Battery diaphragm and battery

Abstract

The utility model provides a battery diaphragm and a battery, and belongs to the technical field of battery manufacturing. The battery diaphragm comprises a base membrane and a coating. The coating is located on the surface of one side of the base film, the coating is provided with a first side and a second side which are opposite, a plurality of channels which are distributed at intervals and penetrate through the first side and the second side are formed in the coating, each channel is provided with a first section, a bent section and a second section which are sequentially communicated in the direction from the first side to the second side, and the bent section is bent towards the first side. According to the coating with the specific structure, the pole piece and the diaphragm can be fully infiltrated by electrolyte, so that a high polymer material in the coating is fully swelled and softened, the bonding force between the pole piece and the diaphragm is improved, and the electrical property of a corresponding battery is further improved.

Description

Technical Field

[0001] The present application relates to the technical field of battery manufacturing, and in particular to a battery separator and a battery. Background Art

[0002] In the prior art, for extra-large-sized batteries, the width dimension reaches 150-1550 mm, the length dimension reaches 100-1000 mm, and the thickness dimension reaches 8-26 mm. Since the dimensions of this type of battery are large in all dimensions, it is difficult to effectively transport the electrolyte to the internal area of ​​the diaphragm during injection, making it difficult for the electrode and the diaphragm to be fully infiltrated by the electrolyte. Accordingly, the polymer material in the diaphragm coating cannot fully swell and soften, resulting in a problem of weak adhesion between the electrode and the diaphragm in the battery, which in turn affects the electrical performance of the battery. Utility Model Content

[0003] The purpose of the present application is to provide a battery separator and a battery, which can make the electrode and the separator fully infiltrated with electrolyte, so that the polymer material in the coating can be fully swelled and softened, so as to improve the adhesion between the electrode and the separator, and then improve the electrical performance of the corresponding battery.

[0004] The embodiment of the present application is implemented as follows:

[0005] In a first aspect, an embodiment of the present application provides a battery separator, comprising a base film and a coating. The coating is located on one side of the base film, the coating has a first side and a second side opposite to each other, the coating has a plurality of channels distributed at intervals and penetrating the first side and the second side, and along the direction from the first side to the second side, the channel has a first section, a bending section, and a second section connected in sequence, and the bending section bends toward the first side.

[0006] In the above technical solution, a channel running through the first side and the second side is opened in the coating of the battery separator, and a bending section bent toward the first side is provided in the channel. When electrolyte is injected into the battery, a "siphon effect" can be formed with the help of a specific form of channel, so that the injected electrolyte is continuously transported to the inside of the separator, so that the battery separator and the electrode pieces in the corresponding area are fully infiltrated with the electrolyte, so that the polymer material in the coating is fully swollen and softened, so as to increase the bonding force between the electrode pieces and the separator, thereby improving the electrical performance of the corresponding battery.

[0007] In some optional embodiments, the coating further has a third side and a fourth side opposite to each other, and the width of the channel in the direction from the third side to the fourth side is defined as the inner width of the channel; along the direction from the second side to the first side, the inner width of the first section gradually increases.

[0008] In the above technical solution, the inner width of the first section is set to gradually increase along the direction from the second side to the first side. When the electrolyte is injected into the battery, more electrolyte can enter the channel, thereby improving the electrolyte transportation efficiency, so that the electrolyte can more thoroughly infiltrate the diaphragm and the electrode.

[0009] In some optional embodiments, the bending section has a first bending section and a second bending section connected in sequence, the first bending section is connected to the first section and connected to form a bending section bending toward the second side, and the second bending section is connected to the second section and connected to form a bending section bending toward the first side.

[0010] In the above technical solution, the bending section includes a first bending section connected to the first section and bent toward the second side, and a second bending section connected to the second section and bent toward the first side, that is, the bending section as a whole presents an "S shape". With the help of a specific form of the bending section, the electrolyte can be effectively transported to the inside of the diaphragm.

[0011] In some optional embodiments, each channel has two bending sections and two first sections, one end of each bending section away from the corresponding first section is connected and communicated with the second section, and the two bending sections are respectively located on both sides of the second section.

[0012] In the above technical solution, each channel has two first sections and two corresponding bending sections, and the two bending sections are connected to a second section at the same time and are located on both sides of the second section, that is, the bending section as a whole presents a "Y shape". With the help of a specific form of bending section, the electrolyte can be effectively transported to the inside of the diaphragm.

