How to improve the efficiency and life of electric vehicle batteries?

How to improve the efficiency and lifetime of electric vehicle batteries has always been a hot topic. Electric vehicles and hybrid vehicles provide an excellent way to save energy and reduce carbon dioxide emissions. But the important disadvantage of electric vehicles and hybrid vehicles is their battery capacity and the travel restrictions that result from them. Since the maximum battery capacity standard of a car usually depends on volume and weight, optimizing the capacity of existing batteries becomes increasingly important. In order to meet the hundreds of volts required by modern high-performance electric vehicle batteries, several independent batteries are usually connected in series. Each battery in the battery pack has a different capacity, self-discharge rate, temperature characteristics, battery impedance, etc. These differences will increase as the battery ages. When the batteries are charged, this difference causes some batteries to not be fully charged, while others are already fully charged. Unless the rated method is used, the charging process must be interrupted, because if the battery is overcharged, damage or even complete damage will occur. A similar phenomenon occurs during the discharge process. In contrast, one battery has been completely discharged, and the other battery has enough energy to continue to power the car (theoretically). However, the trolley may not be able to continue walking at this time, because this will over-discharge the weak battery unit, and the action will damage the battery unit. To prevent these two conditions, a positive balance between each cell is necessary. Forced balance method converts available energy into heat loss. A widely used method is forced balance technology, which uses a resistor to re-discharge a fully charged battery so that other batteries can continue to be charged. The disadvantages of this method are obvious: *In order to maintain balance, the battery can only be discharged *The discharge current of the bypass resistor causes power loss *Precious energy is converted into heat energy, which can not supply power to the car *Short the distance between the cars to force a balance Only the energy stored in the battery is converted into heat loss, while active balancing transfers the charge from one battery to another. There are several methods of charge transfer, such as using switched capacitors or inductors. When the capacitive method is used, the capacitor is connected in parallel with the battery at a higher voltage. Once the battery is fully charged, it is connected in parallel with the lower voltage battery and can be continuously charged. Repeat this process until all batteries have reached the same voltage gap. The capacitor method is cost-effective, but its disadvantage is that the uniform balance current is limited to less than 50mA. This combination does not exist in the induction method, in this case it is easy to reach a balance current of 1A or more. Fast and almost lossless charge transfer is achieved through active balancing. Active balancing is accomplished by a parallel inductor and a charged battery. This action causes the current in the coil to continue to be added. Once the coil is discharged from the battery through the transistor, the energy stored in the inductor can be charged to the adjacent battery through the diode. Therefore, the charge can be moved back and forth between two independent batteries with extremely high power and almost no loss. This method has some decisive benefits: *The equalization current can reach 1A or more*The balance is basically lossless*The balance bar is very fast*The power supply and battery capacity are added*The driving interval of the car is added to the previously mentioned Compared with other methods, the use of inductors to achieve active balancing is not a low-cost method, because the cost of temporarily used inductive components is relatively high. But this is not entirely a problem. The price of modern high-performance batteries is now close to $10,000. Using the inductance balance method, even if only 10% of the rated capacity is obtained, it is equivalent to a value of $1,000, which can be used to purchase a large number of inductive devices. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous post: What are the requirements for the manufacture of lithium battery electrolyte?