Cover plate assembly and battery

Abstract

The invention discloses a cover plate assembly and a battery, and relates to the technical field of batteries, the cover plate assembly comprises a pole, the pole is divided into a first metal layer and a second metal layer along the thickness direction, the first metal layer is located at the front side of the second metal layer, and the melting point of the first metal layer is smaller than that of the second metal layer; the heat conduction rate of the second metal layer is larger than the heat conduction rate of the first metal layer and larger than the heat conduction rate of the pressing plate, so that the second metal layer can rapidly take away heat generated by welding, overheating softening of the insulating part is avoided, the pressing plate and the peripheral side of the first metal layer are welded and fixed, and a welding mark is formed between the pressing plate and the first metal layer. The thickness of the first metal layer is H1, the thickness of the second metal layer is H2, the depth of the welding mark is H3, and the parameters meet the preset relation, so that the cover plate assembly can enable the welding strength to be matched with the heat conduction effect, and the cover plate assembly has enough welding strength and can also achieve the expected heat conduction effect.

Description

Technical Field

[0001] The present invention relates to the technical field of power batteries, and in particular to a cover plate assembly and a battery. Background Art

[0002] A power battery is a battery that provides power for tools. It generally includes a metal shell, a battery cell disposed in the metal shell, and a cover assembly fixed to the top of the metal shell. The cover assembly is provided with a pole structure, which is responsible for the power transmission of the power battery. Therefore, the stability of the pole structure itself affects the performance of the power battery.

[0003] At present, the existing cover plate assembly generally includes a cover plate, a pressure plate, a pole and an insulating member, wherein the pole is inserted into the cover plate, and the pressure plate and the insulating member are sleeved on the pole. The pressure plate is connected and fixed to the pole by welding, so that the pole can neither be horizontally twisted nor axially moved. The insulating member is arranged between the pressure plate and the cover plate to isolate the electrical conduction between the cover plate and the pressure plate.

[0004] However, when the pole and the pressure plate are welded, the heat generated by welding is very high, which can easily cause the insulating parts to soften and cause insulation failure. Summary of the invention

[0005] The object of the present invention is to provide a cover plate assembly and a battery, which improve the structural arrangement of the pole so that the pole can promptly take away the heat generated by welding, thereby avoiding the problem of insulation failure caused by softening of the insulating part.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A cover plate assembly, comprising:

[0008] A cover plate, wherein the cover plate is provided with mounting holes that penetrate the cover plate from front to back along the thickness direction thereof;

[0009] A pole, the pole being passed through the mounting hole;

[0010] A pressing plate, the pressing plate is sleeved on the pole;

[0011] an insulating member, the insulating member being disposed between the pressing plate and the cover plate to separate the pressing plate from the cover plate;

[0012] The pole is divided into a first metal layer and a second metal layer along the thickness direction thereof, the first metal layer is located in front of the second metal layer, the melting point of the first metal layer is lower than the melting point of the second metal layer, the thermal conductivity of the second metal layer is higher than the thermal conductivity of the first metal layer, and is higher than the thermal conductivity of the pressing plate; and

[0013] The pressing plate is welded and fixed to the outer peripheral side of the first metal layer, so that a welding mark is formed between the pressing plate and the first metal layer; and

[0014] The thickness of the first metal layer is H1, the thickness of the second metal layer is H2, the depth of the weld mark is H3, and the above parameters satisfy:

[0015]

[0016] In some embodiments, the thickness H1 of the first metal layer satisfies: 2≤H1≤4 mm.

[0017] In some embodiments, the thickness H2 of the second metal layer satisfies: 1≤H2≤2 mm.

[0018] In some embodiments, the depth H3 of the weld mark satisfies: 0.4≤H3≤2mm.

[0019] In some embodiments, the rear side of the second metal layer is recessed toward the front side along the thickness direction thereof to form a recessed portion.

[0020] In some embodiments, the depth of the recessed portion is H4, and the depth H4 of the recessed portion and the thickness H2 of the second metal layer satisfy:

[0021]

[0022] In some embodiments, the depth H4 of the recessed portion satisfies: 1≤H4≤4 mm.

[0023] In some embodiments, the interface between the first metal layer and the second metal layer is flush with the rear side of the pressing plate, and the thickness H1 of the first metal layer, the thickness H2 of the second metal layer, and the depth H3 of the weld mark satisfy:

[0024]

[0025] In some embodiments, the interface between the first metal layer and the second metal layer is located at the front side of the rear side of the pressing plate, and the thickness H1 of the first metal layer, the thickness H2 of the second metal layer, and the depth H3 of the weld mark satisfy:

[0026]

[0027] In some embodiments, in the thickness direction of the pole, the shortest vertical distance between the interface between the first metal layer and the second metal layer and the rear side surface of the pressing plate is L1, and L1 satisfies: 0≤L1≤1.5mm.

[0028] In some embodiments, the first metal layer is aluminum and the second metal layer is copper.

[0029] In some embodiments, the pressing plate and the first metal layer are made of the same material.

[0030] In some embodiments, in the thickness direction of the pole, the shortest vertical distance from the connection surface between the rear side of the pressing plate and the insulating member to the weld mark is L2, and L2 satisfies:

[0031] 0≤L2≤2.5mm.

