Electrode sheet and dry preparation device and dry preparation method thereof

Abstract

The present invention belongs to the field of battery technology, and discloses an electrode sheet and dry preparation equipment and dry preparation method thereof. The dry preparation equipment of the electrode sheet comprises a conveying device, and a film forming device, an insulating feeding device and a composite rolling device sequentially arranged along the conveying direction of the current collector. The film forming device is used to extrude the conductive material into a self-supporting film and convey it to the current collector. The conveying device is used to convey the current collector and overlap the self-supporting film and the current collector to form a preliminary electrode sheet. The insulating feeding device is used to extrude the insulating material into an insulating layer and attach it to the empty foil area of ​​the preliminary electrode sheet to form an intermediate electrode sheet. The composite rolling device is used to roll the intermediate electrode sheet into an electrode sheet. The dry preparation equipment of the electrode sheet provided by the present invention effectively prevents the problem of burrs on the electrode sheet during the die-cutting process, thereby ensuring the safety of the battery cell.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to an electrode sheet and dry preparation equipment and a dry preparation method thereof. Background Art

[0002] The production of electrode sheets is the front-end link of battery cell production and has a decisive influence on the basic performance of battery cells. According to different processing technologies, the methods of preparing electrode sheets can be divided into two types: wet process and dry process. The wet process is a traditional method for preparing electrode sheets. It is to mix the active material, conductive agent and adhesive in a solvent in proportion to make a slurry, which is then extruded and coated on the surface of the current collector and rolled. The dry process is a new method for preparing electrode sheets. After the active material and conductive agent are dry-mixed evenly, a solid adhesive is added to form a self-supporting film under the fiberization action of the adhesive, and finally rolled and covered on the surface of the current collector. At present, the empty foil area of ​​the electrode sheet manufactured by the dry process, that is, the edges on both sides of the electrode sheet, may produce burrs after die-cutting, affecting the safety of the battery cell. Summary of the invention

[0003] The purpose of the present invention is to provide, in the first aspect, a dry-process preparation device for an electrode sheet, which can realize dry-process forming of a self-supporting film and an insulating layer, so that the insulating layer is distributed in the empty foil area of ​​the current collector, effectively preventing the dry-process electrode sheet from generating burrs during the die-cutting process, and ensuring the safety of the battery cell; in the second aspect, a dry-process preparation method for an electrode sheet, which can realize dry-process forming of a self-supporting film and an insulating layer, so that the insulating layer is distributed in the empty foil area of ​​the current collector, effectively preventing the dry-process electrode sheet from generating burrs during the die-cutting process, and ensuring the safety of the battery cell; in the third aspect, an electrode sheet prepared by the above-mentioned dry-process preparation device or the above-mentioned dry-process preparation method is provided.

[0004] To achieve this object, the present invention adopts the following technical solutions:

[0005] Provided is a dry preparation device for electrode sheets, comprising a conveying device, a film forming device, an insulating feeding device and a composite rolling device; wherein:

[0006] The conveying device is used to convey the current collector;

[0007] The film forming device, the insulating feeding device and the composite rolling device are sequentially arranged along the conveying direction of the current collector;

[0008] The film forming device is used to extrude the conductive material into a self-supporting film and convey it to the conveying device, and the conductive material does not contain a solvent;

[0009] The conveying device is used to stack the self-supporting film and the current collector together to form a preliminary pole piece;

[0010] The insulating material feeding device is used to extrude the insulating material into an insulating layer and attach it to the empty foil area of ​​the preliminary pole piece to form an intermediate pole piece, and the insulating material does not contain a solvent;

[0011] The composite rolling device is used for rolling the intermediate pole piece into an electrode sheet.

[0012] Preferably, the film forming device comprises a conductive feeding device, a first heating device, a film rolling device and a conveying roller group which are sequentially arranged along the conveying direction of the conductive material; wherein,

[0013] The conductive feeding device is used to extrude the conductive material into the self-supporting film;

[0014] The first heating device is used to heat the self-supporting film;

[0015] The film rolling device is used to roll the self-supporting film;

[0016] The conveying roller group is used to guide the self-supporting film to be conveyed to the conveying device;

[0017] Preferably, the structure of the insulating feeding device is the same as that of the conductive feeding device.

[0018] Preferably, the conductive feeding device comprises at least one first extrusion assembly, the first extrusion assembly comprises a first barrel, a first screw rod disposed in the first barrel, and a first driving member connected to the first screw rod, the first driving member being used to drive the screw rod to rotate and extrude the conductive material in the first barrel;

[0019] Preferably, the first barrel is provided with a feeding end and a discharging end in sequence from top to bottom along the vertical direction, and the discharging end of the first barrel is provided with a first discharging nozzle;

[0020] Preferably, the conductive feeding device further comprises a first roller assembly, the first roller assembly is arranged at the discharge end of the first barrel, and the first roller assembly is used to roll the conductive material to form the self-supporting film;

[0021] Preferably, the first roller assembly comprises a first upper roller and a first lower roller which are arranged opposite to each other, a first rolling gap is arranged between the first upper roller and the first lower roller, and the first discharge nozzle is arranged toward the first rolling gap;

[0022] Preferably, the conductive feeding device further comprises a first limiting assembly, a first forming groove is formed between the first limiting assembly and the first roller assembly, and the first forming groove is used to limit the forming width of the self-supporting film;

[0023] Preferably, the conductive feeding device further comprises a first transverse moving assembly, the first transverse moving assembly is connected to the first extruding assembly, and the first transverse moving assembly is used to drive the first extruding assembly to move along the width direction of the first rolling gap;

[0024] Preferably, the conductive feeding device further comprises a first vertical moving assembly, the first vertical moving assembly is connected to the first transverse moving assembly, and the first vertical moving assembly is used to drive the first extruding assembly to approach or move away from the first roller assembly;

[0025] Preferably, the film forming device comprises at least one of the conductive feeding devices.

[0026] Preferably, the film forming device further comprises a trimming device disposed between the film rolling device and the conveying roller set, wherein the trimming device is used for cutting the self-supporting film.

[0027] Preferably, the insulating feeding device comprises at least one second extruding assembly, the second extruding assembly comprises a second barrel, a second screw rod disposed in the second barrel, and a second driving member connected to the second screw rod, the second driving member being used to drive the screw rod to rotate and extrude the insulating material in the second barrel;

[0028] Preferably, the second barrel is provided with a feeding end and a discharging end in sequence from top to bottom in the vertical direction, and the discharging end of the second barrel is provided with a second discharging nozzle;

[0029] Preferably, the insulating feeding device further comprises a second roller assembly, the second roller assembly is arranged at the discharge end of the second barrel, and the second roller assembly is used for rolling the insulating material to form the insulating layer;

[0030] Preferably, the second roller assembly comprises a second upper roller and a second lower roller which are arranged opposite to each other, a second rolling gap is arranged between the second upper roller and the second lower roller, and the second discharge nozzle is arranged toward the second rolling gap;

[0031] Preferably, the insulating feeding device further comprises a second limiting assembly, a second forming groove is formed between the second limiting assembly and the second roller assembly, and the second forming groove is used to limit the forming width of the insulating layer;

[0032] Preferably, the insulating feeding device further comprises a second transverse moving assembly, the second transverse moving assembly is connected to the second extrusion assembly, and the second transverse moving assembly is used to drive the second extrusion assembly to move along the width direction of the second rolling gap;

[0033] Preferably, the insulating feeding device further comprises a second vertical moving assembly, the second vertical moving assembly is connected to the second transverse moving assembly, and the second vertical moving assembly is used to drive the second extruding assembly to approach or move away from the second roller assembly;

[0034] Preferably, the insulating feeding device is provided as at least one.

[0035] Preferably, the dry preparation equipment for the electrode sheet further comprises a forming heating device, which is arranged between the film forming device and the insulating feeding device, and is used to heat the preliminary electrode sheet;

[0036] Preferably, the dry preparation equipment for the electrode sheet further comprises a surface density detection device, which is arranged on a side of the composite rolling device facing the discharge end of the conveying device, and is used to detect the surface density of the electrode sheet; and / or,

[0037] The dry preparation equipment for the electrode sheet further comprises a thickness detection device, which is arranged on a side of the composite rolling device facing the discharge end of the conveying device, and is used to detect the thickness of the electrode sheet.

