SWITCH FAILURE DIAGNOSIS DEVICE, POWER STORAGE DEVICE, SWITCH FAILURE DIAGNOSIS PROGRAM AND SWITCH FAILURE DIAGNOSIS METHOD

摘要

PROBLEM TO BE SOLVED: To diagnose whether there is a switch failure while avoiding interrupting a current path between an electric apparatus, such as a load or a charger, and a power storage element.SOLUTION: A battery protection device 3 includes two relays 31 and a battery monitoring unit 33, and the battery monitoring unit 33 includes a control section 34. The control section 34 determines whether there is any failure in the relays 31 on the basis of whether an open both ends voltage V3B under an open command signal given to the relays 31 is within a failure determination range. This can determine whether there is any failure in the relays 31 while avoiding interrupting a current path between an electric apparatus and a secondary battery 2.