JP-2026074493-A - Method for manufacturing secondary batteries or all-solid-state batteries

JP2026074493AJP 2026074493 AJP2026074493 AJP 2026074493AJP-2026074493-A

Abstract

[Problem] To prevent aggregation of active material particles for secondary batteries and carbon nanotubes (CNTs) and to form an electrode layer with a small amount of binder. [Solution] The CNTs are dispersed in a solvent that does not aggregate. The CNT dispersion is turned into liquid particles using an independent spraying device, etc., and is brought into contact with active material particles on a heated object to evaporate the solvent and form an electrode thin film layer in contact with the CNTs. Binder spray particles are then scattered and attached on top of this to form a thin film electrode layer in which at least some of the active material particles, conductive additives, and binder are bound together. [Selection Diagram] Figure 1

Inventors

松永正文

Assignees

エムテックスマート株式会社

Dates

Publication Date: 20260507
Application Date: 20241021

Claims (5)

A method for manufacturing a secondary battery or an all-solid-state battery, comprising applying a dispersion or slurry of electrode active material particles, electrolyte particles, a conductive additive, and a binder, selected from current collectors, electrode layers, electrolyte layers, and separators, in a solvent, to form an composite electrode layer, wherein the method comprises the steps of: preparing an active material dispersion or slurry with active material particles and at least a solvent; preparing a conductive additive dispersion with a conductive additive selected from carbon nanotubes, carbon nanofibers, graphene, and carbon particles and at least a solvent; and using binder fine particles, fibrous binder, binder solution, emulsion, and solvent. A method for manufacturing a secondary battery or an all-solid-state battery, characterized by forming an electrode layer by: a step of selecting and creating a liquid binder; a step of converting the active material particle dispersion or slurry, the conductive additive dispersion, and the liquid binder into liquid particles using an independent spray or particle generator to form a jet stream or pulsed jet stream; and a step of converging each of the jet streams or pulsed jet streams between the air or a heated object and impacting the object to coat it, or impacting heated objects sequentially or in any order to form a thin film layer, evaporating the solvent, and applying multiple layers of at least the same dispersion or slurry.
A method for manufacturing a secondary battery or all-solid-state battery according to claim 1, characterized by forming an electrode layer by: a step of converting a dispersion or slurry comprising the active material particles and at least a solvent, and a dispersion comprising carbon nanotubes and a solvent into an aggregate dispersion or slurry; a step of converting the aggregate dispersion or slurry into liquid particles using a spray or particle generator to form a jet stream or pulsed jet stream; a step of converting the liquid binder into liquid particles using a spray or particle generator to form a jet stream or pulsed jet stream; and a step of converging each of the jet streams or pulsed jet streams between the air and a heated object, causing them to collide with the object and be applied, or causing them to collide with heated objects sequentially or in any order to form a thin film layer, thereby evaporating the solvent, and applying multiple layers of at least the same dispersion or slurry.
A method for manufacturing a secondary battery or all-solid-state battery according to claim 1, comprising the steps of: adding an electrolyte particle dispersion or electrolyte particle slurry and converting it into liquid particles using a spray or particle generator to form a jet stream or pulsed jet stream; and merging each of the jet streams or pulsed jet streams between the air or a heated object and impacting the object to coat it, or impacting heated objects sequentially or in any order to form a thin film layer, evaporating the solvent, and applying at least multiple layers of the same dispersion or slurry.
A method for manufacturing a secondary battery or all-solid-state battery according to claim 1, characterized in that the conductive additive is a single-walled carbon nanotube, and the solid content of the binder is 3 percent or less of the total solid content weight of the electrode layer.
A method for manufacturing a secondary battery or an all-solid-state battery, comprising forming an electrode layer on a current collector by selecting electrode active material particles, a solid electrolyte, a conductive additive, and a binder, comprising the steps of: preparing a binder-free slurry by selecting active material particles or composite particles in which at least a portion of the active material particles is coated with a solid electrolyte, and solid electrolyte particles, and at least a solvent; preparing a binder-free conductive additive dispersion by at least carbon nanotubes and at least a solvent; and using binder fine particles, fibrous binder, binder solution, emulsion, and solvent. A method for manufacturing a secondary battery or an all-solid-state battery, characterized by the following steps: selecting and preparing a liquid binder; adding compressed gas to the slurry, dispersion, and liquid binder using an independent spray or particle generator to form liquid particles and then ejecting them as a jet stream or pulsed jet stream; mixing and adhering the jet stream or pulsed jet stream to a heated object before it reaches the object, or sequentially or randomly layering and applying each of the jet streams to the heated object; and forming an electrode layer in which at least a portion of the composite electrode layer is fixed with the binder.

