Negative electrode plate for non-aqueous electrolyte secondary battery, and non-aqueous electrolyte secondary battery

Abstract

To provide a negative electrode plate for a non-aqueous electrolyte secondary battery, and a non-aqueous electrolyte secondary battery that can increase its energy density while preventing damage to active material particles.SOLUTION: A negative electrode plate for a non-aqueous electrolyte secondary battery according to the present invention has a negative electrode mixture layer including a negative electrode active material, a thickener, and a binder on both faces or one of the faces of a collector. The negative electrode active material is formed of carbon particles and carbon layers covering the surfaces of the carbon particles. The electrode density after pressing the negative electrode plate is 1.10 g / cm3 or more. An arithmetic average roughness (Ra) on a surface of the collector after removal of the negative electrode mixture layer of the negative electrode plate is 0.200 μm or more and 0.455 μm or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a negative electrode plate for a non-aqueous electrolyte secondary battery and a non-aqueous electrolyte secondary battery using the same. [Background technology]

[0002] Carbonaceous materials used as negative electrode materials for non-aqueous electrolyte secondary batteries have their negative electrode active material surface coated with amorphous carbon or the like for the purposes of resistance to electrolytes and suppression of volumetric changes during charge-discharge cycles, thereby achieving high electrolyte resistance and long cycle life characteristics.

[0003] On the other hand, in order to increase the energy density of non-aqueous electrolyte secondary batteries, particularly to improve the volumetric energy density, there is a demand for higher capacity active materials, thinner current collectors, and improved electrode density in negative electrode plates.

[0004] While improving electrode density is the easiest solution because it can be achieved without changing the material type, excessive pressing of the negative electrode plate not only compresses the active material layer, but also causes peeling of the active material layer and destruction of the active material particles, which can lead to deactivation of the active material and an increase in side reactions, resulting in a decrease in energy density and a decrease in charge-discharge cycle characteristics. Therefore, to improve electrode density, it is necessary to apply just the right amount of pressing to compress the active material layer.

[0005] For example, by using a current collector whose area increase rate when pressed falls within a predetermined range, electrode distortion due to the difference in ductility between the current collector and the composite layer during pressing is suppressed, thereby improving cycle life, etc. (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 3783503 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the method described in Patent Document 1 only improves the attained density of the composite layer, and is insufficient as a countermeasure against the deterioration of battery characteristics (such as reduced capacity and cycle characteristics) caused by damage to the active material particles due to excessive pressing (such as cracking of the particles and destruction of the surface coating layer).

[0008] The present invention has been made in view of the above, and an object of the present invention is to provide a negative electrode plate for a nonaqueous electrolyte secondary battery and a nonaqueous electrolyte secondary battery that can achieve a high energy density while suppressing damage to active material particles. [Means for solving the problem]

[0009] In order to solve the above problems, the present invention provides a negative electrode plate for a non-aqueous electrolyte secondary battery, which comprises a negative electrode mixture layer containing a negative electrode active material, a thickener, and a binder on both or either one of the surfaces of a current collector, wherein the negative electrode active material comprises carbon particles and a carbon layer covering the surfaces of the carbon particles, and the electrode density of the negative electrode plate after pressing is 1.10 g / cm. 3 The negative electrode plate is characterized in that the arithmetic mean roughness (Ra) of the surface of the current collector from which the negative electrode mixture layer has been removed is 0.200 μm or more and 0.455 μm or less.

[0010] The nonaqueous electrolyte secondary battery according to the present invention is characterized by comprising: the negative electrode plate for a nonaqueous electrolyte secondary battery according to the above invention; a positive electrode; a separator interposed between the negative electrode plate and the positive electrode; and a nonaqueous electrolyte solution. [Effects of the Invention]

[0011] According to the present invention, in a non-aqueous electrolyte secondary battery, it is possible to increase the energy density while suppressing damage to active material particles. [Brief explanation of the drawings]

[0012] [Figure 1]FIG. 1 is an exploded perspective view illustrating the configuration of a nonaqueous electrolyte secondary battery including a negative electrode plate for a nonaqueous electrolyte secondary battery according to one embodiment of the present invention. [Figure 2] FIG. 2 shows the charge curves at the time of the initial charge for Examples 1 to 3 and Comparative Examples 1 and 2, with the negative electrode potential on the vertical axis and the charge capacity on the horizontal axis. [Figure 3] FIG. 3 shows the change in the arithmetic mean roughness (horizontal axis) of the surface of the negative electrode current collectors of Examples 1 to 3 and Comparative Examples 1 and 2, with the charging efficiency shown on the first vertical axis and the ratio of the discharge capacity at the 200th cycle to the discharge capacity at the 1st cycle shown on the second vertical axis. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following description. Furthermore, various modifications and improvements can be made to the present embodiments, and such modifications and improvements can also be included in the present invention.

