion 121 are formed into a limiting groove 124 by outward extrusion, so as to limit and fix the connecting block 14 below the cover plate body 11, thereby realizing the riveting fit between the pole post 12 and the connecting block 14. The pole post 12 of this application has a simple structure, and the connection strength between the pole post 12 and the cover plate body 11 is high and the stability is good. The assembly process is simple, without complicated assembly procedures, saving time and efficiency, and reducing costs.

[0054] Please see Figure 5 , Figure 6 and Figure 8 As shown, in some embodiments, the pole post 12 includes a boss 125, which is connected to the side of the first connecting portion 122 away from the cover plate body 11. The boss 125 and the first connecting portion 122 form a first recess 126, which communicates with the first hole 120. The sealing plate 13 passes through the first recess 126 and the first hole 120 along the thickness direction X. It should be understood that the boss 125 mainly plays a limiting role for the sealing plate 13 in the direction perpendicular to the thickness direction X; the first recess 126 and the first hole 120 serve to accommodate the sealing plate 13. At the same time, the first recess 126 communicates with the first hole 120, and the inner diameter of the first recess 126 is larger than the inner diameter of the first hole 120, so that the contact surface of the first recess 126 and the first hole 120 forms an assembly step for supporting the sealing plate 13. This assembly structure has high stability and facilitates the sealing welding of the sealing plate 13 and the pole post 12, ensuring sealing reliability.

[0055] Please see Figure 6 , Figure 8 and Figure 9As shown, in some embodiments, the sealing plate 13 has a first wall 131 facing the boss 125, the boss 125 has a second wall 1251, and the first wall 131 and the second wall 1251 are disposed opposite to each other; along the thickness direction X, the sealing plate 13 has a portion protruding outside the first recess 126; the cover plate assembly 1 further includes a first welding portion 15, which connects the first wall 131 and the second wall 1251 respectively. By welding the first wall 131 and the second wall 1251 through the first welding portion 15, the sealing plate 13 and the boss 125 are sealed together to ensure the sealing performance of the pole post 12. In some embodiments, the sealing plate 13 has a portion protruding outside the first recess 126 along the thickness direction X. It should be understood that the portion of the sealing plate 13 that protrudes outside the first sink 126 can protect the weld formed between the first wall 131 and the second wall 1251, preventing the weld from protruding from the sealing plate 13 and affecting the welding between the sealing plate 13 and the busbar. At the same time, it can prevent the weld from interfering with the outside, affecting the welding life and welding strength.

[0056] Please see Figure 6 , Figure 8 and Figure 10 As shown, in some embodiments, the connecting block 14 includes a first protrusion 141, which protrudes from the side of the connecting block 14 facing the second connecting portion 123 and engages with the limiting groove 124. The first protrusion 141 has a first stepped surface 1411, which is located on the side of the first protrusion 141 away from the cover plate body 11. The limiting groove 124 has a second stepped surface 1241, which is disposed opposite to the first stepped surface 1411 so that the second stepped surface 1241 can abut against the first stepped surface 1411. It should be understood that the connecting block 14 is embedded in the limiting groove 124 through the first protrusion 141 to form a limiting fit with the limiting groove 124; furthermore, the first stepped surface 1411 of the first protrusion 141 forms an abutting fit with the second stepped surface 1241 in the limiting groove 124, so that the connecting block 14 and the pole post 12 form a stable assembly, further ensuring the clamping and fixing effect on the cover plate body 11.

[0057] Please see Figure 8As shown, in some embodiments, the second step surface 1241 has an angle α with the thickness direction X, satisfying 15°≤a≤75°. Specifically, the angle α can be any value among 15°, 25°, 35°, 45°, 55°, 65°, and 75°, or a range between any two adjacent values. It should be understood that the second step surface 1241 is in contact with the first step surface 1411, and the angle setting increases the contact area between the connecting block 14 and the second connecting part 123, increases friction, improves connection stability, and ensures connection strength. On the other hand, the gravity of the connecting block 14 can achieve a self-locking function, preventing the connecting block 14 from accidentally sliding out. The larger the angle α, the more tightly the connecting block 14 can be engaged in the limiting groove 124, saving space.

