Cover plate assembly and battery

Abstract

A cover plate assembly and a battery (100). The cover plate assembly comprises a cover plate (1), electrode posts (2), and connecting pieces (3). The electrode posts (2) are installed on the cover plate (1); each connecting piece (3) comprises an electrode post connecting portion (31) and an electrode tab connecting portion (32); the electrode post connecting portions (31) are connected to the electrode posts (2), first insulating members (4) are provided between the electrode post connecting portions (31) and the cover plate (1), the first insulating members (4) are provided with hook portions (41), the electrode post connecting portions (31) are engaged to the hook portions (41), and crack prevention notches (33) are provided at positions of the electrode post connecting portions (31) adjacent to the electrode tab connecting portion (32).

Description

Cover assembly and battery

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on March 7, 2024, with application number 202420447242.4. The entire contents of the above application are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of batteries, for example, to a cover assembly and a battery. Background Art

[0003] In the related art, a battery primarily comprises an outer shell and a battery cell disposed within the outer shell. The outer shell comprises a housing with an opening and a cover plate covering the opening. The cover plate is provided with a terminal, and the tabs of the battery cell are electrically connected to the terminal via an L-shaped connecting piece. The connecting piece is generally a bent plate-like structure that is relatively thin and has poor strength. However, batteries are susceptible to deformation and fracture due to mechanical vibration and impact during use. For example, when the battery is used in a car, the vibration and impact of the car during driving can easily cause the connecting piece to deform, or even fracture at stress concentration points on the pins (such as the bend in the connecting piece), rendering the battery inoperable. Summary of the Invention

[0004] The present application provides a cover plate assembly that can improve the vibration and impact resistance of the connecting piece and reduce the risk of deformation and breakage of the connecting piece.

[0005] The present application provides a battery, the connecting piece of which is not easy to break, has good performance and long service life.

[0006] In the first aspect, an embodiment of the present application provides a cover plate assembly, comprising a cover plate, a pole and a connecting plate, wherein the pole is mounted on the cover plate, and the connecting plate comprises a pole connecting portion and a pole lug connecting portion connected at an angle, the pole connecting portion being connected to the pole, a first insulating member being arranged between the pole connecting portion and the cover plate, the first insulating member being provided with a hook portion, the pole connecting portion being clamped with the hook portion, and an anti-crack notch being provided on the pole connecting portion adjacent to the pole lug connecting portion.

[0007] In one embodiment, the first insulating member is provided with a limiting portion that matches the outer contour of the anti-crack notch, and the limiting portion is inserted into the anti-crack notch.

[0008] In one embodiment, a transition portion is provided between the tab connection portion and the pole connection portion, and a length of the tab connection portion along the first direction is greater than a length of the transition portion along the first direction.

[0009] In one embodiment, the pole connecting portion is provided with a pole hole connected to the pole, and the tab connecting portion is provided with an extension portion protruding along the first direction and away from the side of the pole hole.

[0010] In one embodiment, the width of the transition portion gradually increases from an end close to the pole connection portion toward an end close to the tab connection portion.

[0011] In one embodiment, a thinning portion is provided at a position of the tab connection portion adjacent to the pole connection portion, and a cross-sectional dimension of the thinning portion along the second direction is smaller than a cross-sectional dimension of a portion of the tab connection portion excluding the thinning portion along the second direction.

[0012] In one embodiment, a limiting groove is provided in a recessed side of the first insulating member facing away from the cover plate, the groove wall of the limiting groove is provided with the hook portion adjacent to the groove opening, the pole connecting portion is provided in the limiting groove and is engaged with the hook portion; and / or, the groove wall of the limiting groove is provided with the limiting portion adjacent to the groove opening, and the limiting portion is inserted into the anti-crack notch.

[0013] In one embodiment, one of the first insulating member and the pole connecting portion is provided with a positioning hole, and the other of the first insulating member and the pole connecting portion is provided with a positioning post, and the positioning post is inserted into the positioning hole.

[0014] In one embodiment, the distance between the abutting surface of the hook portion and the pole connecting portion and the surface where the limiting groove of the first insulating member is located is L, the thickness of the pole connecting portion is H, LH>0.1mm; and / or, the side wall in the anti-crack notch is spaced apart from the limiting portion, and the gap between the limiting portion and the side wall of the anti-crack notch is greater than 0.1mm.

