Electrode plate manufacturing method and device and electrode plate

Abstract

The invention relates to an electrode plate manufacturing method and device and an electrode plate. The method comprises the following steps: mixing a battery active material, a conductive agent and a thermoplastic polymer binder to obtain an electrode mixture; feeding the electrode mixture into a fluidized bed to enable the electrode mixture to enter a fluidized state; preheating the carbon-coated foil current collector, and feeding the preheated carbon-coated foil current collector into a fluidized bed; adhering the electrode mixture in a fluidized state to a carbon-coated foil current collector based on a fluidized bed to form an active material layer; and rolling the carbon-coated foil current collector on which the active material layer is formed based on the rolling line pressure and the rolling temperature to obtain the electrode plate. By adopting the method, the electrode mixture and the preheated carbon foil coated current collector can be fed into the fluidized bed, so that the electrode mixture entering the fluidized state in the fluidized bed can form the active material layer on the preheated carbon foil coated current collector to obtain the electrode plate, and the active material layer with relatively small thickness can be formed.

Description

Technical Field

[0001] The present application relates to the technical field of battery manufacturing, and in particular to an electrode sheet manufacturing method, device and electrode sheet. Background Art

[0002] Lithium-ion battery is a highly efficient electrical energy / chemical energy conversion device. The positive and negative electrodes are the core components of lithium-ion batteries. There are two manufacturing processes: wet and dry. Among them, the wet electrode manufacturing process refers to mixing the binder, active electrode components and solvent to prepare a slurry, then applying the slurry to the current collector, and forming an electrode membrane on the current collector after drying to remove the solvent; the dry electrode manufacturing process refers to directly dry mixing the binder, active electrode components and conductive agent, and then rolling the dry mixture into an electrode membrane layer and then compounding it with the current collector.

[0003] At present, the dry electrode manufacturing process is gaining more and more favor due to its advantages such as not using any solvents, small footprint of manufacturing equipment, simple manufacturing process flow, and high compaction density. However, the current conventional dry electrode manufacturing process usually forms an electrode membrane first and then compounds it with a current collector. Therefore, it is difficult to make the electrode membrane layer thinner than 50 microns. At present, the consumer side has put forward higher requirements for the fast charging and discharging rate of the battery. Obviously, if the electrode membrane layer cannot be made thin, then the battery will find it difficult to exert its high-rate charging and discharging performance, making it difficult for the battery to meet the needs of the consumer side. Summary of the invention

[0004] Based on this, it is necessary to provide an electrode sheet manufacturing method, device and electrode sheet that can form an active material layer with a smaller thickness in order to solve the above technical problems.

[0005] In a first aspect, the present application provides a method for manufacturing an electrode sheet, comprising:

[0006] Mixing a battery active material, a conductive agent and a thermoplastic polymer binder to obtain an electrode mixture;

[0007] The electrode mixture is fed into the fluidized bed so that the electrode mixture enters a fluidized state;

[0008] preheating the carbon-coated foil current collector and feeding the preheated carbon-coated foil current collector into the fluidized bed;

[0009] Based on the fluidized bed, the electrode mixture in the fluidized state is adhered to the carbon-coated foil current collector to form an active material layer;

[0010] The carbon foil current collector on which the active material layer is formed is roll-pressed based on the roll-pressing line pressure and the roll-pressing temperature to obtain an electrode sheet.

[0011] In a second aspect, the present application also provides an electrode sheet manufacturing device, comprising:

[0012] A mixing module, used to mix the battery active material, the conductive agent and the thermoplastic polymer binder to obtain an electrode mixture;

[0013] A fluidizing module, used for feeding the electrode mixture into a fluidized bed so that the electrode mixture enters a fluidized state;

[0014] A preheating module, used for preheating the carbon-coated foil current collector and sending the preheated carbon-coated foil current collector into the fluidized bed;

[0015] A forming module, used for making the electrode mixture in a fluidized state adhere to the carbon-coated foil current collector to form an active material layer based on a fluidized bed;

[0016] The rolling module is used to roll the carbon-coated foil current collector forming the active material layer based on the rolling line pressure and rolling temperature to obtain the electrode sheet.

