Battery protection circuit, method for protecting battery, power supply device and program

A method for protecting a battery comprising executing steps by a control part, the steps comprising:

• connecting a discharge path to a load of a battery and a power supply path from the battery to the control part;
• discharging the load of the battery;
• cutting off the discharge path to the load of the battery when a voltage value of the battery is equal to or less than a first threshold value;
• cutting off all power supplied to the control part itself when the voltage value of the battery is equal to or less than a second threshold value which is lower than the first threshold value;
• and
• cutting off a charge path to the battery when the voltage value of the battery is equal to or less than the second threshold value.

A protection circuit for a battery, comprising:

• a voltage measuring part configured to measure voltage values of the battery;
• a discharge switch configured to open and close a discharge path to a load for the battery;
• a power switch configured to open and close a power supply path from the battery to a control part;
• and
• a charge switch configured to open and close a charge path to the battery, wherein
• the control part is configured to
• close the discharge switch, the power switch, and the charge switch,
• open the discharge switch in the discharge path to the load for the battery when a voltage value of the battery is equal to or less than a first threshold value,
• open the power switch in the power supply path from the battery to the control part, thereby cutting off all power supplied from the battery to the control part and inhibiting over discharging and heating of the battery when the voltage value of the battery is equal to or less than a second threshold value that is less than the first threshold value and is greater than zero, and
• open the charge switch in the charge path to the battery when the voltage value of the battery is equal to or less than the second threshold value and is greater than zero.