CN116525753A

CN116525753A - Preparation method and preparation device of composite pole piece and lithium ion battery

Info

Publication number: CN116525753A
Application number: CN202310761042.6A
Authority: CN
Inventors: 施展; 冯玉川; 李峥
Original assignee: Suzhou Qingtao New Energy S&T Co Ltd
Current assignee: Suzhou Qingtao New Energy S&T Co Ltd
Priority date: 2023-06-27
Filing date: 2023-06-27
Publication date: 2023-08-01
Anticipated expiration: 2043-06-27
Also published as: CN116525753B

Abstract

The application relates to a preparation method of a composite pole piece, a preparation device of the composite pole piece for preparing the composite pole piece and a lithium ion battery comprising the composite pole piece. The preparation method of the composite pole piece comprises the steps of firstly conveying the electrode pole piece through an electrode pole piece unreeling mechanism, so that the electrode pole piece passes through a gap in the middle of a shaping roller; then conveying the solid electrolyte membrane through a solid electrolyte membrane unreeling mechanism positioned at the side edge of the electrode pole piece unreeling mechanism, so that the solid electrolyte membrane passes through a gap between the shaping roller and the electrode pole piece; finally, rolling the solid electrolyte membrane positioned on the side surface of the electrode plate on the electrode plate through a shaping roller to obtain a composite electrode plate; wherein, be provided with the elastic component between design roller and the solid electrolyte membrane. The composite pole piece preparation device for preparing the composite pole piece comprises a shaping roller, an electrode pole piece unreeling mechanism, a solid electrolyte membrane unreeling mechanism and an elastic piece arranged between the shaping roller and the solid electrolyte membrane.

Description

Preparation method and preparation device of composite pole piece and lithium ion battery

Technical Field

The application relates to the technical field of batteries, in particular to a preparation method of a composite pole piece, a device for preparing the composite pole piece and a lithium ion battery comprising the composite pole piece.

Background

Lithium ion batteries are currently the main stream of the market, have wide application prospect, and along with the continuous emergence of new technology, the requirements on battery performance are also higher and higher. Conventional liquid batteries using nonaqueous electrolyte as an electrolyte system have many safety concerns, such as flammability and explosiveness of conventional electrolyte materials, and safety problems of batteries caused by undesirable side reactions of positive electrode materials, particularly high-energy-density high-nickel ternary materials, with electrolytes.

At present, the method for compounding the solid electrolyte on the electrode surface mainly comprises the steps of coating the solid electrolyte slurry on the electrode surface in a coating mode, wherein the mode can be directly inlaid in the current mature coating process, but simultaneously has a plurality of problems, for example, (1) in the drying process after coating, the surface tension of the electrode pole piece is rapidly changed due to rapid drying and volatilization of a solvent, the electrode pole piece is easily curled and edge-raised, and meanwhile, the crystallization binder is segregated on the pole piece surface due to rapid volatilization of the solvent; (2) Some electrolyte materials, such as sulfide solid state electrolytes, are extremely sensitive to moisture, and small amounts of moisture present in wet processes tend to corrode the electrolyte materials; (3) Part of the novel adhesive has a matching problem with the solvent, and the novel solvent needs to be developed to adapt to the novel adhesive; (4) The wet process consumes a large amount of solvent, and the environmental treatment cost is too high.

At present, a method for preparing an electrode plate by a dry method is reported, and meanwhile, a lithium ion battery for preparing an electrode and a solid electrolyte membrane by molding through a lamination-like technology in a laboratory test stage is known. However, continuous production of the composite electrode before cutting is still not realized at present, and therefore, how to design and improve the existing equipment and prepare the composite electrode is a very troublesome technical problem.

Disclosure of Invention

Based on the above, the first aspect of the invention provides a preparation method of a composite pole piece, which improves the consistency of the transverse thickness of the composite pole piece by adjusting the stress condition of the electrode pole piece and the solid electrolyte membrane in the rolling process.

A preparation method of a composite pole piece comprises the following steps:

conveying the electrode pole piece through an electrode pole piece unreeling mechanism, so that the electrode pole piece passes through a gap in the middle of the shaping roller;

conveying the solid electrolyte membrane through a solid electrolyte membrane unreeling mechanism positioned at the side edge of the electrode pole piece unreeling mechanism, so that the solid electrolyte membrane passes through a gap between the shaping roller and the electrode pole piece; and

the solid electrolyte membrane positioned on the side surface of the electrode pole piece is pressed on the electrode pole piece by a shaping roller to obtain a composite pole piece;

wherein, elastic pieces are arranged between the shaping roller and the solid electrolyte membrane on the electrode pole piece; the yield limit of the elastic member satisfies: when the solid electrolyte membrane and the electrode pole piece pass through the gap between the shaping rollers, the solid electrolyte membrane and the electrode pole piece are subjected to plastic deformation, and the elastic piece is subjected to elastic deformation.

The width of the elastic piece is larger than or equal to the minimum value of the width of the solid electrolyte membrane or the electrode pole piece.

The electrode sheet comprises a positive electrode sheet and/or a negative electrode sheet.

In some embodiments, the elastic member is a protective film that is transported through a gap between the shaping roller and the solid electrolyte membrane.

In some embodiments, the elastic member is a glue layer that surrounds and covers the outside of the sizing roller.

In some embodiments, solid electrolyte membranes respectively positioned at two sides of the electrode pole piece are pressed on the electrode pole piece by a shaping roller to obtain the composite pole piece.

In some embodiments, the method further comprises separating the substrate overlying the solid electrolyte membrane from the composite pole piece.

In some embodiments, the protective film is a polymeric film or a nonwoven.

In some embodiments, the glue layer is plastic, rubber, or silicone.

In some embodiments, the method of making further comprises: the composite pole piece is received by a composite pole piece winding mechanism at the downstream of the shaping roller;

receiving a substrate through a substrate winding mechanism between the shaping roller and the composite pole piece winding mechanism;

the substrate winding mechanism and the solid electrolyte membrane unwinding mechanism are positioned on the same side of the electrode pole piece unwinding mechanism.

In some embodiments, the method of making further comprises: conveying the elastic piece through a protective film unreeling mechanism; the protective film unreeling mechanism is positioned between the solid electrolyte film unreeling mechanism and the shaping roller; and

and the elastic piece is received between the shaping roller and the substrate winding mechanism through the protective film winding mechanism.

The second aspect of the application provides a composite pole piece, which is obtained by the preparation method of the composite pole piece in the first aspect.

A third aspect of the present application provides a lithium ion battery, which includes a composite pole piece prepared by the preparation method of the composite pole piece of the first aspect.

A fourth aspect of the present application provides a device for preparing a composite pole piece, the device comprising:

the shaping roller comprises a first shaping roller and a second shaping roller;

the electrode pole piece unreeling mechanism is positioned at the upstream of the shaping roller and is used for conveying the electrode pole piece so that the electrode pole piece passes through a gap between the first shaping roller and the second shaping roller; and

the solid electrolyte membrane unreeling mechanism is positioned at the side edge of the electrode pole piece unreeling mechanism and is used for conveying the solid electrolyte membrane so that the solid electrolyte membrane passes through a gap between the first shaping roller and the second shaping roller;

An elastic piece is arranged between the shaping roller and the solid electrolyte membrane.

In some embodiments, the apparatus further comprises: the composite pole piece winding mechanism is positioned at the downstream of the shaping roller and is used for receiving the composite pole piece; and

the base material winding mechanism is arranged between the shaping roller and the composite pole piece winding mechanism and is used for receiving the base material covered on the solid electrolyte membrane; the substrate winding mechanism and the solid electrolyte membrane unwinding mechanism are positioned on the same side of the electrode pole piece unwinding mechanism.

In some embodiments, the apparatus further comprises: the protective film unreeling mechanism is positioned between the solid electrolyte film unreeling mechanism and the shaping roller and is used for conveying the elastic piece; and

the protective film winding mechanism is positioned between the shaping roller and the base material winding mechanism and is used for receiving the elastic piece;

the elastic piece is a protective film.

In some embodiments, the elastic member may also be a glue layer that surrounds and covers the outside of the sizing roller.