[0015] In one embodiment, the tab connection portion includes a first side surface and a second side surface opposite to each other along a first direction, and the tab connection portion is provided with a slot, which passes through the first side surface and the second side surface, and the slot is configured to be plugged into and matched with the tab of the battery cell.

[0016] In a second aspect, an embodiment of the present application provides a battery, comprising a shell provided with an opening, a battery cell installed in the shell, and the cover assembly described above, wherein the cover assembly covers the opening, and the cover assembly is connected to the tab of the battery cell through the tab connecting portion of the connecting sheet.

[0017] The beneficial effects of this application are:

[0018] Before the pole and the connecting piece are connected, the pole connecting part can be pre-fixed by being clamped to the edge of the first insulating member by the hook part, so as to reduce the difficulty of welding the pole and the pole connecting part. After the connection, the hook part can also play the role of limiting and supporting the connecting piece to prevent the connecting piece from moving in the vertical direction under the action of external force, thereby improving the vibration resistance and impact resistance of the connecting piece and making the connecting piece less likely to deform. By providing an anti-crack notch at the connection between the pole connecting part and the pole lug connecting part, it is beneficial to release the stress at the connection between the pole connecting part and the pole lug connecting part, avoid stress concentration at the connection, thereby improving the tear resistance of the connection and reducing the risk of breakage at the connection due to external force. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG1 is an exploded view of the cover assembly according to an embodiment of the present application.

[0020] FIG2 is a schematic structural diagram of the cover plate assembly according to an embodiment of the present application.

[0021] FIG3 is a cross-sectional view of the cover plate assembly according to an embodiment of the present application.

[0022] FIG4 is an enlarged view of point A in FIG3 .

[0023] FIG5 is an exploded view of the assembly of the connecting piece and the first insulating member according to an embodiment of the present application.

[0024] FIG6 is a second side view of the first insulating member according to the embodiment of the present application.

[0025] FIG7 is a first side view of the first insulating member according to an embodiment of the present application.

[0026] FIG8 is a schematic diagram of the structure of the battery according to an embodiment of the present application. In the figure:

[0027] 1. Cover plate; 11. Third protrusion; 2. Pole; 3. Connecting piece; 31. Pole connecting portion; 32. Tab connecting portion; 321. Thinning portion; 322. Extension portion; 323. First side surface; 324. Second side surface; 325. Slot; 33. Anti-crack notch; 34. Transition portion; 4. First insulating member; 41. Hook portion; 42. Limiting portion; 43. Limiting groove; 44. Demolding hole; 45. First protrusion; 5. Positioning hole; 6. Positioning column; 7. Second insulating member; 71. Second protrusion; 8. Fixing block; 9. Sealing ring; 100. Battery; 10. Housing; 12. Battery cell; 13. Cover plate assembly. DETAILED DESCRIPTION

[0028] In the description of this application, unless otherwise specified or limited, the terms "connected," "connect," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and can refer to internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0029] As shown in Figures 1 to 5, a cover plate assembly provided in the present application includes a cover plate 1, a pole 2 and a connecting plate 3. The pole 2 is installed on the cover plate 1. The connecting plate 3 includes a pole connecting portion 31 and a pole ear connecting portion 32 connected at an angle. The pole connecting portion 31 is connected to the pole 2. A first insulating member 4 is arranged between the pole connecting portion 31 and the cover plate 1. The first insulating member 4 is provided with a hook portion 41. The pole connecting portion 31 is clamped with the hook portion 41. The pole connecting portion 31 is provided with an anti-crack notch 33 at a position adjacent to the pole ear connecting portion 32.

[0030] It can be understood that the cover plate 1, the first insulating member 4 and the connecting piece 3 are arranged from top to bottom, the pole 2 is passed through the cover plate 1 and the first insulating member 4 and welded to the pole connecting portion 31 of the connecting piece 3. Before welding, the pole connecting portion 31 can be pre-fixed by being clamped to the edge of the first insulating member 4 by the hook portion 41 to reduce the difficulty of welding the pole 2 and the pole connecting portion 31. Moreover, after welding, the hook portion 41 can also play the role of limiting and supporting the connecting piece 3 to prevent the connecting piece 3 from moving in the vertical direction under the action of external force, thereby improving the impact and vibration resistance of the connecting piece 3 and making the connecting piece 3 less likely to deform; and by providing an anti-crack notch 33 at the connection between the pole connecting portion 31 and the pole lug connecting portion 32, it is beneficial to release the stress at the connection between the pole connecting portion 31 and the pole lug connecting portion 32, avoiding stress concentration at the connection, thereby improving the tear resistance of the connection and reducing the risk of breakage at the connection due to external force.

