Battery connecting piece and battery
By designing the elastic heat dissipation part on the lithium-ion battery connection sheet to contact the metal cover plate, the problem of insufficient thermal conductivity is solved, the thermal conduction rate and safety performance of the battery are improved, thermal runaway is avoided, and the battery weight and cost are not increased.
Patent Information
- Application Number
- CN202510491446.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-18
- Publication Date
- 2025-07-08
AI Technical Summary
The thermal conductivity of the existing lithium-ion battery connecting plates is insufficient, resulting in heat accumulation of the battery under high load, affecting safety performance.
A battery connecting piece is designed, including an elastic heat dissipation part, which forms a raised structure to contact the metal cover plate by cutting and bending, which improves the heat conduction rate, and an inclined assembly part is provided on the main body of the connecting piece to facilitate fitting with the inner wall of the shell to avoid insufficient welding.
It improves the thermal conduction rate of the battery, avoids thermal runaway, improves safety performance, and does not increase weight and cost to ensure welding quality.
Smart Images
Figure CN120280663A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of batteries, and particularly to a battery connecting piece and a battery. Background Art
[0002] At present, with the increasing maturity of lithium-ion battery technology, lithium-ion batteries are widely used as power batteries in the field of electric vehicles. The structural parts of lithium-ion batteries are also important components of lithium-ion power batteries. They not only provide guarantee for the safety and reliability of lithium-ion batteries, but also take into account the connection between the internal chemical system of lithium-ion batteries and external modules and even Packs. Due to various connection relationships existing inside the structural parts and the requirements of sealing performance and over-current heat conduction performance need to be taken into account at the same time, the design scheme of the structural parts is particularly important. With the development of the industry, the requirements for the fast charging performance of batteries are getting higher and higher, and the requirements for the heat dissipation ability and safety ability of lithium batteries are also getting higher and higher. As is well known, the heat dissipation of cylindrical pole groups is mainly through axial conduction. As a structure connecting the upper and lower parts inside the battery cell, the connecting piece is an important heat conduction carrier of the battery and plays a crucial role in the performance of the battery. Therefore, it is currently necessary to develop a connecting piece with better heat conduction ability. Summary of the Invention
[0003] The purpose of the present application is to provide a battery connecting piece and a battery, which to a certain extent solve the technical problem that there is a need to develop a connecting piece with better heat conduction ability in the prior art.
[0004] The present application provides a battery connecting piece, which is applied to a battery. The battery includes a housing, a pole group and a metal cover plate. The metal cover plate seals the pole group in the housing. The battery connecting piece includes a connecting piece main body, which is used to be installed at one end of the pole group and is connected to the pole ear of the pole group. The connecting piece main body is formed with an elastic heat dissipation part, and the elastic heat dissipation part is used to extend to the metal cover plate and contact the metal cover plate for conducting heat.
[0005] In the above technical solution, further, the elastic heat dissipation part is a structure formed by cutting and lifting the corresponding position of the connecting piece main body and protruding from the connecting piece main body; or The elastic heat dissipation part and the connecting piece main body are of a split structure and are assembled and connected together.
[0006] In any of the above technical solutions, further, the number of the elastic heat dissipation parts is multiple, and they are sequentially and spaced apart along the circumferential direction of the connecting piece main body.
[0007] In any of the above technical solutions, further, a plurality of connection areas are formed on the connection piece body, and any one of the connection areas is connected to the tab of the electrode group, and the plurality of connection areas are sequentially arranged at intervals along the circumferential direction of the connection piece body.
[0008] In any of the above technical solutions, further, the elastic heat dissipation part is arranged inside the inner ring of the annular structure surrounded by the plurality of connection areas; or The elastic heat dissipation part is arranged between at least one group of adjacent two connection areas.
[0009] In any of the above technical solutions, further, the connection area is fan-shaped.
[0010] In any of the above technical solutions, further, an inclined assembly part is formed on the outer edge of the connection piece body and is inclined with respect to the thickness direction of the connection piece body, and the inclined assembly part is used for abutting against the inner part of the housing.