According to the preparation method of the composite electrode plate, in the rolling process of the shaping roller, the solid electrolyte membrane can better cover the electrode plate through the buffer provided by the elastic piece; meanwhile, in the rolling process of the shaping roller, the stress of the middle area of the electrode plate is larger than that of the edge area due to the fact that the middle thickness of the electrode plate is thicker, and the transverse thickness of the electrode plate tends to be consistent after rolling. The negative influence on the rolling composite process caused by the phenomena of thick middle and thin two ends of the electrode pole piece is avoided, the electrode pole piece is protected from being crushed, and meanwhile, the active substance layer in the electrode pole piece and the solid electrolyte membrane can be better combined. In addition, the composite pole piece prepared by the preparation method is applied to the battery, so that the overall safety performance of the battery is improved; meanwhile, the method and the device roll in the composite process of the solid electrolyte membrane and the electrode pole piece, realize the edge bulging phenomenon in the rolling process to be solved when the electrode pole piece is edging, and avoid the influence of edge thinning on interlayer composite.

Drawings

Fig. 1 is a flowchart of a preparation method of a composite pole piece provided in an embodiment of the present application.

Fig. 2 is a schematic structural diagram of a composite pole piece before rolling provided in an embodiment of the present application.

Fig. 3 is a schematic structural diagram of a rolled composite pole piece according to an embodiment of the present application.

Fig. 4 is a schematic structural diagram of a device for preparing a composite pole piece according to embodiment 1 of the present application.

Fig. 5 is a schematic structural diagram of a device for preparing a composite pole piece according to embodiment 3 of the present application.

Fig. 6 is a schematic structural diagram of a device for preparing a composite pole piece according to comparative example 1 of the present application.

Description of the reference numerals

1. Electrode pole pieces; 2. a solid electrolyte membrane;

11. an electrode pole piece unreeling mechanism; 12. a composite pole piece winding mechanism;

21. a solid electrolyte membrane unreeling mechanism; 22. a substrate winding mechanism;

31. a first forming roller; 32. a second shaping roller;

41. a protective film unreeling mechanism; 42. a protective film winding mechanism;

51. a first guide roller; 52. a second guide roller; 53. a third guide roller; 54. and a fourth guide roller.

Detailed Description

In order to make the above objects, features and advantages of the present application more comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. This application is, however, susceptible of embodiment in many other forms than those described herein and similar modifications can be made by those skilled in the art without departing from the spirit of the application, and therefore the application is not to be limited to the specific embodiments disclosed below.

In the description of the present application, it should be understood that, if there are terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., these terms refer to the orientation or positional relationship based on the drawings, which are merely for convenience of description and simplification of description, and do not indicate or imply that the apparatus or element referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present application.

Furthermore, the terms "first," "second," and the like, if any, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present application, the terms "plurality" and "a plurality" if any, mean at least two, such as two, three, etc., unless specifically defined otherwise.

In this application, unless explicitly stated and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly. For example, the two parts can be fixedly connected, detachably connected or integrated; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the terms in this application will be understood by those of ordinary skill in the art as the case may be.

In this application, unless expressly stated or limited otherwise, the meaning of a first feature being "on" or "off" a second feature, and the like, is that the first and second features are either in direct contact or in indirect contact through an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.

It will be understood that if an element is referred to as being "fixed" or "disposed" on another element, it can be directly on the other element or intervening elements may also be present. If an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein, if any, are for descriptive purposes only and do not represent a unique embodiment.

The direction parallel to the running direction of the electrode pole piece is defined as a longitudinal direction, and the direction perpendicular to the running direction of the electrode pole piece is defined as a transverse direction.

Referring to fig. 4-5, the composite pole piece preparation device comprises a shaping roller, an electrode pole piece unreeling mechanism, a solid electrolyte membrane unreeling mechanism and a composite pole piece reeling mechanism. The shaping rollers comprise a first shaping roller and a second shaping roller which are symmetrically arranged on two sides of the electrode pole piece; the connecting line between the axes of the first shaping roller and the second shaping roller is perpendicular to the conveying direction of the electrode pole piece.

The electrode sheet unreeling mechanism is located at the upstream of the shaping roller and is used for unreeling the electrode sheet, and then the electrode sheet is conveyed so that the electrode sheet passes through a gap between the first shaping roller and the second shaping roller.

The solid electrolyte membrane unreeling mechanism is positioned at the upstream of the shaping roller, and more specifically is positioned between the electrode pole piece unreeling mechanism and the shaping roller. The solid electrolyte membrane unreeling mechanism is used for unreeling the solid electrolyte membrane, and then conveying the solid electrolyte membrane to enable the solid electrolyte membrane to pass through a gap between the first shaping roller and the second shaping roller, and more particularly, the solid electrolyte membrane unreeling mechanism enables the solid electrolyte membrane to pass through a gap between the electrode pole piece and the shaping roller.

The composite pole piece winding mechanism is positioned at the downstream of the shaping roller and is used for providing a pulling force for the electrode pole piece along the movement direction of the electrode pole piece and receiving the composite pole piece obtained after being rolled by the shaping roller to finish winding action.

In some embodiments, the number of the solid electrolyte membrane unreeling mechanisms is two, the solid electrolyte membrane unreeling mechanisms are respectively positioned at two sides of the electrode pole piece unreeling mechanisms, then the solid electrolyte membrane is conveyed so that two layers of solid electrolyte membranes respectively pass through a gap between the first shaping roller and the second shaping roller, and the electrode pole piece is positioned between the two layers of solid electrolyte membranes.

Alternatively, the two solid electrolyte membrane unreeling mechanisms are symmetrically arranged at two sides of the electrode pole piece unreeling mechanism.

In some embodiments, the apparatus for producing a composite pole piece further comprises a substrate winding mechanism.

When the base material is arranged on the solid electrolyte membrane, the base material covers one side of the solid electrolyte membrane far away from the electrode plate, and the base material is required to be separated after the electrode plate and the solid electrolyte membrane are rolled by a shaping roller to obtain the composite electrode plate. The substrate is separated from the composite pole piece by arranging a substrate winding mechanism at the downstream of the shaping roller. In the separation process, the substrate winding mechanism can provide tension for the substrate of the solid electrolyte membrane, so that the substrate is separated from the composite pole piece, and the action of winding the substrate is finished if necessary.

The number of the substrate winding mechanisms corresponds to the number of the solid electrolyte membrane unreeling mechanisms.

In some embodiments, an elastic member is disposed between the first sizing roller and the second sizing roller.

The yield limit of the elastic member satisfies: when the solid electrolyte membrane and the electrode pole piece pass through the gap between the shaping rollers, the solid electrolyte membrane and the electrode pole piece are subjected to plastic deformation, and the deformation of the elastic piece is changed into elastic deformation.

Elastic deformation refers to the change of the relative position between the points of the solid under the action of external force, and is called elastic deformation when the external force is removed and the solid is restored.

When an object receives a large force beyond the elastic limit, the object may break or deform, and cannot return to the original shape, which is called plastic deformation.

The application improves the interlayer binding force between the solid electrolyte membrane and the electrode slice membrane through plastic deformation formed between the solid electrolyte membrane and the electrode slice membrane.

It will be appreciated that, on the basis of satisfying the above conditions, there is no particular requirement for the rolling pressure, and the corresponding rolling pressure is still considered to be within the scope of the present application according to the choice of the material system, and is merely illustrative, and not limiting, of the scope of protection, and the rolling pressure is 10-1000 MPa.

In the electrode plate production process, in order to smoothly carry out the subsequent rolling process, the edge of the electrode plate is usually thinned, and the existence of the thinned area of the electrode plate leads the bonding of the solid electrolyte membrane and the electrode plate to be affected.

Surprisingly, the composite pole piece preparation device provided by the application utilizes the buffer provided by the elastic piece when in rolling, so that the solid electrolyte membrane can better cover the electrode pole piece; meanwhile, in the rolling process of the shaping roller, the stress of the middle area of the electrode pole piece is larger than that of the edge area due to the fact that the middle thickness of the electrode pole piece is thick, and the transverse thickness of the electrode pole piece tends to be consistent after rolling.

In some embodiments, the solid electrolyte membrane has a thickness of 1-30 μm; preferably 3-20 μm; more preferably 3-15 μm.

The application of a solid electrolyte coating to the electrode surface, particularly the surface of a positive electrode of high capacity, can effectively improve the safety performance of the battery. But is limited by the energy density, the thickness of the solid electrolyte membrane is generally thin, which is an order of magnitude smaller than the dry-process electrode sheet, which makes the solid electrolyte membrane susceptible to cracking when the electrode sheet is dry-process compounded.

