Power source balancing method of electric car

Abstract

The invention relates to a power source balancing method of an electric car. The power source balancing method comprises the following steps of: (1) establishing an actual SOC (State of Charge) value of each single battery; and (2) carrying out charging / discharging balance on the single battery according to a difference value between the actual SOC value of each single battery and an average SOC value of a battery pack, and a difference value between voltage of the each single battery and average voltage of the battery pack. The invention provides a storage battery active balancing scheme; an SOC parameter of the single battery is used as a balance object to improve an amper-hour integral method; the battery capacity can be revised in real time and the accurate SOC value is obtained; and the capacity difference between the single batteries in a storage battery pack can be reduced, the balance efficiency is high, the loss is small, and the service life of the battery pack is greatly prolonged.

Description

technical field [0001] The invention relates to the field of electric vehicles, in particular to a method for equalizing the power source of the electric vehicle. Background technique [0002] For a long time, rechargeable batteries as the power source of electric vehicles have been the most important factor limiting the development of electric vehicles. In this regard, domestic and foreign institutions and related companies have invested a lot of manpower and material resources in research. Whether the battery can meet the requirements of electric vehicles in various sports situations (such as starting, climbing, accelerating, fast charging) needs to be based on the analysis and detection of the charging and discharging characteristics of the battery. [0003] The storage battery is the energy source of the electric vehicle. In order to ensure the good performance of the battery pack and prolong the service life of the battery, it is necessary to carry out necessary man...

AI Technical Summary

Problems solved by technology

[0006] (1) Resistance equalization method. A large resistor is connected in parallel to each single battery in the series battery pack. The battery with higher voltage will consume more energy on the parallel resistor. Although this method is simple and easy to implement, it has disadvantages It consumes a lot of energy, and can only discharge the battery cells but not charge them, and other battery cells must use the lowest cell as the standard to achieve balance, and the efficiency is low;

[0007] (2) The voltage equalization method takes the voltage parameters of each battery as the equalization object, and makes the voltage of each single battery consistent through equalization charging. This method solves the problem of unbalanced battery voltage, but the battery with low capacity in the battery pack is When charging or after charging, its terminal voltage may be higher than that of other batteries. If this equalization method is adopted, the result of equalization is that the battery with low capacity charges the battery with high capacity, which increases the capacity difference between individual batteries;

[0008] (3) The battery SOC balance method takes the state of charge SOC parameters of each battery as the balance object, that is, when the SOC of each single battery in the battery is inconsistent, it is balanced by the method of balanced charging. This method of balanced charging It is often the battery with a larger capacity in the battery pack that is used to improve the SOC, so this method can only solve the problem of performance degradation of the cells with a larger capacity in the battery pack due to long-term insufficient charging, and cannot reduce and eliminate the problems of each unit in the battery pack. body capacity gap

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