Non-aqueous secondary battery

Abstract

To provide a nonaqueous secondary battery capable of suppressing an increase in battery resistance due to uneven distribution of a nonaqueous electrolytic solution inside an electrode body.SOLUTION: A nonaqueous secondary battery includes an electrode body 20 in which a positive electrode plate 21, a negative electrode plate 24 and a separator 27 are laminated in a lamination direction, and a nonaqueous electrolytic solution. The value of E is 0.48 or more and 0.69 or less when E=A×B / (C×D) where A [mg / cm2] represents the sum of mass of a negative electrode active material included in a negative electrode mixture layer 26 per unit area on each surface of a negative electrode base material 25, B [nm3] represents an amount of lattice volume change of the negative electrode active material when the nonaqueous secondary battery is charged until a SOC is 100% from 0%, C [N] represents an amount of change of load acting on the electrode body 20 in the lamination direction when the nonaqueous secondary battery is charged until the SOC is 100% from 0%, and D [mm / kN] represents the sum of an inverse of spring constant of the positive electrode plate 21 in the lamination direction and an inverse of spring constant of the separator 27.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a non-aqueous secondary battery.

Background Art

[0002] Electric vehicles and hybrid vehicles are equipped with a non-aqueous secondary battery as their power source. A lithium-ion secondary battery, which is an example of a non-aqueous secondary battery, includes an electrode body in which a positive electrode plate and a negative electrode plate are laminated via a separator.

[0003] When the non-aqueous secondary battery is repeatedly charged and discharged at a high rate, the non-aqueous electrolyte is discharged from inside the electrode body as the negative electrode active material included in the negative electrode plate repeatedly expands and contracts. As a result, a bias occurs in the distribution of the non-aqueous electrolyte inside the electrode body, causing a partial shortage of the amount of the non-aqueous electrolyte inside the electrode body and an increase in battery resistance. As an example of a technique for alleviating the bias in the distribution of the non-aqueous electrolyte inside the electrode body, it is known to optimize the balance of the amounts of the non-aqueous electrolyte discharged from each of the positive electrode plate and the negative electrode plate by defining the spring constant in the thickness direction of the positive electrode plate within a predetermined range (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The expanded negative electrode active material presses not only the positive electrode plate but also the separator. Therefore, in order to suppress the bias in the distribution of the non-aqueous electrolyte inside the electrode body, it is necessary to consider not only the deformation behavior of the positive electrode plate accompanying the expansion of the negative electrode active material but also the deformation behavior of the separator.

Means for Solving the Problems

[0006] A non-aqueous secondary battery for solving the above problems includes an electrode body in which a positive electrode plate, a negative electrode plate, and a separator positioned between the positive electrode plate and the negative electrode plate are laminated in a stacking direction, and a non-aqueous electrolyte. The negative electrode plate includes a negative electrode substrate and negative electrode active material layers provided on two surfaces facing in opposite directions of the negative electrode substrate. For the negative electrode plate, the sum of the masses of the negative electrode active material contained in the negative electrode active material layers per unit area on each surface of the negative electrode substrate is defined as A [mg / cm 2 , and in the non-aqueous secondary battery, the change amount of the lattice volume of the negative electrode active material when charged until the state of charge (SOC) becomes from 0% to 100% is defined as B [nm 3 . In the non-aqueous secondary battery, the change amount of the load in the stacking direction acting on the electrode body when charged until the SOC becomes from 0% to 100% is defined as C [N]. In the stacking direction, the sum of the reciprocals of the spring constants of the positive electrode plate and the separator is defined as D [mm / kN]. When E = A × B / (C × D), the value of E is 0.48 or more and 0.69 or less.

[0007] The value of A × B is an index representing the degree of the volume change amount when the negative electrode active material expands and contracts during charge and discharge. Therefore, the value of A × B is an index representing the degree to which the non-aqueous electrolyte is discharged from the negative electrode plate due to the expansion and contraction of the negative electrode active material. The value of C × D has a positive correlation with the displacement amount when the separator and the positive electrode plate are compressed in the stacking direction as the negative electrode active material expands during charging. That is, the value of C × D is an index of the volume change amount (decrease amount) of the separator and the positive electrode plate during charging, and thus is an index representing the degree to which the non-aqueous electrolyte is discharged from the separator and the positive electrode plate during charging. By keeping the ratio of the value of A × B to the value of C × D within an appropriate range, the balance between the amount of the non-aqueous electrolyte discharged from the negative electrode plate and the amount of the non-aqueous electrolyte discharged from the separator and the positive electrode plate during charge and discharge can be appropriately maintained.

[0008] In the above non-aqueous secondary battery, it is preferable that the value of E is 0.56 or more. According to the above configuration, an increase in the resistance of the non-aqueous secondary battery accompanying charge and discharge cycles can be preferably suppressed. In the above non-aqueous secondary battery, it is preferable that the value of C is 1650 N or more and 1700 N or less. According to the above configuration, the amount of non-aqueous electrolyte discharged from the positive electrode plate and the separator during charge and discharge can be appropriately maintained.

[0009] In the above non-aqueous secondary battery, it is preferable that the value of A is 7.0 mg / cm 2 or more and 10.0 mg / cm 2 or less. According to the above configuration, the amount of non-aqueous electrolyte discharged from the negative electrode plate during charge and discharge can be appropriately maintained.

[0010] In the above non-aqueous secondary battery, it is preferable that the value of D is 0.00011 mm / kN or more and 0.00012 mm / kN or less. According to the above configuration, the amount of non-aqueous electrolyte discharged from the positive electrode plate and the separator during charge and discharge can be appropriately maintained.

Effect of the Invention

[0011] According to the present invention, an increase in battery resistance due to uneven distribution of non-aqueous electrolyte inside the electrode body can be suppressed.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

MODE FOR CARRYING OUT THE INVENTION

[0013] Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 13. [Lithium Ion Secondary Battery] As shown in FIG. 1, a lithium ion secondary battery 10, which is an example of a non-aqueous secondary battery, includes a case 11 and an electrode body 20. The case 11 includes a housing portion 11A and a lid body 12. The housing portion 11A has a flat bottomed rectangular outer shape with an opening on the upper side. The housing portion 11A houses the electrode body 20 and a non-aqueous electrolyte. The lid body 12 closes the opening of the housing portion 11A. The case 11 constitutes a sealed battery case in a rectangular parallelepiped shape by attaching the lid body 12 to the housing portion 11A. The case 11 is made of a metal such as aluminum or an aluminum alloy.

