Method for manufacturing a negative electrode sheet for a non-aqueous secondary battery and method for manufacturing a non-aqueous secondary battery

Abstract

The present invention provides a method for manufacturing a negative electrode sheet for a non-aqueous secondary battery, which produces a low-resistance battery, and a method for manufacturing a non-aqueous secondary battery. [Solution] The negative electrode composite material constituting the negative electrode sheet of a non-aqueous secondary battery comprises a negative electrode active material, a negative electrode thickener, and a negative electrode binder, with CMC-Na (carboxymethylcellulose-sodium) polymer material used as the negative electrode thickener. The method for manufacturing the negative electrode sheet of a non-aqueous secondary battery includes a kneading step of producing a negative electrode composite paste by dispersing the negative electrode composite material in a solvent and kneading it, and a coating step of coating the negative electrode composite paste onto a negative electrode substrate constituting the negative electrode sheet, and includes a heating step of heating the negative electrode composite paste during the kneading step or between the kneading step and the coating step.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a negative electrode sheet of a non-aqueous secondary battery and a method for manufacturing a non-aqueous secondary battery.

Background Art

[0002] In the method for manufacturing an electrode for a lithium-ion battery described in Patent Document 1, carboxymethyl cellulose (CMC) is used as a binder for the active material paste. In the manufacturing method described in Patent Document 1, by adjusting the type of the binder and increasing the gaps between the molecules constituting the binder, the movement of lithium ions is not inhibited.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in the method for manufacturing an electrode for a lithium-ion battery described in Patent Document 1, since cellulose having a high molecular weight with a weight average molecular weight of 1,400,000 or more is used as a binder, the viscosity of the active material paste becomes high, and there is a risk that the workability during coating decreases.

Means for Solving the Problems

[0005] A method for manufacturing a negative electrode sheet for a non-aqueous secondary battery that solves the above problems is provided, wherein the negative electrode composite material constituting the negative electrode sheet for the non-aqueous secondary battery comprises a negative electrode active material, a negative electrode thickener, and a negative electrode binder, and a polymer material CMC-Na (carboxymethylcellulose-sodium) is used as the negative electrode thickener, and the method includes a kneading step of dispersing the negative electrode composite material in a solvent and kneading it to produce a negative electrode composite paste, and a coating step of coating the negative electrode composite paste onto a negative electrode substrate constituting the negative electrode sheet, and includes a heating step of heating the negative electrode composite paste during the kneading step or between the kneading step and the coating step.

[0006] According to the above configuration, a polymer material of CMC-Na is used as the negative electrode thickener in the negative electrode sheet, and the negative electrode mixture paste is heated during the kneading process, or between the kneading and coating processes. By heating the negative electrode mixture paste, the intermolecular distance of CMC-Na increases, and the voids in the CMC-Na polymer film increase, thereby improving the reaction between the negative electrode active material and the electrolyte in a non-aqueous secondary battery. Therefore, even when a polymer material of CMC-Na is used as the negative electrode thickener in the negative electrode sheet, a battery with low resistance can be manufactured.

[0007] Regarding the method for manufacturing the negative electrode sheet of the non-aqueous secondary battery described above, it is preferable to heat the negative electrode composite paste to 40°C or higher and 100°C or lower in the heating step. Regarding the method for manufacturing the negative electrode sheet of the above-mentioned non-aqueous secondary battery, it is preferable that the heating step is performed during the kneading step using the heated solvent.

[0008] Regarding the method for manufacturing the negative electrode sheet of the non-aqueous secondary battery described above, it is preferable that the heating step is performed by heating the negative electrode mixture paste using the kneading machine. Regarding the method for manufacturing the negative electrode sheet of the non-aqueous secondary battery described above, it is preferable that the heating step is performed before the coating step by heating the negative electrode mixture paste in a storage device that stores the negative electrode mixture paste after the kneading step.