[0017] In a third aspect, the present application further provides an electrode sheet, which is manufactured by using part or all of the steps described in any method of the first aspect of the embodiment of the present application.

[0018] The electrode sheet manufacturing method, device and electrode sheet are as follows: battery active materials, conductive agents and thermoplastic polymer binders are mixed to obtain an electrode mixture; the electrode mixture is sent into a fluidized bed so that the electrode mixture enters a fluidized state; the carbon-coated foil current collector is preheated and the preheated carbon-coated foil current collector is sent into the fluidized bed; the electrode mixture entering the fluidized state is adhered to the carbon-coated foil current collector based on the fluidized bed to form an active material layer; the carbon-coated foil current collector forming the active material layer is rolled based on the rolling line pressure and rolling temperature to obtain an electrode sheet. The electrode sheet manufacturing method provided in the embodiment of the present application no longer needs to form an electrode membrane first and then composite it with a current collector base foil. Instead, the electrode mixture and the preheated carbon-coated foil current collector are fed into a fluidized bed so that the electrode mixture that enters a fluidized state in the fluidized bed can adhere to the preheated carbon-coated foil current collector to form an active material layer, and then the carbon-coated foil current collector with the active material layer formed is rolled to obtain an electrode sheet, thereby being able to form an active material layer with a smaller thickness, so as to obtain an electrode sheet with more excellent high-rate charge and discharge performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments of the present application or related technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 A schematic diagram of a process for manufacturing an electrode sheet in one embodiment;

[0021] Figure 2 A diagram showing an application environment of an electrode sheet manufacturing method in one embodiment;

[0022] Figure 3 FIG. 4 is a structural block diagram of an electrode sheet manufacturing device in one embodiment. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0024] In an exemplary embodiment, Figure 1 As shown, a method for manufacturing an electrode sheet is provided, and the method is applied to an electrode sheet manufacturing system as an example for description, including the following steps 102 to 110. Among them:

[0025] Step 102: Mix the battery active material, the conductive agent and the thermoplastic polymer binder to obtain an electrode mixture.

[0026] Among them, battery active materials refer to materials that can participate in redox reactions to store and release charge during the electrochemical energy conversion process of the battery. Battery active materials usually have high electrochemical activity and can undergo reversible chemical reactions with ions in the electrolyte to achieve the conversion between electrical energy and chemical energy.

[0027] Battery active materials include positive electrode active materials and negative electrode active materials. The positive electrode active material is the side of the battery where the reduction reaction occurs. The positive electrode active material is used to release electrons during the charging process, and the positive electrode active material is used to accept electrons during the discharging process. The negative electrode active material is the side of the battery where the oxidation reaction occurs. The negative electrode active material is used to accept electrons during the charging process, and the negative electrode active material is used to release electrons during the discharging process. The type of positive electrode active material and the type of negative electrode active material usually depend on the type of battery to which they are to be applied.

[0028] Conductive agent refers to a material used to reduce the internal resistance of the electrode sheet to improve the charge and discharge efficiency and power density of the electrode sheet.

[0029] Thermoplastic polymer binders refer to polymer materials that can soften and flow when heated and harden again after cooling. Thermoplastic polymer binders play a key role in the electrode sheet manufacturing process. They can be used to bond battery active materials, conductive agents and carbon-coated foil current collectors together to form a stable electrode sheet structure.

[0030] In an exemplary embodiment, the positive electrode active material in the battery active material is composed of at least one of lithium nickel cobalt manganese oxide (NCM), lithium iron phosphate (LFP), lithium nickel cobalt aluminum oxide (NCA), lithium manganese oxide (LMO) and lithium cobalt oxide (LCO).

[0031] In an exemplary embodiment, the negative electrode active material in the battery active material is composed of at least one of natural graphite, synthetic graphite, hard carbon, soft carbon, activated carbon, silicon, silicon oxide, silicon carbon, tin, tin oxide and lithium titanate.

[0032] In an exemplary embodiment, the conductive agent is composed of at least one of conductive carbon black, carbon nanotubes, graphene, carbon fiber, acetylene black, and Ketjen black.

