Cover plate and battery

Abstract

Cover plate, characterized in that it has the following features: a cover plate body (1) which is provided with a connection hole, wherein the cover plate body (1) has a first metal layer (101) and a second metal layer (102), wherein the first metal layer (101) and the second metal layer (102) are arranged stacked in a thickness direction of the cover plate, wherein a hardness of the first metal layer (101) is greater than a hardness of the second metal layer (102) and a thermal conductivity of the second metal layer is greater than a thermal conductivity of the first metal layer (101); a connection (2) which is at least partially located in the connection hole; an annular element (103) arranged in such a way as to be insulated from the connection (2), the annular element (103) comprising a limiting section (1031), a welded section (1032) and a transition section (1033), the limiting section (1031) being configured to limit the connection (2), the welded section (1032) being connected to the second metal layer (102) by welding, the transition section (1033) being configured to connect the limiting section (1031) and the welded section (1032), and a material of the annular element (103) being the same as a material of the second metal layer (102); where the ratio of the thickness T1 of the first metal layer (101) to the thickness T2 of the second metal layer (102) is 0.1-12.5.

Description

TECHNICAL AREA

[0001] The present utility model relates to the field of battery technology and specifically relates to a cover plate and a battery. BACKGROUND

[0002] A battery is a device that converts chemical energy into electrical energy. The battery consists of one or more battery cells, each containing a positive electrode, a negative electrode, and an electrolyte. When the battery is connected to a circuit, chemical reactions occur within the battery cells, causing electrons to flow from the negative electrode to the positive electrode, thereby generating an electric current.

[0003] Currently, batteries can be classified into two main categories: primary batteries and secondary batteries. Secondary batteries are also known as rechargeable batteries and can restore their charge after being discharged. Common types of secondary batteries include lead-acid batteries, nickel-cadmium batteries, nickel-metal hydride batteries, and lithium-ion batteries. Lithium-ion batteries are widely used in smartphones, laptops, and electric vehicles due to their high energy density and light weight.

[0004] A lithium-ion battery typically contains a casing, a cover plate, and a terminal. The cover plate is generally made of aluminum. Aluminum has relatively low strength. If the terminal is welded to the casing, the overall strength of the cover plate is also relatively weak. This can easily lead to a terminal connection failure, which in turn reduces the battery's current transfer efficiency. This can cause the battery to operate unstably and negatively impact its performance. SUMMARY

[0005] In view of this, the present utility model provides a cover plate and a battery to solve the problem that a cover plate made of an aluminum material can easily lead to a connection fault.

[0006] According to a first aspect, the present utility model provides a cover plate comprising: a cover plate body provided with a connection hole, wherein the cover plate body comprises a first metal layer and a second metal layer, the first metal layer and the second metal layer being stacked in a thickness direction of the cover plate, wherein the hardness of the first metal layer is greater than the hardness of the second metal layer and the thermal conductivity of the second metal layer is greater than the thermal conductivity of the first metal layer; a connection being arranged at least partially in the connection hole;an annular element arranged to be isolated from the connection, the annular element comprising a boundary section, a weld section, and a transition section, the boundary section being configured to delimit the connection, the weld section being joined to the second metal layer by welding, the transition section being configured to connect the boundary section and the weld section, and a material of the annular element being the same as a material of the second metal layer; wherein a ratio of the thickness T1 of the first metal layer to the thickness T2 of the second metal layer is 0.1–12.5.

[0007] According to a second aspect, the present utility model also provides a battery comprising: the aforementioned cover plate; a housing with an opening for attaching the cover plate; a battery cell arranged in the housing.

[0008] Advantageous effects: The cover plate body consists of two different metals, resulting in relatively high overall strength. This prevents connection failures when the terminal is welded to the housing, thus ensuring battery performance. The annular element is made of the same material as the second metal layer, meaning their melting points are the same, which facilitates welding the annular element to the second metal layer. Simultaneously, the thermal conductivity of the second metal layer is higher than that of the first. During battery operation, the heat generated by the terminal is transferred through the annular element to the second metal layer, allowing the heat from the terminal to be quickly transferred to the cover plate, which in turn dissipates the heat away from the terminal.This can prevent overheating of the connector, thus avoiding problems such as performance degradation, thermal runaway and reduced lifespan caused by excessively high temperatures.

