High specific energy next generation of Lithium based cell over 250 Wh/kg
- Paper number
IAC-08.C3.2.8
- Author
Mr. Nicolas Paquin, SAFT, France
- Coauthor
Mr. Yannick Borthomieu, SAFT, France
- Year
2008
- Abstract
The current Li-ion technology reaches 180 Wh/kg. The last Li-Ion cell developments for Space use delivers up to 170 Wh/kg. Saft is just finishing the VE1S180 qualification which reaches this specific energy but is already working on the next generation of cell. The next cell generation is under research work at active material level. Among the large amount of candidates from positive and negative material point of view, it is not so obvious to select the best configuration in order to reach 250 Wh/kg. In fact, this value is the target for the Space cell specific energy as the step compared to the previous one is large enough to get a real advantage. The research team is working on different types of positive material as shown in the figure 1. From the standard Lithium metal oxides to the Spinel compounds, the Vanadium oxides and the Vanadium or Iron Phosphate, extensive work and studies have been done to evaluate these materials as active positive materials. There are still big issues with these materials: ability for cycling, calendar and fading losses and thermal stability. Even if all of these materials are promising from power point of view (mainly the Iron phosphates), there is no material that gives a significant specific capacity increase. To get a specific energy increase, the use of “high voltage 5 V” materials is a true possibility. The main key point of the use of high voltages is the electrode stability. Increasing the charge voltage needs to slow down the oxidation reactions with the electrolyte. So, the future research work needs to be focus on will be the stability of the selected positive material and the electrolyte versus the oxidation at high voltage. The candidates for the negative materials are more numerous than for the positive ones. In opposite to the positive materials, the “new” negative materials exhibit all an improvement of the specific capacity compared to the existing graphite or carbon materials. For the new cell design, the target is to get from 600 to 800 Ah/kg for the negative material. Among the candidates, the Silicium alloys with Tin and Carbon seems the more promising. The key point is the mechanical stability as these materials exhibit large volume change with the Lithium intercalation. The focus of this paper is to present the research challenges on new materials and electrolyte in order to be able to fly a 250 Wh/kg space cell within the next 10 years.
- Abstract document
- Manuscript document
IAC-08.C3.2.8.pdf (🔒 authorized access only).
To get the manuscript, please contact IAF Secretariat.