Battery monomer, battery and electric device

Abstract

The utility model relates to a battery monomer, a battery and a power utilization device, and the battery monomer comprises a shell with one end provided with an opening; the top cover is arranged on the opening in a covering mode, and an accommodating cavity is defined by the top cover and the shell; the electrode assembly is arranged in the accommodating cavity; wherein a first insulation structure is arranged between the inner surface of the shell and the electrode assembly, and a second insulation structure is arranged on the outer surface of the shell; at least one of the first insulating structure and the second insulating structure is an insulating coating. According to the battery monomer, the insulating coating is used for replacing a blue film covering the shell and / or an insulating film covering the electrode assembly and a bottom supporting plate arranged between the bottom of the electrode assembly and the shell, so that the volume proportion of the insulating coating in the overall structure of the battery monomer is smaller, and the overall energy density of the battery monomer can be effectively improved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery cell, a battery, and an electrical device. Background Art

[0002] The shell of a battery cell is usually a metal shell. In order to avoid potential difference or electrochemical corrosion between the electrode assembly inside the shell and the shell, the electrode assembly and the shell need to be insulated. At the same time, in order to avoid leakage current inside the battery cell and short circuit caused by conduction between the shell and the external structure, the outside of the shell also needs to be insulated.

[0003] However, the currently used insulation structure occupies a large space in the overall structure of the battery cell, which to some extent affects the volume ratio of the electrode assembly in the overall structure of the battery cell, thereby affecting the overall energy density of the battery cell. Utility Model Content

[0004] Based on this, it is necessary to provide a battery cell, a battery and an electrical device to address the problem that the current insulation structure occupies a large space in the overall structure of the battery cell, affecting the overall energy density of the battery cell.

[0005] In the first aspect, the present application provides a battery cell, comprising a shell, a top cover and an electrode assembly, wherein an opening is provided at one end of the shell; the top cover is covered on the opening and together with the shell forms a accommodating cavity; the electrode assembly is arranged in the accommodating cavity; wherein a first insulating structure is provided between the inner surface of the shell and the electrode assembly, and a second insulating structure is provided on the outer surface of the shell, and at least one of the first insulating structure and the second insulating structure is an insulating coating.

[0006] Through the above structure, an insulating coating is used to replace the blue film covering the outside of the shell and / or the insulating film (i.e., mylar film) covering the outside of the electrode assembly and the bottom support plate arranged between the bottom of the electrode assembly and the shell. In this way, the volume of the insulating coating in the overall structure of the battery cell is smaller, which can effectively improve the overall energy density of the battery cell.

[0007] In some embodiments, when the first insulating structure is an insulating coating, it is coated on the inner surface of the shell; when the second insulating structure is an insulating coating, it is coated on the outer surface of the shell.

[0008] Through the above structure, the insulating coating is directly coated on the inner surface or outer surface of the shell, which can effectively reduce the volume proportion of the insulating coating in the overall structure of the battery cell and improve the energy density of the battery cell.

[0009] In some embodiments, the shell includes a bottom plate and side plates arranged around the outer periphery of the bottom plate, the bottom plate is arranged opposite to the opening, one end of the side plate is connected to the bottom plate, and the other end is constructed as a welding surface, which is used for welding to the top cover; wherein, the inner surface and / or outer surface of the bottom plate is coated with an insulating coating, the inner surface and / or outer surface of the side plate is coated with an insulating coating, and the welding surface is not provided with an insulating coating.

[0010] Thus, the welding surface can be welded to the top cover more stably, so that the top cover can be stably sealed at the opening.

[0011] In some embodiments, when the inner surface of the side plate is coated with an insulating coating, the inner surface of the side plate includes a coated area and an uncoated area, the uncoated area is connected to the welding surface, and the insulating coating is provided in the coated area.

