Method for producing slurry

Abstract

To provide a manufacturing method for a slurry that can efficiently produce slurry with reduced clumping.SOLUTION: A slurry for forming a protective layer of a non-aqueous electrolyte secondary battery includes an inorganic oxide filler, a binder, and a solvent. A slurry manufacturing method includes a step (S1) of dispersing an inorganic oxide filler in a solvent to obtain a dispersion, and a step (S2) of mixing and stirring the dispersion and the binder.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a slurry used for forming a protective layer of a non-aqueous electrolyte secondary battery.

Background Art

[0002] In non-aqueous electrolyte secondary batteries, it is known to form a protective layer on electrodes and the like. To form the protective layer, a paint obtained by mixing an inorganic oxide filler, a binder, and a solvent is used (for example, Patent Document 1 and the like).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] If there are lumps (aggregates) in the paint for forming the protective layer, defects may occur in the coating film and also in the protective layer. If time is spent in preparing the paint by mixing the components contained in the paint and stirring sufficiently, generation of lumps can be suppressed and a paint with uniformly dispersed filler can be obtained, but productivity will decrease. Therefore, it is required to efficiently prepare a paint with suppressed generation of lumps.

[0005] The present disclosure aims to provide a method for manufacturing a slurry for forming a protective layer of a non-aqueous electrolyte secondary battery, which can efficiently manufacture a slurry with suppressed generation of lumps.

Means for Solving the Problems

[0006] 〔1〕 A method for manufacturing a slurry for forming a protective layer of a non-aqueous electrolyte secondary battery, wherein the slurry contains an inorganic oxide filler, a binder, and a solvent, The manufacturing method is as follows: A step (S1) of dispersing the inorganic oxide filler in the solvent to obtain a dispersion; A method for manufacturing a slurry, comprising: a step (S2) of mixing and stirring the dispersion and the binder. 〔2〕 The step (S2) includes: A step (S2a) of obtaining a first mixed solution by mixing and stirring the dispersion and a part of all the binders contained in the slurry; The method for manufacturing a slurry according to 〔1〕, further comprising: a step (S2b) of mixing and stirring the first mixed solution with the remaining part or all of all the binders. 〔3〕 The method for manufacturing a slurry according to 〔2〕, wherein the step (S2b) is performed two or more times by mixing and stirring the first mixed solution with the remaining part of all the binders to obtain a second mixed solution. 〔4〕 The step (S2) is performed using a stirrer equipped with stirring blades, The method for manufacturing a slurry according to 〔2〕 or 〔3〕, wherein the rotation speed of the stirring blades in the step (S2) is 1500 rpm or more and 8000 rpm or less. 〔5〕 The inorganic oxide filler is one or more selected from the group consisting of alumina filler, magnesia filler, silica filler, zirconia filler, and titania filler. The method for manufacturing a slurry according to any one of 〔1〕 to 〔4〕. 〔6〕 The binder is a powder of a polymer compound. The method for manufacturing a slurry according to any one of 〔1〕 to 〔5〕. 〔7〕 The binder Agent is polyvinylidene fluoride (PVdF). The method for manufacturing a slurry according to any one of 〔1〕 to 〔6〕. 〔8〕 The viscosity of the slurry at a temperature of 10 to 40 °C is 500 mPa·s or more and 1500 mPa·s or less. The method for manufacturing a slurry according to any one of 〔1〕 to 〔7〕. 〔9〕 The solid content ratio of the slurry is 10% by weight or more and 40% by weight or less. The method for manufacturing a slurry according to any one of 〔1〕 to 〔8〕. 〔10〕The slurry manufacturing method according to any one of 〔1〕~〔9〕, wherein the slurry further contains a conductive agent. 〔11〕The slurry manufacturing method according to any one of 〔1〕~〔10〕, wherein the solvent is a non-aqueous solvent.

Advantages of the Invention

[0007] According to the present disclosure, a slurry with suppressed occurrence of pits can be efficiently manufactured.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0009] (Method for Manufacturing Slurry) FIG. 1 and FIG. 2 are flowcharts showing a method for manufacturing a slurry according to an embodiment of the present disclosure. The method for manufacturing a slurry of this embodiment is a method for manufacturing a slurry for forming a protective layer of a non-aqueous electrolyte secondary battery.

