Over-current protection connecting sheet and battery

Abstract

The utility model discloses an overcurrent protection connecting piece and a battery, which belong to the technical field of batteries, and comprise a connecting piece main body provided with a through hole; a first fusing part and a second fusing part are respectively formed from the two ends of the through hole in the length direction to the edge of the connecting piece main body, the overcurrent lengths of the first fusing part and the second fusing part are respectively b and c, and b + c is more than or equal to 5mm and less than or equal to 14mm; the over-current area of the first fusing part and the over-current area of the second fusing part are smaller than the over-current area of the rest part of the connecting piece body. The battery comprises the over-current protection connecting piece. According to the connecting piece, the battery is discharged under the same condition, the temperature of the first fusing part and the temperature of the second fusing part are the highest, the first fusing part and the second fusing part are rapidly fused to disconnect the circuit, and the fusing efficiency is high.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to an overcurrent protection connector and a battery. Background Technology

[0002] With the increasing maturity of battery technology, power batteries are widely used in electric vehicles, leading to increasingly stringent requirements for their performance and safety. Power batteries are susceptible to risks such as thermal runaway. When an internal short circuit or other abnormal situation occurs, the battery is typically connected to the circuit. If this connection is not promptly disconnected, it may cause a short circuit and damage to the entire circuit, further increasing the potential losses.

[0003] To reduce losses caused by battery thermal runaway, existing technologies typically incorporate a fusible link design for the connecting piece. This fusible link breaks the circuit at high temperatures. For example, Chinese patent document CN113764799A discloses a single-cell battery, a battery module, and a battery pack. In this design, the terminal connecting piece includes two protective sections, each located on one side of the terminal connecting piece. These protective sections are situated between the terminal connecting piece and the tab connecting piece. Current flowing from the tab connecting piece to the terminal connecting piece must pass through these protective sections. Each protective section has a through-hole, allowing current to pass only through both sides of the through-hole. The cross-sectional area at the current-carrying point is small, enabling the temperature of the protective section on both sides of the through-hole to rise rapidly to the melting point of the terminal connecting piece and melt when the current is too high.

[0004] Although the protective part of the connecting piece can be melted on both sides of the through hole, the location of the protective part, i.e. the melting area, is not the area with the highest temperature, resulting in low melting efficiency. Utility Model Content

[0005] The purpose of this invention is to provide an overcurrent protection connector and battery, which solves the problem that in the prior art, the protection part of the connector can be melted at the position on both sides of the through hole, but the position of the protection part, i.e. the melted area, is not the area with the highest temperature, resulting in low melting efficiency.

[0006] To achieve the above objectives, this utility model provides an overcurrent protection connecting piece, including a connecting piece body, wherein the connecting piece body is provided with a through hole; a first fusible portion and a second fusible portion are respectively formed at both ends of the through hole along its length to the edge of the connecting piece body, and the overcurrent area of ​​the first fusible portion and the second fusible portion is smaller than the overcurrent area of ​​the rest of the connecting piece body.

[0007] With the above technical solution, under the same conditions of battery discharge, the overcurrent area of ​​the first fuse and the second fuse is smaller than that of the rest. When the current is too large, the temperature of the first fuse and the second fuse can rise rapidly and the temperature is the highest relative to other parts, so that the first fuse and the second fuse melt and disconnect the circuit, resulting in high melting efficiency.

[0008] Furthermore, the connecting piece body has a thinning area around the through hole, the area of ​​which covers the area where the first fused portion and / or the second fused portion are located; or, the connecting piece body has a thinning area located in the area where the first fused portion and / or the second fused portion are located.

[0009] The thinned area is thinner than other parts of the connecting piece, making it more likely to melt at the melting point, thus improving battery safety. Furthermore, the thinned area saves material and reduces the weight of the connecting piece, thereby increasing the battery's energy density.

[0010] Furthermore, the thinning area is thinned on one side of the connecting piece body, or the thinning area is thinned on both sides of the connecting piece body and the thinning areas on both sides are symmetrically arranged.