[0031] The number of the hook portions 41 may be one or more, and the number of the hook portions 41 is not specifically limited herein.

[0032] Since the anti-crack notch 33 is provided, it provides space for the tab connection portion 32 to deform or shake, making it easy for the tab connection portion 32 to deform or shake significantly toward the anti-crack notch 33 under the action of external force, causing the tab connection portion 32 to break. Based on this, the first insulating member 4 is provided with a limiting portion 42 that matches the outer contour of the anti-crack notch 33, and the limiting portion 42 is inserted into the anti-crack notch 33. When the pole connection portion 31 is installed on the first insulating member 4, the limiting portion 42 can be inserted into the anti-crack notch 33 to block and limit the tab connection portion 32, reduce the deformation of the tab connection portion 32, and make the tab connection portion 32 less likely to deform, which can further reduce the risk of deformation and fracture of the connecting piece 3.

[0033] The crack prevention notch 33 may be a V-shaped notch, a U-shaped notch, a rectangular notch, an arc-shaped notch, or any other irregularly shaped notch. In this embodiment, the crack prevention notch 33 is a V-shaped notch. The V-shaped notch can increase the curvature radius of the connection between the tab connection portion 32 and the pole connection portion 31, thereby effectively releasing stress accumulation during impact vibration.

[0034] The gap between the limiting portion 42 and the anti-crack notch 33 allows the tab connection portion 32 to have a certain amount of deformation space. It is understandable that if the tab connection portion 32 deforms significantly, it will easily break. If the movement of the tab connection portion 32 is completely restricted, stress concentration will occur at the connection between the pole connection portion 31 and the tab connection portion 32, causing the connecting piece 3 to become too rigid, which may also cause the connecting piece 3 to break. By setting the gap between the limiting portion 42 and the anti-crack notch 33, space can be reserved for the tab connection portion 32 to provide elastic deformation to release stress, and the limiting portion 42 can block and limit the tab connection portion 32 to prevent the tab connection portion 32 from deforming too much and breaking.

[0035] If the gap between the limiting portion 42 and the anti-crack notch 33 is too small, the tab connection portion 32 may have insufficient deformation space, resulting in excessive rigidity of the connecting piece 3. If the gap between the limiting portion 42 and the anti-crack notch 33 is too large, the tab connection portion 32 may be excessively deformed and break. Optionally, the gap between the limiting portion 42 and the sidewall of the anti-crack notch 33 is greater than 0.1 mm. Optionally, the gap between the limiting portion 42 and the sidewall of the anti-crack notch 33 is 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, etc.

[0036] Optionally, an elastic gasket (not shown in the figure) is provided in the gap between the limiting portion 42 and the anti-crack notch 33 to enable the tab connection portion 32 to elastically abut against the limiting portion 42, thereby buffering the bursting of the tab connection portion 32 and making the connecting piece 3 less likely to break.

[0037] A limiting groove 43 is recessed on the side of the first insulating member 4 facing away from the cover plate 1. A hook portion 41 is provided on the wall of the limiting groove 43, adjacent to the notch. The pole connecting portion 31 is disposed within the limiting groove 43 and engages with the hook portion 41 to prevent the pole connecting portion 31 from falling out. This design accommodates the pole connecting portion 31 by accommodating the limiting groove 43 to restrict circumferential rotation of the pole connecting portion 31 along the pole 2. Simultaneously, the hook portion 41 limits vertical movement of the pole connecting portion 31, thereby jointly limiting the connecting piece 3 and making the connecting piece 3 more stable and reliable.

[0038] In order to facilitate the installation of the pole connecting portion 31 in the limiting groove 43 and the clamping connection with the hook portion 41, the distance between the abutting surface of the hook portion 41 and the pole connecting portion 31 and the surface where the notch of the limiting groove 43 of the first insulating member 4 is located is L, and the thickness of the pole connecting portion 31 is H, where L is greater than H.

[0039] When LH is too large, the volume of the first insulating member 4 will increase, thereby increasing the space occupied by the battery housing. When LH is too small, the difficulty of installing the connecting piece 3 and the first insulating member 4 will increase. Optionally, LH>0.1mm, and LH can be selected to be 0.1mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm, etc.