The elastic piece is made of flexible materials, the flexible materials are elastically deformed under the action of pressure, and the thickness of the middle area and the thickness of the thinned area of the electrode pole piece tend to be consistent under the action of pressure due to the tiny elastic deformation, so that the electrode pole piece can be well attached to the solid electrolyte membrane.

In some embodiments of the invention, the flexible material is a polymer.

The material of the polymer is not particularly limited, and can be exemplified by plastics such as polytetrafluoroethylene, polyethylene terephthalate, polypropylene, polyacrylonitrile and the like, rubbers such as HEPA (high performance polyethylene) rubber, silicone rubber, fluororubber and the like, and elastic materials such as silica gel and the like which can deform to a certain extent.

The thickness of the elastic member is not particularly limited in the present application, and the necessary adjustment of the thickness of the elastic member is understood to be within the scope of the present application without departing from the inventive concept of the present application.

In some embodiments, the elastic member is a layer of adhesive that surrounds and covers the outside of the two sizing rollers.

The composite pole piece preparation device of the application also comprises a protective film unreeling mechanism for unreeling the protective film. The protective film unreeling mechanism is positioned at the upstream of the shaping roller and is arranged between the solid electrolyte film unreeling roller and the shaping roller. In the rolling compounding process of the electrode pole piece and the solid electrolyte membrane, the protective film is positioned in the gap between the shaping roller and the solid electrolyte membrane.

The present application has no special requirements on the structure of the protective film, and on the basis of not departing from the inventive concept of the present application, it is known that a film layer capable of generating a certain degree of elastic deformation under a certain pressure can be used in the present application, and the protective film can be selected from a polymer film or a non-woven fabric, and the non-woven fabric includes but is not limited to PP-based non-woven fabric, PE-based non-woven fabric, PET-based non-woven fabric, PAN-based non-woven fabric, PTFE-based non-woven fabric, celgard non-woven fabric, etc., by way of illustration only and not limiting the scope of protection; the polymer film may be selected from PVDF film, PE film, PP film, PE/PP/PE film, PP/PE/PP film, PTFE film, silicone oil release film, fluorine release film, PET film, non-silicon release film, etc. It is understood that the protective film may also be a multilayer structure consisting of two or more layers of polymer film and/or nonwoven fabric.

The thickness of the protective film is not particularly limited, and conventional adjustment of the thickness of the protective film for adjusting the rolling effect is considered to be within the scope of the present application without departing from the inventive concept of the present application, and it is understood that the thickness of the protective film should be the sum of the multilayer structures when the protective film is of the multilayer structure.

In some embodiments, the composite pole piece manufacturing apparatus further comprises a protective film winding mechanism. The protective film winding mechanism is positioned at the downstream of the shaping roller and arranged between the shaping roller and the composite pole piece winding mechanism and is used for providing tension for the protective film and receiving the protective film.

In some embodiments, the composite pole piece manufacturing apparatus further comprises a guide roller.

Optionally, a guide roller is located between the solid electrolyte membrane unwind mechanism and the shaping roller for providing a guide for the solid electrolyte membrane. A guide roller can also be arranged between the shaping roller and the substrate winding mechanism, and the guide roller is used for providing a guide function for the substrate of the solid electrolyte membrane separated from the composite pole piece.

Optionally, a guide roller is located between the protective film unreeling mechanism and the shaping roller for providing a guide function for the protective film. A guide roller can be arranged between the shaping roller and the protective film winding mechanism, and the guide roller is used for providing a guide effect for recycling the protective film.

In some embodiments, the composite pole piece preparation device further comprises an unreeling deviation rectifying component, a pole piece static eliminating component and the like which are sequentially arranged along the unreeling route. The unreeling deviation correcting component can correct unreeling and running routes of the electrode pole pieces, the solid electrolyte membrane and the like, so that the starting material line is kept at the same level. The winding and unwinding mechanism of the main material adopts a single-station deviation correction, and the winding and unwinding of the rest materials adopts cantilever type with deviation correction. The static eliminating assembly performs static eliminating treatment on the two sides of the electrode pole piece, so that friction force between the pole piece and the conveying roller can be reduced. It is understood that known functional components or structures may be used in the present application throughout the process of winding, rolling, unwinding without departing from the inventive concepts of the present application.

In some embodiments, the sizing rolls have a width of 500-800 mm, including but not limited to 500 mm, 550 mm, 600 mm, 650 mm, 700 mm, 750 mm, 800 mm. Preferably 550-650 mm.

In some embodiments, the sizing roller has a roller diameter of 300-500 mm, including but not limited to 300 mm, 350 mm, 400 mm, 450 mm, 500 mm. Preferably 350-450 mm.

Referring to fig. 4-5, in combination with the structure of the composite pole piece preparation device, the preparation method of the composite pole piece of the application comprises the following steps: unreeling the electrode sheet by the electrode sheet unreeling mechanism 11 and conveying the electrode sheet to the composite sheet reeling mechanism 12 so that the electrode sheet passes through a gap between the first shaping roller 31 and the second shaping roller 32; conveying the solid electrolyte membrane through a solid electrolyte membrane unreeling mechanism 21 positioned at the side edge of the electrode pole piece unreeling mechanism 11, so that the solid electrolyte membrane passes through a gap between the shaping roller and the electrode pole piece; then the electrode pole piece and the solid electrolyte membrane are rolled and compounded through a first shaping roller 31 and a second shaping roller 32; when in rolling lamination, an elastic piece is arranged between the shaping roller and the solid electrolyte membrane; finally, downstream of the shaping roller, the composite pole piece is received by a composite pole piece winding mechanism 12.

In some embodiments, the composite electrode sheet comprises an electrode sheet and solid electrolyte membranes respectively positioned at two sides of the electrode sheet. After the electrode sheet is transported, the solid electrolyte membrane is unreeled and transported to the shaping rollers by two solid electrolyte membrane unreeling mechanisms 21 respectively positioned at two sides of the electrode sheet unreeling mechanism 11, so that the two layers of solid electrolyte membranes respectively pass through the gap between the first shaping roller 31 and the second shaping roller 32; in the gap between the first shaping roller 31 and the second shaping roller 32, the two layers of solid electrolyte membranes are attached to the electrode pole piece positioned in the middle of the two layers of solid electrolyte membranes and the elastic piece positioned on the outer side of the two layers of solid electrolyte membranes in pairs, and the solid electrolyte membranes are compounded on the two sides of the electrode pole piece under the rolling action of the shaping rollers; thereby obtaining the composite pole piece.

In some embodiments, the solid electrolyte membrane is formed separately, i.e., the solid electrolyte membrane is formed without the aid of a substrate and the membrane remains intact. At this time, after the electrode pole piece and the solid electrolyte membrane enter a gap of the shaping roller, the composite pole piece is obtained under the pressure action of the shaping roller, and the composite pole piece is wound by the electrode pole piece winding mechanism.

In some embodiments, the solid electrolyte membrane is covered with a substrate to provide support to the solid electrolyte membrane. The solid electrolyte membrane unreeling mechanism 21 makes the base material be located at the side of the solid electrolyte membrane far from the electrode plate when the solid electrolyte membrane is transported. And separating the base material from the composite electrode plate after the solid electrolyte membrane and the electrode plate are compounded. Specifically, the substrate can be received by the substrate winding mechanisms 22 respectively positioned at two sides of the composite pole piece winding mechanism 12, and the substrate winding mechanism 22 is positioned between the shaping roller and the composite pole piece winding mechanism 12.

In some embodiments, the elastic member is a glue layer that surrounds the outer sides of the first and second shaping rollers 31, 32. When the shaping roller rotates, the adhesive layer rotates along with the shaping roller; when the shaping roller is used for rolling the solid electrolyte membrane and/or the electrode pole piece, the adhesive layer provides a buffer effect on the solid electrolyte membrane and/or the electrode pole piece, so that the solid electrolyte membrane can better cover one side or two sides of the electrode pole piece, and meanwhile, the consistency of the transverse thickness of the rolled electrode pole piece is improved.

