Battery top cover and square battery

Abstract

The battery top cover comprises a cover plate assembly and a negative terminal arranged on the cover plate assembly, the cover plate assembly is provided with an outer side face and an inner side face which are opposite, the negative terminal comprises a first terminal and a second terminal, the first terminal is arranged on the outer side face, one end of the second terminal is connected with the first terminal, and the other end of the second terminal is connected with the inner side face. Part of the second terminals abut against the outer side face, and the other ends of the second terminals penetrate through the cover plate assembly and extend to one side of the inner side face. The cover plate assembly can support the second terminal, pulling force is directly transmitted to the cover plate assembly from the second terminal instead of being transmitted to the first terminal from the second terminal, so that the negative terminal is prevented from being broken due to stress, and the purpose of improving the bonding strength between the first terminal and the second terminal is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of battery manufacturing, in particular to a battery top cover and a square battery. Background Art

[0002] The square battery is a common lithium battery, and its overall shape is a rectangular structure, so it is called a square battery. The existing square battery mainly includes a shell, a core pack and a top cover assembly. The core pack is installed inside the shell and is filled with electrolyte. The top cover assembly is installed at the open end of the shell so that the core pack and the electrolyte are sealed between the shell and the top cover assembly. The top cover assembly is provided with a positive terminal and a negative terminal for connecting to an external circuit. To ensure the performance of the positive and negative terminals, the positive terminal is usually made of aluminum material, and the negative terminal is usually made of copper-aluminum composite material. The negative terminal includes an aluminum part for connecting to an external circuit and a copper part for connecting to the core pack. The copper part and the aluminum part in the negative terminal are formed into one by friction welding or cold heading.

[0003] The existing technology has the following deficiencies: when the negative terminal is used on a thin low-voltage battery or blade battery, the width of the negative terminal is also small, which is limited by the processing range of the cold heading equipment, making the processing of the negative terminal difficult, and the bonding strength of the bonding surface between the aluminum part and the copper part is weak, which affects the service life of the negative terminal. In addition, the bonding strength of the bonding surface between the copper part and the aluminum part is weakened due to long-term immersion in electrolyte. At the same time, during the use of the square battery, since the copper part and the aluminum part are connected to the external circuit and the core package respectively, their bonding surfaces are pulled in opposite directions, which leads to the risk of breakage of the negative terminal. Utility Model Content

[0004] The utility model aims to provide a battery top cover and a square battery, which have simple processing technology, small processing range restrictions, high bonding strength between copper terminals and aluminum terminals, and long service life.

[0005] To achieve this purpose, the utility model adopts the following technical solutions:

[0006] A battery top cover is provided, comprising a cover assembly and a negative terminal arranged on the cover assembly, the cover assembly having opposite outer side surfaces and inner side surfaces, and characterized in that the negative terminal comprises a first terminal and a second terminal made of different materials, the first terminal being arranged on the outer side surface, one end of the second terminal being connected to the first terminal, and a portion of the second terminal being abutted against the outer side surface, and the other end of the second terminal passing through the cover assembly and extending to one side of the inner side surface.

[0007] Furthermore, the second terminal includes a mounting portion and a connecting portion disposed on the mounting portion, the connecting portion is located in the middle of the mounting portion, the periphery of the mounting portion abuts against the outer surface, and the connecting portion passes through the cover plate assembly.

[0008] Furthermore, a width dimension of the abutment surface between the mounting portion and the cover plate assembly is greater than or equal to 2 mm.

[0009] Furthermore, a mounting groove is provided on the first terminal, the mounting portion is plugged into the mounting groove, and the mounting portion is flush with a notch of the mounting groove.

[0010] Furthermore, along the width direction of the mounting portion, the mounting groove passes through the first terminal.

[0011] Furthermore, the depth of the mounting groove is 0.5-1.5 mm.

[0012] Furthermore, a mounting hole is provided through the first terminal, the mounting portion is plugged into the mounting hole, and two ends of the mounting portion in the axial direction are respectively flush with two ends of the first terminal.

