Battery cover plate assembly and battery

Abstract

A battery cover plate assembly and a battery. The battery cover plate assembly comprises a cover plate (2), a copper-aluminum composite terminal post (1) and an insulating member, wherein the copper-aluminum composite terminal post (1) comprises a tab welding section (111), an output section (13) and a connecting section (12), a plurality of protrusions (112) configured to be welded to a tab (72) being provided on the end face of the end of the tab welding section (111) close to the tab (72), and the connecting section (12) connecting the end of the tab welding section (111) away from the tab (72) to the output section (13); the cover plate (2) is provided with a through hole, and the connecting section (12) at least partially passes through the through hole; and the insulating member is arranged on the periphery of the copper-aluminum composite terminal post (1) and passes through the through hole, such that the copper-aluminum composite terminal post (1) is insulated from the cover plate (2). The copper-aluminum composite terminal post (1) comprises a copper layer and an aluminum layer, wherein the side close to the tab (72) is the copper layer, and the side away from the tab (72) is the aluminum layer; the copper layer comprises a copper layer main body and the protrusions (112); and the thickness of the copper layer main body is a, the thickness of the aluminum layer is b, the distance between the orthographic projections of adjacent protrusions (112) on the end face of the end of the tab welding section (111) close to the tab (72) is L, and 0.009≤(a / b) / L≤3. When (a / b) / L satisfies the range, the problem of the aluminum layer and the insulating member being easily deformed and melted when the copper-aluminum composite terminal post (1) is welded to the tab (72) can be solved.

Description

Battery cover assembly and battery

[0001] This application claims priority to Chinese Patent Application No. 202411746538.7, filed on December 2, 2024, entitled “Battery Cover Assembly and Battery”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of battery technology, and in particular to a battery cover assembly and a battery. Background Technology

[0003] Welding the battery tabs to the battery terminals can easily cause deformation and melting of the insulating components or the lower melting point parts of the terminals. How to avoid this is a technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0004] To address the aforementioned technical problems, this application provides a battery cover assembly, comprising a cover plate, a copper-aluminum composite electrode post, and an insulating component. The copper-aluminum composite electrode post includes a tab welding section, an output section, and a connecting section. The tab welding section has multiple protrusions on its end face near the tab for welding to the tab, the protrusions being spaced apart from each other. The output section is used to connect to a conductive component other than the battery. The connecting section connects the end of the tab welding section away from the tab and the output section. The cover plate has a through hole, and the connecting section... The insulating element is disposed on the outer periphery of the electrode post and passes through the through hole, thereby insulating the electrode post from the cover plate. The copper-aluminum composite electrode post includes a copper layer and an aluminum layer. The copper layer is located on the side closer to the electrode tab, and the aluminum layer is located on the side farther from the electrode tab. The copper layer includes a copper layer body and the protrusion. The thickness of the copper layer body is a, and the thickness of the aluminum layer is b. The distance between the orthographic projections of adjacent protrusions on the end face of the electrode tab welding section near the electrode tab is L, and 0.009≤(a / b) / L≤3.

[0005] One embodiment of the battery cover assembly is 0.07≤a / b≤3.

[0006] One embodiment of the battery cover assembly has a diameter of 0.4mm ≤ a ≤ 3mm.

[0007] One embodiment of the battery cover assembly is 1mm≤b≤6mm.

[0008] One embodiment of the battery cover assembly has a thickness of 1mm ≤ L ≤ 8mm.

[0009] In one embodiment of the battery cover assembly, the connecting segment includes a first connecting segment (121) and a second connecting segment (122). The first connecting segment connects to the tab welding segment, and the second connecting segment connects the first connecting segment and the output segment. The first connecting segment at least partially passes through the through hole. The interface between the copper layer and the aluminum layer is a copper-aluminum composite interface. The copper-aluminum composite interface is located at the interface between the first connecting segment and the tab welding segment, and 1mm≤L≤5mm.

