JP6667111B2 - Non-aqueous electrolyte secondary battery - Google Patents

Description

  The present invention relates to a non-aqueous electrolyte secondary battery.

  2. Description of the Related Art Non-aqueous electrolyte secondary batteries such as lithium ion secondary batteries (lithium secondary batteries) are lighter and have higher energy density than existing batteries. It is used as a drive power supply. The positive electrode of such a nonaqueous electrolyte secondary battery is configured by, for example, providing a positive electrode mixture layer on the surface of a positive electrode current collector that is a conductive foil.

In the above-described nonaqueous electrolyte secondary battery, in order to suppress various problems that occur when the battery is in an overcharged state (high voltage state), conventionally, a trilithium phosphate (Li ₃ PO ₃₎ Techniques for adding an inorganic phosphate compound such as ₄ ) have been proposed (for example, Patent Documents 1 to 3). Such an inorganic phosphate compound allows an acid (eg, hydrogen fluoride (HF)) generated by the decomposition of a non-aqueous electrolyte to be adsorbed on the particle surface when the battery is overcharged, thereby producing an overcharged battery. Heat generation and elution of metal elements can be suppressed.

JP 2014-103098 A JP 2015-103332 A Patent No. 3358478

  In the techniques described in Patent Documents 1 to 3 described above, the content of the inorganic phosphoric acid compound with respect to the positive electrode mixture layer is regulated in order to appropriately exert the effect of the inorganic phosphoric acid compound such as trilithium phosphate. . However, when trilithium phosphate is actually contained in the positive electrode mixture layer, the function of trilithium phosphate is reduced even though the content of trilithium phosphate is regulated as in the above-described conventional technology. Since a suitable effect may not be obtained due to variations, a technique capable of more appropriately exhibiting the function of trilithium phosphate has been desired.

In particular, a lithium ion secondary battery (a so-called 4V class battery) using a positive electrode active material having an operating potential of less than 4.3 V (vs. Li ^/ Li ⁺ ) has a property that a large amount of heat is generated when the battery is overcharged. Therefore, in the field of such a 4V-class battery, there has been a demand for the development of a technique capable of appropriately exerting the function of trilithium phosphate to appropriately suppress various problems caused by an overcharged state.

  The present invention has been made in view of the above points, and a main object of the present invention is to provide a nonaqueous electrolyte secondary battery in which trilithium phosphate is added to a positive electrode mixture layer, in which the addition of the trilithium phosphate is performed. An object of the present invention is to provide a non-aqueous electrolyte secondary battery capable of appropriately exhibiting the effects of the above, and suitably suppressing various problems caused by an overcharged state.

  In order to achieve the above object, the present invention provides a nonaqueous electrolyte secondary battery having the following configuration.

The nonaqueous electrolyte secondary battery disclosed herein has a positive electrode in which a positive electrode mixture layer is formed on a positive electrode current collector, and a negative electrode in which a negative electrode mixture layer is formed on a negative electrode current collector, A non-aqueous electrolyte secondary battery having a fluorine-containing lithium compound as a supporting salt, wherein the positive electrode mixture layer contains at least a positive electrode active material and trilithium phosphate particles. ing.
In the nonaqueous electrolyte secondary battery disclosed herein, the content of trilithium phosphate particles is 0.88 wt% when the solid content of the positive electrode mixture layer excluding trilithium phosphate particles is 100 wt%. a ～8.8Wt%, and a specific surface area of tricalcium phosphate lithium particles is 0.9m ² /g~20.3m ² / g.

  In order to solve the above-mentioned problems, the present inventor first conducted repeated experiments and studies on an appropriate content of trilithium phosphate with respect to the positive electrode mixture layer. Found that when the solid content of the positive electrode mixture layer excluding the trilithium phosphate was 100 wt%, the content was 0.88 wt% to 8.8 wt%. Specifically, when the content is less than 0.88 wt%, the content of trilithium phosphate is too small to exert an appropriate effect, while when the content exceeds 8.8 wt%, the viscosity of the positive electrode mixture is increased. It was confirmed by experiments that the ratio of the positive electrode mixture became too high, which made it difficult to apply the positive electrode mixture to the positive electrode current collector, resulting in a problem of reduced productivity.

