Battery device, electric device, and energy storage device

Abstract

The application provides a battery device, an electric device and an energy storage device. The battery device comprises a box body and a soft package battery monomer. The box body comprises a support plate. The soft package battery monomer comprises a first surface and a second surface, a plurality of first surfaces are oppositely arranged along a first direction, and the support plate is oppositely arranged with a plurality of second surfaces along a second direction. The soft package battery monomer comprises a packaging bag, an electrode assembly, a negative electrode terminal and a first insulating piece. The electrode assembly comprises a negative electrode sheet, the negative electrode sheet comprises a negative electrode current collector and a negative electrode film layer, the negative electrode terminal is connected to the negative electrode current collector, the first insulating piece is arranged between the negative electrode terminal and the packaging bag, the first insulating piece is sealingly connected with the packaging bag and forms a first connecting part, the negative electrode film layer comprises a negative electrode active material, the volume distribution particle size Dv50 of the negative electrode active material is 9-17 mu m, the volume distribution particle size Dv10 of the negative electrode active material is 3-9 mu m, and the size of the first connecting part along a third direction is 2-6 mm.

Description

[0001] This application claims priority to PCT International Application PCT / CN2025 / 129813, filed on October 24, 2025, entitled “Battery Devices, Electrical Devices and Energy Storage Devices”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of battery technology, and more specifically, to a battery device, an electrical device, and an energy storage device. Background Technology

[0003] Battery devices are widely used in electronic devices such as mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and power tools, etc.

[0004] To improve the energy density of battery devices, pouch cells can be used. However, during use, pouch cells are prone to seal failure, reducing the reliability of the battery device. Summary of the Invention

[0005] This application provides battery devices, power consumption devices, and energy storage devices that can balance energy density and reliability.

[0006] In a first aspect, embodiments of this application provide a battery device, which includes a housing, a plurality of pouch battery cells, and at least one connecting beam. The housing includes a support plate and a frame disposed around the outer periphery of the support plate, the support plate being fixedly connected to the frame. The plurality of pouch battery cells are stacked and housed in the housing in a first direction, each pouch battery cell having a rated capacity greater than or equal to 50 Ah and less than or equal to 300 Ah. The surface of each pouch battery cell includes a first surface and a second surface. The first surfaces of the plurality of pouch battery cells are disposed opposite each other along the first direction, and the support plate and the plurality of second surfaces are disposed opposite each other along a second direction. The area of ​​the first surface is greater than the area of ​​the second surface. At least one pouch battery cell abuts against the connecting beam along the first direction, the connecting beam extending along a third direction, and at least one of the support plate and the frame being fixedly connected to the connecting beam. The first direction, the second direction, and the third direction are perpendicular to each other.

[0007] A single soft-pack battery cell includes a packaging bag, an electrode assembly, a negative terminal, and a first insulating component. The electrode assembly is housed within the packaging bag and includes a positive electrode sheet and a negative electrode sheet. The positive electrode sheet includes a positive current collector and a positive electrode film layer. At least one side of the positive current collector has a positive electrode film layer, which includes a positive active material comprising lithium transition metal phosphate particles. The negative electrode sheet includes a negative current collector and a negative electrode film layer. At least one side of the negative current collector has a negative electrode film layer, and the areal density of the negative electrode film layer is 8.4 mg / cm³. 2-11.7mg / cm 2 The thickness of the negative electrode film is 50μm-90μm. One end of the negative electrode is located inside the packaging bag, and the other end is located outside the packaging bag. The negative electrode is connected to the negative electrode current collector. The first insulating member surrounds the negative electrode and is disposed between the negative electrode and the packaging bag. The first insulating member is sealed to the packaging bag and forms a first connection part. The first connection part is located on one side of the electrode assembly along the third direction. The negative electrode film includes a negative electrode active material, which includes graphite. The volume distribution particle size Dv50 of the negative electrode active material is 9μm-17μm, and the volume distribution particle size Dv10 of the negative electrode active material is 3μm-9μm. The size of the first connection part along the third direction is 2mm-6mm.

[0008] In this embodiment, the pouch battery cell has advantages such as light weight, flexible design, and high energy density. Using pouch battery cells is beneficial for improving the energy density of the battery device. A rated capacity of 50Ah or greater for each pouch battery cell is beneficial for improving the energy density of the battery device; a rated capacity of 300Ah or less for each pouch battery cell is beneficial for reducing the current during charging and discharging, thus reducing heat generation. The connecting beam is fixedly connected to at least one of the support plate and the frame, which is beneficial for improving the overall strength and rigidity of the battery device and enhancing its reliability. The connecting beam and the pouch battery cell are arranged along a first direction, and the area of ​​the first surface is relatively large. Therefore, the connecting beam can constrain the expansion of the pouch battery cell, reduce its deformation, and improve its cycle performance. Using the connecting beam to constrain the pouch battery cell helps reduce the number of internal components, achieve a module-less design for the battery device, improve space utilization, and further enhance the energy density of the battery device.

[0009] In this embodiment, the areal density of the negative electrode film is set to 8.4 mg / cm³. 2 -11.7 mg / cm 2 Setting the thickness of the negative electrode film to 50μm-90μm can give the negative electrode film a larger areal density and thickness, which is beneficial to improving the energy density of the soft-pack battery cell and the energy density of the battery device.

[0010] In this embodiment, the volume distribution particle size Dv50 of the negative electrode active material is set to be less than or equal to 17 μm, and the volume distribution particle size Dv10 is set to be less than or equal to 9 μm. This is beneficial for shortening the ion intercalation path, reducing the internal resistance of the pouch cell, reducing heat generation, lowering the temperature rise of the pouch cell, and reducing the heat conducted to the first connection portion. In this embodiment, the volume distribution particle size Dv50 of the negative electrode active material is set to be greater than or equal to 9 μm, and the volume distribution particle size Dv10 is set to be greater than or equal to 3 μm. This can reduce the content of negative electrode active material with a particle size less than 9 μm, especially reducing the content of negative electrode active material with a particle size less than 3 μm. This is beneficial for reducing the active sites of the negative electrode active material, reducing the specific surface area of ​​the negative electrode active material, reducing the decomposition and gas generation of the electrolyte, reducing the internal pressure of the pouch cell during cycling, and reducing the force on the first connection portion. In this embodiment, the volume distribution particle size Dv50 of the negative electrode active material is set to 9μm-17μm, and the volume distribution particle size Dv10 is set to 3μm-9μm. This is beneficial for balancing the internal heat and gas generation of the pouch cell, balancing the force and heat effects on the first connection part, improving the cycle performance of the pouch cell, and increasing its cycle life. In this embodiment, the dimension of the first connection part along a third direction is set to be greater than or equal to 2mm, which can improve the sealing strength. Therefore, when Dv50 is 9μm-17μm and Dv10 is 3μm-9μm, the problem of sealing failure near the first connection part of the pouch cell is reduced, improving the reliability of the battery device.

[0011] In this embodiment, the dimension of the first connecting part along the third direction is set to be less than or equal to 6mm. This can reduce the space occupied by the first connecting part in the third direction, improve space utilization, increase the energy density of the battery device, shorten the conductive path of the electrode terminals, reduce the internal resistance of the soft-pack battery cell, and improve the cycle life of the soft-pack battery cell and the battery device.

[0012] In this embodiment, the volume distribution particle size Dv50 of the negative electrode active material is set to 9μm-17μm, the volume distribution particle size Dv10 of the negative electrode active material is set to 3μm-9μm, and the size of the first connecting part along the third direction is set to 2mm-6mm, which is beneficial to balance the reliability, cycle life and energy density of the battery device to a certain extent.

[0013] In some embodiments, the volume distribution particle size Dv50 of the negative electrode active material is 11μm-15μm, and the volume distribution particle size Dv10 of the negative electrode active material is 5μm-7μm, which is beneficial to improving the reliability and cycle life of the soft-pack battery cell and battery device.

[0014] In some embodiments, the pouch cell further includes an electrolyte contained in a packaging bag, and an electrolyte additive, including vinylene carbonate, wherein the mass percentage of vinylene carbonate in the electrolyte is 0.5%-5%. Adding vinylene carbonate to the electrolyte helps improve the density and uniformity of the solid electrolyte interphase (SEI) film formed on the surface of the negative electrode, reduces electrolyte decomposition and side reactions, lowers the risk of pouch cell sealing failure, and improves the cycle life and reliability of the pouch cell.

[0015] In some embodiments, the pouch cell further includes an electrolyte contained in a packaging bag, the electrolyte comprising a chain ester solvent, the chain ester solvent comprising 40% to 60% by mass in the electrolyte.

[0016] In this embodiment, the mass ratio of chain ester solvent in the electrolyte is set to be greater than or equal to 40%, which makes the electrolyte conductivity relatively high, which is beneficial to improving the liquid phase transport capability of active ions, improving the fast charging and discharging capability of the pouch battery cell, and thus improving the rate performance of the pouch battery cell; the electrolyte system has relatively low viscosity, making it easier to flow, which can improve the uniformity of electrolyte distribution and improve the cycle life of the pouch battery cell.

[0017] In this embodiment, the mass percentage of the chain ester solvent in the electrolyte is set to be less than or equal to 60% to reduce the decomposition and gas generation of the chain ester solvent during the cycling process of the pouch cell, reduce the internal pressure of the pouch cell, reduce the probability of encapsulation failure near the first connection part, and further improve the reliability of the battery device.

[0018] In some embodiments, the pouch battery cell further includes an electrolyte contained in a packaging bag, the electrolyte including dimethyl carbonate, the dimethyl carbonate comprising 10% to 40% by mass in the electrolyte.

[0019] In this embodiment, the mass percentage of dimethyl carbonate in the electrolyte is set to be greater than or equal to 10%, which is beneficial for building a low-viscosity electrolyte system, improving the ionic conductivity of the electrolyte, reducing the internal resistance of the pouch cell, reducing the heat generation of the pouch cell, and improving the kinetic performance of the pouch cell. In this embodiment, the mass percentage of dimethyl carbonate in the electrolyte is set to be less than or equal to 40%, which can reduce the amount of dimethyl carbonate vaporized or decomposed during the cycling process of the pouch cell, lower the internal gas pressure of the pouch cell, reduce the force on the first connection part, and reduce the risk of sealing failure near the first connection part of the pouch cell.

[0020] In some embodiments, the positive electrode film layer includes a conductive agent, which includes carbon nanotubes, and the carbon nanotubes include one or more of single-walled carbon nanotubes, few-walled carbon nanotubes, and multi-walled carbon nanotubes.

[0021] Carbon nanotubes have a high aspect ratio, which facilitates the bonding of multiple lithium transition metal phosphate particles in the thickness direction of the positive electrode film. This forms a long-range conductive path and increases the binding force between particles, reducing local polarization and even lithium plating problems in pouch cell during cycling, thus improving the cycle life of the pouch cell. Through the binding effect, carbon nanotubes can also reduce the rebound phenomenon of large particles in the positive electrode film, further reducing the probability of contact and short circuit between the negative and positive electrode films, and reducing the amount of gas generated by electrolyte decomposition at high temperatures. This reduces the probability of encapsulation failure near the first connection part of the pouch cell, improves the cycle performance of the pouch cell, and gives the pouch cell and battery device good reliability.

[0022] In some embodiments, the mass percentage of carbon nanotubes in the positive electrode film is 0.3%-0.7%. In this embodiment, setting the mass percentage of carbon nanotubes in the positive electrode film to be greater than or equal to 0.3% can improve the cycle performance of the pouch cell. In this embodiment, setting the mass percentage of carbon nanotubes in the positive electrode film to be less than or equal to 0.7% helps reduce the risk of excessive carbon nanotube aggregation, ensuring uniform distribution of carbon nanotubes in the positive electrode film and improving the cycle performance of the pouch cell.

[0023] In some embodiments, the electrode assembly includes a separator disposed between a positive electrode and a negative electrode. The separator includes a base film, an inorganic particle layer, and an adhesive layer. The inorganic particle layer is disposed on at least one side of the base film, and the adhesive layer is disposed on the side of at least one inorganic particle layer away from the base film. The adhesive layer is a continuous porous layer comprising a vinylidene fluoride polymer. The inorganic particle layer can improve the thermal stability of the separator, reduce the shrinkage of the base film at high temperatures, and reduce the risk of thermal runaway in the pouch cell. The inorganic particle layer can improve the tensile strength and puncture resistance of the separator, and its placement can reduce the risk of short circuits, improving the reliability of the pouch cell. The separator provided in this application uses a continuous porous layer as the adhesive layer, which has a larger bonding area, resulting in a stronger and more uniform bond between the separator and the electrode. Simultaneously, the porous structure in the adhesive layer allows for both lithium-ion transport efficiency and optimal dynamic performance of the pouch cell.

[0024] In some embodiments, the vinylidene fluoride polymer includes one or more of vinylidene fluoride homopolymers and copolymers of vinylidene fluoride and hexafluoropropylene.

[0025] In some embodiments, the ratio of the thickness T2 of the negative electrode current collector to the thickness T3 of the negative electrode sheet is 3%-7%. In this embodiment, T2 / T3 is set to less than or equal to 7% to reduce the space and weight occupied by the negative electrode current collector and increase the thickness ratio of the negative electrode film in the negative electrode sheet, which is beneficial for improving the energy density of the pouch cell. In this embodiment, T2 / T3 is set to greater than or equal to 3% to give the negative electrode current collector better current-carrying capacity, reduce the internal resistance of the pouch cell, and reduce internal heat generation in the pouch cell.

[0026] In some embodiments, the negative electrode current collector includes a negative electrode current collector portion and a negative electrode tab. The negative electrode tab is located on the side of the negative electrode current collector portion closer to the negative terminal. At least a portion of the negative electrode film layer is disposed on the negative electrode current collector portion, and at least a portion of the negative electrode tab is not provided with a negative electrode film layer. Multiple negative electrode tabs are welded to the negative terminal to form a second connection portion, which is spaced apart from the first connection portion. During the charging and discharging process of the battery device, the second connection portion generates heat under the action of current. In this embodiment, the second connection portion is spaced apart from the first connection portion to reduce the heat conducted from the second connection portion to the first connection portion, reduce the temperature rise of the first connection portion during the charging and discharging process of the battery device, slow down the fatigue aging of the first connection portion, reduce the risk of sealing failure of the pouch battery cell, and improve the reliability of the battery device.

[0027] In some embodiments, the area of ​​the second connecting portion is 20 mm. 2 Up to 60 mm 2 In this embodiment, the area of ​​the second connecting part is set to be greater than or equal to 20 mm. 2 This can reduce the resistance of the second connection, improve its current-carrying capacity, reduce heat generation, lower its temperature rise, reduce the risk of electrolyte decomposition, reduce heat conducted to the first connection, slow down fatigue aging of the first connection, reduce the risk of sealing failure of the pouch cell near the first connection, and improve the cycle life of the pouch cell. In this embodiment, the area of ​​the second connection is set to be less than or equal to 60 mm². 2 This can reduce the space occupied by the second connection part, thereby reducing the size requirements of the negative electrode tab and negative terminal, and reducing the impact of increasing the area of ​​the second connection part on the energy density of the pouch cell.

[0028] In some embodiments, the first insulating member extends inward beyond the first connecting portion at its end near the negative electrode current collector in a third direction. In the third direction, the first insulating member and the second connecting portion are spaced apart. This embodiment separates the first insulating member from the second connecting portion, thereby reducing heat conduction to the first insulating member, slowing fatigue aging of the first connecting portion, reducing the risk of single-cell sealing failure in the pouch battery, and improving the reliability of the battery device.

[0029] In some embodiments, a plurality of negative tabs and negative terminals are stacked along a first direction; the pouch cell also includes a second insulating member, which is disposed on the side of the plurality of negative tabs away from the negative terminals and covers the second connection portion in the first direction. The second insulating member can cover impurities remaining on the surface of the second connection portion, reducing the risk of impurities falling into the electrode assembly and improving reliability. The second insulating member can also separate at least a portion of the second connection portion from the packaging bag, reducing the risk of the second connection portion scratching the packaging bag.

[0030] In some embodiments, the second connection portion includes a plurality of first weld portions. By providing a plurality of first weld portions, heat accumulation during welding can be reduced, heat conducted to the separator of the electrode assembly can be reduced, the risk of separator shrinkage and deformation can be reduced, and the reliability of the pouch cell can be improved.

[0031] In some embodiments, the second connecting portion includes a linear first welding portion. Using a linear first welding portion facilitates continuous welding and improves welding efficiency.

[0032] In some embodiments, multiple negative tabs are welded together to form a second welded portion. A portion of the second welded portion is welded to the negative terminal to form a second connection portion. The second connection portion is directly connected to the second welded portion, which helps to reduce the risk of the negative tabs and the second connection portion becoming disconnected, reduces the resistance between the negative tabs and the negative terminal, and reduces heat generation.

[0033] In some embodiments, the packaging bag includes a stacked encapsulation layer, a metal layer, and a protective layer. The encapsulation layer is located on the surface of the metal layer facing the electrode assembly, and the encapsulation layer is fused to a first insulating member to form a first connection. By providing a multi-layer structure, the strength and weight of the packaging bag can be balanced, thereby increasing the energy density of the pouch battery cell. The metal layer can reduce the penetration of water and oxygen into the interior of the packaging bag, reducing the decomposition of the electrolyte and the oxidation of the electrode materials, thereby improving the lifespan of the pouch battery cell. The fusion of the encapsulation layer with the first insulating member helps to improve connection strength and sealing performance.

[0034] In some embodiments, the thickness of the first insulating element is greater than the thickness of the encapsulation layer. Using an encapsulation layer with a smaller, uniform thickness is beneficial for reducing the volume and weight of the packaging bag and increasing the energy density of the individual pouch battery cells. Using a first insulating element with a larger thickness can improve the connection strength between the first insulating element and the encapsulation layer.

[0035] In some embodiments, the metal layer comprises aluminum, and the encapsulation layer and protective layer comprise resin materials.

[0036] In some embodiments, the encapsulation layer is made of polypropylene, and the protective layer is made of one or more of nylon and polyethylene terephthalate.