[0014] 1 shows a configuration example of a coin-type nonaqueous electrolyte secondary battery (coin cell) as an example of an embodiment, but the shape of the nonaqueous electrolyte secondary battery of the present invention is not particularly limited and may be flat, cylindrical, prismatic, laminated, etc. Furthermore, the exterior of the nonaqueous electrolyte secondary battery is not particularly limited either and known materials such as laminate film, aluminum, aluminum alloy, and stainless steel can be used.

[0015] (Embodiment) FIG. 1 is an exploded perspective view illustrating the configuration of a nonaqueous electrolyte secondary battery including a negative electrode plate for a nonaqueous electrolyte secondary battery according to one embodiment of the present invention.

[0016] The nonaqueous electrolyte secondary battery 10 includes a case 1, a leaf spring 2, a spacer 3, a counter electrode 4 (positive electrode plate), a separator 5, a negative electrode plate 6, a gasket 7, and a cap 8. The nonaqueous electrolyte secondary battery 10 is a coin-type nonaqueous electrolyte secondary battery that includes a negative electrode plate (negative electrode plate 6) for a nonaqueous electrolyte secondary battery that is configured using a negative electrode current collector and a negative electrode composite layer.

[0017] In the nonaqueous electrolyte secondary battery 10, the case 1 and the cap 8 are fixed together by caulking or the like, and the battery is filled with a nonaqueous electrolyte. The nonaqueous electrolyte secondary battery 10 is liquid-tightly sealed by the case 1, the gasket 7, and the cap 8. The spacer 3, the counter electrode 4, the separator 5, and the negative electrode plate 6 are biased toward the cap 8 by the leaf spring 2. This keeps the components in close contact with each other.

[0018] <Negative electrode> The negative electrode plate 6 comprises a current collector and a negative electrode composite layer formed on both or either one of the surfaces of the current collector. The negative electrode composite layer is formed from a negative electrode active material, a thickener, and a binder. The negative electrode plate 6 is obtained by pressing with a roll press at a predetermined linear pressure. The electrode density of the negative electrode plate 6 is adjusted only by the gap between the press rolls, with the linear pressure and press speed kept constant. The electrode density can also be adjusted by adjusting the gap between the press rolls and the press pressure of the press. In this application, "electrode density" refers to the density of the negative electrode composite layer excluding the current collector. The current collector is not particularly limited as long as it is an electrolytic copper foil, and known or commercially available ones can be used. The thickness of the current collector is not particularly limited, but is preferably 4 μm to 12 μm.

[0019] The electrode density of the negative electrode mixture layer after pressing was 1.10 g / cm 3 It is preferable that the electrode density after pressing is 1.10 g / cm or more. 3If the compression is less than 1.28 g / cm, the contact area between the negative electrode active material and the electrolyte increases due to insufficient compression of the composite layer, increasing the irreversible capacity due to side reactions. In addition, the contact between the negative electrode active material particles and between the negative electrode composite layer and the current collector is insufficient, resulting in reduced load characteristics and peel strength. In addition, the electrode density after pressing is 1.28 g / cm. 3 In these cases, excessive compression of the negative electrode mixture layer can cause damage to the negative electrode active material particles (particle cracks, destruction of the particle surface coating layer, etc.), which can lead to an increase in the amount of side reactions and a decrease in cell capacity. For this reason, the electrode density of the negative electrode mixture layer should be set to 1.10 g / cm. 3 More than 1.28g / cm 3 It is preferable that it is less than 10 ...