[0013] In some optional embodiments, the bending section has a third bending section, a fourth bending section and a fifth bending section that are connected in sequence, the third bending section is connected to the first section and connected to form a bending section that bends toward the second side, the fourth bending section bends in the direction between the first side and the second side, and the fifth bending section is connected to the second section and connected to form a bending section that bends toward the first side.

[0014] In the above technical solution, the bending section has three bending sections connected in sequence, wherein the third bending section is connected to the first section and bends toward the second side, the fourth bending section bends toward the direction between the first side and the second side, and the fifth bending section is connected to the second section and bends toward the first side, that is, the bending section as a whole presents an "Ω shape". With the help of a specific form of bending section, the electrolyte can be effectively transported to the inside of the diaphragm.

[0015] In some optional embodiments, each channel has two bending sections, and two ends of each bending section are respectively connected to and communicate with the first section and the second section, and the two bending sections are respectively located on both sides of the second section.

[0016] In the above technical solution, each channel has two bending sections, which are respectively connected to the first section and the second section and are located on both sides of the second section, that is, the bending section as a whole presents a "Φ shape". With the help of a specific form of bending section, the electrolyte can be effectively transported to the inside of the diaphragm.

[0017] In some optional embodiments, the extension direction of the first segment is from the first side to the second side, and / or the extension direction of the second segment is from the first side to the second side.

[0018] In the above technical solution, the first section and / or the second section is arranged to extend from the first side to the second side, that is, both sections are straight channels, which has the advantages of a relatively regular overall structure and convenient for transporting electrolyte.

[0019] In some optional embodiments, the inner widths of the bent section and the second section are 1 to 3 μm; and / or, along the thickness direction of the battery separator, the outer wall thickness of the channel is 1 to 3 μm.

[0020] In the above technical solution, the inner widths of the bending section and the second end are limited within a specific range, which can provide a more suitable flow rate for electrolyte transportation. At the same time, the inner widths of the bending section and the second section are made closer, so that the specifications of most of the channels are more consistent, thereby facilitating industrial manufacturing; at the same time, the outer wall thickness of the channel is limited within a specific range, so that the channel has a higher structural strength, thereby reducing the risk of channel collapse.

[0021] In some optional embodiments, the coating includes an inorganic coating and a glue layer that are stacked, the inorganic coating is located on the surface of the base film, the glue layer is located on the side of the inorganic coating away from the base film, and the channel is located between the inorganic coating and the glue layer.

[0022] In the above technical solution, the coating is set to a form of a combination of an inorganic coating and an adhesive layer, and the channel is set between the inorganic coating and the adhesive layer, which can effectively protect and fix the channel to improve the stability and service life of the channel; at the same time, the setting of the inorganic coating also helps to improve the safety performance of the battery.

[0023] In a second aspect, an embodiment of the present application provides a battery, comprising a shell and an electrode assembly, wherein one side of the shell has a liquid injection port, the electrode assembly comprises a positive electrode sheet, a negative electrode sheet, and a battery separator as provided in the embodiment of the first aspect and located between the positive electrode sheet and the negative electrode sheet, wherein the port of the first section faces the liquid injection port.

[0024] In the above technical scheme, the battery adopts the battery diaphragm provided in the first aspect embodiment, and the injection port on the outer shell corresponds to the port of the first section of the channel. When the electrolyte is injected into the battery, the injected electrolyte can be continuously transported to the inside of the diaphragm with the help of a specific form of channel, so that the battery diaphragm and the electrode pieces in the corresponding area are fully infiltrated with the electrolyte, so that the polymer material in the coating is fully swollen and softened, so as to increase the bonding force between the electrode pieces and the diaphragm, thereby improving the electrical performance of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 A schematic cross-sectional view of a first battery separator provided in an embodiment of the present application;

[0027] Figure 2 A schematic plan view of a first battery separator provided in an embodiment of the present application;

[0028] Figure 3 This is a schematic plan view of a second battery separator provided in an embodiment of the present application;

[0029] Figure 4 This is a schematic plan view of a third battery separator provided in an embodiment of the present application;

[0030] Figure 5 This is a schematic plan view of a fourth battery separator provided in an embodiment of the present application;

[0031] Figure 6 A schematic diagram of the roller structure of a glue coating roller in a channel construction mechanism provided in an embodiment of the present application;

[0032] Figure 7 for Figure 6 Schematic diagram of the roller surface structure at A in the middle.

