Composite electrode sheet and preparation method and preparation device therefor, and lithium ion battery

Abstract

A preparation method for a composite electrode sheet, a composite electrode sheet preparation device for preparing the composite electrode sheet, and a lithium ion battery comprising the composite electrode sheet. During a dry rolling process, an electrode sheet is conveyed by means of an electrode sheet unwinding mechanism, a solid electrolyte membrane is conveyed by means of a solid electrolyte membrane unwinding mechanism, and then the solid electrolyte membrane located on a side face of the electrode sheet is rolled on the electrode sheet by using an elastic member arranged between a shaping roller and the solid electrolyte membrane, so as to obtain the composite electrode sheet.

Description

Composite pole piece, preparation method and device thereof, and lithium-ion battery

[0001] Related applications

[0002] This application claims priority to Chinese patent application No. 2023107610426 filed on June 27, 2023, entitled “METHOD FOR PREPARING COMPOSITE ELECTRODE PIECES, PREPARATION DEVICE AND LITHIUM-ION BATTERY”; Chinese patent application No. 202321841019X filed on July 13, 2023, entitled “DEVICE FOR PREPARING COMPOSITE ELECTRODE PIECES AND COMPOSITE ELECTRODE PIECES”; and Chinese patent application No. 202310847662 filed on July 12, 2023, entitled “Claim priority to Chinese patent application No. 2023107610426 filed on June 27, 2023, entitled “Claim priority to Chinese patent application No. 2023107610426 filed on July 13, 2023, entitled “Claim priority to Chinese patent application No. 202310847662 filed on July 12, 2023, entitled “Claim priority to Chinese patent application No. 1. Priority of the Chinese patent application entitled “Composite pole piece and its preparation method, lithium-ion battery”; priority of the Chinese patent application No. 2023108596479 filed on July 13, 2023, entitled “Composite pole piece and its preparation method, lithium-ion battery”; priority of the Chinese patent application No. 202321843129X filed on July 13, 2023, entitled “Composite pole piece and its preparation device, lithium-ion battery”; priority of the Chinese patent application No. 202321843129X filed on July 13, 2023, entitled “Composite pole piece and its preparation device, lithium-ion battery”; Priority to the Chinese patent application No. 2023109593675 filed on August 1, 2023, entitled “Composite pole piece and its preparation method, lithium-ion battery”; Priority to the Chinese patent application No. 2023109318786 filed on July 27, 2023, entitled “Composite pole piece and its preparation method, lithium-ion battery”; Priority to the Chinese patent application No. 2023109596781 filed on August 1, 2023, entitled “Composite pole piece and its preparation method, lithium-ion battery” The application claims priority to the Chinese patent application entitled “Method for preparing composite pole piece, composite pole piece and solid-state battery” filed on July 27, 2023, with application number 2023109316367; and the application claims priority to the Chinese patent application entitled “Composite pole piece and preparation method thereof, lithium-ion battery” filed on July 5, 2023, with application number 2023108177121; the entire text of which is hereby incorporated by reference. Technical Field

[0003] The present application relates to the field of battery technology, and in particular to a composite pole piece and a method for preparing the composite pole piece, a device for preparing the composite pole piece, and a lithium-ion battery comprising the composite pole piece. Background Art

[0004] Lithium-ion batteries are currently the dominant energy storage device in the market, boasting broad application prospects. With the continuous emergence of new technologies, the requirements for battery performance are becoming increasingly stringent. Traditional liquid batteries, which use non-aqueous electrolytes as their electrolyte system, present numerous safety concerns, such as the flammability and explosiveness of conventional electrolyte materials, and the tendency of cathode materials, especially high-energy-density, high-nickel ternary materials, to undergo undesirable side reactions with the electrolyte, potentially causing battery safety issues.

[0005] In order to improve the safety performance of batteries, it is generally believed that setting a solid electrolyte layer on the electrode has a positive effect. At present, the method of composite solid electrolyte on the electrode surface is mainly to apply the solid electrolyte slurry to the electrode surface by coating. This method can be directly embedded in the current mature coating process, but it also faces many problems. For example, (1) in the drying process after coating, due to the rapid drying and volatilization of the solvent, the surface tension of the electrode plate changes rapidly, and the electrode plate is prone to curling and warping. At the same time, the rapid volatilization of the solvent causes the crystalline binder to segregate on the surface of the plate; (2) some electrolyte materials, such as sulfide solid electrolytes, are extremely sensitive to moisture. The small amount of moisture in the wet process is easy to corrode the electrolyte material; (3) some new binders have compatibility issues with solvents, and new solvents need to be developed to adapt to the new binders; (4) the wet process consumes a large amount of solvent, and the environmental treatment cost is too high.

[0006] Therefore, researchers and developers have gradually turned their attention to dry-processing to produce composite electrodes and solid electrolyte membranes to improve battery safety. Currently, methods for dry-processing electrode sheets have been reported, and the proportion of dry-process electrodes in the battery field has increased year by year.

[0007] Compared with dry electrodes, the difficulty in preparing composite electrodes containing solid electrolyte membranes through dry processes is that the interlayer bonding force between the solid electrolyte layer and the electrode layer is weak, and the mechanical strength of the composite electrode is weak; the dry roller-pressing composite of multi-layer structures has different technical characteristics from the rolling of single-layer structures; on the other hand, the bonding strength between the two layers of dry membranes still needs to be improved; therefore, it is very important to study a preparation method for dry composite electrodes with universal applicability.

[0008] In the rolling step of preparing composite pole pieces by dry process, due to the thinning treatment of the electrode pole piece edges during production, when the solid electrolyte membrane and the electrode pole piece are composited, it is easy to cause poor composite effect of the electrode pole piece and the solid electrolyte membrane, inconsistent lateral compaction density of the composite pole piece, and poor lateral thickness consistency, which will have a great impact on the safety performance and quality of lithium-ion batteries.

[0009] Moreover, in the rolling step of preparing composite electrodes by the dry process, due to the limitations of the rigidity of the roller press equipment and the deformation resistance of the roller, the roller is easily subjected to force and flexural deformation during rolling, which will cause the positive / negative electrode sheets to be thick in the middle and thin at both ends after rolling. Furthermore, when the positive / negative electrode sheets are rolled and composited with the solid electrolyte membrane, it is easy to cause poor composite effect of the electrode sheets and the solid electrolyte membrane, inconsistent lateral compaction density of the composite electrode sheets, and poor lateral thickness consistency, which will have a great impact on the safety performance and quality of lithium-ion batteries.

[0010] In addition, the use of similar lamination techniques to form and manufacture lithium-ion batteries with electrodes and solid electrolyte membranes in laboratory pilot trials is known. However, continuous production of composite electrodes before cutting remains unattainable, posing a significant technical challenge in designing and improving existing equipment to manufacture composite electrodes.

[0011] Summary of the Invention

[0012] Based on this, on the one hand, the present application relates to a method for preparing a composite electrode sheet, including: conveying the electrode sheet through an electrode sheet unwinding mechanism so that the electrode sheet passes through the gap in the middle of the shaping roller assembly; conveying the solid electrolyte membrane through a solid electrolyte membrane unwinding mechanism located on the side of the electrode sheet unwinding mechanism so that the solid electrolyte membrane passes through the gap between the shaping roller assembly and the electrode sheet; and composite the electrode sheet and the solid electrolyte membrane through the shaping roller assembly to obtain a composite electrode sheet; wherein, an elastic member is arranged between the shaping roller assembly and the solid electrolyte membrane rolled on the electrode sheet.

[0013] In some embodiments, the preparation method of the present application further includes: heating the electrode sheet, or the solid electrolyte membrane, or both the electrode sheet and the solid electrolyte membrane using a heating mechanism; the heating mechanism is located between the electrode sheet unwinding mechanism and the sizing roller assembly, and / or the heating mechanism is located within the sizing roller assembly. In some embodiments, the solid electrolyte membrane includes a first solid electrolyte membrane and a second solid electrolyte membrane, which are rolled and laminated onto both sides of the electrode sheet by the sizing roller assembly. In some embodiments, the elastic member is a protective film or adhesive layer, which is transported through the gap between the sizing roller assembly and the solid electrolyte membrane; the adhesive layer surrounds and covers the outside of the sizing roller assembly. In some embodiments, the adhesive layer is plastic, rubber, or silicone; and the protective film is a polymer film or non-woven fabric. In some embodiments, the sizing roller assembly includes a first sizing roller assembly and a second sizing roller assembly, and an elastic member is disposed between at least one of the first sizing roller assembly and the second sizing roller assembly and the solid electrolyte membrane rolled onto the electrode sheet. In some embodiments, the sizing roller assembly includes a first sizing roller assembly and a second sizing roller assembly, wherein at least one of the first sizing roller assembly and the second sizing roller assembly, together with an elastic member, forms an elastic rolling assembly. In some embodiments, the elastic rolling assembly includes an elastic roller, which is used to contact and roll the solid electrolyte membrane. The elastic roller includes a rigid roller and an elastic member, with the elastic member covering the outer side of the rigid roller. In some embodiments, the elastic rolling assembly includes a sizing steel roller and an elastic roller having a lower hardness than the sizing steel roller.

[0014] In some embodiments, the preparation method of the present application includes: conveying the electrode sheet through an electrode sheet unwinding mechanism so that the electrode sheet passes through the gap between a heating mechanism and a sizing roller assembly; preheating the electrode sheet through the heating mechanism to produce a preheated sheet; and roll-combining the preheated sheet and a solid electrolyte membrane through the sizing roller assembly to produce a composite electrode sheet. In some embodiments, the heating mechanism includes a first heating mechanism and a second heating mechanism; the sizing roller assembly includes a first sizing roller assembly and a second sizing roller assembly; the first heating mechanism is located between the electrode sheet unwinding mechanism and the first sizing roller assembly, and the second heating mechanism is located between the first sizing roller assembly and the second sizing roller assembly. In some embodiments, the preparation method of the present application includes: conveying the electrode sheet through an electrode sheet unwinding mechanism so that the electrode sheet passes through a first heating mechanism; conveying the first solid electrolyte membrane through a first solid electrolyte membrane unwinding mechanism located on one side of the electrode sheet unwinding mechanism so that the first solid electrolyte membrane passes through a first heating mechanism; heating the electrode sheet and the first solid electrolyte membrane through the first heating mechanism; compounding the heated electrode sheet and the first solid electrolyte membrane through a first shaping roller assembly to obtain a composite membrane sheet; conveying the second solid electrolyte membrane through a second solid electrolyte membrane unwinding mechanism located on the other side of the electrode sheet unwinding mechanism so that the second solid electrolyte membrane passes through a second heating mechanism; heating the composite membrane sheet and the second solid electrolyte membrane through the second heating mechanism; and compounding the heated composite membrane sheet and the second solid electrolyte membrane through a second shaping roller assembly to obtain a composite sheet. In some embodiments, the heating mechanism includes a first heating mechanism and a second heating mechanism; the preparation method includes: conveying the electrode sheet through an electrode sheet unwinding mechanism so that the electrode sheet passes through the gap between the first heating mechanism and the sizing roller assembly; conveying the solid electrolyte membrane through a solid electrolyte membrane unwinding mechanism located to the side of the electrode sheet unwinding mechanism so that the solid electrolyte membrane passes through the second heating mechanism and the gap between the sizing roller assembly and the electrode sheet; preheating the electrode sheet through the first heating mechanism; preheating the solid electrolyte membrane through the second heating mechanism; and roll-combining the preheated electrode sheet and solid electrolyte membrane through the sizing roller assembly to produce a composite electrode sheet. In some embodiments, the first heating mechanism and the second heating mechanism are respectively selected from a heater and / or a heating roller assembly. In some embodiments, the heating roller assembly includes one or more sets of heating rollers, each set of heating rollers including at least one heating roller. In some embodiments, the heating temperatures of the multiple heating rollers are the same or different, and / or the heating times of the multiple heating rollers are the same or different. In some embodiments, the heating time of the multiple heating rollers is 2 seconds or longer. In some embodiments, the heating temperatures of the first heating mechanism and the second heating mechanism are the same or different, and / or the heating times of the first heating mechanism and the second heating mechanism are the same or different. In some embodiments, the heating times of the first heating mechanism and the second heating mechanism are more than 2 seconds.In some embodiments, the heating mechanism is located between the electrode sheet unwinding mechanism and the shaping roller assembly, and is used to preheat the electrode sheet, the solid electrolyte membrane and the elastic member, wherein the elastic member is a protective film, and the protective film is transported through the gap between the shaping roller assembly and the solid electrolyte membrane.

[0015] In some embodiments, the preparation method of the present application includes: conveying the electrode sheet through an electrode sheet unwinding mechanism so that the electrode sheet passes through the gap between the guide roller, the heating mechanism, and the sizing roller assembly; conveying the solid electrolyte membrane through a solid electrolyte membrane unwinding mechanism located on the side of the electrode sheet unwinding mechanism so that the solid electrolyte membrane passes through the guide roller, the heating mechanism, the gap between the sizing roller assembly and the electrode sheet; controlling the electrode sheet and the solid electrolyte membrane to be bonded on the guide roller to prepare a bonded sheet; preheating the bonded sheet through the heating mechanism; and rolling the preheated bonded sheet through the sizing roller assembly to prepare a composite electrode sheet. In some embodiments, the preparation method of the present application includes: preheating the solid electrolyte membrane through the sizing roller assembly, wherein the sizing roller assembly is provided with a heating mechanism for preheating the solid electrolyte membrane; and heating and rolling the electrode sheet and the preheated solid electrolyte membrane through the sizing roller assembly to obtain a composite electrode sheet. In some embodiments, the preparation method of the present application includes: conveying the electrode sheet through an electrode sheet unwinding mechanism so that the electrode sheet passes through the gap between the sizing roller assembly; conveying the solid electrolyte membrane through a solid electrolyte membrane unwinding mechanism located on the side of the electrode sheet unwinding mechanism so that the solid electrolyte membrane reaches the sizing roller assembly for preheating and passes through the gap between the sizing roller assembly and the electrode sheet; and heating and roll-pressing the electrode sheet and the preheated solid electrolyte membrane together using the sizing roller assembly to form a composite electrode sheet; wherein the temperature of the solid electrolyte membrane is higher than that of the electrode sheet during the rolling. In some embodiments, the temperature of the solid electrolyte membrane is higher than that of the electrode sheet during the rolling. In some embodiments, the preparation method of the present application further includes: guiding the electrode sheet, or the solid electrolyte membrane, or both the electrode sheet and the solid electrolyte membrane, by a guide roller assembly to adjust the preheating time; the guide roller assembly is located between the electrode sheet unwinding mechanism and / or the solid electrolyte membrane unwinding mechanism and the sizing roller assembly. In some embodiments, the preparation method of the present application further includes: cooling the composite electrode sheet by a cooling roller; the cooling roller is located downstream of the sizing roller assembly. In some embodiments, the preparation method of the present application further includes: receiving the composite pole piece by a composite pole piece winding mechanism downstream of the sizing roller assembly. In some embodiments, the preparation method of the present application further includes: cooling the composite pole piece by a cooling roller between the sizing roller assembly and the composite pole piece winding mechanism.

[0016] In some embodiments, the preparation method of the present application further includes: separating the substrate covering the solid electrolyte membrane from the composite electrode sheet. In some embodiments, the preparation method of the present application further includes: receiving the substrate via a substrate reel between the sizing roller assembly and the composite electrode sheet reel; the substrate reel and the solid electrolyte membrane unwinding mechanism are located on the same side of the electrode sheet unwinding mechanism. In some embodiments, the sizing roller assembly includes a first sizing roller assembly and a second sizing roller assembly; the solid electrolyte membrane includes a first solid electrolyte membrane and a second solid electrolyte membrane, the first solid electrolyte membrane and the second solid electrolyte membrane being located on opposite sides of the electrode sheet, respectively; between the first sizing roller assembly and the second sizing roller assembly, receiving the first substrate located on the side of the first solid electrolyte membrane away from the electrode sheet via the first substrate reel; and downstream of the second sizing roller assembly, receiving the second substrate located on the side of the second solid electrolyte membrane away from the electrode sheet via the second substrate reel. In some embodiments, after the first substrate is separated from the composite membrane, the second solid electrolyte membrane is bonded to the composite membrane and passes through the gap between the second sizing roller assembly. In some embodiments, after the second substrate is separated from the composite electrode sheet, the composite electrode sheet is cooled. In some embodiments, the yield strength of the elastic member satisfies the following conditions: when the solid electrolyte membrane and the electrode sheet pass through the gap between the sizing roller assembly, the solid electrolyte membrane and the electrode sheet undergo plastic deformation, while the elastic member undergoes elastic deformation; the electrode sheet includes a positive electrode sheet and a negative electrode sheet. In some embodiments, the electrode sheet has a thick center and thin edges, and during rolling, the center region of the electrode sheet is subjected to greater force than the edge regions. In some embodiments, the electrode sheet is produced by a dry process. In some embodiments, the width of the elastic member is greater than or equal to the minimum width of the solid electrolyte membrane or the electrode sheet. In some embodiments, the elastic member is conveyed by a protective film unwinding mechanism; the protective film unwinding mechanism is located between the solid electrolyte membrane unwinding mechanism and the sizing roller assembly; and the elastic member is received by the protective film rewinding mechanism between the sizing roller assembly and the substrate rewinding mechanism. In some embodiments, within the gap, the protective film adheres to the surface of the solid electrolyte membrane. In some embodiments, the electrode sheet is preheated multiple times, with the preheating temperature increasing each time. In some embodiments, the shaping roller assembly includes a first shaping roller assembly and a second shaping roller assembly, and a heating mechanism is provided in both the first shaping roller assembly and the second shaping roller assembly.

[0017] In some embodiments, the solid electrolyte membrane includes a first solid electrolyte membrane and a second solid electrolyte membrane, the first solid electrolyte membrane and the second solid electrolyte membrane being located on either side of the electrode sheet, respectively; the first sizing roller assembly includes a first sizing steel roller and a first elastic roller, the first elastic roller being used for contact rolling the first solid electrolyte membrane; and / or the second sizing roller assembly includes a second sizing steel roller and a second elastic roller, the second elastic roller being used for contact rolling the second solid electrolyte membrane. In some embodiments, a ninth guide roller is disposed between the sizing roller assembly and the second heating mechanism, and the ninth guide roller is used to adjust the preheating time of the solid electrolyte membrane. In some embodiments, a third guide roller is disposed between the sizing roller assembly and the ninth guide roller, and the third guide roller is used to adjust the horizontal direction of the preheated electrode sheet and solid electrolyte membrane entering the sizing roller assembly.

[0018] Another aspect of the present application is to protect a composite electrode, which is prepared using the aforementioned preparation method.

[0019] Another aspect of the present application is to protect a lithium-ion battery, including a composite electrode prepared by the aforementioned preparation method.

[0020] Another aspect of the present application provides a composite electrode preparation device configured to perform the aforementioned preparation method, the preparation device comprising: a shaping roller assembly, the shaping roller assembly comprising a first shaping roller and a second shaping roller; an electrode sheet unwinding mechanism located upstream of the shaping roller assembly, for conveying the electrode sheet so that the electrode sheet passes through the gap between the first shaping roller and the second shaping roller; and a solid electrolyte membrane unwinding mechanism located to the side of the electrode sheet unwinding mechanism, for conveying the solid electrolyte membrane so that the solid electrolyte membrane passes through the gap between the first shaping roller and the second shaping roller; wherein an elastic member is provided between the shaping roller assembly and the solid electrolyte membrane. In some embodiments, the preparation device of the present application further comprises: a composite electrode sheet rewinding mechanism located downstream of the shaping roller assembly, for receiving the composite electrode sheet; and a substrate rewinding mechanism located between the shaping roller assembly and the composite electrode sheet rewinding mechanism, for receiving the substrate covered on the solid electrolyte membrane; the substrate rewinding mechanism and the solid electrolyte membrane unwinding mechanism are located on the same side of the electrode sheet unwinding mechanism. In some embodiments, the preparation device of the present application further includes: a protective film unwinding mechanism, located between the solid electrolyte membrane unwinding mechanism and the shaping roller assembly, for conveying the elastic member; and a protective film winding mechanism, located between the shaping roller assembly and the substrate winding mechanism, for receiving the elastic member; the elastic member is a protective film. In some embodiments, the elastic member is a rubber layer, which surrounds and covers the outside of the shaping roller assembly. In some embodiments, the preparation device of the present application further includes: a heating mechanism, located between the electrode sheet unwinding mechanism and the shaping roller assembly, for preheating the electrode sheet, or the solid electrolyte membrane, or the electrode sheet and the solid electrolyte membrane. In some embodiments, the preparation device of the present application further includes: a guide roller, located between the electrode sheet unwinding mechanism and the shaping roller assembly, for guiding the electrode sheet, or the solid electrolyte membrane, or the electrode sheet and the solid electrolyte membrane to adjust the preheating time.

[0021] On one hand, the present application provides a method for preparing a composite electrode sheet, which improves the consistency of the lateral thickness of the composite electrode sheet by adjusting the stress conditions of the electrode sheet and the solid electrolyte membrane during the rolling process.

[0022] A method for preparing a composite electrode sheet comprises: conveying an electrode sheet through an electrode sheet unwinding mechanism so that the electrode sheet passes through a gap between a sizing roller; conveying a solid electrolyte membrane through a solid electrolyte membrane unwinding mechanism located on the side of the electrode sheet unwinding mechanism so that the solid electrolyte membrane passes through a gap between the sizing roller and the electrode sheet; and rolling the solid electrolyte membrane located on the side of the electrode sheet onto the electrode sheet using a sizing roller to obtain a composite electrode sheet; wherein an elastic member is provided between the sizing roller and the solid electrolyte membrane rolled onto the electrode sheet; the yield limit of the elastic member satisfies the following conditions: when the solid electrolyte membrane and the electrode sheet pass through the gap between the sizing roller, the solid electrolyte membrane and the electrode sheet undergo plastic deformation, while the elastic member undergoes elastic deformation. The width of the elastic member is greater than or equal to the minimum width of the solid electrolyte membrane or the electrode sheet. The electrode sheet comprises a positive electrode sheet and / or a negative electrode sheet.

[0023] In some embodiments, the elastic member is a protective film that is transported through the gap between the sizing roller and the solid electrolyte membrane. In some embodiments, the elastic member is a rubber layer that surrounds and covers the outside of the sizing roller. In some embodiments, the solid electrolyte membranes located on both sides of the electrode pole piece are rolled onto the electrode pole piece by the sizing roller to obtain a composite pole piece. In some embodiments, the method further includes separating the substrate covering the solid electrolyte membrane from the composite pole piece. In some embodiments, the protective film is a polymer film or non-woven fabric. In some embodiments, the rubber layer is plastic, rubber, or silicone. In some embodiments, the preparation method further includes: receiving the composite pole piece downstream of the sizing roller by a composite pole piece winding mechanism; receiving the substrate by a substrate winding mechanism between the sizing roller and the composite pole piece winding mechanism; the substrate winding mechanism and the solid electrolyte membrane unwinding mechanism are located on the same side of the electrode pole piece unwinding mechanism. In some embodiments, the preparation method further includes: conveying the elastic member through a protective film unwinding mechanism; the protective film unwinding mechanism is located between the solid electrolyte membrane unwinding mechanism and the shaping roller; and receiving the elastic member through the protective film winding mechanism between the shaping roller and the substrate winding mechanism.

[0024] On the other hand, the present application provides a composite pole piece, which is obtained by the above-mentioned composite pole piece preparation method.

[0025] On the other hand, the present application provides a lithium-ion battery, which includes a composite pole piece prepared by the aforementioned composite pole piece preparation method.

[0026] Another aspect of the present application provides a composite electrode preparation device, comprising: shaping rollers, the shaping rollers comprising a first shaping roller and a second shaping roller; an electrode sheet unwinding mechanism, located upstream of the shaping rollers, for conveying the electrode sheet so that the electrode sheet passes through the gap between the first shaping roller and the second shaping roller; and a solid electrolyte membrane unwinding mechanism, located to the side of the electrode sheet unwinding mechanism, for conveying the solid electrolyte membrane so that the solid electrolyte membrane passes through the gap between the first shaping roller and the second shaping roller; an elastic member is provided between the shaping roller and the solid electrolyte membrane. In some embodiments, the device further comprises: a composite electrode sheet rewinding mechanism, located downstream of the shaping rollers, for receiving the composite electrode sheet; and a substrate rewinding mechanism, located between the shaping rollers and the composite electrode sheet rewinding mechanism, for receiving the substrate covered on the solid electrolyte membrane; the substrate rewinding mechanism and the solid electrolyte membrane unwinding mechanism are located on the same side of the electrode sheet unwinding mechanism. In some embodiments, the apparatus further comprises: a protective film unwinding mechanism, located between the solid electrolyte membrane unwinding mechanism and the shaping roller, for conveying the elastic member; and a protective film rewinding mechanism, located between the shaping roller and the substrate rewinding mechanism, for receiving the elastic member; the elastic member being a protective film. In some embodiments, the elastic member can also be a rubber layer, which surrounds and covers the outer side of the shaping roller.

[0027] The preparation method of the composite electrode sheet of the present application, during the rolling process of the shaping roller, the buffer provided by the elastic member enables the solid electrolyte membrane to better cover the electrode electrode sheet; at the same time, during the rolling process of the shaping roller, the electrode electrode sheet is thick in the middle, resulting in a greater force in the middle area than in the edge area, and the lateral thickness of the electrode electrode sheet tends to be consistent after rolling. It avoids the adverse effects of the phenomenon that the electrode electrode sheet is thick in the middle and thin at both ends on the rolling composite process, protects the electrode electrode sheet from being crushed, and can also achieve a better combination between the active material layer in the electrode electrode sheet and the solid electrolyte membrane. In addition, the composite electrode sheet prepared by the preparation method of the present application is applied to the battery, which helps to improve the overall safety performance of the battery; at the same time, the present application performs rolling during the composite process of the solid electrolyte membrane and the electrode electrode sheet, which realizes the bulging edge phenomenon in the rolling process that needs to be solved when the electrode electrode sheet is edge-cut, and avoids the influence of edge thinning on the interlayer composite.

[0028] On the other hand, the present application provides a device for preparing a composite electrode sheet, which adjusts the preheating time of the electrode sheet and / or solid electrolyte membrane through a guide roller, thereby improving the composite effect between the electrode sheet and the solid electrolyte membrane and improving the consistency of the composite electrode sheet.

[0029] In one aspect, the present application provides a device for preparing a composite electrode sheet, comprising: a sizing roller assembly, the sizing roller assembly comprising a first sizing roller and a second sizing roller; an electrode sheet unwinding mechanism, located upstream of the sizing roller assembly, for conveying the electrode sheet so that the electrode sheet passes through the gap between the first sizing roller and the second sizing roller; a solid electrolyte membrane unwinding mechanism, located to the side of the electrode sheet unwinding mechanism, for conveying the solid electrolyte membrane so that the solid electrolyte membrane passes through the gap between the electrode sheet and the sizing roller assembly; a heating roller, located between the electrode sheet unwinding mechanism and the sizing roller assembly, for preheating the electrode sheet and / or the solid electrolyte membrane; and a guide roller, located between the electrode sheet unwinding mechanism and the sizing roller assembly, for adjusting the preheating time of the electrode sheet or the solid electrolyte membrane. In some embodiments, the heating roller is used to preheat the electrode sheet. In some embodiments, the heating roller is used to preheat the solid electrolyte membrane. In some embodiments, the heating roller is used to preheat the electrode sheet and the solid electrolyte membrane. In some embodiments, the composite electrode sheet manufacturing apparatus further comprises: a composite electrode sheet rewinding mechanism, located downstream of the sizing roller assembly, for receiving the composite electrode sheet. In some embodiments, the composite electrode sheet manufacturing apparatus further comprises: a substrate rewinding mechanism, located between the sizing roller assembly and the composite electrode sheet rewinding mechanism, for receiving the substrate covering the solid electrolyte membrane; the substrate rewinding mechanism and the solid electrolyte membrane unwinding mechanism are located on the same side of the electrode sheet unwinding mechanism. In some embodiments, the composite electrode sheet manufacturing apparatus further comprises: an elastic member, located between the sizing roller assembly and the solid electrolyte membrane, for providing a buffer when the sizing roller assembly is rolling. In some embodiments, the composite electrode sheet manufacturing apparatus further comprises: a protective film unwinding mechanism, located between the electrode sheet unwinding mechanism and the sizing roller assembly, for conveying the protective film so that the protective film passes through the gap between the solid electrolyte membrane and the sizing roller assembly; and a protective film rewinding mechanism, located between the sizing roller assembly and the substrate rewinding mechanism, for receiving the protective film. In some embodiments, a guide roller is further located downstream of the sizing roller assembly to adjust the cooling time of the composite electrode sheet. In some embodiments, there are two solid electrolyte membrane unwinding mechanisms, which are symmetrically arranged on both sides of the electrode sheet unwinding mechanism.

[0030] On the other hand, the present application provides a composite electrode sheet, which is prepared by the device provided above. The composite electrode sheet preparation device of the present application is provided with a heating roller, which preheats the electrode sheet and / or the solid electrolyte membrane by the heating roller, thereby improving the softness of the electrode sheet and / or the solid electrolyte membrane, making it easier for the electrode sheet and the solid electrolyte membrane to be tightly bonded. The present application is provided with a plurality of guide rollers, so that during the preheating process, the preheating time of the electrode sheet and / or the solid electrolyte membrane can be adjusted as needed to achieve the expected preheating temperature, so that the electrode sheet and / or the solid electrolyte membrane can be fully preheated, the softness of the electrode sheet and / or the solid electrolyte membrane can be adjusted, the bonding strength between the electrode sheet and the solid electrolyte membrane can be enhanced, and the tight bonding degree of the composite electrode sheet can be improved. The preparation device of the composite electrode sheet of the present application utilizes the buffer provided by the elastic parts during rolling, so that the solid electrolyte membrane can better cover the electrode sheet; at the same time, during the rolling process of the shaping roller assembly, the electrode sheet is thick in the middle, resulting in the force in the middle area of ​​the electrode sheet being greater than the edge area, and the lateral thickness of the electrode sheet tends to be consistent after rolling.