[0020] The arithmetic mean roughness (Ra) of the surface of the electrolytic copper foil current collector from which the negative electrode composite layer of the negative electrode plate has been removed is preferably 0.200 μm or more and 0.455 μm or less. If the arithmetic mean roughness Ra is less than 0.200 μm, the negative electrode composite layer is insufficiently compressed, resulting in a deterioration in the above-mentioned characteristics. If the arithmetic mean roughness Ra exceeds 0.455 μm, the negative electrode composite layer is excessively compressed, resulting in damage to the negative electrode active material particles (particle cracks, destruction of the particle surface coating layer, etc.), which increases the irreversible capacity and deteriorates the cycle characteristics.

[0021] [Surface roughness measurement] The surface roughness is measured on the surface of the current collector from which the active material layer of the negative electrode plate has been removed. In this case, the active material layer is removed by masking the periphery of the electrode observation surface and then immersing the electrode in ion-exchanged water or running water to prevent scratches on the observation surface. Observation of the current collector surface and measurement of the arithmetic mean roughness Ra are performed using a microscope after the active material layer has been removed and the current collector has been dried. The arithmetic mean roughness Ra is measured at three locations on each of the horizontal and vertical sections of the observation field in accordance with JIS B0601:2013, with a cutoff value of 0.8 mm.

[0022] (Negative electrode active material) The negative electrode active material is not particularly limited as long as it is capable of absorbing and releasing lithium. The negative electrode active material is composed of carbon particles and a carbon layer covering the carbon particle surface. Examples of carbon particles include pyrolytic carbon, cokes such as pitch coke, needle coke, and petroleum coke, natural graphite, artificial graphite, mesocarbon microbeads (MCMB), hard carbon, soft carbon, glassy carbon, sintered organic polymer compounds (carbonized by sintering phenolic resin, furan resin, etc.), carbon fiber, carbon black, and activated carbon. Among the carbon particles, artificial graphite having a carbon layer (hereinafter also referred to as an "amorphous carbon layer") covering the carbon particle surface is particularly preferred. The average particle diameter of the negative electrode active material is preferably 3 μm or more and 10 μm or less. If the average particle diameter is less than 3 μm, there are concerns about a decrease in the fluidity of the slurry due to an increase in the specific surface area and a decrease in the cell capacity due to an increase in the amount of side reactions. Furthermore, if the average particle diameter exceeds 10 μm, there is a concern that the volumetric energy density may decrease due to reduced packing and that the cell's output characteristics may decrease due to reduced intra-particle diffusion. The amorphous carbon layer is preferably formed so as to cover the entire surface of the negative electrode active material. The amorphous carbon layer is preferably formed as a continuous layer that covers the entire surface of the negative electrode active material. The thickness of this amorphous carbon layer is not particularly limited, but is preferably in the range of 10 nm to 200 nm, and more preferably in the range of 20 nm to 150 nm. This range facilitates the insertion and desorption of lithium ions and allows the specific surface area to be controlled to an appropriate value. The raw materials and manufacturing method of amorphous carbon are not particularly limited, but may be, for example, carbonized heavy oils such as coal-based or petroleum-based tar, pitch, and asphalt.

[0023] (thickener) The thickener is not particularly limited, and known or commercially available thickeners can be used, such as carboxymethyl cellulose (CMC).

[0024] (binder) The binder is not particularly limited, and known or commercially available binders can be used. Examples of binders include fluorine-based resins such as polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE), fluorine-based rubber, styrene butadiene rubber (SBR), carboxymethyl cellulose (CMC), core-shell binders, polyvinyl alcohol, and polyimide or polyamide-imide polyimide resins. The binder can be used as a single substance, or as a mixture or copolymer of two or more substances.

[0025] <Positive electrode> The positive electrode plate is composed of a current collector and a positive electrode mixture layer formed on at least one surface of the current collector. The positive electrode mixture layer is formed from an active material, a conductive additive, and a binder. The current collector is not particularly limited as long as it is a rolled aluminum foil, and known or commercially available current collectors can be used.

[0026] (Cathode active material) The positive electrode active material is not particularly limited as long as it is a lithium transition metal oxide, such as lithium cobalt oxide (LCO) or lithium iron phosphate (LFP), and known or commercially available materials can be used.

[0027] (Conductive additive) The conductive additive is not particularly limited, and known or commercially available ones can be used. Examples of the conductive additive include carbon black such as acetylene black and ketjen black, carbon nanotubes, carbon fiber, activated carbon, graphite, and other conductive carbons. The conductive additive can be used alone or as a mixture of two or more of these.