[0033] Icon: 10-battery separator; 100-base film; 200-coating; 210-inorganic coating; 220-adhesive coating; 230-first side; 240-second side; 250-glue layer; 250a-channel; 251-first section; 252-bending section; 2521-first bending section; 2522-second bending section; 2523-third bending section; 2524-fourth bending section; 2525-fifth bending section; 253-second section; 260-third side; 270-fourth side; 30-glue coating roller; 31-roller body; 32-heating unit; 33-first end; 34-second end; 300-through groove. DETAILED DESCRIPTION

[0034] 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 and completely 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, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0035] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0036] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0037] In the description of this application, it should be noted that the terms "inside", "outside", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the application is usually placed when in use, which is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0038] In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" 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.

[0039] The battery separator and battery provided in this application are described in detail below.

[0040] First, see Figure 1 and Figure 2 ,in, Figure 2 The dotted line represents a dotted channel structure inside the coating 200. The embodiment of the present application provides a battery separator 10, including a base film 100 and a coating 200. The coating 200 is located on one side of the base film 100. The coating 200 has a first side 230 and a second side 240 that are opposite to each other. The coating 200 has a plurality of channels 250a that are spaced apart and penetrate the first side 230 and the second side 240. Along the direction from the first side 230 to the second side 240, the channel 250a has a first section 251, a bending section 252, and a second section 253 that are connected in sequence, and the bending section 252 is bent toward the first side 230.

[0041] In the present application, a channel 250a penetrating the first side 230 and the second side 240 is provided in the coating 200 of the battery separator 10, and a bent section 252 bent toward the first side 230 is provided in the channel 250a. When electrolyte is injected into the battery, a "siphon effect" can be formed with the help of a specific form of the channel 250a, so that the injected electrolyte is continuously transported to the interior of the separator, so that the battery separator 10 and the electrode sheets in the corresponding area are fully infiltrated with the electrolyte, so that the polymer material in the coating 200 is fully swollen and softened, so as to increase the bonding force between the electrode sheets and the separator, thereby improving the electrical performance of the corresponding battery.

[0042] It should be noted that the number of channels 250a or the distance between any two adjacent channels 250a is not limited and can be adjusted according to actual needs.

[0043] It should be noted that the battery type corresponding to the battery separator 10 is not limited, for example, it can be a laminated battery or a wound battery. Accordingly, the direction from the first side 230 to the second side 240 also needs to be adaptively adjusted.

[0044] As an example, the battery separator 10 corresponds to a wound battery, and accordingly, the direction from the first side 230 to the second side 240 is the width direction of the separator.

[0045] As an example, the battery separator 10 corresponds to a laminated battery, and accordingly, the direction from the first side 230 to the second side 240 can be either the width direction of the separator or the length direction of the separator.

[0046] In order to facilitate understanding of the technical solution of the present application, in the embodiments of the present application, the battery separator 10 is used for example in a wound battery, and accordingly, the direction from the first side 230 to the second side 240 is the width direction of the separator.

[0047] See also Figure 2 As an example, the coating 200 also has a third side 260 and a fourth side 270 relative to each other, and the width of the channel 250a in the direction from the third side 260 to the fourth side 270 (i.e., the length direction of the diaphragm) is defined as the inner width of the channel 250a; along the direction from the second side 240 to the first side 230, the inner width of the first section 251 gradually increases.

[0048] In this embodiment, the inner width of the first section 251 is set to gradually increase along the direction from the second side 240 to the first side 230. When the electrolyte is injected into the battery, more electrolyte can enter the channel 250a, thereby improving the electrolyte transportation efficiency, so that the electrolyte can more thoroughly infiltrate the diaphragm and the electrode.

[0049] It should be noted that the specific configuration of the bell mouth is not limited and can be adjusted according to actual needs.

[0050] It should be noted that the specific form of the bending section 252 is not limited, as long as it can form a "siphon effect".

