Analysis of lithium battery technology with BMS

Source: 2020 - 04 - 10 choicest hits: at present, aluminum nickel and cobalt acid lithium ( NCA) Although batteries in electric cars in the dominant, but may be replaced by other techniques. Because the battery management system ( BMS) Usually is the weak link electric car battery. Lithium cobalt oxide, although cheap, in high specific energy, does not provide 14 - 18 ampere moped as needed. Nimh batteries have been put into use, but the ratio can be less than half of the aluminum acid lithium cobalt nickel battery. Titanium lithium battery energy is lower than the lithium manganese batteries, lithium manganese battery only slightly higher than the titanium lithium batteries. Lithium iron phosphate batteries ( 联赛 The thermal runaway of temperature higher than 250 ℃, is a very safe and very long service life of the battery. However, it can lower than ( Less than half the NCA) Makes it less common in the small motor vehicles. Lithium nickel and cobalt aluminate ( NCA) Than to the highest, than for 250 - 290 wh/kg, but the high cost, low safety. The service life of them also each are not identical, charging an average between 500 and 1000, only half of the lithium iron batteries. Tesla used for thousands of pieces of nickel and cobalt 18650 lithium-ion batteries, and the more rigorous testing, to ensure that every piece of battery cell has the same quality, so as to improve the service life of batteries, thus avoided completely discharge and fully charged. And other brands of electric cars, tesla also provide the warranty period of eight years, keep your battery capacity in 80%, and limit the number of charging. However, few have been fully tested for electric bicycle batteries, even though it can increase production. Lithium nickel manganese cobalt acid salt ( NMC) The battery has been used for Renault and BMW their electric cars. According to samsung, it now than when can is 130 watts/kg ( About half of the NCA) , but by 2019 - Will reach 250-2020 300 w/kg. The NMC cost 12% to 19% higher than the NCA at present. As it becomes the mainstream of the electric car battery, its cost will be reduced, but the cost of the NCA almost no further to fall. The life and safety of NMC is far higher than that of NCA, so it will be a strong candidate for the future electric bicycle batteries. Oxis energy company, said the lithium battery is cheaper and longer life, the highest specific energy. In July 2013, the company's chief executive, said it has' readiness 'and GP batteries, but no sign of mass production. At present, 300 wh/kg lithium sulfur batteries and high-end diamond of nickel aluminate battery price is the same, but life is short. According to industry BBS, tesla would like to evaluate the new compounds, it is a stereotype, but they haven't got any. Lithium - Sulfur battery has its own advantages, but over a period of time to mature. Battery management system, a good battery management system has a temperature sensor can be used to detect a single battery voltage, and detect the weak battery before packing. This test to ensure 100% higher yield, higher the battery capacity and reduce warranty commitments. Good battery management system will record the mechanical impact, depth of discharge date and information, so it can avoid errors of the warranty claim. Good BMS can also detect the humidity of the battery pack, in order to avoid an accident. Better BMS group ( Funded by Erigineering Spiirit, he is CALCE electronics and systems research center at the university of Maryland high-tech electronics expert, is himself) In the 2014 European bike show BBMS specification based on the above information are presented. A large electric bicycle system company invited engineers elf ( BCT member) To design the BMS. Charge r&d in particular, they don't, don't allow a third party production in 4 a discharge flow, good battery resistance ( 0. 1 ohm) And poor cell ( 0. 4 ohm) Between the capacity of the difference is not obvious. Guarantee the low discharge current can continue on the good battery into battery. When the voltage reduction, inferior battery ( 0. 4 ohm) The power of 30% faster than high quality batteries. Good impedance and take the initiative to reduce current BMS can be monitored to delay without electricity. But the acceleration also fell sharply, it is time to change the battery.