[0012] When the top cover is welded to the shell, the top cover overlaps the welding surface and the uncoated area at the same time and is connected by welding. Therefore, the provision of the uncoated area can make the connection between the side plate and the top cover more stable and improve the sealing performance of the top cover at the opening.

[0013] In some embodiments, the battery cell further includes an insulating member disposed between the top cover and the electrode assembly; wherein, in the height direction of the shell, the height of the uncoated area is H1, the thickness of the top cover is d, the height of the insulating member is H2, and d≤H1≤d+H2.

[0014] Through the above structure, the top cover can be more stably welded to the shell through the uncoated area. At the same time, the electrode assembly can be more safely arranged in the accommodating cavity, reducing the probability of short circuit caused by contact between the electrode assembly and the uncoated area.

[0015] In some embodiments, the material of the insulating coating includes at least one of acrylic insulating paint, silicone rubber insulating paint, polyurethane insulating paint, nitrocellulose lacquer insulating paint, fine enamel insulating paint, fluorocarbon insulating paint, and epoxy resin insulating paint.

[0016] Therefore, the insulating coating adopts the above materials to achieve the insulation, corrosion resistance and high strength properties of the insulating coating, so that the insulating coating can better play an insulating role and better protect the structure of the shell and the electrode assembly.

[0017] In some embodiments, the thickness of the insulating coating ranges from 0 μm to 100 μm.

[0018] Based on this, the present application can replace the blue film by applying an insulating coating, and the thickness range of the insulating coating is set at 0μm~100μm, which can further reduce the volume proportion of the insulating coating in the battery cell and improve the energy density of the battery cell.

[0019] In some embodiments, the thickness of the insulating coating ranges from 30 μm to 60 μm.

[0020] In a second aspect, the present application also provides a battery comprising the battery cell described above.

[0021] In a third aspect, the present application also provides an electrical device comprising the battery as described above.

[0022] The above-mentioned battery cells, batteries and electrical devices use an insulating coating to replace the blue film covering the outside of the shell and / or the insulating film covering the outside of the electrode assembly and the bottom support plate arranged between the bottom of the electrode assembly and the shell. In this way, the volume of the insulating coating in the overall structure of the battery cell accounts for a smaller proportion, which can effectively improve the overall energy density of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic diagram of the overall structure of a battery cell according to one or more embodiments.

[0024] Figure 2 Schematic diagram of the structure of a shell in a battery cell according to one or more embodiments.

[0025] Figure 3 is a cross-sectional view of a case in a battery cell according to one or more embodiments.

[0026] Figure 4 for Figure 2 A partial enlarged view of point A in the middle.

[0027] Figure 5 Schematic diagram of the structure of a top cover in a battery cell according to one or more embodiments.

[0028] Explanation of the accompanying drawings: 100, battery cell; 10, shell; 20, top cover; 30, electrode assembly; 40, insulating part; 11, opening; 12, insulating coating; 13, inner surface; 14, outer surface; 15, bottom plate; 16, side plate; 17, welding surface; 18, coated area; 19, uncoated area. DETAILED DESCRIPTION

[0029] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0030] In the description of this application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0031] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of this application, if the term "plurality" appears, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0032] In this application, unless otherwise specified or limited, the terms "mounted," "connected," "connected," "fixed," etc., should be interpreted broadly. For example, these terms may refer to fixed connections, removable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediary; and internal communication between two components or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0033] In this application, unless otherwise expressly specified or limited, if a first feature is described as being "above" or "below" a second feature, or similar descriptions, this may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is described as being "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is described as being "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0034] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only embodiment.

[0035] Currently, market developments indicate that power batteries are becoming increasingly widely used. They are not only used in energy storage systems such as hydropower, thermal, wind, and solar power plants, but are also widely used in electric vehicles like electric bicycles, electric motorcycles, and electric vehicles, as well as in military equipment and aerospace. As power battery applications continue to expand, market demand is also growing.

