# Lithium ion battery immerse cooling

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• Last Post 16 March 2020
Balakumaran posted this 11 March 2020

Good afternoon to all. I am B.E.automobile final year student ,now I am currently doing my final year project about immerse cooling of 18650 cylindrical lithium ion cell. The cell temperature is 80 °C at 5 C discharge current so I should keep the cell temperature range between 20-40° C. I would like to share my little bit confusion to all for clarifying my confusion. Assume there is an one hollow rectangular box which is filled up by water liquid and also lithium ion cell covered by cylindrical aluminium 2mm thickness for prevent from short circuit. The hollow square box dimensions : (28 length * 28 width ) in mm ,Height is 64 mm , thickness is 4 mm. The lithium ion cell is 18 mm diameter ,height is 65 mm and it is covered by aluminium (24mm dia) for prevent from short circuit. Now The cell is around the water inside the hollow square box. The cell of thermal properties is , Thermal conductivity = 3.9 W/mK, Specific heat capacity = 2900 J/kgK, Density = 1000 kg/m³. The glycol is picked up from engineering data source. The rectangular box is aluminium picked up from the engineering data source. I have done this problem in steady state analysis ,but the temperature of the lithium ion battery could not decreases. And Also I have done it in transient thermal analysis ,the problem results wrong and the out come was not good . How to choose the some inputs and outputs in analysis such as initial temperature , convection , temperature and so on Experts,Staffs,teachers, students,and so on could you please help me for this problem(from 80°C of cell to 20-40°C). Thanks lot all.

rwoolhou posted this 13 March 2020

Check you did the share topology operation correctly otherwise the heat won't pass between bodies. The other common oversight is that you need temperature dependent density & gravity to model buoyancy effects.

As a suggestion, make a very simple model (hot solid in a fluid zone) and understand how to make that work.

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Balakumaran posted this 13 March 2020

Thank you for your reply, I am beginner to thermal analysis ,could you tell me that how to give boundary conditions of hot solid in a fluid region

rwoolhou posted this 16 March 2020

Use a source term, and go through the tutorials that are available through "Help".