[0037] In some embodiments, in the second direction, the ratio of the width W2 of the negative terminal to the width W3 of the packaging bag is 0.2-0.5. In this embodiment, setting W2 / W3 to be greater than or equal to 0.2 can increase the current-carrying capacity of the negative terminal and reduce heat generation. Setting W2 / W3 to be less than or equal to 0.5 can reduce the packaging difficulty of the negative terminal, decrease the sealing interface between the first insulator and the packaging bag, and between the first insulator and the negative terminal, thus reducing the risk of seal failure. Setting W2 / W3 to 0.2-0.5 in this embodiment helps reduce the risk of seal failure in individual pouch battery cells and improves the reliability of the battery device.

[0038] In some embodiments, the dimension L0 of the pouch cell in the third direction is 500mm-1250mm; the dimension W0 of the pouch cell in the second direction is 100mm-150mm; and the dimension H0 of the pouch cell in the first direction is 14mm-22mm. Having the dimensions of the pouch cell within these ranges is beneficial for optimizing the arrangement of the pouch cells, improving space utilization, and increasing the energy density of the battery device.

[0039] In some embodiments, the electrode assembly has a stacked structure. Using an electrode assembly with a stacked structure can improve the energy density of a single pouch cell.

[0040] In some embodiments, the battery device includes a thermal management component 40, which is located on at least one side of a plurality of pouch cell cells in a second direction. The thermal management component is used to exchange heat with the pouch cell cells. The pouch cell cells transfer heat to the thermal management component, thereby dissipating heat, reducing heat accumulation inside the packaging bag, lowering the temperature rise of the pouch cell cells, reducing electrolyte decomposition and gas generation, slowing down fatigue aging of the first connection, reducing the risk of pouch cell sealing failure, and improving the reliability of the battery device.

[0041] In some embodiments, the battery device further includes a thermally conductive adhesive that adheres to the second surface and the thermal management component. The thermally conductive adhesive can bond the pouch cell to the thermal management component, improving the strength and rigidity of the battery device and enhancing the stability of the pouch cell. The thermally conductive adhesive has excellent thermal conductivity; using it to bond the second surface and the thermal management component can improve the heat transfer efficiency between the second surface and the thermal management component, enhance heat transfer stability, and thus improve the cycle performance of the pouch cell during long-term cycling.

[0042] In some embodiments, the battery device further includes a heat-conducting plate connected to the thermal management component, wherein at least a portion of the heat-conducting plate is disposed between adjacent pouch cell cells in a first direction. The heat-conducting plate can conduct heat from the pouch cell cells to the thermal management component, thereby improving heat exchange efficiency, reducing the temperature of the pouch cell cells, reducing electrolyte decomposition or vaporization, slowing fatigue aging of the first connection portion, reducing the risk of deformation or tearing of the first connection portion, and thus reducing the risk of pouch cell sealing failure. Arranging the heat-conducting plate and the pouch cell cells along the first direction enables heat exchange between the heat-conducting plate and the first surface, thereby increasing the heat exchange area and improving heat exchange efficiency.

[0043] In some embodiments, the battery device includes a plurality of heat-conducting plates arranged along a first direction, with pouch cell batteries disposed between adjacent heat-conducting plates. By providing multiple heat-conducting plates, the thermal management effect of the battery device can be improved, the temperature consistency of the pouch cell batteries can be enhanced, and the risk of pouch cell sealing failure can be reduced.

[0044] In some embodiments, the heat-conducting plate includes a first plate portion and two second plate portions arranged along a first direction. At least one pouch cell is disposed between the two second plate portions. The first plate portion connects the two second plate portions. The first plate portion and a thermal management component are arranged along a second direction. The end of the second plate portion away from the first plate portion is connected to the thermal management component. The heat-conducting plate can conduct some of the heat from the pouch cell to the thermal management component, and can also protect and constrain the pouch cell, improving the stability of the pouch cell. It reduces the movement of the pouch cell when the battery device is subjected to external impact, thereby improving the reliability and stability of the battery device.

[0045] In some embodiments, the support plate is integrally formed with the thermal management component; the support plate can serve both support and thermal management functions, which helps to reduce the number of structural components and improve the energy density of the battery device. In other embodiments, the thermal management component is located between the support plate and multiple pouch cell cells.

[0046] Secondly, embodiments of this application provide an electrical device that includes a battery device provided in any of the embodiments of the first aspect, the battery device being used to provide electrical energy.

[0047] Thirdly, embodiments of this application provide an energy storage device, namely the battery device provided in any embodiment of the first aspect, which is used to store electrical energy. Attached Figure Description

[0048] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0049] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments; Figure 2 This is a schematic diagram of the structure of an energy storage device provided in some embodiments of this application; Figure 3 Explosion-proof diagrams of battery devices provided in some embodiments of this application; Figure 4 This is an exploded view of a single pouch battery cell provided in some embodiments of this application; Figure 5 A schematic diagram of a single soft-pack battery cell provided in some embodiments of this application; Figure 6 This is a schematic diagram of the electrode assembly of a pouch cell provided in some embodiments of this application; Figure 7 for Figure 6 A cross-sectional schematic diagram of the electrode assembly shown; Figure 8 A partial cross-sectional schematic diagram of a single pouch battery cell for a battery device provided in some embodiments of this application; Figure 9 A schematic diagram of the positive electrode of a pouch cell in a battery device provided in some embodiments of this application; Figure 10 A schematic diagram of the negative electrode of a pouch cell in a battery device provided in some embodiments of this application; Figure 11 A schematic diagram of the separator of a pouch cell for a battery device provided in some embodiments of this application; Figure 12 A schematic diagram of the surface morphology of the separator of a soft-pack battery cell provided in an embodiment of this application; Figure 13 for Figure 8 Enlarged illustration within the box; Figure 14 A cross-sectional schematic diagram of the negative terminal of a pouch cell in a battery device provided in some embodiments of this application; Figure 15 A schematic diagram of a partial structure of a pouch battery cell for a battery device provided in some embodiments of this application; Figure 16Another partial cross-sectional schematic diagram of a single pouch battery cell for a battery device provided in some embodiments of this application; Figure 17 A partial cross-sectional schematic diagram of a battery device provided in some embodiments of this application; Figure 18 This is another partial cross-sectional schematic diagram of a battery device provided in some embodiments of this application.

[0050] The annotations in the attached figures are explained as follows: 1. Vehicle; 2. Battery unit; 3. Controller; 4. Motor; 5. Energy storage device; 6. Cabinet; 10. Soft-pack battery cell; 10a. First surface; 10b. Second surface; 11. Packaging bag; 111. Packaging film; 1111. Sealing edge; 11111. First sealing edge; 11112. Second sealing edge; 1112. Bottom wall; 1113. Peripheral wall; 11131. First side wall; 11132. Second side wall; 112. Receiving cavity; 11a. Sealing layer; 11b. Metal layer; 11c. Protective layer; 12. Electrode assembly; 121. Positive electrode sheet; 1211. Positive current collector; 12111. Positive electrode tab; 12112. Positive current collector section; 1212. Positive electrode film layer; 122. Negative electrode sheet; 1221. Negative current collector; 12211. Negative electrode tab; 12212. Negative current collector section; 1222. Negative electrode film layer; 123. Separator; 1231. Base film; 1232. Inorganic particle layer; 1233. Adhesive layer; 124. Second welded part; 125. Fourth welded part; 13. Negative terminal; 131. Terminal body; 132. Nickel layer; 14. First insulating component; 15. First connecting part; 16. Positive terminal; 17. Second connecting part; 171. First welding part; 18. Second insulating component; 191. Third insulating component; 192. Third connecting part; 193. Fourth connecting part; 1931. Third welding part; 194. Fourth insulating component; 20. Housing; 21. Support plate; 22. Frame; 23. Cover plate; 30. Connecting beam; 40. Thermal management components; 50. Thermally conductive adhesive; 60. Thermally conductive plate; 61. First plate section; 62. Second plate section; 70. Thermal insulation component; X, first direction; Y, third direction; Z, second direction. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0052] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0053] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0054] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0055] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0056] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0057] In this application, "multiple" means two or more (including two).

[0058] In this application, the battery cell may include a lithium-ion secondary battery cell, a lithium-ion primary battery cell, a lithium-sulfur battery cell, a sodium-lithium-ion battery cell, a sodium-ion battery cell, or a magnesium-ion battery cell, etc., and the embodiments of this application are not limited thereto. The battery cell may be cylindrical, flat, cuboid, or other shapes, etc., and the embodiments of this application are not limited thereto.

[0059] Currently, judging from market trends, the application of battery devices is becoming increasingly widespread. Battery devices are not only used in energy storage power systems such as hydropower, thermal power, wind power, and solar power plants, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in aerospace and other fields. With the continuous expansion of the application areas of battery devices, the market demand is also constantly increasing.

[0060] A battery device typically refers to a single physical module comprising multiple battery cells to provide higher voltage and capacity. A battery cell can be the smallest unit that makes up a battery device. A battery cell can be a rechargeable battery, which is a battery cell that can be recharged after discharge to activate its active materials and continue to be used.

[0061] A typical pouch cell includes a packaging bag, an electrode assembly, electrode terminals, and an insulating component. The electrode assembly is housed within the packaging bag, the electrode terminals are connected to the electrode assembly and extend out of the packaging bag, and the insulating component surrounds the electrode terminals and is disposed between the electrode terminals and the packaging bag. The insulating component is sealed to the packaging bag and forms a first connection portion.

[0062] Pouch cells offer advantages such as light weight, flexible design, and high energy density. Using pouch cells helps improve the energy density of battery devices. In this application, multiple pouch cells can be directly integrated and assembled within the battery device's housing, eliminating the need for traditional module structures, reducing redundant components, improving space utilization, and further enhancing the energy density of the battery device.

[0063] With the development of battery technology, the market has placed higher demands on the energy density of battery devices. This application can increase the areal density and thickness of the negative electrode film, which helps to reduce the space and weight occupied by the negative electrode current collector in the electrode assembly, allowing the negative electrode sheet per unit area to accommodate more active material, and further improving the energy density of the pouch cell and the energy density of the battery device.

[0064] However, compared to metal casings, packaging bags made of metal-plastic films have lower heat dissipation capabilities. The module-less design of the battery pack leads to a more compact arrangement of the individual pouch cells, further reducing their heat dissipation efficiency. Additionally, increasing the areal density and thickness of the negative electrode film also lengthens the ion transport path, increasing the internal resistance of the pouch cell and thus increasing internal heat generation. In summary, the packaging bag material, the module-less design of the battery pack, and the increased areal density and thickness of the negative electrode film all reduce the heat dissipation efficiency of the pouch cell, resulting in higher internal temperatures.

[0065] High temperatures reduce the stability of the solid electrolyte interphase (SEI) film on the surface of the negative electrode active material, leading to increased side reactions, the release of more gas, and an increase in internal gas pressure in the pouch cell. Under the influence of temperature and gas pressure, the pouch cell is prone to sealing failure near the first connection part.

[0066] In view of this, this application provides a technical solution that reduces the risk of sealing failure of individual soft-pack battery cells by reasonably designing the particle size of the negative electrode active material and the width of the first connection part, while taking into account the energy density and reliability of the battery device.

[0067] For ease of explanation, the following embodiments will use a vehicle as an example of an electrical device.

[0068] Figure 1 The diagram shows the structural features of a vehicle provided in some embodiments of this application.

[0069] like Figure 1 As shown, a battery device 2 is installed inside the vehicle 1. The battery device 2 can be located at the bottom, front, or rear of the vehicle 1. The battery device 2 can be used to power the vehicle 1; for example, the battery device 2 can serve as the operating power source for the vehicle 1.

[0070] The vehicle 1 may also include a controller 3 and a motor 4. The controller 3 is used to control the battery device 2 to supply power to the motor 4, for example, for the power needs of the vehicle 1 during starting, navigation and driving.

[0071] In some embodiments of this application, the battery device 2 can not only serve as the operating power source for the vehicle 1, but also as the driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0072] Figure 2 This is a schematic diagram of the structure of an energy storage device provided in some embodiments of this application.

[0073] Reference Figure 2This application provides an energy storage device 5, including one or more battery clusters to increase the voltage and capacity of the energy storage device 5. The battery clusters may include multiple battery devices 2, which are connected in series via a busbar to increase the voltage of the energy storage device 5. When the energy storage device 5 includes multiple battery clusters, the multiple battery clusters are connected in parallel to increase the capacity of the energy storage device 5.

[0074] The energy storage device 5 can be used in energy storage power stations, wind power generation systems, solar power generation systems, mobile power systems, or temporary power supply systems. The energy storage device 5 can store electrical energy as needed and output it when appropriate. For example, the energy storage device 5 can store electrical energy during off-peak hours and provide power to relevant users or electrical devices during peak hours.

[0075] In some embodiments, the energy storage device 5 is an energy storage container or an energy storage cabinet.

[0076] In some embodiments, the energy storage device 5 may include a cabinet 6 and one or more battery clusters, the battery clusters being housed in the cabinet 6.

[0077] In some embodiments, the energy storage device 5 may include modules such as a thermal management module, a main control module, a central control module, a power distribution module, and a fire protection module.

[0078] As an example, the thermal management module may include a liquid cooling unit that supplies coolant to each battery device 2 via pipelines for regulating the temperature of the individual pouch cells.

[0079] As an example, the main control module can serve as the battery management unit for the battery cluster, used to monitor and manage the battery cluster. The main control module can monitor information such as the current, voltage, power, or temperature of the battery cluster. For instance, it can control the charging and discharging current and voltage of the battery cluster. The main control module includes modules such as an auxiliary battery management unit (SBMU) and a fusion switch.

[0080] As an example, the central control module can serve as the battery management unit for the energy storage device 5, used to monitor and manage the energy storage device 5. The central control module can monitor information such as current, voltage, power, state of charge, or temperature of the energy storage device 5. For example, it can control the charging and discharging current and voltage of the energy storage device 5. As an example, the central control module includes modules such as an insulation monitoring module (IMM), a master battery management unit (MBMU), an Ethernet (ETH) module, and a fiber optic conversion module.

[0081] As an example, a fire protection system includes control panels, detectors, alarm devices, etc., used to detect, alarm, or extinguish fires in energy storage systems. As an example, the power distribution device can be used to distribute power to the power modules of the energy storage device 5.

[0082] Figure 3 Explosion-proof diagrams of battery devices provided in some embodiments of this application; Figure 4 This is an exploded view of a single pouch battery cell provided in some embodiments of this application; Figure 5 A schematic diagram of a single soft-pack battery cell provided in some embodiments of this application; Figure 6 This is a schematic diagram of the electrode assembly of a pouch cell provided in some embodiments of this application; Figure 7 for Figure 6 The diagram shows a cross-sectional view of the electrode assembly.

[0083] Reference Figures 3 to 7 This application provides a battery device 2, which includes a housing 20 and a plurality of pouch battery cells 10, wherein the plurality of pouch battery cells 10 are housed within the housing 20.

[0084] The pouch battery cell 10 can be a rechargeable battery cell, which refers to a pouch battery cell 10 that can be recharged after discharge to activate the active materials and continue to be used. As an example, the pouch battery cell 10 can be a lithium-ion battery cell.

[0085] Multiple pouch battery cells 10 are connected in series, parallel, or in a mixed configuration via a busbar. A mixed configuration refers to multiple pouch battery cells 10 being connected in both series and parallel configurations.

[0086] The soft-pack battery cell 10 can refer to a battery cell that uses a flexible packaging film (such as aluminum-plastic film) as its outer casing. Compared with battery cells with metal structural casings, the soft-pack battery cell 10 has the advantages of being lightweight and having a more versatile outer contour shape.

[0087] The soft-pack battery cell 10 can be rectangular, square, or other irregularly shaped.

[0088] The battery device 2 includes one or more battery cell assemblies, which include pouch cell 10 stacked in a first direction X. The battery cell assembly can be formed by directly fixing multiple pouch cell 10s to a housing 20 within the housing 20.

[0089] In some embodiments, the housing 20 includes a support plate 21 and a frame 22 disposed around the outer periphery of the support plate 21, wherein the support plate 21 and the frame 22 are fixedly connected.

[0090] The support plate 21 and the frame 22 can be integrally formed or independently formed. Optionally, the support plate 21 can be welded to the frame 22 to achieve a fixed connection between the support plate 21 and the frame 22.

[0091] The support plate 21 can be used to support the soft-pack battery cell 10.

[0092] In some embodiments, the frame 22 includes a plurality of side beams, which are connected sequentially along the circumference of the frame 22.

[0093] In some embodiments, the housing 20 further includes a cover plate 23 connected to the frame 22. The cover plate 23 and the support plate 21 are respectively connected to the frame 22, so that the interior of the housing 20 forms a closed space to accommodate the battery cell assembly.

[0094] In some embodiments, the housing 20 may be part of the vehicle's chassis structure. For example, a portion of the housing 20 may be at least a portion of the vehicle's floor, or a portion of the housing 20 may be at least a portion of the vehicle's crossbeams and longitudinal beams.

[0095] In some embodiments, the rated capacity of each pouch cell 10 is greater than or equal to 50 Ah and less than or equal to 300 Ah.

[0096] The rated capacity of the pouch cell 10 has a meaning known in the art and can be tested using methods known in the art, or obtained from the battery device instruction manual. As an example, at 25°C, the pouch cell is charged to 3.65V at a charging rate of 0.5C (the nominal capacity of the pouch cell), then charged at a constant voltage of 3.65V to 0.05C, left to stand for 10 minutes, and then discharged to 2.5V at a discharging rate of 1C, left to stand for 10 minutes. The capacity C during the discharge process is calculated using the formula C=I×t, in Ah.

[0097] As an example, the rated capacity of the pouch cell 10 is 50Ah, 80Ah, 100Ah, 120Ah, 150Ah, 180Ah, 200Ah, 220Ah, 250Ah, 280Ah, 300Ah, or any value between two of the above.

[0098] The rated capacity of each pouch cell 10 is greater than or equal to 50Ah, which is beneficial to improving the energy density of the battery device 2; the rated capacity of each pouch cell 10 is less than or equal to 300Ah, which is beneficial to reducing the current of the pouch cell 10 during charging and discharging, reducing the heat generation of the pouch cell 10, improving the cycle life of the pouch cell 10, and reducing the risk of sealing failure of the pouch cell 10.

[0099] In some embodiments, the pouch cell 10 includes a packaging bag 11 and an electrode assembly 12, the electrode assembly 12 being housed within the packaging bag 11.

[0100] In some embodiments, the packaging bag 11 includes two packaging films 111, with a receiving cavity 112 formed between the two packaging films 111, and the electrode assembly 12 is received in the receiving cavity 112.

