A cover plate assembly and a battery

Abstract

The present invention discloses a cover plate assembly and a battery, relating to the technical field of batteries. It includes a pole column, and the pole column is divided into a first metal layer and a second metal layer along its thickness direction. The first metal layer is located on the front side of the second metal layer, and the melting point of the first metal layer is less than that of the second metal layer. The heat conduction rate of the second metal layer is greater than that of the first metal layer and greater than the heat conduction rate of the pressing plate, so that the second metal layer can quickly take away the heat generated by welding, avoiding overheating and softening of the insulating part. Moreover, the pressing plate is welded and fixed to the outer peripheral side of the first metal layer, 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, and the depth of the welding mark is H3, and the above parameters satisfy a preset relationship, so that this cover plate assembly can make the welding strength and the heat conduction effect reach a matching effect, making this cover plate assembly have both sufficient welding strength and the ability to achieve the expected heat conduction effect.

Description

Technical Field

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

[0002] A power battery is a battery that provides a power source for a tool. Generally, it includes a metal housing, a battery cell disposed within the metal housing, and a cover plate assembly fixed to the top of the metal housing. A pole structure is provided within the cover plate assembly, which plays a role in transmitting the electrical energy of the power battery. Therefore, the stability of the pole structure itself affects the performance of the power battery.

[0003] Currently, existing cover plate assemblies generally include structures such as a cover plate, a pressing plate, a pole, and an insulating member. Among them, the pole passes through the cover plate, and the pressing plate and the insulating member are sleeved on the pole. The pressing plate is connected and fixed to the pole by welding, so that the pole can neither undergo horizontal torsion nor axial movement. The insulating member is arranged between the pressing plate and the cover plate to isolate the electrical conduction between the pressing plate and the cover plate.

[0004] However, when the pole and the pressing plate are butt-welded, due to the high heat generated by the welding, it is extremely easy to cause the softening of the insulating member, resulting in the problem of insulation failure. Summary of the Invention

[0005] The purpose of the present invention is to provide a cover plate assembly and a battery, which can timely remove the heat generated by welding through improving the structural arrangement of the pole, and avoid the problem of insulation failure caused by the softening of the insulating member.

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

[0007] A cover plate assembly, comprising:

[0008] A cover plate, which is provided with an installation hole penetrating through in the front-back direction along its thickness direction;

[0009] A pole, which passes through the installation hole;

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

[0011] An insulating member, which is arranged 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 its thickness direction. The first metal layer is located on the front side of the second metal layer, and the melting point of the first metal layer is less than that of the second metal layer. The heat conduction rate of the second metal layer is greater than that of the first metal layer and greater than the heat conduction rate of the pressing plate; and,

[0013] The pressing plate is fixedly welded 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 H 1 , and the thickness of the second metal layer is H 2 , and the depth of the welding mark is H 3 , and the above parameters satisfy:

[0015]

[0016] In some embodiments, the thickness H of the first metal layer 1 satisfies: 2 ≤ H 1 ≤ 4 mm.

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

[0018] In some embodiments, the depth H of the welding mark 3 satisfies: 0.4 ≤ H 3 ≤ 2 mm.

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

[0020] In some embodiments, the depth of the recessed portion is H 4 , and the depth H of the recessed portion 4 and the thickness H of the second metal layer 2 satisfy:

[0021]

[0022] In some embodiments, the depth H of the recessed portion 4 satisfies: 1 ≤ H 4 ≤ 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 H of the first metal layer 1 , the thickness H of the second metal layer 2 , the depth H of the welding mark 3 satisfy:

[0024]

[0025] In some embodiments, the interface between the first metal layer and the second metal layer is located on the front side of the rear side of the pressing plate, and the thickness H of the first metal layer1 The thickness H of the second metal layer 2 The depth H of the welding mark 3 Satisfy:

[0026]

[0027] In some embodiments, in the thickness direction of the terminal post, the shortest vertical distance between the interface of the first metal layer and the second metal layer and the rear side surface of the pressing plate is L 1 and L 1 Satisfy: 0 ≤ L 1 ≤ 1.5 mm