Description

This invention relates to a method for manufacturing a secondary battery or an all-solid-state battery. The secondary batteries of this invention also include all-solid-state batteries and semi-solid-state batteries that have safety, high energy density, a high number of charge/discharge cycles, and high durability. With the increase in electric vehicles (EVs), lithium-ion battery (LIB) production is surging. Meanwhile, all-solid-state batteries, which use solid electrolytes such as sulfide or oxide-based electrolytes instead of solvent-based electrolytes, are gaining attention due to their safety and battery performance, including energy density. Furthermore, the manufacture and development of sodium, potassium, and zinc batteries, which use safe water-based electrolytes, are underway. In this invention, the ion conduction of the secondary battery can be selected from lithium, sodium, potassium, zinc, and others, and the type of battery is not limited. Materials for secondary battery electrodes and electrolyte formation can be selected from powders, fibers, and liquid materials. The active material particles for the positive electrode can be selected from ternary systems, iron phosphate, Prussian blue, manganese oxide, etc. The negative electrode active material can also be selected from graphite, silicon, etc., and the negative electrode can be a lithium plate or a zinc plate. The active material particles and conductive additives such as CNTs need to be dispersed in the desired state to form the electrode. These particles and fibers may be used to form electrodes by multiple means as independent dispersions or slurries, or they may be used as a dispersion or slurry composed of composite materials. The binder may be fine particles or fibers. For example, by fibrillating PTFE, the active material particles and composite materials with carbonanotubes (CNTs) can be fixedly bonded by pressing or heat pressing. Since the particles and fibers of the active material particles, conductive additives such as CNTs, and binders have poor affinity for solvents such as water, it is desirable to improve their water dispersibility by plasma treatment so that they can be dispersed in water or other solvents. Polymer-based dispersants remaining on the surface of the active material particles, CNTs, and other particles and fibers forming the electrode layer, which could hinder the conduction of ions and electrons, should be removed as much as possible. Therefore, the dispersibility of particles should be improved in a way that does not affect battery performance. Even if the weight ratio of particles is high in the dispersion or slurry of plasma-treated particles or fibers such as CNTs and a solvent such as water, and precipitation occurs, this problem can be solved by employing a method, for example, Japanese Patent Application Publication No. 2021-194581, invented by the present inventor, to rapidly move the slurry between, for example, two containers. This method stabilizes and maintains the viscosity of the slurry by applying a constant shear force, thus enabling a constant discharge rate per unit time. Therefore, the fibers can easily and accurately form networks to reinforce the electrode structure. The fiber binder can be composited with graphene or single-walled carbon nanotubes to create a conductive binder. As a result, the adhesion between interfaces, such as between the current collector and the electrode, or between the electrode and electrolyte particles in the case of all-solid-state batteries, can be improved and resistance can be reduced. By dispersing CNTs, particularly SWCNTs, with a dispersant or solvent, a dispersion with a solid weight percentage of 1% or less of SWCNTs can be formed that does not aggregate, allowing it to be applied to the target object. Furthermore, in addition to binders such as SBR, cellulose nanofibers can also be effectively used at the negative electrode. Nanoparticles, nanofibers, and carbon nanotubes (CNTs), especially single-walled carbon nanotubes (SWCNTs) with a diameter of around 2 nanometers, tended to aggregate when they contained high-viscosity cathode liquids or binder solutions, thus preventing them from realizing their full potential. More specifically, PVDF and PTFE are used as binders for electrode slurries, particularly for forming the positive electrode of secondary batteries, and NMP (n-methylpyrrolidone) and the like are used as solvents that can dissolve these binders. Generally, the positive electrode of a secondary battery uses a high-viscosity slurry with a weight-to-solids ratio of approximately 55 to 75%, consisting of active material particles, a binder, a conductive additive, and a solvent. In this case, achieving a uniform dispersion state of single-walled carbon nanotubes (WWNTs), which have a diameter of approximately 2 nanometers and a length of several tens of micrometers or more, was difficult. Furthermore, using high-boiling-point solvents such a