[0009] The ratio of the thickness T1 of the first metal layer to the thickness T2 of the second metal layer, which is in the range of 0.1-12.5, can not only ensure a heat dissipation effect and prevent thermal runaway of the battery, but also ensures structural strength of the cover plate and provides an effective connection between the ring-shaped element and the cover plate body, thereby improving the reliability and stability of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] To more clearly explain the technical solutions according to the specific embodiments of the present utility model or in the prior art, the drawings that must be used to describe the specific embodiments or the prior art are briefly presented below. Obviously, the drawings in the following description are some embodiments of the present utility model. Furthermore, a person skilled in the art can derive other drawings from these without creative effort; they show: Fig. 1 a perspective view of a battery of an embodiment of the present utility model; Fig. 2 a top view of the in Fig. 1 battery shown; Fig. 3 a sectional view along a line AA of the in Fig. 2 batteries shown; Fig. 4 a schematic structural view of a right side of the in Fig. 3 shown connection; Fig. 5 a schematic structural view of a left side of the in Fig. 3 shown connection; and Fig. 6 a partial sectional view of another cover plate of a battery of an embodiment of the present utility model. Reference symbol:

[0011] 1, cover plate body; 101, first metal layer; 1011, recessed section; 102, second metal layer; 1021, projecting step; 103, annular element; 1031, boundary section; 1032, weld section; 1033, transition section; 2, connection; 201, protruding ring; 3, upper insulating element; 301, circumferential section; 4, Housing. DETAILED DESCRIPTION OF THE EXECUTION FORMS

[0012] To clarify the tasks, technical solutions, and advantages of the embodiments of this utility model, the technical solutions according to the embodiments of this utility model are described clearly and completely below with reference to the drawings of the embodiments of this utility model. Obviously, the described embodiments are a subset of the embodiments of this utility model and not all embodiments. Based on the embodiments of this utility model, all other embodiments that could be obtained by a person skilled in the art without creative effort are intended to fall within the scope of protection of this utility model.

[0013] The embodiments of the present utility model are described below with regard to Fig. 1 to Fig. 6 described.

[0014] According to one embodiment of the present utility model, a cover plate is provided, comprising: a cover plate body 1, a connection 2, and an annular element 103. The cover plate body 1 is provided with a connection hole. The cover plate body 1 comprises a first metal layer 101 and a second metal layer 102. The first metal layer 101 and the second metal layer 102 are stacked in the thickness direction of the cover plate. The hardness of the first metal layer 101 is greater than the hardness of the second metal layer 102. The thermal conductivity of the second metal layer 102 is greater than that of the first metal layer 101. The connection 2 is at least partially located in the connection hole. The annular element 103 is arranged such that it is insulated from the connection 2.The annular element 103 comprises a boundary section 1031, a welded section 1032, and a transition section 1033. The boundary section 1031 is configured to define the connection 2. The welded section 1032 is connected to the second metal layer 102 by welding. The transition section 1033 is configured to connect the boundary section 1031 and the welded section 1032, wherein one material of the annular element 103 is the same as one material of the second metal layer 102, where the ratio of the thickness T1 of the first metal layer 101 to the thickness T2 of the second metal layer 102 is 0.1–12.5.

[0015] By using the cover plate of the present embodiment, the cover plate body 1 consists of two different metals, therefore the overall strength of the cover plate is relatively high. This, in turn, avoids the possibility of a connection failure at terminal 2 when terminal 2 is welded to the housing 4, thus ensuring the battery's performance. The material of the annular element 103 is the same as the material of the second metal layer 102, therefore their melting points are the same, which facilitates welding the annular element 103 to the second metal layer 102. At the same time, the thermal conductivity of the second metal layer 102 is greater than that of the first metal layer 101.During battery use, the heat generated by terminal 2 is transferred by the annular element 103 to the second metal layer 102, so that the heat from terminal 2 is quickly transferred to the cover plate, which in turn dissipates the heat for terminal 2. This prevents overheating of terminal 2, thus avoiding problems such as performance degradation, thermal runaway, and reduced lifespan caused by excessively high temperatures. Furthermore, the thickness T1 of the first metal layer 101 is a vertical dimension of the first metal layer 101 in [missing information]. Fig. 4, while the thickness T2 of the second metal layer 102 is a vertical dimension of the second metal layer 102 in Fig. 4. If the ratio of the thickness T1 of the first metal layer 101 to the thickness T2 of the second metal layer 102 is too small, the strength of the cover plate body 1 is low, which can easily lead to failure of the weld joint between the annular element 103 and the cover plate body 1, resulting in damage to a terminal assembly. If the ratio of the thickness T1 of the first metal layer 101 to the thickness T2 of the second metal layer 102 is too large, this condition is unfavorable for heat dissipation of the terminal and the cover plate, which can easily lead to heat buildup in the terminal, which in turn leads to thermal runaway of the battery and impairs the battery charging speed.

