Positive current collector and cylindrical battery

Abstract

The application provides a positive electrode current collector plate, which is located between a positive electrode tab and a positive electrode cover plate, and comprises a disc body and an electric connection part. The electric connection part is extended and protruded from the disc body towards the positive electrode cover plate. The disc body is in contact with the positive electrode tab, and the electric connection part is in contact with the positive electrode cover plate. The application greatly reduces the internal resistance of the positive electrode current collector plate, thereby improving the conductivity of the battery. Meanwhile, the electric connection part on the positive electrode current collector plate does not need to be bent in a "Z" shape, and is not prone to cracks, so that the assembly efficiency is high and the application is suitable for industrial production requirements. The application also provides a cylindrical battery.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a positive current collector and a cylindrical battery. Background Technology

[0002] With the development of electronic technology, lithium-ion batteries have become widely used due to their advantages such as high specific power, long cycle life, good safety performance, and no pollution. To increase the single-cell capacity and reduce manufacturing costs, the diameter of cylindrical batteries has gradually increased. To meet the charging, discharging, and heat dissipation requirements of large-diameter, high-capacity cylindrical batteries, the core of the cylindrical battery adopts a full-tab design, and positive and negative current collectors connect the core's positive and negative tabs to the battery's positive and negative terminals. Typically, the positive current collector connector is bent into a "Z" shape to connect the core's positive tab to the battery's positive terminal. This method makes the bend in the positive current collector connector prone to cracking, and the current path from the battery's positive terminal to the internal core's positive tab is relatively long, resulting in a high internal resistance of the positive current collector and thus generating more heat during charging and discharging. Summary of the Invention

[0003] The purpose of this application is to provide a positive current collector and a cylindrical battery, which aims to overcome the shortcomings of the above-mentioned prior art. By directly connecting the disk body and the positive cover plate through the electrical connection part, the internal resistance of the positive current collector is greatly reduced, thereby improving the conductivity of the battery. In addition, the electrical connection parts on the positive current collector do not need to be bent in a "Z" shape, which makes it less prone to cracking, and the assembly efficiency is high, which is suitable for the needs of industrial production.

[0004] One embodiment of this application provides a positive current collector for connecting the positive electrode tab and the positive electrode cover of a battery. The positive current collector is located between the positive electrode tab and the positive electrode cover. The positive current collector includes a plate body and an electrical connection portion. The electrical connection portion extends and protrudes from the plate body toward the positive electrode cover. The plate body contacts the positive electrode tab, and the electrical connection portion contacts the positive electrode cover. In this application, the positive electrode cover serves as the positive electrode of the battery.

[0005] In one possible implementation, a through hole is provided at the center of the disk body, and the electrical connection portion extends and protrudes from the outer edge of the through hole toward the positive electrode cover plate.

[0006] In one possible implementation, the electrical connection portion is a planar sheet structure, the positive electrode cover plate has a central hole, and the electrical connection portion passes through the central hole and then contacts the top surface of the positive electrode cover plate by bending.

[0007] In one possible implementation, the electrical connection portion has a circular cross-section, the positive electrode cover plate has a central hole, the electrical connection portion is inserted into and extends out of the central hole, and the outer wall of the electrical connection portion contacts the side wall of the central hole.

[0008] In one possible implementation, the electrical connection portion is a hollow frustum-shaped structure with a gradually decreasing diameter along the direction close to the positive electrode cover plate, and the angle between the outer wall of the electrical connection portion and the vertical direction is 0 to 60°.

[0009] In one feasible embodiment, the electrical connection extends from the positive electrode cover by a height of 0–2 mm, and the minimum cross-sectional area of ​​the electrical connection is (in mm²). 2 The value of ) is 1 / 8 to 1, or 1 / 5 to 1, of the value of 1C current (unit is A).

[0010] In one feasible embodiment, the welding area (in mm) of the electrical connection portion in contact with the positive electrode cover plate 2 The value of ) is 1 / 8 to 1, or 1 / 5 to 1, of the value of 1C current (in A); the contact area (in mm) at the connection between the electrical connection part and the disk body 2 The value of ) is 1 / 8 to 1; or 1 / 5 to 1 of the value of 1C current (unit is A).

