Analysis of SOC estimation method for remaining power of lithium battery

Open circuit voltage method: firstly measure the open circuit voltage values u200bu200bat different temperatures and different SOCs to form a table. After the battery system is installed in the vehicle, whenever the power supply is stopped, the table data can be called to judge the battery state of charge based on the measured open circuit voltage. Ampere-hour integration method: measure the current of the main circuit of the lithium battery pack in real time, and integrate it over time, charging is negative and discharging is positive. In the discharging process, the initial power is subtracted from the integration result to obtain the current power; the initial power is used in the charging process to add the integration result to the current power. Internal resistance method: The tendency of internal resistance to follow the SOC change is very gentle, and a small internal resistance change or measurement error can cause a large error in the SOC value. The measurement contact resistance is too large, the battery current is large, and there is a large polarization internal resistance interference; the inconsistent temperature rise of the lithium battery makes the temperature of the temperature monitoring point and the battery body temperature inconsistent, resulting in deviations in temperature compensation, and so on. Kalman filter algorithm: The core idea is to calculate the current optimal value based on the current measurement value of the instrument, the forecast at the previous moment, and the error. The highlight is that the error is included in the calculation, and the error exists independently and is not affected by the measurement data. Neural network algorithm: A new algorithm that simulates the human brain and neurons to solve the nonlinear system. There is no need to deeply study the internal structure of the lithium battery, just extract the input and output samples that meet the working characteristics from the lithium battery in advance and input them In the establishment of the system, the SOC value in operation can be obtained. Disclaimer: Some pictures and content of the articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous article: Brief introduction of lithium battery energy storage technology and market outlook