[0013] Furthermore, the first terminal is an aluminum terminal, and the second terminal is a copper terminal.

[0014] Furthermore, the joint between the first terminal and the second terminal is welded to form a weld mark, and the weld mark is located on one side of the outer side surface of the cover plate assembly.

[0015] Furthermore, the welding mark is recessed on a side of the first terminal facing the cover plate assembly; or, an avoidance groove for avoiding the welding mark is recessed on the outer side surface.

[0016] Furthermore, it also includes a positive electrode collector and a negative electrode collector arranged on one side of the inner side of the cover plate assembly, and a positive terminal arranged on the cover plate assembly, the positive electrode collector and the negative electrode collector are respectively used to connect to the positive electrode ear and the negative electrode ear of the core package, the positive terminal is connected to the positive electrode collector, and the end of the second terminal facing away from the first terminal is connected to the negative electrode collector.

[0017] Furthermore, the cover plate assembly includes a top cover sheet, an upper plastic bracket, a lower plastic bracket and a sealing ring, the upper plastic bracket and the lower plastic bracket are respectively arranged on two opposite sides of the top cover sheet, the upper plastic bracket is provided with a receiving groove, the first terminal is inserted into the receiving groove, and the sealing ring is sleeved on the periphery of the second terminal.

[0018] A square battery is also provided, comprising a shell, a core pack and a battery top cover, wherein the shell is a hollow structure with one end open, the core pack is installed in the shell, the battery top cover is installed on the shell and is used to seal the opening of the shell, the positive terminal of the battery top cover is electrically connected to the positive pole ear of the core pack, and the negative terminal of the battery top cover is electrically connected to the negative pole ear of the core pack.

[0019] The beneficial effects of the utility model are as follows: by setting the second terminal to be connected with the first terminal, and making the end of the second terminal close to the first terminal abut against the outer surface of the cover assembly. During the use of the square battery, the second terminal will be subjected to the downward pulling force applied by the core package. Since part of the second terminal abuts against the outer surface, the cover assembly can support the second terminal. The pulling force is directly transmitted from the second terminal to the cover assembly, rather than from the second terminal to the first terminal, thereby avoiding the negative terminal from being broken by the force, so as to achieve the purpose of improving the bonding strength between the first terminal and the second terminal. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of a battery top cover according to an embodiment of the utility model.

[0021] Figure 2 This is an exploded view of the battery top cover according to an embodiment of the present utility model.

[0022] Figure 3 It is a partial cross-sectional view of a battery top cover according to an embodiment of the utility model.

[0023] Figure 4 It is a schematic diagram of the installation of the negative terminal and the upper plastic bracket according to an embodiment of the utility model.

[0024] Figure 5 FIG. 1 is a schematic diagram of the installation of the negative terminal and the upper plastic bracket according to another embodiment of the utility model.

[0025] Figure 6 This is an exploded view of the negative terminal of one embodiment of the present invention.

[0026] Figure 7 FIG. 1 is a schematic diagram of a negative terminal according to another embodiment of the present invention.

[0027] Figure 8 This is an exploded view of a negative terminal according to another embodiment of the present invention.

[0028] Fig. 9 It is a schematic diagram of a square battery according to an embodiment of the utility model.

[0029] In the figure:

[0030] 1. Positive terminal; 2. Negative terminal; 20. Welding mark; 21. Aluminum terminal; 211. Mounting groove; 212. Mounting hole; 213. First side; 214. Bevel; 22. Copper terminal; 221. Mounting part; 222. Connecting part; 3. Cover plate assembly; 30. Outer side; 31. Top cover piece; 32. Upper plastic bracket; 321. Receiving groove; 322. Avoidance groove; 33. Lower plastic bracket; 34. Sealing ring; 35. Injection hole; 36. Explosion-proof valve; 4. Positive current collector; 5. Negative current collector; 51. First connecting plate; 52. Second connecting plate; 53. Connecting hole; 6. Shell. DETAILED DESCRIPTION

[0031] In order to make the technical problems solved by the present invention, the technical solutions adopted and the technical effects achieved more clearly, the technical solutions of the present invention are further explained below with reference to the accompanying drawings and through specific implementation methods.