[0038] A dry preparation method for an electrode sheet is provided, which is applicable to the dry preparation device for an electrode sheet described in any one of the above items, and the dry preparation method comprises the following steps:

[0039] S100, extruding a conductive material into a self-supporting film and transferring the film to a current collector; the conductive material does not contain a solvent;

[0040] S200, stacking the self-supporting film and the current collector together to form a preliminary pole piece;

[0041] S300, extruding an insulating material into an insulating layer and attaching the insulating material to the empty foil area of ​​the preliminary electrode to form an intermediate electrode; the insulating material does not contain a solvent;

[0042] S400, rolling the intermediate electrode sheet into an electrode sheet.

[0043] Preferably, the steps include:

[0044] Step S100 specifically includes: controlling a film forming device to extrude the conductive material into the self-supporting film and transferring the film to the current collector;

[0045] Preferably, the conductive material is obtained by dry-mixing the active material and the conductive agent, stirring them uniformly, and then adding a solid binder to perform a fiberization treatment;

[0046] Preferably, the active material is a positive electrode active material or a negative electrode active material;

[0047] Preferably, the solid binder includes at least one of polytetrafluoroethylene, polyvinylidene fluoride, polyethylene oxide, and polyacrylate;

[0048] Preferably, the temperature of the fiberization treatment is 40°C-200°C;

[0049] Step S200 specifically includes: controlling the conveying device to stack the self-supporting film and the current collector together to form the preliminary electrode sheet;

[0050] Preferably, controlling the laminating roller to laminate the self-supporting film and the current collector together to form the preliminary pole piece;

[0051] Step S300 specifically includes: controlling the insulating material feeding device to extrude the insulating material into the insulating layer and conveying it to the empty foil area of ​​the preliminary electrode piece to form the intermediate electrode piece;

[0052] Preferably, the insulating material is obtained by dry-mixing ceramic powder and a solid binder, stirring them uniformly, and then performing a fiberization treatment;

[0053] Preferably, the ceramic powder includes at least one of alumina, boehmite, and silicon oxide;

[0054] Preferably, the solid binder includes at least one of polytetrafluoroethylene, polyvinylidene fluoride, polyethylene oxide, and polyacrylate;

[0055] Preferably, in terms of percentage, the mass fraction of the solid binder is 5%-15%, and the mass fraction of the ceramic powder is 85%-95%;

[0056] Preferably, the temperature of the fiberization treatment is 40°C-200°C;

[0057] Step S400 specifically includes: controlling the composite rolling device to roll-form the intermediate electrode sheet into the electrode sheet;

[0058] Preferably, after the electrode sheet is roll-formed, the surface density and / or thickness of the electrode sheet is also detected;

[0059] Preferably, the surface density detection device is controlled to detect the surface density of the electrode sheet and / or the thickness detection device is controlled to detect the thickness of the electrode sheet.

[0060] Preferably, step S100 specifically includes the following steps:

[0061] S110, extruding the conductive material into the self-supporting film;

[0062] Preferably, controlling a conductive feeding device to extrude the conductive material into the self-supporting film;

[0063] Preferably, during the forming process, the self-supporting film is also rolled;

[0064] Preferably, the first roller assembly is further controlled to roll the self-supporting film;

[0065] Preferably, the rolling method is vertical rolling;

[0066] Preferably, the rolling method is hot pressing;

[0067] Preferably, the rolling temperature is 40°C-200°C;

[0068] S120, heating the self-supporting film;

[0069] Preferably, controlling the first heating device to heat the self-supporting film;

[0070] Preferably, the heating method is electromagnetic heating, infrared heating or resistance wire heating;

[0071] Preferably, the heating temperature is 100°C-300°C;

[0072] S130, rolling the self-supporting film;

[0073] Preferably, controlling the film rolling device to roll the self-supporting film;

[0074] Preferably, the rolling method is multi-stage rolling; preferably, the film rolling device comprises a multi-stage first pair of rollers;

[0075] Preferably, along the conveying direction of the current collector, the rolling gap of the first pair of rollers at each stage decreases, and the rolling pressure of the first pair of rollers at each stage increases;

[0076] Preferably, the rolling method is hot pressing;

[0077] Preferably, the rolling temperature is 40°C-200°C;

[0078] Preferably, after rolling the self-supporting film, the surface density and / or thickness of the self-supporting film is also detected;

[0079] Preferably, the surface density detection device is controlled to detect the surface density of the self-supporting film and / or the thickness detection device is controlled to detect the thickness of the self-supporting film;

[0080] S140, transferring the self-supporting film onto the current collector;

[0081] Preferably, the conveying roller group is controlled to guide the self-supporting film to be conveyed onto the current collector;

[0082] Preferably, before the self-supporting film is transported, the self-supporting film is also cut;

[0083] Preferably, controlling the trimming device to trim the self-supporting film;

[0084] Preferably, the edge cutting method is laser cutting, tungsten steel knife cutting or ceramic knife cutting.

[0085] Provided is an electrode sheet, which is prepared using any of the above-mentioned dry preparation equipment for electrode sheets or prepared by any of the above-mentioned dry preparation methods for electrode sheets.

[0086] Beneficial effects:

[0087] The dry preparation equipment of the electrode sheet provided by the present invention, in the process of the conveying device conveying the current collector, the conductive material is extruded into a self-supporting film by the film forming device and conveyed to the current collector to form a preliminary electrode sheet, the insulating feeding device extrudes the insulating material into an insulating layer and conveys it to the empty foil area of ​​the preliminary electrode sheet to form an intermediate electrode sheet; the composite rolling device rolls the intermediate electrode sheet into an electrode sheet, and the insulating layer is distributed in the empty foil area of ​​the current collector, which effectively prevents the dry electrode sheet from generating burrs in the die-cutting process, thereby ensuring the safety of the battery cell. In addition, the preliminary electrode sheet is first made, so that the self-supporting film has been basically finalized, and then it is compositely rolled with the insulating layer and the current collector, so that the self-supporting film will not have a large deformation, and the self-supporting film can be prevented from extending and fusing with the insulating layer.

[0088] The dry preparation method of the electrode sheet provided by the present invention can realize the dry forming of the self-supporting film and the insulating layer, so that the insulating layer is distributed in the empty foil area of ​​the current collector, effectively preventing the dry electrode sheet from generating burrs during the die-cutting process, and ensuring the safety of the battery cell.

[0089] The electrode sheet provided by the present invention can prevent the problem of burrs being generated in the die-cutting process of the dry-process electrode sheet, thereby effectively ensuring the safety of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0090] Figure 1 It is a schematic diagram of the production structure of the dry method preparation equipment of the electrode sheet provided by the present invention;

[0091] Figure 2 This is a schematic diagram of the structure of a one-inlet and two-outlet electrode sheet provided by the present invention;

[0092] Figure 3 It is a partial structural schematic diagram of the film forming device provided by the present invention;

[0093] Figure 4 is a partial structural schematic diagram of the first limit assembly provided by the present invention;

[0094] Figure 5This is a schematic diagram of the structure of the one-input and four-output electrode sheet provided by the present invention;

[0095] Figure 6 It is a schematic diagram of the process of preparing the electrode sheet provided by the present invention.

[0096] In the figure:

[0097] 10. electrode sheet; 11. current collector; 12. self-supporting film; 13. insulating layer;

[0098] 100, conveying device; 110, unwinding roller; 120, winding roller; 130, overlapping roller; 140, third guide roller;

[0099] 200, film forming device; 210, conductive feeding device; 211, first extrusion assembly; 2111, first barrel; 21111, first discharge nozzle; 2112, first screw rod; 2113, first driving member; 212, first roller assembly; 213, first limit assembly; 2131, first baffle; 2132, first longitudinal screw rod; 214, first transverse assembly; 2141, first transverse screw rod; 2142, first transverse support frame; 215, first vertical assembly; 2151, first vertical screw rod; 2152, first vertical motor; 220, first heating device; 230, film rolling device; 240, conveying roller group; 241, first guide roller; 242, second guide roller; 250, trimming device;

[0100] 300, insulating feeding device; 310, second roller assembly;

[0101] 400, composite roller pressing device;

[0102] 510, first roller; 520, second roller; 530, third roller; 540, fourth roller; 550, fifth roller;

[0103] 600, forming heating device;

[0104] 700. Surface density detection device;

[0105] 800. Thickness detection device. DETAILED DESCRIPTION

[0106] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0107] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" 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 mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0108] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0109] In the description of this embodiment, the terms "upper", "lower", "right", etc., directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0110] Embodiment 1

[0111] Reference Figure 1 and Figure 2 As shown, this embodiment provides a dry preparation device for an electrode sheet, including a conveying device 100 for conveying a current collector 11, and a film forming device 200, an insulating feeding device 300 and a composite rolling device 400 arranged in sequence along the conveying direction of the current collector 11.

