Battery degradation detection device

A battery degradation detection device that detects a degradation state of a battery installed on a vehicle, the battery degradation detection device comprising:

• a flag setting unit that, for each vehicle start, sets a flag indicating a sign of degradation of the battery only when a voltage value of the battery at a start of the vehicle is continuously less than a first predetermined voltage value for a first predetermined period of time or longer;
• a flag storage unit that stores the flag;
• a sign-of-degradation determination unit that determines whether or not the battery shows a sign of degradation on the basis of the number of times the flag has been stored in the past;
• and
• a degradation determination unit that determines whether or not the battery is in a degradation state after it is determined by the sign-of-degradation determination unit that the battery shows a sign of degradation, wherein the degradation determination unit determines the battery is in the degradation state when the voltage value of the battery is continuously less than a second predetermined voltage value, which is less than the first predetermined voltage value, for a second predetermined period of time or longer;
• and
• a display unit that displays a warning of at least one of the sign-of-degradation determination result or the degradation determination result.