Lithium ion capacitor

摘要

Provided is a lithium ion capacitor that can maintain a high capacity retention rate and suppress an increase in internal resistance even after high-load charging-discharging is repeated many times and that has long service life because the occurrence of a short circuit due to precipitation of lithium on the negative electrode is prevented.;The lithium ion capacitor comprises a positive electrode, a negative electrode, and an electrolyte solution, the negative electrode including a current collector and electrode layers that contain a negative electrode active material and are formed on front and back surfaces of the current collector, wherein, in the negative electrode, ratios of deviations of respective thicknesses of the electrode layers formed on the front and back surfaces of the current collector from an average of the thicknesses of the electrode layers to the average is −10 to 10%.

主权项

1. A lithium ion capacitor, comprising:
a positive electrode; a negative electrode; and an electrolyte solution, wherein: the negative electrode is doped with lithium ions; the negative electrode comprises a negative electrode current collector and electrode layers comprising a negative electrode active material and formed on front and back surfaces of the negative electrode current collector; in the negative electrode, a thickness T1 of an electrode layer formed on the front surface of the current collector is different than a thickness T2 of an electrode layer formed on the back surface of the current collector; in the negative electrode, an average thickness T0 of the thickness T1 and the thickness T2 is expressed as:
T0=(T1+T2)/2; in the negative electrode, a deviation D1 of the thickness T1 is expressed as:
D1=T1−T0; in the negative electrode, a deviation D2 of the thickness T2 is expressed as:
D2=T2−T0; in the negative electrode, a ratio r1 of the deviation D1 to the average thickness T0 is expressed as:
r1=(D1/T0)×100(%); in the negative electrode, a ratio r2 of the deviation D2 to the average thickness T0 is expressed as:
r2=(D2/T0)×100(%); and in the negative electrode, the ratio r1 and the ratio r2 satisfy the following expressions:
0<|r1|=|r2|≦10(%)r1+r2=0