[0028] (binder) The binder is not particularly limited, and known or commercially available binders can be used. Examples of binders include fluorine-based resins such as polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE), fluorine-based rubber, styrene butadiene rubber (SBR), carboxymethyl cellulose (CMC), core-shell binders, polyvinyl alcohol, and polyimide or polyamide-imide polyimide resins. The binder can be used as a single substance, or as a mixture or copolymer of two or more substances. The positive electrode plate having the above structure is pressed with a roll press at a predetermined linear pressure to obtain a positive electrode plate. The density is adjusted only by the gap between the rolls, and the linear pressure and pressing speed are kept constant.

[0029] <Nonaqueous electrolyte> The non-aqueous electrolyte contains a non-aqueous solvent in which a lithium salt is dissolved. The lithium salt may be, for example, one or a mixture of two or more selected from the group consisting of LiBF4, LiPF6, Li(FSO2)2N, and Li(CF3SO2)2N. The nonaqueous solvent is not particularly limited, but examples thereof include one or a mixture of two or more solvents selected from the group consisting of dimethyl carbonate (DEC), diethyl carbonate (DEC), dipropyl carbonate (DPC), ethyl methyl carbonate (EMC), ethylene carbonate (EC), propylene carbonate (PC), methyl propionate, methyl acetate, methyl formate, methyl butyrate, dioxolane, 2-methyltetrahydrofuran, tetrahydrofuran, dimethoxyethane, γ-butyrolactone, acetonitrile, and benzonitrile. DMC, DEC, DPC, EMC, EC, and PC are particularly preferred. Among these, EC is preferred because it can form a good coating on the negative electrode active material. The nonaqueous electrolyte preferably further contains additives other than the lithium salts described above for the purpose of forming a high-quality coating on the surface of the negative electrode active material through reductive decomposition during charge and discharge. The additives are not particularly limited, but examples include vinylene carbonate, fluoroethylene carbonate, 1,3,2-dioxathiolane-2,2-dioxide (MMDS), 1,5,2,4-dioxadithiane-2,2,4,4-tetraoxide, tris(trimethylsilyl) phosphite, 1-propene-1,3-sultone, and Li2PO2F2. These additives may be used alone or in combination.

[0030] <Separator> The separator is interposed between the counter electrode and the negative electrode. Examples of the separator include a porous sheet made of polymer or fiber, or a nonwoven fabric separator. The separator may also be a porous substrate having a ceramic layer, which is a heat-resistant insulating layer, laminated thereon.

[0031] In the present embodiment described above, the negative electrode plate has a negative electrode active material composed of carbon particles and a carbon layer covering the surface of the carbon particles, and the electrode density after pressing of the negative electrode plate is 1.10 g / cm 3 The arithmetic mean roughness (Ra) of the surface of the current collector from which the negative electrode composite layer of the negative electrode plate has been removed is 0.200 μm or more and 0.455 μm or less. This negative electrode plate allows the active material layer to be compressed without destroying the negative electrode active material or the surface amorphous carbon layer, and side reactions with the electrolyte are suppressed, resulting in a negative electrode plate with good performance, with high charge / discharge efficiency during the initial charge / discharge and a high discharge capacity retention rate during charge / discharge cycles. According to this embodiment, by using this negative electrode plate in a nonaqueous electrolyte secondary battery, it is possible to achieve a high energy density while suppressing damage to the active material particles that would otherwise occur due to excessive pressing, for example. [Example]

[0032] EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited to the embodiments described in the Examples.

[0033] Example 1 A negative electrode slurry was prepared by dispersing 98% by mass of artificial graphite (average particle size 7 μm (D50)) with an amorphous carbon layer, 1% by mass of carboxymethyl cellulose (CMC), and 1% by mass of styrene butadiene rubber (SBR) in ion-exchanged water as a solvent. This negative electrode slurry was applied to both sides of a 10 μm-thick copper foil and dried, resulting in an electrode density of 1.19 g / cm. 3 The negative electrode plate was fabricated by pressing the plate into a shape similar to that shown in FIG. Next, in order to evaluate the electrochemical properties, a 2032-type coin-type lithium secondary battery (hereinafter abbreviated as coin-type cell) having the structure described below was fabricated and evaluated. A 300 μm-thick lithium metal foil was attached to the surface of a 100 μm-thick stainless steel foil current collector to form a counter electrode. A nonaqueous electrolyte was prepared by dissolving 1.3 mol / L of LiPF as a lithium salt in a mixed solvent of ethylene carbonate, ethyl methyl carbonate, and dimethyl carbonate in a volume ratio of 2:5:3. A coin-shaped cell was fabricated using the negative electrode plate, counter electrode, electrolyte, and a separator made of a microporous polyolefin membrane in an argon atmosphere with a dew point of −50° C. or lower.