[0014] The lid body 12 is provided with a positive external terminal 13A and a negative external terminal 13B. The external terminals 13A and 13B are used for charging and discharging electric power. The positive current collector 20A, which is the end portion on the positive electrode side of the electrode body 20, is electrically connected to the positive external terminal 13A via the positive current collector member 14A. The negative current collector 20B, which is the end portion on the negative electrode side of the electrode body 20, is electrically connected to the negative external terminal 13B via the negative current collector member 14B. Further, the lid body 12 is provided with an injection port 15 for injecting a non-aqueous electrolyte. Note that the shapes of the external terminals 13A and 13B are not limited to the shapes shown in FIG. 1 and may be arbitrary shapes.

[0015] [Electrode body] As shown in FIG. 2, the electrode body 20 is a flat wound body obtained by winding a laminate in which a long positive electrode plate 21 and a negative electrode plate 24 are laminated via a separator 27. The positive electrode plate 21, the negative electrode plate 24, and the separator 27 are laminated so that the longitudinal direction of each coincides with the longitudinal direction D1. The laminate before winding is laminated in the lamination direction D3 (see FIG. 3) in the order of the positive electrode plate 21, the separator 27, the negative electrode plate 24, and the separator 27. The electrode body 20 has a structure in which the positive electrode plate 21 and the negative electrode plate 24 laminated with the separator 27 interposed therebetween are wound around a winding axis L1 extending in the strip-shaped width direction D2. Therefore, the positive electrode plate 21 and the negative electrode plate 24 each constitute a plurality of layers in the electrode body 20. Similarly, each separator 27 constitutes a plurality of layers in the electrode body 20.

[0016] [Positive electrode plate] As shown in FIG. 3, the positive electrode plate 21 includes a positive electrode base material 22 and a positive electrode active material layer 23. The positive electrode base material 22 is a foil-shaped member formed in a long shape. The positive electrode active material layer 23 is provided on each of the two surfaces facing in the opposite direction of the positive electrode base material 22. The positive electrode base material 22 includes a positive electrode side uncoated portion 22A in which the positive electrode base material 22 is exposed without the positive electrode active material layer 23 being formed at one end in the width direction D2.

[0017] The positive electrode substrate 22 is made of a metal foil composed of aluminum or an alloy mainly composed of aluminum. The uncoated positive electrode portion 22A provided in the positive electrode substrate 22 forms the positive electrode current collector portion 20A with the facing surfaces being pressed against each other in the state of the wound body.

[0018] The positive electrode mixture layer 23 is a cured body of a liquid positive electrode mixture paste. The positive electrode mixture paste contains a positive electrode active material, a positive electrode solvent, a positive electrode conductive material, and a positive electrode binder. The positive electrode mixture layer 23 is formed by drying the positive electrode mixture paste and vaporizing the positive electrode solvent. Therefore, the positive electrode mixture layer 23 contains a positive electrode active material, a positive electrode conductive material, and a positive electrode binder.

[0019] As the positive electrode active material, a lithium-containing composite metal oxide capable of occluding and releasing lithium ions, which are charge carriers in the lithium-ion secondary battery 10, is used. The lithium-containing composite oxide is an oxide containing lithium and another metal element other than lithium. The other metal element other than lithium is at least one selected from the group consisting of, for example, nickel, cobalt, manganese, vanadium, magnesium, molybdenum, niobium, titanium, tungsten, aluminum, and iron contained as iron phosphate in the lithium-containing composite oxide.

[0020] For example, the lithium-containing composite oxide is lithium cobalt oxide (LiCoO 2 ), lithium nickel oxide (LiNiO 2 ), or lithium manganate (LiMn 2 O 4 ). For example, the lithium-containing composite oxide is a ternary lithium-containing composite oxide (NCM) containing nickel, cobalt, and manganese, namely lithium nickel cobalt manganese oxide (LiNiCoMnO 2 ). For example, the lithium-containing composite oxide is lithium iron phosphate (LiFePO 4 ).

[0021] As the positive electrode solvent, a solution of NMP (N-methyl-2-pyrrolidone), which is an example of an organic solvent, is used. As the positive electrode conductive material, for example, carbon black such as acetylene black (AB) and ketjen black, carbon fibers such as carbon nanotubes (CNT) and carbon nanofibers, and graphite are used. The positive electrode binder is an example of the resin component contained in the positive electrode mixture paste. As the positive electrode binder, for example, polyvinylidene fluoride (PVDF), polyvinyl alcohol (PVA), styrene butadiene rubber (SBR), etc. are used.

[0022] Note that the positive electrode plate 21 may be provided with an insulating layer at the boundary between the uncoated portion 22A on the positive electrode side and the positive electrode mixture layer 23. The insulating layer includes an inorganic component having insulating properties and a resin component that functions as a binder. The inorganic component is at least one selected from the group consisting of powdered boehmite, titania, and alumina. The resin component is at least one selected from the group consisting of PVDF, PVA, and acrylic.

[0023] [Negative electrode plate] The negative electrode plate 24 includes a negative electrode substrate 25 and a negative electrode mixture layer 26. The negative electrode substrate 25 is a foil-shaped member formed in a long shape. The negative electrode mixture layer 26 is provided on each of the two surfaces facing in the opposite direction of the negative electrode substrate 25. The negative electrode substrate 25 includes a negative electrode side uncoated portion 25A where the negative electrode substrate 25 is exposed without the formation of the negative electrode mixture layer 26 at one end in the width direction D2 and at the end located opposite to the uncoated portion 22A on the positive electrode side.

[0024] The negative electrode substrate 25 is made of a metal foil composed of copper or an alloy mainly containing copper. In the state of the wound body, the opposing surfaces of the negative electrode side uncoated portion 25A are pressed against each other to form the negative electrode side current collecting portion 20B.

[0025] The negative electrode mixture layer 26 is a cured body of a liquid negative electrode mixture paste. The negative electrode mixture paste contains a negative electrode active material, a negative electrode solvent, a negative electrode dispersant, and a negative electrode binder. The negative electrode mixture layer 26 is formed by drying the negative electrode mixture paste and vaporizing the negative electrode solvent. Therefore, the negative electrode mixture layer 26 contains a negative electrode active material, a negative electrode dispersant, and a negative electrode binder. Note that the negative electrode mixture layer 26 may further contain an additive such as a conductive material.