In some embodiments, the elastic member is a protective film, the protective film may be unwound by two protective film unwinding mechanisms 41 located at the side of the solid electrolyte film unwinding mechanism 21 remote from the electrode sheet, and the protective film unwinding mechanism 41 conveys the protective film to the shaping rollers such that the two protective films pass through gaps between the first shaping roller 31 and the second shaping roller 32, respectively. In the gap between the first shaping roller 31 and the second shaping roller 32, the protective film, the solid electrolyte film, the electrode pole piece, the solid electrolyte film and the protective film are sequentially distributed in pairs, and the solid electrolyte film is compounded on two sides of the electrode pole piece under the rolling action of the shaping rollers; thereby obtaining the composite pole piece.

Alternatively, as shown in fig. 4, the solid electrolyte membrane and the protective film are guided by the guide rollers 51 and 52, respectively, and then reach between the first shaping roller 31 and the second shaping roller 32; the first guide roller 51 is located on the side of the second guide roller 52 remote from the shaping roller. The protective film, together with the solid electrolyte film, rotates toward the shaping roller and then contacts the electrode sheet, passing through the gap between the first shaping roller 31 and the second shaping roller 32, more specifically, the gap between the shaping roller and the electrode sheet. Then the electrode plate and the two layers of solid electrolyte membranes are compounded by rolling down the first shaping roller 31 and the second shaping roller 32.

Alternatively, the solid electrolyte membrane and the protective film are attached upstream of the shaping roller, and then contact with the electrode plate after rotating along with the shaping roller. For example, the protective film is attached to the side of the solid electrolyte membrane away from the electrode sheet at the second guide roller 52, and then the solid electrolyte membrane is contacted and attached to the electrode sheet at the side of the solid electrolyte membrane away from the protective film after the solid electrolyte membrane rotates with the protective film along with the first shaping roller 31 or the second shaping roller 32 to the gap between the first shaping roller 31 or the second shaping roller 32.

When the composite electrode plate is rolled, the shaping roller applies tension to the electrode plate and the solid electrolyte membrane, and the two layers of protective films are positioned between the shaping roller and the solid electrolyte membrane to play a role in buffering, so that the forces applied to all sites of the electrode plate and the solid electrolyte membrane are uniform, the solid electrolyte membrane in the composite electrode plate is finally obtained to almost completely cover the electrode plate, the combination between the electrode plate and the solid electrolyte membrane is better, the consistency of the transverse thickness of the composite electrode plate is improved, and the compaction density is also improved.

In some embodiments, the protective film and the substrate may be separated from the composite pole piece simultaneously.

When there is only one guide roller 53 at the downstream of the shaping roller, after the shaping roller rolls, the composite pole piece continues to be conveyed to the downstream of the shaping roller 32, the protective film and the base material respectively reach the third guide roller 53 along with the rotation of the shaping roller under the action of the protective film winding mechanism 42 and the base material winding mechanism 22, then the protective film and the base material start to separate after rotating around the third guide roller 53 for a certain angle, the protective film moves forward to the protective film winding mechanism 42 and completes the winding action, and the base material moves forward to the base material winding mechanism 22 and completes the winding action.

When there are two guide rollers 53, 54 at the downstream of the shaping roller, after the shaping roller rolls, the composite pole piece continues to be transferred to the downstream of the shaping roller 32, the protective film and the base material respectively reach the third guide roller 53 and the fourth guide roller 54 along with the rotation of the shaping roller under the action of the protective film winding mechanism 42 and the base material winding mechanism 22, and then the protective film moves forward to the protective film winding mechanism 42 and completes the winding action, and the base material moves forward to the base material winding mechanism 22 and completes the winding action.

Alternatively, the guide roller 53 may be replaced with more than two guide rollers; the guide roller 54 may be replaced with more than two guide rollers.

In some embodiments, the protective film may also be separated from the composite pole piece prior to the substrate. After the sizing roller rolls, the composite pole piece continues to be conveyed downstream of the sizing roller 32. The protective film reaches the third guide roller 53 together with the shaping roller under the action of the protective film winding mechanism 42 after rotating, and the protective film continuously moves forward to the protective film winding mechanism 42 and completes winding action after rotating around the third guide roller 53 for a certain angle. After the base material leaves the shaping roller and is conveyed with the composite pole piece for a certain distance, the base material is separated from the composite pole piece under the action of the base material winding mechanism 22 to reach the fourth guide roller 54, and the base material continuously moves forward to the protective film winding mechanism 42 and completes winding action after rotating around the fourth guide roller 54 for a certain angle.

In some embodiments, the solid electrolyte membrane is transported from the solid electrolyte membrane unreeling mechanism to the shaping rollers by guiding rollers, the number of the guiding rollers includes but is not limited to 1, 2, 3, 4, 5 or more, and the specific number can be increased or decreased according to the actual situation, preferably 1 or 2 guiding rollers.

The substrate of the solid electrolyte membrane may be transported to the substrate take-up mechanism by guiding rollers, the number of which includes, but is not limited to, 1, 2, 3, 4, 5 or more, preferably 1 guiding roller.

The protective film is guided from the protective film winding mechanism to the shaping roller by guide rollers, the number of which includes but is not limited to 1, 2, 3, 4, 5 or more, preferably 1 or 2 guide rollers.

The protective film can be guided and conveyed to the protective film winding mechanism by guide rollers, the number of which includes but is not limited to 1, 2, 3, 4, 5 or more, preferably 1 or 2 guide rollers.

Alternatively, part or all of the guide rolls may be shared in the process of conveying the solid electrolyte membrane and the protective film to the shaping rolls.

In some embodiments, the mechanical speed of the sizing roller is 5-60 m/min, including but not limited to 5m/min, 10 m/min, 20 m/min, 30 m/min, 40 m/min, 45 m/min, 50 m/min, 60 m/min.

It can be understood that the higher the tape running speed of the whole composite pole piece preparation device is, the higher the production efficiency is, but the higher the tape running speed is, the problems of tape breakage and the like of the tape running pole piece and the solid electrolyte membrane are easily caused. The residence time of the electrode plate and the solid electrolyte membrane in the gap of the shaping roller is not particularly required, and the adjustment of the residence time without creative labor on the basis of not deviating from the inventive concept of the application is understood to fall within the protection scope of the application.

In some embodiments, the linear speeds of the first shaping roller and the second shaping roller are kept consistent, the linear speed of unreeling of the electrode pole piece unreeling mechanism and the linear speed of reeling of the composite pole piece reeling mechanism are also kept consistent, the action consistency of the whole composite pole piece rolling preparation process is improved, and the consistency of the composite pole piece is improved.

In some embodiments, the linear speeds of the first sizing roller and the second sizing roller are not uniform. The rolling effect is adjusted through a first shaping roller and a second shaping roller which are arranged at different speeds.

In some embodiments, the sizing roller is internally provided with a heating unit, the temperature of which ranges from 100-300 ℃, including but not limited to 100 ℃, 150 ℃, 200 ℃, 250 ℃, 300 ℃. Preferably 150-200 ℃.

Referring to fig. 1, fig. 1 shows a flow chart of a method for preparing a composite pole piece by using the preparation device of the composite pole piece, firstly, a solid electrolyte membrane is respectively positioned at one side or two sides of the electrode pole piece, then the electrode pole piece and the solid electrolyte membrane continuously pass through a gap between shaping rollers under the dry condition, and the composite pole piece is obtained after rolling under the action of an elastic piece. The elastic piece is used for adjusting the stress conditions of the electrode pole piece and the solid electrolyte membrane in the rolling process, so that the solid electrolyte membrane can better cover the electrode pole piece; and the transverse thickness of the electrode plate tends to be consistent after rolling.

It is understood that in the rolled composite electrode sheet, the solid electrolyte layer is composited on the electrode sheet. The solid electrolyte membrane is positioned at two sides of the electrode plate, namely, the two sides of the electrode plate are compounded with the solid electrolyte membrane through the compression roller.

In some embodiments, the elastic member is a protective film. The protective film is disposed in the gap between the shaping roller and the solid electrolyte membrane at the time of rolling. Referring to fig. 4-5, a protective film, a solid electrolyte film, an electrode plate, a solid electrolyte film and a protective film are sequentially distributed between the shaping rollers. The protective film is transported from the upstream of the shaping roller to the shaping roller, passes through a gap between the shaping roller and the solid electrolyte membrane and is rolled, and then continuously moves to the downstream of the shaping roller until being recovered. Therefore, the protective film can be repeatedly utilized, reduces the damage to the environment while saving the production and manufacturing cost, and is also beneficial to improving the production efficiency.

In some embodiments, the protective film may be recovered downstream of the sizing roller by separating the protective film from the composite pole piece.