[0032] In some embodiments, the insulating member is connected to at least a portion of the rear side of the pressing plate.

[0033] In some embodiments, the insulating member is at least partially connected to an outer peripheral side of the second metal layer.

[0034] In some embodiments, the insulating member comprises:

[0035] A plane portion, the plane portion is arranged between the pressing plate and the cover plate to separate the pressing plate and the cover plate;

[0036] A vertical portion extends into the mounting hole and extends toward the rear side of the mounting hole; and the vertical portion is arranged relative to the outer peripheral side of the second metal layer.

[0037] In some embodiments, a seal is further included, which is disposed between the cover plate and the pole and arranged on the rear side of the insulating member, and the seal is at least partially disposed in the mounting hole and connected to the second metal layer.

[0038] In some embodiments, a projection of the insulating member on the cover plate covers a projection of the sealing member on the cover plate.

[0039] In some embodiments, the thickness H1 of the first metal layer, the thickness H2 of the second metal layer, and the depth H3 of the weld mark satisfy:

[0040]

[0041] In some embodiments, the thermal deformation temperature of the insulating member is T, and T satisfies: 150° C. ≤ T ≤ 350° C., and the thickness H1 of the first metal layer, the thickness H2 of the second metal layer, and the depth H3 of the weld mark satisfy:

[0042]

[0043] Based on the above-mentioned cover plate assembly, the present application also provides a battery, which includes a pole ear and any of the above-mentioned cover plate assemblies, and the pole ear is electrically connected to the pole.

[0044] In some embodiments, the projections of the pole lug and the weld print in the thickness direction of the pole overlap, and the thickness H1 of the first metal layer, the thickness H2 of the second metal layer, and the depth H3 of the weld print satisfy:

[0045]

[0046] Compared with the prior art, the cover plate assembly and the battery in the embodiment of the present application have the following beneficial effects:

[0047] The cover plate assembly of the present application adopts a pole formed by a composite of a first metal layer and a second metal layer, and the melting point of the first metal layer is lower than the melting point 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 and greater than the thermal conductivity of the pressure plate. In this way, when the pressure plate is welded and fixed on the outer peripheral side of the first metal layer, the second metal layer can take away the heat generated by the welding more quickly, thereby reducing the heat transferred to the insulating part and avoiding overheating and softening of the insulating part. Moreover, the thickness H1 of the first metal layer and the thickness H2 of the second metal layer will affect the welding strength and the thermal conductivity of the pole. By controlling the relative ratio of the three parameters of the thickness H1 of the first metal layer, the thickness H2 of the second metal layer, and the depth H3 of the weld mark, the cover plate assembly can achieve a matching effect between the welding strength and the thermal conductivity, so that the cover plate assembly has both sufficient welding strength and the ability to achieve the expected thermal conductivity, avoiding the thickness H1 of the first metal layer being too small to affect the welding strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 is a schematic diagram of a cover plate assembly in an embodiment of the present application;

[0049] Figure 2 is a top view of the cover plate assembly in an embodiment of the present application;

[0050] Figure 3 yes Figure 2 Schematic diagram of the AA section;

[0051] Figure 4 yes Figure 3 Another example schematic diagram of the structure shown;

[0052] Figure 5 yes Figure 4 Another example schematic diagram of the structure shown;

[0053] Figure 6 yes Figure 5 Enlarged view of B.

[0054] In the figure, 100, cover plate assembly;

[0055] 1. Cover plate; 2. Pole; 20. First metal layer; 21. Second metal layer; 210. Recessed portion; 22. Interface; 3. Press plate; 4. Insulator; 40. Plane portion; 41. Vertical portion; 5. Welding mark; 6. Sealing member. DETAILED DESCRIPTION

[0056] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0057] In the description of the present invention, it should be understood that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element. The terms "installed", "connected" and "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 a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0058] In the description of the present invention, it should be understood that the terms "height", "up", "down", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like used in the present invention to indicate the orientation or position relationship are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention 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 cannot be understood as a limitation on the present invention.

[0059] In the description of the present invention, it should be understood that the terms "first" and "second" are used in the present invention for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0060] Example

[0061] like Figure 1-6As shown, the embodiment of the present application provides a cover plate assembly 100, which is suitable for a power battery. With the output interface of the power battery facing the front side, and the side opposite to the front side being the rear side, the cover plate assembly 100 includes a cover plate 1, a pole 2, a pressure plate 3 and an insulating member 4, wherein the cover plate 1 is provided with mounting holes arranged through the front and back along the thickness direction thereof, the pole 2 is penetrated through the mounting hole, so that part of the pole 2 passes through the mounting hole and extends to the front side of the mounting hole, the pressure plate 3 is provided on the front side of the cover plate 1 and sleeved on the pole 2, and the insulating member 4 is provided between the pressure plate 3 and the cover plate 1, so that the pressure plate 3 is separated from the cover plate 1.

