Vehicle, and equalization method and device for power battery pack
AssigneeBYD Company Limited
InventorsTianyu Feng, Linwang Deng, Chun Lv, Siqi Lin, Zihua Yang
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Abstract
Disclosed are an automobile, and a power battery pack equalization method and device, the method comprises the following steps: acquiring a high voltage inflection point of the charging curve of a battery cell of the power battery pack and acquiring the capacity of the battery cell according to the high voltage inflection point of the battery cell, and equalizing the battery cell according to the capacity of the battery cell. Hence, equalization management of the power battery pack can be realized, thereby improving the use ratio of the power battery pack and prolonging the service life of the power battery pack.
Claims18
An equalization method for a power battery pack comprising a plurality of cells, the method comprising:
- obtaining a high voltage turning point of a charging curve of each of the cells of the power battery pack;
- wherein
- the charging curve comprises a middle voltage platform charging stage followed by a high voltage platform charging stage, the charging curve enters the middle voltage platform charging stage after passing a low voltage turning point, and the charging curve enters the high voltage platform charging stage after passing the high voltage turning point, and
- turning points comprise positive peaks of a dV/dQ first-order derivation curve of the charging curve, and when a peak value of one of the turning points is higher than a threshold, the one of the turning points is determined as the high voltage turning point;
- obtaining a capacity of each of the cells according to the high voltage turning point;
- and
- equalizing the cells according to the capacities of the cells.
An equalization device for a power battery pack comprising a plurality of cells, the device comprising:
- a first obtaining module configured to obtain a high voltage turning point of a charging curve of each of the cells of the power battery;
- wherein
- the charging curve comprises a middle voltage platform charging stage followed by a high voltage platform charging stage, the charging curve enters the middle voltage platform charging stage after passing a low voltage turning point, and the charging curve enters the high voltage platform charging stage after passing the high voltage turning point, and
- turning points comprise positive peaks of a dV/dQ first-order derivation curve of the charging curve, and when a peak value of one of the turning points is higher than a threshold, the one of the turning points is determined as the high voltage turning point;
- a second obtaining module configured to obtain a capacity of each of the cells according to the high voltage turning point;
- and
- a control module configured to equalize the cells according to the capacities of the cells.
An electric vehicle, comprising:
- a power battery pack comprising a plurality of cells, wherein the power battery pack is used as a power source for the electric vehicle;
- and
- an equalization device for the power battery pack comprising:
- a first obtaining module configured to obtain a high voltage turning point of a charging curve of each of the cells of the power battery;
- wherein
- the charging curve comprises a middle voltage platform charging stage followed by a high voltage platform charging stage, the charging curve enters the middle voltage platform charging stage after passing a low voltage turning point, and the charging curve enters the high voltage platform charging stage after passing the high voltage turning point, and
- turning points comprise positive peaks of a dV/dQ first-order derivation curve of the charging curve, and when a peak value of one of the turning points is higher than a threshold, the one of the turning points is determined as the high voltage turning point;
- a second obtaining module configured to obtain a capacity of each of the cells according to the high voltage turning point;
- and
- a control module configured to equalize the cells according to the capacities of the cells.
Dependencies are inferred from the claim text.