[0010] In one embodiment of the battery cover assembly, the connecting segment includes a first connecting segment and a second connecting segment. The first connecting segment connects to the tab welding segment, and the second connecting segment connects the first connecting segment and the output segment. The first connecting segment at least partially passes through the through hole. The interface between the copper layer and the aluminum layer is a copper-aluminum composite interface. The copper-aluminum composite interface is located at the interface between the first connecting segment and the second connecting segment, and 1mm≤L≤3mm.

[0011] In one embodiment of the battery cover assembly, the distance between the copper-aluminum composite interface and the cover in the thickness direction of the cover is D, where 0.5mm≤D≤3mm.

[0012] In one embodiment of the battery cover assembly, the thickness of the insulating member between the end face of the electrode welding section away from the electrode and the side of the cover plate near the electrode is X, where 0.3mm≤X≤5mm.

[0013] One embodiment of the battery cover assembly, wherein the terminal post is cold-forged.

[0014] In one embodiment of a battery cover assembly, the battery cover assembly includes an output member, a first step surface and a second step surface are formed between the first connecting segment and the second connecting segment and between the second connecting segment and the output segment, respectively, and the outer peripheral surfaces of the first step surface, the second step surface and the second connecting segment enclose a riveting groove, and the output member is riveted to the terminal post through the riveting groove.

[0015] This application also provides a battery, including the battery cover assembly described in any of the above claims, and further including a battery cell and a housing, wherein the housing is connected to the top side of the cover and together with the cover to form a receiving cavity, the battery cell is located in the receiving cavity, and the battery cell includes a battery cell body and a tab extending from the battery cell body.

[0016] This application can ensure that the aluminum layer and insulation of the electrode post will not deform or melt due to the welding of the electrode post and the tab, and can also ensure that the current flow area is sufficient after the electrode post and the tab are welded. Attached Figure Description

[0017] Figure 1 is a perspective view of one embodiment of the pole post;

[0018] Figure 2 is a plan view of Figure 1;

[0019] Figure 3 is a plan view of another embodiment of the pole post;

[0020] Figure 4 is a partial 3D view of the battery cover assembly;

[0021] Figure 5 is a cross-sectional view of Figure 4;

[0022] Figure 6 is an exploded view of the battery.

[0023] The reference numerals in the attached drawings are explained as follows: 1 pole post, 111 electrode tab welding section, 111a body, 111b boss, 112 protrusion, 12 connecting section, 121 first connecting section, 122 second connecting section, 13 output section, 2 cover plate, 3 first insulating part, 4 second insulating part, 5 output component, 6 housing, 7 battery cell, 71 battery cell body, 72 electrode tab. Detailed Implementation

[0024] To enable those skilled in the art to better understand the technical solutions of this application, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] This application provides a battery cover assembly and a battery.

[0026] The battery cover assembly provided in this application includes a cover plate 2, a copper-aluminum composite terminal post 1, and an insulating component. As shown in Figures 1-3, the copper-aluminum composite terminal post 1 includes a tab welding section 111, an output section 13, and a connection section 12.

[0027] The electrode welding section 111 has multiple protrusions 112 on its end face near the electrode 72 for welding with the electrode 72. The multiple protrusions 112 are spaced apart from each other. "Multiple" means two or more; in the figure, there are ten. The protrusions 112 are preferably made of the same material as the electrode 72 to avoid electrochemical corrosion between different materials. The surface of the protrusions 112 is preferably a smooth surface, as a smooth surface is less likely to damage the electrode 72 during welding. For example, the smooth surface can be a sphere or an ellipsoid; in the figure, the surface of the protrusion 112 is a sphere. In the figure, the electrode welding section 111 has a body 111a and a boss 111b. The boss 111b protrudes from the end face of the body 111a away from the electrode 72, and the diameter of the boss 111b is smaller than the diameter of the body 111a.