[0033] In an exemplary embodiment, the thermoplastic polymer binder includes one or more of polypropylene (PP), polyethylene (PE), polyvinylidene fluoride (PVDF), polyethylene oxide (PEO), and phenolic resin (PF), and does not include a fiberizable binder (PTFE).

[0034] Optionally, the thermoplastic polymer binder may further include at least one other thermoplastic resin when not including PTFE.

[0035] In this embodiment, the thermoplastic polymer binder includes one or more of PP, PE, PVDF, PEO, and PF, and the thermoplastic polymer binder does not include PTFE. Therefore, since it is no longer necessary to use PTFE used in the existing dry electrode sheet manufacturing process as a thermoplastic polymer binder, this avoids the undesirable situation that the thermoplastic polymer binder including PTFE reacts with lithium ions during the charge and discharge cycle in the negative electrode, and a part of the lithium ions are consumed, resulting in a decrease in the initial charge and discharge efficiency of the lithium battery. Furthermore, the use of the thermoplastic polymer binder provided in this embodiment can avoid the above-mentioned undesirable situation, that is, it can avoid the decrease in the initial charge and discharge efficiency of the lithium battery.

[0036] It is easy to understand that the quality of the electrode mixture directly affects the capacity, cycle life, charge and discharge rate and safety performance of the battery. Therefore, in the process of mixing the battery active material, conductive agent and thermoplastic polymer binder, the uniformity of the mixing should be ensured, that is, the obtained electrode mixture should have mixing uniformity.

[0037] In an exemplary embodiment, the battery active material, the conductive agent and the thermoplastic polymer binder are mixed to obtain an electrode mixture, including: mixing the battery active material, the conductive agent and the thermoplastic polymer binder based on a mixing device to obtain an electrode mixture.

[0038] The mixing device is a high-speed mixer with a high-speed rotor, and the high-speed rotor is one of a spiral ribbon rotor, a paddle rotor and a ploughshare rotor.

[0039] It should be noted that the mixing process of the battery active material, the conductive agent and the thermoplastic polymer binder is a dry mixing process.

[0040] Step 104: feeding the electrode mixture into a fluidized bed so that the electrode mixture enters a fluidized state.

[0041] Among them, the fluidized bed is a device that suspends solid particles (such as powders or small particles) under the action of a fluid (usually a gas, but can also be a liquid) so that the solid particles exhibit fluid-like properties, that is, the solid particles enter a fluidized state. In the fluidized bed, the solid particles exhibit a boiling-like motion under the action of the rising force of the fluid. The solid particles in this state have better mixing uniformity and heat and mass transfer efficiency.

[0042] Step 106, preheating the carbon-coated foil current collector, and sending the preheated carbon-coated foil current collector into the fluidized bed.

[0043] The carbon-coated foil current collector comprises a carbon-coated layer and a current collector base foil, and the current collector base foil is obtained by unwinding a metal foil coil.

[0044] Optionally, the carbon-coated foil current collector may be ready-made; the carbon-coated foil current collector may also be obtained by unwinding a metal foil coil to obtain a current collector base foil, and forming a carbon coating layer on the current collector base foil.

[0045] Metal foil coil refers to a material that is made by rolling metal (such as copper, aluminum, nickel or stainless steel) into thin sheets and then winding them into coils.

[0046] The current collector base foil refers to the flat sheet material obtained after unwinding the metal foil coil. Since the current collector base foil can provide good conductivity, chemical stability and mechanical support, the current collector base foil is mainly used as the base material of the current collector in the electrode sheet manufacturing process.

[0047] In an exemplary embodiment, the current collector base foil is composed of at least one of copper, aluminum, nickel, and stainless steel.

[0048] In an exemplary embodiment, the carbon coating layer is a single-sided carbon coating layer or a double-sided carbon coating layer on the current collector base foil.

[0049] Optionally, when the carbon-coated foil current collector only needs to achieve single-sided conductivity, the carbon-coated layer can be a single-sided carbon-coated layer on the current collector base foil; and when the carbon-coated foil current collector needs to achieve double-sided conductivity, the carbon-coated layer can be a double-sided carbon-coated layer on the current collector base foil.