[0031] On the other hand, the present application provides a method for preparing a composite electrode sheet, which includes: conveying the electrode sheet through an electrode sheet unwinding mechanism so that the electrode sheet passes through a first heater; conveying the first solid electrolyte membrane through a first solid electrolyte membrane unwinding mechanism located on one side of the electrode sheet unwinding mechanism so that the first solid electrolyte membrane passes through the first heater; heating the electrode sheet and the first solid electrolyte membrane through the first heater; compounding the heated electrode sheet and the first solid electrolyte membrane through a first shaping roller assembly to obtain a composite membrane sheet; conveying the second solid electrolyte membrane through a second solid electrolyte membrane unwinding mechanism located on the other side of the electrode sheet unwinding mechanism so that the second solid electrolyte membrane passes through a second heater; heating the composite membrane sheet and the second solid electrolyte membrane through the second heater; and compounding the heated composite membrane sheet and the second solid electrolyte membrane through a second shaping roller assembly to obtain a composite electrode sheet.

[0032] In some embodiments, at least one of the first sizing roller assembly and the second sizing roller assembly is configured as an elastic rolling assembly. In some embodiments, between the first sizing roller assembly and the second sizing roller assembly, a first substrate winding mechanism is used to receive a first substrate located on a side of the first solid electrolyte membrane away from the electrode sheet. In some embodiments, downstream of the second sizing roller assembly, a second substrate winding mechanism is used to receive a second substrate located on a side of the second solid electrolyte membrane away from the electrode sheet. In some embodiments, after the first substrate is separated from the composite membrane sheet, the second solid electrolyte membrane is attached to the composite membrane sheet and passes through the gap in the middle of the second sizing roller assembly. In some embodiments, after the second substrate is separated from the composite membrane sheet, the composite membrane sheet is cooled. In some embodiments, downstream of the second sizing roller assembly, the composite membrane sheet is received by the composite membrane sheet winding mechanism. In some embodiments, between the second sizing roller assembly and the composite membrane sheet winding mechanism, a cooling roller is used to cool the composite membrane sheet. In some embodiments, the first shaping roller assembly includes a first rigid roller and a first elastic roller disposed opposite the first rigid roller, the first elastic roller being located on the side of the first solid electrolyte membrane away from the electrode pad. The second shaping roller assembly includes a second rigid roller and a second elastic roller disposed opposite the second rigid roller, the second elastic roller being located on the side of the second solid electrolyte membrane away from the electrode pad. In some embodiments, the elastic rolling assembly includes a rigid roller and an elastic roller having a lower hardness than the rigid roller, the rigid roller and the elastic roller being symmetrically disposed on either side of the electrode pad. In some embodiments, the elastic roller includes a rigid roller and an elastic member, the elastic member being coated on the outside of the rigid roller.

[0033] On the other hand, the present application provides a composite pole piece, which is prepared using the aforementioned composite pole piece preparation method.

[0034] On the other hand, the present application provides a lithium-ion battery, which includes a composite pole piece prepared by the aforementioned composite pole piece preparation method.

[0035] In the preparation method of the above-mentioned composite electrode sheet, the heating process before rolling composite makes the composite effect between the solid electrolyte membrane and the electrode electrode sheet better; during the rolling process of the first shaping roller assembly and the second shaping roller assembly, the buffer provided by the elastic member in the elastic roller enables the solid electrolyte membrane to better cover the positive electrode sheet; on the other hand, during the rolling process, the electrode electrode sheet is thick in the middle, resulting in the force in the middle area being greater than the edge area. After rolling, the lateral thickness of the electrode electrode sheet tends to be consistent, avoiding the adverse effects of the phenomenon that the electrode electrode sheet is thick in the middle and thin at both ends on the rolling composite process; due to the combined effect of the heating process and the elastic member in the elastic roller, the electrode electrode sheet can be protected from being crushed, and the active material layer in the electrode electrode sheet and the solid electrolyte membrane can be better combined. In addition, the composite electrode sheet prepared by the preparation method of this application is applied to the battery, which helps to improve the overall safety performance of the battery.

[0036] On the other hand, the present application provides a method for preparing a composite electrode sheet, which overcomes the adverse effects of the rolling composite process caused by the phenomenon that the electrode sheet is thick in the middle and thin at both ends, and improves the consistency of the lateral thickness of the composite electrode sheet.

[0037] On the other hand, the present application provides a method for preparing a composite electrode sheet, which includes: conveying the electrode sheet through an electrode sheet unwinding mechanism so that the electrode sheet passes through a first heating roller assembly; conveying the first solid electrolyte membrane through a first solid electrolyte membrane unwinding mechanism located on one side of the electrode sheet unwinding mechanism so that the first solid electrolyte membrane passes through a first heating roller assembly; heating the electrode sheet and the first solid electrolyte membrane through the first heating roller assembly; compounding the heated electrode sheet and the first solid electrolyte membrane through a first shaping roller assembly to obtain a composite membrane sheet; conveying the second solid electrolyte membrane through a second solid electrolyte membrane unwinding mechanism located on the other side of the electrode sheet unwinding mechanism so that the second solid electrolyte membrane passes through a second heating roller assembly; heating the composite membrane sheet and the second solid electrolyte membrane through the second heating roller assembly; and compounding the heated composite membrane sheet and the second solid electrolyte membrane through a second shaping roller assembly to obtain a composite electrode sheet.

[0038] In some embodiments, at least one of the first and second sizing roller assemblies is configured as an elastic rolling assembly. In some embodiments, the elastic rolling assembly includes a rigid roller and an elastic roller with a lower hardness than the rigid roller, with the rigid roller and the elastic roller symmetrically positioned on either side of the electrode sheet. In some embodiments, the elastic roller includes a rigid roller and an elastic member, with the elastic member covering the outer surface of the rigid roller. In some embodiments, the elastic member is made of plastic, rubber, or silicone. In some embodiments, the first sizing roller assembly includes a first rigid roller and a first elastic roller positioned opposite the first rigid roller, with the first elastic roller positioned on the side of the first solid electrolyte membrane away from the electrode sheet. The second sizing roller assembly includes a second rigid roller and a second elastic roller positioned opposite the second rigid roller, with the second elastic roller positioned on the side of the second solid electrolyte membrane away from the electrode sheet. In some embodiments, the heating time of the first heating roller assembly is greater than 2 seconds. In some embodiments, the heating rollers in the first and second heating roller assemblies have the same or different heating temperatures and / or the same or different heating times. In some embodiments, both the first and second heating roller assemblies include at least one heating roller. In some embodiments, the first heating roller assembly includes a first heating roller and a second heating roller, arranged in sequence along the path of the electrode sheet; the first and second heating rollers are both used to heat the electrode sheet and the first solid electrolyte membrane, with the second heating roller having a higher temperature than the first heating roller. In some embodiments, the second heating roller assembly includes a third heating roller and a fourth heating roller, arranged in sequence along the path of the composite membrane sheet; the third and fourth heating rollers are both used to heat the composite membrane sheet and the second solid electrolyte membrane, with the fourth heating roller having a higher temperature than the third heating roller. In some embodiments, between the first and second sizing roller assemblies, a first substrate reeling mechanism receives a first substrate located on the side of the first solid electrolyte membrane away from the electrode sheet; downstream of the second sizing roller assembly, a second substrate reeling mechanism receives a second substrate located on the side of the second solid electrolyte membrane away from the electrode sheet. In some embodiments, after the first substrate is separated from the composite membrane sheet, the second solid electrolyte membrane is bonded to the composite membrane sheet and passes through the gap between the second sizing roller assembly.

[0039] On the other hand, the present application provides a composite pole piece, which is prepared using the aforementioned composite pole piece preparation method.

[0040] On the other hand, the present application provides a lithium-ion battery, which includes a composite pole piece prepared by the aforementioned composite pole piece preparation method.

[0041] In the preparation method of the above-mentioned composite electrode sheet, the heating process before rolling and laminating improves the composite effect between the solid electrolyte membrane and the electrode sheet, and the preheating effect of the electrode sheet and the solid electrolyte membrane is better. In addition, due to the use of a heated roller assembly, the residence time of the electrode sheet and the solid electrolyte membrane can be controlled, which can further improve the composite effect of the solid electrolyte membrane and the electrode sheet, and can be applied to the production of different composite electrode sheets. During the rolling process of the first and second shaping roller assemblies, the elastic members in the elastic rolling assembly provide a buffer, so that the solid electrolyte membrane can better cover the positive electrode sheet. At the same time, during the rolling process, the electrode sheet is thick in the middle, resulting in a greater force in the middle area than in the edge area. After rolling, the lateral thickness of the electrode sheet tends to be consistent, avoiding the adverse effects of the rolling composite process caused by the phenomenon that the electrode sheet is thick in the middle and thin at both ends. Due to the combined effect of the heating process and the elastic members in the elastic roller, the electrode sheet can be protected from being crushed, and the active material layer in the electrode sheet and the solid electrolyte membrane can be better bonded. In addition, the composite electrode prepared by the preparation method of the present application is applied to the battery, which helps to improve the overall safety performance of the battery. At the same time, the present application uses a two-step process to successively composite the solid electrolyte membranes on both sides of the electrode onto the electrode. This process can better match the situation when the active material layer composition on both sides of the current collector is different or the composition and structure of the solid electrolyte membrane are different, and has better matching and adaptability to different formula systems.

[0042] On the other hand, the present application provides a preparation device for a composite electrode sheet, which includes: a shaping roller assembly, including a first shaping roller and a second shaping roller, for rolling and compounding the electrode electrode sheet, the solid electrolyte membrane and the protective membrane to form a composite electrode sheet; an electrode electrode sheet unwinding mechanism, located upstream of the shaping roller assembly, for conveying the electrode electrode sheet so that the electrode electrode sheet passes through the gap between the first shaping roller and the second shaping roller; a solid electrolyte membrane unwinding mechanism, located on the side of the electrode electrode sheet unwinding mechanism, for conveying the solid electrolyte membrane so that the solid electrolyte membrane passes through the gap between the electrode electrode sheet and the shaping roller assembly; a protective film unwinding mechanism, located between the solid electrolyte membrane unwinding mechanism and the shaping roller assembly, for conveying the protective film so that the protective film passes through the gap between the solid electrolyte membrane and the shaping roller assembly; a heating mechanism, located between the electrode electrode sheet unwinding mechanism and the shaping roller assembly, for preheating the electrode electrode sheet, the solid electrolyte membrane and the protective membrane; and a cooling roller, located downstream of the shaping roller assembly, for cooling the composite electrode sheet. In some embodiments, the composite electrode sheet preparation apparatus further includes a composite electrode sheet rewinding mechanism, located downstream of the shaping roller assembly, for receiving the composite electrode sheet. In some embodiments, the composite electrode sheet preparation apparatus further includes a substrate rewinding mechanism, located between the shaping roller assembly and the composite electrode sheet rewinding mechanism, for receiving the substrate covering the solid electrolyte membrane; the substrate rewinding mechanism and the solid electrolyte membrane unwinding mechanism are located on the same side of the electrode sheet unwinding mechanism.

[0043] In some embodiments, the preparation device of the composite electrode further includes a protective film winding mechanism, which is located between the shaping roller assembly and the substrate winding mechanism and is used to receive the protective film. In some embodiments, the protective film is a polymer film or a non-woven fabric. In some embodiments, the heating mechanism preheats the electrode electrode, the solid electrolyte membrane and the protective film for a time ≥ 2S. In some embodiments, there are multiple heating mechanisms for preheating the electrode electrode, the solid electrolyte membrane and the protective film multiple times at the same time, and the preheating temperature increases successively. In some embodiments, there are two solid electrolyte membrane unwinding mechanisms, which are symmetrically arranged on both sides of the electrode electrode unwinding mechanism.

[0044] On the other hand, the present application provides a composite pole piece, which is prepared by the above-mentioned composite pole piece preparation device.

[0045] On the other hand, the present application provides a lithium-ion battery, which includes the above-mentioned composite electrode.

[0046] The composite electrode preparation device of the present application is provided with a heating mechanism, which preheats the electrode electrode, solid electrolyte membrane and protective membrane at the same time through the heating mechanism, thereby improving the overall softness of the electrode electrode, solid electrolyte membrane and protective membrane, and improving the ductility of the three at the same time, and improving the plasticity. Therefore, when the shaping roller assembly rolls and composites the electrode electrode, solid electrolyte membrane and protective membrane as a whole, the adjacent membranes are more tightly engaged, thereby improving the bonding strength between the membranes and improving the degree of composite between the electrode electrode, solid electrolyte membrane and protective membrane. In the composite electrode preparation device of the present application, before the roll-pressing lamination process, the protective film has been attached to both sides of the electrode electrode and the solid electrolyte membrane, playing a protective role. During the roll-pressing lamination process, the protective film provides a buffer to adjust the stress of the electrode electrode and the solid electrolyte membrane during the roll-pressing process, so that the solid electrolyte membrane can better cover the electrode electrode; and the stress of the electrode electrode and the solid electrolyte membrane during the roll-pressing process is uniform. After the roll-pressing, the transverse thickness of the electrode electrode tends to be consistent, avoiding the adverse effects of the electrode electrode being thick in the middle and thin at the ends on the roll-pressing lamination process, preventing the electrode electrode from being crushed, improving the degree of lamination between the electrode electrode, the solid electrolyte membrane and the protective film, and improving the consistency of the transverse thickness of the composite electrode. The composite electrode preparation device of the present application is provided with a cooling roller, which can quickly reduce the temperature of the composite electrode emerging from the gap of the shaping roller assembly, so that the composite electrode can be continuously rolled up, improving production efficiency; at the same time, the cooling roller also provides shaping treatment for the composite electrode.

[0047] On one hand, the present application provides a method for preparing a composite electrode sheet, which overcomes the adverse effects of the phenomenon of the electrode sheet being "thick in the middle and thin at both ends" on the rolling composite process, thereby preventing the electrode sheet from being crushed; and during the rolling process, the electrode sheet and the solid electrolyte membrane are subjected to uniform force, thereby improving the consistency of the lateral thickness of the composite electrode sheet. A method for preparing a composite electrode sheet comprises the following steps: conveying the electrode sheet through an electrode sheet unwinding mechanism so that the electrode sheet passes through the gap between the heating mechanism and the shaping roller assembly; conveying the solid electrolyte membrane through a solid electrolyte membrane unwinding mechanism located on the side of the electrode sheet unwinding mechanism so that the solid electrolyte membrane passes through the gap between the shaping roller assembly and the electrode sheet; preheating the electrode sheet through the heating mechanism to produce a preheating sheet; and rolling the preheating sheet and the solid electrolyte membrane through the shaping roller assembly to produce a composite electrode sheet.

[0048] In some embodiments, the solid electrolyte membranes located on both sides of the electrode plate are rolled and composited onto the electrode plate by a sizing roller assembly to obtain a composite plate. In some embodiments, the electrode plate is preheated several times, and the temperature of the preheating is gradually increased. In some embodiments, the preheating time is ≥2S. In some embodiments, an elastic member is provided between the sizing roller assembly and the solid electrolyte membrane. In some embodiments, the elastic member is a protective film, and the protective film is transported through the gap between the sizing roller assembly and the solid electrolyte membrane. In some embodiments, the elastic member is an adhesive layer, and the adhesive layer surrounds and covers the outside of the sizing roller assembly. In some embodiments, the solid electrolyte membrane is covered with a substrate, and the method for preparing the composite plate further includes the following steps: separating the substrate covering the solid electrolyte membrane from the composite plate. In some embodiments, the method for preparing the composite plate further includes cooling the composite plate. In some embodiments, the method for preparing a composite electrode sheet further includes: receiving the composite electrode sheet via a composite electrode sheet rewinding mechanism downstream of the sizing roller assembly; receiving the substrate via a substrate rewinding mechanism between the sizing roller assembly and the composite electrode sheet rewinding mechanism; the substrate rewinding mechanism and the solid electrolyte membrane unwinding mechanism being located on the same side of the electrode sheet unwinding mechanism. In some embodiments, the method for preparing a composite electrode sheet further includes: delivering an elastic member via a protective film unwinding mechanism; the protective film unwinding mechanism being located between the solid electrolyte membrane unwinding mechanism and the sizing roller assembly; and receiving the elastic member via the protective film rewinding mechanism between the sizing roller assembly and the substrate rewinding mechanism.

[0049] On the other hand, the present application provides a composite pole piece, which is prepared according to the above-mentioned preparation method.

[0050] On the other hand, the present application provides a lithium-ion battery, which includes the above-mentioned composite electrode.

[0051] The preparation method of the composite electrode sheet of the present application performs a preheating treatment on the electrode electrode sheet before the rolling and compounding step. The preheating temperature increases the flexibility of the electrode electrode sheet, thereby improving the ductility of the electrode electrode sheet and improving the plasticity of the electrode electrode sheet. Therefore, when the shaping roller assembly rolls the electrode electrode sheet and the solid electrolyte membrane, the electrode electrode sheet and the solid electrolyte membrane are more tightly engaged, thereby improving the bonding strength between the two layers of the membrane and making it easier to achieve a tight compounding effect. In the preparation method of the composite electrode sheet of the present application, compared with preheating the electrode electrode sheet and the solid electrolyte membrane as a whole, the rolling device for preheating the electrode electrode sheet separately has a simpler structure and makes the electrode electrode sheet preheated more fully. There is no need to consider factors such as the slow preheating speed of the composite membrane and the different preheating temperatures of the solid electrolyte membrane. The preparation method of the composite electrode sheet of the present application, during the rolling process of the shaping roller assembly, the elastic member provides a buffer to adjust the stress conditions of the electrode electrode sheet and the solid electrolyte membrane during the rolling process, so that the solid electrolyte membrane can better cover the electrode electrode sheet; and the stress of the electrode electrode sheet and the solid electrolyte membrane during the rolling process is made uniform, so that the lateral thickness of the electrode electrode sheet after rolling tends to be consistent, avoiding the adverse effects of the rolling composite process caused by the phenomenon that the electrode electrode sheet is thick in the middle and thin at both ends, and avoiding the crushing of the electrode electrode sheet; under the joint action of the heating process and the elastic member, the degree of composite between the electrode electrode sheet and the solid electrolyte membrane is improved, and the consistency of the lateral thickness of the composite electrode sheet is improved. In addition, the composite electrode sheet prepared by the preparation method of the present application is applied to the battery, which helps to improve the overall safety performance of the battery.

[0052] On one hand, the present application provides a method for preparing a composite electrode sheet, comprising the following steps: conveying the electrode sheet through an electrode sheet unwinding mechanism so that the electrode sheet passes through a first heating mechanism and a gap between a sizing roller assembly; conveying a solid electrolyte membrane through a solid electrolyte membrane unwinding mechanism located to the side of the electrode sheet unwinding mechanism so that the solid electrolyte membrane passes through a second heating mechanism and the gap between the sizing roller assembly and the electrode sheet; preheating the electrode sheet through the first heating mechanism; preheating the solid electrolyte membrane through the second heating mechanism; and rolling the preheated electrode sheet and solid electrolyte membrane together through the sizing roller assembly to prepare a composite electrode sheet. This preparation method independently preheats the electrode sheet and solid electrolyte membrane before rolling and laminating, thereby enhancing the bonding strength between the electrode sheet and the solid electrolyte membrane and improving the tightness of the composite electrode sheet.

[0053] In some embodiments, an elastic member is disposed between the sizing roller assembly and the solid electrolyte membrane. In some embodiments, the elastic member is a protective film, which is transported through the gap between the sizing roller assembly and the solid electrolyte membrane and adheres to the surface of the composite electrode sheet. In some embodiments, the method for preparing a composite electrode sheet further comprises the step of separating the protective film from the composite electrode sheet. In some embodiments, the elastic member is an adhesive layer, which wraps around and covers the outer side of the sizing roller assembly. In some embodiments, a ninth guide roller is disposed between the sizing roller assembly and the second heating mechanism to adjust the preheating time of the solid electrolyte membrane. In some embodiments, a third guide roller is disposed between the sizing roller assembly and the ninth guide roller to adjust the horizontal direction of the preheated electrode sheet and solid electrolyte membrane entering the sizing roller assembly. In some embodiments, the solid electrolyte membranes located on both sides of the electrode sheet are rolled and laminated onto the electrode sheet by the sizing roller assembly to produce the composite electrode sheet. In some embodiments, the preheating time is ≥ 2 seconds. In some embodiments, the solid electrolyte membrane is covered with a substrate, and the preparation method further includes the following steps: separating the substrate covering the solid electrolyte membrane from the composite electrode sheet. In some embodiments, the preparation method of the composite electrode sheet further includes cooling the composite electrode sheet. In some embodiments, the preparation method of the composite electrode sheet further includes: receiving the composite electrode sheet through a composite electrode sheet winding mechanism downstream of the shaping roller assembly; receiving the substrate through a substrate winding mechanism between the shaping roller assembly and the composite electrode sheet winding mechanism; the substrate winding mechanism and the solid electrolyte membrane unwinding mechanism are located on the same side of the electrode sheet unwinding mechanism. In some embodiments, the preparation method of the composite electrode sheet further includes: conveying the elastic member through a protective film unwinding mechanism; the protective film unwinding mechanism is located between the solid electrolyte membrane unwinding mechanism and the shaping roller assembly; and receiving the elastic member through the protective film winding mechanism between the shaping roller assembly and the substrate winding mechanism. On the other hand, the present application provides a composite electrode sheet, which is prepared according to the above-mentioned preparation method.

[0054] On the other hand, the present application provides a lithium-ion battery, which includes the above-mentioned composite electrode.

[0055] The preparation method of the composite electrode of the present application takes into account that the electrode electrode and the solid electrolyte membrane are made of different materials and have different suitable heating temperatures. Therefore, before the rolling composite step, the electrode electrode and the solid electrolyte membrane are separately preheated by the first heating mechanism and the second heating mechanism respectively to ensure that the electrode electrode and the solid electrolyte membrane are fully preheated, and there is no mutual influence during the preheating process, thereby ensuring the preheating effect; the electrode electrode and the solid electrolyte membrane will soften after preheating compared to before preheating, thereby improving the softness of the electrode electrode and the solid electrolyte membrane, and improving the ductility of the electrode electrode and the solid electrolyte membrane, so that the electrode electrode can be quickly composited with the solid electrolyte membrane in the rolling composite step, and the electrode electrode and the solid electrolyte membrane are more tightly bitten, thereby improving the bonding strength between the two membranes, and making it easier to achieve a tight composite effect.

[0056] The preparation method of the composite electrode sheet of the present application, during the rolling process of the shaping roller assembly, adjusts the stress conditions of the electrode electrode sheet and the solid electrolyte membrane during the rolling process through the buffer provided by the elastic member, so that the solid electrolyte membrane can better cover the electrode electrode sheet; and makes the stress of the electrode electrode sheet and the solid electrolyte membrane uniform during the rolling process, so that the lateral thickness of the electrode electrode sheet after rolling tends to be consistent, avoiding the adverse effects of the rolling composite process caused by the phenomenon that the electrode electrode sheet is thick in the middle and thin at both ends, and avoiding the crushing of the electrode electrode sheet; improving the degree of composite between the electrode electrode sheet and the solid electrolyte membrane, and improving the consistency of the lateral thickness of the composite electrode sheet. In addition, the composite electrode sheet prepared by the preparation method of the present application is applied to the battery, which helps to improve the overall safety performance of the battery.

[0057] On the one hand, the present application provides a method for preparing a composite electrode sheet, which preheats the electrode sheet and the solid electrolyte membrane, adjusts the softness of the electrode sheet and the solid electrolyte membrane, enhances the bonding strength between the electrode sheet and the solid electrolyte membrane, and improves the tightness of the composite electrode sheet.

[0058] A method for preparing a composite electrode sheet comprises the following steps: conveying the electrode sheet through an electrode sheet unwinding mechanism so that the electrode sheet passes through a gap between a guide roller, a heating mechanism, and a shaping roller assembly; conveying a solid electrolyte membrane through a solid electrolyte membrane unwinding mechanism located on the side of the electrode sheet unwinding mechanism so that the solid electrolyte membrane passes through a gap between the guide roller, the heating mechanism, the shaping roller assembly, and the electrode sheet; controlling the electrode sheet and the solid electrolyte membrane to be bonded on the guide roller to prepare a bonded sheet; preheating the bonded sheet through the heating mechanism; and rolling the preheated bonded sheet through the shaping roller assembly to prepare a composite electrode sheet.

[0059] In some embodiments, the method for preparing a composite electrode sheet further comprises: receiving the composite electrode sheet via a composite electrode sheet rewinding mechanism downstream of the sizing roller assembly; receiving the substrate via a substrate rewinding mechanism between the sizing roller assembly and the composite electrode sheet rewinding mechanism; the substrate rewinding mechanism and the solid electrolyte membrane unwinding mechanism being located on the same side of the electrode sheet unwinding mechanism. In some embodiments, an elastic member is disposed between the sizing roller assembly and the solid electrolyte membrane. In some embodiments, the method for preparing a composite electrode sheet further comprises: conveying the elastic member via a protective film unwinding mechanism; the protective film unwinding mechanism being located between the solid electrolyte membrane unwinding mechanism and the sizing roller assembly; and receiving the elastic member via the protective film unwinding mechanism between the sizing roller assembly and the substrate rewinding mechanism. In some embodiments, the elastic member is a protective film, which is transported through the gap between the sizing roller assembly and the solid electrolyte membrane, where it adheres to the surface of the solid electrolyte membrane. In some embodiments, the method for preparing a composite electrode sheet further comprises: separating the protective film from the surface of the solid electrolyte membrane after the composite electrode sheet is prepared. In some embodiments, the elastic member is an adhesive layer, and the adhesive layer surrounds and covers the outside of the shaping roller assembly. In some embodiments, the solid electrolyte membranes located on both sides of the electrode plate are rolled and composited on the electrode plate by the shaping roller assembly to obtain a composite plate. In some embodiments, the bonding sheet is preheated several times, and the temperature of the preheating is increased successively. In some embodiments, the preheating time is ≥2S. In some embodiments, the method for preparing the composite plate further includes the following steps: separating the substrate covering the solid electrolyte membrane from the composite plate. In some embodiments, the method for preparing the composite plate further includes cooling the composite plate. On the other hand, the present application provides a composite plate, which is prepared according to the preparation method provided above.

[0060] On the other hand, the present application provides a lithium-ion battery, which includes the above-mentioned composite electrode.

[0061] The present invention's composite electrode preparation method involves laminating the electrode and solid electrolyte membrane prior to the roll-combination step, followed by preheating. This lamination step is equivalent to completing a pre-roll-combination process, reducing electrode rebound. The laminated sheet is then preheated, ensuring uniform heating throughout the entire sheet and consistent preheating temperature. As the sheet temperature rises, the flexibility of the electrode and solid electrolyte membrane increases, and the bonding strength between the electrode and solid electrolyte membrane increases, making it easier to achieve a tight composite during the roll-combination process.

[0062] The preparation method of the composite electrode sheet of the present application, during the rolling process of the shaping roller assembly, adjusts the stress conditions of the electrode electrode sheet and the solid electrolyte membrane during the rolling process through the buffer provided by the elastic member, so that the solid electrolyte membrane can better cover the electrode electrode sheet; and makes the stress of the electrode electrode sheet and the solid electrolyte membrane uniform during the rolling process, so that the lateral thickness of the electrode electrode sheet after rolling tends to be consistent, avoiding the adverse effects of the rolling composite process caused by the phenomenon that the electrode electrode sheet is thick in the middle and thin at both ends, and avoiding the crushing of the electrode electrode sheet; improving the degree of composite between the electrode electrode sheet and the solid electrolyte membrane, and improving the consistency of the lateral thickness of the composite electrode sheet. In addition, the composite electrode sheet prepared by the preparation method of the present application is applied to the battery, which helps to improve the overall safety performance of the battery.

[0063] On the other hand, the present application provides a method for preparing a composite electrode sheet, which overcomes the problem of poor solid electrolyte membrane composite effect caused by thinning of the electrode electrode edge, and improves the consistency of the lateral thickness of the composite electrode sheet formed by the electrode electrode sheet and the solid electrolyte membrane.

[0064] A method for preparing a composite electrode sheet, comprising: preheating a solid electrolyte membrane through a shaping roller assembly, wherein a heating mechanism is provided in the shaping roller assembly for preheating the solid electrolyte membrane; and

[0065] Heating and rolling the electrode sheet and the preheated solid electrolyte membrane using a shaping roller assembly to obtain a composite electrode sheet;

[0066] Among them, the electrode plates include positive electrode plates and negative electrode plates.

[0067] In some embodiments, the sizing roller assembly includes a first sizing roller and a second sizing roller; at least one of the first and second sizing rollers is equipped with a heating mechanism. The first and second sizing rollers are used to roll the solid electrolyte membranes located on either side of the electrode sheet onto the electrode sheet, thereby forming a composite electrode sheet. In some embodiments, both the first and second sizing rollers are equipped with heating mechanisms. In some embodiments, an elastic member is positioned between the sizing roller assembly and the solid electrolyte membrane rolled onto the electrode sheet. Optionally, the elastic member is a protective film that is transported through the gap between the sizing roller assembly and the solid electrolyte membrane. In some embodiments, the protective film is a polymer film or non-woven fabric. In some embodiments, the elastic member is an adhesive layer that surrounds and covers the outside of the sizing roller assembly. In some embodiments, the adhesive layer is made of plastic, rubber, or silicone. In some embodiments, the preparation method of the present application further comprises separating the substrate covering the solid electrolyte membrane from the composite electrode sheet.

