Nonaqueous electrolyte secondary battery
An object of the present invention is to provide a high-energy density nonaqueous electrolyte secondary battery that controls the rise in temperature during short circuiting. Used is a nonaqueous electrolyte secondary battery 1 , including a battery case 2 , and a positive electrode plate 5 having a positive electrode current collector and a positive electrode mixture layer containing a cathode material capable of absorbing and desorbing lithium, a negative electrode plate 6 having a negative electrode current collector and a negative electrode mixture layer containing an anode material capable of absorbing and desorbing lithium, a separator 7 held between the positive and negative electrode plates, and a nonaqueous electrolyte that are enclosed in the battery case, wherein at least one of the positive electrode plate 5 and the negative electrode plate 6 has an electrode plate resistance, as determined in the charged state in the thickness direction when pressurized at 50 kg/cm2, of 0.4 Ω·cm 2 or more.
1. A nonaqueous electrolyte secondary battery, comprising;
a positive electrode plate having a positive electrode current collector and a positive electrode mixture layer containing a cathode material capable of absorbing and desorbing lithium,
a negative electrode plate having a negative electrode current collector and a negative electrode mixture layer containing an anode material capable of absorbing and desorbing lithium,
a separator held between the positive electrode plate and the negative electrode plate,
a nonaqueous electrolyte, and,
a battery case which enclose the positive electrode plate, the negative electrode plate, the separator, and the nonaqueous electrolyte therein,
wherein at least one of the positive electrode plate and the negative electrode plate has an electrode plate resistance, as determined in the charged state and when pressurized at 50 kg/cm 2 , of 0.4Ω·cm 2 or more in the thickness direction,
the positive electrode plate has an insulation layer formed between the positive electrode current collector and the positive electrode mixture layer so that part of the cathode material in the positive electrode mixture layer is brought into contact with the positive electrode current collector,
at least one of the positive electrode mixture layer and/or the negative electrode mixture layer contains an insulative powder material, and
the insulative powder material contains at least one inorganic oxide filler selected from the group consisting of alumina (Al 2 O 3 ), titania (TiO 2 ), silica (SiO 2 O), zirconia (ZrO 2 ), and magnesia (MgO).
2. The nonaqueous electrolyte secondary battery according to claim 1 , wherein the cathode material contains a lithium composite oxide represented by the following General Formula (I):
Li x M 1-y L y O 2 (1)
(in General Formula (I), 0.85≦x≦1.25; 0≦y≦0.5; M represents at least one element selected from the group consisting of Ni and Co; and L represents at least one element selected from the group consisting of alkali-earth elements, transition elements excluding Ni and Co, rare earth elements, group IIIb elements and group IVb elements).
3. The nonaqueous electrolyte secondary battery according to claim 2 , wherein L in General Formula (I) above represents at least one element selected from the group consisting of Al, Mn, Ti, Mg, Zr, Nb, Mo, W and Y.
4. The nonaqueous electrolyte secondary battery according to claim 2 , wherein at least one element selected from the group consisting of Al, Mn, Ti, Mg, Zr, Nb, Mo, W and Y is supported on the surface of the cathode material.
5. The nonaqueous electrolyte secondary battery according to claim 1 , wherein the insulative powder material has a resistivity, as determined at 25° C. as it is pressed to a compression density of 4 g/cm 3 , of 10 10 (Ω·cm) or more.
6. The nonaqueous electrolyte secondary battery according to claim 1 , wherein at least one of the positive electrode plate and the negative electrode plate has a porous insulation layer on the surface.
7. The nonaqueous electrolyte secondary battery according to claim 1 , wherein the separator has a heat-resistant porous insulation layer on the surface.
8. The nonaqueous electrolyte secondary battery according to claim 1 , wherein the anode material contains metal oxide particles containing at least one element selected from the group consisting of Si and Sn.
9. The nonaqueous electrolyte secondary battery according to claim 1 , wherein the positive electrode plate has an insulation layer formed between the positive electrode current collector and the positive electrode mixture layer so that part of the cathode material in the positive electrode mixture layer is brought into contact with the positive electrode current collector, and the negative electrode plate has an insulation layer formed between the negative electrode current collector and the negative electrode mixture layer so that part of the anode material in the negative electrode mixture layer is brought into contact with the negative electrode current collector.
10. The nonaqueous electrolyte secondary battery according to claim 5 , the positive electrode mixture layer or the negative electrode mixture layer contains the insulative powder material of about 1 to 20 parts by mass with respect to 100 parts by mass of the cathode material or the anode material.
11. The nonaqueous electrolyte secondary battery according to claim 1 , wherein the insulation layer comprises a resin composition which contains an inorganic oxide filler of about 50 to 99 mass % therein.
12. The nonaqueous electrolyte secondary battery according to claim 1 , wherein the insulation layer comprises a resin composition which contains an inorganic oxide filler of about 50 to 99 mass % therein.
13. The nonaqueous electrolyte secondary battery according to claim 7 , wherein the heat-resistant porous insulation layer contains a resin component which has a heat deflection temperature of 250° C. or higher.
14. The nonaqueous electrolyte secondary battery according to claim 7 , wherein the heat-resistant porous insulation layer contains an inorganic oxide filler of about 50 to 99 mass %.
15. A nonaqueous electrolyte secondary battery, comprising;
a positive electrode plate having a positive electrode current collector and a positive electrode mixture layer containing a cathode material capable of absorbing and desorbing lithium,
a negative electrode plate having a negative electrode current collector and a negative electrode mixture layer containing an anode material capable of absorbing and desorbing lithium,
a separator held between the positive electrode plate and the negative electrode plate,
a nonaqueous electrolyte, and,
a battery case which encloses the positive electrode plate, the negative electrode plate, the separator, and the nonaqueous electrolyte therein,
wherein at least one of the positive electrode plate and the negative electrode plate has an electrode plate resistance, as determined in the charged state and when pressurized at 50 kg/cm 2 , of 0. 4Ω·cm 2 or more in the thickness direction,
the negative electrode plate has an insulation layer formed between the negative electrode current collector and the negative electrode mixture layer so that part of the anode material in the negative electrode mixture layer is brought into contact with the negative electrode current collector,
at least one of the positive electrode mixture layer and/or the negative electrode mixture layer contains an insulative powder material, and
the insulative powder material contains at least one inorganic oxide filler selected from the group consisting of alumina (Al 2 O 3 ), titania (TiO 2 ), silica (SiO 3 ), zirconia (ZrO 2 ), and magnesia (MgO).