Method and apparatus for charging a battery and for determining a voltage of the battery during charging
First Claim
1. A charging device (1) for charging a battery (2), including a power supply (5) and a pulse controller (4) for chopping according to a certain duty cycle (η
- ) a charging current (Ich) taken from said power supply (5) to the battery (2) being charged, characterized in that said charging device (1) further includes a measuring means (6) for measuring, during a pulse (Ion) of said charging current (Ich) and between pulses of said charging current (Ich), a terminal voltage of the battery (2) being charged and a control means (3) for altering the duty cycle (η
) used by said pulse controller (4) on the basis of the measured terminal voltage.
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Accused Products
Abstract
The invention is related to a charging device (1) in which the charging current (Ich) used for charging a battery (2) is chopped according to a certain duty cycle (η). A certain charging voltage reference value (Vch), which equals the real open circuit voltage of the battery charged, is known to the charging device (1). To achieve a correct duty cycle (η), the terminal voltage of the battery is measured during the charging current pulse (Ion) and between the pulses. The open circuit voltage of the battery is calculated on the basis of the measurement results using the formula
V.sub.batt0 =V.sub.min +K*η*(V.sub.max -V.sub.min)
where η is said duty cycle, Vmax represents the voltage between the terminals of said battery (2) during the charging current pulse (Ion), Vmin represents the voltage between the terminals of said battery (2) between the charging current pulses and the coefficient K equals 1 or the ratio of the average of the charging current (Ich) to its peak value. The duty cycle is altered in such a manner that the calculated value (Vbatt0) is brought close to said reference value (Vch).
35 Citations
17 Claims
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1. A charging device (1) for charging a battery (2), including a power supply (5) and a pulse controller (4) for chopping according to a certain duty cycle (η
- ) a charging current (Ich) taken from said power supply (5) to the battery (2) being charged, characterized in that said charging device (1) further includes a measuring means (6) for measuring, during a pulse (Ion) of said charging current (Ich) and between pulses of said charging current (Ich), a terminal voltage of the battery (2) being charged and a control means (3) for altering the duty cycle (η
) used by said pulse controller (4) on the basis of the measured terminal voltage. - View Dependent Claims (2, 3, 4)
- ) a charging current (Ich) taken from said power supply (5) to the battery (2) being charged, characterized in that said charging device (1) further includes a measuring means (6) for measuring, during a pulse (Ion) of said charging current (Ich) and between pulses of said charging current (Ich), a terminal voltage of the battery (2) being charged and a control means (3) for altering the duty cycle (η
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5. A charging device (1) for charging a battery (2), including a power supply (5) and pulse width controller (4) for chopping according to a certain duty cycle (η
- ) the charging current (Ich) taken from said power supply (5) to the battery (2) charged, characterized in that it also includes a measuring means (6) for measuring, during charging, the terminal voltage of the battery (2) charged and a control means (3) for altering the duty cycle (η
) used by said pulse width controller (4) on the basis of the measured terminal voltage, wherein said charging device (1) includes a means (3) for calculating the open circuit voltage (Vbatt0) of the battery (2) charged on the basis of said measurement data (Vmax, Vmin) using the formula
space="preserve" listing-type="equation">V.sub.batt0 =V.sub.min +K*η
*(V.sub.max -V.sub.min)where η
is said duty cycle, Vmax represents the voltage between the terminals of said battery (2) during the charging current pulse (Ion), Vmin represents the voltage between the terminals of said battery (2) between the charging current pulses and the coefficient K equals 1, if said power supply (5) is a DC power supply, and it equals the ratio of the average value of the charging current (Ich) to its peak value during the charging current pulse (Ion), if said power supply (5) is a diode-rectified AC power supply.
- ) the charging current (Ich) taken from said power supply (5) to the battery (2) charged, characterized in that it also includes a measuring means (6) for measuring, during charging, the terminal voltage of the battery (2) charged and a control means (3) for altering the duty cycle (η
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6. A method for charging a battery (2) with a charging device (1), comprising the steps of:
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applying charging current pulses having a selected duty cycle (η
) to the battery (2);measuring a first voltage appearing across terminals of the battery (2) during one of the charging current pulses; measuring a second voltage appearing across the terminals of the battery (2) between a pair of the charging current pulses; and altering the duty cycle (η
) based on the measured first and second voltages. - View Dependent Claims (7, 8, 9, 10, 11, 12)
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13. A method for charging a battery (2) with a charging device (1) where a charging current (Ich) pulsed according to a certain duty cycle (η
- ) is brought to said battery (2), characterized in that in it the terminal voltage of said battery (2) is measured and said duty cycle (η
) is altered on the basis of the measurement result obtained, and wherein the open circuit voltage (Vbatt0) of said battery is calculated on the basis of said terminal voltage measurements using the formula
space="preserve" listing-type="equation">V.sub.batt0 =V.sub.min +K*η
*(V.sub.max -V.sub.min)where η
is said duty cycle, Vmax represents the voltage between the terminals of said battery (2) during the charging current pulse (Ion), Vmin represents the voltage between the terminals of said battery (2) between the charging current pulses and the coefficient K equals 1, if a DC power supply is used in the charging, and it equals the ratio of the average value of the charging current (Ich) to its peak value during the charging current pulse (Ion), if a diode-rectified AC power supply is used in the charging.
- ) is brought to said battery (2), characterized in that in it the terminal voltage of said battery (2) is measured and said duty cycle (η
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14. A charging device (1) for charging a battery (2) that is connected to a load, the charging device (1) including a power supply (5) and a pulse controller (4) for chopping according to a certain duty cycle (η
- ) a charging current (Ich) taken from said power supply (5) to the battery (2) being charged, said charging device (1) further including a measuring means (6) for measuring, during a pulse (Ion) of said charging current (Ich) and between pulses of said charging current (Ich), the terminal voltage of the battery (2), and a control means (3) for altering the duty cycle (η
) used by said pulse controller (4) on the basis of the measured terminal voltage, wherein the charging current (Ich) charges said battery (2) while said battery (2) is connected to said load. - View Dependent Claims (15)
- ) a charging current (Ich) taken from said power supply (5) to the battery (2) being charged, said charging device (1) further including a measuring means (6) for measuring, during a pulse (Ion) of said charging current (Ich) and between pulses of said charging current (Ich), the terminal voltage of the battery (2), and a control means (3) for altering the duty cycle (η
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16. A method for charging a battery (2) with a charging device (1) while the battery (2) is connected to a load, comprising the steps of:
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applying charging current pulses having a selected duty cycle (η
) to the battery (2) while the battery (2) is connected to the load;measuring a first voltage appearing across terminals of the battery (2) during one of the charging current pulses; measuring a second voltage appearing across the terminals of the battery (2) between a pair of the charging current pulses; and altering the duty cycle (η
) based on the measured first and second voltages. - View Dependent Claims (17)
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Specification