Next, the present inventor, in order to prevent the occurrence of variations in the function of trilithium phosphate particles, despite the same content of trilithium phosphate particles with respect to the positive electrode mixture layer, the content other than the content The authors continued to study factors affecting the function of trilithium phosphate and focused on the specific surface area of trilithium phosphate particles.
Specifically, the present inventor pays attention to the effect of trilithium phosphate reacting with an acid (eg, hydrogen fluoride (HF)) generated by decomposition of a non-aqueous electrolyte, and appropriately causes such an effect. To this end, it was considered necessary to define the specific surface area of the trilithium phosphate particles in an appropriate range.
An experiment was conducted based on such considerations. As a result, when the specific surface area of the trilithium phosphate particles was increased, the effect of suppressing various problems in the overcharged state was increased, but the reaction resistance of the fabricated battery was increased. I got the knowledge to do it.
Further, as a result of further experiments based on this finding, the content of trilithium phosphate particles was set to 0.88 wt% to 8% when the solid content of the positive electrode mixture layer excluding the trilithium phosphate particles was 100 wt%. with in the range of .8wt%, by a specific surface area of tricalcium phosphate lithium particles in the range of 0.9m ² /g~20.3m ² / g, the effect of addition of trisodium phosphate lithium particles The present inventors have found that they can exert their effects properly and can suppress an increase in reaction resistance, and have completed the present invention.

FIG. 1 is a perspective view schematically showing an outer shape of a lithium ion secondary battery according to one embodiment of the present invention. It is a perspective view showing typically the electrode object of the lithium ion secondary battery concerning one embodiment of the present invention. 9 is a graph showing the results of an evaluation test in Experiment A. 9 is a graph showing the results of an evaluation test in Experiment B.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following drawings, members / parts having the same function are denoted by the same reference numerals. The dimensional relationships (length, width, thickness, etc.) in each drawing do not reflect actual dimensional relationships. In addition, matters other than matters specifically mentioned in the present specification and necessary for practicing the present invention (for example, the composition of the negative electrode and general techniques related to the construction of a nonaqueous electrolyte secondary battery) are as follows. It can be understood as a design matter of a person skilled in the art based on the prior art in the field.

1. Lithium ion secondary battery Hereinafter, a lithium ion secondary battery will be described as an example of the nonaqueous electrolyte secondary battery disclosed herein. FIG. 1 is a perspective view schematically illustrating the outer shape of the lithium ion secondary battery according to the present embodiment, and FIG. 2 is a perspective view schematically illustrating the electrode body of the lithium ion secondary battery according to the present embodiment. . This lithium ion secondary battery 100 is configured by housing an electrode body 80 shown in FIG. 2 in a rectangular battery case 50 shown in FIG.

(1) Battery Case The battery case 50 includes a flat case main body 52 having an open upper end, and a lid 54 closing an opening at the upper end. The lid 54 is provided with a positive electrode terminal 70 and a negative electrode terminal 72. Although not shown, the positive electrode terminal 70 is electrically connected to the positive electrode 10 of the electrode body 80 housed in the battery case 50, and the negative electrode terminal 72 is electrically connected to the negative electrode 20.

(2) Electrode Body Next, the electrode body 80 housed inside the battery case 50 will be described. As shown in FIG. 2, the electrode body 80 in the present embodiment is a wound electrode body manufactured by stacking and winding a long sheet-shaped positive electrode 10 and a long sheet-shaped negative electrode 20 together with a long sheet-shaped separator 40. It is. The electrode body used in the non-aqueous electrolyte secondary battery disclosed herein is not limited to a wound electrode body as shown in FIG. 2, for example, a plurality of positive electrodes and negative electrodes interposed with a separator interposed therebetween. It may be a laminated electrode body alternately laminated.

(A) Positive Electrode In the positive electrode 10 in FIG. 2, a positive electrode mixture layer 14 containing a positive electrode active material as a main component is formed on both surfaces of a long sheet-shaped positive electrode current collector 12. On one side edge of the positive electrode 10 in the width direction, a positive electrode mixture layer non-forming portion 16 on which the positive electrode mixture layer 14 is not applied is formed. Are electrically connected to the positive electrode terminal 70 (see FIG. 1).

  The positive electrode mixture layer 14 in the present embodiment includes a paste-like precursor (positive electrode mixture) obtained by dispersing a positive electrode active material, trilithium phosphate particles, and other additives in a dispersion medium. After applying to both surfaces of the positive electrode 12, the positive electrode mixture is dried to form the positive electrode mixture. The detailed composition of the positive electrode mixture layer 14 will be described later in detail.

