Power storage device inspecting method and power storage device manufacturing method
A power storage device inspecting method of inspecting a power storage device for an internal short circuit that includes: detecting an external resistance Re which is generated in an external circuit in a state in which probes of an external power supply are connected to external terminals of the power storage device; applying an initial output voltage VS( 0 ) with which an initial device current IB( 0 ) of a device current IB(t) is zero; applying an output voltage VS(t) from the external power supply to the power storage device; and determining an internal short circuit of the power storage device based on a change with time of the device current IB(t) or a stabilized device current IBs of the power storage device.
1. A power storage device inspecting method of connecting probes of an external power supply to a pair of external terminals of a precharged power storage device to be inspected to form a closed circuit in which a device current IB(t) flows from the external power supply to the power storage device and inspecting the power storage device for an internal short circuit using the device current IB(t) flowing in the closed circuit, the power storage device inspecting method comprising:
an external resistance detecting step of connecting the probes of the external power supply to the pair of external terminals of the power storage device and detecting an external resistance Re which is generated in an external circuit outside the power storage device in the closed circuit;
an initial voltage applying step of applying an initial output voltage VS( 0 ) with which an initial device current IB( 0 ) of the device current IB(t) is zero in a state in which the connection of the probes to the pair of external terminals is maintained;
a voltage applying step of applying an output voltage VS(t) expressed by Equation (1) from the external power supply to the power storage device subsequently to the initial voltage applying step in a state in which the connection of the probes to the pair of external terminals is maintained,
VS ( t ) =VS (0)+( Re−Ro 1) ·IB ( t ) (1)
where a first virtual external resistance Ro1 is a constant satisfying 0<Ro1<Re; and
a short circuit determining step of determining an internal short circuit of the power storage device based on a change with time of the device current IB(t) or a stabilized device current IBs of the power storage device.
2. The power storage device inspecting method according to claim 1 , wherein the voltage applying step includes:
a first voltage applying step of applying the output voltage VS(t) expressed by Equation (1) from the external power supply to the power storage device;
a switching condition determining step of determining whether a predetermined switching condition has been satisfied; and
a second voltage applying step of applying an output voltage VS(t) expressed by Equation (2) from the external power supply to the power storage device subsequently to the first voltage applying step in a state in which the connection of the probes to the pair of external terminals is maintained when the switching condition has been satisfied,
VS ( t ) =VS (0)+( Re−Ro 2) ·IB ( t ) (2)
where a second virtual external resistance Ro2 is a constant satisfying 0<Ro1<Ro2<Re.
3. The power storage device inspecting method according to claim 1 , wherein the external resistance detecting step includes a device voltage measuring step of measuring an open-circuit device voltage VBO of the power storage device, and
wherein the initial voltage applying step includes:
a temporary initial voltage outputting step of outputting an output voltage VS which matches the measured open-circuit device voltage VBO; and
an initial voltage adjusting step of adjusting the output voltage VS to the initial output voltage VS( 0 ) such that the initial device current IB( 0 ) of the device current IB(t) is zero.
4. The power storage device inspecting method according to claim 1 , wherein the power storage device has a flat rectangular shape, and
wherein the power storage device inspecting method is performed under a condition in which the power storage device is pressurized in a thickness direction thereof.
5. A power storage device manufacturing method comprising:
an initial charging step of initially charging an assembled uncharged power storage device to a predetermined state of charge to form the precharged power storage device; and
an internal short circuit inspecting step of inspecting the precharged power storage device for the internal short circuit using the power storage device inspecting method according to claim 1 .