To reduce cost by simplifying the structure of a failure determination device of an agitation member.
This failure determination device of an agitation member includes: a coolant 14 exchanging heat with a plurality of cylindrical batteries 121; a storage vessel 11 for storing the plurality of cylindrical batteries 121 and the coolant 14 therein; the agitation member 31 agitating the coolant 14 based on an actuation signal output from a controller 61; and detection sensors 131 and 132 for detecting the temperature difference in the storage vessel 11. The controller 11 determines that the agitation member 31 fails when the temperature difference in the storage vessel 11 is above a preset temperature (for instance, 20C) after the actuation signal is output.
Makoto Ide
Hiroshi Suzawa