Positive electrode connector, battery cell and battery

Abstract

This invention provides a positive electrode connecting piece, including a first connecting piece, a second connecting piece, and a fuse. The first connecting piece is used to connect to the cell terminal; the second connecting piece is connected to the first connecting piece via the fuse and is used to connect to the electrode tab; the ratio of the cross-sectional area of ​​the fuse to the cell capacity is X, where X ranges from 0.064 to X ≤ 0.076. By setting the fuse between the first connecting piece and the two sets of second connecting pieces, when the current passing through the positive electrode connecting piece is too large, the fuse automatically melts, breaking the internal circuit of the cell and preventing problems such as cell fire and explosion. When dealing with cells of different capacities, the range of values ​​for the cross-sectional area of ​​the fuse can be obtained by multiplying the cell capacity by 0.064 and 0.076 respectively, facilitating the rapid determination of a reasonable range for the cross-sectional area of ​​the fuse.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to a positive electrode connector, a battery cell, and a battery thereof. Background Technology

[0002] The positive electrode connector of a battery cell is a core conductive component that is directly connected to the positive electrode tab (or terminal) of the battery cell. It is the "first contact" for the transmission of current from inside the cell to the outside. Its design, material and connection quality directly determine the conductivity, safety and service life of the battery cell. It is widely used in the manufacturing of battery cells for various secondary batteries such as lithium-ion batteries and sodium-ion batteries.

[0003] In existing technologies, the overcurrent cross-sectional area of ​​the positive electrode connector in conventional battery cells is approximately 41 mm². 2 However, it lacks a fusible link, and when the current passing through the positive electrode connector is too large, it cannot break the internal circuit of the cell, which can easily lead to problems such as cell fire and explosion. Therefore, to address the above technical problems, a positive electrode connector, a cell, and a battery are proposed. Utility Model Content

[0004] To address the shortcomings of existing technologies, this utility model proposes a positive electrode connector, a battery cell, and a battery. By incorporating a fusible link, the fusible link can automatically melt and break the circuit inside the battery cell when the current passing through it is too high, thus preventing problems such as battery cell fires and explosions. Furthermore, it facilitates the rapid determination of a reasonable range for the cross-sectional area of ​​the fusible link when dealing with battery cells of different capacity specifications.

[0005] A positive electrode connector, comprising: The first connecting piece is used to connect to the battery cell terminal; The second connecting piece is connected to the first connecting piece via a fusible part, and the second connecting piece is used to connect to the electrode tab; The ratio of the cross-sectional area of ​​the fuse to the cell capacity is X, and the range of X is 0.064≤X≤0.076.

[0006] The beneficial effects of the above-mentioned positive electrode connector are as follows: By setting a fuse between the first connecting piece and the two sets of second connecting pieces, when the current passing through the positive electrode connecting piece is too large, the fuse will automatically melt and break the circuit inside the cell, thus avoiding problems such as cell fire and explosion. When dealing with cells of different capacity specifications, the range of values ​​for the cross-sectional area of ​​the fuse can be obtained by multiplying the cell capacity by 0.064 and 0.076 respectively, which makes it easy to quickly determine the reasonable range of the cross-sectional area of ​​the fuse.

[0007] In one embodiment, X is in the range of 0.070 ≤ X ≤ 0.076. This ensures that the fuse automatically melts when the current is too high, while avoiding the risk of accidental melting when the cross-sectional area of ​​the fuse is too small and the normal operating current fluctuates.

[0008] In one embodiment, X = 0.076. While ensuring that the fuse automatically melts in the event of excessive current, the cross-sectional area of ​​the fuse is maximized, thereby increasing the cell's current limit, voltage stability, long-term lifespan, and reducing the risk of overheating.

[0009] In one embodiment, the fusible portion forms two sides with the first connecting piece and the second connecting piece, and at least one of the two sides has a notch. When the current is too large, the current density at the notch is the highest, and the heat generated is the most concentrated, which can preferentially reach the fusing temperature, ensuring that the fusible portion breaks at the preset position, avoiding incomplete circuit breaking due to fusing position deviation, or damage to the effective connection area of ​​the first or second connecting piece; and the number and size of the notches can be flexibly adjusted, and the fusing speed can be customized according to the overload current characteristics of the battery cell, such as the peak value and duration of the overload current: the larger the notch and the smaller the local cross-sectional area, the faster the fusing speed, which can be adapted to small-capacity battery cells with extremely fast overload response requirements; the smaller the notch, the slower the fusing speed, which can avoid false fusing caused by instantaneous current fluctuations that are not true overloads, and is adapted to the complex working scenarios of large-capacity battery cells.

[0010] In one embodiment, the first connecting piece, the second connecting piece, and the fused portion have the same thickness. The entire positive electrode connecting piece can be processed through a single stamping process, reducing process steps and improving production efficiency. At the same time, consistent thickness avoids uneven mold wear caused by thickness differences, extends mold life, and reduces production costs.

[0011] In one embodiment, the first connecting piece, the second connecting piece, and the fused portion are all made of the same material, namely aluminum.

