1. An integrated method for determining the quality of flat or prismatic batteries comprising the steps of: probing of the inner volume of a battery found in its initial charged state with ultrasonic pulses in a high-frequency shadow fill mode by using ultrasonic probes containing polyurethane protectors for ultrasonic energy injection; probing of the inner volume of a battery found in its initial charged state with an eddy magnetic field by using eddy current probes spatially integrated with ultrasonic probes and arranged on both sides of a flat battery; discharging the battery being diagnosed to a low fixed test charge value; using the signals of the eddy current probes for determining continuity of the discharge current during the test discharge process; repeated battery probing with ultrasonic pulses after the test discharge; determining the signals of the eddy current probes after the testing discharge; forming of a resultant eddy current signal; determining the deviation of the resultant eddy current signal generated at the initial state of the battery being diagnosed from the average state of the same signal preliminary obtained on the training sample of batteries; determining the ultrasonic signal gradient versus the battery capacity; determining the gradient of the resultant eddy current signal versus the battery capacity; determining the deviation of the ultrasonic signal gradient for the battery being diagnosed from the average gradient value preliminary obtained on the training sample of batteries; determining the deviation in the gradient of the resultant eddy current signal for the battery being diagnosed from the average gradient initially obtained on the training sample set of batteries; forming the probability density functions for the deviations of the eddy current resultant signal obtained in the initial state of the battery, and the gradients of the ultrasonic and eddy current resultant signals; forming of binary signals for the deviations of the eddy current resulting signal obtained in the initial state of the battery, and the gradients of the ultrasonic and eddy current resultant signals while using corresponding thresholds; determining the probabilities of the obtained binary signals for the battery being diagnosed using corresponding probability density functions; rejecting the batteries being diagnosed while using the obtained binary signals with their probability values and a logical rule set.