Battery pack and energy storage device

Abstract

The utility model provides a battery pack and an energy storage device, the battery pack comprises a shell and a plurality of battery cells accommodated in the shell, each battery cell comprises a shell, a top cover hermetically covering the shell, and a pole piece and electrolyte accommodated in a sealed cavity enclosed by the shell and the top cover; the battery cell further comprises an insulating layer covering the outer surface of the shell and the outer surface of the top cover, and the insulating layer covering the outer surface of the shell and the outer surface of the top cover is of an integrated structure and is exposed in the shell. According to the battery cell, the insulating layer can be effectively prevented from warping, and the shell and the top cover are not exposed, so that the problem of electric connection between the negative pole and the shell is avoided, the problem of corrosion of the shell of the battery cell can be effectively solved, and leakage of electrolyte of the battery cell is avoided. And the problem of shell corrosion caused by short circuit of the shell of the battery cell is effectively solved.

Description

Technical Field

[0001] The present application relates to the technical field of batteries, and in particular to a battery pack and an energy storage device. Background Art

[0002] Battery cells are widely used in many industries, such as energy storage and automobile fields. However, in the battery cells of related technologies, the battery cell shell and the negative pole are often short-circuited during use, which leads to corrosion of the battery cell shell and leakage. In order to reduce the short-circuit of the shell from its outside, some related technologies insulate the battery cell shell by wrapping a blue film on the outside of the battery cell shell. However, during use, the starting edge of the blue film and the overlapping part of the blue film when wrapping the shell often warp up, causing the shell to be exposed. The exposed shell will cause the shell to be short-circuited and corroded. Therefore, there is an urgent need for a solution to solve the problem of shell corrosion caused by short circuit in the battery cell shell. Utility Model Content

[0003] The embodiments of the present application provide a battery pack and an energy storage device to effectively solve the problem of shell corrosion caused by short circuit in the shell of the battery cell.

[0004] In a first aspect, an embodiment of the present application provides a battery pack, comprising a shell and a plurality of battery cells accommodated in the shell, the battery cells comprising a shell, a top cover sealed on the shell, and a pole piece and an electrolyte accommodated in a sealed cavity surrounded by the shell and the top cover; the battery cells also include an insulating layer coated on the outer surface of the shell and the outer surface of the top cover, the insulating layer coated on the outer surface of the shell and the outer surface of the top cover is an integrated structure and is exposed in the shell.

[0005] In the present embodiment, the insulating layer is coated on the outer surface of the shell and the outer surface of the top cover, and the insulating layer coated on the outer surface of the shell and the outer surface of the top cover is an integrated structure, so that the insulating layer coated on the shell and the top cover does not have a butt edge between the top cover and the shell, thereby effectively reducing or completely avoiding areas prone to warping. For example, at the position where the top cover and the shell are connected, since the insulating layer is an integrated structure, there is no connection point, so the problem of warping will not occur, and the warping of the insulating layer can be effectively avoided, and the shell and the top cover will not be exposed, so the problem of electrical connection between the negative electrode column and the shell will not occur, thereby effectively solving the problem of corrosion of the shell of the battery cell and avoiding leakage of the electrolyte of the battery cell.

[0006] In addition, since the insulating layer covering the outer surface of the shell and the top cover is exposed in the outer shell of the battery pack, and since the insulating layer in this embodiment is not prone to warping, there is no need to uniformly pack multiple battery cells into one plastic shell. This ensures that the insulating layer does not warp and can effectively ensure the insulation performance of the shell and the top cover, while also ensuring that the battery cells have sufficient heat dissipation performance.

[0007] In addition, since the insulating layer covering the outer surface of the shell and the top cover is an integrated structure, the problem of warping can be effectively avoided, so there is no need to overlap the blue film in the area prone to warping like the blue film, thereby effectively reducing the thickness of the insulating layer to improve the heat dissipation capacity of the battery cell.

[0008] In some embodiments, the shell includes a bottom wall and a plurality of side walls connected to the bottom wall, wherein the bottom wall and the top cover are arranged opposite to each other, and the top cover, the bottom wall and the plurality of side walls are connected to form a sealed cavity.

[0009] In some embodiments, the insulating layer is coated on the bottom wall and the plurality of side walls. In some implementations, the insulating layer completely coats the outer surface of the housing, so as to ensure the insulation performance of the housing without dead angles through the insulating layer.

[0010] In some embodiments, the insulating layer and the shell are an integrated structure, and the insulating layer and the top cover are an integrated structure. It can be understood that the insulating layer and the shell are an integrated structure, that is, the insulating layer is directly formed on the outer surface of the shell, so that the insulating layer can form an integrated structure with the shell. Similarly, the insulating layer and the top cover are an integrated structure, that is, the insulating layer is directly formed on the outer surface of the top cover, so that the insulating layer can form an integrated structure with the shell. In this embodiment, since the insulating layer and the shell are an integrated structure, and the insulating layer and the top cover are an integrated structure, it is possible to avoid the insulating layer from warping relative to the shell and the top cover, and the insulating layer can stably maintain the insulation performance of the shell and the top cover, thereby preventing the shell from being corroded by negative shorting. Moreover, by directly forming the insulating layer on the shell and the top cover, it is also convenient to form an insulating layer of an integrated structure, so that the difficulty of setting the insulating layer as an integrated structure can be appropriately reduced.

[0011] In some embodiments, the insulating layer is integrally injection molded on the outer surface of the shell and the outer surface of the top cover by injection molding. The one-piece injection molding method can form a convenient insulating layer on the outer surface of the shell and the outer surface of the top cover at the same time, and can ensure the integrated structure of the insulating layer and the integrity of the insulating layer.