[0040] A limiting portion 42 is provided on the wall of the limiting groove 43 adjacent to the groove opening. The limiting portion 42 is located on the first insulating member 4 at a position corresponding to the anti-crack notch 33 and is inserted into the anti-crack notch 33. The limiting portion 42 cooperates with the anti-crack notch 33 to not only prevent the connecting piece 3 from deformation and fracture, but also to provide a positioning function, thereby positioning the connecting piece 3 and the first insulating member 4 for installation.

[0041] Optionally, the cross-sectional dimension of the limiting groove 43 is larger than the cross-sectional dimension of the pole connecting portion 31 , so that the pole connecting portion 31 is loosely fitted with the limiting groove 43 , facilitating installation of the pole connecting portion 31 in the limiting groove 43 .

[0042] The pole connecting portion 31 is provided with a pole hole, the first insulating member 4 is provided with a first opening, and the cover plate 1 is provided with a second opening. One end of the pole 2 passes through the first opening and the second opening and is inserted into the pole hole and welded to the pole hole. The pole tab connecting portion 32 is connected to the edge area of ​​the pole tab connecting portion 32 on the side away from the pole hole to increase the distance between the pole tab connecting portion 32 and the pole hole, so as to reduce the impact torque borne by the connection between the pole connecting portion 31 and the pole tab connecting portion 32, and further improve the impact resistance and vibration resistance of the connection.

[0043] Optionally, one of the first insulating member 4 and the pole connecting portion 31 is provided with a positioning hole 5, and the other of the first insulating member 4 and the pole connecting portion 31 is provided with a positioning column 6, which is inserted into the positioning hole 5. For example, in conjunction with Figures 1, 2 and 5, a positioning column 6 is protruding from the bottom of the limiting groove 43, and a positioning hole 5 is provided on the pole connecting portion 31. The positioning column 6 is plugged into the positioning hole 5 to position and install the pole connecting portion 31, ensuring that the pole hole on the pole connecting portion 31 is aligned with the first opening and the second opening. In addition, the plugging and matching of the positioning column 6 and the positioning hole 5 can also limit the movement of the connecting piece 3 in the horizontal direction, which is beneficial to improving the impact and vibration resistance of the connecting piece 3.

[0044] Optionally, the cover plate 1 is provided with a first groove, and the first insulating member 4 is provided with a first protrusion 45, and the first groove and the first protrusion 45 are plugged together to limit relative twisting of the first insulating member 4 and the cover plate 1. In other embodiments, the cover plate 1 may also be provided with a protrusion, and the first insulating member 4 may be provided with a groove, so that the protrusion and the groove are plugged together.

[0045] Optionally, the connecting piece 3 can be integrally bent from a plate to form the pole connecting portion 31 and the tab connecting portion 32 , so as to improve the overall strength of the connecting piece 3 .

[0046] Optionally, a transition portion 34 is provided between the tab connection portion 32 and the post connection portion 31. The length of the tab connection portion 32 along the first direction (the x-direction in the figure) is greater than the length of the transition portion 34 along the first direction. This design increases the area of ​​the tab connection portion 32, thereby increasing the welding area between the tab connection portion 32 and the tab. This improves the welding effect and the stability of the connection between the tab connection portion 32 and the tab. Furthermore, the shorter length of the transition portion 34 along the first direction, i.e., the smaller connection area between the transition portion 34 and the post connection portion 31, makes it easier for the transition portion 34 to elastically deform under external forces to relieve stress, thus avoiding stress concentration at the bend of the connecting piece 3.

[0047] Exemplarily, the tab connection portion 32 is provided with an extension portion 322 protruding along the first direction and away from the side of the terminal hole, wherein the first direction is the same as the direction in which the tab extends out of the battery cell. It is understandable that since the terminal connection portion 31 is installed in the limiting groove 43 of the first insulating member 4, if the tab connection portion 32 protrudes from the limiting groove 43 away from the slot wall of the terminal hole, it will cause the tab connection portion 32 to interfere with the slot wall of the limiting groove 43. However, by providing the extension portion 322, the tab connection portion 32 can be widened in the direction of the tab extension, so that the length of the tab connection portion 32 in the first direction is greater than the length of the transition portion 34 in the first direction, thereby increasing the welding area of ​​the tab connection portion 32. At the same time, a notch can be formed in the transition portion 34 of the connecting piece 3, through which the first insulating member 4 can be avoided, thereby spacing the tab connection portion 32 below the limiting groove 43, so that the widened tab connection portion 32 can be smoothly connected to the tab.