[0010] The protective layer can be provided on electrode bodies such as the positive electrode plate and the negative electrode plate included in the non-aqueous electrolyte secondary battery. For example, the protective layer may be formed so as to be adjacent to the positive electrode active material layer in a plan view of the positive electrode plate, may be formed so as to be adjacent to the negative electrode active material layer in a plan view of the negative electrode plate, and may be formed on the positive electrode active material layer and / or on the negative electrode active material layer so as to cover the surface of the positive electrode active material layer and / or the negative electrode active material layer. The protective layer provided on the positive electrode plate usually has a lower electric conductivity than the positive electrode current collector and the positive electrode active material layer. The protective layer provided on the negative electrode plate has a lower electric conductivity than the negative electrode current collector and the negative electrode active material layer. By providing the protective layer, it is possible to suppress the occurrence of an internal short circuit of the battery due to breakage of the separator or the like, and to improve the heat resistance of the positive electrode plate and the negative electrode plate.

[0011] The slurry contains an inorganic oxide filler, a binder, and a solvent. The slurry may further contain a conductive agent.

[0012] The inorganic oxide filler can be a metal oxide filler. Examples of the inorganic oxide filler include one or more selected from the group consisting of alumina (Al2O3) filler, magnesia (MgO) filler, silica (SiO2) filler, zirconia (ZrO2) filler, and titania (TiO2) filler.

[0013] The binder is preferably a polymer compound, more preferably a powder of a polymer compound. Examples of the polymer compound include one or more selected from the group consisting of polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), polyimide (PI), and polyamideimide (PAI). The polymer compound is preferably PVdF.

[0014] The solvent is preferably a non-aqueous solvent. Examples of the solvent include N-methyl-2-pyrrolidone (NMP).

[0015] Examples of the conductive agent include one or more selected from the group consisting of carbon black (such as acetylene black and ketjen black), graphite (such as flake graphite), carbon nanotubes, carbon nanohorns, graphene, and fullerenes.

[0016] The viscosity of the slurry at a temperature of 10 to 40 °C (25 ± 15 °C) is preferably 500 mPa·s or more and 1500 mPa·s or less, may be 700 mPa·s or more and 1400 mPa·s or less, or may be 800 mPa·s or more and 1300 mPa·s or less. The viscosity of the slurry is the value measured using a spiral viscometer at a temperature of 25 °C and a rotation speed of 40 rpm as described in the examples below. As a manufacturing method for manufacturing the slurry having the above viscosity, the manufacturing method of the slurry of the present embodiment is preferably used. Note that since the slurry of the present embodiment does not contain a positive electrode active material and a negative electrode active material, it is distinguished from the method for manufacturing a positive electrode slurry and a negative electrode slurry, and is also distinguished by the viscosity of the slurry. For example, the viscosity of the positive electrode slurry used to form the positive electrode active material layer is greater than the above viscosity of the slurry of the present embodiment.

[0017] The solid content ratio of the slurry is preferably 10% by weight or more and 40% by weight or less, more preferably 15% by weight or more and 30% by weight or less, and still more preferably 15% by weight or more and 25% by weight or less with respect to the total amount of the slurry. The solid content ratio of the slurry is the weight ratio of the solid content (components other than the solvent) to the total weight of the slurry. As a manufacturing method for manufacturing the slurry having the above solid content ratio, the manufacturing method of the slurry of the present embodiment is preferably used. Note that the solid content ratio of the positive electrode slurry used to form the positive electrode active material layer is greater than the above solid content ratio of the slurry of the present embodiment, and in this respect, it is also distinguished from the manufacturing method of the positive electrode slurry.

[0018] The content of the inorganic oxide filler contained in the slurry may be 40% by weight or more and 95% by weight or less, may be 50% by weight or more and 90% by weight or less, or may be 60% by weight or more and 85% by weight or less, based on the total amount of the solid content of the slurry. The content of the binder contained in the slurry may be 5% by weight or more and 50% by weight or less, or may be 10% by weight or more and 35% by weight or less, based on the total amount of the solid content of the slurry. The content of the conductive agent contained in the slurry may be 0% by weight or more and 10% by weight or less, or may be 0.05% by weight or more and 5% by weight or less, based on the total amount of the solid content of the slurry.

[0019] As shown in FIGS. 1 and 2, the method for producing the slurry of this embodiment includes a step (S1) of dispersing an inorganic oxide filler in a solvent to obtain a dispersion, and a step (S2) of mixing and stirring the dispersion and the binder. In the method for producing the slurry, the slurry is prepared through steps (S1) and (S2).