[0036] A battery cell is the smallest unit of a battery. It typically consists of a housing, a top cover, and an electrode assembly. The housing is typically metal, with an opening at one end. The electrode assembly is placed into the housing through the opening, and the top cover is then sealed against the opening. This allows the electrode assembly to be placed within the cavity formed by the top cover and the housing. The top cover and the housing provide some protection for the electrode assembly.

[0037] The electrode assembly is the component in the battery cell where the electrochemical reaction actually occurs. During the use of the battery cell, short circuits or electrochemical corrosion may occur between the electrode assembly and the shell, or between the shell and the external environment. For example, when the electrode assembly is placed in the shell, if the electrode assembly contacts the shell, a potential difference will be generated, which is prone to electrochemical corrosion. Furthermore, when leakage current occurs in the structure inside the shell, conduction is formed between the shell, and then connected to other external battery cells or other components, it will cause a more serious short circuit problem in the battery cell. In addition, the outside of the shell may also be subject to chemical and physical erosion risks such as external water vapor corrosion and particle scratches.

[0038] To address this issue, an insulating structure is required, either between the electrode assembly and the housing, or on the exterior of the housing. Currently, a common practice is to coat the periphery of the electrode assembly with insulating material, specifically Mylar film (a polyester polymer film). This Mylar film provides insulation between the electrode assembly and the inner wall of the housing, effectively insulating the two. Furthermore, a bottom support plate is placed between the bottom of the electrode assembly and the bottom wall of the housing, separating the bottom of the electrode assembly from the bottom wall of the housing.

[0039] The thickness of a single layer of Mylar film is 100μm. At least one Mylar film layer is required during wrapping, and the thickness of the Mylar film at the overlapping end reaches over 200μm. Meanwhile, the thickness of the base plate is typically 300μm. Therefore, the Mylar film and base plate occupy a large space inside the housing, affecting the volume ratio of the electrode assembly within the housing.

[0040] In addition, a blue film is typically applied to the exterior of the battery housing. This film is typically a polymer film, such as polypropylene (PP) or polyethylene (PE). Due to process requirements, the blue film typically has a thickness of 110μm or greater. Furthermore, where the blue film overlaps, its thickness is at least the sum of the thicknesses of two layers. This significantly increases the volumetric proportion of the blue film within the overall battery cell structure.

[0041] Based on this, the currently used insulation structure occupies a large space in the overall structure of the battery cell, which to a certain extent affects the volume ratio of the electrode assembly in the overall structure of the battery cell, thereby affecting the overall energy density of the battery cell.

[0042] Based on the above considerations, in order to solve the problem that the current insulating structure occupies a large space in the overall structure of the battery cell, affecting the overall energy density of the battery cell, a battery cell is provided in one or more embodiments of the present application, which replaces the blue film covering the outside of the shell and / or the insulating film covering the outside of the electrode assembly and the bottom support plate arranged between the bottom of the electrode assembly and the shell with an insulating coating. In this way, the volume of the insulating coating in the overall structure of the battery cell accounts for a smaller proportion, which can effectively improve the overall energy density of the battery cell.

[0043] It should be noted that the battery apparatus mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells, which are connected in series, parallel, or in a hybrid manner via a busbar.

[0044] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells. For example, a battery cell assembly can be a battery module, which is a single module formed by arranging and securing multiple battery cells. For example, a battery module can be formed by bundling multiple battery cells using cable ties.

[0045] In some embodiments, the battery may be a battery pack, which includes a case and one or more battery cell assemblies, wherein the battery cell assemblies are housed in the case.

[0046] As an example, the battery cell assembly may be a battery module, and the battery cell assembly may be accommodated in the box by fixing the battery module in the box.

[0047] As an example, the battery cell assembly may also be housed in the box by directly fixing the plurality of battery cells to the box.