[0028] Connecting segment 12 connects the end of tab welding segment 111 away from tab 72 to output segment 13. Output segment 13 is used to connect to conductive components other than the battery. Exemplarily, the connection method can be welding or riveting. Output segment 13 and the conductive component connected thereto are preferably made of the same material to avoid electrochemical corrosion between different materials.

[0029] As shown in Figure 4, the cover plate 2 has a through hole, and the connecting section 12 passes through the through hole at least partially. An insulating element is provided on the outer periphery of the pole post 1 and passes through the through hole. The insulating element insulates the pole post 1 from the cover plate 2 and also serves as a seal.

[0030] The copper-aluminum composite electrode post 1 includes a copper layer and an aluminum layer. The side closer to the electrode tab 72 is the copper layer, and the side farther from the electrode tab 72 is the aluminum layer. The copper layer includes a copper layer body and the aforementioned protrusions 112. The thickness of the copper layer body is 'a', and the thickness of the aluminum layer is 'b'. The distance between the orthographic projections of adjacent protrusions 112 on the end face of the electrode tab welding section 111 near the electrode tab 72 is L, where 0.009 ≤ (a / b) / L ≤ 3. Exemplarily, it can be equal to 0.009, 0.1, 0.5, 1, 1.5, 2, 2.5, or 3. Specifically, the range of 'a' can be: 0.4 mm ≤ a ≤ 3 mm. Exemplarily, it can be equal to 0.4 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, or 3 mm. Specifically, the range of 'b' can be: 1 mm ≤ b ≤ 6 mm. Exemplarily, it can be equal to 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, or 6 mm.

[0031] To ensure sufficient flow area after welding the copper-aluminum composite electrode post 1 to the tab 72, the end face area of ​​the tab welding section 111 needs to be relatively large. This results in a large volume of the tab welding section 111, causing the welding heat to be more dispersed within it, making it difficult to melt. To melt the tab welding section 111, the welding time or welding power needs to be increased to increase the welding heat. However, increased welding heat may cause deformation and melting of the aluminum layer of the copper-aluminum composite electrode post 1 (because the melting point of aluminum is lower than that of copper), and may also cause deformation and melting of the insulating components around the electrode post 1, leading to insulation seal failure. By providing multiple protrusions 112 at intervals on the end face of the tab welding section 111 near the tab 72, the protrusions 112 are smaller and therefore melt more easily than the tab welding section 111, thus reducing the welding heat. The easier the protrusions 112 melt, the less welding heat is generated, and the less welding heat is generated, the lower the probability of deformation and melting of the aluminum layer and insulating components during welding.

[0032] The greater the distance L between the orthographic projections of adjacent protrusions 112 on the end face of the electrode welding section 111 near the electrode 72, the easier it is for welding heat to be transferred to the protrusions 112, making the protrusions 112 easier to melt. When the thickness b of the aluminum layer is constant, the greater the ratio (a / b) of the thickness of the copper layer to the thickness of the aluminum layer, the greater the thickness a of the copper layer. The greater the thickness a of the copper layer, the more welding heat diffuses in the copper layer, resulting in less welding heat reaching the protrusions 112, making the protrusions 112 less likely to melt. The smaller the ratio of a / b to L, the smaller a / b and the larger L, therefore the smaller the ratio of a / b to L, the easier it is for the protrusions 112 to melt, which is more conducive to reducing welding heat. However, the ratio of a / b to L cannot be too small. If it is too small, it means that a / b is very small and L is very large. If L is very large, there will be very few protrusions 112. After the protrusions 112 and the tab 72 are welded, the connection strength will be insufficient and the current-carrying area will be insufficient, affecting the current-carrying capacity and reliability of the battery. Controlling the ratio of a / b to L within the range of 0.009-3 can ensure that the aluminum layer and insulating components do not deform or melt due to the welding of the terminal post 1 and the tab 72, and can also ensure that the current-carrying area is sufficient after the terminal post 1 and the tab 72 are welded.