[0050] In an exemplary embodiment, the carbon coating layer is continuously coated on the current collector base foil or intermittently coated on the current collector base foil.

[0051] Alternatively, when the carbon-coated foil current collector needs to have uniform conductivity, the carbon coating layer can be continuously coated on the current collector base foil; and in order to reduce material usage or create a specific electrochemical environment, the carbon coating layer can be intermittently coated on the current collector base foil.

[0052] Optionally, the carbon coating layer may be composed of at least one of carbon black, graphite, carbon fiber, and carbon nanotubes.

[0053] In this embodiment, a carbon-coated foil current collector is obtained by forming a carbon-coated layer on the current collector base foil. Thus, the carbon-coated layer can increase the binding force between the active material layer and the carbon-coated foil current collector, and at the same time can reduce the interface resistance between the active material layer and the carbon-coated foil current collector.

[0054] The preheated carbon-coated foil current collector can better exert its thermal viscosity than the preheated carbon-coated foil current collector, thereby enabling the electrode mixture to adhere to the carbon-coated foil current collector to form an active material layer.

[0055] Specifically, the electrode mixture is first fed into the fluidized bed so that the electrode mixture enters a fluidized state in the fluidized bed, and then the preheated carbon-coated foil current collector is fed into the fluidized bed so that the electrode mixture in the fluidized state is uniformly adhered to the carbon-coated layer of the preheated carbon-coated foil current collector that exerts thermal viscosity under the action of the fluidized bed to form an active material layer. Optionally, in the process of feeding the electrode mixture into the fluidized bed, the electrode mixture is continuously fed into the fluidized bed to ensure the uniformity and consistency of the active material layer formed.

[0056] Step 108 : Based on a fluidized bed, the electrode mixture in a fluidized state is made to adhere to the carbon-coated foil current collector to form an active material layer.

[0057] Among them, the active material layer refers to the material in the electrode sheet that can participate in the redox reaction during the charge and discharge process of the battery, thereby realizing the conversion between electrical energy and chemical energy.

[0058] Specifically, the fluidized bed includes a fluidized bed cavity and an air distribution plate located at the bottom of the fluidized bed. After the electrode mixture and the preheated carbon-coated foil current collector are fed into the fluidized bed, the hot air passes through the air distribution plate at the bottom of the fluidized bed and enters the fluidized bed cavity at a certain flow rate, so that the particles of the electrode mixture are blown up by the hot air and are in a suspended state. The electrode mixture particles in the suspended state are also in a flowing boiling state that is constantly rising and falling. When the preheated carbon-coated foil current collector travels in the fluidized bed, the preheated carbon-coated layer has thermal viscosity, so that the suspended electrode mixture particles will continue to adhere to the carbon-coated layer, and then a loose active material layer is formed on the carbon-coated foil current collector. Optionally, the inlet temperature of the hot air entering the fluidized bed cavity can be 100-160°C, so that the heat loss of the carbon-coated foil current collector in the fluidized bed can be supplemented.

[0059] Step 110 , rolling the carbon-coated foil current collector on which the active material layer is formed based on the rolling line pressure and rolling temperature to obtain an electrode sheet.

[0060] Among them, rolling is a process step in the electrode sheet manufacturing process, which is used to change the shape, size or structure of the electrode sheet.

[0061] Rolling line pressure refers to the pressure applied by two relatively rotating rollers to the carbon-coated foil current collector forming the active material layer during the rolling process. During the electrode sheet manufacturing process, the size of the rolling line pressure will affect the compaction density and uniformity of the electrode sheet, and thus affect the performance of the battery.

[0062] Rolling temperature refers to the temperature of the contact area between the roller and the carbon-coated foil current collector forming the active material layer during the rolling process. In the electrode sheet manufacturing process, the rolling temperature will affect the melting and resolidification process of the thermoplastic polymer binder, thereby affecting the structure and performance of the electrode sheet.

