Experimental and Numerical Investigation of the Thermal Performance of a Hybrid Battery Thermal Management System for an Electric Van
The temperature and the temperature gradient within the battery pack of an electric vehicle have a strong effect on the life time of the battery cells. In the case of automotive applications, a battery thermal management (BTM) system is required to maintain the temperature of the cells within a pres...
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| Format: | Article |
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MDPI AG
2021-04-01
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| Series: | Batteries |
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| Online Access: | https://www.mdpi.com/2313-0105/7/2/27 |
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| author | Franck Pra Jad Al Koussa Sebastian Ludwig Carlo M. De Servi |
| author_facet | Franck Pra Jad Al Koussa Sebastian Ludwig Carlo M. De Servi |
| author_sort | Franck Pra |
| collection | DOAJ |
| description | The temperature and the temperature gradient within the battery pack of an electric vehicle have a strong effect on the life time of the battery cells. In the case of automotive applications, a battery thermal management (BTM) system is required to maintain the temperature of the cells within a prescribed and safe range, and to prevent excessively high thermal gradients within the battery pack. This work documents the assessment of a thermal management system for a battery pack for an electric van, which adopts a combination of active/passive solutions: the battery cells are arranged in a matrix or composite made of expanded graphite and a phase change material (PCM), which can be actively cooled by forced air convection. The thermal dissipation of the cells was predicted based on an equivalent circuit model of the cells (LG Chem MJ1) that was empirically calibrated in a previous study. It resulted that, in order to keep the temperature of the battery pack at or below 40 °C during certain charge/discharge cycles, a purely passive BTM would require a considerable amount of PCM material that would unacceptably increase the battery pack weight. Therefore, the passive solution was combined with an air cooling system that could be activated when necessary. To assess the resulting hybrid BTM concept, CFD simulations were performed and an experimental test setup was built to validate the simulations. In particular, PCM melting and solidification times, the thermal discrepancy among the cells and the melting/solidification temperatures were examined. The melting time experimentally observed was higher than that predicted by the CFD model, but this discrepancy was not observed during the solidification of the PCM. This deviation between the CFD model results and the experimental data during PCM melting can be attributed to the thermal losses occurring through the mock-up casing as the heating elements are in direct contact with the external walls of the casing. Moreover, the temperature range over which the PCM solidifies was 6 °C lower than that estimated in the numerical simulations. This occurs because the simple thermodynamic model cannot predict the metastable state of the liquid phase which occurs before the onset of PCM solidification. The mockup was also used to emulate the heat dissipation of the cells during a highway driving cycle of the eVan and the thermal management solution as designed. Results showed that for this mission of the vehicle and starting from an initial temperature of the cells of 40 °C, the battery pack temperature could be maintained below 40 °C over the entire mission by a cooling air flow at 2.5 m/s and at a temperature of 30 °C. |
| first_indexed | 2024-03-10T11:51:48Z |
| format | Article |
| id | doaj.art-1c6d3bf1f75e42d7ac3d442512a10bf6 |
| institution | Directory Open Access Journal |
| issn | 2313-0105 |
| language | English |
| last_indexed | 2024-03-10T11:51:48Z |
| publishDate | 2021-04-01 |
| publisher | MDPI AG |
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| series | Batteries |