[0048] Please also refer to Figure 1 、 Figure 2 as well as Figure 3 One embodiment of the present application provides a battery cell 100 comprising a housing 10, a top cover 20, and an electrode assembly 30. The housing 10 has an opening 11 at one end. The top cover 20 covers the opening 11 and, together with the housing 10, forms a housing cavity. The electrode assembly 30 is disposed in the housing cavity. A first insulating structure is disposed between the inner surface of the housing 10 and the electrode assembly 30. A second insulating structure is disposed on the outer surface of the housing 10. At least one of the first insulating structure and the second insulating structure is an insulating coating 12.

[0049] It should be noted that the shell 10 refers to a structure that can provide accommodation space for the electrode assembly 30 and play a protective role. The shell 10 is usually set as a metal shell, and an opening 11 is set at one end to facilitate the placement of the electrode assembly 30 into the shell 10 through the opening 11.

[0050] The top cover 20 is a structure that seals the opening 11 of the housing 10 and, together with the housing 10, forms a housing cavity. The electrode assembly 30 is located within the housing cavity, and the electrolyte is filled into the housing cavity to allow the electrolyte to fully penetrate the electrode assembly 30, allowing the electrode assembly 30 to smoothly undergo an electrochemical reaction.

[0051] The shell 10 includes an inner surface 13 and an outer surface 14. Since the shell 10 is a metal shell, in order to avoid problems such as short circuit between the electrode assembly 30 placed inside the shell 10 and the shell 10, it is usually necessary to set a first insulating structure between the inner surface 13 of the shell 10 and the electrode assembly 30.

[0052] If leakage occurs within the housing 10, the housing 10 may also communicate with other external battery cells or components, potentially causing a short circuit. Furthermore, the exterior of the housing 10 is subject to chemical and physical corrosion, such as corrosion from external moisture and scratches from particles. Therefore, a second insulating structure is required on the outer surface 14 of the housing 10.

[0053] When the first insulating structure is the insulating coating 12, the insulating coating 12 acts as an insulator between the electrode assembly 30 and the inner wall of the accommodating cavity. In this way, the current Mylar film and bottom guard plate can be replaced, so that the electrode assembly 30 can be directly placed in the housing 10.

[0054] Furthermore, when the second insulating structure is an insulating coating 12, the insulating coating 12 provides protection and insulation for the outer periphery of the housing 10, thereby replacing the existing blue film. Furthermore, the thickness of the insulating coating 12 is more uniform than that of the blue film, effectively reducing the thickness ratio around the outer periphery of the housing 10.

[0055] In addition, the insulating coating 12 can be applied by dipping, spraying, and brushing. For larger housings 10, dipping can be used to apply the insulating coating 12 to the surface of the housing 10. For medium-sized housings 10, spraying can be used to apply the insulating coating 12 to the surface of the housing 10. For smaller housings 10, brushing can be used to apply the insulating coating 12 to the surface of the housing 10.

[0056] After the insulating coating 12 is coated by the above coating method, the insulating coating 12 is cured by UV curing, thermal curing, moisture curing, electrical curing, air curing, light-dark mixed polymerization reaction, etc., so that it can be more stably attached to the surface of the shell 10.

[0057] Through the above structure, the insulating coating 12 is used to replace the blue film covering the outside of the shell 10 and / or the insulating film (i.e., mylar film) covering the outside of the electrode assembly 30 and the bottom support plate arranged between the bottom of the electrode assembly 30 and the shell 10. In this way, the volume of the insulating coating 12 in the overall structure of the battery cell 100 accounts for a smaller proportion, which can effectively improve the overall energy density of the battery cell 100.

[0058] In some embodiments, when the first insulating structure is the insulating coating 12 , it is coated on the inner surface 13 of the housing 10 . When the second insulating structure is the insulating coating 12 , it is coated on the outer surface 13 of the housing 10 .

[0059] Specifically, the inner surface 13 of the housing 10 is arranged toward the interior of the accommodating cavity, that is, the inner surface 13 of the housing 10 forms an inner wall of the accommodating cavity, and the outer surface 14 of the housing 10 is arranged away from the accommodating cavity.