[0009] A method for manufacturing a non-aqueous secondary battery that solves the above problems is a method for manufacturing a non-aqueous secondary battery having a positive electrode sheet, a negative electrode sheet, and a non-aqueous electrolyte, wherein the negative electrode composite material constituting the negative electrode sheet includes a negative electrode active material, a negative electrode thickener, and a negative electrode binder, and a polymer material of CMC-Na (carboxymethylcellulose-sodium) is used as the negative electrode thickener, and the method includes a kneading step of dispersing the negative electrode composite material in a solvent and kneading it to produce a negative electrode composite paste, and a coating step of coating the negative electrode composite paste onto a negative electrode substrate constituting the negative electrode sheet, and includes a heating step of heating the negative electrode composite paste during the kneading step or between the kneading step and the coating step.

[0010] According to the above method, a polymer material of CMC-Na is used as the negative electrode thickener in the negative electrode sheet, and the negative electrode mixture paste is heated during the kneading process or between the kneading and coating processes. By heating the negative electrode mixture paste, the intermolecular distance of CMC-Na increases, and the voids in the CMC-Na polymer film are increased, thereby improving the reaction between the negative electrode active material and the electrolyte in a non-aqueous secondary battery. Therefore, even when a polymer material of CMC-Na is used as the negative electrode thickener in the negative electrode sheet, a battery with low resistance can be manufactured. [Effects of the Invention]

[0011] According to the present invention, a low-resistance battery can be manufactured. [Brief explanation of the drawing]

[0012] [Figure 1] This is a perspective view showing the schematic configuration of the cell battery according to the first embodiment. [Figure 2] This is a diagram showing a portion of the electrode body of the same embodiment unfolded. [Figure 3] This is a flowchart showing the method for manufacturing the negative electrode sheet according to the same embodiment. [Figure 4] This figure shows the negative electrode material of the negative electrode sheet in the same embodiment. [Figure 5] This figure shows the negative electrode thickener contained in the negative electrode composite material of the negative electrode sheet in the same embodiment. [Figure 6]This figure shows a comparison of the low-temperature output of the non-aqueous secondary battery of the same embodiment. [Figure 7] This is a flowchart showing the method for manufacturing the negative electrode sheet according to the second embodiment. [Figure 8] This is a flowchart showing the method for manufacturing the negative electrode sheet according to the third embodiment. [Modes for carrying out the invention]

[0013] [First Embodiment] The first embodiment of the method for manufacturing the negative electrode sheet of a non-aqueous secondary battery and the method for manufacturing a non-aqueous secondary battery will be described below with reference to Figures 1 to 6. A lithium-ion secondary battery will be described as an example of a non-aqueous secondary battery.

[0014] [Lithium-ion rechargeable battery 10] As shown in Figure 1, the lithium-ion secondary battery 10 is a cell battery that, when combined with multiple other lithium-ion secondary batteries 10, is enclosed in a resin or metal case to form a battery pack. The battery pack is used in hybrid vehicles and electric vehicles.

[0015] The lithium-ion secondary battery 10 comprises a battery case 11 and a cover 12. The battery case 11 is rectangular in shape with an opening on its upper side. The cover 12 seals the opening of the battery case 11. The battery case 11 and the cover 12 are made of a metal such as aluminum or an aluminum alloy. The lithium-ion secondary battery 10 is formed as a sealed battery case by attaching the cover 12 to the battery case 11.

[0016] The lid body 12 is provided with two positive electrode external terminals 13A and a negative electrode external terminal 13B. The positive electrode external terminal 13A and the negative electrode external terminal 13B are used for charging and discharging electric power. Inside the battery case 11, an electrode body 20 is accommodated. The positive electrode current collecting part 20A, which is the end part on the positive electrode side of the electrode body 20, is electrically connected to the positive electrode external terminal 13A via the positive electrode current collecting member 14A. The negative electrode current collecting part 20B, which is the end part on the negative electrode side of the electrode body 20, is electrically connected to the negative electrode external terminal 13B via the negative electrode current collecting member 14B. Also, a non-aqueous electrolyte is injected into the battery case 11 through a liquid injection hole not shown in the figure. Note that the shapes of the positive electrode external terminal 13A and the negative electrode external terminal 13B are not limited to the shapes shown in FIG. 1 and may be arbitrary shapes.