[0051] See also Figure 2 As an example, the bending section 252 has a first bending section 2521 and a second bending section 2522 connected in sequence, the first bending section 2521 is connected to the first section 251 and connected to form a bending section bending toward the second side 240, and the second bending section 2522 is connected to the second section 253 and connected to form a bending section bending toward the first side 230.

[0052] In this embodiment, the bending section 252 includes a first bending section 2521 connected to the first section 251 and bent toward the second side 240, and a second bending section 2522 connected to the second section 253 and bent toward the first side 230, that is, the bending section 252 is "S-shaped" as a whole. With the help of the specific form of the bending section 252, the electrolyte can be effectively transported to the inside of the diaphragm.

[0053] See also Figure 3 , Figure 3The dotted line represents a dotted channel structure inside the coating 200. As an example, each channel 250a has two bending sections 252 and two first sections 251. The end of each bending section 252 away from the corresponding first section 251 is connected to and communicated with the second section 253. The two bending sections 252 are respectively located on both sides of the second section 253.

[0054] In this embodiment, each channel 250a has two first sections 251 and two corresponding bending sections 252, and the two bending sections 252 are simultaneously connected to a second section 253 and are located on both sides of the second section 253, that is, the bending section 252 is "Y-shaped" as a whole. With the help of the specific form of the bending section 252, the electrolyte can be effectively transported to the inside of the diaphragm.

[0055] See also Figure 4 , Figure 4 The dotted line represents a dotted channel structure inside the coating 200. As an example, the bending section 252 has a third bending section 2523, a fourth bending section 2524 and a fifth bending section 2525 which are connected in sequence. The third bending section 2523 is connected to the first section 251 and connected to form a bending section that bends toward the second side 240. The fourth bending section 2524 bends toward the direction between the first side 230 and the second side 240. The fifth bending section 2525 is connected to the second section 253 and connected to form a bending section that bends toward the first side 230.

[0056] In this embodiment, the bending section 252 has three bending sections connected in sequence, wherein the third bending section 2523 is connected to the first section 251 and bends toward the second side 240, the fourth bending section 2524 bends toward the direction between the first side 230 and the second side 240, and the fifth bending section 2525 is connected to the second section 253 and bends toward the first side 230, that is, the bending section 252 as a whole presents an "Ω shape", and with the help of the specific form of the bending section 252, the electrolyte can be effectively transported to the inside of the diaphragm.

[0057] See also Figure 5 , Figure 5 The dotted line represents a dotted channel structure inside the coating 200. As an example, each channel 250a has two bending sections 252, and the two ends of each bending section 252 are respectively connected and connected to the first section 251 and the second section 253, and the two bending sections 252 are respectively located on both sides of the second section 253.

[0058] In this embodiment, each channel 250a has two bending sections 252, which are respectively connected to the first section 251 and the second section 253 and are located on both sides of the second section 253, that is, the bending section 252 is "Φ-shaped" as a whole. With the help of the specific form of the bending section 252, the electrolyte can be effectively transported to the inside of the diaphragm.

[0059] It should be noted that the specific arrangement of the channel 250 a is not limited, as long as it can penetrate the first side 230 and the second side 240 of the diaphragm.

[0060] See also Figure 2 As an example, the extension direction of the first section 251 is from the first side 230 to the second side 240 , and / or the extension direction of the second section 253 is from the first side 230 to the second side 240 .

[0061] In this embodiment, the first section 251 and / or the second section 253 are arranged to extend from the first side 230 to the second side 240, that is, both sections are straight channels 250a, which has the advantages of a relatively regular overall structure and convenient transportation of electrolyte.

[0062] It can be understood that the inner width of the channel 250a is related to the transport efficiency of the electrolyte, and based on this, the inner width of the channel 250a can be limited.

[0063] As an example, the inner widths of the bending section 252 and the second section 253 are 1-3 μm, for example but not limited to any one of 1 μm, 2 μm and 3 μm, or a range between any two of the inner widths.

[0064] In this embodiment, the inner widths of the bending section 252 and the second end are limited to a specific range, which can provide a more suitable flow rate for electrolyte transportation. At the same time, the inner widths of the bending section 252 and the second section 253 are made closer, so that the specifications of most of the channel 250a are more consistent, thereby facilitating industrial manufacturing.

[0065] It can be understood that the outer wall thickness of the channel 250a is closely related to its structural stability, and based on this, the inner width of the channel 250a can be limited.

