The battery pack is provided with an analog front-end that detects battery voltage, and a micro-controller connected to the analog front-end that accepts analog voltage signals from the analog front-end as input. The micro-controller switches voltage signals input from the analog front-end to determine failure of the analog front-end or the micro-controller.
1. A method of determining failure of a battery pack including (i) a plurality of series connected batteries, (ii) an analog front-end that detects battery voltage, and (iii) a micro-controller connected to the analog front-end, the analog front-end including (i) input switches controlled by the micro-controller, and (ii) a voltage detection circuit that connects with the plurality of batteries via the input switches, the method comprising:
short-circuiting the input-side of the voltage detection circuit by switching, using the micro-controller, the input switches to short circuit the input-side of the voltage detection circuit; and
determining input switch failure,
wherein said determining input switch failure is performed after said short-circuiting the input-side of the voltage detection circuit.
2. A method for determining failure of a battery pack including (i) a plurality of series connected batteries, (ii) an analog front-end that detects battery voltage, and (iii) a micro-controller that accepts analog voltage signals from the analog front-end, the micro-controller being connected to the analog front-end,
wherein the analog front-end includes a plurality of input switches controlled by the micro-controller, and a voltage detection circuit that connects with the plurality of batteries via the input switches,
the method comprising:
switching, using the micro-controller, the input switches to electrically connect positive and negative sides of a battery from among the plurality of batteries to inverting and non-inverting input terminals of the difference amplifier in a reversed polarity state to input the battery voltage to the difference amplifier in the reversed polarity state;
switching, using the micro-controller, the input switches to electrically connect the positive and the negative sides of the battery from among the plurality of batteries to the inverting and non-inverting input terminals of the difference amplifier in an un-reversed polarity state to input the battery voltage to the difference amplifier in the un-reversed polarity state; and
determining failure of the voltage detection circuit,
wherein said determining failure of the voltage detection circuit is performed after (i) said switching the input switching to electrically connect the positive and negative sides of the battery from among the plurality of batteries to the inverting and non-inverting input terminals of the different amplifier in the reversed polarity state and (ii) said switching the input switching to electrically connect the positive and negative sides of the battery from among the plurality of batteries to the inverting and non-inverting input terminals of the different amplifier in the un-reversed polarity state.
3. The method of claim 2 , wherein a standard voltage is input to one of the terminals of the difference amplifier.
4. The method of claim 1 ,
wherein said short-circuiting the input-side of the voltage detection circuit includes detecting an input voltage of the voltage detection circuit with the input-side of the voltage detection circuit short-circuited, and
wherein said determining input switch failure determines that the input switch failure has occurred when the detected input voltage of the voltage detection circuit is not a prescribed value.
5. The method of claim 2 ,
wherein said switching the input switching to electrically connect the positive and negative sides of the battery from among the plurality of batteries to the inverting and non-inverting input terminals of the different amplifier in the reversed polarity state includes detecting an output voltage of the difference amplifier in the reversed polarity state,
wherein said switching the input switching to electrically connect the positive and negative sides of the battery from among the plurality of batteries to the inverting and non-inverting input terminals of the different amplifier in the un-reversed polarity state includes detecting an output voltage of the difference amplifier in the un-reversed polarity state, and
wherein said determining failure of the voltage detection circuit determines that the failure of the voltage detection circuit has occurred when the detected output voltage of the difference amplifier in the reversed polarity state and the detected output voltage of the difference amplified in the un-reversed polarity state deviate from predetermined values, respectively.