ISRO's Low-Cost, High Energy Density Lithium-Ion Cells Pass Flight Demonstration, To Be Used In Future Missions

The Indian Space Research Organisation (ISRO) on Friday (5 January) said that it has tested a novel type of battery cell that surpasses the efficiency of traditional ones used in its missions, and is also less expensive.

The national space agency said that it has qualified 10 Ah Silicon–Graphite anode based high energy density Li-ion cells as a low weight and low cost alternative to cells being used currently.

"The flight demonstration of the cells as a battery was successfully completed by powering a resistive load on-board the POEM-3 platform of PSLV-C58. The on-orbit voltage, current and temperature values of the battery were acquired through telemetry and found to match well with the predictions," the agency said in a statement.

"Based on the confidence gained through this performance, these cells are poised to be used in upcoming operational missions where 35-40 per cent battery mass saving is expected. The system find application both in space and ground use," ISRO added.

In contrast to traditional Li-ion cells that utilize pure graphite for the anode material, this cell employs a Si-Graphite composite as the anode material.

"This helps in accommodating more Lithium ions for a given unit mass of anode material and thus improves the energy density of the cell. In addition to the material change, this cell also employs cost effective hardware which are readily available and a crimped sealing based design which reduces the hardware cost and fabrication cost significantly," the ISRO said.

The energy density of the Silicon High energy Li-ion cells is 190 Wh/kg with an operating voltage of 4.2 to 2.8 V, against Lithium-ion cells (157 Wh/kg).

According to ISRO, during flight, the battery system worked for 21 hours in 15 orbits delivering a capacity of 8.9 Ah with final drained voltage of 0.4 V.

ISRO said that before inducting any new systems in operational vehicles and missions, it subjects the system to rigorous qualification and flight demonstration as piggy back payloads.

"Same approach is followed for these cells also. The capability of the cells to survive and perform in harsh space environment was also successfully demonstrated through the POEM experiment," it said.