[0058] Please see Figure 10 As shown, in some embodiments, the connecting block 14 includes a second protrusion 142, which protrudes from the side of the connecting block 14 away from the cover plate body 11. Along the thickness direction X, the second protrusion 142 has a portion that protrudes beyond the first protrusion 141. The cover plate assembly 1 also includes a second welding portion 16, which connects the first step surface 1411 and the second step surface 1241 respectively. By having the portion of the second protrusion 142 protruding beyond the first protrusion 141 along the thickness direction X, the weld formed by the second welding portion 16 is protected, preventing the weld from protruding beyond the connecting block 14. Thus, the weld will not interfere with the interior of the single cell, improving the safety of the single cell and ensuring the welding life and welding strength of the second welding portion 16.

[0059] Please see Figure 5 , Figure 6 , Figure 7 and Figure 11 As shown, in some embodiments, the cover plate assembly 1 further includes a sealing ring 17. The sealing ring 17 includes a first sealing section 171, a second sealing section 172, and a third sealing section 173. The first sealing section 171 is disposed between the main body 121 and the cover plate body 11. The second sealing section 172 is sandwiched between the cover plate body 11 and the connecting block 14. The third sealing section 173 is embedded in the limiting groove 124 and sandwiched between the main body 121 and the connecting block 14. The first sealing section 171 connects the second sealing section 172 and the third sealing section 173. It should be understood that the sealing ring 17 can be inverted T-shaped. The first sealing section 171 achieves isolation between the main body 121 and the cover plate body 11 to achieve insulation. The second sealing section 172 achieves sealing between the cover plate body 11 and the connecting block 14. The third sealing section 173 achieves sealing between the pole post 12 and the connecting block 14.

[0060] Please see Figure 6As shown, in some embodiments, a second recess 111 is provided on the side of the cover plate body 11 facing the connecting block 14. The second recess 111 communicates with the assembly hole 110 and the limiting groove 124. The second recess 111 has a third wall 1110 facing the connecting block 14, and the limiting groove 124 has a fourth wall 1240 facing the connecting block 14. The third wall 1110 and the fourth wall 1240 are on the same plane perpendicular to the thickness direction X. It should be understood that by providing a second recess 111 on the cover plate body 11 to accommodate the second sealing section 172, the space required for sealing assembly is reduced, the height of the cover plate assembly 1 is reduced, and the space utilization rate is improved. By setting the fourth wall 1240 in the limiting groove 124 and the third wall 1110 in the second settling groove 111 to be on the same plane, it is ensured that the compression of the second sealing section 172 and the third sealing section 173 is consistent, thereby improving the assembly efficiency of the cover plate assembly 1 and ensuring the connection stability between the cover plate body 11, the connecting block 14 and the pole post 12. The components are subjected to uniform force, reducing the risk of structural damage caused by excessive local stress.

[0061] This application also discloses a battery pack comprising a single battery cell as described in the above embodiments. Therefore, it can possess all the technical features and effects of the aforementioned single battery cell, which will not be repeated here.

[0062] 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 of other embodiments.

[0063] The present application provides a detailed description of a single battery cell and a battery pack, and uses specific examples to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only for the purpose of helping to understand the technical solutions and core ideas of the present 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. 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 the present application.