[0011] The thinning zone can reduce the thickness of the connecting piece body by thinning on one side or both sides. The symmetrical arrangement of the thinning zone on both sides facilitates processing and has a good thinning effect on the connecting piece body, making the melting feedback of the first melting part and the second melting part more sensitive, which can further improve the melting efficiency.

[0012] Furthermore, the thinning area is covered with a heat-resistant insulating layer, and the sum of the thickness of the heat-resistant insulating layer and the thickness of the thinning area is less than the thickness of the connecting piece body.

[0013] The high-temperature resistant insulation layer maintains its insulation function despite the high temperature resistance, preventing the tabs from still overlapping after the first and second fusible sections melt, thus avoiding the risk of continued current flow. The sum of the thickness of the high-temperature resistant insulation layer and the thinned area is less than the thickness of the connecting piece body, ensuring that the overall thickness of the fusible area does not exceed the thickness of the connecting piece body, and does not affect the assembly of the connecting piece and the cover plate. Simultaneously, it also reduces the weight of the connecting piece body.

[0014] Furthermore, the heat-resistant insulating layer covers the area where the through hole is located; or, the heat-resistant insulating layer covers the area where the thinned region is located, excluding the through hole.

[0015] When a heat-resistant insulating layer covers through-holes, its insulation performance is enhanced. When a heat-resistant insulating layer covers the area outside the through-holes, the material of the heat-resistant insulating layer can be saved while ensuring insulation performance.

[0016] Furthermore, the connecting piece body is covered with a heat-resistant insulating layer on one or both sides.

[0017] The heat-resistant insulation layer can be applied to one or both sides to accommodate thinning areas, thereby enhancing the safety of the thinned areas.

[0018] Furthermore, the overcurrent lengths of the first and second fuse parts are b and c, respectively, where 5mm ≤ b + c ≤ 14mm.

[0019] When the sum of the current-passing lengths of the first and second fuse parts is between 5 mm and 14 mm, the first and second fuse parts have the highest temperatures and the highest fusing efficiency when a large current passes through them.

[0020] Furthermore, the connecting piece body has tab connecting portions on both sides, the tab connecting portions are welded to the tabs to form weld marks, and the weld marks are located outside the thinning area.

[0021] The weld marks are outside the thinning zone, which can prevent the connecting piece body from being welded through when the electrode tab is welded to the connecting piece body, thus ensuring the structural strength of the connecting piece body and the electrode tab.

[0022] Furthermore, there are two through holes, each located inside the tab connection portion; the main body of the connecting piece is provided with a pole connection portion, which is located between the two through holes.

[0023] When the terminal connection part is connected to the terminal, the terminal can be partially embedded in the main body of the connecting piece. Compared with the terminal being connected to the surface of the main body of the connecting piece, this can reduce the space occupied, reduce the volume of the cover plate structure, and improve the utilization rate of the internal space of the battery.

[0024] Furthermore, the pole connection part overlaps with the thinning area, and the pole connection part also has a relatively thin thickness, thereby reducing the space occupied when the pole and the connecting piece body are connected.

[0025] This utility model also provides a battery, including the overcurrent protection connecting piece described above.

[0026] The battery uses the aforementioned overcurrent protection connector. When a short circuit occurs inside the battery, the connector can quickly melt and break, protecting the battery and reducing damage.

[0027] Compared with existing known technologies, the technical solution provided by this utility model has the following beneficial effects:

[0028] This utility model discloses an overcurrent protection connector. When the sum of the overcurrent lengths of the first and second fuse parts is between 5mm and 14mm, under the same battery discharge conditions, the temperatures of the first and second fuse parts are the highest. Furthermore, the overcurrent areas of the first and second fuse parts are smaller than the overcurrent areas of the remaining parts. When the current is too high, the temperatures of the first and second fuse parts can rise rapidly and are the highest relative to other parts, causing the first and second fuse parts to melt and break the circuit, resulting in high melting efficiency.

[0029] It is obvious that the elements or features described in the above individual embodiments can be used alone or in combination in other embodiments. Attached Figure Description

[0030] The dimensions and scales in the accompanying drawings do not represent the dimensions and scales of the actual product. The drawings are for illustrative purposes only, and some non-essential elements or features have been omitted for clarity.