[0012] In some embodiments, the insulating layer can be formed by spraying the material constituting the insulating layer on the outer surface of the shell and the outer surface of the top cover. Forming the insulating layer on the shell and the top cover by spraying can also ensure the integrated structure of the insulating layer and the integrity of the insulating layer.

[0013] In some embodiments, the connection between the insulating layer and the shell is a sealed connection. In this embodiment, since the connection between the insulating layer and the shell is a sealed connection, the outer surface of the shell is sealed and isolated from the air outside the shell, so that even if the position where the insulating layer is wrapped on the top cover is damaged due to special reasons, and the negative pole and the top cover are overlapped by conductive debris, etc., it will not cause corrosion of the shell. This is because the connection between the insulating layer and the shell is a sealed connection, and the insulating layer has a sealing effect on the shell, so that the outside air will not contact the shell, so that the shell embedded with cations can be prevented from contacting with the air outside the battery cell and pulverizing, so that leakage of the shell can be avoided, and the electrolyte cannot pass through the shell to reach the insulating layer and corrode and destroy the insulating layer.

[0014] In some embodiments, the connection between the insulating layer and the top cover is a sealed connection. In this embodiment, during the transportation of the battery pack, the electrolyte of the battery cell can come into contact with the top cover due to shaking or uneven placement, and the insulating layer on the shell is damaged, and the damaged shell is short-circuited with the negative pole or other charged shells of the battery cell, so as to prevent the top cover of the battery cell from leaking. Specifically, it is because the insulating layer isolates the top cover from the outside air, so even if the top cover is electronically and ionically conductive at the same time, the insulating layer isolates the top cover from the outside air and will not powderize, so that the top cover will not leak.

[0015] In some embodiments, a pole is provided on the top cover, and an opening is provided on the portion of the top cover covered by the insulating layer, through which the pole passes. The pole is exposed through the opening to facilitate connection with other battery cells in series or in parallel.

[0016] In some embodiments, the top cover is provided with a fixing hole for mounting the pole, and the battery pack further includes a sealing ring, which is disposed between the radial outer peripheral surface of the pole and the inner peripheral surface of the fixing hole, and a portion of the sealing ring protrudes from the top cover, and the inner wall of the opening of the insulating layer surrounds the outer peripheral surface of the sealing ring. In this embodiment, since the insulating layer surrounds the outer peripheral surface of the sealing ring, the insulating layer and the outer peripheral surface of the sealing ring are seamlessly connected, thereby preventing debris from connecting to the top cover through the gap between the insulating layer and the outer peripheral surface of the sealing ring, and ensuring that the insulating layer insulates and protects the top cover and the shell in all directions without dead angles, so as to prevent the shell or top cover of the battery cell from being corroded and leaking.

[0017] In some embodiments, the insulating layer is also provided with openings for exposing the QR code of the battery cell, explosion-proof valves, and shell pressure test points, so that the QR code of the battery cell and the shell pressure test can be used normally.

[0018] In some embodiments, the thickness of the insulating layer is 20 μm-2 mm. Within this range, the insulating layer has sufficient strength to effectively avoid being worn and causing the shell to be exposed, and at the same time, within this range, effective insulation performance can be provided to the shell and the top cover to avoid short circuit between the shell and the top cover and the negative pole.

[0019] In some embodiments, the insulating layer includes a thermally conductive material and an insulating material. In this embodiment, since the insulating layer includes a thermally conductive material and an insulating material, the thermal conductivity of the insulating layer can be effectively improved to improve the heat dissipation performance of the battery cell, so that the insulation capacity and heat dissipation of the battery cell can be effectively improved.

[0020] In some embodiments, the thermally conductive material is doped with one of a polyethylene layer, a polyvinyl chloride layer, a polypropylene layer, a polytetrafluoroethylene layer, a polycarbonate layer, a polyethylene terephthalate layer, a polyphenylene sulfide layer, and a polyamide layer.

[0021] In some embodiments, the thermal conductivity of the insulating layer is greater than xx. In this embodiment, since the thermal conductivity of the insulating layer is greater than 0.5W / (mk), the heat dissipation performance of the insulating layer can effectively meet the use requirements.

[0022] In some embodiments, the battery cell further includes an outer layer, which is coated on the outer surface of the insulating layer. The outer layer has stronger wear resistance than the insulating layer, so that by coating the outer layer on the outer surface of the insulating layer, the insulating layer can be protected from being worn and damaged by the outer layer, thereby ensuring that the insulating layer can stably maintain insulation protection for the shell to prevent the shell from contacting with external conductive objects, such as preventing conductive debris from overlapping the negative electrode column with the shell.

[0023] In some embodiments, the outer layer includes a bottom wall and a plurality of side walls connected to the bottom wall, wherein the bottom wall of the outer layer corresponds to the bottom wall of the shell, and the side walls of the outer layer correspond to the side walls of the shell. The portion of the insulating layer located on the bottom wall of the shell is completely covered by the bottom wall of the outer layer, the portion of the insulating layer located on the side wall of the shell is covered by the outer layer, the height of the side wall of the outer layer is higher than the height of the electrolyte in the shell, and the insulating layer is sealed and connected to the outer surface of the shell. In this embodiment, since the insulating layer also has a sealing function, and the height of the side wall of the outer layer is higher than the height of the electrolyte, the insulating layer corresponding to the portion of the shell in contact with the electrolyte can be effectively protected by the outer layer to avoid the insulating layer corresponding to the portion of the shell in contact with the electrolyte from being worn out. As long as the insulating layer corresponding to the portion of the shell in contact with the electrolyte can be effectively protected by the outer layer, the portion of the shell in contact with the electrolyte can be sealed and isolated from the external air by the insulating layer, so that the portion of the shell in contact with the electrolyte will never be powdered, and there will be no leakage.