[0112] Specifically, the film forming device 200 is used to extrude the conductive material into a self-supporting film 12 and convey it to the conveying device 100; the conveying device 100 is used to stack the self-supporting film 12 and the current collector 11 together to form a preliminary pole piece; the insulating feeding device 300 is used to extrude the insulating material into an insulating layer 13 and attach it to the empty foil area of ​​the preliminary pole piece to form an intermediate pole piece; the composite rolling device 400 is used to roll the intermediate pole piece into the electrode sheet 10. Among them, the conductive material and the insulating material do not contain solvents.

[0113] The dry preparation equipment of the electrode sheet provided in this embodiment, in the process of the conveying device 100 conveying the current collector 11, the conductive material is extruded into a self-supporting film 12 by the film forming device 200 and conveyed to the current collector 11 to form a preliminary electrode sheet, the insulating feeding device 300 extrudes the insulating material into an insulating layer 13 and conveys it to the empty foil area of ​​the preliminary electrode sheet to form an intermediate electrode sheet; the composite rolling device 400 rolls the intermediate electrode sheet into an electrode sheet 10, and the insulating layer 13 is distributed in the empty foil area of ​​the current collector 11, which effectively prevents the dry electrode sheet 10 from generating burrs in the die-cutting process, thereby ensuring the safety of the battery cell. In addition, the preliminary electrode sheet is first made, so that the self-supporting film 12 has been basically finalized, and then it is compositely rolled with the insulating layer 13 and the current collector 11, so that the self-supporting film 12 will not have a large deformation, and the self-supporting film 12 can be prevented from extending and fusing with the insulating layer 13.

[0114] It is worth mentioning that the insulating layer 13 can be distributed in the entire empty foil area of ​​the preliminary pole piece, or in part of the empty foil area of ​​the preliminary pole piece. In this embodiment, two insulating layers 13 are distributed on the two side edges of the self-supporting film 12 of the preliminary pole piece.

[0115] In this embodiment, continue to refer to Figure 1 As shown, the conveying device 100 includes a unwinding roller 110 and a winding roller 120. The unwinding roller 110 is located at the loading end of the conveying device 100, and is used to place the rolled current collector 11. For example, the current collector 11 can be a foil roll. The winding roller 120 is located at the discharging end of the conveying device 100, and is used to wind up the electrode sheet 10.

[0116] In this embodiment, refer to Figure 1 , Figure 3 and Figure 4 As shown, two film forming devices 200 are provided and are respectively located at the upper and lower sides of the conveying device 100 .

[0117] Specifically, the film forming device 200 includes a conductive feeding device 210, a first heating device 220, a film rolling device 230 and a conveying roller group 240 which are sequentially arranged along the conveying direction of the conductive material. The conductive feeding device 210 is used to extrude the conductive material into a self-supporting film 12, the first heating device 220 is used to heat the self-supporting film 12, the film rolling device 230 is used to roll the self-supporting film 12, and the conveying roller group 240 is used to guide the self-supporting film 12 onto the conveying device 100. Illustratively, first, the self-supporting film 12 is extruded and formed by the conductive feeding device 210, and the self-supporting film 12 is initially formed; then, the initially formed self-supporting film 12 is heated by the first heating device 220 to make the self-supporting film 12 have better plasticity; finally, the self-supporting film 12 is rolled by the film rolling device 230 to achieve the desired thickness and compaction density, thereby effectively ensuring the surface quality of the self-supporting film 12. At this time, the self-supporting film 12 has been basically shaped, and when the composite rolling device 400 is used for rolling forming, the self-supporting film 12 will not have a large deformation, thereby effectively preventing the self-supporting film 12 from stretching and fusing with the insulating layer 13.

[0118] Exemplarily, the conductive material is a mixture obtained by dry-mixing the positive electrode main material and the conductive agent, and then adding a binder for fiberization. The binder can be one or more combinations of polytetrafluoroethylene, polyvinylidene fluoride, polyethylene oxide, and polyacrylate, preferably polytetrafluoroethylene.

[0119] Specifically, the conductive feeding device 210 includes at least one first extrusion assembly 211, the first extrusion assembly 211 includes a first barrel 2111, a first screw rod 2112 disposed in the first barrel 2111, and a first driving member 2113 connected to the first screw rod 2112, and the first driving member 2113 is used to drive the screw rod to rotate and extrude the conductive material in the first barrel 2111. Among them, the first barrel 2111 includes a feed end and a discharge end. In this embodiment, the first screw rod 2112 is driven to rotate by the first driving member 2113, and the spiral of the first screw rod 2112 can evenly squeeze the conductive material from the feed end of the first barrel 2111 to the discharge end. Under the action of the centrifugal force and gravity of the first screw rod 2112, high-viscosity materials can be effectively transported, and the finished product yield of the self-supporting film 12 is effectively guaranteed.

[0120] Exemplarily, the first barrel 2111 is provided with a feed end and a discharge end in sequence from top to bottom in the vertical direction, and the discharge end of the first barrel 2111 is provided with a first discharge nozzle 21111, and the first barrel 2111 discharges materials in the vertical direction, and the discharge shape of the conductive material is limited by the first discharge nozzle 21111, so as to effectively ensure the uniformity of the discharge. The feed width can be controlled by controlling the width of the first discharge nozzle 21111, and the feed thickness can be controlled by controlling the length of the first discharge nozzle 21111, so as to match the self-supporting films 12 of different widths and thicknesses, and the control of the film width and thickness is intervened in advance, which can effectively improve the processing efficiency and quality of the self-supporting film 12.

[0121] Exemplarily, the first driving member 2113 may be a motor.

[0122] Specifically, the conductive feeding device 210 further includes a first roller assembly 212, which is disposed at the discharge end of the first barrel 2111, and is used to roll the conductive material to form a self-supporting film 12. In this embodiment, the conductive material extruded from the discharge end is rolled into the self-supporting film 12 by the first roller assembly 212, so that the thickness and compaction density of the self-supporting film 12 are initially formed, with a simple structure and stable performance.

[0123] Exemplarily, the first roller assembly 212 includes a first upper roller and a first lower roller that are arranged opposite to each other, a first rolling gap is arranged between the first upper roller and the first lower roller, and the first discharge nozzle 21111 is arranged toward the first rolling gap. In this embodiment, the conductive material squeezed out of the first discharge nozzle 21111 is rolled into a self-supporting film 12 during the process of passing through the first rolling gap, which has a simple structure and stable performance.

[0124] Exemplarily, the first upper roller and the first lower roller can move closer to or farther from each other to adjust the width of the first rolling gap. Figure 3 The X direction of the first rolling gap is close to or away from each other, and the width of the first rolling gap can be understood as the width of the first rolling gap along the Figure 3 The mechanism for controlling the position adjustment of the first upper roller and the first lower roller is a prior art and is not the focus of this application, so it will not be described in detail.

[0125] Specifically, the conductive feeding device 210 further includes a first limiting assembly 213, a first forming groove is formed between the first limiting assembly 213 and the first roller assembly 212, and the first forming groove is used to limit the forming width of the self-supporting film 12. The forming width of the self-supporting film 12 can be understood as the width of the self-supporting film 12 along the Figure 3In this embodiment, the conductive material extruded from the first discharge nozzle 21111 passes through the first molding groove, and the molding width of the self-supporting film 12 is limited by the first molding groove, so that the width of the self-supporting film 12 is initially formed, effectively ensuring the molding accuracy and quality of the self-supporting film 12, and having a simple structure and stable performance.

[0126] Exemplarily, the first limiting assembly 213 includes at least two first baffles 2131, such as Figure 4 As shown, the two first baffles 2131 can move closer to or farther from each other to adjust the length of the first forming groove. Figure 3 The Y direction in the figure is close to or far away from each other. The length of the first forming groove can be understood as the length of the first forming groove along the Figure 3 Every two first baffles 2131 limit the forming width of a self-supporting film 12 , and the number of first limiting components 213 or the number of first baffles 2131 is selected according to the number of self-supporting films 12 required.

[0127] Exemplarily, the first limit assembly 213 also includes a first longitudinal movement drive member, which includes a first longitudinal movement motor and a first longitudinal movement screw 2132. The two first baffles 2131 are each penetrated by two first longitudinal movement screws 2132; and the two first longitudinal movement screws 2132 are both threadedly connected to the two first baffles 2131, and the threaded holes of the two first baffles 2131 have opposite threaded directions; or each first baffle 2131 is provided with a first longitudinal movement nut threadedly connected to each first longitudinal movement screw 2132, and the threaded holes of the two first longitudinal movement nuts have opposite threaded directions, and the first longitudinal movement screws 2132 are both connected to the first longitudinal movement motor, and the two first longitudinal movement screws 2132 are driven to rotate by the first longitudinal movement motor, thereby driving the two first baffles 2131 to move closer to or farther from each other for easy adjustment. The axial direction of the first longitudinal movement screw 2132 can be understood as Figure 3 in the Y direction.