In some embodiments, the elastic member is a glue layer that surrounds the outside of the sizing roller. Referring to fig. 5, glue layers, solid electrolyte membranes, electrode plates, solid electrolyte membranes and glue layers are sequentially distributed between the shaping rollers. The axial length of the glue layer along the shaping roller can be slightly larger than that of the shaping roller, and the glue layer rotates along with the shaping roller during rolling.

The composite process is carried out under dry conditions, which are different from the traditional wet electrode preparation method, wherein the traditional wet preparation method is used for preparing the composite electrode by firstly preparing solid electrolyte slurry, then coating the solid electrolyte slurry on an electrode plate or otherwise preparing the electrode slurry, and then coating the electrode slurry on a solid electrolyte membrane. The preparation process does not use solvent, so that the complicated drying step of the subsequent steps is avoided, and the production cost can be effectively reduced.

It is understood that the dry process refers to the preparation process of the relevant electrode plate and electrolyte membrane without adding solvent; solutions of minor amounts of liquid lubricants or other liquid additives possibly used during rolling are still within the scope of the present application.

In some embodiments, both the electrode sheet and the solid electrolyte membrane are prepared by a dry process.

In some embodiments, at least one of the electrode sheet and the solid electrolyte membrane is prepared by a dry process.

In some embodiments, both the electrode sheet and the solid electrolyte membrane are prepared by a wet process.

It will be appreciated that the electrode sheet and solid electrolyte membrane are preferably prepared under dry conditions, and thus, no solvent is required throughout the electrode preparation process.

It will be appreciated that the preparation process of the electrode sheet and the solid electrolyte membrane is independent of the preparation process of the composite electrode, i.e. if a wet process is used, the electrode sheet is subjected to the coating, baking and rolling processes.

In some embodiments, the electrode sheet is a positive electrode sheet. The positive electrode material, especially the high-nickel ternary material with higher energy density, is easy to generate unexpected side reaction with electrolyte, especially nonaqueous electrolyte, and the side reaction causes the reduction of battery performance and potential safety hazard; and the solid electrolyte layer is compounded on the surface of the positive electrode, so that the safety of the battery is improved.

The positive electrode sheet includes an active material layer and a current collector layer. When preparing the positive plate by a dry method, firstly stirring an active substance, a conductive agent and a binder to obtain a positive mixture; and (3) carrying out fibrosis treatment on the mixture to obtain a fibrosis mixture of the positive electrode, and carrying out rolling compounding on the fibrosis mixture of the positive electrode and a current collector layer to obtain the positive electrode plate. In some embodiments, the method of fiberizing includes, but is not limited to, air milling, high speed stirring, mechanical fusion, twin screw extrusion, and the like.

The positive electrode active material layer is formed of a positive electrode active material containing one or more transition metal cations, such as manganese (Mn), nickel (Ni), cobalt (Co), chromium (Cr), iron (Fe), vanadium (V), and combinations thereof. The positive electrode active material layer has a thickness of greater than or equal to about 1 μm to less than or equal to about 1,000 μm.

The positive electrode active material is one of layered oxide, spinel, and polyanion. For example, a layered oxide (e.g., a rock salt layered oxide) comprises one or more lithium-based positive electrode active materials selected from the group consisting of: liCoO ₂ (LCO)，LiNi _x Mn _y Co _1-x-y O ₂ (wherein x is more than or equal to 0 and less than or equal to 1, and y is more than or equal to 0 and less than or equal to 1), and LiNi _1-x-y Co _x Al _y O ₂ (wherein x is more than or equal to 0 and less than or equal to 1, and y is more than or equal to 0 and less than or equal to 1), and LiNi _x Mn _1-x O ₂ (wherein 0.ltoreq.x.ltoreq.1), and Li _1+x MO ₂ (wherein M is one of Mn, ni, co and Al and 0.ltoreq.x.ltoreq.1). The spinel comprises one or more lithium-based positive electrode active materials selected from the group consisting of: liMn ₂ O ₄ (LMO) and LiNi _x Mn _1.5 O ₄ . Olivine-type positive electrode active material LiMPO containing one or more lithium-based positive electrode active materials ₄ (wherein M is at least one of Fe, ni, co and Mn). The polyanionic cation comprises, for example, a phosphate such as LiV ₂ (PO ₄ ) ₃ And/or silicates such as life io ₄ 。

In some embodiments, one or more lithium-based positive electrode active materials may optionally be coated (e.g., by LiNbO ₃ And/or Al ₂ O ₃ ) And/or may be doped (e.g., by magnesium (Mg)). Further, in certain embodiments, one or more lithium-based positive electrode active materials may optionally be mixed with one or more conductive materials that provide an electron conduction path and/or at least one polymeric binder material that improves the structural integrity of the positive electrode. For example, the positive electrode active material layer may contain greater than or equal to about 30 wt% to less than or equal to about 9 9 wt% of one or more lithium-based positive electrode active materials; greater than or equal to about 0 wt% to less than or equal to about 30 wt% of a conductive material; and greater than or equal to about 0 wt% to less than or equal to about 20 wt% of a binder.

In some embodiments, the binder comprises Polytetrafluoroethylene (PTFE), sodium carboxymethyl cellulose (CMC), styrene-butadiene rubber (SBR), polyvinylidene fluoride (PVDF), nitrile rubber (NBR), styrene-ethylene-butylene-styrene copolymer (SEBS), styrene-butadiene-styrene copolymer (SBS), lithium polyacrylate (LiPAA), sodium polyacrylate (NaPAA), sodium alginate, lithium alginate, and combinations thereof.

In some embodiments, the conductive material may include a carbon-based material, powdered nickel or other metal particles, or a conductive polymer. Carbon-based materials may include, for example, carbon black, graphite, acetylene black (e.g., KETCHENTM black or denktatm black), carbon fibers and particles of nanotubes, graphene, and the like. Examples of the conductive polymer include polyaniline, polythiophene, polyacetylene, polypyrrole, and the like.

It is to be understood that the above examples of positive electrode active materials, binders, and conductive materials are merely illustrative, and any known positive electrode active materials, binders, and conductive materials can be used in the present application without departing from the inventive concepts of the present application. And the addition of known additives based on actual use needs is also considered to be within the scope of the present application.

In some embodiments, both the front and back sides of the current collector layer comprise an active material layer.

In some embodiments, the current collector layer may employ a metal foil or a composite current collector.

For example, aluminum foil may be used as the metal foil.

The composite current collector may include a polymeric material base layer and a metal layer formed on at least one surface of the polymeric material base material.

Studies have shown that wet coating is often used in the conventional art, but since the positive electrode active slurry is a water-based slurry, protrusions are often generated at the edges of the active material layer during drying due to fluidity and surface tension of the slurry. Meanwhile, when the positive electrode active material layer is rolled, the edges of the active material layer are cracked directly due to rolling stress, so that the positive electrode active material layer is cracked, and finally the performance of the battery is influenced. In addition, the problems of expansion, too fast performance decay and the like occur in the long-time circulation process of the battery due to the fact that the moisture content is too high in wet coating.

In some embodiments, the electrode sheet is a negative electrode sheet.

The negative electrode tab is formed of a lithium host material (e.g., a negative electrode active material) that can be used as a negative electrode terminal of a lithium ion battery. In various aspects, the negative electrode tab may be defined by a plurality of negative electrode active material particles. Such anode active material particles may be disposed in one or more layers so as to define the three-dimensional structure of the anode. In certain embodiments, the negative electrode may also include an electrolyte 50, such as a plurality of electrolyte particles (not shown).

In some embodiments, the negative electrode tab may be a negative electrode active material comprising lithium, including, for example, lithium metal and/or lithium alloy.

The negative electrode sheet may be a silicon-based negative active material comprising, for example, a silicon alloy, silicon oxide, or a combination thereof, which may also be mixed with graphite in some cases.

The negative electrode sheet may be a carbonaceous-based negative electrode active material comprising one or more of graphite, graphene, carbon Nanotubes (CNT), and combinations thereof.

The negative electrode sheet may also include one or more negative active materials that accept lithium, such as lithium titanium oxide (Li ₄ Ti ₅ O ₁₂ ) One or more transition metals (e.g., tin (Sn)), one or more metal oxides (e.g., vanadium oxide (V) ₂ O ₅ ) Tin oxide (SnO), titanium dioxide (TiO) ₂ ) Titanium niobium oxide (TixNbyOz, where 0.ltoreq.x.ltoreq.2, 0.ltoreq.y.ltoreq.24, and 0.ltoreq.z.ltoreq.64), metal alloys (such as copper-tin alloys (Cu) ₆ Sn ₅ ) And one or more metal sulfides (such as sulfur)Iron (FeS)).

