| US 7,557,584 B2 | ||
| Method and device for estimating charge/discharge electricity amount of secondary cell | ||
| Yusai Murakami, Hamamatsu (Japan); and Norito Yamabe, Toyohashi (Japan) | ||
| Assigned to Panasonic EV Energy Co., Ltd., Kosai-Shi (Japan) | ||
| Appl. No. 10/565,956 PCT Filed Jul. 26, 2004, PCT No. PCT/JP2004/010983 § 371(c)(1), (2), (4) Date Jan. 26, 2006, PCT Pub. No. WO2005/010540, PCT Pub. Date Feb. 03, 2005. |
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| Claims priority of application No. 2003-282037 (JP), filed on Jul. 29, 2003; and application No. 2004-202931 (JP), filed on Jul. 09, 2004. | ||
| Prior Publication US 2006/0232277 A1, Oct. 19, 2006 | ||
| Int. Cl. G01N 27/416 (2006.01) | ||
| U.S. Cl. 324—429 [320/149; 320/132] | 8 Claims |
| 1. A method for estimating a charge/discharge electricity amount of a secondary battery comprising:
a step of measuring a pair of data consisting of a current flowing through the secondary battery and a terminal voltage of
the secondary battery corresponding to the current, thus obtaining a plurality of pairs of data,
a step of, when specific selection conditions are satisfied, the specific selection conditions including (i) the current in
charging and discharging the secondary battery is within a first predetermined range, (ii) a number of the plurality of pairs
of data is greater than or equal to a predetermined number, and (iii) a charge/discharge electricity amount during collection
of the plurality of pairs of data is within a second predetermined range, calculating a no-load voltage as a voltage intercept
at a current of zero in a straight-line approximation obtained by statistical processing with respect to the plurality of
pairs of data,
a step of, when the specific selection conditions are not satisfied and one of specific current conditions and voltage conditions
continue to be met for a certain amount of time, calculating an open circuit voltage from the terminal voltage of the secondary
battery, the component resistance of the secondary battery and an average current,
a step of calculating a change (ΔVb) in the no-load voltage or the open circuit voltage over a predetermined period of time, and
a step of calculating an estimated charge/discharge electricity amount (ΔQe) of the secondary battery based on the change in the no-load voltage or the open circuit voltage.
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