Electric vehicle power lithium ion battery BMS technology -Lithium - Ion Battery Equipment
What is the core technology of BMS?
Recently, I saw a propaganda sign of a domestic company. Because of the underlying software such as the software architecture of AutoSAR, it claimed to fully master BMS software and hardware technology, reached the world's advanced level, and adopted multiple equilibrium control capabilities. Very attracting attention. Are these things the core technology of BMS?
The BMS system usually includes the detection module and the computing control module.
Detection refers to the voltage, current and temperature of the battery, and the voltage of the battery pack, and then pass these signals to the computing module for processing instructions. So the computing control module is the brain of BMS. Control modules generally include hardware, basic software, runtime environment (RTE) and application software. The core part-application software. The environment developed with Simulink is generally divided into two parts: estimated algorithms and fault diagnosis and protection of battery status. Status estimation includes SOC (StateOfcharge), SOP (Stateofpower), SOH (Stateofhealth), and equilibrium and thermal management.(Lithium - Ion Battery Equipment)
Battery state estimates are usually estimated to SOC, SOP and SOH. SOC (Loading Status) is simply how much power is left in the battery; SOC is the most important parameter in BMS because everything else is based on SOC, so its accuracy and robustness (also known as correction error correction (also called correction error correction Ability) Extremely important. If there is no precise SOC, the additional protection function cannot work normally, because the battery is often protected, and the life of the battery cannot be extended. In addition, SOC's estimation accuracy is also very important. The higher the accuracy, the battery of the same capacity can have higher endurance mileage. Therefore, high -precision SOC estimates can effectively reduce the cost of battery. For example, Chrysler's Fiat 500EBEV can always discharge SOC = 5%. Become the longest range of electric vehicles at the time.
SOP's precise estimation can maximize the efficiency of battery utilization. For example, you can absorb the energy of feedback as much as possible without harming the battery. You can supply greater acceleration when you accelerate the power without harming the battery. At the same time, it is also possible to ensure that the vehicle does not lose power due to under pressure or overcurrent protection during driving even when SOC is very low. In this way, the so -called first -level protection and secondary protection are all over -the -time SOP. It doesn't mean that protection is not important. Protection is always required. But it cannot be the core technology of BMS. For low temperature, old batteries, and low SOCs, accurate SOP estimates are particularly important. For example, about a set of well-balanced battery packs, when a relatively high SOC, each SOC may be small, such as 1-2%. However, when the SOC is very low, a certain battery voltage will drop rapidly. The voltage of this cell is even more than 1V than other batteries. To ensure that each battery voltage is not lower than the minimum voltage given by the battery supplier, the SOP must accurately estimate the maximum output power of the battery with a rapid decrease of the battery in the next moment to protect the battery. The core of the SOP is to estimate every equivalent impedance of the battery online in real time.
SOH refers to the health of the battery. It includes two parts: the changes in the capacity and power of Ashishi. It is generally believed that when the capacity attenuation at the time of peace or the output power attenuation 25%, the life of the battery will arrive. However, this does not mean that the car cannot be driven. For pure electric vehicle EV, the estimation of peaceful capacity is more important. Power limit is only important because it has a direct relationship with the mileage. Regarding HEV or PHEV, changes in power are even more important. This is because the time capacity of the battery is relatively small, and the power that can be supplied is limited, especially at low temperature. The requirements for SOH are both high accuracy and robustness. And there is no sense of SOH without robustness. The accuracy is less than 20%, it is meaningless. SOH's estimation is also based on SOC estimates. So the SOC algorithm is the core of the algorithm. The battery status estimation algorithm is the core of BMS. The others serve this algorithm. So when someone claims to break through or master the core technology of BMS, he should ask him what he has done BMS?