Separation film of electrode assembly, method and device for preparing separation film of electrode assembly

Abstract

The embodiments of the present application disclose an isolation membrane for an electrode assembly, a method and an apparatus for preparing the isolation membrane for an electrode assembly. The first surface of the isolation membrane includes a first circulation area and a first barrier area. The first barrier area is formed by spraying or scraping an insulating material on the edge areas on both sides along a first direction on the first surface. The first direction is perpendicular to the extension direction of the isolation membrane. The first circulation area is the area on the first surface except the first barrier area. The first circulation area is used to pass ions in the electrolyte, and the first barrier area is used to block ions in the electrolyte. The isolation membrane for an electrode assembly, the method and the apparatus for preparing the isolation membrane for an electrode assembly according to the embodiments of the present application can improve the performance of the isolation membrane, thereby improving the performance of the electrode assembly in the battery cell.

Description

Technical Field

[0001] The present application relates to the field of batteries, and more specifically, to an isolation membrane of an electrode assembly, and a method and device for preparing the isolation membrane of an electrode assembly. Background Art

[0002] Battery cells are one of the core components of various types of electrical equipment, and people have increasingly higher requirements for the various performances of battery cells, especially safety performance. Battery cells include internal electrode assemblies and electrolytes, wherein the electrode assemblies include anode pole pieces, cathode pole pieces, and separators. The separator is a porous and electronically insulating material. The main function of the separator is electronic insulation, while conducting ions in the electrolyte to prevent the cathode pole piece and the anode pole piece from overlapping and short-circuiting. The anode pole piece is usually set to cover the cathode pole piece, and the excess part is to prevent lithium deposition on the anode pole piece, and to prevent the burrs generated when the pole ear is formed by die-cutting from piercing the separator.

[0003] However, during the production process, it is very likely that the anode electrode cannot cover the cathode electrode, or the anode electrode wraps the cathode electrode in a poor size. In order to prevent this phenomenon from occurring during the manufacturing process, X-ray online detection is usually required. This detection is time-consuming, inefficient, increases manufacturing costs, and has low detection accuracy. Therefore, a solution is urgently needed to solve the current problem. Summary of the invention

[0004] The embodiments of the present application provide a separator of an electrode assembly, and a method and device for preparing the separator of an electrode assembly, which can improve the performance of the separator, and further improve the performance of the electrode assembly in a battery cell.

[0005] In a first aspect, an isolation membrane of an electrode assembly is provided, wherein a first surface of the isolation membrane comprises a first flow area and a first barrier area, wherein the first barrier area is formed by spraying or scraping an insulating material on both side edge areas along a first direction on the first surface, wherein the first direction is perpendicular to an extension direction of the isolation membrane, and the first flow area is an area on the first surface excluding the first barrier area, wherein the first flow area is used to pass ions in an electrolyte, and the first barrier area is used to block ions in the electrolyte.

[0006] Therefore, the isolation membrane of the embodiment of the present application is capable of blocking ions in the electrolyte due to the first barrier region provided in the edge region. Therefore, when the isolation membrane is used to wind and form an electrode assembly, the length of the anode electrode sheet and the cathode electrode sheet along the first direction is no longer limited, and the lithium deposition problem of the anode electrode sheet can be avoided by the first barrier region. Regardless of whether the length of the anode electrode sheet along the first direction is greater than, less than, or equal to the length of the cathode electrode sheet along the first direction, the lithium deposition problem of the anode electrode sheet can be avoided by the first barrier region, thereby reducing the processing difficulty and cost of the electrode assembly and improving the processing efficiency of the electrode assembly. In addition, the insulating material sprayed or scraped on the first barrier region can increase the strength of the region, effectively preventing the burrs left after the electrode sheet is die-cut to form the pole ear from piercing the first barrier region of the isolation membrane, and reducing the risk of short circuit caused by the burrs piercing the isolation membrane.

[0007] In some embodiments, the dimension of the first flow zone along the first direction is less than or equal to a first dimension, the first dimension is the dimension of the anode electrode piece isolated by the isolation membrane along the first direction, the dimension of the isolation membrane along the first direction is greater than the first dimension and greater than a second dimension, and the second dimension is the dimension of the cathode electrode piece isolated by the isolation membrane along the first direction.

[0008] The dimension of the first isolation membrane along the first direction is larger than the first dimension and larger than the second dimension. Thus, in the electrode assembly, both ends of the anode electrode sheet along the first direction and both ends of the cathode electrode sheet along the first direction can be made not to exceed both ends of the isolation membrane along the first direction, so as to ensure that the isolation membrane can block the anode electrode sheet and the cathode electrode sheet to avoid short circuit.

[0009] The dimension of the first flow zone along the first direction of the isolation membrane is less than or equal to the first dimension. In this way, in the formed electrode assembly, the two boundary lines of the first flow zone along the first direction can not exceed the corresponding ends of the anode electrode piece along the first direction, that is, the two ends of the anode electrode piece along the first direction correspond to the first barrier area. In this way, no matter the dimension of the cathode electrode piece along the first direction is greater than or equal to or less than the dimension of the anode electrode piece along the first direction, or in other words, the dimension of the first flow zone along the first direction is less than or equal to or greater than the second dimension, the problem of lithium plating can be avoided by the first barrier area, thereby reducing the dimensional requirements for the anode electrode piece and the cathode electrode piece during the processing, thereby reducing the cost of using X-rays for detection and improving the processing efficiency of the electrode assembly.

[0010] In some embodiments, the first barrier zone includes a first sub-region and a second sub-region distributed along the first direction and respectively located on both sides of the first flow zone, and the size of the first sub-region and / or the second sub-region along the first direction ranges from [2mm, 3mm].

[0011] The size of the first sub-region and / or the second sub-region along the first direction should not be set too large to avoid increasing costs and causing waste; but it should not be set too small, which will increase the difficulty of spraying or scraping the insulating material, and in the process of processing the electrode assembly, it is easy to affect the performance of the first barrier area due to errors and other reasons.

[0012] In some embodiments, a size of the first sub-region along the first direction is equal to a size of the second sub-region along the first direction, so that the isolation film is axisymmetric, which facilitates subsequent processing of the electrode assembly.

[0013] In some embodiments, a dimension of the first circulation area along the first direction is smaller than or equal to the second dimension to avoid lithium plating.

[0014] In some embodiments, the first surface is the surface of the isolation film facing the cathode electrode piece. Since burrs are more likely to appear when the tabs of the cathode electrode piece are die-cut, the first barrier area is provided on the surface facing the cathode electrode piece, which can avoid lithium deposition and reduce the possibility of burrs piercing the isolation film.

[0015] In some embodiments, the second surface of the isolation membrane includes a second flow area and a second barrier area. The second surface is arranged opposite to the first surface. The second barrier area is formed by spraying or scraping an insulating material on the edge areas on both sides along the first direction of the second surface. The second flow area is the area on the second surface except the second barrier area. The second flow area is used to pass ions in the electrolyte, and the second barrier area is used to block ions in the electrolyte.

[0016] The first barrier region and the second barrier region are respectively arranged on the two surfaces of the isolation membrane, which can effectively avoid the problem of lithium plating and can further increase the thickness of the two ends of the isolation membrane, that is, increase the strength of the two ends of the isolation membrane, thereby preventing burrs from piercing the isolation membrane and avoiding short circuits, thereby further improving the performance of the electrode assembly.

[0017] In some embodiments, the dimension of the second flow zone along the first direction is less than or equal to the first dimension, and the first dimension is the dimension of the anode electrode isolated by the isolation membrane along the first direction to avoid lithium deposition.

[0018] In some embodiments, the second barrier zone includes a third sub-region and a fourth sub-region distributed along the first direction and respectively located on both sides of the second flow zone, and the size of the third sub-region and / or the fourth sub-region along the first direction ranges from [2mm, 3mm].

[0019] The size of the third sub-region and / or the fourth sub-region along the first direction should not be set too large to avoid increasing costs and causing waste; but it should not be set too small, which will increase the difficulty of spraying or scraping the insulating material, and in the process of processing the electrode assembly, it is easy to affect the performance of the second barrier area due to errors and other reasons.

[0020] In some embodiments, a size of the third sub-region along the first direction is equal to a size of the fourth sub-region along the first direction, so that the isolation film is axisymmetric, which facilitates subsequent processing of the electrode assembly.