[0011] In any of the above technical solutions, further, the inclination angle of the inclined assembly part with respect to the thickness direction of the connection piece body is ɑ, and 0° < ɑ ≤ 45°.
[0012] In any of the above technical solutions, further, along the direction from the center of the connection piece body towards the outside, the length of the inclined assembly part is b, and 0 < b ≤ 5 mm.
[0013] In any of the above technical solutions, further, the inclined assembly part is an annular structure.
[0014] In any of the above technical solutions, further, a liquid injection through hole is formed in the connection piece body.
[0015] The present application also provides a battery, including the battery connection piece according to any of the above technical solutions. Therefore, it has all the beneficial technical effects of the battery connection piece, and will not be elaborated here.
[0016] In the above technical solution, further, the battery further includes a housing, an electrode group, and a metal cover plate; wherein, the metal cover plate seals the electrode group in the housing; the connection piece body is arranged at one end of the electrode group and is connected to the tab of the electrode group; the connection piece body is formed with an elastic heat dissipation part, and the elastic heat dissipation part extends to the metal cover plate and is in contact with the metal cover plate for conducting heat.
[0017] Compared with the prior art, the beneficial effects of the present application are: The core design of the battery connection piece provided in this application lies in setting a raised elastic heat dissipation part, enabling it to directly contact the metal cover plate, enhancing the heat conduction effect, further improving the heat conduction rate of the electrode group, avoiding the thermal runaway situation caused by heat accumulation in the battery under the conditions of hot box, thermal propagation, and short circuit, improving the safety performance of the battery. Moreover, preferably, this structure is achieved by cutting, bending, and lifting the corresponding positions on the connection piece body, enabling it to directly contact the metal cover plate, and it can be integrally cast by a mold during the actual manufacturing process without increasing the cost. Additionally, a hollow area is formed below the elastic heat dissipation part, which will not cause an additional impact on the weight of the battery. Furthermore, the elastic heat dissipation part and the connection area, such as the welding area, are staggered and will not affect each other, thereby avoiding insufficient overcurrent caused by insufficient welding.
[0018] In addition, an inclined assembly part is provided at the outer edge of the battery connection piece, facilitating its fitting with the inner wall of the housing during welding, avoiding problems such as welding explosion points caused by insufficient fitting, and its inclination angle and length can be selected according to actual needs, being flexible and variable. Brief Description of the Drawings
[0019] In order to more clearly illustrate the specific embodiments of this application or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of this application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.
[0020] Figure 1 It is a schematic structural diagram of the battery connection piece provided by an embodiment of this application; Figure 2 It is another schematic structural diagram of the battery connection piece provided by an embodiment of this application; Figure 3 It is yet another schematic structural diagram of the battery connection piece provided by an embodiment of this application; Figure 4 It is yet another schematic structural diagram of the battery connection piece provided by an embodiment of this application.
[0021] Reference Signs: 1 - Battery connection piece, 11 - Connection piece body, 12 - Elastic heat dissipation part, 13 - Connection area, 14 - Inclined assembly part, 15 - Liquid injection through hole. Detailed Description of the Embodiments
[0022] The following will clearly and completely describe the technical solutions of this application in conjunction with the drawings. Obviously, the described embodiments are some, but not all, of the embodiments of this application.
[0023] The components of the embodiments of the present application that are usually depicted and shown in the accompanying drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application claimed, but merely represents selected embodiments of the present application.
[0024] Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present application.
[0025] 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 accompanying drawings. It 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 therefore should not 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.
[0026] In the description of the present application, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", "connected to" 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 circumstances.
[0027] Next, refer to Figures 1 to 4 to describe a battery connecting piece and a battery according to some embodiments of the present application.
