A charging device, configured to charge a battery, wherein the charging process of the battery comprises at least one constant current stage, and the at least one constant current stage comprises a first constant current stage, and comprising: a processing circuit, configured to determine an open circuit voltage of the battery according to a pre-established model and a first parameter of the battery in the charging process; and a charging management circuit, configured to, in the first constant current stage, charge the battery with a first current until the open circuit voltage of the battery reaches a first cut-off voltage and/or a charging voltage of the battery reaches a preset target value, the first cut-off voltage being less than or equal to a standard limited charging voltage of the battery, wherein the first parameter comprises at least one of the following parameters: a charging voltage, a charging current, a quantity of electricity, and a temperature, and the pre-established model comprises a corresponding relationship between the open circuit voltage of the battery and at least one of the first parameters, and wherein the pre-established model, established between open circuit voltages, charging currents, temperatures and quantities of electricity of batteries, is realized by processes of: selecting batteries of a same batch with a same model, performance, parameters and manufacturing process, charging the batteries to different quantities of electricity at different temperatures and with different charging currents, and measuring the open circuit voltages of the batteries after standing for a period of time. a processing circuit, configured to determine an open circuit voltage of the battery according to a pre-established model and a first parameter of the battery in the charging process; and a charging management circuit, configured to, in the first constant current stage, charge the battery with a first current until the open circuit voltage of the battery reaches a first cut-off voltage and/or a charging voltage of the battery reaches a preset target value, the first cut-off voltage being less than or equal to a standard limited charging voltage of the battery, wherein the first parameter comprises at least one of the following parameters: a charging voltage, a charging current, a quantity of electricity, and a temperature, and the pre-established model comprises a corresponding relationship between the open circuit voltage of the battery and at least one of the first parameters, and wherein the pre-established model, established between open circuit voltages, charging currents, temperatures and quantities of electricity of batteries, is realized by processes of: selecting batteries of a same batch with a same model, performance, parameters and manufacturing process, charging the batteries to different quantities of electricity at different temperatures and with different charging currents, and measuring the open circuit voltages of the batteries after standing for a period of time. selecting batteries of a same batch with a same model, performance, parameters and manufacturing process, charging the batteries to different quantities of electricity at different temperatures and with different charging currents, and measuring the open circuit voltages of the batteries after standing for a period of time.