Battery packs and electrical devices

Abstract

This invention provides a battery pack and an electrical device, relating to the field of battery technology. The battery pack includes multiple pouch cells and connecting tabs. Each pouch cell includes a cell, a casing, and a current output terminal. The current output terminal is bonded to and sealed to the casing. A first end of the current output terminal is electrically connected to a cell, and the connection forms the outer edge of the current output terminal. The connecting tab electrically connects the current output terminals of at least two pouch cells. The current output terminals are welded to the connecting tab to form a first welding area. The resistivity of the connecting tab is less than the resistivity of the current output terminals. Along the lead-out direction of the current output terminals, the length between the outer edge of the first end of the current output terminal and the first welding area along the current transmission direction forms a current-carrying length A mm. The resistivity of the connecting tab is T Ωmm² / m, and the thickness of any current output terminal is D mm. 0.6 ≤ AT / D ≤ 24.04. This technical solution solves the problem in related technologies where pouch cells cannot meet the requirements for high-rate charging and discharging.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more specifically, to a battery pack and an electrical device. Background Technology

[0002] In recent years, with the rapid development of the electronic devices and electric vehicle industries, consumers' demand for fast battery charging has been increasing. Fast charging technology shortens charging time, providing a faster charging solution for electric vehicles. However, the implementation of fast charging technology places higher demands on the battery's charge and discharge rates, requiring the battery to withstand large currents of charging and discharging in a short period of time.

[0003] Pouch batteries, with their advantages of being lightweight, thin, flexible, having high energy density, and good safety, have been widely used in portable electronic devices, electric vehicles, energy storage systems, and other fields. Pouch batteries can be designed into various shapes, offering high adaptability to different product requirements.

[0004] However, under high-rate charge and discharge conditions, the internal resistance of the pouch battery is relatively high, resulting in a slow current transmission rate, which cannot meet the requirements of high-rate charge and discharge. Summary of the Invention

[0005] The main objective of this invention is to provide a battery pack and an electrical device to solve the problem that pouch batteries in related technologies cannot meet the requirements of high-rate charging and discharging.

[0006] To achieve the above objectives, according to one aspect of the present invention, a battery pack is provided, comprising a plurality of pouch cells and a connecting piece. The pouch cell includes a cell, a casing, and a current output terminal. The cell is disposed within the casing, and the current output terminal is bonded to and sealed to the casing. A first end of the current output terminal is electrically connected to the cell, and the connection between the first end of the current output terminal and the cell forms the outer edge of the current output terminal. A second end of the current output terminal extends out of the casing. The connecting piece electrically connects the current output terminals of at least two pouch cells. The current output terminal is welded to the connecting piece to form a first welding area, and the resistivity of the connecting piece is less than the resistivity of the current output terminal. Wherein, along the lead-out direction of the current output terminal, the length between the outer edge of the first end of the current output terminal and the first welding area along the current transmission direction forms a current-carrying length Amm, and the resistivity of the connecting piece is TΩ. mm² / m, thickness D mm for any current output terminal. Overcurrent length A mm, resistivity T Ω for the connecting piece. The thickness Dmm of the current output terminal and the mm² / m of the current output terminal satisfy: 0.6≤A T / D≤24.04.

[0007] According to another aspect of the present invention, an electrical device is provided, including a battery pack, wherein the battery pack is the battery pack described above.

[0008] By applying the technical solution of this invention, a connecting piece is welded to the current output terminals of at least two pouch cells, and the resistivity of the connecting piece is lower than that of the current output terminals. This reduces the resistance when connecting the current output terminals of at least two pouch cells, allowing for electrical connection through the connecting piece with lower resistivity. This reduces the overall resistance of the battery pack, increases the current transmission rate, and facilitates meeting the requirements of high-rate charging and discharging. Furthermore, the overcurrent length Amm formed by controlling the length along the current transmission direction between the outer edge of any current output terminal and the first welding area, and the resistivity TΩ of the connecting piece, are all controlled. The relationship between mm² / m and the thickness Dmm of any current output terminal ensures optimized current transmission speed while maintaining the sealing performance of the pouch battery casing. Specifically, when A When the T / D value is too small, the thickness Dmm of the current output terminal accounts for too large a proportion in the formula. This can easily lead to the welding area between the battery cell and the current output terminal and the first welding area being too close, causing localized heating of the insulation layer and resulting in seal failure between the current output terminal and the casing. When A When the value of T / D is too large, the overcurrent length Amm and / or the resistivity TΩ of the connecting piece will be affected. If the proportion of mm² / m in this formula is too large, the overall resistance of the battery pack may be high. When the overcurrent length A mm and the resistivity of the connecting piece T Ω are... When the thickness Dmm of the current output terminal and the mm² / m of the battery pack meet the above conditions, the current transmission rate of the battery pack under high-rate charge and discharge will be improved, reducing the overall resistance of the battery pack. This enables it to meet the requirements of high-rate charge and discharge, solving the problem of slow current transmission rate of pouch batteries under high-rate charge and discharge in related technologies. Therefore, the above technical solution effectively solves the problem that pouch batteries in related technologies cannot meet the requirements of high-rate charge and discharge. Attached Figure Description

[0009] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0010] Figure 1 A three-dimensional structural schematic diagram of an embodiment of the battery pack according to the present invention is shown;

[0011] Figure 2 It shows Figure 1 A magnified view of a portion of the battery pack at point A;

[0012] Figure 3 It shows Figure 1A magnified view of a portion of the battery pack's connection points;

[0013] Figure 4 It shows Figure 1 A partial enlarged view of the battery pack when the insulating wire harness plate is not shown;

[0014] Figure 5 It shows Figure 1 A partial cross-sectional view of the battery pack;

[0015] Figure 6 It shows Figure 1 A three-dimensional structural diagram of the soft-pack battery in the battery pack;

[0016] Figure 7 It shows Figure 1 A partial schematic diagram of the first welding area of ​​the battery pack.

[0017] The above figures include the following reference numerals:

[0018] 10. Soft-pack battery; 11. Housing; 111. Housing body; 112. Housing sealing layer; 12. Current output terminal; 121. Side edge; 122. First output section; 123. Second output section; 124. Outer edge;

[0019] 20. Connecting piece;

[0020] 31. First bonding wire; 32. Second bonding wire;

[0021] 40. Insulating wire harness plate; 41. First through hole; 411. First side wall; 412. Second side wall; 42. Second through hole. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0024] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0025] The inventors discovered that the current overcurrent bottleneck of pouch batteries in related technologies is mainly due to the fact that their current output terminals are mostly sheet-like structures. Furthermore, the shape of the pouch battery casing limits the size of the electrode sheets, resulting in a small current overcurrent cross-sectional area. This makes it difficult to meet the current demand for high-rate fast charging, which leads to a slower charging and discharging rate for pouch batteries. At high rates, the overall resistance of pouch batteries increases, affecting the overall charging time and safety of pouch batteries during high-rate charging and discharging.

[0026] In this embodiment, as Figures 1 to 7 As shown, the battery pack includes multiple pouch cells 10 and connecting pieces 20. Each pouch cell 10 includes a cell, a casing 11, and a current output terminal 12. The cell is disposed within the casing 11. The current output terminal 12 is bonded to and sealed to the casing 11. The first end of the current output terminal 12 is electrically connected to the cell, and the connection between the first end of the current output terminal 12 and the cell forms the outer edge 124 of the current output terminal 12. The second end of the current output terminal 12 extends out of the casing 11. The connecting piece 20 electrically connects the current output terminals 12 of at least two pouch cells 10. The current output terminals 12 are welded to the connecting piece 20 to form a first welding area. The resistivity of the connecting piece 20 is less than the resistivity of the current output terminals 12. Along the current output direction, the length between the outer edge 124 of the first end of the current output terminal 12 and the first welding area along the current transmission direction forms a current-carrying length A mm. The resistivity of the connecting piece 20 is TΩ. mm² / m, the thickness of any current output terminal 12 is D mm. Overcurrent length A mm, resistivity of connecting piece 20 T Ω. The thickness Dmm of the current output terminal 12 and the mm² / m of the current output terminal 12 satisfy: 0.6≤A T / D≤24.04.