[0068] The preparation method of the composite electrode provided in the present application is combined with the structure and includes the following steps: the electrode electrode is conveyed by the electrode electrode unwinding mechanism so that the electrode electrode passes through the gap in the middle of the shaping roller assembly; the solid electrolyte membrane is conveyed by the solid electrolyte membrane unwinding mechanism located on the side of the electrode electrode unwinding mechanism so that the solid electrolyte membrane reaches the shaping roller assembly for preheating and passes through the gap between the shaping roller assembly and the electrode electrode; and the electrode electrode and the preheated solid electrolyte membrane are heated and rolled by the shaping roller assembly to obtain a composite electrode; wherein, the temperature of the solid electrolyte membrane is higher than that of the electrode electrode during rolling; the electrode electrode includes a positive electrode and a negative electrode.

[0069] In some embodiments, the preparation method further comprises: receiving the composite electrode sheet via a composite electrode sheet rewinding mechanism downstream of the sizing roller assembly; receiving the substrate via a substrate rewinding mechanism between the sizing roller assembly and the composite electrode sheet rewinding mechanism; the substrate rewinding mechanism and the solid electrolyte membrane unwinding mechanism being located on the same side of the electrode sheet unwinding mechanism. In some embodiments, the elastic member is a protective film, and the preparation method further comprises: conveying the protective film via the protective film unwinding mechanism so that the protective film passes through the gap between the solid electrolyte membrane and the sizing roller assembly; and receiving the elastic member via the protective film rewinding mechanism between the sizing roller assembly and the substrate rewinding mechanism.

[0070] On the other hand, the present application provides a composite pole piece, which is obtained by the above-mentioned composite pole piece preparation method.

[0071] On the other hand, the present application provides a solid-state battery, which includes a composite electrode sheet prepared by the aforementioned composite electrode sheet preparation method.

[0072] The above-mentioned preparation method of the composite electrode sheet, by using elastic parts to provide buffer for the rolling process during the compounding process, avoids the problem of low compounding efficiency due to the poor deformation resistance of the rigid roller on the one hand, and avoids the adverse effects of the rolling compounding process caused by the phenomenon that the electrode sheet is thick in the middle and thin at both ends on the rolling compounding process on the other hand. When preparing the composite electrode sheet by the preparation method of the present application, the solid electrolyte membrane and the electrode sheet are heated, so that the ductility of the solid electrolyte membrane and the electrode sheet is improved; and the heating time of the solid electrolyte membrane by the shaping roller assembly is longer than the heating time of the electrode sheet by the shaping roller assembly, which further makes the ductility of the solid electrolyte membrane better than that of the electrode sheet; in addition, during rolling, due to the phenomenon that the thickness of the middle area of ​​the electrode sheet itself is greater than that of the edge area, the force in the middle area of ​​the electrode sheet is greater than that of the edge area; due to the combination of various reasons, the solid electrolyte membrane after rolling can better cover the surface of the electrode sheet, and the active material layer in the electrode sheet and the solid electrolyte membrane are better combined, and the consistency of the lateral thickness of the composite electrode sheet can also be effectively improved. In addition, the composite electrode prepared by the preparation method of the present application is applied to the battery, which helps to improve the overall safety performance of the battery.

[0073] On the one hand, the present application provides a method for preparing a composite electrode sheet, which includes: unwinding and conveying an electrode sheet; unwinding a first solid electrolyte membrane located on one side of the electrode sheet, and compounding the electrode sheet and the first solid electrolyte membrane through a first shaping roller assembly to obtain a composite membrane sheet; unwinding a second solid electrolyte membrane located on the other side of the electrode sheet, and compounding the composite membrane sheet and the second solid electrolyte membrane through a second shaping roller assembly to obtain a composite electrode sheet; wherein at least one of the first shaping roller assembly and the second shaping roller assembly is configured as an elastic rolling assembly.

[0074] In some embodiments, the elastic rolling assembly includes an elastic roller, the elastic roller comprising the elastic roller being used to contact-roll the first solid electrolyte membrane, and / or the elastic roller being used to contact-roll the first solid electrolyte membrane. In some embodiments, the elastic rolling assembly includes a shaped steel roller and an elastic roller having a lower hardness than the shaped steel roller. In some embodiments, the elastic roller includes a rigid roller and an elastic member, the elastic member being coated on the outside of the rigid roller. In some embodiments, the elastic member is made of plastic, rubber, or silicone. In some embodiments, the elastic roller includes a rigid roller and a protective film, the rigid roller acting on the protective film during rolling to provide a cushioning effect. In some embodiments, the first shaped steel roller assembly includes a first shaped steel roller and a first elastic roller, the first elastic roller being used to contact-roll the first solid electrolyte membrane. In some embodiments, the second shaped steel roller assembly includes a second shaped steel roller and a second elastic roller, the second elastic roller being used to contact-roll the second solid electrolyte membrane. In some embodiments, the step of combining the electrode sheet and the first solid electrolyte membrane through a first sizing roller assembly further includes heating the first sizing roller assembly. In some embodiments, the step of combining the composite membrane sheet and the second solid electrolyte membrane through a second sizing roller assembly further includes removing the second sizing roller assembly. In some embodiments, between the first and second sizing roller assemblies, a first substrate reeling mechanism receives a first substrate located on the side of the first solid electrolyte membrane away from the electrode sheet. In some embodiments, downstream of the second sizing roller assembly, a second substrate reeling mechanism receives a second substrate located on the side of the second solid electrolyte membrane away from the electrode sheet. In some embodiments, after the first substrate is separated from the composite membrane sheet, the second solid electrolyte membrane is bonded to the composite membrane sheet and passed through the gap between the second sizing roller assembly. In some embodiments, after the second substrate is separated from the composite electrode sheet, the composite electrode sheet is cooled. In some embodiments, downstream of the second sizing roller assembly, the composite electrode sheet is received by a composite electrode sheet reeling mechanism. In some embodiments, between the second sizing roller assembly and the composite electrode sheet reeling mechanism, a cooling roller is used to cool the composite electrode sheet.

[0075] On the other hand, the present application provides a composite pole piece, which is prepared using the aforementioned composite pole piece preparation method.

[0076] On the other hand, the present application provides a lithium-ion battery, which includes a composite pole piece prepared by the above-mentioned composite pole piece preparation method.

[0077] In the preparation method of the above-mentioned composite electrode sheet, during the rolling process of the first shaping roller assembly and the second shaping roller assembly, the buffer provided by the elastic member in the elastic roller enables the solid electrolyte membrane to better cover the positive electrode sheet, thereby achieving an excellent composite effect; at the same time, during the rolling process, the electrode sheet is thick in the middle, resulting in a greater force in the middle area than in the edge area. After rolling, the lateral thickness of the electrode sheet tends to be consistent, avoiding the adverse effects of the rolling composite process caused by the phenomenon that the electrode sheet is thick in the middle and thin at both ends; on the other hand, the rigidity of the shaping roller can provide better inter-membrane bonding and shaping effect for the composite membrane sheet or composite electrode sheet. The combination of a rigid roller and an elastic roller can protect the electrode sheet from being crushed, while also enabling a better combination between the active material layer in the electrode sheet and the solid electrolyte membrane. In addition, the composite electrode sheet prepared by the preparation method of the present application is applied to the battery, which helps to improve the overall safety performance of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the conventional technology, the following briefly introduces the drawings required for use in the embodiments or the conventional technology descriptions. Obviously, the drawings described below are merely embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the disclosed drawings without any creative work.

[0079] FIG1 is a flow chart of a method for preparing a composite electrode provided in one embodiment of the present application.

[0080] FIG2 is a schematic structural diagram of a composite electrode before rolling provided in an embodiment of the present application.

[0081] FIG3 is a schematic structural diagram of a rolled composite electrode provided in an embodiment of the present application.

[0082] FIG4 is a schematic structural diagram of a composite electrode preparation device provided in one embodiment of the present application.

[0083] FIG5 is a schematic structural diagram of a composite electrode preparation device provided in one embodiment of the present application.

[0084] FIG6 is a schematic structural diagram of a composite electrode preparation device provided in a comparative example of the present application.

[0085] FIG7 is a schematic structural diagram of a composite electrode preparation device provided in one embodiment of the present application.

[0086] FIG8 is a schematic structural diagram of a composite electrode preparation device provided in one embodiment of the present application.

[0087] FIG9 is a schematic structural diagram of a composite electrode preparation device provided in one embodiment of the present application.

[0088] FIG10 is a schematic structural diagram of a composite electrode preparation device provided in one embodiment of the present application.

[0089] FIG11 is a schematic structural diagram of a composite electrode preparation device provided in one embodiment of the present application.

[0090] FIG12 is a schematic structural diagram of a composite electrode preparation device provided in one embodiment of the present application.

[0091] FIG13 is a schematic structural diagram of a composite electrode preparation device provided in one embodiment of the present application.

[0092] FIG14 is a flow chart of a method for preparing a composite electrode provided in one embodiment of the present application.

[0093] FIG15 is a schematic structural diagram of a composite electrode preparation device provided in one embodiment of the present application.

[0094] FIG16 is a schematic structural diagram of a composite electrode preparation device provided in one embodiment of the present application.

[0095] FIG17 is a flow chart of a method for preparing a composite electrode provided in one embodiment of the present application.

[0096] FIG18 is a schematic structural diagram of a composite electrode preparation device provided in one embodiment of the present application.

[0097] FIG19 is a schematic structural diagram of a composite electrode preparation device provided in one embodiment of the present application.

[0098] FIG20 is a schematic structural diagram of a device for preparing a composite electrode according to an embodiment of the present application.

[0099] FIG21 is a schematic structural diagram of a device for preparing a composite electrode according to an embodiment of the present application.

[0100] FIG22 is a schematic structural diagram of a device for preparing a composite electrode according to an embodiment of the present application.

[0101] FIG23 is a flow chart of a method for preparing a composite electrode in one embodiment of the present application.

[0102] FIG24 is a schematic structural diagram of a device for preparing a composite electrode according to an embodiment of the present application.

[0103] FIG25 is a schematic structural diagram of a device for preparing a composite electrode according to an embodiment of the present application.

[0104] FIG26 is a schematic structural diagram of a device for preparing a composite electrode according to an embodiment of the present application.

[0105] FIG27 is a schematic structural diagram of a device for preparing a composite electrode according to an embodiment of the present application.

[0106] FIG28 is a schematic structural diagram of a device for preparing a pair of proportional composite electrodes according to the present application.

[0107] FIG29 is a schematic structural diagram of a device for preparing a pair of proportional composite electrodes of the present application.

[0108] FIG30 is a schematic structural diagram of a device for preparing a pair of proportional composite electrodes of the present application.

[0109] FIG31 is a flow chart of a method for preparing a composite electrode in one embodiment of the present application.

[0110] FIG32 is a schematic structural diagram of a device for preparing a composite electrode according to an embodiment of the present application.

[0111] FIG33 is a schematic structural diagram of a device for preparing a composite electrode according to an embodiment of the present application.

[0112] FIG34 is a schematic structural diagram of a device for preparing a composite electrode according to an embodiment of the present application.

[0113] FIG35 is a schematic structural diagram of a device for preparing a composite electrode according to an embodiment of the present application.

[0114] FIG36 is a schematic structural diagram of a device for preparing a pair of proportional composite electrodes according to the present application.

[0115] FIG37 is a flow chart of a method for preparing a composite electrode in one embodiment of the present application.

[0116] FIG38 is a schematic structural diagram of a device for preparing a composite electrode according to an embodiment of the present application.

[0117] FIG39 is a schematic structural diagram of a device for preparing a composite electrode according to an embodiment of the present application.

[0118] FIG40 is a schematic structural diagram of a device for preparing a composite electrode according to an embodiment of the present application.

[0119] FIG41 is a schematic structural diagram of a device for preparing a composite electrode according to an embodiment of the present application.

[0120] FIG42 is a flow chart of a method for preparing a composite electrode provided in one embodiment of the present application.

[0121] FIG43 is a schematic structural diagram of a composite electrode preparation device provided in one embodiment of the present application.

[0122] FIG44 is a schematic structural diagram of a composite electrode preparation device provided in one embodiment of the present application.

[0123] DESCRIPTION OF REFERENCE NUMERALS 1. Electrode sheet; 2. Solid electrolyte membrane; 11. Electrode sheet unwinding mechanism; 12. Composite sheet rewinding mechanism; 21. Solid electrolyte membrane unwinding mechanism; 22. Substrate rewinding mechanism; 23. Second solid electrolyte membrane unwinding mechanism; 24. Second substrate rewinding mechanism; 25. First solid electrolyte membrane unwinding mechanism; 26. First substrate rewinding mechanism; 31. First shaping roller; 32. Second shaping roller; 33. Second rigid roller; 34. Second elastic roller; 35. First elastic roller; 36. First rigid roller; 41. Protective film unwinding mechanism; 42. Protective film rewinding mechanism; 51. First guide roller; 52. Second guide roller; 53. Third guide roller; 54. Fourth guide roller; 55. Fifth guide roller; 56. Sixth guide roller; 57. Seventh guide roller; 58. Eighth guide roller; 59. Ninth guide roller; 60. Tenth guide roller; 61. Eleventh guide roller; 62. Twelfth guide roller; 63. Thirteenth guide roller; 71. First heating roller; 72. Second heating roller; 73. Third heating roller; 74. Cooling roller; 75. First cooling roller; 76. Second cooling roller; 77. First heater; 78. Second heater; 79. Fourth heating roller; 81. Glue layer. DETAILED DESCRIPTION

[0124] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0125] In the description of this application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0126] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of this application, if the term "plurality" appears, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0127] In this application, unless otherwise specified or limited, the terms "mounted," "connected," "connected," "fixed," etc., should be interpreted broadly. For example, these terms may refer to fixed connections, removable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediary; and internal communication between two components or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0128] In this application, unless otherwise expressly specified or limited, if a first feature is described as being "above" or "below" a second feature, or similar descriptions, this may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is described as being "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is described as being "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0129] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only embodiment.

[0130] The direction parallel to the running direction of the electrode is defined as the longitudinal direction, and the direction perpendicular to the running direction of the electrode is defined as the transverse direction.

[0131] As shown in Figures 4-5, the composite electrode sheet preparation device of the present application includes shaping rollers, an electrode sheet unwinding mechanism, a solid electrolyte membrane unwinding mechanism, and a composite electrode sheet winding mechanism. The shaping rollers include a first shaping roller and a second shaping roller symmetrically arranged on both sides of the electrode sheet. It can be understood that each pair of the first shaping roller and the second shaping roller constitutes a shaping roller assembly; as a preferred arrangement, 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 sheet, that is, the conveying direction of the electrode sheet is perpendicular to the plane where the axes of the first shaping roller and the second shaping roller are located, but this is not limited to this. The conveying direction of the electrode sheet can be adaptively adjusted according to actual production needs.

[0132] The electrode sheet unwinding mechanism is located upstream of the shaping roller and is used to unwind the electrode sheet and then transport the electrode sheet so that the electrode sheet passes through the gap between the first shaping roller and the second shaping roller.

[0133] The solid electrolyte membrane unwinding mechanism is located upstream of the sizing roller, more specifically, between the electrode sheet unwinding mechanism and the sizing roller. The solid electrolyte membrane unwinding mechanism is used to unwind the solid electrolyte membrane and then transport the solid electrolyte membrane so that the solid electrolyte membrane passes through the gap between the first sizing roller and the second sizing roller. More specifically, the solid electrolyte membrane unwinding mechanism allows the solid electrolyte membrane to pass between the electrode sheet and the sizing roller.

[0134] The composite electrode sheet winding mechanism is located downstream of the shaping roller, and is used to provide tension to the electrode sheet along the direction of movement of the electrode sheet, and to receive the composite electrode sheet obtained after being rolled by the shaping roller to complete the winding action.

[0135] In some embodiments, there is one solid electrolyte membrane unwinding mechanism, which is arranged on one side of the electrode sheet unwinding mechanism. The solid electrolyte membrane unwinding mechanism unwinds and then transports the solid electrolyte membrane so that the solid electrolyte membrane passes through the gap between the first shaping roller and the second shaping roller, so that the solid electrolyte membrane is compounded on one side of the electrode sheet; in some embodiments, there are two solid electrolyte membrane unwinding mechanisms, which are respectively located on both sides of the electrode sheet unwinding mechanism. The solid electrolyte membrane unwinding mechanism unwinds and then transports the solid electrolyte membrane so that the two layers of solid electrolyte membrane pass through the gap between the first shaping roller and the second shaping roller, respectively, and the electrode sheet is located between the two layers of solid electrolyte membrane.

[0136] Optionally, two solid electrolyte membrane unwinding mechanisms are symmetrically arranged on both sides of the electrode plate unwinding mechanism.

[0137] In some embodiments, the composite electrode preparation device further includes a substrate winding mechanism.

[0138] When a substrate is placed on the solid electrolyte membrane, it covers the side of the solid electrolyte membrane away from the electrode sheet. After the electrode sheet and solid electrolyte membrane are rolled together by the sizing rollers to form a composite electrode sheet, the substrate needs to be separated. Separation of the substrate from the composite electrode sheet is achieved by placing a substrate reel downstream of the sizing rollers. During the separation process, the substrate reel applies tension to the solid electrolyte membrane substrate, separating it from the composite electrode sheet and reeling it in when necessary.

[0139] The number of substrate winding mechanisms corresponds to the number of solid electrolyte membrane unwinding mechanisms.

[0140] In some embodiments, an elastic member is provided between the first shaping roller and the second shaping roller.

[0141] The yield limit of the elastic member satisfies the following conditions: when the solid electrolyte membrane and the electrode plate pass through the gap between the shaping rollers, the solid electrolyte membrane and the electrode plate undergo plastic deformation, while the deformation of the elastic member undergoes elastic deformation.

[0142] Elastic deformation refers to the change in the relative positions of points on a solid due to the action of external force. When the external force is removed, the solid returns to its original shape, which is called elastic deformation.

[0143] When an object is subjected to a large force outside its elastic limit, it may break, deform, and be unable to return to its original shape. This phenomenon is called plastic deformation.

[0144] The width of the elastic member is greater than or equal to the minimum thickness of the solid electrolyte membrane or the electrode plate.

[0145] The present application improves the interlayer bonding strength between the solid electrolyte membrane and the electrode plate membrane by means of the plastic deformation formed between the two.

[0146] It can be understood that, on the basis of meeting the above conditions, this application has no special requirements for the rolling pressure. The corresponding rolling pressure selected according to different material systems should still be considered within the scope of protection of this application. It is only used as an illustrative example, not a limitation on the scope of protection. The rolling pressure is 10-1000MPa.

[0147] During the production of electrode sheets, the edges of the electrode sheets are usually thinned to ensure smooth rolling of the subsequent rolling process. However, the presence of the thinned areas of the electrode sheets affects the fit between the solid electrolyte membrane and the electrode sheets.

[0148] Surprisingly, the composite electrode preparation device of the present application uses the buffer provided by the elastic parts during rolling, so that the solid electrolyte membrane can better cover the electrode electrode; at the same time, during the rolling process of the shaping roller, the electrode electrode is thick in the middle, resulting in the force in the middle area of ​​the electrode electrode being greater than the edge area, and the lateral thickness of the electrode electrode tends to be consistent after rolling.

[0149] In some embodiments, the thickness of the solid electrolyte membrane is 1-30 μm; preferably, 3-20 μm; more preferably, 3-15 μm.

[0150] Applying a solid electrolyte coating to the electrode surface, especially the high-capacity positive electrode, can effectively improve battery safety. However, due to energy density limitations, the thickness of the solid electrolyte membrane is typically thin. Compared with dry-process electrode sheets, the thickness of the solid electrolyte membrane is an order of magnitude smaller, making the solid electrolyte membrane susceptible to cracking during dry-process composite electrode sheets.

[0151] The elastic part is made of a flexible material, which undergoes elastic deformation under pressure. The tiny elastic deformation makes the thickness of the middle area and the thinned area of ​​the electrode plate tend to be consistent under pressure, so that it can better fit with the solid electrolyte membrane.

[0152] In some embodiments of the present application, the flexible material is a polymer.

[0153] The present application does not impose any special restrictions on the material of the polymer. For example, it can be plastics such as polytetrafluoroethylene, polyethylene terephthalate, polypropylene, polyacrylonitrile, etc., or rubbers such as Hypalon rubber, silicone rubber, fluororubber, etc., or elastic materials such as silicone that can undergo a certain degree of deformation.

[0154] The present application does not particularly limit the thickness of the elastic member. Any necessary adjustment to the thickness of the elastic member without violating the inventive concept of the present application can be understood as being within the scope of protection of the present application.

[0155] In some embodiments, the elastic member is arranged corresponding to the solid electrolyte membrane. For example, when one side of the electrode plate is composited with a solid electrolyte membrane, the elastic member is arranged in the gap between the shaping roller close to the side of the solid electrolyte membrane and the solid electrolyte membrane. When both sides of the electrode plate are composited with a solid electrolyte membrane, the elastic member is arranged in the gap between the two shaping rollers and the solid electrolyte membrane on the corresponding side.

[0156] In some embodiments, the elastic member is a rubber layer that surrounds and covers the outer sides of the two shaping rollers.

[0157] In some embodiments, the elastic member is a protective film, and the protective film is transported through the gap between the sizing roller and the solid electrolyte membrane.

[0158] Adaptively, the composite electrode sheet preparation apparatus of the present application further includes a protective film unwinding mechanism for unwinding the protective film. The protective film unwinding mechanism is located upstream of the sizing roller and disposed between the solid electrolyte membrane unwinding roller and the sizing roller. During the roll-pressing and laminating process of the electrode sheet and the solid electrolyte membrane, the protective film is located in the gap between the sizing rollers and between the sizing rollers and the solid electrolyte membrane.

[0159] This application does not have any particular requirements for the structure of the protective film. Any known film capable of undergoing a certain degree of elastic deformation under a certain pressure can be used in this application, provided that it does not violate the inventive concept of this application. These examples are provided for illustrative purposes only and are not intended to limit the scope of protection. The protective film can be selected from polymer films or non-woven fabrics, including but not limited to PP-based non-woven fabrics, PE-based non-woven fabrics, PET-based non-woven fabrics, PAN-based non-woven fabrics, PTFE-based non-woven fabrics, and Celgard non-woven fabrics. The polymer film can be selected from PVDF film, PE film, PP film, PE / PP film, PE / PP / PE film, PP / PE / PP film, PTFE film, silicone oil release film, fluorine release film, PET film, and non-silicone release film. It is understood that the protective film can also be a multilayer structure composed of two or more layers of polymer films and / or non-woven fabrics.

[0160] This application does not specifically limit the thickness of the protective film. Without violating the inventive concept of this application, any conventional adjustment of the thickness of the protective film for adjusting the rolling effect should be considered within the scope of protection of this application. It can be understood that when the protective film is a multi-layer structure, the thickness of the protective film should be the sum of the multi-layer structure.

[0161] In some embodiments, the composite electrode sheet preparation apparatus further includes a protective film winding mechanism. The protective film winding mechanism is located downstream of the shaping roller and disposed between the shaping roller and the composite electrode sheet winding mechanism, and is used to provide tension to the protective film and receive the protective film.

[0162] In some embodiments, the composite pole piece preparation apparatus further includes a guide roller.

[0163] Optionally, a guide roller is located between the solid electrolyte membrane unwinding mechanism and the shaping roller to provide guidance for the solid electrolyte membrane. A guide roller can also be provided between the shaping roller and the substrate winding mechanism to provide guidance for the substrate of the solid electrolyte membrane separated from the composite electrode sheet.

[0164] Optionally, a guide roller is located between the protective film unwinding mechanism and the shaping roller to provide a guide for the protective film. A guide roller can be provided between the shaping roller and the protective film winding mechanism to provide a guide for the protective film recovery.

[0165] In some embodiments, the composite electrode preparation device also includes an unwinding correction component, an electrode anti-static component, etc., which are arranged in sequence along its own unwinding route. The unwinding correction component can correct the unwinding and running routes of the electrode electrode and the solid electrolyte membrane, etc., so that the starting material line remains at the same level. The winding and unwinding mechanism of the main material adopts a single-station correction, and the winding and unwinding of the remaining materials adopt a cantilever type, all with correction. The anti-static component performs anti-static treatment on both sides of the electrode electrode, which can reduce the friction between the electrode and the conveying roller. It can be understood that, without violating the inventive concept of the present application, in the entire process from winding, rolling, and unwinding, known functional components or structures can be used in the present application.

[0166] In some embodiments, the width of the sizing roller is 500-800 mm, including but not limited to 500 mm, 550 mm, 600 mm, 650 mm, 700 mm, 750 mm, and 800 mm, preferably 550-650 mm.

[0167] In some embodiments, the diameter of the shaping roller is 300-500 mm, including but not limited to 300 mm, 350 mm, 400 mm, 450 mm, and 500 mm, preferably 350-450 mm.

[0168] 4-5 , in combination with the structure of the composite electrode sheet preparation device, the composite electrode sheet preparation method of the present application includes the following steps: unwinding the electrode sheet through the electrode sheet unwinding mechanism 11 and conveying the electrode sheet to the composite electrode sheet winding mechanism 12, so that the electrode sheet passes through the gap between the first shaping roller 31 and the second shaping roller 32; conveying the solid electrolyte membrane through the solid electrolyte membrane unwinding mechanism 21 located on the side of the electrode sheet unwinding mechanism 11, so that the solid electrolyte membrane passes through the gap between the shaping roller and the electrode sheet; then the electrode sheet and the solid electrolyte membrane are roll-compounded by the first shaping roller 31 and the second shaping roller 32; during the rolling compounding, an elastic member is arranged between the shaping roller and the solid electrolyte membrane; finally, downstream of the shaping roller, the composite electrode sheet is received by the composite electrode sheet winding mechanism 12.

[0169] In some embodiments, a composite electrode sheet includes an electrode sheet and solid electrolyte membranes located on either side of the electrode sheet. After transporting the electrode sheet, two solid electrolyte membrane unwinding mechanisms 21 located on either side of the electrode sheet unwinding mechanism 11 unwind the solid electrolyte membrane and convey the solid electrolyte membrane to shaping rollers, causing the two layers of solid electrolyte membrane to 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 membrane, the electrode sheet located between the two layers of solid electrolyte membrane, and the elastic members located outside the two layers of solid electrolyte membrane are bonded to each other. Under the rolling action of the shaping rollers, the solid electrolyte membranes are bonded to both sides of the electrode sheet, thereby forming a composite electrode sheet.

[0170] In some embodiments, the solid electrolyte membrane is formed independently, meaning that the solid electrolyte membrane can be formed and maintained intact without the aid of a substrate. In this case, after the electrode sheet and solid electrolyte membrane enter the gap between the sizing rollers, the pressure of the sizing rollers forms a composite electrode sheet, which is then wound using the electrode sheet winding mechanism.

[0171] In some embodiments, the solid electrolyte membrane is covered with a substrate to provide support for the solid electrolyte membrane. The solid electrolyte membrane unwinding mechanism 21 conveys the solid electrolyte membrane so that the substrate is located on the side of the solid electrolyte membrane away from the electrode sheet. After the solid electrolyte membrane and the electrode sheet are fully composited, the substrate is separated from the composite electrode sheet. Specifically, the substrate rewinding mechanisms 22 located on both sides of the composite electrode sheet rewinding mechanism 12 each receive the substrate, with the substrate rewinding mechanisms 22 located between the sizing roller and the composite electrode sheet rewinding mechanism 12.

[0172] In some embodiments, the elastic member is a rubber layer that surrounds and covers the outside of the first and second shaping rollers 31 and 32. As the shaping rollers rotate, the rubber layer rotates with them. Furthermore, as the shaping rollers press the solid electrolyte membrane and / or electrode sheets, the rubber layer provides a cushioning effect on the solid electrolyte membrane and / or electrode sheets, allowing the solid electrolyte membrane to better cover one or both sides of the electrode sheets and improving the consistency of the transverse thickness of the electrode sheets after pressing.

[0173] In some embodiments, the elastic member is a protective film. The protective film can be unwound by two protective film unwinding mechanisms 41 located on the side of the solid electrolyte membrane unwinding mechanism 21 away from the electrode sheet. The protective film unwinding mechanisms 41 convey the protective film to the shaping rollers so that the two layers of protective film 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 protective film, solid electrolyte membrane, electrode sheet, solid electrolyte membrane, and protective film, which are sequentially distributed, are laminated in pairs. Under the rolling action of the shaping rollers, the solid electrolyte membrane is composited on both sides of the electrode sheet, thereby forming a composite electrode sheet.

[0174] Alternatively, as shown in Figure 4, the solid electrolyte membrane and protective film are guided by guide rollers 51 and 52, respectively, before arriving between the first and second shaping rollers 31 and 32. The first guide roller 51 is located on the side of the second guide roller 52 away from the shaping rollers. The protective film and solid electrolyte membrane rotate together toward the shaping rollers, contacting the electrode pole piece and passing through the gap between the first and second shaping rollers 31 and 32, more specifically, between the shaping rollers and the electrode pole piece. Subsequently, under the pressure of the first and second shaping rollers 31 and 32, the electrode pole piece and the two layers of solid electrolyte membrane are bonded.

[0175] Alternatively, the solid electrolyte membrane and the protective film may be laminated upstream of the shaping rollers, and then contact the electrode sheets as the shaping rollers rotate. For example, the protective film is laminated to the side of the solid electrolyte membrane away from the electrode sheets at the second guide roller 52. The solid electrolyte membrane and the protective film then rotate together 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. The side of the solid electrolyte membrane away from the protective film then contacts and laminates with the electrode sheets.