[0066] As an example, along the thickness direction of the battery separator 10, the outer wall thickness of the channel 250a (i.e., the wall thickness of the coating 200 facing away from the base film 100) is 1 to 3 μm, for example but not limited to an inner width of any point value of 1 μm, 2 μm and 3 μm or a range value between any two of them.

[0067] In this embodiment, the outer wall thickness of the channel 250a is limited to a specific range, so that the channel 250a has a higher structural strength, thereby reducing the risk of collapse of the channel 250a.

[0068] It is understandable that the form of the coating 200 is not limited and can be adjusted according to actual needs.

[0069] See also Figure 1As an example, the coating 200 includes a stacked inorganic coating 210 and a glue layer 250 , the inorganic coating 210 is located on the surface of the base film 100 , the glue layer 250 is located on the side of the inorganic coating 210 away from the base film 100 , and the channel 250a is located between the inorganic coating 210 and the glue layer 250 .

[0070] In this embodiment, the coating 200 is configured to be in the form of a combination of an inorganic coating 210 and an adhesive layer 250, and the channel 250a is disposed between the inorganic coating 210 and the adhesive layer 250, which can effectively protect and fix the channel 250a to improve the stability and service life of the channel 250a; at the same time, the setting of the inorganic coating 210 also helps to improve the safety performance of the battery.

[0071] See also Figure 1 As an example, the coating 200 further includes an adhesive coating 220 , and the adhesive coating 220 is located on a side of the adhesive layer 250 facing away from the base film 100 .

[0072] In this embodiment, the coating 200 is further provided with an adhesive coating 220 to help better protect and fix the channel 250a.

[0073] As an example, the thickness of the bonding coating 220 is 1-3 μm, for example but not limited to, any one of 1 μm, 2 μm and 3 μm, or a range between any two of the thicknesses.

[0074] In this embodiment, the thickness of the bonding coating 220 is limited within a specific range, which can better protect and fix the channel 250a, and at the same time, it is not easy to interfere with ion transport during battery operation.

[0075] It should be noted that any structure or unit not specifically limited or described in the battery separator 10 may be arranged according to conventional selection in the art.

[0076] As an example, the material of the inorganic coating 210 may be alumina or boehmite.

[0077] As an example, the material of the adhesive coating 220 may be PVDF, PEO, CMC, a derivative of PMMA or polyurethane.

[0078] In order to better understand the technical solution, the specific preparation process of the diaphragm is combined here for auxiliary explanation.

[0079] When the diaphragm manufacturing system is in operation, the base film is first pulled to the inorganic coating coating mechanism, and the inorganic coating slurry (such as ceramic liquid) in the coating tank is coated on the surface of the base film by the coating roller. Then, the base film coated with the inorganic coating slurry is pulled into the drying oven for drying.

[0080] In order to better understand the channel formation process, a structural schematic diagram of a rubber coating roller in the channel construction mechanism is used here for auxiliary explanation.

[0081] See also Figure 6 and Figure 7 ,in, Figure 6 The schematic diagram of the roller structure of the rubber coating roller is shown in FIG. Figure 7 Schematic diagram of the roller surface structure of the glue coating roller; in the channel construction mechanism, the glue coating roller 30 includes a roller body 31 and a heating unit 32. The roller body 31 has a first end 33 and a second end 34 that are relatively distributed along the axial direction of the roller body 31, and the surface of the roller body 31 is provided with a plurality of through grooves 300 that are distributed along the circumference of the roller body 31 and penetrate the first end 33 and the second end 34, and the shape of the through grooves 300 corresponds to the shape of the channel to be formed, so that the base film at the corresponding stage can form a channel of the corresponding shape after passing through the channel construction mechanism; the heating unit 32 is installed on the roller body 31 and is used to heat the surface of the roller body 31.

[0082] Specifically, the dried base film with the inorganic coating is then pulled to the channel construction mechanism, and as the glue coating roller rotates, any type of adhesive in the coating tank is brought into the "S-shaped", "Ω-shaped", "Y-shaped" or "Φ-shaped" through-groove area on the roller surface and the non-through-groove area on the roller surface. As the heating unit continues to heat the roller, the adhesive close to the roller body gradually dries and takes shape, and the adhesive away from the roller body becomes a semi-solid with a certain bonding ability. When the inorganic coating on the surface of the base film contacts the adhesive in the glue coating roller, the surface of the glue coating roller and the adhesive in the through-groove are brought out by the inorganic coating to form an adhesive layer with a channel, so that the channel is located between the inorganic coating and the adhesive layer.