[0021] In some embodiments, two boundary lines of the second circulation area along the first direction are respectively flush with corresponding boundary lines of the first circulation area along the first direction. In this way, the two surfaces of the isolation film are consistent, and when processing the electrode assembly, there is no need to distinguish the directions of the two surfaces of the isolation film, which is more convenient for processing and improves processing efficiency.

[0022] In some embodiments, the insulating material is aluminum oxide and / or silicon dioxide.

[0023] In some embodiments, the material of the flow-through area includes at least one of the following: polypropylene PP, polyethylene PE, and polyvinylidene fluoride PVDF.

[0024] In a second aspect, a motor assembly is provided, comprising: an anode pole piece; a cathode pole piece; and an isolation membrane as described in the first aspect or any one of the implementations of the first aspect, wherein the isolation membrane is arranged between the anode pole piece and the cathode pole piece to isolate the anode pole piece from the cathode pole piece.

[0025] In some embodiments, two boundary lines of the first circulation zone along the first direction do not exceed the corresponding ends of the anode electrode sheet along the first direction to avoid lithium deposition.

[0026] In some embodiments, the second surface of the isolation membrane includes a second flow area and a second barrier area, the second surface is arranged opposite to the first surface, the second barrier area is formed by spraying or scraping an insulating material on the edge areas on both sides along the first direction on the second surface, the second flow area is the area on the second surface except the second barrier area, the second flow area is used to pass ions in the electrolyte, and the second barrier area is used to block ions in the electrolyte, and the two boundary lines of the second flow area along the first direction do not exceed the corresponding ends of the anode electrode along the first direction to avoid lithium precipitation.

[0027] In some embodiments, both ends of the cathode electrode sheet along the first direction are flush with the corresponding ends of the anode electrode sheet along the first direction, thereby avoiding lithium deposition and reducing the cost of the electrode assembly.

[0028] In some embodiments, the electrode assembly is formed by winding the anode electrode sheet, the separator, and the cathode electrode sheet around a winding axis, and the first direction is the direction of the winding axis.

[0029] In some embodiments, the electrode assembly is a plurality of the first anode plates, the isolation membranes, and a plurality of the second cathode plates alternately stacked along a second direction, and the second direction is perpendicular to the first direction.

[0030] In a third aspect, a battery cell is provided, comprising: the electrode assembly described in the second aspect or any one embodiment of the second aspect.

[0031] In a fourth aspect, a battery is provided, comprising: the battery cell described in the third aspect.

[0032] In a fifth aspect, an electrical device is provided, comprising: the battery described in the fourth aspect, wherein the battery is used to provide electrical energy to the electrical device.

[0033] In some embodiments, the electrical equipment is a vehicle, a ship or a spacecraft.

[0034] In a sixth aspect, a method for preparing an isolation membrane of an electrode assembly is provided, comprising: setting a mask plate on the first surface of the isolation membrane to be treated, wherein the two ends of the isolation membrane to be treated along the first direction respectively extend beyond the corresponding ends of the mask plate along the first direction, and the area covered by the mask plate is a first flow zone of the first surface, and the first flow zone is used for passing ions in the electrolyte, and the first direction is perpendicular to the extension direction of the isolation membrane to be treated; spraying or scraping an insulating material on the parts of the two ends of the isolation membrane to be treated that extend beyond the mask plate along the first direction to obtain a first barrier zone of the first surface, and the first barrier zone is used to block ions in the electrolyte; and removing the mask plate to obtain the isolation membrane of the electrode assembly.

[0035] In some embodiments, the mask plate is a polyethylene terephthalate (PET) film.

[0036] In a seventh aspect, a device for preparing an isolation membrane for an electrode assembly is provided, comprising a module for executing the method of the sixth aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a schematic diagram of the structure of a traditional electrode assembly;

[0038] Figure 2 is a structural schematic diagram of a vehicle disclosed in an embodiment of the present application;

[0039] Figure 3 is a partial schematic diagram of an isolation membrane disclosed in one embodiment of the present application;

[0040] Figure 4 is a schematic diagram of a separator for preparing an electrode assembly disclosed in one embodiment of the present application;

[0041] Figure 5 is a schematic diagram of a partially unfolded electrode assembly disclosed in an embodiment of the present application;

[0042] Figure 6 is a front view of a partially unfolded electrode assembly disclosed in an embodiment of the present application;

[0043] Figures 7 to 12 are several possible schematic diagrams of local cross-sections along the thickness direction of the electrode assembly disclosed in the embodiments of the present application;

[0044] Fig.13 is another partial schematic diagram of an isolation membrane disclosed in one embodiment of the present application;

[0045] Figures 14 to 17 are several possible schematic diagrams of a local cross section along the thickness direction of another electrode assembly disclosed in an embodiment of the present application;

[0046] Fig.18 is a schematic flow chart of a method for preparing a separator of an electrode assembly disclosed in one embodiment of the present application;

[0047] Fig.19 It is a schematic block diagram of an apparatus for preparing an isolation membrane of an electrode assembly disclosed in one embodiment of the present application.

[0048] In the drawings, the drawings are not drawn to scale. DETAILED DESCRIPTION

[0049] The technical solutions in the embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0050] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0051] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by technicians in the technical field of this application; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned drawings and any variations thereof are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship.

[0052] Reference to "embodiments" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0053] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "attached" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0054] The term "and / or" in this application is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this application generally indicates that the associated objects before and after are in an "or" relationship.

[0055] In the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary descriptions and should not constitute any limitation to the present application.

[0056] The term "multiple" as used in this application refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple sheets" refers to more than two sheets (including two sheets).

[0057] The battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity. For example, the battery mentioned in the present application may include a battery module or a battery pack. The battery generally includes a box for encapsulating one or more battery cells. The box can prevent liquid or other foreign matter from affecting the charging or discharging of the battery cells.

[0058] In the present application, battery cells may include lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries or magnesium-ion batteries, etc., and the embodiments of the present application do not limit this. Battery cells may be cylindrical, flat, rectangular or other shapes, etc., and the embodiments of the present application do not limit this. Battery cells are generally divided into three types according to the packaging method: cylindrical battery cells, square battery cells and soft-pack battery cells, and the embodiments of the present application do not limit this.

[0059] The battery cell includes an electrode assembly and an electrolyte. The electrode assembly is composed of a cathode electrode sheet, an anode electrode sheet and a separator. The battery cell mainly relies on the movement of metal ions between the cathode electrode sheet and the anode electrode sheet to work. The cathode electrode sheet includes a cathode current collector and a cathode active material layer. The cathode active material layer is coated on the surface of the cathode current collector. The cathode current collector not coated with the cathode active material layer protrudes from the cathode current collector coated with the cathode active material layer. The cathode current collector not coated with the cathode active material layer serves as a cathode tab. Taking lithium-ion batteries as an example, the material of the cathode current collector may be aluminum, and the cathode active material may be lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganese oxide, etc. The anode electrode sheet includes an anode current collector and an anode active material layer. The anode active material layer is coated on the surface of the anode current collector. The anode current collector not coated with the anode active material layer protrudes from the anode current collector coated with the anode active material layer. The anode current collector not coated with the anode active material layer serves as an anode tab. The material of the anode current collector may be copper, and the anode active material may be carbon or silicon, etc. In order to ensure that a large current can pass without melting, the number of cathode tabs is multiple and stacked together, and the number of anode tabs is multiple and stacked together. The material of the isolation film can be polypropylene (PP) or polyethylene (PE). In addition, the electrode assembly can be a winding structure or a laminated structure, and the embodiments of the present application are not limited thereto.

[0060] There are many disadvantages in the traditional processing method of electrode components. Figure 1 A schematic diagram of the structure of a conventional electrode assembly 100 is shown. Figure 1 As shown, a wound electrode assembly 100 is taken as an example for explanation, and, Figure 1 The left side of the figure is a schematic diagram of a partially unfolded electrode assembly 100. Figure 1As shown, the electrode assembly 100 includes two tabs 104 and 105, for example, the two tabs 104 and 105 can be a cathode tab and an anode tab, respectively, wherein the anode tab is connected to the anode tab 102, and the cathode tab is connected to the cathode tab 101. Here, the two tabs 104 and 105 are respectively located at two ends of the electrode assembly 100 along the winding axis X as an example for description.

