40 current standards necessitate the use of composite materials with temperature ratings exceeding 105 C. The existing limits of IEC 62196 and UL2251 are based on old, material limits that specified a maximum temperature limit of 90 C; 100 C was agreed as a compromise to provide a design margin below the materials limit of 105 C. Commonly used composite plastics can be found in high-temperature grades with relatively higher working temperatures. These grades of plastic are not prohibitively expensive and would allow for a contact temperature increase while remaining within working limits. Short-circuit protection The larger battery packs of heavy duty systems mean that the prospective short-circuit currents from multiple battery packs, as available at the vehicle inlet, should be limited by the vehicle to a peak current of 70 kA and 12 MA²s. The most important factor for the voltage is to support as many vehicles as possible while balancing this with the total operating range. Alternatives were considered, such as reduced operating performance with higher/lower voltages needed due to unique operating modes or battery cell chemistries. MCS should use a minimum voltage of 500 VDC and a maximum voltage of 1250 VDC. While this will not cover all of the possible use cases of every vehicle type, this is expected to provide a good compromise between operating voltage range and vehicle coverage, with the connector designed for 1500 VDC. The recommended MCS retention is based on the lessons of the consumer’s CCS connector. The MCS interface includes an electrically activated/ actuated lock to ensure the connector remains engaged with the inlet during normal operation, and in case of a short circuit. This electrically activated retaining means shall provide feedback to the EV and be controlled independently of the buttons or switches used for normal user-requested shutdowns or emergency shutdowns. The retaining means shall be integrated into the inlet side of the MCS coupler on at least one location, and up to three. The lock shall have a pin or slot design that operates consistently in all expected operating conditions. The distance from the SECC to the EVCC is critical for stable, high-level communications. As communication cable lengths of up to 17 m (15 m outside vehicle plus 2 m inside vehicle) are expected, and the site layout and charging connector locations also consider a maximum cable length of 15 m, CharIN recommends 15 m at most. For liquid-cooled cables, it is recommended to keep lengths as short as possible to avoid excessive performance requirements on the cooling system and manual handling of the cable. The charging inlet position on heavy duty vehicles and the charge-bay layout should therefore be standardised. MCS is a newly developed charging interface and system that will continue to evolve as it becomes increasingly more technically detailed. Acknowledgements With thanks to John Warner at American Battery Solutions and Felix Nelius at Freudenberg FEPS. Focus | Battery tech for heavy-duty apps July/August 2024 | E-Mobility Engineering Some suppliers of battery tech for heavy-duty apps American Battery Solutions +1 248 462 6364 www.americanbatterysolutions.com ABB - www.abb.com Alpha Motors - www.alphamotorsinc.com Atlas Copco +1 949 393 0548 www.atlascopco.com Dannar +1 765 216 7191 www.dannar.us.com Electrovaya +1 905 855 4618 www.electrovaya.com Eleo +31 492 25 10 www.eleo.tech Freudenberg e-Power Systems +49 6201 80 0 www.freudenberg.com Janus Electric - www.januselectric.com.au Proterra +1 864 438 0000 www.proterra.com Proventia +358 50 4088 142 www.proventia.com Sandvik +46 8 456 11 00 www.sandvik.com Webasto +49 898 57 940 www.webasto.com High-power charging for construction equipment (Image courtesy of Atlas Copco)
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