[0128] Exemplarily, the edge of the first baffle 2131 may fit with the peripheral side surfaces of the first upper roller and the first lower roller.

[0129] For example, the first baffle 2131 may be chrome plated or ceramic plated or carbide plated.

[0130] In this embodiment, the width of the first rolling gap and the length of the first forming groove are adjustable so as to adapt to self-supporting films 12 of different thicknesses and different film widths. The control of the film width and thickness is intervened before the film rolling device 230, which can effectively improve the forming efficiency and quality of the self-supporting film 12.

[0131] In this embodiment, the width and thickness of the feed are controlled by the first extrusion component 211, the thickness and compaction density of the self-supporting film 12 are controlled by the first roller component 212, and the width of the self-supporting film 12 is limited by the first limiting component 213, so that the width, thickness and compaction density of the self-supporting film 12 are initially formed.

[0132] Specifically, the conductive feeding device 210 also includes a first transverse movement component 214, which is connected to the first extrusion component 211. The first transverse movement component 214 is used to drive the first extrusion component 211 to move along the width direction of the first rolling gap. The position of the first extrusion component 211 is adjusted by the first transverse movement component 214 so that the conductive material falls into the first rolling gap in the center, effectively preventing the conductive material from piling up in the first rolling gap and making the conductive material rolled evenly, effectively ensuring the film quality.

[0133] Exemplarily, the first transverse movement assembly 214 includes a first transverse movement screw 2141, a first transverse movement support frame 2142 and a first transverse movement motor (not shown). The first transverse movement screw 2141 is provided with at least one, for example, two, first transverse movement support frame 2142 is connected to the first extrusion assembly 211, the first transverse movement screw 2141 is threadedly connected to the first transverse movement support frame 2142, or the first transverse movement screw 2141 is threadedly connected to the first transverse movement nut provided on the first transverse movement support frame 2142, and the first transverse movement screw 2141 is connected to the first transverse movement motor. The first transverse movement motor drives the first transverse movement screw 2141 to rotate so that the first transverse movement support frame 2142 moves along the axial direction of the first transverse movement screw 2141, thereby realizing the movement of the first extrusion assembly 211 along the width direction of the first rolling gap, which is convenient for adjustment. Among them, the axial direction of the first transverse movement screw 2141 and the width direction of the first rolling gap can be understood as Figure 3 The X direction in .

[0134] Specifically, the conductive feeding device 210 also includes a first vertical moving assembly 215, which is connected to the first transverse moving assembly 214, and is used to drive the first extrusion assembly 211 to move closer to or away from the first roller assembly 212. In this embodiment, the vertical position of the first extrusion assembly 211 is adjusted by the first vertical moving assembly 215, so that the distance at which the conductive material falls from the first discharge nozzle 21111 of the first barrel 2111 into the first forming groove is moderate, thereby effectively preventing the conductive material from being broken or piled up between the first discharge nozzle 21111 of the first barrel 2111 and the first rolling gap and / or the first forming groove. Among them, the first vertical moving assembly 215 is used to drive the first extrusion assembly 211 to move in the vertical direction. Among them, the vertical direction can be understood as Figure 3 The Z direction in .

[0135] Exemplarily, the first vertical movement assembly 215 includes a first vertical movement screw rod 2151, a first vertical movement support frame (not shown) and a first vertical movement motor 2152. The first vertical movement screw rod 2151 is provided with at least one, for example, two. The first vertical movement support frame is connected to the first transverse movement assembly 214. The first vertical movement screw rod 2151 is threadedly connected to the first vertical movement support frame, or the first vertical movement screw rod 2151 is threadedly connected to the first vertical movement nut provided on the first vertical movement support frame. The first vertical movement support frame is rotatably connected to the first transverse movement screw rod 2141. The first vertical movement screw rod 2151 is connected to the first vertical movement motor 2152. The first vertical movement screw rod 2151 is driven to rotate by the first vertical movement motor 2152 to make the first vertical movement support frame and the first transverse movement screw rod 2141 move along the axial direction of the first vertical movement screw rod 2151. The first vertical movement screw rod 2151 is extended in the vertical direction, thereby realizing the movement of the first extrusion assembly 211 in the vertical direction for easy adjustment. Exemplarily, the first vertical motors 2152 can be connected to the first vertical screw rods 2151 in a one-to-one correspondence, and each first vertical motor 2152 drives the corresponding first vertical screw rod 2151 to rotate; or all the first vertical screw rods 2151 can be connected by one first vertical motor 2152, and the first vertical screw rods 2151 can be driven to rotate by one first vertical motor 2152.

[0136] In this embodiment, the vertical position of the first extrusion component 211 is adjusted by the first vertical movement component 215, so that the conductive material falls from the first discharge nozzle 21111 of the first barrel 2111 to the first forming groove at a moderate distance, effectively preventing the conductive material from being broken or piled up between the first discharge nozzle 21111 of the first barrel 2111 and the first rolling gap and / or the first forming groove; the position of the first extrusion component 211 is adjusted by the first transverse movement component 214, so that the conductive material falls into the first rolling gap in the center, effectively preventing the conductive material from being piled up in the first rolling gap and making the conductive material rolled evenly, thereby effectively ensuring the film formation quality.

[0137] Specifically, the heating method of the first heating device 220 includes but is not limited to electromagnetic heating, infrared heating, and resistance wire heating, and it is a prior art and will not be elaborated in detail in this application.

[0138] Specifically, the film rolling device 230 rolls the self-supporting film 12 in a multi-stage continuous rolling manner, such as 1-8 stages of continuous rolling. Specifically, the film rolling device 230 includes a multi-stage first pair of rollers, and the rolling gap of each stage of the first pair of rollers decreases along the conveying direction of the self-supporting film 12, and the rolling pressure of each stage of the first pair of rollers increases, so that the self-supporting film 12 is gradually thinned and densified, so that the self-supporting film 12 reaches the required thickness and compaction density.

[0139] Further, the roller diameters of the first pair of rollers at each level can be adjusted independently. For example, the diameters of the first pair of rollers at different levels along the conveying direction of the self-supporting film 12 are successively reduced or the same to ensure the surface quality of the self-supporting film 12. For example, the roller diameters of the first pair of rollers can be 10mm-500mm. Further, the rotation speed of the first pair of rollers at each level and the pressure on the self-supporting film 12 can be individually regulated. In this embodiment, the film rolling device 230 can roll the self-supporting film 12 in a hot rolling manner to further improve the plasticity of the self-supporting film 12, and the temperature can be 40°C-200°C. Of course, the film rolling device 230 can also roll the self-supporting film 12 in a single-stage rolling manner. In addition, the film rolling device 230 is a prior art, and its specific structure will not be described in detail in this application.

[0140] For example, the self-supporting film 12 may be wound around the first pair of rollers in an S-shaped winding manner or a linear winding manner, which is not limited in the present application.

[0141] In this embodiment, the initially formed self-supporting film 12 is heated by the first heating device 220 to make the self-supporting film 12 have better plasticity; then the self-supporting film 12 is gradually thinned and densified through multi-stage continuous rolling of the film rolling device 230; this adjustment method is more gentle on the thickness and compaction density of the self-supporting film 12, avoiding the self-supporting film 12 from being deformed, uneven, damaged or broken due to excessive thickness difference and pressure difference, thereby improving the rolling effect and the mechanical strength and tensile strength of the self-supporting film 12.

[0142] In this embodiment, refer to Figure 1 As shown, a first roller 510 is arranged between the first roller assembly 212 and the first heating device 220. The self-supporting film 12 is transferred to the first heating device 220 via the first roller 510 to ensure that the self-supporting film 12 on the film rolling device 230 remains straight, that is, to ensure the flatness of the self-supporting film 12 and effectively ensure the rolling quality.

[0143] Exemplarily, at least one first roller 510 is provided. For example, if two first rollers 510 are provided, the two first rollers 510 are respectively located on both sides of the self-supporting film 12 and are spaced apart along the conveying direction of the self-supporting film 12 .

[0144] In this embodiment, refer to Figure 1As shown, the conveying roller set 240 includes a plurality of guide rollers, through which the conveying direction of the self-supporting film 12 is guided. In this embodiment, the guide rollers can achieve a tensioning effect so that the self-supporting film 12 and the current collector 11 are well attached. For example, the conveying roller set 240 includes at least one first guide roller 241 and at least one second guide roller 242 sequentially arranged along the conveying direction of the self-supporting film 12, wherein the first guide roller 241 and the self-supporting film 12 on the first pair of rollers maintain a straight line, effectively ensuring the rolling quality of the film rolling device 230 on the self-supporting film 12, and the second guide roller 242 guides the self-supporting film 12 to the current collector 11.