[0016] Therefore, the ratio of the thickness T1 of the first metal layer 101 to the thickness T2 of the second metal layer 102, which is in the range of 0.1-12.5, not only ensures a heat dissipation effect and prevents thermal runaway of the battery, but also ensures structural strength of the cover plate and provides an effective connection between the ring-shaped element 103 and the cover plate body 1, thereby improving the reliability and stability of the battery.

[0017] It should be mentioned that one connection arrangement includes the connection 2 and the ring-shaped element 103.

[0018] According to one embodiment, the first metal layer 101 is arranged above the second metal layer 102, as shown in Fig. 4 and Fig. Figure 5 shows that the first metal layer has a greater hardness and is arranged over the second metal layer 102, so that the cover plate body 1 has great structural strength, can better withstand external shock and pressure, and reduces the risk of damage to internal parts of the battery due to collision or dropping.

[0019] Furthermore, the ratio of the thickness T1 of the first metal layer 101 to the thickness T2 of the second metal layer 102 is 0.1-12. Because the thermal conductivity of the first metal layer 101 is lower, it is disadvantageous for the heat dissipation of terminal 2 that the first metal layer 101 is located on top. This easily leads to a heat accumulation at terminal 2, which in turn causes thermal runaway of the battery and impairs the battery's charging rate.

[0020] Therefore, a T1 / T2 ratio in the range of 0.1–12 is advantageous for heat dissipation from terminal 2 and the cover plate, thus improving the battery's charging speed; furthermore, a T1 / T2 ratio in the range of 0.1–12 ensures the structural strength of the cover plate body 1, improving the overall performance, safety, and service life of the battery. Preferably, T1 / T2 is 0.1, 0.5, 0.8, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12.

[0021] It can be seen that, according to a further embodiment, the first metal layer 101 is arranged below the second metal layer 102, as in Fig. Figure 6 shows that the second metal layer 102 has a higher thermal conductivity. Positioning the second metal layer 102 above the first metal layer 101 is advantageous for heat dissipation from the terminal 2 and the cover plate, thus improving the battery's charging speed. Furthermore, the ratio of the thickness T1 of the first metal layer 101 to the thickness T2 of the second metal layer 102 is 0.15–12.5. The second metal layer 102 has a lower hardness, resulting in a lower structural strength for the cover plate body 1. The cover plate body 1 is less resistant to external impacts and pressure, increasing the risk of damage to the battery's internal components due to collisions or drops. Therefore, the T1 / T2 ratio, which is in the range of 0.15–12.5, ensures the structural strength of the cover plate body 1.The cover plate body 1 can better withstand external shock and pressure, reducing the risk of damage to the internal parts of the battery due to collision or dropping, and improving the overall performance, safety and service life of the battery.

[0022] According to one embodiment, the second metal layer 102 projects beyond the first metal layer 101 on one side near the annular element 103 to form a projecting step 1021, wherein the weld section 1032 is connected to a top surface of the projecting step 1021 by welding. The weld area between the weld section 1032 and the projecting step 1021 is larger. This can significantly improve the weld strength between the weld section 1032 and the second metal layer 102, enhance the joint reliability, and also facilitate welding, thus reducing welding difficulty.

[0023] Furthermore, in a longitudinal direction of the cover plate, the length L1 of the aforementioned step 1021 is 0.4 mm–8 mm. The length L1 of the aforementioned step 1021 is a horizontal dimension of the aforementioned step 1021 in Fig. 5. If the length L1 of the preceding step 1021 is too short, the weld area between the weld section 1032 and the second metal layer 102 will be smaller, which will impair the weld strength and consequently fail to ensure adequate heat dissipation from the terminal 2. If the length L1 of the preceding step 1021 is too long, the terminal 2 and the cover plate may overlap slightly, which could easily cause an insulation fault.

