The Vikram Sarabhai Space Centre (VSSC) under the Indian Space Research Organisation (ISRO) has achieved a significant milestone by qualifying 10 Ah Silicon–Graphite (Si-Gr) anode-based high energy density Lithium-ion (Li-ion) cells. These cells emerge as a promising, low-weight, and cost-effective alternative to the currently employed cells. The successful flight demonstration of these cells took place on the POEM-3 platform of PSLV-C58, where they powered a resistive load.
The Si-Gr anode-based cells demonstrated exceptional performance, with on-orbit voltage, current, and temperature values matching well with predictions. Unlike conventional Li-ion cells using pure graphite as anode material, the Si-Gr composite anode material allows for a higher accommodation of Lithium ions per unit mass, thereby enhancing the energy density of the cells.
Apart from the material innovation, these cells feature cost-effective hardware readily available in the market, and a crimped sealing-based design, effectively reducing hardware and fabrication costs. The Silicon High Energy Li-ion cells boast an energy density of 190 Wh/kg with an operating voltage ranging from 4.2 to 2.8 V, surpassing conventional Lithium-ion cells with 157 Wh/kg.
During the flight demonstration, the battery system exhibited an impressive performance, working for 21 hours in 15 orbits, delivering a capacity of 8.9 Ah, with a final drained voltage of 0.4 V. Prior to deployment in operational vehicles and missions, VSSC ensures rigorous qualification and flight demonstration of new systems, adhering to their piggyback payload approach.
The cells demonstrated their resilience and performance in the harsh space environment through the POEM experiment. Buoyed by this successful performance, the Si-Gr anode-based cells are now positioned to be employed in upcoming operational missions, offering an anticipated 35-40% battery mass saving. The versatility of the system extends to both space and ground applications, marking a remarkable advancement in high-energy-density Li-ion cell technology.