[0062] refer to Figure 1-3 , the pole 2 is divided into a first metal layer 20 and a second metal layer 21 along its thickness direction, the first metal layer 20 is located in front of the second metal layer 21, and the melting point of the first metal layer 20 is lower than the melting point of the second metal layer 21, and the thermal conductivity (i.e. thermal conductivity) of the second metal layer 21 is higher than the thermal conductivity of the first metal layer 20. In addition, the pressing plate 3 is welded and fixed to the outer peripheral side of the first metal layer 20, so that a weld mark 5 is formed between the pressing plate 3 and the first metal layer 20. In addition, the thickness of the first metal layer 20 is H1, the thickness of the second metal layer 21 is H2, and the depth of the weld mark 5 is H3, and the above parameters satisfy:

[0063]

[0064] Exemplarily, the ratio of the thickness H1 of the first metal layer 20, the thickness H2 of the second metal layer 21, and the depth H3 of the weld mark 5 based on formula (1) can be one of 0.7, 0.8, 0.9, 1, 1.1, 1.5, 1.6, 1.7, 1.8, 2, 2.1, 2.5, 2.6, 2.7, 2.8, 3, 3.1, 3.5, 3.6, 3.7, 3.8, 4, 4.1, 4.5, 4.6, 4.7, 4.8, 5, 5.1, 5.5, 5.6, 5.7, 5.8, 6, 6.1, 6.5, 6.6, 6.8, 7, 7.1, 7.5, 7.6, 7.7, 7.8, 8.

[0065] It can be understood that the thickness H1 of the first metal layer 20 refers to the maximum thickness value of the first metal layer 20 in its thickness direction, and correspondingly, the thickness H2 of the second metal layer 21 refers to the maximum thickness value of the second metal layer 21 in its thickness direction.

[0066] It should be noted that the depth H3 of the weld mark 5 reflects the heat generated by the welding of the pole 2 and the pressure plate 3. The greater the depth H3 of the weld mark 5, the larger the welding area between the pole 2 and the pressure plate 3, and the more heat will be generated by the welding of the pole 2 and the pressure plate 3. Since the thermal conductivity of the second metal layer 21 is greater than the thermal conductivity of the first metal layer 20, the greater the proportion of the second metal layer 21 in the pole 2, the faster the heat dissipation efficiency of the pole 2. Of course, since the weld mark 5 is formed between the pressure plate 3 and the first metal layer 20, the proportion of the second metal layer 21 in the pole 2 is too large, which will also compress the volume of the first metal layer 20, affect the area of ​​the weld mark 5, and further affect the welding strength of the pole 2 and the pressure plate 3.

[0067] Therefore, by controlling the ratio of the thickness H1 of the first metal layer 20, the thickness H2 of the second metal layer 21, and the depth H3 of the weld mark 5, the cover plate assembly 100 can achieve a matching effect between the welding strength and the thermal conductivity. If the ratio of the thickness H1 of the first metal layer 20, the thickness H2 of the second metal layer 21, and the depth H3 of the weld mark 5 is greater than 8, the proportion of the first metal layer 20 in the pole 2 is too large, and the proportion of the second metal layer in the pole 2 is too small, which will cause the heat generated by the welding of the pressure plate 3 and the pole 2 to be unable to be taken away in time, and the insulating part 4 is easily softened by heat, resulting in insulation failure. If the ratio of the thickness H1 of the first metal layer 20, the thickness H2 of the second metal layer 21, and the depth H3 of the weld mark 5 is less than 0.7, the proportion of the first metal layer 20 in the pole 2 is too small, and the depth H3 of the weld mark 5 is insufficient, which will cause insufficient welding strength between the pressure plate 3 and the pole 2, and easily cause failure of the connection between the pressure plate 3 and the pole 2.

[0068] In order to verify that when the structural parameters of the cover plate assembly 100 provided in the present embodiment satisfy the above relationship, that is, when the thickness H1 of the first metal layer 20, the thickness H2 of the second metal layer 21, and the depth H3 of the weld mark 5 match, the cover plate assembly 100 of the present embodiment can have sufficient welding strength compared with other cover plate assemblies 100, 10 groups of tests were conducted, refer to the following Table 1:

[0069] In Table 1, Test Examples 1 to 10 are tests based on the structure of the cover plate assembly 100 of the present embodiment, that is, the width W1 of the pressing plate 3, the thickness t1 of the pressing plate 3, the width W2 of the flange portion 21, and the thickness t2 of the flange portion 21 of the cover plate assembly 100 of Test Examples 1 to 10 satisfy the above matching relationship. Comparative Examples 1 and 2 are other cover plate assembly structures, that is, the width W1 of the pressing plate 3, the thickness t1 of the pressing plate 3, the width W2 of the flange portion 21, and the thickness t2 of the flange portion 21 of Comparative Examples 1 and 2 do not satisfy the above matching relationship.

[0070] The tensile force test method is as follows: 20 batteries are taken for each experiment, a tensile block is installed on the surface of the pole 2, and the tensile block is connected to a tensile machine (model: universal testing machine DNS-2). After the pressure ring 3 is fixed, the tensile machine pulls the pole 2 through the tensile block, and the tensile machine sensor (sensor model: CLY30) is turned on to collect the tensile force value of the tensile block until the pole 2 falls off. The maximum value in the tensile force curve is read, and the maximum value in the tensile force curve is above 1200N to be qualified.

