what will happen if mobile phone lithium battery overcharge

It's a common misconception when it comes to charging: it's best to stay fully charged. It may be fatal for Obsessive-compulsive disorder to jump from 100 percent to 99 percent, but it's not a recommended practice to keep your phone charged at all times, especially when the device is fully charged.

Lithium batteries are not everything

A lot of elders will tell you when you get the first mobile phone, the new mobile phone to complete all the discharge, then charge for 12 hours, and then complete discharge, need to repeat 3 times. At the beginning of the silly you must do according to the elders of honesty, but in fact has used lithium battery smart phone no longer need such trouble battery maintenance process.

Nickel-metal hydride battery needs to be discharged and charged for many times. This kind of battery has a strong memory, and the process of repeated charging and discharging is also to get the maximum charging limit of nickel-metal hydride battery. But today's mobile phones use lithium batteries, so there is no need to repeat such a complex battery memory process. So, will lithium batteries keep their maximum charge?

The answer must be no. Although lithium battery is known for its durability, it will inevitably lose its upper limit in the process of charging and discharging after many times of battery cycle. This loss is accumulated over time, and the reason for the loss is beyond normal charging, and overcharging is the culprit.

How to understand the phenomenon of overcharging

In fact, overcharging is very easy to understand, that is, the mobile phone is still charging the mobile phone battery under the condition that the battery is full, at this time we call the mobile phone is overcharging. When the battery is fully charged, continuous charging will lead to changes in the structure of the anode material, resulting in loss of capacity, and violent chemical reactions will occur between the liberated oxygen and the electrolyte. The worst result is naturally explosion.

In real life, there are many cases of mobile phones exploding while charging. For example, xinhuanet once reported that a 23-year-old girl was burnt while charging her mobile phone on March 4, 2015. Shanxi evening news also reported that an 18-year-old boy was electrocuted while charging his mobile phone on June 15, 2015. The reason of these tragedies can be attributed to the battery itself is damaged, the charger does not have IC protection, the power supply itself has quality problems and so on. When the current is continuously input after charging, because the battery capacity has reached the upper limit, most of the current is consumed by changing from electric energy to thermal energy, and the battery starts to get hot.

Common sense also tells us that the best way to store batteries at room temperature and dry, whether nickel hydrogen batteries or lithium batteries are actually the same. When overcharging occurs, there is no doubt that the heat energy transformed by the current will be released in large quantities, which will lead to the reaction of the lithium battery anode electrolyte and consume the maximum capacity of the lithium battery. When the heat accumulates to a certain extent, fire and explosion are possible.

Faced with such low security, it is natural that phone manufacturers and charger manufacturers will not sit idly by. After all, when the user has a security problem, it must be their bad luck, so there is a lot of attention when charging the mobile phone, especially now the mainstream mobile phone and charger with a USB port for charging are very particular about.

They're really hard to fight against overcharging

In fact, now most of the mobile phone has the existence of IC protection. The charger itself also monitors the voltage and current. In order to protect the safety of battery and users, trickle charging is often used in mobile devices.

If the loss on the wire is not calculated when charging with the USB port, the USB charging port will negotiate with the mobile phone to charge and match the appropriate current, so that the mobile phone will not lose most of the current due to the high current input. In low battery power, such as about 10%.

Charging the battery is most efficient and the current is at its highest. With the increase of electric capacity, the current mobile phone requirements will gradually decreases, and the arrival of the last remaining 10% ~ 20% even when full electric pulse small current to charge mobile phone will ask, so as to achieve the aim of protecting the battery, the charging ways, also known as trickle charging, is the mainstream mobile phone charging scheme, in order to reduce the wastage of the upper limit of capacitance, extend battery life.

In addition to providing overcharge protection for the phone's battery, another way is to rely on the charging socket to prevent overcharge. Socket to provide anti-overcharge must first provide a stable voltage, the greater the voltage fluctuations will be affected by the current. Especially in China, the time voltage fluctuates frequently at night, so it is very important to ensure the stability of the output voltage of USB port. Generally speaking, the voltage of the USB charging port is 5V. Some USB charging ports that can intelligently distribute current will slightly lower the voltage of the charging port when the phone battery is close to the full state, so as to reduce the input current and relieve the battery pressure.

These methods have a very good inhibitory effect on mobile phone overcharging, but in the final analysis, it is because we did not unplug the power supply when the mobile phone was charged, so that the mobile phone kept repeating the process of discharging and charging, resulting in the reduction of the upper limit of capacity.

Overcharging is not a trivial matter

For ordinary mobile phone users, overcharging is really not a trivial matter. The battery life of mobile phone directly affects the time you use this mobile phone. If you let the mobile phone charge recklessly, it is believed that the battery will die within a year.

If you can see a slight bump on the back of the battery, it's probably due to overcharging. To put it in a big way, overcharging even directly affects your safety. Those poor quality batteries of copycat machines can't be guaranteed to let off fireworks or something. If you want to avoid overcharging fundamentally, it seems that you should start from time control.

The page contains the contents of the machine translation.