[0017] [Electrode body 20] As shown in FIG. 2, the electrode body 20 is a flat wound body obtained by winding a laminate in which a long positive electrode sheet 21 and a negative electrode sheet 24 are laminated via a separator 27. The positive electrode sheet 21, the negative electrode sheet 24, and the separator 27 are laminated such that the longitudinal direction of each coincides with the longitudinal direction D1. Before winding, the laminate is laminated in the order of the positive electrode sheet 21, the separator 27, the negative electrode sheet 24, and the separator 27. The positive electrode sheet 21 and the negative electrode sheet 24 are electrode sheets.

[0018] [Positive electrode sheet 21] The positive electrode sheet 21 includes a positive electrode current collector 22 and a positive electrode composite layer 23. The positive electrode current collector 22 is a foil-shaped positive electrode base material formed in a long shape. The positive electrode composite layer 23 is provided on each of the two opposing surfaces of the positive electrode current collector 22. The positive electrode current collector 22 includes a positive electrode side non-coated part 22A where the positive electrode current collector 22 is exposed without the formation of the positive electrode composite layer 23 at one end in the width direction D2.

[0019] The positive electrode current collector 22 is made of a metal foil composed of aluminum or an alloy mainly composed of aluminum. The positive electrode current collector 22 functions as a current collector in the positive electrode. The positive electrode side non-coated part 22A provided in the positive electrode current collector 22 forms the positive electrode side current collecting part 20A with the opposing surfaces being pressed against each other in the state of the wound body.

[0020] The positive electrode composite layer 23 is a cured form of a liquid positive electrode composite paste. The positive electrode composite paste contains a positive electrode active material, a positive electrode solvent, a positive electrode conductive material, and a positive electrode binder. The positive electrode composite layer 23 is formed when the positive electrode composite paste dries and the positive electrode solvent vaporizes. Therefore, the positive electrode composite layer 23 contains a positive electrode active material, a positive electrode conductive material, and a positive electrode binder.

[0021] The positive electrode active material is a lithium-containing composite oxide capable of intercalating and releasing lithium ions, which are charge carriers in the lithium-ion secondary battery 10. The lithium-containing composite oxide is an oxide containing lithium and other metallic elements other than lithium. The other metallic elements other than lithium are, for example, at least one selected from the group consisting of nickel, cobalt, manganese, vanadium, magnesium, molybdenum, niobium, titanium, tungsten, aluminum, and iron contained as iron phosphate in the lithium-containing composite oxide.

[0022] For example, lithium-containing composite oxides include lithium cobaltate (LiCoO2), lithium nickelate (LiNiO2), and lithium manganate (LiMn2O4). Another example is lithium-containing composite oxide, a ternary lithium-containing composite oxide containing nickel, cobalt, and manganese, which is lithium nickel-cobalt-manganate (LiNiCoMnO2). Yet another example is lithium iron phosphate (LiFePO4).

[0023] The positive electrode solvent is an NMP (N-methyl-2-pyrrolidone) solution, which is an example of an organic solvent. Examples of positive electrode conductive materials include carbon black such as acetylene black and Ketjenblack, carbon fibers such as carbon nanotubes and carbon nanofibers, and graphite. The positive electrode binder is an example of a resin component contained in the positive electrode paste. Examples of positive electrode binders include polyvinylidene fluoride (PVDF), polyvinyl alcohol (PVA), and styrene-butadiene rubber (SBR).