[0027] In this way, the connecting piece 20 is welded to the current output terminals 12 of at least two pouch cells 10, and the resistivity of the connecting piece 20 is less than that of the current output terminals 12. This reduces the resistance when connecting the current output terminals 12 of the at least two pouch cells 10, allowing them to be electrically connected via the lower resistivity of the connecting piece 20. This lowers the overall resistance of the battery pack, increases the current transmission rate, and facilitates meeting the requirements of high-rate charging and discharging. Furthermore, the overcurrent length Amm formed by controlling the length along the current transmission direction between the outer edge 124 of any current output terminal 12 and the first welding area, and the resistivity TΩ of the connecting piece 20, are all controlled. The relationship between mm² / m and the thickness Dmm of any current output terminal 12 ensures optimized current transmission speed while maintaining the sealing performance of the housing 11 of the pouch battery 10. Specifically, when A When the T / D value is too small, the thickness Dmm of the current output terminal 12 accounts for too large a proportion in the formula. This can easily lead to the welding area between the battery cell and the current output terminal and the first welding area being too close, causing localized heating of the insulation layer and resulting in sealing failure between the current output terminal 12 and the housing 11. When A When the value of T / D is too large, the resistivity TΩ of the overcurrent length Amm and / or the connecting piece 20 will be affected. If the proportion of mm² / m in this formula is too large, the overall resistance of the battery pack may be high. When the overcurrent length is A mm and the resistivity of the connecting piece 20 is TΩ... When the thickness Dmm of the current output terminal 12 meets the above conditions (mm² / m), the current transmission rate of the battery pack under high-rate charging and discharging will be improved, reducing the overall resistance of the battery pack. This enables it to meet the requirements of high-rate charging and discharging, solving the problem of slow current transmission rate of pouch batteries under high-rate charging and discharging in related technologies. Therefore, the above embodiment effectively solves the problem that pouch batteries in related technologies cannot meet the requirements of high-rate charging and discharging.

[0028] It should be noted that, all other things being equal, the higher the resistivity, the higher the resistance. The overcurrent length Amm and the thickness Dmm of the current output terminal 12 in the T / D formula refer to the parameters of the same current output terminal 12 on the same pouch cell 10, rather than the overcurrent length Amm of one current output terminal 12 and the thickness Dmm of another different current output terminal 12. Furthermore, the current output terminals 12 of at least two pouch cells 10 connected to the connecting piece 20 all meet the range requirements of the above formula.

[0029] It should be noted that the resistivity TΩ of the connecting piece 20 in this application is... The measurement method for mm² / m is as follows: Connecting piece 20 is made of metal, and its conductivity σ is tested according to GB / T32791-2016 and GB / T12966-2022. The resistivity TΩ of connecting piece 20... mm² / m is the reciprocal of conductivity σ, calculated using the formula T = 1 / σ. The unit of resistivity T for connecting piece 20 is Ω. mm² / m. The resistivity T of the connecting piece 20 is controlled as follows: Resistivity T is determined by the scattering mechanism experienced by electrons moving in the crystal lattice. It can be controlled by adjusting the doping elements of the metal material and the preparation method. For example, high-purity smelting can be used to reduce the content of impurity atoms (such as iron (Fe), sulfur (S), boron (P), etc.) in the metal material; the proportion of alloying elements can be controlled; the material can be annealed; the annealing time can be extended to coarsen the grains in the material; and a highly conductive layer can be deposited on the surface of the metal substrate to reduce contact resistance. These methods can reduce the resistivity T of the material.

[0030] It should be noted that the bonding and sealing connection between the current output terminal 12 and the housing 11 means that: the part of the current output terminal 12 located inside the current output terminal 12 is directly heat-fused to the housing 11; or, an insulating part is provided between the part of the current output terminal 12 located inside the current output terminal 12 and the housing 11, and the insulating part is heat-fused to the housing, and the insulating part is bonded to the current output terminal.

[0031] It should be noted that the connection piece 20 electrically connecting to the current output terminals 12 of at least two pouch batteries 10 means that the connection piece 20 is welded to the second end of the current output terminals 12 of at least two pouch batteries 10, or the connection piece 20 is welded to the middle of the current output terminals 12 of at least two pouch batteries 10.

[0032] It should be noted that welding the current output terminal 12 to the connecting piece 20 to form a first welding area means that at least two current output terminals 12 overlap and are welded to the electrode piece to form a first welding area. Alternatively, at least two current output terminals 12 are welded to the electrode piece respectively to form at least two first welding areas, each first welding area including one or more welding wires.

[0033] It should be noted that the current output terminal 12 has a sheet-like structure. The current output terminal 12 can be set straight or bent to form a bent section. The lead-out direction of the current output terminal 12 is horizontal. Therefore, when calculating the overcurrent length Amm, if the current output terminal 12 has a bent part, the overcurrent length Amm is the distance from the outer edge 124 of the first end of the current output terminal 12 to the first welding area after the bent part is flattened.

[0034] In this embodiment, the current flow length Amm is preferably in the range of 25mm ≤ Amm ≤ 100mm. The resistivity TΩ of the connecting piece 20 is... The preferred range for mm² / m is 1.71. 10 -2 Ω mm² / m≤TΩ mm² / m≤6 10 -2 Ω mm² / m. The thickness Dmm of the current output terminal 12 is preferably in the range of 0.2mm ≤ Dmm ≤ 0.8mm. A The maximum range for T / D calculation is 0.53 ≤ A T / D≤30.0. A The preferred range for T / D is 0.6 ≤ A T / D≤24.04. A The further preferred range for T / D is 2.03 ≤ A T / D≤18.93. A The preferred T / D values ​​are 0.6, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, 12.0, 13.0, 14.0, 15.0, 16.0, 17.0, 18.0, 19.0, 20.0, 21.0, 22.0, 23.0, 24.0, or 24.04.

[0035] like Figures 2 to 4 As shown, the first welding area includes a first welding line 31 and a second welding line 32 spaced apart. The spaced first welding line 31 and the second welding line 32 increase the overall welding strength of the first welding area, ensuring the long-term reliability and safety of the battery pack. The arrangement of the first welding line 31 and the second welding line 32 avoids heat concentration during welding caused by an excessively large overall size of the first welding area, thereby reducing the risk of welding failure at the current output terminal 12 due to heat concentration. It also avoids heat concentration during welding, which could affect the sealing performance between the casing and the current output terminal.

[0036] In this embodiment, the extension direction of the first bonding wire 31 is perpendicular to the lead-out direction of the current output terminal 12. The extension direction of the second bonding wire 32 is perpendicular to the lead-out direction of the current output terminal 12. The first bonding wire 31 and the second bonding wire 32 are spaced apart along an arrangement direction parallel to the pouch battery.

[0037] like Figures 2 to 4As shown, a first spacing distance L1mm is formed between the first welding wire 31 and the second welding wire 32, which satisfies the condition: 1.0mm ≤ L1mm ≤ 10.0mm. This first spacing distance L1mm ensures a reasonable distance between the first welding wire 31 and the second welding wire 32. This design not only helps avoid the risk of localized overheating during welding due to an excessively small first spacing distance L1mm, but also prevents damage to the current output terminal 12, poor welding, and failure of the casing seal due to excessively high local temperatures. If the first spacing distance L1mm is too large, the effective contact area between the connecting piece 20 and the current output terminal 12 will decrease, the current transmission path will increase, and the overall resistance of the pouch battery 10 will increase, affecting the current transmission efficiency of the battery pack. Furthermore, an appropriate first spacing distance L1mm also ensures that the first welding area has sufficient mechanical strength, preventing weld breakage due to external impact or vibration during battery pack use, thereby improving the overall stability and safety of the battery pack.

[0038] Preferably, the first interval distance L1mm is 1.0mm, 1.5mm, 2.0mm, 2.5mm, 3.0mm, 3.5mm, 4.0mm, 4.5mm, 5.0mm, 5.5mm, 6.0mm, 6.5mm, 7.0mm, 7.5mm, 8.0mm, 8.5mm, 9.0mm, 9.5mm or 10.0mm.

[0039] like Figures 1 to 4 As shown, multiple pouch cells 10 are arranged along a preset direction, and the length direction of the first welding area is perpendicular to the preset direction. The design of the arrangement direction of the multiple pouch cells 10 and the length direction of the first welding area ensures that the welding area between the current output terminal 12 and the connecting piece 20 is maximized, thereby achieving efficient current transmission between the pouch cells 10. The first welding area, which is perpendicular to the preset direction, not only forms a continuous weld and increases the welding area, but also improves the current transmission rate and reduces the overall resistance of the battery pack.

[0040] In this embodiment, multiple pouch cells 10 are arranged along a preset direction, such as... Figure 1 As shown in X1. The length direction of the first welding zone is as follows. Figure 2 As shown in X2.

[0041] like Figures 2 to 4 as well as Figure 6As shown, the current output terminal 12 has two spaced-apart side edges 121 along the length direction of the first welding area. Along the length direction of the first welding area, the first welding area and at least one side edge 121 of the current output terminal 12 are spaced apart. By spaced the first welding area and the side edges 121, not only is the heat effect during the welding process dispersed, preventing welding quality problems caused by localized overheating, but also sufficient current flow path is ensured, reducing the internal resistance of the battery pack and improving the current transmission efficiency of the battery pack.