[0176] During rolling, the shaping roller applies tension to the electrode sheet and the solid electrolyte membrane, and the two layers of protective film are located between the shaping roller and the solid electrolyte membrane, which play a buffering role, so that the force applied to each site of the electrode sheet and the solid electrolyte membrane is relatively uniform. Finally, the solid electrolyte membrane in the composite sheet almost completely covers the electrode sheet, the bonding between the electrode sheet and the solid electrolyte membrane is better, the consistency of the lateral thickness of the composite sheet is improved, and the compaction density is also improved.

[0177] In some embodiments, the protective film and the substrate can be separated from the composite pole piece at the same time.

[0178] When there is only one guide roller 53 downstream of the shaping roller, after the shaping roller is rolled, the composite electrode continues to be conveyed downstream of the shaping roller 32. The protective film and the substrate rotate together with the shaping roller under the action of the protective film winding mechanism 42 and the substrate winding mechanism 22 respectively, and then reach the third guide roller 53. Then, the protective film and the substrate begin to separate after rotating around the third guide roller 53 for a certain angle. The protective film moves forward toward the protective film winding mechanism 42 and completes the winding action, and the substrate moves forward toward the substrate winding mechanism 22 and completes the winding action.

[0179] When there are two guide rollers 53 and 54 downstream of the shaping roller, after the shaping roller is rolled, the composite electrode continues to be transported downstream of the shaping roller 32. The protective film and the substrate are respectively rotated along with the shaping roller under the action of the protective film winding mechanism 42 and the substrate winding mechanism 22, and then reach the third guide roller 53 and the fourth guide roller 54 respectively. Then the protective film moves forward to the protective film winding mechanism 42 and completes the winding action, and the substrate moves forward to the substrate winding mechanism 22 and completes the winding action.

[0180] Alternatively, the guide roller 53 may be replaced by two or more guide rollers; the guide roller 54 may be replaced by two or more guide rollers.

[0181] In some embodiments, the protective film may also be separated from the composite electrode sheet before the substrate. After being rolled by the shaping roller, the composite electrode sheet continues to be conveyed downstream of the shaping roller 32. Under the action of the protective film winding mechanism 42, the protective film rotates along with the shaping roller and reaches the third guide roller 53. After rotating around the third guide roller 53 for a certain angle, the protective film continues to move forward toward the protective film winding mechanism 42 and completes the winding action. After the substrate leaves the shaping roller and is conveyed along with the composite electrode sheet for a certain distance, the substrate is separated from the composite electrode sheet by the substrate winding mechanism 22 and reaches the fourth guide roller 54. After rotating around the fourth guide roller 54 for a certain angle, the substrate continues to move forward toward the protective film winding mechanism 42 and completes the winding action.

[0182] In some embodiments, the solid electrolyte membrane starts from the solid electrolyte membrane unwinding mechanism and can be guided to the shaping roller by the guide roller. The number of guide rollers includes but is not limited to 1, 2, 3, 4, 5 or more. The specific number can be increased or decreased according to actual conditions, preferably 1 or 2 guide rollers.

[0183] When the substrate of the solid electrolyte membrane is recovered, it can be guided and transported to the substrate winding mechanism through guide rollers. The number of guide rollers includes but is not limited to 1, 2, 3, 4, 5 or more, preferably 1 guide roller.

[0184] The protective film can be guided from the protective film winding mechanism to the shaping roller via a guide roller, and the number of guide rollers includes but is not limited to 1, 2, 3, 4, 5 or more, preferably 1 or 2 guide rollers.

[0185] When the protective film is recovered, it can be guided and transmitted to the protective film winding mechanism through guide rollers. The number of guide rollers includes but is not limited to 1, 2, 3, 4, 5 or more, preferably 1 or 2 guide rollers.

[0186] Optionally, in the process of conveying the solid electrolyte membrane and the protective membrane to the shaping roller, some or all of the guide rollers may be shared.

[0187] In some embodiments, the mechanical speed of the sizing roller is 5-60 m / min, including but not limited to 5 m / min, 10 m / min, 20 m / min, 30 m / min, 40 m / min, 45 m / min, 50 m / min, and 60 m / min.

[0188] It is understandable that higher speeds for the composite electrode sheet preparation apparatus result in higher production efficiency, but excessively high speeds can easily lead to problems such as electrode sheet and solid electrolyte membrane breakage. This application does not specifically require the residence time of the electrode sheet and solid electrolyte membrane within the gap between the sizing rollers. Adjustments to the residence time that do not require inventive effort, provided they do not violate the inventive concept of this application, should be understood to fall within the scope of protection of this application.

[0189] In some embodiments, the linear speeds of the first shaping roller and the second shaping roller are kept consistent, and the linear speeds of the electrode sheet unwinding mechanism and the linear speed of the composite sheet winding mechanism are also kept consistent, thereby improving the consistency of the entire composite sheet rolling preparation process and improving the consistency of the composite sheet.

[0190] In some embodiments, the linear speeds of the first and second shaping rollers are different, and the rolling effect can be adjusted by setting the first and second shaping rollers at different speeds.

[0191] In some embodiments, a heating unit is provided inside the sizing roller, and the temperature range of the sizing roller is 100-300°C, including but not limited to 100°C, 150°C, 200°C, 250°C, and 300°C, preferably 150-200°C.

[0192] Referring to Figure 1, which illustrates a flow chart of the method for preparing a composite electrode sheet using the aforementioned composite electrode sheet preparation apparatus, the present application first positions a solid electrolyte membrane on one or both sides of an electrode sheet. The electrode sheet and the solid electrolyte membrane then pass through the gap between sizing rollers under dry conditions, and are rolled under the action of an elastic member to produce a composite electrode sheet. The elastic member is used to adjust the force applied to the electrode sheet and the solid electrolyte membrane during the rolling process, allowing the solid electrolyte membrane to better cover the electrode sheet. Furthermore, after rolling, the lateral thickness of the electrode sheet tends to be consistent.

[0193] 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 located on both sides of the electrode sheet, which means that both sides of the electrode sheet are composited with the solid electrolyte membrane by the rolling roller.

[0194] In some embodiments, the elastic member is a protective film. During rolling, the protective film is arranged in the gap between the shaping roller and the solid electrolyte membrane. As shown in Figures 4-5, a protective film, a solid electrolyte membrane, an electrode plate, a solid electrolyte membrane 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 the gap between the shaping roller and the solid electrolyte membrane and is rolled, and then continues to run downstream of the shaping roller until it is recycled. Therefore, the protective film of the present application can be reused, saving production and manufacturing costs while reducing damage to the environment, and is also conducive to improving production efficiency.

[0195] In some embodiments, the protective film can be recovered downstream of the sizing roller by separating the protective film from the composite pole piece.

[0196] In some embodiments, the elastic member is a rubber layer that wraps around and covers the outside of the sizing roller. As shown in Figure 5 , the rubber layer, solid electrolyte membrane, electrode sheet, solid electrolyte membrane, and rubber layer are sequentially arranged between the sizing rollers. The rubber layer can extend slightly longer than the axial length of the sizing rollers, and during rolling, the rubber layer rotates with the sizing rollers.

[0197] The composite process of this application is carried out under dry conditions. This dry process is different from the traditional wet electrode preparation method. The traditional wet method of preparing composite electrodes is to first prepare a solid electrolyte slurry and then apply the solid electrolyte slurry to the electrode plate, or vice versa, to prepare an electrode slurry and then apply the electrode slurry to the solid electrolyte membrane. The preparation process of this application does not use solvents, eliminating the tedious subsequent drying step, which can effectively reduce production costs.

[0198] It can be understood that the dry process means that no solvent is added during the preparation of the relevant electrode plates and electrolyte membranes; the technical solutions of trace amounts of liquid lubricants or other liquid additives that may be used during the rolling process should still be within the scope of protection of this application.

[0199] In some embodiments, the electrode plates and the solid electrolyte membrane are both prepared by a dry process.

[0200] In some embodiments, at least one of the electrode sheet and the solid electrolyte membrane is prepared by a dry process.

[0201] In some embodiments, the electrode plates and the solid electrolyte membrane are both prepared by a wet process.

[0202] It is understandable that the electrode plates and solid electrolyte membranes are preferably prepared under dry conditions, so that no solvent is required during the entire electrode preparation process.

[0203] It is understandable that the preparation process of the electrode sheet and the solid electrolyte membrane is independent of the preparation process of the composite electrode, that is, if a wet process is used, the electrode sheet undergoes coating, drying, and rolling processes.

[0204] In some embodiments, the electrode plate is a positive electrode plate. Positive electrode materials, especially high-nickel ternary materials with high energy density, are prone to undesirable side reactions with electrolytes, especially non-aqueous electrolytes. Such side reactions can cause a decrease in battery performance and pose potential safety hazards. Composite solid electrolyte layers on the positive electrode surface can help improve battery safety.

[0205] The positive electrode sheet comprises an active material layer and a current collector layer. During dry-process preparation of the positive electrode sheet, the active material, conductive agent, and binder are first stirred to produce a positive electrode mixture. This mixture is then subjected to a fiberization treatment to produce a fiberized positive electrode mixture. The fiberized positive electrode mixture is then rolled and laminated with the current collector layer to produce the positive electrode sheet. In some embodiments, fiberization methods include, but are not limited to, airflow milling, high-speed stirring, mechanical fusion, and twin-screw extrusion.

[0206] 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.

[0207] The positive electrode active material is one of a layered oxide, a spinel and a polyanion. For example, the 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 LiCoO2 (LCO), LiNi x Mn y Co 1-x-y O2 (where 0≤x≤1 and 0≤y≤1), LiNi 1-x-y Co x Al y O2 (where 0≤x≤1 and 0≤y≤1), LiNi x Mn 1-x O2 (where 0≤x≤1), and Li 1+x MO2 (wherein M is one of Mn, Ni, Co and Al and 0≤x≤1). The spinel comprises one or more lithium-based positive active materials selected from the group consisting of LiMn2O4 (LMO) and LiNi x Mn 1.5 O4. Olivine type contains one or more lithium-based positive active materials LiMPO4 (wherein M is at least one of Fe, Ni, Co and Mn). The polyanion cation contains, for example, phosphates such as LiV2(PO4)3 and / or silicates such as LiFeSiO4.

[0208] In some embodiments, one or more lithium-based positive electrode active materials may be optionally coated (e.g., by LiNbO3 and / or Al2O3) and / or may be doped (e.g., by magnesium (Mg)). In addition, in certain embodiments, one or more lithium-based positive electrode active materials may be optionally mixed with one or more conductive materials that provide an electron conduction path and / or at least one polymer binder material that improves the structural integrity of the positive electrode. For example, the positive electrode active material layer may comprise greater than or equal to about 30 wt% to less than or equal to about 99 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.

[0209] In some embodiments, the binder includes 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.

[0210] 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 particles of, for example, carbon black, graphite, acetylene black (e.g., KETCHEN™ black or DENKA™ black), carbon fibers and nanotubes, graphene, etc. Examples of conductive polymers include polyaniline, polythiophene, polyacetylene, polypyrrole, etc.

[0211] It should be understood that the above examples of positive electrode active materials, binders, and conductive materials are merely illustrative. Any known positive electrode active materials, binders, and conductive materials may be used in this application without violating the inventive concept of this application. Furthermore, the addition of known additives based on actual usage requirements should also be considered within the scope of protection of this application.

[0212] In some embodiments, both the front and back sides of the current collector layer include active material layers.

[0213] In some embodiments, the current collector layer may be a metal foil or a composite current collector.

[0214] For example, the metal foil may be aluminum foil.

[0215] The composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer.

[0216] Research has shown that wet coating, a common method used in conventional technologies, often creates ridges at the edges of the active material layer during the drying process due to the fluidity and surface tension of the positive electrode active material slurry, as it is a water-based slurry. Furthermore, during roller pressing, these ridges can directly cause cracks at the edges of the active material layer due to the force exerted by the roller, leading to cracking in the positive electrode active material layer and ultimately affecting battery performance. Furthermore, wet coating can potentially cause swelling and rapid performance degradation during long-term battery cycling due to excessive moisture content.

[0217] In some embodiments, the electrode pad is a negative electrode pad.

[0218] The negative electrode sheet is formed of a lithium-based material capable of serving as a negative terminal for a lithium-ion battery (e.g., a negative electrode active material). In various aspects, the negative electrode sheet can be defined by a plurality of negative electrode active material particles. Such negative electrode active material particles can be arranged in one or more layers to define the three-dimensional structure of the negative electrode. In certain embodiments, the negative electrode may further include an electrolyte 50, such as a plurality of electrolyte particles (not shown).

[0219] In some embodiments, the negative electrode sheet may include a lithium-based negative active material, which includes, for example, lithium metal and / or lithium alloy.

[0220] The negative electrode sheet may be a silicon-based negative electrode active material, which includes, for example, a silicon alloy, silicon oxide, or a combination thereof, and in some cases may also be mixed with graphite.

[0221] The negative electrode sheet may be a carbonaceous-based negative electrode active material comprising one or more of graphite, graphene, carbon nanotubes (CNTs), and combinations thereof.

[0222] The negative electrode sheet may also include one or more negative electrode active materials that accept lithium, such as lithium titanium oxide (Li4Ti5O 12 ), one or more transition metals (e.g., tin (Sn)), one or more metal oxides (e.g., vanadium oxide (V2O5), tin oxide (SnO), titanium dioxide (TiO2)), titanium niobium oxide (TixNbyOz, where 0≤x≤2, 0≤y≤24 and 0≤z≤64), metal alloys (such as copper tin alloy (Cu6Sn5)) and one or more metal sulfides (such as iron sulfide (FeS)).

[0223] Alternatively, the negative electrode 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 polymer binder material that improves the structural integrity of the negative electrode. For example, the negative electrode active material may be doped with a binder such as poly(tetrafluoroethylene) (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. The conductive material may include carbon-based materials, powdered nickel or other metal particles or conductive polymers. The carbon-based material may include, for example, particles of carbon black, graphite, superP, acetylene black (such as KETCHEN™ black or DENKA™ black), carbon fibers and nanotubes, graphene, and the like. Examples of the conductive polymer include polyaniline, polythiophene, polyacetylene, polypyrrole, poly(3,4-ethylenedioxythiophene) polystyrene sulfonate, and the like.

[0224] The negative electrode sheet may include greater than or equal to about 50 weight % to less than or equal to about 99 weight % of a negative electrode active material, optionally greater than or equal to about 0 weight % to less than or equal to about 60 weight % of a solid electrolyte, optionally greater than or equal to about 0 weight % to less than or equal to about 15 weight % of a conductive material, and optionally greater than or equal to about 0 weight % to less than or equal to about 10 weight % of a binder.

[0225] As mentioned in the background technology, the dry preparation method is that the traditional shaping roller has high strength and poor deformation resistance, and the electrode plate is chamfered to ensure the smooth rolling process, forming a structure that is thick in the middle and thin at both ends. As shown in Figure 2, due to the inconsistent lateral thickness of the electrode plate 1, when the solid electrolyte membrane 2 is attached to the electrode plate 1, the edge area of ​​the electrode plate 1 is still separated from the solid electrolyte membrane. When the rolling equipment rolls the electrode plate 1 and the solid electrolyte membrane 2 for composite, the middle area and the edge area of ​​the electrode plate 1 are subjected to different rolling forces of the steel roller, making it difficult for the electrode plate 1 and the solid electrolyte membrane 2 to be tightly composited, that is, invalid composite, resulting in inconsistent lateral compaction density of the composite plate, and poor consistency of the composite plate. In severe cases, the electrode plate may break, which has a great impact on the safety performance and quality of the lithium-ion battery.

[0226] The preparation method of the present application utilizes the buffer provided by the elastic member during the rolling of the shaping roller so that the solid electrolyte membrane can better cover the electrode plate; at the same time, during the rolling process of the shaping roller, the electrode plate is thick in the middle, resulting in a greater force in the middle area of ​​the electrode plate than in the edge area. After rolling, the lateral thickness of the electrode plate tends to be consistent as shown in Figure 3, which is an effective composite. This avoids the adverse effects of the rolling composite process caused by the phenomenon that the electrode plate 1 is thick in the middle and thin at both ends, protects the electrode plate 1 from being crushed, and can also better combine the active material layer in the electrode plate 1 with the solid electrolyte membrane 2. In addition, during the rolling process of the shaping roller, the electrode plate 1 and the solid electrolyte membrane 2 can be pressed evenly under force, which improves the compaction density of the composite plate, ensures the consistency of the thickness of the composite plate, weakens the phenomenon that the electrode plate 1 is thick in the middle and thin at both ends, improves the quality of continuous rolling, and can be used for large-scale production.

[0227] In some embodiments, a solid electrolyte membrane includes a solid electrolyte and a binder.

[0228] When preparing a solid electrolyte membrane, a solid electrolyte and a binder are first stirred and mixed, and the mixture is subjected to fiberization treatment to obtain a fiberized solid electrolyte mixture, which is then rolled to obtain a solid electrolyte membrane.

[0229] In some embodiments, the solid electrolyte is an inorganic solid electrolyte, including one or more of an oxide solid electrolyte, a sulfide solid electrolyte, a halide solid electrolyte, a hydride solid electrolyte, a boride solid electrolyte, and a nitride solid electrolyte.

[0230] The oxide solid electrolyte comprises one or more garnet ceramics, LISICON type oxides, NASICON type oxides and perovskite type ceramics. For example, one or more garnet ceramics include but are not limited to Li 6.5 La3Zr 1.75 Te 0.25 O 12 、Li7La3Zr2O 12 、Li 6.2 Ga 0.3 La 2.95 Rb 0.05 Zr2O 12 、Li 6.85 La 2.9 Ca 0.1 Zr 1.75 Nb 0.25 O 12 、Li 6.25 Al 0.25 La3Zr2O 12 、Li 6.75 La3Zr1.75 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(GeO4)4, Li 3+x (P 1-x Si x )O4 (where 0 < x < 1), Li 3+x Ge x V 1-x O4 (where 0 < x < 1). One or more NASICON-type oxides can be defined by LiMM′(PO4)3, where M and M′ are independently selected from Al, Ge, Ti, Sn, Hf, Zr, and La. For example, in certain variations, one or more NASICON-type oxides include, but are not limited to, Li 1+x Al x Ge 2-x (PO4)3 (LAGP) (where 0 ≤ x ≤ 2), Li 1+x Al x Ti 2-x (PO4)3 (LATP) (where 0 ≤ x ≤ 2), Li 1+x Y x Zr 2-x (PO4)3 (LYZP) (where 0 ≤ x ≤ 2), Li 1.3 Al 0.3 Ti 1.7 (PO4)3, LiTi2(PO4)3, LiGeTi(PO4)3, LiGe2(PO4)3, LiHf2(PO4)3. One or more perovskite-type ceramics include, but are not limited to, Li 3.3 La 0.53 TiO3, LiSr 1.65 Zr 1.3 Ta 1.7 O9, Li 2x-y Sr 1-x Ta y Zr 1-y O3 (where x = 0.75y and 0.60 < y < 0.75), Li 3 / 8 Sr 7 / 16 Nb 3 / 4 Zr 1 / 4 O3, Li 3x La (2 / 3 - x) TiO3 (where 0 < x < 0.25).

[0231] Sulfide solid electrolytes include, but are not limited to, Li2S-P2S5, Li2S-P2S5-MSx (where M is Si, Ge, and Sn and 0≤x≤2), Li 3.4 Si 0.4 P 0.6 S4, Li 10 GeP2S 11.7 O 0.3 、Li 9.6 P3S 12 、Li7P3S 11 、Li9P3S9O3、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 )P2S 12 、Li(Ge 0.5 Sn 0.5 )P2S 12 、Li(Si 0.5 Sn 0.5 )PsS 12 、Li 10 GeP2S 12 (LGPS), Li6PS5X (wherein X is Cl, Br or I), Li7P2S8I, Li 10.35 Ge 1.35 P 1.65 S 12 、Li 3.25 Ge 0.25 P 0.75 S4, Li 10 SnP2S 12 、Li 10 SiP2S 12 、Li 9.54 Si 1.74 P 1.44 S 11.7 C l0.3 、 (1-x) P2S 5-x One or more of Li2S (wherein 0.5≤x≤0.7).

[0232] Halide solid electrolytes include but are not limited to Li2CdC l4 、Li2MgC l4 、Li2Cd I4 , Li2ZnI4, Li3OCl, LiI, Li5ZnI4, Li3OCl 1- xBr x One or more of (where 0 < x < 1).

[0233] The boride solid electrolyte includes, but is not limited to, one or more of Li2B4O7, Li2O-(B2O3)-(P2O5).

[0234] The nitride solid electrolyte includes, but is not limited to, one or more of Li3N, Li7PN4, LiSi2N3, LiPON.

[0235] The hydride solid electrolyte includes, but is not limited to, one or more of Li3AlH6, LiBH4, LiBH4-LiX (where X is one of Cl, Br, and I), LiNH2, Li2NH, LiBH4-LiNH2.

[0236] In some embodiments, the inorganic solid electrolyte can be one or more metal oxide particles or lithium-containing compounds, including, but not limited to, one or more of Al2O3, SiO2, TiO2, LiNbO3, Li4Ti5O4, Li3PO4.

[0237] In some embodiments, the solid electrolyte further includes a partial polymer solid electrolyte.

[0238] A composite solid electrolyte composed of a polymer solid electrolyte and an inorganic solid electrolyte. In the embodiments of the present application, there is no particular requirement for the mass ratio of the inorganic solid electrolyte and the polymer solid electrolyte in the composite solid electrolyte, and the user can design it according to actual needs. Among them, the polymer solid electrolyte can be at least one of polyvinyl chloride (PVC), polyacrylonitrile (PAN), polymethyl methacrylate (PMMA), and polyethylene oxide (PEO).

[0239] In some embodiments, the polymer solid electrolyte contains a lithium salt.

[0240] In some embodiments, the lithium salt includes, but is not limited to, lithium hexafluorophosphate (LiPF6); lithium perchlorate (LiClO4), lithium tetrachloroaluminate (LiAlCl4), lithium iodide (LiI), lithium bromide (LiBr), lithium thiocyanate (LiSCN), lithium tetrafluoroborate (LiBF4), lithium difluorooxalatoborate (LiBF2(C2O4))(LiODFB), lithium tetraphenylborate (LiB(C6H5)4), lithium bis(oxalato)borate (LiB(C2O4)2)(LiBOB), lithium tetrafluorooxalatophosphate (LiPF4(C2O4))(LiFOP), lithium nitrate (LiNO3), lithium hexafluoroarsenate (LiAsF6), lithium trifluoromethanesulfonate (LiCF3SO3), lithium bis(trifluoromethanesulfonyl imide) (LITFSI)(LiN(CF3SO2)2), lithium bis(fluorosulfonyl imide) (LiN(FSO2)2)(LIFSI), and combinations thereof. In certain variations, the lithium salt is selected from one or more of lithium hexafluorophosphate (LiPF6), lithium bis(trifluoromethanesulfonyl imide) (LiTFSI)(LiN(CF3SO2)2), lithium bis(fluorosulfonyl imide) (LiN(FSO2)2)(LiFSI), lithium fluoroalkyl phosphonate (LiFAP), and lithium phosphate (Li3PO4).

[0241] It can be understood that the above-mentioned terms including oxide solid electrolytes, sulfide solid electrolytes, halide solid electrolytes, hydride solid electrolytes, nitride solid electrolytes, polymer solid electrolytes and other materials are all known in the art. The refinement of the above-mentioned materials is only for illustrative purposes and not for limiting the scope of protection. Without violating the inventive concept of this application, any known type of solid electrolyte can be used in this application.

[0242] In some embodiments, the solid electrolyte membrane is formed independently, that is, the solid electrolyte membrane can be formed and maintain integrity without the aid of a substrate.

[0243] In some embodiments, the side of the solid electrolyte membrane away from the electrode plate is covered with a substrate, and the bonding strength between the substrate and the solid electrolyte membrane is weaker than the bonding strength between the solid electrolyte membrane and the electrode plate. After rolling, at least a portion of the solid electrolyte is transferred to the electrode and separated from the substrate.

[0244] The present application does not specifically limit the type of substrate. Without violating the inventive concept of the present application, any known material with a certain supporting effect, which can be more conducive to the film formation of the electrolyte material and can be separated from the solid electrolyte membrane after rolling can be used in the present application; it is only used as an illustrative example, not any limitation on 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 film, PE / PP film, PP / PE / PP film, PE / PP / PE film, and non-silicone release film.

[0245] The present application also provides a composite electrode, which is prepared according to the composite electrode preparation method provided above.

[0246] The present application further provides a lithium-ion battery, which includes the composite electrode provided above.

[0247] In some embodiments, the electrode plates and solid electrolyte membranes may also be purchased.

[0248] In one embodiment of the present application, the following steps are included.

[0249] 1. Preparation of positive electrode sheet

[0250] Lithium manganese oxide is selected as the positive electrode active material, Ketjen black is used as the conductive agent, and PTFE is used as the binder. These materials are mixed and stirred in a high-speed blender to produce a positive electrode mixture. This mixture is then subjected to a jet milling process to fiberize the positive electrode mixture, i.e., the positive electrode active material layer. This positive electrode active material layer is then composited with a current collector by roller pressing to produce a positive electrode sheet.

[0251] 2. Preparation of solid electrolyte membrane

[0252] LATP was selected as the solid electrolyte and polytetrafluoroethylene was selected as the binder. The above substances were mixed and stirred using a high-speed stirrer to obtain a solid electrolyte mixture. The mixture was then fiberized by air jet milling to obtain a fiberized solid electrolyte mixture. The fiberized solid electrolyte mixture was then rolled to obtain a solid electrolyte membrane.

[0253] 3. Preparation of composite positive electrode sheet

[0254] The positive electrode sheet and two layers of solid electrolyte membrane are composited by using a composite electrode sheet preparation device provided with a protective film as shown in Figure 4, so that the solid electrolyte membrane is composited on both sides of the positive electrode active material layer of the positive electrode sheet. The protective film is a PE-based non-woven fabric.

[0255] The solid electrolyte membrane originates from the solid electrolyte membrane unwinding mechanism 21, passes through the first guide roller 51, and arrives at the shaping roller. The protective film originates from the protective film unwinding mechanism, passes through the second guide roller 52, and arrives at the shaping roller. The first guide roller 51 is located on the side of the second guide roller 52 away from the shaping roller. After rotating with the shaping roller, the solid electrolyte membrane and protective film come into contact with the positive electrode sheet and pass through the gap between the first and second shaping rollers, more specifically, through the gap between the shaping roller and the positive electrode sheet. Subsequently, under the pressure of the first and second shaping rollers, the positive electrode sheet and the two layers of solid electrolyte membrane are composited. Under the action of the composite electrode sheet rewinding mechanism 12, the composite electrode sheet advances toward the composite electrode sheet rewinding mechanism 12, where it is received and rewound, resulting in a composite electrode sheet with solid electrolyte membrane composited on both sides of the positive electrode sheet.

[0256] After the protective film and the substrate leave the gap between the first shaping roller 31 and the second shaping roller 32, the protective film and the substrate are separated from the composite electrode and rotate a certain angle with the first shaping roller 31 or the second shaping roller 32. The protective film is received and wound by the protective film winding mechanism via the third guide roller 53; the substrate is received and wound by the solid electrolyte membrane winding mechanism via the 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.

[0257] The thickness of the middle area of ​​the composite pole piece was detected to be 160μm, and the thickness of the edge area was 160μm. There were no cracks on the surface of the composite pole piece when observed with the naked eye, which met the standards for the use of composite pole pieces; the protective film did not undergo obvious deformation.

[0258] In one embodiment of the present application, the following steps are included.

[0259] 1. Preparation of positive electrode sheet

[0260] Lithium manganese oxide is selected as the positive electrode active material, Ketjen black is used as the conductive agent, and PTFE is used as the binder. These materials are mixed and stirred in a high-speed blender to produce a positive electrode mixture. This mixture is then subjected to a jet milling process to fiberize the positive electrode mixture, i.e., the positive electrode active material layer. This positive electrode active material layer is then composited with a current collector by roller pressing to produce a positive electrode sheet.

[0261] 2. Preparation of solid electrolyte membrane

[0262] LGPS was selected as the solid electrolyte, polytetrafluoroethylene as the binder, and LiPF6 as the lithium salt. These materials were mixed and stirred using a high-speed stirrer to produce a solid electrolyte mixture. The mixture was then fiberized using a jet mill to produce a fiberized solid electrolyte mixture. This fiberized solid electrolyte mixture was then rolled to produce a solid electrolyte membrane.

[0263] 3. Preparation of composite positive electrode sheet

[0264] The positive electrode sheet and the two layers of solid electrolyte membrane are composited by a composite electrode sheet preparation device equipped with a protective film, so that the solid electrolyte membrane is composited on the positive electrode active material layers on both sides of the positive electrode sheet. The protective film is a PE-based non-woven fabric.

[0265] The solid electrolyte membrane originates from the solid electrolyte membrane unwinding mechanism, passes through the first and second guide rollers, and then reaches the shaping roller. The protective film originates from the protective film unwinding mechanism, passes through the second guide roller 52, and then reaches the shaping roller. The first guide roller 51 is located on the side of the second guide roller 52 away from the shaping roller. The solid electrolyte membrane and protective film rotate with the shaping roller, contacting the positive electrode sheet and passing through the gap between the first and second shaping rollers, more specifically, between the shaping roller and the positive electrode sheet. The positive electrode sheet and the two layers of solid electrolyte membrane are then laminated under the pressure of the first and second shaping rollers. The composite electrode sheet advances toward the composite electrode sheet rewinding mechanism under the action of the composite electrode sheet rewinding mechanism, where it is received and rewound by the composite electrode sheet rewinding mechanism 12, resulting in a composite electrode sheet with solid electrolyte membrane laminated on both sides of the positive electrode sheet.

