To enhance the lithium-ion battery pack's operating performance while it is continuously used at varying charge rate and higher ambient temperatures, the current research proposes a thermal management system composed of a phase change material with a passive metallic connection. Along with constant charge rate of 1C, 2C and 3C rate, battery pack also investigated at harshest 4C rate condition, to check its thermal performance. In total, three configurations are investigated: configuration 1 has no passive cooling arrangement, configuration 2introduces a passive thermal design with a phase change material submerged cooling technique that includes paraffin wax and extended graphene composite phase change material, and configuration 3is a proposed improved thermal design in which a graphene-enhanced high thermal conductive metallic separator is coupled at the PCM wall to increase PCM temperature delay efficiency. A phenomenon of inefficient thermal performance is observed for typical pure PCM form due to its lower thermal conductivity and heat transfer rate, resulting in a loss of capacity to cause temperature delay effect in battery pack. In proposed improved model of having metallic separator at wall of PCM results shows, none of the case had exceeded effective battery temperature limit of 55°C and liquid fraction rate of PCM and EG CPCM remained below liquidious point which allows it to deliver more temperature delay effect. Comparative performance study between paraffin wax PCM and EG CPCM suggest EG CPCM is able to provide more delay effect due to its thermophysical property advantage of higher thermal conductivity and greater heat transfer performance. 

Novel metallic separator coupled composite phase change material passive thermal design for large format prismatic battery pack

Computational study of PCM cooling for electronic circuit of smart-phone

In the modern scenario of the automobile industry there is a translation from conventional fuel vehicles to electric vehicles as a set to reduce carbon percentage. High power Lithium-ion batteries are the main power source of this vehicle to drive the powertrain, but due to the natural influence of various hot environmental conditions, there is a significant reduction in mileage of vehicle which is not desirable because a lithium-ion battery pack covers 50 to 60% whole cost of vehicle. To tackle this problem from recent years there are several types of research have been performed over active and passive thermal management techniques in which passive thermal management system is widely growth from recent years due to its numerous working advantages with the low-cost application. In the present study, we performed PCM based passive thermal management study over 60 Cell 18,650 Lithium-ion battery packs which are considered to be working for automobile applications. The high-power energy density battery is submerged with a layer of PCM to investigate the delay effect caused by the battery pack to resists the set limit of the threshold temperature range. The output field results from numerical investigation are predicted using neural network approach in which a multi-objective optimization strategy is proposed between battery pack delay effect for selected paraffin wax and RT-18 PCM against its given C-rate. furthermore, liquid fraction rate is monitored for the fixed temperature limit in varying C-rate condition, for optimization strategy Fixed temperature is taken as a function for time delay by PCM addition with liquid fraction rate of PCM over the varying C-rate condition. Correlations suggest paraffin wax is the best choice for a set temperature limit below 60 °C because paraffin wax is found to be melted faster and acts as a resistance to increase the temperature of the cell. The best fit line from the linear regression model using neural network approach suggest best fit line as the time delay is the function of liquid fraction rate over the selected PCM configuration. The highest time delay is occurred in case of paraffin wax PCM as 11,900 s for 1C rate and lowest time delay is occurred as 10,000 s for 1C rate in case of RT-18.

Phase change material based passive battery thermal management system to predict delay effect

