Pocket electric fan highlights Huo Tong's second burn on his left hand.

It is very hot in summer. Many people will blow around with hand-held electric fans, but some children are burned. A parent said that the child's classmate brought a small electric fan to school, saying that charging stopped after a long time and asked him to help change the battery. As a result, when the back cover was opened, flames suddenly burst out, causing the child's left hand to burn twice, which made the parents feel quite distressed. At present, the industry has apologized.

▲ The hand-held electric fan caught fire and the boy's left hand was burned twice.

The doctor cut off the scalded dead skin with small scissors, and the small palm was tattooed by fire, which made my mother feel distressed.

The children cried and said, "It hurts ..." The doctor said, "This is a deep burn. 」

The children's thumbs, index fingers and middle fingers were blistered and even a little burnt. It's all the fault of this hand-held electric fan. After the accident, the handle and battery of the whole small electric fan were burnt black and deformed, which was really shocking.

▲ The handle of the fire fan was completely blackened.

Miss Chen, the parent of the scalded child, said: "My child told him that there must be something wrong with the battery. Let me take a look at it for you. Just change the battery. As a result, when he handed it over, he felt very hot, so he opened the back cover. As a result, after opening the back cover, he found a small flame. 」

The classmate charged the battery for a long time, but it still worked. The child kindly helped the classmate to change the battery but was accidentally burned, resulting in two burns on his left palm, but how could a good lithium battery catch fire?

▲ The cause of explosion may be related to voltage difference.

Physics teacher Zhang Pipai said: "Our charging circuits are all USB charging. USB changes 1 10 volts into DC 5 volts, so there will be a voltage drop of 1 volt between 5 volts and 3.7 and 4 volts. If it is charged for a long time, the battery temperature will be too high because 1 volt is working, and it will explode if it can't bear it. 」

The physics teacher explained that the key lies in the voltage difference between charging and lithium battery. Long charging time causes the battery to overheat, so it will burn or explode.

▲ In order to save costs, manufacturers do not install resistors, which may lead to abnormal overheating of the battery.

Zhang Pipai, a physics teacher, said: "In order to be greedy and cheap, commercial fans don't install this resistor because it requires labor and material costs. 」

Parents said that the manufacturer had apologized and promised to take full responsibility. Small electric fans are very rammed in summer, but we should be especially vigilant in use.