The cold winter is coming; how many times do we feel the performance of batteries in our products containing batteries decline? Why is that? Now we have all kinds of electronic products around us, and in the winter, how can we make better use of them? Improve efficiency, let's reveal it!
Usually, the batteries that appear around us generate electricity through chemical reactions, and at low temperatures, the speed of the reaction decreases significantly, affecting its charge and discharge speed. The chemical reaction is generally accelerated in the case of mild adaptation, so the charging and discharging capacity of our electric vehicles and mobile charging stations is reduced.
In particular, it is at low temperatures that the rate of lithium ion migration from the plus electrode to the minus electrode decreases substantially, and the internal resistance of the battery increases, which is manifested by a voltage drop during discharge and a loss of efficiency during charging.
We can imagine that there is electrolyte inside the chemical battery, which is the medium of ion conduction. Under low-temperature conditions, the viscosity increases and reduces the migration of ions. This phenomenon is especially serious for lithium-ion batteries, due to the fact that the migration of lithium ions relies on the flow of electrolyte. When it comes to low temperatures, the ability of ion diffusion decreases, which influences the normal operation of the battery.
Low-temperature charging means that the electrochemical reaction rate of the lithium battery cannot keep pace with the input speed of the current. Therefore, lithium metal may be deposited on the negative surface of the battery to form lithium dendrites. It will not only reduce the battery capacity but also may puncture the battery diaphragm to cause a short circuit and even cause safety accidents of the battery.
The self-discharge rate of some batteries at low temperatures may increase, and the battery power will be reduced. Aging batteries are especially sensitive to this. In winter, a fully charged device will also lose power quickly in standby state.
The low-temperature environment may cause changes in the performance of the battery material. For instance, the positive and negative electrode materials of the battery may cause stress due to different coefficients of thermal expansion. Also, the mechanical structure is less stable at low temperatures, which will indirectly affect the performance of the battery.
In winter, the battery range of electric vehicles drops significantly, mainly because low temperatures make lithium ion diffusion difficult. Besides, the thermal management system and heating equipment in an electric vehicle increase power consumption at low temperatures.
In winter, we often encounter mobile phones automatically shutting down or reacting slowly in low temperatures; this is because the battery output voltage cannot maintain normal power supply. 3. The energy storage device's efficiency goes down. Home energy storage or industrial energy storage systems will show a decline in efficiency in winter and affect the stability of overall energy management.
Third, the strategy to deal with the declining performance of battery in winter
In the face of winter's impact on battery performance, we can take the following measures:
Try to maintain the battery within the appropriate operating temperature range (usually 10℃-25℃). Mobile phones for daily use can be stored in a warm place indoors; Electric vehicle battery, battery insulation device can be used during parking to reduce low temperature exposure time.
Low-temperature charging is an important cause of lithium deposition. You are advised to charge the battery after the battery temperature rises to a reasonable range. For example, when using electric vehicles in winter, heating equipment can be used to preheat the battery; Household battery devices can also be set at a constant temperature to ensure the safety of the charging process.
There are already batteries that are optimally designed for low-temperature environments on the market. Examples are the low-temperature electrolyte formulations used in some electric vehicles, which can maintain good performance at -20 ° C or even lower. Besides, some batteries are also fitted with a self-heating function, which can heat the battery to the right temperature before use.
When using the battery in winter, try to avoid completely running out of power, and the battery in the state of low power is more vulnerable to low temperature damage. In addition, minimize high-power discharge behaviors, such as rapid acceleration or heavy load operation.
The moderate preheating of the battery prior to use can improve the battery performance. For instance, a cellular phone can be warmed up by putting it in a pocket for some time; electric vehicles can raise the temperature of the battery by slightly preheating the device before starting it.
As an indispensable storage device in modern life, the performance of batteries directly affects the convenience of our lives. Low temperature in winter affects battery performance, and scientific management and technical optimization can reduce the impact as much as possible. In the future, with the continuous development of new materials and new technologies, the low-temperature performance of batteries may also be improved.
Therefore, the effect of low temperatures on batteries will be recognized, and an appropriate use strategy will be adopted in such a way that it will not only prolong service life but also effectively improve its safety and reliability. Not only the users of individual devices, but also industrial energy storage users, should pay more attention to the management of batteries in low temperatures and adapt better to cold challenges.