[0020] Since the binder is likely to become the nucleus of lumps (aggregates) generated in the slurry, a method of first mixing the binder and the solvent to prepare a binder solution and adding inorganic oxide particles to the binder solution to prepare the slurry is common. In contrast, in the method for producing the slurry of this embodiment, the binder is added to and mixed with the dispersion in which the inorganic oxide filler is dispersed in the solvent. The solvent has a lower viscosity compared to the binder solution. Therefore, in step (S1), it is easy to disperse the inorganic oxide filler in the solvent, and a dispersion with excellent dispersibility of the inorganic oxide filler can be efficiently obtained. Then, the slurry can be prepared in a shorter time while suppressing the formation of lumps in the slurry by a simple method of adding the binder to the dispersion and stirring (step (S2)). As described above, the method for producing the slurry of this embodiment can be particularly preferably used when the viscosity of the slurry is within the above-described range and / or when the solid content ratio of the slurry is within the above-described range.

[0021] In step (S1), for example, by adding an inorganic oxide filler to a solvent, a mixture of the solvent and the inorganic oxide filler can be obtained, and a dispersion can be obtained by stirring this mixture. Since the solvent has a low viscosity as described above, it is easy to disperse the inorganic oxide filler. In step (S1), a dispersion with a highly dispersed inorganic oxide filler can be obtained. The inorganic oxide filler may be added in its entirety at once to the solvent, or may be added in portions two or more times to the solvent. In step (S1), from the viewpoint of improving the productivity of the slurry, it is preferable to add the entire amount of the inorganic oxide filler to the solvent at once and stir. When adding the inorganic oxide filler in portions, the inorganic oxide filler may be added in portions while stirring the solvent or the mixture.

[0022] In step (S1), a stirrer equipped with stirring blades can be used to stir the solvent and the inorganic oxide filler. In step (S1) performed using a stirrer, the rotational speed of the stirring blades may be 1500 rpm or more and 6000 rpm or less, may be 2000 rpm or more and 5000 rpm or less, or may be 2500 rpm or more and 4000 rpm or less. When the rotational speed of the stirring blades is within the above range, the stirring time in step (S1) may be 10 minutes or more and 60 minutes or less, may be 15 minutes or more and 50 minutes or less, or may be 20 minutes or more and 40 minutes or less.

[0023] In step (S2), for example, by adding a binder to the dispersion and mixing and stirring the dispersion and the binder, a slurry can be obtained. In step (S2), the binder required for preparing the slurry may be added in its entirety at once to the dispersion and stirred, or may be added in portions two or more times while stirring the dispersion or the mixture.

[0024] For example, as shown in FIG. 2, step (S2) is a step (S2a) of obtaining a first mixture by mixing and stirring a part of all the binders contained in the dispersion and the slurry, and is a step (S2b) of mixing and stirring the first mixture with the remaining part or all of all the binders contained in the slurry. It may contain. The first mixture contains a dispersion liquid and a binder, but the content of the binder is smaller in the first mixture than in the slurry. The remainder of the total binder added in step (S2b) is the amount of binder obtained by subtracting the binder contained in the first mixture from the binder contained in the slurry.

[0025] When step (S2b) is a step of mixing and stirring the first mixture and all of the remainder of the binder contained in the slurry, a slurry can be obtained by step (S2b) (in FIG. 2, the solid line arrow proceeding from the preparation of the second mixture to the preparation of the slurry). Step (S2b) may perform the step of obtaining a second mixture two or more times by mixing and stirring the first mixture and a part of the remainder of the binder contained in the slurry (in FIG. 2, the dashed line arrow returning from the preparation of the second mixture to the addition of the binder). The second mixture contains the first mixture and a binder, and the content of the binder is larger in the second mixture than in the first mixture. In step (S2b), the step of obtaining the second mixture may be performed 3 or more times, 4 or more times, 5 or more times, and is usually 10 or less times.

[0026] By steps (S2a) and (S2b), a slurry can be obtained by cumulatively adding and stirring the binder contained in the slurry to the dispersion liquid in the total amount. By performing steps (S2a) and (S2b) in step (S2), since the binder can be added and stirred in small portions to the dispersion liquid and the first mixture, it is possible to suppress the occurrence of lumps in the slurry.