[0042] like Figure 2 As shown, along the length of the first welding area, a second gap distance L2mm is formed between the first welding area and the side edge 121 of the current output terminal 12. The second gap distance L2mm satisfies: 2.0mm ≤ L2mm ≤ 15.0mm. By setting a reasonable range for the second gap distance L2mm, the welding strength between the current output terminal 12 and the connecting piece 20 can be ensured while avoiding thermal stress concentration caused by the welding area being too close to the side edge 121 of the current output terminal 12, thereby reducing the risk of damage to the current output terminal 12 during the welding process. By reasonably setting the second gap distance L2mm, the mechanical strength and welding yield of the current output terminal 12 can be effectively balanced, while avoiding the risk of seal failure of the casing sealing section, thereby improving the overall performance and reliability of the battery pack.

[0043] Preferably, the second interval distance L2mm is 2.0mm, 2.5mm, 3.0mm, 3.5mm, 4.0mm, 4.5mm, 5.0mm, 5.5mm, 6.0mm, 6.5mm, 7.0mm, 7.5mm, 8.0mm, 8.5mm, 9.0mm, 9.5mm, 10.0mm, 10.5mm, 11.0mm, 11.5mm, 12.0mm, 12.5mm, 13.0mm, 13.5mm, 14.0mm, 14.5mm, or 15.0mm.

[0044] like Figures 2 to 4 As shown, the end of the connecting piece 20 along the length of the first welding area protrudes from at least one side edge 121 of the current output terminal 12. This structural design helps to ensure the connection strength between the connecting piece 20 and the current output terminal 12, and also ensures the stable transmission of current between the connecting piece 20 and the current output terminal 12.

[0045] like Figures 2 to 4As shown, the end of the connecting piece 20 protrudes from the side edge 121 of the current output terminal 12 along the length direction of the first welding area by a distance L3mm, which satisfies the condition: 5.0mm ≤ L3mm ≤ 50.0mm. By reasonably controlling the upper limit of the protrusion distance L3mm, excessive space occupied by the connecting piece 20 inside the battery pack can be avoided, ensuring the compactness of the overall battery pack structure and space utilization. By reasonably controlling the lower limit of the protrusion distance L3mm, the connection strength between the connecting piece 20 and the current output terminal 12 can be guaranteed. Controlling the protrusion distance L3mm between 5.0mm and 50.0mm can balance the reliability of electrical connection and the optimization of the internal layout of the battery pack, achieving a reasonable internal layout of the battery pack without sacrificing connection strength.

[0046] Preferably, the protrusion distance L3mm is 5.0mm, 10.0mm, 15.0mm, 20.0mm, 25.0mm, 30.0mm, 35.0mm, 40.0mm, 45.0mm or 50.0mm.

[0047] Furthermore, the battery pack also includes a signal acquisition terminal, which is welded to the connecting piece 20 to form a second welding area. The second welding area and the first welding area are spaced apart along the length of the first welding area. This design enables the acquisition of battery voltage data through the signal acquisition terminal without affecting current transmission efficiency, thereby monitoring the battery's operating status. Spacing the second welding area between the signal acquisition terminal and the connecting piece 20 and the first welding area avoids occupying excessive space in a predetermined direction, ensuring the compactness of the battery pack.

[0048] In this embodiment, the signal acquisition terminal is a voltage sampling terminal. The voltage sampling terminal is used to acquire the voltage information of the pouch battery. After acquiring the battery signal, the voltage sampling terminal transmits it to the BMS. The voltage sampling terminal can be a metal sheet (e.g., a nickel sheet) or a sheet conductor made of other conductive materials. The voltage sampling terminal is typically planar or spherical in shape.

[0049] Furthermore, the connecting piece 20 is electrically connected to the current output terminals 12 of the two pouch cells 10. The current output terminals 12 of the two pouch cells 10 electrically connected to the connecting piece 20 at least partially overlap. A first welding area forms a weld seam at the point where the current output terminals 12 of the two pouch cells 10 at least partially overlap, and the weld seam extends through the current output terminals 12 of the two pouch cells 10 along the thickness direction. Thus, by designing the weld seam to extend through the current output terminals 12 of the two pouch cells 10 along the thickness direction, the overlapping portion of the current output terminals 12 of the two pouch cells 10 is more tightly connected. Moreover, because the weld seam is located at the overlapping portion of the current output terminals 12 of the two pouch cells 10, the thickness of the current output terminals 12 of the two pouch cells 10 on the connecting piece 20 is greater, reducing the possibility of soldering through the connecting piece 20 and improving the welding yield.

[0050] like Figure 2 As shown, the first welding area has a first length L4mm along its length direction, and the first length L4mm satisfies: 30mm ≤ L4mm ≤ 90mm. By setting the length range of the first length L4mm, sufficient contact can be ensured between the connecting piece 20 and the current output terminal 12, thereby improving the efficiency and stability of current transmission. An excessively short first length L4mm may lead to poor contact between the connecting piece 20 and the current output terminal 12 or increase resistance, affecting the overall performance of the battery pack. An excessively long first length L4mm may increase welding difficulty, resulting in uneven heat distribution during welding and affecting welding quality. Therefore, by controlling the first length L4mm between 30mm and 90mm, good current transmission effect can be ensured while avoiding potential problems during welding, ensuring the fast-charging performance and safety of the battery pack. Preferably, the first length L4mm is 30mm, 35mm, 40mm, 45mm, 50mm, 55mm, 60mm, 65mm, 70mm, 75mm, 80mm, 85mm, or 90mm.

[0051] like Figures 2 to 4 As shown, multiple pouch cells 10 are arranged along a preset direction, and the first welding area includes first welding wires 31 and second welding wires 32 spaced apart along the preset direction. This spaced arrangement of the first welding wires 31 and second welding wires 32 ensures a stable electrical connection between the current output terminal 12 and the connecting piece 20. By providing two independent first welding wires 31 and second welding wires 32 between the current output terminal 12 and the connecting piece 20, not only is the total welding contact area increased, contact resistance reduced, and current transmission efficiency improved, but even if one welding wire experiences poor welding or cracking for some reason, the other welding wire can still maintain circuit continuity, enhancing the reliability of the battery pack.

[0052] Furthermore, the first welding wire 31 has a first width W1mm perpendicular to the length direction of the first welding area, and the first width W1mm satisfies: W1mm≥0.3mm. This further enhances the stability of the welding and the current transmission performance, ensuring the current transmission efficiency and the reliability of the welded connection under different operating conditions, and avoiding the problems of weak welding caused by an excessively narrow first welding wire 31 or increased internal resistance caused by an excessively narrow current transmission path. The second welding wire 32 has a second width W2mm perpendicular to the length direction of the first welding area, and the second width W2mm satisfies: W2mm≥0.3mm. This further enhances the stability of the welding and the current transmission performance, ensuring the current transmission efficiency and the reliability of the welded connection under different operating conditions, and avoiding the problems of weak welding caused by an excessively narrow second welding wire 32 or increased internal resistance caused by an excessively narrow current transmission path.

[0053] In other embodiments, the first bonding wire 31 has a first width W1mm perpendicular to the length direction of the first bonding area, and the first width W1mm satisfies: W1mm≥0.3mm. Alternatively, the second bonding wire 32 has a second width W2mm perpendicular to the length direction of the first bonding area, and the second width W2mm satisfies: W2mm≥0.3mm.

[0054] Preferably, the first width W1mm is 0.3mm, 0.4mm, 0.5mm, 0.6mm or more. The second width W2mm is 0.3mm, 0.4mm, 0.5mm, 0.6mm or more.

[0055] In other embodiments not shown, the connecting piece is electrically connected to the current output terminals of the two pouch cells, and the current output terminals of the two pouch cells form two spaced-apart first welding areas with the connecting piece. These two spaced-apart first welding areas not only ensure good electrical contact between each current output terminal and the connecting piece, but also simplify the battery pack assembly process, reduce production costs, and facilitate subsequent maintenance and testing. The current output terminals of the two pouch cells are spaced apart, meaning they are not stacked.

[0056] In other embodiments not shown, the overcurrent length A mm and the resistivity T Ω of the connecting piece are... The thickness Dmm of the current output terminal and the mm² / m of the current output terminal satisfy: 0.6≤A T / D ≤ 22.0. This reduces the current output voltage (A) by setting the current output terminals of the two pouch cells at different intervals. The upper limit of T / D further reduces the proportion of the overcurrent length Amm in the above formula, thereby shortening the current transmission path and improving the current transmission efficiency.

[0057] Furthermore, the overcurrent length Amm satisfies: 25mm ≤ Amm ≤ 100mm; the resistivity TΩ of the connecting piece 20 mm² / m satisfies: 1.71 10 -2 Ω mm² / m≤TΩ mm² / m≤6 10 -2 Ω The thickness Dmm of the current output terminal 12 satisfies: 0.2mm ≤ Dmm ≤ 0.8mm. These parameters ensure the current transmission efficiency and safety of the battery pack under high-rate charge / discharge conditions. The optimized design of the overcurrent length Amm ensures an appropriate length of current from the outer edge 124 of the current output terminal 12 to the first welding area, reducing energy loss and preventing thermal management problems caused by excessive length. The conductivity setting of the connecting piece 20 effectively reduces the internal resistance of the battery pack, accelerates the current transmission speed, and thus improves the overall charge / discharge rate of the battery pack. The reasonable setting of the thickness Dmm of the current output terminal 12 balances the current carrying capacity and the sealing performance of the battery package, avoiding sealing failure at the connection between the current output terminal 12 and the housing 11 due to excessive thickness of the current output terminal 12, and also preventing a decrease in current transmission capacity due to excessive thinness of the current output terminal 12. By comprehensively considering these three key factors, the battery pack of this embodiment can maintain good sealing and mechanical strength while ensuring electrical performance, providing more stable and efficient current support for electrical devices.