[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 terminal post, the shortest vertical distance from the connection surface between the rear side of the pressing plate and the insulating member to the welding mark is L 2 and L 2 Satisfy:

[0031] 0 ≤ L 2 ≤ 2.5 mm

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

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

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

[0035] A planar portion disposed between the pressing plate and the cover plate to separate the pressing plate and the cover plate

[0036] A vertical portion extending into the mounting hole and extending toward the rear side of the mounting hole; and the vertical portion is disposed opposite to the outer peripheral side of the second metal layer

[0037] In some embodiments, a sealing member is further included, and the sealing member is disposed between the cover plate and the terminal post, arranged at the rear side of the insulating member, and at least part of the sealing member is disposed in the mounting hole and is in contact with the second metal layer

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

[0039] In some embodiments, the thickness H of the first metal layer 1 , the thickness H of the second metal layer 2 , the depth H of the welding mark 3 satisfy:

[0040]

[0041] In some embodiments, the heat distortion temperature of the insulating part is T, and T satisfies: 150°C ≤ T ≤ 350°C, and the thickness H of the first metal layer 1 , the thickness H of the second metal layer 2 , the depth H of the welding mark 3 satisfy:

[0042]

[0043] Based on the above cover plate assembly, the present application further provides a battery, which includes a tab and any one of the foregoing cover plate assemblies, and the tab is electrically connected to the terminal post.

[0044] In some embodiments, the projection of the tab and the welding mark in the thickness direction of the terminal post partially overlap, and the thickness H of the first metal layer 1 , the thickness H of the second metal layer 2 , the depth H of the welding mark 3 satisfy:

[0045]

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

[0047] The cover plate assembly of the present application adopts a terminal post composed of a composite of a first metal layer and a second metal layer, and makes the melting point of the first metal layer less than that of the second metal layer, and the heat conduction rate of the second metal layer greater than that of the first metal layer and greater than that of the pressing plate. In this way, when the pressing 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 welding more quickly, thereby reducing the heat transferred to the insulating part and avoiding overheating and softening of the insulating part. Moreover, the thickness H of the first metal layer 1 , the thickness H of the second metal layer 2 will affect the welding strength and the heat conduction effect of the terminal post. By controlling the thickness H of the first metal layer 1 , the thickness H of the second metal layer 2 , the depth H of the welding mark 3The relative ratios of the three parameters enable the cover plate assembly to achieve a matching effect between the welding strength and the heat conduction effect, so that the cover plate assembly not only has sufficient welding strength but also can achieve the expected heat conduction effect, avoiding the thickness H of the first metal layer 1 from being too small and affecting the welding strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 is a schematic diagram of the 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 is Figure 2 a schematic diagram of the A-A cross-section in

[0051] Figure 4 is Figure 3 another schematic diagram of the structure shown in

[0052] Figure 5 is Figure 4 another schematic diagram of the structure shown in

[0053] Figure 6 is Figure 5 an enlarged view of B in

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

[0055] 1 is the cover plate; 2 is the pole column; 20 is the first metal layer; 21 is the second metal layer; 210 is the recess; 22 is the interface; 3 is the pressure plate; 4 is the insulating part; 40 is the flat part; 41 is the vertical part; 5 is the welding mark; 6 is the seal. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0056] The following will further describe in detail the specific embodiments of the present invention in conjunction with the drawings and embodiments. The following embodiments 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 "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 "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element. The terms "mounted", "connected", and "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 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 specific circumstances.

[0058] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "height", "upper", "lower", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. in the present invention is based on the orientation or positional relationship shown in the drawings. It is 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 should not be construed as a limitation to the present invention.

