"Self-discharge" refers to the gradual loss of energy or capacity that occurs in a lithium-ion battery over time, even when the battery is not in use. This is due to a number of factors, including the natural breakdown of the battery's internal components and the leakage of small amounts of energy from the battery's electrodes.
The self-discharge rate of a LiPo (Lithium Polymer) battery can vary depending on several factors such as its age, temperature, and storage conditions. However, as a general rule, LiPo batteries have a self-discharge rate of approximately 5% per month when stored at room temperature (around 20-25 degrees Celsius) and in a partially charged state.
It's worth noting that storing a LiPo battery in a fully charged or fully discharged state can accelerate the self-discharge rate and reduce the battery's overall lifespan. Therefore, it's recommended to store LiPo batteries at around 50% charge, especially if they are not going to be used for an extended period.
Additionally, extreme temperatures can also impact the self-discharge rate of LiPo batteries. High temperatures can increase the rate of self-discharge, while low temperatures can slow it down. Storing LiPo batteries in a cool, dry place can help to extend their overall lifespan and reduce the self-discharge rate.
What measures can lithium battery manufacturers take during the production process to avoid delivering batteries with high self-discharge to customers? Let's take a look at how Ufine detects battery self-discharge rate.
To improve the self-discharge rate of lithium batteries during production, Ufine Has taken following measures:
Control production environment: Controlling temperature and humidity is key to reducing battery self-discharge during production. Maintaining a constant temperature and humidity can prevent changes in chemical reactions in the battery, thereby reducing self-discharge.
Use high-quality raw materials: Using high-quality positive and negative electrodes, separators, and other raw materials can reduce impurities and defects inside the battery, thereby reducing self-discharge.
Strict quality control: During production, strict quality control can ensure that the battery's performance and quality meet standards. Charging, discharging, temperature, and other tests can eliminate batteries with high self-discharge rates, thereby improving product consistency and reliability.
Charging treatment: Charging the battery during production can reduce its self-discharge rate. Charging can restore the chemical reactions in the battery to the optimal state, thereby reducing self-discharge.
At last,UFine could measure their discharge rate to determine their self-discharge rate.UFinebatter use an automated testing system (ATS) to test the battery's self-discharge rate. The ATS is an automated testing device that can quickly test large quantities of batteries and can automate testing and data recording as needed. This method can improve testing efficiency and accuracy as it eliminates human error and testing time constraint.
The following video demonstrates the method UFine uses to test the self-discharge rate of batteries.