[0028] Embodiment 1 Refer to Figure 1 and Figure 2 As shown, an embodiment of the present application provides a battery connecting piece 1, which is applied to a battery. The battery includes a housing, a pole group, and a metal cover plate. The metal cover plate seals the pole group in the housing. The battery connecting piece 1 includes a connecting piece main body 11. The connecting piece main body 11 is used to be installed at one end of the pole group and is connected to the pole ear of the pole group; an elastic heat dissipation part 12 is formed on the connecting piece main body 11, and the elastic heat dissipation part 12 is used to extend to the metal cover plate and contact the metal cover plate for conducting heat.
[0029] According to the structure described above, the present application provides a novel battery connecting piece 1. Among them, an elastic heat dissipation part 12 is provided on the connecting piece body, and the elastic heat dissipation part 12 extends to the metal cover plate and contacts the metal cover plate, so as to conduct heat out of the battery interior, improving the battery's performance and safety performance during use. Furthermore, preferably, the entire material of the battery connecting piece 1 is metal, and its contact with the metal cover plate plays a good role in heat conduction.
[0030] In this embodiment, preferably, as Figure 2 shown, the elastic heat dissipation part 12 is a structure formed by cutting and then lifting the corresponding position of the connecting piece body 11, protruding from the connecting piece body 11. At this time, it is ensured that one side of the elastic heat dissipation part 12 is connected to the rest of the connecting piece body 11. Of course, it is not limited to this. According to the structure described above, by cutting and then bending and lifting at the corresponding position on the connecting piece body 11, the protruding elastic heat dissipation part 12 is naturally formed, enabling it to contact the metal cover plate, thereby improving the heat conduction rate of the electrode group and avoiding the occurrence of thermal runaway due to heat accumulation in the battery under the conditions of a hot box, thermal propagation, or short circuit, further improving the battery's safety performance. Moreover, there is no additional structure added, and the battery weight is not increased additionally, which is conducive to lightweight design. And during the actual manufacturing process, it can be integrally cast by a mold without causing an increase in cost.
[0031] Furthermore, preferably, when the elastic heat dissipation part 12 is not lifted, that is, when it is flattened, it has an isosceles trapezoidal structure, ensuring that it has sufficient contact area with the metal cover plate after being lifted, and the connection area between its root and the connecting piece body 11 is large, making the elastic heat dissipation part 12 not easily break, etc. Moreover, the above shape is convenient for processing and manufacturing. Of course, it is not limited to this, and the shape of the elastic heat dissipation part 12 can also be designed according to actual needs.
[0032] It should be noted that: the structure and forming method of the elastic heat dissipation part 12 are not limited to the above, and can also be designed according to actual needs. For example: the elastic heat dissipation part 12 and the connecting piece body 11 are of a split structure and are assembled and connected together, for example, they can be connected by welding or gluing, etc. In this embodiment, preferably, as Figure 1 and Figure 2 shown, the number of the elastic heat dissipation parts 12 is multiple, and they are sequentially arranged at intervals along the circumferential direction of the connecting piece body 11. According to the structure described above, using multiple elastic heat dissipation parts 12 can further improve the heat dissipation effect. Of course, it is not limited to this, and the number of the elastic heat dissipation parts 12 can also be one, which is specifically selected according to actual needs. In this embodiment, preferably, asFigure 1 As shown, the connecting piece body 11 is formed with a plurality of connecting areas 13, and any one of the connecting areas 13 is connected to the tab of the electrode group, and the plurality of connecting areas 13 are arranged at intervals in sequence along the circumferential direction of the connecting piece body 11. According to the structure described above, a plurality of connecting areas 13 are arranged on the connecting piece body 11, thereby improving the stability and firmness of the connection with the tab of the unit.
[0033] Furthermore, preferably, embossing is formed on the connecting area 13, and it can be connected to the tab of the electrode group by welding. Of course, the connection method between the connecting piece body 11 and the tab of the electrode group is not limited to the above, and can also be selected according to actual needs.
