2016年10月27日星期四

The Cause of the Battery Explosion

Batteries that are much more energy-dense than lithium-ion batteries already exist, but are not safe enough to be portable, for example use in solar powered portable generator.

"The more energy you put in the box, the more dangerous it is," says Billy Wu, a lecturer at the Dyson College of Engineering and Design at Imperial College London. "Safety is key, and temperature management is critical. Temperatures in excess of 800 degrees Celsius lead to 'thermal runaway', and the components begin to decompose, leading to an explosion.

Samsung smart phone explosion of the specific reasons is still unknown, the company only revealed that the 'battery problem' lead.

The future of battery technology

In the short term, advances in batteries will rely mainly on lithium-ion technology will continue to push them to the theoretical limit, in order to improve the battery's energy density.

Lithium-ion batteries using lithium-manganese oxide generally have an energy density of 280 watts per kilogram, but the actual energy density of the final product is only 150 watts per kilogram, so there is still much room for improvement.

"The key is to optimize the internal structure of the battery," Billy Wu said, "the battery is a porous material filled with active material structure.

"To achieve greater energy output, it is necessary to increase the pore size of the structure to increase the surface area, allowing more lithium ions to pass through each time, but conversely, if the gap increases, the amount of active material can be reduced, resulting in reduced power.

Companies around the world are researching newer, more advanced battery chemistries such as lithium-sulfur or lithium-silicon cells.

In the more distant future, solid-state batteries may become a reality. In such cells, the liquid electrolyte is replaced by a solid material. This will greatly improve the safety of the battery.

"The main advantage of solid-state batteries is that they can continue to use lithium as an anode material," Wu explained. "Lithium has excellent energy density, but there are potential safety problems associated with the use of the electrolyte." For example, the lifepo4 batteries is stable.

According to Wu Jieshao, the use of zinc, lithium or aluminum as the main material of the metal - air battery is also high hopes, but the battery into commercial applications at least 20 years.


How to extend battery life

Some simple ways to help extend the battery life. Due to the chemical reaction characteristics in the battery, the battery is consumed more in the case where the residual electric power is less than 20%, or when the battery is charged in a state where the capacity is more than 80%.

Therefore, to maintain the lithium-ion battery power at 20% -80% level will help reduce battery loss, long time to maintain the battery's high power capacity. The same as lifepo4 battery pack when use it in solar power system. Intelligent power management systems under development are based on this principle.

Never let the phone remain in the long-term charge state, especially for laptops. Regular charging, discharge will help the battery to maintain a better working condition. Charge and discharge once a month can effectively extend the battery life.

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