Method and apparatus for estimating SOC of a battery
원문보기
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
G01R-031/36
G06F-011/30
출원번호
US-0887644
(2010-09-22)
등록번호
US-8452556
(2013-05-28)
발명자
/ 주소
Zhang, Yilu
Shin, Kwang-Keun
Tang, Xidong
Salman, Mutasim A.
출원인 / 주소
GM Global Technology Operations LLC
인용정보
피인용 횟수 :
0인용 특허 :
2
초록▼
A method of determining a state-of-charge for a battery is provided. A startup state-of-charge of the battery is determined as a function of a present open circuit voltage measurement for a present ignition startup, at least one open circuit voltage observation of a previous ignition startup, and a
A method of determining a state-of-charge for a battery is provided. A startup state-of-charge of the battery is determined as a function of a present open circuit voltage measurement for a present ignition startup, at least one open circuit voltage observation of a previous ignition startup, and a current draw integration over a time period from a previous ignition startup event to a present ignition startup event. A run state-of-charge change of the battery is determined for an ignition key-on operation. The run state-of-charge change comprises a difference between the present open circuit voltage measurement and the at least one previous open circuit voltage observation, and is determined in response to of a current draw integration over a respective period of time. The state-of-charge of the battery is calculated based on a function of the startup state-of-charge and the run state-of-charge change of the battery.
대표청구항▼
1. A method of determining a state-of-charge for a battery, the method comprising the steps of: measuring open circuit voltages of a vehicle battery during ignition startups by a voltmeter;determining a startup state-of-charge of the battery by a control module as a function of a present open circui
1. A method of determining a state-of-charge for a battery, the method comprising the steps of: measuring open circuit voltages of a vehicle battery during ignition startups by a voltmeter;determining a startup state-of-charge of the battery by a control module as a function of a present open circuit voltage measurement for a present ignition startup, at least one open circuit voltage observation of a previous ignition startup, and a current draw integration over a time period from a previous ignition startup event to a present ignition startup event;determining a run state-of-charge change of the battery by the control module for an ignition key-on operation, the run state-of-charge change comprising a difference between the present open circuit voltage measurement and the at least one previous open circuit voltage observation, and determined in response to a current draw integration over a respective period of time; andcalculating the state-of-charge of the battery by the control module based on a function of the startup state-of-charge and the run state-of-charge change of the battery. 2. The method of claim 1 wherein the state-of-charge for a battery is represented by the following formula: Soc=SOCstartup+SOCrunning=f(Voc(0),T)+θ∫Idt where f(Voc(0),T) is the startup state-of-charge and is a function of the open circuit voltage and temperature, and θ∫Idt is a run state-of-charge change and is a function of a battery parameter and the current draw integration over the respective period of time. 3. The method of claim 2 wherein the startup state-of-charge is derived from an open circuit voltage estimation based on the following formula: V^oc(tk)=λ{V^(tk-1)+θ^∫tk-1tkiⅆt}+(1-λ)Voc(tk)where Voc(t) is the present open circuit voltage measurement at the kth ignition start, {circumflex over (V)}oc(tk−1) is the previous open circuit voltage observation, {circumflex over (θ)} is the battery parameter, I is a current draw from the battery, and λ is an adjustment factor. 4. The method of claim 3 wherein the adjustment factor is represented by the following formula: λ=e−toff(tk)/τ where toff is an elapsed time between an ignition key-on operation and an ignition key-off operation, tk is a time the ignition key is turned on at the kth ignition interval, and τ is a time constant. 5. The method of claim 3 wherein the battery parameter θ is a function of a previous battery parameter observation and a present estimated battery parameter. 6. The method of claim 5 wherein the battery parameter θ is represented by the following formula: θ^k=λθθ^k-1+(1-λθ)Voc(tk)-V^oc(tk-1)∫tk-1tkIⅆtwhere λθ is an adjustment factor for the battery parameter, λθ{circumflex over (θ)}k-1 is a previous battery parameter observation, and Voc(tk)-V^oc(tk-1)∫tk-1tkIⅆt is a present battery parameter observation. 7. The method of claim 6 wherein the adjustment factor for the battery parameter is a function of a time that an ignition key is off, and wherein the adjustment factor is determined by the following formula: λ=e−toff(tk)/τθ. 8. The method of claim 6 wherein the present open circuit voltage measurement, the previous open circuit voltage observation, and the battery parameter are normalized at a respective temperature. 9. The method of claim 8 wherein the open circuit voltages for the startup state-of-charge and the run state-of-charge change are normalized at a respective temperature. 10. The method of claim 9 wherein a normalized open circuit voltage for the state-of-charge of the battery is determined as a function of the open circuit voltage determined for the startup state-of-charge at the respective temperature, and a function of the battery parameter and current integration for the run state-of-charge change at the respective temperature. 11. The method of claim 10 wherein the normalized open circuit voltage for the state-of-charge of the battery is converted back to an open circuit voltage at a current temperature. 12. The method of claim 11 wherein the state-of-charge of the battery is determined as a function of the open circuit voltage at the current temperature. 13. The method of claim 1 wherein the state of charge of the battery is displayed to user of the vehicle via a display device. 14. The method of claim 1 wherein a representation of the state of charge of the battery is displayed to user of the vehicle via a display device. 15. A system for determining a state-of-charge of a battery comprising: a battery;at least one component for drawing power from the battery;a voltmeter for measuring an open circuit voltage of the battery at ignition start sequences;a current sensor for sensing current drawn from the battery; anda control module for determining a state-of-charge of a battery as a function of the startup state-of-charge and the run state-of-charge change of the battery, the startup state-of-charge being determined at a time of an ignition startup event, the startup state-of-charge being a function of a present open circuit voltage measurement for a present ignition startup, at least one previous open circuit voltage observation, and a current integration over time period from a previous ignition event to a present ignition event, the run state-of-charge change comprising at a time during an ignition on operation, the run state-of-charge change being estimated as a difference between the present open circuit voltage measurement and at least one previous open circuit voltage observation determined in response to current integration over a respective period of time. 16. The system of claim 15 wherein the control module determines the startup state-of-charge from an estimated open circuit voltage based on the following formula: V^oc(tk)=λ{V^(tk-1)+θ^∫tk-1tkiⅆt}+(1-λ)Voc(tk)where Voc(t) is the present open circuit voltage measurement at the kth ignition start, {circumflex over (V)}oc(tk-1) is the previous open circuit voltage observation, {circumflex over (θ)} is a battery parameter, I is a current draw from the battery, and λ is an adjustment factor. 17. The system of claim 16 wherein the control module determines the adjustment factor based on the following formula: λ=e−toff(tk)/τwhere toff is an elapsed time between an ignition key-on operation and an ignition key-off operation, tk is a time the ignition key is turned on at the kth ignition interval, and τ is a time constant. 18. The system of claim 17 wherein the control module determines the battery parameter based on the following formula: θ^k=λθθ^k-1+(1-λθ)Voc(tk)-V^oc(tk-1)∫tk-1tkIⅆt where λθ is an adjustment factor for the battery parameter, λθ{circumflex over (θ)}k-1 is a previous battery parameter observation, and Voc(tk)-V^oc(tk-1)∫tk-1tkIⅆt is a present battery parameter observation. 19. The system of claim 15 wherein the control module determines the adjustment factor for the battery parameter based on the following formula: λ=e−toff(tk)/τθ. 20. The system of claim 15 further comprising a display for identifying the state of charge of the battery to a user of the vehicle.
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