Power storage unit and solar power generation unit
Disclosed is a power storage unit which can safely operate over a wide temperature range. The power storage unit includes: a power storage device; a heater for heating the power storage device; a temperature sensor for sensing the temperature of the power storage device; and a control circuit configured to inhibit charge of the power storage device when its temperature is lower than a first temperature or higher than a second temperature. The first temperature is exemplified by a temperature which allows the formation of a dendrite over a negative electrode of the power storage device, whereas the second temperature is exemplified by a temperature which causes decomposition of a passivating film formed over a surface of a negative electrode active material.
1. A power storage unit comprising:
a power storage device;
a first transistor;
a second transistor;
a first diode;
a second diode;
a heater; and
a temperature sensor;
wherein:
a positive electrode of the power storage device is electrically connected to a drain of the first transistor and an anode of the first diode;
a negative electrode of the power storage device is electrically connected to a first terminal of the temperature sensor, an anode of the second diode, and a source of the second transistor;
a cathode of the second diode is electrically connected to a drain of the second transistor and a second terminal of the heater;
a gate of the second transistor is electrically connected to a gate of the first transistor; and
a first terminal of the heater is electrically connected to a source of the first transistor and a cathode of the first diode.
2. The power storage unit according to claim 1 ,
wherein the heater is a positive temperature coefficient thermistor.
3. The power storage unit according to claim 2 ,
wherein a Curie temperature of the positive temperature coefficient thermistor is arranged to be a temperature under which a dendrite of lithium is formed by charging of the power storage device.
4. The power storage unit according to claim 3 ,
wherein the temperature is higher than or equal to 0° C. and lower than or equal to 10° C.
5. The power storage unit according to claim 1 ,
wherein the power storage device is a lithium secondary battery.
6. The power storage unit according to claim 1 ,
wherein the temperature sensor is a negative temperature coefficient thermistor.
7. A solar power generation unit including the power storage unit according to claim 1 .