Technical status and development prospect of battery for electric vehicle With the rapid development of the automobile industry, it has promoted the development of the industry and the development of economy and transportation. However, the defects of energy consumption, environmental pollution inherent in the traditional internal combustion engine automobile has been affected and perplexing peoples life and social development, with the development of society and technology, protect the environment and conserve resources with the rising, a new generation of electric vehicles and electric vehicles as no pollution and energy new traffic tools diversified configuration, in recent years has aroused widespread concern and has been greatly developed. One of the jobs of Beijing to make the 2008 Olympic Games a green Olympic Games is to replace the current internal combustion engine with environmentally friendly electric vehicles. Electric vehicle with electric drive, driving without emission (or low emission), low noise, energy conversion efficiency is much higher than the internal combustion engine, and the electric vehicle has the advantages of simple structure, low operation cost, safety is better than that of internal combustion engine. But electric vehicles still exist in higher prices, continued driving mileage is short, the dynamic performance is poor, and these problems are closely related and power supply technology, the practical difficulties of electric vehicles still in power technology, especially the battery (chemical power technology). At present, the key factor restricting the development of electric vehicles is the power battery is not ideal, and the development of electric vehicle competition, the most important thing is to develop the competitive power battery. Electric vehicle power battery and starter batteries different, it is a long time continuous medium current discharge, or to discharge (starting, acceleration), and to use the main deep circulation. The basic requirements for battery electric vehicles can be summarized as follows: 1, high energy density and high power density; 2; 3, longer cycle life; 4, good charge and discharge performance of battery; 5, good consistency; 6, the price is low; 7, convenient use and maintenance etc. The current research and development of electric vehicle batteries including lead-acid batteries, nickel metal batteries, lithium ion battery, high temperature sodium batteries, metal air battery, super capacitor, super capacitor and the flywheel battery has better development prospect of fuel cell and solar cell.1, lead-acid batteryLead acid battery has a history of more than 100 years, it is widely used as the starting power source of internal combustion engine. The positive and negative electrodes of lead acid battery are two lead oxide and lead, and the electrolyte is sulfuric acid. Lead acid batteries can also be divided into two categories, namely, water injection lead-acid batteries and valve regulated lead-acid batteries. The former is cheap, but the need for frequent maintenance, added electrolyte; the excess gas safety control valve, sealing the battery in charging or abnormal work in automatic regulation of free maintenance, more in line with the requirements of electric vehicles. Generally speaking, the lead-acid battery has the advantages of good reliability, easy access to raw materials, low price, etc., and the specific power can basically meet the power requirements of electric vehicles. But it has two major shortcomings: first, the lower energy, the quality and volume is too large, and a charging mileage shorter; the other is a short service life, the use of high cost. Because of the lead-acid battery technology is relatively mature, the lead-acid battery further improved after will remain the main source of electric vehicle in the near future, electric vehicles are being developed by the advanced lead-acid battery mainly has the following several kinds: horizontal bipolar lead-acid batteries, sealed lead-acid battery, coil type electric pole lead-acid battery etc.2, nickel metal batteriesA nickel cadmium battery and Ni MH battery two main nickel metal batteries currently used in electric cars. Compared to cadmium nickel battery and lead-acid battery, can achieve energy than 55Wh/kg, than the power of 200W/kg, the cycle life of 2000 times, and can fast charge, although the price of lead-acid battery 4 to 5 times, but because of its life in the field of energy use and advantages, so the long-term practical use cost is not high. However, due to its heavy metal cadmium, in the use of no attention to recycling, it will form environmental pollution, many developed countries have restricted the development and use of nickel cadmium batteries. The Ni MH battery is a green nickel battery, the positive and negative poles were nickel hydroxide and hydrogen storage alloy material, there is no heavy metal pollution problems,