Alternatively, the negative active material in the negative electrode sheet may be doped with one or more conductive materials that provide an electron conduction path and/or at least one polymeric binder material that improves the structural integrity of the negative electrode. For example, the anode active material may be doped with a binder such as: poly (tetrafluoroethylene) (PTFE), sodium carboxymethylcellulose (CMC), styrene-butadiene rubber (SBR), polyvinylidene fluoride (PVDF), nitrile-butadiene rubber (NBR), styrene-butylene-styrene copolymer (SEBS), styrene-butadiene-styrene copolymer (SBS), lithium polyacrylate (LiPAA), sodium polyacrylate (NaPAA), sodium alginate, lithium alginate, and combinations thereof. The conductive material may include carbon-based materials, powdered nickel or other metallic particles, or conductive polymers. The carbon-based material may include, for example, particles of carbon black, graphite, superP, acetylene black (such as KETCHENTM black or denktatm black), carbon fibers and nanotubes, graphene, and the like. Examples of the conductive polymer include polyaniline, polythiophene, polyacetylene, polypyrrole, poly (3, 4-ethylenedioxythiophene) polysulfstyrene, and the like.

The negative electrode sheet may include greater than or equal to about 50 wt% to less than or equal to about 99 wt% of a negative electrode active material, alternatively greater than or equal to about 0 wt% to less than or equal to about 60 wt% of a solid state electrolyte, alternatively greater than or equal to about 0 wt% to less than or equal to about 15 wt% of a conductive material, and alternatively greater than or equal to about 0 wt% to less than or equal to about 10 wt% of a binder.

Dry preparation as mentioned in the background art, the electrode sheet is chamfered for smooth rolling process due to the problems of high strength and poor deformation resistance of the conventional sizing roller, so as to form a structure with thick middle and thin two ends. As shown in fig. 2, when the solid electrolyte membrane 2 is attached to the electrode sheet 1 due to the non-uniformity of the lateral thickness of the electrode sheet 1, the edge region of the electrode sheet 1 remains in a separated state from the solid electrolyte membrane. When the rolling equipment carries out rolling lamination on the electrode pole piece 1 and the solid electrolyte membrane 2, the electrode pole piece 1 and the solid electrolyte membrane 2 are difficult to be tightly compounded, namely ineffective compounding is caused by different rolling forces of a steel roller on the middle area and the edge area of the electrode pole piece 1, and meanwhile, the transverse compaction density of the composite pole piece is inconsistent, and the consistency of the composite pole piece is poor. The electrode plate is severely broken, so that the safety performance and quality of the lithium ion battery are greatly affected.

According to the preparation method, the solid electrolyte membrane can better cover the electrode pole piece by utilizing the buffer provided by the elastic piece when the shaping roller is rolled; meanwhile, in the rolling process of the shaping roller, the stress of the middle area of the electrode plate is larger than that of the edge area due to the fact that the middle thickness of the electrode plate is thicker, and the transverse thickness of the electrode plate tends to be consistent after rolling, as shown in fig. 3, so that the electrode plate is effectively compounded. The method avoids the adverse effect on the rolling compounding process caused by the phenomena of thick middle and thin two ends of the electrode pole piece 1 to a certain extent, protects the electrode pole piece 2 from being crushed, and simultaneously can ensure better combination between the active substance layer in the electrode pole piece 1 and the solid electrolyte membrane 2. In addition, the electrode plate 1 and the solid electrolyte membrane 2 can be uniformly pressed under the stress in the rolling process of the shaping roller, so that the compaction density of the composite electrode plate is improved, the consistency of the thickness of the composite electrode plate is ensured, the phenomena of thick middle and thin two ends of the electrode plate 1 are weakened, the continuous rolling quality is improved, and the method can be used for mass production.

In some embodiments, the solid electrolyte membrane includes a solid electrolyte and a binder.

When preparing the solid electrolyte membrane, firstly, stirring and mixing the solid electrolyte and the binder, and carrying out fibrosis treatment on the mixture to obtain a fibrosis solid electrolyte mixture, wherein the fibrosis solid electrolyte mixture is pressed by rolling to obtain the solid electrolyte membrane.

In some embodiments, the solid state electrolyte is an inorganic solid state electrolyte including one or more of an oxide solid state electrolyte, a sulfide solid state electrolyte, a halide solid state electrolyte, a hydride solid state electrolyte, a boride solid state electrolyte, and a nitride solid state electrolyte.

The oxide solid electrolyte comprises one or more garnet ceramics, LISICON-type oxides, NASICON-type oxides andperovskite type ceramics. For example, one or more garnet ceramics include, but are not limited to, li _6.5 La ₃ Zr _1.75 Te _0.25 O ₁₂ 、Li ₇ La ₃ Zr ₂ O ₁₂ 、Li _6.2 Ga _0.3 La _2.95 Rb _0.05 Zr ₂ O ₁₂ 、Li _6.85 La _2.9 Ca _0.1 Zr _1.75 Nb _0.25 O ₁₂ 、Li _6.25 Al _0.25 La ₃ Zr ₂ O ₁₂ 、Li _6.75 La ₃ Zr _1.75 Nb _0.25 O ₁₂ One or more of the following. One or more LISICON-type oxides include, but are not limited to, li ₁₄ Zn(GeO ₄ ) ₄ 、Li _3+x (P _1−x Si _x )O ₄ (wherein 0<x<1）、Li _3+x Ge _x V _1-x O ₄ (wherein 0<x<1) One or more of the following. One or more NASICON type oxides can be selected from LiMM ʹ (PO ₄ ) ₃ Definition, wherein M and M ʹ are independently selected from Al, ge, ti, sn, hf, zr and La. For example, in certain variations, the one or more NASICON-type oxides include, but are not limited to, li _1+x Al _x Ge _2-x (PO ₄ ) ₃ (LAGP) (wherein 0.ltoreq.x.ltoreq.2), li _1+x Al _x Ti _2-x (PO ₄ ) ₃ (LATP) (where 0.ltoreq.x.ltoreq.2), li ₁₊ _x Y _x Zr _2-x (PO ₄ ) ₃ (LYZP) (wherein 0.ltoreq.x.ltoreq.2), li _1.3 Al _0.3 Ti _1.7 (PO ₄ ) ₃ 、LiTi ₂ (PO ₄ ) ₃ 、LiGeTi(PO ₄ ) ₃ 、LiGe ₂ (PO ₄ ) ₃ 、LiHf ₂ (PO ₄ ) ₃ One or more of the following. One or more perovskite-type ceramics including, but not limited to, li _3.3 La _0.53 TiO ₃ 、LiSr _1.65 Zr _1.3 Ta _1.7 O ₉ 、Li _2x-y Sr _1-x Ta _y Zr _1-y O ₃ (wherein x=0.75 y and 0.60<y<0.75）、Li _3/8 Sr _7/16 Nb _3/4 Zr _1/4 O ₃ 、Li _3x La _(2/3-x) TiO ₃ (wherein 0<x<0.25 One or more of the following).

Sulfide solid state electrolytes include, but are not limited to, li ₂ S-P ₂ S ₅ 、Li ₂ S-P ₂ S ₅ -MS _x (wherein M is Si, ge and Sn and 0.ltoreq.x.ltoreq.2), li _3.4 Si _0.4 P _0.6 S ₄ 、Li ₁₀ GeP ₂ S _11.7 O _0.3 、Li _9.6 P ₃ S ₁₂ 、Li ₇ P ₃ S ₁₁ 、Li ₉ P ₃ S ₉ O ₃ 、Li _10.35 Si _1.35 P _1.65 S ₁₂ 、Li _9.81 Sn _0.81 P _2.19 S ₁₂ 、Li ₁₀ (Si _0.5 Ge _0.5 )P ₂ S ₁₂ 、Li(Ge _0.5 Sn _0.5 )P ₂ S ₁₂ 、Li(Si _0.5 Sn _0.5 )PsS ₁₂ 、Li ₁₀ GeP ₂ S ₁₂ （LGPS）、Li ₆ PS ₅ X (wherein X is Cl, br or I), li ₇ P ₂ S ₈ I、Li _10.35 Ge _1.35 P _1.65 S ₁₂ 、Li _3.25 Ge _0.25 P _0.75 S ₄ 、Li ₁₀ SnP ₂ S ₁₂ 、Li ₁₀ SiP ₂ S ₁₂ 、Li _9.54 Si _1.74 P _1.44 S _11.7 C _l0.3 、 _(1-x) P ₂ S _5-x Li ₂ S (wherein 0.5.ltoreq.x.ltoreq.0.7).

