Overdischarge preventing circuit apparatus for a nonawueous electrolyte secondary battery, overdischarge preventing circuit apparatus for a battery pack, secondary battery overdischarge preventing method and overdischarge preventing method for a battery pack
AssigneeKabushiki Kaisha Toshiba
InventorsYuji Satoh, Motoya Kanda, Takashi Kishi
Life of this patent
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Abstract
An overdischarge preventing circuit apparatus according to this invention is an overdischarge preventing circuit apparatus for a nonaqueous electrolyte secondary battery, including a discharge control mechanism which controls discharge of the nonaqueous electrolyte secondary battery when a surface temperature of the nonaqueous electrolyte secondary battery exceeds a discharge control temperature T1 (° C.) represented by T1=T0+QA (1) where T0 is an ambient temperature (° C.), Q is 8 (° C./C), and A is a discharge rate (C).
Claims19
An overdischarge preventing circuit apparatus for a nonaqueous electrolyte secondary battery, comprising:
- a discharge control mechanism which controls discharge of the nonaqueous electrolyte secondary battery when a surface temperature of the nonaqueous electrolyte secondary battery exceeds a discharge control temperature T1 (° C.) represented by
- T1=T0+QA (1)
- where T0 is an ambient temperature in a range of 0 to 60° C., Q is 8 (° C./C), and A is a discharge rate (C) of the nonaqueous electrolyte secondary battery in a case where a current required for discharging a nominal capacity of the nonaqueous electrolyte secondary battery in one hour is 1C, and is within a range of 4C to 7C.
An overdischarge preventing circuit apparatus for a battery pack including a battery in which units each obtained by connecting nonaqueous electrolyte single cells in parallel are connected in series, comprising:
- a discharge control mechanism which, when a surface temperature of the battery exceeds a discharge control temperature T1 (° C.) represented by equation (1) below, stops discharge of the battery pack if a voltage of the battery is not more than a discharge stop voltage Va (V) represented by equation (2) below or a voltage of the single cell is less than 3 V, and lowers a discharge rate of the battery pack if the voltage of the battery is higher than the discharge stop voltage Va (V) and the voltage of the single cell is not less than 3 V:
- T1=T0+QA (1)
- where T0 is an ambient temperature (° C.), Q is 8 (° C./C), and A is a discharge rate (C);
- and
- Va=n×3 (V) (2)
- where n is the number of series-connected units in the battery.
A secondary battery overdischarge preventing method comprising controlling discharge of a nonaqueous electrolyte secondary battery when a surface temperature of the nonaqueous electrolyte secondary battery exceeds a discharge control temperature T1 (° C.) represented by
- T1=T0+QA (1)
- where T0 is an ambient temperature (° C.), Q is 8 (° C./C), and A is a discharge rate (C) of the nonaqueous electrolyte secondary battery in a case where a current required for discharging a nominal capacity of the nonaqueous electrolyte secondary battery in one hour is 1C, and is within a range of 4C to 7C.
An overdischarge preventing method for a battery pack including a battery in which units each obtained by connecting nonaqueous electrolyte single cells in parallel are connected in series, comprising:
- when a surface temperature of the battery exceeds a discharge control temperature T1 (° C.) represented by equation (1) below, stopping discharge of the battery pack if a voltage of the battery is not more than a discharge stop voltage Va (V) represented by equation (2) below or a voltage of the single cell is less than 3 V, and lowering a discharge rate of the battery pack if the voltage of the battery is higher than the discharge stop voltage Va (V) and the voltage of the single cell is not less than 3 V:
- T1=T0+QA (1)
- where T0 is an ambient temperature (° C.), Q is 8 (° C./C), and A is a discharge rate (C);
- and
- Va=n×3 (V) (2)
- where n is the number of series-connected units in the battery.
Dependencies are inferred from the claim text.