[0058] Preferably, the current-carrying length Amm is 25mm, 30mm, 35mm, 40mm, 45mm, 50mm, 55mm, 60mm, 65mm, 70mm, 75mm, 80mm, 85mm, 90mm, 95mm, or 100mm. The resistivity TΩ of the connecting piece 20 is... The preferred mm² / m is 1.71 10 -2 Ω mm² / m, 1.8 10 -2 Ω mm² / m, 2.0 10 -2 Ω mm² / m, 2.5 10 -2 Ω mm² / m, 3.0 10 -2 Ω mm² / m, 3.5 10 -2 Ω mm² / m, 4.0 10 -2 Ω mm² / m, 4.5 10 -2 Ω mm² / m, 5.0 10 -2 Ω mm² / m, 5.5 10 -2 Ω mm² / m or 6.0 10 -2 Ω mm² / m. The thickness Dmm of the current output terminal 12 is preferably 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm or 0.8mm.

[0059] In other embodiments, the overcurrent length Amm satisfies: 25mm ≤ Amm ≤ 100mm. Alternatively, the resistivity TΩ of the connecting piece 20... mm² / m satisfies: 1.71 10 -2 Ω mm² / m≤TΩ mm² / m≤6 10 -2 Ω mm² / m. Alternatively, the thickness Dmm of the current output terminal 12 satisfies: 0.2mm≤Dmm≤0.8mm.

[0060] like Figures 1 to 3 as well as Figure 5 As shown, the battery pack also includes an insulating wire harness plate 40 disposed on one side of the pouch battery 10. A connecting piece 20 is fixedly disposed on the insulating wire harness plate 40. The insulating wire harness plate 40 has a through hole, and the current output terminal 12 passes through at least partially through the through hole. The second end of the current output terminal 12 is connected to the side of the connecting piece 20 away from the pouch battery 10. This design optimizes the internal spatial layout of the battery pack. By providing a through hole in the insulating wire harness plate 40, not only can the current output terminal 12 be effectively positioned to ensure its precise docking with the connecting piece 20, but it also facilitates the installation operation of the connecting piece 20 and the welding operation between the connecting piece 20 and the current output terminal 12.

[0061] In this embodiment, the material of the insulating wire harness board 40 can be plastic or other insulating materials. The plastic can be polyethylene terephthalate (PET), polypropylene (PP), polycarbonate (PC), polyvinyl chloride (PVC), etc.

[0062] In this embodiment, the connecting piece 20 is fixedly mounted on the insulating wire harness plate 40 by means of bonding, snapping, riveting, screwing or injection molding.

[0063] Furthermore, the thickness Dmm of the current output terminal 12 satisfies: 0.2mm≤Dmm≤0.7mm. Based on the insulated wire harness plate 40, the upper limit of the thickness Dmm of the current output terminal 12 is reduced. This ensures that the current output terminal 12 has sufficient thickness to carry high current density without excessively increasing its thickness. This facilitates the insertion of the current output terminal 12 into the through hole and also facilitates the bending operation of the current output terminal 12 after it has passed through the through hole.

[0064] Preferably, the thickness Dmm of the current output terminal 12 is 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm or 0.7mm.

[0065] like Figure 2 , Figure 3 as well as Figure 5 As shown, multiple pouch cells 10 are arranged along a preset direction. The through holes include a first through hole 41 and a second through hole 42 spaced apart along the preset direction on the insulating wire harness plate 40. The connecting piece 20 is electrically connected to the current output terminals 12 of two pouch cells 10, with the current output terminals 12 of the two pouch cells 10 exiting through the first through hole 41 and the second through hole 42, respectively. The fact that the current output terminals 12 of the two pouch cells 10 exit through the first through hole 41 and the second through hole 42 ensures that the current output terminals 12 of the two pouch cells 10 do not interfere with each other, thus optimizing the current transmission path within the battery pack. Furthermore, the insulating wire harness plate 40 allows the two current output terminals 12 to be bent and connected to the connecting piece 20, avoiding the problem of increased internal resistance of the pouch cells 10 due to excessively long lead-out lengths of the current output terminals 12, which would affect the current transmission rate. By defining the orientation of the spacing between the first through hole 41 and the second through hole 42, the internal structure of the battery pack becomes more compact, achieving efficient current transmission within a limited space. This reduces the internal resistance of the entire battery pack, improving its charging and discharging efficiency and safety. Furthermore, this layout also facilitates a compact battery pack design, saving space.

[0066] like Figure 2 , Figure 3 as well as Figure 5As shown, the first through hole 41 is located on one side of the connecting piece 20 along a preset direction. The first through hole 41 has a first sidewall 411 and a second sidewall 412 spaced apart along the preset direction. The first sidewall 411 is located close to the connecting piece 20, and the second sidewall 412 is located away from the connecting piece 20. The second sidewall 412 and the connecting piece 20 have a first minimum preset distance L5mm along the preset direction. The first minimum preset distance L5mm satisfies: 3.0mm≤L5mm≤10.0mm. This design effectively controls the distance between the second sidewall 412 and the connecting piece 20, ensuring that the current output terminal 12 can smoothly pass through the first through hole 41 without excessive bending or squeezing that could cause breakage. At the same time, by limiting the range of the first minimum preset distance L5mm, the distance between the second sidewall 412 and the connecting piece 20 is prevented from being too large, which would reduce the number of first through holes 41 on the insulating wire harness plate 40, making the structure inside the battery pack more compact and improving the structural strength of the insulating wire harness plate 40.

[0067] like Figures 2 to 5 As shown, the current output terminal 12 includes a first output segment 122 and a second output segment 123 connected at an angle to the first output segment 122. The first output segment 122 is connected to the battery cell, and the second output segment 123 is connected to the connecting piece 20. A bending area is formed between the first output segment 122 and the second output segment 123. There is a second minimum preset distance L6mm between the bending area and the first welding area, and a third minimum preset distance L7mm between the bending area and the outer edge 124. The second minimum preset distance L6mm is less than the third minimum preset distance L7mm. In this way, the bending area of ​​the current output terminal 12 is optimized. By limiting the second minimum preset distance L6mm to be less than the third minimum preset distance L7mm, the mechanical strength of the current output terminal 12 during bending and the reliability of the electrical connection are effectively balanced. Furthermore, the space on one side of the battery cell is effectively utilized, reducing the space occupied in the arrangement direction of multiple soft-pack batteries 10 and improving the structural compactness of the battery pack.

[0068] Furthermore, the sum of the thicknesses of the current output terminals 12 of at least two pouch cells 10 electrically connected to the connecting piece 20 is less than the thickness of the connecting piece 20. This design ensures that the connecting piece 20 has sufficient conductive cross-sectional area to reduce the overall resistance of the battery pack, thereby improving the high-power charging and discharging capability of the battery pack. This thickness configuration strategy further optimizes the electrical performance of the battery pack while ensuring the reliability of the electrical connection, providing the battery pack with higher power operation capability.

[0069] Furthermore, the connecting piece 20 is made of copper or a copper alloy, and the current output terminal 12 is made of nickel or a nickel alloy. The high conductivity of the connecting piece 20, made of copper or a copper alloy, effectively compensates for the insufficient conductivity of the current output terminal 12 of the pouch battery 10, which is made of nickel or a nickel alloy. This reduces the resistance encountered during current transmission, thereby accelerating the current transmission speed and improving the overall energy conversion efficiency of the battery pack. Moreover, the current output terminal 12 is made of nickel or a nickel alloy, which has less reflectivity during welding, resulting in a higher welding yield and improving the welding yield between the current output terminal 12 and the connecting piece 20. The connecting piece 20, made of copper or a copper alloy, has good conductivity, which reduces resistance and increases the current transmission speed.

[0070] In this embodiment, the copper alloy is preferably a copper-aluminum alloy or copper plated with nickel. The nickel alloy is preferably copper plated with nickel or aluminum plated with nickel; or it may contain 90% nickel by mass, and the other components may include other metallic or non-metallic materials.

[0071] It should be noted that the material of the connecting piece 20 includes, but is not limited to, metals such as copper, aluminum, nickel, aluminum alloy, and copper-aluminum alloy, and can also be copper-plated nickel, aluminum-plated nickel, copper-aluminum composite, etc. The material of the current output terminal 12 can be aluminum, nickel, aluminum alloy, or aluminum-plated nickel, etc.