[0026] The negative electrode active material is a material capable of occluding and releasing lithium ions. As the negative electrode active material, for example, carbon materials such as graphite (graphite), non-graphitizable carbon, graphitizable carbon, and carbon nanotubes are used. Further, the negative electrode active material may be composite particles in which graphite particles are coated with an amorphous carbon layer. The graphite particles are particles having a highly crystalline structure in which layers of six-membered rings of carbon are stacked, and are natural graphite, artificial graphite, etc. The graphite particles often have a shape such as a substantially spherical shape or an elliptical spherical shape. The amorphous carbon layer is formed on the surface of the graphite particles by kneading together with the graphite particles while heating a precursor such as petroleum pitch, coal pitch, petroleum coke, coal coke, and a mixture thereof as an amorphous carbon material. The kneaded product is dried by heating at a temperature lower than the graphitization temperature at which the precursor graphitizes in an inert atmosphere. Then, by pulverizing the dried product to separate the single graphite particles, composite particles coated with an amorphous carbon layer are produced.

[0027] As an example, the negative electrode solvent is water. As an example, carboxymethyl cellulose (CMC) can be used as the negative electrode dispersant. The same material as the positive electrode binder can be used as the negative electrode binder. As an example, the negative electrode binder is SBR.

[0028] [Separator] The separator 27 prevents contact between the positive electrode plate 21 and the negative electrode plate 24 and holds the non-aqueous electrolyte between the positive electrode plate 21 and the negative electrode plate 24. When the electrode body 20 is immersed in the non-aqueous electrolyte, the non-aqueous electrolyte penetrates from the end portion to the central portion of the separator 27.

[0029] The separator 27 is a nonwoven fabric made of polypropylene or the like. As the separator 27, for example, a porous polymer film such as a porous polyethylene film, a porous polyolefin film, or a porous polyvinyl chloride film, and an ion conductive polymer electrolyte film can be used.

[0030] [Non-aqueous electrolyte] The non-aqueous electrolyte is a composition in which a supporting salt is contained in a non-aqueous solvent. The non-aqueous solvent is, for example, one or more materials selected from the group consisting of propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate, and ethyl methyl carbonate. As the supporting salt, for example, LiPF 6 , LiBF 4 , LiClO 4 , LiAsF 6 , LiCF 3 SO 3 , LiC 4 F 9 SO 3 , LiN(CF 3 SO 2 ) 2 , LiC(CF 3 SO 2 ) 3 , LiI, or the like, and is one or more lithium compounds (lithium salts) selected therefrom.

[0031] In this embodiment, ethylene carbonate is employed as the non-aqueous solvent. Lithium bisoxalate borate (LiBOB) as a lithium salt as an additive is added to the non-aqueous electrolyte. For example, LiBOB is added to the non-aqueous electrolyte so that the concentration of LiBOB in the non-aqueous electrolyte is 0.001 or more and 0.1 or less [mol / L].

[0032] [Method for manufacturing a lithium ion secondary battery] As shown in FIG. 4, the method for manufacturing the lithium-ion secondary battery 10 includes steps S1 to S6. Step S1 is a source process for manufacturing each of the positive electrode plate 21 and the negative electrode plate 24. In the manufacturing process of the positive electrode plate 21, on two surfaces facing in opposite directions of the positive electrode substrate 22, a positive electrode mixture paste is applied so as to form positive electrode side uncoated portions 22A at both ends in the width direction D2. Then, the positive electrode mixture paste is dried to form a positive electrode mixture layer 23. Next, by pressing the positive electrode mixture layers 23 formed on both surfaces of the positive electrode substrate 22, the thickness of the positive electrode mixture layer 23 is adjusted. Then, the positive electrode substrate 22 is cut at the center in the width direction D2. Through the above steps, two positive electrode plates 21 are manufactured at a time.

[0033] In the manufacturing process of the negative electrode plate 24, on two surfaces facing in opposite directions of the negative electrode substrate 25, a negative electrode mixture paste is applied so as to form negative electrode side uncoated portions 25A at both ends in the width direction D2. Then, the negative electrode mixture paste is dried to form a negative electrode mixture layer 26. Next, by pressing the negative electrode mixture layers 26 formed on both surfaces of the negative electrode substrate 25, the thickness of the negative electrode mixture layer 26 is adjusted. Then, the negative electrode substrate 25 is cut at the center in the width direction D2. Through the above steps, two negative electrode plates 24 are manufactured at a time.

[0034] Step S2 is a process for manufacturing the electrode body 20 using the positive electrode plate 21, the negative electrode plate 24, and the separator 27. Specifically, after laminating the positive electrode plate 21 and the negative electrode plate 24 with the separator 27 in between, they are wound and further pressed flat. Then, the positive electrode side uncoated portion 22A is pressure-welded to form the positive electrode side current collector portion 20A, and the negative electrode side uncoated portion 25A is pressure-welded to form the negative electrode side current collector portion 20B. Through the above procedure, in step S2, the electrode body 20 is manufactured.

[0035] Step S3 is a can-sealing process for housing the electrode body 20 in the case 11. At this time, the positive electrode side current collector portion 20A is electrically connected to the positive electrode external terminal 13A via the positive electrode side current collector member 14A. The negative electrode side current collector portion 20B is electrically connected to the negative electrode external terminal 13B via the negative electrode side current collector member 14B. The upper part of the housing portion 11A is closed by the lid body 12.

[0036] Step S4 is a drying process of removing moisture in the electrode body 20 by heat treatment and a liquid injection process of injecting a non-aqueous electrolyte into the case 11. Through the above procedures, the lithium-ion secondary battery 10 is assembled.

[0037] Step S5 is a charging process of charging the lithium-ion secondary battery 10. Step S6 is an aging process of allowing the lithium-ion secondary battery 10 that has undergone the charging process to stand at a high temperature for a certain period. Through the aging process, metal foreign substances in the lithium-ion secondary battery 10 are dissolved and the SEI film is stabilized. After that, after passing inspections and the like, the manufacturing process of the lithium-ion secondary battery 10 is completed.