[0101] At least one packaging film 111 is provided with a receiving recess, and the receiving cavity 112 includes the receiving recess. In some examples, only one packaging film 111 is provided with a receiving recess. In other examples, both packaging films 111 are provided with receiving recesses, the two receiving recesses are disposed opposite to each other, and the receiving cavity 112 includes two receiving recesses.

[0102] In some embodiments, the receiving recess can be formed by stamping the packaging film 111.

[0103] In some embodiments, the two packaging films 111 are integrally formed. As an example, the two packaging films 111 can be formed by folding a single aluminum-plastic film.

[0104] In some alternative embodiments, the two packaging films 111 are separate structures. As an example, the two packaging films 111 are two aluminum-plastic films.

[0105] In some embodiments, each packaging film 111 includes a sealing edge 1111 surrounding the receiving cavity 112, and the sealing edges 1111 of two packaging films 111 are stacked and connected to seal the receiving cavity 112.

[0106] In some embodiments, the sealing edges 1111 of the two packaging films 111 are welded together by hot pressing.

[0107] In some embodiments, each packaging film 111 has two first packaging edges 11111 and two second packaging edges 11112. The two first packaging edges 11111 are located on both sides of the receiving cavity 112 along the third direction Y, and the two second packaging edges 11112 are located on both sides of the receiving cavity 112 along the second direction Z. Each second packaging edge 11112 connects to the two first packaging edges 11111.

[0108] The sealing edges 1111 of two packaging films 111 are connected to form a sealing portion. The sealing portion includes two first sealing portions and two second sealing portions. The two first sealing portions are located on both sides of the receiving cavity 112 along a third direction Y, and the two second sealing portions are located on both sides of the receiving cavity 112 along a second direction Z. The first sealing portion includes a first sealing edge 11111 of one packaging film 111 and a first sealing edge 11111 of the other packaging film 111, and the two first sealing edges 11111 of the first sealing portion are at least partially fused together. The second sealing portion includes a second sealing edge 11112 of one packaging film 111 and a second sealing edge 11112 of the other packaging film 111, and the two second sealing edges 11112 of the second sealing portion are at least partially fused together.

[0109] In some embodiments, the packaging film 111 includes a bottom wall 1112 and a peripheral wall 1113. The peripheral wall 1113 is connected to the outer periphery of the bottom wall 1112, and the bottom wall 1112 and the peripheral wall 1113 enclose a receiving recess. The peripheral wall 1113 includes two first sidewalls 11131 disposed opposite each other along a third direction Y and two second sidewalls 11132 disposed opposite each other along a second direction Z. The two first sidewalls 11131 are respectively connected to two first encapsulation edges 11111, and the two second sidewalls 11132 are respectively connected to two second encapsulation edges 11112.

[0110] In some embodiments, the second encapsulation portion is bent toward and adhered to the second sidewall 11132. By bending the second encapsulation portion, the space occupied by the second encapsulation portion in the second direction Z can be reduced.

[0111] In some embodiments, the electrode assembly 12 includes a positive electrode 121 and a negative electrode 122. During the charging and discharging process of the pouch cell 10, active ions (e.g., lithium ions) are inserted and extracted back and forth between the positive electrode 121 and the negative electrode 122. The electrolyte acts as a conductor for ions between the positive electrode 121 and the negative electrode 122.

[0112] In some embodiments, the positive electrode 121 includes a positive current collector 1211 and a positive electrode film 1212, with the positive electrode film 1212 disposed on at least one side of the positive current collector 1211. As an example, the positive current collector 1211 has two surfaces opposite each other in its own thickness direction, and the positive electrode film 1212 is disposed on either or both of the two opposite surfaces of the positive current collector 1211.

[0113] As an example, the positive current collector 1211 can be a metal foil or a composite current collector. For example, as a metal foil, it can be aluminum or stainless steel with a silver surface treatment, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0114] In some embodiments, the positive electrode active material comprises lithium transition metal phosphate particles.

[0115] Lithium-containing transition metal phosphates refer to phosphate materials containing lithium and transition metal elements, and can be detected by any method known in the art. For example, they can be detected by combining X-ray diffraction (XRD) with energy dispersive spectroscopy (EDS) or inductively coupled plasma mass spectrometry (ICP-MS).

[0116] Lithium-containing transition metal phosphates, as positive electrode active materials, have advantages such as high safety, long cycle life, low cost, and high high temperature stability.

[0117] In some embodiments, the pouch cell 10 is a lithium iron phosphate battery.

[0118] In some embodiments, the negative electrode 122 includes a negative electrode current collector 1221 and a negative electrode film layer 1222, with the negative electrode film layer 1222 disposed on at least one side of the negative electrode current collector 1221. As an example, the negative electrode current collector 1221 has two surfaces opposite each other in its own thickness direction, and the negative electrode film layer 1222 is disposed on either or both of the two opposite surfaces of the negative electrode current collector 1221.

[0119] As an example, the negative electrode current collector 1221 can be made of metal foil, conductive polymer material, carbon material, or composite current collector. For example, as a metal foil, pure metal, alloy, or surface-treated metal can be used, including but not limited to stainless steel, copper, aluminum, nickel, titanium, or silver. The composite current collector may include a polymer material substrate and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0120] In some embodiments, the negative electrode film layer 1222 includes a negative electrode active material. The negative electrode active material includes graphite. As an example, the graphite may include at least one of artificial graphite and natural graphite.

[0121] In some embodiments, the negative electrode active material may further include at least one of the following materials: soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys.

[0122] In some embodiments, the positive current collector 1211 may be made of aluminum, and the negative current collector 1221 may be made of copper.

[0123] In some embodiments, the electrode assembly 12 further includes a separator 123 disposed between the positive electrode 121 and the negative electrode 122.

[0124] In some embodiments, the separator 123 is a separator membrane. This application does not impose any particular limitation on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.

[0125] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can be a single-layer film or a multi-layer composite film. When the separator is a multi-layer composite film, the materials of each layer can be the same or different. The separator 123 can be a single component located between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes. An inorganic particle coating, an organic particle coating, or an organic / inorganic composite coating can also be applied to the surface of the separator.

[0126] In some embodiments, the pouch cell 10 further includes an electrolyte that acts as a conductor of ions between the positive and negative electrodes. The electrolyte includes an electrolyte salt and a solvent.

[0127] In some embodiments, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0128] In some embodiments, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0129] In some embodiments, the electrolyte may optionally include additives. For example, additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain properties of the battery cell, such as additives that improve the overcharge / fast charge performance of the pouch cell, additives that improve the high-temperature performance of the pouch cell, and additives that improve the low-temperature performance of the pouch cell.

[0130] In some embodiments, the electrode assembly 12 can be a wound structure, a stacked structure, or a hybrid structure of wound and stacked.

[0131] In some embodiments, the electrode assembly 12 is a wound structure. The positive electrode 121 and the negative electrode 122 are wound into a wound structure.

[0132] In some embodiments, the electrode assembly 12 has a stacked structure.

[0133] As an example, multiple positive electrode plates 121 and multiple negative electrode plates 122 can be set, and multiple positive electrode plates 121 and multiple negative electrode plates 122 can be stacked alternately.

[0134] As an example, multiple positive electrode plates 121 can be provided, and multiple negative electrode plates 122 can be folded to form multiple stacked folded segments, with a positive electrode plate 121 sandwiched between adjacent folded segments.

[0135] As an example, both the positive electrode 121 and the negative electrode 122 are folded to form multiple stacked folded segments.

[0136] As an example, multiple separators 123 can be provided, respectively disposed between any adjacent positive electrode 121 or negative electrode 122.

[0137] As an example, the separator 123 can be continuously arranged and disposed between any adjacent positive electrode 121 or negative electrode 122 by means of folding or rolling.

[0138] Figure 8A partial cross-sectional schematic diagram of a single pouch battery cell for a battery device provided in some embodiments of this application; Figure 9 A schematic diagram of the positive electrode of a pouch cell in a battery device provided in some embodiments of this application; Figure 10 A schematic diagram of the negative electrode of a pouch cell in a battery device provided in some embodiments of this application; Figure 11 A schematic diagram of the separator of a pouch cell for a battery device provided in some embodiments of this application; Figure 12 This is a schematic diagram of the surface morphology of the separator of a soft-pack battery cell in an embodiment of the present application.

[0139] Reference Figures 3 to 12 This application provides a battery device 2, which includes a housing 20, a plurality of pouch battery cells 10, and at least one connecting beam 30. The housing 20 includes a support plate 21 and a frame 22 arranged around the outer periphery of the support plate 21, and the support plate 21 is fixedly connected to the frame 22. The plurality of pouch battery cells 10 are stacked in a first direction X and housed within the housing 20. The rated capacity of each pouch battery cell 10 is greater than or equal to 50Ah and less than or equal to 300Ah. The surface of the pouch battery cell 10 includes a first surface 10a and a second surface 10b. The first surfaces 10a of the plurality of pouch battery cells 10 are arranged opposite each other along the first direction X, and the support plate 21 and the plurality of second surfaces 10b are arranged opposite each other along the second direction Z. The area of ​​the first surface 10a is greater than the area of ​​the second surface 10b. At least one pouch cell 10 abuts against the connecting beam 30 along the first direction X. The connecting beam 30 extends along the third direction Y. At least one of the support plate 21 and the frame 22 is fixedly connected to the connecting beam 30. The first direction X, the second direction Z and the third direction Y are perpendicular to each other.

[0140] The pouch cell 10 includes a packaging bag 11, an electrode assembly 12, a negative terminal 13, and a first insulating member 14. The electrode assembly 12 is housed within the packaging bag 11 and includes a positive electrode 121 and a negative electrode 122. The positive electrode 121 includes a positive current collector 1211 and a positive electrode film 1212. The positive electrode film 1212 is provided on at least one side of the positive current collector 1211 and includes a positive active material, which includes lithium transition metal phosphate particles. The negative electrode 122 includes a negative current collector 1221 and a negative electrode film 1222. The negative electrode film 1222 is provided on at least one side of the negative current collector 1221 and has an areal density of 8.4 mg / cm³. 2 -11.7mg / cm 2The thickness of the negative electrode film 1222 is 50μm-90μm. One end of the negative terminal 13 is located inside the packaging bag 11, and the other end is located outside the packaging bag 11. The negative terminal 13 is connected to the negative current collector 1221. The first insulating member 14 surrounds the negative terminal 13 and is disposed between the negative terminal 13 and the packaging bag 11. The first insulating member 14 is sealed to the packaging bag 11 and forms a first connection part 15. The first connection part 15 is located on one side of the electrode assembly 12 along the third direction Y. The negative electrode film 1222 includes a negative electrode active material, which includes graphite. The volume distribution particle size Dv50 of the negative electrode active material is 9μm-17μm, and the volume distribution particle size Dv10 of the negative electrode active material is 3μm-9μm. The size of the first connection part 15 along the third direction Y is 2mm-6mm.

[0141] The surface of the pouch cell 10 includes two first surfaces 10a, which are disposed opposite to each other along a first direction X. Optionally, the thickness direction of the pouch cell 10 is parallel to the first direction X, and the first surface 10a is the surface with the largest area of ​​the pouch cell 10. Optionally, the first surface 10a is a plane.

[0142] Two first surfaces 10a are formed on two packaging films 111 respectively. As an example, both packaging films 111 are provided with receiving recesses, and the two first surfaces 10a are formed on the bottom walls 1112 of the two packaging films 111 respectively.

[0143] The first surfaces 10a of multiple pouch cell 10 are arranged along the first direction X.

[0144] The surface of the pouch cell 10 includes two second surfaces 10b, which are arranged opposite to each other along a second direction Z. As an example, in the second direction Z, one second surface 10b of the pouch cell 10 faces the support plate 21, and the other second surface 10b of the pouch cell 10 faces away from the support plate 21.

[0145] As an example, at least a portion of the second surface 10b is formed in the second package portion. Alternatively, a portion of the second surface 10b is formed in the second package portion, and another portion of the second surface 10b is formed in the second sidewall 11132.

[0146] There can be one or more connecting beams 30. As an example, there can be multiple connecting beams 30, which are arranged along the first direction X, and soft-pack battery cells 10 are arranged between adjacent connecting beams 30.

[0147] The pouch cell 10 can directly abut against the connecting beam 30, or it can indirectly abut against the connecting beam 30 through other structures. For example, the pouch cell 10 abuts against the connecting beam 30 through other structures (such as a heat-conducting plate or heat-conducting adhesive).

[0148] It can be that only one pouch cell 10 abuts against the connecting beam 30 along the first direction X, or it can be that two pouch cell 10 abut against the connecting beam 30 along the first direction X. For example, the battery device 2 includes a plurality of battery cell assemblies, and at least one pouch cell 10 of each battery cell assembly abuts against the connecting beam 30 along the first direction X.

[0149] In some examples, the frame 22 is fixedly connected to the connecting beam 30. Optionally, both ends of the connecting beam 30 are welded to the frame 22 along the third direction Y.

[0150] In some examples, the connecting beam 30 is fixedly connected to the support plate 21. Alternatively, one end of the connecting beam 30 along the second direction Z is welded to the support plate 21.

[0151] As an example, electrode assembly 12 can be a wound structure or a stacked structure.

[0152] Areal density is a term known in the art. The areal density of the negative electrode film refers to the mass of the negative electrode film per unit area, which is equal to the mass of the negative electrode film divided by its area. For example, the areal density of the negative electrode film can be obtained by the following method: Disassemble the pouch cell, remove the negative electrode sheet; if both sides of the negative electrode current collector are provided with a negative electrode film, wipe off the negative electrode film on one side; punch out a small circular piece with an area of ​​S1 from the negative electrode sheet; weigh the small circular piece and record its mass as M1; then wipe off the negative electrode film from the weighed small circular piece, weigh the negative electrode current collector, and record its mass as M2. The areal density of the negative electrode film = (M1 - M2) / S1.

[0153] As an example, the areal density of the negative electrode film 1222 is 8.4 mg / cm³. 2 8.5 mg / cm 2 8.7 mg / cm 2 8.9 mg / cm 2 9.0 mg / cm 2 9.2 mg / cm 2 9.4 mg / cm 2 9.5 mg / cm 2 9.7 mg / cm 2 9.9 mg / cm 2 10.0 mg / cm 2 10.2 mg / cm 2 10.4 mg / cm 2 10.5 mg / cm 2 10.7 mg / cm 2 10.9 mg / cm 2 11.0 mg / cm 211.2 mg / cm 2 11.4 mg / cm 2 11.5 mg / cm 2 11.7 mg / cm 2 Or the value between any two of the above values.

[0154] As an example, the thickness T1 of the negative electrode film 1222 is 50μm, 52μm, 54μm, 55μm, 56μm, 58μm, 60μm, 62μm, 64μm, 65μm, 66μm, 68μm, 70μm, 72μm, 74μm, 75μm, 76μm, 78μm, 80μm, 82μm, 84μm, 85μm, 86μm, 88μm, 90μm, or any value between two of the above.

[0155] The negative terminal 13 is connected to the portion of the negative current collector 1221 that is not covered by the negative electrode film layer 1222. Exemplarily, the negative current collector 1221 is welded to the negative terminal 13.

[0156] The negative terminal 13 can pass between the two first encapsulation edges 11111 of the first encapsulation portion to extend from the inside of the packaging bag 11 to the outside of the packaging bag 11.

[0157] As an example, the first insulating member 14 may wrap around the negative terminal 13 to separate the negative terminal 13 from the first encapsulation edge 11111, reducing the risk of short circuit. The first insulating member 14 and the two first encapsulation edges 11111 are sealed together by heat fusion to form the first connection portion 15.

[0158] As an example, the dimension W1 of the first connecting part 15 along the third direction Y can be 2mm, 2.2mm, 2.5mm, 2.8mm, 3mm, 3.2mm, 3.5mm, 3.8mm, 4mm, 4.2mm, 4.5mm, 4.8mm, 5mm, 5.2mm, 5.5mm, 5.8mm, 6mm, or any value between any two of the above values.

[0159] As an example, the graphite in the negative electrode active material includes at least one of natural graphite and artificial graphite.

[0160] The volumetric distribution particle sizes Dv10 and Dv50 are well-known in the art, representing the particle size corresponding to a cumulative volume distribution percentage of 10% and 50%, respectively, and can be determined using instruments and methods known in the art. For example, they can be determined using a laser particle size analyzer, referring to GB / T 19077-2016. The testing instrument can be the Mastersizer 3000 laser particle size analyzer from Malvern Instruments Ltd., UK.

[0161] As an example, the volume distribution particle size Dv50 of the negative electrode active material is 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm or any two of the above values.

[0162] As an example, the volume distribution particle size Dv10 of the negative electrode active material is 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm or any value between two of the above.

[0163] In this embodiment, the pouch battery cell 10 has advantages such as light weight, flexible design, and high energy density. Using the pouch battery cell 10 helps improve the energy density of the battery device 2. The rated capacity of each pouch battery cell 10 is greater than or equal to 50 Ah, which helps improve the energy density of the battery device 2; the rated capacity of each pouch battery cell 10 is less than or equal to 300 Ah, which helps reduce the current during charging and discharging, thus reducing heat generation. The connecting beam 30 is fixedly connected to at least one of the support plate 21 and the frame 22, which helps improve the overall strength and rigidity of the battery device 2 and enhance its reliability. The connecting beam 30 and the pouch battery cell 10 are arranged along the first direction X, and the area of ​​the first surface 10a is relatively large. Therefore, the connecting beam 30 can constrain the expansion of the pouch battery cell 10, reduce its deformation, and improve its cycle performance. Using the connecting beam 30 to constrain the soft-pack battery cell 10 helps reduce the number of internal components of the housing 20, realizes the module-free design of the battery device 2, improves space utilization, and further enhances the energy density of the battery device 2.

[0164] In this embodiment, the areal density of the negative electrode film 1222 is set to 8.4 mg / cm³. 2 -11.7mg / cm 2 Setting the thickness of the negative electrode film layer 1222 to 50μm-90μm can give the negative electrode film layer 1222 a larger areal density and thickness, which is beneficial to improving the energy density of the soft-pack battery cell 10 and the energy density of the battery device 2.

