Lithium battery history for 40 years: why the balance cars still explode?

40 years of history, lithium batteries will explode

On September 2, Beijing time, the Yonhap News Agency quoted Samsung Electronics official as saying that due to the risk of fire in the battery, Samsung is expected to announce the global recall of the Galaxy Note7 smartphone. Unfortunately, any battery-equipped product has the potential to explode. The recent Note7 explosion is not new, and even the brand that has not exploded has been a minority. Even Apple’s iPhone has exploded event.

The explosion of the mobile phone battery made the author have to think of a series of events that balanced the car explosion in early 2016. At the beginning of 2016, the continuous occurrence of self-ignition and passenger crash of the balance car prompted the US Consumer Safety Commission to issue an open letter stating that “all electric balance cars in the US are not safe”, Amazon, Toys R Us and Target, etc. The retailer has removed the electric balance car. At the end of 2015, the United Kingdom and Australia issued a ban to prohibit smart balance cars on the road.

Whether it is a mobile phone or a balance car has exploded, why is the culprit every time a battery? "The MIT Science and Technology Review recently published an article saying that we have not used more energy storage devices than the 40-year-old lithium-ion battery, which means that lithium batteries are the best batteries at the moment. However, technology has become so advanced, and lithium batteries have exploded from time to time, making it difficult for ordinary people to understand.

However, everyone should not worry too much, because of the trend of lithium ions, lithium-ion batteries have higher energy density, power density, better cycle performance and reliable safety performance.

The battery is not the culprit, the high temperature is terrible

To understand why lithium batteries are always the cause, you must first know the structure of the lithium battery. The two ends of the lithium battery are divided into positive and negative poles, the electrolyte is installed in the middle, and the voltage flows through the electrolyte to carry lithium ions from one end to the other end. This is the process of charging and discharging.

Now that battery technology is so advanced, why the balance car will also explode the structure of the lithium battery?

Usually this process will not have any problems, but when the problem occurs, it will have great consequences at a very fast rate. As for what will happen? One of the common problems is overcharging, which causes the battery to overheat, and even further chemical changes in the positive electrode, which may eventually ignite or explode. Don't think that battery overheating will only happen to overcharge. Similarly, overdischarge will also cause the same accident, because the anode contains oxides, which will react with the electrolyte and release heat. Inferior batteries may also cause the above reaction due to impurities entering the electrolyte.

A dangerous battery that cannot withstand the danger of overheating in an explosion

Don't underestimate the problem of battery overheating, because overheating will cause the reaction to accelerate. Once the temperature continues to soar to 150 °C or even exceed, it is likely to burn in your pocket or bag.

Now that battery technology is so advanced, why the balance car will explode inferior lithium battery is prone to overheating.

As for when the lithium battery may overheat? This is hard to say. Some inferior or problematic, or in the case of improper use, the lithium battery is likely to be overheated on the first charge or discharge; and some may weaken as the number of charge and discharge cycles increases, resulting in overheating. Whether it is the positive and negative electrodes or the electrolyte, as long as there is a problem, it may cause a big disaster, which may be the reason for the explosion of the Segway balance car.

It is reasonable to say that any balance car or mobile phone manufacturer will have this measure to prevent the battery from overheating and causing fire or even explosion. Of course, the originator Segway balance car is no exception, and more and more balance car explosions occur frequently. What is wrong with it problem?

Why is the Chinese smart balance car being hit by the American big stick to go back to the safety protection mechanism and eventually cause an explosion?

The battery itself usually has a chip that protects the circuit from overcharging or overdischarging. However, many manufacturers will invisibly add a layer of protection to the outside of the battery for the stability of the battery. This layer of protection is like quilting the battery. The heat generated by the battery cannot be transferred and dissipated. This design is not the main reason, but it will have a certain impact.

Now that battery technology is so advanced, why the balance car will also explode the circuit that protects the circuit?

The most important thing is that the chip that protects the circuit does not seem to work, otherwise there will not be so many explosions.

There are already many people thinking about it, so why not invent a battery that won't overheat? Of course, it can be a little difficult for the battery to not overheat, but at least the scientists have moved in this direction. Researchers at Stanford University designed a mechanism in which they invented a membrane that would expand if the battery overheated until the negative electrode was covered to block the current.

When we continue to emphasize how big the battery capacity is, and emphasize how strong the balance car's battery life is, does it also ignore the safety of the battery? This may be a problem that all balance car manufacturers should think about.

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