[0038] [Increase in battery resistance associated with charge-discharge cycles] As shown in FIG. 5, when the lithium-ion secondary battery 10 is charged, lithium ions are occluded from the surface of the negative electrode active material and enter the inside of the negative electrode active material, causing the crystal lattice of the negative electrode active material to be distorted and the volume of the negative electrode active material to increase. Therefore, when the lithium-ion secondary battery 10 is charged, the volume of the negative electrode binder layer 26 increases, and the positive electrode plate 21 and the separator 27 are pressed in the direction of arrow A1 along the stacking direction D3. Then, the non-aqueous electrolyte is discharged from the positive electrode plate 21 and the separator 27 toward the outside of the electrode body 20.

[0039] As shown in FIG. 6, when the lithium-ion secondary battery 10 is discharged, lithium ions are released from the negative electrode active material, causing the volume of the negative electrode active material to decrease. Then, when the lithium-ion secondary battery 10 is discharged, the volume of the negative electrode binder layer 26 decreases in the direction of arrow A2 along the stacking direction D3, and the non-aqueous electrolyte is discharged from the negative electrode binder layer 26 toward the outside of the electrode body 20.

[0040] When the lithium-ion secondary battery 10 is repeatedly charged and discharged, the non-aqueous electrolyte is discharged from the inside of the electrode body 20 as the negative electrode active material repeatedly expands and contracts. At this time, when the difference between the discharge amount of the non-aqueous electrolyte from the positive electrode plate 21 and the separator 27 during charging and the discharge amount of the non-aqueous electrolyte from the negative electrode plate 24 during discharging is large, the distribution of the non-aqueous electrolyte inside the electrode body 20 becomes uneven. The uneven distribution of the non-aqueous electrolyte inside the electrode body 20 causes an increase in battery resistance due to a shortage of the amount of the non-aqueous electrolyte in a part inside the electrode body 20. The above phenomenon is particularly likely to occur when the lithium-ion secondary battery 10 is repeatedly charged and discharged at a high output (high rate).

[0041] The lithium-ion secondary battery 10 is determined such that the value of E represented by the following parameters A to D is within a predetermined numerical range in order to suppress the uneven distribution of the non-aqueous electrolyte inside the electrode body 20. The value of E is expressed as E = A × B / (C × D).

[0042] Hereinafter, each parameter of A to D will be described. The value of A is the sum of the masses of the negative electrode active material contained in the negative electrode mixture layer 26 per unit area on each surface of the negative electrode substrate 25 for the negative electrode plate 24 constituting one layer of the electrode body 20 [mg / cm 2 . The value of A can be calculated, for example, using the basis weight [mg / cm 2 of the negative electrode mixture layer 26 per unit area when manufacturing the negative electrode plate 24 and the mass ratio of the negative electrode active material in the negative electrode mixture layer 26 in step S1. For example, the value of A can be changed by changing the basis weight of the negative electrode mixture layer 26 per unit area when manufacturing the negative electrode plate 24, the mass ratio of the negative electrode active material in the negative electrode mixture layer 26, or both in step S1.

[0043] The lower limit of A is 7.0 mg / cm 2 or more, more preferably 7.26 mg / cm 2The above is the case. The upper limit of A is 10.0 mg / cm from the viewpoint of suppressing an excessive decrease in the amount of the non-aqueous electrolyte discharged from the negative electrode plate 24 during charge and discharge. 2 Hereinafter, it is more preferably 9.41 mg / cm 2 or less.

[0044] The value of B is the change amount of the lattice volume of the negative electrode active material [nm 3 when the lithium ion secondary battery 10 is charged from SOC 0% to 100%. For example, when the negative electrode active material is graphite, the unit cell in the state of α-graphite at SOC 0% and the unit cell in the state of LiC 6 in which graphite occludes lithium at SOC 100% differ in both the number of atoms constituting the unit cell and the size of the unit cell.

[0045] As shown in FIG. 7, for example, α-graphite at SOC 0% is composed of graphene G formed in a sheet shape by carbon atoms connected in a hexagonal mesh shape and stacked. In α-graphite, the odd-numbered layer graphene G indicated by a solid line and the even-numbered layer graphene G indicated by a broken line in FIG. 7 are arranged in a state of being shifted from each other in the in-plane direction (two-dimensional direction) of the graphene G. The a-axis lattice constant a 1 of the unit cell UC1 included in α-graphite is √3 times the length of one side of the six-membered ring (carbon-carbon distance in the six-membered ring). The c-axis lattice constant c 1 of the unit cell UC1 included in α-graphite is twice the plane-to-plane distance between adjacent graphene Gs in the c-axis direction in which the graphene Gs are stacked. The unit cell UC1 included in α-graphite contains 4 carbon atoms.

[0046] As shown in FIG. 8, LiC 6 at SOC 100% is an intercalation compound in which lithium (Li) is occluded between the layers of graphene G included in α-graphite. In LiC 6 , since the in-plane shift between the odd-numbered layer graphene G and the even-numbered layer graphene G is eliminated with the occlusion of lithium, the carbon atoms of the graphene G overlap in the c-axis direction. LiC 6The lattice constant a of the unit cell UC2 included in 2 is three times the length of one side of the six-membered ring. The lattice constant c of the unit cell UC2 in the c-axis direction 2 is the interplanar distance between adjacent graphene G planes in the c-axis direction. LiC 6 The unit cell UC2 included therein contains six carbon atoms.

[0047] The method for calculating the lattice volume change amount of the negative electrode active material accompanying the occlusion of lithium is to extract crystal lattices having the same number of carbon atoms from α-graphite at SOC0% and LiC 6 respectively. Then, the value obtained by subtracting the volume of the crystal lattice extracted from α-graphite from the volume of the crystal lattice extracted from LiC 6 is the lattice volume change amount of the negative electrode active material. In the calculation of the lattice volume change amount, the crystal lattices extracted from each of α-graphite and LiC 6 contain, for example, 12 carbon atoms which is the least common multiple of the number of carbon atoms included in the unit cell UC1 of α-graphite and the number of carbon atoms included in the unit cell UC2 of LiC 6 .

[0048] As shown in FIG. 7, the crystal lattice CL1 extracted from α-graphite is a parallelepiped straddling three layers of graphene G, and includes, for example, a rhombic upper bottom surface and a lower bottom surface located on the odd-numbered layers at both ends of the three layers, and four side surfaces connecting the upper bottom surface and the lower bottom surface. In the crystal lattice CL1, the four sides extending in the c-axis direction overlap with the carbon atoms located in the graphene G of the even-numbered layers. The length X1 of one side of the rhombus of the upper bottom surface and the lower bottom surface is three times the length of one side of the six-membered ring, and is √3 times the lattice constant a of the a-axis of the unit cell UC1 1 . Also, in the crystal lattice CL1, the lengths of the four sides extending in the c-axis direction are twice the interplanar distance between adjacent graphene G planes in the c-axis direction, and are the same length as the lattice constant c of the c-axis of the unit cell UC1 1 .