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

[0060] Embodiment

[0061] As Figures 1-6 As shown, an embodiment of the present application provides a cover assembly 100 applicable to a power battery. Taking the output interface orientation of the power battery as the front side and the side opposite to the front side as the rear side, the cover assembly 100 includes a cover 1, a pole column 2, a pressing plate 3, and an insulating member 4. Among them, the cover 1 is provided with a mounting hole penetrating through in the front-rear direction along its thickness direction, the pole column 2 is inserted into the mounting hole, so that a part of the pole column 2 passes through the mounting hole and extends to the front side of the mounting hole, the pressing plate 3 is disposed on the front side of the cover 1 and sleeved on the pole column 2, and the insulating member 4 is disposed between the pressing plate 3 and the cover 1 to separate the pressing plate 3 from the cover 1.

[0062] Reference Figures 1-3The 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 that of the second metal layer 21. The thermal conductivity (i.e., thermal conductivity) of the second metal layer 21 is higher than that of the first metal layer 20. In addition, the pressing plate 3 is welded 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 H 1 , the thickness of the second metal layer 21 is H 2 , the depth of weld mark 5 is H 3 , the above parameters satisfy:

[0063]

[0064] For example, the thickness H of the first metal layer 20 is 1 , the thickness H of the second metal layer 21 2 , the depth H of weld mark 5 3 The ratio of the three 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 H of the first metal layer 20 is 1 It refers to the maximum thickness value of the first metal layer 20 in its thickness direction. Correspondingly, the thickness H of the second metal layer 21 2 It refers to the maximum thickness of the second metal layer 21 in its thickness direction.

[0066] It should be noted that the depth H of the weld mark 5 3 It reflects the heat generated by welding the pole 2 and the pressure plate 3. The depth H of the weld mark 5 3 The larger the value, 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 larger 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, if the proportion of the second metal layer 21 in the pole 2 is too large, the volume of the first metal layer 20 will be compressed, affecting the area of ​​the weld mark 5, and further affecting the welding strength between the pole 2 and the pressure plate 3.

[0067] Therefore, by controlling the thickness H of the first metal layer 20 1 、the thickness H of the second metal layer 21 2 、and the depth H of the welding mark 5 3 The ratio of the three can enable the welding strength and heat conduction effect of the cover plate assembly 100 to reach a matching effect. If the thickness H of the first metal layer 20 1 、the thickness H of the second metal layer 21 2 、and the depth H of the welding mark 5 3 The ratio of the three is greater than 8, the proportion of the first metal layer 20 in the terminal post 2 is too large, and the proportion of the second metal layer in the terminal post 2 is too small, which will cause the heat generated by the welding of the pressure plate 3 and the terminal post 2 to not be taken away in time, and the insulating part 4 is prone to heat softening and causing insulation failure. If the thickness H of the first metal layer 20 1 、the thickness H of the second metal layer 21 2 、and the depth H of the welding mark 5 3 The ratio of the three is less than 0.7, the proportion of the first metal layer 20 in the terminal post 2 is too small, and the depth H of the welding mark 5 3 is insufficient, which will result in insufficient welding strength between the pressure plate 3 and the terminal post 2, and is likely to cause the connection between the pressure plate 3 and the terminal post 2 to fail.

[0068] In order to verify that when the structural parameters of the cover plate assembly 100 provided in this embodiment satisfy the above relational expression, that is, the thickness H of the first metal layer 20 1 、the thickness H of the second metal layer 21 2 、and the depth H of the welding mark 5 3 When they are matched, compared with other cover plate assemblies 100, the cover plate assembly 100 of this embodiment can have sufficient welding strength, and 10 groups of tests are carried out. Refer to Table 1 below:

[0069] In Table 1, Test Examples 1 to 10 are tested based on the structure of the cover plate assembly 100 of this embodiment, that is, for the cover plate assemblies 100 of Test Examples 1 to 10, the width W of the pressure plate 3 1 、the thickness t of the pressure plate 3 1 、the width W of the flanging part 21 2 、and the thickness t of the flanging part 21 2 Satisfy the above matching relationship. Comparative Examples 1 to 2 are other cover plate assembly structures, that is, the width W of the pressure plate 3 of Comparative Examples 1 to 2 1 、the thickness t of the pressure plate 3 1 、the width W of the flanging part 21 2 、and the thickness t of the flanging part 21 2 Do not satisfy the above matching relationship.

