Integration and testing of next generation post-800V electric powertrains (2ZERO Partnership)

Next generation powertrain architectures using voltages 1200 V and above might contribute to the achievement of safer, higher-performing and more sustainable end products to serve high volume markets. A holistic approach to the whole powertrain should contribute to determining the optimal next generation voltage level. Project results are expected to contribute to all the following outcomes:

• Very fast charging, ultra-efficient electric vehicles (EVs) for broad mass markets, taking into account volume effects and cost optimized architectures for future markets.
• A cost reduction of a minimum of 20% of power electronic modules and inverters for a given power, as well as for the whole powertrain, should be demonstrated (in comparison to the cost of the best current-generation or close to market components and architectures at proposal submission time).
• Fast charging of a mass market C segment vehicle demonstrator from 20 to 80 percent in 10 minutes with currently available 350kW chargers.
• Practical range increases over travel time (~20 percent increase with the same battery weight) with overall higher efficiency and easier thermal management of the whole powertrain allowing reasonably sized, lower cost and environmentally friendly batteries to perform long trips conveniently.
• Significant advancements in efficiency (reduction of losses by 25%) versus the state of the art of the targeted application with a special attention to partial load condition in EVs and charging stations alike.
• Backwards compatibility and reliability aspects.
• Improved application safety and robustness that contribute to a better user buy-in.
• Improved resource efficiency with better lifecycle impact and recycling capability ¬ contributing to a circular economy approach.

In the last decade, the more and more demanding power and application requirements led to an increase of board net HV voltage from an initial 400V level to 800V in the latest electric vehicles, already trickling down to lower categories. Significantly higher voltages (indicatively, in the 1200V region) may be the next logical step and become standard in the next decade, providing benefits in terms of efficiency, copper use and weight. If not properly managed, they could have a constraining impact on the overall architecture especially in terms of DC charging and efficiency for low power use. Thus, new challenges for the powertrain arise in the areas of the motor, battery, cabling, couplers etc. as well as in electromagnetic compatibility and the development and integration of new power semiconductors.

To successfully address the expected outcomes in the constant drive to improve efficiency and performance while increasing affordability, proposals are expected to address several of the following aspects capable of demonstrating the achievement of the intended objectives at system level:

• Assess in a holistic way the positive and negative impacts of higher voltage levels at vehicle and powertrain level, defining the best option for the post-800V EV generation.
• Development and integration of power-electronic components with new concepts for component miniaturisation and modularity. Also, solutions that can transition rapidly from modular to integrated systems need to be identified, depending on demand and eco-balance.
• Topologies adapted to advanced wide-bandgap semiconductors and new materials, leading to higher power density.
• Modular powertrain platforms, with the aim of coming closer to a full mechanical, electrical or thermal integration of the three main systems (electric motor, power electronics systems and battery pack) benefitting from the smaller sizes and cooling demands due to higher voltage.
• Defining suitable testing and validation procedures on component, powertrain or vehicle level and demonstrating them on a suitable use case. Furthermore, the projects should identify and analyse potential regulatory aspects and barriers to contribute to a definition of common EU standards for system validations.
• Small-sized, ‘ready for integration’ power modules at the best system fitting position (e.g. e-motor or battery) for greater design flexibility while optimizing costs.
• Packaging and coupler solutions e.g., substrates, moulding epoxy, electrical interconnections, adapted for higher voltages, increased isolation demands, high-frequency switching, frequent thermal cycling, elevated temperatures etc.
• Heat spreading technologies for short power pulses/ heat dissipation approaches for long duration pulses, long acceleration phases.

Exploitation of outcomes, and knowledge from ECSEL/KDT partnership^[1] projects should be foreseen where applicable, as well as feedback in terms of future needs to achieve the project outcomes should problems be encountered. The development of the needed semiconductors, however, is not part of this topic's funding, and the proposal is expected to specify the components that the involved semiconductor suppliers guarantee to provide for the research activities.

This topic implements the co-programmed European Partnership on ‘Towards zero emission road transport’ (2ZERO). As such, projects resulting from this topic will be expected to report on the results to the European Partnership ‘Towards zero emission road transport’ (2ZERO) in support of the monitoring of its KPIs.

Activities are expected to achieve TRL 5 by the end of the project – see General Annex B.

[1] https://www.kdt-ju.europa.eu/