Electrical Testing on Prismatic Battery Cells

Example of testing machines for prismatic cells:

An extremely compact bench, predisposed to be used as stand-alone testing station or to be automatically loaded by robot. It is a configuration particularly suitable for use in pilot lines, or for production lines with low-medium rates. Different solutions can be proposed for mass production.

Being based on a turning table, the cells are loaded by an operator or an automatic system ensuring the safest working conditions.

The arrangement of the cell nest is punctually determined, in terms of number and shape, according to specific cell model and size.

The number of nests (up to eighteen) guarantees the autonomy of the machine and the operator interaction.

After the identification of the cell, the preliminary measurement is the dimensional assessment.

A dedicated gripper, actuated by a servocontrolled two-axis manipulator, acquires the thickness of the cell in different contact points along the body of the cell itself. Number and position of the measuring points can be freely programmed according to customer’s requirements.

The main station is dedicated to the electrical testing, where pogo-pin device closes the circuit between anode and cathode with a controlled force.

Different measurements can be performed, according to customer’s specifications:

• Open Circuit Voltage (OCV);
• Alternate Current Internal Resistance (ACIR-1kHz);
• Direct Current Internal Resistance (DCIR);
• Electrochemical Impedance Spectroscopy (EIS).

The last testing station is dedicated to check the perfect insulation of the external enclosure (HV test or High Voltage Insulation test).

A conductive foam is adopted as diffuse contact element of the system, to guarantee the complete examination of the sides of the whole external surface.