[0061] like Figure 1 As shown, the electrode assembly 100 is formed by winding a cathode electrode piece 101, an anode electrode piece 102 and two insulating films 103, wherein the insulating film 103 is used to isolate the cathode electrode piece 101 and the anode electrode piece 102. Specifically, the insulating film 103 is a porous and electronically insulating material, and the main function of the insulating film 103 is electronic insulation and conduction of ions in the electrolyte. For example, the insulating film 103 in the lithium battery can allow lithium ions in the electrolyte to pass through to prevent the cathode electrode piece 101 and the anode electrode piece 102 from overlapping and short-circuiting.

[0062] like Figure 1 As shown, in order to ensure that the cathode electrode piece 101 and the anode electrode piece 102 will not overlap and short-circuit, the length of the insulating film 103 along the winding axis X of the electrode assembly 100 and along the winding direction Y of the electrode assembly 100 is greater than the length of the cathode electrode piece 101 and the length of the anode electrode piece 102. In addition, the anode electrode piece 102 in the electrode assembly 100 is usually configured to cover the cathode electrode piece 101, and the excess portion is to prevent the anode electrode piece 102 from lithium deposition and to prevent the burrs generated when the tabs 104 and 105 are formed by die cutting from piercing the insulating film 103.

[0063] However, during the production process, along the winding axis X of the electrode assembly 100, it is very likely that the anode plate 102 cannot wrap around the cathode plate 101 or the anode plate 102 wraps around the cathode plate 101 in a poor size, especially when the size difference between the two is small. At present, in order to prevent such poor size phenomenon in the manufacturing process, X-ray online detection is usually used, but X-ray online detection has the problems of time-consuming, low efficiency, and increased manufacturing cost. In addition, it can only be detected when the size difference between the cathode plate 101 and the anode plate 102 is greater than 1.0 mm, and the detection accuracy is low.

[0064] Therefore, the embodiment of the present application provides an isolation membrane of an electrode assembly, and the first surface of the isolation membrane includes a first circulation area and a first barrier area. The first barrier area is formed by spraying or scraping an insulating material on the edge areas on both sides of the first surface along the first direction, and the first direction is perpendicular to the extension direction of the isolation membrane, and the area on the first surface except the first barrier area is the first circulation area. The first circulation area can pass ions in the electrolyte, and the first barrier area can block the ions in the electrolyte. In this way, when the isolation membrane is used to wind and form an electrode assembly, since the edge area is provided with the first barrier area, the ions in the electrolyte can be blocked. Therefore, the length of the anode electrode sheet and the cathode electrode sheet along the first direction is no longer limited, and the lithium deposition problem of the anode electrode sheet can be avoided by the first barrier area. Even if the length of the anode electrode sheet along the first direction is less than or equal to the length of the cathode electrode sheet along the first direction, the lithium deposition problem of the anode electrode sheet can be avoided by the first barrier area, which reduces the processing difficulty and cost of the electrode assembly and improves the processing efficiency of the electrode assembly. Furthermore, the insulating material sprayed or scraped on the first barrier area can increase the strength of the area, effectively preventing burrs left after the pole piece is die-cut to form the pole ear from piercing the first barrier area of ​​the isolation membrane, thereby reducing the risk of short circuit caused by burrs piercing the isolation membrane.

[0065] The technical solutions described in the embodiments of the present application are applicable to various electrical devices using batteries.

[0066] Electrical equipment may be vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, electric tools, and the like. Vehicles may be fuel vehicles, gas vehicles, or new energy vehicles, and new energy vehicles may be pure electric vehicles, hybrid vehicles, or extended-range vehicles, and the like; spacecraft include airplanes, rockets, space shuttles, and spacecraft, and the like; electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, and the like; electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools, and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, and the like. The embodiments of the present application do not impose any special restrictions on the above-mentioned electrical equipment.

[0067] For the convenience of description, the following embodiments are described by taking the electric device as a vehicle as an example.

[0068] For example, Figure 2As shown, it is a structural schematic diagram of a vehicle 1 according to an embodiment of the present application. The vehicle 1 may be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A motor 40, a controller 30 and a battery 10 may be arranged inside the vehicle 1. The controller 30 is used to control the battery 10 to supply power to the motor 40. For example, a battery 10 may be arranged at the bottom, front or rear of the vehicle 1. The battery 10 may be used to supply power to the vehicle 1. For example, the battery 10 may be used as an operating power source for the vehicle 1, for the circuit system of the vehicle 1, for example, for the working power requirements during the start-up, navigation and operation of the vehicle 1. In another embodiment of the present application, the battery 10 may not only be used as an operating power source for the vehicle 1, but also as a driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0069] The battery 10 may include a box body, the interior of the box body is a hollow structure, and the hollow structure can be used to accommodate multiple battery cells. According to different power requirements, the number of battery cells in the battery 10 can be set to any value. Multiple battery cells can be connected in series, parallel or mixed to achieve a larger capacity or power. Since the number of battery cells included in each battery 10 may be large, in order to facilitate installation, the battery cells can be grouped, and each group of battery cells constitutes a battery module. The number of battery cells included in the battery module is not limited, and blocks can be set according to requirements. These battery modules can be connected in series, parallel or mixed.

[0070] Optionally, the battery 10 may also include other structures, which are not described one by one here. For example, the battery 10 may also include a busbar component, which is used to realize electrical connection between multiple battery cells, such as parallel connection, series connection, or mixed connection. Specifically, the busbar component can realize electrical connection between battery cells by connecting the electrode terminals of the battery cells. Further, the busbar component can be fixed to the electrode terminals of the battery cells by welding. The electrical energy of multiple battery cells can be further led out through the box through the conductive mechanism.

[0071] The electrode terminals on the battery cell are also used to electrically connect to the electrode assembly inside the battery cell to output the electrical energy of the battery cell. The electrode terminals may include a cathode electrode terminal and an anode electrode terminal, the cathode electrode terminal being used to electrically connect to the cathode tab, and the anode electrode terminal being used to electrically connect to the anode tab. The cathode electrode terminal may be directly connected to the cathode tab or indirectly connected, and the anode electrode terminal may be directly connected to the anode tab or indirectly connected. Exemplarily, the cathode electrode terminal is electrically connected to the cathode tab via a connecting member, and the anode electrode terminal is electrically connected to the anode tab via a connecting member.

[0072] The battery cell of the embodiment of the present application may include an external shell and an internal electrode assembly. The shell may be a hollow structure, which is used to accommodate the electrode assembly. The battery cell may be provided with one or more electrode assemblies according to the actual application. The electrode assembly is a component in the battery cell where an electrochemical reaction occurs. The electrode assembly may be a cylinder or a cuboid, etc., and the shape of the shell of the battery cell may be set accordingly according to the shape of the electrode assembly. The electrode assembly includes a connected pole ear and a main body, wherein the main body includes a cathode pole piece and an anode pole piece, and the pole ear of the electrode assembly may include a cathode pole ear and an anode pole ear. Specifically, the main body may be formed by stacking or winding a cathode pole piece coated with a cathode active material layer and an anode pole piece coated with an anode active material layer; the cathode pole ear may be formed by stacking a portion protruding from the cathode pole piece and not coated with the cathode active material layer, and the anode pole ear may be formed by stacking a portion protruding from the anode pole piece and not coated with the anode active material layer.

[0073] The electrode assembly of the embodiment of the present application may further include a separator, which is used to separate the anode electrode piece and the cathode electrode piece. Figure 3 FIG. 2 shows a partial schematic diagram of an isolation film 23 according to an embodiment of the present application. Figure 3 As shown, the first surface 23a of the isolation film 23 includes a first flow area 231 and a first barrier area 232. The first barrier area 232 is formed by spraying or scraping an insulating material on the edge areas on both sides of the first surface 23a along a first direction X. The first direction X is perpendicular to the extension direction Y of the isolation film 23. The first flow area 231 is the area on the first surface 23a except the first barrier area 232. The first flow area 231 is used to pass ions in the electrolyte, and the first barrier area 232 is used to block ions in the electrolyte. It should be understood that the isolation film 23 of the embodiment of the present application is a thin film structure. The isolation film 23 has two surfaces. The two surfaces are two surfaces arranged opposite to each other along the thickness direction of the isolation film 23. The first surface 23a can be any one of the two surfaces.

[0074] The isolation film 23 of the embodiment of the present application can be used to process an electrode assembly, and the isolation film 23 can be used to process multiple electrode assemblies by cutting during the processing. For example, the length of the extension direction Y of the isolation film 23 is usually much longer than the length of the first direction X, so that the isolation film 23 can be cut multiple times along the first direction X to form multiple isolation films 23 for multiple electrode assemblies, wherein the first direction X is perpendicular to the extension direction Y, and the thickness direction of the isolation film 23 is perpendicular to the first direction X and the extension direction Y of the isolation film 23.