[0024] In a second aspect, an embodiment of the present application provides an energy storage device, comprising a cabinet and a plurality of battery packs as described in any one of the first aspects above, wherein the plurality of battery packs are disposed in the cabinet. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below.

[0026] Figure 1 A simple structural schematic diagram of an energy storage device provided in an embodiment of the present application;

[0027] Figure 2 A schematic diagram of the structure of a battery pack provided in an embodiment of the present application;

[0028] Figure 2A It is a partial structural schematic diagram of a battery pack in the related art;

[0029] Figure 3 A schematic diagram of the structure of a battery cell provided in an embodiment of the present application;

[0030] Figure 4 for Figure 3 An exploded schematic diagram of a battery cell in an embodiment;

[0031] Figure 5 Figure 3 A cross-sectional view of a battery cell in an embodiment;

[0032] Figure 6 for Figure 5 A local enlarged schematic diagram of the middle A;

[0033] Figure 7 A schematic diagram of the structure of another battery cell provided in an embodiment of the present application. Description of the drawings:

[0035] 1. Energy storage device; 2. Cabinet; 3. Battery pack; 4. Shell; 5. Battery cell; 6. Sealed cavity; 7. Blue film; 8. Plastic shell;

[0036] 10. Shell; 11. Bottom wall of shell; 12. Side wall of shell; 20. Top cover; 21. Fixing hole; 31. Electrolyte; 32. Pole piece; 40. Insulation layer;

[0037] 50, pole; 52, sealing ring; 521, inner circumference of the sealing ring; 522, outer circumference of the sealing ring;

[0038] 60. Explosion-proof valve;

[0039] 70. outer layer; 71. bottom wall of the outer layer; 72. side wall of the outer layer. DETAILED DESCRIPTION

[0040] The following first explains some terms involved in the embodiments of the present application.

[0041] The terms "first", "second", "third", "fourth", etc. in the specification and claims of the embodiments of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can, for example, be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0042] In this specification, the terms "perpendicular", "parallel", etc. are explained.

[0043] Vertical: The verticality defined in this application is not limited to an absolute vertical intersection relationship (angle of 90 degrees). It allows for non-absolute vertical intersection relationships caused by factors such as assembly tolerance, design tolerance, and influence of structural flatness. It also allows for errors in a small angle range. For example, the assembly error range of 80 to 100 degrees can be understood as a vertical relationship.

[0044] Parallelism: The parallelism defined in this application is not limited to absolute parallelism. This definition of parallelism can be understood as basic parallelism, which allows for situations where the absolute parallelism is not caused by factors such as assembly tolerance, design tolerance, and influence of structural flatness. These situations will lead to the sliding fitting part and the first door panel not being absolutely parallel, but this application also defines this situation as parallelism.

[0045] Figure 1 A simple structural schematic diagram of an energy storage device 1 provided in an embodiment of the present application.

[0046] Reference Figure 1 The energy storage device 1 includes a cabinet 2 and a plurality of battery packs 3 disposed in the cabinet 2. The plurality of battery packs 3 are stacked in the cabinet 2. The plurality of battery packs 3 can store or output electrical energy.

[0047] To facilitate understanding of the energy storage device 1 provided in the embodiment of the present application, its application scenario is first introduced below. The energy storage device 1 is a system that can store electrical energy through a certain medium and release the stored energy to generate electricity when needed. It can be used as a load balancing device and a backup power supply in industrial and commercial parks, large ground power supply stations, or photovoltaic storage systems. The application of the energy storage device 1 is briefly described using the photovoltaic storage system scenario as an example. The photovoltaic storage system generally includes a photovoltaic module, an energy storage converter, an energy storage device 1, and a grid-connected inverter. Among them, the photovoltaic module can convert light energy into electrical energy in the form of direct current and output it to the grid-connected inverter; the grid-connected inverter can convert electrical energy in the form of direct current into electrical energy in the form of alternating current, and transmit the electrical energy in the form of alternating current to the grid, thereby realizing the grid connection of the photovoltaic storage system. The energy storage device 1 can store a portion of the electrical energy output by the photovoltaic inverter when the electrical energy generated by the photovoltaic module exceeds the demand for electrical energy of the grid, and when the electrical energy output by the photovoltaic module cannot meet the demand for electrical energy of the grid, the stored electrical energy is output to the grid to provide a more stable DC source for the grid. The energy storage converter can convert the grid voltage into the supply voltage of the energy storage device 1, or convert the voltage stored in the energy storage device 1 into the grid voltage and output it to the grid.

[0048] In addition, according to the different power consumption requirements of the application scenarios of the energy storage device 1, the energy storage device 1 can also be divided into a module-level energy storage device 1, a cabinet-level energy storage device 1 and a container-level energy storage device 1.

[0049] Figure 2 A schematic diagram of the structure of a battery pack 3 provided in an embodiment of the present application. Figure 2 The battery pack 3 in the embodiment can be used not only Figure 1 The energy storage device 1 in the embodiment can also be applied to the vehicle field or other fields that require the use of a battery pack 3 .

[0050] Reference Figure 2 The battery pack 3 includes a housing 4 and a plurality of battery cells 5 in the housing 4, wherein the plurality of battery cells 5 are arranged in the housing 4. It can be understood that the plurality of battery cells 5 can be arranged in one row or in multiple rows.