[0063] It is easy to understand that the rolling line pressure is negatively correlated with the thickness of the active material layer after rolling. Similarly, the rolling temperature is negatively correlated with the thickness of the active material layer after rolling. Based on this, optionally, in order to obtain an active material layer with a smaller thickness and a more ideal compaction density, a larger rolling line pressure can be used to roll the carbon-coated foil current collector forming the active material layer to obtain an electrode sheet. Similarly, a larger rolling temperature can be used to roll the carbon-coated foil current collector forming the active material layer to obtain an electrode sheet.

[0064] It is easy to understand that compared with the existing dry-process battery cell manufacturing method, the electrode sheet manufacturing method provided in the embodiment of the present application will further roll the carbon-coated foil current collector that forms the active material layer, so the thickness of the active material layer of the electrode sheet obtained in the embodiment of the present application will also be smaller.

[0065] In an exemplary embodiment, the roller pressure is 0.3-3 t / cm.

[0066] In an exemplary embodiment, the rolling temperature is 100-200°C.

[0067] In the present embodiment, based on the rolling line pressure and rolling temperature, the carbon-coated foil current collector forming the active material layer is rolled to obtain an electrode sheet. On the one hand, this is to melt the thermoplastic polymer binder again so that the melted thermoplastic polymer binder flows again to fill part of the pores between the active material particles in the active material layer, so that the active material particles can be tightly bonded together under the action of the thermoplastic polymer binder and the action of being squeezed, thereby forming an active material layer with higher density; on the other hand, under the dual action of pressure and temperature, the thermal viscosity of the carbon-coated layer on the carbon-coated foil current collector can be fully exerted, so that the active material layer can be more firmly adhered to the carbon-coated foil current collector, which can not only improve the bonding force between the active material layer and the carbon-coated foil current collector, but also reduce the interface resistance between the active material layer and the carbon-coated foil current collector, and thus, the battery performance of the battery used for the electrode sheet obtained based on this embodiment can be significantly improved.

[0068] It should be noted that since the electrode sheet manufacturing method provided in the embodiment of the present application does not use any solvent, the electrode sheet manufacturing method provided in the embodiment of the present application is a dry electrode sheet manufacturing method, and the electrode sheet obtained by the electrode sheet manufacturing method provided in the embodiment of the present application does not contain any solvent.

[0069] In the above-mentioned electrode sheet manufacturing method, battery active materials, conductive agents and thermoplastic polymer binders are mixed to obtain an electrode mixture; the electrode mixture is sent into a fluidized bed so that the electrode mixture enters a fluidized state; the carbon-coated foil current collector is preheated, and the preheated carbon-coated foil current collector is sent into the fluidized bed; the electrode mixture entering the fluidized state is adhered to the carbon-coated foil current collector based on the fluidized bed to form an active material layer; based on the rolling line pressure and rolling temperature, the carbon-coated foil current collector forming the active material layer is rolled to obtain an electrode sheet. The electrode sheet manufacturing method provided in the embodiment of the present application no longer needs to form an electrode membrane first and then composite it with a current collector base foil. Instead, the electrode mixture and the preheated carbon-coated foil current collector are fed into a fluidized bed so that the electrode mixture that enters a fluidized state in the fluidized bed can adhere to the preheated carbon-coated foil current collector to form an active material layer, and then the carbon-coated foil current collector with the active material layer formed is rolled to obtain an electrode sheet, thereby being able to form an active material layer with a smaller thickness, so as to obtain an electrode sheet with more excellent high-rate charge and discharge performance.

[0070] In an exemplary embodiment, the battery active material, the conductive agent and the thermoplastic polymer binder are mixed to obtain an electrode mixture, comprising:

[0071] The battery active material, the conductive agent and the thermoplastic polymer binder are mixed at a mixing temperature to obtain an electrode mixture.

[0072] The mixing temperature is the temperature at which the thermoplastic polymer binder softens.

[0073] In an exemplary embodiment, the battery active material, the conductive agent and the thermoplastic polymer binder are mixed at a mixing temperature to obtain an electrode mixture, including: mixing the battery active material, the conductive agent and the thermoplastic polymer binder at a mixing temperature based on a mixing device, and obtaining the electrode mixture after a mixing time.

