Ice Bucket Challenge! Will low temperature reduce battery capacity?

In the illustrated books used by many digital devices, we can see the operating temperature of the product, most of which are 10 degrees Celsius and 40 degrees Celsius. We know that the lithium battery is safe to work during charging and heating, and the low temperature electrolyte set in the high temperature and low temperature environment The internal efficiency of lithium batteries is low, which affects the use of users, and even causes low-temperature failure of the battery.

If you use a lot of mobile phones or batteries in the northern winter, you may find that when the temperature is low, the performance of the battery deteriorates, and even electronic products cannot be turned on. Let’s take a look at the performance of the battery at low temperatures.

The most important battery we use now is a lithium battery. In theory, the temperature effect of different lithium batteries is basically the same. In order to compare the impact of low temperature more intuitively, we chose a performance test that can quantify the power bank.

Portable power supply faces low temperature test

Considering the different batteries used in mobile power sources, we also set up two commonly used lithium battery mobile power sources for data sampling, including soft pack lithium batteries (commonly known).

The battery has a long service life at room temperature

In order to facilitate subsequent benchmarking comparisons, we first test the discharge performance of the mobile power supply at room temperature. As the data of the control group, the discharge environment temperature of the control group is 30℃.

Please note that we are here to compare the performance of the same battery at different temperatures. The power banks of the different batteries we tested have not yet been standardized. Therefore, these two types of cells are not comparable.

Discharge curve of soft-clad lithium battery at room temperature

It can be seen that the soft-pack lithium battery is stable at room temperature of 30°C, the overall voltage is about 4.95V, and the reference output energy is 35.1 watt-hours.

18650 battery room temperature discharge curve

The 18650 battery has little fluctuation at room temperature, the overall voltage is higher than 4.9V, and the stability is good. The reference output energy is 29.6 watt-hours.

mobile power at room temperature

It can be seen that both have excellent performance at room temperature, and stable discharge at room temperature can also provide excellent battery life guarantee. Of course, this is also the planning and application specification for mobile power and batteries. The next step is to test the battery’s discharge performance at low temperatures.

freezing point is a piece of cake

0℃ is the usual temperature of ice-water mixture, and it is also the temperature that must be observed before winter in northern my country. We first tested the discharge behavior of the mobile power supply at 0°C.

The water flow source is in the ice-water mixture

Although the temperature of 0℃ is a lower ambient temperature, it is still within the operating temperature range of the battery, and the battery should be able to work normally. We put the mobile power supply into the ice-water mixture, discharge after the temperature stabilizes, add ice to maintain the temperature, and finally export the discharge data.

The discharge curve of soft-clad lithium battery at room temperature and zero environment

It can be seen from the discharge curve that the discharge curve of the soft-pack lithium battery has changed significantly, all voltages and discharge time have been reduced, and the discharge energy has been reduced to 32.1 watt-hours.

18650 battery room temperature and zero environment discharge curve

The 18650 discharge curve is not significantly affected, but the initial voltage increases, but the capacity is significantly affected, down to 16.8 Wh.

It can be found that at 0°C, the battery is less affected and the voltage change range is not large, and it can be supplied to the user for normal use. In such an environment, the battery power supply should not be specially protected.

Emissions in cold environments are affected

minus 20 degrees Celsius is a very cold climate, and outdoor activities are severely reduced, but battery performance is also very important in this harsh environment. This is the low temperature we tested.

The discharge curve of soft-clad lithium battery at different temperatures

At -20°C, the discharge performance of the soft-clad lithium battery is obviously affected, and the discharge curve appears obviously jitter.