[0165] In this embodiment, the volume distribution particle size Dv50 of the negative electrode active material is set to be less than or equal to 17 μm, and the volume distribution particle size Dv10 is set to be less than or equal to 9 μm. This is beneficial for shortening the ion insertion path, reducing the internal resistance of the pouch cell 10, reducing heat generation, lowering the temperature rise of the pouch cell 10, and reducing the heat conducted to the first connection portion 15. In this embodiment, the volume distribution particle size Dv50 of the negative electrode active material is set to be greater than or equal to 9 μm, and the volume distribution particle size Dv10 is set to be greater than or equal to 3 μm. This can reduce the content of negative electrode active material with a particle size less than 9 μm, especially reducing the content of negative electrode active material with a particle size less than 3 μm. This is beneficial for reducing the active sites of the negative electrode active material, reducing the specific surface area of ​​the negative electrode active material, reducing the decomposition and gas generation of the electrolyte, reducing the internal pressure of the pouch cell 10 during cycling, and reducing the force on the first connection portion 15. In this embodiment, the volume distribution particle size Dv50 of the negative electrode active material is set to 9μm-17μm, and the volume distribution particle size Dv10 is set to 3μm-9μm. This is beneficial for balancing the internal heat and gas generation of the pouch cell 10, balancing the force and heat effects on the first connection portion 15, improving the cycle performance of the pouch cell 10, and increasing its cycle life. In this embodiment, the dimension of the first connection portion 15 along the third direction Y is set to be greater than or equal to 2mm, which can improve the sealing strength. Therefore, when Dv50 is 9μm-17μm and Dv10 is 3μm-9μm, the problem of sealing failure easily occurring near the first connection portion 15 in the pouch cell 10 is reduced, thus improving the reliability of the battery device 2.

[0166] In this embodiment, the size of the first connecting part 15 along the third direction Y is set to be less than or equal to 6mm. This can reduce the space occupied by the first connecting part 15 in the third direction Y, improve space utilization, increase the energy density of the battery device 2, shorten the conductive path of the electrode terminals, reduce the internal resistance of the soft-pack battery cell, and improve the cycle life of the soft-pack battery cell and the battery device.

[0167] In this embodiment, the volume distribution particle size Dv50 of the negative electrode active material is set to 9μm-17μm, the volume distribution particle size Dv10 of the negative electrode active material is set to 3μm-9μm, and the size of the first connecting part 15 along the third direction Y is set to 2mm-6mm, which is beneficial to balance the reliability, cycle life and energy density of the battery device 2 to a certain extent.

[0168] In some embodiments, the volume distribution particle size Dv10 of the negative electrode active material is 5μm-7μm, and the volume distribution particle size Dv50 of the negative electrode active material is 11μm-15μm, which is beneficial to improving the reliability and cycle life of the soft-pack battery cell 10 and the battery device 2.

[0169] In some embodiments, the rated capacity of each pouch cell 10 is greater than or equal to 100 Ah and less than or equal to 200 Ah.

[0170] In some embodiments, the pouch cell 10 further includes an electrolyte contained within a packaging bag 11. The electrolyte additive includes vinylene carbonate, and the mass percentage of vinylene carbonate in the electrolyte is 0.5%-5%.

[0171] As an example, the mass percentage of vinylene carbonate in the electrolyte is 0.5%, 0.6%, 0.8%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, or any two of the above values.

[0172] Adding vinylene carbonate to the electrolyte helps improve the density and uniformity of the solid electrolyte interphase (SEI) film formed on the surface of the negative electrode 122, reduces electrolyte decomposition and side reactions, lowers the risk of sealing failure of the pouch cell 10, and improves the cycle life and reliability of the pouch cell 10.

[0173] In some embodiments, the pouch cell 10 further includes an electrolyte contained in a packaging bag 11, the electrolyte comprising a chain ester solvent, the chain ester solvent comprising 40% to 60% by mass in the electrolyte.

[0174] As an example, the mass percentage of the chain ester solvent in the electrolyte is 40%, 42%, 44%, 45%, 46%, 48%, 50%, 52%, 54%, 55%, 56%, 58%, 60%, or any two of the above values.

[0175] The types and contents of organic components in the electrolyte are well-known in the art and can be detected using well-known equipment and methods. For example, the organic components in the electrolyte can be qualitatively and quantitatively analyzed by gas chromatography using GB / T9722-2006 "General Rules for Gas Chromatography of Chemical Reagents". In the embodiments of this application, freshly prepared electrolyte can be used as a sample, or a fully discharged (discharged to the lower limit cutoff voltage so that the battery's state of charge is approximately 0% SOC) pouch cell can be disassembled, and the free electrolyte obtained from the pouch cell can be used as a sample for detection using ion chromatography.

[0176] In this embodiment, the mass ratio of chain ester solvent in the electrolyte is set to be greater than or equal to 40%, which makes the electrolyte conductivity relatively high, which is beneficial to improve the liquid phase transport capability of active ions, improve the fast charging and discharging capability of the pouch cell 10, and thus improve the rate performance of the pouch cell 10. The electrolyte system has relatively low viscosity, which makes it easier to flow, improves the uniformity of electrolyte distribution, and improves the cycle life of the pouch cell 10.

[0177] In this embodiment, the mass ratio of chain ester solvent in the electrolyte is set to less than or equal to 60% to reduce the decomposition and gas generation of chain ester solvent during the cycling process of the pouch cell 10, reduce the internal pressure of the pouch cell 10, reduce the probability of encapsulation failure near the first connection part 15, and further improve the reliability of the battery device 2.

[0178] In some embodiments, the electrolyte includes ethyl acetate.

[0179] In some embodiments, the pouch cell 10 further includes an electrolyte contained in a packaging bag 11, the electrolyte including dimethyl carbonate, the mass percentage of dimethyl carbonate in the electrolyte being 10% to 40%.

[0180] As an example, the mass percentage of dimethyl carbonate in the electrolyte is 10%, 12%, 14%, 15%, 16%, 18%, 20%, 22%, 24%, 25%, 26%, 28%, 30%, 32%, 34%, 35%, 36%, 38%, 40%, or any two of the above values.

[0181] In this embodiment, the mass percentage of dimethyl carbonate in the electrolyte is set to be greater than or equal to 10%, which is beneficial for building a low-viscosity electrolyte system, improving the ionic conductivity of the electrolyte, reducing the internal resistance of the pouch cell 10, reducing the heat generation of the pouch cell 10, and improving the kinetic performance of the pouch cell 10. In this embodiment, the mass percentage of dimethyl carbonate in the electrolyte is set to be less than or equal to 40%, which can reduce the amount of dimethyl carbonate vaporized or decomposed during the cycling process of the pouch cell 10, lower the internal gas pressure of the pouch cell 10, reduce the force on the first connection portion 15, and reduce the risk of sealing failure of the pouch cell 10 near the first connection portion 15.

[0182] In some embodiments, dimethyl carbonate accounts for 15% to 25% of the mass of the electrolyte. This embodiment can balance the kinetic performance and reliability of the battery device 2.

[0183] In some embodiments, the positive electrode film 1212 includes a conductive agent, which includes carbon nanotubes, and the carbon nanotubes include one or more of single-walled carbon nanotubes, few-walled carbon nanotubes, and multi-walled carbon nanotubes.

[0184] The term "carbon nanotubes" refers to nanotubes composed of carbon atoms arranged in sp... 2 Graphene sheets, formed by hybrid bonding, are rolled up to form nanomaterials with several to dozens of coaxial hollow cylindrical layers. Their diameters typically range from several to tens of nanometers, while their lengths can vary from micrometers to centimeters, exhibiting a high aspect ratio. Based on the number of layers, graphene sheets can be classified into: single-walled carbon nanotubes (SWCNTs), few-walled carbon nanotubes (FWCNTs), and multi-walled carbon nanotubes (MWCNTs). Carbon nanotubes possess excellent electrical conductivity and high elastic modulus.

[0185] Carbon nanotubes have a high aspect ratio, which facilitates the bonding of multiple lithium transition metal phosphate particles in the thickness direction of the positive electrode film 1212. This forms a long-range conductive path and increases the binding force between particles, reducing local polarization and even lithium plating problems in the pouch cell 10 during cycling, thus improving the cycle life of the pouch cell 10. Through the binding effect, carbon nanotubes can also reduce the rebound phenomenon of large particles in the positive electrode film 1212, further reducing the probability of contact and short circuit between the negative electrode film 1222 and the positive electrode film 1212, and reducing the amount of gas generated by the electrolyte due to high-temperature decomposition. This reduces the probability of encapsulation failure of the pouch cell 10 near the first connection 15, improves the cycle performance of the pouch cell 10, and gives the pouch cell 10 and battery device 2 good reliability.

[0186] In some embodiments, the carbon nanotubes in the positive electrode film 1212 account for 0.3%-0.7% of the total mass.

[0187] As an example, the mass percentage of carbon nanotubes in the positive electrode film 1212 is 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, or any value between two of the above.

[0188] In this embodiment, setting the mass percentage of carbon nanotubes in the positive electrode film layer 1212 to be greater than or equal to 0.3% can improve the cycle performance of the pouch cell 10. Setting the mass percentage of carbon nanotubes in the positive electrode film layer 1212 to be less than or equal to 0.7% helps reduce the risk of excessive carbon nanotube aggregation, ensuring uniform distribution of carbon nanotubes in the positive electrode film layer 1212 and improving the cycle performance of the pouch cell 10.

[0189] In some embodiments, the conductive agent further includes conductive carbon black. The conductive carbon black has a small size, adheres to the surface of lithium transition metal phosphate particles, and fills the gaps between the lithium transition metal phosphate particles, forming dense dot-like conductive contacts. Its use in conjunction with carbon nanotubes balances long-range and short-range conductivity, which is beneficial for further improving the conductive network in the positive electrode film 1212. Simultaneously, the conductive agent has a large specific surface area, which is beneficial for liquid absorption and retention, reducing electrolyte extrusion caused by the high expansion force increase of the electrode during long cycles, and improving the long cycle life of the pouch cell 10.

[0190] In some embodiments, the electrode assembly 12 includes a separator 123 disposed between the positive electrode 121 and the negative electrode 122. The separator 123 includes a base film 1231, an inorganic particle layer 1232, and an adhesive layer 1233. The inorganic particle layer 1232 is disposed on at least one side of the base film 1231, and the adhesive layer 1233 is disposed on at least one side of the inorganic particle layer 1232 away from the base film 1231. The adhesive layer 1233 is a continuous layer with a porous structure and includes a vinylidene fluoride polymer.

[0191] In some examples, the base film 1231 has an inorganic particle layer 1232 on only one side, and an adhesive layer 1233 is provided on the side of the inorganic particle layer 1232 away from the base film 1231.

[0192] In other examples, inorganic particle layers 1232 are provided on both sides of the base film 1231. The inorganic particle layers 1232 located on both sides of the base film 1231 are a first inorganic particle layer and a second inorganic particle layer, respectively. An adhesive layer 1233 is provided on the side of the first inorganic particle layer away from the base film 1231, and the surface of the second inorganic particle layer away from the base film 1231 may or may not have an adhesive layer 1233.

[0193] The adhesive layer 1233 has a certain porous structure in its continuous structure. Through the porous structure, the inorganic particle layer 1232 disposed between the base film 1231 and the adhesive layer 1233 can be observed. It is understood that when a porous continuous layer is used as the adhesive layer 1233, it may become blocky due to contact with the positive electrode 121 or the negative electrode 122 or under pressure during electrode manufacturing or cycling. The continuous layer referred to in this application does not require that the adhesive layer 1233 be continuous throughout the entire pouch cell 10; rather, it refers to a continuous layer with a uniform porous structure at the microscopic level, such as when observed under a microscope, rather than an island-like structure. To reflect the true morphology of the separator 123, during the sampling process, it is preferable to sample in areas where the adhesive layer 1233 of the separator 123 in the pouch cell 10 has minimal adhesion to the positive electrode 121 or negative electrode 122. For example, sampling can be performed on the separator 123 at a location extending beyond the positive electrode film 1212 and the negative electrode film 1222 in the third direction Y; or sampling can be performed on the separator 123 near the outer surface of the electrode assembly 12. The separator 123 sampled in this way better reflects the true state of the separator 123.

[0194] The inorganic particle layer 1232 can improve the thermal stability of the separator 123, reduce the shrinkage of the base film 1231 at high temperatures, and reduce the risk of thermal runaway of the pouch cell 10. The inorganic particle layer 1232 can improve the tensile strength and puncture resistance of the separator 123. The inorganic particle layer 1232 can reduce the risk of short circuit and improve the reliability of the pouch cell 10. The separator 123 provided in this embodiment uses a porous continuous layer as the adhesive layer 1233. The adhesive layer 1233 has a larger adhesive area, which makes the adhesion between the separator 123 and the electrode more firm and uniform. At the same time, with the help of the porous structure in the adhesive layer 1233, it can achieve both lithium-ion transport efficiency and kinetic performance of the pouch cell 10.

[0195] In this embodiment, a continuous layer with a porous structure is used as the adhesive layer 1233. This improves the adhesion between the separator 123 and the electrode while maintaining the air permeability and porosity of the separator 123, thereby improving the stability of the electrode, increasing the density and rigidity of the electrode assembly 12, reducing the risk of misalignment of the positive and negative electrode sheets 122, and improving the cycle performance of the soft-pack battery cell 10.

[0196] In some embodiments, polyvinylidene fluoride (PVDF) is dissolved in N-methylpyrrolidone (NMP), stirred until homogeneous, and then polyethylene glycol (PEG) is added as a pore-forming agent and thoroughly mixed to obtain an adhesive layer solution. The adhesive layer solution is applied to the aforementioned base film with inorganic particulate layers on both sides, pre-evaporated at 80°C and dried at 110°C, and then immersed in deionized water to dissolve the PEG, resulting in a separator with an adhesive layer having a porous structure on both sides.

[0197] In some embodiments, the electrode assembly 12 has a stacked structure. The adhesive layer 1233 can increase the interfacial shear force between the electrode and the separator 123, thereby reducing the relative slippage between the positive and negative electrode 122 under long-term cycling or mechanical impact, reducing the risk of breakage, and improving reliability.

[0198] In some embodiments, the vinylidene fluoride polymer includes one or more of vinylidene fluoride homopolymers and copolymers of vinylidene fluoride and hexafluoropropylene.

[0199] As an example, adhesive layer 1233 includes polyvinylidene fluoride (PVDF).

[0200] In some embodiments, the material of the base film 1231 may include, but is not limited to, one or more of glass fiber, nonwoven fabric, polyethylene (PE), and polypropylene (PP).

[0201] In some embodiments, the inorganic particle layer 1232 includes ceramic particles, which include one or more of Al2O3, AlO(OH), SiO2, TiO2, MgO, CaO, ZnO2, ZrO2, and SnO2.

[0202] Ceramic particles are flame-retardant and have high hardness, making them resistant to deformation under heat and thus exhibiting excellent dimensional stability. The inorganic particle layer 1232 disposed on both sides of the base film 1231 helps improve the rigidity of the pouch cell 10, reduces the probability of contact and short circuit between the negative electrode film layer 1222 and the positive electrode film layer 1212, and consequently reduces the amount of gas generated by electrolyte decomposition at high temperatures. This reduces the probability of encapsulation failure of the pouch cell 10 near the first connection portion 15, improving the reliability of the pouch cell 10.

[0203] In some embodiments, inorganic particle layers 1232 are provided on both sides of the base film 1231. An adhesive layer 1233 is provided on the surface of each inorganic particle layer 1232.

[0204] The adhesive layers 1233 located on both sides of the base film 1231 are respectively bonded to the positive electrode film layer 1212 and the negative electrode film layer 1222.

[0205] In some embodiments, the ratio of the thickness T2 of the negative current collector 1221 to the thickness T3 of the negative electrode sheet 122 is 3%-7%.

[0206] As an example, T3 = T1 × 2 + T2.

[0207] As an example, T2 / T3 can be 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, or any value between any two of the above.

[0208] In this embodiment, T2 / T3 is set to less than or equal to 7% to reduce the space and weight occupied by the negative electrode current collector 1221, increase the thickness ratio of the negative electrode film layer 1222 in the negative electrode sheet 122, which is beneficial to improving the energy density of the pouch cell 10. In this embodiment, T2 / T3 is set to greater than or equal to 3% to give the negative electrode current collector 1221 better current carrying capacity, reduce the internal resistance of the pouch cell 10, and reduce the internal heat generation of the pouch cell 10.

[0209] In some embodiments, the negative electrode current collector 1221 includes a negative electrode current collector portion 12212 and a negative electrode tab 12211. The negative electrode tab 12211 is located on the side of the negative electrode current collector portion 12212 near the negative terminal 13. At least a portion of the negative electrode film layer 1222 is disposed in the negative electrode current collector portion 12212, and at least a portion of the negative electrode tab 12211 is not provided with the negative electrode film layer 1222.

[0210] The negative current collector 12212 and the negative electrode tab 12211 are arranged along the third direction Y. Optionally, the negative electrode tab 12211 protrudes from the negative current collector 12212.

[0211] In some examples, the electrode assembly 12 is a stacked structure, and the negative current collector 1221 includes a negative tab 12211. In other examples, the electrode assembly 12 is a wound structure, and the negative current collector 1221 includes multiple negative tabs 12211. The multiple negative tabs 12211 are located on one side of the negative current collector 12212 along the third direction Y, and the multiple negative tabs 12211 are arranged along the winding direction of the electrode assembly 12, and the multiple negative tabs 12211 are stacked along the first direction X.

[0212] In some embodiments, the pouch cell 10 further includes a positive terminal 16. One end of the positive terminal 16 is located inside the packaging bag 11, and the other end is located outside the packaging bag 11.

[0213] The positive current collector 1211 includes a positive current collector section 12112 and a positive electrode tab 12111. The positive electrode tab 12111 is located on the side of the positive current collector section 12112 near the positive terminal 16. At least a portion of the positive electrode film layer 1212 is disposed in the positive current collector section 12112, and at least a portion of the positive electrode tab 12111 is not provided with the positive electrode film layer 1212. The positive electrode tab 12111 is connected to the positive terminal 16.

[0214] The positive current collector 12112 and the positive electrode tab 12111 are arranged along the third direction Y. Optionally, the positive electrode tab 12111 protrudes from the positive current collector 12112.

[0215] The positive terminal 16 and the negative terminal 13 can extend from the same side of the packaging bag 11 along the third party toward Y, or they can extend from both sides of the packaging bag 11 along the third party toward Y.