[0145] In this embodiment, refer to Figure 1 As shown, the conveying device 100 further includes a stacking roller 130 disposed between the unwinding roller 110 and the winding roller 120 , and the stacking roller 130 stacks the self-supporting film 12 and the current collector 11 together to form a preliminary electrode sheet. The second guide roller 242 guides the self-supporting film 12 to the stacking roller 130 .

[0146] Furthermore, the conveying device 100 further includes a third guide roller 140 and a second roller 520, and the superimposed roller 130, the third guide roller 140 and the second roller 520 are sequentially arranged along the conveying direction of the current collector 11. Among them, the superimposed roller 130, the third guide roller 140 and the second roller 520 together form a tensioning structure, which effectively ensures that the self-supporting film 12 and the current collector 11 are well attached. Exemplarily, the superimposed roller 130, the third guide roller 140 and the second roller 520 are not in the same plane, and the preliminary pole piece at the tensioning structure is V-shaped.

[0147] In this embodiment, refer to Figure 1 As shown, the film forming device 200 further includes a trimming device 250 disposed between the film rolling device 230 and the conveying roller set 240 . The trimming device 250 is used to trim the self-supporting film 12 so that the width dimension of the self-supporting film 12 meets the requirements.

[0148] For example, the trimming device 250 can cut the self-supporting film 12 by laser cutting, carbide tungsten steel knife cutting, ceramic slitting knife cutting, or the like.

[0149] Exemplarily, the film forming device 200 is provided as at least one, and the film forming device 200 includes at least one conductive feeding device 210. The conductive feeding device 210 includes at least one first extrusion component 211, and each first extrusion component 211 is respectively provided with a first limiting component 213.

[0150] In the related art, Chinese Patent 202220974844.6 discloses an electrode film forming device and a dry electrode manufacturing equipment, wherein the electrode film forming device includes a first roller, a second roller and a hopper, the first roller is opposite to the second roller, and a rolling gap is defined between the first roller and the second roller; the interior of the hopper is provided with an insulating material cavity and a conductive material cavity, the outer wall of the hopper is provided with a first discharge port and a second discharge port, and the first discharge port is provided on both sides of the second discharge port, the first discharge port is connected to the insulating material cavity, and the second discharge port is connected to the conductive material cavity, the insulating material cavity is used to transport the insulating powder to the rolling gap through the first discharge port to form an insulating layer, and the conductive material cavity is used to transport the conductive powder to the rolling gap through the second discharge port to form a conductive film, the forming of the insulating layer and the conductive film can be carried out simultaneously to form an integrated electrode film, and there is no need to perform the glue coating operation at the pole ear in the subsequent steps, which can simplify the equipment and process flow, improve production efficiency, and reduce production costs. However, the forming of the insulating layer and the conductive film is only pre-forming, and their width, thickness and compaction density are not yet stable. During the composite rolling process, under the action of the rolling pressure, their width, thickness and compaction density may change significantly, causing the self-supporting film to extend laterally and dissolve into the insulating layer, affecting the performance of the battery cell.

[0151] In this embodiment, the self-supporting film 12 is first formed by the conductive feeding device 210, and then the width, thickness and compaction density of the self-supporting film 12 are basically finalized through the first heating device 220, the film rolling device 230, the trimming device 250, etc., and then it is overlapped with the current collector 11 to form a preliminary electrode sheet to be supported by the current collector 11, and then the insulating layer 13 is attached, and then they are compositely rolled together. During the rolling process, the self-supporting film 12 will not have a large deformation, thereby avoiding the occurrence of the situation where the width of the self-supporting film 12 is extended and merged with the insulating layer 13.

[0152] In this embodiment, the insulating feeding device 300 includes at least one second extrusion assembly (not shown). Specifically, the second extrusion assembly includes a second barrel, a second screw rod disposed in the second barrel, and a second driving member connected to the second screw rod, and the second driving member is used to drive the screw rod to rotate and extrude the insulating material in the second barrel. In this embodiment, the second screw rod is driven to rotate by the second driving member, and the second barrel includes a feed end and a discharge end. The spiral energy of the second screw rod can evenly extrude the insulating material from the feed end of the second barrel to the discharge end, and the insulating material extruded from the discharge end is formed into an insulating layer 13.

[0153] Exemplarily, the second extrusion assembly is adjustable along the width direction of the current collector 11 so that the insulating layer 13 can be precisely covered on the edge of the corresponding side of the self-supporting film 12 , and the applicability is improved, and it can be applicable to the production of electrode sheets 10 of various specifications.

[0154] Exemplarily, the second barrel is provided with a feed end and a discharge end in sequence from top to bottom in the vertical direction, and the discharge end of the second barrel is provided with a second discharge nozzle. The structure of the second barrel is the same as that of the first barrel 2111, and this application will not go into details.

[0155] Exemplarily, the second driving member may be a motor.

[0156] Specifically, the insulating feeding device 300 further includes a second roller assembly 310 , which is disposed at the discharge end of the second barrel, and is used for rolling the insulating material to form the insulating layer 13 .

[0157] Exemplarily, the second roller assembly 310 includes a second upper roller and a second lower roller that are arranged opposite to each other, a second rolling gap is arranged between the second upper roller and the second lower roller, and the second discharge nozzle is arranged toward the second rolling gap. The structure of the second roller assembly 310 is the same as that of the first roller assembly 212, and the width of the second rolling gap can also be adjusted, which will not be described in detail in this application.

[0158] Specifically, the insulating feeding device 300 further includes a second limiting assembly (not shown) corresponding to the second extruding assembly, and a second forming groove is formed between the second limiting assembly and the second roller assembly 310, and the second forming groove is used to limit the forming width of the insulating layer 13. Among them, the structure of the second limiting assembly is the same as that of the first limiting assembly 213, and the length of the second forming groove can also be adjusted, and this application will not go into details.

[0159] Specifically, the insulating feeding device 300 further includes a second transverse moving assembly (not shown), which is connected to the second extruding assembly and is used to drive the second extruding assembly to move along the width direction of the second rolling gap so that the insulating material falls into the second forming groove in the center, effectively ensuring the film forming quality. The structure of the second transverse moving assembly is the same as that of the first transverse moving assembly 214, and this application will not elaborate on it.

[0160] Specifically, the insulating feeding device 300 also includes a second vertical moving assembly (not shown), which is connected to the second transverse moving assembly, and is used to drive the second extruding assembly to approach or move away from the second roller assembly 310, so that the insulating material falls from the discharge end of the second barrel into the second forming groove at a moderate distance, effectively preventing the insulating material from being broken or piled between the discharge end of the second barrel and the second forming groove. Among them, the structure of the second vertical moving assembly is the same as that of the first vertical moving assembly 215, and this application will not go into details.

[0161] It can be seen that the structure of the insulating feeding device 300 is the same as that of the conductive feeding device 210 .

[0162] Exemplarily, at least one insulating feeding device 300 is provided.

[0163] It should be noted that when the insulating layer 13 is initially formed, it is attached to the current collector 11 and can be supported by the current collector 11, so it is not easy to break; and the thickness difference between the initial thickness and the target thickness of the insulating layer 13 and the front and rear pressure difference are small, and the initial strength requirement of the insulating layer 13 is low, so the second roller assembly 310, the second limiting assembly, the second transverse movement assembly and the second vertical movement assembly can be omitted.

[0164] In this embodiment, the number of conductive feeding devices 210 is selected according to the number of surfaces of the current collector 11 provided with the self-supporting film 12. If only one surface of the current collector 11 is provided with the self-supporting film 12, the number of conductive feeding devices 210 is 1; if both surfaces of the current collector 11 are provided with the self-supporting film 12, the number of conductive feeding devices 210 is 2; and so on. Similarly, the number of insulating feeding devices 300 is selected according to the number of surfaces of the current collector 11 provided with the insulating layer 13, which will not be repeated.

[0165] In this embodiment, the number of the first extrusion components 211 is selected according to the number of the self-supporting films 12 on one side of the current collector 11. If the number of the self-supporting films 12 on one side of the current collector 11 is 1, the number of the first extrusion components 211 is 1; if the number of the self-supporting films 12 on one side of the current collector 11 is 2, the number of the first extrusion components 211 is 2; and so on. Similarly, the number of the second extrusion components is selected according to the number of the insulating layers 13 on one side of the current collector 11, and will not be repeated.

