Key Objectives

This objective will be achieved through smart combination and implementation of the following innovations:

a.    Use of novel nickel-rich, prismatic battery cells with an energy density of ≥250 Wh/kg;

b.    Improved and efficient thermal management system for improved cell temperature control:

    • by applying immersion cooling, replacing the present bottom cooling, to achieve homogeneous cooling of the cells;
    • by using a dielectric phase-changing material – as one of the immersion cooling components – to achieve nearly perfect homogenous cooling all around the battery cells (target is max. temperature variation of 2◦C);
    • by optimising the functioning of the whole cooling loop for driving and fast charging requirements resulting in a higher cooling capacity of 12-15 kW (instead of 6-8 kW) and with a limited volume increase.

c.    Optimal cell arrangement in the battery pack (cell-to-pack) to reduce volume and weight or to maximise the battery capacity for the same volume;

d.    Implementation of a lightweight housing of composites or fibre-reinforced plastic replacing the heavy metal housing of the present battery pack without jeopardising the safety requirements;

e.    Increased operating voltage of the battery system from the present 400 V to 800 V to reduce power losses on the current conductors and reduce overall cabling/copper plates weight and cost;

f.     Implementation of a lightweight semiconductor-based main switch replacing the heavy conventional solution;

g.    Improved BMS including novel state estimators for improved control and utilising a larger SoC (State-of-Charge) window within the safety limits.

Integrating all of the above will lead to a compact battery pack with a capacity of 96 kWh and weight of 520 kg. This should lead to a range of at least 500 km which represents a 20% improvement. Further increases in the achievable range would require modifications related to vehicle development (e.g. vehicle aerodynamics, auxiliaries’ consumption, etc.), which are definitely out of the scope of LIBERTY.

This objective will be achieved through a smart combination and implementation of the following innovations:

a.    Improvement of the thermal management system to enable high-power charging up to 350 kW instead of 150 kW (see Objective 1b for innovations)

b.    Improved BMS, allowing for a higher average charging power within the safety limits:

    • by applying novel and robust algorithms and diagnostics for SoC, SoH (State-of-Health), SoF (State-of-Function) allowing enriched monitoring functions to minimise accelerated battery ageing through advanced battery charging control strategies;
    • by enhancing the measurement capabilities in terms of accuracy and speed for measuring cell voltages, string current and temperatures inside the battery pack, while allowing synchronous measurement of voltage and current, to detect any battery cell anomalies caused by fast charging in an early stage.

c.    Increased operating voltage of the battery system from the present 400 V to 800 V to reduce current requirements on EV charging stations.

Integrating these innovations will lead to the capability of high-power charging at 350 kW over a wide SoC and temperature range. This should lead to a charging time of less than 20 minutes based on 96 kWh (70% Δ SoC). This is less than half the charging time compared to the state-of-the-art.

Jointly, key objectives 1 and 2 will relax range anxiety and will enable long duration trips (e.g. 700-1000 km day trips across different Member States) under the condition that fast-charging infrastructure is available along the route.

This objective will be achieved through a smart combination and implementation of the following innovations:

 a.    Improvement of the crashworthiness of the battery pack:

    • Through proper design of the battery system taking the safety requirements into consideration;
    • By reinforcement of the battery housing with carbon or glass fibres, to improve crash protection and also provide resistance to fire and thermal propagation;
    • By integration of a semiconductor-based battery main switch, which prevents electrical currents due to mechanical issues in case of severe damage to the battery.

b.    Secure protection against a thermal runaway through lowering the probability of occurrence:

    • By preventing the transfer of thermal runaway from one cell to neighbouring cells by implementation of an active safety system using thermal fuse materials;
    • By integration of newly developed pressure sensors into the battery casing to enable pressure regulation and enhance safety measures;
    • By advancing the SoH, SoC, SoF and SoS (State-of-Safety) state estimations to max 3% error by means of artificial intelligence (AI) techniques;
    • By improving measurement capabilities of the BMS and using these novel measurements for early detection of internal cell defects;
    • By applying cross-training strategies on a BMS which monitors the battery system’s real-time data and compares it with data repositories in the cloud (of the own vehicle battery pack and that of similar vehicle battery packs), thus avoiding operating conditions which may have led to potentially harmful safety events.

c.    Improvement of the safety requirements:

    • By development of advanced and relevant procedures and protocols for battery safety-related testing on crashworthiness, thermal runaway and functional safety level, for improved battery and passenger safety beyond standard operational conditions (accident, functionality problem, etc).

Combining all mentioned innovations will lead to a battery system that is well resilient against thermal runaway events and has high crashworthiness characteristics.

This objective will be achieved through a smart combination and implementation of the following innovations:

a.    By implementation of an improved thermal management system (see objective 1b). This ensures more accurate and homogeneous temperature control of the battery cells under all conditions incl. fast charging;

b.    Improved BMS and advanced state estimation algorithms (both see objective 2b) for early failure detections and prevention;

c.    By a battery passport containing relevant data from the first life use case which may contribute to decide the most appropriate second life use of the battery, thus extending the total battery lifetime;

d.    By applying cross-training strategies on AI-based algorithms (see objective 3b) through combining and using input data from various vehicles and fleets, and their corresponding battery passport data to avoid operating conditions recorded to have accelerated battery ageing effects on other vehicles;

e.    By validation of the cells, battery packs and complete systems by more stringent and sophisticated performance test protocols under various load cycles and climate conditions, focusing specifically on the effect of fast charging on thermal and electrical behaviour.

Combining these innovations leads to an extended first lifetime of the battery cells, i.e. over 1,000 cycles and over 300,000 km and to the ability to reuse the battery pack by accurate prediction of the cross-over point for second use and for recycling. This life cycle mileage is a more than 80% improvement compared to the benchmark.

This objective will be achieved through a combination of the following activities and measures:

a.    By considering eco-design criteria, based on circular economy principles in the design and development of the battery pack (manufacturing and dismantling (including their automation), BMS (tailored for second life use), LCA (Life Cycle Analysis), reuse (second life) and recycling) and usage of environmentally friendly materials;

b.    By developing specific processes for the sustainable dismantling and recycling of battery systems and their components;

c.    By applying cross-training strategies on AI-based algorithms through combining and using input data from various vehicles, fleets and systems already transferred to second-life applications and their corresponding battery passport data leading to accurate crossover prediction from first to second use and to recycling, and therefore achieving valuable reuse and a high recyclability percentages;

d.    By carrying out a comprehensive LCA to guide the development process from an environmental point-of-view and validate the improved resource efficiency and environmental performance of the LIBERTY-battery system.

Combining all these actions and measures will lead to at least 20% LCA improvement compared to the existing benchmarks.