[0049] As shown in FIG. 8, the crystal lattice CL2 extracted from LiC 6 is, for example, LiC 6It is a parallelepiped formed by stacking two unit cells UC2 provided in the c-axis direction. The crystal lattice CL2 is a parallelepiped straddling three layers of graphene G, and includes a rhombic upper bottom surface and lower bottom surface located on the two outermost layers of the three layers of graphene G, and four side surfaces connecting the upper bottom surface and the lower bottom surface. In the crystal lattice CL2, the four sides extending in the c-axis direction respectively overlap with lithium atoms occluded between the planes of graphene G. The length X2 of one side of the rhombus of the upper bottom surface and the lower bottom surface is three times the length of one side of the six-membered ring, and is the same as the a-axis lattice constant a of the unit cell UC2 2 and has the same length. Also, in the crystal lattice CL2, the length of the four sides extending in the c-axis direction is twice the interplanar distance between adjacent graphene G planes in the c-axis direction, and is twice the c-axis lattice constant c of the unit cell UC2 2

[0050] As shown in FIG. 9, for example, the lattice volume M 1 〔nm 3 〕 of the crystal lattice CL1 extracted from α-graphite at SOC0% is expressed by Equation (1) using the a-axis lattice constant a 1 〔Å〕 and the c-axis lattice constant c 1 〔Å〕 of the unit cell UC1 of α-graphite

[0051] As shown in FIG. 10, for example, the lattice volume M 6 〔nm 2 〕 of the crystal lattice CL2 extracted from LiC 3 in the state of SOC100% is expressed by Equation (2) using the a-axis lattice constant a 6 〔Å〕 and the c-axis lattice constant c 2 〔Å〕 of the unit cell UC2 of LiC 2 〔Å〕

[0052] Note that the values of the a-axis lattice constant a 1 and the c-axis lattice constant c 1 of α-graphite can be obtained from the peaks obtained by XRD (X-ray diffraction method) for the negative electrode active material at SOC0% based on Bragg's law and the relationship with the interplanar spacing of each Miller index. Similarly, the a-axis lattice constant a 6 and the c-axis lattice constant c 2 of LiC​2 The value can be determined based on the Bragg's law and the relationship with the interplanar spacing of each Miller index from the peaks obtained by XRD for the negative electrode active material at SOC 100%.

[0053] The value of B is the lattice volume M of the crystal lattice CL2 at SOC 100% 2 〔nm 3 〕minus the lattice volume M of the crystal lattice CL1 at SOC 0% 1 〔nm 3 〕, that is, B = M 2 - M 1 It is expressed as. Note that, for example, the value of B can be changed by changing the type of material used as the negative electrode active material. The value of B is, as an example, 0.013 nm 3 or more and 0.016 nm 3 or less.

[0054] In α - graphite, the lattice volume M of the crystal lattice CL1 1 is three times the volume of the unit cell UC1. Also, in LiC 6 , the lattice volume M of the crystal lattice CL2 2 is two times the volume of the unit cell UC2. Therefore, the value of B may also be obtained by subtracting the value obtained by multiplying the volume of the unit cell UC1 in α - graphite in the state of SOC 0% by 3 from the value obtained by multiplying the volume of the unit cell UC2 in LiC in the state of SOC 100% by 2. 6

[0055] In this embodiment, "X'Pert - PRO MPD" (manufactured by Malvern Panalytical) was used as the XRD measuring device. "PIXcel1D detector" (manufactured by Malvern Panalytical) was used as the detector. A Cu target was used as the X - ray tube. The step width was set to 0.013°. The scanning speed was set to 0.0417° / sec.

[0056] The value of A×B has a positive correlation with the volume change amount (increase amount) of the negative electrode active material contained in the negative electrode mixture layer 26 per unit area when the lithium-ion secondary battery 10 is charged until the state of charge (SOC) changes from 0% to 100%. Also, the value of A×B has a positive correlation with the volume change amount (decrease amount) of the negative electrode active material contained in the negative electrode mixture layer 26 per unit area when the lithium-ion secondary battery 10 is discharged until the SOC changes from 100% to 0%. Therefore, the value of A×B has a positive correlation with the amount of the electrolyte discharged from the negative electrode plate 24 due to the expansion and contraction of the negative electrode active material accompanying the charge and discharge of the lithium-ion secondary battery 10. That is, the value of A×B is an index representing the degree of the non-aqueous electrolyte discharged from the negative electrode plate 24 due to the expansion and contraction of the negative electrode active material accompanying the charge and discharge of the lithium-ion secondary battery 10.

[0057] In the state of the electrode body 20, the particle size (median diameter D50) of the negative electrode active material is, for example, 5 μm or more and 30 μm or less. The state where the particle size of the negative electrode active material is within the above range is an example of a state in which the value of A×B has a positive correlation with the amount of the non-aqueous electrolyte discharged from the negative electrode plate 24 due to the expansion and contraction of the negative electrode active material accompanying the charge and discharge of the lithium-ion secondary battery 10.

[0058] The value of C is the change amount [N] of the load in the stacking direction D3 acting on the electrode body 20 when the lithium-ion secondary battery 10 is charged from an SOC of 0% to 100%. When the lithium-ion secondary battery 10 is charged, the negative electrode active material in the negative electrode mixture layer 26 expands, and thus a load in the stacking direction D3 acts on the electrode body 20. That is, the value of C is the load acting on the positive electrode plate 21 and the separator 27 accompanying the expansion of the negative electrode active material when the lithium-ion secondary battery 10 is charged. The value of C can be calculated, for example, using the value measured by a load cell for the change in load when the lithium-ion secondary battery 10 and the load cell are sandwiched between two restraint plates and charged from an SOC of 0% to an SOC of 100%.

