Electric connection sheet and battery assembly

Abstract

The utility model relates to an electric connection sheet and a battery assembly, the electric connection sheet comprises a main body sheet, and the main body sheet is provided with a laser welding zone; the tab connecting sheets are positioned on two transverse sides of the main body sheet, and connecting parts are arranged between the tab connecting sheets and the main body sheet; the groove is formed in the main body piece or the connecting part, a fusing part is formed on at least one side of the groove, the length of the fusing part is smaller than half of the transverse width of the main body piece, the over-current cross sectional area of the electric connecting piece can be reduced, and when a short circuit occurs in the battery assembly, the electric connecting piece can be prevented from being damaged. The fusing part of the electric connecting sheet can be fused in a short time to cut off the internal circuit of the battery cell, so that the internal temperature of the battery cell is controlled not to continuously rise, the pole part of the top cover of the battery cell is ensured not to leak liquid, the thermal runaway risk of the battery cell is reduced, and the safety of the battery assembly is improved.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to an electrical connector and a battery assembly. Background Technology

[0002] The new energy market is becoming increasingly competitive, with power lithium batteries and energy storage batteries developing rapidly. The market is starting to pursue large-capacity single cells, and companies are gradually improving capacity from aspects such as cell raw materials and structural components. Along with the increase in cell energy density, cell safety has become a major concern, requiring assurance that cells will not experience thermal runaway during use. Square cells on the market generally use connecting tabs as a bridge between the cell tabs and the top cover terminals. These connecting tabs are typically butterfly-shaped with a large current-carrying cross-section. If a short circuit occurs, the current through the connecting tabs and top cover terminals can exceed 3000A. When the current is too high, the physical heat generated by the structural components can produce tens of thousands of joules of heat within tens of seconds. During a short circuit, the physical heat generated can reach around 600°C, enough to soften or melt the top cover seal and plastic, causing leakage at the terminals. Once leakage occurs, the electrolyte comes into contact with air, and at high temperatures, the cell is prone to catching fire. Utility Model Content

[0003] This utility model provides an electrical connector and a battery assembly to solve at least one of the above-mentioned technical problems.

[0004] This utility model provides an electrical connector, including a main body sheet with a laser welding area; tab connecting pieces located on both sides of the main body sheet in the lateral direction, with a connecting portion between the tab connecting pieces and the main body sheet; and a groove disposed on the main body sheet or the connecting portion, wherein at least one side of the groove forms a fusion break portion, and the length of the fusion break portion is less than half the lateral width of the main body sheet.

[0005] In one embodiment, the groove extends through the main body piece or the connecting portion along the thickness direction of the main body piece or the connecting portion.

[0006] In one embodiment, the main body sheet includes a main body portion and a protrusion portion, the protrusion portion protruding outward from both sides of the main body portion laterally, and the protrusion portion being connected to the connecting portion.

[0007] In one embodiment, the groove extends longitudinally from the edges of the protrusion and the connecting portion, and the fused portion is located on one side of the bottom of the groove.

[0008] In one embodiment, the groove extends longitudinally from the surface of the protrusion, and the fused portion is located on both sides of the groove in the longitudinal direction.

[0009] In one embodiment, the grooves are provided in multiple longitudinal directions, and the fusion portion is provided between adjacent grooves and on both sides of the longitudinal direction of the grooves.

[0010] In one embodiment, the groove is disposed on the main body portion, the groove extends in an arc shape along the outer periphery of the laser welding area, and the fusion portion is located on both sides of the groove laterally.

[0011] In one embodiment, the sum of the lengths of the fused portions in the longitudinal or transverse directions is less than half the transverse width of the main body portion.

[0012] In one embodiment, the width of the groove is 0.5 mm to 5 mm.

[0013] This utility model also provides a battery assembly, including a cell top cover, a winding core, and the aforementioned electrical connecting piece, wherein the electrode post of the cell top cover is welded to the laser welding area, and the electrode tab of the winding core is connected to the electrode connecting piece.