[0048] Optionally, the limiting groove 43 has an outer groove wall along the first direction and relatively far away from the pole hole, and the side of the extension 322 along the first direction and away from the pole hole is flush with the outer groove wall. If the length of the extension 322 along the first direction is too large, the space occupied by the connecting piece 3 inside the battery shell will be increased, reducing the energy density of the battery. If the length of the extension 322 along the first direction is too small, the welding effect between the tab connection part 32 and the tab will be reduced. This design improves the space utilization inside the battery shell by utilizing the space below the outer groove wall inside the original battery shell to widen the extension 322. There is no need to widen the connecting piece 3 by reducing the size of the battery cell. Therefore, the welding effect between the connecting piece 3 and the tab can be improved without affecting the battery density.

[0049] Optionally, the tab connection portion 32 includes a first side surface 323 and a second side surface 324 that are opposite each other along a first direction. The tab connection portion 32 is provided with a slot 325 that extends through the first side surface 323 and the second side surface 324. The slot 325 is configured to engage with the tab. With this design, the tab can be pre-fixed by inserting it into the slot 325 before being welded. This allows the two side surfaces of the slot 325 along the second direction (the y direction in the figure) to abut and weld against the two side surfaces of the tab along the second direction, thereby further increasing the connection area between the tab connection portion 32 and the tab, improving the welding effect and making the connection more stable.

[0050] Alternatively, referring to Figure 6, the width of the transition portion 34 gradually increases from the end near the pole connection portion 31 toward the end near the tab connection portion 32. This design allows the stress at the bend of the connecting piece 3 to gradually change through the transition portion 34 and be transferred to the tab connection portion 32, thereby avoiding damage caused by sudden stress changes.

[0051] Optionally, referring to FIG7 , a thinned portion 321 is provided on the tab connection portion 32 adjacent to the post connection portion 31. The cross-sectional dimension of the thinned portion 321 along the second direction is smaller than the cross-sectional dimension of the portion of the tab connection portion 32 excluding the thinned portion 321. In this embodiment, the thickness of the thinned portion 321 is smaller than that of the tab connection portion 32. When the connecting piece 3 is subjected to an external force, the thinner thinned portion 321 is more likely to deform flexibly to prevent the connecting piece 3 from breaking due to excessive external force. At the same time, the thinned portion 321 has a higher resistance and can serve as a fuse structure to provide overcurrent protection, preventing thermal runaway of the battery.

[0052] The first insulating member 4 can be a plastic part integrally formed by injection molding. A demoulding hole 44 is provided at the position of the first insulating member 4 corresponding to the hook portion 41. It is understood that inserts are used during injection molding to facilitate molding. Inserts are irregular mold accessories that are embedded in the mold to fill the space between the templates. During injection molding, a demoulding hole 44 is formed so that the insert can be inserted into the demoulding hole 44. That is, the insert portion can fill the interior of the mold to facilitate molding of the hook portion 41, while the insert portion is located outside the mold. After injection molding is completed, the insert can be quickly pulled out of the demoulding hole 44 for easy demoulding.

[0053] The cover plate assembly also includes a second insulating member 7, which is arranged on a side of the cover plate 1 facing away from the first insulating member 4. A fixing block 8 is also provided on the side of the second insulating member 7 facing away from the cover plate 1. The second insulating member 7 is provided with a third opening, and the fixing block 8 is provided with a rivet hole. The end of the pole 2 away from the connecting plate 3 passes through the first opening, the second opening, and the third opening in sequence and is riveted to the rivet hole.

[0054] Optionally, referring to Figures 1, 3 and 4, the second insulating member 7 is provided with a second protrusion 71, and the fixing block 8 is provided with a second groove, which is plugged into and fits with the second protrusion 71 to limit the relative torsion of the second insulating member 7 and the fixing block 8, thereby improving the stability of the pole 2.

[0055] The cover plate 1 is provided with a third protrusion 11 , and the second insulating member 7 is provided with a third groove. The third groove is plugged into and fits with the third protrusion 11 to limit relative torsion between the second insulating member 7 and the cover plate 1 , thereby further improving the stability of the pole 2 .