[0059] The upper limit of C is, from the viewpoint of suppressing an excessive increase in the amount of the non-aqueous electrolyte discharged from the positive electrode plate 21 and the separator 27 during charge and discharge, for example, 1700 N or less, more preferably 1699 N or less. Further, the lower limit of C is, from the viewpoint of suppressing an excessive decrease in the amount of the non-aqueous electrolyte discharged from the positive electrode plate 21 and the separator 27 during charge and discharge, for example, 1650 N or more, more preferably 1652 N or more.

[0060] The value of D is, in the stacking direction D3, the reciprocal of the spring constant K 1 [kN / mm] of the positive electrode plate 21 constituting one layer of the electrode body 20 and the spring constant K 2 [kN / mm] of the separator 27 constituting one layer of the electrode body 20, and is the sum [mm / kN].

[0061] The value of the spring constant K 1 of the positive electrode plate 21 can be obtained from the displacement amount when a predetermined load is applied to the positive electrode plate 21 before forming the electrode body 20 in the stacking direction D3. For example, for a laminate in which 65 samples of a plurality of positive electrode plates 21 before forming the electrode body 20 are cut to a size of 55 mm × 90 mm so as not to include the uncoated portion 22A on the positive electrode side, a load of 1500 kgf is applied in the stacking direction D3. Then, the spring constant K 1 of each positive electrode plate 21 can be obtained from the displacement amount of the laminate with respect to the load in the range from 1000 kgf to 1500 kgf. Note that, for example, the spring constant K 1 of the positive electrode plate 21 can be changed by changing the amount of the positive electrode mixture layer 23 or changing the pressing amount when adjusting the thickness of the positive electrode mixture layer 23.

[0062] Incidentally, the value of the spring constant K 2 of the separator 27 is the spring constant K 1It can be calculated using a similar concept to the value of 2 For example, with respect to a laminate formed by stacking 130 samples of a plurality of separators 27 before forming the electrode body 20, which are cut to a size of 55 mm × 90 mm, a load of 1500 kgf is applied in the stacking direction D3. Then, the spring constant K 2 of each separator 27 can be obtained from the displacement amount of the laminate with respect to the load in the range from 1000 kgf to 1500 kgf. Note that by changing the material and porosity (density) of the separator 27, the value of the spring constant K

[0063] The lower limit of D is 0.00011 mm / kN or more, more preferably 0.000113 mm / kN or more, from the viewpoint of suppressing the excessive decrease in the amount of non-aqueous electrolyte discharged from the positive electrode plate 21 and the separator 27 during charge and discharge. The upper limit of D is 0.00012 mm / kN or less, more preferably 0.000117 mm / kN or less, from the viewpoint of suppressing the excessive increase in the amount of non-aqueous electrolyte discharged from the positive electrode plate 21 and the separator 27 during charge and discharge.

[0064] The value of C×D has a positive correlation with the displacement amount when the positive electrode plate 21 and the separator 27 are compressed in the stacking direction D3 due to the load acting on the positive electrode plate 21 and the separator 27 as the negative electrode active material expands during charging. That is, the value of C×D has a positive correlation with the volume change amount (decrease amount) of the positive electrode plate 21 and the separator 27 during charging. Therefore, the value of C×D serves as an index representing the degree to which non-aqueous electrolyte is discharged from the positive electrode plate 21 and the separator 27 during charge and discharge.

[0065] From the above, the value of E is the ratio of A×B, which is an index representing the degree to which non-aqueous electrolyte is discharged from the negative electrode plate 24, to C×D, which is an index representing the degree to which non-aqueous electrolyte is discharged from the positive electrode plate 21 and the separator 27 during charge and discharge. Therefore, the value of E serves as an index indicating whether the balance between the amount of non-aqueous electrolyte discharged from the negative electrode plate 24 and the amount of non-aqueous electrolyte discharged from the positive electrode plate 21 and the separator 27 during charge and discharge is appropriate.

[0066] The lower limit of the value of E is 0.48 or more, preferably 0.54 or more, more preferably 0.56 or more. By setting the value of E to be equal to or higher than the above lower limit, it is possible to suppress the amount of non-aqueous electrolyte discharged from the positive electrode plate 21 and the separator 27 from becoming excessively large compared to the amount of non-aqueous electrolyte discharged from the negative electrode plate 24 during charge and discharge. In particular, if the value of E is 0.56 or more, it is possible to suitably reduce the increase in resistance after charge and discharge cycles. The upper limit of the value of E is 0.69 or less, preferably 0.68 or less. By setting the value of E to be equal to or lower than the above upper limit, it is possible to suppress the amount of non-aqueous electrolyte discharged from the negative electrode plate 24 from becoming excessively large compared to the amount of non-aqueous electrolyte discharged from the positive electrode plate 21 and the separator 27 during charge and discharge.

[0067] [Examples] Hereinafter, the relationship between the rate of increase in resistance after charge and discharge cycles with respect to the value of E will be described using Examples 1 to 4 and Comparative Examples 1 to 3. Note that the following examples are an example for explaining the effects of the above-described embodiments and do not limit the present invention. The tables in FIGS. 11 and 12 show the items listed below regarding the materials and physical property values of the positive electrode plate 21, the negative electrode plate 24, and the separator 27 used in Examples 1 to 4 and Comparative Examples 1 to 3.

[0068] Regarding the positive electrode plate 21, the types of positive electrode active material and conductive material in the positive electrode mixture layer 23, the sum of the masses of the positive electrode active material contained in the positive electrode mixture layer 23 per unit area on each surface of the positive electrode substrate 22 (mg / cm 2 ), the average density of the positive electrode mixture layer 23 (g / cm 3 ), and the spring constant K 1 (kN / mm) in the stacking direction D3 of the positive electrode plate 21 are shown in FIG. 11. Regarding the negative electrode plate 24, the type of negative electrode active material in the negative electrode mixture layer 26, the sum of the masses of the negative electrode active material contained in the negative electrode mixture layer 26 per unit area on each surface of the negative electrode substrate 25 (parameter A, mg / cm 2 ), the change amount of the lattice volume of the negative electrode active material when charged from SOC = 0% to 100% (parameter B, nm 3) and the average density of the negative electrode binder layer 26 is shown in FIG. 11. In the table in FIG. 11, both amorphous graphite 1 and amorphous graphite 2 are obtained by spheroidizing flaky natural graphite and then coating its surface with amorphous graphite. Note that amorphous graphite 1 has a particle size (median diameter D50) of 11 μm. Amorphous graphite 2 has a particle size (median diameter D50) of 7 μm.