[0216] In some examples, the electrode assembly 12 is a stacked structure, and the positive current collector 1211 includes a positive tab 12111. In other examples, the electrode assembly 12 is a wound structure, and the positive current collector 1211 includes multiple positive tabs 12111. The multiple positive tabs 12111 are located on one side of the positive current collector 12112 along the third direction Y, and the multiple positive tabs 12111 are arranged along the winding direction of the electrode assembly 12, and the multiple positive tabs 12111 are stacked along the first direction X.

[0217] In some embodiments, in the second direction Z, the ratio of the width W2 of the negative end 13 to the width W3 of the packaging bag 11 is 0.2-0.5.

[0218] As an example, W2 / W3 can be 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, or any value between any two of the above.

[0219] In this embodiment, setting W2 / W3 to be greater than or equal to 0.2 can increase the current carrying capacity of the negative terminal 13 and reduce the heat generation of the negative terminal 13. Setting W2 / W3 to be less than or equal to 0.5 can reduce the packaging difficulty of the negative terminal 13, decrease the sealing interface between the first insulator 14 and the packaging bag 11, and between the first insulator 14 and the negative terminal 13, thus reducing the risk of seal failure. Setting W2 / W3 to 0.2-0.5 in this embodiment helps reduce the risk of seal failure of the pouch battery cell 10 and improves the reliability of the battery device 2.

[0220] In some embodiments, the width W2 of the negative terminal 13 is 25mm-65mm. As an example, W2 is 25mm, 30mm, 35mm, 40mm, 45mm, 50mm, 55mm, 60mm, 65mm or any value between the above two values.

[0221] In some embodiments, the dimension L0 of the pouch cell 10 in the third direction Y is 500mm-1250mm. As an example, L0 can be selected as 500mm, 510mm, 520mm, 530mm, 540mm, 550mm, 560mm, 570mm, 580mm, 590mm, 600mm, 610mm, 620mm, 630mm, 640mm, 650mm, 660mm, 670mm, 680mm, 690mm, 700mm, 710mm, 720mm, 750mm, 800mm, 850mm, 900mm, 950mm, 1000mm, 1050mm, 1100mm, 1150mm, 1200mm, 1250mm, or any value between any two of the above.

[0222] It should be noted that L0 does not take into account the dimensions of the positive terminal 16 and the negative terminal 13. That is, the dimension L0 of the soft-pack battery cell 10 in the third direction Y is equal to the dimension of the packaging bag 11 in the third direction Y.

[0223] Setting L0 to greater than or equal to 500 mm is beneficial to increasing the capacity of the pouch cell 10; setting L0 to less than or equal to 1250 mm is beneficial to shortening the electron transport path, reducing the internal resistance of the pouch cell 10, thereby reducing the heat generation of the pouch cell 10; under fast charging conditions, this embodiment can reduce the phenomenon of uneven temperature rise and uneven current density of the electrode in the length direction, and improve the cycle performance of the pouch cell 10.

[0224] In some embodiments, the dimension L0 of the pouch cell 10 in the third direction Y is 500mm-650mm. The shorter length of the pouch cell 10 is beneficial for reducing internal resistance and internal heat generation.

[0225] In other embodiments, the dimension L0 of the pouch cell 10 in the third direction Y is 900mm-1250mm.

[0226] The pouch battery cell 10 is relatively long. Using a large-sized pouch battery cell 10 is beneficial for achieving module-free integration, reducing the number of battery cell components, significantly improving space utilization, reducing the number of structural components, and increasing the energy density of the battery device 2.

[0227] In some embodiments, the dimension W0 of the pouch cell 10 in the second direction Z is 100mm-150mm.

[0228] As an example, W0 can be selected as 100mm, 110mm, 120mm, 130mm, 140mm, 150mm, or any value between two of the above. Optionally, W0 is equal to W3.

[0229] Setting W0 to greater than or equal to 100mm is beneficial to increasing the capacity of the pouch cell 10; setting W0 to less than or equal to 150mm is beneficial to reducing the height of the pouch cell 10, reducing the difficulty of electrolyte wetting, improving electrolyte wetting consistency, and enhancing the cycle performance of the pouch cell 10.

[0230] In some embodiments, the dimension H0 of the pouch cell 10 in the first direction X is 14mm-22mm.

[0231] As an example, H0 can be selected as 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, 21mm, 22mm or any value between any two of the above.

[0232] Setting H0 to greater than or equal to 14mm is beneficial to increasing the capacity of the soft-pack battery cell 10; setting H0 to less than or equal to 22mm can reduce the heat generation of the electrode assembly 12 and reduce the difficulty of heat dissipation of the electrode assembly 12.

[0233] In some embodiments, L0 is 500mm-1250mm, W0 is 100mm-150mm, and H0 is 14mm-22mm. Having the dimensions of the pouch cell 10 within these ranges is beneficial for optimizing the arrangement of the pouch cell 10, improving space utilization, and increasing the energy density of the battery device 2.

[0234] In some embodiments, the electrode assembly 12 has a stacked structure. Using the electrode assembly 12 with a stacked structure can improve the energy density of the pouch cell 10.

[0235] As an example, the electrode assembly 12 includes a plurality of positive electrode plates 121 and a plurality of negative electrode plates 122, which are alternately stacked along a first direction X. Each positive electrode plate 121 is provided with at least one positive electrode tab 12111, and each negative electrode plate 122 is provided with at least one negative electrode tab 12211.

[0236] Figure 13 for Figure 8 Enlarged illustration within the box; Figure 14 A cross-sectional schematic diagram of the negative terminal of a pouch cell in a battery device provided in some embodiments of this application; Figure 15 A schematic diagram of a partial structure of a pouch battery cell for a battery device provided in some embodiments of this application; Figure 16 This is another partial cross-sectional schematic diagram of a pouch cell for a battery device provided in some embodiments of this application.

[0237] Reference Figures 13 to 16 In some embodiments, multiple negative tabs 12211 are welded to the negative terminal 13 to form a second connection portion 17, which is spaced apart from the first connection portion 15.

[0238] During the charging and discharging process of the battery device 2, the second connection portion 17 generates heat under the action of current. In this embodiment, the second connection portion 17 and the first connection portion 15 are spaced apart to reduce the heat conducted from the second connection portion 17 to the first connection portion 15, thereby reducing the temperature rise of the first connection portion 15 during the charging and discharging process of the battery device 2, slowing down the fatigue aging of the first connection portion 15, reducing the risk of sealing failure of the pouch battery cell 10, and improving the reliability of the battery device 2.

[0239] In some embodiments, a plurality of negative electrode tabs 12211 are stacked to form a negative electrode tab portion. The negative electrode terminal 13 and the negative electrode tab portion are stacked along a first direction X.

[0240] In some embodiments, along the third direction Y, the minimum distance D1 between the second connecting portion 17 and the first connecting portion 15 is 1.5mm-7mm.

[0241] As an example, along the third direction Y, the minimum distance between the second connecting part 17 and the first connecting part 15 can be 1.5mm, 1.8mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm or any two of the above values.

[0242] In this embodiment, setting D1 to be greater than or equal to 2mm reduces heat conduction from the second connection portion 17 to the first connection portion 15, thereby reducing the temperature rise of the first connection portion 15 during the charging and discharging process of the battery device 2, slowing down fatigue aging of the first connection portion 15, reducing the risk of sealing failure of the pouch battery cell 10, and improving the reliability of the battery device 2. Setting D1 to be less than or equal to 7mm in this embodiment saves space while maintaining the energy density of the pouch battery cell 10.

[0243] In some embodiments, the area of ​​the second connecting portion 17 is 20 mm. 2 Up to 60 mm 2 .

[0244] As an example, the area of ​​the second connecting part 17 can be 20 mm. 2 22mm 2 25mm 2 28mm 2 30mm 2 32mm 2 35mm 2 38mm 2 40mm 2 42mm 2 45mm 2 48mm 2 50mm 2 52mm 2 55mm 2 58mm 2 60mm 2 Or the value between any two of the above values.

[0245] As an example, the negative terminal 13 and the negative terminal lug can be connected by laser welding. For instance, a laser can irradiate the surface of the negative terminal lug away from the negative terminal 13, melting a portion of the negative terminal lug and a portion of the negative terminal 13 to form a molten pool. After the molten pool solidifies, at least one first weld portion 171 is formed. The second connection portion 17 includes all the first weld portions 171. Along the stacking direction of the negative terminal lug and the negative terminal 13, viewed from the side of the negative terminal lug away from the negative terminal 13, the area enclosed by the outer contour of the first weld portions 171 can be used as the area of ​​the first weld portions 171. The area of ​​the second connection portion 17 is equal to the sum of the areas of all the first weld portions 171.

[0246] In this embodiment, the area of ​​the second connecting portion 17 is set to be greater than or equal to 20 mm. 2 This can reduce the resistance of the second connection portion 17, improve its overcurrent capacity, reduce heat generation, lower its temperature rise, reduce the risk of electrolyte decomposition, reduce heat conducted to the first connection portion 15, slow down fatigue aging of the first connection portion 15, and reduce the risk of sealing failure of the pouch cell 10 near the first connection portion 15. In this embodiment, the area of ​​the second connection portion 17 is set to be greater than or equal to 20 mm². 2 This also reduces the resistance of the second connection portion 17, thereby improving the cycle life of the pouch battery cell 10. In this embodiment, the area of ​​the second connection portion 17 is set to be less than or equal to 60 mm². 2 This can reduce the space occupied by the second connection part 17, thereby reducing the size requirements of the negative electrode tab 12211 and the negative terminal 13, and reducing the impact of increasing the area of ​​the second connection part 17 on the energy density of the soft-pack battery cell 10.

[0247] In some embodiments, the area of ​​the second connecting portion 17 is 30 mm. 2 Up to 50mm 2 This embodiment can further balance the energy density and reliability of battery device 2.

[0248] In some embodiments, the negative terminal 13 has a sheet-like structure. As an example, the thickness direction of the negative terminal 13 is parallel to the first direction X.

[0249] In some embodiments, the end of the first insulating member 14 near the negative current collector 12212 extends inward beyond the first connecting portion 15 along the third direction Y. This embodiment can reduce the risk of heat pressing to the inside of the first insulating member 14 due to errors when connecting the first insulating member 14 and the packaging bag 11.

[0250] In some embodiments, the first insulating member 14 and the second connecting portion 17 are spaced apart in the third direction Y. This embodiment separates the first insulating member 14 and the second connecting portion 17, thereby reducing the heat conducted to the first insulating member 14, slowing down the fatigue aging of the first connecting portion 15, reducing the risk of sealing failure of the pouch battery cell 10, and improving the reliability of the battery device 2.

[0251] In some embodiments, in the third-party direction Y, the distance D2 between the first insulating member 14 and the second connecting portion 17 is greater than or equal to 0.5 mm.

[0252] In this embodiment, the distance between the first insulating member 14 and the second connecting part 17 is set to be greater than or equal to 0.5 mm, which can increase the heat transfer path between the second connecting part 17 and the first insulating member 14 and reduce the heat conducted to the first connecting part 15.

[0253] In some embodiments, the second connection portion 17 includes at least one first weld portion 171. Exemplarily, the first weld portion 171 may be dot-shaped or line-shaped.

[0254] In some embodiments, the first weld portion 171 is formed by laser welding. A recess may be formed on the side of the first weld portion 171 away from the negative terminal 13.

[0255] In some embodiments, the second connection portion 17 includes a plurality of first welding portions 171. By providing a plurality of first welding portions 171, heat accumulation during welding can be reduced, heat conducted to the separator 123 of the electrode assembly 12 can be reduced, the risk of shrinkage and deformation of the separator 123 can be reduced, and the reliability of the pouch cell 10 can be improved.

[0256] In some embodiments, the first weld portion 171 is dotted.

[0257] In some embodiments, the second connection portion 17 includes a linear first welding portion 171 (not shown). The first welding portion 171 may be straight, S-shaped, V-shaped, W-shaped, or other shapes.

[0258] The linear first welded part 171 can be one or more.

[0259] The use of a linear first welding section 171 facilitates continuous welding and improves welding efficiency.

[0260] In some embodiments, a plurality of negative electrode tabs 12211 are welded together to form a second weld portion 124. A portion of the second weld portion 124 is welded to the negative terminal 13 to form a second connection portion 17.

[0261] As an example, during welding, a portion of the second weld portion 124 and a portion of the negative terminal 13 melt and form a molten pool, which solidifies to form the second connection portion 17. Optionally, during welding, a laser irradiates the second weld portion 124.

[0262] The second connecting part 17 is directly connected to the second welding part 124, which helps to reduce the risk of the negative electrode tab 12211 and the second connecting part 17 disconnecting, reduce the resistance between the negative electrode tab 12211 and the negative terminal 13, and reduce heat generation.

[0263] In some embodiments, a plurality of negative electrode tabs 12211 may be ultrasonically welded to form a second welded portion 124.

[0264] As an example, multiple negative electrode tabs 12211 can be pre-welded to form a second welded portion 124, and then the second welded portion 124 can be welded to the negative terminal 13 to form a first welded portion 171.

[0265] In some embodiments, a plurality of negative tabs 12211 are stacked with a negative terminal along a first direction X. The pouch cell 10 also includes a second insulating member 18, which is disposed on the side of the plurality of negative tabs 12211 away from the negative terminal 13 and covers the second connection portion 17 in the first direction X.

[0266] The second insulating member 18 may completely cover the second connecting portion 17, or it may only cover a portion of the second connecting portion 17.

[0267] The second insulating member 18 can cover impurities remaining on the surface of the second connection portion 17, reducing the risk of impurities falling into the electrode assembly 12 and improving reliability. The second insulating member 18 can also separate at least a portion of the second connection portion 17 from the packaging bag 11, reducing the risk of the second connection portion 17 scratching the packaging bag 11.

[0268] In some embodiments, the second insulating element 18 comprises insulating tape. In other embodiments, the second insulating element 18 comprises insulating colloid; the insulating colloid cures to form the second insulating element 18.

[0269] In some embodiments, the second insulation element 18 includes a heat-insulating adhesive. Optionally, the material of the second insulation element 18 is polyethylene terephthalate or polyimide.

[0270] In some embodiments, the thickness of the second insulating element 18 is 20 μm-70 μm. As an example, the thickness of the second insulating element 18 is 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, or any value between two of the above.

[0271] In some embodiments, the second insulating member 18 completely covers the second connecting portion 17.

[0272] In some embodiments, in the first direction X, the second connecting portion 17 is spaced apart from the surface of the negative terminal 13 away from the negative electrode tab 12211.

[0273] This embodiment can reduce the risk of the negative terminal 13 being melted through when welding multiple negative tabs 12211 and negative terminals 13.

[0274] In some embodiments, the second insulating member 18 is spaced apart from the first insulating member 14. This embodiment separates the second insulating member 18 from the first insulating member 14, thereby reducing the heat conducted to the first insulating member 14, slowing down the fatigue aging of the first connection portion 15, reducing the risk of sealing failure of the pouch battery cell 10, and improving the reliability of the battery device 2.

[0275] In some embodiments, the thermal conductivity of the negative terminal 13 is greater than or equal to 200 W / (m·K). As an example, the thermal conductivity of the negative terminal 13 is 200 W / (m·K), 230 W / (m·K), 250 W / (m·K), 280 W / (m·K), 300 W / (m·K), 330 W / (m·K), 350 W / (m·K), 380 W / (m·K), 400 W / (m·K), 430 W / (m·K), 450 W / (m·K), 500 W / (m·K), 600 W / (m·K), or a value between any two of the above.

[0276] The negative terminal 13 has good thermal conductivity, which helps to quickly conduct heat to the outside of the packaging bag 11, reduce the internal temperature of the soft-pack battery cell 10, reduce the risk of electrolyte decomposition and gas generation, improve the cycle life and cycle performance of the soft-pack battery cell 10, and reduce the risk of sealing failure of the soft-pack battery cell 10.

[0277] In some embodiments, the negative terminal 13 includes a terminal body 131 and a nickel layer 132 disposed on the surface of the terminal body 131, wherein the base material of the terminal body 131 is copper. Copper has good electrical and thermal conductivity, while nickel has good corrosion resistance. This embodiment can improve the conductivity and stability of the negative terminal 13.

[0278] In some embodiments, the thickness of the negative terminal 13 is 0.2 mm to 0.5 mm.

[0279] In some embodiments, in the third direction Y, the positive electrode tab 12111 and the negative electrode tab 12211 are located at both ends of the electrode assembly 12, respectively. The positive terminal 16 and the negative terminal 13 extend from the packaging bag 11 on both sides along the third direction Y, respectively.

[0280] For example, the positive terminal 16 passes between the two first package edges 11111 of one first package portion, and the negative terminal 13 passes between the two first package edges 11111 of another first package portion.

[0281] In this embodiment, the positive terminal 16 and the negative terminal 13 are respectively disposed at both ends of the electrode assembly 12 along the third direction Y. This can reduce the risk of the positive terminal 16 and the negative terminal 13 being turned on, and it is also beneficial to increase the size of the positive terminal 16 and the negative terminal 13 along the second direction Z, thereby improving the current carrying capacity and reducing heat generation.

[0282] In some embodiments, the pouch cell 10 further includes a third insulating member 191, which surrounds the positive terminal 16 and is disposed between the positive terminal 16 and the packaging bag 11. The third insulating member 191 is sealed to the packaging bag 11 and forms a third connection portion 192, which is located on one side of the electrode assembly 12 along a third direction Y. Exemplarily, the first connection portion 15 and the third connection portion 192 are located on both sides of the electrode assembly 12.

[0283] As an example, the third insulating member 191 may wrap around the positive terminal 16 to separate the positive terminal 16 from the first encapsulation edge 11111, reducing the risk of short circuit. The third insulating member 191 and the two first encapsulation edges 11111 are sealed together by heat fusion to form the third connection portion 192.

[0284] In some embodiments, the dimension of the third connecting portion 192 along the third direction Y is 2mm-6mm. As an example, the dimension of the third connecting portion 192 along the third direction Y can be 2mm, 2.2mm, 2.5mm, 2.8mm, 3mm, 3.2mm, 3.5mm, 3.8mm, 4mm, 4.2mm, 4.5mm, 4.8mm, 5mm, 5.2mm, 5.5mm, 5.8mm, 6mm, or any value between any two of the above values.

