Abstract: The present invention is an integrated method and apparatus for determining the quality of electrochemical energy storage devices, especially batteries. The invention is based on an integrated usage of electromagnetic and ultrasonic energy to probe of the interior volume of the battery. The first probe is carried out when the battery is at an initial charged state. After the first probe stage, a discharge of the battery being diagnosed is carried out until the test battery is at a small fixed test charge value. Signals from the eddy current probes allow determination of the continuity of the discharge current during the discharge process. After the discharge of the battery, the above described test sequence is repeated. The resultant eddy current signal generated at the initial state of the battery and the gradients of the eddy current signal and of the ultrasonic signal versus the battery capacity is determined.