[0032] like Figure 1 As shown, a battery top cover provided by the utility model is applied to a square battery. The overall shape of the battery top cover is similar to a cuboid, the length direction of the battery top cover is the X direction shown in the figure, the width direction is the Y direction shown in the figure, and the thickness direction is the Z direction shown in the figure. The battery top cover includes a positive terminal 1, a negative terminal 2, a cover assembly 3, a positive electrode collector 4 and a negative electrode collector 5. Among them, the positive terminal 1 and the negative terminal 2 are both used to connect to an external circuit to realize the current input or output of the square battery. Along the length direction of the battery top cover, the positive terminal 1 and the negative terminal 2 are arranged on the cover assembly 3 at intervals. Along the thickness direction of the battery top cover, the two opposite sides on the cover assembly 3 are the outer side 30 and the inner side, respectively, the outer side 30 faces the outside of the square battery, and the inner side faces the inside of the square battery. The positive terminal 1 is installed on the cover assembly 3, and the positive electrode collector 4 is located on the inner side of the cover assembly 3, that is, the positive electrode collector 4 is located inside the square battery. The positive terminal 1 is connected to the positive electrode collector 4, and the positive electrode ear on the core package is welded and fixed to the positive electrode collector 4 to achieve the circuit connection between the positive terminal 1 and the positive electrode of the core package. The negative terminal 2 is installed on the cover assembly 3, and the negative electrode collector 5 is located on one side of the inner side of the cover assembly 3, that is, the negative electrode collector 5 is located inside the square battery. The negative terminal 2 is connected to the negative electrode collector 5, and the negative electrode ear on the core package is welded and fixed to the negative electrode collector 5 to achieve the circuit connection between the negative terminal 2 and the negative electrode of the core package.

[0033] Reference Figure 2 and Figure 3As shown, the cover assembly 3 includes a top cover sheet 31, an upper plastic bracket 32, a lower plastic bracket 33 and a sealing ring 34. The upper plastic bracket 32 ​​is used to install the positive terminal 1 and the negative terminal 2 to play an insulating and protective role. There are two upper plastic brackets 32, and the two upper plastic brackets 32 are arranged at intervals along the length direction (X direction shown in the figure) of the cover assembly 3. The upper plastic bracket 32 ​​is arranged on the side of the top cover sheet 31 facing the outside of the square battery, and the positive terminal 1 and the negative terminal 2 are respectively installed on the two upper plastic brackets 32. The lower plastic bracket 33 is arranged on the side of the top cover sheet 31 facing the inside of the square battery, which plays an insulating and protective role for conductive elements such as positive and negative terminals and positive and negative collectors. Both the positive terminal 1 and the negative terminal 2 need to pass through the top cover sheet 31, and the positive terminal 1 and the negative terminal 2 are both sleeved with a sealing ring 34, which is used to play an insulating and sealing role between the positive and negative terminals and the top cover sheet 31.

[0034] It should be noted that the upper plastic bracket 32 ​​cannot cover the side of the entire top cover sheet 31 facing the outside of the square battery, so the side of the upper plastic bracket 32 ​​facing the outside of the square battery and the side of the top cover sheet 31 facing the outside of the square battery and not covered by the upper plastic bracket 32 ​​together form the outer side 30 of the cover assembly 3. The lower plastic bracket 33 can cover the entire top cover sheet 31, and the side of the lower plastic bracket 33 facing away from the top cover sheet 31 forms the inner side of the cover assembly 3.

[0035] Specifically, the upper plastic support 32 is provided with a receiving groove 321, and the shape and size of the receiving groove 321 are matched with the positive terminal 1 or the negative terminal 2. One end of the positive terminal 1 is inserted into the receiving groove 321 of the corresponding upper plastic support 32, and the other end passes through the cover assembly 3 and is connected to the positive electrode collector 4. One end of the negative terminal 2 is inserted into the receiving groove 321 of the corresponding upper plastic support 32, and the other end passes through the cover assembly 3 and is connected to the negative electrode collector 5.