[0024] Therefore, the length L1 of the preceding stage 1021, which is in the range of 0.4 mm–8 mm, ensures, on the one hand, that the size of a weld area between the weld section 1032 and the first metal layer 101 is adequate, thus ensuring weld strength and being advantageous for the heat dissipation of the connection 2; on the other hand, the length L1 of the preceding stage 1021, in the range of 0.4 mm–8 mm, avoids an overlap between the connection 2 and the cover plate, thus ensuring an insulating effect between the cover plate and the connection 2.

[0025] Preferably, L1 is 0.4 mm, 0.6 mm, 0.8 mm, 1 mm, 1.2 mm, 2 mm, 2.4 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm or 8 mm.

[0026] According to one embodiment, in the thickness direction of the cover plate, the top surface of the weld section 1032 is lower than the top surface of the first metal layer 101. After the weld section 1032 has been welded to the cover plate body 1, a weld seam and weld slag are formed. This arrangement prevents the weld seam and weld slag from protruding from the top surface of the cover plate, ensuring that no interference occurs when a battery pack is assembled.

[0027] Furthermore, in the thickness direction of the cover plate, there is a height difference T5 between the top of the weld section 1032 and the top of the first metal layer 101 of 0.2 mm–2.5 mm. If the height difference T5 is too small, it cannot be ensured that the weld and weld slag will not protrude from the top of the cover plate, which could easily interfere with other components during battery pack assembly. If the height difference T5 is too large, the thickness of the recessed section 1011 will be too thin, which will compromise the structural strength of the cover plate body 1.

[0028] Therefore, the height difference T5 in the range of 0.2 mm-2.5 mm not only ensures that the weld seam and weld slag do not protrude from the top of the cover plate, thus ensuring that there is no interference with other components when the battery pack is assembled, but also that the thickness of the recessed section 1011 is adequate, ensuring the structural strength of the cover plate body 1 and improving the overall performance, safety and service life of the battery.

[0029] Preferably, T5 is 0.2 mm, 0.4 mm, 0.6 mm, 0.8 mm, 1 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8 mm, 2 mm or 2.5 mm.

[0030] According to one embodiment, a section of the first metal layer 101 near the weld section 1032 has a recessed section 1011. The provision of the recessed section 1011 can reduce the partial thickness of the first metal layer 101, which achieves rapid heat dissipation from the terminal 2, thereby preventing thermal runaway of the battery.

[0031] According to one embodiment, T1 is 0.2 mm–2.5 mm, while T2 is 0.2 mm–2 mm. If the thickness of T1 is too large or the thickness of T2 is too small, this is unfavorable for the heat dissipation of the terminal and the cover plate, easily causing heat buildup in the terminal, which in turn leads to thermal runaway of the battery and impairs the battery charging speed. If the thickness of T1 is too small or the thickness of T2 is too large, the strength of the cover plate body 1 is low, easily causing failure of the weld joint between the annular element 103 and the cover plate body 1, resulting in damage to the terminal assembly.

[0032] Therefore, T1, which is in the range of 0.2 mm-2.5 mm, and T2, which is in the range of 0.2 mm-2 mm, can not only ensure a heat dissipation effect and prevent thermal runaway of the battery, but also ensure structural strength of the cover plate and an effective connection between the annular element 103 and the cover plate body 1, thereby improving the reliability and stability of the battery.

[0033] Preferably, T1 is 0.2 mm, 0.3 mm, 0.4 mm, 0.8 mm, 1 mm, 1.2 mm, 1.6 mm, 1.8 mm, 2 mm, or 2.5 mm, while T2 is 0.2 mm, 0.3 mm, 0.4 mm, 0.8 mm, 1 mm, 1.2 mm, 1.6 mm, 1.8 mm, or 2 mm. According to one embodiment, the thickness T3 of the annular element 103 is 0.2 mm to 2 mm. If the thickness T3 of the annular element 103 is greater, the weight increases, the cost increases, and more space is required. If the thickness T3 of the annular element 103 is less, sufficient mechanical support cannot be provided, especially if it is subjected to a large shock or vibration, which can lead to loosening or damage to the connection.