[0024] The positive electrode sheet 21 may have an insulating layer at the boundary between the uncoated portion 22A on the positive electrode side and the positive electrode composite layer 23. The insulating layer contains an inorganic component having insulating properties and a resin component that functions as a binder. The inorganic component is at least one selected from the group consisting of powdered boehmite, titania, and alumina. The resin component is at least one selected from the group consisting of PVDF, PVA, and acrylic.

[0025] [Negative electrode sheet 24] The negative electrode sheet 24 comprises a negative electrode current collector 25 and a negative electrode composite layer 26. The negative electrode current collector 25 is a foil-shaped negative electrode substrate formed in an elongated shape. The negative electrode composite layer 26 is provided on each of two opposing surfaces of the negative electrode current collector 25. The negative electrode current collector 25 has a negative electrode side unpainted portion 25A at one end in the width direction D2, which is located opposite the positive electrode side unpainted portion 22A, where the negative electrode composite layer 26 is not formed and the negative electrode current collector 25 is exposed.

[0026] The negative electrode current collector 25 is made of metal foil composed of copper or an alloy mainly composed of copper. The negative electrode current collector 25 functions as a current collector at the negative electrode. In the wound state, the unpainted negative electrode side portion 25A has opposing surfaces pressed against each other to form the negative electrode side current collector portion 20B.

[0027] The negative electrode composite layer 26 is a cured body of a liquid negative electrode composite paste. The negative electrode composite paste contains a negative electrode active material, a negative electrode solvent, a negative electrode thickener, and a negative electrode binder. The negative electrode composite layer 26 is formed when the negative electrode composite paste dries and the negative electrode solvent vaporizes. Therefore, the negative electrode composite layer 26 contains the negative electrode active material, and further, as additives, a negative electrode thickener and a negative electrode binder. The negative electrode composite layer 26 may further contain additives such as a conductive material.

[0028] The negative electrode active material is a material capable of intercalating and releasing lithium ions. Examples of negative electrode active materials include carbon materials such as graphite, poorly graphitizable carbon, and easily graphitizable carbon. The negative electrode solvent is, for example, water. As a negative electrode thickener, a polymer material such as CMC-Na (carboxymethylcellulose-sodium) is used as a thickener containing a sodium salt. The negative electrode binder can be the same as that used for the positive electrode binder. As an example of a negative electrode binder, SBR (styrene-butadiene copolymer) can be used as a binder containing a sodium salt.

[0029] [Separator 27] The separator 27 prevents contact between the positive electrode sheet 21 and the negative electrode sheet 24, and holds the non-aqueous electrolyte between the positive electrode sheet 21 and the negative electrode sheet 24. When the electrode body 20 is immersed in the non-aqueous electrolyte, the non-aqueous electrolyte penetrates from the ends in the width direction D2 of the separator 27 toward the center.

[0030] The separator 27 is a nonwoven fabric made of polypropylene or the like. As the separator 27, for example, porous polymer membranes such as porous polyethylene membranes, porous polyolefin membranes, and porous polyvinyl chloride membranes, and ion-conductive polymer electrolyte membranes can be used.

[0031] [Nonaqueous electrolyte] A non-aqueous electrolyte is a composition containing a supporting salt in a non-aqueous solvent. As the non-aqueous solvent, one or more materials selected from the group consisting of propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate, etc., can be used. In this embodiment, ethylene carbonate is used as the non-aqueous solvent. As the supporting salt, one or more lithium compounds (lithium salts) selected from LiPF6, LiBF4, LiClO4, LiAsF6, LiCF3SO3, LiC4F9SO3, LiN(CF3SO2)2, LiC(CF3SO2)3, LiI, etc., can be used.

[0032] [Manufacturing method] Next, the manufacturing method of the lithium-ion secondary battery 10 will be described with reference to Figures 3 to 5. The manufacturing method of the lithium-ion secondary battery 10 involves winding up a laminate in which a positive electrode sheet 21 and a negative electrode sheet 24 are stacked with a separator 27 in between. The wound electrode body 20 is then placed in a battery case 11. Then, a non-aqueous electrolyte is injected into the battery case 11 containing the electrode body 20, and a lid 12 is attached to the battery case 11 to seal it.

