Can a Laptop Be Overcharged?

Laptop batteries are built to prevent overcharging.

The practical answer to whether a laptop can be overcharged is "no." While it is technically possible, this only happens in the case of a malfunction. Laptop batteries are constructed specifically to prevent them from overcharging.

Overcharging Lithium Ion Batteries

When charged beyond their normal operating voltage, the lithium ion batteries used in laptop computers become unstable. They can heat up and even catch fire.

Protection Circuits

Commercial lithium ion batteries are built with protection circuits that limit the charge voltage, keeping it one-tenth of a volt higher than the maximum voltage threshold for the charger itself so the charge never hits its upper limit.

Temperature and Pressure Sensing

A sensor will disconnect the charge in lithium ion batteries if the temperature approaches 90 degrees Celcius (194 degrees Fahrenheit). Many laptop batteries also have pressure sensors that will automatically disrupt the current if a safe pressure threshold is exceeded.

References

• Battery University: Charging Lithium Ion Batteries