[0075] The isolation film 23 of the embodiment of the present application can block the passage of electrons, so that when the isolation film 23 is disposed between the anode electrode piece and the cathode electrode piece, it can be used to achieve electrical isolation between the anode electrode piece and the cathode electrode piece to avoid short circuit. Specifically, the first flow area 231 of the isolation film 23 can block the passage of electrons to achieve electrical isolation between the anode electrode piece and the cathode electrode piece, but cannot block ions in the electrolyte, that is, ions in the electrolyte can pass through; different from this, the first blocking area 232 can block the passage of electrons to achieve electrical isolation between the anode electrode piece and the cathode electrode piece, and can also block ions in the electrolyte, that is, ions in the electrolyte cannot pass through the first blocking area 232.

[0076] Therefore, the separator 23 of the electrode assembly provided in the embodiment of the present application can block the ions in the electrolyte because the edge region is provided with the first barrier region 232. Therefore, when the separator 23 is used to wind the electrode assembly, the length of the anode electrode sheet and the cathode electrode sheet along the first direction X is no longer limited, and the lithium deposition problem of the anode electrode sheet can be avoided by the first barrier region 232. Regardless of whether the length of the anode electrode sheet along the first direction X is greater than, less than, or equal to the length of the cathode electrode sheet along the first direction X, the lithium deposition problem of the anode electrode sheet can be avoided by the first barrier region 232, which reduces the processing difficulty and cost of the electrode assembly and improves the processing efficiency of the electrode assembly. In addition, the insulating material sprayed or scraped on the first barrier region 232 can increase the strength of the region, effectively preventing the burrs left after the electrode sheet is die-cut to form the pole ear from piercing the first barrier region 232 of the separator 23, and reducing the risk of short circuit caused by the burrs piercing the separator 23.

[0077] It should be understood that Figure 3 As shown, the first barrier region 232 of the isolation film 23 is formed by spraying or scraping insulating material on the edge regions on both sides along the first direction X. Specifically, the first barrier region 232 includes a first subregion 2321 and a second subregion 2322 distributed along the first direction X and located on both sides of the first flow region 231 .

[0078] Optionally, the shape of the first sub-region 2321 and the shape of the second sub-region 2322 may be the same or different, and both may be set according to actual applications. Figure 3 As shown, considering that the isolation film 23 of the embodiment of the present application is a rectangle extending along the Y direction, correspondingly, the first sub-region 2321 and the second sub-region 2322 can also be rectangular and extend along the Y direction.

[0079] Optionally, the dimension L1 of the first sub-region 2321 along the first direction X and the dimension L2 of the second sub-region 2322 along the first direction X can be set according to actual applications, and the dimension L1 of the first sub-region 2321 along the first direction X and the dimension L2 of the second sub-region 2322 along the first direction X can be the same or different. Specifically, the dimension L1 of the first sub-region 2321 along the first direction X and the dimension L2 of the second sub-region 2322 along the first direction X should not be set too large, so as not to increase the cost and cause waste; but they should not be set too small, which will increase the difficulty of spraying or scraping the insulating material, and in the process of processing the electrode assembly, it is easy to affect the performance of the first barrier area 232 due to errors and other reasons. For example, the value range of the dimension L1 of the first sub-region 2321 along the first direction X can be [2mm, 3mm]; and / or the value range of the dimension L2 of the second sub-region 2322 along the first direction X can be [2mm, 3mm]. Figure 3 As shown, the embodiment of the present application is described by taking the example that the dimension L1 of the first sub-region 2321 along the first direction X is equal to the dimension L2 of the second sub-region 2322 along the first direction X, so that the isolation film 23 is axisymmetric, which is convenient for subsequent processing of the electrode assembly, but the embodiment of the present application is not limited to this.

[0080] In the embodiment of the present application, the first barrier region 232 of the isolation film 23 can be formed by spraying or scraping the insulating material, and the spraying or scraping of the insulating material to form the first barrier region 232 can be achieved in a variety of ways. For example, Figure 4 FIG. 2 shows a schematic diagram of a separator 23 for preparing an electrode assembly according to an embodiment of the present application. Figure 4 As shown, the insulating material can be sprayed or scraped through the mask plate 3.

[0081] Specifically, Figure 4 As shown, a mask plate 3 is set on the first surface 23a of the isolation film 23 to be treated, and the two ends of the isolation film 23 to be treated along the first direction X respectively exceed the corresponding ends of the mask plate 3 along the first direction X, and the area covered by the mask plate 3 is the first flow area 231 of the first surface 23a; on the parts of the two ends of the isolation film 23 to be treated that exceed the mask plate 3 along the first direction X, an insulating material is sprayed or scraped to obtain the first barrier area 232 of the first surface 23a; the mask plate 3 is removed to obtain the isolation film 23 of the electrode assembly.

[0082] Optionally, the material of the first circulation area 231 of the embodiment of the present application can be flexibly selected according to the actual application. For example, the material of the first circulation area 231 may include at least one of the following: PP, PE and polyvinylidene fluoride (PVDF). For example, along the thickness direction Z of the isolation membrane 23, the first circulation area 231 may include a multilayer structure, wherein the multilayer structure may include a substrate layer located in the center, the material of the substrate layer may include PP and PE, and the upper and lower surfaces of the substrate layer may be covered with PVDF glue, which is attached to the anode electrode sheet and the cathode electrode sheet through the PVDF glue to form an electrode assembly.

[0083] Optionally, the insulating material at the first barrier region 232 of the embodiment of the present application can also be flexibly selected according to practical applications. For example, the insulating material can be aluminum oxide and / or silicon dioxide.

[0084] Optionally, the material of the mask plate 3 of the embodiment of the present application can also be flexibly selected according to practical applications. For example, the mask plate 3 can be a polyethylene terephthalate (PET) film.

[0085] The embodiment of the present application forms the first barrier area 232 by spraying or scraping the insulating material. The whole process is simple and quick. For example, the first flow area 231 and the first barrier area 232 can be formed by blocking the mask plate 3. It is easy to implement and has low cost. In contrast, if the first barrier area 232 is formed by pasting insulating glue, since the insulating glue and the isolation film 23 are relatively soft, the isolation film 23 and the insulating glue are likely to wrinkle, thereby affecting the performance of the isolation film 23. Spraying or scraping the insulating material to form the first barrier area 232 can avoid these problems, and the process is easier to implement and more efficient. Moreover, when the first barrier region 232 is not provided, the isolation film 23 is usually very thin. For example, the thickness of the isolation film 23 is usually only 7-9 μm, while the thickness of the insulating glue is usually 30-50 μm. If the insulating glue is pasted on the isolation film 23, the area pasted with the insulating glue will protrude from other areas. After winding or stacking to form an electrode assembly, some areas of the electrode assembly will become loose, which will eventually lead to lithium deposition or black spots on the surface of the electrode piece, thereby affecting the performance of the battery cell. However, the first barrier region 232 of the embodiment of the present application is formed by spraying or scraping the insulating material, and its thickness is relatively small, which can well avoid the above problems and improve the performance of the battery cell.

[0086] It should be understood that the isolation film 23 of the embodiment of the present application can be used to form an electrode assembly. Figure 5 A schematic diagram of the structure of a partially unfolded electrode assembly 2 according to an embodiment of the present application is shown. Figure 6 Shows Figure 5 FIG. 2 is a front view of a partially unfolded electrode assembly 2. Figure 5 and Figure 6 As shown, the electrode assembly 2 includes an anode electrode piece 21, a cathode electrode piece 22 and two layers of isolation membranes 23. The isolation membrane 23 is arranged between the anode electrode piece 21 and the cathode electrode piece 22 to isolate the anode electrode piece 21 from the cathode electrode piece 22. The isolation membrane 23 can be as shown in the embodiment of the present application. Figure 3 and Figure 4 The isolation membrane shown.

[0087] Optionally, the electrode assembly 2 of the embodiment of the present application may be a winding type or a laminated type, but the embodiment of the present application is not limited thereto. Figure 5 and Figure 6 As shown, the electrode assembly 2 of the embodiment of the present application may be a wound electrode assembly. Specifically, the electrode assembly 2 is formed by winding the anode electrode sheet 21, the separator 23 and the cathode electrode sheet 22 around a winding axis, and the first direction X is the direction of the winding axis.

