Laptop battery failure can be caused by a variety of factors, including overcharging, prolonged exposure to high temperatures, and age. Overcharging can cause the battery to overheat, which can reduce the battery's life. Prolonged exposure to high temperatures can also reduce the battery's life. Additionally, laptop batteries degrade over time, which can lead to decreased performance and eventual failure. To avoid battery failure, it is important to follow the manufacturer's instructions for charging and storage.