Abnormality determination system for secondary battery

An abnormality determination system may include a secondary battery that includes a battery case including a positive terminal and a negative terminal, a switch unit that connects electrically the positive terminal to the battery case based on a first controls signal, the switch unit breaking electrically a connection between the positive terminal and the battery case based on a second control signal, a voltage measurement unit that measures a voltage of the battery case, and a determination unit that determines an abnormality of the secondary battery based on the voltage.