SOH (state of health) estimation method for power battery

The invention discloses an SOH (state of health) estimation method for a power battery and belongs to the technical field of power batteries. The method comprises the following steps of: charging a battery pack in a discharge cut-off state to a fully charged state in a set temperature range; calculating the maximum total available capacity of the battery pack according to available capacity of the battery pack in the discharge cut-off state and total charging capacity of the battery pack in the fully charged state; and estimating the SOH of the battery pack according to the total capacity of the battery pack and set initial nominal capacity. According to the method disclosed by the invention, the SOH of the battery pack is estimated by utilizing the inherent characteristic of the battery pack, namely the maximum total available capacity of the battery pack, an internal chemical model and state parameters of the battery pack do not need to be known, and the difficulties that mathematical modeling, state parameter identification and off-line test cannot be performed inside the battery, lots of experimental data are needed and the like are overcome, so that the SOH in the full life circle of the battery pack can be estimated, and an estimated object is not limited to the battery pack of a certain specific type of battery cells.