1st ICAI 2020

International Conference on Automotive Industry 2020

Mladá Boleslav, Czech Republic

temperature range of 20‒40 °C. Manufacturing a battery with such a design does not require a sophisticated technological base and therefore can be a cheaper yet sufficient solution for selected applications. Figure 4: left: Design concept of battery with 14 cell modules without thermal management system. right: Sample of single module electronic battery management system

Source: own elaboration (2019)

The second battery design approach assumes the use of all currently known state-of-the- art technologies. 21700nominal size cylindrical cells with rated energy of 18.2Wh@750 Wh·l -1 has been chosen to achieve the highest possible energy density at the cell level. This modern format delivers the same energy density as a widely used 18650 size with about 30 % more energy stored. As a result, fewer cells are used to manufacture the battery modules with the benefit of less potentially problematic cell connections. The ability to transfer heat form cell surface to the coolant and vice versa is not significantly impaired by the transition to this bigger size cell. However, cells with the highest energy density lack overall robustness. In order to maximize the life of the battery due to frequent rapid charging, the design of the battery is dealing with the use of another trend so called “flooded” battery. Thus, the cells are either fully or for the most part immersed in a dielectric coolant fluid of specific properties. This technology, coupled with small cylindrical cell size, enables the highest pack level assembly efficiency in conjunction with the most efficient temperature management and increased safety in case of battery damage. The platform itself will be equipped with a powerful heating element and a thermal management system using the waste heat of the other components of the platform. To maximize efficiency, the heat pump can be added into to the platform onboard coolant circuit, or the coolant fluid conditioning unit of the charging station can be used. The coolant circuit of charging station will be connected with the platform via charging connector. Advanced battery management system will use the adjustable voltage control (Paryani et al., 2015) and asymmetric temperature modulation (Yang et al., 2019) charging algorithms for enabling ultra-fast charging.

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