[0034] Therefore, the thickness T3 of the ring-shaped element 103, which is in the range of 0.2 mm-2 mm, can on the one hand provide sufficient mechanical support, ensuring that a connection between the connection 2 and the cover plate body 1 is stronger; on the other hand, the thickness T3 of the ring-shaped element 103 in the range of 0.2 mm-2 mm does not significantly increase the weight or take up too much space, thus ensuring space utilization.

[0035] Preferably, T3 is 0.2 mm, 0.3 mm, 0.4 mm, 0.8 mm, 1 mm, 1.2 mm, 1.6 mm, 1.8 mm, or 2 mm. According to one embodiment, the material of the first metal layer 101 is steel, while the material of the second metal layer 102 is aluminum. Steel has good structural strength, while aluminum has good heat dissipation performance, thus ensuring the structural strength and heat dissipation performance of the cover plate body 1.

[0036] Furthermore, T1 is 0.2 mm-2 mm, while T2 is 0.2 mm-1.6 mm, i.e., T1 and T2 are in suitable ranges, so that the material properties of the first metal layer 101 and the second metal layer 102 are more optimal, which improves the structural strength and heat dissipation performance of the cover plate body 1.

[0037] According to one embodiment, an outer wall of a lower end of the connection 2 has an outwardly projecting ring 201, a section of the limiting section 1031 extends over the projecting ring 201, and a distance L2 between an outer circumferential surface of the projecting ring 201 and an inner circumferential surface of the limiting section 1031 is 0.1 mm–5 mm, as shown in Fig. 4 and Fig. 5 is shown.

[0038] If the outer diameter of the projecting ring 201 is a fixed value, and L2 is smaller, the limiting capability of the limiting section 1031 is further limited, as it cannot effectively press against the terminal 2. If L2 is larger, the limiting section 1031 is located close to the terminal 2, and the limiting section easily penetrates an upper insulating element 3 to touch the terminal 2 and conduct electricity, which poses a greater safety risk.

[0039] Therefore, the distance L2 between the outer circumferential surface of the protruding ring 201 and the inner circumferential surface of the limiting section 1031, which is in the range of 0.1 mm-5 mm, not only ensures the limiting capability of the limiting section 1031, but also ensures that there is a certain distance between the limiting section 1031 and the terminal 2, thereby improving the safety of the battery.

[0040] Preferably, L2 is 0.1 mm, 0.2 mm, 0.8 mm, 1 mm, 1.2 mm, 1.6 mm, 1.8 mm, 2 mm, 2.2 mm, 2.4 mm, 3 mm, 3.6 mm, 4 mm or 5 mm.

[0041] According to one embodiment, the ratio of the thickness T3 of the annular element 103 to the thickness T2 of the second metal layer 102 is 0.1-10, as shown in Fig. 4 and Fig. 5 is shown.

[0042] If the ratio of the thickness T3 of the annular element 103 to the thickness T2 of the second metal layer 102 is smaller, the strength of a weld section between the annular element 103 and the second metal layer 102 is also lower, a weld point between the annular element 103 and the second metal layer 102 is easily damaged due to vibration or shock, and the limiting capability of the limiting section 1031 of the annular element 103 with a smaller thickness is limited, and it cannot effectively press on the connection 2.If the ratio of the thickness T3 of the annular element 103 to the thickness T2 of the second metal layer 102 is larger, the strength of a weld section between the annular element 103 and the second metal layer 102 is also lower, a weld joint between the annular element 103 and the second metal layer 102 is easily damaged by vibration or shock, and the limiting capability of the annular element 103 is slightly impaired by the structural strength of the weld joint between the annular element 103 and the second metal layer 102.

[0043] Therefore, the ratio of the thickness T3 of the annular element 103 to the thickness T2 of the second metal layer 102, which is in the range of 0.1-10, can not only ensure the structural strength of the weld section between the annular element 103 and the second metal layer 102, but also ensure effective pressure on the terminal 2, which improves the overall reliability of the battery.