[0011] Another embodiment of this application provides a cylindrical battery, including a core, a casing, and a positive electrode cover plate. The cylindrical battery further includes the positive electrode current collector as described above. The top of the casing has an opening, and the positive electrode cover plate is fixed at the opening. The core is located inside the casing, and the top of the core has a positive electrode tab. The positive electrode current collector plate is located between the positive electrode tab and the positive electrode cover plate. The plate body is in contact with the positive electrode tab, and the electrical connection portion is in contact with the positive electrode cover plate.

[0012] In one possible embodiment, the cylindrical battery further includes a negative electrode current collector, a negative electrode tab is provided at the bottom of the core, the negative electrode current collector is located inside the housing, and both sides of the negative electrode current collector are in contact with the negative electrode tab and the inner wall of the housing, respectively.

[0013] In one possible embodiment, the cylindrical battery further includes an insulating sealing ring, an insulating gasket, and an explosion-proof sheet. The insulating sealing ring is arranged around the outer edge of the positive electrode cover and is located between the positive electrode cover and the inner wall of the housing. The insulating gasket is disposed on the top surface of the positive electrode current collector and is located between the positive electrode current collector and the inner wall of the housing. The explosion-proof sheet is sealed to the top surface of the positive electrode cover.

[0014] The positive current collector provided in this application has an electrical connection that directly connects the collector body and the positive electrode cover plate. The collector body is in direct contact with the positive electrode tab, thereby shortening the current path from the positive electrode cover plate to the positive electrode tab, significantly reducing the internal resistance of the positive current collector, improving the battery conductivity, and reducing the heat generated by the positive current collector. Simultaneously, the electrical connectors on this positive current collector do not require "Z"-shaped bending, reducing the likelihood of cracking, and are easy to weld and fix to the positive electrode cover plate, resulting in high assembly efficiency and suitability for industrial production needs. Attached Figure Description

[0015] Figure 1 This is a three-dimensional structural diagram of the positive current collector in the first embodiment of this application.

[0016] Figure 2 for Figure 1 The main view.

[0017] Figure 3 This is a cross-sectional view of the cylindrical battery in the first embodiment of this application.

[0018] Figure 4 This is a three-dimensional structural diagram of the positive current collector in the second embodiment of this application.

[0019] Figure 5 for Figure 4 The main view.

[0020] Figure 6 This is a cross-sectional view of the cylindrical battery in the second embodiment of this application. Detailed Implementation

[0021] The specific embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this application, but are not intended to limit the scope of this application.

[0022] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0023] The directional terms such as "upper," "lower," "left," "right," "front," "back," "top," and "bottom" (if present) used in the specification and claims of this application are defined according to the position of the structures in the drawings and the relative positions of the structures, and are only for the purpose of clarity and convenience in expressing the technical solution. It should be understood that the use of directional terms should not limit the scope of protection claimed in this application.

[0024] like Figures 1 to 3As shown, the positive current collector 1 provided in the first embodiment of this application is used to connect the positive electrode tab 21 and the positive electrode cover plate 3 of the battery. The positive current collector 1 is located between the positive electrode tab 21 and the positive electrode cover plate 3. The positive current collector 1 includes a plate body 11 and an electrical connection part 12. The electrical connection part 12 extends and protrudes from the plate body 11 toward the positive electrode cover plate 3. The plate body 11 is in contact with the positive electrode tab 21, and the electrical connection part 12 is in contact with the positive electrode cover plate 3.

[0025] like Figure 1 and Figure 2 As shown, in one embodiment, the disk body 11 is a disc-shaped structure with hollows and pits. A through hole 111 is provided in the middle of the disk body 11. The electrical connection part 12 extends and protrudes from the outer edge of the through hole 111 toward the positive electrode cover plate 3, that is, the electrical connection part 12 is located in the center of the disk body 11.

[0026] like Figures 1 to 3 As shown, in one embodiment, the electrical connection part 12 is a planar sheet structure, the positive electrode cover plate 3 is provided with a central hole 31, and the electrical connection part 12 passes through the central hole 31 and then contacts the top surface of the positive electrode cover plate 3 by bending.