[0071] The thermal conductivity test method is as follows: 20 batteries are taken for each experiment, and a current source (RDTS-02) is placed on the upper and lower surfaces of the pole, and a thermometer (LR8450) is placed on the lower surface of pole 2. A current of 500A is passed, and temperature data is collected through the thermometer after 1 minute. If the temperature exceeds 60 degrees Celsius, it is unqualified.

[0072] Table 1

[0073]

[0074]

[0075] As can be seen from Table 1, when the thickness H1 of the first metal layer 20, the thickness H2 of the second metal layer 21, and the depth H3 of the weld mark 5 satisfy the above matching relationship, the pole 2 of the cover plate assembly 100 can withstand a tensile force of more than 1200N, and ensure no air leakage, and the thermal conductivity meets the requirements. However, when the thickness H1 of the first metal layer 20, the thickness H2 of the second metal layer 21, and the depth H3 of the weld mark 5 do not satisfy the above matching relationship, this type of cover plate assembly will have the problem that the pole 2 can not withstand enough tensile force, or the air tightness is insufficient, or the thermal conductivity is insufficient.

[0076] When the pressure plate 3 is welded to the pole 2, the welding originates from the front side of the pole 2 near the intersection of the pressure plate 3 and the first metal layer 20, so that the pressure plate 3 and the first metal layer 20 are welded and fixed. Since the melting point of the second metal layer 21 is higher than the melting point of the first metal layer 20, the second metal layer 21 will not melt when the pressure plate 3 and the first metal layer 20 are welded and fixed, thereby ensuring the stability of the overall structure of the pole 2 and the stable connection between the pole 2 and the battery cell.

[0077] It is understandable that the first metal layer 20 and the second metal layer 21 can be selected according to the specification parameters of the pole 2. For example, considering the applicability of laser welding, the first metal layer 20 can be metal aluminum and the second metal layer 21 can be metal copper. In addition, the pressing plate 3 can be made of the same material as the first metal layer 20 to facilitate welding operation and temperature control during welding. For example, when the first odd-numbered layer is metal aluminum, the pressing plate 3 can also be made of metal aluminum.

[0078] The heat generated by welding will be transferred outward through the pressing plate 3 and the first metal layer 20. In the process of heat transfer, since the thermal conductivity of the second metal layer 21 is greater than that of the first metal layer 20 and greater than that of the pressing plate 3, and the second metal layer 21, as a structural layer of metal material, must have a much greater thermal conductivity than that of the insulating member 4, the heat generated by welding will be transferred more to the second metal layer 21, so that the second metal layer 21 can quickly take away the heat generated by welding, avoiding excessive heat transfer to the insulating member 4, causing the insulating member 4 to overheat and soften, thereby affecting the insulation effect.

[0079] It should be noted that the shape design of the insulating member 4 is diverse, and it can be an integrated structure or a split structure. The insulating member 4 is placed in whole or in part between the cover plate 1 and the pressing plate 3, so that the cover plate 1 and the pressing plate 3 can be separated. According to the specification parameters of the pressing plate 3 and the insulating member 4, the width of the insulating member 4 itself is not necessarily equal to the width of the pressing plate 3 itself, and the width of the insulating member 4 can be smaller than the width of the pressing plate 3, so that the insulating member 4 is connected to the rear side of the pressing plate 3, or, as Figure 3 As shown, as an example of this embodiment, the width of the insulating member 4 may be greater than or equal to the width of the pressing plate 3 , so that the insulating member 4 is integrally connected to the rear side of the pressing plate 3 .

[0080] For power batteries, the thickness and diameter of the pole 2 will have corresponding standard sizes. Therefore, the thickness H1 of the first metal layer 20 and the thickness H2 of the second metal layer 21 affect each other. If the thickness H1 of the first metal layer 20 is large, although the welding strength between the pole 2 and the pressure plate 3 will be guaranteed, the thickness H2 of the second metal layer 21 will be small accordingly, which will affect the rapid evacuation of heat; correspondingly, if the thickness H2 of the second metal layer 21 is large, although the thermal conductivity of the pole 2 will be guaranteed, the thickness H1 of the first metal layer 20 will be small accordingly, resulting in a corresponding reduction in the depth of the weld mark 5, which will affect the welding strength between the pole 2 and the pressure plate 3. Therefore, the thickness H1 of the first metal layer 20, the thickness H2 of the second metal layer 21, and the depth H3 of the weld mark 5 should meet a certain range of values ​​and meet the corresponding ratio relationship.

[0081] For example, the thickness H1 of the first metal layer 20 may satisfy: 2≤H1≤4mm, so that the first metal layer 20 has sufficient thickness, thereby ensuring that the weld mark 5 generated when the pressing plate 3 is welded to the first metal layer 20 has sufficient depth. Exemplarily, the thickness H1 of the first metal layer 20 may be one of 2mm, 2.5mm, 3mm, 3.5mm, and 4mm.

[0082] Alternatively, the thickness H2 of the second metal layer 21 may satisfy: 1≤H2≤2mm, so that the second metal layer 21 has sufficient thickness to ensure that the pole 2 can dissipate the heat generated by welding in time. Exemplarily, the thickness H2 of the second metal layer 21 may be one of 1mm, 1.5mm, and 2mm.