[0014] Compared with the prior art, the advantages of this utility model are that a groove is provided on the main body sheet or the connecting part, and a fusible part is formed on at least one side of the groove. The length of the fusible part is less than half of the lateral length of the main body sheet. This can reduce the cross-sectional area of ​​the electrical connecting piece for overcurrent, so that when a short circuit occurs inside the battery assembly, the fusible part of the electrical connecting piece can melt and break the internal circuit of the cell in a short time, thereby controlling the internal temperature of the cell to stop rising continuously, ensuring that the terminal part of the cell top cover does not leak, reducing the risk of thermal runaway of the cell, and thus improving the safety of the battery assembly. Attached Figure Description

[0015] The present invention will be described in more detail below based on embodiments and with reference to the accompanying drawings.

[0016] Figure 1 This is a schematic diagram of the structure of the electrical connector piece according to the first embodiment of this utility model;

[0017] Figure 2 This is a schematic diagram of the structure of the electrical connector piece according to the second embodiment of this utility model;

[0018] Figure 3 This is a schematic diagram of the structure of the electrical connector piece according to the third embodiment of this utility model;

[0019] Figure 4 This is a schematic diagram of the structure of the electrical connector piece according to the fourth embodiment of this utility model;

[0020] Figure 5 This is a schematic diagram of the structure of the battery assembly of this utility model;

[0021] Figure label:

[0022] 1. Body sheet; 11. Laser welding area; 12. Body part; 13. Protruding part; 2. Tab connecting sheet; 21. Connecting part; 22. Ultrasonic welding area; 3. Groove; 4. Fusing part; 5. Cell top cover; 6. Winding core; 61. Tab; 7. Negative connecting sheet. Detailed implementation manner

[0023] The present utility model will be further described below in conjunction with the accompanying drawings.

[0024] As Figure 1 shown, the present utility model provides an electrical connecting sheet, which includes a body sheet 1 in the shape of a flat plate. The body sheet 1 is provided with a laser welding area 11. Tab connecting sheets 2 are respectively provided on the two lateral sides of the body sheet 1 in the transverse direction. A connecting part 21 is provided between the tab connecting sheet 2 and the body sheet 1. A groove 3 is provided on the body sheet 1 or the connecting part 21. A fusing part 4 is formed on at least one side of the groove 3. The length of the fusing part 4 is less than half of the transverse width of the body sheet 1, which can reduce the cross-sectional area of the current passing through the electrical connecting sheet. When a short circuit occurs inside the battery assembly, the fusing part 4 of the electrical connecting sheet can be fused in a short time to cut off the internal circuit of the battery assembly, thereby controlling the temperature inside the battery assembly from rising continuously, ensuring that the pole column part of the cell top cover 5 does not leak liquid, reducing the risk of thermal runaway of the cell core, and thus improving the safety of the battery assembly.

[0025] The electrical connecting sheet is made of an aluminum sheet or a copper sheet, or made of other conductive materials. Preferably, the electrical connecting sheet is integrally formed from a sheet material, which can facilitate rapid processing and forming.

[0026] Preferably, the groove 3 penetrates through the body sheet 1 or the connecting part 21 along the thickness direction of the body sheet 1 or the connecting part 21, so that current cannot pass through at this groove 3 position, forming a partition area. Then the current concentrates on passing through the fusing part 4 on one side of the groove 3. When a short circuit occurs, the large current instantly fuses the fusing part 4, thereby cutting off the internal circuit of the battery and avoiding the safety hazard of continuous heat generation causing high-temperature fire.

[0027] The whole body sheet 1 is in a "convex" shape. The body sheet 1 includes a body part 12 and a protruding part 13. The protruding part 13 protrudes outward from the two lateral edges of the body part 12 in the transverse direction. The protruding part 13 is connected to the connecting part 21 and is flush with the connecting part 21. In one embodiment, the body sheet 1 and the tab connecting sheet 2 are located on the same plane, then the body sheet 1, the connecting part 21 and the tab connecting sheet 2 are all located on the same plane, and the whole electrical connecting sheet is in a flat plate shape. In another embodiment, the body sheet 1 and the tab connecting sheet 2 are located on different planes, then the connecting part 21 connecting the body sheet 1 and the tab connecting sheet 2 is bent.

