Prevent lithium battery from heating and explosi-Lithium - Ion Battery Equipment

New technology to prevent lithium battery from heating and explosion in the United States -Lithium - Ion Battery Equipment

Car and mobile phone batteries often heat up and sometimes catch fire. In most cases, the culprit behind such incidents can be traced back to lithium batteries. Although the lithium battery can continuously supply current and keep the equipment powered, the lithium battery will often be short-circuited inside, causing the equipment to heat up.

According to foreign media reports, researchers at Texas A&M University in the United States have invented a technology that can prevent lithium battery from heating and failure. They designed carbon nanotubes for the conductive plate of the battery, that is, the anode, which can safely store a large number of lithium ions, thus reducing the risk of fire. In addition, the researchers also said that compared with the current battery on the market, the lithium battery with a new anode structure also charges faster.(Lithium - Ion Battery Equipment)

Juran Noh, a graduate student of the Department of Materials Science, said: "We have designed the next generation of anode for lithium batteries, which can continuously generate large current and also make the charging speed of equipment faster.". In addition, this new structure can prevent lithium from accumulating outside the anode, because the accumulated lithium will cause accidental contact between the two poles of the battery over time, which is also one of the important reasons for the battery explosion.

When a lithium battery is used, charged particles will move between the battery poles. The electrons released by lithium atoms move from one side of the battery to the other. When the battery is in the state of charge, the lithium ions and electrons will return to the original pole.

Therefore, the nature of the anode (the conductor containing lithium ion) plays a decisive role in the nature of the battery. A common anode material is graphite. In the graphite anode, lithium ion enters between the graphite layers. However, Noh said that this design limits the number of lithium ions that can be stored in the anode, and even more energy is needed to pull the ions out of the graphite when charging.

This kind of battery has a more dangerous problem. Sometimes, lithium ions will not be uniformly deposited on the anode. On the contrary, they will accumulate into blocks on the anode surface, forming a dendritic structure. As time goes on, dendrites will grow and eventually pierce the material separating the two poles of the battery, which will lead to short circuit of the battery and may also cause the equipment to catch fire. The growing dendrite will also affect the performance of the battery, because it will consume lithium ion and make lithium ion unable to generate current.

Noh said that another anode design would use pure lithium metal instead of graphite. Compared with graphite anode, the energy density per unit of metal lithium anode is much higher. However, because dendrites will also form, the battery will also fail in the same way.

In order to solve this problem, researchers have designed an anode made of carbon nanotubes, a highly conductive lightweight material. Such carbon nanotube supports contain spaces or holes that allow lithium ions to enter. However, such structures can not be combined with lithium ions smoothly.

Therefore, researchers have made two carbon nanotube anodes with slightly different surface chemical properties, one with a large number of molecular groups that can be combined with lithium ions, and the other with the same molecular groups but a small number. Researchers used this kind of anode to make the battery to test whether the battery has a tendency to form dendrites.

As expected, researchers found that the scaffold made of carbon nanotubes alone could not be well combined with lithium ion. Therefore, although dendrites are hardly formed, the ability of the battery to generate large current is also affected. On the other hand, the scaffold with too many molecular groups will form many dendrites, which will shorten the service life of the battery.

However, the carbon nanotube anode with the appropriate number of molecular groups can prevent the formation of dendrites. In addition, a large number of lithium ions can be combined and diffused along the surface of the support, thus enhancing the ability of the battery to continuously generate large current.

Researchers said that the current handling capacity of this anode is five times higher than that of commercial lithium batteries. Moreover, this ability is very useful for quickly charging large batteries, such as those used in electric vehicles.



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