Battery cover plate assembly and battery

Abstract

The invention provides a battery cover plate assembly and a battery, the battery cover plate assembly comprises a cover plate, a copper-aluminum composite pole and an insulating part, and the copper-aluminum composite pole comprises a tab welding section, an output section and a connecting section; a plurality of bulges welded with the tab are arranged on the end surface of one end, close to the tab, of the tab welding section, the connecting section is connected with one end, far away from the tab, of the tab welding section and the output section, a through hole is formed in the cover plate, the connecting section at least partially penetrates through the through hole, and the insulating part is arranged on the periphery of the pole and penetrates through the through hole, so that the pole is insulated from the cover plate; the copper-aluminum composite pole comprises a copper layer and an aluminum layer, the copper layer is arranged on the side close to the tab, the aluminum layer is arranged on the side away from the tab, the copper layer comprises a copper layer body and protrusions, the thickness of the copper layer body is a, the thickness of the aluminum layer is b, the distance between orthographic projections of the adjacent protrusions on the end face of the end, close to the tab, of the tab welding section is L, and (a / b) / L is larger than or equal to 0.009 and smaller than or equal to 3. The problem that an aluminum layer and an insulating part of the pole are deformed and melted when the pole and the pole lug are welded is solved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery cover assembly and a battery. Background Art

[0002] The welding of the battery's lugs and battery's poles can easily cause deformation and melting of the insulating parts or the parts of the poles with lower melting points. How to avoid this is a technical problem that needs to be solved by technicians in this field. Summary of the invention

[0003] In order to solve the above technical problems, the present application provides a battery cover assembly, the battery cover assembly includes a cover, a copper-aluminum composite pole and an insulating member, the copper-aluminum composite pole includes a pole ear welding section, an output section and a connecting section; the pole ear welding section is provided with a plurality of protrusions for welding with the pole ear on an end surface close to the pole ear, the plurality of protrusions are spaced apart from each other, the output section is used to connect with a conductive member other than a battery, the connecting section connects an end of the pole ear welding section away from the pole ear and the output section, the cover is provided with a through hole, the connecting section At least partially passes through the through hole, the insulating member is arranged on the outer periphery of the pole and passes through the through hole, so that the pole is insulated from the cover plate; the copper-aluminum composite pole includes a copper layer and an aluminum layer, the side close to the pole ear is the copper layer, and the side away from the pole ear is the aluminum layer, the copper layer includes a copper layer body and the protrusion, the thickness of the copper layer body is a, the thickness of the aluminum layer is b, the distance between the orthographic projections of adjacent protrusions on the end face of one end of the pole ear welding section close to the pole ear is L, 0.009≤(a / b) / L≤3.

[0004] An implementation manner of a battery cover assembly, 0.07≤a / b≤3.

[0005] An implementation manner of a battery cover assembly, 0.4mm≤a≤3mm.

[0006] An implementation manner of a battery cover assembly, 1mm≤b≤6mm.

[0007] An implementation manner of a battery cover assembly, 1mm≤L≤8mm.

[0008] An embodiment of a battery cover plate assembly, the connecting section comprises a first connecting section (121) and a second connecting section (122), the first connecting section is connected to the pole lug welding section, the second connecting section is connected to the first connecting section and the output section, the first connecting section 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 section and the pole lug welding section, 1mm≤L≤5mm.

[0009] In one embodiment of a battery cover plate assembly, the connecting section includes a first connecting section and a second connecting section, the first connecting section connects the pole ear welding section, the second connecting section connects the first connecting section and the output section, the first connecting section 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 section and the second connecting section, 1mm≤L≤3mm.

[0010] In one implementation manner of the battery cover plate assembly, in the thickness direction of the cover plate, the distance between the copper-aluminum composite interface and the cover plate is D, and 0.5mm≤D≤3mm.

[0011] In one embodiment of the battery cover plate assembly, the thickness of the insulating member between an end surface of the pole lug welding section away from the pole lug and a side surface of the cover plate close to the pole lug is X, and 0.3mm≤X≤5mm.

[0012] In one embodiment of the battery cover assembly, the pole is formed by cold heading.