[0166] In this embodiment, the current collector 11 includes a front side and a back side along the thickness direction. The front side can be the side of the current collector 11 facing upward on the conveying device 100. Exemplarily, taking the production of a one-in-two-out electrode sheet 10 as an example, the film forming device 200 includes a conductive feeding device 210, and the insulating feeding device 300 is provided with one and includes two second extrusion assemblies, and the two second extrusion assemblies are both located on the front side of the current collector 11, and the two insulating layers 13 extruded by the two second extrusion assemblies just fall on the two side edges of the self-supporting film 12 on the front side of the current collector 11.

[0167] In a feasible embodiment, the conductive feeding device 210 includes N first extrusion assemblies 211, and the insulating feeding device 300 is provided with N and includes two second extrusion assemblies, where N ≥ 1. In this embodiment, the 2N second extrusion assemblies are all located on the front of the current collector 11, and each first extrusion assembly 211 located on the front of the current collector 11 corresponds to two second extrusion assemblies, even if both side edges of each self-supporting film 12 on the front of the current collector 11 are provided with an insulating layer 13, so that the dry preparation equipment of the electrode sheet can produce an electrode sheet 10 with one input and 2N outputs, such as Figure 5 The electrode sheet 10 shown has one inlet and four outlets.

[0168] In this embodiment, the composite rolling device 400 adopts multi-stage continuous rolling, for example, 1-8 stages of continuous rolling. Specifically, the composite rolling device 400 includes multiple stages of second pairs of rollers, and the rolling gap of each stage of the second pairs of rollers decreases along the conveying direction of the current collector 11, and the rolling pressure of each stage of the second pairs of rollers increases, so that the intermediate electrode sheet is gradually rolled into the electrode sheet 10.

[0169] Further, the roller diameter of each level of the second pair of rollers can be adjusted independently. For example, the diameters of the second pair of rollers of different levels along the conveying direction of the current collector 11 are successively reduced or the same to ensure the surface quality of the electrode sheet 10. For example, the roller diameter of the second pair of rollers can be 10mm-500mm. Further, the rotation speed of the second pair of rollers at each level and the pressure on the intermediate pole piece can be individually regulated. In this embodiment, the composite rolling device 400 can roll the intermediate pole piece by hot rolling to further ensure the molding quality of the electrode sheet 10, and the temperature can be 40℃-200℃. Of course, the composite rolling device 400 can also roll the intermediate pole piece by single-stage rolling. Among them, the pressure applied by the composite rolling device 400 to the intermediate pole piece is less than the pressure applied by the membrane rolling device 230 to the self-supporting film 12, thereby ensuring that the self-supporting film 12 will not extend laterally and dissolve with the insulating layer 13. In addition, the composite rolling device 400 is a prior art, and its specific structure will not be described in detail in this application.

[0170] In this embodiment, refer to Figure 1As shown, the dry preparation equipment of the electrode sheet also includes a forming heating device 600, which is arranged between the film forming device 200 and the insulating feeding device 300, and the forming heating device 600 is used to heat the preliminary electrode sheet. In this embodiment, the forming heating device 600 is arranged between the film forming device 200 and the insulating feeding device 300, that is, the insulating layer 13 is not heated by the forming heating device 600, and the heat is only conducted by the heated current collector 11 and the self-supporting film 12. While ensuring that the temperature of the current collector 11 and the self-supporting film 12 is suitable for the forming of the composite rolling device 400, the insulating layer 13 is prevented from being overheated and deformed, and the self-supporting film 12 is prevented from fusing with the active material in the insulating layer 13, which affects the forming quality of the electrode sheet 10.

[0171] Specifically, at least one third roller 530 is arranged between the molding heating device 600 and the composite rolling device 400. The third roller 530 has a supporting function, effectively ensuring that the current collector 11, the self-supporting film 12 and the insulating layer 13 remain linear, and effectively ensuring the molding quality of the electrode sheet 10.

[0172] In this embodiment, refer to Figure 1 As shown, the dry preparation equipment for the electrode sheet further includes a surface density detection device 700 and / or a thickness detection device 800 .

[0173] Specifically, the surface density detection device 700 is disposed on one side of the composite rolling device 400 facing the discharge end of the conveying device 100, and the surface density detection device 700 is used to detect the surface density of the electrode sheet 10 to ensure that the surface quality of the electrode sheet 10 meets the production requirements. Among them, the surface density detection device 700 is a prior art and will not be described in detail here.

[0174] Specifically, the dry preparation equipment of the electrode sheet further includes a thickness detection device 800, which is arranged on one side of the composite rolling device 400 facing the discharge end of the conveying device 100, and is used to detect the thickness of the electrode sheet 10 to ensure that the thickness of the electrode sheet 10 meets the production requirements. The thickness detection device 800 is a prior art and will not be described in detail here.

[0175] In this embodiment, the surface density detection device 700 is located between the thickness detection device 800 and the composite rolling device 400, or the thickness detection device 800 is located between the surface density detection device 700 and the composite rolling device 400. Taking the case where the surface density detection device 700 is located between the thickness detection device 800 and the composite rolling device 400 as an example, a fourth roller 540 is provided between the composite rolling device 400 and the surface density detection device 700, and a fifth roller 550 is provided on the side of the thickness detection device 800 facing the discharge end of the conveyor 100. The fourth roller 540 and the fifth roller 550 are used to ensure the flatness of the electrode sheet 10, thereby ensuring the detection accuracy of the surface density detection device 700 and the thickness detection device 800.

[0176] In a feasible implementation, a density detection device and a thickness detection device 800 may be provided between the trimming device 250 and the first guide roller 241 of each film forming device 200 to facilitate production detection.

[0177] Embodiment 2

[0178] Based on the above content and the same concept, the present application provides a dry method for preparing an electrode sheet, please refer to Figure 6 The preparation method can be applied to the dry preparation device of the electrode sheet described in any of the above embodiments, and it can also be understood that the dry preparation device of the electrode sheet can be based on Figure 6 The preparation method shown is used to prepare the electrode sheet 10. The preparation method comprises the following steps:

[0179] S100, extruding a conductive material into a self-supporting film 12 and transferring the self-supporting film 12 to a current collector 11; the conductive material does not contain a solvent.

[0180] Exemplarily, the conductive material is obtained by dry-mixing and stirring the active material and the conductive agent, and then adding a solid binder for fiberization. Among them, the active material can be divided into lithium battery system, sodium battery system, etc. according to the type of battery, and can be divided into positive electrode active material and negative electrode active material according to the type of electrode. According to the type of battery and the type of electrode, the specific type of active material is different; for example, the positive electrode active material of the lithium ion battery can be selected from metal cobalt, aluminum oxide, titanium oxide, lithium salt (mainly including lithium cobalt oxide (LCO), lithium manganese oxide (LMO), lithium iron phosphate (LFP), ternary materials, etc.). Among them, the solid binder includes at least one of polytetrafluoroethylene, polyvinylidene fluoride, polyethylene oxide, and polyacrylate. According to the percentage content, the mass fraction of the active material is 60%-95%, for example, the mass fraction of the active material is 60%, 65%, 70%, 75%, 80%, 85%, 90% or 95%. The mass fraction of the conductive agent is 5%-30%, for example, the mass fraction of the conductive agent is 5%, 10%, 15%, 20%, 25% or 30%. The mass fraction of the solid binder is 5%-25%, for example, the mass fraction of the solid binder is 5%, 10%, 15%, 20% or 25%. Since the battery formula is existing and mature, and does not affect the purpose of the present invention, it will not be repeated.

[0181] Exemplarily, the temperature of the fiberization treatment may be 40° C.-200° C. For example, the temperature of the fiberization treatment is 40° C., 60° C., 80° C., 100° C., 120° C., 140° C., 160° C. or 200° C.

[0182] Specifically, step S100 includes the following steps:

[0183] Controlling the film forming device 200 to extrude the conductive material into a self-supporting film 12 and transfer it to the current collector 11, specifically, comprising the following steps:

[0184] S110 , extruding the conductive material into a self-supporting film 12 .

[0185] Specifically, the conductive feeding device 210 is controlled to extrude the conductive material into a self-supporting film 12 .

[0186] Exemplarily, during the forming process, the self-supporting film 12 is also rolled. Specifically, the first roller assembly 212 is controlled to roll the self-supporting film 12. The rolling method may be vertical rolling. The rolling method may be hot pressing, and the rolling temperature may be controlled at 40°C-200°C. For example, the rolling temperature is 40°C, 60°C, 80°C, 100°C, 120°C, 140°C, 160°C or 200°C.