[0012] In one embodiment, a roughened portion is provided on one side of the first connecting piece. By providing the roughened portion, the reflectivity of the first connecting piece can be reduced during laser welding, thereby preventing the laser head from absorbing the reflected light from the surface of the first connecting piece and burning it.

[0013] In one embodiment, the roughened portion includes pits, and the first connecting piece has an array of pits on one side. By arraying the pits, multiple diffuse reflections occur inside the pits during laser welding, thereby prolonging the residence time of energy in the local area, significantly increasing the energy absorption rate per unit area, ensuring that the laser energy is precisely applied to the welding area, thus reducing energy waste and avoiding welding defects caused by insufficient energy.

[0014] A battery cell comprising the positive electrode connecting piece as described in any one of the above.

[0015] A battery comprising the aforementioned battery cell. Attached Figure Description

[0016] To more clearly illustrate the specific embodiments of this utility model, the accompanying drawings used in the specific embodiments will be briefly described below. In all the drawings, the elements or parts are not necessarily drawn to scale.

[0017] Figure 1 This is a front view of a positive electrode connector provided in an embodiment of the present invention; Figure 2 for Figure 1 An enlarged schematic diagram of region A in the middle.

[0018] Figure label: 10. First connecting piece; 20. Second connecting piece; 30. Fusible part; 40. Notch; 50. Textured part; 501. Dent. Detailed Implementation

[0019] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0020] Please see Figure 1 One embodiment of a positive electrode connector includes a first connector 10, a second connector 20, and a fuse 30. Specifically, the first connector 10 is used to connect to the battery cell terminal. The second connector 20 is connected to the first connector 10 via the fuse 30, and the second connector 20 is used to connect to the electrode tab. The ratio of the cross-sectional area of ​​the fuse 30 to the battery cell capacity is X, where X ranges from 0.064 to X ≤ 0.076. The cross-sectional area is in mm². 2 The unit for battery cell capacity is Ah.

[0021] In the above embodiment, by providing a fuse 30 between the first connecting piece 10 and the two sets of second connecting pieces 20, when the current passing through the positive electrode connecting piece is too large, the fuse 30 automatically melts, breaking the internal circuit of the battery cell and preventing problems such as battery cell fire and explosion. When dealing with battery cells of different capacity specifications, the range of values ​​for the cross-sectional area of ​​the fuse 30 can be obtained by multiplying the battery cell capacity by 0.064 and 0.076 respectively, which facilitates the quick determination of the reasonable range of the cross-sectional area of ​​the fuse 30. For example, if the battery cell capacity is 280Ah, then the reasonable range of the cross-sectional area of ​​the fuse 30 of the positive electrode connecting piece is: 280 (Ah) × 0.064 - 280 (Ah) × 0.076, which is 17.92 (mm²).2 -21.28 (mm) 2 ).

[0022] Experimental procedure: Understandably, the positive electrode connector melting test is one of the key tests in battery safety testing and design verification. Its core purpose is to evaluate the melting performance of the positive electrode connector between cells under extreme conditions such as overcurrent and short circuit, and to verify whether it can cut off the fault circuit in time through timely melting, so as to prevent the cell from thermal runaway, fire or even explosion caused by continuous high current.

[0023] When an excessive current (far exceeding the rated current carrying capacity of the connector) occurs in the circuit, the resistance of the positive electrode connector itself will generate a large amount of heat. When the rate of heat accumulation exceeds the rate of heat dissipation, the temperature of the positive electrode connector will rapidly rise to the melting point of its material (e.g., pure nickel has a melting point of about 1455°C, and aluminum about 660°C), eventually melting and breaking, thus cutting off the current circuit.

[0024] Cell performance testing is a systematic verification of indicators such as the cell's electrical performance (capacity, rate capability, voltage plateau), safety (short circuit, overcharge, needle penetration), and reliability (cycle life, high and low temperature performance).

[0025] There is a core relationship of mutual constraint and matching between battery cell performance testing and the cross-sectional area of ​​the positive electrode connector's fused section: the fused section area is a "hidden variable" affecting the accuracy of battery cell performance test results, while the core performance indicators of battery cells (such as rate capability, safety, and cycle life) in turn determine the design threshold of the fused section area. The degree of matching between the two directly affects the validity of test data and the reliability of battery cells in actual applications.

[0026] Short-circuit safety testing (such as external short circuit and internal short circuit simulation) is a crucial test to verify whether a battery cell will catch fire or explode under short-circuit fault conditions. The "protection threshold" of the fuse cross-sectional area directly determines the success or failure of the test. Cross-sectional area design matching (optimal state): The fusing current threshold is between the "maximum current for normal cell operation" and the "dangerous current for cell short circuit".

[0027] Excessive cross-sectional area (excessive fusing current): The fuse cannot melt in time, and the short-circuit current continues to act on the cell, causing the internal temperature of the cell to rise sharply (exceeding the decomposition temperature of the electrolyte and the decomposition temperature of the active material), which leads to thermal runaway (fire, explosion).

[0028] Insufficient cross-sectional area (insufficient fusing current): Even during normal high-current testing (such as 3C discharge), the current may reach the fusing threshold, causing the connector to melt accidentally, forcing the test to be interrupted, and making it impossible to complete an effective evaluation of the cell performance.