[0033] In some embodiments, 0.07 ≤ a / b ≤ 3, and exemplarily, it can be equal to 0.07, 0.1, 0.5, 1, 1.5, 2, 2.5, or 3. Controlling the ratio of the thickness 'a' of the copper layer to the thickness 'b' of the aluminum layer within the range of 0.07-3 ensures that the thickness 'a' of the copper layer is neither too large nor too small. If the thickness 'a' of the copper layer is too large, it will hinder the melting of the protrusion 112; if the thickness 'a' of the copper layer is too small, the welding heat will easily be transferred to the aluminum layer and the insulating component during welding, easily causing deformation and melting of the aluminum layer and the insulating component.

[0034] In some embodiments, 1mm ≤ L ≤ 8mm, which can be exemplarily equal to 1mm, 3mm, 5mm, or 8mm. This ensures that the spacing between adjacent protrusions 112 is neither too large nor too small. If the spacing is too large, the number of protrusions 112 will be too small, which is detrimental to the connection strength and current carrying capacity with the tab 72. If the spacing is too small, it will hinder the melting of the protrusions 112, and after welding, the weld slag at the edges of adjacent protrusions 112 will fuse together, resulting in an uneven surface and affecting the connection strength with the tab 72.

[0035] In some embodiments, as shown in FIG2, the connecting segment 12 includes a first connecting segment 121 and a second connecting segment 122. The first connecting segment 121 is connected to the tab welding segment 111, and the second connecting segment 122 is connected to the first connecting segment 121 and the output segment 13. The first connecting segment 121 at least partially passes through the through hole on the cover plate 2. The interface between the copper layer and the aluminum layer is a copper-aluminum composite interface. The copper-aluminum composite interface is located at the interface between the first connecting segment 121 and the tab welding segment 111. 1mm≤L≤5mm, for example, can be equal to 1mm, 2mm, 3mm, 4mm, or 5mm. The copper-aluminum composite interface is located at the interface between the first connecting section 121 and the electrode welding section 111, which makes the thickness a of the copper layer body relatively small, making the protrusion 112 easier to melt. Therefore, the value of L can be smaller, so L≤5mm is controlled. However, L cannot be too small, otherwise the protrusion 112 will not melt easily, and the weld slag at the edges of adjacent protrusions 112 will melt together after welding, resulting in an uneven surface and affecting the connection strength with the electrode 72. Therefore, L is controlled to be 1mm≤1mm.

[0036] In some embodiments, as shown in FIG3, the connecting segment 12 includes a first connecting segment 121 and a second connecting segment 122. The first connecting segment 121 connects to the tab welding segment 111, and the second connecting segment 122 connects the first connecting segment 121 and the output segment 13. The first connecting segment 121 at least partially passes through the through hole in the cover plate. The interface between the copper layer and the aluminum layer is a copper-aluminum composite interface. The copper-aluminum composite interface is located at the interface between the first connecting segment 121 and the second connecting segment 122, and 1mm≤L≤3mm. For example, it can be equal to 1mm, 2mm, or 3mm. The copper-aluminum composite interface is located at the interface between the first connecting segment 121 and the second connecting segment 122, which makes the thickness 'a' of the main body of the copper layer relatively large. In order to ensure that the protrusion 112 is easily melted, the value of L needs to be larger. Therefore, 1mm≤L is controlled. At the same time, L cannot be too large, as an excessively large value is not conducive to the connection strength and current carrying capacity with the tab 72. Therefore, L≤3mm is controlled.

[0037] In some embodiments, the distance between the copper-aluminum composite interface and the cover plate 2 in the thickness direction is D, where 0.5mm ≤ D ≤ 3mm. By controlling D within the above range, it is ensured that D is neither too large nor too small. If D is too small, the cover plate 2 will exert a large force on the copper-aluminum composite interface, causing the electrode post 1 to easily break at the copper-aluminum composite interface. If D is too large, the electrode post 1 will occupy more of the internal or external space of the battery casing 6. If the electrode post 1 occupies more of the internal space of the battery casing 6, it will result in a low battery energy density. If the electrode post 1 occupies more of the external space of the battery casing 6, it will result in a large overall battery volume.

