Through-transmission eddy current system for inline inspection of power source electrodes

An eddy current non-destructive evaluation system for an electrode film material, the system comprising:

• at least one control module configured to generate a transmission signal;
• a first pair of coils comprising
• a first coil disposed adjacent the electrode film material and configured to operate in a transmit mode, and, based on the transmission signal, to generate an electromagnetic field that passes through the electrode film material, and
• a second coil disposed adjacent and on an opposite side of the electrode film material as the first coil and configured to operate in a receive mode, wherein the second coil is configured to generate a first electromagnetic field voltage based on the electromagnetic field, and
• wherein the at least one control module is configured, based on the first electromagnetic field voltage, to at least one of determine a first thickness of the electrode film material and detect a defect of the electrode film material;
• and
• a second pair of coils comprising
• a third coil disposed adjacent the electrode film material and configured to operate in a transmit mode, and, based on the transmission signal, to generate an electromagnetic field that passes through the electrode film material, and
• a fourth coil disposed adjacent and on an opposite side of the electrode film material as the third coil and configured to operate in a receive mode, wherein the fourth coil is configured to generate a second electromagnetic field voltage based on the electromagnetic field generated by the third coil;
• and
• a first multiplexer configured to select between the second coil and the fourth coil,
• wherein the at least one control module is configured to control a state of the first multiplexer, and to determine a second thickness based on the second electromagnetic field voltage.

An eddy current non-destructive evaluation method for electrode film material, the method comprising:

• generating a transmission signal;
• operating a first coil, disposed adjacent the electrode film material, in a transmit mode, and, based on the transmission signal, to generate an electromagnetic field that passes through the electrode film material;
• operating a second coil, disposed adjacent and on an opposite side of the electrode film material as the first coil, in a receive mode, and to generate a first electromagnetic field voltage based on the electromagnetic field;
• based on the first electromagnetic field voltage, at least one of determining a first thickness of the electrode film material and detecting a defect of the electrode film material;
• based on the transmission signal, generating a drive signal to drive the first coil, and generating a reference signal proportional to the drive signal;
• downconverting the reference signal to a downconverted reference signal;
• downconverting a receive signal to a downconverted receive signal;
• generating via the second coil the receive signal including the first electromagnetic field voltage;
• and
• determining the first thickness based on the downconverted reference signal and the downconverted receive signal.