The halide solid state electrolyte includes, but is not limited to, li ₂ CdC _l4 、Li ₂ MgC _l4 、Li ₂ Cd _I4 、Li ₂ ZnI ₄ 、Li ₃ OCl、LiI、Li ₅ ZnI ₄ 、Li ₃ OCl _1-x Br _x (wherein 0<x<1) One or more of (a) and (b).

Boride solid state electrolytes include, but are not limited to, li ₂ B ₄ O ₇ 、Li ₂ O-(B ₂ O ₃ )-(P ₂ O ₅ ) One or more of (a) and (b).

Nitride solid state electrolytes including but not limited to Li ₃ N、Li ₇ PN ₄ 、LiSi ₂ N ₃ One or more of LiPON.

The hydride solid state electrolyte includes, but is not limited to, li ₃ AlH ₆ 、LiBH ₄ 、LiBH ₄ -LiX (wherein X is one of Cl, br and I), liNH ₂ 、Li ₂ NH、LiBH ₄ -LiNH ₂ One or more of (a) and (b).

In some embodiments, the inorganic solid state electrolyte may be one or more metal oxide particles or lithium-containing compounds, including but not limited to Al ₂ O ₃ 、SiO ₂ 、TiO ₂ 、LiNbO ₃ 、Li ₄ Ti ₅ O ₄ 、Li ₃ PO ₄ One or more of the following.

In some embodiments, the solid state electrolyte further comprises a portion of a polymer solid state electrolyte.

A composite solid electrolyte composed of a polymer solid electrolyte and an inorganic solid electrolyte. In the embodiment of the application, the mass ratio of the inorganic solid electrolyte and the polymer solid electrolyte in the composite solid electrolyte is not particularly required, and a user can design according to actual needs. Wherein, the polymer solid electrolyte can be at least one of polyvinyl chloride (PVC), polyacrylonitrile (PAN), polymethyl methacrylate (PMMA) and polyethylene oxide (PEO).

In some embodiments, the lithium salt is included in the polymer solid electrolyte.

In some embodiments, the lithium salt includes, but is not limited to, lithium hexafluorophosphate (LiPF) ₆ ) The method comprises the steps of carrying out a first treatment on the surface of the Lithium perchlorate (LiClO) ₄ ) Lithium tetrachloroaluminate (LiAlCl) ₄ ) Lithium iodide (LiI), lithium bromide (LiBr), lithium thiocyanate (LiSCN), lithium tetrafluoroborate (LiBF) ₄ ) Lithium difluorooxalato borate (LiBF) ₂ (C ₂ O ₄ ) (LiODFB), lithium tetraphenylborate (LiB (C) ₆ H ₅ ) ₄ ) Lithium bis (oxalato) borate (LiB (C) ₂ O ₄ ) ₂ ) Lithium tetrafluorooxalate phosphate (LiPF) ₄ (C ₂ O ₄ ) (LiFeP), lithium nitrate (LiNO) ₃ ) Lithium hexafluoroarsenate (LiAsF) ₆ ) Lithium triflate (LiCF) ₃ SO ₃ ) Lithium bis (trifluoromethanesulfonyl imide) (LITFSI) (LiN (CF) ₃ SO ₂ ) ₂ ) Lithium bis (fluorosulfonyl imide) (LiN (FSO) ₂ ) ₂ ) (LIFSI) and combinations thereof. In certain variations, the lithium salt is selected from lithium hexafluorophosphate (LiPF ₆ ) Lithium bis (trifluoromethanesulfonyl imide) (LiTFSI) (LiN (CF) ₃ SO ₂ ) ₂ ) Lithium bis (fluorosulfonyl imide) (LiN (FSO) ₂ ) ₂ ) (LiFSI), lithium fluoroalkylphosphonate (LiFAP), lithium phosphate (Li) ₃ PO ₄ ) One or more of the following.

It is to be understood that the above-mentioned terms including oxide solid electrolyte, sulfide solid electrolyte, halide solid electrolyte, hydride solid electrolyte, nitride solid electrolyte, polymer solid electrolyte, etc. are all known in the art, and the above-mentioned materials are merely illustrative examples, and not limiting the scope of protection, and any known solid electrolyte type can be used in the present application without departing from the inventive concept of the present application.

In some embodiments, the solid electrolyte membrane is formed separately, i.e., the solid electrolyte membrane is formed without the aid of a substrate and the membrane remains intact.

In some embodiments, the side of the solid electrolyte membrane remote from the electrode pads is covered with a substrate having a lower binding force to the solid electrolyte membrane than to the electrode pads. After rolling, at least a portion of the solid electrolyte is transferred to the electrode and separated from the substrate.

The type of the base material is not particularly limited, and any known material which has a certain supporting effect, can be more beneficial to film formation of electrolyte materials and can be separated from a solid electrolyte membrane after rolling can be used in the application on the basis of not departing from the inventive concept of the application; by way of illustrative example only, and not by way of any limitation of the scope of protection, the substrate is selected from one or more of silicone oil release film, fluorine release film, PET film, PP film, PE/PP film, PP/PE/PP film, PE/PP/PE film, non-silicon release film.

The application also provides a composite pole piece, which is prepared according to the preparation method of the composite pole piece.

The application also provides a lithium ion battery, which comprises the composite pole piece.

In some embodiments, the electrode sheet and solid electrolyte membrane may also be purchased.

Embodiments of the present invention will be described more specifically below by way of examples. However, embodiments of the present invention are not limited to these examples only.

Example 1

1. Preparation of positive electrode sheet

Lithium manganate is selected as an anode active material, ketjen black is selected as a conductive agent and PTFE is selected as a binder, and the materials are mixed and stirred by a high-speed stirrer to obtain an anode mixture. And then subjecting the mixture to a fiberization treatment by means of an air-jet mill to obtain a fiberization mixture of the positive electrode, namely a positive electrode active material layer. And rolling and compounding the positive electrode active material layer and a current collector to obtain the positive electrode plate.

2. Preparation of solid electrolyte film

LATP is selected as a solid electrolyte, polytetrafluoroethylene is selected as a binder, and the solid electrolyte mixture is obtained by mixing and stirring the substances by using a high-speed stirrer. And then carrying out fiberization treatment on the mixture by an air flow mill to obtain a fiberized solid electrolyte mixture, and pressing the fiberized solid electrolyte mixture by a roller to obtain the solid electrolyte membrane.

3. Preparing a composite positive plate

The positive electrode sheet and the two layers of solid electrolyte films are compounded by the compound electrode sheet preparation device provided with the protective film as shown in fig. 4, so that the solid electrolyte films are simultaneously compounded on the positive electrode active material layers on the two sides of the positive electrode sheet. Wherein the protective film is PE-based non-woven fabric.

The solid electrolyte membrane starts from the solid electrolyte membrane unreeling mechanism 21 and passes through the first guide roller 51 to reach the shaping roller; the protective film starts from the protective film unreeling mechanism and passes through the second guide roller 52 to reach the shaping roller; the first guide roller 51 is located on the side of the second guide roller 52 remote from the shaping roller. The solid electrolyte membrane and the protective film are contacted with the positive pole piece after rotating along with the shaping roller, and pass through a gap between the first shaping roller and the second shaping roller, more particularly pass through a gap between the shaping roller and the positive pole piece. And then rolling down the positive electrode plate by the first shaping roller and the second shaping roller to complete the compounding of the positive electrode plate and the two layers of solid electrolyte membranes. The composite pole piece advances to the composite pole piece winding mechanism 12 under the action of the composite pole piece winding mechanism 12, and is received and wound by the composite pole piece winding mechanism 12, so that the composite pole piece with the solid electrolyte membrane composited on both sides of the positive pole piece is obtained.