[0051] In some implementations, the plurality of battery cells 5 are connected in series. In some other implementations, the plurality of battery cells 5 may be connected in parallel, or some of the battery cells 5 may be connected in series and some of the battery cells 5 may be connected in parallel.

[0052] In some embodiments, the shell of the battery cell 5 is a metal shell, such as an aluminum shell.

[0053] In some embodiments, when the shell of the battery cell 5 includes an aluminum shell, in order to improve the problem that the aluminum shell is easily corroded by the electrolyte 31 in the battery cell 5, the aluminum shell is charged, which can improve the problem of cations in the electrolyte 31 being embedded in the aluminum shell. For example, for the lithium-ion battery cell 5, the problem of lithium ions being embedded in the aluminum shell to form lithium-intercalated aluminum compounds can be effectively improved. It is understandable that in some other embodiments, the shell can also be an aluminum alloy shell, stainless steel or other metal shell.

[0054] In some embodiments, the battery core 5 is substantially in the shape of a rectangular parallelepiped. Of course, in other embodiments, the battery core 5 may also be in other shapes.

[0055] Figure 2A It is a partial structural schematic diagram of a battery pack 3 in the related art.

[0056] It is understandable that, referring to Figure 2A When the shell of the battery cell 5 contacts its own negative pole or an adjacent negative pole, a negative short will occur, and the shell will be easily corroded and leak. In order to prevent the shell from having a negative short, in some embodiments, the shell is wrapped with a blue film 7, and an insulating top patch is attached to the top cover. However, during use, the top patch often warps up, exposing the top cover. It also often happens that the starting edge of the blue film 7 and the overlapping part of the blue film 7 when wrapping the shell are warped, causing the shell to be exposed. In addition, the blue film 7 is also easily damaged by friction, causing the shell to be exposed. Therefore, the solution of the blue film 7 and the top patch in the related art cannot effectively solve the problem of shell corrosion caused by a short circuit between the shell and the negative pole.

[0057] In order to solve the problem of warping of the blue film 7, in some embodiments, the battery pack 3 further includes a plastic shell 8, and multiple battery cells 5 are wrapped with the blue film 7 and assembled together into the plastic shell 8 to further improve the insulation of the shell and the top cover of the battery cells 5. However, this method is not only complicated to assemble, but also has poor heat dissipation performance and occupies a large volume, which is not conducive to improving the energy density of the battery pack 3.

[0058] Figure 3 A schematic diagram of the structure of a battery cell 5 provided in an embodiment of the present application; Figure 4 for Figure 3 An exploded schematic diagram of the battery cell 5 in the embodiment. Figure 3 The battery cell 5 in the embodiment can be applied to Figure 2 In the battery pack 3 in the embodiment.

[0059] Reference Figure 3 and Figure 4The battery cell 5 includes a shell 10, a top cover 20, an electrolyte 31 and a pole piece 32. The top cover 20 is sealed on the shell 10 to form a sealed cavity 6. The pole piece 32 is accommodated in the sealed cavity 6. The electrolyte 31 of the battery cell 5 is also accommodated in the sealed cavity 6.

[0060] The shell 10 includes an opening, and the top cover 20 is sealed on the opening of the shell 10 , thereby forming a sealed cavity 6 by the top cover 20 and the shell 10 .

[0061] The top cover 20 is used to be provided with poles 50 , such as a positive pole and a negative pole. The top cover 20 may also be provided with an explosion-proof valve 60 .

[0062] The top cover 20 is also provided with a two-dimensional code and a shell pressure test point, etc. Of course, in some other embodiments, the two-dimensional code and the pressure test point may also be provided on the shell 10.

[0063] The electrode sheet 32 ​​includes a positive electrode sheet 32, a negative electrode sheet 32, and a separator between the positive electrode sheet 32 ​​and the negative electrode sheet 32. The positive electrode sheet 32, the negative electrode sheet 32, and the separator can be wound to form a core, or can be stacked to form a core. The positive electrode sheet 32 ​​is connected to the positive electrode column, and the negative electrode sheet 32 ​​is connected to the negative electrode column.

[0064] In order to solve the problem of warping and easy damage of the blue film 7 and the top sticker in the related art, in some embodiments, the battery cell 5 further includes an insulating layer 40 coated on the outer surface of the shell 10 and the outer surface of the top cover 20. The insulating layer 40 coated on the outer surface of the shell 10 and the outer surface of the top cover 20 is an integrated structure and is exposed in the shell 4. It can be understood that the insulating layer 40 in this embodiment is an integrated structure, which is different from Figure 2A The blue film 7 in the coating often needs to be butted against each other, or there will be overlapping areas (such as Figure 2A The insulating layer 40 in this embodiment is an integrated structure, so there will be no overlapping areas and no butt joint edges between the surfaces.

[0065] In the present embodiment, the insulating layer 40 is coated on the outer surface of the shell 10 and the outer surface of the top cover 20, and the insulating layer 40 coated on the outer surface of the shell 10 and the outer surface of the top cover 20 is an integrated structure, so that the insulating layer 40 coated on the shell 10 and the top cover 20 does not have a butt edge between the top cover 20 and the shell 10, thereby effectively reducing or completely avoiding areas prone to warping. For example, at the position where the top cover 20 and the shell 10 are connected, since the insulating layer 40 is an integrated structure, there is no connection point, so the problem of warping will not occur, and the warping of the insulating layer 40 can be effectively avoided, and the shell 10 and the top cover 20 will not be exposed, so that the problem of electrical connection between the negative electrode column and the shell 10 will not occur, thereby effectively solving the corrosion problem of the shell 10 of the battery cell 5 and avoiding the leakage of the electrolyte 31 of the battery cell 5.