[0074] Since the mixing temperature is the temperature at which the thermoplastic polymer binder softens, the mixing temperature is determined by the constituent materials of the thermoplastic polymer binder.

[0075] In an exemplary embodiment, the mixing time is 8-60 min.

[0076] In this embodiment, the battery active material, the conductive agent and the thermoplastic polymer binder are mixed at a mixing temperature to obtain an electrode mixture, and the mixing temperature is a temperature at which the thermoplastic polymer binder softens. Thus, the mixing temperature can cause the thermoplastic polymer binder to flow after melting to coat the surface of the battery active material to form a coating layer, thereby obtaining an electrode mixture with sufficient mixing uniformity.

[0077] In an exemplary embodiment, the thickness of the active material layer is 10-150 um.

[0078] In an exemplary embodiment, the thickness of the active material layer is 10-50 um.

[0079] In the present embodiment, since the active material layer is formed by continuously adhering the suspended electrode mixture to the carbon-coated foil current collector in a fluidized bed, the thickness of the active material layer is 10-150 um, thereby overcoming the technical limitation of the existing dry electrode sheet manufacturing process that requires first forming an electrode membrane and then compounding it with the current collector base foil, thereby overcoming the technical defect of the existing dry electrode sheet manufacturing method that makes it difficult to make the active material layer thinner than 50 um.

[0080] In an exemplary embodiment, the above-mentioned preheating of the carbon-coated foil current collector and feeding the preheated carbon-coated foil current collector into the fluidized bed includes:

[0081] The carbon-coated foil current collector is preheated at a preheating temperature of 100-200° C., and the preheated carbon-coated foil current collector is fed into a fluidized bed.

[0082] In this embodiment, the preheating temperature for preheating the carbon-coated foil current collector is 100-200°C, thereby improving the thermal viscosity of the preheated carbon-coated foil current collector, so that after the electrode mixture and the preheated carbon-coated foil current collector are fed into the fluidized bed, the electrode mixture entering the fluidized state can fully adhere to the carbon-coated foil current collector to form an active material layer.

[0083] In an exemplary embodiment, the above-mentioned method of making the electrode mixture in a fluidized state adhere to the carbon-coated foil current collector to form an active material layer based on a fluidized bed includes:

[0084] The travel time of the fluidized bed is determined based on the target thickness of the active material layer.

[0085] The fluidized bed is controlled based on the travel time, so that the electrode mixture entering the fluidized state adheres to the carbon-coated foil current collector to form an active material layer with a target thickness to obtain an electrode sheet.

[0086] Among them, the travel time is positively correlated with the target thickness.

[0087] The travel time of the fluidized bed refers to the time period from the electrode mixture entering the fluidized bed to leaving the fluidized bed. The travel time of the fluidized bed is affected by the length of the fluidized bed, the flow characteristics of the material, the flow rate of the fluidized bed, the physical properties of the material (such as density and particle size), and the operating conditions of the fluidized bed (for example, temperature and pressure).

[0088] Specifically, in the electrode sheet manufacturing process, the travel time of the fluidized bed affects the coating quality of the electrode mixture that enters the fluidized state and adheres to the carbon-coated foil current collector, thereby affecting the performance of the battery. The shorter the immersion time of the carbon-coated foil current collector in the fluidized bed, the thinner the active material layer. Conversely, the longer the immersion time in the fluidized bed, the thicker the active material layer. Therefore, the travel time of the fluidized bed is positively correlated with the target thickness.

[0089] Alternatively, the target thickness can be determined by the mixing temperature, preheating temperature, roller line pressure, roller temperature and travel time.

[0090] In this embodiment, the travel time of the fluidized bed is determined based on the target thickness of the active material layer, and then the fluidized bed is controlled based on the travel time, so that the electrode mixture entering the fluidized state adheres to the carbon-coated foil current collector to form an active material layer with a target thickness to obtain an electrode sheet. Thus, by controlling the travel time of the fluidized bed, it is possible to accurately control the immersion time of the carbon-coated foil current collector in the fluidized bed to obtain an electrode sheet with an active material layer of the target thickness that meets the requirements. Furthermore, it is possible to accurately adjust the target thickness of the active material layer by accurately controlling the immersion time, which can flexibly meet the requirements of battery design.

