Shell, battery and battery pack

Abstract

The utility model provides a shell, a battery and a battery pack, and relates to the technical field of batteries. According to the shell provided by the invention, the inner side part of the shell is provided with the air guide groove extending along the height direction of the roll core, and the first open area and the second open area, which are opposite to each other, of the air guide groove are used for air guide of the air guide groove. As the first open area and the second open area respectively exceed the two sides of the naked battery cell in the height direction, when the battery is in thermal runaway, the naked battery cell expands and only abuts against the inner side part of the shell, gas generated on the side, without the anti-explosion valve, of the battery can be guided into the side, with the anti-explosion valve, of the battery through the gas guide groove, and the anti-explosion effect of the battery is improved. Therefore, the gas is guided to the anti-explosion valve and then discharged out of the battery, and battery explosion is avoided. Besides, the air guide groove is formed in the inner side part of the side wall, so that the space for accommodating the naked battery cell in the cavity is not additionally occupied, and the normal energy density of the battery can be ensured while smooth air exhaust of the battery is ensured.

Description

Technical Field

[0001] This application relates to the technical field of batteries, and more particularly to a housing, a battery, and a battery pack. Background Art

[0002] The gas generation behavior of lithium batteries is a natural phenomenon during the charging and discharging process of the batteries. Especially when the battery experiences thermal runaway, the internal gas rapidly accumulates. At this time, if the internal gas cannot be discharged in time, phenomena such as battery explosion will occur.

[0003] During the safety test of cylindrical batteries, it is found that an explosion-proof valve is provided on one side of the cylindrical battery. When the battery undergoes thermal runaway, the internal winding core expands and tightly adheres to the housing, blocking the gap between the positive and negative electrodes, resulting in the gas generated on the side without the explosion-proof valve being unable to be discharged, thus leading to battery explosion. Utility Model Content

[0004] In view of this, this application provides a housing, a battery, and a battery pack, aiming to solve the above technical problems to a certain extent.

[0005] In a first aspect, this application provides a housing for accommodating a bare battery cell. The bare battery cell has a height direction. The housing includes:

[0006] A side wall that encloses a cavity along the height direction for accommodating the bare battery cell.

[0007] Wherein, the side wall has a gas guiding groove that concaves inward from the inner side of the side wall. The gas guiding groove has opposite first and second open regions. The first open region extends beyond one side of the bare battery cell in the height direction, and the second open region extends beyond the other side of the bare battery cell in the height direction, so that the gas guiding groove connects the spaces on both sides of the cavity in the height direction that are located on both sides of the bare battery cell.

[0008] Preferably, the number of the gas guiding grooves is multiple and they are arranged at equal intervals along the inner side of the side wall.

[0009] Preferably, the side wall further defines two openings that are opposite to each other in the height direction. The distance between the first open region and the adjacent opening is 1.5 - 2 mm, and / or the distance between the second open region and the adjacent opening is 1.5 - 2 mm.

[0010] Preferably, the depth of the gas guiding groove is less than or equal to 1 / 3 of the thickness of the side wall.

[0011] In a second aspect, this application provides a battery including the housing as described above.

[0012] Preferably, the battery includes a cover plate assembly, the side wall further defines an opening that is open along the height direction, the cover plate assembly covers the opening, and the cover plate assembly includes:

[0013] A cover body having a through hole and an ear accommodating recess provided outside the through hole, the ear accommodating recess being located on the first side of the cover body;

[0014] A solder tab that covers the through hole and shields the outside of the ear accommodating recess, the solder tab includes a solder tab body, and an ear welding recess is provided on one side of the solder tab body away from the first side of the cover body corresponding to the ear accommodating recess;

[0015] Wherein, the ear is accommodated in the ear accommodating recess and is welded between the solder tab body and the first side of the cover body;

[0016] Wherein, the depth of the ear welding recess is 1 / 3 of the thickness of the solder tab body.

[0017] Preferably, the cover plate assembly further includes a sealing ring, a sealing ring groove is provided on the side of the solder tab body facing the cover body, the sealing ring is clamped in the sealing ring groove and is welded between the solder tab body and the cover body;

[0018] Wherein, a sealing welding groove is provided on one side of the solder tab body away from the first side of the cover body, the sealing welding groove is located outside the position corresponding to the sealing ring groove, and the depth of the sealing welding groove is 1 / 3 of the thickness of the solder tab body.