[0083] Subsequently, the substrate with channels on its surface is pulled to the adhesive coating coating mechanism, and any type of adhesive in the coating tank is coated on the surface of the substrate with channels by a coating roller to form an adhesive coating, which further reinforces the channels.

[0084] In the second aspect, an embodiment of the present application provides a battery, including a shell and an electrode assembly, wherein one side of the shell has a liquid injection port, the electrode assembly includes a positive electrode sheet, a negative electrode sheet, and a battery separator 10 provided in the embodiment of the first aspect and located between the positive electrode sheet and the negative electrode sheet, wherein the port of the first section 251 faces the liquid injection port.

[0085] In the present application, the battery uses a battery separator 10 as provided in the first aspect embodiment, and the injection port on the outer shell corresponds to the port of the first section 251 of the channel 250a. When the electrolyte is injected into the battery, the injected electrolyte can be continuously transported to the interior of the separator with the help of a specific form of channel 250a, so that the battery separator 10 and the electrode in the corresponding area are fully infiltrated with the electrolyte, so that the polymer material in the coating 200 is fully swollen and softened, so as to increase the bonding force between the electrode and the separator, thereby improving the electrical performance of the battery.

[0086] It should be noted that any structure or unit in the battery that is not particularly limited or described may be arranged according to conventional selections in the art.

[0087] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A battery separator, characterized in that: include: Basement membrane; A coating, wherein the coating is located on one side surface of the base film, the coating has a first side and a second side opposite to each other, the coating has a plurality of spaced-apart channels penetrating the first side and the second side, and along the direction from the first side to the second side, the channel has a first section, a bending section, and a second section that are connected in sequence, and the bending section bends toward the first side.

2. The battery separator according to claim 1, characterized in that: The coating also has a third side and a fourth side opposite to each other, and the width of the channel in the direction from the third side to the fourth side is defined as the inner width of the channel; along the direction from the second side to the first side, the inner width of the first section gradually increases.

3. The battery separator according to claim 2, characterized in that: The bending section has a first bending section and a second bending section connected in sequence, the first bending section is connected to the first section and connected to form a bending section bending toward the second side, and the second bending section is connected to the second section and connected to form a bending section bending toward the first side.

4. The battery separator according to claim 3, characterized in that: Each of the channels has two bending sections and two first sections, one end of each bending section away from the corresponding first section is connected to and communicates with the second section, and the two bending sections are respectively located on both sides of the second section.

5. The battery separator according to claim 2, characterized in that: The bending section has a third bending section, a fourth bending section and a fifth bending section which are connected in sequence, the third bending section is connected to the first section and connected to form a bending section bending toward the second side, the fourth bending section is bent toward the direction between the first side and the second side, and the fifth bending section is connected to the second section and connected to form a bending section bending toward the first side.

6. The battery separator according to claim 5, characterized in that: Each of the channels has two bending sections, two ends of each bending section are respectively connected to and communicate with the first section and the second section, and the two bending sections are respectively located on both sides of the second section.

7. The battery separator according to any one of claims 1 to 6, characterized in that The first section extends in a direction from the first side to the second side, and / or the second section extends in a direction from the first side to the second side.

8. The battery separator according to any one of claims 2 to 6, characterized in that The inner widths of the bent section and the second section are 1 to 3 μm; and / or, along the thickness direction of the battery separator, the outer wall thickness of the channel is 1 to 3 μm.

9. The battery separator according to any one of claims 1 to 6, characterized in that The coating comprises an inorganic coating and an adhesive layer which are stacked and distributed. The inorganic coating is located on the surface of the base film, the adhesive layer is located on the side of the inorganic coating away from the base film, and the channel is located between the inorganic coating and the adhesive layer.

10. A battery, characterized in that: It comprises a shell and an electrode assembly, one side of the shell has a liquid injection port, the electrode assembly comprises a positive electrode sheet, a negative electrode sheet and a battery separator as described in any one of claims 1 to 9 located between the positive electrode sheet and the negative electrode sheet, and the port of the first section faces the liquid injection port.

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