| spelling | doaj.art-1c6d3bf1f75e42d7ac3d442512a10bf62023-11-21T17:35:12ZengMDPI AGBatteries2313-01052021-04-01722710.3390/batteries7020027Experimental and Numerical Investigation of the Thermal Performance of a Hybrid Battery Thermal Management System for an Electric VanFranck Pra0Jad Al Koussa1Sebastian Ludwig2Carlo M. De Servi3CEA LITEN, F-38054 Grenoble, FranceUnit Energy Technology, VITO, Boeretang 200, BE-2400 Mol, BelgiumInstitute for Electrical Energy Storage Technology, Technical University of Munich (TUM), Arcisstr. 21, 80333 Munich, GermanyUnit Energy Technology, VITO, Boeretang 200, BE-2400 Mol, BelgiumThe temperature and the temperature gradient within the battery pack of an electric vehicle have a strong effect on the life time of the battery cells. In the case of automotive applications, a battery thermal management (BTM) system is required to maintain the temperature of the cells within a prescribed and safe range, and to prevent excessively high thermal gradients within the battery pack. This work documents the assessment of a thermal management system for a battery pack for an electric van, which adopts a combination of active/passive solutions: the battery cells are arranged in a matrix or composite made of expanded graphite and a phase change material (PCM), which can be actively cooled by forced air convection. The thermal dissipation of the cells was predicted based on an equivalent circuit model of the cells (LG Chem MJ1) that was empirically calibrated in a previous study. It resulted that, in order to keep the temperature of the battery pack at or below 40 °C during certain charge/discharge cycles, a purely passive BTM would require a considerable amount of PCM material that would unacceptably increase the battery pack weight. Therefore, the passive solution was combined with an air cooling system that could be activated when necessary. To assess the resulting hybrid BTM concept, CFD simulations were performed and an experimental test setup was built to validate the simulations. In particular, PCM melting and solidification times, the thermal discrepancy among the cells and the melting/solidification temperatures were examined. The melting time experimentally observed was higher than that predicted by the CFD model, but this discrepancy was not observed during the solidification of the PCM. This deviation between the CFD model results and the experimental data during PCM melting can be attributed to the thermal losses occurring through the mock-up casing as the heating elements are in direct contact with the external walls of the casing. Moreover, the temperature range over which the PCM solidifies was 6 °C lower than that estimated in the numerical simulations. This occurs because the simple thermodynamic model cannot predict the metastable state of the liquid phase which occurs before the onset of PCM solidification. The mockup was also used to emulate the heat dissipation of the cells during a highway driving cycle of the eVan and the thermal management solution as designed. Results showed that for this mission of the vehicle and starting from an initial temperature of the cells of 40 °C, the battery pack temperature could be maintained below 40 °C over the entire mission by a cooling air flow at 2.5 m/s and at a temperature of 30 °C.https://www.mdpi.com/2313-0105/7/2/27phase changing materialelectric vehiclebattery thermal management |
| spellingShingle | Franck Pra Jad Al Koussa Sebastian Ludwig Carlo M. De Servi Experimental and Numerical Investigation of the Thermal Performance of a Hybrid Battery Thermal Management System for an Electric Van Batteries phase changing material electric vehicle battery thermal management |
| title | Experimental and Numerical Investigation of the Thermal Performance of a Hybrid Battery Thermal Management System for an Electric Van |
| title_full | Experimental and Numerical Investigation of the Thermal Performance of a Hybrid Battery Thermal Management System for an Electric Van |
| title_fullStr | Experimental and Numerical Investigation of the Thermal Performance of a Hybrid Battery Thermal Management System for an Electric Van |
| title_full_unstemmed | Experimental and Numerical Investigation of the Thermal Performance of a Hybrid Battery Thermal Management System for an Electric Van |
| title_short | Experimental and Numerical Investigation of the Thermal Performance of a Hybrid Battery Thermal Management System for an Electric Van |
| title_sort | experimental and numerical investigation of the thermal performance of a hybrid battery thermal management system for an electric van |
| topic | phase changing material electric vehicle battery thermal management |
| url | https://www.mdpi.com/2313-0105/7/2/27 |
| work_keys_str_mv | AT franckpra experimentalandnumericalinvestigationofthethermalperformanceofahybridbatterythermalmanagementsystemforanelectricvan AT jadalkoussa experimentalandnumericalinvestigationofthethermalperformanceofahybridbatterythermalmanagementsystemforanelectricvan AT sebastianludwig experimentalandnumericalinvestigationofthethermalperformanceofahybridbatterythermalmanagementsystemforanelectricvan AT carlomdeservi experimentalandnumericalinvestigationofthethermalperformanceofahybridbatterythermalmanagementsystemforanelectricvan |