Claims

1. A single cell characterized by, The application relates to a cover plate assembly (1) and an electrode assembly (2) arranged on one side of the cover plate assembly (1) in the thickness direction (X). The cover plate assembly (1) comprises: a cover plate body (11) provided with an assembly hole (110) in the thickness direction (X); a pole column (12) penetrating through the assembly hole (110) and provided with a first hole (120) penetrating through the pole column (12) in the thickness direction (X); a sealing plate (13) covering the first hole (120) and connected to the pole column (12). The electrode assembly (2) comprises a tab (21) penetrating into the first hole (120) and connected to the sealing plate (13). The pole column (12) comprises a main body (121) penetrating into the assembly hole (110), a first connecting part (122) arranged on one side of the cover plate body (11) in the thickness direction (X) and surrounding the main body (121), and a second connecting part (123) arranged at one end of the main body (121) away from the first connecting part (122) in the thickness direction (X), wherein the second connecting part (123) is connected to the main body (121) and surrounds a limiting groove (124).

2. The cell according to claim 1, wherein The first hole (120) penetrates through the main body (121) and the second connecting part (123) in the thickness direction (X). The cover plate assembly (1) further comprises a connecting block (14) arranged on the side of the cover plate body (11) away from the first connecting part (122) and partially embedded in the limiting groove (124). The cover plate body (11) is clamped between the first connecting part (122) and the connecting block (14). The pole column (12) comprises a boss (125) connected to the side of the first connecting part (122) away from the cover plate body (11), wherein the boss (125) and the first connecting part (122) surround a first recess (126) in communication with the first hole (120).

3. The cell according to claim 2, wherein The sealing plate (13) penetrates through the first recess (126) and the first hole (120) in the thickness direction (X). The sealing plate (13) has a first wall (131) facing the boss (125), and the boss (125) has a second wall (1251), wherein the first wall (131) and the second wall (1251) are arranged oppositely.

4. The cell according to claim 3, wherein In the thickness direction (X), the sealing plate (13) has a part protruding outside the first recess (126). The cover plate assembly (1) further comprises a first welding part (15) connected to the first wall (131) and the second wall (1251) respectively. ​ 5. The cell according to claim 2, wherein The connecting block (14) comprises a first protrusion (141) protruding from a side of the connecting block (14) facing the second connecting portion (123) and being in abutment with the limiting groove (124), the first protrusion (141) has a first stepped surface (1411) located on a side of the first protrusion (141) away from the cover plate body (11); The limiting groove (124) has a second stepped surface (1241) arranged opposite to the first stepped surface (1411) so that the second stepped surface (1241) is in abutment with the first stepped surface (1411).

6. The cell according to claim 5, wherein The second stepped surface (1241) forms an angle a with the thickness direction (X), and 15°≤a≤75° is satisfied.

7. The cell according to claim 5, wherein The connecting block (14) comprises a second protrusion (142) protruding from a side of the connecting block (14) away from the cover plate body (11), and along the thickness direction (X), the second protrusion (142) has a portion protruding outside the first protrusion (141); The cover plate assembly (1) further comprises a second welding portion (16) connecting the first stepped surface (1411) and the second stepped surface (1241) respectively.

8. The cell according to claim 2, wherein The cover plate assembly (1) further comprises a sealing ring (17) comprising a first sealing section (171), a second sealing section (172) and a third sealing section (173), the first sealing section (171) is arranged between the main body portion (121) and the cover plate body (11), the second sealing section (172) is arranged between the cover plate body (11) and the connecting block (14), the third sealing section (173) is arranged in the limiting groove (124) and arranged between the main body portion (121) and the connecting block (14), the first sealing section (171) is connected to the second sealing section (172) and the third sealing section (173) respectively.

9. The single battery of claim 8, wherein A second sink groove (111) is formed in a side of the cover plate body (11) facing the connecting block (14), the second sink groove (111) is in communication with the assembly hole (110) and the limiting groove (124); The second sink groove (111) has a third wall (1110) facing the connecting block (14), the limiting groove (124) has a fourth wall (1240) facing the connecting block (14), and the third wall (1110) and the fourth wall (1240) are in the same plane perpendicular to the thickness direction (X).

10. A battery pack, characterized by, The single battery as claimed in any one of claims 1 to 9.

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