The reluctance of OEM worldwide to extend electric drive applications to the private customers depends partly on considerations with respect to customer acceptance: limited range in the case of electric vehicles, long charging time after battery depletion, costs). But also on the increased reliability and life span that private customers are entitled to expect. The mission of the large scale integrating project HELIOS is to make CMOS photonics accessible to a broad circle of users.
The first goal of HELIOS project was to evaluate electrochemical couples (of lithium–ion cells) whose lower voltage window matches perfectly with the stability window of the electrolyte, which should guarantee an outstanding steadiness of the performance during ageing, and an intrinsic excellent safety.
The items that were evaluated are: performance, safety, life, recyclability and global cost. Another issue addressed by the project was the definition of a European standard for safety and life (cycle/storage) tests, adapted to high energy applications such as electric vehicles, plug-in hybrid electric vehicles and Heavy Duty Hybrid Trucks.
The project partners included six OEMs, one battery manufacturer, test Institutes/Universities and one recycler.
HELIOS drove the European RTD in CMOS photonics and paved the way for industrial development. The project included the development of essential building blocks such as: efficient sources (silicon-based and heterogeneous integration of III-V on silicon), fast modulators and, beyond, the combination and packaging of these building blocks for the demonstration of complex functions, addressing a variety of industrial needs:
- a 40Gb/s modulator on an electronic IC;
- a 16x10 Gb/s transceiver for WDM-PON applications;
- a photonic QAM-10Gb/s wireless transmission system;
- a mixed analog and digital transceiver module for multifunction antennas.
The results of HELIOS will pave the way for applications of CMOS photonics for other fields, e.g. sensors or optical processing. HELIOS will make integration technologies accessible for a broad circle of users.
It is important to find safer positive electrode materials and also to understand the reasons sustaining improved safety performance. Studies by Differential Scanning Calorimetry ('DSC') and Thermal Gravimetric Analysis ('TGA') indicated that oxygen release from charged cathode materials plays a significant role in the safety performance of lithium-ion batteries. Charged NCM has better thermal properties, in other words better safety characteristics, than that of conventional NCA, since NCM has limited oxygen release potential. Their onset temperature has been evaluated through ARC calorimetry studies. A difference of more than 100°C has been measured compared with the other layered materials like NCA. However, the total evolved heat is in the same order of magnitude as the other layered materials. Both Al3+ and Ni2+ substitutions for Co3+ seem to be the ideal strategy that leads to high energy density and good thermal stability altogether. However, note that NCA and NCM materials with low specific surface area are not readily available.
The project shows that the thermal behaviour of electrode materials are strongly depending on:
- the nature of the material;
- the nature of the electrolyte (salt, solvents, additives);
- the state of charge and state of health of the accumulator and;
- the origin of the increase of temperature which can be related to an operation at high discharge current. For example: to not well controlled environmental conditions, to an accidental overcharge (default of equalizing) or to an internal or external short-circuit.
Innovating for the future (technology and behaviour):
- A European Transport Research and Innovation Policy
- Promoting more sustainable development