[0013] An embodiment of a battery cover plate assembly, the battery cover plate assembly includes an output piece, a first step surface and a second step surface are respectively formed between the first connecting section and the second connecting section and between the second connecting section and the output section, the first step surface, the second step surface and the outer peripheral surface of the second connecting section are surrounded to form a rivet groove, and the output piece is riveted to the pole through the rivet groove.

[0014] The present application also provides a battery, comprising the battery cover assembly described in any one of the above items, and also comprising a battery cell and a shell, wherein the shell is connected to the top side of the cover plate and together with the cover plate forms a accommodating cavity, the battery cell is located in the accommodating cavity, and the battery cell comprises a battery cell body and a pole ear extending from the battery cell body.

[0015] The present application can ensure that the aluminum layer and the insulating member of the pole are not deformed and melted due to the welding of the pole and the pole lug, and can also ensure that the flow area is sufficient after the pole and the pole lug are welded. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A three-dimensional diagram of an embodiment of a pole;

[0017] Figure 2 for Figure 1 Floor plan of

[0018] Figure 3 A plan view of another embodiment of a pole;

[0019] Figure 4 It is a partial three-dimensional diagram of a battery cover assembly;

[0020] Figure 5 for Figure 4 A cross-sectional view of

[0021] Figure 6 An exploded view of the battery.

[0022] The following are the descriptions of the reference numerals:

[0023] 1 pole, 111 pole ear 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 member, 6 shell, 7 battery cell, 71 battery cell body, 72 pole ear. DETAILED DESCRIPTION

[0024] In order to enable those skilled in the art to better understand the technical solution of the present application, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0025] The present application provides a battery cover assembly and a battery.

[0026] The battery cover assembly provided in the present application includes a cover 2, a copper-aluminum composite pole 1 and an insulating member. Figure 1-Figure 3 As shown, the copper-aluminum composite pole 1 includes a pole lug welding section 111 , an output section 13 and a connecting section 12 .

[0027] A plurality of protrusions 112 for welding with the pole lug 72 are provided on the end surface of the pole lug welding section 111 close to the pole lug 72. The plurality of protrusions 112 are spaced apart from each other. A plurality refers to two or more than two, and ten are shown in the figure. The protrusion 112 is preferably made of the same material as the pole lug 72 to avoid electrochemical corrosion between different materials. The surface of the protrusion 112 is preferably a smooth surface, and the smooth surface is not easy to damage the pole lug 72 when welding with the pole lug 72. For example, the smooth surface can be a spherical surface or an ellipsoidal surface. In the figure, the surface of the protrusion 112 is a spherical surface. In the figure, the pole lug welding section 111 has a main body 111a and a boss 111b, and the boss 111b protrudes from the end surface of the main body 111a away from the pole lug 72, and the diameter of the boss 111b is smaller than the diameter of the main body 111a.

[0028] The connecting section 12 connects the end of the pole lug welding section 111 away from the pole lug 72 and the output section 13. The output section 13 is used to connect with a conductive member other than the battery. Exemplarily, the connection method can be welding or riveting. The output section 13 and the conductive member connected thereto are preferably made of the same material to avoid electrochemical corrosion between different materials.

[0029] like Figure 4As shown, the cover plate 2 is provided with a through hole, and the connecting section 12 at least partially passes through the through hole. The insulating member is arranged on the outer periphery of the pole 1 and passes through the through hole. The insulating member insulates the pole 1 from the cover plate 2 and also plays a sealing role.

[0030] The copper-aluminum composite pole 1 includes a copper layer and an aluminum layer, the side close to the pole ear 72 is the copper layer, and the side away from the pole ear 72 is the aluminum layer. The copper layer includes a copper layer body and the above-mentioned protrusion 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 surface of the pole ear welding section 111 close to the pole ear 72 is L, 0.009≤(a / b) / L≤3, illustratively, it can be equal to 0.009, 0.1, 0.5, 1, 1.5, 2, 2.5, 3. Specifically, the range of a can be: 0.4mm≤a≤3mm, illustratively, it can be equal to 0.4mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm. Specifically, the range of b can be: 1mm≤b≤6mm, illustratively, it can be equal to 1mm, 2mm, 3mm, 4mm, 5mm, 6mm.