[0019] Preferably, the solder tab further includes a welding boss provided on one side of the solder tab body away from the first side of the cover body, the welding boss is located at the geometric center of the solder tab body, and the height of the welding boss protruding from the solder tab body is 0.2 - 0.5 mm.

[0020] Preferably, the solder tab is further provided with a reinforcing welding step at the outer edge of the solder tab body, and the reinforcing welding step is lower than 1 / 3 of the thickness of the solder tab body;

[0021] The solder tab body is non-circular in shape, a receiving groove is provided on the first side of the cover body for receiving the solder tab body, the inner edge of the receiving groove is defined by a welding step formed on the cover body, and the welding step is flush with the reinforcing welding step;

[0022] The cover plate assembly further includes an insulating member, the insulating member has the same shape as the cover body and is connected to the second side of the cover body opposite to the first side.

[0023] In a third aspect, the present application provides a battery pack, which includes the battery as described above.

[0024] According to the housing provided by the present application, the inner side of the housing has air guide grooves extending along the height direction of the wound core. The first open area and the second open area opposite to each other in the air guide grooves are used for the air guide grooves to conduct air. Since the first open area and the second open area respectively extend beyond both sides of the bare battery cell in the height direction, this makes the first open area and the second open area respectively located in the two side spaces of the cavity separated by the bare battery cell, so that the air guide grooves communicate these two parts of the space.

[0025] In this way, even when the battery undergoes thermal runaway and the bare battery cell expands and only abuts against the inner side of the housing, the gas generated on the side of the battery without the explosion-proof valve can also be introduced into the side with the explosion-proof valve through the air guide grooves, so that the gas is guided to the explosion-proof valve and then discharged outside the battery, avoiding battery explosion. In addition, arranging the air guide grooves on the inner side of the side wall does not additionally occupy the space in the cavity originally used to accommodate the bare battery cell. While ensuring smooth exhaust of the battery, it can also ensure the normal energy density of the battery.

[0026] To make the above objects, features, and advantages of the present application more obvious and understandable, the following specifically enumerates preferred embodiments and, in conjunction with the accompanying drawings, the detailed description is as follows. Description of the Drawings

[0027] To more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, so they should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other relevant drawings can also be obtained based on these drawings.

[0028] Figure 1 Schematic diagrams showing a part of the bare battery cell, a part of the housing, and a cover plate assembly in the exploded view of the battery provided by the embodiment of the present application;

[0029] Figure 2 Schematic diagram showing a cross-sectional view of the battery provided by the embodiment of the present application;

[0030] Figure 3 Schematic diagram showing an exploded view of the cover plate assembly of the battery provided by the embodiment of the present application;

[0031] Figure 4 Schematic diagram showing a cross-sectional view of the solder joint of the cover plate assembly of the battery provided by the embodiment of the present application;

[0032] Figure 5Schematic diagram showing a cross-sectional view of a battery housing provided according to an embodiment of the present application;

[0033] Figure 6 Schematic diagram showing a plan view of a battery housing provided according to an embodiment of the present application;

[0034] Figure 7 Shows Figure 6 Schematic diagram of an enlarged view of a local position in

[0035] Reference numerals:

[0036] 1 - Cover assembly; 2 - Housing; 21 - Air guide groove; 3 - Bare battery cell; 31 - Tab;

[0037] 11 - Solder tab; 111 - Welding boss; 112 - Tab welding groove; 113 - Sealing welding groove; 114 - Reinforcing welding step; 115 - Sealing ring clamping groove; 12 - Sealing ring; 13 - Cover body; 131 - Tab receiving groove; 132 - Through hole; 133 - Welding step; 14 - Insulating member. Detailed implementation manners

[0038] The technical solutions of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0039] In the description of the present application, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is 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 thus cannot be construed as a limitation of the present application. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0040] In the description of the present application, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.

[0041] In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0042] According to the housing 2 provided in the first aspect of the embodiments of the present application, the structure and working principle of the housing 2 will be specifically described below in conjunction with Figure 1 、 2 、5, 6 and 7.