[0069] Regarding the separator 27, the thickness per sheet of the separator 27 and the spring constant K 2 (kN / mm) in the stacking direction D3 of the separator 27 are shown in FIG. 11. Also, the values of the parameters C (N), D (mm / kN), A×B, C×D, E, and the resistance increase rates of Examples 1 to 4 and Comparative Examples 1 to 3 after charge and discharge cycles are shown in FIG. 12.

[0070] Note that in order to measure the resistance increase rate, in an environment of 25°C, after charging for 10 seconds by constant current charging at 30C, a high-rate charge and discharge cycle of discharging for 100 seconds by constant current discharging at 3C was repeated 1600 times. At this time, the resistance value after 1 charge and discharge cycle and the resistance value after 1600 cycles were measured. Then, the increase rate of the resistance value after 1600 cycles based on the resistance value after 1 cycle was defined as the resistance increase rate. Also, the resistance value was calculated from the voltage drop 10 seconds after the start of discharge when the battery was discharged at 30C from a charged state of SOC60% in an environment of 25°C.

[0071] [Example 1] In Example 1, the spring constant K 1 in the stacking direction D3 of the positive electrode plate 21 was 12869 kN / mm. In the negative electrode plate 24, the value of A was 9.41 mg / cm 2 , the value of B was 0.014 nm 3 . The spring constant K 2 in the stacking direction D3 of the separator 27 was 25624 kN / mm. Also, the value of C was 1661 N, the value of D was 0.000117 mm / kN, the value of A×B was 0.13, the value of C×D was 0.194, and the value of E was 0.68.

[0072] [Example 2] In Example 2, the spring constant K in the stacking direction D3 of the positive electrode plate 21 1 was 12869 kN / mm. In the negative electrode plate 24, the value of A was 9.41 mg / cm 2 , the value of B was 0.014 nm 3 . The spring constant K in the stacking direction D3 of the separator 27 2 was 25624 kN / mm. Also, the value of C was 1652 N, the value of D was 0.000117 mm / kN, the value of A×B was 0.13, the value of C×D was 0.193, and the value of E was 0.68.

[0073] [Example 3] In Example 3, the spring constant K in the stacking direction D3 of the positive electrode plate 21 1 was 13304 kN / mm. In the negative electrode plate 24, the value of A was 7.81 mg / cm 2 , the value of B was 0.014 nm 3 . The spring constant K in the stacking direction D3 of the separator 27 2 was 25624 kN / mm. Also, the value of C was 1699 N, the value of D was 0.000114 mm / kN, the value of A×B was 0.11, the value of C×D was 0.194, and the value of E was 0.56.

[0074] [Example 4] In Example 4, the spring constant K in the stacking direction D3 of the positive electrode plate 21 1 was 13497 kN / mm. In the negative electrode plate 24, the value of A was 7.26 mg / cm 2 , the value of B was 0.014 nm 3 . The spring constant K in the stacking direction D3 of the separator 27 2 was 25624 kN / mm. Also, the value of C was 1661 N, the value of D was 0.000113 mm / kN, the value of A×B was 0.10, the value of C×D was 0.188, and the value of E was 0.54.

[0075] [Comparative Example 1] In Comparative Example 1, the spring constant K in the stacking direction D3 of the positive electrode plate 21 1 was 10688 kN / mm. In the negative electrode plate 24, the value of A was 6.90 mg / cm2 The value of B was 0.014 nm 3 The spring constant K in the stacking direction D3 of the separator 27 2 was 25624 kN / mm. Also, the value of C was 1704 N, the value of D was 0.000133 mm / kN, the value of A×B was 0.10, the value of C×D was 0.226, and the value of E was 0.43.

[0076] [Comparative Example 2] In Comparative Example 2, the spring constant K in the stacking direction D3 of the positive electrode plate 21 1 was 10688 kN / mm. In the negative electrode plate 24, the value of A was 6.90 mg / cm 2 and the value of B was 0.014 nm 3 The spring constant K in the stacking direction D3 of the separator 27 2 was 23929 kN / mm. Also, the value of C was 1954 N, the value of D was 0.000135 mm / kN, the value of A×B was 0.10, the value of C×D was 0.265, and the value of E was 0.36.

[0077] [Comparative Example 3] In Comparative Example 3, the spring constant K in the stacking direction D3 of the positive electrode plate 21 1 was 12869 kN / mm. In the negative electrode plate 24, the value of A was 9.41 mg / cm 2 and the value of B was 0.014 nm 3 The spring constant K in the stacking direction D3 of the separator 27 2 was 25624 kN / mm. Also, the value of C was 1602 N, the value of D was 0.000117 mm / kN, the value of A×B was 0.13, the value of C×D was 0.187, and the value of E was 0.70.

[0078] [Evaluation] As shown in FIG. 13, the points P11 to P14 plotted in the graph 100 represent the resistance increase rates with respect to the value of E in Examples 1 to 4. The points P21 to P23 plotted in the graph 100 represent the resistance increase rates with respect to the value of E in Comparative Examples 1 to 3. The curve 101 in the graph 100 is an approximate curve based on the plurality of points P11 to P14 and the points P21 to P23, and is an approximate curve representing the change in the resistance increase rate with respect to the value of E.

[0079] In Examples 1 to 4 where the value of E satisfied 0.48 or more and 0.69 or less, the resistance increase rate after the charge and discharge cycles was about 1.09 to 1.12. In particular, in Example 3 where the value of E was 0.56, the resistance increase rate after the charge and discharge cycles became the lowest value.

[0080] On the other hand, in Comparative Examples 1 and 2 where the value of E was less than 0.48, the resistance increase rate after the charge and discharge cycles was about 1.19 to 1.20. That is, it was confirmed that in Comparative Examples 1 and 2, the resistance increase rate after the charge and discharge cycles was higher than that in Examples 1 to 4. The increase in the resistance increase rate in Comparative Examples 1 and 2 was due to the fact that the amount of the non-aqueous electrolyte discharged from the negative electrode plate 24 during charge and discharge was less than the amount of the non-aqueous electrolyte discharged from the positive electrode plate 21 and the separator 27.

