A brief discussion on the misunderstandings of lithium battery discharge

"The more you discharge a lithium-ion battery, the more it wears out," said Tom Hartley, an electrical engineering professor at the University of Akron who helps NASA study ways to extend battery life. "The more you charge it, the more it wears out. Lithium-ion batteries are best kept in the middle of the pack, and that gives them the longest life."

First, too high or too low power levels have the most adverse effect on the life of lithium batteries, while the number of charge and discharge cycles is secondary. In fact, the number of rechargeable times marked on most electrical appliances or batteries sold is based on a test with 80% discharge. Experiments have shown that for some laptop lithium batteries, if the battery voltage is often allowed to exceed the standard voltage by 0.1 volt, that is, from 4.1 volts to 4.2 volts, the battery life will be halved. If it is increased by another 0.1 volt, the life will be reduced to one-third of the original; long-term low or no power levels will increase the resistance of the battery to the movement of electrons, thus reducing the battery capacity. NASA sets the battery power consumption on its Hubble Space Telescope at 10% of the total capacity to ensure that the battery can be repeatedly charged and discharged 100,000 times without having to be updated.

Secondly, temperature also has a great impact on the life of lithium batteries (this can be ignored for mobile phones and other small electronic devices). An environment below freezing may cause lithium batteries to burn out the moment the electronic product is turned on, while an overheated environment will reduce the battery capacity. Therefore, if the laptop is used with an external power supply for a long time without removing the battery, the battery will be exposed to the high heat discharged by the laptop for a long time. More importantly, if the battery is kept at 100% power for a long time, it will soon be scrapped.

From the above, we can summarize the following points to ensure the capacity and life of lithium batteries:

At present, most electronic products use lithium batteries. Since the advent of lithium-ion batteries in 1990, they have developed rapidly due to their excellent performance and have been widely used in society. As a result, lithium battery manufacturers have also achieved the largest scale of development. It is not necessary to charge lithium batteries to 100% full, let alone use up the power. If possible, try to keep the battery power close to half full, and the smaller the charging and discharging range, the better;

The factory design of General Motors' Chevy Volt electric car is to force the battery power to be maintained at 20% to 80%, and the built-in battery of Apple laptops may also use this method (including some other laptops and electronic products) to increase the number of battery charge and discharge cycles.

Do not use lithium batteries (especially laptop lithium batteries) for a long time when the device is powered by an external power supply. Even if your laptop has good heat dissipation, a long-term 100% charge is equivalent to killing the lithium battery.

1. If you use an external power supply to power your laptop for a long time, or the battery power has exceeded 80%, immediately remove the battery of your laptop. You do not need to fully charge the battery during normal charging, just charge it to about 80%; adjust the power options of the operating system, set the power alarm to more than 20%, and the minimum battery power should not be less than 20% during normal charging. Charge it before it drops to 20%;

2. For small electronic devices such as mobile phones, the power cord should be disconnected immediately after charging (including the USB port for charging). Leaving it connected will damage the battery. Charge it frequently and charge it when you remember, but you don’t have to fully charge the battery.

3. Whether it is a laptop or a mobile phone, never let the battery run out;

4. If you are going to travel, charge the battery fully, but please remember to charge the appliance whenever conditions permit. For the sake of battery life, do not wait until the battery is drained.