[0043] According to the housing 2 provided in the embodiments of the present application, the housing 2 is used to accommodate the bare battery cell 3. The bare battery cell 3 has a height direction, and the housing 2 includes a side wall. In an embodiment, a cavity is formed by enclosing the side wall. The cavity extends along the height direction and is used to accommodate the bare battery cell 3.

[0044] In an embodiment, the side wall has a gas guiding groove 21. The gas guiding groove 21 is recessed from the inner side portion of the side wall into the side wall. The gas guiding groove 21 has opposite first open areas and second open areas. The first open area extends beyond one side of the bare battery cell 3 in the height direction, and the second open area extends beyond the other side of the bare battery cell 3 in the height direction, so that the gas guiding groove 21 communicates with the spaces on both sides of the bare battery cell 3 in the height direction in the cavity.

[0045] Thus, according to the housing 2 provided in the embodiments of the present application, the inner side portion of the housing 2 has a gas guiding groove 21 extending along the height direction of the wound core. The first open area and the second open area opposite to each other in the gas guiding groove 21 are used for the gas guiding groove 21 to conduct gas. Since the first open area and the second open area respectively extend beyond both sides of the bare battery cell 3 in the height direction, the first open area and the second open area are respectively located in the spaces on both sides of the cavity separated by the bare battery cell 3, so that the gas guiding groove 21 communicates with these two parts of the space.

[0046] In this way, even when the battery undergoes thermal runaway and the bare battery cell 3 expands and only abuts against the inner side portion of the housing 2, the gas generated on the side of the battery without the explosion-proof valve can be introduced into the side with the explosion-proof valve through the gas guiding groove 21, so that the gas is guided to the explosion-proof valve and then discharged outside the battery, avoiding battery explosion. In addition, by providing the gas guiding groove 21 on the inner side portion of the side wall, it does not additionally occupy the space in the cavity originally used to accommodate the bare battery cell 3. While ensuring smooth exhaust of the battery, it can also ensure the normal energy density of the battery.

[0047] In an embodiment, by way of example, the housing 2 can be, for example, a cylindrical housing 2, and the side wall is a cylindrical wall. The battery applied to the housing 2 can be, for example, a cylindrical battery, and the material used for the housing 2 can be, for example, aluminum, and the housing 2 is formed into a substantially aluminum shell. The bare electric core 3 can be, for example, a wound core, and the height direction of the bare electric core 3 is also the height direction of the housing 2, that is, the axial direction of the housing 2.

[0048] According to the housing 2 provided by the embodiment of the present application, the number of the air guide grooves 21 is multiple and is arranged at equal intervals along the inner side of the side wall. In this way, the multiple air guide grooves 21 ensure that the gas can be timely led out to the side where the explosion-proof valve is located, increase the volume of air guiding, and reduce the risk of battery explosion. In the embodiment, the multiple air guide grooves 21 can be arranged at equal intervals on the inner side of the housing 2. By way of example, when observed along the axial direction, these air guide grooves 21 can be symmetrically distributed about the axis.

[0049] In the embodiment, the number of the air guide grooves 21 can be, for example, 6. In addition, the number of the air guide grooves 21 is not limited thereto, and can also be 2, 3, 4, 5, 7 or more.

[0050] According to the housing 2 provided by the embodiment of the present application, the side wall can also define two openings (such as circular openings) that are opposite to each other in the height direction, and the distance between the first open area and the adjacent opening (labeled as L in the figure) is 1.5 - 2 mm. In the embodiment, such a distance is beneficial to ensuring that the first open area does not affect the overall sealing performance of the battery, and at the same time can allow a longer bare electric core 3 to be provided to improve the energy density of the battery. By way of example, the distance between the first open area and the adjacent opening can be, for example, 1.6 mm, 1.7 mm, 1.8 mm or 1.9 mm.

[0051] In the embodiment, as an alternative embodiment of the above first open area, or on the basis of the above first open area, the distance between the second open area and the adjacent opening is 1.5 - 2 mm, and its value and beneficial effects are the same as those of the above first open area, and will not be elaborated herein.

