Lithium Ion Secondary Battery
Provided is a lithium ion secondary battery including: a package; and a power generating element disposed in the package, the power generating element including: a positive electrode; a negative electrode; a separator; and an electrolyte solution, and the separator having a shrinkage rate of 10% or less at 150° C. obtained by a thermomechanical analysis.
1 . A lithium ion secondary battery comprising:
a package; and
a power generating element disposed in the package, the power generating element including:
a positive electrode;
a negative electrode;
a separator; and
an electrolyte solution, wherein the separator has a shrinkage rate of 10% or less at 150° C. obtained by a thermomechanical analysis.
2 . The lithium ion secondary battery according to claim 1 , wherein the separator includes a heat-resistant layer.
3 . The lithium ion secondary battery according to claim 2 , wherein the heat-resistant layer includes particles of metal oxide.
4 . The lithium ion secondary battery according to claim 2 , wherein the heat-resistant layer contains alumina, boehmite, or a mixture thereof.
5 . The lithium ion secondary battery according to claim 1 , wherein the positive electrode active material layer contains lithium nickel cobalt manganese composite oxide with a layered crystal structure represented by a general formula of Li x Ni y Co z Mn (1−y−z) O 2 .
6 . The lithium ion secondary battery according to claim 1 , wherein the positive electrode and the negative electrode have an area of 75 cm 2 or more.