[0033] The method for manufacturing an electrode sheet, which is part of the manufacturing method for a lithium-ion secondary battery 10, includes a kneading step, a coating step, and a heating step. This manufacturing method is performed on a negative electrode sheet 24, which is an electrode sheet.

[0034] [Mixing process] As shown in Figure 3, in the mixing process, the materials for the negative electrode mixture paste are put into the mixer 40, and the negative electrode mixture is dispersed in the solvent and mixed to produce the negative electrode mixture paste. The negative electrode mixture contains a negative electrode active material, a negative electrode thickener, and a negative electrode binder. Here, the negative electrode thickener is a polymer material of CMC-Na (carboxymethylcellulose-sodium). The negative electrode solvent is warm water, which is a heated solvent. Therefore, the heating process is carried out during the mixing process. It is desirable that this warm water has a temperature that heats the negative electrode mixture paste to 40°C or higher and 100°C or lower. Furthermore, it is desirable that the warm water has a temperature that heats the negative electrode mixture paste to 50°C or higher and 90°C or lower. Furthermore, it is desirable that the warm water has a temperature that heats the negative electrode mixture paste to 60°C or higher and 80°C or lower.

[0035] [Coating Process] In the coating process, a negative electrode mixture paste is applied to the negative electrode substrate that makes up the negative electrode sheet. The electrode sheet, with the electrode mixture paste applied to the electrode substrate, is then wound onto a roll core.

[0036] As shown in Figure 4, the negative electrode active material 31 contained in the negative electrode composite paste is covered with a negative electrode thickener 32. As shown in Figure 5, when the negative electrode composite paste is heated, the intermolecular distance of CMC-Na, which is the negative electrode thickener 32, increases, increasing the voids in the CMC-Na polymer film covering the negative electrode active material 31. This increases the reaction area and improves the reaction between the negative electrode active material 31 and the electrolyte. Therefore, as shown in Figure 6, when comparing a lithium-ion secondary battery 10 manufactured with a negative electrode composite paste using 50°C hot water as the solvent to a lithium-ion secondary battery 10 manufactured with a negative electrode composite paste using room temperature water as the solvent, the low-temperature output improved by 10%. It is also possible to adjust the viscosity of the negative electrode composite paste by heating it, thereby suppressing a decrease in peel strength.

[0037] [Effects of the First Embodiment] Next, the effects of the first embodiment will be described. (1-1) A polymer material of CMC-Na is used as the negative electrode thickener 32 of the negative electrode sheet 24, and the negative electrode mixture paste is heated during the kneading process. By heating the negative electrode mixture paste, the intermolecular distance of CMC-Na increases, and the voids in the CMC-Na polymer film increase, thereby improving the reaction between the negative electrode active material 31 and the electrolyte in the lithium-ion secondary battery 10. Thus, even when a polymer material of CMC-Na is used as the negative electrode thickener 32 of the negative electrode sheet 24, a battery with low resistance can be manufactured.

[0038] (1-2) By heating the negative electrode composite paste to a temperature higher than room temperature, the intermolecular distance of CMC-Na can be increased, thereby increasing the voids in the CMC-Na polymer film. (1-3) By simply using warm water, which is a heated solvent, the negative electrode mixture paste can be heated while being kneaded.

[0039] [Second Embodiment] A second embodiment of the method for manufacturing the negative electrode sheet of a non-aqueous secondary battery and the method for manufacturing a non-aqueous secondary battery will be described below with reference to Figure 7. The method for manufacturing the negative electrode sheet of a non-aqueous secondary battery and the method for manufacturing a non-aqueous secondary battery in this embodiment differs from the first embodiment in that the negative electrode mixture paste is heated. The differences from the first embodiment will be explained below.

