Lithium-ion battery remaining capacity estimation device

摘要

A device that estimates the residual capacity of a lithium ion battery (3) that starts an engine starter (1), includes a control section (30) that calculates resistance values of a cathode and anode of the lithium ion battery based on detected values of a voltage sensor (SN1) and a current sensor (SN2) at the time when a first time has elapsed, and at the time when a second time longer than the first time has elapsed, from startup of the engine starter, and estimates the residual capacity from increases over time in the resistance values. The control section (30) starts the engine starter with the lithium ion battery under conditions under which the startup time of the engine starter will be longer when the last startup time of the engine starter is shorter than the second time or when a predetermined time period has elapsed from the last estimation.