[0044] Preferably, T3 / T2 is 0.1, 0.2, 0.6, 0.8, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. Furthermore, the annular element 103 and the second metal layer 102 are formed separately. The separate processing of the annular element 103 and the second metal layer 102, followed by welding them together, reduces processing difficulty and thus saves costs. According to one embodiment, the cover plate also includes an upper insulating element 3, as shown in Fig. 4 and Fig.Figure 5 shows the upper insulating element 3 being arranged between the terminal 2 and the annular element 103, and the thickness T4 of a section of the upper insulating element 3 located between the limiting section 1031 and the projecting ring 201 being 0.2 mm–2 mm. The upper insulating element 3 employs an insulating material capable of isolating the terminal 2 from the cover plate body 1, preventing a short circuit between the terminal 2 and the cover plate body 1, and ensuring electrical insulation between the terminal 2 and the cover plate body 1.

[0045] If the thickness T4 of the section of the upper insulating element 3 located between the limiting section 1031 and the projecting ring 201 is smaller, the terminal 2 and the limiting section 1031 may easily short-circuit due to vibration or shock, posing a greater safety risk. If the thickness T4 of the section of the upper insulating element 3 located between the limiting section 1031 and the projecting ring 201 is larger, the height of the limiting section 1031 and the overall thickness of the upper insulating element 3 are increased, occupying a large vertical space, which in turn reduces the space utilization rate in a battery pack.

[0046] Therefore, the thickness T4 of the section of the upper insulating element 3, located between the limiting section 1031 and the protruding ring 201, which is in the range of 0.2 mm–2 mm, can not only ensure the insulation between the terminal 2 and the limiting section 1031, thus preventing a short circuit between the terminal 2 and the cover plate body 1, but also controls the height of the limiting section 1031 and the overall thickness of the upper insulating element 3, thus requiring less space and improving the space utilization rate of the battery pack.

[0047] Preferably, T4 is 0.2 mm, 0.3 mm, 0.4 mm, 0.8 mm, 1 mm, 1.2 mm, 1.6 mm, 1.8 mm or 2 mm.

[0048] According to one embodiment, an upper surface of the upper insulating element 3 extends along an outer surface of the limiting section 1031 to form a circumferential section 301 that surrounds the limiting section 1031. The upper insulating element 3 encloses the limiting section 1031, effectively confining it and preventing it from being displaced or deformed during use. This helps ensure that a stable relative position between the battery terminal 2 and other components is maintained, thus preventing loosening of the connection caused by vibration or shock.Specifically, the cross-sectional shape of the ring-shaped element 103 is similar to a "Z" shape, which not only facilitates attachment to the second metal layer 102, but also facilitates pressing onto the terminal 2, making the structure of the ring-shaped element 103 simple and easy to implement.

[0049] It should be noted that the units T1, T2, T3, L1, L2, T4, and T5 are all in mm. According to the embodiments of the present utility model, a battery is also provided, comprising the following: the aforementioned cover plate, a housing 4, and a battery cell. The housing 4 has an opening for attaching the cover plate. The battery cell is arranged within the housing 4.

[0050] According to one embodiment, the housing 4 is made of the same material as the first metal layer 101, and the housing 4 is connected to the first metal layer 101 of the cover plate by welding. The housing 4 and the first metal layer 101 have the same melting point, which facilitates welding between the housing 4 and the cover plate, resulting in an effective connection between the housing 4 and the cover plate.

[0051] Furthermore, the material of the first metal layer 101 is steel, the material of the housing 4 is steel, and the material of the second metal layer 102 is aluminum. Both the housing 4 and the first metal layer 101 are made of steel. Steel offers superior strength, giving the cover plate body 1 and the housing 4 high structural strength, better resistance to external impact and pressure, and reducing the risk of damage to the battery's internal components due to collisions or drops. The second metal layer 102 is made of aluminum. Aluminum offers superior heat dissipation, which is beneficial for heat dissipation from the terminal 2 and the cover plate, thus improving the battery's charging speed.

[0052] Although the embodiments of the present utility model have been described with respect to the drawings, a person skilled in the art can make various modifications and variations without deviating from the inventive concept and scope of protection of the present utility model. Such modifications and variations shall fall within the scope of protection defined by the appended claims.