[0060] The insulating coating 12 may be coated on at least one of the inner surface 13 and the outer surface 14 of the housing 10 , that is, at least three embodiments are included.

[0061] In the first embodiment, the insulating coating 12 is applied only to the inner surface 13 of the housing 10. In this case, the insulating coating 12 can replace the currently used Mylar film and base plate structure, reducing the volume of the insulating coating 12 within the housing 10, providing more space for the electrode assembly 30, and thus effectively increasing the energy density of the battery cell 100.

[0062] In the second embodiment, the insulating coating 12 is applied only to the outer surface 14 of the housing 10. This insulating coating 12 on the outer surface 14 of the housing 10 can replace the existing blue film. Since the insulating coating 12 has no overlapping sections, its overall thickness is more uniform. Furthermore, the thickness of the insulating coating 12 is less than that of the blue film, thereby reducing the volume of the insulating coating 12 within the overall structure of the battery cell 100 and increasing the energy density of the battery cell 100.

[0063] In a third embodiment, the insulating coating 12 is applied to both the inner surface 13 and the outer surface 14 of the housing 10. This embodiment minimizes the volume occupied by the insulating coating 12 within the overall structure of the battery cell 100, further increasing the energy density of the battery cell 100. Furthermore, the material and manufacturing costs of the insulating coating 12 are lower.

[0064] Through the above structure, the volume proportion of the insulating coating 12 in the overall structure of the battery cell 100 can be effectively reduced, thereby improving the energy density of the battery cell 100 .

[0065] like Figure 2 、 Figure 3 as well as Figure 4 As shown, in some embodiments, the housing 10 includes a bottom plate 15 and a side plate 16 disposed around the periphery of the bottom plate 15. The bottom plate 15 is disposed opposite the opening 11. One end of the side plate 16 is connected to the bottom plate 15, and the other end is configured as a welding surface 17. The welding surface 17 is used for welding to the top cover 20. The inner surface 13 and / or the outer surface 14 of the bottom plate 15 is coated with an insulating coating 12. The inner surface 13 and / or the outer surface 14 of the side plate 16 is also coated with an insulating coating 12, and the welding surface 17 is not coated with the insulating coating 12.

[0066] Specifically, the bottom plate 15 of the shell 10 is set to a rectangular structure, and four side panels 16 can be set, and the four side panels 16 are respectively connected to the four sides of the bottom plate 15, so that the bottom plate 15 and the side panels 16 together enclose a cavity structure with an opening 11 at one end, and the bottom plate 15 is arranged opposite to the opening 11.

[0067] The side surface of side panel 16 facing the accommodating cavity is inner surface 13, and the side surface facing away from the accommodating cavity is outer surface 14. Side panel 16 also defines an end surface between inner surface 13 and outer surface 14. One end surface is connected to bottom panel 15, while the other end surface faces away from bottom panel 15. The end surface facing away from bottom panel 15 is a welding surface 17. When top cover 20 is sealed against opening 11, top cover 20 and welding surface 17 are sealedly connected by welding, thereby achieving a sealed arrangement of top cover 20 against opening 11.

[0068] Furthermore, a side surface of the bottom plate 15 facing the accommodating cavity is also configured as an inner surface 13 , and a side surface facing away from the accommodating cavity is configured as an outer surface 14 .

[0069] When the inner surface 13 of the housing 10 is coated with the insulating coating 12, the inner surface 13 of the bottom plate 15 and the inner surface 13 of the side plate 16 are also coated with the insulating coating 12. When the outer surface 14 of the housing 10 is coated with the insulating coating 12, the outer surface 14 of the bottom plate 15 and the outer surface 14 of the side plate 16 are also coated with the insulating coating 12.