(B) Negative Electrode Similarly to the positive electrode 10, the negative electrode 20 has a long sheet-shaped negative electrode current collector 22 on both surfaces of which a negative electrode mixture layer 24 mainly composed of a negative electrode active material is formed. The negative electrode mixture layer non-formed portion 26 is formed on one side edge in the width direction of the negative electrode 20, and the negative electrode mixture layer non-formed portion 26 is electrically connected to the negative electrode terminal 72 (see FIG. 1). Connected.

  In the present embodiment, the composition of the negative electrode mixture layer 24 is not particularly limited, and may be the same as the composition of the negative electrode mixture layer of a general lithium ion secondary battery. For example, a carbon material such as graphite (graphite), non-graphitizable carbon (hard carbon), easily graphitizable carbon (soft carbon), carbon nanotube, or a combination thereof is used as the negative electrode active material. Can be. From the viewpoint of energy density, it is preferable to use a graphite material (natural graphite (graphite), artificial graphite, or the like) among these carbon materials. Further, the negative electrode mixture layer 24 may include other additives (for example, a binder and a thickener). Examples of the binder include styrene butadiene rubber (SBR), and examples of the thickener include carboxymethyl cellulose (CMC).

(C) Separator A band-shaped sheet material having a predetermined width and having a plurality of minute holes is used for the separator 40. As the separator 40, a separator similar to that used for a general lithium ion secondary battery can be used. For example, a sheet material made of a porous polyolefin resin or the like can be used.

(3) Nonaqueous Electrolyte Further, in the battery case 50 of the lithium ion secondary battery 100 according to the present embodiment, a nonaqueous electrolyte is housed (filled) together with the wound electrode body 80 described above. As such a non-aqueous electrolyte, for example, a supporting solvent is mixed at a predetermined concentration in a mixed solvent of ethylene carbonate (EC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC) (for example, a volume ratio of 3: 4: 3). (For example, about 1 mol / L). As such a supporting salt, a lithium compound containing fluorine, for example, LiPF ₆ , LiBF ₄ , LiCF ₃ SO ₃ or the like is used.

2. Detailed composition of positive electrode mixture layer As described above, the positive electrode mixture layer 14 of the lithium ion secondary battery 100 according to the present embodiment includes a positive electrode active material, trilithium phosphate particles, and other additives. Have been. Hereinafter, each material will be described.

(1) Positive Electrode Active Material The positive electrode active material is a compound capable of reversibly occluding and releasing lithium ions, and is composed of an oxide containing at least lithium (lithium composite oxide). In the present embodiment, the type of the positive electrode active material is not particularly limited, and the same positive electrode active material as a general lithium ion secondary battery can be used. Specific examples of such a positive electrode active material include a lithium nickel composite oxide, a lithium nickel cobalt composite oxide, and a lithium nickel cobalt manganese composite oxide.

(2) Trilithium phosphate particles As described above, the positive electrode mixture layer 14 in the present embodiment contains trilithium phosphate (Li ₃ PO ₄ ) particles. The trilithium phosphate particles allow the acid (eg, hydrogen fluoride (HF)) generated by the decomposition of the nonaqueous electrolyte to be adsorbed on the surface when the lithium ion secondary battery 100 is overcharged. In addition, heat generation during overcharging and elution of metal elements can be suppressed. In the lithium ion secondary battery 100 according to the present embodiment, the content of the trilithium phosphate particles and the specific surface area of the trilithium phosphate particles are defined within a predetermined range.

(A) Content of Trilithium Phosphate Particles In the present embodiment, the content of trilithium phosphate particles is 0.1% when the solid content of the positive electrode mixture layer 16 excluding the trilithium phosphate particles is 100 wt%. It is specified in the range of 88 wt% to 8.8 wt%. If the content of the trilithium phosphate particles in the positive electrode mixture layer 16 is less than 0.88 wt%, the acid generated by the decomposition of the nonaqueous electrolyte cannot be sufficiently adsorbed, and the heat generated during overcharging will not be obtained. It becomes difficult to sufficiently suppress the elution of metal elements and the like. On the other hand, when the content of trilithium phosphate particles exceeds 8.8 wt%, the viscosity of the positive electrode mixture increases significantly, and it becomes difficult to apply the positive electrode mixture on the surface of the positive electrode current collector 12. There is a possibility that the productivity of the positive electrode 10 may decrease.
For this reason, in the present embodiment, the content of trilithium phosphate particles with respect to the positive electrode mixture layer 16 is defined to be in the range of 0.88 wt% to 8.8 wt%. As a result, a lithium ion secondary battery capable of appropriately exerting the function of trilithium phosphate can be obtained with high productivity.

