# Current in a Lithium Ion Battery

I am trying to find the current transferred to the anode and cathode of a Lithium Ion Battery at different voltages. I know the temperature (approximately) of the battery, the battery's starting voltage, the voltage at 30sec intervals of a constant power discharge (from which current can be deduced), the dimensions of the battery and the initial amount of charge in the battery. What could I do to find this current transfer?

• Use ammeter instead? – Mithoron Sep 14 '18 at 20:55
• Do you mean "current" (e.g. mA) or "charge transfer" (e.g. mAH)? – DrMoishe Pippik Sep 14 '18 at 21:53
• Current so it would be mA and can't really use an ammeter because that would require me opening up the battery which is kind of hard at this stage. – user446153 Sep 14 '18 at 22:22

Power is the energy transferred per unit time ($\frac{J}{s}$) and is determined by the potential drop (V) and the current (I) at a given point in time as $P = IV$ so to get the current, solve for $I=\frac{P}{V}$. This gives you the current at a given point in time.
Your question has a few points that might be worth addressing. As Dr Moishe Pippik commented, "current transferred" is a little confusing, either instantaneous current ($I$), or total charge transferred ($Q$), which is the current integrated over time: $\sum_{t} I(t)\Delta t$ in your case. So if what you really want is the total charge transferred, you would have $Q = \sum_{t}\frac{P\Delta t}{V(t)}$. Strictly speaking you should exclude t=0 point to avoid double counting.