[0285] In some embodiments, in the second direction Z, the ratio of the width of the positive terminal 16 to the width W3 of the packaging bag 11 is 0.2-0.5. As an example, the ratio of the width of the positive terminal 16 to the width of the packaging bag 11 may be 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, or any value between any two of the above.

[0286] In some embodiments, the positive terminal 16 is a sheet-like structure. As an example, the thickness direction of the positive terminal 16 is parallel to the first direction X.

[0287] In some embodiments, the width of the positive terminal 16 may be 25mm-65mm.

[0288] In some embodiments, the thickness of the positive terminal 16 is 0.2 mm to 0.5 mm.

[0289] In some embodiments, the base material of the positive terminal 16 is aluminum. The base material of the positive terminal 16 refers to the material with the largest mass proportion in the positive terminal 16.

[0290] Aluminum has high electrical and thermal conductivity. Using aluminum as the base material for the positive terminal 16 helps reduce heat generation in the second connection part 17 and lowers the risk of failure of the first connection part 15.

[0291] In some embodiments, the thickness of the positive terminal 16 is equal to the thickness of the negative terminal 13.

[0292] In some embodiments, a plurality of positive tabs 12111 are welded to the positive terminal 16 to form a fourth connection portion 193, which is spaced apart from the third connection portion 192. During the charging and discharging process of the battery device 2, the fourth connection portion 193 generates heat under the action of current. In this embodiment, the fourth connection portion 193 and the third connection portion 192 are spaced apart to reduce the heat conducted from the fourth connection portion 193 to the third connection portion 192, reduce the temperature rise of the third connection portion 192 during the charging and discharging process of the battery device 2, slow down the fatigue aging of the third connection portion 192, reduce the risk of sealing failure of the pouch battery cell 10, and improve the reliability of the battery device 2.

[0293] In some embodiments, a plurality of positive electrode tabs 12111 are stacked to form a positive electrode tab portion. The positive terminal 16 and the positive electrode tab portion are stacked along a first direction X.

[0294] In some embodiments, the minimum distance between the fourth connecting portion 193 and the third connecting portion 192 along the third direction Y can be 1.5mm-7mm. For example, the minimum distance can be 1.5mm, 1.8mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, or any value between any two of the above values.

[0295] In some embodiments, the area of ​​the fourth connecting portion 193 is 20 mm. 2 Up to 60 mm 2 .

[0296] As an example, the area of ​​the fourth connecting part 193 can be 20 mm. 2 22mm 2 25mm 2 28mm 2 30mm 2 32mm 2 35mm 2 38mm2 40mm 2 42mm 2 45mm 2 48mm 2 50mm 2 52mm 2 55mm 2 58mm 2 60mm 2 Or the value between any two of the above values.

[0297] As an example, the positive terminal 16 and the positive terminal tab can be connected by laser welding. For instance, a laser can irradiate the surface of the positive terminal tab away from the positive terminal 16, melting a portion of the positive terminal tab and a portion of the positive terminal 16 to form a molten pool. After the molten pool solidifies, at least one third weld portion 1931 is formed. The fourth connection portion 193 includes all the third weld portions 1931. Along the stacking direction of the positive terminal tab and the positive terminal 16, viewed from the side of the positive terminal tab away from the positive terminal 16, the area enclosed by the outer contour of the third weld portions 1931 can be used as the area of ​​the third weld portions 1931. The area of ​​the fourth connection portion 193 is equal to the sum of the areas of all the third weld portions 1931.

[0298] In this embodiment, the area of ​​the fourth connecting part 193 is set to be greater than or equal to 20 mm². 2 This can reduce the resistance of the fourth connection portion 193, improve its overcurrent capacity, reduce heat generation, lower its temperature rise, reduce the risk of electrolyte decomposition, reduce heat conducted to the third connection portion 192, slow down fatigue aging of the third connection portion 192, reduce the risk of sealing failure of the pouch cell 10 near the third connection portion 192, and improve the cycle life of the pouch cell. In this embodiment, the area of ​​the fourth connection portion 193 is set to be less than or equal to 60 mm². 2 This can reduce the space occupied by the fourth connection part 193, thereby reducing the size requirements of the positive tab 12111 and the positive terminal 16, and reducing the impact of increasing the area of ​​the fourth connection part 193 on the energy density of the pouch cell 10.

[0299] In some embodiments, the area of ​​the fourth connecting portion 193 is 30 mm. 2 Up to 50mm 2 This embodiment can further balance the energy density and reliability of battery device 2.

[0300] In some embodiments, the end of the third insulating member 191 near the positive current collector 12112 extends inward beyond the third connecting portion 192 along the third direction Y. This embodiment can reduce the risk of heat pressing onto the inner side of the third insulating member 191 due to errors when connecting the third insulating member 191 and the packaging bag 11.

[0301] In some embodiments, the third insulating member 191 and the fourth connecting portion 193 are spaced apart in the third direction Y. This embodiment separates the third insulating member 191 and the fourth connecting portion 193, thereby reducing the heat conducted to the third insulating member 191, slowing down the fatigue aging of the third connecting portion 192, reducing the risk of sealing failure of the pouch cell 10, and improving the reliability of the battery device 2.

[0302] In some embodiments, in the third direction Y, the distance between the third insulating member 191 and the fourth connecting portion 193 is greater than or equal to 0.5 mm.

[0303] In this embodiment, the distance between the third insulating member 191 and the fourth connecting part 193 is set to be greater than or equal to 0.5 mm, which can increase the heat transfer path between the fourth connecting part 193 and the third insulating member 191 and reduce the heat conducted to the third connecting part 192.

[0304] In some embodiments, the fourth connection portion 193 includes at least one third weld portion 1931. Exemplarily, the third weld portion 1931 may be dot-shaped or line-shaped.

[0305] In some embodiments, the third weld portion 1931 is formed by laser welding. A recess may be formed on the side of the third weld portion 1931 away from the positive terminal 16.

[0306] In some embodiments, the fourth connection portion 193 includes a plurality of third welding portions 1931. By providing a plurality of third welding portions 1931, heat accumulation during welding can be reduced, heat conducted to the separator 123 of the electrode assembly 12 can be reduced, the risk of shrinkage and deformation of the separator 123 can be reduced, and the reliability of the pouch cell 10 can be improved.

[0307] In some embodiments, the third weld portion 1931 is dotted.

[0308] In some embodiments, the fourth connecting portion 193 includes a linear third welding portion 1931 (not shown). The third welding portion 1931 may be straight, S-shaped, V-shaped, W-shaped, or other shapes.

[0309] The linear third welded part 1931 can be one or more.

[0310] The use of a linear third welding section 1931 facilitates continuous welding and improves welding efficiency.

[0311] In some embodiments, a plurality of positive tabs 12111 are welded together to form a fourth weld portion 125. A portion of the fourth weld portion 125 is welded to the positive terminal 16 to form a fourth connection portion 193.

[0312] As an example, during welding, a portion of the fourth weld portion 125 and a portion of the positive terminal 16 melt to form a molten pool, which solidifies to form the fourth connection portion 193. Optionally, during welding, a laser irradiates the fourth weld portion 125.

[0313] The fourth connecting part 193 is directly connected to the fourth welding part 125, which helps to reduce the risk of disconnection between the positive electrode tab 12111 and the fourth connecting part 193, reduce the resistance between the positive electrode tab 12111 and the positive terminal 16, and reduce heat generation.

[0314] In some embodiments, a plurality of positive tabs 12111 can be ultrasonically welded to form a fourth welded portion 125.

[0315] As an example, multiple positive electrode tabs 12111 can be pre-welded to form a fourth welded part 125, and then the fourth welded part 125 can be welded to the positive electrode 16 to form a third welded part 1931.

[0316] In some embodiments, a plurality of positive tabs 12111 are stacked with a positive terminal along a first direction X. The pouch cell 10 also includes a fourth insulating member 194, which is disposed on the side of the plurality of positive tabs 12111 away from the positive terminal 16 and covers the fourth connection portion 193 in the first direction X.

[0317] The fourth insulating member 194 may completely cover the fourth connecting portion 193, or it may only cover a portion of the fourth connecting portion 193.

[0318] The fourth insulating element 194 can cover impurities remaining on the surface of the fourth connection portion 193, reducing the risk of impurities falling into the electrode assembly 12 and improving reliability. The fourth insulating element 194 can also separate at least a portion of the fourth connection portion 193 from the packaging bag 11, reducing the risk of the fourth connection portion 193 scratching the packaging bag 11.

[0319] In some embodiments, the fourth insulating element 194 comprises insulating tape. In other embodiments, the fourth insulating element 194 comprises insulating colloid; the insulating colloid cures to form the fourth insulating element 194.

[0320] In some embodiments, the fourth insulating element 194 includes a heat-insulating adhesive. Optionally, the material of the fourth insulating element 194 is polyethylene terephthalate or polyimide.

[0321] In some embodiments, the thickness of the fourth insulating element 194 is 20 μm-70 μm. As an example, the thickness of the fourth insulating element 194 is 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, or any value between two of the above.

[0322] In some embodiments, the fourth insulating member 194 completely covers the fourth connecting portion 193.

[0323] In some embodiments, in the first direction X, the fourth connection portion 193 is spaced apart from the surface of the positive terminal 16 away from the positive electrode tab 12111.

[0324] This embodiment can reduce the risk of the positive terminal 16 being melted through when welding multiple positive tabs 12111 and positive terminal 16.

[0325] In some embodiments, the fourth insulating member 194 is spaced apart from the third insulating member 191. This embodiment separates the fourth insulating member 194 from the third insulating member 191, thereby reducing the heat conducted to the third insulating member 191, slowing down the fatigue aging of the third connection portion 192, reducing the risk of sealing failure of the pouch cell 10, and improving the reliability of the battery device 2.

[0326] In some embodiments, the thermal conductivity of the positive terminal 16 is greater than or equal to 200 W / (m·K).

[0327] As an example, the thermal conductivity of the positive terminal 16 is 200 W / (m·K), 230 W / (m·K), 250 W / (m·K), 280 W / (m·K), 300 W / (m·K), 330 W / (m·K), 350 W / (m·K), 380 W / (m·K), 400 W / (m·K), 430 W / (m·K), 450 W / (m·K), 500 W / (m·K), 600 W / (m·K), or any value between any two of the above.

[0328] The positive terminal 16 has good thermal conductivity, which helps to quickly conduct heat to the outside of the packaging bag 11, reduce the internal temperature of the soft-pack battery cell 10, reduce the risk of electrolyte decomposition and gas generation, improve the cycle life and cycle performance of the soft-pack battery cell 10, and reduce the risk of sealing failure of the soft-pack battery cell 10.

[0329] In some embodiments, the packaging bag 11 includes a stacked encapsulation layer 11a, a metal layer 11b, and a protective layer 11c. The encapsulation layer 11a is located on the surface of the metal layer 11b facing the electrode assembly 12. The encapsulation layer 11a is fused to the first insulating member 14 and forms a first connection portion 15.

[0330] A portion of the encapsulation layer 11a and a portion of the first insulating member 14 are fused together, bonded to each other, and form a first connection portion 15.

[0331] As an example, metal layer 11b can be an aluminum layer or a steel layer.

[0332] As an example, each packaging film 111 includes an encapsulation layer 11a, a metal layer 11b, and a protective layer 11c. The encapsulation layers 11a of two packaging films 111 are fused together to form a welded section.

[0333] The first insulating element 14 is fused to the encapsulation layer 11a of the two packaging films 111. Specifically, the encapsulation layer 11a of the first encapsulation edge 11111 of one packaging film 111 is fused to the first insulating element 14, and the encapsulation layer 11a of the first encapsulation edge 11111 of the other packaging film 111 is fused to the first insulating element 14.

[0334] By adopting a multi-layered structure, the strength and weight of the packaging bag 11 can be balanced, thereby increasing the energy density of the pouch battery cell 10. The metal layer 11b can reduce the penetration of water and oxygen into the interior of the packaging bag 11, reduce the decomposition of the electrolyte and the oxidation of the electrode materials, thus improving the lifespan of the pouch battery cell 10. The encapsulation layer 11a is fused to the first insulating member 14, which helps to improve the connection strength and sealing performance.

[0335] In some embodiments, the encapsulation layer 11a is fused to the third insulating member 191 and forms a third connection portion 192.

[0336] A portion of the encapsulation layer 11a and a portion of the third insulating member 191 are fused together, bonded to each other, and form a third connection portion 192.

[0337] The third insulating element 191 is fused to the encapsulation layer 11a of the two packaging films 111. Specifically, the encapsulation layer 11a of the first encapsulation edge 11111 of one packaging film 111 is fused to the third insulating element 191, and the encapsulation layer 11a of the first encapsulation edge 11111 of the other packaging film 111 is fused to the third insulating element 191.

[0338] The welded portion, the first connecting portion 15, and the third connecting portion 192 are connected to form an annular sealing structure surrounding the receiving cavity 112. Optionally, during assembly, the two packaging films 111 can be welded together by heat-pressing the packaging films 111, the two packaging films 111 can be welded together with the first insulating member 14, and the two packaging films 111 can be welded together with the third insulating member 191.

[0339] In some embodiments, the metal layer 11b comprises aluminum, and the encapsulation layer 11a and the protective layer 11c comprise resin materials.

[0340] In some embodiments, the material of the encapsulation layer 11a includes polypropylene. Optionally, the encapsulation layer 11a includes a polypropylene (PP) layer and a modified polypropylene (PPa) layer disposed between the polypropylene (PP) layer and the metal layer 11b.

[0341] Modified polypropylene refers to functionalized materials that optimize the properties of ordinary polypropylene (PP) through chemical or physical means, including but not limited to grafting maleic anhydride onto the polypropylene molecular chain, introducing ethylene monomers to copolymerize with propylene, blending polypropylene with polyolefin elastomers or EPDM rubber, and adding nano-inorganic particles (such as nano-silica). Different modification methods are beneficial for specifically improving the heat-sealing properties, chemical resistance, adhesion and mechanical strength of the material.

[0342] Modified polypropylene further improves the electrolyte corrosion resistance and bonding strength of the packaging bag 11. This encapsulation layer 11a helps reduce interface leakage caused by insufficient heat seal strength.

[0343] In some embodiments, the modified polypropylene (PPa) layer comprises maleic anhydride-grafted polypropylene.

[0344] The carboxyl group (-COOH) and anhydride group (-CO-O-CO-) of maleic anhydride can chemically bond with the hydroxyl group (-OH) or aluminum oxide (Al2O3) on the surface of aluminum foil, and at the same time maintain molecular chain entanglement with the polypropylene matrix. This is beneficial to further improve the peel strength between the encapsulation layer 11a and the metal layer 11b, reduce the probability of delamination between the encapsulation layer 11a and the metal layer 11b, reduce the risk of encapsulation failure of the soft-pack battery cell 10, and further improve the reliability of the soft-pack battery cell 10.

[0345] In some embodiments, the material of the protective layer 11c includes one or more of nylon and polyethylene terephthalate. The protective layer 11c has excellent mechanical properties, which can buffer mechanical impacts during assembly, thereby reducing the risk of encapsulation failure of the pouch cell 10 and improving the reliability of the battery device 2.

[0346] In some embodiments, the packaging bag 11 is heat-sealed at 180°C-220°C.

[0347] The heat sealing temperature of the packaging bag 11 is within the above range, which helps to enhance the interfacial bonding strength, reduce the probability of delamination between the encapsulation layer 11a and the metal layer 11b during the cycle of the soft-pack battery cell 10, reduce the risk of encapsulation failure of the soft-pack battery cell 10, and improve the reliability of the soft-pack battery cell 10.

[0348] Optionally, the packaging bag 11 is heat-sealed at 200℃-210℃.

[0349] In some embodiments, the first connecting portion 15 is directly connected to the metal layer 11b, and the third connecting portion 192 is directly connected to the metal layer 11b.

[0350] In some embodiments, the thickness T4 of the first insulating member 14 is greater than the thickness T5 of the encapsulation layer 11a.

[0351] Using a relatively thin and uniform encapsulation layer 11a helps to reduce the volume and weight of the packaging bag 11 and increase the energy density of the soft-pack battery cell 10. Using a first insulating member 14 with a relatively large thickness can improve the connection strength between the first insulating member 14 and the encapsulation layer 11a.

[0352] In some embodiments, the thickness T5 of the encapsulation layer 11a is 0.2 mm to 1.0 mm.

[0353] As an example, the thickness T5 of the encapsulation layer 11a is 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, or any value between any two of the above.

[0354] In this embodiment, the thickness of the encapsulation layer 11a is set to be greater than or equal to 0.2 mm to improve the insulation effect of the encapsulation layer 11a, increase the connection strength between the encapsulation layer 11a and the first insulating member 14, and reduce the risk of seal failure. In this embodiment, the thickness of the encapsulation layer 11a is set to be less than or equal to 1.0 mm, which can reduce the difficulty of welding the encapsulation layer 11a and the first insulating member 14, reduce the amount of adhesive formed by the melting of the encapsulation layer 11a when heated, reduce the risk of adhesive overflowing outside the packaging bag 11, and improve the encapsulation effect.

[0355] In some embodiments, the thickness of the third insulating element 191 is greater than the thickness of the encapsulation layer 11a.

[0356] In some embodiments, in the first direction X, a portion of the first insulating member 14 is located between the first connecting portion 15 and the negative terminal 13.

[0357] In this embodiment, the first insulating member 14 can separate the first connecting portion 15 from the negative terminal 13, thereby reducing the impact on the connection interface between the first insulating member 14 and the negative terminal 13 during the molding process of the first connecting portion 15, reducing the risk of failure of the connection interface between the first insulating member 14 and the negative terminal 13, and improving the reliability of the soft-pack battery cell 10.

[0358] For example, during hot pressing, the portion of the first insulating member 14 that contacts the negative terminal 13 does not melt, thereby reducing the thermal impact on the connection interface between the first insulating member 14 and the negative terminal 13 and improving the sealing performance in case of failure of the connection interface between the first insulating member 14 and the negative terminal 13.

[0359] In some embodiments, in the first direction X, a portion of the third insulating member 191 is located between the third connection portion 192 and the positive terminal 16.

[0360] Figure 17 A partial cross-sectional schematic diagram of a battery device provided in some embodiments of this application; Figure 18 This is another partial cross-sectional schematic diagram of a battery device provided in some embodiments of this application.