(B) The specific surface area of tricalcium phosphate lithium particles, in the present embodiment, the specific surface area of tricalcium phosphate lithium particles is defined within a range of 0.9m ² /g~20.3m ² / g.
As described above, trilithium phosphate absorbs an acid such as hydrogen fluoride (HF) generated by oxidative decomposition of a non-aqueous electrolyte onto the particle surface, thereby reducing heat generation during overcharge and elution of metal elements. Although it has a function of suppressing, when the specific surface area of the trilithium phosphate particles is too small, it is difficult to properly exert such a function.
On the other hand, when moisture is adsorbed on the surface of the trilithium phosphate particles, a phenomenon occurs in which the reaction resistance in the positive electrode increases, and when the specific surface area of the trilithium phosphate particles is too large, the adsorption of such moisture is likely to occur. There is a possibility that battery performance may be reduced due to an increase in reaction resistance.
Provisions of the specific surface area of tricalcium phosphate lithium particles in the present embodiment ^{(0.9m 2 /g~20.3m} 2 / g), which has been determined on the basis of the above findings, phosphoric acid within this range By defining the specific surface area of the trilithium particles, an acid such as hydrogen fluoride (HF) can be appropriately adsorbed on the surface of the trilithium phosphate particles, and an increase in reaction resistance due to adsorption of water can be prevented. It can be suppressed appropriately.

As described above, in the lithium ion secondary battery according to this embodiment, when the solid content of the positive electrode mixture layer 16 excluding trilithium phosphate particles is 100 wt%, the content of trilithium phosphate particles is 0.1%. defined in the range of 88wt% ~8.8wt%, and defines a specific surface area of tricalcium phosphate lithium particles in the range of 0.9m ² /g~20.3m ² / g.
As a result, it is possible to appropriately suppress heat generation during overcharge, elution of metal elements, and the like without causing a variation in the function of trilithium phosphate, and reduce phosphorus such as a decrease in productivity and an increase in reaction resistance. Problems that may occur due to the addition of trilithium oxide can also be prevented.

(3) Other Additives The positive electrode mixture layer 16 may contain additives such as a conductive agent and a binder, similarly to a general lithium ion secondary battery. As the conductive agent, for example, a carbon material such as carbon black can be used. As the binder, for example, polyvinylidene fluoride (PVDF), polyvinylidene chloride (PVDC), polyethylene oxide (PEO), or the like can be preferably used.
Further, the positive electrode mixture layer 16 may contain a metal element such as Si, Na, K, Cl, Fe, Cu, Zn, Pb, Ni, Co, or Cr. These metal elements are contained in the trilithium phosphate powder when preparing the paste-like positive electrode mixture, and these metal elements are contained in the positive electrode mixture layer 16. In addition, it is possible to suitably suppress heat generation during overcharge, elution of metal elements, and the like, and to prevent problems that may occur due to the addition of trilithium phosphate, such as a decrease in productivity and an increase in reaction resistance. be able to.

In the above-described embodiment, the lithium ion secondary battery has been described as an example of the nonaqueous electrolyte secondary battery disclosed herein. However, such description is intended to limit the application of the present invention. Instead, the present invention can also be applied to non-aqueous electrolyte secondary batteries other than lithium ion secondary batteries. However, as described above, a lithium ion secondary battery (4V class battery) using a positive electrode active material (eg, lithium nickel cobalt manganese composite oxide) having an operating potential of less than 4.3 V (vs. Li ^/ Li ⁺ ). Is particularly preferable as an object to which the present invention is applied, because it has a property of generating a large amount of heat when it is in an overcharged state, and can exert the effect of the present invention more remarkably.

[Test example]
Hereinafter, test examples according to the present invention will be described, but the description of the test examples is not intended to limit the present invention.

  In this test example, first, an experiment A for examining an appropriate content of trilithium phosphate particles will be described, and then an experiment B for examining an appropriate specific surface area of the trilithium phosphate particles will be described.

