Battery pack and remaining battery power calculation method
First Claim
1. A battery pack comprising a battery cell and being capable of calculating a remaining battery power according to a number of charge/discharge cycles and temperature during operation, comprising:
- temperature measurement means for measuring temperature of said battery cell;
charge/discharge cycle counting means for counting a number of charge/discharge cycles;
correction value storage means for storing correction values as a function of a range of the number of charge/discharge cycles and a range in temperature, each correction value corresponding to one range of charge/discharge cycles and one range in temperature; and
remaining power calculation means for specifying one correction value by searching the correction value storage means based on the measured temperature and the counted number of charge/discharge cycles, and calculating the remaining battery power corresponding to the specified correction value,wherein at a low temperature range, the correction values change the remaining battery power of the battery pack on a stepwise basis every predetermined number of cycles up to a specified number of cycles and thereafter linearly changes the remaining battery power every predetermined number of cycles.
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Abstract
To reduce calculation errors of remaining batter power so as to take into account capacity diminutions due to cycle degradation and temperature, a remaining power calculation device specifies a temperature correction value for calculation of remaining battery power corresponding to temperature, from among temperature correction values changed every predetermined number of charge/discharge cycles stored in a correction value storage device, on the basis of a temperature of a battery cell measured by a temperature measurement device and the number of charge/discharge cycles counted by a charge/discharge counting device, and calculates remaining battery power corresponding to the specified temperature correction value. Temperature correction values changed every predetermined number of charge/discharge cycles are used instead of setting different temperature correction values for all charge/discharge cycles, whereby correction of remaining battery power based on cycle degradation and temperature is performed with a small number of parameters.
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Citations
19 Claims
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1. A battery pack comprising a battery cell and being capable of calculating a remaining battery power according to a number of charge/discharge cycles and temperature during operation, comprising:
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temperature measurement means for measuring temperature of said battery cell; charge/discharge cycle counting means for counting a number of charge/discharge cycles; correction value storage means for storing correction values as a function of a range of the number of charge/discharge cycles and a range in temperature, each correction value corresponding to one range of charge/discharge cycles and one range in temperature; and remaining power calculation means for specifying one correction value by searching the correction value storage means based on the measured temperature and the counted number of charge/discharge cycles, and calculating the remaining battery power corresponding to the specified correction value, wherein at a low temperature range, the correction values change the remaining battery power of the battery pack on a stepwise basis every predetermined number of cycles up to a specified number of cycles and thereafter linearly changes the remaining battery power every predetermined number of cycles. - View Dependent Claims (2, 3, 5, 6, 7, 8, 9, 10, 11)
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4. A remaining battery power calculating method of calculating a remaining battery power according to a number of charge/discharge cycles and temperature during operation, comprising the steps of:
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measuring temperature of a battery cell; specifying a temperature correction value for calculating a remaining battery power corresponding to the measured temperature, wherein said value is derived from at least one of a plurality of stored values, each stored value corresponding to at least one temperature value and to a range of charge/discharge cycles, each range comprising a plurality of numbers of charge/discharge cycles, said derived value being selected based on the measured temperature and the current number of charge/discharge cycles; and calculating the remaining battery power corresponding to the temperature correction value, wherein at a low temperature range, the correction values change the remaining battery power of the battery pack on a stepwise basis every predetermined number of cycles up to a specified number of cycles linearly changes the remaining battery power every predetermined number of cycles. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
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Specification