Compared with the over 100 years history of lead acid batteries, lithium batteries have only been around for nearly 30 years. With the development of microelectronics in the last 20 or 30 years, the requirement of miniaturization of electronic devices has gradually defined the development trend of the battery industry – to increase the energy density of batteries while making them as small and portable as possible. Today, from mobile phones to laptops, from backup power supply to electric cars, lithium batteries are widely used in every aspect of our lives. According to statistics, more than 2 billion lithium batteries are produced every year, and more than 1 billion mobile phones and computers containing lithium batteries are being used in the world every day.
Highlights of Lithium Batteries
Higher energy density: Compared with lead acid batteries, lithium batteries are more durable for their higher energy density. The energy density of a lithium battery is about 200 wh/k, which is about 3-5 times that of a lead acid battery. Thanks to their higher energy density, lithium batteries also make it easier to be smaller and lighter.
Longer cycle life: Cycle life is the total charging and discharging times a battery can remain to be charged to 80% of its original capacity. The cycle life of a lead acid battery is about 300-500 times. A Li(NiCoMn)O2 battery can reach more than 1000 times, while a LiFeP04 battery can reach more than 2000 times. As a result, although a lithium battery is usually 2-3 times more expensive than a lead acid battery, its long-term cost of use is lower than a lead acid battery.
Compared with lead acid batteries, the advantages of lithium batteries also lie in their lower self-discharge rate, no memory effect and far less harmful to the environment after abandoned.
The Only Problem of Lithium Batteries
Lithium batteries are not without any drawbacks. Lithium batteries are slightly less safe than lead acid batteries. Although at a low possibility, lithium batteries are still at risk of exploding if they are not used properly. This problem rises from the quest for its high energy density. Here we will analyze this problem from the structure of lithium batteries.
Reasons of Lithium Battery Explosion
Structurally, a lithium battery consists of a positively charged cathode made of metal oxide, a negatively charged anode made of graphite, and liquid electrolyte containing lithium salts. The presence of liquid electrolyte allows electric charge to flow between the two poles. Generally, a permeable polyethylene separator is adopted between the two poles as a physical separation.
The demand to store more energy in the limited space of a lithium battery compels that separator to the limit, which can be as thin as 10 microns. In the process of charging and discharging the battery, if the separator is broken by an electric current, it will cause a battery short circuit, possibly followed by a fire or an explosion.
Solutions
To minimize the possibility of lithium battery accidents, both two aspects should be considered – the battery and the charger. When choosing batteries, remember to choose high-quality products from reliable brands. While choosing battery chargers, you should also choose high-quality products that matches your battery according to the parameters. In addition, if there is voltage fluctuation situation, ensure to keep the stability of voltage when charging your battery. Only by paying attention to these aspects at the same time can the long-term stability of lithium batteries be guaranteed.