[0031] Figure 1 This is a schematic diagram of the connecting piece in an embodiment of this utility model;

[0032] Figure 2 This is a schematic diagram of the connection structure between the connecting piece and the outer electrode in an embodiment of this utility model;

[0033] Figure 3 This is a three-dimensional structural diagram of the connecting piece and the outer electrode in an embodiment of this utility model;

[0034] Figure 4 This is a temperature cloud map of the connecting piece in this embodiment of the invention at a magnification of 0.22C.

[0035] Figure 5 This is a temperature cloud map of the connecting piece in this embodiment of the invention at a magnification of 0.4C.

[0036] Figure 6 This is a temperature cloud map of the connecting piece in this embodiment of the invention at a magnification of 0.6C.

[0037] Explanation of reference numerals in the attached figures

[0038] 100. Connecting piece body; 110. Through hole; 120. First fusible part; 130. Second fusible part; 140. Electrode tab connecting part; 150. Thinning area; 160. Electrode post connecting part; 170. Weld mark; 200. Outer electrode tab. Detailed Implementation

[0039] The present invention will now be described in detail with reference to the accompanying drawings. The embodiments described herein are merely preferred embodiments of the present invention. Those skilled in the art can conceive of other ways to implement the present invention based on the preferred embodiments, and such other ways also fall within the scope of the present invention.

[0040] Example

[0041] Reference Figures 1-3 This embodiment provides an overcurrent protection connector, including a connector body 100 with a through hole 110. A first fusing portion 120 and a second fusing portion 130 are formed at both ends of the through hole 110 along its length, extending to the edge of the connector body 100. The overcurrent lengths of the first fusing portion 120 and the second fusing portion 130 are b and c, respectively, where 5mm ≤ b + c ≤ 14mm. The overcurrent area of ​​the first fusing portion 120 and the second fusing portion 130 is smaller than the overcurrent area of ​​the rest of the connector body 100. When the current is too high, the temperature of the first fusing portion 120 and the second fusing portion 130 can rise rapidly and reach the highest temperature relative to other parts, causing the first fusing portion 120 and the second fusing portion 130 to melt and disconnect the circuit, resulting in high fusing efficiency. Under the same battery discharge conditions, when the sum of the overcurrent lengths of the first fusing portion 120 and the second fusing portion 130 is between 5mm and 14mm, the temperature of the first fusing portion 120 and the second fusing portion 130 is the highest. It is understandable that the two ends of the through hole 110 along its length direction to the edge of the connecting piece body 100 are the outer edges of the connecting piece body 100 along the length direction of the through hole 110, which can improve the flexibility of the arrangement of the through hole 110.

[0042] Specifically, the values ​​of the overcurrent length b+c can be 5.2mm, 8.8mm, and 13.3mm, and the temperature distribution at different locations during 1.5C discharge is simulated using software. The cell specifications are 330Ah, the outer tab 200 is 2mm thick, and the ambient and initial temperature is 25℃.

[0043] The table below shows a comparison of the highest temperatures of various components at discharge rates of 0.22C, 0.4C, and 0.6C (unit: °C).

[0044]

[0045] From the above data, it can be seen that the temperature of the core exceeds 55°C, and the temperature of the structural member reaches above 60°C. The highest temperature of the structural member is at the positive connection tab. Therefore, the over-current lengths of the first fusing portion 120 and the second fusing portion 130 of the positive connection tab are b and c respectively. When 5mm ≤ b + c ≤ 14mm, the first fusing portion 120 and the second fusing portion 130 can reach the highest temperature and have the highest fusing efficiency. It should be noted that when the value of b + c is 5mm and 14mm, the same simulation results as when the value of b + c is 5.2mm and 13.3mm are also obtained. As Figure 4 , Figure 5 and Figure 6 shown, the simulation diagram of the positive connection tab shows that the area with the highest temperature is located at the positions of the first fusing portion 120 and the second fusing portion 130.