[0072] Furthermore, the current output terminal 12 includes a first metal layer and a second metal layer disposed outside the first metal layer, the second metal layer being nickel or a nickel alloy. The second metal layer, made of nickel or a nickel alloy, has good welding characteristics, which facilitates improving the welding yield when welding the current output terminal 12 to the connecting piece 20, and improves the welding reliability of the current output terminal 12 and the connecting piece 20.

[0073] Furthermore, the conductivity of the first metal layer is greater than that of the second metal layer. This design effectively improves the conductivity of the current output terminal 12 and reduces the resistance during current transmission, while ensuring a high welding yield when welding the current output terminal 12 to the connecting piece 20. This, in turn, improves the overall current transmission efficiency and charge / discharge rate of the battery pack. The high conductivity of the first metal layer, as the main path for current transmission, facilitates rapid current conduction, while the second metal layer improves the welding yield, ensuring the structural stability and electrical reliability of the current output terminal 12. This rational material configuration not only ensures good electrical performance of the current output terminal 12 but also guarantees its welding performance, providing a strong guarantee for the efficient and safe operation of the battery pack.

[0074] like Figure 4 and Figure 5As shown, the housing 11 includes a housing body 111 and a housing sealing layer 112 disposed on one side of the housing body 111. The battery cell is disposed inside the housing body 111. The first end of the current output terminal 12 extends into the housing body 111, and the current output terminal 12 is led out from inside the housing sealing layer 112. The current output terminal 12 is bonded and sealed to the housing sealing layer 112. The direction perpendicular to the lead-out direction of the current output terminal 12 is the second direction. The current output terminal 12 has a third width W3mm along the second direction, and the housing sealing layer 112 has a fourth width W4mm along the second direction. The relationship between the third width W3mm and the fourth width W4mm satisfies: W3 / W4≤0.7. The housing sealing layer 112 ensures the waterproof and dustproof performance at the connection between the housing 11 and the current output terminal 12. The relationship between the third width W3mm and the fourth width W4mm satisfies: W3 / W4≤0.7. This design ensures that the current output terminal 12 has an appropriate embedding width in the housing sealing layer 112, which can not only ensure a good seal between the current output terminal 12 and the housing sealing layer 112, but also avoid the risk of seal failure caused by the current output terminal 12 being too wide, thereby improving the overall reliability of the battery pack.

[0075] In this embodiment, the current output terminal 12 is a sheet-like structure.

[0076] Preferably, W3 / W4 is 0.7, 0.65, 0.6, 0.55, 0.5 or less.

[0077] like Figure 4 and Figure 5 As shown, the housing 11 includes a housing body 111 and a housing sealing layer 112 disposed on one side of the housing body 111. The battery cell is disposed inside the housing body 111. The first end of the current output terminal 12 extends into the housing body 111, and the current output terminal 12 is led out from inside the housing sealing layer 112. The current output terminal 12 is bonded to and sealed with the housing sealing layer 112. The current output terminal 12 has a sheet-like structure. The housing sealing layer 112 has a first end and a second end spaced apart along the lead-out direction of the current output terminal 12. The first end of the housing sealing layer 112 is disposed close to the housing body 111, and the second end of the housing sealing layer 112 is disposed away from the housing body 111. The end face of the first end of the current output terminal 12 protrudes from the end face of the first end of the housing sealing layer 112 in the direction toward the battery cell. The housing sealing layer 112 helps to enhance the sealing performance at the connection between the current output terminal 12 and the housing 11. Meanwhile, the current output terminal 12 protrudes from the end face of the first end of the housing sealing layer 112 in the direction towards the battery cell, making the electrical connection between the current output terminal 12 and the battery cell more reliable, which is conducive to the smooth transmission of current, reduces the resistance of current in the transmission process, and thus improves the charging and discharging efficiency and safety of the battery pack.

[0078] Furthermore, the distance between the end face of the first end of the current output terminal 12 and the end face of the first end of the housing sealing layer 112 is a fourth minimum preset distance, which is greater than or equal to 0.5 mm and less than or equal to 4.0 mm. This design ensures an appropriate distance between the current output terminal 12 and the housing sealing layer 112, guaranteeing effective electrical connection between the battery cells inside the battery and the current output terminal 12, while preventing sealing problems that may occur due to excessively small distances, thus affecting the overall performance of the battery pack. By precisely controlling the range of the fourth minimum preset distance, the battery pack can maintain a low resistance during high-rate charging and discharging, improving the current transmission rate, while ensuring the sealing performance and structural stability of the pouch battery 10.

[0079] Preferably, the fourth minimum preset distance is 0.5mm, 1.0mm, 1.5mm, 2.0mm, 2.5mm, 3.0mm, 3.5mm or 4.0mm.

[0080] Furthermore, the current output terminal 12 includes tabs and electrode plates. The tabs are electrically connected to the battery cell, and the electrode plates are directly connected to the tabs. The overcurrent length Amm satisfies the following condition: 30mm ≤ Amm ≤ 100mm. The electrical connection between the tabs and the battery cell ensures smooth current flow, while the direct connection between the electrode plates and the tabs reduces the resistance when current passes through the current output terminal 12, thereby reducing the internal heat generation of the pouch battery 10 during high-rate charging and discharging, and improving the overall performance and lifespan of the pouch battery 10. With the electrode plates directly connected to the tabs, setting an appropriate overcurrent length Amm ensures smooth current transmission along the path between the current output terminal 12 and the first welding area, avoiding the problem of increased resistance due to an excessively long overcurrent path, thus optimizing the stability and reliability of the battery pack during high-power operation.

[0081] It should be noted that the electrode plate is directly connected to the tab, meaning that the electrode plate and the tab are not connected by any other components.

[0082] Preferably, the flow length Amm is 30mm, 40mm, 50mm, 60mm, 70mm, 80mm, 90mm or 100mm.

[0083] Furthermore, the battery pack also includes an adapter plate. The current output terminal 12 includes tabs and electrode plates. The tabs are electrically connected to the battery cells, and the electrode plates are electrically connected to the tabs via the adapter plate. The thickness Dmm of the current output terminal 12 satisfies the following condition: 0.3mm ≤ Dmm ≤ 0.8mm. By introducing the adapter plate, a stable electrical connection can be established between the tabs and electrode plates, optimizing the current transmission path and further improving the overall performance of the battery pack. The addition of the adapter plate not only enhances the reliability of the connection but also enables effective current dispersion, reducing localized heat generation and extending the battery's lifespan. The thickness Dmm of the current output terminal 12 is designed within this range to ensure smooth and safe current transmission in high-rate charging and discharging scenarios, while also taking into account the packaging process requirements of the pouch battery 10, avoiding welding difficulties caused by excessive thickness or decreased current transmission efficiency caused by excessive thinness.

[0084] Preferably, the thickness Dmm of the current output terminal 12 is 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.50mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, 0.75mm or 0.8mm.

[0085] In this embodiment, the direction of current transmission is shown as X3 in the attached figure. The method for measuring dimensions in this application is as follows: using measuring instruments such as micrometers or calipers to measure parameters such as length, width, distance, and thickness.

[0086] This application also provides an electrical device including a battery pack, which is the aforementioned battery pack. Because the aforementioned battery pack can solve the problem that pouch batteries in related technologies cannot meet the requirements for high-rate charging and discharging, the electrical device having this battery pack can solve the same technical problem.

[0087] The electrical devices covered in this application include, but are not limited to, vehicles, mobile phones, tablets, laptops, ships, spacecraft, electric toys, and power tools. Vehicles can be fuel-powered vehicles, natural gas vehicles, new energy vehicles, or rail vehicles; new energy vehicles can be pure electric vehicles, hybrid vehicles, or range-extended vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric vehicle toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. When the electrical device is a vehicle, the battery pack can be located at the bottom, front, or rear of the vehicle.

[0088] In this embodiment, the current output terminal 12 can be welded to the battery cell, or it can be fixed and electrically connected to the battery cell via an adapter. The current output terminal 12 is electrically connected to the battery cell and leads out from the housing 11 to allow current to be discharged from the battery cell, thus achieving charging and discharging. The current output terminal 12 typically adopts a thin metal sheet structure and is electrically connected to the tabs led out from the end of the battery cell. This electrical connection can be achieved through welding or other connection methods. The current output terminal 12 is made of a highly conductive metallic material (such as one or more of copper, aluminum, nickel, etc., or an alloy thereof).

[0089] In this embodiment, the casing 11 of the soft-pack battery 10 is a multi-layer structure composed of an outer insulating layer, a metal layer, and an inner insulating layer. The outer insulating layer can be made of one or more materials such as polycaprolactam (nylon 6), PET (polyethylene terephthalate), or polybutylene succinate. The metal layer can be made of one or more metals or alloys such as aluminum, aluminum alloy, copper, or nickel. The inner insulating layer can be made of one or more materials such as polypropylene film (PP) or cast polypropylene film (CPP).

