Four major usage "misunderstandings" that endanger the life of lithium batteries

Mobile power supplies bring convenience to our lives, but some incorrect operations in daily use and storage of mobile power supplies will prematurely end the life of the lithium batteries inside. This article lists several incorrect operations that endanger the service life of lithium batteries, hoping to help everyone avoid the safety hazards brought by lithium batteries to the greatest extent possible, thereby extending the service life.

Mobile power has become an indispensable digital device in the daily life of most consumers. We can see it in the subway on the way to and from work, or on the flight, train or long-distance bus to the destination. While we enjoy the convenience brought by mobile power, its safety performance is also something that everyone needs to be familiar with. After all, the lithium battery inside it will end the life of the mobile power prematurely if people operate it incorrectly.

Figure 1: Lithium battery in mobile power bank

Since most of the mobile power supplies on the market are composed of three main parts: lithium batteries (including 18650 or polymer), circuit boards and shells, and in people's traditional impression, when talking about the safety of lithium batteries, they will naturally think of various "explosions". So today we will talk about how to operate the mobile power supply correctly in daily use to avoid various ways of death of the lithium battery inside the mobile power supply.

Since the lithium battery inside the power bank is proportional to its weight, and some power banks with a capacity of tens of thousands of mAh have a weight of more than 200g, coupled with the design of using a plastic shell, it is easy to break the shell of the product when it falls. Especially for those low-priced and low-quality power banks, the shell is made of very fragile recycled plastic.

Figure 2: Internal wiring without any fixed power bank

Figure 3: The solder joints of the mobile power cell must be very strong

If the internal insulation design of a mobile power bank is not in place and the cable soldering points between the battery cell and the circuit board are easy to loosen, it is easy for the soldering to become desolderable when it falls. If the battery cell protection circuit is designed on the main circuit board, the contact between the battery cell wires and other parts of the circuit board is likely to cause a direct short circuit.

Some mobile power banks with more solid workmanship usually fix each wire of the battery cell firmly by some fixing method. The appropriate wire length and good fixing treatment further enhance the internal insulation effect. However, for most consumers, it is difficult to know the internal structure and insulation effect of the mobile power bank. Therefore, when we use the mobile power bank in our daily life, the first thing to pay attention to is to avoid the mobile power bank from falling.

What is temperature difference death? It means that the working temperature is too high or too low, which causes the capacity of the lithium battery inside the mobile power bank to drop sharply. The working temperature of most lithium batteries is -20°C-60°C, and the optimal working temperature is 0°C-40°C. Lithium batteries using different positive electrode materials also have different working and optimal working temperatures.

Figure 4: Lithium polymer battery inside a power bank

Figure 5: Some product packaging will indicate the use temperature

Figure 6: iPad will disable charging in cold weather

At present, there are many electronic products on the market that are well designed to protect lithium batteries. For example, Apple's iPad will automatically prohibit charging operations when the internal sensor detects that the ambient temperature is too low to avoid damage to the battery due to charging in a low temperature environment.

Therefore, when we use the mobile power bank in our daily life, we should also try to avoid the environment temperature being too low or too high, so as to avoid the sudden decrease of capacity or permanent damage of the battery cell, and directly scrap it.

Figure 7: A cell with short wires and fixed

I believe that many people have heard about the explosive news about lithium batteries. With the widespread popularity of lithium batteries in recent years, more and more electronic products are using them to replace traditional batteries. When lithium batteries first appeared, due to technical reasons, their safety performance was very low, and fire and explosion were very common. However, after continuous technological improvements, lithium batteries now have higher safety performance. However, puncture or fire can still cause lithium batteries to smoke or explode.

So when we need to discard the mobile power bank, never throw it into a fire or discard it with household garbage. A certain degree of puncture, crushing and burning will cause hidden dangers of smoke or explosion, and cause serious harm to the environment. It is worth noting that using inferior chargers will also cause a certain probability of lithium battery explosion. Compared with the discharge process, lithium batteries are most dangerous when charging, which is why most mobile phone explosions occur when charging. So we should buy reliable or original mobile phone chargers for daily use.

Due to the chemical characteristics of lithium batteries, the voltage will slowly drop even if they are not used. This is what we often call the self-discharge of lithium batteries. In addition, the self-discharge of lithium batteries inside mobile power supplies is more obvious, because the batteries inside most mobile power supplies are directly soldered to the circuit board. Consumers cannot remove the batteries and store them separately when not in use, and the standby or sleep circuits on the circuit board are always in working state, which will exhaust the power over time.

Figure 8: Cell protection circuit

Figure 9: Circuit board with cell protection function

Although the cell protection circuit inside the power bank will automatically cut off the circuit to reduce the self-consumption of power when the cell power (voltage) drops to a certain value, the low voltage set for the protection circuit of the power banks on the market is different. Therefore, we should try to avoid leaving the power bank unused for a long time (three to six months or longer, depending on the self-consumption of the power bank) when the power bank indicates that the power is low. At this time, the cell will be over-discharged, and even directly cause the cell capacity to drop sharply. Therefore, after we buy a power bank, charging and discharging it at regular intervals is the best way to extend its life.

Summarize

In the end, many people's understanding of mobile power safety is almost all related to the internal lithium battery. Only correct daily operation can maximize the avoidance of safety hazards brought by lithium batteries, and enable it to have a longer service life and avoid premature scrapping. In addition, the continuous improvement of lithium battery technology has given it better safety performance. At the same time, some manufacturers have begun to use more reliable lithium iron phosphate batteries instead of traditional lithium cobalt oxide and lithium manganese oxide batteries to obtain higher safety performance.

In short, when we use and store mobile power in our daily life, as long as we avoid incorrect operations such as excessively high and low temperatures, falling, fire, and long-term unused storage, we can enjoy the various conveniences that mobile power brings to our daily lives. Of course, buying a mobile power with guaranteed quality and adequate after-sales service is also a necessary prerequisite.