[0027] Specifically, in this embodiment, there are two electrical connection portions 12, which are disposed opposite to each other on both sides of the through hole 111. Of course, in other embodiments, there may be one or more electrical connection portions 12. In this embodiment, the electrical connection portion 12 is a rectangular metal sheet. However, the electrical connection portion 12 can also be other quadrilateral (e.g., trapezoidal, parallelogram), triangular, or semi-circular structures, which are not limited here. During assembly, the two electrical connection portions 12 extend out of the central hole 31 on the positive electrode cover plate 3 and bend to both sides, with the bent portions overlapping and contacting the top surface of the positive electrode cover plate 3. The overlapping contact portions are then welded and fixed.

[0028] like Figure 3 As shown, in one embodiment, the electrical connection portion 12 extends out of the positive electrode cover plate 3 by a height of 0-4 mm or 0-2 mm. This extended portion is mainly to facilitate the welding of the electrical connection portion 12 to the positive electrode cover plate 3.

[0029] In another embodiment, the electrical connection portion 12 extends out of the positive electrode cover plate 3 by a height of 0 to 1 mm.

[0030] like Figure 1 and Figure 2 As shown, in one embodiment, the minimum cross-sectional area of ​​the electrical connection portion 12 (in mm) 2 The value of ) is 1 / 8 to 1, or 1 / 5 to 1, of the value of 1C current (unit is A).

[0031] like Figure 3As shown, in one embodiment, the welding area (in mm) of the electrical connection portion 12 in contact with the positive electrode cover plate 3 is... 2 The value of ) is 1 / 8 to 1 of the value of 1C current (in A), and the contact area at the connection between the electrical connection part 12 and the disk body 11 is (in mm). 2 The value of ) is 1 / 8 to 1 of the value of 1C current (unit is A).

[0032] Specifically, when the ampere value of the discharge current is equal to the ampere-hour value of the battery capacity, it is called 1C discharge. Theoretically, 1C discharge can completely deplete the energy of a fully charged battery in one hour. For example, if a battery has a capacity of 3000mAh (i.e., 3Ah), and is discharged with a current of 3A, the battery can be completely discharged in one hour. 3A is the 1C current for this battery. Therefore, the welding area where the electrical connection part 12 contacts the positive electrode cover plate 3 is 3 / 8 to 3mm. 2 The contact area at the connection between the electrical connection part 12 and the disk body 11 is 3 / 8 to 3 mm. 2 .

[0033] As another embodiment, the welding area (in mm) of the electrical connection portion 12 in contact with the positive electrode cover plate 3 is... 2 The value of ) is 1 / 5 to 1 of the value of 1C current (in A), and the contact area at the connection between the electrical connection part 12 and the disk body 11 is (in mm). 2 The value of ) is 1 / 5 to 1 of the value of 1C current (unit is A).

[0034] like Figure 3 As shown, the first embodiment of this application also provides a cylindrical battery, including a core 2, a casing 4, and a positive electrode cover 3. The cylindrical battery also includes the positive electrode current collector 1 described above. The top of the casing 4 is provided with an opening 41, and the positive electrode cover 3 is fixed at the opening 41. The core 2 is located inside the casing 4, and the top of the core 2 is provided with a positive electrode tab 21. The positive electrode current collector 1 is located between the positive electrode tab 21 and the positive electrode cover 3, with the plate body 11 in contact with the positive electrode tab 21 and the electrical connection portion 12 in contact with the positive electrode cover 3.

[0035] like Figure 3 As shown, in one embodiment, the cylindrical battery also includes a negative electrode current collector 5. The bottom of the core 2 is provided with a negative electrode tab 22. The negative electrode current collector 5 is located inside the housing 4, and the two sides of the negative electrode current collector 5 are in contact with the negative electrode tab 22 and the inner wall of the housing 4, respectively.

[0036] like Figure 3 As shown, in one implementation, both the positive electrode tab 21 and the negative electrode tab 22 adopt a full-tab design.