[0083] Alternatively, the depth H3 of the weld mark 5 may satisfy: 0.4≤H3≤2mm, so as to ensure that there is a sufficient welding area between the pressure plate 3 and the pole 2, so that the pressure plate 3 and the pole 2 are firmly connected. Exemplarily, the depth H3 of the weld mark 5 may be 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2mm.

[0084] When the heat generated by welding is transferred to the second metal layer 21, the second metal layer 21 should have a certain heat dissipation effect, so that the second metal layer 21 can maintain a certain temperature difference with the first metal layer 20 and the pressing plate 3 to ensure the transfer efficiency of heat conduction.

[0085] refer to Figure 3 As an example of this embodiment, the cover plate assembly 100 may further include a seal 6, which is disposed between the cover plate 1 and the pole 2 and arranged on the rear side of the insulating member 4, and the seal 6 is at least partially disposed in the mounting hole and in contact with the second metal layer 21, so that the outer peripheral side of the second metal layer 21 can be sealed by the seal 6 to meet the sealing requirements between the pole 2 and the cover plate 1. The size of the seal 6 can be configured according to the size of the insulating member 4, so that the projection of the insulating member 4 on the cover plate 1 can cover the projection of the seal 6 on the cover plate 1, so that the insulating member 4 and the seal 6 cooperate with each other, so that the cover plate assembly 100 can obtain better sealing and insulation effects.

[0086] Generally speaking, the area in the same welding direction as the weld mark 5 is more heated than other areas. The position where the seal 6 contacts the pole 2 is likely to cause the seal 6 to melt, resulting in seal failure. To this end, the relationship between the thickness H1 of the first metal layer 20, the thickness H2 of the second metal layer 21, and the depth H3 of the weld mark 5 can be adjusted to meet the following conditions:

[0087]

[0088] This is to reduce the impact of the heat generated by welding on the sealing member 6.

[0089] Exemplarily, the ratio of the thickness H1 of the first metal layer 20, the thickness H2 of the second metal layer 21, and the depth H3 of the weld mark 5 based on formula (2) can be one of 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 2, 2.1, 2.5, 2.6, 2.7, 2.8, 3, 3.1, 3.5, 3.6, 3.7, 3.8, 4, 4.1, 4.5, 4.6, 4.7, 4.8, 5, 5.1, 5.5, 5.6, 5.7, 5.8, 6, 6.1, 6.5, 6.6, 6.7, 6.8, 7, 7.1, 7.5, 7.6, 7.7, 7.8, 8.

[0090] refer to Figure 4 As another example of this embodiment, the rear side of the second metal layer 21 is recessed toward the front side along the thickness direction thereof to form a recessed portion 210, so that the second metal layer 21 forms an outer contour structure similar to a "J" shape. The hollow structure formed by the recessed portion 210 can effectively expand the heat dissipation area of ​​the second metal layer 21 intersecting with the outside, so as to dissipate the heat of the second metal layer 21 in a timely manner.

[0091] It can be understood that the thickness H2 of the second metal layer 21 affects the thermal conductivity of the second metal layer 21. The larger the thickness H2 of the second metal layer 21, the more heat the second metal layer 21 can absorb, and the more heat the second metal layer 21 needs to dissipate. Correspondingly, the depth of the recess 210 affects the heat dissipation performance of the second metal layer 21. The greater the depth of the recess 210, the larger the heat dissipation area expanded by the second metal layer 21, and its heat dissipation performance will be improved accordingly. Of course, the depth of the recess 210 affects the size of the second metal layer 21 itself, that is, it affects the structural strength of the second metal layer 21. Therefore, the thickness H2 of the second metal layer 21 and the depth of the recess 210 should be considered to be maintained within an appropriate range. For example, the depth of the recess 210 is H4, and the depth H4 of the recess 210 and the thickness H2 of the second metal layer 21 satisfy:

[0092]

[0093] Alternatively, the depth H4 of the recess 210 satisfies: 1≤H4≤4mm, to ensure that the thickness H2 of the second metal layer 21 matches the depth H4 of the recess 210, so that the heat absorbed by the second metal layer 21 can be dissipated in time by the recess 210, avoiding the accumulation of heat in the second metal layer 21 close to the first metal layer 20 due to the recess 210 being too small, causing the diaphragm between the first metal layer 20 and the second metal layer 21 to shrink due to the heat. Exemplarily, the depth H4 of the recess 210 may be one of the sizes of 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, 3mm, 3.1mm, 3.2mm, 3.3mm, 3.4mm, 3.5mm, 3.6mm, 3.7mm, 3.8mm, 3.9mm, and 4mm.

[0094] Exemplarily, the ratio of the depth H4 of the recess 210 to the thickness H2 of the second metal layer 21 based on formula (3) can be one of 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.8, 2, 2.1, 2.5, 2.6, 2.8, 3, 3.1, 3.5, 3.6, 3.8, or 4.

[0095] Since the pressing plate 3 is arranged on the front side of the cover plate 1, the insulating member 4 arranged between the pressing plate 3 and the cover plate 1 is generally attached to the rear side of the pressing plate 3, so that there is direct contact between the insulating member 4 and the pressing plate 3. If the second metal layer 21 is far away from the pressing plate 3 or has no contact with the pressing plate 3, the heat absorbed by the pressing plate 3 will be transferred to the insulating member 4, which may easily cause the insulating member 4 to overheat. Therefore, the relative position of the second metal layer 21 and the pressing plate 3 needs to be considered so that the heat of the pressing plate 3 can be evacuated to the second metal layer 21 in time.