[0038] In some embodiments, the thickness of the insulating member between the end face of the tab welding section 111 away from the tab 72 and the side of the cover plate 2 near the tab 72 is X, where 0.3mm ≤ X ≤ 5mm. The portion of the insulating member between the tab welding section 111 and the cover plate 2 is closest to the tab 72, so the greater the thickness of this portion, the less likely the entire insulating member is to deform.

[0039] In some embodiments, the electrode post 1 is cold-forged. If the copper layer and aluminum layer are welded together by friction welding (friction welding uses the heat generated by the relative motion and friction of two workpieces pressed together to fuse them together), the protrusion 112 will be worn or even flattened during the friction welding process, while cold forging can avoid this problem. In addition, the cold-forged electrode post 1 has lower internal resistance, which is more conducive to improving the current carrying capacity of the electrode post 1.

[0040] In some embodiments, the battery cover assembly further includes an output component 5, with a first step surface and a second step surface formed between the first connecting segment 121 and the second connecting segment 122, and between the second connecting segment 122 and the output segment 13, respectively. The first step surface, the second step surface, and the outer peripheral surface of the second connecting segment 122 enclose a riveting groove, and the output component 5 is riveted to the pole post 1 through the riveting groove.

[0041] In some embodiments, the insulating element includes a first insulating portion 3 and a second insulating portion 4, which can be independent of each other or integrated together. Each copper-aluminum composite pole 1 has a first insulating portion 3 disposed on its outer periphery. A portion of the first insulating portion 3 is located in the through hole of the cover plate 2, and a portion is located between the side of the cover plate 2 near the tab 72 and the end face of the tab welding section 111 away from the tab 72. The second insulating portion 4 is at least partially located between the output member 5 and the side of the cover plate 2 away from the tab 72, thus insulating the output member 5 from the cover plate 2.

[0042] The battery provided in this application includes the aforementioned battery cover assembly, and further includes a battery cell 7 and a housing 6. The housing 6 is connected to the side of the cover 2 near the tab 72, and together with the cover 2, forms a receiving cavity, within which the battery cell 7 is located. The battery cell 7 includes a battery cell body 71 and tabs 72 extending from the battery cell body 71. Specifically, the battery cell body 71 includes a positive electrode and a negative electrode, which are arranged alternately, with a separator between adjacent positive and negative electrode pieces. The positive and negative electrode pieces have similar structures, both including a conductive layer and an active material layer coated on the conductive layer. The portion of the conductive layer of the positive electrode piece that is not coated with active material protrudes beyond the portion coated with active material to form a single positive electrode tab, and multiple single positive electrode tabs are stacked to form a positive electrode tab. Similarly, the portion of the conductive layer of the negative electrode piece that is not coated with active material protrudes beyond the portion coated with active material to form a single negative electrode tab, and multiple single negative electrode tabs are stacked to form a negative electrode tab.

[0043] The protrusion 112 of the copper-aluminum composite electrode post 1 is welded to the tab 72. Exemplarily, the welding method can be resistance welding, friction welding, ultrasonic welding, laser welding, etc. In some embodiments, the protrusion 112 and the tab 72 are welded by resistance welding. Resistance welding utilizes the resistive heat generated when a large current passes through the welding area of ​​the workpiece to overcome the workpiece's resistance, fusing the two workpieces together. A single resistance welding process can weld the multiple layers of tab 72 together, and simultaneously weld the tab 72 to the protrusion 112. Thus, before welding the tab 72 to the protrusion 112, it is not necessary to pre-weld the multiple layers of tab 72, eliminating the need for a pre-welding process.

[0044] The above examples illustrate the principles and implementation methods of this application. The descriptions of the embodiments are merely for the purpose of helping to understand the methods and core ideas of this application. It should be noted that those skilled in the art can make various improvements and modifications to this application without departing from its principles, and these improvements and modifications also fall within the protection scope of this application.

