Patent ID: 7825634

Claim:
A charge accumulating system comprising: a nonaqueous electrolyte battery unit including a nonaqueous electrolyte containing an ionic liquid, a negative electrode and a positive electrode; a temperature detector which detects an ambient temperature of the nonaqueous electrolyte battery unit; first control means for lowering a maximum battery voltage E max of the nonaqueous electrolyte battery unit when the detected temperature T from the temperature detector exceeds a standard ambient temperature T std , the maximum battery voltage being controlled according to the following formulas: E max =E std −α( T−T std ) T std ≦T≦150 20≦T std ≦30 0.001≦α≦0.004 wherein E max denotes a maximum battery voltage (V); E std denotes a standard maximum battery voltage (V); T denotes a detected temperature (° C.); T std denotes a standard ambient temperature (° C.); and α denotes a coefficient; and second control means for controlling a maximum charging amount Q max of the nonaqueous electrolyte battery unit at a constant level when the battery temperature is below the standard ambient temperature T std and lowering the maximum charging amount when the detected temperature T from the temperature detector exceeds the standard ambient temperature T std , wherein the maximum charging amount Q max is controlled according to the following formulas: Q max =Q std {1−β( T−T std )} T std ≦T≦150 20≦T std ≦30 0≦β≦0.001 where Q max denotes a maximum charging amount (Ah); Q std denotes a standard maximum charging amount (Ah); and β denotes a coefficient.