[0027] In step (S2), the dispersion liquid and the binder can be stirred using a stirrer equipped with stirring blades. In step (S2) performed using a stirrer, the rotational speed of the stirring blades may be, for example, 1500 rpm or more and 8000 rpm or less, 2000 rpm or more and 7000 rpm or less, or 3000 rpm or more and 6000 rpm or less.

[0028] When mixing the dispersion or the first mixture with the binder, it is preferable to heat the dispersion or the first mixture in order to promote the dissolution of the binder. The temperature during heating of the dispersion or the first mixture may be, for example, 35°C or higher and 60°C or lower, or may be 40°C or higher and 55°C or lower. The heating of the dispersion and the first mixture may adjust the liquid temperature to the above-mentioned range by heating with a heating device such as a heater. Alternatively, without using a heating device, the liquid temperature may be adjusted to the above-mentioned range by vigorously stirring the dispersion and the first mixture. When raising the liquid temperature by vigorous stirring, the rotation speed of the stirring blades in the stirrer can be, for example, within the above-mentioned range.

[0029] When performing step (S2a) and step (S2b) using a stirrer, the rotation speed and stirring time of the stirring blades may be the same or different. In step (S2b), when the step of obtaining the second mixture is performed two or more times, the rotation speed and stirring time of the stirring blades in each step may be the same or different.

[0030] When performing the stirring in step (S2a) and the step of obtaining the second mixture in step (S2b) n times (n represents an integer of 2 or more), in the stirring from the first time to the (n - 1)th time, the rotation speed of the stirring blades may each independently be 1500 rpm or higher and 6000 rpm or lower, may be 2000 rpm or higher and 5000 rpm or lower, may be 2500 rpm or higher and 4000 rpm or lower, and the stirring time may each independently be 1 minute or longer and 60 minutes or shorter, may be 3 minutes or longer and 30 minutes or shorter, may be 5 minutes or longer and 10 minutes or shorter.

[0031] When performing the step (S2b) only once, the stirring, and when performing the step of obtaining the second mixture in the step (S2b) n times (n represents an integer of 2 or more), in the nth stirring, the rotation speed of the stirring may be 1500 rpm or more and 6000 rpm or less, may be 2000 rpm or more and 5000 rpm or less, or may be 2500 rpm or more and 4000 rpm or less. The stirring time may be 30 minutes or more and 240 minutes or less, may be 60 minutes or more and 180 minutes or less, or may be 100 minutes or more and 150 minutes or less. When performing the step (S2b) only once, the stirring, and when performing the step of obtaining the second mixture in the step (S2b) n times (n represents an integer of 2 or more), the stirring time of the nth stirring may be longer than the stirring time of the stirring performed previously.

[0032] (Method for manufacturing a non-aqueous electrolyte secondary battery) The slurry obtained by the above-described slurry manufacturing method can be used in a method for manufacturing a non-aqueous electrolyte secondary battery. A non-aqueous electrolyte secondary battery usually includes an electrode body including a positive electrode plate, a negative electrode plate, and a separator, and an electrolyte, and the non-aqueous electrolyte secondary battery may further include a case for housing the electrode body and the electrolyte. The positive electrode plate has a positive electrode active material layer on a positive electrode current collector. The negative electrode plate has a negative electrode active material layer on a negative electrode current collector. The positive electrode plate and / or the negative electrode plate may have a protective layer. The electrode body has a structure in which a separator is sandwiched between the positive electrode active material layer of the positive electrode plate and the negative electrode active material layer of the negative electrode plate. The electrode body may be a wound electrode body or a laminated electrode body.

[0033] In the method for manufacturing a non-aqueous electrolyte secondary battery, for example, in the step of manufacturing a positive electrode plate and / or in the step of manufacturing a negative electrode plate, the above-described slurry can be used. The step of manufacturing a positive electrode plate can include a step of applying the slurry onto a positive electrode current collector or a positive electrode active material layer and drying it. The slurry may be applied onto the positive electrode current collector so as to be adjacent to the positive electrode active material layer formed on the positive electrode current collector in a plan view of the positive electrode plate. Alternatively, the slurry may be applied onto the positive electrode active material layer formed on the positive electrode current collector. The step of manufacturing a negative electrode plate can include a step of applying the slurry onto a negative electrode current collector or a negative electrode active material layer and drying it. The slurry may be applied onto the negative electrode current collector so as to be adjacent to the negative electrode active material layer formed on the negative electrode current collector in a plan view of the negative electrode plate. Alternatively, the slurry may be applied onto the negative electrode active material layer formed on the negative electrode current collector.

