METHOD AND APPARATUS FOR ONLINE DETERMINATION OF BATTERY STATE OF CHARGE AND STATE OF HEALTH
First Claim
1. A system for determining a battery'"'"'s state of charge and state of health, the system comprising:
- a measurement section having a voltage sensor, a current sensor and a temperature sensor, the measurement section adapted to take measurements from the battery;
a power supply connected to the battery via a power supply switch;
a load connected to the battery via a load switch; and
a computer adapted to receive the measurements from the measurement section, the computer having a control card adapted to open and close the power supply switch and the load switch, the computer adapted to calculate an open circuit voltage online, without requiring a battery rest time.
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Accused Products
Abstract
An online method and apparatus for determining state of charge (SoC) and state of health (SoH) of batteries on platforms that present dynamic charge and discharge environments is disclosed. A rested open circuit voltage (OCV) may be estimated online using a battery dynamic model along with measured terminal voltage, current and temperature. The SoC and SoH can then be determined from this estimated OCV. The apparatus and methods may estimate SoC and SoH of a battery in a real-time fashion without the need to a) disconnect the battery system from service; b) wait for a predefined rest time; or c) depolarize the battery.
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Citations
18 Claims
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1. A system for determining a battery'"'"'s state of charge and state of health, the system comprising:
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a measurement section having a voltage sensor, a current sensor and a temperature sensor, the measurement section adapted to take measurements from the battery; a power supply connected to the battery via a power supply switch; a load connected to the battery via a load switch; and a computer adapted to receive the measurements from the measurement section, the computer having a control card adapted to open and close the power supply switch and the load switch, the computer adapted to calculate an open circuit voltage online, without requiring a battery rest time. - View Dependent Claims (2, 3, 4, 5)
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6. A method for determining a battery open circuit voltage online without requiring a battery rest time, the method comprising:
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charging or discharging the battery; computing the open circuit voltage using the equation
VOC=VBAT+Δ
VR+Δ
VPwhere VBAT—
Battery terminal voltage, Δ
VR—
Voltage drop due to battery resistance, and Δ
VP—
Voltage drop due to polarization phenomenon; anddetermining the state of charge using the computed open circuit voltage and a battery temperature. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13)
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11. The method of claim 6, further comprising computing Δ
- VR using the equation
Δ
VR=I*Rswhere Rs is a battery internal resistance and I is a current through terminals of the battery.
- VR using the equation
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12. The method of claim 6, further comprising measuring VBAT using a voltage sensing connected across terminals of the battery.
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13. The method of claim 6, further comprising correlating charge or discharge energy with a change in state of charge and extrapolating to get full battery capacity.
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14. A method for determining the state of health of a battery, comprising:
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estimating full capacity of the battery by; charging or discharging the battery; computing the open circuit voltage using the equation
VOC=VBAT+Δ
VR+Δ
VPwhere VBAT—
Battery terminal voltage, Δ
VR—
Voltage drop due to battery resistance, and Δ
VP—
Voltage drop due to polarization phenomenon;determining the state of charge using the computed open circuit voltage and a battery temperature; and correlating charge or discharge energy with a change in state of charge and extrapolating to get full battery capacity; tracking the battery'"'"'s full capacity as a function of time; and determining if the full capacity of the battery has declined a predetermined amount. - View Dependent Claims (15, 16, 17, 18)
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17. The method of claim 14, further comprising computing Δ
- VR using the equation
Δ
VR=I*Rswhere Rs is a battery internal resistance and I is a current through terminals of the battery.
- VR using the equation
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18. The method of claim 14, further comprising measuring VBAT using a voltage sensing connected across terminals of the battery.
Specification