[0070] The method for testing the tensile value is as follows: For each group of experiments, 20 batteries are taken. A tensile block is assembled on the surface of the terminal post 2, and the tensile block is connected to a tensile testing machine (model: universal testing machine DNS-2). After fixing the pressing ring 3, the tensile testing machine pulls the terminal post 2 through the tensile block, and the sensor of the tensile testing machine (sensor model: CLY30) is turned on to collect the tensile value of the tensile block until the terminal post 2 falls off. Read the maximum value in the tensile value curve. If the maximum value in the tensile value curve is above 1200N, it is qualified.

[0071] The method for testing the thermal conductivity is as follows: For each group of experiments, 20 batteries are taken. The current source (RDTS-02) is placed on the upper and lower surfaces of the terminal post, and the thermometer (LR8450) is placed on the lower surface of the terminal post 2. A current of 500A is passed through. After 1 minute, the temperature data is collected by the thermometer. 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 H of the first metal layer 20 1 , the thickness H of the second metal layer 21 2 , and the depth H of the welding mark 5 3 satisfy the above matching relationship, the terminal post 2 of the cover plate assembly 100 can withstand a tensile force of more than 1200N, ensure airtightness, and the thermal conductivity meets the requirements. When the thickness H of the first metal layer 20 1 , the thickness H of the second metal layer 21 2 , and the depth H of the welding mark 5 3 do not satisfy the above matching relationship, this type of cover plate assembly will have problems such as insufficient tensile force that the terminal post 2 can withstand, insufficient airtightness, or insufficient thermal conductivity.

[0076] When the pressing plate 3 is welded to the terminal post 2, the welding origin is near the intersection position of the pressing plate 3 and the first metal layer 20 on the front side of the terminal post 2, so that the pressing plate 3 is welded and fixed to the first metal layer 20. Since the melting point of the second metal layer 21 is higher than that of the first metal layer 20, therefore, when the pressing plate 3 is welded and fixed to the first metal layer 20, the second metal layer 21 will not melt, ensuring the stability of the overall structure of the terminal post 2 and the stable connection between the terminal post 2 and the battery cell.

[0077] It can be understood that the first metal layer 20 and the second metal layer 21 can be selected according to the specification parameters of the terminal post 2. For example, considering the applicability of laser welding, the first metal layer 20 can be aluminum, and the second metal layer 21 can be copper. Moreover, the pressing plate 3 can be made of the same material as the first metal layer 20, which is convenient for welding operation and temperature control during the welding process. For example, when the first odd layer is aluminum, the pressing plate 3 can also be made of aluminum.

[0078] The heat generated by welding will be transferred outward through the pressing plate 3 and the first metal layer 20. During the heat transfer process, since the heat conduction rate 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 moreover, as a structural layer made of metal material, the heat conduction rate of the second metal layer 21 is necessarily much greater than that of the insulating part 4. In this way, more heat generated by welding will be transferred to the second metal layer 21, enabling the second metal layer 21 to quickly take away the heat generated by welding and preventing excessive heat from being transferred to the insulating part 4, which may cause the insulating part 4 to overheat and soften, thus affecting the insulation effect.

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

[0080] For a power battery, the thickness and diameter of the terminal post 2 will have corresponding standard sizes. Therefore, the thickness H of the first metal layer 20 1 and the thickness H of the second metal layer 21 2 affect each other. If the thickness H of the first metal layer 20 1 is relatively large, although it can ensure the welding strength between the terminal post 2 and the pressing plate 3, correspondingly, the thickness H of the second metal layer 21 2 will be relatively small, which affects the rapid heat dissipation; correspondingly, if the thickness H of the second metal layer 21 2 is relatively large, although it can ensure the heat conduction effect of the terminal post 2, correspondingly, the thickness H of the first metal layer 20 1 will be relatively small, resulting in a corresponding reduction in the depth of the welding mark 5, which affects the welding strength between the terminal post 2 and the pressing plate 3. Therefore, the thickness H of the first metal layer 20 1 and the thickness H of the second metal layer 21 2, the depth of the welding mark 5 is H 3 It should meet a certain range value and conform to the corresponding ratio relationship.