After the protective film and the base material leave from the gap between the first shaping roller 31 and the second shaping roller 32, the protective film and the base material are separated from the composite pole piece and rotate for a certain angle along with the first shaping roller 31 or the second shaping roller 32, and the protective film is received and wound by a protective film winding mechanism through a third guide roller 53; the substrate is received and wound by the solid electrolyte membrane winding mechanism through a fourth guide roller 54; the third guide roller 53 is located on the side of the fourth guide roller 52 close to the shaping roller.

Detecting the thickness of the middle area of the composite pole piece to be 160 mu m, detecting the thickness of the edge area to be 160 mu m, and observing the surface of the composite pole piece to be free from cracks under naked eyes, so as to meet the use standard of the composite pole piece; the protective film is not significantly deformed.

Example 2

1. Preparation of positive electrode sheet

2. Preparation of solid electrolyte film

LGPS is selected as solid electrolyte, polytetrafluoroethylene is selected as binder and LiPF ₆ As the lithium salt, the above materials were mixed and stirred using a high-speed stirrer to obtain a solid electrolyte mixture. And then carrying out fiberization treatment on the mixture by an air flow mill to obtain a fiberized solid electrolyte mixture, and pressing the fiberized solid electrolyte mixture by a roller to obtain the solid electrolyte membrane.

3. Preparing a composite positive plate

The positive electrode plate and the two layers of solid electrolyte membranes are compounded through the compound electrode plate preparation device provided with the protective film, so that the solid electrolyte membranes are simultaneously compounded on the positive electrode active material layers on the two sides of the positive electrode plate. Wherein the protective film is PE-based non-woven fabric,

the solid electrolyte membrane starts from the solid electrolyte membrane unreeling mechanism, passes through the first guide roller and the second guide roller, and then reaches the shaping roller; the protective film starts from the protective film unreeling mechanism and passes through the second guide roller 52 to reach the shaping roller; the first guide roller 51 is located on the side of the second guide roller 52 remote from the shaping roller. The solid electrolyte membrane and the protective film are contacted with the positive pole piece after rotating along with the shaping roller, and pass through a gap between the first shaping roller and the second shaping roller, more particularly pass through a gap between the shaping roller and the positive pole piece. And then rolling down the positive electrode plate by the first shaping roller and the second shaping roller to complete the compounding of the positive electrode plate and the two layers of solid electrolyte membranes. The composite pole piece advances to the composite pole piece winding mechanism under the action of the composite pole piece winding mechanism, and is received and wound by the composite pole piece winding mechanism 12, so that the composite pole piece with the solid electrolyte membrane composited on both sides of the positive pole piece is obtained.

After the protective film and the base material leave from the gap between the first shaping roller and the second shaping roller, the protective film and the base material are separated from the composite pole piece and rotate for a certain angle along with the first shaping roller or the second shaping roller, then the protective film and the base material are respectively conveyed to the third guide roller under the action of the protective film winding mechanism and the base material winding mechanism 22, and the protective film and the base material are separated after rotating for a certain angle around the third guide roller, the protective film is received and wound by the protective film winding mechanism 42, and the base material is received and wound by the base material winding mechanism 22.

Detecting the thickness of the middle area of the composite pole piece to be 190 mu m, detecting the thickness of the edge area to be 190 mu m, and observing the surface of the composite pole piece to be free from cracks under naked eyes, so as to meet the use standard of the composite pole piece; the protective film is not significantly deformed.

Example 3

1. Preparation of positive electrode sheet

2. Preparation of solid electrolyte film

3. Preparing a composite positive plate

The positive electrode plate and the two layers of solid electrolyte membranes are compounded through a roller press provided with an adhesive layer as shown in fig. 5, so that the solid electrolyte membranes are simultaneously compounded on the positive electrode active material layers on the two sides of the positive electrode plate.

The solid electrolyte membrane starts from the solid electrolyte membrane unreeling mechanism and reaches the shaping roller after passing through the first guide roller; the solid electrolyte membrane is contacted with the positive electrode plate after rotating along with the shaping roller, and the composite electrode plate advances to the composite electrode plate winding mechanism 12 under the action of the composite electrode plate winding mechanism 12 through a gap between the first shaping roller and the second shaping roller, and is received and wound by the composite electrode plate winding mechanism 12, so that the composite electrode plate with the solid electrolyte membrane at both sides of the positive electrode plate is obtained. After the substrate leaves the gap between the first shaping roller 31 and the second shaping roller 32, the substrate rotates with the first shaping roller 31 or the second shaping roller 32 to a certain angle, and then the substrate is conveyed to the third guide roller 53 under the action of the substrate winding mechanism 22, and is received and wound by the substrate winding mechanism 22 located downstream of the third guide roller 53.

Detecting the thickness of the middle area of the composite pole piece to be 160 mu m, detecting the thickness of the edge area to be 160 mu m, and observing the surface of the composite pole piece to be free from cracks under naked eyes, so as to meet the use standard of the composite pole piece; the appearance of the glue layer is kept good.

Comparative example 1

Compounding the positive electrode plate and two layers of solid electrolyte membranes by adopting a roller press as shown in fig. 6, so that the solid electrolyte membranes are simultaneously compounded on the positive electrode active material layers on two sides of the positive electrode plate; the roll press shown in fig. 6 differs from the roll press shown in fig. 5 in that the outside of the setting roll has no adhesive layer. Methods of preparing the positive electrode sheet, preparing the solid electrolyte membrane, and preparing the composite positive electrode sheet were all in accordance with example 3.

Interlayer separation phenomenon exists at the edge of the composite pole piece, and microcracks exist at the edge.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples illustrate only a few embodiments of the invention, which are described in detail and are not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.

Claims

1. The preparation method of the composite pole piece is characterized by comprising the following steps:

conveying the solid electrolyte membrane through a solid electrolyte membrane unreeling mechanism positioned at the side edge of the electrode pole piece unreeling mechanism, so that the solid electrolyte membrane passes through a gap between a shaping roller and the electrode pole piece; and

the solid electrolyte membrane positioned on the side surface of the electrode plate is pressed on the electrode plate by a shaping roller to obtain a composite electrode plate;

an elastic piece is arranged between the shaping roller and the solid electrolyte membrane on the electrode pole piece; the yield limit of the elastic member satisfies: when the solid electrolyte membrane and the electrode pole piece pass through a gap between the shaping rollers, the solid electrolyte membrane and the electrode pole piece are subjected to plastic deformation, and the elastic piece is subjected to elastic deformation;

the electrode plate comprises a positive electrode plate and/or a negative electrode plate.

2. The method of claim 1, wherein the elastic member is a protective film that is transported through a gap between the shaping roller and the solid electrolyte membrane.

3. The method according to claim 1, wherein the elastic member is a glue layer which is circumferentially covered outside the sizing roller.

4. The method according to claim 1, wherein the solid electrolyte membrane on both sides of the electrode sheet is pressed onto the electrode sheet by a shaping roller to obtain the composite sheet.

5. The method according to any one of claims 1-4, further comprising: separating the base material covered on the solid electrolyte membrane from the composite pole piece.

6. The method of claim 2, wherein the protective film is a polymeric film or a nonwoven fabric.

7. A method according to claim 3, wherein the glue layer is plastic, rubber, or silicone.

8. The method of claim 1, wherein the method of preparing further comprises:

the composite pole piece is received by a composite pole piece winding mechanism at the downstream of the shaping roller;

receiving a substrate between the shaping roller and the composite pole piece winding mechanism through a substrate winding mechanism;

9. The method of claim 8, wherein the method of preparing further comprises:

conveying the elastic piece through a protective film unreeling mechanism; the protective film unreeling mechanism is positioned between the solid electrolyte film unreeling mechanism and the shaping roller; and

10. The composite pole piece is characterized in that the composite pole piece is prepared by the method according to any one of claims 1-9.

11. A lithium ion battery, characterized by comprising the composite pole piece prepared by the method of any one of claims 1-9.

12. A composite pole piece preparation device for preparing a composite pole piece, the device comprising:

13. The apparatus of claim 12, wherein the apparatus further comprises:

the composite pole piece winding mechanism is positioned at the downstream of the shaping roller and is used for receiving the composite pole piece; and

14. The apparatus of claim 13, wherein the apparatus further comprises:

the protective film unreeling mechanism is positioned between the solid electrolyte film unreeling mechanism and the shaping roller and is used for conveying the elastic piece; and

the elastic piece is a protective film.

15. The device according to claim 12 or 13, characterized in that the elastic element is a glue layer which is circumferentially covered outside the sizing roller.