Source: http://www.google.com/patents/US7528575?ie=ISO-8859-1
Timestamp: 2014-03-17 18:29:06
Document Index: 699145072

Matched Legal Cases: ['art 103', 'art 110', 'art 110', 'art 111', 'art 112', 'art 112', 'art 104', 'art 113', 'art 112', 'art 109', 'art 114', 'art 114', 'art 104']

Patent US7528575 - Method and apparatus for correcting voltage of secondary battery, and method ... - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsThe present invention provides an apparatus for correcting a voltage of a secondary battery, wherein accuracy in measurement of battery voltages between battery blocks in different voltage measurement systems. In a battery ECU (101), the following components are disposed: a first voltage measuring part...http://www.google.com/patents/US7528575?utm_source=gb-gplus-sharePatent US7528575 - Method and apparatus for correcting voltage of secondary battery, and method and apparatus for estimating state of charge of secondary batteryAdvanced Patent SearchPublication numberUS7528575 B2Publication typeGrantApplication numberUS 10/567,799Publication dateMay 5, 2009Filing dateApr 19, 2004Priority dateAug 14, 2003Fee statusPaidAlso published asCN1836172A, CN100547427C, EP1679523A1, EP1679523A4, US20060273802, WO2005017545A1Publication number10567799, 567799, US 7528575 B2, US 7528575B2, US-B2-7528575, US7528575 B2, US7528575B2InventorsYusai Murakami, Norito YamabeOriginal AssigneePanasonic Ev Energy Co., Ltd.Export CitationBiBTeX, EndNote, RefManPatent Citations (7), Referenced by (4), Classifications (10), Legal Events (2) External Links: USPTO, USPTO Assignment, EspacenetMethod and apparatus for correcting voltage of secondary battery, and method and apparatus for estimating state of charge of secondary batteryUS 7528575 B2Abstract The present invention provides an apparatus for correcting a voltage of a secondary battery, wherein accuracy in measurement of battery voltages between battery blocks in different voltage measurement systems. In a battery ECU (101), the following components are disposed: a first voltage measuring part (102-1), a second voltage measuring part (102-2), a third voltage measuring part (102-3) and a fourth voltage measuring part (102-4) which are disposed in different voltage measurement systems so as to measure voltages of plural battery blocks; a representative voltage calculating part (105) for calculating representative voltages from battery voltages measured by the first to fourth voltage measuring parts; a voltage correction value calculating part (107) for calculating voltage correction values on the basis of the respective representative voltages; and a correction value reflecting part (109) for adding the voltage correction values to measured voltages of battery blocks in the respective corresponding voltage measurement systems.
calculating representative voltages from battery voltages measured in the respective voltage measurement systems in an electronic control unit;
calculating voltage correction values on the basis of the calculated representative voltages in the electronic control unit;
correcting the measured voltages of the secondary batteries in the voltage measurement systems, on the basis of the voltage correction values; and
controlling a state of charge of the battery system using the corrected measured voltages.
correcting the measured voltages of the secondary batteries in each of the voltage measurement systems, on the basis of the voltage correction values;
calculating state of charge of the secondary batteries on the basis of the battery voltages obtained through a step of correcting the measured voltages; and
controlling the state of charge of the secondary battery using at least the calculated state of charge.
a state of charge calculating part for calculating state of charge of the secondary batteries on the basis of battery voltages obtained by the correction value reflecting part. Description
TECHNICAL FIELD The present invention relates to a method for measuring the voltage of a secondary battery such as a nickel-metal hydride (Ni-MH) battery to be mounted as a power source for a motor and a driving source for various loads, in a pure electric vehicle (PEV), a hybrid electric vehicle (HEV), and the like, and for estimating State of Charge (SOC) on the basis of the thus measured voltage.
BACKGROUND ART Conventionally, in an HEV, the voltage, current, temperature and the like of a secondary battery are detected, and the state of charge (hereinafter, abbreviated as an �SOC�) of the secondary battery is estimated by computation, whereby an SOC is controlled so as to optimize the fuel consumption efficiency of a vehicle. In order to control the SOC exactly, it is necessary to estimate exactly the SOC of the secondary battery being charged/discharged.
Conventionally, the following methods have been known for estimating SOC from a battery voltage. First, several sets of data for voltage V and a charging/discharging current I are acquired and stored in a predetermined period of time, from which a primary approximate line (a voltage (V)-current (I) approximate line) is calculated, and a V section of the V-I approximate line is calculated as a battery voltage (Voc) (no-load voltage). In addition, an accumulated value ∫I of the current I is calculated, and a polarization voltage Vp of the battery is obtained from a function including temperature T, battery voltage Voc, and current accumulated value ∫I, as variables. Electromotive force E is obtained by subtracting the polarization voltage Vp from the battery voltage Voc. Next, by referring to a previously-provided electromotive force�SOC characteristic, SOC is estimated from the thus obtained electromotive force E.
While the voltage random error imposes fewer influences on the SOC estimation errors between the battery blocks, the voltage offset error occurs easily in the voltage between battery blocks whose voltage measurement systems are different from each other. When using a highly-accurate voltage sensor or a voltage detection circuit system for securing voltage offset error of not more than several tens of milli-volts, the cost will be raised. For this reason, a low-cost product with poor accuracy is used reluctantly in development of an inexpensive product. This will increase the estimation error of SOC between electrode blocks.
DISCLOSURE OF INVENTION Therefore, with the foregoing in mind, it is an object of the present invention to provide a method and an apparatus for correcting a voltage of a secondary battery where the accuracy in measurement of the battery voltage between battery blocks corresponding to different voltage measurement systems is improved, thereby providing a method and an apparatus for estimating SOC accurately even when the measured battery voltage includes an offset error.