[0036] Specifically, the negative terminal 2 includes a first terminal and a second terminal of different materials. Among them, the first terminal is an aluminum terminal 21, and the second terminal is a copper terminal 22. The aluminum terminal 21 is arranged in the receiving groove 321 of the upper plastic bracket 32. It can also be understood that the notch of the receiving groove 321 of the upper plastic bracket 32 ​​faces the outside of the square battery, and the aluminum terminal 21 is installed in the receiving groove 321, that is, the aluminum terminal 21 is arranged on the outer side 30 of the cover plate assembly 3. One end of the copper terminal 22 is inserted into the aluminum terminal 21 and is welded and fixed to the aluminum terminal 21 by laser welding. The end of the copper terminal 22 away from the aluminum terminal 21 passes through the cover plate assembly 3 and extends to one side of the inner side of the cover plate assembly 3. That is, one end of the copper terminal 22 extends to the inside of the square battery to achieve connection with the negative electrode collector 5. Since the copper terminal 22 needs to pass through the cover plate assembly 3, the upper plastic bracket 32, the lower plastic bracket 33 and the top cover sheet 31 are all penetrated with a through hole for the copper terminal 22 to pass through. The through hole on the upper plastic bracket 32 ​​is opened at the bottom of the receiving groove 321. The cross section of the end of the copper terminal 22 inserted into the aluminum terminal 21 is larger than the size of the through hole on the upper plastic bracket 32, so that the end of the copper terminal 22 inserted into the aluminum terminal 21 can be against the bottom of the receiving groove 321, that is, part of the copper terminal 22 is against the outer side 30 of the cover assembly 3. It can be understood that the aluminum terminal 21 and the copper terminal 22 are welded and fixed by laser welding. Compared with cold heading, its processing technology is simpler and will not be limited by the processing size, and at the same time, the bonding strength between the aluminum terminal 21 and the copper terminal 22 is higher. Since the end of the copper terminal 22 close to the outside of the square battery is against the outer side 30 of the cover assembly 3, the tension of the core package on the copper terminal 22 is partially distributed to the cover assembly 3, thereby reducing the pulling force on the joint surface of the aluminum terminal 21 and the copper terminal 22, which can avoid the fracture of the negative terminal 2 at the joint surface position and improve the service life of the negative terminal 2.

[0037] Reference Figure 3 and Figure 6As shown, the aluminum terminal 21 is a rectangular parallelepiped structure, and along the thickness direction of the aluminum terminal 21 (Z direction in the figure), the two opposite sides of the aluminum terminal 21 are respectively a first side 213 and a second side. The first side 213 of the aluminum terminal 21 abuts against the bottom of the accommodating groove 321, and the second side of the aluminum terminal 21 is used to connect with the external circuit. A mounting groove 211 is provided on the first side 213 of the aluminum terminal 21, and the cross section of the mounting groove 211 is rectangular, that is, the bottom of the mounting groove 211 is rectangular. Along the width direction of the aluminum terminal 21 (Y direction in the figure), the mounting groove 211 passes through the aluminum terminal 21, that is, the width of the mounting groove 211 is equal to the width of the aluminum terminal 21. Correspondingly, the copper terminal 22 includes a mounting portion 221 and a connecting portion 222 arranged on the mounting portion 221. The shape and size of the mounting portion 221 are arranged in coordination with the mounting groove 211, that is, the mounting portion 221 is a rectangular parallelepiped structure. The mounting portion 221 is plugged into the mounting groove 211, and the mounting portion 221 is flush with the notch of the mounting groove 211. When the negative terminal 2 is mounted on the upper plastic bracket 32, the first side 213 of the aluminum terminal 21 abuts against the bottom of the accommodating groove 321, and the peripheral area of ​​the mounting portion 221 facing the side of the connecting portion 222 also abuts against the bottom of the accommodating groove 321. It can also be understood that the periphery of the aluminum terminal 21 and the mounting portion 221 are both against the outer side 30 of the cover assembly 3. It can be understood that by making the mounting portion 221 flush with the notch of the mounting groove 211, the mounting portion 221 is flush with the first side 213 of the aluminum terminal 21, so that the aluminum terminal 21 and the mounting portion 221 can both abut against the bottom of the mounting groove 211. And, since the overall width of the battery top cover is small, the width of the negative terminal 2 is also small. Therefore, when welding the copper terminal 22 and the aluminum terminal 21, it is sufficient to weld only the two ends of the length direction (X direction in the figure) of the mounting portion 221 of the copper terminal 22, and it is not necessary to weld the two ends of the width direction of the mounting portion 221 to the aluminum terminal 21. By connecting the mounting groove 211 of the aluminum terminal 21 with the outer wall of the aluminum terminal 21, it is helpful to reduce the processing difficulty of the mounting groove 211 while meeting the welding process requirements. Of course, in other embodiments, the cross-sectional shape of the mounting groove 211 can also be circular, square, triangular, elliptical, prismatic, polygonal (such as hexagonal), etc.

