# At what point in the charge cycle do lithium ion batteries draw the most current?

When charging lithium ion batteries do they draw a stable current throughout the charge cycle? Say you have used the battery until it shut down. When you put it on the charger will it draw more current at the beginning of the cycle or will it draw more as it gets close to a full charge? Or is it constant throughout the range?

And the same question regarding heat. Usually current and heat go together, but I don't know if a charging battery follows this pattern. Will the battery heat up quickly at the beginning of the cycle and stay at that temperature? Will it get hotter or cooler as it reaches full charge?

• You should forget the idea that the battery draws a certain current ! It is the charge controller which determines the current, not the battery ! If you make the voltage across a battery high enough, you can make the battery draw as much current as you like. Too much current (resulting from too much voltage) will damage the battery, some batteries might even explode. Apr 20, 2017 at 14:18
• @FakeMoustache In the field we like to use the term "rapidly disassemble". :) But yes, I agree Apr 20, 2017 at 21:00
• @FakeMoustache That makes sense. Any Li batt charger has to have circuitry to prevent overcharging. Beyond that, though, does a basic, no-frills charger do more than provide a steady voltage?
– Tom
Apr 20, 2017 at 22:10

The charging cycle of a li-ion battery looks like this:

As you can see, there are several phases:

1. precharging
2. constant current
3. constant voltage

The highest current is in constant current phase.

• Thanks. So charging voltage should never be higher than 4.1V/element whatever charging phase ?
– doom
Oct 1, 2019 at 10:52