[0088] Alternatively, the electrode assembly 2 of the embodiment of the present application may also be a laminated electrode assembly. For example, the electrode assembly 2 is a plurality of anode pole pieces 21, a separator 23 and a plurality of cathode pole pieces 22 alternately stacked along the second direction Z, and the second direction Z is perpendicular to the first direction X, or in other words, the second direction Z is the thickness direction of the separator 23, and the separator 23 can be arranged between the anode pole piece 21 and the cathode pole piece 22 by repeatedly folding. For another example, the electrode assembly 2 may also be an anode pole piece 21, a separator 23 and a plurality of cathode pole pieces 22 alternately stacked along the second direction Z, wherein the anode pole piece 21 and the separator 23 are repeatedly folded to be stacked with the plurality of cathode pole pieces 22 to form the electrode assembly 2, and the embodiment of the present application is not limited thereto.

[0089] Optionally, Figure 5 and Figure 6 In the example, the two pole ears 211 and 221 of the electrode assembly 2 are located on the same end surface of the electrode assembly 2. Different from this, the two pole ears 211 and 221 of the electrode assembly 2 can also be located on different end surfaces, and the embodiments of the present application are not limited to this.

[0090] The isolation film 23 of the embodiment of the present application will be described in detail below in conjunction with specific embodiments.

[0091] Figures 7 to 12 Several possible schematic diagrams of partial cross-sections of the electrode assembly 2 along the thickness direction of the embodiment of the present application are respectively shown, wherein: Figures 7 to 12The anode electrode sheet 21 and the cathode electrode sheet 22 are respectively shown in the electrode assembly 2 and are disposed between the three-layer separator 23. The three-layer separator 23 is used as an example for description. Figures 7 to 12 As shown, since the actual thickness of the anode electrode piece 21, the cathode electrode piece 22 and the isolation film 23 is relatively small, for the convenience of description and understanding, Figure 7 and Fig.12 The thicknesses of the anode electrode piece 21 , the cathode electrode piece 22 and the isolation film 23 are magnified.

[0092] like Figures 7 to 12 As shown, the isolation film 23 of the embodiment of the present application satisfies: the dimension L231 of the first circulation area 231 along the first direction X is less than or equal to the first dimension L21, and the first dimension L21 is the dimension L21 of the anode electrode piece 21 isolated by the isolation film 23 along the first direction X; the dimension L23 of the isolation film 23 along the first direction X is greater than the first dimension L21 and greater than the second dimension L22, and the second dimension L22 is the dimension L22 of the cathode electrode piece 22 isolated by the isolation film 23 along the first direction X. Specifically, the dimension L23 of the first isolation film 23 along the first direction X is greater than the first dimension L21 and greater than the second dimension L22, so that in the electrode assembly 2, the isolation film 23 can make the two ends of the anode electrode piece 21 along the first direction X and the two ends of the cathode electrode piece 22 along the first direction X not exceed the corresponding ends of the isolation film 23 along the first direction X, so as to ensure that the isolation film 23 can block the anode electrode piece 21 and the cathode electrode piece 22 to avoid short circuit.

[0093] In addition, the dimension L231 of the first circulation area 231 of the isolation membrane 23 along the first direction X is less than or equal to the first dimension L21. In this way, in the formed electrode assembly 2, the two boundary lines of the first circulation area 231 along the first direction X can not exceed the corresponding ends of the anode electrode sheet 21 along the first direction X, that is, the two ends of the anode electrode sheet 21 along the first direction X correspond to the first barrier area 232. In this way, no matter whether the dimension L22 of the cathode electrode sheet 22 along the first direction X is greater than, equal to, or less than the dimension L21 of the anode electrode sheet 21 along the first direction X, or in other words, the dimension L231 of the first circulation area 231 along the first direction X is less than, equal to, or greater than the second dimension L22, the problem of lithium deposition can be avoided by the first barrier area 232, thereby reducing the dimensional requirements for the anode electrode sheet 21 and the cathode electrode sheet 22 during processing, thereby reducing the cost of using X-rays for detection, and improving the processing efficiency of the electrode assembly 2.

[0094] Optionally, as an embodiment, Figure 7 and Figure 8As shown, the first surface 23a of the isolation film 23 is taken as the surface of the isolation film 23 facing the cathode electrode 22. The dimension L231 of the first flow area 231 along the first direction X may be less than or equal to the first dimension L21. For example, Figure 7 and Figure 8 For example, the dimension L231 of the first circulation area 231 along the first direction X is smaller than the first dimension L21. At this time, the two ends of the anode electrode 21 along the first direction X correspond to the first barrier area 232. The dimension L23 of the isolation film 23 along the first direction X is larger than the first dimension L21 and larger than the second dimension L22. At this time, Figure 7 As shown, the second dimension L22 is set to be larger than the first dimension L21, that is, the dimension L231 of the first flow area 231 along the first direction X is smaller than the second dimension L22, then the two ends of the cathode electrode piece 21 along the first direction X correspond to the first barrier area 232; or, the second dimension L22 can be set to be smaller than the first dimension L21, then the two ends of the cathode electrode piece 21 along the first direction X can correspond to the first barrier area 232, or, Figure 8 As shown, it corresponds to the first circulation area 231, or it can also be flush with the corresponding end of the first circulation area 231 along the first direction X; or, the second size L22 can also be set equal to the first size L21, that is, the size L231 of the first circulation area 231 along the first direction X is equal to the second size L22, then the two ends of the cathode electrode piece 21 along the first direction X and the two ends of the anode electrode piece 22 along the first direction X can be flush with each other. Due to the existence of the first barrier area 232, there will be no risk of lithium deposition in the above-mentioned situations, but the size requirements for the anode electrode piece 21 and the cathode electrode piece 22 are reduced, which also reduces the cost of using X-rays for detection, thereby improving the processing efficiency of the electrode assembly 2. In addition, considering that burrs are more likely to occur when die-cutting to form the cathode ear, the first barrier area 232 is set on the surface facing the cathode electrode piece 22. Compared with the case where the first barrier area 232 is set on the surface facing the anode electrode piece 21, the possibility of the isolation film 23 being pierced by burrs can be reduced to a greater extent.

[0095] Optionally, as another embodiment, Fig. 9 and Fig.10 As shown, the first surface 23a of the isolation film 23 is taken as an example as the surface of the isolation film 23 facing the anode electrode 21. Figure 7 and Figure 8 Similarly, the dimension L231 of the first circulation area 231 along the first direction X may be less than or equal to the first dimension L21. For example, Fig. 9 and Fig.10For example, the dimension L231 of the first circulation area 231 along the first direction X is smaller than the first dimension L21. At this time, the two ends of the anode electrode 21 along the first direction X correspond to the first barrier area 232. The dimension L23 of the isolation film 23 along the first direction X is larger than the first dimension L21 and larger than the second dimension L22. At this time, it can be as follows Fig. 9 As shown in the figure, the second size L22 is set to be larger than the first size L21, then both ends of the cathode electrode piece 21 along the first direction X can correspond to the first blocking area 232; or, the second size L22 can be set to be smaller than the first size L21, then both ends of the cathode electrode piece 21 along the first direction X can correspond to the first blocking area 232, or Fig.10 The first barrier region 232 corresponds to the first circulation region 231, or may be flush with the corresponding end of the first circulation region 231 along the first direction X; or, the second dimension L22 may be set equal to the first dimension L21, so that the two ends of the cathode electrode piece 21 along the first direction X and the two ends of the anode electrode piece 22 along the first direction X may be flush with each other. Due to the presence of the first barrier region 232, there is also no risk of lithium deposition, and the size requirements for the anode electrode piece 21 and the cathode electrode piece 22 are reduced, thereby improving the processing efficiency of the electrode assembly 2.

[0096] It should be understood that when the first dimension L21 is equal to the second dimension L22, the two ends of the anode electrode plate 21 along the first direction X can be flush with the corresponding ends of the cathode electrode plate L22 along the first direction X, respectively. Then, compared with the uneven situation, the capacity of the electrode assembly 2 can be increased. For example, taking the case where the dimension L21 of the anode electrode sheet 21 along the first direction X is equal to the first circulation area 231, that is, the two ends of the anode electrode sheet 21 along the first direction X are flush with the corresponding ends of the first circulation area 231 along the first direction X, at this time, assuming that the difference between the dimension L21 of the anode electrode sheet 21 along the first direction X and the dimension L22 of the cathode electrode sheet L22 along the first direction X is 4 mm, and assuming that the dimension L22 of the cathode electrode sheet L22 along the first direction X is smaller and is 100 mm, at this time, the capacity of the battery cell formed by the electrode assembly 2 is calculated according to 100 Ah, then when the second dimension L22 is set to be equal to the first dimension L21, the dimension L22 of the cathode electrode sheet L22 along the first direction X can be increased by 4 mm, and the two ends of the anode electrode sheet 21 along the first direction X can be achieved. Flush with the corresponding ends of the cathode electrode sheet L22 along the first direction X, and the capacity of the corresponding battery cell can be increased by 4 Ah.