[0090] In this embodiment, the battery cell is the component in a pouch battery where electrochemical reactions occur; it is the smallest unit in a pouch battery capable of performing electrochemical reactions such as charging / discharging. The battery cell is the basic unit in a pouch battery and typically includes a positive electrode, a negative electrode, and a separator. Lithium-ion battery cells primarily function by the intercalation and deintercalation of lithium ions between the positive and negative electrodes. In cylindrical cells, the three-layer thin-film structure is wound into a cylindrical electrode assembly, while in cuboid cells, the thin-film structure is wound or stacked into an electrode assembly with a generally cuboid shape.

[0091] The positive electrode is one of the core components in a pouch battery that carries the positive active material. During charging, metal ions (e.g., lithium ions) are released from the crystal lattice of the positive active material (oxidation reaction), migrate through the electrolyte, and embed into the negative electrode. During discharging, metal ions (e.g., lithium ions in a lithium battery) are released from the negative electrode and embed into the crystal lattice of the positive active material (reduction reaction), thus achieving the storage and release of lithium ions. The positive electrode generally includes a positive current collector and a positive active material layer. The positive active material layer is coated on at least one surface of the positive current collector and includes: a positive active material, a conductive agent, and a binder. The positive active material includes, but is not limited to, at least one of the following: lithium phosphates, lithium transition metal oxides and their respective modified compounds, or other conventional materials that can be used as positive active materials for batteries. These positive active materials can be used alone or in combination. The lithium-containing phosphates include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also known as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, and lithium manganese iron phosphate and carbon composites. Lithium transition metal oxides include, but are not limited to, lithium cobalt oxides (such as LiCoO2), lithium nickel oxides (such as LiNiO2), lithium manganese oxides (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, and lithium nickel cobalt manganese oxides (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM523), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM811), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05At least one of O2 and its modified compounds. The positive electrode conductive agent includes, but is not limited to, one or more combinations of graphite, superconducting carbon, carbon black (such as acetylene black, Ketjen black, SuperP, etc.), carbon nanotubes, graphene, and carbon nanofibers. The positive electrode binder includes, but is not limited to, one or more combinations of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, fluorinated acrylate resin, styrene-butadiene rubber, polyacrylic acid, sodium polyacrylate, polyacrylamide, polyvinyl alcohol, sodium alginate, polymethacrylic acid, carboxymethyl chitosan, etc.

[0092] The definition and function of the negative electrode are as follows: During battery charging, active ions (such as Li) from the positive electrode are embedded in the negative electrode, while electrons from the positive electrode are transferred to the negative electrode through an external circuit, maintaining charge balance; during discharge, the active ions (such as Li) previously embedded in the negative electrode can be released, while electrons from the negative electrode are transferred to the negative electrode through an external circuit, maintaining charge balance; thus achieving energy storage and release. The materials and composition of the negative electrode are as follows: The negative electrode includes a negative current collector and a negative active layer disposed on at least one surface of the negative current collector. The negative current collector is a conductive metal foil, which can be made of stainless steel (including ordinary stainless steel and coated stainless steel (such as silver-plated stainless steel)), copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc. Composite current collectors may include a polymer base layer and a metal layer. Composite current collectors can be formed by depositing metallic materials (aluminum, aluminum alloys, copper, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) onto a polymer substrate (such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.). The negative electrode active layer includes the negative electrode active material, conductive agent, and binder. The negative electrode active material can be carbon-based materials such as graphite, porous carbon, hard carbon, soft carbon, and mesophase carbon microspheres, or silicon-based materials such as elemental silicon, silicon oxides, silicon-carbon composites, and silicon-nitrogen composites. The conductive agent can be conductive carbon black, carbon nanotubes, etc., and the binder can be styrene-butadiene rubber, polyacrylic acid, etc.

[0093] The diaphragm is defined and functions as follows: It is positioned between the positive and negative electrode plates to separate them and prevent short circuits. The diaphragm can be made of at least one of the following materials: glass fiber, non-woven fabric, polyethylene (PE), polypropylene (PP), and polyvinylidene fluoride (PVDF). A coating can also be applied to the diaphragm surface. This coating can be inorganic or organic. Inorganic coating materials include at least one of alumina, silicon dioxide, titanium dioxide, magnesium oxide, zirconium oxide, and boehmite; organic coatings include at least one of aramid coatings and polyvinylidene fluoride (PVDF) coatings.

[0094] The definition and function of electrolyte are: a liquid electrolyte that transports active ions. It is a liquid material that conducts ions while isolating electrons. The materials and composition of electrolyte are: electrolyte consists of solvents, electrolyte salts, additives, and other chemical substances; solvents can be carbonates, carboxylic acid esters, or ethers, etc.; electrolyte salts can be lithium salts, sodium salts, or zinc salts; additives can be vinylene carbonate, fluoroethylene carbonate, propylene sulfite, vinyl sulfite, etc.

[0095] In this embodiment, the positive electrode sheet of the soft-pack battery 10 is prepared as follows: the positive electrode active material, the conductive agent acetylene black, and the binder polyvinylidene fluoride (PVDF) are mixed, and the solvent N-methyl-2-Pyrrolidone (NMP) is added. The mixture is stirred under vacuum until the system is homogeneous to obtain a positive electrode slurry. The positive electrode slurry is uniformly coated on both surfaces of the positive electrode current collector aluminum foil, dried at room temperature, and then transferred to an oven for further drying. Finally, the positive electrode sheet is obtained by cold pressing and slitting. Specifically, the mass ratio of positive electrode active material: conductive agent: binder satisfies (92~98):(4~1):(4~1).

[0096] In this embodiment, the negative electrode sheet of the soft-pack battery 10 is prepared as follows: The negative electrode active material, conductive agent acetylene black, thickener carboxymethyl cellulose (CMC), and binder styrene-butadiene rubber (SBR) are mixed, and deionized water is added as a solvent. The mixture is stirred under vacuum until the system is homogeneous to obtain a negative electrode slurry. The negative electrode slurry is uniformly coated on both surfaces of the negative electrode current collector copper foil, dried at room temperature, and then transferred to an oven for further drying. After cold pressing and slitting, the negative electrode sheet is obtained. The ratio of negative electrode active material: conductive agent: thickener: binder satisfies (90~96): (4~2): (2~1): (4~1).

[0097] In this embodiment, the electrolyte of the soft-pack battery 10 is prepared by mixing ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) in a volume ratio of 1:1:1 to obtain an organic solvent. Then, fully dried lithium salt LiPF6 is dissolved in the mixed organic solvent to prepare an electrolyte with a concentration of 1 mol / L.

[0098] In this embodiment, the separator of the pouch cell 10 is selected from polyethylene film.

[0099] In this embodiment, the pouch battery 10 is prepared as follows: the positive electrode sheet, separator, and negative electrode sheet are stacked in sequence to form a bare battery cell. The bare cell is placed in a pouch battery casing. The casing is made of aluminum-plastic film. The first inner insulating layer of the aluminum-plastic film casing is made of cast polypropylene film (CPP), the second metal layer is made of aluminum, and the third outer insulating layer is made of polycaprolactam (nylon 6). The battery is dried, electrolyte is injected, and then packaged, allowed to stand, formed, and capacitively adjusted to obtain the pouch battery. The positive electrode active material can be selected from one or more lithium-containing positive electrode active materials, including lithium iron phosphate, ternary materials containing nickel, cobalt, and manganese, and lithium manganese iron phosphate. The negative electrode active material can be selected from one or more negative electrode active materials, including artificial graphite, natural graphite, silicon carbide, silicon oxide, and lithium titanate.

[0100] In this embodiment, the assembly method of the soft-pack battery 10 is as follows: multiple soft-pack batteries 10 are connected in series or in parallel through connecting pieces 20, the current output terminal 12 of the soft-pack battery 10 is welded to the connecting piece 20, the stacking direction is the large side direction of the soft-pack battery 10, and they are assembled into a soft-pack battery pack.

[0101] By applying the technical solution of this embodiment, the proportion of batteries with sealed pouch cell casings can be reduced, and the maximum charging temperature of the battery pack can be optimized. The specific testing process is as follows:

[0102] I. Test method for the proportion of pouch battery cells with casing seal failure:

[0103] According to the above battery preparation method, for each embodiment and comparative example, corresponding pouch batteries were prepared. Twenty pouch batteries were connected in series to form a pouch battery pack. Five identical pouch battery packs were prepared as test samples, that is, 100 pouch batteries were tested, and other test conditions remained the same.