[0031] In order to ensure that the copper-aluminum composite pole 1 has sufficient flow area after welding with the pole lug 72, the end surface area of ​​the pole lug welding section 111 needs to be relatively large, resulting in a relatively large volume of the pole lug welding section 111. During welding, the welding heat is relatively dispersed in the pole lug welding section 111, resulting in the pole lug welding section 111 being difficult to melt. To melt the pole lug welding section 111, it is necessary to increase the welding time or increase the welding power to increase the welding heat. The increase in welding heat may cause the aluminum layer of the copper-aluminum composite pole 1 to deform and melt (because the melting point of aluminum is lower than that of copper), and may also cause the insulating parts around the pole 1 to deform and melt, resulting in failure of the insulating seal. A plurality of protrusions 112 are arranged at intervals on the end surface of the pole lug welding section 111 close to the pole lug 72. The volume of the protrusions 112 is relatively small, so it is easier to melt than the pole lug welding section 111, so the welding heat can be controlled to be less. The easier the protrusions 112 are to melt, the less welding heat is, and the less welding heat is, the smaller the probability of deformation and melting of the aluminum layer and the insulating parts caused by welding.

[0032] The larger the distance L between the orthographic projections of adjacent protrusions 112 on the end surface of the pole lug welding section 111 close to the pole lug 72, the easier it is for the welding heat to be transferred to the protrusion 112, making the protrusion 112 more easily meltable. When the thickness b of the aluminum layer is constant, the larger the ratio (a / b) of the thickness of the copper layer body to the thickness of the aluminum layer, the larger the thickness a of the copper layer body, the more the welding heat diffuses in the copper layer body, resulting in less welding heat reaching the protrusion 112, making the protrusion 112 less likely to melt. The smaller the ratio of a / b to L, the smaller a / b and the larger L, so the smaller the ratio of a / b to L, the easier it is for the protrusion 112 to melt, and the more conducive to reducing welding heat. However, the ratio of a / b to L cannot be too small. Too small means that a / b is very small and L is very large. If L is very large, the number of protrusions 112 is small, and the connection strength and flow area of ​​the protrusions 112 after welding with the tabs 72 are insufficient, which affects the flow capacity and reliability of the battery. Controlling the ratio of a / b to L within the range of 0.009-3 can not only ensure that the aluminum layer and the insulating member are not deformed and melted due to the welding of the pole 1 and the tab 72, but also ensure that the flow area of ​​the pole 1 and the tab 72 is sufficient after welding.

[0033] In some embodiments, 0.07≤a / b≤3, illustratively, can be equal to 0.07, 0.1, 0.5, 1, 1.5, 2, 2.5, 3. The ratio of the thickness a of the copper layer body to the thickness b of the aluminum layer is controlled within the range of 0.07-3, which ensures that the thickness a of the copper layer body is neither too large nor too small. If the thickness a of the copper layer body is too large, it is not conducive to the melting of the protrusion 112. If the thickness a of the copper layer body is too small, the welding heat is easily transferred to the aluminum layer and the insulating member during welding, which easily causes the aluminum layer and the insulating member to deform and melt.

[0034] In some embodiments, 1mm≤L≤8mm, illustratively, can be equal to 1mm, 3mm, 5mm, 8mm. In this way, the spacing between adjacent protrusions 112 is neither too large nor too small. If the spacing between adjacent protrusions 112 is too large, the number of protrusions 112 is too small, which is not conducive to the connection strength and current capacity with the tab 72. If the spacing between adjacent protrusions 112 is too small, it is not conducive to the melting of the protrusions 112, and after welding, the edge slag of the adjacent protrusions 112 will melt together, resulting in an uneven surface, which affects the connection strength with the tab 72.

[0035] In some embodiments, Figure 2As shown, the connecting section 12 includes a first connecting section 121 and a second connecting section 122, the first connecting section 121 is connected to the pole ear welding section 111, the second connecting section 122 is connected to the first connecting section 121 and the output section 13, the first connecting section 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 section 121 and the pole ear welding section 111, 1mm≤L≤5mm, illustratively, it can be equal to 1mm, 2mm, 3mm, 4mm, 5mm. The copper-aluminum composite interface is located at the interface between the first connecting section 121 and the pole ear welding section 111, so that the thickness a of the copper layer body is smaller, making the protrusion 112 easier to melt, so the value of L can be smaller, so L is controlled to be less than 5mm, but L cannot be too small. If it is too small, the protrusion 112 will not be easy to melt, and the edge welding slag of adjacent protrusions 112 will melt together after welding, resulting in an uneven surface, affecting the connection strength with the pole ear 72. Therefore, 1mm≤L is controlled.