[0037] like Figure 3As shown, in one embodiment, the cylindrical battery further includes an insulating sealing ring 6, an insulating gasket 7, and an explosion-proof sheet 8. The insulating sealing ring 6 is arranged around the outer edge of the positive electrode cover plate 3, and is located between the positive electrode cover plate 3 and the inner wall of the housing 4. The insulating gasket 7 is disposed on the top surface of the positive electrode current collector 1, and is located between the positive electrode current collector 1 and the inner wall of the housing 4. The explosion-proof sheet 8 is sealed to the top surface of the positive electrode cover plate 3.

[0038] Specifically, the casing 4 is made of steel. The positive electrode tab 21 is electrically connected to the positive electrode cover plate 3 via the positive electrode current collector 1, and the negative electrode tab 22 is electrically connected to the casing 4 via the negative electrode current collector 5. During battery assembly, the positive electrode current collector 1 and the casing 4 are separated by an insulating gasket 7, and the positive electrode cover plate 3 and the casing 4 are separated by an insulating sealing ring 6. Then, the insulating sealing ring 6 is compressed by mechanical rolling to seal the positive electrode cover plate 3 and the casing 4. After rolling, the positive electrode current collector 1 and the positive electrode cover plate 3 are welded together, and finally, an explosion-proof sheet 8 is welded for sealing. This cylindrical battery greatly improves the conductivity of the cylindrical battery because the path of current from the positive electrode tab 21 to the positive electrode cover plate 3 is shortened.

[0039] like Figures 4 to 6 As shown, in the positive current collector 1 provided in the second embodiment of this application, the cross-section of the electrical connection part 12 is circular. The positive cover plate 3 is provided with a central hole 31. The electrical connection part 12 is inserted into and extends out of the central hole 31, and the outer wall of the electrical connection part 12 is in contact with the side wall of the central hole 31. During assembly, after the electrical connection part 12 extends out of the central hole 31, the outer wall of the electrical connection part 12 is fixed to the side wall of the central hole 31 by welding.

[0040] like Figures 4 to 6 As shown, the electrical connection part 12 is a hollow frustum-shaped structure with a gradually decreasing diameter along the direction close to the positive electrode cover plate 3. The angle α between the outer wall of the electrical connection part 12 and the vertical direction Y is 0 to 60° (this angle α is also called the draft angle). This frustum-shaped structure allows the electrical connection part 12 to pass smoothly through the central hole 31 on the positive electrode cover plate 3.

[0041] like Figure 6 As shown, in one embodiment, the electrical connection part 12 extends out of the positive electrode cover plate 3 by 0 to 2 mm. This extended part is mainly to facilitate the welding of the electrical connection part 12 and the positive electrode cover plate 3.

[0042] In another embodiment, the electrical connection portion 12 extends out of the positive electrode cover plate 3 by a height of 0 to 1 mm.

[0043] like Figure 6 As shown, in one embodiment, the welding area (in mm) of the electrical connection portion 12 in contact with the positive electrode cover plate 3 is... 2The value of ) is 1 / 8 to 1 of the value of 1C current (in A), and the contact area at the connection between the electrical connection part 12 and the disk body 11 is (in mm). 2 The value of ) is 1 / 8 to 1 of the value of 1C current (unit is A).

[0044] As another embodiment, the welding area (in mm) of the electrical connection portion 12 in contact with the positive electrode cover plate 3 is... 2 The value of ) is 1 / 5 to 1 of the value of 1C current (in A), and the contact area at the connection between the electrical connection part 12 and the disk body 11 is (in mm). 2 The value of ) is 1 / 5 to 1 of the value of 1C current (unit is A).

[0045] like Figure 4 and Figure 5 As shown, in one embodiment, the minimum cross-sectional area of ​​the electrical connection portion 12 (in mm) 2 The value of ) is 1 / 8 to 1, or 1 / 5 to 1, of the value of 1C current (unit is A).

[0046] like Figure 6 As shown, the second embodiment of this application also provides a cylindrical battery that uses the positive current collector 1 described above. The other structures of the cylindrical battery are the same as those in the first embodiment, and will not be described in detail here.