[0028] The tab connecting sheet 2 is provided with an ultrasonic welding area 22 and is welded to the tab 61 of the winding core 6 by ultrasonic welding.

[0029] Embodiment 1

[0030] like Figure 1 As shown, in this embodiment, the groove 3 is an open groove that extends longitudinally from the edge of the protrusion 13 and the connecting part 21. The fuse part 4 is located on the bottom side of the groove 3. The position of this fuse part 4 is the narrowest current-passing position. The length b of the fuse part 4 is less than half of the lateral width a of the main body 12, i.e., b < 1 / 2a, to ensure that the high current melts at the position of the fuse part 4 in the event of a short circuit, thereby avoiding the high current from generating heat around the laser welding area 11, which would cause the sealing ring and plastic of the cell top cover 5 connected to the laser welding area 11 to soften or melt, thereby causing the electrode to leak and generate a high temperature fire safety risk.

[0031] Example 2

[0032] like Figure 2 As shown, in this embodiment, the groove 3 is a closed groove, and the groove 3 is longitudinally opened from the surface of the protrusion 13. The fusing part 4 is located on both sides of the longitudinal direction of the groove 3. The protrusion 13 on both sides of the main body 12 is provided with a groove 3, and two fusing parts 4 are formed on the longitudinal sides of the groove 3.

[0033] Preferably, the sum of the lengths of the two fusing portions 4 (b1+b2) is less than half the lateral width a of the main body 12, i.e., (b1+b2) < 1 / 2a. Therefore, when a high current passes through the fusing portions 4, both fusing portions 4 can be melted simultaneously. Furthermore, since the sum of the lengths of the two fusing portions 4 is less than half the lateral width of the main body 12, the safety risks caused by heat generation of current in the laser welding area 11 can also be avoided.

[0034] Example 3

[0035] like Figure 3 As shown, the only difference from Embodiment 2 is that the grooves 3 are provided in multiple intervals along the longitudinal direction, and the fusion section 4 is provided between adjacent grooves 3 and on both sides of the longitudinal direction of the grooves 3. Moreover, the sum of the lengths of the multiple fusion sections 4 along the longitudinal direction (b1+b2+b3) is less than half of the transverse width a of the main body 12, that is, (b1+b2+b3) < 1 / 2a.

[0036] Example 4

[0037] like Figure 4 As shown, in this embodiment, the groove 3 is provided on the main body 12, and the groove 3 extends arcuately along the outer periphery of the laser welding area 11. The fusing portion 4 is located on both sides of the groove 3 in the lateral direction. Moreover, the sum of the lengths of the two fusing portions 4 in the lateral direction (b1+b2) is less than half of the lateral width a of the main body 12, that is, (b1+b2) < 1 / 2a. Since the width is narrowest at the fusing portions 4 on both sides, the high current will preferentially melt the fusing portion 4, and will not generate heat at the laser welding area 11 to cause a fire.

[0038] Preferably, the width of the groove 3 is 0.5mm to 5mm.

[0039] The electrical connector of this invention, by providing a groove 3 on the main body 1 or the connecting part 21, with a fusible portion 4 formed on at least one side of the groove 3, can reduce the cross-sectional area of ​​the electrical connector for overcurrent. Furthermore, the length of the fusible portion 4 is less than half the lateral length of the main body 1. When a short circuit occurs in the battery, the current preferentially melts at the narrowest point of the fusible portion 4, preventing high current from generating heat around the laser welding area 11, which could cause the sealing ring and plastic of the cell top cover 5 connected to the laser welding area 11 to soften or melt, thus posing a safety risk of leakage and high-temperature fire. When a short circuit occurs inside the battery assembly, the fusible portion 4 of the electrical connector can melt and break the internal circuit of the cell in a short time, thereby controlling the internal temperature of the cell to prevent further rise, ensuring no leakage at the terminal of the cell top cover 5, reducing the risk of thermal runaway of the cell, and thus improving the safety of the battery assembly.