[0081] Further, in Comparative Example 3 where the value of E exceeded 0.69, the resistance increase rate after the charge and discharge cycles was about 1.32. That is, it was confirmed that in Comparative Example 3, the resistance increase rate after the charge and discharge cycles was higher than that in Examples 1 to 4. The increase in the resistance increase rate in Comparative Example 3 was due to the fact that the amount of the non-aqueous electrolyte discharged from the positive electrode plate 21 and the separator 27 during charge and discharge was less than the amount of the non-aqueous electrolyte discharged from the negative electrode plate 24. From the above, it was confirmed that by setting the value of E within the range of 0.48 or more and 3.05 or less, an increase in the resistance increase rate after the charge and discharge cycles can be suppressed.

[0082] [Effects of the Embodiment] According to the above embodiment, the following effects can be obtained. (1) By keeping the value of E within an appropriate range, it is possible to appropriately maintain the balance between the amount of non-aqueous electrolyte discharged from the negative electrode plate 24 and the amount of non-aqueous electrolyte discharged from the positive electrode plate 21 and the separator 27 during charge and discharge. In particular, if the value of E is 0.56 or more, an increase in the resistance of the lithium-ion secondary battery 10 associated with the charge and discharge cycle can be preferably suppressed.

[0083] (2) When the value of C is 1700 N or less, more preferably 1699 N or less, it is possible to suppress an excessive increase in the amount of non-aqueous electrolyte discharged from the positive electrode plate 21 and the separator 27 during charge and discharge. When the value of C is 1650 N or more, more preferably 1652 N or more, it is possible to suppress an excessive decrease in the amount of non-aqueous electrolyte discharged from the positive electrode plate 21 and the separator 27 during charge and discharge.

[0084] (3) When the value of A is 7.0 mg / cm 2 or more, more preferably 7.26 mg / cm 2 or more, it is possible to suppress an excessive decrease in the amount of non-aqueous electrolyte discharged from the negative electrode plate 24 during charge and discharge. When the value of A is 10.0 mg / cm 2 or less, more preferably 9.41 mg / cm 2 or less, it is possible to suppress an excessive decrease in the amount of non-aqueous electrolyte discharged from the negative electrode plate 24 during charge and discharge.

[0085] (4) When the value of D is 0.00011 mm / kN, more preferably 0.000113 mm / kN or more, it is possible to suppress an excessive decrease in the amount of non-aqueous electrolyte discharged from the positive electrode plate 21 and the separator 27 during charge and discharge. When the value of D is 0.00012 mm / kN or less, more preferably 0.000117 mm / kN, it is possible to suppress an excessive increase in the amount of non-aqueous electrolyte discharged from the positive electrode plate 21 and the separator 27 during charge and discharge.

[0086] [Modified Example] Note that the above embodiment can be implemented with the following modifications. ·If it is possible to appropriately maintain the balance between the amount of non-aqueous electrolyte discharged from the positive electrode plate 21 and the separator 27 and the amount of non-aqueous electrolyte discharged from the negative electrode plate 24 during charge and discharge, the values of C and D are not limited. For example, the value of C may be less than 1650 N, or the value of C may be more than 1700 N. For example, the value of D may be less than 0.00011 mm / kN, or the value of D may be more than 0.00012 mm / kN.

[0087] ·If it is possible to appropriately maintain the balance between the amount of non-aqueous electrolyte discharged from the negative electrode plate 24 and the amount of non-aqueous electrolyte discharged from the positive electrode plate 21 and the separator 27 during charge and discharge, the value of A is not limited. For example, the value of A may be less than 7.0 mg / cm 2 and may be more than 10.0 mg / cm 2 For example, the value of B may be less than 0.013 nm 3 and may be more than 0.016 nm 3

[0088] ·If the value of E is within the range of 0.48 or more and 0.69 or less, the numerical value is not limited. For example, the value of E may be 0.48 or more and less than 0.56. ·The electrode body 20 may not be a wound body, but may be a laminate in which the positive electrode plate 21 and the negative electrode plate 24 are laminated via a separator 27 and housed in a case 11.

[0089] ·The lithium-ion secondary battery 10 may be another non-aqueous secondary battery, for example, a nickel-metal hydride storage battery. ·The lithium-ion secondary battery 10 may be mounted on a computer, other electronic devices, in addition to an automatic transporter, a special vehicle for cargo handling, an electric vehicle, a hybrid vehicle, etc., and may also be a component of other systems. For example, it may be provided in a moving body such as a ship or an aircraft, or may be a power supply system that supplies power to a building or a home where a secondary battery is installed via a substation from a power plant.

Explanation of reference numerals

[0090] D3…Stacking direction 10…Lithium-ion secondary battery 11…Case 20…Electrode body 21…Positive electrode plate 22…Positive electrode substrate 23…Positive electrode mixture layer 24…Negative electrode plate 25…Negative electrode substrate 26…Negative electrode mixture layer 27…Separator

Claims

1. A non-aqueous secondary battery comprising an electrode body in which a positive electrode plate, a negative electrode plate, and a separator positioned between the positive electrode plate and the negative electrode plate are laminated in a stacking direction, and a non-aqueous electrolyte solution, wherein the negative electrode plate includes a negative electrode substrate and negative electrode mixture layers provided on two surfaces facing in opposite directions of the negative electrode substrate, the negative electrode mixture layer contains a negative electrode active material that is a carbon material, Let the sum of the masses of the negative electrode active material contained in the negative electrode binder layer per unit area on each surface of the negative electrode substrate be A [mg / cm ２ , In the non-aqueous secondary battery, the change in the lattice volume of the negative electrode active material when charged until the SOC becomes from 0% to 100% is defined as B [nm ３ , and in the non-aqueous secondary battery, when charging is performed until the state of charge (SOC) becomes from 0% to 100%, the amount of change in the load in the stacking direction acting on the electrode body is defined as C [N], in the stacking direction, the sum of the reciprocal of the spring constant of the positive electrode plate and the reciprocal of the spring constant of the separator is defined as D [mm / kN], when E = A × B / (C × D), the value of E is 0.48 or more and 0.69 or less non-aqueous secondary battery.

2. the value of E is 0.56 or more the non-aqueous secondary battery according to Claim 1.

3. the value of C is 1650 N or more and 1700 N or less the non-aqueous secondary battery according to Claim 1 or 2.

4. The value of A is 7.0 mg / cm ２ or more and 10.0 mg / cm ２ or less the non-aqueous secondary battery according to Claim 3.

5. the value of D is 0.00011 mm / kN or more and 0.00012 mm / kN or less the non-aqueous secondary battery according to Claim 4.

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