• It was observed that the presence of PCM is not always advantageous. • The presence of PCM can only be useful if the PCM undergoes phase changes. • PCM effectiveness in thermal control unit (TCU) depends on convection coefficient (h). • At h = 5 W m 2 . K , the battery temperature dropped by 8 °C due to the PCM presence. • At 20 W m 2 . K battery temperature was increased by 4.8 °C when PCM was loaded into TCU. Keeping cool the lithium-ion battery improves its performance. In this study, focusing on battery cooling, a thermal control unit (TCU) containing metal fins was integrated into the battery. To boost TCU effectiveness, phase change material (PCM) was injected into it. By numerical solution, the temperature distribution in three areas of battery, fins and PCM was determined. Using Fourier's law, TCU heat dissipation to the environment was evaluated at different convection coefficients (5, 10, and 20 W m 2 . K ). It was observed that the presence of PCM is not always advantageous. The presence of PCM can only be useful if the PCM undergoes phase changes. This happened at 5 W m 2 . K , and at best conditions, the battery temperature dropped by 8°C due to the PCM presence. After the melting process, the PCM presence significantly augmented the battery temperature. At 20 W m 2 . K battery temperature was increased by 4.8 °C when PCM was loaded into TCU. Therefore, adding PCM to TCU with convection coefficient is not recommended. Increasing the number of fins declined the battery temperature. If the number of fins increases from three to five, the battery cooled by 1 to 1.7°C at convection coefficient range of 5–20 W m 2 . K 

Challenges in incorporating phase change materials into thermal control units for lithium-ion battery cooling

In the view of the thermal runaway scenario phase change material are not capable to withstand thermal propagation phenomenon, hence it is important to provide a novel structure which can delay thermal runaway trigger point and not allows generated heat to propagate at faster rate from one cell to another. In this work, a series of numerical investigations are performed from cell to pack level configuration under heater assisted triggering method by providing a constant heat supply of 500 W until electrochemical kinetics of cell gets trigger. This setup is used to investigate, time delay and thermal propagation phenomenon by integrating submerged layer of phase change material. Conclusive evidence from investigation suggests that by integrating a submerged layer of phase change material, the thermal runaway trigger point can be effectively delayed. However, because phase change material is highly flammable in nature, heat propagates from one cell to another in a very short period, causing the entire pack to go into catastrophic thermal failure within short span of 10s. To delay this thermal propagation phenomenon and compliance GB 38031 and GB 38032 “national safety regulation of battery pack for Electric Bus and Electric Vehicle” that suggest once cell is trigger, neighbouring cell should not run in thermal runaway for at least 300s, we have optimized battery pack structural design by introducing low thermal conductive pyro liner at the wall of PCM. Results showed, this optimize design represents dual functionality of delaying thermal runaway trigger point of cell along with slowing down thermal propagation for at least 800s. 

Battery thermal runaway propagation time delay strategy using phase change material integrated with pyro block lining: Dual functionality battery thermal design

The current study deals with the numerical investigation of the substrate board characteristics using different materials (FR4, silicon cladding and copper cladding) on which nine nonidentical elec...

Effect of thermal conductivity of substrate board for temperature control of electronic components: A numerical study

The aim of this paper is to provide an implicit transient numerical formulation of novel minichannel-coupled passive thermal arrangement to cool down unidentical IC chips on substrate board. In the proposed design, PCM is integrated in the minichannel which is kept at the periphery of IC chips. Through means of direct conduction from substrate board, phase change material absorbs latent heat and allows it to change its phase from solid to liquid by providing effective thermal cooling performance in system. A comparative study is developed between without PCM, with minichannel-coupled PCM and optimized single minichannel near the heat source. Results show that between paraffin wax, N-Eicosane and ATP 78 PCM, N-Eicosane can provide effective cooling performance. With the N-Eicosane temperature in the system controlled from 53.234 ∘ C of the generic model to 51.520 ∘ C and a significant 1.74 ∘ C of temperature drop compared with the generic model, an additional 0.5 ∘ C of temperature reduction occurs as compared with the case of paraffin wax PCM and 1.35 ∘ C when compared with ATP 78 PCM. 

Anant Sidhappa Kurhade

Papers

Computational study of PCM cooling for electronic circuit of smart-phone

Effect of thermal conductivity of substrate board for temperature control of electronic components: A numerical study

Thermal Control of IC chips using phase change material: A CFD Investigation

CFD Approach for Thermal Management to Enhance the Reliability of IC Chips