[0097] Alternatively, if Figures 7 to 10As shown, although the first barrier region 232 is formed by spraying or scraping an insulating material, the thickness of the first barrier region 232 can be very small, but it still slightly protrudes from the surface of the first circulation region 231, resulting in a gap between the isolation film 23 and the anode electrode sheet 21 or the cathode electrode sheet 22. In order to reduce the gap, the first barrier region 232 can be set flush with the first circulation region 231 in the thickness direction Z. Specifically, considering that PVDF glue is usually provided on both surfaces of the isolation membrane 23 for contacting and fixing the anode electrode 21 and the cathode electrode 22, the PVDF glue can be provided in the first circulation area 231, while the PVDF glue is not provided in the first barrier area 232, and the thickness of the insulating material sprayed or scraped in the first barrier area 232 is equal to the thickness of the PVDF glue in the first circulation area 231. In this way, the first barrier area 232 can be flush with the first circulation area 231, avoiding the gap between the anode electrode 21 and the isolation membrane 23 and the gap between the cathode electrode 22 and the isolation membrane 23, thereby preventing the electrode assembly 2 from being loose.

[0098] Optionally, in the case where the first barrier region 232 is flush with the first circulation region 231 in the thickness direction Z, the isolation film 23 also satisfies: the dimension L231 of the first circulation region 231 along the first direction X is less than or equal to the first dimension L21; the dimension L23 of the isolation film 23 along the first direction X is greater than the first dimension L21 and greater than the second dimension L22, so as to avoid lithium deposition. For example, Fig.11 and Fig.12 In the figure, the first surface 23a of the isolation film 23 is taken as the surface of the isolation film 23 facing the cathode electrode 22. Fig.11 As shown, the dimension L231 of the first circulation area 231 along the first direction X may be smaller than the first dimension L21, and the first dimension L21 may be smaller than the second dimension L22, that is, the dimension L231 of the first circulation area 231 along the first direction X is smaller than the second dimension L22, then both ends of the anode electrode piece 21 along the first direction X and both ends of the cathode electrode piece 22 along the first direction X correspond to the first barrier area 232. For another example, Fig.12 As shown, the dimension L231 of the first circulation area 231 along the first direction X may also be equal to the first dimension L21 and equal to the second dimension L22, then the two ends of the cathode electrode piece 22 along the first direction X may be flush with the corresponding ends of the anode electrode piece 21 along the first direction X, and also flush with the corresponding ends of the first circulation area 231 along the first direction X, respectively. Fig.11 and Fig.12 The situations shown can all avoid the problem of lithium plating.

[0099] It should be understood that the above description is based on the example of setting the first flow area 231 and the first barrier area 232 on the first surface 23a of the isolation film 23. When the first flow area 231 and the first barrier area 232 are only set on the first surface 23a, the processing process is simple and the cost is low. However, similar to the first surface 23a, the second flow area 233 and the second barrier area 234 can be set on the second surface 23b of the isolation film 23.

[0100] Fig.13 FIG. 2 shows a partial schematic diagram of an isolation film 23 according to an embodiment of the present application. Fig.13 As shown, the second surface 23b of the isolation membrane 23 includes a second flow area 233 and a second barrier area 234. The second surface 23b is arranged opposite to the first surface 23a. The second barrier area 234 is formed by spraying or scraping an insulating material on the edge areas on both sides of the second surface 23b along the first direction X. The second flow area 233 is the area on the second surface 23b except the second barrier area 234. The second flow area 233 is used to pass ions in the electrolyte, and the second barrier area 234 is used to block ions in the electrolyte.

[0101] The second surface 23b of the embodiment of the present application is a surface disposed opposite to the first surface 23a. For example, if the first surface 23a is the surface of the separator 23 facing the anode electrode piece 21, the second surface 23b is the surface of the separator 23 facing the cathode electrode piece 22; on the contrary, if the first surface 23a is the surface of the separator 23 facing the cathode electrode piece 22, the second surface 23b is the surface of the separator 23 facing the anode electrode piece 21.

[0102] The first barrier region 232 and the second barrier region 234 are respectively arranged on the two surfaces 23a and 23b of the isolation membrane 23, which can effectively avoid the problem of lithium plating and increase the thickness of the two ends of the isolation membrane 23, that is, increase the strength of the two ends of the isolation membrane 23, thereby preventing burrs from piercing the isolation membrane 23 and short circuit, thereby further improving the performance of the electrode assembly 2.

[0103] It should be understood that the configuration of the second surface 23b of the embodiment of the present application is similar to the configuration of the first surface 23a, wherein the second circulation area 233 corresponds to the first circulation area 231 and is applicable to the description of the first circulation area 231; and the second barrier area 234 corresponds to the first barrier area 232 and is applicable to the description of the first barrier area 232, which will not be repeated here for the sake of brevity.

[0104] For example, the second circulation area 233 and the second barrier area 234 can also be obtained by processing the mask plate 3. The insulating material of the second barrier area 234 can be selected according to the actual application, for example, the insulating material can be aluminum oxide and / or silicon dioxide, and the insulating material of the second barrier area 234 and the insulating material of the first barrier area 232 can be the same or different. The material of the second circulation area 233 can also be selected according to the actual application, for example, the material of the second circulation area 233 includes at least one of the following: PP, PE and PVDF, and the materials of the second circulation area 233 and the first circulation area 231 can also be the same or different, and the embodiments of the present application are not limited thereto.

[0105] like Fig.13 As shown, the second barrier region 234 includes a third sub-region 2341 and a fourth sub-region 2342 distributed along the first direction X and located on both sides of the second flow region 233. Moreover, the dimension L3 of the third sub-region 2341 along the first direction X and the dimension L4 of the fourth sub-region 2342 along the first direction X can be set according to actual applications. Specifically, similar to the first sub-region 2321 and the second sub-region 2322, the dimension L3 of the third sub-region 2341 along the first direction X and the dimension L4 of the fourth sub-region 2342 along the first direction X should not be set too large, so as not to increase the cost and cause waste; but it should not be set too small, which will increase the difficulty of spraying or scraping the insulating material, and in the process of processing the electrode assembly 2, it is easy to affect the performance of the second barrier region 234 due to errors and other reasons. For example, the value range of the dimension L3 of the third sub-region 2341 along the first direction X may be [2 mm, 3 mm], and / or the value range of the dimension L4 of the fourth sub-region 2342 along the first direction X may be [2 mm, 3 mm]. Optionally, the dimension L3 of the third sub-region 2341 along the first direction X may be the same as or different from the dimension L4 of the fourth sub-region 2342 along the first direction X; the dimension L3 of the third sub-region 2341 along the first direction X may be the same as or different from the dimension L1 of the first sub-region 2321 along the first direction X; the dimension L4 of the fourth sub-region 2342 along the first direction X may be the same as or different from the dimension L2 of the second sub-region 2322 along the first direction X, and the embodiments of the present application are not limited thereto.

[0106] In the following, an example is taken in which the two boundary lines of the second circulation area 233 along the first direction X are respectively flush with the corresponding boundary lines of the first circulation area 231 along the first direction X, that is, an example is taken in which the size L1 of the first sub-area 2321 along the first direction X, the size L2 of the second sub-area 2322 along the first direction X, the size L3 of the third sub-area 2341 along the first direction X and the size L4 of the fourth sub-area 2342 along the first direction X are all the same. Such a setting facilitates the processing of the isolation membrane 23, so that the two surfaces 23a and 23b of the isolation membrane 23 are completely consistent, and the isolation membrane 23 is symmetrical along the center line axis of the isolation membrane 23 perpendicular to the first direction X. When processing the electrode assembly 2, there is no need to distinguish the two surfaces 23a and 23b of the isolation membrane 23 and the specific direction, which is more convenient for processing and improves processing efficiency.