[0034] It should be noted that: the number of the connecting areas 13 is not limited to a plurality, and can also be one. This one connecting area 13 can be fan-shaped or annular, etc., and is specifically selected according to actual needs. In this embodiment, preferably, as Figure 1 shown, the elastic heat dissipation part 12 is arranged inside the inner ring of the annular structure surrounded by the plurality of connecting areas 13. According to the structure described above, all the elastic heat dissipation parts 12 are arranged inside the inner ring of the annular structure surrounded by the plurality of connecting areas 13, so that the elastic heat dissipation part 12 can effectively avoid the connecting area 13, and thus will not affect the connection operation between the connecting area 13 and the tab of the electrode group, such as welding operation.
[0035] It should be noted that: the positional relationship between the elastic heat dissipation part 12 and the connecting area 13 is not limited to the above. For example, as Figure 3 and Figure 4 shown, at least one elastic heat dissipation part 12 can also be arranged between at least one group of adjacent two connecting areas 13, that is to say, an elastic heat dissipation part 12 is arranged in the area between two adjacent connecting areas 13, which can also make the elastic heat dissipation part 12 and the connecting area 13 avoid each other and do not interfere with each other. In this embodiment, preferably, as Figure 1 shown, the connecting area 13 is fan-shaped, with a large covering area and a regular shape of the area, which is convenient for operations such as welding. Of course, the shape of the connecting area 13 is not limited to this, and can also be square or circular, etc., and is specifically selected according to actual needs.
[0036] In this embodiment, preferably, as Figure 1 and Figure 2 shown, the outer edge of the connecting piece body 11 is formed with an inclined assembly part 14 that is inclined with respect to the thickness direction of the connecting piece body 11, and the inclined assembly part 14 is used for abutting against the inside of the housing. According to the structure described above, the inclined assembly portion 14 presents a certain angle with the connecting piece body 11, which is convenient for it to fit against the inner wall of the housing during welding, avoiding problems such as welding explosion points due to insufficient fitting.
[0037] Furthermore, preferably, the inclined assembly portion 14 and the connecting piece body 11 can be an integral structure or a split structure, and can be connected by welding or other means, and are specifically selected according to actual needs.
[0038] It should be noted that: it is not limited to setting the inclined assembly portion 14 on the outer edge of the battery connecting piece 1 as described above, and it abuts against the inside of the battery housing. It is also possible not to provide this inclined assembly portion 14, and the outer edge of the connecting piece body 11 can directly abut against the inside of the housing. In this case, the housing and the battery connecting piece 1 are electrified with the same polarity. It is also possible to keep a certain gap between the outer edge of the connecting piece body 11, that is, the two do not contact. In this case, the electrified situation between the battery connecting piece 1 and the housing can be designed according to actual needs. When the battery connecting piece 1 is in contact with the battery housing, it should also be noted that: the aforementioned housing can only be electrified with one polarity, so it can only contact a metal cover plate of one polarity, such as a negative metal cover plate, and cannot contact the negative metal cover plate and the positive metal cover plate at the same time. In this case, it is necessary to ensure that the battery connecting piece 1 is provided only on the metal cover plate at one open end of the housing; when the battery connecting piece 1 is not in contact with the housing, both the negative metal cover plate and the positive metal cover plate of the battery can be provided with the battery connecting piece 1 provided in this application.
[0039] In this embodiment, preferably, as Figure 2 shown, the inclination angle of the inclined assembly portion 14 with respect to the thickness direction of the connecting piece body is α, and 0° < α ≤ 45°.
[0040] According to the structure described above, if the inclination angle of the inclined assembly portion 14 with respect to the thickness direction of the connecting piece body is too large, it is not easy to enter the housing. If the inclination angle of the inclined assembly portion 14 with respect to the thickness direction of the connecting piece body is too small, after this connecting piece is assembled with the housing, it cannot be ensured that it fits tightly against the housing.
[0041] In this embodiment, preferably, as Figure 1 shown, along the direction from the center of the connecting piece body 11 towards the outside, the length of the inclined assembly portion 14 is b, and 0 < b ≤ 5 mm.
[0042] According to the structure described above, if the connecting piece body 11 is too long, it is not easy to enter the housing. If the connecting piece body 11 is too short, after this connecting piece is assembled with the housing, it cannot be ensured that it fits tightly against the housing.