[0040] [Mixing process] As shown in Figure 7, in the mixing process, the materials for the negative electrode composite paste are put into the mixer 50, and the negative electrode composite is dispersed in the solvent and mixed to produce the negative electrode composite paste. The negative electrode composite contains a negative electrode active material, a negative electrode thickener, and a negative electrode binder. Here, the negative electrode thickener is a polymer material of CMC-Na (carboxymethylcellulose-sodium). The negative electrode solvent is water at room temperature. The mixer 50 is equipped with a heating device for heating the negative electrode composite paste. Therefore, the heating process is performed during the mixing process. It is desirable that the heating device heats the negative electrode composite paste to between 40°C and 100°C. Furthermore, it is desirable that the heating device heats the negative electrode composite paste to between 50°C and 90°C. Furthermore, it is desirable that the heating device heats the negative electrode composite paste to between 60°C and 80°C.

[0041] [Effects of the second embodiment] Next, the effects of the second embodiment will be described. In addition to the effects of (1-1) and (1-2) of the first embodiment, the following effects are also achieved.

[0042] (2-1) The kneader 50 is equipped with a heating device, which allows the anode composite paste to be heated and kneaded while being heated. As a result, the intermolecular distance of CMC-Na increases, and the voids in the CMC-Na polymer film can be increased.

[0043] [Third Embodiment] A third embodiment of the method for manufacturing a negative electrode sheet and a non-aqueous secondary battery will be described below with reference to Figure 8. The method for manufacturing a negative electrode sheet and a non-aqueous secondary battery in this embodiment differs from the first embodiment in that the negative electrode composite paste is heated. The differences from the first embodiment will be explained below.

[0044] [Mixing process] As shown in Figure 8, in the mixing process, the materials for the negative electrode mixture paste are put into the mixer 50, and the negative electrode mixture is dispersed in the solvent and mixed to produce the negative electrode mixture paste. The negative electrode mixture contains a negative electrode active material, a negative electrode thickener, and a negative electrode binder. Here, the negative electrode thickener is a polymer material of CMC-Na (carboxymethylcellulose-sodium). The negative electrode solvent is water at room temperature.

[0045] The negative electrode mixture paste is stored in the storage device 60 until it is coated. The storage device 60 stores the negative electrode mixture paste while stirring it. The storage device 60 is equipped with a heating device for heating the negative electrode mixture paste. Therefore, a heating process is performed between the mixing process and the coating process. It is desirable that the heating device heats the negative electrode mixture paste to a temperature of 40°C to 100°C. Furthermore, it is desirable that the heating device heats the negative electrode mixture paste to a temperature of 50°C to 90°C. Furthermore, it is desirable that the heating device heats the negative electrode mixture paste to a temperature of 60°C to 80°C.

[0046] After mixing the negative electrode mixture paste, its viscosity is measured in the storage device 60. The storage device 60 then sets the heating temperature according to the viscosity. For example, if the viscosity of the mixed negative electrode mixture paste is higher than a predetermined value, it is assumed that the CMC-Na has not been finely ground, so the heating temperature is set higher. As a result, the viscosity of the negative electrode mixture paste decreases, and the intermolecular distance between CMC-Na molecules widens. On the other hand, if the viscosity of the mixed negative electrode mixture paste is lower than a predetermined value, it is assumed that the CMC-Na has been finely ground, so the heating temperature is set lower. As a result, further viscosity reduction is suppressed, and the gaps between CMC-Na molecules can be widened. Thus, it is desirable to adjust the viscosity of the mixed negative electrode mixture paste by heating it to a high temperature when its viscosity is higher than a predetermined value.

[0047] [Effects of the third embodiment] Next, the effects of the third embodiment will be described. In addition to the effects of (1-1) and (1-2) of the first embodiment, the following effects are also achieved.