[0266] After the protective film and the substrate leave the gap between the first shaping roller and the second shaping roller, the protective film and the substrate are separated from the composite electrode and rotate a certain angle with the first shaping roller or the second shaping roller. Then, the protective film and the substrate are respectively conveyed to the third guide roller under the action of the protective film winding mechanism and the substrate winding mechanism 22, and the protective film and the substrate are separated after rotating around the third guide roller at a certain angle. The protective film is received and wound by the protective film winding mechanism 42, and the substrate is received and wound by the substrate winding mechanism 22.

[0267] The thickness of the middle area of ​​the composite pole piece was detected to be 190μm, and the thickness of the edge area was 190μm. There were no cracks on the surface of the composite pole piece when observed with the naked eye, which met the use standards of the composite pole piece; the protective film did not undergo obvious deformation.

[0268] In one embodiment of the present application, the following steps are included.

[0269] 1. Preparation of positive electrode sheet

[0270] Lithium manganese oxide is selected as the positive electrode active material, Ketjen black is used as the conductive agent, and PTFE is used as the binder. These materials are mixed and stirred in a high-speed blender to produce a positive electrode mixture. This mixture is then subjected to a jet milling process to fiberize the positive electrode mixture, i.e., the positive electrode active material layer. This positive electrode active material layer is then composited with a current collector by roller pressing to produce a positive electrode sheet.

[0271] 2. Preparation of solid electrolyte membrane

[0272] LATP was selected as the solid electrolyte and polytetrafluoroethylene was selected as the binder. The above substances were mixed and stirred using a high-speed stirrer to obtain a solid electrolyte mixture. The mixture was then fiberized by air jet milling to obtain a fiberized solid electrolyte mixture. The fiberized solid electrolyte mixture was then rolled to obtain a solid electrolyte membrane.

[0273] 3. Preparation of composite positive electrode sheet

[0274] The positive electrode sheet and the two layers of solid electrolyte membranes are compounded by a roller press provided with a glue layer as shown in FIG5 , so that the solid electrolyte membranes are simultaneously compounded on the positive electrode active material layers on both sides of the positive electrode sheet.

[0275] The solid electrolyte membrane starts from the solid electrolyte membrane unwinding mechanism, passes through the first guide roller, and then reaches the shaping roller. After rotating with the shaping roller, the solid electrolyte membrane contacts the positive electrode sheet and passes through the gap between the first and second shaping rollers. The composite electrode sheet advances toward the composite electrode sheet winding mechanism 12 under the action of the composite electrode sheet winding mechanism 12, and is received and wound by the composite electrode sheet winding mechanism 12, resulting in a composite electrode sheet with solid electrolyte membrane on both sides of the positive electrode sheet. After the substrate leaves the gap between the first and second shaping rollers 31 and 32, the substrate rotates a certain angle with the first or second shaping roller 31 and 32, and then is conveyed to the third guide roller 53 under the action of the substrate winding mechanism 22. The substrate is received and wound by the substrate winding mechanism 22 located downstream of the third guide roller 53.

[0276] The thickness of the middle area of ​​the composite pole piece was detected to be 160μm, and the thickness of the edge area was 160μm. There were no cracks on the surface of the composite pole piece when observed with the naked eye, which met the use standards of the composite pole piece; the appearance of the glue layer remained good.

[0277] In a comparative example, a roller press as shown in Figure 6 was used to composite the positive electrode sheet with two layers of solid electrolyte membranes, allowing the solid electrolyte membranes to be simultaneously composited onto the positive active material layers on both sides of the positive electrode sheet. The roller press shown in Figure 6 differs from the roller press shown in Figure 5 in that there is no glue layer on the outside of the sizing rollers. The methods for preparing the positive electrode sheet, solid electrolyte membrane, and composite positive electrode sheet are all consistent with those in the previous embodiment.

[0278] There is interlayer separation at the edge of the composite pole piece, and there are fine cracks at the edge.

[0279] In one aspect, the present application provides a composite electrode sheet preparation apparatus, as shown in Figures 7-13. The apparatus includes a shaping roller assembly, an electrode sheet unwinding mechanism 11, a solid electrolyte membrane unwinding mechanism 21, and a heating roller. The shaping roller assembly includes a first shaping roller 31 and a second shaping roller 32 symmetrically arranged on either side of the electrode sheet; the connecting line between the axes of the first shaping roller 31 and the second shaping roller 32 is perpendicular to the direction of conveyance of the electrode sheet.

[0280] The electrode sheet unwinding mechanism 11 is located upstream of the shaping roller assembly and is used to unwind the electrode sheet and then transport the electrode sheet so that the electrode sheet passes through the gap between the first shaping roller 31 and the second shaping roller 32 .

[0281] It can be understood that the electrode plate of the present application is a positive electrode plate or a negative electrode plate.

[0282] The solid electrolyte membrane unwinding mechanism 21 is located upstream of the sizing roller assembly, more specifically, between the electrode sheet unwinding mechanism 11 and the sizing roller assembly. The solid electrolyte membrane unwinding mechanism 21 is used to unwind the solid electrolyte membrane and then transport the solid electrolyte membrane so that the solid electrolyte membrane passes through the gap between the first sizing roller 31 and the second sizing roller 32. More specifically, the solid electrolyte membrane unwinding mechanism 21 allows the solid electrolyte membrane to pass through the gap between the electrode sheet and the sizing roller assembly.

[0283] In some embodiments, there are two solid electrolyte membrane unwinding mechanisms 21, one on each side of the electrode sheet unwinding mechanism 11, and the solid electrolyte membrane is then transported so that the two layers of solid electrolyte membrane pass through the gap between the first shaping roller 31 and the second shaping roller 32, respectively, and the electrode sheet is located between the two layers of solid electrolyte membrane. Optionally, the two solid electrolyte membrane unwinding mechanisms 21 are symmetrically arranged on both sides of the electrode sheet unwinding mechanism 11. However, this is not limited to this. In some embodiments, there is one solid electrolyte membrane unwinding mechanism, which is arranged on one side of the electrode sheet unwinding mechanism. The solid electrolyte membrane unwinding mechanism unwinds and then transports the solid electrolyte membrane so that the solid electrolyte membrane passes through the gap between the first shaping roller and the second shaping roller, so that the solid electrolyte membrane is composited on one side of the electrode sheet.

[0284] The heating roller is located between the electrode sheet unwinding mechanism 11 and the shaping roller assembly, and is used to preheat the electrode sheet and / or the solid electrolyte membrane.

[0285] In some embodiments, the composite electrode preparation device further includes a guide roller, which is located between the electrode sheet unwinding mechanism 11 and the shaping roller assembly and is used to adjust the preheating time of the electrode sheet and / or the solid electrolyte membrane.

[0286] In some embodiments, there is no particular restriction on the number of guide rollers and heating rollers in the composite electrode preparation device, and the specific number can be increased or decreased according to actual conditions.

[0287] In some embodiments, the number of the heating roller may be one, ie, the first heating roller 71 .

[0288] In some embodiments, there are multiple heating rollers, and the temperature of the heating rollers gradually increases along the direction of the electrode sheet. Specifically, the heating rollers along the direction of the electrode sheet can be, in order, a first heating roller 71, a second heating roller 72, and a third heating roller 73. The number of the first heating roller 71, the second heating roller 72, and the third heating roller 73 can also be one, two, or more, without particular limitation.

[0289] In some embodiments, the heating roller is used to preheat the electrode sheet alone, without preheating the solid electrolyte membrane.

[0290] In some embodiments, the heating roller is used to preheat the solid electrolyte membrane alone, without preheating the electrode plates.

[0291] In some embodiments, the heating roller is used to preheat the electrode sheet and the solid electrolyte membrane. It is understood that the electrode sheet and the solid electrolyte membrane can be preheated using the same heating roller or different heating rollers.

[0292] In some embodiments, a guide roller is provided between the electrode sheet unwinding mechanism 11 and the heating roller to provide guidance for the electrode sheet and / or In some embodiments, a guide roller is provided between the solid electrolyte membrane unwinding mechanism 21 and the heating roller to provide guidance for the solid electrolyte membrane.

[0293] By adjusting the relative position between the guide roller and the heating roller, the preheating time of the electrode sheet and / or the solid electrolyte membrane can be adjusted.

[0294] The elastic member is located between the first shaping roller 31 and the second shaping roller 32 .

[0295] During the production of electrode sheets, the edges of the electrode sheets are usually thinned to ensure smooth rolling of the subsequent rolling process. However, the presence of the thinned areas of the electrode sheets affects the fit between the solid electrolyte membrane and the electrode sheets.

[0296] In some embodiments, the composite electrode preparation device of the present application utilizes the buffer provided by the elastic member during rolling, so that the solid electrolyte membrane can better cover the electrode electrode; at the same time, during the rolling process of the shaping roller assembly, the electrode electrode is thick in the middle, resulting in the force in the middle area of ​​the electrode electrode being greater than the edge area, and the lateral thickness of the electrode electrode tends to be consistent after rolling.

[0297] In some embodiments, the elastic member is made of a flexible material, which undergoes elastic deformation under pressure. The tiny elastic deformation makes the thickness of the middle area and the thinned area of ​​the electrode plate tend to be consistent under pressure, so that the electrode plate and the solid electrolyte membrane can fit better.

[0298] In some embodiments, the flexible material is a polymer. The present application does not impose any particular restrictions on the material of the polymer. For example, the polymer material can be a plastic such as polytetrafluoroethylene, polyethylene terephthalate, polypropylene, or polyacrylonitrile; a rubber such as Hypalon rubber, silicone rubber, or fluororubber; or an elastic material such as silicone rubber that can undergo a certain degree of deformation.

[0299] The present application does not particularly limit the thickness of the elastic member. Any necessary adjustment to the thickness of the elastic member without violating the inventive concept of the present application can be understood as being within the scope of protection of the present application.

[0300] In some embodiments, the elastic member is arranged corresponding to the solid electrolyte membrane. For example, when one side of the electrode plate is composited with a solid electrolyte membrane, the elastic member is arranged in the gap between the shaping roller close to the side of the solid electrolyte membrane and the solid electrolyte membrane. When both sides of the electrode plate are composited with a solid electrolyte membrane, the elastic member is arranged in the gap between the two shaping rollers and the solid electrolyte membrane on the corresponding side.

[0301] In some embodiments, the elastic member is a rubber layer 81 that surrounds and covers the outer side of the first shaping roller 31 and / or the second shaping roller 32 .

[0302] In some embodiments, the elastic member is a protective film that is transported through the gap between the sizing roller assembly and the solid electrolyte membrane.

[0303] Adaptively, the composite electrode sheet preparation apparatus of the present application further includes a protective film unwinding mechanism 41 for unwinding the protective film. The protective film unwinding mechanism 41 is located upstream of the sizing roller assembly and disposed between the solid electrolyte membrane unwinding mechanism 21 and the sizing roller assembly. During the roll-pressing process of the electrode sheet and the solid electrolyte membrane, the protective film is located in the gap between the first sizing roller 31 and the second sizing roller 32, and between the sizing roller assembly and the solid electrolyte membrane.

[0304] This application does not have any particular requirements for the structure of the protective film. Any known film capable of undergoing a certain degree of elastic deformation under a certain pressure can be used in this application, provided that it does not violate the inventive concept of this application. This example is provided merely as an illustrative example and does not limit the scope of protection. The protective film can be selected from polymer films or non-woven fabrics, including but not limited to PP-based non-woven fabrics, PE-based non-woven fabrics, PET-based non-woven fabrics, PAN-based non-woven fabrics, PTFE-based non-woven fabrics, and Celgard non-woven fabrics. The polymer film can be selected from PVDF film, PE film, PP film, PE / PP film, PE / PP / PE film, PP / PE / PP film, PTFE film, silicone oil release film, fluorine release film, PET film, and non-silicone release film. It is understood that the protective film can also be a multilayer structure composed of two or more layers of polymer films and / or non-woven fabrics.

[0305] This application does not specifically limit the thickness of the protective film. Without violating the inventive concept of this application, any conventional adjustment of the thickness of the protective film for adjusting the rolling effect should be considered within the scope of protection of this application. It can be understood that when the protective film is a multi-layer structure, the thickness of the protective film should be the sum of the thicknesses of the multi-layer structure.

[0306] In some embodiments, the composite electrode sheet preparation apparatus further includes a composite electrode sheet winding mechanism 12. The composite electrode sheet winding mechanism 12 is located downstream of the shaping roller assembly and is used to provide a pulling force to the electrode sheet along the direction of movement of the electrode sheet and to receive the composite electrode sheet obtained after being rolled by the shaping roller assembly to complete the winding action.

[0307] In some embodiments, the composite electrode preparation device further includes a substrate winding mechanism 22 .

[0308] When a substrate is placed on the solid electrolyte membrane, it covers the side of the solid electrolyte membrane away from the electrode sheet. After the electrode sheet and solid electrolyte membrane are rolled together by the sizing roller assembly to form a composite electrode sheet, the substrate needs to be separated. A substrate rewinding mechanism 22 is provided downstream of the sizing roller assembly to achieve separation of the substrate from the composite electrode sheet. During the separation process, the substrate rewinding mechanism 22 applies tension to the substrate covering the solid electrolyte membrane, separating it from the composite electrode sheet and rewinding the substrate as necessary.

[0309] The number of the substrate winding mechanisms 22 corresponds to the number of the solid electrolyte membrane unwinding mechanisms 21 , and the substrate winding mechanisms 22 and the solid electrolyte membrane unwinding mechanisms 21 are located on the same side of the electrode sheet unwinding mechanism 11 .

[0310] In some embodiments, a guide roller may be provided between the shaping roller assembly and the substrate winding mechanism 22 , and the guide roller is used to provide guidance for the substrate separated from the composite electrode sheet.

[0311] In some embodiments, the composite electrode sheet preparation apparatus further includes a protective film winding mechanism 42. The protective film winding mechanism 42 is located downstream of the shaping roller assembly and is disposed between the shaping roller assembly and the composite electrode sheet winding mechanism 12. The protective film winding mechanism 42 is used to provide tension to the protective film and to wind up the protective film.

[0312] In some embodiments, a guide roller is provided between the protective film unwinding mechanism 41 and the shaping roller assembly to provide guidance for the solid electrolyte membrane and / or protective film. A guide roller may also be provided between the shaping roller assembly and the protective film rewinding mechanism 42 to provide guidance for the recovery of the protective film.

[0313] In some embodiments, the heating roller is used to preheat the electrode sheet, the solid electrolyte membrane, and the protective membrane. It is understood that the electrode sheet, the solid electrolyte membrane, and the protective membrane can be preheated using the same heating roller or different heating rollers.

[0314] In some embodiments, the heating roller is used to preheat the electrode plates and the solid electrolyte membrane, but not the protective membrane.

[0315] In some embodiments, the preparation device of the composite electrode further includes an unwinding correction component, an electrode anti-static component, etc., which are sequentially arranged along the unwinding route. The unwinding correction component can correct the unwinding and running routes of the electrode electrode and the solid electrolyte membrane, etc., so that the starting material line remains at the same level. The unwinding and winding mechanism of the main material adopts a single-station correction, and the unwinding and winding of the remaining materials adopts a cantilever type, all with correction. The anti-static component performs anti-static treatment on both sides of the electrode electrode, which can reduce the friction between the electrode and the conveying roller. It can be understood that, without violating the inventive concept of the present application, in the entire process from winding, rolling, and unwinding, known functional components or structures can be used in the present application.

[0316] In some embodiments, the width of the sizing roller assembly is 500-800 mm, including but not limited to 500 mm, 550 mm, 600 mm, 650 mm, 700 mm, 750 mm, and 800 mm, preferably 550-650 mm.

[0317] In some embodiments, the roller diameter of the sizing roller assembly is 300-500 mm, including but not limited to 300 mm, 350 mm, 400 mm, 450 mm, and 500 mm, preferably 350-450 mm.

[0318] In some embodiments, the tonnage of the sizing roller assembly is 10-15 tons, including but not limited to 11 tons, 12 tons, 13 tons, 14 tons, and 15 tons, preferably 11-13 tons.

[0319] In some embodiments, the mechanical speed of the sizing roller assembly is 10-60 m / min, including but not limited to 10 m / min, 20 m / min, 30 m / min, 40 m / min, 45 m / min, 50 m / min, and 60 m / min.

[0320] It is understood that higher speeds for the composite electrode sheet production apparatus result in higher production efficiency. However, excessively high speeds can easily lead to problems such as electrode sheet and solid electrolyte membrane breakage. This application does not specifically require the residence time of the electrode sheet and solid electrolyte membrane within the gap between the sizing rollers. Adjustments to the residence time that do not require inventive effort, provided they do not violate the inventive concept of this application, should be understood to fall within the scope of protection of this application.

[0321] In some embodiments, the linear speeds of the first shaping roller 31 and the second shaping roller 32 are kept consistent, and the linear speed of the electrode sheet unwinding mechanism 11 and the linear speed of the composite sheet winding mechanism 12 are also kept consistent, thereby improving the consistency of the entire composite sheet rolling preparation process and improving the consistency of the composite sheet.

[0322] In some embodiments, a heating unit is provided inside the sizing roller assembly, and the temperature range of the sizing roller is 100-300°C, including but not limited to 100°C, 150°C, 200°C, 250°C, and 300°C, preferably 150-200°C.

[0323] In some embodiments, the elastic member in the composite electrode preparation device is a glue layer 81, and the solid electrolyte membrane is not covered with a substrate. Referring to Figures 7-9, the same or different heating rollers are used to preheat the electrode electrode and / or solid electrolyte membrane. Specifically, in Figure 7, the heating roller is only used to preheat the electrode electrode; in Figure 8, the same heating roller is used to preheat the electrode electrode and solid electrolyte membrane simultaneously; in Figure 9, different heating rollers are used to preheat the electrode electrode and solid electrolyte membrane separately. Exemplary:

[0324] FIG7 is a schematic diagram of the structure of a preparation device in which a heating roller is used to preheat an electrode sheet separately. The specific operation process is as follows: the electrode sheet is unwound by the electrode sheet unwinding mechanism 11 and conveyed to the composite electrode sheet winding mechanism 12. The electrode sheet passes through the gaps between the first guide roller 51, the first heating roller 71, the second heating roller 72, the ninth guide roller 59, the first shaping roller 31 and the second shaping roller 32 in sequence. The solid electrolyte membrane is conveyed by the solid electrolyte membrane unwinding mechanism 21 located on the upper and lower sides of the electrode sheet unwinding mechanism 11. The solid electrolyte membrane passes through the gap between the second guide roller 52, the third guide roller 53, the shaping roller assembly and the electrode sheet in sequence. The solid electrolyte is located between the shaping roller assembly and the electrode sheet. The electrode sheet and the solid electrolyte membrane are rolled and composited by the first shaping roller 31 covered with a glue layer 81 on the outside and the second shaping roller 32 covered with a glue layer 81 on the outside to obtain a composite electrode sheet. The composite electrode sheet reaches the composite electrode sheet winding mechanism 12 and is received by the composite electrode sheet winding mechanism 12.

[0325] Figure 8 is a schematic structural diagram of a preparation device that uses the same heating roller to preheat the electrode sheet and the solid electrolyte membrane. The specific usage process is as follows: the electrode sheet is unwound by the electrode sheet unwinding mechanism 11 and conveyed to the composite electrode sheet rewinding mechanism 12; the solid electrolyte membrane is respectively conveyed by the solid electrolyte membrane unwinding mechanisms 21 located on the upper and lower sides of the electrode sheet unwinding mechanism 11. The electrode sheet and the solid electrolyte membrane are first bonded on the first guide roller 51, and then pass through the gap between the first heating roller 71, the second heating roller 72, the ninth guide roller 59, the first shaping roller 31 and the second shaping roller 32 in sequence. The solid electrolyte is located between the shaping roller assembly and the electrode sheet. The bonded electrode sheet and the solid electrolyte membrane are rolled and composited by the first shaping roller 31 covered with a glue layer 81 on the outside and the second shaping roller 32 covered with a glue layer 81 on the outside to obtain a composite electrode sheet; the composite electrode sheet reaches the composite electrode sheet rewinding mechanism 12 and is received by the composite electrode sheet rewinding mechanism 12.

[0326] FIG9 is a schematic diagram of the structure of a preparation device for preheating an electrode sheet and a solid electrolyte membrane using different heating rollers. The specific use process is as follows: the electrode sheet is unwound by the electrode sheet unwinding mechanism 11 and is conveyed to the composite sheet rewinding mechanism 12. The electrode sheet passes through the gaps between the first guide roller 51, the first heating roller 71, the sixth guide roller 56, the ninth guide roller 59, the first shaping roller 31 and the second shaping roller 32 in sequence; the electrode sheet is unwound by the solid electrolyte membrane unwinding mechanism 21 located on the upper and lower sides of the electrode sheet unwinding mechanism 11. The solid electrolyte membrane is transported separately, and the solid electrolyte membrane passes through the second guide roller 52, the second heating roller 72, the ninth guide roller 59, the gap between the shaping roller assembly and the electrode plate in turn. The solid electrolyte is located between the shaping roller assembly and the electrode plate. The electrode plate and the solid electrolyte membrane are rolled and compounded by the first shaping roller 31 covered with a glue layer 81 on the outside and the second shaping roller 32 covered with a glue layer 81 on the outside to obtain a composite plate; the composite plate reaches the composite plate winding mechanism 12 in turn, and the composite plate is received by the composite plate winding mechanism 12.

[0327] In the examples shown in Figures 7-9 above, a layer of adhesive 81 covers the outside of the first and second sizing rollers. As the sizing roller assembly rotates, the adhesive layer 81 rotates with it. Furthermore, as the sizing roller assembly rolls the solid electrolyte membrane and / or electrode sheet, the adhesive layer 81 provides a cushioning effect on the solid electrolyte membrane and / or electrode sheet, allowing the solid electrolyte membrane to better cover one or both sides of the electrode sheet and improving the consistency of the lateral thickness of the electrode sheet after rolling.

[0328] In some embodiments, the elastic member in the composite electrode sheet preparation apparatus is a protective film. The protective film can be unwound by two protective film unwinding mechanisms 41 located on the side of the solid electrolyte membrane unwinding mechanism 21 away from the electrode electrode sheet. The two protective film unwinding mechanisms 41 respectively convey the protective film to the shaping roller assembly, so that the two layers of protective film 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 protective film, solid electrolyte membrane, electrode electrode sheet, solid electrolyte membrane, and protective film, which are distributed in sequence, are bonded to each other. Under the rolling action of the shaping roller assembly, the solid electrolyte membrane is composited on both sides of the electrode electrode sheet, thereby forming a composite electrode sheet.

[0329] During rolling, the shaping roller assembly applies tensioning force to the electrode sheet and the solid electrolyte membrane, and the two layers of protective film are located between the shaping roller assembly and the solid electrolyte membrane, which play a buffering role, so that the force applied to each site of the electrode sheet and the solid electrolyte membrane is relatively uniform. Finally, the solid electrolyte membrane in the composite sheet almost completely covers the electrode sheet, the bonding between the electrode sheet and the solid electrolyte membrane is better, the consistency of the lateral thickness of the composite sheet is improved, and the compaction density is also improved.

[0330] In some embodiments, the elastic member in the composite electrode preparation device is a protective film, and the solid electrolyte membrane is not covered with a substrate. Referring to Figures 10-11, the same or different heating rollers are used to preheat the electrode electrode, solid electrolyte membrane, and protective membrane. Specifically, in Figure 10, the same heating roller is used to preheat the electrode electrode, solid electrolyte membrane, and protective membrane; in Figure 11, different heating rollers are used to preheat the electrode electrode, solid electrolyte membrane, and protective membrane. Exemplary:

[0331] Figure 10 is a structural schematic diagram of a preparation device that uses the same heating roller to preheat the electrode sheet, solid electrolyte membrane, and protective membrane. The specific usage process is as follows: the electrode sheet is unwound by the electrode sheet unwinding mechanism 11 and is conveyed to the composite sheet rewinding mechanism 12, and the electrode sheet directly reaches the first guide roller 51; the solid electrolyte membrane is respectively conveyed by the solid electrolyte membrane unwinding mechanism 21 located on the upper and lower sides of the electrode sheet unwinding mechanism 11; the protective membrane is respectively conveyed by the protective membrane unwinding mechanism 41 located on the upper and lower sides of the electrode sheet unwinding mechanism 11, and the solid electrolyte membrane and protective membrane located in the upper area of ​​the electrode sheet unwinding mechanism 11 directly reach the first guide roller 51, and the solid electrolyte membrane and protective membrane located in the lower area of ​​the electrode sheet first pass through the seventh guide roller 57 and then reach the first guide roller 57. Toward roller 51, the electrode pole piece, two layers of solid electrolyte membrane and two layers of protective film are bonded on the first guide roller 51, and then pass through the gap between the first heating roller 71, the second heating roller 72, the ninth guide roller 59, the first shaping roller 31 and the second shaping roller 32 in sequence. The solid electrolyte is located between the shaping roller assembly and the electrode pole piece, and the protective film is located between the shaping roller assembly and the solid electrolyte membrane. The electrode pole piece, the solid electrolyte membrane and the protective film bonded together are rolled and compounded by the first shaping roller 31 and the second shaping roller 32 to obtain a composite pole piece covered with a protective film; then the two protective film winding mechanisms 42 complete the winding action of the two layers of protective film, so that the protective film is separated from the composite pole piece; the composite pole piece reaches the composite pole piece winding mechanism 12, and the composite pole piece is received by the composite pole piece winding mechanism 12.

[0332] Figure 11 is a schematic diagram of the structure of a preparation device that uses different heating rollers to preheat the electrode sheet, solid electrolyte membrane, and protective membrane. The specific use process is as follows: the electrode sheet is unwound by the electrode sheet unwinding mechanism 11 and is conveyed to the composite sheet rewinding mechanism 12. The electrode sheet passes through the gap between the first guide roller 51, the first heating roller 71, the sixth guide roller 56, the ninth guide roller 59, the first shaping roller 31, and the second shaping roller 32 in sequence; the solid electrolyte membrane is conveyed separately by the solid electrolyte membrane unwinding mechanism 21 located on the upper and lower sides of the electrode sheet unwinding mechanism 11. The solid electrolyte membrane passes through the second heating roller 72, the ninth guide roller 59, the shaping roller assembly and the gap between the electrode sheet in sequence. The solid electrolyte is located between the shaping roller assembly and the electrode sheet; The protective film unwinding mechanisms 41 located on the upper and lower sides of the electrode sheet unwinding mechanism 11 respectively transport the protective film, which passes through the third heating roller 73, the ninth guide roller 59, the shaping roller assembly and the gap between the electrode sheet in turn. The protective film is located between the shaping roller assembly and the solid electrolyte membrane. The electrode sheet, the solid electrolyte membrane and the protective film bonded together are rolled and composited by the first shaping roller 31 and the second shaping roller 32 to obtain a composite sheet covered with a protective film; then the protective film passes from the shaping roller assembly through the eighth guide roller 58 to the protective film winding mechanism 42, and the two protective film winding mechanisms 42 complete the winding action of the two layers of protective film, so that the protective film is separated from the composite sheet; the composite sheet arrives at the composite sheet winding mechanism 12, and is received by the composite sheet winding mechanism 12.

[0333] In some embodiments, the solid electrolyte membrane is covered with a substrate to provide support for the solid electrolyte membrane. The solid electrolyte membrane unwinding mechanism 21 conveys the solid electrolyte membrane so that the substrate is positioned on the side of the solid electrolyte membrane away from the electrode sheet. After the solid electrolyte membrane and the electrode sheet are fully composited, the substrate is separated from the composite electrode sheet.

[0334] When the solid electrolyte membrane is covered with a substrate, the preparation apparatus further includes a substrate winding mechanism 22 located above and below the region between the sizing roller assembly and the composite electrode sheet winding mechanism 12. The bonding strength between the substrate and the solid electrolyte membrane is weaker than the bonding strength between the solid electrolyte membrane and the electrode sheet. After roller-compression lamination, at least a portion of the solid electrolyte is transferred to the electrode, separating from the substrate.