Claims

[1] Cover plate, characterized by that it exhibits the following: a cover plate body (1) which is provided with a connection hole, wherein the cover plate body (1) has a first metal layer (101) and a second metal layer (102), wherein the first metal layer (101) and the second metal layer (102) are arranged stacked in a thickness direction of the cover plate, wherein a hardness of the first metal layer (101) is greater than a hardness of the second metal layer (102) and a thermal conductivity of the second metal layer is greater than a thermal conductivity of the first metal layer (101); a connection (2) which is at least partially located in the connection hole; an annular element (103) arranged in such a way as to be insulated from the connection (2), the annular element (103) comprising a limiting section (1031), a welded section (1032) and a transition section (1033), the limiting section (1031) being configured to limit the connection (2), the welded section (1032) being connected to the second metal layer (102) by welding, the transition section (1033) being configured to connect the limiting section (1031) and the welded section (1032), and a material of the annular element (103) being the same as a material of the second metal layer (102); where the ratio of the thickness T1 of the first metal layer (101) to the thickness T2 of the second metal layer (102) is 0.1-12.

5. [2] Cover plate according to claim 1, characterized by , that the first metal layer (101) is arranged above the second metal layer (102). [3] Cover plate according to claim 2, characterized by , that the ratio of the thickness T1 of the first metal layer (101) to the thickness T2 of the second metal layer (102) is 0.1-12. [4] Cover plate according to claim 2, characterized by , that on one side near the ring-shaped element (103) the second metal layer (102) projects beyond the first metal layer (101) to be provided with a projecting step (1021), and the welded section (1032) is connected to a top of the projecting step (1021) by welding. [5] Cover plate according to claim 4, characterized by , that in a longitudinal direction of the cover plate a length L1 of the protruding step (1021) is 0.4 mm-8 mm. [6] Cover plate according to claim 2, characterized by , that in the thickness direction of the cover plate, a top surface of the weld section (1032) is lower than a top surface of the first metal layer (101). [7] Cover plate according to claim 6, characterized by, that in the thickness direction of the cover plate there is a height difference T5 between the top of the weld section (1032) and the top of the first metal layer (101) of 0.2 mm-2.5 mm. [8] Cover plate according to claim 1, characterized by , that the first metal layer (101) is arranged below the second metal layer (102). [9] Cover plate according to claim 8, characterized by , that the ratio of the thickness T1 of the first metal layer (101) to the thickness T2 of the second metal layer (102) is 0.15-12.

5. [10] Cover plate according to claim 1, characterized by , that T1 is 0.2 mm-2.5 mm. [11] Cover plate according to claim 1, characterized by , that T2 is 0.2 mm-2 mm. [12] Cover plate according to claim 1, characterized by , that a thickness T3 of the ring-shaped element (103) is 0.2 mm-2 mm. [13] Cover plate according to claim 1, characterized by, that a material of the first metal layer (101) is steel and a material of the second metal layer (102) is aluminium. [14] Cover plate according to claim 13, characterized by , that T1 is 0.2 mm-2 mm and T2 is 0.2 mm-1.6 mm. [15] Cover plate according to claim 1, characterized by , that the ratio of the thickness T3 of the ring-shaped element (103) to the thickness T2 of the second metal layer (102) is 0.1-10. [16] Cover plate according to claim 1, characterized by , that an outer wall of a lower end of the connection (2) has an outwardly projecting ring (201), a section of the boundary section (1031) extends over the projecting ring (201) and a distance L2 between an outer circumferential surface of the projecting ring (201) and an inner circumferential surface of the boundary section is 0.1 mm-5 mm. [17] Cover plate according to claim 16, characterized by, that the cover plate further comprises an upper insulating element (3), the upper insulating element (3) is arranged between the connection (2) and the annular element (103) and the thickness T4 of a section of the upper insulating element (3) located between the boundary section (1031) and the projecting ring (201) is 0.2 mm-2 mm. [18] Cover plate according to claim 17, characterized by , that a top surface of the upper insulating element (3) extends along an outside surface of the boundary section (1031) to form a circumferential section (301) that surrounds the boundary section (1031). [19] Battery, characterized by that it exhibits the following: the cover plate according to any one of claims 1 to 18; a housing (4) with an opening for attaching the cover plate; a battery cell which is arranged in the housing (4). [20] Battery according to claim 19, characterized by, that a material of the housing (4) is the same as a material of the first metal layer (101) and that the housing (4) is connected to the first metal layer (101) of the cover plate by welding. [21] Battery according to claim 20, characterized by , that the material of the first metal layer (101) is steel, the material of the casing (4) is steel and the material of the second metal layer (102) is aluminium.

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