[0104] Place each pouch battery pack at room temperature (20°C) until thermal equilibrium is reached. At room temperature, discharge the pouch battery packs to the lower limit voltage using a constant current of 0.33C. Charge them to the upper limit voltage using a constant current of 0.33C, then charge them again using a constant voltage of 0.33C until the current drops to 0.05C. After resting for 30 minutes, discharge the pouch battery packs to the lower limit voltage using a constant current of 0.33C. This constitutes one cycle. After 800 cycles, disassemble each pouch battery pack and observe the seal between the pouch battery casing and the current output terminal. Seal failure is manifested as the seal between the battery casing and the current output terminal separating or cracking, or electrolyte leakage. Record the number of pouch batteries with seal failure. The percentage of pouch battery packs with seal failure = (number of pouch batteries with seal failure / 100) 100%. A battery with a casing seal failure rate greater than 5% is considered unqualified; a rate less than or equal to 5% but greater than 2% is considered qualified; and a rate less than or equal to 2% is considered good.

[0105] When the positive electrode active material of a pouch battery is a nickel-cobalt-manganese ternary lithium battery, the upper limit voltage of the pouch battery pack is 4.25V. 12 = 85V, lower limit voltage is 2.5V. 12 = 50V; When the positive electrode active material of the pouch battery is lithium iron phosphate, the upper limit voltage of the pouch battery pack is 3.6V. 12 = 72V, lower limit voltage is 2.5V. 12 = 50V.

[0106] In this test, the active material for the positive electrode of the pouch battery was selected from a nickel-cobalt-manganese ternary LiNi alloy. 0.6 Co 0.2 Mn 0.2 Taking O2 as an example, the mass ratio of positive electrode active material: conductive agent: binder meets 96:2:2; the negative electrode active material is selected from artificial graphite, and the ratio of negative electrode active material: conductive agent: thickener: binder meets 95:2:1:2.

[0107] II. Test method for the highest charging temperature of the battery pack:

[0108] Following the battery fabrication method described above, corresponding pouch cells were prepared for each embodiment and comparative example, with the cell size remaining consistent across all pouch cells. Twelve pouch cells were connected in series to form a pouch cell pack. Temperature sensors were installed at the center of the outermost two pouch cells on their large side faces outwards from the pack, meaning a total of two temperature sensors were used per pack to record the pouch cell temperature in real time. The battery temperature was calculated as the average of the temperatures measured by the two temperature sensors.

[0109] All other test conditions remained consistent. The pouch battery pack was placed at room temperature (20°C) until thermal equilibrium was reached, and then charged at a constant current rate of 4C until the battery voltage reached its upper limit. Subsequently, constant voltage charging was switched until the battery current dropped to 0.05C. The battery temperature change was recorded throughout the charging process. If the highest battery temperature T was less than or equal to 45°C, the test result was considered good; if the highest battery temperature T was greater than 45°C but less than or equal to 60°C, the test result was considered qualified; if the highest battery temperature T was greater than 60°C, the test result was considered unqualified.

[0110] When the positive electrode active material of a pouch battery is a nickel-cobalt-manganese ternary lithium battery, the upper limit voltage of the pouch battery pack is 4.25V. 12 = 51V, lower limit voltage is 2.5V. 12 = 30V; When the positive electrode active material of the pouch battery is lithium iron phosphate, the upper limit voltage of the pouch battery pack is 3.6V. 12 = 43.2V, lower limit voltage is 2.5V 12 = 30V.

[0111] In this test, the active material for the positive electrode of the pouch battery was selected from a nickel-cobalt-manganese ternary LiNi alloy. 0.6 Co 0.2 Mn 0.2 Taking O2 as an example, the mass ratio of positive electrode active material: conductive agent: binder meets 96:2:2; the negative electrode active material is selected from artificial graphite, and the ratio of negative electrode active material: conductive agent: thickener: binder meets 95:2:1:2.

[0112] III. Test Result Comparison Table:

[0113]

[0114] In this embodiment, the casing 11 of the pouch battery 10 is an aluminum-plastic packaging film. The characteristics of the aluminum-plastic packaging film enable the pouch battery to be formed using a heat-sealing process. The aluminum-plastic packaging film, or simply aluminum-plastic film, is a multilayer film composed of an outer nylon layer (ON), an adhesive, an intermediate aluminum foil layer (Al), an adhesive, and an inner heat-sealing layer (CPP). It is the encapsulation material for the pouch battery. The nylon layer is responsible for maintaining the shape stability of the aluminum-plastic film, ensuring that the film does not deform during the lithium-ion battery manufacturing process. The Al layer, or metallic aluminum layer, primarily functions to prevent water penetration. Because lithium-ion batteries are extremely sensitive to moisture, the electrode sheet moisture content is typically required to reach the PPM level. Therefore, the packaging film must effectively block the intrusion of moisture. Nylon itself is not waterproof and cannot meet this requirement. However, metallic aluminum reacts with oxygen in the air to form a dense oxide film, thereby preventing moisture penetration and protecting the inside of the battery cell. Furthermore, the Al layer provides the necessary plasticity during the aluminum-plastic film forming process to meet the requirements of the perforation process. The PP layer, or polypropylene layer, has the property of melting at high temperatures and being adhesive. The thermal sealing process of pouch batteries mainly relies on the PP layer melting and bonding together when the end caps are heated, followed by curing and bonding during cooling. Pouch cells utilize the PP layer of the aluminum-plastic film to melt and bond at high temperatures, achieving waterproofing and fixation of the cell through encapsulation technology.

[0115] Different punching methods are chosen depending on the cell thickness. Thinner cells typically have a single punch, while thicker cells often have a double punch. This is because excessive deformation on one side can exceed the deformation limit of the aluminum-plastic film, leading to breakage. Sometimes, to meet specific design requirements, an additional small punch is made at the air pocket location to increase its capacity. The top-side sealing process is the first critical step in the production of soft-pack lithium-ion cells. It actually encompasses two sub-processes: top sealing and side sealing. During operation, the wound cell is placed into the pre-punched hole, and then the packaging film is folded in half. Heating is used to bond the aluminum-plastic film, sealing the tabs and ensuring cell quality.

[0116] Aluminum-plastic composite (APC) film for batteries possesses the following characteristics: extremely high barrier properties, excellent heat-sealing performance, resistance to electrolytes and strong acid corrosion, and good ductility, flexibility, and mechanical strength. The main components of APC film are three layers: ON / AL / CPP, bonded together with an adhesive. Depending on the lamination process, APC film can be divided into dry and hot processes. The dry process involves bonding aluminum and polypropylene with an adhesive and then directly pressing them together. The hot process involves bonding aluminum and polypropylene with MPP and hot-pressing them together under slow heating and pressure. The main advantages of the dry process are good deep-drawing results, good appearance consistency, and less susceptibility to defects such as pinholes, fisheyes, and impurities; however, its electrolyte resistance is relatively poor. The hot process can improve the adhesion between the Al and PP layers, greatly enhancing the inner surface's ability to prevent electrolyte swelling and detachment. However, this specially treated MPP requires a high temperature to melt and achieve its bonding effect. After cooling, due to the significant difference in shrinkage coefficient between MPP and PP, it is prone to inward curling.

[0117] In the description of this invention, it should be understood that "a plurality of" means two or more. Directional terms such as "front, back, up, down, left, right," "horizontal, vertical, perpendicular, horizontal," and "top, bottom" indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. These terms are used solely for the convenience of describing the invention and simplifying the description. Unless otherwise stated, these directional terms 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 limiting the scope of protection of this invention. The directional terms "inner" and "outer" refer to the inner or outer contours relative to the outline of each component itself.

[0118] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0119] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0120] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A battery pack, characterized in that, include: Multiple pouch batteries (10), each pouch battery (10) includes a cell, a casing (11) and a current output terminal (12). The cell is disposed inside the casing (11). The current output terminal (12) is bonded to and sealed to the casing (11). The first end of the current output terminal (12) is electrically connected to the cell. The connection between the first end of the current output terminal (12) and the cell forms the outer edge (124) of the current output terminal (12). The second end of the current output terminal (12) is led out to the outside of the casing (11). The connecting piece (20) is electrically connected to the current output terminals (12) of at least two of the pouch cells (10). The current output terminals (12) are welded to the connecting piece (20) to form a first welding area. The resistivity of the connecting piece (20) is less than that of the current output terminals (12). Wherein, along the lead-out direction of the current output terminal, the length between the outer edge (124) of the first end of the current output terminal (12) and the first welding area along the current transmission direction forms an overcurrent length Amm, the resistivity of the connecting piece (20) is TΩ*mm² / m, the thickness of any current output terminal (12) is Dmm, the overcurrent length Amm, the resistivity TΩ*mm² / m of the connecting piece (20) and the thickness Dmm of the current output terminal (12) satisfy: 0.6≤A*T / D≤24.04; the overcurrent length Amm satisfies: 25mm≤Amm≤100mm; the resistivity TΩ*mm² / m of the connecting piece (20) satisfies: 1.71*10 -2 Ω*mm² / m≤TΩ*mm² / m≤6*10 -2 Ω*mm² / m; The thickness Dmm of the current output terminal (12) satisfies: 0.2mm≤Dmm≤0.8mm.