[0187] S120 , heating the self-supporting film 12 .

[0188] Specifically, the first heating device 220 is controlled to heat the self-supporting film 12. The heating method may be electromagnetic heating, infrared heating or resistance wire heating, and the heating temperature may be controlled at 100°C-300°C. For example, the heating temperature is 100°C, 120°C, 150°C, 180°C, 200°C, 220°C, 250°C, 280°C or 300°C.

[0189] S130 , rolling the self-supporting film 12 .

[0190] Specifically, the film rolling device 230 is controlled to roll the self-supporting film 12. The rolling method may be multi-stage rolling. The rolling method may be hot pressing, and the rolling temperature may be controlled at 40°C-200°C. For example, the rolling temperature is 40°C, 60°C, 80°C, 100°C, 120°C, 140°C, 160°C or 200°C.

[0191] Specifically, the membrane rolling device 230 includes multiple first pairs of rollers. Exemplarily, along the conveying direction of the current collector 11, the rolling gap of each first pair of rollers decreases, and the rolling pressure of each first pair of rollers increases.

[0192] Exemplarily, after rolling the self-supporting film 12, the surface density and / or thickness of the self-supporting film 12 can also be detected. Specifically, the corresponding surface density detection device 700 is controlled to detect the surface density of the self-supporting film 12 and / or the corresponding thickness detection device 800 is controlled to detect the thickness of the self-supporting film 12.

[0193] S140 , transferring the self-supporting film 12 onto the current collector 11 .

[0194] Specifically, the conveying roller set 240 is controlled to guide the self-supporting film 12 to be transferred onto the current collector 11 .

[0195] Exemplarily, before the self-supporting film 12 is transported, the self-supporting film 12 may be cut. Specifically, the trimming device 250 is controlled to cut the self-supporting film 12. In this embodiment, the trimming method includes but is not limited to laser cutting, tungsten steel knife cutting or ceramic knife cutting.

[0196] S200 , stacking the self-supporting film 12 and the current collector 11 together to form a preliminary electrode sheet.

[0197] Specifically, step S200 includes:

[0198] The conveying device 100 is controlled to stack the self-supporting film 12 and the current collector 11 together to form a preliminary electrode sheet.

[0199] Preferably, the laminating roller 130 is controlled to laminate the self-supporting film 12 and the current collector 11 together to form a preliminary pole piece.

[0200] S300, extruding the insulating material to form the insulating layer 13 and attaching the empty foil area of ​​the preliminary pole piece to form the intermediate pole piece; the insulating material does not contain a solvent.

[0201] Specifically, step S300 includes the following steps:

[0202] The insulating material feeding device 300 is controlled to extrude the insulating material into an insulating layer 13 and attach it to the empty foil area of ​​the preliminary pole piece to form an intermediate pole piece.

[0203] Exemplarily, the insulating material is obtained by dry-mixing ceramic powder and solid binder, stirring them uniformly, and then performing a fiberization treatment. The ceramic powder includes at least one of aluminum oxide, boehmite, and silicon oxide. The solid binder includes at least one of polytetrafluoroethylene, polyvinylidene fluoride, polyethylene oxide, and polyacrylate.

[0204] For example, in terms of percentage, the mass fraction of the solid binder is 5%-15%, for example, the mass fraction of the solid binder is 5%, 8%, 10%, 12% or 15%. The mass fraction of the ceramic powder is 85%-95%. For example, the mass fraction of the ceramic powder is 85%, 88%, 90%, 92% or 95%.

[0205] Exemplarily, the temperature of the fiberization treatment is 40° C.-200° C. For example, the temperature of the fiberization treatment is 40° C., 60° C., 80° C., 100° C., 120° C., 140° C., 160° C. or 200° C.

[0206] S400 , rolling the middle electrode sheet into an electrode sheet 10 .

[0207] Specifically, step S300 specifically includes: controlling the composite rolling device 400 to roll-form the intermediate electrode sheet into the electrode sheet 10;

[0208] In this embodiment, after the electrode sheet 10 is roll-formed, the surface density and / or thickness of the electrode sheet 10 is also detected. Specifically, the corresponding surface density detection device 700 is controlled to detect the surface density of the electrode sheet 10 and / or the corresponding thickness detection device 800 is controlled to detect the thickness of the electrode sheet 10.

[0209] For the specific execution process and effects of each device in the above steps, please refer to the above related introduction, which will not be repeated here.

[0210] The present embodiment provides a dry preparation method for an electrode sheet, which can realize dry forming of a self-supporting film and an insulating layer, so that the insulating layer is distributed in the empty foil area of ​​the current collector, effectively preventing the dry electrode sheet from generating burrs during the die-cutting process, thereby ensuring the safety of the battery cell; and solving the problem of mutual dissolution caused by the lateral extension of the self-supporting film and the insulating layer.

[0211] Embodiment 3

[0212] This embodiment provides an electrode sheet prepared by the above-mentioned dry preparation equipment or the above-mentioned dry preparation method, which effectively prevents the problem of burrs on the dry electrode sheet during the die-cutting process, ensures the safety of the battery cell; and solves the problem of mutual dissolution caused by the lateral extension of the self-supporting film and the insulating layer.

[0213] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A dry method for preparing an electrode sheet, characterized in that: It comprises a conveying device (100), a film forming device (200), an insulating material feeding device (300) and a composite rolling device (400); wherein: The conveying device (100) is used to convey the current collector (11); The film forming device (200), the insulating feeding device (300) and the composite rolling device (400) are arranged in sequence along the conveying direction of the current collector (11); The film forming device (200) is used to extrude the conductive material into a self-supporting film (12) and convey it to the conveying device (100), wherein the conductive material does not contain a solvent; the film forming device (200) comprises a conductive feeding device (210), a first heating device (220), a film rolling device (230) and a conveying roller group (240) which are arranged in sequence along the conveying direction of the conductive material; the conductive feeding device (210) is used to extrude the conductive material into the self-supporting film (12); the first heating device (220) is used to heat the self-supporting film (12); the film rolling device (230) is used to roll the self-supporting film (12); the conveying roller group (240) is used to guide the self-supporting film (12) to be conveyed to the conveying device (100); The structure of the insulating feeding device (300) is the same as that of the conductive feeding device (210); The conductive feeding device (210) comprises a first roller assembly (212), a first limit assembly (213), and at least one first extrusion assembly (211), wherein the first extrusion assembly (211) comprises a first barrel (2111); The first roller assembly (212) is arranged at the discharge end of the first barrel (2111), and the first roller assembly (212) is used to roll the conductive material to form the self-supporting film (12); A first forming groove is formed between the first limiting assembly (213) and the first roller assembly (212), the first forming groove being used to limit the forming width of the self-supporting film (12); The conveying device (100) is used to stack the self-supporting film (12) and the current collector (11) together to form a preliminary pole piece; The insulating material feeding device (300) is used to extrude the insulating material into an insulating layer (13) and attach it to the empty foil area of ​​the preliminary pole piece to form an intermediate pole piece, and the insulating material does not contain a solvent; The composite rolling device (400) is used to roll-press the intermediate electrode sheet into an electrode sheet (10).

2. The dry method preparation equipment for electrode sheet according to claim 1, characterized in that: The first extrusion assembly (211) further comprises a first screw rod (2112) disposed in the first barrel (2111) and a first driving member (2113) connected to the first screw rod (2112), wherein the first driving member (2113) is used to drive the screw rod to rotate and extrude the conductive material in the first barrel (2111).

3. The dry method preparation equipment for electrode sheet according to claim 1, characterized in that: The first barrel (2111) is provided with a feeding end and the discharging end in sequence from top to bottom along the vertical direction, and the discharging end of the first barrel (2111) is provided with a first discharging nozzle (21111); The first roller assembly (212) comprises a first upper roller and a first lower roller which are arranged opposite to each other, a first rolling gap is arranged between the first upper roller and the first lower roller, and the first discharge nozzle (21111) is arranged towards the first rolling gap.

4. The dry method preparation equipment for electrode sheet according to claim 3, characterized in that: The conductive feeding device (210) further comprises a first transverse moving assembly (214), the first transverse moving assembly (214) being connected to the first extruding assembly (211), the first transverse moving assembly (214) being used to drive the first extruding assembly (211) to move along the width direction of the first rolling gap; The conductive feeding device (210) further comprises a first vertical movement component (215), wherein the first vertical movement component (215) is connected to the first transverse movement component (214), and the first vertical movement component (215) is used to drive the first extrusion component (211) to move closer to or away from the first roller component (212).