[0038] Specifically, the width dimension of the abutment surface between the mounting portion 221 and the cover plate assembly 3 is B, and B≥2mm. Since the periphery of the mounting portion 221 abuts against the upper plastic bracket 32, the abutment surface between the mounting portion 221 and the cover plate assembly 3 is the abutment surface between the mounting portion 221 and the upper plastic bracket 32. In this embodiment, a through hole for penetrating the connecting portion 222 is provided on the upper plastic bracket 32. The width of the abutment surface refers to the distance from the edge of the mounting portion 221 to the edge of the through hole along the radial direction of the through hole of the upper plastic bracket 32. In a specific implementation, the width dimension B of the abutment surface can be selected as 2mm, 2.5mm, 3mm, 3.5mm, 4mm, etc. It should be noted that the specific selection of the width dimension B of the abutment surface can be comprehensively considered according to factors such as the material strength of the mounting portion 221 itself and the thickness of the mounting portion 221, so as to ensure that the mounting portion 221 can be firmly supported on the cover plate assembly 3.

[0039] Specifically, the connecting portion 222 is a cylindrical structure, the connecting portion 222 is located in the middle of the mounting portion 221, one end of the connecting portion 222 is connected to the mounting portion 221, and the other end passes through the cover assembly 3 and is connected to the negative electrode collector 5, that is, the end of the connecting portion 222 that is away from the mounting portion 221 extends to one side of the inner side of the cover assembly 3. If the connecting portion 222 is set as a cylindrical structure, the through hole opened on the corresponding cover assembly 3 is also a circular hole for easy processing. Of course, in other embodiments, the connecting portion 222 can also be set to other shapes. For example, the cross-section of the connecting portion 222 can also be a triangle, square, rectangle, hexagon, etc. Since the connecting portion 222 is passed through the cover assembly 3, correspondingly, the sealing ring 34 is sleeved on the periphery of the connecting portion 222 of the copper terminal 22.

[0040] Specifically, the depth dimension of the mounting groove 211 of the aluminum terminal 21 is equal to the thickness dimension of the mounting portion 221 of the copper terminal 22. The depth dimension of the mounting groove 211 is 0.5-1.5mm, and correspondingly, the thickness dimension of the mounting portion 221 is also 0.5-1.5mm. Since the mounting portion 221 abuts against the outer side surface 30 of the cover plate assembly 3, the core package inside the square battery will apply tension to the mounting portion 221 through the connecting portion 222. Therefore, the thickness dimension of the mounting portion 221 will affect its ability to withstand tension. In practical applications, the thickness dimension of the mounting portion 221 can be reasonably selected according to the specific structure of the square battery and the stress condition of the negative terminal 2. In this embodiment, the thickness dimension of the mounting portion 221 and the depth dimension of the mounting groove 211 include but are not limited to 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm and 1.5mm.