Claims

1. A battery cover assembly, characterized in that, The battery cover assembly includes a cover plate, a copper-aluminum composite terminal post, and an insulating component. The copper-aluminum composite terminal post includes a tab welding section, an output section, and a connecting section. The tab welding section has multiple protrusions on its end face near the tab for welding to the tab, with the protrusions spaced apart from each other. The output section is used to connect to a conductive component other than the battery. The connecting section connects the end of the tab welding section away from the tab to the output section. The cover plate has a through hole, and the connecting section at least partially passes through the through hole. The insulating component is located on the outer periphery of the terminal post and passes through the through hole, thus insulating the terminal post from the cover plate. The copper-aluminum composite terminal post includes a copper layer and an aluminum layer. The side near the tab is the copper layer, and the side away from the tab is the aluminum layer. The copper layer includes a copper layer body and the protrusions. The thickness of the copper layer body is 'a', and the thickness of the aluminum layer is 'b'. The distance between the orthographic projections of adjacent protrusions on the end face of the tab welding section near the tab is L, where 0.009 ≤ (a / b) / L ≤ 3.

2. The battery cover assembly according to claim 1, characterized in that, 0.07≤a / b≤3.

3. The battery cover assembly according to claim 1, characterized in that, 0.4mm≤a≤3mm.

4. The battery cover assembly according to claim 1, characterized in that, 1mm≤b≤6mm.

5. The battery cover assembly according to claim 1, characterized in that, 1mm≤L≤8mm.

6. The battery cover assembly according to claim 1, characterized in that, The connecting segment includes a first connecting segment and a second connecting segment. The first connecting segment connects to the tab welding segment, and the second connecting segment connects the first connecting segment and the output segment. The first connecting segment at least partially passes through the through hole. The interface between the copper layer and the aluminum layer is a copper-aluminum composite interface. The copper-aluminum composite interface is located at the interface between the first connecting segment and the tab welding segment, and 1mm≤L≤5mm.

7. The battery cover assembly according to claim 1, characterized in that, The connecting segment includes a first connecting segment and a second connecting segment. The first connecting segment connects to the electrode welding segment, and the second connecting segment connects the first connecting segment and the output segment. The first connecting segment at least partially passes through the through hole. The interface between the copper layer and the aluminum layer is a copper-aluminum composite interface. The copper-aluminum composite interface is located at the interface between the first connecting segment and the second connecting segment, and 1mm≤L≤3mm.

8. The battery cover assembly according to claim 1, characterized in that, In the thickness direction of the cover plate, the distance between the copper-aluminum composite interface and the cover plate is D, where 0.5mm≤D≤3mm.

9. The battery cover assembly according to claim 1, characterized in that, The thickness of the insulating component between the end face of the electrode welding section away from the electrode and the side of the cover plate near the electrode is X, where 0.3mm≤X≤5mm.

10. The battery cover assembly according to claim 1, characterized in that, The pole is cold-forged.

11. The battery cover assembly according to claim 1, characterized in that, The battery cover assembly includes an output component. The connecting segment includes a first connecting segment and a second connecting segment. The first connecting segment connects to the electrode welding segment, and the second connecting segment connects the first connecting segment and the output segment. The first connecting segment at least partially passes through the through hole. A first step surface and a second step surface are formed between the first connecting segment and the second connecting segment, and between the second connecting segment and the output segment, respectively. The first step surface, the second step surface, and the outer peripheral surface of the second connecting segment enclose a riveting groove. The output component is riveted to the electrode post through the riveting groove.

12. A battery, characterized in that, The battery cover assembly according to any one of claims 1-11 further includes a battery cell and a housing, the battery cell including a cell body and a tab extending from the cell body, the housing being connected to the side of the cover near the tab and together with the cover to form a receiving cavity, the battery cell being located within the receiving cavity.

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