[0040] This utility model also provides a battery assembly, including a cell top cover 5, a winding core 6, and the aforementioned electrical connecting piece. The electrical connecting piece serves as a positive electrode connecting piece and is electrically connected to the cell top cover 5 and the winding core 6, respectively. The cell top cover 5 and the winding core 6 are carried by the electrical connecting piece. The terminal of the cell top cover 5 is welded to the laser welding area 11, and the electrode tab 61 of the winding core 6 is welded to the electrode tab connecting piece 2. The battery assembly also includes a negative electrode connecting piece 7, which is a copper sheet. The negative electrode connecting piece 7 also has a laser welding area and an electrode tab welding area, and is welded to the cell top cover 5 and the winding core 6, respectively. In this embodiment, the electrical connecting piece serves as a positive electrode connecting piece. In other embodiments, the electrical connecting piece can also serve as a negative electrode connecting piece, or simultaneously as both a positive and negative electrode connecting piece.

[0041] During battery assembly manufacturing, the tabs 61 of the core 6 are first placed on the tab connecting pieces 2 of the positive and negative electrode connecting pieces, and ultrasonic welding is performed in the ultrasonic welding area 22. Then, the laser welding area 11 of the welded electrical connecting piece is aligned with the terminal post of the cell top cover 5, and the terminal post is fitted to the laser welding area 11 for laser welding. After adhesive treatment of the welding area, the core is rolled up, and processes such as film insulation treatment, casing welding, film covering and patching are performed to assemble the finished cell, which is the battery assembly. Since the fusion section 4 of the electrical connecting piece in this battery assembly is the narrowest and has a small overcurrent cross-sectional area, it can melt and break at the location of the fusion section 4 for a short time when a large current passes through, cutting off the internal circuit of the battery assembly. According to Joule's law and the specific heat capacity formula, the shorter the circuit breaking time, the lower the heat and temperature, which will not affect the stability of the terminal post. It can also prevent the leakage caused by the failure of the terminal post sealing of the cell top cover 5, reducing the risk of thermal runaway of the cell.

[0042] Although the present invention has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of the invention. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. An electrical connector, characterized in that, include: The main body sheet has a laser welding area; Electrode connecting pieces are located on both sides of the main body piece laterally, and a connecting portion is provided between the electrode connecting pieces and the main body piece; and A groove is provided on the main body piece or the connecting portion, and a fused portion is formed on at least one side of the groove, the length of which is less than half the lateral width of the main body piece.

2. The electrical connector according to claim 1, characterized in that: The groove extends through the main body piece or the connecting part along the thickness direction of the main body piece or the connecting part.

3. The electrical connector according to claim 1, characterized in that, The main body includes a main body portion and a protruding portion. The protruding portion protrudes outward from both sides of the main body portion in a horizontal direction and is connected to the connecting portion.

4. The electrical connector according to claim 3, characterized in that, The groove extends longitudinally from the edges of the protrusion and the connecting portion, and the fused portion is located on one side of the bottom of the groove.

5. The electrical connector according to claim 3, characterized in that, The groove is longitudinally formed from the surface of the protrusion, and the fused portion is located on both sides of the longitudinal direction of the groove.

6. The electrical connector according to claim 5, characterized in that, The grooves are provided in multiple longitudinal directions, and the fusion section is provided between adjacent grooves and on both sides of the longitudinal direction of the grooves.

7. The electrical connector according to claim 3, characterized in that, The groove is provided on the main body and extends in an arc along the outer periphery of the laser welding area. The fusion section is located on both sides of the groove in the lateral direction.

8. The electrical connector according to claim 5, 6, or 7, characterized in that, The sum of the lengths of the fused portions in the longitudinal or transverse direction is less than half the transverse width of the main body portion.

9. The electrical connector according to claim 1, characterized in that, The width of the groove is 0.5mm to 5mm.

10. A battery assembly, characterized in that, include: The battery cell top cover, the winding core, and the electrical connector as described in any one of claims 1-8, wherein the electrode post of the battery cell top cover is welded to the laser welding area, and the electrode tab of the winding core is connected to the electrode tab connector.

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