Experimental and numerical investigation of core cooling of Li-ion cells using heat pipes

• Presents experimental results on cooling of Li-ion cell using embedded heat pipe.
• Addresses the important technological challenge of cooling the core of the cell.
• Compares heat pipe performance with other cooling approaches.
• Shows that a solid metal rod may be equally effective as a heat pipe.
• Shows that a heat pipe successfully prevents overheating due to malfunction.

While Li-ion cells offer excellent energy conversion and storage capabilities for multiple applications, including electric vehicles, heat removal from a Li-ion cell remains a serious technological challenge that directly limits performance, and poses serious safety concerns. Due to poor thermal conductivity of Li-ion cells, traditional cooling methods like air cooling on the cell surface do not effectively access and cool the core. This may lead to overheating of the cell core. This paper investigates the cooling of Li-ion cells using an annular channel through the axis of the cell. Air flow through this channel and heat pipe insertion are both shown to result in effective cooling. A temperature reduction of 18–20 °C in the cell core is observed in heat pipe experiments, depending on heat pipe size, for 1.62 W heat dissipation. Similar effect is observed when a thin metal rod is used instead of a heat pipe. Experimental measurements are close to finite-element simulation results. Experiments demonstrate that a heat pipe successfully prevents overheating in case of sudden increase in heat generation due to malfunction such as cell shorting. This paper illustrates fundamental thermal-electrochemical trade-offs, and facilitates the development of novel and effective cooling techniques for Li-ion cells.