[0052] According to the housing 2 provided by the embodiment of the present application, the depth of the air guide groove 21 can be less than or equal to 1 / 3 of the thickness of the side wall (labeled as H in the figure).

[0053] According to the housing 2 provided by the embodiment of the present application, on the one hand, the depth of the above air guide groove 21 is beneficial to ensuring the smooth progress of air guiding, and on the other hand, the depth of the above air guide groove 21 can enable the housing 2 to have sufficient strength as a whole. By way of example, the depth of the air guide groove 21 can be, for example, 1 / 3, 1 / 4 or 1 / 5 of the thickness of the side wall, that is, the thickness of the housing 2.

[0054] According to the second aspect of the embodiment of the present application, a battery is provided, and the battery includes the housing 2 as above.

[0055] According to a second aspect of the embodiments of the present application, a battery is provided. On the basis of having the above-mentioned housing 2, the battery may have the following cover plate assembly 1. Specifically, in combination with Figures 1 to 7 , the battery includes a cover plate assembly 1. The side wall may further define an opening that is open along the height direction (i.e., the above-mentioned circular opening). The cover plate assembly 1 may be disposed to cover the opening. The cover plate assembly 1 may include a cover body 13 and a welding piece 11.

[0056] Specifically, the cover body 13 has a through hole 132 and an ear tab 31 receiving recess disposed outside the through hole 132. The ear tab 31 receiving recess is located on the first side of the cover body 13. Here, the first side of the cover body 13 may be, for example, the upper side of the cover body 13.

[0057] In an embodiment, the welding piece 11 may be disposed to cover the through hole 132 and shield the outside of the ear tab 31 receiving recess. In an embodiment, the welding piece 11 may include a welding piece main body. On the side of the welding piece main body away from the first side of the cover body 13 (i.e., the upper side of the welding piece main body), an ear tab 31 welding recess may be provided corresponding to the ear tab 31 receiving recess.

[0058] In an embodiment, the ear tab 31 of the bare battery cell 3 may be received in the ear tab 31 receiving recess and welded between the welding piece main body (substantially on the lower side of the welding piece main body) and the first side of the cover body 13 (substantially on the upper side of the cover body 13).

[0059] Thus, for the battery provided according to the embodiments of the present application, when the battery is assembled, the ear tab 31 of the bare battery cell 3 passes through the through hole 132 of the cover body 13 and then can be pressed into the ear tab 31 receiving recess on the cover body 13. This structure is equivalent to directly welding the ear tab 31 between the welding piece 11 and the cover body 13 by using the welding piece 11, thereby omitting the top cover current collector plate component in the prior art that needs to be welded to the ear tab 31 and then welded to the electrode structure in the battery. Thus, the assembly difficulty of the battery is reduced, the production efficiency of the battery is improved, and the cost is effectively reduced. Since the current collector plate component is omitted, the internal space of the battery is increased, which is also beneficial to improving the energy density of the battery.

[0060] In an embodiment, the depth of the ear tab 31 welding recess is 1 / 3 of the thickness of the welding piece main body. In an embodiment, the welding process is performed by laser welding. The laser is applied to the ear tab 31 welding recess, and the energy of the laser is transmitted through the material of the welding piece 11 between the ear tab 31 receiving recess and the ear tab 31 welding recess to the ear tab 31 receiving portion and the ear tab 31, thereby realizing the welding of the ear tab 31.

[0061] Therefore, if the depth of the welding recess of the tab 31 is too shallow, it will increase the energy of the laser accumulated in the solder tab 11 material between the tab receiving recess and the welding recess of the tab 31, resulting in an excessively high temperature of the solder tab 11, which may burn out the tab 31 or cause explosion welding. If the depth of the welding recess of the tab 31 is too deep, the solder tab 11 material between the tab receiving recess and the welding recess of the tab 31 will be too thin, and it is easy to penetrate the solder tab 11 during the welding process.

[0062] In the embodiment, as an implementation, the cover body 13 can be, for example, a circular aluminum sheet. The tab welding recess can be the tab welding groove 112, and the tab receiving recess can be the tab receiving groove 131, and both can be annular grooves.