[0034] Example 2 Electrode density after pressing is 1.24g / cm 3 A coin-type cell was fabricated in the same manner as in Example 1, except that the negative electrode plate was fabricated so that:

[0035] Example 3 Electrode density after pressing is 1.26g / cm 3 A coin-type cell was fabricated in the same manner as in Example 1, except that the negative electrode plate was fabricated so that:

[0036] (Comparative Example 1) Electrode density after pressing is 1.28g / cm 3 A coin-type cell was fabricated in the same manner as in Example 1, except that the negative electrode plate was fabricated so that:

[0037] (Comparative Example 2) Electrode density after pressing is 1.17g / cm 3 A coin-type cell was fabricated in the same manner as in Example 1, except that the negative electrode plate was fabricated so that:

[0038] <Surface roughness measurement> Surface roughness measurements were performed on the current collector surface after removing the active material layer from the negative electrode plate. The active material layer was removed by attaching the negative electrode plate to a smooth glass plate, masking all four sides, and exposing the exposed surface to running ion-exchanged water. The current collector surface of the obtained sample was observed under a microscope, and a three-dimensional image of a 2000 μm square area without scratches was taken. The arithmetic mean roughness Ra (in accordance with JIS B0601:2013) was measured with a cutoff value of 0.8 mm. The above measurement was carried out at three locations vertically and horizontally in the observation field, a total of six measurements, and the average value was taken as the arithmetic mean roughness of each sample.

[0039] <First charge / discharge> The current value in the initial charge / discharge of a coin-type cell with a lithium metal counter electrode is preferably in the range of 0.01 to 0.60 ItA, where 1.0 ItA is the current value at which the rated capacity C of the nonaqueous electrolyte secondary battery is fully discharged in 1 hour (h), and for example, 0.01 ItA is the current value at which the rated capacity is fully discharged in 100 hours (h). In particular, during charging, it is preferable to go through at least two steps, such as (1) C×1 / 100 to C×2 / 100 and (2) C×40 / 100 to C×60 / 100, and then charge until the negative electrode potential reaches 0.00 V. During discharging, there is no need to go through any particular steps, and it is preferable to discharge until the negative electrode potential reaches 1.50 V. Here, the current value for each step can be changed within the above range. In this example, the initial charge was performed in three stages: (1) 0.01 ItA (C × 2 / 100), (2) 0.60 ItA (C × 48 / 100), and (3) 0.60 ItA (C × 50 / 100) until the negative electrode potential reached 0.00 V. The initial discharge was performed in one stage at 0.20 ItA until the negative electrode potential reached 1.50 V.

[0040] <Charge / discharge cycle> The current value in the charge / discharge cycle is preferably in the range of 0.2 to 1.0 ItA. The range of the negative electrode potential is preferably 0.00 to 1.50 V, the same as in the initial charge / discharge. In this example, the electrochemical cell after the above-mentioned initial charge / discharge was subjected to 200 charge / discharge cycles at 0.50 ItA for both charge and discharge in a negative electrode potential range of 0.00 to 1.50 V.

[0041] Table 1 shows the electrode density and arithmetic mean roughness Ra of Examples 1 to 3 and Comparative Examples 1 and 2. [Table 1] As shown in Table 1, the surface roughness of the current collector increases with increasing electrode density, and it is clear that the stress caused by pressing is not limited to compressing the active material layer but also extends to the current collector.