[0043] In this embodiment, preferably, asFigure 1 and Figure 2 As shown in Figure 2 , the inclined assembly part 14 is of an annular structure. According to the structure described above, since the entire circumferential edge of the connecting piece needs to cooperate with the interior of the housing, the inclined assembly part 14 is designed as an annular structure, which improves the stability and firmness after the connection between the connecting piece and the housing. It should be noted that: the structure of the inclined assembly part 14 is not limited to the above. It is also in a sector-annular shape, and its number is multiple, and they are sequentially arranged at intervals along the entire circumference of the connecting piece body 11.
[0044] In this embodiment, preferably, as Figure 1 and Figure 2 shown, the connecting piece body 11 is formed with a liquid injection through hole 15, which is convenient for liquid injection. In summary, the core design of the battery connecting piece 1 provided in this application lies in the provision of the raised elastic heat dissipation part 12. Preferably, this structure is achieved by cutting, bending and lifting the corresponding position on the connecting piece body 11, so that it can be in direct contact with the metal cover plate. And in the actual manufacturing process, it can be integrally cast by a mold, which will not cause an increase in cost. Moreover, a hollow area is formed below the elastic heat dissipation part 12, which will not cause an additional impact on the weight of the battery. And the elastic heat dissipation part 12 is staggered from the connection area 13, such as the welding area, and will not affect each other. Thus, the overcurrent deficiency caused by insufficient welding is avoided. At the same time, the uniformity of heat conduction can be ensured, the heat conduction rate of the electrode group is increased, and the thermal runaway situation caused by heat accumulation in the battery under the conditions of heat box, thermal spread and short circuit is avoided, improving the safety performance of the battery. And the elastic heat dissipation part 12 can adjust its actual position according to actual needs. For example, the elastic heat dissipation part 12 can be arranged in the gap of the connection area 13, such as the welding area, and within the inner circle of the welding area. Moreover, the size of the elastic heat dissipation part 12 can be coordinated with the design of the connection area 13, such as the welding area, according to actual needs.
[0045] Among them, for the connecting piece body 11, it is in close contact with the electrode group and is preferably connected by laser welding. Through the reasonable design of the hollow area, the elastic heat dissipation part 12 is staggered from the connection area 13, such as the welding area, and will not affect each other. Thus, the overcurrent deficiency caused by insufficient welding is avoided. At the same time, the connecting piece body 11 part has the ability of rapid heat dissipation. When the battery generates heat, the heat is quickly conducted to the negative metal cover plate for heat exchange with the outside, thereby improving the safety performance of the battery.
[0046] Among them, for the inclined assembly part 14, the inclined assembly part 14 can be laser welded to the housing. It presents a certain angle with the connecting piece main body 11, which is convenient for it to fit against the inner wall of the housing during welding, avoiding problems such as welding explosion points due to insufficient fitting. The included angle α between it and the connecting piece main body 11 in the thickness direction can be adjusted according to the difference in the material strength of the connecting piece, and its range is 0° < α ≤ 45°. Moreover, the length of the inclined assembly part 14 is selected between 0 and 5 mm.
[0047] Embodiment 2 Embodiment 2 of the present application further provides a battery, including the battery connecting piece 1 described in Embodiment 1 above. Therefore, it has all the beneficial technical effects of the battery connecting piece 1, and the same technical features and beneficial effects will not be elaborated here.
[0048] In this embodiment, preferably, the battery further includes a housing, a pole group, and a metal cover plate; among them, the metal cover plate seals the pole group in the housing; the connecting piece main body 11 is arranged at one end of the pole group and is connected to the pole ear of the pole group; the connecting piece main body 11 is formed with an elastic heat dissipation part 12, and the elastic heat dissipation part 12 extends to the metal cover plate and is in contact with the metal cover plate for conducting heat. According to the structure described above, the elastic heat dissipation part 12 of the battery connecting piece 1 is in close contact with the pole group, and preferably, they are connected by laser welding. Through the reasonable design of the hollow area of the connecting piece main body 11, the effective welding area of the connecting piece main body 11 is maximally guaranteed, and the connecting piece main body 11 part has the ability of rapid heat dissipation. When the battery generates heat, the heat is rapidly conducted to the negative metal cover plate for heat exchange with the outside, thereby improving the battery safety performance.