[0335] Based on Figure 11, the solid electrolyte membrane is covered with a substrate. Referring to Figures 12-13, in Figure 12, the protective film and substrate are separated from the composite electrode simultaneously; in Figure 13, the protective film and substrate are separated from the composite electrode sequentially; that is, the paths that the substrate takes from the sizing roller assembly to the substrate winding mechanism 22 are different. For example:

[0336] Referring to Figures 12-13, different heating rollers are used to preheat the electrode plates, solid electrolyte membranes, and protective films. In Figure 12, the substrate and protective film are separated from the composite plate simultaneously, and pass through the same guide roller to reach the substrate winding mechanism 22; in Figure 13, the substrate and protective film are separated from the composite plate successively, and pass through different guide rollers to reach the substrate winding mechanism 22. The specific usage process is as follows: the electrode sheet is unwound by the electrode sheet unwinding mechanism 11 and conveyed to the composite sheet winding mechanism 12, and the electrode sheet passes through the gap between the first guide roller 51, the first heating roller 71, the sixth guide roller 56, the ninth guide roller 59, the first shaping roller 31 and the second shaping roller 32 in sequence; the solid electrolyte membrane is conveyed separately by the solid electrolyte membrane unwinding mechanism 21 located on the upper and lower sides of the electrode sheet unwinding mechanism 11, and the solid electrolyte membrane passes through the second heating roller 72, the ninth guide roller 59, the shaping roller assembly and the gap between the electrode sheet in sequence, and the solid electrolyte is located between the shaping roller assembly and the electrode sheet; the protective film is conveyed separately by the protective film unwinding mechanism 41 located on the upper and lower sides of the electrode sheet unwinding mechanism 11, and the protective film passes through the third heating roller 73, the ninth guide roller 59, the shaping roller assembly and the gap between the electrode sheet in sequence, and the protective film is located between the shaping roller assembly and the solid electrolyte In the middle of the plasma membrane, the electrode plate, solid electrolyte membrane and protective film bonded together are rolled and composited by the first shaping roller 31 and the second shaping roller 32 to obtain a composite plate covered with a protective film and a substrate; in Figure 12, the protective film is passed from the shaping roller assembly and the substrate through the eighth guide roller 58 and then reaches the protective film winding mechanism 42 and the substrate winding mechanism 22 respectively, and the protective film is wound by the protective film winding mechanism 42 to separate the protective film from the composite plate, and the substrate is wound by the substrate winding mechanism 22 to separate the substrate from the surface of the solid electrolyte membrane; in Figure 13, the protective film is passed from the shaping roller assembly through the eighth guide roller 58 and then reaches the protective film winding mechanism 42, and the substrate is passed from the shaping roller assembly through the tenth guide roller 60 and the eleventh guide roller 61 and then reaches the substrate winding mechanism 22; it reaches the composite plate winding mechanism 12 through the composite plate, and receives the composite plate through the composite plate winding mechanism 12.

[0337] In the above example, optionally, the number of the first heating roller 71 or the second heating roller 72 can be 1, 2 or more. There is no particular limitation on the number of the first heating roller 71 and the second heating roller 72, and they can be selected and replaced according to actual needs.

[0338] In the above example, the ninth guide roller 59 can be replaced by one, two, or more than one guide roller. There is no specific limit on the number of ninth guide rollers 59 and they can be replaced based on actual needs. They can also be replaced by an unwinding guide assembly. Similarly, there is no specific limit on the number of other guide rollers, such as the first guide roller 51 and the second guide roller 52, and they can be selected based on actual needs.

[0339] In the above example, optionally, the number of the solid electrolyte membrane unwinding mechanism 21 may also be one.

[0340] The distribution of multiple guide rollers in the composite electrode preparation device in this application is not limited to the several cases exemplified above. This application does not specifically limit the distribution of the guide rollers. Without violating the inventive concept of this application, any distribution method that can achieve the adjustment of the preheating time should be included in the protection scope of this application.

[0341] Another aspect of the present application provides a composite electrode produced using the aforementioned production device.

[0342] In this application, multiple guide rollers guide the electrode sheets and / or solid electrolyte membranes and / or protective membranes, controlling the contact between the electrode sheets and / or solid electrolyte membranes and the heating rollers. This allows for different travel distances between the electrode sheets and / or solid electrolyte membranes on the heating rollers, thereby adjusting the preheating time. The preheating temperature is controlled by controlling the temperature and number of heating rollers that each membrane passes through. By rationally arranging the number and position of guide rollers, the preheating processes of different membranes are independent of each other, resulting in strong operability, high controllability, and easy maintenance. This ensures uniform preheating, improves the bonding strength of the composite positive electrode sheets, and prevents powder shedding during the battery's charge and discharge cycles.

[0343] Another aspect of the present application provides a method for preparing a composite electrode sheet to improve the composite effect of a dry composite electrode sheet and a solid electrolyte membrane. Referring to Figures 15-16, a composite electrode sheet preparation device for preparing the composite electrode sheet of the present application includes an electrode sheet unwinding mechanism, a first solid electrolyte membrane unwinding mechanism, a second solid electrolyte membrane unwinding mechanism, a first heater, a second heater, a first shaping roller assembly, a second shaping roller assembly, and a composite electrode sheet winding mechanism. The first shaping roller assembly is located upstream of the second shaping roller assembly, and at least one of the first shaping roller assembly and the second shaping roller assembly is configured as an elastic rolling assembly; the elastic rolling assembly includes a rigid roller and an elastic roller having a lower hardness than the rigid roller, and the connecting line between the rigid roller and the elastic roller axis is perpendicular to the conveying direction of the electrode sheet, that is, the conveying direction of the electrode sheet is perpendicular to the plane where the axis of the rigid roller and the axis of the elastic roller are located, but this is not limited to this. The conveying direction of the electrode sheet can be adaptively adjusted according to actual production needs.

[0344] In some embodiments, the first shaping roller assembly and the second shaping roller assembly each include two rollers symmetrically arranged on both sides of the electrode sheet, and the connecting line between the axes of the two rollers is perpendicular to the conveying direction of the electrode sheet, that is, the plane where the axes of the two rollers of each set of shaping roller assemblies are located is perpendicular to the conveying direction of the electrode sheet.

[0345] Optionally, the first shaping roller assembly includes a rigid roller and an elastic roller; and the second shaping roller assembly includes two rigid rollers.

[0346] Alternatively, the first shaping roller assembly and the second shaping roller assembly each include a rigid roller and an elastic roller.

[0347] Alternatively, the first shaping roller assembly includes two rigid rollers; and the second shaping roller assembly includes a rigid roller and an elastic roller.

[0348] Preferably, the first and second shaping roller assemblies each include a rigid roller and an elastic roller. The solid electrolyte membrane and electrode sheet are unwound and conveyed separately through the gap between the rigid roller and the elastic roller of the first shaping roller assembly and the gap between the rigid roller and the elastic roller of the second shaping roller assembly. Exemplarily, as shown in FIG15 , the first shaping roller assembly includes a first rigid roller 36 and a first elastic roller 35 disposed opposite the first rigid roller 36 , with the first elastic roller 35 located on the side of the first solid electrolyte membrane away from the electrode sheet. The second shaping roller assembly includes a second rigid roller 33 and a second elastic roller 34 disposed opposite the second rigid roller 33 , with the second elastic roller 34 located on the side of the second solid electrolyte membrane away from the electrode sheet.

[0349] The first solid electrolyte membrane and electrode sheet are preheated before entering the first shaping roller assembly. After preheating, the first solid electrolyte membrane and electrode sheet soften compared to before preheating, improving their ductility. As a result, when the first shaping roller assembly rolls the first solid electrolyte membrane and electrode sheet, the first solid electrolyte membrane and electrode sheet interlock more tightly, increasing the bond strength between the two and further enhancing their composite effect. Similarly, the second solid electrolyte membrane and composite membrane are heated before entering the second shaping roller assembly, which also improves the composite effect between the second solid electrolyte membrane and the composite membrane, resulting in a composite electrode sheet with better composite effect.

[0350] Preferably, when a substrate is provided on the solid electrolyte membrane, the substrate covers a side of the solid electrolyte membrane away from the electrode plate.

[0351] As an embodiment, the first substrate is separated after the electrode sheet and the first solid electrolyte membrane are rolled by a first shaping roller assembly to obtain a composite membrane sheet.

[0352] Preferably, the first substrate is separated from the composite membrane by arranging a first substrate winding mechanism between the first shaping roller assembly and the second shaping roller assembly, so as to improve the heating effect of the second solid electrolyte membrane in the subsequent second heater, and also improve the composite effect between the composite membrane and the second solid electrolyte membrane; the first substrate winding mechanism and the first solid electrolyte membrane unwinding mechanism are located on the same side of the electrode sheet unwinding mechanism, and are used to receive the substrate covering the side of the first solid electrolyte away from the electrode sheet.

[0353] After the first solid electrolyte membrane and the electrode plate are combined, the substrate and the composite membrane are preferably separated by the substrate separation device, so that the composite membrane avoids the influence of the substrate when entering the second heater.

[0354] When the second substrate needs to be separated after the composite membrane and the second solid electrolyte membrane are rolled by the second shaping roller assembly to form a composite electrode sheet, a second substrate rewinding mechanism is provided downstream of the second shaping roller assembly to achieve separation of the second substrate from the composite electrode sheet. The second substrate rewinding mechanism and the first substrate rewinding mechanism are located on either side of the electrode sheet unwinding mechanism. More specifically, the second substrate rewinding mechanism and the first substrate rewinding mechanism are located on either side of the electrode sheet transmission surface, and are used to receive the substrate covering the side of the second solid electrolyte away from the electrode sheet. During the separation process, the first substrate rewinding mechanism and the second substrate rewinding mechanism respectively apply tension to the first and second substrates, separating the first and second substrates from the composite membrane or composite electrode sheet, and completing the substrate rewinding action when necessary.

[0355] Optionally, the first substrate winding mechanism is located between the first shaping roller assembly and the second shaping roller assembly.

[0356] Alternatively, the first substrate winding mechanism and the second substrate winding mechanism are both located downstream of the second shaping roller assembly, and are symmetrically arranged on both sides of the composite electrode winding mechanism.

[0357] In some embodiments, the rigid rollers in the first and second shaping roller assemblies may be internally provided with a heating device to improve the lamination effect. The elastic roller may optionally be internally provided with a heating device.

[0358] The electrode sheet unwinding mechanism is located upstream of the first shaping roller assembly and the first heater, and is used to unwind the electrode sheet, then transport the electrode sheet so that the electrode sheet reaches the first heater for heating, and then continue to transport the heated electrode sheet to the gap in the middle of the first shaping roller assembly.

[0359] The first solid electrolyte membrane unwinding mechanism is located upstream of the first sizing roller assembly and the first heater, and more specifically, between the electrode sheet unwinding mechanism and the first heater. The first solid electrolyte membrane unwinding mechanism is used to unwind the first solid electrolyte membrane, then transport the first solid electrolyte membrane to the first heater for heating, and then transport the heated first solid electrolyte membrane to the gap between the first sizing roller assembly.

[0360] The second solid electrolyte membrane unwinding mechanism is located downstream of the first sizing roller assembly, more specifically, between the first sizing roller assembly and the second heater. The second solid electrolyte membrane unwinding mechanism is used to unwind the second solid electrolyte membrane, then transport the second solid electrolyte membrane to the second heater for heating, and then continue to transport the heated second solid electrolyte membrane to the gap between the second sizing roller assembly.

[0361] The first heater is located between the electrode sheet unwinding mechanism and the first shaping roller assembly, more specifically between the first solid electrolyte membrane unwinding mechanism and the first shaping roller assembly, and is used to heat the electrode sheet and / or the first solid electrolyte membrane.

[0362] The internal channels of the first heater and the second heater are parallel to the running direction of the electrode plates. That is, during the entire process from entering the first heater / second heater to leaving the first heater / second heater, the movement direction of the electrode plates and / or the first solid electrolyte membrane and / or the second solid electrolyte membrane remains consistent. This heating method reduces the relative displacement of the electrode plates, the first solid electrolyte membrane and the second solid electrolyte membrane during movement, and to a certain extent ensures the composite effect of the electrode plates, the first solid electrolyte membrane and the second solid electrolyte membrane.

[0363] It is understood that the present application preheats the electrode plate and the solid electrolyte membrane by providing a first heater and a second heater, and the present application does not particularly limit the type and structure of the first heater and the second heater. As an illustrative example, the path of the first heater heating the electrode plate and the first solid electrolyte membrane is the same as the direction of operation of the electrode plate, so as to reduce unnecessary relative displacement of the electrode plate and the first solid electrolyte membrane during the heating process.

[0364] In some embodiments, the first heater and the second heater employ blast heating, radiant heating, and contact heating. One or more rollers may be disposed within the first heater and the second heater to provide support for the electrode sheet and / or the first solid electrolyte membrane, allowing the electrode sheet and / or the first solid electrolyte membrane to pass more smoothly through the first heater and the second heater, thereby providing more uniform heating to both.

[0365] Preferably, heat-insulating materials are provided in the passages of the first heater and the second heater to prevent heat loss and further improve the heating effect.

[0366] In some embodiments, the temperatures of the first heater and the second heater can be adjusted as needed. Preferably, the temperatures of the first heater and the second heater are higher than the softening temperatures of the electrode and the solid electrolyte membrane.

[0367] It can be understood that the softening temperature of the above-mentioned electrode plates and solid electrolyte membranes refers to the temperature above which the surface hardness of the electrode plates or solid electrolytes changes, and the electrodes and solid electrolyte membranes form a complete composite structure under the action of rolling pressure.

[0368] The second heater is located between the first and second sizing roller assemblies and is used to heat the second solid electrolyte membrane.

[0369] In some embodiments, one or more rollers may be disposed inside the first heater and the second heater to provide support for the composite membrane and / or the second solid electrolyte membrane.

[0370] It is understandable that the longitudinal lengths of the first heater and the second heater along the running direction of the electrode plate are adjustable, so as to meet different heating time requirements.

[0371] In some embodiments, the first heater and the second heater further include a sensor for detecting an internal temperature.

[0372] The composite electrode sheet winding mechanism is located downstream of the second shaping roller assembly, and is used to provide tension to the electrode sheet along the direction of movement of the electrode sheet, and receive the composite electrode sheet obtained after being rolled by the second shaping roller assembly to complete the winding action.

[0373] In some embodiments, the composite electrode preparation device further includes a first substrate winding mechanism and a second substrate winding mechanism.

[0374] In some embodiments, the composite electrode sheet preparation apparatus further includes a cooling roller, located downstream of the second shaping roller assembly, for cooling the composite electrode sheet. This application utilizes a cooling roller to reduce the temperature of the composite electrode sheet, thereby enabling continuous winding of the composite electrode sheet and improving production efficiency. Furthermore, the cooling roller also provides shaping for the composite electrode sheet.

[0375] The number of cooling rollers may be one or more, preferably two.

[0376] Preferably, the cooling roller of the present application adopts a contact cooling roller, which has a better cooling effect.

[0377] In some embodiments, the cooling roller further includes a sensor for detecting the surface temperature of the composite pole piece.

[0378] In some embodiments, the composite pole piece preparation device further includes a guide roller.

[0379] Optionally, a guide roller is located between the first solid electrolyte membrane unwinding mechanism and the first sizing roller assembly to provide guidance for the first solid electrolyte membrane and / or electrode sheet. As shown in Figure 15, the first solid electrolyte membrane originates from the first solid electrolyte membrane unwinding mechanism 25, passes through the first guide roller 51, and then meets and bonds with the electrode sheet originating from the electrode sheet unwinding mechanism 11 at the second guide roller 52. The electrode sheet and the first solid electrolyte membrane pass through the first heater 77 before arriving at the first sizing roller assembly for the first lamination.

[0380] By adjusting the relative position between the guide roller and the first heater, on the one hand, the electrode sheet and the first solid electrolyte membrane can be laminated before being heated together, further ensuring that the temperature of the electrode sheet and the first solid electrolyte membrane is consistent during roll-pressing, thereby avoiding problems such as cracking caused by temperature differences during rolling, which can lead to high defective rates. On the other hand, the direction of movement of the electrode sheet and / or the first solid electrolyte membrane can be kept parallel to the first heater. In this case, the movement of the electrode sheet and / or the first solid electrolyte membrane is smoother and the possibility of relative displacement is reduced.

[0381] Optionally, a guide roller is located between the first shaping roller assembly and the first substrate winding mechanism 26 to guide the first substrate of the first solid electrolyte membrane after it is separated from the composite electrode sheet. As shown in Figure 15, after the electrode sheet and the first solid electrolyte membrane are combined to form a composite membrane sheet at the first shaping roller assembly, the composite membrane continues to move toward the second shaping roller assembly. The first substrate is subjected to a force transmitted by the first substrate winding mechanism 26 via the third guide roller 53 and the fourth guide roller 54, causing the first substrate to separate from the composite membrane sheet at the third guide roller 53 and be wound up by the first substrate winding mechanism 26.

[0382] Optionally, a guide roller is located between the second solid electrolyte membrane unwinding mechanism 23 and the second shaping roller assembly to provide guidance for the second solid electrolyte membrane and / or composite membrane. As shown in Figure 15, the second solid electrolyte membrane departs from the second solid electrolyte membrane unwinding mechanism 23, passes through the sixth guide roller 56, and then meets and bonds with the composite membrane at the seventh guide roller 57. The composite membrane and the second solid electrolyte membrane pass through the fifth guide roller 55, the sixth guide roller 56, and the seventh guide roller 57, and then arrive at the second heater 78 together with the second solid electrolyte membrane. The composite membrane and the second solid electrolyte membrane pass through the second heater 78 and arrive at the second shaping roller assembly for a second lamination.

[0383] Optionally, a guide roller is located between the second shaping roller assembly and the second substrate winding mechanism 24 to provide guidance for the second substrate of the second solid electrolyte membrane separated from the composite electrode sheet. As shown in Figure 15, after the composite membrane sheet and the second solid electrolyte membrane are combined at the second shaping roller assembly to form a composite electrode sheet, the composite electrode sheet continues to move toward the composite electrode sheet winding mechanism 12. The second substrate is separated from the composite electrode sheet at the roller pair formed by the eighth guide roller 58 and the tenth guide roller 60. The second substrate is then moved toward the second substrate winding mechanism 24 by the force transmitted via the ninth guide roller 59, and the winding action is completed by the second substrate winding mechanism 24.

[0384] Optionally, a guide roller is located between the second shaping roller assembly and the composite electrode sheet rewinding mechanism 12 to provide guidance for the composite electrode sheet. As shown in Figure 15, after the composite membrane and the second solid electrolyte membrane are combined at the second shaping roller assembly to form a composite electrode sheet, the composite electrode sheet continues to move toward the composite electrode sheet rewinding mechanism 12. The composite electrode sheet is separated from the second substrate at the roller pair formed by the eighth guide roller 58 and the tenth guide roller 60. After adjusting its direction via the eleventh guide roller 61 and the twelfth guide roller 62, it reaches the first cooling roller 75. The composite electrode sheet rotates around the first cooling roller 75 for a certain angle before reaching the second cooling roller 76. After rotating around the second cooling roller 76 for a certain angle, it moves forward to the composite electrode sheet rewinding mechanism 12 and completes the rewinding of the composite electrode sheet. If necessary, a thirteenth guide roller 63 can be provided between the second cooling roller 76 and the composite electrode sheet rewinding mechanism 12 to adjust the direction of the composite electrode sheet.

[0385] In some embodiments, the composite electrode sheet preparation apparatus further includes a tension control device, an unwinding correction assembly, and an electrode sheet static elimination assembly, sequentially arranged along its unwinding path. The tension control device includes multiple tension control elements positioned upstream of the roller pressing device, each for controlling the unwinding tension of the positive electrode sheet and the solid electrolyte membrane. Optionally, the tension control device includes multiple tension control elements positioned downstream of the roller pressing device, each for controlling the rewinding tension of the composite positive electrode sheet and the substrate. The unwinding correction assembly corrects the unwinding and running paths of the electrode sheet and the solid electrolyte membrane, ensuring that the starting material line remains at the same level. The unwinding and rewinding mechanism for the main material utilizes a single-station correction mechanism, while the unwinding and rewinding mechanism for the remaining materials utilizes a cantilever mechanism, both with correction. The static elimination assembly performs static elimination on both sides of the electrode sheet, reducing friction between the electrode sheet and the conveyor rollers. It is understood that, without departing from the inventive concept of this application, known functional components or structures throughout the entire process from rewinding, rolling, and unwinding can be used in this application.

[0386] In some embodiments, the width of the first and second shaping roller assemblies is 500-800 mm, including but not limited to 500 mm, 550 mm, 600 mm, 650 mm, 700 mm, 750 mm, and 800 mm, preferably 550-650 mm.

[0387] In some embodiments, the roller diameters of the first and second shaping roller assemblies are 300-500 mm, including but not limited to 300 mm, 350 mm, 400 mm, 450 mm, and 500 mm, preferably 350-450 mm.

[0388] In some embodiments, the mechanical speed of the sizing roller assembly is 5-60 m / min, including but not limited to 5 m / min, 10 m / min, 20 m / min, 30 m / min, 40 m / min, 45 m / min, 50 m / min, and 60 m / min.

[0389] It is understood that higher speeds for the composite electrode sheet production apparatus result in higher production efficiency. However, excessively high speeds can easily lead to problems such as electrode sheet and solid electrolyte membrane breakage. This application does not specifically require the residence time of the electrode sheet and solid electrolyte membrane within the gap between the sizing rollers. Adjustments to the residence time that do not require inventive effort, provided they do not violate the inventive concept of this application, should be understood to fall within the scope of protection of this application.

[0390] In some embodiments, the linear speeds of the first shaping roller assembly and the second shaping roller assembly are kept consistent, and the linear speed of the electrode sheet unwinding mechanism 11 and the linear speed of the composite sheet winding mechanism 12 are also kept consistent, thereby improving the consistency of the entire composite sheet rolling preparation process and improving the consistency of the composite sheet.

[0391] 15-16 , in combination with the structure of the composite electrode sheet preparation device, the composite electrode sheet preparation method of the present application includes the following steps: unwinding the electrode sheet through the electrode sheet unwinding mechanism 11 and conveying the electrode sheet to the composite electrode sheet winding mechanism 12 , while unwinding the first solid electrolyte membrane through the first solid electrolyte membrane unwinding mechanism 25 ; the electrode sheet and the first solid electrolyte membrane first arrive at the first heater for heating, and then the electrode sheet and the first solid electrolyte membrane continue to advance to the first shaping roller assembly, and form a composite membrane sheet under the rolling action of the first shaping roller assembly; the composite membrane sheet moves to the second shaping roller assembly, and at the same time, the second solid electrolyte membrane unwinding mechanism unwinds the second solid electrolyte membrane, and the composite membrane sheet and the second solid electrolyte membrane arrive at the second heater, and after heating the second solid electrolyte membrane, arrive at the second shaping roller assembly, and form a composite electrode sheet under the action of the second shaping roller assembly, and the composite electrode sheet winding mechanism completes the winding.

[0392] This application divides the process of composite solid electrolyte membrane on both sides of the pole piece into two steps through the first shaping roller assembly and the second shaping roller assembly. Different process temperatures can be set according to the characteristics of the solid electrolyte membrane on both sides of the pole piece, thereby improving the composite effect of the pole piece and the solid electrolyte membrane.

[0393] In some embodiments, at least one of the first shaping roller assembly and the second shaping roller assembly is configured as an elastic rolling assembly; the elastic rolling assembly includes a rigid roller and an elastic roller having a lower hardness than the rigid roller, and the connecting line between the axes of the rigid roller and the elastic roller is perpendicular to the conveying direction of the electrode sheet.

[0394] In some embodiments, the solid electrolyte membrane is formed independently, meaning that the solid electrolyte membrane can be formed and maintained intact without the aid of a substrate. In this case, after the electrode sheet and the first solid electrolyte membrane enter the gap of the first sizing roller assembly, they are pressed by the first sizing roller assembly to form a composite membrane sheet. After the composite membrane sheet and the second solid electrolyte membrane advance into the gap of the second sizing roller assembly, they are pressed by the second sizing roller assembly to form a composite electrode sheet. Finally, the composite electrode sheet is wound by the electrode sheet winding mechanism 12.

[0395] In some embodiments, the solid electrolyte membrane is covered with a substrate to provide support for the solid electrolyte membrane. When the first solid electrolyte membrane unwinding mechanism 25 conveys the first solid electrolyte membrane, the first substrate is positioned on the side of the first solid electrolyte membrane away from the electrode sheet. When the second solid electrolyte membrane unwinding mechanism 23 conveys the second solid electrolyte membrane, the second substrate is positioned on the side of the second solid electrolyte membrane away from the electrode sheet. After the first solid electrolyte membrane and the electrode sheet are fully composited, the first substrate is separated from the composite membrane sheet. After the second solid electrolyte membrane and the composite membrane sheet are fully composited, the second substrate is separated from the composite membrane sheet. Specifically, the first substrate can be received by a first substrate rewinding mechanism 26 located on the same side of the electrode sheet as the first solid electrolyte membrane unwinding mechanism 25, and the first substrate rewinding mechanism 26 is located between the first and second sizing roller assemblies. The second substrate can be received by a second substrate rewinding mechanism 24 located on the same side of the electrode sheet as the second solid electrolyte membrane unwinding mechanism 23, and the second substrate rewinding mechanism 24 is located between the second sizing roller assembly and the composite electrode sheet rewinding mechanism 12.

[0396] In some embodiments, after the second shaping roller assembly completes rolling and before the composite electrode sheet winding mechanism winds up, a thickness measuring mechanism is used to inspect the composite electrode sheet, and the composite electrode sheet is wound up by the winding mechanism after passing the inspection.

[0397] Referring to FIG. 14 , FIG. 14 shows a flow chart of a method for preparing a composite electrode sheet using the composite electrode sheet preparation device of the present application, comprising:

[0398] S11: heating the electrode plate and the first solid electrolyte membrane by a first heater;

[0399] S12: Compounding the heated electrode sheet and the first solid electrolyte membrane through a first shaping roller assembly to obtain a composite membrane;

[0400] S13: heating the second solid electrolyte membrane by a second heater;

[0401] S14: Compounding the heated second solid electrolyte membrane and the composite membrane through a second shaping roller assembly to obtain a composite electrode.

[0402] At least one of the first and second shaping roller assemblies is configured as an elastic rolling assembly. The elastic rolling assembly includes a rigid roller and an elastic roller having a lower hardness than the rigid roller. The elastic roller faces the first solid electrolyte membrane or the second solid electrolyte membrane for lamination. During the rolling process, the elastic roller adjusts the force applied to the electrode sheet and the solid electrolyte membrane, ensuring that the solid electrolyte membrane better covers the electrode sheet after rolling. Furthermore, the lateral thickness of the electrode sheet tends to be consistent after rolling.

[0403] It is understood that in step S13, while the second heater is heating the second solid electrolyte membrane, the second heater can also heat the composite membrane formed by rolling the electrode sheet and the first solid electrolyte membrane. It is understood that in the rolled composite electrode sheet, the solid electrolyte layer is composited onto the electrode sheet. The solid electrolyte membrane located on both sides of the electrode sheet means that the solid electrolyte membrane is composited on both sides of the electrode sheet by the roller.

[0404] The composite process of this application is carried out under dry conditions. This dry process is different from the traditional wet electrode preparation method. The traditional wet method of preparing composite electrodes is to first prepare a solid electrolyte slurry and then apply the solid electrolyte slurry to the electrode plate, or vice versa, to prepare an electrode slurry and then apply the electrode slurry to the solid electrolyte membrane. The preparation process of this application does not use solvents, eliminating the tedious subsequent drying step, which can effectively reduce production costs.

[0405] It can be understood that the dry process means that no solvent is added during the preparation of the relevant electrode plates and electrolyte membranes; the technical solutions of trace amounts of liquid lubricants or other liquid additives that may be used during the rolling process should still be within the scope of protection of this application.

[0406] In some embodiments, the electrode plates and the solid electrolyte membrane are both prepared by a dry process.

[0407] In some embodiments, at least one of the electrode sheet and the solid electrolyte membrane is prepared by a dry process.

[0408] In some embodiments, the electrode plates and the solid electrolyte membrane are both prepared by a wet process.

[0409] It is understandable that the electrode plates and solid electrolyte membranes are preferably prepared under dry conditions, so that no solvent is required during the entire electrode preparation process.

[0410] It is understandable that the preparation process of the electrode sheet and the solid electrolyte membrane is independent of the preparation process of the composite electrode, that is, if a wet process is used, the electrode sheet undergoes coating, drying, and rolling processes.

[0411] In some embodiments, the electrode sheet is a positive electrode sheet; in some embodiments, the electrode sheet is a negative electrode sheet; in some embodiments, a solid electrolyte membrane is composited on one or both sides of the positive electrode sheet or the negative electrode sheet. The material composition, preparation method, and related performance parameters of the positive electrode sheet, the negative electrode sheet, and the solid electrolyte membrane have been fully described in the above embodiments of this application and will not be repeated here.

[0412] As mentioned in the background technology, the dry preparation method is that the traditional shaping roller assembly has high strength and poor deformation resistance, and the electrode plates are chamfered to ensure the smooth rolling process, forming a structure that is thick in the middle and thin at both ends. As shown in Figure 2, due to the inconsistent lateral thickness of the electrode plate 1, when the solid electrolyte membrane 2 is attached to the electrode plate 1, the edge area of ​​the electrode plate 1 is still separated from the solid electrolyte membrane. When the rolling equipment rolls the electrode plate 1 and the solid electrolyte membrane 2 for composite, the middle area and the edge area of ​​the electrode plate 1 are subjected to different rolling forces of the steel roller, making it difficult for the electrode plate 1 and the solid electrolyte membrane 2 to be tightly composited, that is, invalid composite, resulting in inconsistent lateral compaction density of the composite plate, and poor consistency of the composite plate. In severe cases, the electrode plate may break, which has a great impact on the safety performance and quality of the lithium-ion battery.

[0413] The preparation method of the present application utilizes the buffer provided by the elastic roller in the elastic rolling assembly during rolling by the shaping roller assembly, so that the solid electrolyte membrane can better cover the electrode sheet; at the same time, during the rolling process of the shaping roller assembly, the electrode sheet is thick in the middle, resulting in the force in the middle area of ​​the electrode sheet being greater than the edge area. After rolling, the lateral thickness of the electrode sheet tends to be consistent, as shown in Figure 3. This avoids, to a certain extent, the adverse effects of the rolling composite process caused by the phenomenon that the electrode sheet 1 is thick in the middle and thin at both ends, protecting the electrode sheet 1 from being crushed while also enabling a better combination between the active material layer in the electrode sheet 1 and the solid electrolyte membrane 2. In addition, during the rolling process of the shaping roller assembly, the electrode sheet 1 and the solid electrolyte membrane 2 can be pressed evenly under force, thereby improving the compaction density of the composite sheet, ensuring the consistency of the thickness of the composite sheet, weakening the phenomenon that the electrode sheet 1 is thick in the middle and thin at both ends, improving the quality of continuous rolling, and can be used for large-scale production.