[0063] According to the battery provided by the embodiment of the present application, the cover plate assembly 1 can further include a sealing ring 12. A sealing ring slot 115 can be provided on one side of the solder tab body facing the cover body 13, and the sealing ring 12 can be clamped in the sealing ring slot 115 and welded between the solder tab body and the cover body 13.

[0064] In the embodiment, a sealing welding groove 113 can be provided on one side (i.e., the upper side) of the first side of the solder tab body away from the cover body 13, and the sealing welding groove 113 can be located outside the position corresponding to the sealing ring slot 115.

[0065] In the embodiment, the welding process of the sealing ring 12 is substantially the same as the welding process of the tab 31. Then, the sealing welding groove 113 for applying laser is located outside the position corresponding to the sealing ring slot 115, so as to be relatively far away from the tab 31, thereby avoiding the influence of the accumulation of welding heat on the tab 31. In the embodiment, as an example, both the sealing welding groove 113 and the sealing ring slot 115 can be rectangular shapes with rounded corners at the four corners, and the depth of the sealing welding groove 113 is 1 / 3 of the thickness of the solder tab body ( Figure 4 marked as W), and its purpose and beneficial effects are the same as those of the depth of the tab 31 welding recess, and will not be elaborated here.

[0066] In the embodiment, the sealing ring 12 is placed on the cover body 13, and then the solder tab 11 is placed in the receiving groove at the corresponding position of the cover body 13 for the above welding.

[0067] According to the battery provided by the embodiment of the present application, the solder tab 11 can further include a welding boss 111 provided on one side of the first side of the solder tab body away from the cover body 13. The welding boss 111 can be located at the geometric center of the solder tab body, and the height of the welding boss 111 protruding from the solder tab body is 0.2 - 0.5 mm.

[0068] In an embodiment, the welding boss 111 can serve as an electrical connection structure for performing a bus bar operation between batteries. That is, the welding boss 111 is substantially formed as a structure similar to a "pole column" located on the upper side of the solder tab body. As an example, the welding boss 111 can be, for example, cylindrical.

[0069] In an embodiment, the welding boss 111 has a certain height to ensure the performance of the bus bar operation between batteries, that is, to provide a welding connection position for the bus bar structure. The height of the welding boss 111 is not too high to reduce the space occupied by the battery in the height direction. Specifically, the height of the welding boss 111 can be, for example, 0.2 mm, 0.3 mm, 0.4 mm, or 0.5 mm.

[0070] According to the battery provided by the embodiment of the present application, the solder tab 11 can also be provided with a reinforcing welding step 114 located at the outer edge of the solder tab body. The reinforcing welding step 114 is lower than 1 / 3 of the thickness of the solder tab body to ensure the strength of the outer edge of the solder tab body.

[0071] In an embodiment, the solder tab body is non-circular. A receiving groove is provided on the first side of the cover body 13. The receiving groove is used to receive the solder tab body. The inner edge of the receiving groove is defined by a welding step 133 formed on the cover body 13. The welding step 133 is flush with the reinforcing welding step 114. As an example, the non-circular shape of the welding body can prevent the welding body from rotating relative to the cover body 13 in the receiving groove. For example, the welding body can be formed as a rectangular structure with rounded corners at the four corners. The shape of the receiving groove is the same as that of the welding body, and the size can be slightly larger than the size of the welding body. In an embodiment, the fact that the welding step 133 is flush with the reinforcing welding step 114 is beneficial to connecting the welding body to the cover body 13 in a reinforcing welding manner.

[0072] According to the battery provided by the embodiment of the present application, the cover plate assembly 1 can further include an insulating member 14. The insulating member 14 can have the same shape as the cover body 13 and is connected to the second side (i.e., the lower side of the cover body 13) opposite to the first side of the cover body 13. Here, the insulating member 14 can further insulate the cover body 13 and the bare battery cell 3. The insulating member 14 can also have a hole for the electrode tab 31 to pass through. The hole here can be coaxial with the through hole 132 on the cover body 13. In an embodiment, the insulating member 14 can be formed of, for example, plastic, and substantially forms the "lower plastic" component in the top cover in the prior art.