[0091] The electrode sheet manufacturing method provided in the embodiment of the present application can be applied to Figure 2 In the electrode sheet manufacturing system shown, the electrode sheet manufacturing system includes a preheating device 202, a fluidized bed 204 and a roller press 206, and hot air is continuously fed into the air distribution plate at the bottom of the fluidized bed 204. Specifically, battery active materials, conductive agents, thermoplastic polymer binders and carbon-coated foil current collectors are obtained, and then, the battery active materials, conductive agents and thermoplastic polymer binders are mixed in a high-speed mixer to obtain an electrode mixture; then, the electrode mixture is sent to a fluidized bed 204 so that the electrode mixture enters a fluidized state, and the carbon-coated foil current collector is sent to a preheating device 202, and the carbon-coated foil current collector is preheated by the preheating device 202, and the preheated carbon-coated foil current collector is sent to the fluidized bed 204, and the electrode mixture entering the fluidized state is adhered to the carbon-coated foil current collector in the fluidized bed 204 to form an active material layer; finally, in a roller press 206, the carbon-coated foil current collector forming the active material layer is rolled based on the rolling line pressure and the rolling temperature to obtain an electrode sheet.

[0092] The preheating device 202 may be an oven, a heating roller, an infrared heater, a hot air furnace or other devices or equipment that can preheat the carbon-coated foil current collector.

[0093] In this embodiment, the battery active material, the conductive agent and the thermoplastic polymer binder are first mixed and stirred at high speed and high temperature in a high-speed mixer to obtain an electrode mixture with a uniform mixture, and the carbon-coated foil current collector is preheated by a preheating device. The electrode mixture and the preheated carbon-coated foil current collector are then fed into a fluidized bed, where the electrode mixture in a fluidized state is adhered to the carbon-coated foil current collector which has exerted its thermal viscosity to form an active material layer. Finally, the carbon-coated foil current collector forming the active material layer is rolled in a roller press based on the rolling line pressure and the rolling temperature, thereby obtaining an electrode sheet having a smaller active material layer thickness and a more ideal compaction density.

[0094] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0095] Based on the same inventive concept, the embodiment of the present application also provides an electrode sheet manufacturing device for implementing the electrode sheet manufacturing method involved above. The implementation solution provided by the device to solve the problem is similar to the implementation solution recorded in the above method, so the specific limitations in one or more electrode sheet manufacturing device embodiments provided below can refer to the limitations of the electrode sheet manufacturing method above, and will not be repeated here.

[0096] In an exemplary embodiment, Figure 3 As shown, an electrode sheet manufacturing device is provided, including: a mixing module 302, a fluidizing module 304, a preheating module 306, a forming module 308 and a rolling module 310, wherein:

[0097] A mixing module 302 is used to mix the battery active material, the conductive agent and the thermoplastic polymer binder to obtain an electrode mixture;

[0098] A fluidizing module 304, used to feed the electrode mixture into a fluidized bed so that the electrode mixture enters a fluidized state;

[0099] A preheating module 306 is used to preheat the carbon-coated foil current collector and send the preheated carbon-coated foil current collector into the fluidized bed;

[0100] A forming module 308 is used to make the electrode mixture in a fluidized state adhere to the carbon-coated foil current collector to form an active material layer based on a fluidized bed;

[0101] The rolling module 310 is used to roll-press the carbon-coated foil current collector forming the active material layer based on the rolling line pressure and the rolling temperature to obtain an electrode sheet.

[0102] In an exemplary embodiment, the roller pressure is 0.3-3 t / cm.

[0103] In an exemplary embodiment, the rolling temperature is 100-200°C.

[0104] In an exemplary embodiment, the mixing module 302 is further used to mix the battery active material, the conductive agent and the thermoplastic polymer binder at a mixing temperature to obtain an electrode mixture; wherein the mixing temperature is a temperature at which the thermoplastic polymer binder softens.

[0105] In an exemplary embodiment, the thickness of the active material layer is 10-150 um.