[0056] 1 and 4 , the cover assembly further includes a sealing ring 9, which is sleeved on the outer periphery of the pole 2 and fills the gap between the third opening and the pole 2 and between the bottom surface of the cover 1 and the boss on the outer periphery of the pole 2 to ensure the sealing performance of the cover assembly.

[0057] 8 , the present application further provides a battery 100, comprising a housing 10 having an opening, a battery cell 12 mounted within the housing, and a cover assembly 13 as described in any of the above embodiments. The cover assembly covers the opening, and the cover assembly is connected to the tabs of the battery cell via the tab connection portion 32 of the connecting piece 3. By using the cover assembly as described in any of the above embodiments, the battery of the present application is less likely to fail due to deformation or fracture of the connecting piece 3, resulting in better battery performance and a longer service life.

[0058] In the description herein, terms such as "upper," "lower," "left," and "right" are used for ease of description and simplified operation based on the orientations or positions shown in the accompanying drawings. They are not intended to indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific manner. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first" and "second" are used solely for descriptive purposes and have no special meaning.

[0059] Throughout this specification, references to terms such as "an embodiment" or "example" indicate that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example.

[0060] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A cover plate assembly, comprising a cover plate, a pole and a connecting piece, wherein the pole is mounted on the cover plate, the connecting piece comprises a pole connecting portion and a pole lug connecting portion connected at an angle, the pole connecting portion is connected to the pole, a first insulating member is provided between the pole connecting portion and the cover plate, the first insulating member is provided with a hook portion, the pole connecting portion is engaged with the hook portion, and an anti-crack notch is provided on the pole connecting portion adjacent to the pole lug connecting portion.

2. The cover plate assembly according to claim 1, wherein: The first insulating member is provided with a limiting portion that matches the outer contour of the anti-crack notch, and the limiting portion is inserted into the anti-crack notch.

3. The cover plate assembly according to claim 1, wherein: A transition portion is provided between the tab connection portion and the pole connection portion, and a length of the tab connection portion along a first direction is greater than a length of the transition portion along the first direction.

4. The cover plate assembly according to claim 3, wherein: The pole connecting portion is provided with a pole hole connected to the pole, and the tab connecting portion is provided with an extension portion protruding along the first direction and away from the side of the pole hole.

5. The cover plate assembly according to claim 3, wherein: The width of the transition portion gradually increases from an end close to the pole connection portion toward an end close to the tab connection portion. The cover plate assembly according to claim 1 , wherein: A thinning portion is provided on the tab connection portion adjacent to the pole connection portion, and a cross-sectional dimension of the thinning portion along the second direction is smaller than a cross-sectional dimension of a portion of the tab connection portion excluding the thinning portion along the second direction.

7. The cover plate assembly according to claim 2, wherein: A limiting groove is provided on the side recess of the first insulating member facing away from the cover plate, the groove wall of the limiting groove is provided with the hook portion adjacent to the groove opening, the pole connecting portion is provided in the limiting groove and is engaged with the hook portion; and / or the groove wall of the limiting groove is provided with the limiting portion adjacent to the groove opening, and the limiting portion is inserted into the anti-crack notch.

8. The cover plate assembly according to any one of claims 1 to 7, wherein: One of the first insulating member and the pole connecting portion is provided with a positioning hole, and the other of the first insulating member and the pole connecting portion is provided with a positioning post, and the positioning post is inserted into the positioning hole.

9. The cover plate assembly according to any one of claims 2, wherein: The distance between the abutting surface of the hook portion and the pole connecting portion and the surface where the limiting groove of the first insulating member is located is L, the thickness of the pole connecting portion is H, LH>0.1mm; and / or, the side wall in the anti-crack notch is spaced apart from the limiting portion, and the gap between the limiting portion and the side wall in the anti-crack notch is greater than 0.1mm.

10. The cover plate assembly according to any one of claims 1 to 7, wherein: The tab connection portion includes a first side surface and a second side surface that are opposite to each other along a first direction. The tab connection portion is provided with a slot that passes through the first side surface and the second side surface. The slot is configured to be plugged into and matched with the tab of the battery cell.

11. A battery comprising a shell with an opening, a battery cell installed in the shell, and the cover assembly according to any one of claims 1 to 10, wherein the cover assembly covers the opening and is connected to the tab of the battery cell through the tab connecting portion of a connecting piece.

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