[0073] According to a third aspect of the embodiments of the present application, a battery pack is provided. The battery pack includes the battery as described above and also has the beneficial effects as described above, which will not be elaborated here. The number of batteries can be multiple, and the multiple batteries can be cylindrical lithium batteries. In the embodiment, the multiple batteries can form a module in the box of the battery pack, and then form a battery pack. In some other examples, the multiple batteries can be directly packed, that is, CTP (Cell to Pack). In the embodiment, the battery pack can provide electrical energy for an electrical device, and the electrical device can be, for example, an electric vehicle, which realizes driving at least through electric energy drive.

[0074] The above are only the preferred embodiments of the present application, and do not limit the protection scope of the present application. Any equivalent structural transformation made by using the content of the specification and drawings of the present application under the innovative concept of the present application, or direct / indirect application in other related technical fields is included in the protection scope of the present application.

Claims

1. A housing, characterized in that, The housing is used to accommodate a bare battery cell, and the bare battery cell has a height direction. The housing includes: A side wall, which encloses a cavity formed by the side wall. The cavity extends along the height direction and is used to accommodate the bare battery cell; Wherein, the side wall has a gas guiding groove, which is recessed from the inner side of the side wall into the side wall. The gas guiding groove has opposite first and second open areas. The first open area extends beyond one side of the bare battery cell in the height direction, and the second open area extends beyond the other side of the bare battery cell in the height direction, so that the gas guiding groove communicates with the spaces on both sides of the cavity in the height direction where the bare battery cell is located.

2. The housing according to claim 1, characterized in that, The number of the gas guiding grooves is multiple and they are arranged at equal intervals along the inner side of the side wall.

3. The housing according to claim 1, characterized in that, The side wall also defines two openings that are opposite to each other in the height direction. The distance between the first open area and the adjacent opening is 1.5 - 2 mm, and / or the distance between the second open area and the adjacent opening is 1.5 - 2 mm.

4. The housing according to claim 1, wherein The depth of the gas guiding groove is less than or equal to 1 / 3 of the thickness of the side wall.

5. A battery, characterized in that, The battery includes the housing as described in any one of claims 1 to 4.

6. The battery according to claim 5, characterized in that, The battery includes a cover assembly. The side wall also defines an opening that is open along the height direction. The cover assembly covers the opening. The cover assembly includes: A cover body, which has a through hole and an ear accommodating recess provided outside the through hole. The ear accommodating recess is located on the first side of the cover body; A welding piece, which covers the through hole and shields the outside of the ear accommodating recess. The welding piece includes a welding piece body. An ear welding recess is provided on one side of the welding piece body away from the first side of the cover body corresponding to the ear accommodating recess; Wherein, the ear is accommodated in the ear accommodating recess and is welded between the welding piece body and the first side of the cover body; Wherein, the depth of the ear welding recess is 1 / 3 of the thickness of the welding piece body.

7. The battery according to claim 6, wherein, The cover assembly further includes a sealing ring. A sealing ring slot is provided on the side of the welding piece body facing the cover body. The sealing ring is clamped in the sealing ring slot and is welded between the welding piece body and the cover body; Wherein, a sealing welding groove is provided on one side of the welding piece body away from the first side of the cover body. The sealing welding groove is located outside the position corresponding to the sealing ring slot. The depth of the sealing welding groove is 1 / 3 of the thickness of the welding piece body.

8. The battery according to claim 6, wherein, The welding piece further includes a welding boss provided on one side of the welding piece body away from the first side of the cover body. The welding boss is located at the geometric center of the welding piece body. The height of the welding boss protruding from the welding piece body is 0.2 - 0.5 mm.

9. The battery according to claim 6, characterized in that, The welding piece is also provided with a reinforcing welding step located at the outer edge of the welding piece body. The reinforcing welding step is lower than 1 / 3 of the thickness of the welding piece body; The solder tab body is non-circular in shape, and a receiving groove is provided on a first side of the cover body, the receiving groove being configured to receive the solder tab body, an inner edge of the receiving groove being defined by a welding step formed in the cover body, the welding step being flush with the reinforcement welding step; The cover plate assembly further includes an insulating member, the insulating member having the same shape as the cover body and being connected to a second side of the cover body opposite to the first side.

10. A battery pack, characterized in that, The battery pack includes the battery according to any one of claims 5 to 9.

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