[0066] In addition, since the insulating layer 40 covering the outer surface of the shell 10 and the top cover 20 is exposed in the outer shell 4 of the battery pack 3, that is, since the insulating layer 40 in this embodiment is not easy to be lifted, it is no longer necessary to install the battery cell 5 in a similar Figure 2A In the plastic shell 8 of the embodiment, it is possible to ensure that the insulating layer 40 does not warp and the insulation performance of the shell 10 and the top cover 20 is effectively guaranteed, while at the same time ensuring that the battery cell 5 has sufficient heat dissipation performance.

[0067] In addition, since the insulating layer 40 covering the outer surface of the housing 10 and the top cover 20 is an integrated structure, the problem of warping can be effectively avoided, thereby eliminating the need for Figure 2A The blue film 7 is overlapped and arranged in the area which is easy to warp, like the blue film 7 in FIG. 4 , so that the thickness of the insulating layer 40 can be effectively reduced to improve the heat dissipation capacity of the battery cell 5 .

[0068] In some embodiments, the shell 10 includes a bottom wall 11 and multiple side walls 12 connected to the bottom wall 11, wherein the bottom wall 11 and the top cover 20 of the shell 10 are arranged opposite to each other, and the top cover 20, the bottom wall 11 of the shell 10 and the multiple side walls 12 of the shell 10 are connected to form a sealed cavity 6.

[0069] In some embodiments, the insulating layer 40 is coated on the bottom wall 11 and the plurality of side walls 12. In some embodiments, the insulating layer 40 completely covers the outer surface of the housing 10, so that the insulating performance of the housing 10 is ensured without dead corners by the insulating layer 40.

[0070] In some embodiments, the housing 10 is an integrated structure, that is, the bottom wall 11 of the housing 10 and the plurality of side walls 12 of the housing 10 are integrally formed, such as integrally injection molded.

[0071] In some embodiments, the battery core 5 is roughly in a rectangular parallelepiped structure. Of course, in some other embodiments, the battery core 5 can also be roughly in a cube structure or a structure of other shapes.

[0072] In order to make the insulating layer 40 cover the shell 10 and the top cover 20 and maintain an integrated structure. In some embodiments, the insulating layer 40 and the shell 10 are an integrated structure, and the insulating layer 40 and the top cover 20 are an integrated structure. It can be understood that the insulating layer 40 and the shell 10 are an integrated structure, that is, the insulating layer 40 is directly formed on the outer surface of the shell 10, so that the insulating layer 40 can form an integrated structure with the shell 10. Similarly, the insulating layer 40 and the top cover 20 are an integrated structure, that is, the insulating layer 40 is directly formed on the outer surface of the top cover 20, so that the insulating layer 40 can form an integrated structure with the shell 10. In this embodiment, since the insulating layer 40 and the shell 10 are an integrated structure, and the insulating layer 40 and the top cover 20 are an integrated structure, the insulating layer 40 can be prevented from warping relative to the shell 10 and the top cover 20, and the insulating layer 40 can stably maintain the insulation performance of the shell 10 and the top cover 20, so that the shell 10 can be prevented from being negatively shorted and corroded. Furthermore, by directly forming the insulating layer 40 on the housing 10 and the top cover 20 , it is also convenient to form the insulating layer 40 in an integrated structure, thereby appropriately reducing the difficulty of providing the insulating layer 40 with an integrated structure.

[0073] In order to make the insulating layer 40 and the housing 10 form an integrated structure, and the insulating layer 40 and the top cover 20 form an integrated structure. In some embodiments, the insulating layer 40 is integrally injection molded on the outer surface of the housing 10 and the outer surface of the top cover 20 by injection molding. The insulating layer 40 can be formed on the outer surface of the housing 10 and the outer surface of the top cover 20 by integral injection molding, and the integral structure of the insulating layer 40 can be ensured, and the integrity of the insulating layer 40 can be ensured.

[0074] Of course, in some other embodiments, the material constituting the insulating layer 40 may be sprayed on the outer surface of the housing 10 and the outer surface of the top cover 20 to form the insulating layer 40. Forming the insulating layer 40 on the housing 10 and the top cover 20 by spraying can also ensure the integrated structure of the insulating layer 40 and the integrity of the insulating layer 40.

[0075] In some embodiments, the connection between the insulating layer 40 and the shell 10 is a sealed connection. It should be noted that the sealed connection between the insulating layer 40 and the shell 10 means that the insulating layer 40 has a sealing performance, and the insulating layer 40 and the shell 10 are an integrated structure, so that the positions where the shell 10 is provided with insulating sides can be isolated from the air outside the shell 10 by the insulating layer 40. In this embodiment, since the connection between the insulating layer 40 and the shell 10 is a sealed connection, the outer surface of the shell 10 is sealed and isolated from the air outside the shell 10, so that even if the position where the insulating layer 40 is wrapped on the top cover 20 is damaged due to special reasons, and the negative electrode column and the top cover 20 are overlapped by conductive debris, etc., it will not cause corrosion of the shell 10. The reasons why the shell 10 will not be corroded are as follows: when the top cover 20 is electrically connected to the negative electrode column, since the shell 10 is connected to the top cover 20, a potential difference is generated between the negative electrode column and the shell 10, so that the electron channel between the negative electrode column and the shell 10 is connected, and since the shell 10 is in direct contact with the electrolyte 31, the ion channel between the shell 10 and the electrolyte 31 is connected, so that the cations in the electrolyte 31 are embedded in the shell 10 to form an alloy, but since the connection between the insulating layer 40 and the shell 10 is a sealed connection, the insulating layer 40 has a sealing effect on the shell 10, so that the external air will not contact the shell 10, so that the shell 10 embedded with cations can be prevented from contacting the air outside the battery cell 5 and pulverizing, so that the shell 10 can be prevented from leaking, and the electrolyte 31 cannot pass through the shell 10 to reach the insulating layer 40 and corrode and destroy the insulating layer 40.