[0070] Meanwhile, the welding surface 17 is not provided with the insulating coating 12. The insulating coating 12 can be applied to other surfaces of the side panel 16, avoiding the welding surface 17. Alternatively, the insulating coating 12 on the welding surface 17 can be polished after the entire coating is applied, exposing the metal body of the welding surface 17. This allows for a more stable weld between the welding surface 17 and the top cover 20, ensuring a stable seal of the top cover 20 against the opening 11.

[0071] In some embodiments, when the inner surface 13 of the side panel 16 is coated with the insulating coating 12 , the inner surface 13 of the side panel 16 includes a coated area 18 and an uncoated area 19 , the uncoated area 19 is connected to the welding surface 17 , and the insulating coating 12 is disposed in the coated area 18 .

[0072] Specifically, the inner surface 13 of the side plate 16 includes a coated area 18 and an uncoated area 19, wherein the uncoated area 19 is located near the welding surface 17 and is connected to the welding surface 17. When the inner surface 13 of the side plate 16 is coated with the insulating coating 12, the insulating coating 12 is only applied to the coated area 18, that is, the uncoated area 19 does not have the insulating coating 12.

[0073] When the top cover 20 is welded to the housing 10, the top cover 20 overlaps with both the welding surface 17 and the uncoated area 19, and the connection is achieved by welding. Therefore, the provision of the uncoated area 19 can make the connection between the side plate 16 and the top cover 20 more stable, and improve the sealing performance of the top cover 20 at the opening 11.

[0074] like Figure 1 、 Figure 3 as well as Figure 5 As shown, in some embodiments, the battery cell 100 further includes an insulating member 40, which is disposed between the top cover 20 and the electrode assembly 30. In the height direction of the housing 10, the height of the uncoated area 19 is H1, the thickness of the top cover 20 is d, and the height of the insulating member 40 is H2, where d≤H1≤d+H2.

[0075] Specifically, the insulating member 40 is a structure disposed between the top cover 20 and the electrode assembly 30 to insulate the top cover 20 and the electrode assembly 30. The insulating member 40 can be configured as a lower plastic, which is fixed to the side of the top cover 20 facing the interior of the accommodating cavity. When the top cover 20 is sealed to the opening 11, the lower plastic is located between the top cover 20 and the electrode assembly 30, providing insulation.

[0076] The height direction of the housing 10 refers to the direction perpendicular to the top cover 20 when the top cover 20 is sealed over the opening 11. The height of the uncoated area 19 is H1, the thickness of the top cover 20 is d, and the height of the insulating member 40 is H2, where d ≤ H1 ≤ d + H2. Therefore, the minimum height of the uncoated area 19 is equal to the thickness of the top cover 20. This ensures that when the top cover 20 is welded to the housing 10, it will precisely contact the uncoated area 19, thereby improving the welding stability of the top cover 20.

[0077] Furthermore, the maximum height of the uncoated area 19 is the sum of the thickness of the top cover 20 and the height of the lower plastic. The height of the lower plastic is equal to the thickness of the lower plastic. Therefore, the maximum height of the uncoated area 19 is the sum of the thicknesses of the top cover 20 and the lower plastic. This prevents the electrode assembly 30 from overlapping the uncoated area 19 due to the restraining effect of the lower plastic, thereby reducing the possibility of short circuits in the electrode assembly 30.

[0078] Through the above structure, the top cover 20 can be more stably welded to the shell 10 through the uncoated area 19. At the same time, the electrode assembly 30 can be more safely arranged in the accommodating cavity, reducing the probability of the electrode assembly 30 contacting the uncoated area 19 and causing a short circuit.

[0079] In some embodiments, the material of the insulating coating 12 includes at least one of acrylic insulating paint, silicone rubber insulating paint, polyurethane insulating paint, nitrocellulose lacquer insulating paint, fine enamel insulating paint, fluorocarbon insulating paint, and epoxy resin insulating paint.

