Lithium ion secondary battery
A lithium ion secondary battery that can operate in a high-temperature environment of 85° C. The lithium ion secondary battery includes a positive electrode active material that can store and release lithium ions Li′, a positive electrode binder that binds the positive electrode active material, a negative electrode active material that can store and release lithium ions Li + , a negative electrode binder that binds the negative electrode active material, and an electrolytic solution containing an organic solvent and an imide-based lithium salt. The negative electrode active material is previously doped with lithium ions. The positive electrode binder has a Hansen solubility parameter-based relative energy difference (RED) value of more than 1 with respect to the electrolytic solution.
1. A lithium ion secondary battery, comprising:
a positive electrode active material which stores and releases lithium ions;
a positive electrode binder which binds the positive electrode active material;
a negative electrode active material which stores and releases lithium ions;
a negative electrode binder which binds the negative electrode active material; and
an electrolytic solution comprising an organic solvent and an imide-based lithium salt, wherein:
the organic solvent comprises ethylene carbonate, ethyl methyl carbonate, diethyl carbonate and propylene carbonate,
the organic solvent does not comprise dimethyl carbonate,
the negative electrode active material is pre-doped with lithium ions;
the positive electrode binder has a relative energy difference (RED) value greater than 1 , based on a Hansen solubility parameter, relative to the electrolytic solution; and
a doping ratio of the negative electrode active material is 90% to 100%;
wherein
the doping ratio is defined as follows:
doping ratio (%)=N/N t ×100
wherein N is an amount of lithium ions stored in the negative electrode active material at full charge, and N t is an amount of lithium ions that could be stored in the non-predoped negative electrode active material.
2. The lithium ion secondary battery of claim 1 , wherein an upper limit of an operating potential of the positive electrode active material based on Li is less than a predetermined value.
3. The lithium ion secondary battery of claim 2 , wherein:
the positive electrode active material is disposed on a positive electrode current collector, and
the predetermined value is an operating potential of the positive electrode current collector.
4. The lithium ion secondary battery of claim 1 , wherein at least one of the positive electrode binder and the negative electrode binder is polyacrylic acid.