Batteries could power and cool chips, say Zurich researchers

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Chip stacks could be supplied with electrical power by integrated flow batteries and cooled at the same time, according to research undertaken by ETH Zurich and IBM Research Zurich.

In flow batteries, electricity is produced by an electrochemical reaction between two liquid electrolytes which are pumped into the battery cell through a closed loop. By using liquids that are suitable for use as flow-battery electrolytes and for cooling, heat can be dissipated using the same circuit.

“The chips are effectively operated with a liquid fuel and produce their own electricity,” said ETH Professor Dimos Poulikakos.

The concept is to assemble chip stacks layer by layer – a computer chip, then a thin battery to supply the chip with electricity and cool it, then another chip and so on.

As part of this work, the team has built a 1.5mm thick battery that generates 1.4W/cm2. After subtracting the power required to pump the liquid electrolytes to the battery, the net power density is 1W/cm2.

The team showed in an experiment that electrolyte liquids can not only cool a chip, but also dissipate many times more heat than the battery generates as electrical energy.

The electrochemical reactions in the battery occur in two thin, porous electrode layers separated by a membrane. 3D printing technology was used to build a polymer channel system to press the electrolyte liquid into the porous electrode layer as efficiently as possible. The most suitable of the designs tested proved to be wedge shaped convergent channels.

However, although the battery’s power density is high, the amount of electricity produced is not enough to power a chip and the team are looking to industrial partners to optimise the design.