[0414] Applying a solid electrolyte coating to the electrode surface, especially the high-capacity positive electrode, can effectively improve battery safety. However, due to energy density limitations, the thickness of the solid electrolyte membrane is typically thin. Compared with dry-process electrode sheets, the thickness of the solid electrolyte membrane is an order of magnitude smaller, making the solid electrolyte membrane susceptible to cracking during dry-process composite electrode sheets.

[0415] In some embodiments, the solid electrolyte membrane is formed independently, that is, the solid electrolyte membrane can be formed and maintain integrity without the aid of a substrate.

[0416] In some embodiments, the side of the solid electrolyte membrane away from the electrode plate is covered with a substrate, and the bonding strength between the substrate and the solid electrolyte membrane is weaker than the bonding strength between the solid electrolyte membrane and the electrode plate. After rolling, at least a portion of the solid electrolyte is transferred to the electrode and separated from the substrate.

[0417] This application does not specifically limit the type of substrate. Without violating the inventive concept of this application, any known material that has a certain supporting effect, can be more conducive to the formation of the electrolyte material film, and can be separated from the solid electrolyte membrane after rolling can be used in this application. As an illustrative example only, and not any limitation on 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 film, PE / PP film, PP / PE / PP film, PE / PP / PE film, and non-silicone release film. This application also provides a composite electrode, which is prepared according to the composite electrode preparation method provided above.

[0418] In one embodiment, the first solid electrolyte membrane and the second solid electrolyte membrane have different compositions.

[0419] Furthermore, the temperature of the first heater is different from the temperature of the second heater and / or the pressure of the first shaping roller is different from the pressure of the second shaping roller.

[0420] It is understood that the different compositions of the first and second solid electrolyte membranes can be understood as different material systems or structural compositions of the solid electrolyte membranes. This difference results in different composite processes for the first and second solid electrolyte membranes. The present application utilizes two composite processes, one before the other, to tailor different composite processes to the performance of the first and second solid electrolyte membranes with the positive electrode sheet.

[0421] In some embodiments, the elastic roller is configured to wrap around and cover the elastic member outside the rigid roller. When the elastic roller rotates, the elastic member rotates with the elastic roller. Furthermore, when the shaping roller assembly rolls the first solid electrolyte membrane, the electrode sheet, and the second solid electrolyte membrane, the elastic member provides a cushioning effect, allowing the first and second solid electrolyte membranes to better cover both sides of the electrode sheet, while also improving the consistency of the transverse thickness of the electrode sheet after rolling.

[0422] It is understandable that during the production of electrode sheets, in order to ensure the smooth progress of the subsequent rolling process, the edges of the electrode sheets are usually thinned, and the existence of the thinned area of ​​the electrode sheets affects the fit between the solid electrolyte membrane and the electrode sheets; if the electrode sheets and the solid electrolyte membrane cannot form an effective composite in the thinned area, the formed composite sheets are prone to form cracks in the edge area.

[0423] Surprisingly, the composite electrode preparation device of the present application uses the buffer provided by the elastic parts during rolling, so that the solid electrolyte membrane can better cover the electrode electrode; at the same time, during the rolling process of the shaping roller assembly, the electrode electrode is thick in the middle, resulting in the force in the middle area of ​​the electrode electrode being greater than the edge area, and the lateral thickness of the electrode electrode tends to be consistent after rolling.

[0424] The elastic part is made of a flexible material, which undergoes elastic deformation under pressure. The tiny elastic deformation makes the thickness of the middle area and the thinned area of ​​the electrode plate tend to be consistent under pressure, so that it can better fit with the solid electrolyte membrane.

[0425] The yield limit of the elastic member satisfies the following conditions: when the solid electrolyte membrane and the electrode plate pass through the gap between the shaping rollers, the solid electrolyte membrane and the electrode plate undergo plastic deformation, while the deformation of the elastic member undergoes elastic deformation.

[0426] Elastic deformation refers to the change in the relative positions of points on a solid due to the action of external force. When the external force is removed, the solid returns to its original shape, which is called elastic deformation.

[0427] When an object is subjected to a large force outside its elastic limit, it may break, deform, and be unable to return to its original shape. This phenomenon is called plastic deformation.

[0428] In some embodiments, the width of the elastic member is greater than or equal to the minimum width of the solid electrolyte membrane or the electrode sheet.

[0429] In some embodiments of the present application, the flexible material is a polymer. This application does not impose any particular restrictions on the polymer's material. For example, it can be plastics such as polytetrafluoroethylene, polyethylene terephthalate, polypropylene, and polyacrylonitrile; rubbers such as Hypalon rubber, silicone rubber, and fluororubber; or elastic materials such as silicone rubber that can deform to a certain degree. A hard rubber with high heat resistance is preferred.

[0430] The present application does not particularly limit the thickness of the elastic member. Any necessary adjustment to the thickness of the elastic member without violating the inventive concept of the present application can be understood as being within the scope of protection of the present application.

[0431] In some embodiments, the elastic roller can also be configured to partially surround and cover the elastic member outside the rigid roller, so that when the sizing roller assembly is rolled and laminated, the elastic member is located between the first or second solid electrolyte membrane and the sizing roller assembly. For example, the first elastic roller 35 can be replaced by a rigid roller in combination with a protective film made of a flexible material. The protective film can be unwound through the gap in the first sizing roller assembly by a protective film unwinding mechanism located between the first heater 77 and the first elastic roller 35. The first sizing roller assembly is arranged from top to bottom in the following order: the rigid roller, the protective film, the first solid electrolyte membrane, the electrode sheet, and the rigid roller. During rolling, the protective film replaces the elastic member in the first elastic roller and acts as a buffer.

[0432] The present application further provides a lithium-ion battery, which includes the composite electrode provided above.

[0433] In some embodiments, the electrode plates and solid electrolyte membranes may also be purchased.

[0434] In one embodiment of the present application, the following steps are included.

[0435] 1. Preparation of positive electrode sheet

[0436] Lithium manganese oxide is selected as the positive electrode active material, Ketjen black is used as the conductive agent, and PTFE is used as the binder. These materials are mixed and stirred in a high-speed blender to produce a positive electrode mixture. This mixture is then subjected to a jet milling process to fiberize the positive electrode mixture, i.e., the positive electrode active material layer. This positive electrode active material layer is then composited with a current collector by roller pressing to produce a positive electrode sheet.

[0437] 2. Preparation of solid electrolyte membrane

[0438] LLZO was selected as the solid electrolyte, polytetrafluoroethylene as the binder, and LiPF6 as the lithium salt. The above substances were mixed and stirred using a high-speed stirrer to obtain a solid electrolyte mixture. The mixture was then fiberized by air jet milling to obtain a fiberized solid electrolyte mixture. The fiberized solid electrolyte mixture was then rolled to obtain a solid electrolyte membrane.

[0439] 3. Preparation of composite positive electrode sheet

[0440] The positive electrode sheet and the first and second solid electrolyte membranes are composited using a composite electrode sheet preparation apparatus provided with a protective film as shown in Figure 15. The elastic member is Hypalon rubber, and the first flat heater is a radiant heater.

[0441] The first solid electrolyte membrane originates from the first solid electrolyte membrane unwinding mechanism 25, passes through the first guide roller 51, and then meets and bonds with the electrode sheet originating from the electrode sheet unwinding mechanism 11 at the second guide roller 52. The electrode sheet and the first solid electrolyte membrane pass through the first heater 77 before arriving at the first sizing roller assembly for the first lamination. The electrode sheet is further away from the first elastic roller 35 than the first solid electrolyte membrane. After lamination is completed, the first substrate is subjected to the force transmitted by the first substrate winding mechanism 26 via the third guide roller 53 and the fourth guide roller 54, causing the first substrate to separate from the composite membrane between the third guide roller 53 and the fifth guide roller 55, and then be rewound by the first substrate winding mechanism 26.

[0442] The second solid electrolyte membrane originates from the second solid electrolyte membrane unwinding mechanism 23, passes through the sixth guide roller 56, and then meets and bonds with the composite membrane sheet behind the seventh guide roller 57. The composite membrane originates from the first sizing roller assembly, separates from the first substrate, and then bonds with the second solid electrolyte membrane at the seventh guide roller 57. The electrode sheet and the second solid electrolyte membrane pass through the second heater 78 before arriving at the second sizing roller assembly for a second lamination, where the composite membrane sheet is further away from the second elastic roller 34 than the second solid electrolyte membrane. After lamination, the second substrate is separated from the composite electrode sheet by the force transmitted by the second substrate rewinding mechanism 24 via the ninth and eighth guide rollers 59, 58, and finally rewound by the second substrate rewinding mechanism 24. As shown in Figure 15, the eighth guide roller 58 is located immediately adjacent to the path of the composite electrode sheet, and the second substrate has an S-shaped path between the eighth and ninth guide rollers 58, 59. The composite electrode sheet is adjusted in direction by the eleventh guide roller 61 and the twelfth guide roller 62 , and then cooled by the first cooling roller 75 and the second cooling roller 76 , and finally wound up by the composite electrode sheet winding mechanism 12 .

[0443] The temperature of the first shaping roller and the first heater is 160°C, and the temperature of the second shaping roller and the second heater is 180°C.

[0444] The prepared composite pole piece has no cracks on its surface and the overall thickness of the composite pole piece is 160 μm.

[0445] In one embodiment of the present application, the following steps are included.

[0446] 1. Preparation of positive electrode sheet

[0447] Lithium manganese oxide is selected as the positive electrode active material, Ketjen black is used as the conductive agent, and PTFE is used as the binder. These materials are mixed and stirred in a high-speed blender to produce a positive electrode mixture. This mixture is then subjected to a jet milling process to fiberize the positive electrode mixture, i.e., the positive electrode active material layer. This positive electrode active material layer is then composited with a current collector by roller pressing to produce a positive electrode sheet.

[0448] 2. Preparation of solid electrolyte membrane

[0449] A preselected solid electrolyte material is selected and polytetrafluoroethylene is used as a binder. The above materials are mixed and stirred using a high-speed stirrer to obtain a solid electrolyte mixture. The mixture is then fiberized by mechanical stirring to obtain a fiberized solid electrolyte mixture. The fiberized solid electrolyte mixture is then rolled to produce a solid electrolyte membrane.

[0450] Among them, the raw materials of the first solid electrolyte membrane are LLZO and PTFE particles, the stirring speed of the fiberization process is 12000rpm, and the preset thickness is 15μm; the raw materials of the second solid electrolyte membrane are LLZO and PTFE fiber membrane, the stirring speed of the fiberization process is 8000rpm, and the preset thickness is 17μm.

[0451] 3. Preparation of composite positive electrode sheet

[0452] The positive electrode sheet and the first and second solid electrolyte membranes were composited using the composite electrode sheet preparation apparatus equipped with a protective film as shown in Figure 16. The elastic member was Hypalon rubber. Unlike the previous embodiment, the separation angle was not controlled when separating the first substrate from the composite membrane, or when separating the second substrate from the composite electrode sheet.

[0453] The first solid electrolyte membrane originates from the first solid electrolyte membrane unwinding mechanism 25, passes through the first guide roller 51, and then meets and bonds with the electrode sheet originating from the electrode sheet unwinding mechanism 11 at the second guide roller 52. The electrode sheet and the first solid electrolyte membrane pass through the first heater 77 before arriving at the first sizing roller assembly for the first lamination. The electrode sheet is further away from the first elastic roller 35 than the first solid electrolyte membrane. After lamination is completed, the first substrate is subjected to the force transmitted by the first substrate winding mechanism 26 via the third guide roller 53 and the fourth guide roller 54, causing the first substrate to separate from the composite membrane between the third guide roller 53 and the fifth guide roller 55, and then be rewound by the first substrate winding mechanism 26.

[0454] The second solid electrolyte membrane originates from the second solid electrolyte membrane unwinding mechanism 23, passes through the sixth guide roller 56, and then meets and bonds with the composite membrane sheet behind the seventh guide roller 57. The composite membrane originates from the first shaping roller assembly, separates from the first substrate, and then bonds with the second solid electrolyte membrane at the seventh guide roller 57. The electrode sheet and the second solid electrolyte membrane pass through the second heater 78 before arriving at the second shaping roller assembly for a second bonding. The composite membrane sheet is further away from the second elastic roller 34 than the second solid electrolyte membrane. The temperature of the first shaping roller and the first heater is 160°C, and the temperature of the second shaping roller and the second heater is 180°C.

[0455] After lamination is complete, the second substrate moves along with the composite electrode sheet toward the composite electrode sheet reeling mechanism 12. Simultaneously, the second substrate is subjected to the force transmitted by the second substrate reeling mechanism 24 via the ninth guide roller 59 and the eighth guide roller 58, separating from the composite electrode sheet at the eighth guide roller 58. After passing around the same side of the eighth and ninth guide rollers 58 and 59, the second substrate is finally reeled by the second substrate reeling mechanism 24. The eighth guide roller 58 is located immediately adjacent to the composite electrode sheet's path. The composite electrode sheet is cooled by the first and second cooling rollers 75 and 76 before being reeled by the composite electrode sheet reeling mechanism 12.

[0456] The prepared composite pole piece has no cracks on its surface and the overall thickness of the pole piece is 165 μm.

[0457] Another aspect of the present application provides a composite electrode preparation method to improve the composite effect of dry composite electrode sheets and solid electrolyte membranes. Referring to Figures 18-19, the composite electrode preparation device for preparing the composite electrode sheets of the present application includes an electrode sheet unwinding mechanism, a first solid electrolyte membrane unwinding mechanism, a second solid electrolyte membrane unwinding mechanism, a first heating roller assembly, a second heating roller assembly, a first shaping roller assembly, a second shaping roller assembly, and a composite electrode sheet winding mechanism. The first shaping roller assembly is located upstream of the second shaping roller assembly, and at least one of the first shaping roller assembly and the second shaping roller assembly is configured as an elastic rolling assembly; the elastic rolling assembly includes a rigid roller and an elastic roller having a lower hardness than the rigid roller. The connecting line between the rigid roller and the elastic roller axis is perpendicular to the conveying direction of the electrode sheet, that is, the conveying direction of the electrode sheet is perpendicular to the plane where the axis of the rigid roller and the axis of the elastic roller are located. However, this is not limited to this. The conveying direction of the electrode sheet can be adaptively adjusted according to actual production needs.

[0458] In some embodiments, the first shaping roller assembly and the second shaping roller assembly each include two rollers symmetrically arranged on both sides of the electrode sheet, and the connecting line between the axes of the two rollers is perpendicular to the conveying direction of the electrode sheet.

[0459] Optionally, the first shaping roller assembly includes a rigid roller and an elastic roller; and the second shaping roller assembly includes two rigid rollers.

[0460] Alternatively, the first shaping roller assembly and the second shaping roller assembly each include a rigid roller and an elastic roller.

[0461] Alternatively, the first shaping roller assembly includes two rigid rollers; and the second shaping roller assembly includes a rigid roller and an elastic roller.

[0462] Preferably, both the first and second shaping roller assemblies include a rigid roller and an elastic roller. Exemplarily, as shown in FIG18 , the first shaping roller assembly includes a first rigid roller 36 and a first elastic roller 35 disposed opposite the first rigid roller 36 , with the first elastic roller 35 located on the side of the first solid electrolyte membrane away from the electrode pads. The second shaping roller assembly includes a second rigid roller 33 and a second elastic roller 34 disposed opposite the second rigid roller 33 , with the second elastic roller 34 located on the side of the second solid electrolyte membrane away from the electrode pads.

[0463] The first solid electrolyte membrane and electrode sheet are preheated before entering the first shaping roller assembly. After preheating, the first solid electrolyte membrane and electrode sheet soften compared to before preheating, improving their ductility. As a result, when the first shaping roller assembly rolls the first solid electrolyte membrane and electrode sheet, the first solid electrolyte membrane and electrode sheet interlock more tightly, increasing the bond strength between the two and further enhancing their composite effect. Similarly, the second solid electrolyte membrane and composite membrane are heated before entering the second shaping roller assembly, which also improves the composite effect between the second solid electrolyte membrane and the composite membrane, resulting in a composite electrode sheet with better composite effect.

[0464] Preferably, when a substrate is provided on the solid electrolyte membrane, the substrate covers a side of the solid electrolyte membrane away from the electrode plate.

[0465] In some embodiments, the first substrate is separated after the electrode sheet and the first solid electrolyte membrane are rolled by a first shaping roller assembly to obtain a composite membrane sheet.

[0466] Preferably, the first substrate is separated from the composite membrane by arranging a first substrate winding mechanism downstream between the first shaping roller assembly and the second shaping roller assembly, so as to improve the heating effect of the subsequent second heating roller assembly on the second solid electrolyte membrane, and also improve the composite effect between the composite membrane and the second solid electrolyte membrane; the first substrate winding mechanism and the first solid electrolyte membrane unwinding mechanism are located on the same side of the electrode sheet unwinding mechanism, and are used to receive the substrate covering the side of the first solid electrolyte away from the electrode sheet.

[0467] After the first solid electrolyte membrane and the electrode plate are composited, the substrate and the composite membrane are first separated by a substrate separation device, and then the composite membrane passes through the second heating roller assembly, avoiding the influence of the substrate on the composite membrane when it enters the second heating roller assembly.

[0468] When the second substrate needs to be separated after the composite membrane and the second solid electrolyte membrane are rolled by the second shaping roller assembly to form a composite electrode sheet, a second substrate rewinding mechanism is provided downstream of the second shaping roller assembly to achieve separation of the second substrate from the composite electrode sheet. The second substrate rewinding mechanism and the first substrate rewinding mechanism are located on either side of the electrode sheet unwinding mechanism and are used to receive the substrate covering the side of the second solid electrolyte away from the electrode sheet. During the separation process, the first and second substrate rewinding mechanisms respectively apply tension to the first and second substrates, separating the first and second substrates from the composite membrane or composite electrode sheet, and completing the substrate rewinding action when necessary.

[0469] Optionally, the first substrate winding mechanism is located between the first shaping roller assembly and the second shaping roller assembly.

[0470] Alternatively, the first substrate winding mechanism and the second substrate winding mechanism are both located downstream of the second shaping roller assembly, and are symmetrically arranged on both sides of the composite electrode winding mechanism.

[0471] In some embodiments, the elastic roller includes a rigid roller and an elastic member, with the elastic member covering the outer side of the rigid roller. When the elastic roller rotates, the elastic member rotates with the elastic roller. Furthermore, when the shaping roller assembly rolls the first solid electrolyte membrane, the electrode sheet, and the second solid electrolyte membrane, the elastic member provides a cushioning effect, allowing the first and second solid electrolyte membranes to better cover both sides of the electrode sheet, while also improving the consistency of the transverse thickness of the electrode sheet after rolling.

[0472] The present application does not particularly limit the thickness of the elastic member. Any necessary adjustment to the thickness of the elastic member without violating the inventive concept of the present application can be understood as being within the scope of protection of the present application.

[0473] In some embodiments, the elastic roller can also be configured to include a rigid roller and an elastic member, and the elastic member surrounds and covers the outside of a portion of the rigid roller, so that when the shaping roller assembly is rolled and composited, the elastic member is located between the first or second solid electrolyte membrane and the shaping roller assembly.

[0474] In some embodiments, the rigid rollers in the first and second shaping roller assemblies may be internally provided with a heating device to improve the lamination effect. The elastic roller may optionally be internally provided with a heating device.

[0475] The electrode sheet unwinding mechanism is located upstream of the first shaping roller assembly and the first heating roller assembly, and is used to unwind the electrode sheet, then transport the electrode sheet so that the electrode sheet reaches the first heating roller assembly for heating, and then continue to transport the heated electrode sheet to the gap in the middle of the first shaping roller assembly.

[0476] The first solid electrolyte membrane unwinding mechanism is located upstream of the first sizing roller assembly and the first heating roller assembly, more specifically, between the electrode sheet unwinding mechanism and the first heating roller assembly. The first solid electrolyte membrane unwinding mechanism is used to unwind the first solid electrolyte membrane, then transport the first solid electrolyte membrane to the first heating roller assembly for heating, and then transport the heated first solid electrolyte membrane to the gap between the first sizing roller assembly.

[0477] The second solid electrolyte membrane unwinding mechanism is located downstream of the first sizing roller assembly, more specifically, between the first sizing roller assembly and the second heating roller assembly. The second solid electrolyte membrane unwinding mechanism is used to unwind the second solid electrolyte membrane, then transport the second solid electrolyte membrane to the second heating roller assembly for heating, and then transport the heated second solid electrolyte membrane to the gap between the second sizing roller assembly.

[0478] In some embodiments, the first heating roller assembly and / or the second heating roller assembly may include multiple groups of heating rollers for heating at least one of the electrode sheet, the first solid electrolyte membrane, the second solid electrolyte membrane, and the composite membrane. Adaptively, a group of heating rollers may be located between the electrode sheet unwinding mechanism and the first shaping roller assembly for heating the electrode sheet. A group of heating rollers may be located between the first solid electrolyte membrane unwinding mechanism and the first shaping roller assembly for heating the electrode sheet and / or the first solid electrolyte membrane. A group of heating rollers may also be located between the first shaping roller assembly and the second shaping roller assembly for heating the composite membrane. A group of heating rollers may also be located between the second solid electrolyte membrane unwinding mechanism and the second shaping roller assembly for heating the composite membrane and / or the second solid electrolyte membrane.

[0479] It is understandable that the number of heating rollers in each group can be one or more; the heating behavior can be implemented by a single group of heating rollers, or by a combination of two or more groups of heating rollers. The number of heating rollers in each group of heating rollers, the relative positions between them, and the relative positions between multiple groups of heating rollers can all be adaptively adjusted as needed. For example, when it is necessary to adjust the heating time of the electrode sheet, a certain number of heating rollers can be set between the electrode sheet unwinding mechanism and the first shaping roller assembly, and the number of heating rollers can be increased or decreased according to the length of the required heating time; on the other hand, the position of the heating roller can be adjusted to change the wrap angle between the electrode sheet and the heating roller, thereby adjusting the heating time of the electrode sheet; or the above two methods can be combined to adjust the heating time of the electrode sheet.

[0480] In some embodiments, the heating time of the heating rollers in each group of heating rollers is the same or different. The heating time of each heating roller depends on actual production requirements and is not specifically limited.

[0481] In this application, the process of composite solid electrolyte membranes on both sides of the electrode plates is divided into two steps. The corresponding solid electrolyte membranes and process characteristics in the two steps are different, and the heating time of the heating roller is also adjusted accordingly to improve the bonding strength and composite effect between the electrode plates and the solid electrolyte membrane.

[0482] In some embodiments, the heating roller may be an electrically heated heating roller or a fluid heated heating roller.

[0483] The multiple heating rollers of each group of heating rollers can be set as upper and lower pairs of rollers, so that the electrode plate moves forward in an S-shaped path between the two heating rollers. As shown in Figure 18, the electrode plate first reaches the left side of the first heating roller 71, rotates around the first heating roller 71 for a certain angle, and then separates from the first heating roller 71 from the right side of the first heating roller 71. After moving to the left side of the second heating roller 72, it continues to rotate around the second heating roller 72 for a certain angle and then separates from the second heating roller 72 from the right side of the second heating roller 72, thereby increasing the contact area between the electrode plate and the heating roller, and improving the heating effect without expanding the space occupied by the device.

[0484] In some embodiments, the heating temperatures of the heating rollers in the first heating roller assembly are the same or different, and the temperature of each heating roller may be determined according to the material properties and process requirements of the electrode plate or solid electrolyte membrane it contacts. For example, as shown in FIG18 , since the process of composite solid electrolyte membranes on both sides of the electrode plate is divided into two steps, for the composite membrane, its contact surface when passing through the fourth heating roller 79 is the first solid electrolyte membrane, and the first solid electrolyte membrane has been pressed with the electrode plate; and when the composite membrane passes through the third heating roller 73, the contact surface is the second solid electrolyte membrane, and the second solid electrolyte membrane has not yet been pressed with the composite membrane. The material properties and process nodes corresponding to the third heating roller 73 and the fourth heating roller 79 are different, and therefore their corresponding heating temperatures also need to be adaptively set to obtain a better composite effect between the electrode plate and different solid electrolyte membranes.

[0485] In some embodiments, the heating temperatures of the heating rollers in the second heating roller assembly are the same or different. It can be understood that, similar to the first heating roller assembly, the temperature of each heating roller in the second heating roller assembly can be determined based on the material properties and process requirements of the electrode plate or solid electrolyte membrane it contacts.

[0486] In a preferred embodiment, the temperature of each heating roller is higher than the softening temperature of the electrode plate and the solid electrolyte membrane.

[0487] It can be understood that the softening temperature of the above-mentioned electrode plates and solid electrolyte membranes refers to the temperature above which the surface hardness of the electrode plates or solid electrolyte membranes changes, and the electrode plates and solid electrolyte membranes form a complete composite structure under the action of rolling pressure.

[0488] It can be seen that the composite electrode preparation method of the present application performs characteristic control on the heating temperature and heating time of the relevant heating rollers according to factors such as the process characteristics of different processes and the material characteristics of each process node, so as to obtain better bonding strength and composite process between the electrode electrode and the first solid electrolyte membrane and the second solid electrolyte membrane, which is suitable for the production requirements of different composite electrodes.

[0489] In some embodiments, the heating roller further includes a sensor for detecting the surface temperature of the roller body to obtain the temperature of the composite diaphragm or the composite pole piece.

[0490] The composite electrode sheet winding mechanism is located downstream of the second shaping roller assembly, and is used to provide tension to the electrode sheet along the direction of movement of the electrode sheet, and receive the composite electrode sheet obtained after being rolled by the second shaping roller assembly to complete the winding action.

[0491] In some embodiments, the composite electrode preparation device further includes a substrate winding mechanism.

[0492] In some embodiments, the composite electrode sheet production apparatus further includes a cooling roller, located downstream of the second shaping roller assembly, for cooling the composite electrode sheet. This application improves production efficiency by providing a cooling roller to reduce the temperature of the composite electrode sheet; the cooling roller also provides a shaping effect for the composite electrode sheet.

[0493] The number of cooling rollers may be one or more, preferably two.

[0494] Preferably, the cooling roller of the present application adopts a contact cooling roller, which has a better cooling effect.

[0495] The relative positions of the cooling rollers can be determined according to requirements and are not limited.

[0496] In some embodiments, the cooling roller further includes a sensor for detecting the surface temperature of the roller body to obtain the temperature of the composite pole piece.

[0497] In some embodiments, the composite pole piece preparation device further includes a guide roller.

[0498] Optionally, a guide roller is located between the first solid electrolyte membrane unwinding mechanism and the first shaping roller assembly to provide guidance for the first solid electrolyte membrane and / or the electrode sheet. As shown in Figure 18, the first solid electrolyte membrane starts from the first solid electrolyte membrane unwinding mechanism 25, passes through the first guide roller 51, and then meets and fits with the electrode sheet starting from the electrode sheet unwinding mechanism 11 at the second guide roller 52. The electrode sheet and the first solid electrolyte membrane pass through the second guide roller 52 and the third guide roller 53 and then arrive at the first heating roller 71. After rotating around the first heating roller 71 for a certain angle, the electrode sheet and the first solid electrolyte membrane arrive at the second heating roller 72, and after rotating around the second heating roller 72 for a certain angle, they move forward to the first shaping roller assembly for the first compounding.

[0499] By adjusting the relative position between the guide roller and the heating roller, the heating time of the electrode sheet and / or the first solid electrolyte membrane can be adjusted. For example, by adjusting the third guide roller 53 in FIG. 18 while maintaining its longitudinal position and moving it upward, the heating time of the electrode sheet and the first solid electrolyte membrane can be shortened, or by adjusting the third guide roller 53 while maintaining its longitudinal position and moving it downward, the heating time of the electrode sheet and the first solid electrolyte membrane can be lengthened. Preferably, the electrode sheet and the first solid electrolyte membrane are rotated at a large angle around the heating roller to achieve higher heating efficiency within the same space.

[0500] In some embodiments, the heating time of the first heating roller assembly and / or the second heating roller assembly is ≥2s.

[0501] Optionally, a guide roller is located between the first sizing roller assembly and the first substrate winding mechanism 26 to guide the first substrate of the first solid electrolyte membrane after it is separated from the composite electrode sheet. As shown in Figure 18, after the electrode sheet and the first solid electrolyte membrane are combined to form a composite membrane sheet at the first sizing roller assembly, the composite membrane continues to move toward the second sizing roller assembly. Under the action of the first substrate winding mechanism 26, the first substrate rotates a certain angle along the first elastic roller 35 in the first sizing roller assembly, then advances to the fourth guide roller 54, where it is wound by the first substrate winding mechanism 26.

[0502] Optionally, a guide roller is located between the second solid electrolyte membrane unwinding mechanism 23 and the second shaping roller assembly to provide guidance for the second solid electrolyte membrane and / or composite membrane. As shown in Figure 18, the second solid electrolyte membrane departs from the second solid electrolyte membrane unwinding mechanism 23, passes through the fifth guide roller 55, and then meets and bonds with the composite membrane at the sixth guide roller 56. The composite membrane and the second solid electrolyte membrane pass through the sixth guide roller 56 and the seventh guide roller 57 before arriving at the third heating roller 73. After rotating around the third heating roller 73 for a certain angle, the composite membrane and the second solid electrolyte membrane arrive at the fourth heating roller 79. After rotating around the fourth heating roller 79 for a certain angle, they proceed to the second shaping roller assembly for a second lamination.