[0041] In another embodiment, referring to Figure 7 As shown (partial number combined Figure 6As shown in the figure, the aluminum terminal 21 is provided with a mounting groove 211, and the groove wall of the mounting groove 211 is not connected to the outer wall of the aluminum terminal 21. The mounting portion 221 is a rectangular parallelepiped structure, and the mounting portion 221 is inserted into the mounting groove 211. This structure enables the four edges of the periphery of the mounting portion 221 to be welded and fixed to the aluminum terminal 21, which is conducive to increasing the welding length and improving the bonding strength between the aluminum terminal 21 and the copper terminal 22.

[0042] In yet another embodiment, referring to Figure 8 As shown, the aluminum terminal 21 is provided with a mounting hole 212, which is a round hole for easy processing. The copper terminal 22 includes a mounting portion 221 and a connecting portion 222 provided on the mounting portion 221. The mounting portion 221 and the connecting portion 222 are both cylindrical structures, and the diameter of the mounting portion 221 is greater than the diameter of the connecting portion 222. The mounting portion 221 is inserted into the mounting hole 212, and the two ends of the mounting portion 221 in the axial direction are respectively flush with the two end faces in the thickness direction of the aluminum terminal 21. This structure can realize that the two opposite end faces of the aluminum terminal 21 can be welded with the mounting portion 221, so as to improve the bonding strength between the copper terminal 22 and the aluminum terminal 21.

[0043] Specifically, refer to Figure 3 and Figure 4 As shown (partial number combined Figure 6 As shown in the figure, the joint of the aluminum terminal 21 and the copper terminal 22 is welded to form a weld mark 20, and the weld mark 20 is located on one side of the outer side 30 of the cover plate assembly 3. After the mounting portion 221 of the copper terminal 22 is plugged into the mounting groove 211 of the aluminum terminal 21, the side of the mounting portion 221 facing the connecting portion 222 is flush with the first side 213 of the aluminum terminal 21. Laser welding is performed on the joint of the side of the mounting portion 221 facing the connecting portion 222 and the first side 213 to form a weld mark 20. Since the periphery of the mounting portion 221 abuts against the outer side 30 of the cover plate assembly 3, the weld mark 20 is also located on one side of the outer side 30 of the cover plate assembly 3. This structure can keep the weld mark 20 away from the interior of the square battery. Under the isolation effect of the cover plate assembly 3, the weld mark 20 can be prevented from being immersed in the electrolyte, thereby preventing the weakening of the bonding strength between the aluminum terminal 21 and the copper terminal 22 due to the long-term immersion of the weld mark 20 in the electrolyte.

[0044] In order to ensure that the first side surface 213 of the aluminum terminal 21 and the mounting portion 221 can be evenly pressed against the bottom of the receiving groove 321, the weld mark 20 is recessed in the side surface of the aluminum terminal 21 facing the cover plate assembly 3, that is, the weld mark 20 is recessed in the first side surface 213 of the aluminum terminal 21. In practical applications, a groove 214 can be processed at the groove position of the mounting groove 211 of the aluminum terminal 21, and a groove 214 can be processed around the mounting portion 221, so that the weld mark 20 formed after welding can be recessed in the first side surface 213 of the aluminum terminal 21, avoiding direct contact between the weld mark 20 and the bottom of the receiving groove 321.

[0045] In another embodiment, referring to Figure 5 As shown, the joint of the aluminum terminal 21 and the copper terminal 22 is welded to form a weld mark 20, and the weld mark 20 is located on one side of the outer side surface 30 of the cover plate assembly 3. The bottom of the accommodating groove 321 is concavely provided with an avoidance groove 322 (that is, the avoidance groove 322 is provided on the outer side surface 30), and the avoidance groove 322 is directly opposite to the weld mark 20. The avoidance groove 322 is provided to avoid the portion of the weld mark 20 protruding from the first side surface 213 of the aluminum terminal 21, so as to ensure that the first side surface 213 of the aluminum terminal 21 and the mounting portion 221 can be flatly abutted against the bottom of the accommodating groove 321 (the outer side surface 30).