2. The battery pack according to claim 1, characterized in that, The first welding area includes a first welding line (31) and a second welding line (32) arranged at intervals.

3. The battery pack according to claim 2, characterized in that, A first gap distance L1mm is formed between the first bonding wire (31) and the second bonding wire (32), and the first gap distance L1mm satisfies: 1.0mm≤L1mm≤10.0mm.

4. The battery pack according to claim 1, characterized in that, Multiple soft-pack batteries (10) are arranged along a preset direction, and the length direction of the first welding area is set perpendicular to the preset direction.

5. The battery pack according to claim 4, characterized in that, The current output terminal (12) has two side edges (121) spaced apart along the length direction of the first welding area. In the length direction of the first welding area, the first welding area is spaced apart from at least one side edge (121) of the current output terminal (12).

6. The battery pack according to claim 5, characterized in that, Along the length of the first welding area, a second gap distance L2mm is formed between the first welding area and the side edge (121) of the current output terminal (12), and the second gap distance L2mm satisfies: 2.0mm≤L2mm≤15.0mm.

7. The battery pack according to claim 5, characterized in that, The end of the connecting piece (20) along the length direction of the first welding area protrudes from at least one side edge (121) of the current output terminal (12).

8. The battery pack according to claim 7, characterized in that, The distance by which the end of the connecting piece (20) protrudes from the side edge (121) of the current output terminal (12) along the length direction of the first welding area is a protrusion distance L3mm, and the protrusion distance L3mm satisfies: 5.0mm≤L3mm≤50.0mm.

9. The battery pack according to claim 7, characterized in that, The battery pack also includes a signal acquisition terminal, which is welded to the connecting piece (20) to form a second welding area. The second welding area and the first welding area are spaced apart along the length of the first welding area.

10. The battery pack according to any one of claims 1 to 9, characterized in that, The connecting piece (20) is electrically connected to the current output terminals (12) of the two pouch cells (10). The current output terminals (12) of the two pouch cells (10) electrically connected to the connecting piece (20) at least partially overlap. The first welding area forms a weld seam in the part where the current output terminals (12) of the two pouch cells (10) at least partially overlap. The weld seam penetrates the current output terminals (12) of the two pouch cells (10) along the thickness direction of the current output terminals (12).

11. The battery pack according to claim 10, characterized in that, The first welding area has a first length L4mm along its length direction, and the first length L4mm satisfies: 30mm≤L4m≤90mm.

12. The battery pack according to claim 10, characterized in that, The plurality of the pouch cells (10) are arranged along a preset direction, and the first welding area includes a first welding line (31) and a second welding line (32) spaced apart along the preset direction.

13. The battery pack according to claim 12, characterized in that, The first weld line (31) has a first width W1mm perpendicular to the length direction of the first weld area, wherein the first width W1mm satisfies: W1mm ≥ 0.3mm; and / or, The second weld line (32) has a second width W2mm perpendicular to the length direction of the first weld area, and the second width W2mm satisfies: W2mm≥0.3mm.

14. The battery pack according to any one of claims 1 to 9, characterized in that, The connecting piece (20) is electrically connected to the current output terminals (12) of the two soft-pack batteries (10), and the current output terminals (12) of the two soft-pack batteries (10) respectively form two spaced first welding areas with the connecting piece.

15. The battery pack according to claim 14, characterized in that, The overcurrent length Amm, the resistivity TΩ*mm² / m of the connecting piece (20), and the thickness Dmm of the current output terminal (12) satisfy: 0.6≤A*T / D≤22.

0.

16. The battery pack according to any one of claims 1 to 9, characterized in that, The battery pack also includes an insulating wire harness plate (40) disposed on one side of the soft-pack battery (10), the connecting piece (20) is fixedly disposed on the insulating wire harness plate (40), the insulating wire harness plate (40) is provided with a through hole, the current output terminal (12) is at least partially disposed in the through hole, and the second end of the current output terminal (12) is connected to the side of the connecting piece (20) away from the soft-pack battery (10).

17. The battery pack according to claim 16, characterized in that, The thickness Dmm of the current output terminal (12) satisfies: 0.2mm≤Dmm≤0.7mm.

18. The battery pack according to claim 16, characterized in that, Multiple pouch batteries (10) are arranged along a preset direction. The through holes include a first through hole (41) and a second through hole (42) spaced apart on the insulating wire harness plate (40) along the preset direction. The connecting piece (20) is electrically connected to the current output terminals (12) of the two pouch batteries (10). The current output terminals (12) of the two pouch batteries (10) pass through the first through hole (41) and the second through hole (42) respectively.

19. The battery pack according to claim 18, characterized in that, The first through hole (41) is located on one side of the connecting piece (20) along the preset direction. The first through hole (41) has a first sidewall (411) and a second sidewall (412) spaced apart along the preset direction. The first sidewall (411) is located close to the connecting piece (20), and the second sidewall (412) is located away from the connecting piece (20). The second sidewall (412) and the connecting piece (20) have a first minimum preset distance L5mm along the preset direction. The first minimum preset distance L5mm satisfies: 3.0mm≤L5mm≤10.0mm.

20. The battery pack according to claim 16, characterized in that, The current output terminal (12) includes a first output segment (122) and a second output segment (123) connected at an angle to the first output segment (122). The first output segment (122) is connected to the battery cell, and the second output segment (123) is connected to the connecting piece (20). A bending area is formed between the first output segment (122) and the second output segment (123). The bending area has a second minimum preset distance L6mm between it and the first welding area, and a third minimum preset distance L7mm between it and the outer edge (124). The second minimum preset distance L6mm is smaller than the third minimum preset distance L7mm.

21. The battery pack according to any one of claims 1 to 9, characterized in that, The sum of the thicknesses of the current output terminals (12) of at least two of the pouch cells (10) electrically connected to the connecting piece (20) is less than the thickness of the connecting piece (20).

22. The battery pack according to any one of claims 1 to 9, characterized in that, The connecting piece (20) is made of copper or copper alloy, and the current output terminal (12) is made of nickel or nickel alloy.

23. The battery pack according to claim 22, characterized in that, The current output terminal (12) includes a first metal layer and a second metal layer disposed outside the first metal layer, wherein the second metal layer is nickel or a nickel alloy.

24. The battery pack according to claim 23, characterized in that, The conductivity of the first metal layer is greater than that of the second metal layer.

25. The battery pack according to any one of claims 1 to 9, characterized in that, The housing (11) includes a housing body (111) and a housing sealing layer (112) disposed on one side of the housing body (111). The battery cell is disposed inside the housing body (111). The first end of the current output terminal (12) extends into the housing body (111). The current output terminal (12) is led out from inside the housing sealing layer (112), and the current output terminal (12) is bonded and sealed to the housing sealing layer (112). The direction perpendicular to the lead-out direction of the current output terminal (12) is the second direction. The current output terminal (12) has a third width W3mm along the second direction. The housing sealing layer (112) has a fourth width W4mm along the second direction. The relationship between the third width W3mm and the fourth width W4mm satisfies: W3 / W4≤0.

7.

26. The battery pack according to any one of claims 1 to 9, characterized in that, The housing (11) includes a housing body (111) and a housing sealing layer (112) disposed on one side of the housing body (111). The battery cell is disposed inside the housing body (111). The first end of the current output terminal (12) extends into the housing body (111). The current output terminal (12) is led out from inside the housing sealing layer (112). The current output terminal (12) is bonded and sealed to the housing sealing layer (112). The current output terminal (12) has a sheet-like structure. The housing sealing layer (112) has a first end and a second end spaced apart along the lead-out direction of the current output terminal (12). The first end of the housing sealing layer (112) is located close to the housing body (111), and the second end of the housing sealing layer (112) is located away from the housing body (111). The end face of the first end of the current output terminal (12) protrudes from the end face of the first end of the housing sealing layer (112) in the direction toward the battery cell.

27. The battery pack according to claim 26, characterized in that, The distance between the end face of the first end of the current output terminal (12) and the end face of the first end of the housing sealing layer (112) is the fourth minimum preset distance, which is greater than or equal to 0.5 mm and less than or equal to 4.0 mm.

28. The battery pack according to claim 26, characterized in that, The current output terminal (12) includes a tab and an electrode plate. The tab is electrically connected to the battery cell, and the electrode plate is directly connected to the tab. The overcurrent length Amm satisfies: 30mm≤Amm≤100mm.

29. The battery pack according to claim 26, characterized in that, The battery pack also includes an adapter plate. The current output terminal (12) includes a tab and an electrode plate. The tab is electrically connected to the battery cell. The electrode plate is electrically connected to the tab through the adapter plate. The thickness Dmm of the current output terminal (12) satisfies: 0.3mm≤Dmm≤0.8mm.

30. An electrical device comprising a battery pack, characterized in that, The battery pack is the battery pack according to any one of claims 1 to 29.

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