[0080] Specifically, acrylic insulating varnish is composed of acrylic ester monomers and additives, and has excellent electrical insulation properties and mechanical strength. Silicone rubber insulating varnish is a mixture of silicone rubber resin and solvent, and has excellent high-temperature resistance and electrochemical corrosion resistance. Polyurethane insulating varnish is composed of polyurethane resin and solvent, and has excellent electric shock resistance and chemical resistance. Nitrocellulose lacquer insulating varnish is a mixture of nitrocellulose resin and solvent, and has excellent insulation properties and heat resistance. Fine enamel insulating varnish is a mixture of fine porcelain particles and organic matter, and has high insulation strength and low dielectric loss. Fluorocarbon insulating varnish is a mixture of fluorocarbon resin and solvent, and has excellent chemical resistance and heat resistance.

[0081] In actual application, corresponding materials can be selected according to specific requirements of the insulating coating 12 in different battery cells 100, which will not be described in detail here.

[0082] Therefore, the insulating coating 12 adopts the above-mentioned materials to achieve the insulation, corrosion resistance and high strength properties of the insulating coating 12, so that the insulating coating 12 can better play an insulating role and better protect the structure of the shell 10 and the electrode assembly 30.

[0083] In some embodiments, the thickness of the insulating coating 12 ranges from 0 μm to 100 μm.

[0084] It should be noted that the blue film is currently coated on the outside of the shell 10. In order to ensure that the blue film has more stable insulation performance and taking into account the operability during the processing, the thickness of the blue film is relatively fixed, usually 100μm. In addition, during the coating process, the blue film is usually coated with multiple layers in order to be more complete, which further increases the volume share of the blue film in the overall structure of the battery cell 100. However, even if only one layer of blue film is coated, the head and tail positions need to overlap to achieve a closed loop of blue film coating, which leads to an increase in the thickness of the overlapping positions of the head and tail, which not only takes up more volume, but also makes the overall thickness of the blue film uneven.

[0085] Based on this, the present application can replace the blue film by coating the insulating coating 12, and the thickness range of the insulating coating 12 is set at 0μm~100μm, which can further reduce the volume proportion of the insulating coating 12 in the battery cell 100 and improve the energy density of the battery cell 100.

[0086] In some embodiments, the thickness of the insulating coating 12 ranges from 30 μm to 60 μm.

[0087] It should be noted that the thickness range of the insulating coating 12 needs to take into account the workability of the metal shell it covers and the proportion of the thickness of the insulating coating 12 in the overall volume of the battery cell 100 .

[0088] Based on this, setting the thickness of the insulating coating 12 within the above range can not only better meet the processability of the shell 10, but also further reduce the volume proportion of the insulating coating 12 in the battery cell 100 and improve the energy density of the battery cell 100.

[0089] In some embodiments, both the inner surface 13 and the outer surface 14 of the housing 10 are coated with an insulating coating 12 .

[0090] Specifically, the insulating coating 12 coated on the inner surface 13 of the housing 10 can replace the Mylar film covering the periphery of the electrode assembly 30 and the base plate disposed between the bottom of the electrode assembly 30 and the housing 10, while the insulating coating 12 coated on the outer surface 14 of the housing 10 can replace the blue film covering the exterior of the housing 10. This can further reduce the volume of the insulating coating 12 in the overall structure of the battery cell 100, further improving the energy density of the battery cell 100.

[0091] Based on the same concept as the above-mentioned battery cell 100 , the present application provides a battery including the above-mentioned battery cell 100 .

[0092] Based on the same concept as the above-mentioned battery, the present application also provides an electrical device, including the above-mentioned battery.

[0093] According to one or more embodiments, taking the dimensions of a standard square aluminum-cased battery cell 100 as an example, the housing 10 has a width of 147.78 mm, a height of 97.34 mm, and a thickness of 28.78 mm. The positive electrode of the electrode assembly 30 can use a high-nickel ternary positive electrode material, while the negative electrode uses conventional graphite. The separator is a polyethylene (PE) separator, and the interior of the housing 10 is filled with conventional lithium hexafluorophosphate (LiPF6) electrolyte. The capacity of the battery cell 100 is 70 Ah.