[0081] For example, the thickness H of the first metal layer 20 1 can satisfy: 2 ≤ H 1 ≤ 4mm, so that the first metal layer 20 has sufficient thickness, ensuring that when the pressure plate 3 is welded to the first metal layer 20, the welding mark 5 generated can have sufficient depth. Exemplarily, the thickness H of the first metal layer 20 1 can adopt one of the sizes of 2mm, 2.5mm, 3mm, 3.5mm, 4mm.

[0082] Or, the thickness H of the second metal layer 21 2 can satisfy: 1 ≤ H 2 ≤ 2mm, so that the second metal layer 21 has sufficient thickness, ensuring that the pole 2 can evacuate the heat generated by welding in time. Exemplarily, the thickness H of the second metal layer 21 2 can adopt one of the sizes of 1mm, 1.5mm, 2mm.

[0083] Or, the depth of the welding mark 5 is H 3 can satisfy: 0.4 ≤ H 3 ≤ 2mm, to ensure that there is sufficient welding area between the pressure plate 3 and the pole 2, making the connection between the pressure plate 3 and the pole 2 stable. Exemplarily, the depth H of the welding mark 5 3 can adopt one of the sizes of 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] After 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 pressure plate 3 to ensure the heat conduction transfer efficiency.

[0085] Reference Figure 3, as an example of this embodiment, the cover plate assembly 100 may further include a seal 6. The seal 6 is disposed between the cover plate 1 and the pole column 2, arranged at the rear side of the insulating member 4, and at least partially disposed in the mounting hole, 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 column 2 and the cover plate 1. The specification dimensions of the seal 6 can be configured according to the specification dimensions 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, facilitating the cooperation between the insulating member 4 and the seal 6, and enabling the cover plate assembly 100 to obtain better sealing and insulating effects.

[0086] Generally speaking, in the area in the same welding direction as the welding mark 5, the heat-receiving condition is more obvious than other areas. At the position where the seal 6 contacts the pole column 2, it is easy to cause the seal 6 to melt and result in seal failure. In this regard, the thickness H of the first metal layer 20 can be considered for adjustment. 1 , the thickness H of the second metal layer 21 2 , the depth H of the welding mark 5 3 of the mutual relationship, so that the three satisfy:

[0087]

[0088] to reduce the influence of the heat generated by welding on the seal 6.

[0089] Exemplarily, the thickness H of the first metal layer 20 1 , the thickness H of the second metal layer 21 2 , the depth H of the welding mark 5 3 The ratio of the three based on formula (2) can be one of the values 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 forward along its thickness direction to form a recess 210, so that the second metal layer 21 forms an outer contour structure similar to a "ji" character. Utilizing the hollow structure formed by the recess 210 can effectively expand the heat dissipation area where the second metal layer 21 contacts the outside, and timely dissipate the heat of the second metal layer 21.

[0091] It can be understood that the thickness H of the second metal layer 21 2 affects the heat conduction performance of the second metal layer 21. The thickness H of the second metal layer 21 2 is larger, 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 correspondingly improved. Of course, the depth of the recess 210 also 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 H of the second metal layer 21 2 and the depth of the recess 210 should be maintained within a suitable range. For example, the depth of the recess 210 is H 4 , and the depth H of the recess 210 4 and the thickness H of the second metal layer 21 2 satisfy:

[0092]

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

[0094] Exemplarily, the depth H of the recess 210 4 and the thickness H of the second metal layer 21 2The ratio of the two based on formula (3) can be one of the values 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, 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 generally adheres to the rear side surface 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 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 more, easily causing 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 dissipated to the second metal layer 21 in time.