1. Experiment A
(1) Preparation of Test Examples 1 to 14 In Experiment A, 14 kinds of positive electrode composite materials having different contents of trilithium phosphate particles were prepared, and a 4V-class lithium ion A secondary battery was fabricated, and the performance of the battery after the fabrication was evaluated.

Specifically, for each of Test Examples 1 to 14, a lithium nickel cobalt manganese composite oxide as a positive electrode active material, trilithium phosphate (Li ₃ PO ₄ ) particles, and a conductive material (AB: acetylene) Black) and a binder (PVDF) were dispersed in a dispersion medium (NMP: N-methylpyrrolidone) to prepare a paste-like positive electrode mixture. At this time, as shown in Tables 1 and 2, the content of lithium triphosphate particles (Li ₃ PO ₄ content) when the solid content of the positive electrode mixture excluding trilithium phosphate was 100 wt%, Each test example was different. Then, the prepared positive electrode mixture was applied to both surfaces of a positive electrode current collector (aluminum foil), dried, and then pressed at a predetermined pressure to produce a sheet-shaped positive electrode.

Next, a negative electrode active material (graphite), a binder (SBR: styrene-butadiene copolymer), and a thickener (CMC) are mixed with a dispersion medium (water) to prepare a paste-like negative electrode mixture. The negative electrode mixture was applied to both sides of a sheet-shaped negative electrode current collector (copper foil), dried, and then pressed to produce a sheet-shaped negative electrode.
Then, after laminating the positive electrode and the negative electrode via the separator, the laminated body is wound to produce a wound electrode body, and the wound electrode body is housed in a battery case together with a non-aqueous electrolyte and sealed. Thus, a 4V class lithium ion secondary battery for an evaluation test was produced. The non-aqueous electrolyte was a non-aqueous electrolyte containing a supporting salt (LiPF ₆ ) at a concentration of about 1 mol / liter in a mixed solvent containing EC, DMC, and EMC at a volume ratio of 3: 4: 3. It was used.

(2) Evaluation Test In Experiment A, the battery temperature during overcharge and the paste viscosity of the positive electrode mixture were measured for Test Examples 1 to 14 described above. Specific measurement conditions will be described below.

(A) Measurement of Battery Temperature During Overcharge Each of the 4V-class lithium-ion secondary batteries produced in each test example was charged to 5.1V at a constant current of 20C to overcharge each battery. The battery temperature during overcharge was measured by measuring the temperature at the center of the outside of the battery case of each battery. The measurement results are shown in Table 1, Table 2, and FIG. The measurement results in Tables 1 and 2 are shown as relative evaluations when Test Example 1 is set to 100. In addition, among the two plots in FIG. 3, the diamond-shaped plots show the measurement results of the battery temperature during overcharge.

(B) Measurement of Viscosity of Positive Electrode Mix For each of Test Examples 1 to 14, a part of the positive electrode mix used to form the positive electrode mix layer was sampled, and was taken at room temperature (about 18 ° C. to 25 ° C.). ) For 3 days (72 hours), and then the viscosity was measured at room temperature using an E-type viscometer (rotation speed: 20 rpm). The measurement results are shown in Table 1, Table 2, and FIG. The measurement results in Tables 1 and 2 are shown as relative evaluations when Test Example 1 is set to 100. In addition, among the two plots in FIG. 3, the square plot indicates the measurement result of the viscosity.

(4) Test Results As shown in Tables 1 and 2 and FIG. 3, as the content of trilithium phosphate particles in the positive electrode mixture layer increases, the battery temperature during overcharge decreases. The result was that the viscosity of the mixture was likely to increase. And when each test example is compared in detail, in Test Examples 5 to 14 in which the content of the trilithium phosphate particles is 0.88 wt% or more, the battery temperature is significantly reduced, and It was confirmed that lithium was functioning properly.
On the other hand, in Test Examples 11 to 14 in which the content of trilithium phosphate particles exceeded 8.8 wt%, although the battery temperature during overcharge was almost the same as in Test Example 10, the positive electrode The result showed that the viscosity of the material was greatly increased, and the production of the positive electrode became difficult.
From this, as in Test Examples 5 to 10, by regulating the content of trilithium phosphate particles in the range of 0.88 wt% to 8.8 wt%, the battery temperature during overcharge can be significantly increased. It has been found that the positive electrode can be manufactured with high productivity while suppressing a large increase in paste viscosity.

