System for displaying residual capacity of a battery

Claim 1

A system for displaying the residual capacity of a secondary battery, comprising: a current detection resistor (2) for converting a charging current and a discharge current of said secondary battery (1) into very small voltages respectively; charging and discharge current detection means (3) composed of a charging side operational amplifier (31) and a discharge side operational amplifier (32) for amplifying the very small voltages appearing across said current detection resistor (2) respectively and outputting the resultant signals respectively; voltage drop detection means (4) for detecting the situation where the voltage of said secondary battery has dropped to a level lower than a predetermined setting; temperature detection means (5) for detecting the ambient temperature of said secondary battery and outputting the resultant signal; electrical quantity computation means (6) receiving the charging current detection output signal and the discharge current detection output signal of said charging and discharge current detection means (3) together with the output signal of said temperature detection means (5) as its inputs for deciding whether the operation mode is the charging mode, the discharge mode or the stand-by mode and computing the quantity of electricity in that mode; charging completion detection means (7) setting its output signal when completion of charging said secondary battery is detected, but resetting its output signal when charging said secondary battery is started; discharged electrical quantity integration means (8) for integrating the discharged quantity of electricity at time intervals of a predetermined period when the output signal of said charging completion detection means (7) is in the set state and the output signal of said electrical quantity computation means (6) indicates the discharge mode, but, when the output signal of said charging completion detection means (7) is in the reset state, nullifying the integrated value irrespective of the output signal of said electrical quantity computation means (6); capacity memory means (9) for storing the capacity value integrated by said discharged electrical quantity integration means (8) as a newest battery capacity when the output signal of said charging completion detection means (7) is in the set state and the voltage drop signal is first outputted from said voltage drop detection means (4) after the charging is started; electrical quantity integration means (10) for integrating, at time intervals of the predetermined period, the quantity of electricity by addition when the output signal of said electrical quantity computation means (6) represents the electrical quantity in the charging mode, but by subtraction when the output signal of said electrical quantity computation means (6) represents the electrical quantity in the discharge mode, thereby determining the value of the residual capacity on the basis of the ratio of the integrated value of the quantity of electricity to the capacity value stored in said capacity memory means (9), said electrical quantity integration means (10) setting the integrated value of the quantity of electricity to correspond to the value of the residual capacity at the predetermined voltage level when the voltage drop signal is first outputted from said voltage drop detection means (4) after the charging is started, but setting the integrated value of the quantity of electricity to correspond to the residual capacity of 100 % when the output signal of said charging completion detection means (7) is in the set state as a result of the charging; and display means (11) for displaying the residual capacity stepwise on the basis of the value of the residual capacity determined by said electrical quantity integration means (10).

Claim 4

A system for displaying the residual capacity of a secondary battery, comprising: a current detection resistor (2) for converting a charging current and a discharge current of said secondary battery (1) into very small voltages respectively; charging and discharge current detection means (3) composed of a charging side operational amplifier (31) and a discharge side operational amplifier (32) for amplifying the very small voltages appearing across said current detection resistor (2) respectively and outputting the resultant signals respectively; residual capacity alarm means (41) receiving the terminal voltage of said secondary battery and the discharge current output signal of said charging and discharge current detection means (3) as its inputs and correcting to lower the battery voltage detection level in proportion to an increase in the discharge current, thereby generating an alarm signal irrespective of the value of the discharge current when a predetermined setting of the residual capacity of said secondary battery is reached; temperature detection means (5) for detecting the ambient temperature of said secondary battery and outputting the resultant signal; electrical quantity computation means (6) receiving the charging current detection output signal and the discharge current detection output signal of said charging and discharge current detection means (3) together with the output signal of said temperature detection means (5) as its inputs for deciding whether the operation mode is the charging mode, the discharge mode or the stand-by mode and computing the quantity of electricity in that mode; charging completion detection means (7) setting its output signal when completion of charging said secondary battery is detected, but resetting its output signal when charging said secondary battery is started; discharged electrical quantity integration means (8) for integrating the discharged quantity of electricity at time intervals of a predetermined period when the output signal of said charging completion detection means (7) is in the set state and the output signal of said electrical quantity computation means (6) indicates the discharge mode, but, when the output signal of said charging completion detection means (7) is in the reset state, nullifying the integrated value irrespective of the output signal of said electrical quantity computation means (6); capacity memory means (9) for storing a value obtained by dividing the value of the electrical quantity integrated by said discharged electrical quantity integration means (8) by a factor determined by a predetermined residual capacity alarm level of said residual capacity alarm means (41) {which factor is (1 - 0.1 = 0.9) when said predetermined residual capacity alarm level is 10%} as a newest battery capacity when the output signal of said charging completion detection means (7) is in the set state and the alarm signal is first generated from said residual capacity alarm means (41) after the charging is started; electrical quantity integration means (10) for integrating, at time intervals of the predetermined period, the quantity of electricity by addition when the output signal of said electrical quantity computation means (6) represents the electrical quantity in the charging mode, but by subtraction when the output signal of said electrical quantity computation means (6) represents the electrical quantity in the discharge mode, thereby determining the value of the residual capacity on the basis of the ratio of the integrated value of the quantity of electricity to the capacity value stored in said capacity memory means (9), said electrical quantity integration means (10) setting the integrated value of the quantity of electricity to correspond to the value of the predetermined residual capacity when the alarm signal is first generated from said residual capacity alarm means (41) after the charging is started, but setting the integrated value of the quantity of electricity to correspond to the residual capacity of 100% when the output signal of said charging completion detection means (7) is in the set state as a result of the charging; and display means (11) for displaying stepwise the residual capacity on the basis of the value of the residual capacity determined by said electrical quantity integration means (10).

