Polarization Study of a Lithium-ion Battery with an Extra Positive Electrode Using Eight Reference Electrodes

Deterioration rate of a lithium-ion battery can be accelerated by the existence of an extra positive electrode (P2) where does’t face to the negative electrode. Therefore, the size of the positive electrode (P1) is designed smaller than the size of the negative electrode (N1) with a lithium-ion battery. However, the mechanism was not yet made clear. Eight reference electrodes were embedded around a cell which connected with P2 through an ammeter, and electrical potential behavior in a horizontal plane of the cell was studied against the nearest reference electrode. When the charge and discharge of the cell was performed, remarkable potential shifts occurred and the electricity charged from P1 to P2 was observed. Electric potential distributions in a horizontal plane of the cell were also analyzed with contour maps. Lithium ions must be supplied from P2 to N1 when the charge of the cell is performed and they must be also supplied from P2 to P1 when it discharges. The ion conduction resistance between P2 and P1 was estimated as 250 Ω.