[0076] Similarly, when the negative electrode sheet 32 ​​inside the shell 10 is short-circuited with the shell 10, a potential difference is generated between the negative electrode sheet 32 ​​and the shell 10, so that the electron channel between the negative electrode sheet 32 ​​and the shell 10 is connected, and because the shell 10 is in direct contact with the electrolyte 31, the ion channel between the shell 10 and the electrolyte 31 is connected, so that the cations in the electrolyte 31 are embedded in the shell 10 to form an alloy. However, since the connection between the insulating layer 40 and the shell 10 is a sealed connection, the insulating layer 40 has a sealing effect on the shell 10, so that the external air will not contact the shell 10, thereby preventing the shell 10 embedded with cations from contacting the air outside the battery cell 5 and pulverizing, thereby preventing the shell 10 from leaking, and the electrolyte 31 cannot pass through the shell 10 to reach the insulating layer 40 and corrode and damage the insulating layer 40.

[0077] In this embodiment, since the connection between the insulating layer 40 and the shell 10 is a sealed connection, whether the negative electrode sheet 32 ​​inside the battery cell 5 is short-circuited with the shell 10, or the negative electrode column outside the battery cell 5 is short-circuited with the shell 10, the shell 10 can be effectively prevented from being corroded by the electrolyte 31, and leakage of the shell 10 can be effectively prevented.

[0078] In some embodiments, the connection between the insulating layer 40 and the top cover 20 is a sealed connection. In this embodiment, during the transportation of the battery pack 3, the electrolyte 31 of the battery cell 5 can come into contact with the top cover 20 due to shaking or uneven placement, and the insulating layer 40 on the shell 10 is damaged, and the damaged shell 10 is short-circuited with the negative pole or other charged shells 10 or negative poles of the battery cell 5, so as to prevent the top cover 20 of the battery cell 5 from leaking. Specifically, it is because the insulating layer 40 isolates the top cover 20 from the outside air, so that even if the top cover 20 is electronically and ionically conductive at the same time, it will not be powdered because the insulating layer 40 isolates the top cover 20 from the outside air, so that there will be no leakage at the top cover 20.

[0079] It is understandable that when the negative electrode sheet 32 ​​inside the battery cell 5 is short-circuited with the top cover 20 or the housing 10 , the insulating layer 40 isolates the top cover 20 from the outside air and thus no powdering occurs, thereby preventing leakage at the top cover 20 .

[0080] In some embodiments, the housing 10 is made of aluminum or aluminum alloy to ensure sufficient strength to accommodate the electrolyte 31 and the pole piece 32, and the aluminum material has high heat dissipation and corrosion resistance. It is understandable that in other embodiments, the housing 10 can also be made of other materials, such as stainless steel.

[0081] In some embodiments, the insulating layer 40 may be a layered structure formed by one or more combinations of materials such as polyethylene (PE), polyvinyl chloride (PVC), polypropylene (PP), polytetrafluoroethylene (PTFE), polycarbonate (PC), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyamide (PA), resin, polyurethane, polyvinylidene fluoride (PVDF), etc. It is understandable that the layered structure that can meet the insulation requirements and can seal the shell 10, and the connection position can prevent the shell 10 from contacting the air outside the battery cell 5 belongs to the insulating layer 40 in this application.

[0082] In some embodiments, the insulating layer includes a thermally conductive material and an insulating material.

[0083] For example, in some embodiments, the insulating layer 40 includes one of a polyethylene layer, a polyvinyl chloride layer, a polypropylene layer, a polytetrafluoroethylene layer, a polycarbonate layer, a polyethylene terephthalate layer, a polyphenylene sulfide layer, and a polyamide layer doped with a thermally conductive material. In this embodiment, since the insulating layer 40 is doped with a thermally conductive material, the thermal conductivity of the insulating layer 40 can be effectively improved to improve the heat dissipation performance of the battery cell 5, so that the insulation capacity and heat dissipation of the battery cell 5 can be effectively improved.

[0084] In some embodiments, the thermal conductivity of the insulating layer 40 doped with the thermally conductive material is greater than 0.5 W / (mk). Since the thermal conductivity of the insulating layer 40 is greater than 0.5 W / (mk), it is effectively ensured that the heat dissipation performance of the insulating layer 40 meets the use requirements.

[0085] For example, in some embodiments, the thermal conductivity of the insulating layer 40 doped with the thermally conductive material is 0.5-55 W / (mk).

[0086] In some embodiments, the thermally conductive material doped in the insulating layer 40 can be high thermal conductivity graphite, high thermal conductivity carbon fiber, metal oxides (zinc oxide, copper oxide, magnesium oxide, beryllium oxide and aluminum oxide, etc.), metal nitrides (aluminum nitride, silicon nitride and boron nitride, etc.), metal carbides (silicon carbide, etc.), phase change materials (phase change silicone grease, etc.), etc.

