Non-aqueous electrolyte secondary battery
A non-aqueous electrolyte secondary battery has improved battery cycle durability and suppresses internal short-circuits. The non-aqueous electrolyte secondary battery includes a power generating element having a positive electrode, a negative electrode, and a separator including a resin film having a three-layer structure, a ratio of a rated capacity to a pore volume of a positive electrode active material layer being 2.08 Ah/cc or more, a ratio of a battery area to a rated capacity being 7 cm 2 /Ah or more, and a rated capacity being 50 Ah or more, in which a value R represented by Formula 1 is 62 to 110: R = Tortuosity factor × Thickness [ µm ] Porosity ( Formula 1 ) provided that, the average pore diameter is 0.10 to 0.18 μm, the porosity is 0.43 to 0.65, the air permeability is 140 to 305 sec/100 ml, and the thickness is 11 to 25 μm.
1. A non-aqueous electrolyte secondary battery comprising a power generating element including
a positive electrode obtained by forming a positive electrode active material layer containing a positive electrode active material on a surface of a positive electrode current collector,
a negative electrode obtained by forming a negative electrode active material layer containing a negative electrode active material on a surface of a negative electrode current collector, and
a separator including a resin film having a three-layer structure,
a ratio of a rated capacity to a pore volume of the positive electrode active material layer being 2.08 Ah/cc or more, a ratio of a battery area to a rated capacity being 7 cm 2 /Ah or more, and a rated capacity being 50 Ah or more, wherein
a value R of the separator represented by the following Formula 1 is 62 to 110:
R
=
Tortuosity
factor
×
Thickness
[
µm
]
Porosity
(
Formula
1
)
provided that, in Formula 1, a tortuosity factor is a value represented by the following Formula 2:
Tortuosity
factor
=
Air
permeability
[
sec
/
100
ml
]
×
Average
pore
diameter
[
µm
]
×
Porosity
Thickness
[
µm
]
×
25
×
5.18
×
10
-
3
(
Formula
2
)
the average pore diameter is 0.10 to 0.18 μm,
the porosity is 0.43 to 0.65,
the air permeability is 140 to 305 sec/100 ml, and
the thickness is 11 to 25 μm.
2. The non-aqueous electrolyte secondary battery according to claim 1 , wherein the R is 91 to 110.
3. The non-aqueous electrolyte secondary battery according to claim 1 , wherein the R is 81 to 90.
4. The non-aqueous electrolyte secondary battery according to claim 1 , wherein the R is 62 to 80.
5. The non-aqueous electrolyte secondary battery according to claim 1 , wherein the separator has a laminate structure of the resin film and a heat resistant insulating layer.
6. The non-aqueous electrolyte secondary battery according to claim 1 , wherein a constituent of the resin film is at least one of polypropylene and polyethylene.
7. The non-aqueous electrolyte secondary battery according to claim 1 , wherein the non-aqueous electrolyte secondary battery is a flat stack type laminate battery obtained by sealing the power generating element in a battery outer casing body formed of a laminate film containing aluminum.