New Test Spots Lithium-Ion Battery Flaws

A new thermal imaging tool can find tiny defects in lithium-ion electrodes as they are being manufactured, according to researchers at Purdue University.

They say identifying such flaws during the production process could lead to improved battery life and reliability.

The Purdue process uses flash thermography to spot inconsistencies in the thickness of "battery paint," a material applied to one side of a copper electrode.

The coating a blend of carbon, lithium-holding particles, chemical binders and carbon black expands as it captures ions and contracts when it releases them. Such cycling, which occurs as the battery is charged and discharged, causes mechanical stress in unevenly applied paint that eventually damages the cell.

The Purdue process uses a flashing xenon bulb to heat the uncoated copper side of the electrode. A thermal camera measures heat flow through the opposite side. The researchers say measurements take less than one second.

The system can detect variations in coating thickness of only a few percentage points, according to the developers. They say a 1 shift in temperature approximately equates to a 1% difference in the thickness of the battery paint.

The Purdue team will present a research paper on its work during the 2013 annual meeting of the Society for Experimental Mechanics on June 3-5 in Lombard, Ill.