[0029] Furthermore, the range of X is 0.070≤X≤0.076. This ensures that the fuse 30 can automatically melt when the current is too high, while avoiding the risk of the fuse 30 having a small cross-sectional area and accidentally melting when the normal operating current fluctuates.

[0030] Furthermore, X = 0.076. While ensuring that the fuse 30 can automatically melt in case of excessive current, the cross-sectional area of ​​the fuse 30 is maximized, thereby increasing the upper limit of the current, voltage stability, and long-term lifespan of the battery cell, and reducing the risk of overheating.

[0031] Please see Figure 1 In one embodiment, the fuse portion 30 forms two sides with the first connecting piece 10 and the second connecting piece 20. At least one of the two sides has a notch 40. When the current is too large, the current density at the notch 40 is the highest, and the heat generated is the most concentrated, which can preferentially reach the melting temperature, ensuring that the fuse portion 30 is disconnected at the preset position, avoiding incomplete circuit breaking due to the displacement of the melting position, or damage to the effective connection area of ​​the first connecting piece 10 or the second connecting piece 20; and the number and size of the notches 40 can be flexibly adjusted, and the melting speed can be customized according to the overload current characteristics of the battery cell, such as the peak value and duration of the overload current: the larger the notch 40, the smaller the local cross-sectional area, and the faster the melting speed, which can be adapted to small-capacity battery cells with extremely fast overload response requirements; the smaller the notch 40, the slower the melting speed, which can avoid false melting caused by instantaneous current fluctuations that are not true overloads, and is adapted to the complex working scenarios of large-capacity battery cells.

[0032] Please see Figure 1 In one embodiment, the first connecting piece 10, the second connecting piece 20, and the fused portion 30 have the same thickness. The first connecting piece 10, the second connecting piece 20, and the fused portion 30 are all made of the same material, aluminum. The entire positive electrode connecting piece can be processed through a single stamping process, reducing process steps and improving production efficiency. Simultaneously, the consistent thickness avoids uneven mold wear caused by thickness differences, extending mold life and reducing production costs.

[0033] Please see Figure 1 In one embodiment, a roughened portion 50 is provided on one side of the first connecting piece 10. By providing the roughened portion 50, the reflectivity of the first connecting piece 10 can be reduced during laser welding, thereby preventing the laser head from absorbing the reflected light from the surface of the first connecting piece 10 and burning it.

[0034] Please see Figure 1 and Figure 2In one embodiment, the roughened portion 50 includes recesses 501, and the first connecting piece 10 has an array of recesses 501 on one side. By arraying the recesses 501, during laser welding, multiple diffuse reflections occur inside the recesses 501 when the laser is irradiated, thereby prolonging the residence time of energy in the local area, significantly improving the energy absorption rate per unit area, ensuring that the laser energy is accurately applied to the welding area, thereby reducing energy waste and avoiding welding defects caused by insufficient energy.

[0035] In one embodiment, the battery cell includes the positive electrode connecting piece of the above embodiment. When the current passing through the positive electrode connecting piece is too large, the fuse part 30 automatically melts to break the internal circuit of the battery cell, thereby avoiding problems such as battery cell fire and explosion and improving the safety of the battery cell.

[0036] One embodiment of the battery includes the battery cell described in the above embodiment. When the current passing through the battery cell is too large, the fuse 30 automatically melts to break the internal circuit of the battery cell, thereby avoiding problems such as battery cell fire and explosion, and improving battery safety.

[0037] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model, and they should all be covered within the scope of the claims and specification of this utility model.

Claims

1. A positive electrode connector, characterized in that, include: The first connecting piece (10) is used to connect to the battery cell terminal; The second connecting piece (20) is connected to the first connecting piece (10) via a fusible part (30), and the second connecting piece (20) is used to connect to the electrode tab; The ratio of the cross-sectional area of ​​the fuse (30) to the cell capacity is X, and the range of X is 0.064≤X≤0.

076.

2. The positive electrode connector according to claim 1, characterized in that, The range of X is 0.070 ≤ X ≤ 0.

076.

3. A positive electrode connector according to claim 2, characterized in that, X＝0.076。 4. A positive electrode connector according to claim 1, characterized in that, The fused portion (30) forms two sides with the first connecting piece (10) and the second connecting piece (20), and at least one of the two sides has a notch (40).

5. A positive electrode connector according to claim 1, characterized in that, The thicknesses of the first connecting piece (10), the second connecting piece (20), and the fused portion (30) are the same.

6. A positive electrode connector according to claim 1, characterized in that, The first connecting piece (10), the second connecting piece (20), and the fused part (30) are all made of the same material, aluminum.

7. A positive electrode connector according to claim 1, characterized in that, A textured part (50) is provided on one side of the first connecting piece (10).

8. A positive electrode connector according to claim 7, characterized in that, The textured part (50) includes recesses (501), and the first connecting piece (10) has recesses (501) arrayed on one side.

9. A battery cell, characterized in that, Includes the positive electrode connector as described in any one of claims 1-8.

10. A battery, characterized in that, Includes the battery cell as described in claim 9.

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