[0048] (3-1) The storage device 60 heats the negative electrode mixture paste, allowing the negative electrode mixture paste to be heated while being stored. This increases the intermolecular distance between CMC-Na molecules and increases the voids in the CMC-Na polymer film.

[0049] [Other embodiments] Each of the above embodiments can be implemented with the following modifications. Each of the above embodiments and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0050] In the third embodiment described above, the viscosity of the anode mixture paste after kneading was measured, and the heating temperature was set according to that viscosity. However, the anode mixture paste may be heated at a predetermined temperature without measuring its viscosity after kneading.

[0051] The lithium-ion secondary battery 10 may be installed in automated transport machines, special vehicles for cargo handling, electric vehicles, hybrid vehicles, etc., as well as in computers and other electronic devices, or it may constitute a system other than those mentioned above. For example, it may be installed in mobile objects such as ships and aircraft, or it may be part of a power supply system that supplies electricity from a power plant to buildings and homes where the secondary battery is installed via a substation or the like. [Explanation of symbols]

[0052] 10…Lithium-ion rechargeable battery 11…Battery case 12... Lid 13A... Positive external terminal 13B…Negative external terminal 14A... Positive electrode current collector 14B... Negative electrode current collector 20...Electrode body 20A... Positive electrode current collector 20B... Negative electrode current collector 21…Positive electrode sheet 22...Positive electrode current collector 22A...Unpainted area on the positive electrode side 23…Positive electrode composite layer 24... Negative electrode sheet 25...Negative electrode current collector 25A...Unpainted area on the negative electrode side 26…Negative electrode composite material layer 27... Separator 31...Negative electrode active material 32...Negative electrode thickener 40… Mixing machine 50… Mixing machine 60…Storage device

Claims

1. The negative electrode composite material constituting the negative electrode sheet of a non-aqueous secondary battery includes a negative electrode active material, a negative electrode thickener, and a negative electrode binder. As the negative electrode thickener, a polymer material called CMC-Na (carboxymethylcellulose-sodium) is used. A kneading step is performed to prepare a negative electrode mixture paste by dispersing the negative electrode mixture in a solvent and kneading it. The process includes a coating step of applying the negative electrode composite paste to the negative electrode substrate constituting the negative electrode sheet, The mixing process, or the process between the mixing process and the coating process, includes a heating process for heating the negative electrode mixture paste. A method for manufacturing a negative electrode sheet for a non-aqueous secondary battery.

2. In the heating step, the negative electrode composite paste is heated to a temperature of 40°C to 100°C. A method for manufacturing a negative electrode sheet for a non-aqueous secondary battery according to claim 1.

3. The heating step is performed during the kneading step using the heated solvent. A method for manufacturing a negative electrode sheet for a non-aqueous secondary battery according to claim 1 or 2.

4. The heating step is performed by heating the negative electrode mixture paste using the kneading machine. A method for manufacturing a negative electrode sheet for a non-aqueous secondary battery according to claim 1 or 2.

5. The heating step is performed before the coating step by heating the negative electrode mixture paste in a storage device that stores the negative electrode mixture paste after the mixing step. A method for manufacturing a negative electrode sheet for a non-aqueous secondary battery according to claim 1 or 2.

6. A method for manufacturing a non-aqueous secondary battery having a positive electrode sheet, a negative electrode sheet, and a non-aqueous electrolyte, The negative electrode composite material constituting the negative electrode sheet includes a negative electrode active material, a negative electrode thickener, and a negative electrode binder. As the negative electrode thickener, a polymer material called CMC-Na (carboxymethylcellulose-sodium) is used. A kneading step is performed to prepare a negative electrode mixture paste by dispersing the negative electrode mixture in a solvent and kneading it. The process includes a coating step of applying the negative electrode composite paste to the negative electrode substrate constituting the negative electrode sheet, The mixing process, or the process between the mixing process and the coating process, includes a heating process for heating the negative electrode mixture paste. A method for manufacturing a non-aqueous secondary battery.

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