[0046] It should be noted that in addition to the long-strip structure, the through-hole 110 can also be designed into other shapes as long as it can meet the over-current requirement. For example, the through-hole 110 can be designed into a triangle, a circle or a "day" shape, etc. At the same time, some convex structures or serrated structures can be designed on the long side or short side of the through-hole 110 to increase the structural strength of the connection tab without affecting the over-current effect.

[0047] In some embodiments, as Figure 1 shown, the connection tab body 100 is provided with a thinning area 150 around the through-hole 110, and the area of the thinning area 150 covers the area where the first fusing portion 120 and / or the second fusing portion 130 is located. Alternatively, the connection tab body 100 is provided with a thinning area 150, and the thinning area 150 is located in the area where the first fusing portion 120 and / or the second fusing portion 130 is located. The thickness of the thinning area 150 is less than the thickness of other parts of the connection tab body 100. Therefore, when reaching the fusing temperature, the part of the thinning area 150 is more likely to fuse, which can improve the safety of the battery. In addition, the thinning area 150 saves materials and can reduce the weight of the connection tab, thereby improving the energy density of the battery.

[0048] Furthermore, there are various schemes for the thinning design of the thinning area 150. In some embodiments, the thinning area 150 is thinned on one side of the connection tab body 100, so that the thinning area 150 is recessed into the connection tab body 100, and the thinning area 150 has a smaller thickness. In another embodiment, the thinning area 150 is thinned on both sides of the connection tab body 100 and the thinning areas 150 on both sides are symmetrically arranged, and the symmetrical structure is convenient for processing. Whether it is thinned on one side or both sides can reduce the thickness of the connection tab body 100, making the fusing feedback of the first fusing portion 120 and the second fusing portion 130 more sensitive and further improving the fusing efficiency.

[0049] Understandably, while the melting of the connecting piece can break the circuit, there is still a risk that the melted connecting piece may re-connect and continue to conduct electricity. Therefore, a safety redundancy structure is incorporated into the thinned region 150 of the connecting piece. In some embodiments, the thinned region 150 is covered with a heat-resistant insulating layer. The heat-resistant insulating layer's insulation and temperature resistance still enable it to perform its insulating function, preventing the outer tab 200 from still connecting to the connecting piece after the first melting part 120 and the second melting part 130 melt, thus avoiding the risk of current continuing to flow. Furthermore, the sum of the thickness of the heat-resistant insulating layer and the thickness of the thinned region 150 is less than the thickness of the connecting piece body 100. This ensures that the overall thickness of the melting area does not exceed the thickness of the connecting piece body 100, without affecting the assembly of the connecting piece and the cover plate. Simultaneously, it also reduces the weight of the connecting piece body 100.

[0050] It should be noted that the area where the heat-resistant insulating coating is arranged can be determined according to the actual structural strength and current requirements of the connecting piece body 100. In some embodiments, the heat-resistant insulating layer covers the area where the through hole 110 is located, which can enhance the insulation performance. Alternatively, the heat-resistant insulating layer covers the area where the thinned region 150 is located, excluding the through hole 110. When the through hole 110 is melted by the first fusion portion 120 and the second fusion portion 130, the through hole 110 naturally has no connecting part, so the heat-resistant insulating layer does not need to cover the location of the through hole 110, thereby saving the material of the heat-resistant insulating layer. It can be understood that the connecting piece body 100 is covered with a heat-resistant insulating layer on one or both sides to adapt to the thinned region 150 which is thinned on one or both sides, thereby enhancing the safety of the thinned region 150. The material of the heat-resistant insulating layer is preferably a ceramic material, and the material of the connecting piece body 100 is preferably an aluminum alloy.

[0051] In some embodiments, such as Figure 2 As shown, the connecting piece body 100 has electrode connecting portions 140 on both sides. The electrode connecting portions 140 are welded to the outer electrode 200 to form a weld mark 170, which is located outside the thinning zone 150. The weld mark 170 being located outside the thinning zone 150 prevents the connecting piece body 100 from being welded through when the outer electrode 200 is welded to the connecting piece body 100, thus ensuring the structural strength of the connecting piece body 100 and the outer electrode 200.

