Does playing while charging affect the battery of mobile phone?

I. Introduction

First of all, I copied a so-called popular science book that was widely copied on the forum. Part of the content is as follows:

So what's the harm of playing while charging? It depends on the battery. The regular battery has a protection circuit, and the output is very stable. It is designed according to the internal current limit of the mobile phone (I don't need to say fake). Therefore, it is relatively safe to play while charging the conventional battery, but when the battery is not full, playing while charging will generate a lot of heat. At this time, the current activity is very high, so the mobile phone, battery and charger are all running under heavy load. Working while charging when the battery is dead is fatal to the battery. In addition, playing like this without full charge will affect the protection circuit and battery of the mobile phone. According to analysis, the voltage of the mobile phone is higher when it is charged than when it is in standby. If you answer and make a phone call at the same time, the voltage will be many times higher than usual at the moment of talking or connecting to the network, which will easily damage the sensitive and complicated parts inside the mobile phone, resulting in frequent maintenance of the mobile phone. Secondly, the radiation during charging is dozens of times higher than usual, which will cause harm to human body. In addition, because the service life of the battery is calculated according to the charging and discharging cycle, the charging times directly affect the battery life. If the power supply is unplugged repeatedly, the life of the battery will be shortened due to repeated charging and discharging, so it is best not to answer the phone and send text messages when the mobile phone is charging in the turned-on state. n

Well, a brief summary of the above, we can draw the original author's three basic views:

+0. The battery will generate a lot of heat when charging.

2. When charging and talking, the instantaneous voltage will be many times higher than usual.

3. The radiation during charging is also dozens of times than usual.

Therefore, the author concludes that not playing mobile phone while charging will have many negative effects. I am writing this article today to expose the above misunderstanding and return the truth. At the same time, please pay attention to whether there are many times and dozens of times as mentioned above.

Second, the evidence

1. Does the battery really generate a lot of heat when charging? Here I open a portal, which is an early test I did: the research on the temperature rise of lithium-ion battery during charging and discharging. For your convenience, let's put some test data as follows: It can be seen that the lithium-ion battery hardly generates heat when charging, and even with a current as large as 1C, the temperature rise is only 1.5 degrees, which can be ignored. Lithium-ion batteries will only have a certain temperature rise when they are continuously discharged at a high current (1A), which is not enough to generate heat. However, to the extent of ordinary users' use, the temperature rise of lithium-ion batteries is only 2.4℃ even if they keep surfing the Internet (discharge current is 300mA) and keep making phone calls. There is still a certain distance from fever, which is almost negligible. 2. When charging a call, will the instantaneous voltage be many times higher than usual? For this reason, I designed three groups of states, and used an oscilloscope to capture the voltage on the battery: a. The voltage when the mobile phone is in standby; B. the voltage when the mobile phone is charged; C. A detailed description of the voltage when the mobile phone is charging and talking. As can be seen from the picture, there are not many such phenomena. What is the concept of many times? Even if it is 2 times, there is a voltage as high as 8V. The withstand voltage of most mobile phone chips is only 5.0V, which does not need many times. It only takes more than 1V to die, which shows that the original author is extremely lacking in common sense of mobile phones. 3. The radiation during charging is also dozens of times that of usual? It is necessary to briefly explain the generation of mobile phone radiation here. The mobile phone radiates radio frequency emission from the mobile phone, and its emission frequency falls between 850 MHz- 1900 MHz, which is in the microwave frequency band. GSM mobile phone can reach the peak power of 2W when transmitting, because of the microwave effect, it will radiate to nearby human tissues. In the industry, the specific absorption rate of SAR is used to measure the radiation of mobile phones. According to international standards (including China), the SAR value of GSM mobile phone is less than 2.0W/Kg (the average value is 10g human tissue). The test equipment and simulation calculation method are as follows: This figure shows the three-dimensional simulation result obtained by processing the data after the test, and the maximum value is taken as the test result. Well, with the test equipment and test standards, let's make a comparison. The design experiment is as follows: A: Test the SAR value of the mobile phone (900 MHz level 5 power, that is, the maximum power of the mobile phone) without inserting a charger. B: Plug in the charger and test the SAR value of the mobile phone (900 MHz power, that is, the maximum power of the mobile phone). C: Plug in the charger, and the mobile phone is in standby state (that is, the mobile phone is not talking), because the SAR test will give me a typical screenshot of only the maximum value and other data as follows: (It takes 1 complete days to complete the above test on a mobile phone. Due to the limited time, I temporarily quote a previous test report. I happened to have done SAR test with charger, because the conventional SAR test is without charger) A: 0.964 W/kg.