[0049] Furthermore, preferably, the aforementioned metal cover plate is a negative metal cover plate, and the housing and the connecting piece of the battery are negatively charged as a whole. Of course, it is not limited to this, and the specific charging situation of the metal cover plate can also be selected according to actual needs. That is to say, the battery connecting piece 1 provided in the present application can also be assembled with other types of metal cover plates, specifically according to the actual design.
[0050] It should be noted that: when the battery connecting piece 1 is in contact with the housing of the battery, since the housing can only carry one polarity of electricity, and thus it can only be in contact with one polarity of metal cover plate, such as the negative metal cover plate, and cannot be in contact with both the negative metal cover plate and the positive metal cover plate at the same time. In this case, it is necessary to ensure that only the metal cover plate at one open end of the housing is provided with the aforementioned battery connecting piece 1. When the battery connecting piece 1 is not in contact with the housing, both the negative metal cover plate and the positive metal cover plate of the battery can be provided with the battery connecting piece 1 provided in the present application.
[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit them. Although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features. These modifications or replacements 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 battery connection piece is applied to a battery. The battery includes a housing, a pole group, and a metal cover plate. The metal cover plate seals the pole group in the housing. It is characterized in that, The battery connecting piece includes a connecting piece body which is used to be installed at one end of the electrode group and is connected to the tab of the electrode group; the connecting piece body is formed with an elastic heat dissipation part, and the elastic heat dissipation part is used to extend to the metal cover plate and contact the metal cover plate for conducting heat.
2. The battery connection piece according to claim 1, wherein, The elastic heat dissipation part is a structure protruding from the connecting piece body formed by cutting and lifting a corresponding position of the connecting piece body; or The elastic heat dissipation part and the connecting piece body are of a split structure and are assembled and connected together.
3. The battery connection piece according to claim 1, characterized in that, The number of the elastic heat dissipation parts is multiple, and they are sequentially arranged at intervals along the circumferential direction of the connecting piece body.
4. The battery connection piece according to claim 1, characterized in that, The connecting piece body is formed with multiple connecting areas, and any one of the connecting areas is connected to the tab of the electrode group, and the multiple connecting areas are sequentially arranged at intervals along the circumferential direction of the connecting piece body.
5. The battery connection piece according to claim 4, characterized in that, The elastic heat dissipation part is arranged inside the inner ring of the annular structure surrounded by the multiple connecting areas; or At least one elastic heat dissipation part is arranged between at least one group of two adjacent connecting areas.
6. The battery connection piece according to claim 4, characterized in that, The connecting area is fan-shaped.
7. The battery connection piece according to claim 1, wherein, The outer edge of the connecting piece body is formed with an inclined assembly part which is inclined with respect to the thickness direction of the connecting piece body, and the inclined assembly part is used to abut against the inside of the housing.
8. The battery connection piece according to claim 7, characterized in that, The inclination angle of the inclined assembly part with respect to the thickness direction of the connecting piece body is ɑ, and 0° < ɑ ≤ 45°; and / or Along the direction from the center of the connecting piece body towards the outside, the length of the inclined assembly part is b, and 0 < b ≤ 5 mm; and / or The inclined assembly part is an annular structure.
9. The battery connection piece according to any one of claims 1 to 8, characterized in that, The connecting piece body is formed with a liquid injection through hole.
10. A battery, characterized in that, It includes a housing, an electrode group, a metal cover plate and the battery connecting piece according to any one of claims 1 to 9; wherein, the metal cover plate seals the electrode group in the housing; the connecting piece body is arranged at one end of the electrode group and is connected to the tab of the electrode group; the connecting piece body is formed with an elastic heat dissipation part, and the elastic heat dissipation part extends to the metal cover plate and contacts the metal cover plate for conducting heat.