[0503] Optionally, a guide roller is located between the second shaping roller assembly and the second substrate reeling mechanism 24 to guide the second substrate of the second solid electrolyte membrane after it is separated from the composite electrode sheet. As shown in Figure 18, after the composite membrane sheet and the second solid electrolyte membrane are combined at the second shaping roller assembly to form a composite electrode sheet, the composite electrode sheet continues to move toward the composite electrode sheet reeling mechanism 12. Under the action of the second substrate reeling mechanism 24, the second substrate rotates a certain angle along with the second elastic roller 34 in the second shaping roller assembly, then advances to the ninth guide roller 59, where it is reeled by the second substrate reeling mechanism 24.

[0504] Optionally, a guide roller is located between the second shaping roller assembly and the composite electrode sheet winding mechanism 12 to provide guidance for the composite electrode sheet. As shown in FIG18 , after the composite membrane and the second solid electrolyte membrane are combined at the second shaping roller assembly to form a composite electrode sheet, the composite electrode sheet continues to move toward the composite electrode sheet winding mechanism 12. The composite electrode sheet first reaches the eighth guide roller 58 and rotates around it for a certain angle before reaching the first cooling roller 75. The composite electrode sheet rotates around the first cooling roller 75 for a certain angle before reaching the second cooling roller 76. After rotating around the second cooling roller 76 for a certain angle, it moves forward to the composite electrode sheet winding mechanism 12 and completes the composite electrode sheet winding action. If necessary, a tenth guide roller 60 can also be provided between the second cooling roller 76 and the composite electrode sheet winding mechanism 12 to adjust the direction of the composite electrode sheet.

[0505] In some embodiments, the composite electrode sheet preparation apparatus further includes a tension control device, an unwinding correction assembly, and an electrode sheet static elimination assembly, sequentially arranged along its unwinding path. The tension control device includes multiple tension control elements positioned upstream of the roller pressing device, each for controlling the unwinding tension of the positive electrode sheet and the solid electrolyte membrane. Optionally, the tension control device includes multiple tension control elements positioned downstream of the roller pressing device, each for controlling the rewinding tension of the composite positive electrode sheet and the substrate. The unwinding correction assembly corrects the unwinding and running paths of the electrode sheet and the solid electrolyte membrane, ensuring that the starting material line remains at the same level. The unwinding and rewinding mechanism for the main material utilizes a single-station correction mechanism, while the unwinding and rewinding mechanism for the remaining materials utilizes a cantilever mechanism, both with correction. The static elimination assembly performs static elimination on both sides of the electrode sheet, reducing friction between the electrode sheet and the conveyor rollers. It is understood that, without departing from the inventive concept of this application, known functional components or structures throughout the entire process from rewinding, rolling, and unwinding can be used in this application.

[0506] In some embodiments, the width of the first and second shaping roller assemblies is 500-800 mm, including but not limited to 500 mm, 550 mm, 600 mm, 650 mm, 700 mm, 750 mm, and 800 mm, preferably 550-650 mm.

[0507] In some embodiments, the roller diameters of the first and second shaping roller assemblies are 300-500 mm, including but not limited to 300 mm, 350 mm, 400 mm, 450 mm, and 500 mm, preferably 350-450 mm.

[0508] In some embodiments, the mechanical speed of the sizing roller assembly is 5-60 m / min, including but not limited to 5 m / min, 10 m / min, 20 m / min, 30 m / min, 40 m / min, 45 m / min, 50 m / min, and 60 m / min.

[0509] It is understood that higher speeds for the composite electrode sheet production apparatus result in higher production efficiency. However, excessively high speeds can easily lead to problems such as electrode sheet and solid electrolyte membrane breakage. This application does not specifically require the residence time of the electrode sheet and solid electrolyte membrane within the gap between the sizing rollers. Adjustments to the residence time that do not require inventive effort, provided they do not violate the inventive concept of this application, should be understood to fall within the scope of protection of this application.

[0510] In some embodiments, the linear speeds of the first shaping roller assembly and the second shaping roller assembly are kept consistent, and the linear speed of the electrode sheet unwinding mechanism 11 and the linear speed of the composite sheet winding mechanism 12 are also kept consistent, thereby improving the consistency of the entire composite sheet rolling preparation process and improving the consistency of the composite sheet.

[0511] 18-19 , in combination with the structure of the composite electrode sheet preparation device, the composite electrode sheet preparation method of the present application includes the following steps: unwinding the electrode sheet through the electrode sheet unwinding mechanism 11 and conveying the electrode sheet to the composite electrode sheet winding mechanism 12 , and at the same time unwinding the first solid electrolyte membrane through the first solid electrolyte membrane unwinding mechanism 25 ; the electrode sheet and the first solid electrolyte membrane first arrive at the first heating roller assembly for heating, and then the electrode sheet and the first solid electrolyte membrane continue to advance to the first shaping roller assembly, and form a composite membrane sheet under the rolling action of the first shaping roller assembly; the composite membrane sheet moves to the second shaping roller assembly, and at the same time the second solid electrolyte membrane unwinding mechanism unwinds the second solid electrolyte membrane, the composite membrane sheet and the second solid electrolyte membrane arrive at the second heating roller assembly for heating and then arrive at the second shaping roller assembly, and form a composite electrode sheet under the action of the second shaping roller assembly, and the winding is completed by the composite electrode sheet winding mechanism 12 .

[0512] In some embodiments, at least one of the first shaping roller assembly and the second shaping roller assembly is configured as an elastic rolling assembly; the elastic rolling assembly includes a rigid roller and an elastic roller having a lower hardness than the rigid roller, and the connecting line between the axes of the rigid roller and the elastic roller is perpendicular to the conveying direction of the electrode sheet.

[0513] In some embodiments, the solid electrolyte membrane is formed independently, meaning that the solid electrolyte membrane can be formed and maintained intact without the aid of a substrate. In this case, after the electrode sheet and the first solid electrolyte membrane enter the gap of the first sizing roller assembly, they are pressed by the first sizing roller assembly to form a composite membrane sheet. After the composite membrane sheet and the second solid electrolyte membrane advance into the gap of the second sizing roller assembly, they are pressed by the second sizing roller assembly to form a composite electrode sheet. Finally, the composite electrode sheet is wound by the electrode sheet winding mechanism 12.

[0514] In some embodiments, the solid electrolyte membrane is covered with a substrate to provide support for the solid electrolyte membrane. When the first solid electrolyte membrane unwinding mechanism 25 conveys the first solid electrolyte membrane, the first substrate is positioned on the side of the first solid electrolyte membrane away from the electrode sheet. When the second solid electrolyte membrane unwinding mechanism 23 conveys the second solid electrolyte membrane, the second substrate is positioned on the side of the second solid electrolyte membrane away from the electrode sheet. After the first solid electrolyte membrane and the electrode sheet are fully composited, the first substrate is separated from the composite membrane sheet. After the second solid electrolyte membrane and the composite membrane sheet are fully composited, the second substrate is separated from the composite membrane sheet. Specifically, the first substrate can be received by a first substrate rewinding mechanism 26 located on the same side of the electrode sheet as the first solid electrolyte membrane unwinding mechanism 25, and the first substrate rewinding mechanism 26 is located between the first and second sizing roller assemblies. The second substrate can be received by a second substrate rewinding mechanism 24 located on the same side of the electrode sheet as the second solid electrolyte membrane unwinding mechanism 23, and the second substrate rewinding mechanism 24 is located between the second sizing roller assembly and the composite electrode sheet rewinding mechanism.

[0515] In some embodiments, after the second shaping roller assembly completes rolling and before the composite electrode sheet winding mechanism winds up, a thickness measuring mechanism is used to inspect the composite electrode sheet, and the composite electrode sheet is wound up by the winding mechanism after passing the inspection.

[0516] Refer to FIG17 , which shows a flow chart of a method for preparing a composite electrode sheet using the composite electrode sheet preparation device of the present application, including the following steps:

[0517] S21: heating the electrode sheet and the first solid electrolyte membrane by a first heating roller assembly;

[0518] S22: Compounding the heated electrode sheet and the first solid electrolyte membrane by a first shaping roller assembly to obtain a composite membrane;

[0519] S23: heating the composite membrane and the second solid electrolyte membrane by a second heating roller assembly;

[0520] S24: Compounding the heated composite membrane and the second solid electrolyte membrane through a second shaping roller assembly to obtain a composite electrode.

[0521] At least one of the first and second shaping roller assemblies is configured as an elastic rolling assembly. The elastic rolling assembly includes a rigid roller and an elastic roller having a lower hardness than the rigid roller. The elastic roller faces the first solid electrolyte membrane or the second solid electrolyte membrane for lamination. During the rolling process, the elastic roller adjusts the force applied to the electrode sheet and the solid electrolyte membrane, ensuring that the solid electrolyte membrane better covers the electrode sheet after rolling. Furthermore, the lateral thickness of the electrode sheet tends to be consistent after rolling.

[0522] 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 located on both sides of the electrode sheet, which means that both sides of the electrode sheet are composited with the solid electrolyte membrane by the rolling roller.

[0523] In addition, both S22 and S24 are carried out under dry conditions, that is, the composite process of this application is carried out under dry conditions. The dry conditions of this application are different from the traditional wet electrode preparation method. The traditional wet method for preparing composite electrodes is to first prepare a solid electrolyte slurry and then apply the solid electrolyte slurry to the electrode plate, or vice versa, prepare an electrode slurry and then apply the electrode slurry to the solid electrolyte membrane. No solvent is used in the preparation process of this application, which eliminates the tedious drying step in the subsequent steps and can effectively reduce production costs.

[0524] It can be understood that the dry process means that no solvent is added during the preparation of the relevant electrode plates and electrolyte membranes; the technical solutions of trace amounts of liquid lubricants or other liquid additives that may be used during the rolling process should still be within the scope of protection of this application.

[0525] In some embodiments, the electrode plates and the solid electrolyte membrane are both prepared by a dry process.

[0526] In some embodiments, at least one of the electrode sheet and the solid electrolyte membrane is prepared by a dry process.

[0527] In some embodiments, the electrode plates and the solid electrolyte membrane are both prepared by a wet process.

[0528] It is understandable that the electrode plates and solid electrolyte membranes are preferably prepared under dry conditions, so that no solvent is required during the entire electrode preparation process.

[0529] It is understandable that the preparation process of the electrode sheet and the solid electrolyte membrane is independent of the preparation process of the composite electrode, that is, if a wet process is used, the electrode sheet undergoes coating, drying, and rolling processes.

[0530] In some embodiments, the electrode sheet is a positive electrode sheet; in some embodiments, the electrode sheet is a negative electrode sheet; and in some embodiments, a solid electrolyte membrane is composited on one or both sides of the positive electrode sheet or the negative electrode sheet. The material composition, preparation method, and related performance parameters of the positive electrode sheet, the negative electrode sheet, and the solid electrolyte membrane can be referred to in the above embodiments of this application and will not be repeated here.

[0531] As mentioned in the background technology, the dry preparation method is that the traditional shaping roller assembly has high strength and poor deformation resistance, and the electrode plates are chamfered to ensure the smooth rolling process, forming a structure that is thick in the middle and thin at both ends. As shown in Figure 2, due to the inconsistent lateral thickness of the electrode plate 1, when the solid electrolyte membrane 2 is attached to the electrode plate 1, the edge area of ​​the electrode plate 1 is still separated from the solid electrolyte membrane. When the rolling equipment rolls the electrode plate 1 and the solid electrolyte membrane 2 for composite, the middle area and the edge area of ​​the electrode plate 1 are subjected to different rolling forces of the steel roller, making it difficult for the electrode plate 1 and the solid electrolyte membrane 2 to be tightly composited, that is, invalid composite, resulting in inconsistent lateral compaction density of the composite plate, and poor consistency of the composite plate. In severe cases, the electrode plate may break, which has a great impact on the safety performance and quality of the lithium-ion battery.

[0532] The preparation method of the present application utilizes the buffer provided by the elastic roller in the elastic rolling assembly during rolling by the shaping roller assembly, so that the solid electrolyte membrane can better cover the electrode sheet; at the same time, during the rolling process of the shaping roller assembly, the electrode sheet is thick in the middle, resulting in the force in the middle area of ​​the electrode sheet being greater than the edge area. After rolling, the lateral thickness of the electrode sheet tends to be consistent, as shown in Figure 3. This avoids, to a certain extent, the adverse effects of the rolling composite process caused by the phenomenon that the electrode sheet 1 is thick in the middle and thin at both ends, protecting the electrode sheet 1 from being crushed while also enabling a better combination between the active material layer in the electrode sheet 1 and the solid electrolyte membrane 2. In addition, during the rolling process of the shaping roller assembly, the electrode sheet 1 and the solid electrolyte membrane 2 can be pressed evenly under force, thereby improving the compaction density of the composite sheet, ensuring the consistency of the thickness of the composite sheet, weakening the phenomenon that the electrode sheet 1 is thick in the middle and thin at both ends, improving the quality of continuous rolling, and can be used for large-scale production.

[0533] Applying a solid electrolyte coating to the electrode surface, especially the high-capacity positive electrode, can effectively improve battery safety. However, due to energy density limitations, the thickness of the solid electrolyte membrane is typically thin. Compared with dry-process electrode sheets, the thickness of the solid electrolyte membrane is an order of magnitude smaller, making the solid electrolyte membrane susceptible to cracking during dry-process composite electrode sheets.

[0534] In some embodiments, the solid electrolyte membrane is formed independently, that is, the solid electrolyte membrane can be formed and maintain integrity without the aid of a substrate.

[0535] In some embodiments, the side of the solid electrolyte membrane away from the electrode plate is covered with a substrate, and the bonding strength between the substrate and the solid electrolyte membrane is weaker than the bonding strength between the solid electrolyte membrane and the electrode plate. After rolling, at least a portion of the solid electrolyte is transferred to the electrode and separated from the substrate.

[0536] The present application does not specifically limit the type of substrate. Without violating the inventive concept of the present application, any known material with a certain supporting effect, which can be more conducive to the film formation of the electrolyte material and can be separated from the solid electrolyte membrane after rolling can be used in the present application; it is only used as an illustrative example, not any limitation on 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 film, PE / PP film, PP / PE / PP film, PE / PP / PE film, and non-silicone release film.

[0537] The present application also provides a composite electrode, which is prepared according to the composite electrode preparation method provided above.

[0538] In some embodiments, the first solid electrolyte membrane and the second solid electrolyte membrane have different compositions.

[0539] Furthermore, the temperature, heating time and / or pressure of the first shaping roller assembly and the second shaping roller assembly of each heating roller are different.

[0540] It is understood that the different compositions of the first and second solid electrolyte membranes can be understood as different material systems or structural compositions of the solid electrolyte membranes. This difference results in different composite processes for the first and second solid electrolyte membranes. The present application utilizes two composite processes, one before the other, to tailor different composite processes to the performance of the first and second solid electrolyte membranes with the positive electrode sheet.

[0541] Further preferably, the electrode plate includes a current collector and a first active material layer and a second active material layer respectively arranged on both sides of the current collector, wherein the first active material layer is bonded to the first solid electrolyte membrane and the second active material layer is bonded to the second solid electrolyte membrane; the first active material layer and the second active material layer are different.

[0542] It can be understood that the difference between the first active material layer and the second active material layer mentioned above means that the first active material layer and the second active material layer have macroscopic performance differences, and any factors in the active material layer that may cause macroscopic performance differences, such as composition, structure, surface density, etc., should be understood to be within the scope of protection of this application.

[0543] In some embodiments, the elastic roller is configured to wrap around and cover the elastic member outside the rigid roller. When the elastic roller rotates, the elastic member rotates with the elastic roller. Furthermore, when the shaping roller assembly rolls the first solid electrolyte membrane, the electrode sheet, and the second solid electrolyte membrane, the elastic member provides a cushioning effect, allowing the first and second solid electrolyte membranes to better cover both sides of the electrode sheet, while also improving the consistency of the transverse thickness of the electrode sheet after rolling.

[0544] It is understandable that during the production of electrode sheets, in order to ensure the smooth progress of the subsequent rolling process, the edges of the electrode sheets are usually thinned, and the existence of the thinned area of ​​the electrode sheets affects the fit between the solid electrolyte membrane and the electrode sheets; if the electrode sheets and the solid electrolyte membrane cannot form an effective composite in ...

Claims

1. A method for preparing a composite pole piece, comprising: The electrode sheet is conveyed by the electrode sheet unwinding mechanism so that the electrode sheet passes through the gap in the middle of the shaping roller assembly; The solid electrolyte membrane is conveyed by a solid electrolyte membrane unwinding mechanism located at the side of the electrode sheet unwinding mechanism, so that the solid electrolyte membrane passes through the gap between the shaping roller assembly and the electrode sheet; as well as Compounding the electrode sheet and the solid electrolyte membrane by a shaping roller assembly to obtain a composite electrode sheet; Wherein, an elastic member is arranged between the shaping roller assembly and the solid electrolyte membrane rolled onto the electrode plate.

2. The preparation method according to claim 1, further comprising: Heating the electrode plate, or the solid electrolyte membrane, or the electrode plate and the solid electrolyte membrane by a heating mechanism; The heating mechanism is located between the electrode sheet unwinding mechanism and the shaping roller assembly, and / or the heating mechanism is located inside the shaping roller assembly.

3. The preparation method according to claim 1, wherein The solid electrolyte membrane comprises a first solid electrolyte membrane and a second solid electrolyte membrane, and the first solid electrolyte membrane and the second solid electrolyte membrane are rolled and compounded on both sides of the electrode plate by the shaping roller assembly.

4. The preparation method according to claim 1, wherein The elastic member is a protective film or a rubber layer, and the protective film is transported through the gap between the shaping roller assembly and the solid electrolyte membrane; the rubber layer surrounds and covers the outside of the shaping roller assembly.

5. The preparation method according to claim 4, wherein: The adhesive layer is made of plastic, rubber or silicone; the protective film is made of polymer film or non-woven fabric.

6. The preparation method according to claim 1, wherein The shaping roller assembly includes a first shaping roller assembly and a second shaping roller assembly, and the elastic member is disposed between at least one of the first shaping roller assembly and the second shaping roller assembly and the solid electrolyte membrane rolled onto the electrode plate.

7. The preparation method according to claim 1, wherein The shaping roller assembly comprises a first shaping roller assembly and a second shaping roller assembly, and at least one of the first shaping roller assembly and the second shaping roller assembly and an elastic member form an elastic rolling assembly.

8. The preparation method according to claim 7, wherein: The elastic rolling assembly comprises an elastic roller, the elastic roller is used for contact rolling the solid electrolyte membrane, the elastic roller comprises a rigid roller and an elastic member, and the elastic member is coated on the outer side of the rigid roller.

9. The preparation method according to claim 8, wherein: The elastic rolling assembly includes a shaping steel roller and the elastic roller having a lower hardness than the shaping steel roller.

10. The preparation method according to claim 2, comprising: The electrode sheet is conveyed by the electrode sheet unwinding mechanism so that the electrode sheet passes through the gap between the heating mechanism and the shaping roller assembly; Preheating the electrode plate by the heating mechanism to obtain a preheating plate; and The preheating sheet and the solid electrolyte membrane are rolled and compounded by a shaping roller assembly to prepare a composite pole sheet.

11. The preparation method according to claim 2, wherein: The heating mechanism comprises a first heating mechanism and a second heating mechanism; The shaping roller assembly comprises a first shaping roller assembly and a second shaping roller assembly; The first heating mechanism is located between the electrode sheet unwinding mechanism and the first shaping roller assembly, and the second heating mechanism is located between the first shaping roller assembly and the second shaping roller assembly.

12. The preparation method according to claim 11, comprising: The electrode sheet is conveyed by the electrode sheet unwinding mechanism so that the electrode sheet passes through a first heating mechanism; The first solid electrolyte membrane is conveyed by a first solid electrolyte membrane unwinding mechanism located on one side of the electrode sheet unwinding mechanism, so that the first solid electrolyte membrane passes through a first heating mechanism; heating the electrode plate and the first solid electrolyte membrane by the first heating mechanism; Compounding the heated electrode sheet and the first solid electrolyte membrane by a first shaping roller assembly to obtain a composite membrane sheet; conveying a second solid electrolyte membrane through a second solid electrolyte membrane unwinding mechanism located on the other side of the electrode sheet unwinding mechanism, so that the second solid electrolyte membrane passes through a second heating mechanism; heating the composite membrane and the second solid electrolyte membrane by the second heating mechanism; and The heated composite membrane and the second solid electrolyte membrane are composited by a second shaping roller assembly to obtain a composite electrode.

13. The preparation method according to claim 2, wherein: The heating mechanism comprises a first heating mechanism and a second heating mechanism; the preparation method comprises: The electrode sheet is conveyed by the electrode sheet unwinding mechanism so that the electrode sheet passes through the gap between the first heating mechanism and the shaping roller assembly; The solid electrolyte membrane is conveyed by a solid electrolyte membrane unwinding mechanism located at the side of the electrode sheet unwinding mechanism, so that the solid electrolyte membrane passes through the second heating mechanism and the gap between the shaping roller assembly and the electrode sheet; Preheating the electrode plate by the first heating mechanism; preheating the solid electrolyte membrane by the second heating mechanism; The preheated electrode sheet and the solid electrolyte membrane are rolled and composited by a shaping roller assembly to prepare a composite electrode sheet.

14. The preparation method according to any one of claims 11 to 13, wherein: The first heating mechanism and the second heating mechanism are respectively selected from a heater and / or a heating roller assembly.

15. The preparation method according to claim 14, wherein: The heating roller assembly comprises one or more groups of heating rollers, and each group of heating rollers comprises at least one heating roller.

16. The preparation method according to claim 15, wherein: The heating temperatures of the plurality of heating rollers are the same or different, and / or the heating times of the plurality of heating rollers are the same or different.

17. The preparation method according to claim 16, wherein: The heating time of the plurality of heating rollers is 2 seconds or longer.

18. The preparation method according to any one of claims 11 to 13, wherein: The heating temperatures of the first heating mechanism and the second heating mechanism are the same or different, and / or the heating times of the first heating mechanism and the second heating mechanism are the same or different.

19. The preparation method according to claim 18, wherein: The heating time of the first heating mechanism and the second heating mechanism is 2 seconds or longer.

20. The preparation method according to claim 2, wherein: The heating mechanism is located between the electrode sheet unwinding mechanism and the shaping roller assembly, and is used to preheat the electrode sheet, the solid electrolyte membrane and the elastic member, wherein the elastic member is a protective film, and the protective film is transported through the gap between the shaping roller assembly and the solid electrolyte membrane.

21. The preparation method according to claim 2, comprising: The electrode sheet is conveyed by the electrode sheet unwinding mechanism so that the electrode sheet passes through the gap between the guide roller, the heating mechanism and the shaping roller assembly; The solid electrolyte membrane is conveyed by a solid electrolyte membrane unwinding mechanism located at the side of the electrode sheet unwinding mechanism, so that the solid electrolyte membrane passes through the guide roller, the heating mechanism and the gap between the shaping roller assembly and the electrode sheet; Controlling the electrode sheet and the solid electrolyte membrane to be laminated on the guide roller to prepare a laminated sheet; preheating the bonding sheet by the heating mechanism; and The preheated bonding sheets are rolled and laminated by the shaping roller assembly to prepare a composite electrode sheet.

22. The preparation method according to claim 2, comprising: Preheating the solid electrolyte membrane by the shaping roller assembly, wherein a heating mechanism is provided in the shaping roller assembly for preheating the solid electrolyte membrane; as well as The electrode sheet and the preheated solid electrolyte membrane are heated and rolled together by the shaping roller assembly to obtain a composite sheet.

23. The preparation method according to claim 22, comprising: The electrode sheet is conveyed by the electrode sheet unwinding mechanism so that the electrode sheet passes through the gap in the middle of the shaping roller assembly; The solid electrolyte membrane is conveyed by a solid electrolyte membrane unwinding mechanism located at the side of the electrode sheet unwinding mechanism, so that the solid electrolyte membrane reaches the shaping roller assembly for preheating and passes through the gap between the shaping roller assembly and the electrode sheet; as well as The electrode sheet and the preheated solid electrolyte membrane are heated and rolled together by a shaping roller assembly to obtain a composite electrode sheet; Wherein, during rolling, the temperature of the solid electrolyte membrane is higher than that of the electrode plate.

24. The preparation method according to claim 2, wherein: During rolling, the temperature of the solid electrolyte membrane is higher than that of the electrode plate.

25. The preparation method according to claim 2, further comprising: The electrode sheet, or the solid electrolyte membrane, or the electrode sheet and the solid electrolyte membrane are guided by a guide roller assembly to adjust the preheating time; The guide roller assembly is located between the electrode sheet unwinding mechanism and / or the solid electrolyte unwinding mechanism and the shaping roller assembly.

26. The preparation method according to claim 2, further comprising: Cooling the composite pole piece by a cooling roller; The cooling roller is located downstream of the sizing roller assembly.

27. The preparation method according to any one of claims 1 to 26, further comprising: The substrate covering the solid electrolyte membrane is separated from the composite pole piece.

28. The preparation method according to claim 27, further comprising: Between the shaping roller assembly and the composite pole piece winding mechanism, a substrate is received by a substrate winding mechanism; The substrate winding mechanism and the solid electrolyte membrane unwinding mechanism are located on the same side of the electrode plate unwinding mechanism.

29. The preparation method according to claim 28, wherein The shaping roller assembly includes a first shaping roller assembly and a second shaping roller assembly; the solid electrolyte membrane includes a first solid electrolyte membrane and a second solid electrolyte membrane, and the first solid electrolyte membrane and the second solid electrolyte membrane are respectively located on both sides of the electrode plate; Between the first shaping roller assembly and the second shaping roller assembly, a first substrate winding mechanism is used to receive a first substrate located on a side of the first solid electrolyte membrane away from the electrode sheet; Downstream of the second shaping roller assembly, a second substrate located on a side of the second solid electrolyte membrane away from the electrode plate is received by a second substrate winding mechanism.

30. The preparation method according to claim 1, wherein: The yield limit of the elastic member satisfies that: when the solid electrolyte membrane and the electrode plate pass through the gap in the middle of the shaping roller assembly, the solid electrolyte membrane and the electrode plate undergo plastic deformation, and the elastic member undergoes elastic deformation; The electrode plates include positive electrode plates and / or negative electrode plates.

31. The preparation method according to claim 30, wherein: The electrode plate has a structure that is thick in the middle and thin at both sides. During the rolling process, the force applied to the middle area of ​​the electrode plate is greater than that applied to the edge area.

32. The preparation method according to claim 31, wherein The electrode plate is obtained by dry preparation.

33. The preparation method according to claim 1, wherein The width of the elastic member is greater than or equal to the minimum value of the width of the solid electrolyte membrane or the electrode plate.

34. The preparation method according to claim 4, wherein: The elastic member is conveyed by a protective film unwinding mechanism; the protective film unwinding mechanism is located between the solid electrolyte membrane unwinding mechanism and the shaping roller assembly; and The elastic member is received by a protective film winding mechanism between the shaping roller assembly and the substrate winding mechanism.

35. The preparation method according to claim 10, wherein: The electrode plate is preheated several times, and the preheating temperature is gradually increased.

36. The preparation method according to claim 22, wherein: The shaping roller assembly comprises a first shaping roller assembly and a second shaping roller assembly, and a heating mechanism is disposed in both the first shaping roller assembly and the second shaping roller assembly.

37. The preparation method according to claim 7, wherein: The solid electrolyte membrane comprises a first solid electrolyte membrane and a second solid electrolyte membrane, wherein the first solid electrolyte membrane and the second solid electrolyte membrane are respectively located on both sides of the electrode plate; The first shaping roller assembly comprises a first shaping steel roller and a first elastic roller, wherein the first elastic roller is used for contact rolling and pressing the first solid electrolyte membrane; and / or The second shaping roller assembly includes a second shaping steel roller and a second elastic roller, and the second elastic roller is used for contact rolling the second solid electrolyte membrane.

38. A composite pole piece prepared by the preparation method according to any one of claims 1 to 37.

39. A lithium-ion battery, comprising a composite electrode prepared by the preparation method according to any one of claims 1 to 37.

40. A composite electrode preparation device, configured to perform the preparation method of any one of claims 1 to 37, the preparation device comprising: A shaping roller assembly, the shaping roller assembly comprising a first shaping roller and a second shaping roller; An electrode sheet unwinding mechanism, located upstream of the shaping roller assembly, for conveying the electrode sheet so that the electrode sheet passes through a gap between the first shaping roller and the second shaping roller; as well as A solid electrolyte membrane unwinding mechanism, located at the side of the electrode sheet unwinding mechanism, used for conveying the solid electrolyte membrane so that the solid electrolyte membrane passes through the gap between the first shaping roller and the second shaping roller; Wherein, an elastic member is arranged between the shaping roller assembly and the solid electrolyte membrane.

41. The preparation device according to claim 40, further comprising: A protective film unwinding mechanism, located between the solid electrolyte membrane unwinding mechanism and the shaping roller assembly, and used for conveying the elastic member; as well as A protective film winding mechanism, located between the shaping roller assembly and the substrate winding mechanism, and used for receiving the elastic member; The elastic member is a protective film.

42. The preparation device according to claim 40, wherein: The elastic member is a rubber layer, and the rubber layer surrounds and covers the outer side of the shaping roller assembly.

43. The preparation device according to any one of claims 40 to 42, further comprising: The heating mechanism is located between the electrode sheet unwinding mechanism and the shaping roller assembly, and is used to preheat the electrode sheet, or the solid electrolyte membrane, or the electrode sheet and the solid electrolyte membrane.

44. The preparation device according to claim 43, further comprising: The guide roller is located between the electrode sheet unwinding mechanism and the shaping roller assembly, and is used to guide the electrode sheet, or the solid electrolyte membrane, or the electrode sheet and the solid electrolyte membrane to adjust the preheating time.

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