Method for determining an overall loss of capacitance of a secondary cell

摘要

A method for determining an overall loss of capacitance of a secondary cell, for example of an accumulator, which is brought about by ageing processes is provided. The overall loss of capacitance is determined additively from partial losses of capacitance which are determined by means of various parameters from various functions. A partial loss of capacitance is determined under constant peripheral conditions. If the peripheral conditions change, the partial losses of capacitance follow one another directly, i.e. with respect to the same loss of capacitance. The interval of the respective charge throughput rate is shifted here. The overall loss of capacitance of a secondary cell can be extended to the overall loss of capacitance of a package composed of a plurality of secondary cells.

主权项

1. A method for determining an overall loss of capacitance of a secondary cell for a first interval from a first initial value of a first charge throughput up to a first final value of a second charge throughput, and for a second interval, following the first interval, from a second initial value of a third charge throughput up to a second final value of a fourth charge throughput, comprising:
determining a first partial loss of capacitance for the first interval, defined by a difference between a loss of capacitance at the first final value of the second charge throughput and the loss of capacitance at the first initial value of the first charge throughput, the first final value being part of a first function; determining a second partial loss of capacitance for the second interval, defined by a difference between the loss of capacitance at the second final value of the fourth charge throughput and the loss of capacitance at the second initial value of the third charge throughput, the second final value being part of a second function; and determining the overall loss of capacitance by means of adding the first partial loss of capacitance and the second partial loss of capacitance; wherein a result value of the second function for the second initial value corresponds to a result value of the first function for the first final value and wherein the first partial loss and the second partial loss of capacitance are determined by a means of measurements on at least one secondary cell.