Getting the Most From Li-ion Batteries


Lithium-ion batteries are everywhere these days, used in everything from cellphones and laptops to cordless power tools and electric vehicles. Although they are the most widely used batteries for mobile devices, there are lots of myths and confusion on how to prolong (or at least not shorten) their life.

To clarify the situation researchers at University of Michigan researchers dug through a pile of academic papers and user manuals, as well as websites on customer support. They came up with a list of nine best practices for lithium-ion batteries. Here are the nine tips,  along with a few recommendations from manufacturers:

1. Avoid high temperatures when storing or using them.

2. Avoid low temperatures, especially when charging.

High temperatures make almost every battery component degrade faster. They also increase the risks of fire and explosion. And if a laptop or cellphone is noticeably hot while it’s charging, unplug it.

For electric vehicles, nearly all manufacturers warn of high temperatures in their owner manuals. Some of them advise parking in the shade and keeping the vehicle plugged in during hot weather. This lets the battery cooling run as needed. Plugging in the vehicle is also recommended in cold weather to let the battery heater can run on grid power.

3. Minimize the time the battery spends with a 100% charge.

4. Minimize the time the battery spends with a 0% charge.

Both extremely high and low “states of charge” stress batteries. Consider using a partial charge that restores the battery to 80% of charge instead of 100%. If that’s not possible, unplug the device as soon as it reaches 100%.

Samsung and LG suggest that their phones should be recharged when they reach a 20% state of charge. Nokia and Sony mention potential damage to their phones if the device is left charging after reaching 100%.

In most laptops, internal battery management system stops charging once the device reaches a 100% charge, and it will not resume charging until the laptop reaches a 95% charge. Even so, many laptop manufacturers caution against leaving computer plugged in after charging is complete.

5. Using “fast chargers” degrades the batteries more quickly than standard charging.

6. Discharging batteries too quickly also degrades batteries.

For cellphones and laptops, lowering screen brightness, turning off location services and quitting high-power-use applications slows the discharge rate. Some manufacturers of cordless power tools tell users not to store batteries in the charger, while others caution against running down the battery completely. A few recommend a minimum ambient temperature of 32°F when charging the battery, and a maximum of 104°F.

7. Avoid use or storage of lithium-ion batteries in overly moist environments.

8. Avoid mechanical damage such as puncturing.

9. Follow the manufacturer’s calibration instructions.

In general, there are two forms of battery degradation: capacity fade and power fade. Capacity fade is a decrease in the energy a battery can store; power fade is a decrease in the power it provides.



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