[0034] The positive electrode current collector is, for example, a metal foil formed using an aluminum material such as aluminum foil or an aluminum alloy. The positive electrode active material layer may include the positive electrode active material layer and further include one or both of a binder and a conductive assistant. Examples of the positive electrode active material include lithium transition metal oxides such as layered or spinel type (e.g., LiNiCoMnO2, LiNiO2, LiCoO2, LiFeO2, LiMn2O4, LiNi 0.5 Mn 1.5 O4, LiCrMnO4, LiFePO4, LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2). Examples of the binder include one or more selected from the group consisting of styrene-butadiene rubber (SBR), polyvinylidene fluoride (PVdF), and polytetrafluoroethylene (PTFE). Examples of the conductive assistant include carbon materials. Examples of the carbon materials include one or more selected from the group consisting of fibrous carbon, carbon black (acetylene black, ketjen black, etc.), coke, and activated carbon. Examples of the fibrous carbon include carbon nanotubes (CNT). The CNT may be a single-walled carbon nanotube (SWCNT) or a multi-walled carbon nanotube such as a double-walled carbon nanotube (DWCNT).

[0035] The negative electrode current collector is, for example, a metal foil made of a copper material such as copper and copper alloy. The negative electrode active material layer contains a negative electrode active material and may further contain one or both of a binder Agent and a conductive assistant. Examples of the negative electrode active material include carbon-based active materials containing carbon (C) atoms such as graphite (graphite); simple metals or metal oxides containing metal elements such as those selected from the group consisting of silicon (Si), tin (Sn), antimony (Sb), bismuth (Bi), titanium (Ti), and germanium (Ge). The binder Agent Examples include cellulose-based binders such as carboxymethyl cellulose (CMC). Agent Examples include styrene-butadiene rubber (SBR). Examples of the conductive assistant include carbon materials such as fibrous carbon, carbon black (for example, acetylene black, ketjen black), coke, and activated carbon. The fibrous carbon includes those described above.

Examples

[0036] Hereinafter, the present disclosure will be described more specifically by showing examples and comparative examples. [Preparation of Slurry Raw Materials] As raw materials for preparing the slurries of the examples and comparative examples, N-methyl-2-pyrrolidone (NMP) was prepared as a solvent, alumina (Al2O3) filler was prepared as an inorganic oxide filler, and polyvinylidene fluoride (PVdF) powder was prepared as a binder.

[0037] 〔Examples 1 to 4〕 The slurry of the example was prepared in the order shown in Figure 2 using a stirrer. As shown in step (S1) of Figure 2, the solvent and the inorganic oxide filler were stirred for 30 minutes at a rotational speed of 3000 rpm of the stirring blades to obtain a dispersion. As shown in step (S2a) of Figure 2, a binder was added to the dispersion, and the mixture was stirred for 5 minutes at a rotational speed of 3000 rpm of the stirring blades to obtain a first mixed solution. The operation of adding a binder to the first mixed solution and stirring it for 5 minutes at a rotational speed of 3000 rpm of the stirring blades was defined as one set, and this was continuously performed 4 sets (stirring from the first to the fourth times in step (S2b) shown in Figure 2). Then, a binder was further added and stirred for 120 minutes at the rotational speed shown in Table 1 (stirring at the last (fifth) time in step (S2b) shown in Figure 2), to obtain a slurry having the solid content ratio and temperature shown in Table 1. The temperature of the slurry is the temperature immediately after preparation. The total stirring time for all steps was 170 minutes.

[0038] [Comparative Example 1] The slurry of the comparative example was prepared in the order shown in Figure 3 using a stirrer. Figure 3 is a flowchart showing the manufacturing method of the slurry of the comparative example. As shown in Figure 3, while heating the solvent and the binder to 60 °C, the mixture was stirred for 60 minutes at a rotational speed of 3000 rpm of the stirring blades to obtain a binder solution. An inorganic oxide filler was added to the binder solution, and the mixture was stirred for 5 minutes at a rotational speed of 6000 rpm of the stirring blades to obtain a mixed solution (c1). The operation of adding an inorganic oxide filler to the mixed solution (c1) and stirring it for 5 minutes at a rotational speed of 6000 rpm was defined as one set, and this was continuously performed 4 sets (the arrow from the preparation of the mixed solution (c2) to the addition of the inorganic oxide filler in Figure 3). Then, an inorganic oxide filler was further added and stirred for 120 minutes at a rotational speed of 6000 rpm, to obtain a slurry having the solid content ratio shown in Table 1. The total stirring time for all steps was 200 minutes.