[0046] Specifically, refer to Figure 2 and Figure 3 As shown (partial number combined Figure 6 As shown in the figure, the negative electrode current collector 5 includes a first connecting plate 51 and a second connecting plate 52, the first connecting plate 51 is parallel to the cover plate assembly 3, one end of the second connecting plate 52 is connected to the first connecting plate 51, and the other end extends in a direction away from the cover plate assembly 3. The length of the second connecting plate 52 extends along the thickness direction of the battery top cover, and the negative electrode ear on the core package is welded to the second connecting plate 52. The first connecting plate 51 is installed on the inner side of the cover plate assembly 3, and a connecting hole 53 is provided through the first connecting plate 51. One end of the connecting portion 222 away from the mounting portion 221 is inserted into the connecting hole 53, and the mounting portion 221 is welded and fixed to the first connecting plate 51 of the negative electrode current collector 5 by laser welding. The connecting hole 53 is a countersunk hole, and one end of the large hole of the connecting hole 53 faces the inside of the square battery, and one end of the small hole of the connecting hole 53 faces the outside of the square battery. The connecting portion 222 is inserted into the small hole of the connecting hole 53 , so that the large hole of the connecting hole 53 can be used to accommodate the weld mark 20 formed by welding between the negative electrode collector 5 and the connecting portion 222 , so as to ensure the surface flatness of the first connecting plate 51 .

[0047] Specifically, the cover plate assembly 3 is also provided with a liquid injection hole 35 and an explosion-proof valve 36. The liquid injection hole 35 is used to inject electrolyte into the interior of the square battery. The explosion-proof valve 36 is used to provide pressure relief protection when the square battery has thermal runaway.

[0048] Specifically, the positive terminal 1 has the same structure as the negative terminal 2, and the structure of the positive terminal 1 is not described in detail herein. The positive terminal 1 is made of aluminum, and the positive terminal 1 can be integrally formed by stamping, casting, or the like.

[0049] like Fig. 9As shown, a square battery is also provided, including a shell 6, a core pack and a battery top cover. The shape of the entire square battery is a rectangular parallelepiped, the length direction of the square battery is the X direction shown in the figure, the width direction is the Y direction shown in the figure, and the height direction is the Z direction shown in the figure. The shell 6 is a hollow structure with one end open, and the core pack is installed inside the shell 6. The core pack is stacked or wound in a certain order by a positive electrode sheet, a negative electrode sheet, and a diaphragm. The battery top cover is installed at the open end of the shell 6, and the battery top cover is used to block the opening of the shell 6. The inside of the shell 6 is also filled with electrolyte. The outer side surface 30 of the cover assembly 3 is away from the shell 6, and the inner side surface of the cover assembly 3 faces the shell 6. The positive current collector 4 and the negative current collector 5 are located inside the shell 6, and the positive current collector 4 and the negative current collector 5 are respectively located at both ends of the length direction of the square battery. The positive electrode ear of the core package is welded and fixed on the positive electrode collector 4, and the negative electrode ear of the core package is welded and fixed on the negative electrode collector 5, so as to realize the electrical connection between the positive terminal 1 on the battery top cover and the positive electrode ear of the core package, and the electrical connection between the negative terminal 2 on the battery top cover and the negative electrode ear of the core package.

[0050] The significant effect of this embodiment is that the second terminal is connected to the first terminal, and the end of the second terminal close to the first terminal is against the outer side surface 30 of the cover assembly 3. During the use of the square battery, the second terminal will be subjected to the downward pulling force applied by the core package. Since part of the second terminal is against the outer side surface 30, the cover assembly 3 can support the second terminal. The pulling force is directly transmitted from the second terminal to the cover assembly 3, rather than from the second terminal to the first terminal, thereby avoiding the negative terminal 2 from being broken by force, so as to achieve the purpose of improving the bonding strength between the first terminal and the second terminal. After the second terminal is plugged into the first terminal, it is fixed by welding at the junction of the two. Compared with the corresponding cold heading processing method, it has the characteristics of simple processing technology and no processing size restriction. At the same time, since part of the second terminal is against the outer side surface 30, the welding position of the second terminal and the first terminal can be located on one side of the outer side surface 30 of the cover assembly 3, so that the weld between the two is away from the inside of the square battery, avoiding the weld from being immersed in the electrolyte for a long time and causing a fracture accident, and improving the service life of the negative terminal 2.