[0047] The positive current collector 1 provided in this embodiment has an electrical connection 12 that directly connects the disk body 11 and the positive electrode cover plate 3. The disk body 11 is in direct contact with the positive electrode tab 21, thereby shortening the current path from the positive electrode cover plate 3 to the positive electrode tab 21, greatly reducing the internal resistance of the positive current collector 1, improving the battery conductivity, and reducing the heat generation of the positive current collector 1. Simultaneously, the electrical connection 12 on the positive current collector 1 does not require a "Z"-shaped bend, making it less prone to cracking, and it is easy to weld and fix to the positive electrode cover plate 3, resulting in high assembly efficiency and suitability for industrial production needs. Therefore, the positive current collector 1 provided in this embodiment solves the problems of high heat generation of the positive current collector, the need for bending of electrical connections during assembly, easy cracking, low assembly efficiency, and poor battery conductivity in traditional cylindrical all-tab batteries.

[0048] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A cylindrical battery, comprising a core (2), a positive electrode cover (3), and a positive electrode current collector (1), wherein a positive electrode tab (21) is provided on the top of the core (2), and the positive electrode current collector (1) is located between the positive electrode tab (21) and the positive electrode cover (3), characterized in that, The positive electrode current collector (1) includes a plate body (11) and an electrical connection part (12). The electrical connection part (12) extends and protrudes from the plate body (11) toward the positive electrode cover plate (3). The plate body (11) is in contact with the positive electrode tab (21). The electrical connection part (12) is a planar sheet structure. The positive electrode cover plate (3) is provided with a central hole (31). The electrical connection part (12) passes through the central hole (31) and then contacts the top surface of the positive electrode cover plate (3) by bending. The bent part of the electrical connection part (12) is welded and fixed to the top surface of the positive electrode cover plate (3).

2. The cylindrical battery as described in claim 1, characterized in that, The disk body (11) has a through hole (111) in the middle position, and the electrical connection part (12) extends outward from the outer edge of the through hole (111) toward the positive electrode cover plate (3).

3. The cylindrical battery as described in claim 1, characterized in that, The upper surface of the disc (11) is provided with a pit, and the lower surface of the disc (11) at the pit protrudes downward and contacts the positive electrode tab (21).

4. The cylindrical battery as described in claim 1, characterized in that, The electrical connection part (12) extends out of the positive electrode cover plate (3) by a height of 0~2mm, and the minimum cross-sectional area (in mm²) of the electrical connection part (12) is 1 / 8~1 or 1 / 5~1 of the value of the 1C current (in A).

5. The cylindrical battery as described in claim 1, characterized in that, The welding area (in mm²) of the electrical connection part (12) in contact with the positive electrode cover plate (3) is 1 / 8 to 1, or 1 / 5 to 1 of the value of 1C current (in A); the contact area (in mm²) of the connection between the electrical connection part (12) and the disk body (11) is 1 / 8 to 1, or 1 / 5 to 1 of the value of 1C current (in A).

6. The cylindrical battery according to any one of claims 1-5, characterized in that, The cylindrical battery also includes a housing (4), the top of which has an opening (41), the positive electrode cover (3) is fixed at the opening (41), and the core (2) is located inside the housing (4).

7. The cylindrical battery as described in claim 6, characterized in that, The cylindrical battery also includes a negative electrode current collector (5), and the bottom of the core (2) is provided with a negative electrode tab (22). The negative electrode current collector (5) is located inside the housing (4), and the two sides of the negative electrode current collector (5) are in contact with the negative electrode tab (22) and the inner wall of the housing (4), respectively.

8. The cylindrical battery as described in claim 6, characterized in that, The cylindrical battery also includes an insulating sealing ring (6), an insulating gasket (7), and an explosion-proof sheet (8). The insulating sealing ring (6) is arranged around the outer edge of the positive electrode cover plate (3) and is located between the positive electrode cover plate (3) and the inner wall of the housing (4). The insulating gasket (7) is disposed on the top surface of the positive electrode current collector (1) and is located between the positive electrode current collector (1) and the inner wall of the housing (4). The explosion-proof sheet (8) is sealed to the top surface of the positive electrode cover plate (3).

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