[0087] It is understandable that the battery cell 5 in this embodiment can be a ternary lithium battery cell 5 , a lithium iron phosphate battery cell 5 , or a sodium ion battery cell 5 , etc. Of course, other types of battery cells 5 are also possible.

[0088] Figure 5 Figure 3 A cross-sectional view of a battery cell 5 in an embodiment; Figure 6 for Figure 5 A local enlarged schematic diagram of point A in the middle.

[0089] Reference Figure 5 and Figure 6 In some embodiments, the thickness h of the insulating layer 40 is 20 μm-2 mm. Within this range, the insulating layer 40 has sufficient strength to effectively avoid being worn and causing the shell 10 to be exposed, and at the same time, within this range, effective insulation performance can be provided to the shell 10 and the top cover 20. To avoid the phenomenon of short circuit between the shell 10 and the top cover 20 and the negative pole. It is understandable that the thickness h of the insulating layer 40 can be 20 μm, 50 μm, 100 μm, 200 μm, 500 μm, 1 mm, 1.5 mm, 2 mm, etc.

[0090] The top cover 20 is provided with a pole 50, and the portion of the insulating layer 40 covering the top cover 20 is provided with an opening 41 (such as Figure 4 ), the pole 50 passes through the opening 41. The pole 50 is exposed through the opening 41 to facilitate connection with other battery cells 5 in series or in parallel.

[0091] Reference Figure 6In some embodiments, the top cover 20 is provided with a fixing hole 21 for mounting the pole 50, and the battery pack 3 further includes a sealing ring 52, which is arranged between the radial outer peripheral surface of the pole 50 and the inner peripheral surface of the fixing hole 21, and a portion of the sealing ring 52 protrudes from the top cover 20, and the inner wall of the opening 41 of the insulating layer 40 surrounds the outer peripheral surface 522 of the sealing ring 52. In this embodiment, since the insulating layer 40 surrounds the outer peripheral surface 522 of the sealing ring 52, the inner wall of the opening 41 of the insulating layer 40 is seamlessly connected to the outer peripheral surface 522 of the sealing ring 52, thereby preventing debris from connecting to the top cover 20 through the gap between the insulating layer 40 and the outer peripheral surface 522 of the sealing ring 52, so as to ensure that the insulating layer 40 insulates and protects the top cover 20 and the shell 10 in all directions without dead angles, so as to prevent the shell 10 or the top cover 20 of the battery cell 5 from being corroded and leaking.

[0092] In some embodiments, the pole protrudes from the sealing ring 52 and is exposed inside the housing 4 of the battery pack 3 to facilitate electrical connection with the pole 50 of other battery cells 5 .

[0093] In some implementations, the pole 50 is substantially cylindrical.

[0094] In some embodiments, the sealing ring 52 includes an inner circumferential surface 521 in contact with the radial outer circumferential surface of the pole 50 and an outer circumferential surface 522 opposite to the inner circumferential surface 521 of the sealing ring 52, and the outer circumferential surface 522 of the sealing ring 52 is connected to the inner wall of the fixing hole 21 of the top cover 20. Thus, the top cover 20 is separated from the pole 50 by the sealing ring 52.

[0095] In some embodiments, for example, when the pole 50 is a positive pole, the sealing ring 52 can be made of a conductive material to electrically connect the pole 50 and the top cover 20. At this time, the shell 10 is also charged. By electrically connecting the positive pole to the shell 10, the potential of the shell 10 can be increased to effectively avoid the potential of the shell 10 being lower than its lithium insertion potential, thereby improving the problem that the anode ions are easily embedded in the shell 10 to form an alloy.

[0096] Of course, in some embodiments, when the pole 50 is a positive pole, the sealing ring 52 of the positive pole can also be made of an insulating material, such as a plastic material. In this case, the sealing ring 52 of the positive pole insulates the pole 50 from the shell 10, and the shell 10 will no longer be charged.

[0097] In some embodiments, when the pole 50 is a negative pole, the sealing ring 52 is made of an insulating material. At this time, the pole 50 of the negative pole is insulated and separated from the shell 10 to avoid a short circuit between the negative pole and the shell 10 .

[0098] In some embodiments, the outer circumferential surface 522 of the sealing ring 52 of the positive electrode column and the outer circumferential surface 522 of the sealing ring 52 of the negative electrode column are both surrounded by the insulating layer 40 .

[0099] In some embodiments, the insulating layer 40 is further provided with an opening for exposing the explosion-proof valve 60. Since the explosion-proof valve 60 is provided with an opening, the normal opening of the explosion-proof valve 60 will not be affected when the battery cell 5 is in danger, so as to ensure the safety of the battery cell 5.

[0100] It is understandable that in some embodiments, the insulating layer 40 is provided with openings at positions corresponding to the QR code of the battery cell 5 and the shell pressure test points, so that the QR code of the battery cell 5 and the pressure test of the shell 10 can be used normally.

[0101] Figure 7 A schematic diagram of the structure of another battery cell 5 provided in an embodiment of the present application.

[0102] Reference Figure 7 In some embodiments, the battery core 5 further includes an outer layer 70 , which is coated on the outer surface of the insulating layer 40 .

[0103] The outer layer 70 has stronger wear resistance than the insulating layer 40, so that the outer layer 70 is coated on the outer surface of the insulating layer 40, and the insulating layer 40 can be protected from being worn and damaged by the outer layer 70, thereby ensuring that the insulating layer 40 can stably maintain insulation protection for the shell 10 to prevent the shell 10 from contacting with external conductive objects, such as preventing conductive debris from overlapping the negative electrode column and the shell 10.