[0051] The above contents are only preferred embodiments of the present invention. For ordinary technicians in this field, according to the concept of the present invention, there will be changes in the specific implementation methods and application scopes. The contents of this specification should not be understood as limiting the present invention.

Claims

1. A battery top cover, comprising a cover plate assembly and a negative terminal disposed on the cover plate assembly, wherein the cover plate assembly has an outer side surface and an inner side surface opposite to each other, characterized in that: The negative terminal includes a first terminal and a second terminal made of different materials, the first terminal is arranged on the outer side surface, one end of the second terminal is connected to the first terminal, and a portion of the second terminal is against the outer side surface, and the other end of the second terminal passes through the cover plate assembly and extends to one side of the inner side surface.

2. The battery top cover according to claim 1, characterized in that: The second terminal includes a mounting portion and a connecting portion disposed on the mounting portion, wherein the connecting portion is located in the middle of the mounting portion, the periphery of the mounting portion abuts against the outer surface, and the connecting portion passes through the cover plate assembly.

3. The battery top cover according to claim 2, characterized in that: The width dimension of the abutment surface between the mounting portion and the cover plate assembly is greater than or equal to 2 mm.

4. The battery top cover according to claim 2, characterized in that: The first terminal is provided with a mounting groove, the mounting portion is plugged into the mounting groove, and the mounting portion is flush with a notch of the mounting groove.

5. The battery top cover according to claim 4, characterized in that: The mounting groove passes through the first terminal along a width direction of the mounting portion.

6. The battery top cover according to claim 4, characterized in that: The depth of the mounting groove is 0.5-1.5 mm.

7. The battery top cover according to claim 2, characterized in that: The first terminal is provided with a mounting hole, the mounting portion is plugged into the mounting hole, and two ends of the mounting portion in the axial direction are respectively flush with two ends of the first terminal.

8. The battery top cover according to any one of claims 1 to 7, characterized in that: The first terminal is an aluminum terminal, and the second terminal is a copper terminal.

9. The battery top cover according to any one of claims 1 to 7, characterized in that: The joint between the first terminal and the second terminal is welded to form a weld mark, and the weld mark is located on one side of the outer side surface of the cover plate assembly.

10. The battery top cover according to claim 9, characterized in that: The welding mark is recessed on a side of the first terminal facing the cover assembly; or, an avoidance groove for avoiding the welding mark is recessed on the outer side.

11. The battery top cover according to any one of claims 1 to 7, characterized in that: It also includes a positive electrode collector and a negative electrode collector arranged on one side of the inner side of the cover plate assembly, and a positive terminal arranged on the cover plate assembly, the positive electrode collector and the negative electrode collector are respectively used to connect to the positive electrode ear and the negative electrode ear of the core package, the positive terminal is connected to the positive electrode collector, and the end of the second terminal facing away from the first terminal is connected to the negative electrode collector.

12. The battery top cover according to any one of claims 1 to 7, characterized in that: The cover plate assembly includes a top cover sheet, an upper plastic bracket, a lower plastic bracket and a sealing ring. The upper plastic bracket and the lower plastic bracket are respectively arranged on two opposite sides of the top cover sheet. The upper plastic bracket is provided with a receiving groove. The first terminal is inserted into the receiving groove. The sealing ring is sleeved on the periphery of the second terminal.

13. A square battery, characterized in that: It comprises a shell, a core pack and a battery top cover as claimed in any one of claims 1 to 12, wherein the shell is a hollow structure with one end open, the core pack is installed in the shell, the battery top cover is installed on the shell and is used to seal the opening of the shell, the positive terminal of the battery top cover is electrically connected to the positive pole ear of the core pack, and the negative terminal of the battery top cover is electrically connected to the negative pole ear of the core pack.

Images