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a block diagram showing an exemplary configuration of a battery pack apparatus including a voltage correction apparatus and a state of charge estimation apparatus for a secondary battery according to one embodiment of the present invention.
DESCRIPTION OF THE INVENTION Hereinafter, preferred embodiments of the present invention will be described by referring to the attached figures.
The current data I from the current measuring part 103 is inputted to the accumulated capacity calculating part 110 so that an accumulated capacity Q in a predetermined period of time is calculated. The accumulated capacity Q calculated by the accumulated capacity calculating part 110 is inputted to a capacity change calculating part 111 so that a variation (capacity change) ΔQ of the accumulated capacity Q in a predetermined period of time (for example, one minute) is obtained. The capacity change ≢Q is inputted to a polarization voltage calculating part 112. The polarization voltage calculating part 112, calculates a polarization voltage Vpol on the basis of the temperature data T measured at the temperature measuring part 104, with reference to a characteristic curve or formula for obtaining the polarization voltage Vpol based on the capacity charge ΔQ and temperature as a parameter, which has been stored in a look-up table (LUT) 1121. For the case of use in a HEV for example, a characteristic curve that can correspond to a temperature range from −30� C. to +60� C. is stored in the LUT1121 as look-up data.
Next, as mentioned above, the electromotive force calculating part 113 calculates an electromotive force Veq (epuilibrium potential) by subtracting the polarization voltage Vpol obtained by the polarization voltage calculating part 112 from the correction voltage data Vc(i) obtained by the correction value reflecting part 109. The thus calculated electromotive force Veq is inputted to a state of charge calculating part 114. The state of charge calculating part 114 calculates a state of charge (SOC) for each battery block on the basis of temperature data T measured at the temperature measuring part 104, with reference to a characteristic curve or formula for obtaining the electromotive force Veq based on the state of charge (SOC) and temperature as a parameter, which has been stored in a look-up table (LUT) 1141. For the case of use in a HEV for example, a characteristic curve that can correspond to a temperature range from −30� C. to +60� C. is stored as look-up data in the LUT1141.
Next, in an electromotive force calculation step S210, a polarization voltage Vpol that is calculated in a polarization voltage calculation step S209 is subtracted from the correction voltage data Vc(i) calculated in the correction value reflection step S206 so as to calculate an electromotive force Veq. Then, in a state of charge calculation step S211, SOC will be calculated from the electromotive force Veq calculated in the electromotive force calculation step S210 on the basis of a look-up table where an electromotive force Veq�SOC characteristic data with temperature data T being a parameter have been stored.
As mentioned above, according to this embodiment, it will be possible to correct a voltage difference (offset error) that occurs between the odd-number battery blocks 10-(2 i-1) (i=1-10) and the even-number battery blocks 10-2 i (i=1-10) in the battery pack 10. Thereby, reliability in battery control can be improved by using a battery voltage with an improved measurement accuracy for estimation of the SOC. Particularly, this provides some advantages, for example, that SOC estimation errors between battery blocks can be reduced to improve the SOC estimation accuracy, and also the equal charging period can be found precisely.
INDUSTRIAL APPLICABILITY A method and an apparatus for correcting a voltage of a secondary battery according to the present invention improves accuracy in measurement of battery voltages between battery blocks corresponding to different voltage measurement systems. Thereby, SOC can be estimated accurately even when the measured battery voltage includes an offset error. And thus, the present invention can be applied preferably electric vehicles such as a pure electric vehicle (PEV), a hybrid electric vehicle (HEV), and a hybrid vehicle having a fuel cell and a secondary battery; and a power source apparatus equipped with a backup power source.
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS20030097225 *Oct 31, 2002May 22, 2003Ishishita TeruoState of charge calculation device and state of charge calculation methodUS20040095143 *Aug 12, 2003May 20, 2004Vb Autobatterie GmbhMethod for determining the amount of charge which can be drawn from a storage battery and a monitoring device for a storage batteryUS20050017685 *Jun 1, 2004Jan 27, 2005Glynne ReesBattery life monitor and battery state of charge monitorUS20050189916 *Jan 15, 2004Sep 1, 2005Constantin BucurPower management circuitEP1679523A1 *Apr 19, 2004Jul 12, 2006Panasonic EV Energy Co., Ltd.Secondary battery voltage correcting method and unit and battery residual capacity estimating method and unitJP2002334726A Title not availableJPH0915311A Title not available* Cited by examinerReferenced byCiting PatentFiling datePublication dateApplicantTitleUS7843173 *Oct 17, 2007Nov 30, 2010Sony CorporationCharger and method of chargingUS8463564 *Sep 28, 2010Jun 11, 2013Mitsubishi Heavy Industries, Ltd.Abnormality prediction system for secondary batteriesUS20110077881 *Sep 28, 2010Mar 31, 2011Mitsubishi Heavy Industries, Ltd.Abnormality prediction system for secondary batteriesUS20120105013 *Oct 29, 2010May 3, 2012Gm Global Technology Operations, Inc.Apparatus of soc estimation during plug-in charge mode* Cited by examinerClassifications U.S. Classification320/132International ClassificationB60L11/18, H02J7/00, H01M10/44, G01R31/36, H01M10/48Cooperative ClassificationG01R31/3658, G01R31/362European ClassificationG01R31/36N2, G01R31/36V2Legal EventsDateCodeEventDescriptionSep 28, 2012FPAYFee paymentYear of fee payment: 4Feb 9, 2006ASAssignmentOwner name: PANASONIC EV ENERGY CO., LTD., JAPANFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:MURAKAMI, YUSAI;YAMABE, NORITO;REEL/FRAME:017566/0310Effective date: 20060127RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services©2012 Google