[0036] In some embodiments, such as Figure 3 As shown, the connection section 12 includes a first connection section 121 and a second connection section 122, the first connection section 121 connects the pole ear welding section 111, the second connection section 122 connects the first connection section 121 and the output section 13, the first connection section 121 at least partially passes through the through hole on 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 connection section 121 and the second connection section 122, 1mm≤L≤3mm, for example, it can be equal to 1mm, 2mm, 3mm. The copper-aluminum composite interface is located at the interface between the first connection section 121 and the second connection section 122, so that the thickness a of the copper layer body is relatively large. In order to ensure that the protrusion 112 is easy to melt, it is necessary to make the value of L larger, so 1mm≤L is controlled, and at the same time L cannot be too large, which is not conducive to the connection strength and current capacity with the pole ear 72, so L is controlled to be ≤3mm.

[0037] In some embodiments, in the thickness direction of the cover plate 2, the distance between the copper-aluminum composite interface and the cover plate 2 is D, 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 pole 1 to be easily disconnected at the copper-aluminum composite interface. If D is too large, the pole 1 will occupy more of the internal space of the battery shell 6 or the external space of the battery shell 6. The pole 1 occupying more of the internal space of the battery shell 6 will result in low battery energy density, and the pole 1 occupying more of the external space of the battery shell 6 will result in a large overall battery volume.

[0038] In some embodiments, the thickness of the insulating member between the end surface of the electrode tab welding section 111 away from the electrode tab 72 and the side surface of the cover plate 2 close to the electrode tab 72 is X, and 0.3 mm ≤ X ≤ 5 mm. The portion of the insulating member between the electrode tab welding section 111 and the cover plate 2 is closest to the electrode 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 pole 1 is formed by cold heading. If the copper layer and the aluminum layer are welded together by friction welding (friction welding is to use the heat generated by the friction of two workpieces pressed together and moving relative to each other to melt the two workpieces together), the protrusion 112 will be worn or even flattened during the friction welding process, while cold heading can avoid this problem. In addition, the pole 1 formed by cold heading has a lower internal resistance, which is more conducive to improving the current carrying capacity of the pole 1.

[0040] In some embodiments, the battery cover assembly also includes an output member 5, a first step surface and a second step surface are respectively formed between the first connecting section 121 and the second connecting section 122 and between the second connecting section 122 and the output section 13, the first step surface, the second step surface, the outer peripheral surface of the second connecting section 122 are surrounded to form a rivet groove, and the output member 5 is riveted to the pole 1 through the rivet groove.

[0041] In some embodiments, the insulating member includes a first insulating portion 3 and a second insulating portion 4, which may be independent of each other or integrated together. A first insulating portion 3 is provided on the periphery of each copper-aluminum composite pole 1. A portion of the first insulating portion 3 is located in the through hole of the cover plate 2, and a portion of the first insulating portion 3 is located between the side of the cover plate 2 close to the pole lug 72 and the end face of the pole lug welding section 111 away from the pole lug 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 pole lug 72, so that the output member 5 and the cover plate 2 are insulated from each other.

[0042] The battery provided in the present application includes the above-mentioned battery cover assembly, and also includes a battery cell 7 and a shell 6. The shell 6 is connected to the side of the cover 2 near the pole ear 72, and together with the cover 2, it encloses a receiving cavity, and the battery cell 7 is located in the receiving cavity. The battery cell 7 includes a battery cell body 71 and a pole ear 72 led out from the battery cell body 71. Specifically, the battery cell body 71 includes a positive electrode sheet and a negative electrode sheet, and the positive electrode sheet and the negative electrode sheet are arranged alternately one by one, and a diaphragm is provided between adjacent positive electrode sheets and negative electrode sheets. The structure of the positive electrode sheet and the negative electrode sheet is similar, and both include a conductive layer and an active material layer coated on the conductive layer. The part of the conductive layer of the positive electrode sheet that is not coated with the active material protrudes from the part that is coated with the active material to form a positive electrode ear monolithic sheet, and multiple layers of positive electrode ear monolithic sheets are stacked to form a positive electrode ear. The part of the conductive layer of the negative electrode sheet that is not coated with the active material protrudes from the part that is coated with the active material to form a negative electrode ear monolithic sheet, and multiple layers of negative electrode ear monolithic sheets are stacked to form a negative electrode ear.