[0096] refer to Figure 4 As an example of this embodiment, the interface 22 between the first metal layer 20 and the second metal layer 21 is flush with the rear side of the pressing plate 3, and the thickness H1 of the first metal layer 20, the thickness H2 of the second metal layer 21, and the depth H3 of the weld mark 5 satisfy:

[0097]

[0098] It can be understood that the interface 22 between the first metal layer 20 and the second metal layer 21 is flush with the rear side of the pressure plate 3, so that the second metal layer 21 can be close to the pressure plate 3. In this way, when heat energy diffuses from the weld mark 5 to the rear side, more heat energy will diffuse to the second metal layer 21, so that the heat of the pressure plate 3 can be evacuated to the second metal layer 21 in time.

[0099] Exemplarily, the ratio of the thickness H1 of the first metal layer 20, the thickness H2 of the second metal layer 21, and the depth H3 of the weld mark 5 based on formula (4) can be one of 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 2, 2.1, 2.5, 2.6, 2.7, 2.8, 3, 3.1, 3.5, 3.6, 3.7, 3.8, 4, 4.1, 4.2, and 4.3.

[0100] Alternatively, refer to Figure 5 As another example of this embodiment, the interface 22 between the first metal layer 20 and the second metal layer 21 is located at the front side of the rear side of the pressing plate 3, so that the second metal layer 21 can form direct contact with the pressing plate 3, and the thickness H1 of the first metal layer 20, the thickness H2 of the second metal layer 21, and the depth H3 of the weld mark 5 satisfy:

[0101]

[0102] It can be understood that the interface 22 between the first metal layer 20 and the second metal layer 21 is located on the front side of the rear side of the pressure plate 3, so that the second metal layer 21 is in direct contact with the pressure plate 3. In this way, when heat energy diffuses from the weld mark 5 to the rear side, more heat energy diffuses to the second metal layer 21, so that the heat of the pressure plate 3 can be evacuated to the second metal layer 21 in time.

[0103] Exemplarily, the ratio of the thickness H1 of the first metal layer 20, the thickness H2 of the second metal layer 21, and the depth H3 of the weld mark 5 based on formula (5) can be one of 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 2, 2.1, 2.5, 2.6, 2.7, 2.8, 3, 3.1, 3.5, 3.6, 3.8, 4, 4.1, 4.5, 4.6, 4.8, 5, 5.1, 5.5, 5.6, 5.8, 6, 6.1, 6.5, 6.6, 6.8, 7, 7.1, 7.5, 7.6, 7.8, 8.

[0104] The thickness H1 of the first metal layer 20 and the thickness H2 of the second metal layer 21 determine the junction position of the first metal layer 20 and the second metal layer 21. In the thickness direction of the pole 2, the shortest vertical distance between the interface 22 (i.e., the junction position) of the first metal layer 20 and the second metal layer 21 and the rear side of the pressing plate 3 can reflect the area of ​​direct contact between the pressing plate 3 and the second metal layer 21, and the area of ​​direct contact between the pressing plate 3 and the first metal layer 20. If the shortest vertical distance between the interface 22 of the first metal layer 20 and the second metal layer 21 and the rear side of the pressing plate 3 is too small, the second metal layer 21 may not be able to dissipate the heat generated by welding in time; if the shortest vertical distance between the interface 22 of the first metal layer 20 and the second metal layer 21 and the rear side of the pressing plate 3 is too large, the contact area between the first metal layer 20 and the pressing plate 3 may be insufficient, affecting the strength of the welding. Therefore, in the thickness direction of the pole 2, the shortest vertical distance between the interface 22 of the first metal layer 20 and the second metal layer 21 and the rear side of the pressing plate 3 is L1, and L1 can be considered to satisfy: 0≤L1≤1.5mm. Exemplarily, the shortest vertical distance between the interface 22 of the first metal layer 20 and the second metal layer 21 and the rear side of the pressing plate 3 is L1, which can be 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm.

[0105] Of course, in addition to adjusting the relative position relationship between the second metal layer 21 and the pressing plate 3, the relative position relationship between the insulating member 4 and the second metal layer 21 can also be adjusted so that the heat absorbed by the insulating member 4 itself can be promptly dissipated by the second metal layer 21. For example, the insulating member 4 is at least partially connected to the outer peripheral side of the second metal layer 21.

[0106] refer to Figure 4 As an example of this embodiment, the insulating member 4 may include a planar portion 40 and a vertical portion 41, wherein the planar portion 40 is arranged between the pressure plate 3 and the cover plate 1 to separate the pressure plate 3 and the cover plate 1; the vertical portion 41 extends into the mounting hole and extends toward the rear side of the mounting hole; and the vertical portion 41 is arranged relative to the outer peripheral side of the second metal layer 21 to connect with the second metal layer 21.

