Method and apparatus for electronically evaluating the internal temperature of an electrochemical cell or battery

A method for electronically evaluating the internal temperature of an electrochemical cell or battery comprising the steps of:

• applying multiple frequency electrical excitation to said cell or battery;
• sensing an electrical response to said multiple frequency electrical excitation;
• combining values of said multiple frequency electrical excitation and said electrical response mathematically to obtain a computed result;
• and
• evaluating said internal temperature from said computed result.

A method for implementing a temperature correction of a measured property of an electrochemical cell or battery comprising the steps of:

• applying multiple frequency electrical excitation to said cell or battery;
• sensing an electrical response to said multiple frequency electrical excitation;
• combining values of said multiple frequency electrical excitation and said electrical response mathematically to compute a temperature correction factor;
• and
• adjusting the value of said measured property in accordance with said computed temperature correction factor.

A method for detecting thermal runaway of an electrochemical cell or battery undergoing charging comprising the steps of:

• applying multiple frequency electrical excitation to said cell or battery;
• sensing an electrical response to said multiple frequency electrical excitation;
• determining the internal temperature of said cell or battery from values of said multiple frequency electrical excitation and said electrical response;
• and
• responding to an abnormal increase in said internal temperature between successive internal temperature determinations.