Claim 6

A system for displaying the residual capacity of a secondary battery, comprising: a current detection resistor (2) for converting a charging current and a discharge current of said secondary battery (1) into very small voltages respectively; charging and discharge current detection means (3) composed of a charging side operational amplifier (31) and a discharge side operational amplifier (32) for amplifying the very small voltages appearing across said current detection resistor (2) respectively and outputting the resultant signals respectively; residual capacity alarm means (41) receiving the terminal voltage of said secondary battery and the discharge current output signal of said charging and discharge current detection means (3) as its inputs and correcting to lower the battery voltage detection level in proportion to an increase in the discharge current, thereby generating an alarm signal irrespective of the value of the discharge current when a predetermined setting of the residual capacity of said secondary battery is reached; temperature detection means (5) for detecting the ambient temperature of said secondary battery and outputting the resultant signal; electrical quantity computation means (6) receiving the charging current output signal and the discharge current output signal of said charging and discharge current detection means (3) together with the output signal of said temperature detection means (5) as its inputs for deciding whether the operation mode is the charging mode, the discharge mode or the stand-by mode, and, when the detected mode is the discharge mode, multiplying the discharge current output value by a predetermined period to compute the discharged quantity of electricity and then multiplying the computed quantity of electricity by the discharge efficiency determined by both the discharge current output value and the ambient temperature of said secondary battery to compute the final quantity of electricity, while when the detected mode is the stand-by mode, computing the quantity of electricity by selecting suitable temperature data meeting the detected temperature from among those data prepared beforehand for each of the individual ambient temperatures and representing both the self-discharge quantity of electricity of said secondary battery and the quantity of electrical consumption by said battery residual capacity displaying system; charging completion detection means (7) setting its output signal when completion of charging said secondary battery is detected, but resetting its output signal when charging said secondary battery is started; discharged electrical quantity integration means (8) for integrating the quantity of electricity discharged from said electrical quantity computation means (6) at time intervals of said predetermined period when the output signal of said charging completion detection means (7) is in the set state, but nullifying the integrated value when the output signal of said charging completion detection means (7) is in the reset state; capacity memory means (9) for storing a value obtained by dividing the value of the electrical quantity integrated by said discharged electrical quantity integration means (8) by a factor determined by a predetermined residual capacity alarm level of said residual capacity alarm means (41) {which factor is (1 - 0.1 = 0.9) when said predetermined residual capacity alarm level is 10%} as a newest battery capacity when the output signal of said charging completion detection means (7) is in the set state and the alarm signal is first generated from said residual capacity alarm means (41) after the charging is started; capacity rating memory means (42) for storing the rated capacity of said secondary battery; capacity comparison means (14) receiving the capacity value stored in said capacity memory means (9) and the capacity value stored in said capacity rating memory means (42) as its inputs to determine the degree of battery deterioration on the basis of the ratio of the capacity value stored in said capacity memory means (9) to the capacity value stored in said capacity rating memory means (42); and display means (11) for displaying stepwise the degree of battery deterioration on the basis of the value of the battery deterioration determined by said capacity comparison means (14).