[0107] Of course, the insulating part 4 can also be configured with structures of other shapes and contours according to the specifications of the cover assembly 100 itself, so that part of the structure of the insulating part 4 itself can be connected to the outer peripheral side of the second metal layer 21, so that the insulating part 4 and the second metal layer 21 are directly connected, allowing the insulating part 4 to generate heat conduction with the second metal layer 21.

[0108] It is understandable that the temperature resistance of the insulating member 4 will also affect the performance of the pole 2. The better the temperature resistance of the insulating member 4, the less likely it is to soften when the pole 2 and the pressure plate 3 are welded. Correspondingly, the thickness of the second metal layer 21 of the pole 2 can be reduced accordingly. As an example of this embodiment, the thermal deformation temperature of the insulating member 4 is T, and T satisfies: 150℃≤T≤350℃. In this case, the thickness H1 of the first metal layer 20, the thickness H2 of the second metal layer 21, and the depth H3 of the weld mark 5 can satisfy:

[0109]

[0110] It can be understood that the heat deformation temperature T of the insulating member 4 reflects the heat resistance of the insulating member 4. The better the heat resistance of the insulating member, the greater the welding heat allowed to be generated between the pressing plate 3 and the pole 2, and the greater the depth H3 of the weld mark 5, so that the connection strength between the pressing plate 3 and the pole 2 is better. Exemplarily, the heat deformation temperature T of the insulating member 4 can be one of 150°C, 175°C, 200°C, 250°C, 275°C, 300°C, 325°C, and 350°C.

[0111] Exemplarily, the ratio of the thickness H1 of the first metal layer 20, the thickness H2 of the second metal layer 21, and the depth H3 of the weld mark 5 based on formula (6) can be one of 1.5, 1.6, 1.8, 2, 2.1, 2.5, 2.6, 2.8, 3, 3.1, 3.5, 3.6, 3.8, 4, 4.1, 4.5, 4.6, 4.8, 5, 5.1, 5.5, 5.6, 5.8, 6, 6.1, 6.5, 6.6, 6.8, 7, 7.1, 7.5, 7.6, 7.8, or 8.

[0112] In addition to the fact that the heat dissipation performance of the pole 2 will affect the heat borne by the insulating member 4, the weld mark 5 is the area directly affected by the welding process, which is generally the area with the highest heat. If the weld mark 5 is too close to the insulating member 4, the heat borne by the insulating member 4 will also increase, causing the insulating member 4 to soften. Figure 6As an example of this embodiment, in the thickness direction of the pole 2, the shortest vertical distance from the connection surface between the rear side of the pressing plate 3 and the insulating member 4 to the weld mark 5 is L2, and L2 satisfies: 0≤L2≤2.5mm. Exemplarily, the shortest vertical distance L2 from the connection surface between the rear side of the pressing plate 3 and the insulating member 4 to the weld mark 5 can be 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm.

[0113] Based on the above-mentioned cover plate assembly 100, this embodiment also provides a battery (not shown in the figure), which includes a pole ear (not shown in the figure) and any of the above-mentioned cover plate assemblies 100, the pole ear is arranged on the rear side of the cover plate 1, close to the second metal layer 21, and is electrically connected to the pole 2.

[0114] Considering that the location of the tab may be behind the weld mark 5, so that the projection of the tab and the weld mark 5 in the thickness direction of the pole 2 overlaps, in this case, the heat generated by welding may affect the tab. In this regard, the thickness H1 of the first metal layer 20, the thickness H2 of the second metal layer 21, and the depth H3 of the weld mark 5 may satisfy:

[0115]

[0116] The thickness of the second metal layer 21 is increased so that the second metal layer 21 can dissipate heat quickly.

[0117] Exemplarily, the ratio of the thickness H1 of the first metal layer 20, the thickness H2 of the second metal layer 21, and the depth H3 of the weld mark 5 based on formula (7) can be one of 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.8, 2, 2.1, 2.5, 2.6, 2.8, 3, 3.1, 3.5, 3.6, 3.8, 4, 4.1, 4.5, 4.6, 4.8, 5, 5.1, 5.5, 5.6, 5.8, 6, 6.1, 6.5, 6.6, 6.8, 7, 7.1, 7.5, 7.6, 7.8, or 8.

[0118] In summary, the embodiment of the present application provides a cover plate assembly 100 and a battery, which adopts a pole 2 formed by a composite of a first metal layer 20 and a second metal layer 21, and makes the melting point of the first metal layer 20 lower than the melting point of the second metal layer 21, and the thermal conductivity of the second metal layer 21 is higher than the thermal conductivity of the first metal layer 20, and higher than the thermal conductivity of the pressure plate 3. In this way, when the pressure plate 3 is welded and fixed on the outer peripheral side of the first metal layer 20, the second metal layer 21 can take away the heat generated by the welding more quickly, thereby reducing the heat transferred to the insulation. The heat of the edge member 4 can prevent the insulating member 4 from being overheated and softened. In addition, the thickness H1 of the first metal layer 20 and the thickness H2 of the second metal layer 21 will affect the welding strength and the thermal conductivity of the pole 2. By controlling the relative ratio of the three parameters of the thickness H1 of the first metal layer 20, the thickness H2 of the second metal layer 21, and the depth H3 of the weld mark 5, the cover assembly 100 can achieve a matching effect between the welding strength and the thermal conductivity, so that the cover assembly 100 has both sufficient welding strength and the ability to achieve the expected thermal conductivity.