[0094] In a comparative example, the exterior of the housing 10 is coated with a blue film having a thickness of 110 μm. After coating, the width of the housing 10 is 148 mm. Due to folds in the blue film at the corners of the housing 10, the blue film has at least six layers along the height of the housing 10. Consequently, the height of the housing 10 after coating is 98 mm, and the thickness of the housing 10 after coating is 29 mm.

[0095] In one embodiment, polyurethane (PU) insulating varnish is applied to the outer surface 14 of the housing 10 by dipping and then dried. By controlling the temperature, dipping time, extraction speed, and stagnation time, an insulating coating 12 with a thickness of 100 μm or 30 μm can be obtained.

[0096] The insulating coating 12 on the weld surface 17 and the uncoated area 19 is polished to expose the metal body of the aluminum shell. Then, the electrode assembly 30 is assembled into the interior of the shell 10, and the top cover 20 is sealed over the opening 11 to form the battery cell 100.

[0097] The results of the above comparative examples and embodiments are compared in the following table:

[0098]

[0099] It can be seen that the present application can effectively reduce the volume proportion of the insulating coating 12 in the overall structure of the battery cell 100 by coating the insulating coating 12 on the surface of the shell 10, thereby further improving the energy density of the battery cell 100.

[0100] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0101] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A battery cell, characterized in that: include: a shell having an opening at one end; A top cover, which covers the opening and forms a receiving cavity together with the shell; and an electrode assembly, disposed in the accommodating cavity; Wherein, a first insulating structure is provided between the inner surface of the shell and the electrode assembly, and a second insulating structure is provided on the outer surface of the shell; At least one of the first insulating structure and the second insulating structure is an insulating coating.

2. The battery cell according to claim 1, wherein: When the first insulating structure is the insulating coating, it is coated on the inner surface of the shell; When the second insulating structure is the insulating coating, it is coated on the outer surface of the shell.

3. The battery cell according to claim 2, characterized in that: The shell includes a bottom plate and a side plate arranged around the outer periphery of the bottom plate, the bottom plate is arranged opposite to the opening, one end of the side plate is connected to the bottom plate, and the other end is configured as a welding surface, and the welding surface is used for welding to the top cover; The inner surface and / or outer surface of the bottom plate is coated with the insulating coating, the inner surface and / or outer surface of the side plate is coated with the insulating coating, and the welding surface is not provided with the insulating coating.

4. The battery cell according to claim 3, characterized in that When the inner surface of the side plate is coated with the insulating coating, the inner surface of the side plate includes a coated area and an uncoated area, the uncoated area is connected to the welding surface, and the insulating coating is provided in the coated area.

5. The battery cell according to claim 4, characterized in that The battery cell further includes an insulating member disposed between the top cover and the electrode assembly; Wherein, in the height direction of the shell, the height of the uncoated area is H1, the thickness of the top cover is d, the height of the insulating member is H2, and d≤H1≤d+H2.

6. The battery cell according to any one of claims 1 to 5, characterized in that: The material of the insulating coating includes at least one of acrylic insulating paint, silicone rubber insulating paint, polyurethane insulating paint, nitrocellulose lacquer insulating paint, fine enamel insulating paint, fluorocarbon insulating paint, and epoxy resin insulating paint.

7. The battery cell according to any one of claims 1 to 5, characterized in that: The thickness of the insulating coating ranges from 0 μm to 100 μm.

8. The battery cell according to claim 7, characterized in that The thickness of the insulating coating ranges from 30 μm to 60 μm.

9. A battery, characterized in that: The battery cell comprises the battery cell according to any one of claims 1 to 8.

10. An electrical device, characterized in that: Comprising the battery of claim 9.

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