Is it safe to charge li-ion at max current all the way to full V?

Power Battery Products
1

This article states a li-ion cell should be charged at max current until it’s full.

  • Isn’t it safer to reduce current before the cell reaches full?
  • Won’t the charge current naturally reduce when the cell is nearly full?
  • How can you “gradually reduce current” if the cell is full? How can there be any current?

Thx

2

Hello,
Welcome to the DigiKey TechForum. Typically, PMICs charge LiPo and Lithium-Ion batteries using the CC-CV method. The battery gets charged with a constant current until the cell reaches its maximum voltage. From then on, the charger gradually decreases the charge current until the battery is fully charged. Modern charge ICs apply a few more steps to the process to increase safety. These ICs monitor the cell temperature and have a programmable cut-out function that stops charging the cell after a pre-set period.

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3

Hello @boom,

We need to be careful with our terms. For example, consider this battery by Spark Fun.

It has a maximum discharge current of 3.9 A, but a maximum charge current of 1.6 mA. This comes with several stipulations/cautions such charging at temperature extremes. There is also a cycle life that is specificized at significantly lower charge and discharge current when compared to maximums. The implication is that lower currents prolong battery life.

For more information please see:

Best Wishes,

APDahlen

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