[0039] [Measurement of Viscosity of Slurry] A container filled with slurry was placed on the stage of a viscometer (spiral viscometer, manufactured by Malcolm Co., Ltd.). The rotational speed of the rotor of the viscometer was set to 40 rpm, and the rotor was immersed to a predetermined liquid level position of the slurry. After immersing the rotor in the slurry, the maximum value (peak value) was read from the values displayed on the viscometer, and this was taken as the viscosity [mPa·s]. After measuring the viscosity, the measurement temperature was measured with the viscometer and it was 25°C. The results are shown in Table 1.

[0040] [Evaluation of Dimples] A polyethylene terephthalate (PET) film was laid on a glass plate, and slurry was applied onto this PET film using an applicator with a coating thickness of 125 μm to form a coating film. The glass plate with the formed coating film was placed in a drying oven and dried at a temperature of 120°C for 10 minutes to form a protective layer, and the occurrence status of dimples was confirmed. Based on the occurrence status of dimples in Comparative Example 1, it was evaluated whether the size and number of dimples in each example were equivalent to the size and number of dimples in Comparative Example 1. The results are shown in Table 1.

[0041]

Table 1

Claims

1. A method for manufacturing a slurry for forming a protective layer of a non-aqueous electrolyte secondary battery, wherein the slurry contains an inorganic oxide filler, a binder, and a solvent, the binder is one or more selected from the group consisting of polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), polyimide (PI), and polyamideimide (PAI), the manufacturing method includes a step (S1) of dispersing the inorganic oxide filler in the solvent to obtain a dispersion, and a step (S2) of mixing and stirring the dispersion and the powdered binder, a method for manufacturing a slurry.

2. The step (S2) includes a step (S2a) of obtaining a first mixed solution by mixing and stirring the dispersion and a part of all the binders contained in the slurry, and a step (S2b) of mixing and stirring the first mixed solution and the remaining part or all of all the binders, the method for manufacturing a slurry according to Claim 1.

3. The step (S2b) performs, two or more times, a step of obtaining a second mixed solution by mixing and stirring the first mixed solution and the remaining part of all the binders, the method for manufacturing a slurry according to Claim 2.

4. The step (S2) is performed using a stirrer equipped with stirring blades, the rotation speed of the stirring blades in the step (S2) is 1500 rpm or more and 8000 rpm or less, the method for manufacturing a slurry according to Claim 2.

5. The inorganic oxide filler is one or more selected from the group consisting of alumina filler, magnesia filler, silica filler, zirconia filler, and titania filler, the method for manufacturing a slurry according to Claim 1.

6. The method for manufacturing the slurry according to claim 1, wherein the binder is polyvinylidene fluoride (PVdF).

7. The method for manufacturing the slurry according to claim 1, wherein the viscosity of the slurry at a temperature of 10 to 40 °C is 500 mPa·s or more and 1500 mPa·s or less.

8. The method for manufacturing the slurry according to claim 1, wherein the solid content ratio of the slurry is 10% by weight or more and 40% by weight or less.

9. The method for manufacturing the slurry according to claim 1, wherein the slurry further contains a conductive agent.

10. The method for manufacturing the slurry according to claim 1, wherein the solvent is a non-aqueous solvent.

11. A method for manufacturing a non-aqueous electrolyte secondary battery, including a step of manufacturing a positive electrode plate having a positive electrode active material layer on a positive electrode current collector, wherein the protective layer is formed so as to be adjacent to the positive electrode active material layer in a plan view of the positive electrode plate, the step of manufacturing the positive electrode plate includes forming the protective layer by applying a slurry on the positive electrode current collector so as to be adjacent to the positive electrode active material layer formed on the positive electrode current collector, The method for manufacturing a non-aqueous electrolyte secondary battery, wherein the slurry is a slurry manufactured by the method for manufacturing the slurry according to any one of claims 1 to 10.

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