[0361] In some embodiments, refer to Figure 17 and Figure 18 The battery device 2 includes a thermal management component 40 located on at least one side of a plurality of pouch cell 10 in the second direction Z. The thermal management component 40 is used to exchange heat with the pouch cell 10.

[0362] The thermal management component 40 is used to regulate the temperature of the pouch cell 10 to improve the cycle performance of the pouch cell 10. As an example, the thermal management component 40 has a flow channel inside, and the heat exchange medium exchanges heat with the pouch cell 10 through the thermal management component 40 when flowing through the flow channel.

[0363] In some examples, the multiple pouch cell 10 has a thermal management component 40 on only one side along the second direction Z. In other examples, the multiple pouch cell 10 has thermal management components 40 on both sides along the second direction Z.

[0364] In the second direction Z, the thermal management component 40 may be disposed opposite to the second surface 10b of a plurality of pouch cell 10.

[0365] The pouch battery cell 10 transfers heat to the thermal management component 40, thereby dissipating heat, reducing the heat accumulated inside the packaging bag 11, lowering the temperature rise of the pouch battery cell 10, reducing the decomposition and gas production of the electrolyte, slowing down the fatigue aging of the first connection part 15, reducing the risk of sealing failure of the pouch battery cell 10, and improving the reliability of the battery device 2.

[0366] In some embodiments, the battery device 2 further includes a thermally conductive adhesive 50, which is bonded to the second surface 10b and the thermal management component 40. The thermally conductive adhesive 50 can bond the pouch cell 10 to the thermal management component 40, improving the strength and rigidity of the battery device 2 and enhancing the stability of the pouch cell 10. The thermally conductive adhesive 50 has good thermal conductivity; using it to bond the second surface 10b and the thermal management component 40 can improve the heat exchange efficiency between the second surface 10b and the thermal management component 40, improve heat exchange stability, and thus improve the cycle performance of the pouch cell 10 during long-term cycling.

[0367] Multiple pouch battery cells 10 are bonded to the thermal management component 40 using thermally conductive adhesive 50, enabling integrated assembly. This eliminates the need for traditional module structures, reduces redundant components, and improves space utilization, thereby further enhancing the energy density of the battery device 2.

[0368] In some embodiments, at 85°C, the thermal conductivity of the thermally conductive adhesive 50 is greater than or equal to 0.4 W / (m·K), optionally 0.4 W / (m·K)-1.2 W / (m·K), and further optionally 0.8 W / (m·K)-1.2 W / (m·K).

[0369] The thermal conductivity of thermally conductive adhesive 50 at 85°C can be tested using methods known in the art. As an example, the transient hot disk method (Hot Disk) can be used, according to ISO 22007-2. A temperature probe with self-heating capability is placed under a sample disc with a diameter greater than 30 mm and a thickness greater than 2 mm. Standard weights from Hengzhong Company are used to press down on the sample disc. During the test, a constant heating power is applied to the nickel coil of the probe, causing its temperature to rise. Since the temperature coefficient of resistance (TCR) of nickel is linear (ΔR / R0 = αΔT), the heat loss can be obtained by measuring the change in resistance, thereby determining the thermal conductivity of the sample at 85°C.

[0370] As an example, at 85°C, the thermal conductivity of thermally conductive adhesive 50 can be selected as 0.4 W / (m·K), 0.5 W / (m·K), 0.6 W / (m·K), 0.7 W / (m·K), 0.8 W / (m·K), 0.81 W / (m·K), 0.82 W / (m·K), 0.83 W / (m·K), 0.84 W / (m·K), 0.85 W / (m·K), 0.86 W / (m·K), 0.87 W / (m·K), or 0.88 W / (m·K). 0.89 W / (m·K), 0.90 W / (m·K), 0.91 W / (m·K), 0.92 W / (m·K), 0.93 W / (m·K), 0.94 W / (m·K), 0.95 W / (m·K), 0.96 W / (m·K), 0.97 W / (m·K), 0.98 W / (m·K), 0.99 W / (m·K), 1.0 W / (m·K), 1.1 W / (m·K), 1.2 W / (m·K), or any range between the two.

[0371] The thermal conductivity of the thermal conductive adhesive 50 is within the above range, which means it has good thermal conductivity and can still conduct heat stably at high temperatures. This helps reduce the probability that the thermal conductive adhesive 50 will fail due to temperature rise, and that heat will not be able to be transferred from the pouch cell 10 to the thermal management component 40 for heat dissipation in time, resulting in heat accumulation inside the cell. This helps improve the cycle performance of the pouch cell 10 during long-cycle processes.

[0372] In some embodiments, the thermally conductive adhesive 50 is a structural adhesive.

[0373] In some embodiments, the thermally conductive adhesive 50 includes a polyurethane resin and thermally conductive filler particles dispersed in the polyurethane resin; the thermally conductive filler particles include one or more of aluminum hydroxide particles and boron nitride particles.

[0374] Thermally conductive adhesive 50, containing the above components, exhibits excellent high-temperature resistance.

[0375] In some embodiments, the battery device 2 further includes a heat-conducting plate 60 connected to the thermal management component 40, wherein at least a portion of the heat-conducting plate 60 is disposed between adjacent pouch cell 10 in a first direction X.

[0376] As an example, the heat-conducting plate 60 can be in direct contact with the first surface 10a of the pouch cell 10; alternatively, the heat-conducting plate 60 can also be bonded to the first surface 10a by an adhesive layer or double-sided adhesive.

[0377] There can be one or more heat-conducting plates 60.

[0378] The heat-conducting plate 60 can conduct heat from the pouch cell 10 to the thermal management component 40, thereby improving heat exchange efficiency, reducing the temperature of the pouch cell 10, reducing electrolyte decomposition or vaporization, slowing down fatigue aging of the first connection portion 15, reducing the risk of deformation and tearing of the first connection portion 15, and thus reducing the risk of sealing failure of the pouch cell 10. Arranging the heat-conducting plate 60 and the pouch cell 10 along the first direction X enables heat exchange between the heat-conducting plate 60 and the first surface 10a, thereby increasing the heat exchange area and improving heat exchange efficiency.

[0379] In some embodiments, in the same plane perpendicular to the first direction X, the orthographic projection of the second connecting portion 17 is located within the orthographic projection of the heat-conducting plate 60, and the orthographic projection of the fourth connecting portion 193 is located within the orthographic projection of the heat-conducting plate 60.

[0380] This embodiment can reduce the distance between the second connecting part 17 and the heat-conducting plate 60 and the fourth connecting part 193 and the heat-conducting plate 60, thereby improving the heat dissipation efficiency of the second connecting part 17 and the fourth connecting part 193, reducing the temperature rise of the second connecting part 17 and the fourth connecting part 193, reducing the decomposition or vaporization of the electrolyte, reducing the heat conducted to the first connecting part 15 and the third connecting part 192, reducing the risk of sealing failure of the soft-pack battery cell 10, and improving the reliability of the battery device 2.

[0381] In some embodiments, the battery device 2 includes a plurality of heat-conducting plates 60 arranged along a first direction X, with a pouch cell 10 disposed between adjacent heat-conducting plates 60.

[0382] Between adjacent heat-conducting plates 60, one or more pouch battery cells 10 can be arranged.

[0383] By setting multiple heat-conducting plates 60, the thermal management effect of the battery device 2 can be improved, the temperature consistency of the soft-pack battery cell 10 can be enhanced, and the risk of sealing failure of the soft-pack battery cell 10 can be reduced.

[0384] In some embodiments, the heat-conducting plate 60 includes a first plate portion 61 and two second plate portions 62, the two second plate portions 62 being arranged along a first direction X, and at least one soft-pack battery cell 10 being disposed between the two second plate portions 62 of the heat-conducting plate 60. The first plate portion 61 connects the two second plate portions 62, and the first plate portion 61 and the thermal management component 40 are arranged along a second direction Z. One end of the second plate portion 62 away from the first plate portion 61 is connected to the thermal management component 40.

[0385] The first plate portion 61 and the two second plate portions 62 form a U-shaped structure. The heat-conducting plate 60 has an opening on the side facing the thermal management component 40 along the second direction Z.

[0386] At least one pouch cell 10 is located between the second plate portion 62 of two adjacent heat-conducting plates 60.

[0387] The heat-conducting plate 60 can conduct some of the heat from the soft-pack battery cell 10 to the thermal management component 40, and can also protect and constrain the soft-pack battery cell 10, improve the stability of the soft-pack battery cell 10, reduce the movement of the soft-pack battery cell 10 when the battery device 2 is subjected to external impact, and improve the reliability and stability of the battery device 2.

[0388] In some embodiments, the thickness of the second plate portion 62 is 0.2mm-5.2mm, optionally 0.5mm-3mm, and further optionally 0.6mm-1mm. Exemplarily, the thickness of the second plate portion 62 is 0.2mm, 0.5mm, 0.8mm, 1mm, 1.2mm, 1.5mm, 1.8mm, 2mm, 2.5mm, 3mm, 3.5mm, 5mm, 4.5mm, 5mm, or 5.2mm.

[0389] In some embodiments, the thickness of the first plate portion 61 is 0.2mm-5.2mm, optionally 0.5mm-3mm, and further optionally 0.6mm-1mm. Exemplarily, the thickness of the first plate portion 61 is 0.2mm, 0.5mm, 0.8mm, 1mm, 1.2mm, 1.5mm, 1.8mm, 2mm, 2.5mm, 3mm, 3.5mm, 5mm, 4.5mm, 5mm, or 5.2mm.

[0390] In some embodiments, the second plate portion 62 is a flat plate.

[0391] In some embodiments, the second plate portion 62 is bonded to the thermal management component 40. As an example, the second plate portion 62 is bonded to the thermal management component 40 by thermally conductive adhesive 50.

[0392] In some embodiments, the thermal management component 40 has a groove (not shown) on the side facing the pouch cell 10, and the end of the second plate portion 62 near the thermal management component 40 is accommodated in the groove and connected to the thermal management component 40.

[0393] Optionally, there are multiple grooves, and each groove corresponds to a second plate portion 62.

[0394] Optionally, the groove is filled with an adhesive that bonds the thermal management component 40 and the second plate portion 62.

[0395] In some embodiments, two soft-pack battery cells 10 arranged along the first direction X are provided between the two second plate portions 62 of the heat-conducting plate 60, and two soft-pack battery cells 10 arranged along the first direction X are provided between the second plate portions 62 of two adjacent heat-conducting plates 60.

[0396] Each pouch cell 10 can exchange heat with a second plate 62.

[0397] In some embodiments, the support plate 21 is integrally formed with the thermal management component 40. The support plate 21 can serve both support and thermal management functions, which helps to reduce the number of structural components and improve the energy density of the battery device 2.

[0398] For example, the support plate 21 has flow channels inside.

[0399] In other embodiments, the thermal management component 40 is located between the support plate 21 and the plurality of pouch cell 10.

[0400] In some embodiments, the heat-conducting plate 60 is made of metal. For example, the heat-conducting plate 60 is made of aluminum or steel.

[0401] In some embodiments, the first plate portion 61 is provided with a pressure relief portion. In the event of thermal runaway of the pouch cell 10, the substances emitted by the pouch cell 10 can be discharged to the outside of the heat-conducting plate 60 via the pressure relief portion.

[0402] In some embodiments, the battery device 2 further includes a heat insulation element 70, which is provided between at least two adjacent pouch cell 10.

[0403] The heat insulation component 70 can block heat transfer between two adjacent pouch cell 10, reducing heat accumulation. In the event of thermal runaway in a pouch cell 10, the heat insulation component 70 can also slow down heat propagation.

[0404] In some embodiments, the heat insulation member 70 and the second plate portion 62 are disposed separately in the first direction X. Exemplarily, a pouch cell 10 is provided between the heat insulation member 70 and the second plate portion 62.

[0405] In some embodiments, a plurality of heat insulation members 70 and a plurality of second plate portions 62 are arranged alternately along a first direction X. A pouch cell 10 is disposed between the heat insulation members 70 and the second plate portions 62.

[0406] In some embodiments, the material of the thermal insulation component 70 is any one of nano-insulation material, glass fiber insulation material, and ceramic fiber insulation material.

[0407] In some embodiments, the thickness of the heat insulation member 70 along the first direction X is 1mm-4mm.

[0408] A second aspect of this application also provides an electrical device that uses a battery device 2 as a power source. The electrical device can be any of the aforementioned devices or systems that utilize the battery device 2.

[0409] The third aspect of this application also provides an energy storage device that uses a battery device 2 as a power source. The energy storage device can be, but is not limited to, an energy storage container, an energy storage cabinet, an energy storage power station, an energy storage battery pack, or a portable energy storage system.

[0410] Reference Figures 3 to 12 One embodiment of this application provides a battery device 2, which includes a housing 20, a battery cell assembly, and at least one connecting beam 30. A support plate 21 and a frame 22 are disposed around the outer periphery of the support plate 21, with the support plate 21 and frame 22 fixedly connected. The battery cell assembly is housed within the housing 20 and includes a plurality of pouch battery cells 10 stacked in a first direction X.

[0411] Each pouch cell 10 has a rated capacity greater than or equal to 50Ah and less than or equal to 300Ah. The surface of each pouch cell 10 includes a first surface 10a and a second surface 10b. The first surfaces 10a of multiple pouch cell 10s are arranged opposite each other along a first direction X. The support plate 21 is arranged opposite to the second surfaces 10b of multiple pouch cell 10s along a second direction Z. The area of ​​the first surface 10a is greater than the area of ​​the second surface 10b. At least one pouch cell 10 abuts against a connecting beam 30 along the first direction X. The connecting beam 30 extends along a third direction Y. At least one of the support plate 21 and the frame 22 is fixedly connected to the connecting beam 30. The first direction X, the second direction Z, and the third direction Y are perpendicular to each other.

[0412] The battery device 2 also includes a plurality of heat-conducting plates 60 arranged along a first direction X. Each heat-conducting plate 60 includes a first plate portion 61 and two second plate portions 62. The two second plate portions 62 are arranged along the first direction X, and at least one pouch cell 10 is disposed between the two second plate portions 62. The first plate portion 61 connects the two second plate portions 62, and the first plate portion 61 and the support plate 21 are arranged along a second direction Z. At least one pouch cell 10 is disposed between the second plate portions 62 of two adjacent heat-conducting plates 60.

[0413] The battery device 2 also includes thermally conductive adhesive 50, which bonds the second surface 10b and the second plate portion 62 to the support plate 21. The support plate 21 is used for heat exchange with the pouch cell 10.

[0414] The pouch cell 10 includes a packaging bag 11, an electrode assembly 12, a negative terminal 13, a positive terminal 16, a first insulating member 14, and a third insulating member 191. The electrode assembly 12 is housed within the packaging bag 11. The electrode assembly 12 includes a plurality of positive electrode plates 121 and a plurality of negative electrode plates 122, which are alternately stacked along a first direction X.

[0415] The positive electrode 121 includes a positive current collector 1211 and a positive electrode film 1212. The positive electrode film 1212 is provided on at least one side of the positive current collector 1211. The positive electrode film 1212 includes a positive electrode active material and a conductive agent. The positive electrode active material includes lithium transition metal phosphate particles. The conductive agent includes carbon nanotubes, which include one or more of single-walled carbon nanotubes, few-walled carbon nanotubes, and multi-walled carbon nanotubes.

[0416] The negative electrode 122 includes a negative electrode current collector 1221 and a negative electrode film 1222. The negative electrode film 1222 is provided on at least one side of the negative electrode current collector 1221, and the areal density of the negative electrode film 1222 is 8.4 mg / cm³. 2 -11.7mg / cm 2 The thickness of the negative electrode film 1222 is 50μm-90μm. One end of the negative terminal 13 is located inside the packaging bag 11, and the other end is located outside the packaging bag 11. The negative terminal 13 is connected to the negative current collector 1221. The first insulating member 14 surrounds the negative terminal 13 and is disposed between the negative terminal 13 and the packaging bag 11. The first insulating member 14 is sealed to the packaging bag 11 and forms a first connection part 15. The first connection part 15 is located on one side of the electrode assembly 12 along the third direction Y. The negative electrode film 1222 includes a negative electrode active material, which includes graphite. The volume distribution particle size Dv50 of the negative electrode active material is 9μm-17μm, and the volume distribution particle size Dv10 of the negative electrode active material is 3μm-9μm. The size of the first connection part 15 along the third direction Y is 2mm-6mm.

[0417] One end of the positive terminal 16 is located inside the packaging bag 11, and the other end is located outside the packaging bag 11. The positive terminal 16 is connected to the positive current collector 1211. The third insulating member 191 surrounds the positive terminal 16 and is disposed between the positive terminal 16 and the packaging bag 11. The third insulating member 191 is sealed to the packaging bag 11 and forms a third connecting part 192.

[0418] Example The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0419] Example 1 Preparation of positive electrode Lithium iron phosphate, conductive carbon black (SP), and polyvinylidene fluoride (PVDF) are mixed in a mass ratio of 97%:1%:2% in the solvent N-methylpyrrolidone to form a uniform positive electrode slurry. The positive electrode slurry is then coated onto the surface of the aluminum foil current collector and dried and cold-pressed to form a positive electrode sheet.

[0420] Preparation of negative electrode The negative electrode active material natural graphite, conductive agent conductive carbon black, binder styrene-butadiene rubber (SBR) and thickener sodium carboxymethyl cellulose (CMC) are mixed evenly in a weight percentage of 96:1:2:1 and deionized water is added. After stirring and dispersing, a negative electrode slurry is obtained. The negative electrode slurry is coated on a copper foil substrate, and after drying, compaction, slitting and sheet forming, a negative electrode sheet is obtained.

[0421] The negative electrode slurry is dried and cold-pressed to form a negative electrode film. The areal density of the negative electrode film is 10.5 mg / cm³. 2 The thickness of the negative electrode film is 72 μm.

[0422] Using a Mastersizer 3000 laser particle size analyzer, the volume distribution particle size Dv50 of the negative electrode active material was measured to be 13 μm, and the volume distribution particle size Dv10 of the negative electrode active material was measured to be 6 μm.

[0423] Preparation of the isolation component A composite slurry consisting of alumina and polyvinylidene fluoride (PVDF) polymer adhesive particles was coated on both sides of a porous polyethylene (PE) polymer film and dried to obtain a separator. The coating weight (excluding solvent) on one side of the slurry was 2.21 g / m². 2 .