[0106] In an exemplary embodiment, the thermoplastic polymer binder includes one or more of PP, PE, PVDF, PEO, and PF, and does not include PTFE.

[0107] In an exemplary embodiment, the preheating module 306 is further used to preheat the carbon-coated foil current collector at a preheating temperature of 100-200° C., and to feed the preheated carbon-coated foil current collector into the fluidized bed.

[0108] In an exemplary embodiment, the formation module 308 is also used to determine the travel time of the fluidized bed based on the target thickness of the active material layer; the fluidized bed is controlled based on the travel time, so that the electrode mixture entering the fluidized state adheres to the carbon-coated foil current collector to form an active material layer with a target thickness to obtain an electrode sheet; wherein the travel time is positively correlated with the target thickness.

[0109] Each module in the electrode sheet manufacturing device can be implemented in whole or in part by software, hardware, or a combination thereof. Each module can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in a computer device in the form of software, so that the processor can call and execute operations corresponding to each module.

[0110] In an exemplary embodiment, an electrode sheet is further provided. The electrode sheet is manufactured using the steps in the above method embodiments.

[0111] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0112] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A method for manufacturing an electrode sheet, characterized in that: The method comprises: Mixing a battery active material, a conductive agent and a thermoplastic polymer binder to obtain an electrode mixture; Feeding the electrode mixture into a fluidized bed so that the electrode mixture enters a fluidized state; Preheating the carbon-coated foil current collector and feeding the preheated carbon-coated foil current collector into a fluidized bed; Based on the fluidized bed, the electrode mixture in a fluidized state adheres to the carbon-coated foil current collector to form an active material layer; The carbon-coated foil current collector forming the active material layer is roll-pressed based on a roll-pressing line pressure and a roll-pressing temperature to obtain the electrode sheet.

2. The method according to claim 1, characterized in that The roller pressure is 0.3-3 t / cm.

3. The method according to claim 1, characterized in that The rolling temperature is 100-200°C.

4. The method according to claim 1, characterized in that: The battery active material, the conductive agent and the thermoplastic polymer binder are mixed to obtain an electrode mixture, comprising: Mixing the battery active material, the conductive agent and the thermoplastic polymer binder at a mixing temperature to obtain an electrode mixture; Wherein, the mixing temperature is the temperature at which the thermoplastic polymer binder softens.

5. The method according to claim 1, characterized in that The thickness of the active material layer is 10-150 um.

6. The method according to claim 1, characterized in that The thermoplastic polymer binder includes one or more of PP, PE, PVDF, PEO, and PF, but does not include PTFE.

7. The method according to claim 1, characterized in that The method of preheating the carbon-coated foil current collector and feeding the preheated carbon-coated foil current collector into a fluidized bed comprises: The carbon-coated foil current collector is preheated at a preheating temperature of 100-200° C., and the preheated carbon-coated foil current collector is fed into a fluidized bed.

8. The method according to claim 1, characterized in that The method of making the electrode mixture in a fluidized state adhere to the carbon-coated foil current collector to form an active material layer based on the fluidized bed comprises: determining a travel time of the fluidized bed based on a target thickness of the active material layer; Controlling the fluidized bed based on the travel time, so that the electrode mixture entering the fluidized state adheres to the carbon-coated foil current collector to form an active material layer with the target thickness to obtain an electrode sheet; The travel time is positively correlated with the target thickness.

9. An electrode sheet manufacturing device, characterized in that: The device comprises: A mixing module, used to mix the battery active material, the conductive agent and the thermoplastic polymer binder to obtain an electrode mixture; A fluidizing module, used for feeding the electrode mixture into a fluidized bed so that the electrode mixture enters a fluidized state; A preheating module, used for preheating the carbon-coated foil current collector and sending the preheated carbon-coated foil current collector into the fluidized bed; A forming module, used for making the electrode mixture in a fluidized state adhere to the carbon-coated foil current collector to form an active material layer based on the fluidized bed; The rolling module is used to roll the carbon-coated foil current collector forming the active material layer based on the rolling line pressure and the rolling temperature to obtain the electrode sheet.

10. An electrode sheet, characterized in that: The method is produced by any one of claims 1 to 8.

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