[0107] Figures 14 to 17 Several other possible schematic diagrams of partial cross-sections of the electrode assembly 2 along the thickness direction of the embodiment of the present application are respectively shown, wherein: Figures 14 to 17 The electrode assembly 2 includes an anode electrode sheet 21 and a cathode electrode sheet 22 disposed between three layers of separators 23, and the three layers of separators 23 are used as an example for illustration. Figures 14 to 17 The first surface 23a is the surface of the separator 23 facing the cathode electrode piece 22, and the second surface 23b is the surface of the separator 23 facing the anode electrode piece 21. However, the following description is also applicable to the case where the first surface 23a is the surface of the separator 23 facing the anode electrode piece 21 and the second surface 23b is the surface of the separator 23 facing the cathode electrode piece 22, and will not be repeated here. Figures 7 to 12 Similarly, since the actual thickness of the anode electrode piece 21, the cathode electrode piece 22 and the isolation film 23 is relatively small, for the convenience of description and understanding, Fig.14 and Fig.17 The thickness of the anode electrode piece 21 , the cathode electrode piece 22 and the isolation film 23 are also enlarged.

[0108] like Figures 14 to 17As shown, the dimension L233 of the second circulation area 233 along the first direction X is less than or equal to the first dimension L21, and the first dimension L21 is the dimension L21 of the anode electrode piece 21 isolated by the isolation film 23 along the first direction X. Specifically, the second circulation area 233 is similar to the first circulation area 231, and the dimension L233 of the second circulation area 233 along the first direction X is set to be less than or equal to the first dimension L21, so that both ends of the anode electrode piece 21 along the first direction X correspond to the second barrier area 234, so that no matter the dimension L22 of the cathode electrode piece 21 along the first direction X is greater than or equal to or less than the dimension L21 of the anode electrode piece 21 along the first direction X, or in other words, the dimension L233 of the second circulation area 233 along the first direction X is less than or equal to or greater than the second dimension L22, the problem of lithium deposition can be avoided by the second barrier area 234, which reduces the dimensional requirements for the anode electrode piece 21 and the cathode electrode piece 22 during the processing, thereby reducing the cost of using X-rays for detection and improving the processing efficiency of the electrode assembly 2.

[0109] Optionally, as an embodiment, Fig.14 and Fig.15 As shown, the dimension L233 of the second circulation area 233 along the first direction X of the embodiment of the present application may be smaller than the first dimension L21, and the boundary lines of both ends of the second circulation area 233 along the first direction X may not exceed the anode electrode sheet, or both ends of the anode electrode sheet 21 along the first direction X correspond to the second barrier area 234. The second dimension L22 may be as follows: Fig.14 As shown, the second dimension L22 may be set to be larger than the first dimension L21, and the two ends of the cathode electrode piece 22 along the first direction X may also correspond to the second barrier area 234; or, the second dimension L22 may be set to be smaller than the first dimension L21, and the two ends of the cathode electrode piece 22 along the first direction X may correspond to the second barrier area 234, or Fig.15 The illustrated embodiment corresponds to the second circulation area 233, or is flush with the corresponding end of the second circulation area 233. Due to the existence of the first barrier area 232 and the second barrier area 234, there is no risk of lithium deposition in the above-mentioned situations, but the size requirements for the anode electrode piece 21 and the cathode electrode piece 22 are reduced, which reduces the cost of using X-rays for detection, thereby improving the processing efficiency of the electrode assembly 2.

[0110] Optionally, as another embodiment, Fig.16 and Fig.17 As shown, the first size L21 of the embodiment of the present application can be equal to the second size L22. Fig.16As shown, the dimension L233 of the second flow area 233 along the first direction X can be smaller than the first dimension L21 and smaller than the second dimension L22, then both ends of the anode electrode piece 21 along the first direction X and both ends of the cathode electrode piece 22 along the first direction X correspond to the second barrier area 234; for another example, Fig.17 As shown, the dimension L233 of the second circulation area 233 along the first direction X can be equal to the first dimension L21 and equal to the second dimension L22, then the two ends of the second circulation area 233 along the first direction X are respectively flush with the corresponding ends of the anode electrode 21 along the first direction X, and are also respectively flush with the corresponding ends of the cathode electrode 22 along the first direction X.

[0111] on the one hand, Fig.16 and Fig.17 The embodiment shown is compared to Fig.14 and Fig.15 In the case where the first dimension L21 shown may not be equal to the second dimension L22, since both ends of the anode electrode sheet 21 along the first direction X may be flush with the corresponding ends of the cathode electrode sheet 22 along the first direction X, and there is no size difference between the two, when the capacity of the electrode assembly 2 is consistent, the cost can be reduced; or, when the cost is consistent, the capacity of the electrode assembly 2 can be increased. For example, taking the case where the dimension L21 of the anode electrode sheet 21 along the first direction X is equal to the second circulation area 233 as an example, that is, the two ends of the anode electrode sheet 21 along the first direction X are flush with the corresponding ends of the second circulation area 233 along the first direction X. At this time, assuming that the difference between the dimension L21 of the anode electrode sheet 21 along the first direction X and the dimension L22 of the cathode electrode sheet L22 along the first direction X is 4 mm, and assuming that the dimension L22 of the cathode electrode sheet L22 along the first direction X is smaller and is 100 mm, at this time, the capacity of the battery cell formed by the electrode assembly 2 is calculated according to 100 Ah, then when the second dimension L22 is set to be equal to the first dimension L21, the dimension L22 of the cathode electrode sheet L22 along the first direction X can be increased by 4 mm, and the two ends of the anode electrode sheet 21 along the first direction X can be flush with the corresponding ends of the cathode electrode sheet L22 along the first direction X, and the capacity of the corresponding battery cell can be increased by 4 Ah.

[0112] On the other hand, in contrast Fig.16 and Fig.17 ,like Fig.16 and Fig.17 The dimension L233 of the second circulation area 233 along the first direction X is the same, then Fig.16 and Fig.17 The capacity of the middle electrode assembly 2 can be guaranteed to be the same, but Fig.17 The dimension L22 of the cathode electrode piece 22 along the first direction X and the dimension L21 of the anode electrode piece 21 along the first direction X required by the illustrated embodiment are smaller, which can further reduce the cost.

[0113] The electrode assembly 2 and the isolation membrane 23 of the embodiment of the present application are described above. The method and equipment for preparing the isolation membrane 23 of the electrode assembly 2 of the embodiment of the present application will be described below. For the parts not described in detail, please refer to the aforementioned embodiments.

[0114] Fig.18 FIG. 3 is a schematic flow chart of a method 300 for preparing a separator 23 of an electrode assembly 2 according to an embodiment of the present application. Fig.18 As shown, the method 300 may include: S310, setting a mask plate 3 on the first surface 23a of the isolation film 23 to be treated, the two ends of the isolation film 23 to be treated along the first direction X respectively exceed the corresponding ends of the mask plate 3 along the first direction X, and the area covered by the mask plate 3 is the first flow area 231 of the first surface 23a, and the first flow area 231 is used for passing ions in the electrolyte, and the first direction X is perpendicular to the extension direction of the isolation film 23 to be treated; S320, spraying or scraping an insulating material on the parts of the two ends of the isolation film 23 to be treated along the first direction X that exceed the mask plate 3 to obtain the first barrier area 232 of the first surface 23a, and the first barrier area 232 is used to block the ions in the electrolyte; S330, removing the mask plate 3 to obtain the isolation film 23 of the electrode assembly.

[0115] In some embodiments, the mask plate 3 is a PET film.

[0116] Fig.19 FIG. 4 is a schematic block diagram of an apparatus 400 for preparing a separator 23 of an electrode assembly 2 according to an embodiment of the present application. Fig.19 As shown, the device 400 may include: a setting module 410, used to set a mask plate 3 on the first surface 23a of the isolation film 23 to be treated, and the two ends of the isolation film 23 to be treated along the first direction X respectively exceed the corresponding ends of the mask plate 3 along the first direction X, and the area covered by the mask plate 3 is the first flow area 231 of the first surface 23a, and the first flow area 231 is used to pass ions in the electrolyte, and the first direction X is perpendicular to the extension direction of the isolation film 23 to be treated; a processing module 420, used to spray or scrape an insulating material on the parts of the isolation film 23 to be treated that exceed the mask plate 3 at both ends along the first direction X to obtain a first barrier area 232 of the first surface 23a, and the first barrier area 232 is used to block ions in the electrolyte; a removal module 430, used to remove the mask plate 3 to obtain the isolation film 23 of the electrode assembly.