[0424] Preparation of electrolyte In an argon atmosphere glove box (H2O < 0.1 ppm, O2 < 0.1 ppm), the organic solvents ethyl acetate, ethyl methyl carbonate (EMC), and ethylene carbonate (EC) are mixed thoroughly.

[0425] Lithium hexafluorophosphate was then added and dissolved in an organic solvent to achieve a concentration of 1.05 mol / L. Ethylene carbonate (VC) was then added and stirred until homogeneous to obtain the electrolyte of Example 1.

[0426] Based on the total mass of the electrolyte, the mass content of ethyl acetate is 17%, the mass content of methyl ethyl carbonate is 37%, the mass content of ethylene carbonate is 29%, and the mass content of vinylene carbonate is 1%.

[0427] Preparation of pouch cell The positive electrode, separator, and negative electrode are stacked sequentially using a stacking machine to obtain a stacked electrode assembly. The positive tab of the positive electrode is soldered to the positive terminal, and the negative tab of the negative electrode is soldered to the negative terminal. Multiple negative tabs are soldered to the negative terminal to form a second connection portion, the area S of which is 30 mm². 2 The negative terminal is encased in a first insulating element, and the positive terminal is encased in a third insulating element.

[0428] The electrode assembly is placed in a packaging bag made of flexible aluminum-plastic film, which is composed of an encapsulation layer of polypropylene, a metal layer of aluminum foil, and a protective layer of nylon. The aluminum-plastic film packaging bag is formed and trimmed using a punching machine to obtain the desired shape and size. The aluminum-plastic film is then heat-sealed, sealing it to a first insulating component to form a first connection, and then sealing it to a third insulating component to form a third connection.

[0429] After vacuum baking and settling, electrolyte is injected, and the cells are encapsulated. Then, the pouch battery cells undergo hot and cold pressing. Finally, after formation, vacuum degassing, and edge trimming, the pouch battery cells are obtained. The pouch battery cell has a length of 600mm (third direction), a width of 125mm (second direction), and a thickness of 18mm (first direction). The width W1 of the first connecting portion (i.e., the dimension of the first connecting portion in the third direction) is 2mm.

[0430] Preparation of battery devices The multiple pouch battery cells prepared above are arranged along the thickness direction and placed into the box. The pouch battery cells are then bonded to the support plate of the box and abutted against the connecting beam of the box to obtain the battery device.

[0431] Example 2-3 The battery device was prepared using a method similar to that in Example 1, except that the volume distribution particle sizes Dv50 and Dv10 of the negative electrode active material in the pouch cell were adjusted, as shown in Table 1.

[0432] Examples 4-5 The battery device was prepared using a method similar to that in Example 1, except that the width W1 of the first connecting portion in the pouch cell was adjusted, as detailed in Table 1.

[0433] Examples 6-7 The battery device was prepared using a method similar to that in Example 1, except that the area S of the second connecting portion in the pouch cell was adjusted, as detailed in Table 1.

[0434] Example 8 The battery device was prepared using a method similar to that in Example 1, except that the composition of the electrolyte in the pouch cell was adjusted. Based on the total mass of the electrolyte, the mass content of ethyl acetate was 17%, the mass content of ethyl methyl carbonate was 37.5%, the mass content of ethylene carbonate was 29%, and the mass content of vinylene carbonate was 0.5%.

[0435] Example 9 The battery device was prepared using a method similar to that in Example 1, except that the composition of the electrolyte in the pouch cell was adjusted. Based on the total mass of the electrolyte, the mass content of ethyl acetate was 17%, the mass content of methyl ethyl carbonate was 33%, the mass content of ethylene carbonate was 29%, and the mass content of vinylene carbonate was 5%.

[0436] Comparative Examples 1-2 The battery device was prepared using a method similar to that in Example 1, except that the width W1 of the first connecting portion in the pouch cell was adjusted, as detailed in Table 1.

[0437] Comparative Examples 3-4 The battery device was prepared using a method similar to that in Example 1, except that the volume distribution particle sizes Dv50 and Dv10 of the negative electrode active material in the pouch cell were adjusted, as shown in Table 1.

[0438] Test method: 1. Probability of encapsulation failure of individual pouch cells At 25°C, the battery pack cells in the battery device are charged to 3.65V at a 1C charging rate, which is equivalent to the nominal capacity of the cells. Then, they are charged at a constant voltage of 3.65V to 0.05C. After charging is completed, the charging circuit of the battery device is disconnected and left to stand for 10 minutes. Then, the battery pack cells are discharged to 2.5V at a 3C discharging rate, which is equivalent to the nominal capacity of the cells. After standing for 10 minutes, one charge-discharge cycle is recorded. The cycle is paused when the number of cycles reaches 3000. The cells in the battery device are disassembled. When misalignment or peeling occurs between the encapsulation layer and the metal layer in the packaging bag near the electrode terminals, or when a crack appears near the second connection, it is considered that the encapsulation of the cell has failed. Ten cells in each embodiment or comparative example are observed simultaneously, and the probability of encapsulation failure is calculated.

[0439] 2. Number of cycles corresponding to 80% capacity decay At 25°C, the battery pack cells in the device are charged to 3.65V at a charging rate of 0.5C, which is equivalent to the nominal capacity of the individual cells. Then, they are charged at a constant voltage of 3.65V to 0.05C. After charging is complete, the charging circuit of the battery pack is disconnected and left to stand for 10 minutes. Then, the battery pack cells are discharged to 2.5V at a discharge rate of 1C, which is equivalent to the nominal capacity of the individual cells. After standing for 10 minutes, one charge-discharge cycle is counted as one cycle. The test is stopped when the capacity of the battery pack is reduced to 80% of the nominal capacity. This number of cycles is recorded as the number of cycles corresponding to the 80% capacity reduction.

[0440] 3. Volumetric energy density of a single pouch cell At 25°C, the prepared pouch cell was charged to 3.65V at a constant current of 0.33C, then charged to 0.05C at a constant voltage of 3.65V, and finally discharged to 2.5V at a constant current of 0.33C. The discharge energy A0 Wh was recorded. The volume of the pouch cell is 600mm × 125mm × 18mm = 1.35L. The volumetric energy density of the pouch cell is (A0 / 1.35) Wh / L.

[0441] Test Results The test results are shown in Table 1.

[0442] Table 1

[0443] Referring to Examples 1-9 and Comparative Examples 3-4, the embodiments of this application set the volume distribution particle size Dv50 of the negative electrode active material to be less than or equal to 17 μm and the volume distribution particle size Dv10 of the negative electrode active material to be less than or equal to 9 μm. This is beneficial for shortening the ion intercalation path, reducing the internal resistance of the pouch cell, reducing heat generation, lowering the temperature rise of the pouch cell, and reducing the heat conducted to the first connection part. The embodiments of this application set the volume distribution particle size Dv50 of the negative electrode active material to be greater than or equal to 9 μm and the volume distribution particle size Dv10 of the negative electrode active material to be greater than or equal to 3 μm. This can reduce the content of negative electrode active material with a particle size less than 9 μm, especially reducing the content of negative electrode active material with a particle size less than 3 μm. This is beneficial for reducing the active sites of the negative electrode active material, reducing the specific surface area of ​​the negative electrode active material, reducing the decomposition and gas generation of the electrolyte, reducing the internal pressure of the pouch cell during cycling, and reducing the force on the first connection part. In this embodiment, the volume distribution particle size Dv50 of the negative electrode active material is set to 9μm-17μm, and the volume distribution particle size Dv10 of the negative electrode active material is set to 3μm-9μm. This is beneficial to balance the internal heat generation and gas generation of the soft-pack battery cell, balance the force and heat effects on the first connection part, improve the cycle performance of the soft-pack battery cell, and enhance the cycle life of the soft-pack battery cell.

[0444] Referring to Examples 1-9 and Comparative Example 1, in this embodiment of the application, the width W1 of the first connection portion is set to be greater than or equal to 2mm, which can improve the sealing strength. This reduces the problem of easy sealing failure of the soft-pack battery cell near the first connection portion when Dv50 is 9μm-17μm and Dv10 is 3μm-9μm, thereby improving the reliability of the battery device.

[0445] Referring to Examples 1-9 and Comparative Example 2, in this embodiment of the application, the width W1 of the first connecting part is set to be less than or equal to 6mm. This can reduce the space occupied by the first connecting part in the third direction, improve space utilization, increase the energy density of the battery device, shorten the conductive path of the electrode terminals, reduce the internal resistance of the soft-pack battery cell, and improve the cycle life of the soft-pack battery cell and the battery device.

[0446] Referring to Examples 1-9 and Comparative Examples 1-4, the present application embodiments set the volume distribution particle size Dv50 of the negative electrode active material to 9μm-17μm, the volume distribution particle size Dv10 of the negative electrode active material to 3μm-9μm, and the width W1 of the first connection portion to 2mm-6mm, which is beneficial to balance the reliability, cycle life and energy density of the battery device to a certain extent.

[0447] Referring to Examples 1, 6, and 7, setting the area S of the second connection portion to be greater than or equal to 20 mm² can reduce the resistance of the second connection portion, improve its current carrying capacity, reduce heat generation, lower its temperature rise, reduce the risk of electrolyte decomposition, reduce heat conducted to the first connection portion, slow down fatigue aging of the first connection portion, reduce the risk of sealing failure of the pouch cell near the first connection portion, and improve the cycle life of the pouch cell. Setting the area S of the second connection portion to be less than or equal to 60 mm² can reduce the space occupied by the second connection portion, thereby reducing the size requirements of the negative electrode tab and negative terminal, and reducing the impact of increasing the area of ​​the second connection portion on the energy density of the pouch cell.

[0448] Referring to Examples 1, 8, and 9, by setting the mass percentage of vinylene carbonate in the electrolyte to 0.5%-5%, it is beneficial to improve the density and uniformity of the solid electrolyte interphase (SEI) film formed on the surface of the negative electrode, reduce electrolyte decomposition and side reactions, reduce the risk of sealing failure of the pouch cell, and improve the cycle life and reliability of the pouch cell.

[0449] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0450] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features. However, these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A battery device, characterized in that, include: The housing includes a support plate and a frame surrounding the outer periphery of the support plate, wherein the support plate is fixedly connected to the frame; Multiple pouch battery cells are stacked and housed in the housing in a first direction. The rated capacity of each pouch battery cell is greater than or equal to 50Ah and less than or equal to 300Ah. The surface of each pouch battery cell includes a first surface and a second surface. The first surfaces of the multiple pouch battery cells are arranged opposite to each other along the first direction. The support plate is arranged opposite to the multiple second surfaces along a second direction. The area of ​​the first surface is greater than the area of ​​the second surface. At least one connecting beam, at least one of the soft-pack battery cells abutting against the connecting beam along the first direction, the connecting beam extending along a third direction, at least one of the support plate and the frame being fixedly connected to the connecting beam, the first direction, the second direction and the third direction being perpendicular to each other; The soft-pack battery cell includes a packaging bag, an electrode assembly, a negative terminal, and a first insulating component. The electrode assembly is housed within the packaging bag and includes a positive electrode and a negative electrode. The positive electrode includes a positive current collector and a positive electrode film. The positive electrode film is disposed on at least one side of the positive current collector and includes a positive electrode active material, which includes lithium transition metal phosphate particles. The negative electrode includes a negative current collector and a negative electrode film. The negative electrode film is disposed on at least one side of the negative current collector and has an areal density of 8.4 mg / cm³. 2 -11.7mg / cm 2 The thickness of the negative electrode film is 50μm-90μm. One end of the negative terminal is located inside the packaging bag, and the other end is located outside the packaging bag. The negative terminal is connected to the negative current collector. The first insulating member surrounds the negative terminal and is disposed between the negative terminal and the packaging bag. The first insulating member is sealed to the packaging bag and forms a first connection part. The first connection part is located on one side of the electrode assembly along the third direction. The negative electrode film includes a negative electrode active material, which includes graphite. The volume distribution particle size Dv50 of the negative electrode active material is 9μm-17μm, and the volume distribution particle size Dv10 of the negative electrode active material is 3μm-9μm. The size of the first connection part along the third direction is 2mm-6mm.

2. The battery device according to claim 1, characterized in that, The volume distribution particle size Dv50 of the negative electrode active material is 11μm-15μm, and the volume distribution particle size Dv10 of the negative electrode active material is 5μm-7μm.

3. The battery device according to claim 1, characterized in that, The soft-pack battery cell also includes an electrolyte contained in the packaging bag. The electrolyte includes additives, including vinylene carbonate, and the mass percentage of vinylene carbonate in the electrolyte is 0.5%-5%.

4. The battery device according to claim 1, characterized in that, The pouch battery cell also includes an electrolyte contained in the packaging bag, the electrolyte comprising a chain ester solvent, the chain ester solvent comprising 40% to 60% by mass in the electrolyte.

5. The battery device according to claim 1, characterized in that, The pouch battery cell also includes an electrolyte contained in the packaging bag, the electrolyte comprising dimethyl carbonate, wherein the mass percentage of dimethyl carbonate in the electrolyte is 10% to 40%.

6. The battery device according to claim 1, characterized in that, The positive electrode film layer includes a conductive agent, which includes carbon nanotubes, and the carbon nanotubes include one or more of single-walled carbon nanotubes, few-walled carbon nanotubes, and multi-walled carbon nanotubes.

7. The battery device according to claim 6, characterized in that, The carbon nanotubes in the positive electrode film layer account for 0.3%-0.7% of the total mass.

8. The battery device according to claim 1, characterized in that, The electrode assembly includes an isolator disposed between the positive electrode and the negative electrode; The separator includes a base film, an inorganic particle layer, and an adhesive layer. The inorganic particle layer is provided on at least one side of the base film, and the adhesive layer is provided on at least one side of the inorganic particle layer away from the base film. The adhesive layer is a continuous layer with a porous structure and includes a vinylidene fluoride polymer.

9. The battery device according to claim 8, characterized in that, The vinylidene fluoride polymer includes one or more of vinylidene fluoride homopolymers and copolymers of vinylidene fluoride and hexafluoropropylene.

10. The battery device according to claim 1, characterized in that, The ratio of the thickness of the negative electrode current collector to the thickness of the negative electrode sheet is 3%-7%.

11. The battery device according to claim 1, characterized in that, The negative electrode current collector includes a negative electrode current collector and a negative electrode tab. The negative electrode tab is located on the side of the negative electrode current collector closer to the negative electrode terminal. At least a portion of the negative electrode film is disposed in the negative electrode current collector, and at least a portion of the negative electrode tab is not provided with the negative electrode film. Multiple negative electrode tabs are welded to the negative terminal to form a second connection portion, and the second connection portion is spaced apart from the first connection portion.

12. The battery device according to claim 11, characterized in that, The area of ​​the second connecting part is 20mm. 2 Up to 60mm 2 .

13. The battery device according to claim 11 or 12, characterized in that, The first insulating member extends inward beyond the first connecting portion at its end near the negative current collector in a third direction; In the third direction, the first insulating member and the second connecting portion are spaced apart.

14. The battery device according to claim 11, characterized in that, The plurality of negative tabs and the negative terminal are stacked along the first direction; the pouch cell also includes a second insulating member, which is disposed on the side of the plurality of negative tabs away from the negative terminal and covers the second connection portion in the first direction.

15. The battery device according to claim 11, characterized in that, The second connection portion includes a plurality of first weld portions; and / or The second connecting portion includes a linear first weld portion.

16. The battery device according to claim 11, characterized in that, Multiple negative electrode tabs are welded together to form a second welded section; A portion of the second welded part is welded to the negative terminal to form the second connection part.

17. The battery device according to claim 1, characterized in that, The packaging bag includes a stacked encapsulation layer, a metal layer, and a protective layer. The encapsulation layer is located on the surface of the metal layer facing the electrode assembly. The encapsulation layer is fused to the first insulating member and forms the first connection portion.

18. The battery device according to claim 17, characterized in that, The thickness of the first insulating element is greater than the thickness of the encapsulation layer.

19. The battery device according to claim 17 or 18, characterized in that, The metal layer comprises aluminum, and the encapsulation layer and the protective layer comprise resin materials.

20. The battery device according to claim 17, characterized in that, The encapsulation layer is made of polypropylene, and the protective layer is made of one or more of nylon and polyethylene terephthalate.

21. The battery device according to claim 1, characterized in that, In the second direction, the ratio of the width of the negative terminal to the width of the packaging bag is 0.2-0.

5.

22. The battery device according to claim 1, characterized in that, The dimension L0 of the soft-pack battery cell in the third direction is 500mm-1250mm; the dimension W0 of the soft-pack battery cell in the second direction is 100mm-150mm; and the dimension H0 of the soft-pack battery cell in the first direction is 14mm-22mm.

23. The battery device according to claim 1, characterized in that, The electrode assembly has a stacked structure.

24. The battery device according to claim 1, characterized in that, The battery device includes a thermal management component located on at least one side of the plurality of pouch cell batteries in the second direction, the thermal management component being used for heat exchange with the pouch cell batteries.

25. The battery device according to claim 24, characterized in that, It also includes a thermally conductive adhesive, which is bonded to the second surface and the thermal management component.

26. The battery device according to claim 24 or 25, characterized in that, It also includes a heat-conducting plate connected to the thermal management component, wherein at least a portion of the heat-conducting plate is disposed between adjacent pouch cell units in the first direction.

27. The battery device according to claim 26, characterized in that, The battery device includes a plurality of heat-conducting plates arranged along the first direction, with the soft-pack battery cells disposed between adjacent heat-conducting plates.

28. The battery device according to claim 27, characterized in that, The heat-conducting plate includes a first plate portion and two second plate portions. The two second plate portions are arranged along a first direction. At least one of the soft-pack battery cells is disposed between the two second plate portions of the heat-conducting plate. The first plate portion is connected to the two second plate portions. The first plate portion and the thermal management component are arranged along a second direction. The end of the second plate portion away from the first plate portion is connected to the thermal management component.

29. The battery device according to claim 24, characterized in that, The support plate is integrally formed with the thermal management component; or The thermal management component is located between the support plate and the plurality of pouch cell units.

30. An electrical device, characterized in that, The battery device includes any one of claims 1 to 29, the battery device being used to provide electrical energy.

31. An energy storage device, characterized in that, The battery device includes any one of claims 1 to 29, the battery device being used for storing electrical energy.

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