This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Analysis of Lithium-Ion Battery through Direct Current Internal Resistance Characteristic
Abstract:
The accuracy of real-time status assessment during the charging and discharging
process of the lithium-ion battery directly affects driving safety, and
high-precision evaluation of real-time status has always been an important
research area. The direct current internal resistance (DCIR) characteristic of
the battery is an important characteristic of the battery. The discharge process
at a temperature of 25°C is studied in this article. The results show that DCIR
under dual-current test and single-current test have similar trends with
different states of charge (SOCs) during the discharge process, and the main
difference between them is reflected in the polarization internal resistance
(IR). The relationship and difference between the DCIR value under the
dual-current test and the fitted value based on the fully discharged state are
studied, and the error value between the calculated value and the fitted value
of the corresponding SOC is within 5 mΩ. The article also proposes a real-time
state evaluation model based on DCIR in which the evaluation error of the
battery in the early discharge state is within 50 mV by adjusting the parameter
K. There are certain connections and differences between
DCIR obtained by dual-current test and single-current test in different SOCs. In
this article, the battery status during the discharge process is evaluated based
on DCIR obtained by dual-current test and single-current test, but the
optimization algorithm for designing the battery status in combination with
DCIR, different temperature gradients, and charge and discharge rates needs to
be further studied.