[0052] In some embodiments, such as Figure 1As shown, two through holes 110 are provided and are located inside the tab connection portion 140 respectively; the connecting piece body 100 is provided with a terminal post connection portion 160, which is located between the two through holes 110. In the event that the first fusible portion 120 and the second fusible portion 130 near the through hole 110 melt, both sides of the terminal post connection portion 160 are disconnected, resulting in higher safety. When the terminal post connection portion 160 is connected to the terminal post, the terminal post can be partially embedded in the connecting piece body 100, which reduces space occupation compared to the terminal post being connected to the surface of the connecting piece body 100, reducing the volume of the cover plate structure and improving the utilization rate of the battery's internal space. Furthermore, the terminal post connection portion 160 partially overlaps with the thinning region 150, and the terminal post connection portion 160 also has a relatively thin thickness, further reducing the space occupied when the terminal post and the connecting piece body 100 are connected.

[0053] Another aspect of this application provides a battery including the aforementioned overcurrent protection connector, the connection of which can be quickly melted when the current is too high, protecting the battery safety and reducing losses.

[0054] In the description of this utility model, it should be noted that the terms "front," "rear," "left," "right," "upper," "lower," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0055] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0056] The scope of protection of this utility model is defined only by the claims. Thanks to the teachings of this utility model, those skilled in the art will readily recognize that alternative structures to the disclosed structure can be used as feasible alternative implementations, and that the disclosed implementations can be combined to produce new implementations, which also fall within the scope of the appended claims.

Claims

1. An overcurrent protection connector, characterized in that, The device includes a connecting piece body (100) having a through hole (110); a first fusible portion (120) and a second fusible portion (130) are formed at both ends of the through hole (110) along its length to the edge of the connecting piece body (100), respectively; the flow area of ​​the first fusible portion (120) and the second fusible portion (130) is smaller than the flow area of ​​the rest of the connecting piece body (100).

2. The overcurrent protection connector according to claim 1, characterized in that, The connecting piece body (100) has a thinning area (150) around the through hole (110), and the area of ​​the thinning area (150) covers the area where the first fused part (120) and / or the second fused part (130) are located; Alternatively, the connecting piece body (100) may be provided with a thinning area (150), which is located in the area where the first fused portion (120) and / or the second fused portion (130) are located.

3. The overcurrent protection connector according to claim 2, characterized in that, The thinning zone (150) is thinned on one side of the connecting piece body (100).

4. The overcurrent protection connector according to claim 2, characterized in that, The thinning area (150) is thinned on both sides of the connecting piece body (100), and the thinning areas (150) on both sides are symmetrically arranged.

5. An overcurrent protection connector according to any one of claims 2-4, characterized in that, The thinning area (150) is covered with a heat-resistant insulating layer, the sum of the thickness of the heat-resistant insulating layer and the thickness of the thinning area (150) being less than or equal to the thickness of the connecting piece body (100).

6. The overcurrent protection connector according to claim 5, characterized in that, The heat-resistant insulating layer covers the area where the thinned region (150) is located, excluding the through hole (110).

7. An overcurrent protection connector according to claim 5, characterized in that, The connecting piece body (100) is covered with a heat-resistant insulating layer on one or both sides.

8. The overcurrent protection connector according to claim 1, characterized in that, The flow lengths of the first fuse section (120) and the second fuse section (130) are b and c, respectively, with 5mm ≤ b + c ≤ 14mm.

9. An overcurrent protection connector according to claim 2, characterized in that, The connecting piece body (100) is provided with tab connecting parts (140) on both sides. The tab connecting parts (140) are welded to the tabs to form weld marks (170). The weld marks (170) are located outside the thinning area (150).

10. An overcurrent protection connector according to claim 9, characterized in that, There are two through holes (110), which are located inside the tab connection part (140); the connecting piece body (100) is provided with a pole connection part (160), which is located between the two through holes (110).

11. An overcurrent protection connector according to claim 10, characterized in that, The pole connection (160) partially overlaps with the thinning region (150).

12. A battery, characterized in that, Includes the overcurrent protection connector as described in any one of claims 1-11.

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