| With the development of the battery usage, the accurate estimate of battery capacity is getting more and more important, therefore it becomes the research article by many researchers in embeded system field. But the battery capacity is not a parameter that can be measured directly. And many facts maybe affect it, such as temperature, discharge rate and the aging.This paper begins discussion with the current measurement technology. Firstly, it talks about the disadvantage of the current measurement solution then based on the powerful background and the database of some America company, builds a battery capacity referring model focusing on the chemistry character of the battery. The solution is mainly based on the Ampere Hours counting and also takes many factors into account, which can affect the estimate of battery capacity. It can adjust the weighting of these factors according to the battery's different status. When the battery system is open circuit, because there is a very accurate relation between the open circuit voltage and the State of Charge, so if the battery is not imposed to loads and in release status, the voltage solution can get an accurate estimate of battery capacity. When the system is in working status and imposed to loads, the current solution is implemented. And when the battery's voltage is dropped too much, the solution will consider the discharge curve and achieve to learn its capacity after a complete discharge and also protect the battery from the over discharge. So after the voltage and current solution is combined and the temperature compensation is involved, a new solution for battery capacity estimating comes out. This solution has been implemented to the real engineering projects, and it is feasible after real test.According to the above estimation solution, the paper has complete a lot of experiments and engineering test, and the precision of the estimating is verified and controlled within 1%. So the accurate estimating is carried out. |
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