2. Experiment B
Next, in Experiment B, an experiment for examining an appropriate specific surface area of trilithium phosphate particles was performed.

(1) Preparation of Test Examples 15 to 28 In Experiment B, as shown in Tables 3 and 4 below, in each test example, a paste-like positive electrode using trilithium phosphate particles having different specific surface areas. A mixture was prepared, and a lithium ion secondary battery was fabricated using the positive electrode mixture.
The batteries of Test Examples 15 to 28 were different from those in the above-described Experiment A except that the specific surface area of the trilithium phosphate particles was changed and the content of the trilithium phosphate particles was 2.0 wt%. , And manufactured under the same conditions as in Test Example 7.

(2) Evaluation Test In Experiment B, as an evaluation test, measurement of the battery temperature during overcharge and measurement of the reaction resistance were performed.

(A) Measurement of battery temperature during overcharge With respect to each of the lithium ion secondary batteries of Test Examples 15 to 28, the battery temperature at the time of 5.1 V charge under the same conditions as in Experiment A described above (battery at the time of overcharge) Temperature). The measurement results are shown in Tables 3, 4 and FIG. The measurement results shown in Tables 3 and 4 are shown by relative evaluation with Test Example 15 being 100. In addition, among the two plots in FIG. 4, the diamond-shaped plots show the measurement results of the battery temperature during overcharge.

(B) Measurement of reaction resistance The lithium ion secondary battery of each test example was placed in an environment of −30 ° C., and AC impedance was measured under the conditions of an amplitude of 5 mV and a measurement frequency range of 10,000 to 0.001 Hz. The diameter of the arc shape of the obtained Cole-Cole plot was calculated as the reaction resistance. The measurement results are shown in Tables 3, 4 and FIG. In addition, each measurement result in Table 3 and Table 4 is shown by the relative evaluation which set Test Example 15 to 100. In FIG. 4, a square plot shows the measurement result of the reaction resistance.

(4) Test Results As shown in Table 3, Table 4, and FIG. 4, the result that the battery temperature at the time of overcharging decreased as the specific surface area of the trilithium phosphate particles increased was obtained. And when each test example is compared in detail, the result that the battery temperature at the time of overcharge falls sharply when specific surface area becomes 0.9 m < ² > / g or more like test examples 18 to 28 is obtained. Was. From this, it was found that the function of trilithium phosphate can be more appropriately exerted by setting the specific surface area to 0.9 m ² / g or more.
On the other hand, as in Test Examples 27 and 28, when the specific surface area exceeded 20.3 m ² / g, the result was that the reaction resistance was significantly increased and the battery performance was reduced. Therefore, as in Test Example 18 Test Example 26, by defining the specific surface area of tricalcium phosphate lithium particles in the range of 0.9m ² /g~20.3m ² / g, tricalcium phosphate lithium It was found that the function of (1) can be more appropriately exhibited, and that an increase in reaction resistance can be suppressed.

  As described above, the present invention has been described in detail. However, the above-described embodiments are merely examples, and the invention disclosed herein includes various modifications and alterations of the above-described specific examples.

10 Positive electrode 12 Positive electrode current collector 14 Positive electrode mixture layer 16 Positive electrode mixture layer non-formed portion 20 Negative electrode 22 Negative electrode collector 24 Negative electrode mixture layer 26 Negative electrode mixture layer non-formed portion 40 Separator 50 Battery case 52 Case body 54 Cover Body 70 Positive electrode terminal 72 Negative electrode terminal 80 Wound electrode body 100 Lithium ion secondary battery

Claims (1)

A positive electrode in which a positive electrode mixture layer is formed on a positive electrode current collector, a negative electrode in which a negative electrode mixture layer is formed on a negative electrode current collector, and nonaqueous electrolysis having a fluorine-containing lithium compound as a supporting salt A non-aqueous electrolyte secondary battery comprising:
The positive electrode mixture layer contains at least a positive electrode active material and trilithium phosphate particles,
Here, when the solid content of the positive electrode mixture layer excluding the trilithium phosphate particles is 100 wt%, the content of the trilithium phosphate particles is 0.88 wt% to 8.8 wt%, and the specific surface area of the tricalcium phosphate lithium particles is 0.9m ² /g~20.3m ² / g, a non-aqueous electrolyte secondary battery.

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