CIC energiGUNE, Europe´s leading research centre in the field of electrochemical and thermal energy storage, has taken a new step in developing more efficient batteries for use in space. The Monbasa project, led by the Basque centre in collaboration with Tecnalia and the companies Gencoa (United Kingdom) and Nanospace (Sweden), will make it possible to reduce the amount of material in the components of the batteries used in nanosatellites and, consequently, improve their energy density.
The recently completed project is based on the improvement of new processing techniques that allow the use of solid electrolytes integrated into a high voltage Li-ion battery. This will make it possible for these batteries to be compatible with the techniques that will be used to manufacture a new series of micro-sensors, which are already beginning to be integrated into the most advanced satellites.
Thanks to the introduction of these new techniques, the Monbasa project (Monolithic Batteries for Spaceship Applications) breaks with the reliability problems that Li-ion technology, based on the use of toxic and flammable liquid electrolytes, had generated until now. These drawbacks are attributed to the fact that liquid electrolytes, both below 0 degrees in charge and above 60 degrees in discharge, present safety problems. Also, because of the very low pressures in orbit, and in the absence of a pressurization system, the boiling point of the liquid electrolytes drops very low and becomes another safety problem. Also noteworthy is the fact that during launch, the batteries suffer vibrations and accelerations that can result in a leakage of liquid electrolyte.
The approach and use of the solid electrolytes integrated in a high voltage Li-ion battery is intended to demonstrate that with the processing techniques (magnetron sputtering, cathode spraying) it is possible to obtain solid Li-ion batteries with a higher energy density than the current ones based on liquid electrolytes. These batteries will improve the operation in the vacuum of outer space, as well as the temperature range, being able to operate in a greater interval and, in addition, thanks to their solid components without the presence of liquids, they will be equipped with a robustness capable of withstanding the vibrations and accelerations of the launch phase. The most immediate field of application for this type of battery will be that of nanosatellites, where the plan is to increase the number of launches from 25 in 2012 to almost 600 in 2020, with a view to other fields such as the Internet of Things (IoT) and Industry 4.0.
In general terms, Monbasa has pursued the achievement of a new battery suitable for its functionality in space that responds to five major needs: high energy efficiency and density, reduced size and weight, high reliability, compatibility with regulations and safety standards, and a high cost-efficiency index.
These processing techniques were very common until now, especially in the steel, glass and electronics industries, but had not been applied at an industrial level in battery processing, which is a challenge. In addition, taking advantage of the stability of the solid electrolytes, combinations of cathode and anode materials can be used in batteries with voltages much higher than those obtained in current Li-ion batteries, expecting to obtain 5 volts per cell instead of the current 3.7 - 3.9.
The Monbasa project, led by CIC energiGUNE researchers, is also a response to the need to position Europe at the forefront of the space race. The work carried out in the field of energy storage and its application in space is a fundamental part of European industry´s efforts to catch up with the leading countries in the space field: the USA, Japan and China.
