Patent ID: 7767354

Claim:
A temperature controlling apparatus for batteries, comprising: a plurality of batteries connected to each other, a cooling fan for sending cooling air to the plurality of batteries connected to each other, a plurality of temperature measuring means for measuring a temperature of each of the plurality of batteries; a temperature difference calculating means for calculating a temperature difference among the plurality of batteries; a controlling means for setting and controlling electric current supplied to the cooling fan, an electric current measuring means for measuring current which is charged to the plurality of batteries or discharged from the plurality of batteries, said measured current being used to calculate an estimated heat generation, wherein said controlling means for setting and controlling electric current includes: a first setting means for setting a first value of the electric current supplied to the cooling fan such that if the detected temperature of the battery having the highest temperature exceeds a predetermined temperature value or if the estimated heat generation of the battery having the highest temperature exceeds a predetermined heat generation value, then the first value is set as a function of the detected temperature of the battery having the highest temperature and the estimated heat generation of the battery having the highest temperature in a three-dimensional map, a second setting means for setting a second value of the electric current supplied to the cooling fan according to the temperature difference between the highest temperature and the lowest temperature among the plurality of batteries; and a comparison controlling means for choosing a larger one of the first value and the second value, and thereby controlling the cooling fan.