[0042] Table 2 shows the initial charge capacity, initial discharge capacity, charge / discharge efficiency, and volumetric energy density for Examples 1 to 3 and Comparative Examples 1 and 2. The charge capacity-negative electrode potential curves at the time of the initial charge are shown in Figure 2. Figure 2 shows the charge curves at the time of the initial charge for Examples 1 to 3 and Comparative Examples 1 and 2, with the negative electrode potential on the vertical axis and the charge capacity on the horizontal axis. In Figure 2, curve L1 shows the charge curve for Example 1, curve L2 shows the charge curve for Example 2, curve L3 shows the charge curve for Example 3, curve L4 shows the charge curve for Comparative Example 1, and curve L5 shows the charge curve for Comparative Example 2. [Table 2] As shown in Table 2, there is a tendency for the charge / discharge efficiency to decrease in the order of Example 1, Example 2, Example 3, Comparative Example 2, and Comparative Example 1. Similarly, there is a tendency for the volumetric energy density to decrease in the order of Example 1, Example 2, Example 3, Comparative Example 1, and Comparative Example 2. Furthermore, as shown in FIG. 2, peaks due to side reactions become more pronounced in the order of Example 1, Example 2, Example 3, Comparative Example 2, and Comparative Example 1, which clearly shows that excessive pressing destroys the active material particles and the surface amorphous layer, causing side reactions.

[0043] Table 3 shows the discharge capacities at the first cycle, and the discharge capacities and capacity retention rates at the 200th cycle for Examples 1 to 3 and Comparative Examples 1 and 2. [Table 3] As shown in Table 3, the discharge capacity and retention rate decrease in the order of Example 1, Example 2, Comparative Example 2, Example 3, and Comparative Example 1. Considering the improvement in volumetric energy density due to electrode density, it is clear that Examples 1 to 3 are superior to Comparative Examples 1 and 2.

[0044] <Arithmetic mean roughness Ra for each parameter> The test results are summarized in Figure 3, based on the arithmetic mean roughness Ra. In Figure 3, the horizontal axis represents the charge efficiency when the arithmetic mean roughness of the surface of the negative electrode current collectors of Examples 1 to 3 and Comparative Examples 1 and 2 is changed, and the second vertical axis represents the ratio of the discharge capacity at the 200th cycle to the discharge capacity at the 1st cycle. In Figure 3, the broken line L 11 is the charging efficiency (Capability Relation / %), and the broken line L 12 indicates the discharge capacity at the 200th cycle (Capability Relation / %(200th / 1st)). As shown in FIG. 3, by pressing the electrodeposited copper foil current collector from which the negative electrode material layer has been removed so that the arithmetic mean roughness (Ra) of the surface is 0.200 μm or more and 0.455 μm or less (range R1 shown in FIG. 3), it is possible to compress the active material layer without destroying the negative electrode active material or the amorphous carbon layer on the surface. It is clear that a negative electrode with good characteristics and energy density can be obtained within the above range of arithmetic mean roughness (Ra). [Explanation of symbols]

[0045] 1 case 2 leaf springs 3 spacers 4 Positive electrode 5 Separator 6 negative electrode 7 Gasket 8 Cap 10 Non-aqueous electrolyte secondary batteries

Claims

1. A negative electrode plate for a non-aqueous electrolyte secondary battery, comprising a current collector and a negative electrode mixture layer on either or both surfaces thereof, the negative electrode mixture layer including a negative electrode active material, a thickener, and a binder, the negative electrode active material comprises carbon particles and a carbon layer covering the surfaces of the carbon particles, The electrode density of the negative electrode plate after pressing was 1.10 g / cm ３ That's all, The arithmetic mean roughness (Ra) of the surface of the current collector from which the negative electrode composite layer of the negative electrode plate has been removed is 0.200 μm or more and 0.455 μm or less. A negative electrode plate for a non-aqueous electrolyte secondary battery.

2. The electrode density is 1.10 g / cm ３ 1.28g / cm or more ３ is less than 2. The negative electrode plate for a non-aqueous electrolyte secondary battery according to claim 1.

3. The carbon particles are made of at least artificial graphite.

2. The negative electrode plate for a non-aqueous electrolyte secondary battery according to claim 1.

4. The carbon layer is an amorphous carbon layer.

2. The negative electrode plate for a non-aqueous electrolyte secondary battery according to claim 1.

5. The average particle size of the negative electrode active material is 3 μm or more and 10 μm or less.

2. The negative electrode plate for a non-aqueous electrolyte secondary battery according to claim 1.

6. The negative electrode plate for a non-aqueous electrolyte secondary battery according to any one of claims 1 to 5, A positive electrode and a separator interposed between the negative electrode plate and the positive electrode; a nonaqueous electrolyte; A non-aqueous electrolyte secondary battery comprising:

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