[0043] The protrusion 112 of the copper-aluminum composite pole 1 is welded to the pole lug 72. Exemplarily, the welding method may be resistance welding, friction welding, ultrasonic welding, laser welding, etc. In some embodiments, the protrusion 112 and the pole lug 72 are welded by resistance welding, and resistance welding utilizes the resistance heat generated by overcoming the resistance of the workpiece when a large current passes through the welding area of ​​the workpiece to melt the two workpieces together. A single resistance welding process can weld together the multi-layer pole lug monolith of the pole lug 72, and can also weld the pole lug 72 and the protrusion 112 together. In this way, before welding the pole lug 72 and the protrusion 112, it is not necessary to pre-weld the multi-layer pole lug monolith of the pole lug 72, thereby eliminating the pre-welding process.

[0044] The above specific examples are used to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core ideas of the present application. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present application, several improvements and modifications can be made to the present application, and these improvements and modifications also fall within the scope of protection of the present application.

Claims

1. A battery cover assembly, characterized in that: The battery cover plate assembly comprises a cover plate, a copper-aluminum composite pole and an insulating member, wherein the copper-aluminum composite pole comprises a pole lug welding section, an output section and a connecting section; a plurality of protrusions for welding with the pole lug are provided on an end surface of the pole lug welding section close to the pole lug, and the plurality of protrusions are spaced from each other, the output section is used to connect with a conductive member other than a battery, the connecting section connects an end of the pole lug welding section away from the pole lug and the output section, a through hole is provided on the cover plate, the connecting section at least partially passes through the through hole, the insulating member is arranged on the outer periphery of the pole and passes through the through hole, so that the pole is insulated from the cover plate; the copper-aluminum composite pole comprises a copper layer and an aluminum layer, the copper layer is on the side close to the pole lug, and the aluminum layer is on the side away from the pole lug, the copper layer comprises a copper layer body and the protrusions, the thickness of the copper layer body is a, the thickness of the aluminum layer is b, the distance between the orthographic projections of adjacent protrusions on the end surface of the pole lug welding section close to the pole lug is L, 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 section includes a first connecting section and a second connecting section, the first connecting section connects the pole tab welding section, the second connecting section connects the first connecting section and the output section, the first connecting section at least partially passes through the through hole, the interface between the copper layer and the aluminum layer is a copper-aluminum composite interface, and the copper-aluminum composite interface is located at the interface between the first connecting section and the pole tab welding section, 1mm≤L≤5mm.

7. The battery cover assembly according to claim 1, characterized in that: The connecting section includes a first connecting section and a second connecting section, the first connecting section connects the pole ear welding section, the second connecting section connects the first connecting section and the output section, the first connecting section at least partially passes through the through hole, the interface between the copper layer and the aluminum layer is a copper-aluminum composite interface, and the copper-aluminum composite interface is located at the interface between the first connecting section and the second connecting section, 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, and 0.5mm≤D≤3mm.

9. The battery cover assembly according to claim 1, characterized in that: The thickness of the insulating member between an end surface of the pole lug welding section away from the pole lug and a side surface of the cover plate close to the pole lug is X, and 0.3 mm≤X≤5 mm.

10. The battery cover assembly according to claim 1, characterized in that: The pole is formed by cold heading.

11. The battery cover assembly according to claim 1, characterized in that: The battery cover plate assembly includes an output member, and the connecting section includes a first connecting section and a second connecting section, the first connecting section is connected to the pole ear welding section, the second connecting section is connected to the first connecting section and the output section, the first connecting section at least partially passes through the through hole, and a first step surface and a second step surface are respectively formed between the first connecting section and the second connecting section and between the second connecting section and the output section, the first step surface, the second step surface and the outer peripheral surface of the second connecting section are surrounded to form a rivet groove, and the output member is riveted to the pole through the rivet groove.

12. A battery, characterized in that The battery cover plate assembly comprises the battery cell and a shell, wherein the battery cell comprises a battery cell body and a pole ear extending from the battery cell body, the shell is connected to a side of the cover plate close to the pole ear, and together with the cover plate, forms a accommodating cavity, and the battery cell is located in the accommodating cavity.

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