| Lead-acid battery is one kind of chemic power supplies which has simple structure, convenient use and credible capability. Lead-acid battery is used broadly, which can be used on industry, agriculture, traffic and transportation, and national defense etc. With the development of productivity and technology, the lead-acid battery as the credible chemic power, at the same time, it is also the energy source of electric vehicle, so we should do some necessary administering and controlling to make sure the pile capacity keep good and long life. The battery capacity measurement becomes the key in the electric vehicle administering and controlling.The paper analyzed the relevant factors for battery capacity measurement, it turns out the discharge current, electrolyte temperature and electrolyte concentration can affect the measuring result. The paper also does some qualitative analysises on the charge-discharge voltage characteristic curve, the lead-acid battery capacity online measurement sensor based on fiber and intelligent information fuse technology is proposed.The main research content as follows:(1). Puts forward a testing method for lead-acid battery capacity based on fiber reflecting energy attenuation technology. Seen from the Lambert-Beer law, the optical absorption coefficient is related to the medium consistence, optical path and incidence energy, the paper research just based on the physics phenomena and theory, related the receiving optical energy to the electrolyte consistency, at the same time, the electrolyte consistency is related to the battery capacity, so we can get the battery capacity state by testing the lead-acid battery electrolyte consistency.(2) Based on the built measuring method, the author designed the lead-acid battery capacity on-line measuring sensor, researched on the sensor constitute theory, optical path and realization technology, carried out related experiment research. The result turned out the new method used on testing the battery capacity is feasible, the single probe structure sensor's relative error is less than 8.42%, in the testing process, and the electrolyte temperature change influenced the lead-acid battery capacity measuring result badly.(3) Aiming at the electrolyte temperature influencing the measuring result, put forward and designed the sensor with temperature compensation, improved the former single probe structure and introduced the double probe structure. This way make the sensor added measuring functions, which is battery capacity measure and liquor temperature measure. The improved sensor has two channels, one is used to measure electrolyte consistency and the other is used to measure reference liquid temperature change under the same measuring condition, which is established the base for eliminating temperature factor for measuring result.(4) In order to eliminate the temperature factor for measuring result, The author adopted some fitting means such as neural network (NN) and support vector machine (SVM) to build lead-acid battery capacity estimating module, the simulation result turned out that NN and SVM all have learning performance of fitting function with any precision. Under the conditions of few sample number, the SVM has better fitting precision than the NN, at the same time the SVM use fewer training time than BP NN. The improved double-probe structure sensor measuring system adopts estimating module to do simulation measure and the testing relative error can reduced to less than 3.25%. So the improved structure sensor is better than the former single probe structure sensor.Aiming at research work of lead-acid battery residual capacity, the paper just involves the BP NN fitting and SVM fitting modeling of lead-acid battery charge-discharge course, and the study parameter just involves measuring signal voltage and reference liquid output signal voltage, the more parameters need deeply research.
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