5. The dry method preparation equipment for electrode sheet according to claim 1, characterized in that: The film forming device (200) comprises at least one conductive feeding device (210).

6. The dry method preparation equipment for electrode sheet according to claim 1, characterized in that: The film forming device (200) further comprises a trimming device (250) arranged between the film rolling device (230) and the conveying roller group (240), wherein the trimming device (250) is used for cutting the self-supporting film (12).

7. The dry method preparation equipment of the electrode sheet according to claim 1, characterized in that: The insulating feeding device (300) comprises at least one second extruding component, the second extruding component comprising a second barrel, a second screw rod arranged in the second barrel, and a second driving member connected to the second screw rod, the second driving member being used to drive the screw rod to rotate and extrude the insulating material in the second barrel; The second barrel is provided with a feeding end and a discharging end in sequence from top to bottom along the vertical direction, and the discharging end of the second barrel is provided with a second discharging nozzle.

8. The dry method preparation equipment for electrode sheet according to claim 7, characterized in that: The insulating material feeding device (300) further comprises a second roller assembly (310), the second roller assembly (310) being arranged at the discharge end of the second barrel, the second roller assembly (310) being used for rolling the insulating material to form the insulating layer (13); The second rolling roller assembly (310) comprises a second upper rolling roller and a second lower rolling roller which are arranged opposite to each other, a second rolling gap is arranged between the second upper rolling roller and the second lower rolling roller, and the second discharge nozzle is arranged towards the second rolling gap.

9. The dry method preparation equipment for electrode sheet according to claim 8, characterized in that: The insulating feeding device (300) further comprises a second limiting assembly, wherein a second forming groove is formed between the second limiting assembly and the second roller assembly (310), and the second forming groove is used to limit the forming width of the insulating layer (13).

10. The dry method preparation equipment for electrode sheet according to claim 8, characterized in that: The insulating feeding device (300) further comprises a second transverse movement component, the second transverse movement component is connected to the second extrusion component, and the second transverse movement component is used to drive the second extrusion component to move along the width direction of the second rolling gap.

11. The dry method preparation equipment for electrode sheet according to claim 10, characterized in that: The insulating feeding device (300) further comprises a second vertical movement assembly, the second vertical movement assembly being connected to the second transverse movement assembly, the second vertical movement assembly being used to drive the second extrusion assembly to approach or move away from the second roller assembly (310).

12. The dry method preparation equipment for electrode sheet according to claim 1, characterized in that: The insulating feeding device (300) is provided as at least one.

13. The dry method preparation device for electrode sheets according to any one of claims 1 to 12, characterized in that: The dry method preparation equipment for the electrode sheet further comprises a forming and heating device (600), wherein the forming and heating device (600) is arranged between the film forming device (200) and the insulating feeding device (300), and the forming and heating device (600) is used to heat the preliminary electrode sheet.

14. The dry method preparation device for electrode sheets according to any one of claims 1 to 12, characterized in that: The dry method preparation device for the electrode sheet further comprises a surface density detection device (700), wherein the surface density detection device (700) is arranged on a side of the composite rolling device (400) facing the discharge end of the conveying device (100), and the surface density detection device (700) is used to detect the surface density of the electrode sheet; and / or, The dry preparation equipment for the electrode sheet further comprises a thickness detection device (800), wherein the thickness detection device (800) is arranged on a side of the composite rolling device (400) facing the discharge end of the conveying device (100), and the thickness detection device (800) is used to detect the thickness of the electrode sheet (10).

15. A dry method for preparing an electrode sheet, characterized in that: The following steps are involved: S100, extruding a conductive material into a self-supporting film (12) and transferring the film to a current collector (11); the conductive material does not contain a solvent; Step S100 specifically includes the following steps: S110, extruding the conductive material to form the self-supporting film (12); specifically, the conductive material is extruded and rolled to form the self-supporting film (12), and the forming width of the self-supporting film (12) is limited; S120, heating the self-supporting film (12); S130, rolling the self-supporting film (12); S140, transferring the self-supporting film (12) onto the current collector (11); S200, stacking the self-supporting film (12) and the current collector (11) together to form a preliminary pole piece; S300, extruding an insulating material to form an insulating layer (13) and attaching the insulating material to the empty foil area of ​​the preliminary electrode to form an intermediate electrode; the insulating material does not contain a solvent; S400, rolling the intermediate electrode sheet into an electrode sheet (10).

16. The dry method for preparing an electrode sheet according to claim 15, characterized in that: The following steps are involved: Step S100 specifically comprises: controlling the film forming device (200) to extrude the conductive material into the self-supporting film (12) and transfer the self-supporting film (12) to the current collector (11); The conductive material is obtained by dry-mixing the active material and the conductive agent, stirring them uniformly, and then adding a solid binder to perform a fiberization treatment; The active material is a positive electrode active material or a negative electrode active material; The solid binder includes at least one of polytetrafluoroethylene, polyvinylidene fluoride, polyethylene oxide, and polyacrylate; The temperature of the fiberization treatment is 40°C-200°C.

17. The dry method for preparing an electrode sheet according to claim 15, characterized in that: Step S200 specifically comprises: controlling the lamination roller (130) to laminate the self-supporting film (12) and the current collector (11) together to form the preliminary pole piece.

18. The dry method for preparing an electrode sheet according to claim 15, characterized in that: Step S300 specifically comprises: controlling the insulating material feeding device (300) to extrude the insulating material into the insulating layer (13) and conveying it to the empty foil area of ​​the preliminary pole piece to form the intermediate pole piece; The insulating material is obtained by dry-mixing ceramic powder and solid binder and stirring them uniformly, and then performing a fiberization treatment; The ceramic powder includes at least one of alumina, boehmite, and silicon oxide; The solid binder includes at least one of polytetrafluoroethylene, polyvinylidene fluoride, polyethylene oxide, and polyacrylate; In terms of percentage, the mass fraction of the solid binder is 5%-15%, and the mass fraction of the ceramic powder is 85%-95%; The temperature of the fiberization treatment is 40°C-200°C.

19. The dry method for preparing an electrode sheet according to claim 15, characterized in that: Step S400 specifically comprises: controlling the composite rolling device (400) to roll-form the intermediate electrode sheet into the electrode sheet (10); After the electrode sheet (10) is formed by roll forming, the surface density and / or thickness of the electrode sheet (10) is also detected; The surface density detection device (700) is controlled to detect the surface density of the electrode sheet (10) and / or the thickness detection device (800) is controlled to detect the thickness of the electrode sheet (10).

20. The dry method for preparing an electrode sheet according to claim 15, characterized in that: Step S110 specifically includes the following steps: Controlling the conductive feeding device (210) to extrude the conductive material into the self-supporting film (12); During the forming process, the first roller assembly (212) is also controlled to roll the self-supporting film (12); The rolling method is vertical rolling; The rolling method is hot pressing; The rolling temperature is 40°C-200°C.

21. The dry method for preparing an electrode sheet according to claim 15, characterized in that: Step S120 specifically includes the following steps: controlling the first heating device (220) to heat the self-supporting film (12); The heating method is electromagnetic heating, infrared heating or resistance wire heating; The heating temperature is 100°C-300°C.

22. The dry method for preparing an electrode sheet according to claim 15, characterized in that: Step S130 specifically includes the following steps: Controlling the film rolling device (230) to roll the self-supporting film (12); The rolling method is multi-stage rolling; the film rolling device (230) comprises a multi-stage first pair of rollers; Along the conveying direction of the current collector (11), the rolling gap of the first pair of rollers at each stage decreases, and the rolling pressure of the first pair of rollers at each stage increases; The roller pressing method is hot pressing; The rolling temperature is 40°C-200°C.

23. The dry method for preparing an electrode sheet according to claim 15, characterized in that: After the self-supporting film (12) is rolled, the surface density and / or thickness of the self-supporting film (12) is also detected; the surface density detection device (700) is controlled to detect the surface density of the self-supporting film (12) and / or the thickness detection device (800) is controlled to detect the thickness of the self-supporting film (12).

24. The dry method for preparing an electrode sheet according to claim 15, characterized in that: Step S140 specifically includes the following steps: Controlling the conveying roller group (240) to guide the self-supporting film (12) to be conveyed onto the current collector (11); Before conveying the self-supporting film (12), controlling a trimming device (250) to trim the self-supporting film (12); The cutting method is laser cutting, tungsten steel knife cutting or ceramic knife cutting.

25. An electrode sheet, characterized in that: The electrode sheet is prepared using the dry preparation equipment of the electrode sheet according to any one of claims 1 to 14 or is prepared by the dry preparation method of the electrode sheet according to any one of claims 15 to 24.

Images