Outline

Incremental Capacity Analysis definition

The impedance is the opposition to alternating current presented by the combined effect of resistance and reactance in a circuit. Commonly, in a battery it is defined by the voltage drop when a current is applied.

$$ ICA= { \Delta Q \over \Delta V }$$ with

  • ICA : the Incremental Capacity Analysis (Ah/V)
  • ΔQ : the capacity variation (Ah)
  • ΔV : the voltage variation (V)

Analysis preparation

DATTES is called as follows : [result]=dattes(XML_file,'action','configuration_file'). Before any analysis, it is then necessary to create the XML and configuration files.

The section Import cycler files explains how to create the XML file.

The section Create a configuration file explains how to create a configuration file.

Anomaly detection

Incremental Capacity Analysis tests may be affected by noisy voltage measurements.

To check if an Incremental Capacity Analysis test have run normally the action ‘GI’ should be used : [result] = dattes(XMLfile,'GI');

image

Incremental Capacity Analysis analysis

To analyze the incremental capacity analysis, the action ‘I’ should be used :

[result] = dattes(XMLfile,'Ivs');

The output are :

Output structure Field Array Unit Description
result ica dqdu Ah/V Voltage derivative of capacity
result ica dudq V/Ah Capacity derivative of voltage
result ica q Ah Capacity vector for dudq
result ica u V Voltage vector for dqdu
result ica crate - Current rate for the ica test
result ica time s Time of measurement of the ica test

Code for vizualization

To visualize the resistance, the action ‘GI’ should be used :

[result] = dattes(XMLfile,'GI');

The graph should look like

image

Methodology and Hypothesis

Method

All the array from result.ica are determined thanks to function extract_phase :

for ind = 1:length(phasesICA)
    [tp,Up,DoDAhp] = extract_phase(phasesICA(ind),t,U,DoDAh);
    
    [ica(ind).dqdu, ica(ind).dudq, ica(ind).q, ica(ind).u] = calcul_ica(tp,DoDAhp,Up,N,wn,f_type);
    ica(ind).crate = phasesICA(ind).Iavg/config.Capa;
    ica(ind).time = phasesICA(ind).t_fin;
end

Key quantities for the calculation

The six key parameters for the analysis of ica are :

  • config.pICAC,
  • config.pICAD,
  • config.n_filter,
  • config.wn_filter,
  • config.filter_type,
  • config.Capa.

Assumptions and possible simplifications

No major assumptions or simplifications have been made

Contribute to ica analysis

A list of open issues related to ica calculation and visualization may be available here.