Sigma Tek lithium battery SOC and SOH functions

　　SOC refers to the state of charge, also known as remaining power, which represents the ratio of the remaining capacity of a battery after a period of use or long-term storage to its fully charged capacity, often expressed as a percentage. The value range is 0 to 1. When SOC=0, it indicates that the battery is fully discharged, and when SOC=1, it indicates that the battery is fully charged. The SOC of lithium ion batteries cannot be measured directly, but can only be estimated through parameters such as battery terminal voltage, charge and discharge current, and internal resistance. These parameters are also affected by various uncertain factors such as battery aging, environmental temperature changes, and vehicle driving status. Therefore, accurate SOC estimation has become an urgent issue in the development of electric vehicles.

　　SOH refers to the capacity, health, and performance status of a battery. In simple terms, it refers to the ratio of the performance parameters to the nominal parameters of the battery after a period of use. For new batteries, it is 100%, and for fully scrapped batteries, it is 0%. "The ratio of the capacity of a battery discharged from a full charge state at a certain rate to the cut-off voltage to its corresponding nominal capacity, which is simply understood as the limit capacity of the battery.". There is a certain relationship between the internal resistance of the battery and SOH. The lower the SOH, the greater the internal resistance of the lithium ion battery. By detecting data such as voltage, current, and temperature, the internal resistance value of the battery is indirectly calculated, and then the SOH is calculated based on the relationship between SOH and the internal resistance of the battery. However, the internal resistance of the battery does not change significantly when the SOH change range is small, while the resistance value changes greatly when the battery is severely aged. Therefore, when the SOH change is small, the measurement error will be large.

pre：SigmasTek Sigmas Tek Battery AGM Sigmas Batteries

next：Why does the battery quickly run out of power after being fully charged.