[0104] In some embodiments, the outer layer 70 only covers a portion of the insulating layer 40 , but does not completely cover the insulating layer 40 .

[0105] The outer layer 70 includes a bottom wall 71 and a plurality of side walls 72 connected to the bottom wall 71, wherein the bottom wall 71 of the outer layer 70 corresponds to the bottom wall 11 of the housing 10, and the side walls 72 of the outer layer 70 correspond to the side walls 12 of the housing 10. The portion of the insulating layer 40 located at the bottom wall 11 of the housing 10 is completely covered by the bottom wall 71 of the outer layer 70, and the portion of the insulating layer 40 located at the side wall 12 of the housing 10 is at least partially covered by the outer layer 70.

[0106] For example, in some embodiments, the height of the side wall 72 of the outer layer 70 is higher than the height of the electrolyte 31 in the shell 10, and the insulating layer 40 is sealed and connected to the outer surface of the shell 10. In this embodiment, since the insulating layer 40 also has a sealing function, and the height of the side wall 72 of the outer layer 70 is higher than the height of the electrolyte 31, the insulating layer 40 corresponding to the portion of the shell 10 in contact with the electrolyte 31 can be effectively protected by the outer layer 70 to prevent the insulating layer 40 corresponding to the portion of the shell 10 in contact with the electrolyte 31 from being worn and worn. As long as the insulating layer 40 corresponding to the portion of the shell 10 in contact with the electrolyte 31 can be effectively protected by the outer layer 70, the portion of the shell 10 in contact with the electrolyte 31 can be sealed and isolated from the external air by the insulating layer 40, so that the portion of the shell 10 in contact with the electrolyte 31 will never be powdered, and there will be no leakage.

[0107] It is understandable that in some other embodiments, the outer layer 70 may also completely cover the entire insulating layer 40 .

[0108] In some embodiments, the outer layer 70 may be a metal layer, such as an aluminum layer or an aluminum alloy layer, to improve the overall strength of the housing 10. Of course, in some other embodiments, the outer layer 70 may also be a non-metal layer, as long as it has high strength, hardness and wear resistance and can effectively protect the insulating layer 40, and the outer layer 70 may be made of other materials within the scope of protection of the present application.

[0109] In some embodiments, when the outer layer 70 is a metal layer, since the insulating layer 40 is located between the housing 10 and the outer layer 70, the insulating layer 40 can also play a role in insulating and isolating the outer layer 70 and the housing 10. Therefore, the outer layer 70 is not charged, and the outer layer 70 does not contact the electrolyte 31. Therefore, when the outer layers 70 of adjacent battery cells 5 contact each other, there will be no short circuit between the adjacent battery cells 5, and the outer layer 70 will not be corroded.

[0110] In some embodiments, the thickness of the outer layer 70 is 0.2 mm-0.5 mm, such as 0.2 mm, 0.3 mm, 0.4 mm or 0.5 mm. When the outer layer 70 is within this range, it is sufficiently wear-resistant and can effectively protect the insulating layer 40 to prevent the insulating layer 40 from being worn. It can also prevent the outer layer 70 from being too thick, which affects the energy density of the battery cell 5.

[0111] In some embodiments, the outer layer 70 and the insulating layer 40 are an integral structure. For example, the outer layer 70 is formed on the outer surface of the insulating layer 40 by injection molding. Of course, in some other embodiments, the outer layer 70 can also be formed on the insulating layer 40 by other methods such as spraying. By setting the outer layer 70 and the insulating layer 40 as an integral structure, it is not only helpful to reduce the thickness of the outer layer 70, but also the outer layer 70 is not easy to warp.

[0112] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A battery pack, characterized in that: The battery pack comprises a shell and a plurality of battery cells contained in the shell, wherein the battery cells comprise a shell, a top cover sealed on the shell, and a pole piece and an electrolyte contained in a sealed cavity surrounded by the shell and the top cover; The battery core further includes an insulating layer coated on the outer surface of the shell and the outer surface of the top cover. The insulating layer coated on the outer surface of the shell and the outer surface of the top cover is an integrated structure and is exposed in the outer shell.

2. The battery pack according to claim 1, characterized in that: The insulating layer and the shell are an integrated structure, and the insulating layer and the top cover are an integrated structure.

3. The battery pack according to claim 1, characterized in that: The connection between the insulating layer and the shell and the top cover is a sealed connection.

4. The battery pack according to claim 2, characterized in that: The top cover is provided with a pole, the portion of the insulating layer covering the top cover is provided with an opening, and the pole passes through the opening.

5. The battery pack according to claim 4, characterized in that: The top cover is provided with a fixing hole for mounting the pole, and the battery pack also includes a sealing ring, which is arranged around the radial outer circumference of the pole and the inner circumference of the fixing hole, a portion of the sealing ring protrudes from the top cover, and the inner wall of the opening surrounds the outer circumference of the sealing ring.

6. The battery pack according to claim 4, characterized in that: The insulating layer is also provided with openings for exposing a QR code of the battery core, an explosion-proof valve, and a shell pressure test point.

7. The battery pack according to claim 1, characterized in that: The thickness of the insulating layer is 20 μm-2 mm.

8. The battery pack according to claim 1, characterized in that: The insulating layer includes a thermal conductive material and an insulating material.

9. The battery pack according to claim 8, characterized in that: The thermal conductivity of the insulating layer is greater than 0.5 W / (mk).

10. An energy storage device, characterized in that: It comprises a cabinet and a plurality of battery packs as described in any one of claims 1 to 9, wherein the plurality of battery packs are arranged in the cabinet.

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