[0119] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A cover plate assembly, comprising: A cover plate, wherein the cover plate is provided with mounting holes that penetrate the cover plate from front to back along the thickness direction thereof; A pole, the pole being passed through the mounting hole; A pressing plate, the pressing plate is sleeved on the pole; An insulating member, wherein the insulating member is disposed between the pressing plate and the cover plate to separate the pressing plate from the cover plate; wherein: The pole is divided into a first metal layer and a second metal layer along the thickness direction thereof, the first metal layer is located in front of the second metal layer, and the melting point of the first metal layer is lower than the melting point of the second metal layer, and the thermal conductivity of the second metal layer is higher than the thermal conductivity of the first metal layer and higher than the thermal conductivity of the pressing plate; and, The pressing plate is welded and fixed to the outer peripheral side of the first metal layer, so that a welding mark is formed between the pressing plate and the first metal layer; and The thickness of the first metal layer is H1, the thickness of the second metal layer is H2, the depth of the weld mark is H3, and the above parameters satisfy:

2. The cover plate assembly according to claim 1, characterized in that: The thickness H1 of the first metal layer satisfies: 2≤H1≤4 mm.

3. The cover plate assembly according to claim 1, characterized in that: The thickness H2 of the second metal layer satisfies: 1≤H2≤2 mm.

4. The cover plate assembly according to claim 1, characterized in that: The depth H3 of the weld mark satisfies: 0.4≤H3≤2mm.

5. The cover plate assembly according to claim 1, characterized in that: The rear side of the second metal layer is recessed toward the front side along the thickness direction thereof to form a recessed portion.

6. The cover plate assembly according to claim 5, characterized in that: The depth of the recessed portion is H4, and the depth H4 of the recessed portion and the thickness H2 of the second metal layer satisfy:

7. The cover plate assembly according to claim 5, characterized in that: The depth H4 of the recessed portion satisfies: 1≤H4≤4mm.

8. The cover plate assembly according to claim 1, characterized in that: The interface between the first metal layer and the second metal layer is flush with the rear side of the pressing plate, and the thickness H1 of the first metal layer, the thickness H2 of the second metal layer, and the depth H3 of the weld mark satisfy:

9. The cover plate assembly according to claim 1, characterized in that: The interface between the first metal layer and the second metal layer is located at the front side of the rear side of the pressing plate, and the thickness H1 of the first metal layer, the thickness H2 of the second metal layer, and the depth H3 of the weld mark satisfy:

10. The cover plate assembly according to claim 9, characterized in that: In the thickness direction of the pole, the shortest vertical distance between the interface between the first metal layer and the second metal layer and the rear side surface of the pressing plate is L1, and L1 satisfies: 0≤L1≤1.5mm.

11. The cover plate assembly according to claim 1, characterized in that: The first metal layer is aluminum, and the second metal layer is copper.

12. The cover plate assembly according to claim 1, characterized in that: The pressing plate and the first metal layer are made of the same material.

13. The cover plate assembly according to claim 1, characterized in that: The insulating member is connected to at least a portion of the rear side surface of the pressing plate.

14. The cover plate assembly according to claim 1, characterized in that: In the thickness direction of the pole, the shortest vertical distance between the connection surface between the rear side of the pressing plate and the insulating member and the weld mark is L2, and L2 satisfies: 0≤L2≤2.5mm.

15. The cover plate assembly according to claim 14, characterized in that: The insulating member is at least partially connected to the outer peripheral side of the second metal layer.

16. The cover plate assembly according to claim 15, characterized in that: The insulating member comprises: A plane portion, the plane portion is arranged between the pressing plate and the cover plate to separate the pressing plate and the cover plate; A vertical portion extends into the mounting hole and extends toward the rear side of the mounting hole; and the vertical portion is arranged relative to the outer peripheral side of the second metal layer.

17. The cover plate assembly according to claim 1, characterized in that: The device further comprises a sealing member, which is disposed between the cover plate and the pole and arranged on the rear side of the insulating member, and at least partially disposed in the mounting hole and connected to the second metal layer.

18. The cover plate assembly according to claim 17, characterized in that: The projection of the insulating member on the cover plate covers the projection of the sealing member on the cover plate.

19. The cover plate assembly according to claim 17, characterized in that: The thickness H1 of the first metal layer, the thickness H2 of the second metal layer, and the depth H3 of the weld mark satisfy:

20. The cover plate assembly according to claim 1, characterized in that The thermal deformation temperature of the insulating member is T, and T satisfies: 150° C. ≤ T ≤ 350° C., and the thickness H1 of the first metal layer, the thickness H2 of the second metal layer, and the depth H3 of the weld mark satisfy:

21. A battery, characterized in that: It comprises a pole ear and a cover plate assembly as claimed in any one of claims 1 to 19, wherein the pole ear is arranged on the rear side of the cover plate, close to the second metal layer, and is electrically connected to the pole.

22. The battery according to claim 21, characterized in that The projections of the pole ear and the weld mark in the thickness direction of the pole overlap, and the thickness H1 of the first metal layer, the thickness H2 of the second metal layer, and the depth H3 of the weld mark satisfy:

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