Method for categorizing a battery with respect to its further handling suitability, wherein according to the method - during operation of the battery, a plurality of safety-relevant and lifetime-relevant operating variables are registered for at least one battery cell of the battery, - a categorization variable is determined by means of a two-step evaluation of at least one of the operating variables and/or of a computed variable derived therefrom, characterized in that + in a first step, for at least one safety-relevant operating variable, a safety variable is derived and compared with an assigned threshold value, + if the threshold value or one of the possibly multiple threshold values is undershot, in a second step a failure prognosis is prepared by means of a plurality of the lifetime-relevant operating variables, and + the categorization variable is determined on the basis of the failure prognosis, wherein in the first step, for at least one battery cell of the battery, a history variable, which is characteristic of a preceding operating load, is ascertained on the basis of the at least one safety-relevant operating variable which has been ascertained for this battery cell and is the temperature, the voltage, a pressure, and/or the gas concentration of a decomposition gas, wherein in the second step, for at least one battery cell of the battery, the failure prognosis is ascertained by means of the lifetime-relevant operating variables on the basis of a statistical model, in which the operating variables of the operating duration of the battery cell, number of cycles of the battery cell, capacity of the battery cell, quick-charged total amount of power, and/or mileage of a motor vehicle comprising the battery are incorporated, wherein the failure prognosis of the or the respective battery cell is assigned on the basis of its numerical value to a value range of the categorization variable, and wherein at least the value ranges "like new", "vehicle use", "second utilization", and "recycling" are assigned to the categorization variable and appropriate recommendations or suggestions for further handling are indicated to the user of the battery. - during operation of the battery, a plurality of safety-relevant and lifetime-relevant operating variables are registered for at least one battery cell of the battery, - a categorization variable is determined by means of a two-step evaluation of at least one of the operating variables and/or of a computed variable derived therefrom, characterized in that + in a first step, for at least one safety-relevant operating variable, a safety variable is derived and compared with an assigned threshold value, + if the threshold value or one of the possibly multiple threshold values is undershot, in a second step a failure prognosis is prepared by means of a plurality of the lifetime-relevant operating variables, and + the categorization variable is determined on the basis of the failure prognosis, + in a first step, for at least one safety-relevant operating variable, a safety variable is derived and compared with an assigned threshold value, + if the threshold value or one of the possibly multiple threshold values is undershot, in a second step a failure prognosis is prepared by means of a plurality of the lifetime-relevant operating variables, and + the categorization variable is determined on the basis of the failure prognosis, wherein in the first step, for at least one battery cell of the battery, a history variable, which is characteristic of a preceding operating load, is ascertained on the basis of the at least one safety-relevant operating variable which has been ascertained for this battery cell and is the temperature, the voltage, a pressure, and/or the gas concentration of a decomposition gas, wherein in the second step, for at least one battery cell of the battery, the failure prognosis is ascertained by means of the lifetime-relevant operating variables on the basis of a statistical model, in which the operating variables of the operating duration of the battery cell, number of cycles of the battery cell, capacity of the battery cell, quick-charged total amount of power, and/or mileage of a motor vehicle comprising the battery are incorporated, wherein the failure prognosis of the or the respective battery cell is assigned on the basis of its numerical value to a value range of the categorization variable, and wherein at least the value ranges "like new", "vehicle use", "second utilization", and "recycling" are assigned to the categorization variable and appropriate recommendations or suggestions for further handling are indicated to the user of the battery.