[0117] Although the present application has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced with equivalents without departing from the scope of the present application. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A separator (23) of an electrode assembly, characterized in that: The first surface (23a) of the isolation film (23) includes a first flow region (231) and a first barrier region (232). The first barrier region (232) is formed by spraying or scraping an insulating material on both side edge regions along a first direction on the first surface (23a), the first direction being perpendicular to the extension direction of the isolation film (23), the first flow region (231) being the region on the first surface (23a) excluding the first barrier region (232), The first circulation area (231) is used for passing ions in the electrolyte, and the first barrier area (232) is used for blocking ions in the electrolyte; The dimension (L231) of the first circulation area (231) along the first direction is less than or equal to the first dimension (L21), and the first dimension (L21) is the dimension of the anode electrode separated by the isolation film (23) along the first direction. The dimension (L23) of the isolation film (23) along the first direction is larger than the first dimension (L21) and larger than a second dimension (L22), and the second dimension (L22) is the dimension of the cathode electrode piece isolated by the isolation film (23) along the first direction.

2. The isolation membrane (23) according to claim 1, characterized in that: The first barrier area (232) includes a first sub-area (2321) and a second sub-area (2322) distributed along the first direction and respectively located on both sides of the first flow area (231), and the size of the first sub-area (2321) and / or the second sub-area (2322) along the first direction has a value range of [2mm, 3mm].

3. The isolation membrane (23) according to claim 2, characterized in that: The size of the first sub-region (2321) along the first direction is equal to the size of the second sub-region (2322) along the first direction.

4. The isolation membrane (23) according to any one of claims 1 to 3, characterized in that: A dimension (L231) of the first circulation area (231) along the first direction is smaller than or equal to the second dimension (L22).

5. The isolation membrane (23) according to any one of claims 1 to 3, characterized in that: The first surface (23a) is the surface of the isolation film (23) facing the cathode electrode piece.

6. The isolation membrane (23) according to any one of claims 1 to 3, characterized in that: The second surface (23b) of the isolation membrane (23) comprises a second flow area (233) and a second barrier area (234); the second surface (23b) is arranged opposite to the first surface (23a); the second barrier area (234) is formed by spraying or scraping an insulating material on both side edge areas along the first direction of the second surface (23b); the second flow area (233) is the area on the second surface (23b) except the second barrier area (234); the second flow area (233) is used for passing ions in the electrolyte; and the second barrier area (234) is used for blocking ions in the electrolyte.

7. The isolation membrane (23) according to claim 6, characterized in that: The dimension (L233) of the second circulation area (233) along the first direction is less than or equal to the first dimension (L21), and the first dimension (L21) is the dimension of the anode electrode separated by the isolation film (23) along the first direction.

8. The isolation membrane (23) according to claim 7, characterized in that: The second barrier zone (234) includes a third sub-region (2341) and a fourth sub-region (2342) distributed along the first direction and respectively located on both sides of the second flow zone (233), and the size of the third sub-region (2341) and / or the fourth sub-region (2342) along the first direction has a value range of [2mm, 3mm].

9. The isolation membrane (23) according to claim 8, characterized in that: The size of the third sub-region (2341) along the first direction is equal to the size of the fourth sub-region (2342) along the first direction.

10. The isolation membrane (23) according to claim 6, characterized in that: Two boundary lines of the second circulation area (233) along the first direction are respectively flush with corresponding boundary lines of the first circulation area (231) along the first direction.

11. The isolation membrane (23) according to any one of claims 1 to 3, characterized in that: The insulating material is aluminum oxide and / or silicon dioxide.

12. The isolation membrane (23) according to any one of claims 1 to 3, characterized in that: The material of the circulation area includes at least one of the following: polypropylene PP, polyethylene PE and polyvinylidene fluoride PVDF.

13. An electrode assembly, characterized in that: include: Anode pole piece (21); Cathode pole piece (22); The isolation membrane (23) according to any one of claims 1 to 12, wherein the isolation membrane (23) is arranged between the anode electrode piece (21) and the cathode electrode piece (22) to isolate the anode electrode piece (21) from the cathode electrode piece (22).

14. The electrode assembly according to claim 13, characterized in that: The two boundary lines of the first circulation area (231) along the first direction do not exceed the corresponding ends of the anode electrode sheet (21) along the first direction.

15. The electrode assembly according to claim 13 or 14, characterized in that: The second surface (23b) of the isolation film (23) comprises a second flow area (233) and a second barrier area (234); the second surface (23b) is arranged opposite to the first surface (23a); the second barrier area (234) is formed by spraying or scraping an insulating material on both side edge areas along the first direction of the second surface (23b); the second flow area (233) is the area on the second surface (23b) other than the second barrier area (234); the second flow area (233) is used for passing ions in the electrolyte; the second barrier area (234) is used for blocking ions in the electrolyte; The two boundary lines of the second circulation area (233) along the first direction do not exceed the corresponding ends of the anode electrode sheet (21) along the first direction.

16. The electrode assembly according to claim 13 or 14, characterized in that: Both ends of the cathode electrode piece (22) along the first direction are respectively flush with corresponding ends of the anode electrode piece (21) along the first direction.

17. The electrode assembly according to claim 13 or 14, characterized in that: The electrode assembly is formed by winding the anode electrode sheet (21), the separator (23) and the cathode electrode sheet (22) around a winding axis, and the first direction is the direction of the winding axis.

18. The electrode assembly according to claim 13 or 14, characterized in that: The electrode assembly comprises a plurality of anode plates (21), a separation membrane (23) and a plurality of cathode plates (22) alternately stacked along a second direction, wherein the second direction is perpendicular to the first direction.

19. A battery cell, characterized in that: include: An electrode assembly according to any one of claims 13 to 18.

20. A battery, characterized in that: include: The battery cell according to claim 19.

21. An electrical equipment, characterized in that: include: The battery according to claim 20 is used to provide electrical energy to the electrical device.

22. A method for preparing a separator of an electrode assembly, characterized in that: include: A mask plate (3) is arranged on a first surface (23a) of a to-be-treated isolation film (23), two ends of the to-be-treated isolation film (23) along a first direction respectively extend beyond corresponding ends of the mask plate (3) along the first direction, an area covered by the mask plate (3) is a first flow area (231) of the first surface (23a), the first flow area (231) is used for passing ions in an electrolyte, and the first direction is perpendicular to an extension direction of the to-be-treated isolation film (23); Spraying or scraping insulating material on the portions of the isolation film (23) to be treated that extend beyond the mask plate (3) at both ends along the first direction, so as to obtain a first barrier region (232) on the first surface (23a), wherein the first barrier region (232) is used to block ions in the electrolyte; The mask plate (3) is removed to obtain the isolation membrane (23) of the electrode assembly, wherein the dimension (L231) of the first circulation area (231) along the first direction is less than or equal to the first dimension (L21), the first dimension (L21) is the dimension of the anode electrode piece isolated by the isolation membrane (23) along the first direction, the dimension (L23) of the isolation membrane (23) along the first direction is greater than the first dimension (L21) and greater than the second dimension (L22), the second dimension (L22) is the dimension of the cathode electrode piece isolated by the isolation membrane (23) along the first direction.

23. The method according to claim 22, characterized in that The mask plate (3) is a polyethylene terephthalate (PET) film.

24. A device for preparing a separator for an electrode assembly, characterized in that: include: A setting module is used to set a mask plate (3) on a first surface (23a) of a to-be-treated isolation membrane (23), wherein two ends of the to-be-treated isolation membrane (23) along a first direction respectively extend beyond corresponding ends of the mask plate (3) along the first direction, and an area covered by the mask plate (3) is a first flow area (231) of the first surface (23a), wherein the first flow area (231) is used for passing ions in an electrolyte, and the first direction is perpendicular to an extension direction of the to-be-treated isolation membrane (23); A processing module, used for spraying or scraping an insulating material on the portions of the isolation film (23) to be processed that extend beyond the mask plate (3) at both ends along the first direction, so as to obtain a first barrier region (232) on the first surface (23a), wherein the first barrier region (232) is used for blocking ions in the electrolyte; A removal module is used to remove the mask plate (3) to obtain the isolation membrane (23) of the electrode assembly, wherein the size (L231) of the first circulation area (231) along the first direction is less than or equal to the first size (L21), the first size (L21) is the size of the anode electrode piece isolated by the isolation membrane (23) along the first direction, the size (L23) of the isolation membrane (23) along the first direction is greater than the first size (L21) and greater than a second size (L22), and the second size (L22) is the size of the cathode electrode piece isolated by the isolation membrane (23) along the first direction.

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