[0096] Reference 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 surface of the pressing plate 3, and the thickness H of the first metal layer 20 1 , the thickness H of the second metal layer 21 2 , the depth H of the solder mark 5 3 Satisfy:

[0097]

[0098] It can be understood that the interface 22 between the first metal layer 20 and the second metal layer 21 being flush with the rear side surface of the pressing plate 3 can make the second metal layer 21 close to the pressing plate 3. In this way, when the heat energy diffuses backward from the solder mark 5, more heat energy will diffuse to the second metal layer 21, enabling the heat of the pressing plate 3 to be dissipated to the second metal layer 21 in time.

[0099] Exemplarily, the thickness H of the first metal layer 20 1 , the thickness H of the second metal layer 21 2 , the depth H of the solder mark 5 3 The ratio of the three based on formula (4) can be one of the values 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, 4.3.

[0100] Or, reference 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 in front of the rear side surface of the pressing plate 3, so that the second metal layer 21 and the pressing plate 3 can form direct contact, and the thickness H of the first metal layer 201 、The thickness H of the second metal layer 21 2 、The depth H of the solder mark 5 3 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 in front 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 backward from the solder mark 5, more heat energy diffuses to the second metal layer 21, enabling the heat of the pressure plate 3 to be evacuated to the second metal layer 21 in a timely manner.

[0103] Exemplarily, the thickness H of the first metal layer 20 1 , the thickness H of the second metal layer 21 2 , the depth H of the solder mark 5 3 The ratio of the three based on formula (5) can be one of the values 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 H of the first metal layer 20 1 and the thickness H of the second metal layer 21 2 determine the junction position between the first metal layer 20 and the second metal layer 21. In the thickness direction of the terminal post 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 pressure plate 3 can reflect the contact area between the pressure plate 3 and the second metal layer 21 and the contact area between the pressure 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 pressure plate 3 is too small, the second metal layer 21 may not be able to evacuate the heat generated by welding in a timely manner; 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 pressure plate 3 is too large, it may lead to insufficient contact area between the first metal layer 20 and the pressure plate 3, affecting the welding strength. Therefore, in the thickness direction of the terminal post 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 pressure plate 3 is L 1 , L 1 can be considered to satisfy: 0 ≤ L 1 ≤ 1.5 mm. 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 pressure plate 3 is L1 One of the dimensions of 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 can be adopted.

[0105] Of course, in addition to adjusting the relative positional relationship between the second metal layer 21 and the pressing plate 3, the relative positional 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 dissipated by the second metal layer 21 in a timely manner. For example, at least a part of the insulating member 4 is connected to the outer peripheral side of the second metal layer 21.

[0106] Reference Figure 4 , as an example of this embodiment, the insulating member 4 may include a planar portion 40 and a vertical portion 41. Among them, the planar portion 40 is disposed between the pressing plate 3 and the cover plate 1 to separate the pressing 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 disposed opposite to the outer peripheral side of the second metal layer 21 to be in contact with the second metal layer 21.

[0107] Of course, the insulating member 4 can also be configured with a structure having other shape profiles according to the specifications of the cover plate assembly 100 itself, so that a part of the structure of the insulating member 4 itself can be connected to the outer peripheral side of the second metal layer 21, so that the insulating member 4 and the second metal layer 21 are directly connected, and the insulating member 4 can have a heat conduction effect with the second metal layer 21.

