Do you have any questions about why energy storage systems need a temperature control system and whether it’s possible to skip it? If you’re only looking for a straightforward answer, I’ll give you a definitive response: No, it’s not possible! For those who want to explore the reasons further, let’s dive in together.
First, I’d like to ask you a question. Now that winter has arrived, have you ever stayed in an environment where the temperature is below zero in the winter? Have you ever experienced your phone freezing and shutting down? Perhaps you’re curious why phones shut down in winter—is it because they have a temperature sensor that turns them off when it gets too cold?
The answer is no. As usual, the reason for shutdown is that excessively cold weather causes the phone’s battery voltage to drop and its discharge power to decrease. When the phone detects low voltage and power, it assumes the battery is depleted and automatically shuts down. Therefore, before shutdown, you’ll see the message: “Insufficient battery power, phone will shut down automatically.” You might ask, why is that?
First, I’d like to ask you a question. Now that winter has arrived, have you ever stayed in an environment where the temperature is below zero in the winter? Have you ever experienced your phone freezing and shutting down? Perhaps you’re curious why phones shut down in winter—is it because they have a temperature sensor that turns them off when it gets too cold?
The answer is no. As usual, the reason for shutdown is that excessively cold weather causes the phone’s battery voltage to drop and its discharge power to decrease. When the phone detects low voltage and power, it assumes the battery is depleted and automatically shuts down. Therefore, before shutdown, you’ll see the message: “Insufficient battery power, phone will shut down automatically.” You might ask, why is that?
Temperature too low
When the temperature is too low, the chemical and physical resistance inside the battery increases, making it difficult for lithium ions to move between the electrode materials and the electrolyte. Due to the increased internal resistance, the battery cannot discharge at high currents, causing the phone to shut down. Refer to a graph illustrating the relationship between battery temperature, voltage, and capacity.
From the graph, you can see that when the temperature drops to minus 20 ℃, the open circuit voltage is 3.9V, and the maximum discharge power of the battery is 3.2V at a voltage of 4Ah, which is 12.8Wh. At 25 ℃, the open circuit voltage is 4.12V, and the maximum discharge power of the battery is 3.3V at a voltage of 5.5Ah, which is 18.15Wh.
Freeze shutdown, how to turn on your phone
In winter, after your phone freezes and shuts down, how to turn it on? You can use the hottest part of your body to warm up your phone. Wait for three to four minutes until it warms up before turning it on. Remember not to expose your phone to excessively cold environments for too long after turning it on, otherwise it will shut down again.
What will happen if the battery temperature is too high?
Excessive temperature may cause phase transition and dissolution of the positive electrode material at high temperatures, resulting in the loss of its ability to store lithium ions. Electrolyte is unstable at high temperatures and can undergo oxidation, decomposition, and gas production, leading to battery swelling.
The higher the temperature, the more severe the side reactions, and even cause the battery cells to catch fire and explode. That is to say, excessive temperature can lead to a decrease in the lifespan of battery cells, and this is irreversible.
The higher the temperature, the more severe the side reactions, and even cause the battery cells to catch fire and explode. That is to say, excessive temperature can lead to a decrease in the lifespan of battery cells, and this is irreversible.
What is the best temperature？
You may not be able to go too low or too high, but what is the most suitable temperature?
Let’s take a look at the figure first. From the figure, it can be seen that when the temperature is at 25 ℃, the battery cell has the highest cycle life. That’s why some battery cell or energy storage manufacturers label the energy storage or battery life as “@ 25 ℃”, because this is the temperature required for the maximum number of energy storage cycles.
Why do we need a temperature control system?
Now let’s summarize why a temperature control system is necessary. When the battery cells are working, they are greatly affected by temperature. When the temperature is too low, the power output capacity is insufficient and may cause some side reactions. When the temperature is too high, it can cause many irreversible side reactions, even explosions, and reduce the service life. A good temperature control system is the guarantee for the long-term operation of energy storage systems.