Battery pack and battery charger that charges based on temperature

1. A battery pack comprising:

a connecting portion that is connected to a battery charger;

a battery that is allowed to be charged by the battery charger connected to the connecting portion;

a battery temperature detecting element that detects a temperature of the battery;

an environment temperature detecting element, which is separate from the battery temperature detecting element, that detects an environment temperature around the battery; and

a control circuit that is adapted to periodically detect the environment temperature via the environment temperature detecting element and to control the battery charger to suspend starting of charging the battery or to temporarily discontinue charging the battery when a variation of the environment temperature detected exceeds a predetermined range, when the battery charger is connected to the connecting portion.

2. The battery pack according to claim 1 , wherein the control circuit controls the battery charger to start or re-start charging the battery when the variation of the environment temperature falls within the predetermined range after controlling the battery charger to suspend starting of charging the battery or to temporarily discontinue charging the battery.

3. The battery pack according to claim 1 , wherein the environment temperature detecting element is arranged on a substrate on which the control circuit is mounted or at a position that is farther away from the battery than the substrate is.

4. The battery pack according to claim 1 , further comprising:

an alarm,

wherein, when the control circuit is controlling the battery charger to suspend starting of charging the battery or to temporarily discontinue charging the battery, the control circuit notifies a user of the control of the battery charger by the control circuit by so indicating on the alarm.

5. The battery pack according to claim 1 , further comprising:

a battery temperature detecting element that is attached to the battery and detects a battery temperature; and

an alarm,

wherein the control circuit that is adapted to periodically detect the battery temperature via the battery temperature detecting element, to determine a presence of an abnormality of the environment temperature detecting element when a variation of the battery temperature detected exceeds a predetermined threshold value and the variation of the environment temperature detected falls within the predetermined range, and to notify a user of the presence of the abnormality of the environment temperature detecting element by so indicating on the alarm, when the battery charger is connected to the connecting portion.

6. The battery pack according to claim 5 , wherein the control circuit determines a presence of an abnormality of the battery temperature detecting element when the variation of the environment temperature exceeds the predetermined range and the variation of the battery temperature detected via the battery temperature detecting element is equal to or smaller than the predetermined threshold value and notifies a user of the presence of the abnormality of the battery temperature detecting element via the alarm.

7. The battery pack according to claim 4 , wherein the alarm is provided on the battery charger, and the control circuit controls the alarm to notify via the battery charger.

8. The battery pack according to claim 5 , wherein the alarm is provided on the battery charger, and the control circuit controls the alarm to notify via the battery charger.

9. The battery charger that is connected to the battery pack according to claim 7 to charge the battery, the battery charger comprising:

a charging control unit that switches starting and stopping of charging the battery in accordance with a command from the battery pack,

wherein the charging control unit drives the alarm in accordance with transmitting of a condition of the battery pack from the battery pack and controls the alarm to notify a user of the condition of the battery pack.

10. The battery charger that is connected to the battery pack according to claim 8 to charge the battery, the battery charger comprising:

a charging control unit that switches starting and stopping of charging the battery in accordance with a command from the battery pack,

wherein the charging control unit drives the alarm in accordance with transmitting of a condition of the battery pack from and controls the alarm to notify the condition of the battery pack.