  While the efficiency of renewable energy components like inverters and PV
panels is at an all-time high, there are still research gaps for batteries.
Lithium-ion batteries have a lot of potential, but there are still some
problems that need fixing, such as thermal management. Because of this, the
battery management system accomplishes its goal. In order for a battery
management system (BMS) to function properly, it must make accurate estimates
of all relevant parameters, including state of health, state of charge, and
temperature; however, for the purposes of this article, we will only discuss
SOC. The goal of this article is to estimate the SOC of a lithium-ion battery
at different temperatures. Comparing the Extended Kalam filter algorithm to
coulomb counting at various temperatures concludes this exhaustive
investigation. The graphene battery has the highest SOC when operated at the
optimal temperature, as determined by extensive analysis and correlation
between SOC and temperature is not linear