[0108] It can be understood that the heat resistance performance of the insulating member 4 will also affect the performance of the terminal post 2. The better the heat resistance performance of the insulating member 4, the less likely it is to soften during the welding of the terminal post 2 and the pressing plate 3. Correspondingly, the thickness of the second metal layer 21 of the terminal post 2 can also be reduced accordingly. As an example of this embodiment, the heat distortion temperature of the insulating member 4 is T, and T satisfies: 150°C ≤ T ≤ 350°C. In this case, the thickness H of the first metal layer 20 1 , the thickness H of the second metal layer 21 2 , the depth H of the welding mark 5 3 can satisfy:

[0109]

[0110] It can be understood that the heat distortion temperature T of the insulating member 4 reflects the heat resistance degree of the insulating member 4. The better the heat resistance degree of the insulating member, the greater the welding heat allowed to be generated between the pressing plate 3 and the terminal post 2, and the depth H of the welding mark 5 3The larger it can be, the better the connection strength between the pressure plate 3 and the pole column 2. Exemplarily, the heat distortion temperature T of the insulating part 4 can adopt one of the values of 150°C, 175°C, 200°C, 250°C, 275°C, 300°C, 325°C, 350°C.

[0111] Exemplarily, the thickness H of the first metal layer 20 1 , the thickness H of the second metal layer 21 2 , the depth H of the welding mark 5 3 The ratio of the three based on formula (6) can be one of the values 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, 8.

[0112] In addition to the heat dissipation performance of the pole column 2 affecting the heat borne by the insulating part 4, the welding mark 5, as the area directly affected by the welding process, is generally the area with the highest heat. If the welding mark 5 is too close to the insulating part 4, it will also cause the heat borne by the insulating part 4 to increase, resulting in the softening of the insulating part 4. Therefore, referring to Figure 6 , as an example of this embodiment, in the thickness direction of the pole column 2, the shortest vertical distance L from the connection surface between the rear side of the pressure plate 3 and the insulating part 4 to the welding mark 5 2 , and L 2 satisfies: 0 ≤ L 2 ≤ 2.5 mm. Exemplarily, the shortest vertical distance L from the connection surface between the rear side of the pressure plate 3 and the insulating part 4 to the welding mark 5 2 can adopt one of the dimensions of 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm.

[0113] Based on the above cover assembly 100, this embodiment further provides a battery (not shown in the figure), which includes a tab (not shown in the figure) and any one of the foregoing cover assemblies 100. The tab is arranged at the rear side of the cover 1, close to the second metal layer 21, and is electrically connected to the pole column 2.

[0114] Considering that the position where the tab is arranged may be behind the welding mark 5, causing the projection of the tab and the welding mark 5 to partially overlap in the thickness direction of the terminal 2. In this case, the heat generated by welding may affect the tab. Therefore, the thickness H of the first metal layer 20 1 and the thickness H of the second metal layer 21 2 and the depth H of the welding mark 5 3 can satisfy:

[0115]

[0116] To increase the thickness of the second metal layer 21 so that the second metal layer 21 can dissipate heat quickly.

[0117] Exemplarily, the thickness H of the first metal layer 20 1 , the thickness H of the second metal layer 21 2 , and the depth H of the welding mark 5 3 The ratio of the three based on formula (7) can be one of the values 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, 8.

[0118] In summary, the embodiment of the present application provides a cover plate assembly 100 and a battery. By using a terminal 2 composed of a composite of a first metal layer 20 and a second metal layer 21, and making the melting point of the first metal layer 20 less than the melting point of the second metal layer 21, and the heat conduction rate of the second metal layer 21 greater than the heat conduction rate of the first metal layer 20 and greater than the heat conduction rate of the pressing plate 3. In this way, when the pressing 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 welding more quickly, thereby reducing the heat transferred to the insulating part 4 and avoiding overheating and softening of the insulating part 4. Moreover, the thickness H of the first metal layer 20 1 and the thickness H of the second metal layer 21 2 will affect the welding strength and the heat conduction effect of the terminal 2. By controlling the relative ratio of the thickness H of the first metal layer 20 1 , the thickness H of the second metal layer 21 2 , and the depth H of the welding mark 5 3 of the three parameters, the cover plate assembly 100 can make the welding strength and the heat conduction effect reach a matching effect, so that the cover plate assembly 100 has both sufficient welding strength and can achieve the expected heat conduction effect.

[0119] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and substitutions can be made, and these improvements and substitutions should also be regarded as the protection scope 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; characterized in that: 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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