The advent of fast charging technology has revolutionized the way we recharge our devices, including LiPo batteries. LiPo (Lithium Polymer) batteries are commonly used in various applications such as drones, RC cars, and portable electronics. However, many users wonder whether fast charging has any impact on the performance and lifespan of LiPo batteries. In this article, we will explore the effects of fast charging on LiPo batteries and provide insights into how to maximize their longevity.
What is Cycle Life of Lipo battery?
As we all know, one of the advantages of lithium-ion batteries is that they can be charged at any convenient time without having to completely discharge the battery. So, what is a charging cycle?
One charging cycle means that the battery’s entire charge is depleted from full to empty, and then recharged from empty to full, which is not the same as charging once. To put it simply, for a 600mAh lithium battery, you first charge it from 0mAh to 400mAh, use it for a while, then charge it again with 150mAh, use it again, and finally charge it with 100mAh. When the battery is charged to 50mAh for the last time, one charging cycle of the battery is completed. (400 + 150 + 50 = 600)
A lithium battery was only half used on the first day and then fully charged. If the same thing happens on the second day, that is, using half and then charging, it only counts as one charge cycle, not two. Therefore, it may take several charge cycles to complete one cycle. Each time a charge cycle is completed, the battery level will decrease slightly. This is why many people who use lithium battery phones often say, “This damn phone, when I first bought it, I could use it for 4 days, now I can only use it for 3 and a half days with one charge.” However, the amount of decrease is very small. After multiple charge cycles, high-quality batteries will still retain 80% of the original charge, and many lithium battery-powered products can still be used normally after two or three years. Of course, lithium batteries still need to be replaced when their lifespan is over.
The lifespan of a lithium battery is generally 300-500 charging cycles. Assuming that a full discharge provides 1Q of electricity and without considering the reduction in electricity after each charging cycle, the lithium battery can provide or replenish a total of 300Q-500Q of electricity within its lifespan. Therefore, we know that if we charge it every time it is used to 1/2 its capacity, it can be charged 600-1000 times; if we charge it every time it is used to 1/3 its capacity, it can be charged 900-1500 times. In any case, the total amount of electricity replenished is constant at 300Q-500Q, regardless of how it is charged. Therefore, we can also understand that the lifespan of a lithium battery is related to the total amount of electricity charged, not the number of charging cycles. The impact of deep discharge and deep charging or shallow discharge and shallow charging on the lithium battery lifespan is not significant.
In fact, shallow charging and discharging is more beneficial for lithium batteries. Only when calibrating the power module for lithium batteries in the product, deep charging and discharging is necessary. Therefore, products powered by lithium batteries do not need to be restricted by the process. Convenience should be the priority, and they can be charged at any time without worrying about affecting their lifespan.
So lithium batteries also have a lifespan issue during normal charging. Each charge also causes a slight damage to the battery, but this damage is minimal and may take up to a year or more to manifest on the phone. Therefore, both fast charging and normal charging actually cause irreversible damage to the battery, but the damage from fast charging is slightly stronger than that from normal charging. However, with the various safeguards of current fast charging technology, this battery damage is still in a safe and reasonable state.
Will Fast Charging Affect Lifespan of Lipo Battery?
Firstly, we need to understand the charging and discharging principles of lithium-ion batteries. The battery has two poles: the positive pole is a lithium compound, and the negative pole is graphite. Charging and discharging both involve the mutual conversion of electrical energy and chemical energy. During the movement of lithium ions between the positive and negative poles, they also transform into different compounds.
Fast charging is a relatively general concept, which has three different implementation forms:
(1) Keep the voltage stable and increase the current;
(2) Keep the current stable and increase the voltage;
(3) Increase both voltage and current.
We can think of lithium-ion as a charged small car: when charging, the electric field forces the small car to move to the negative pole to store energy (lithium ions are embedded in the graphite carbon layer of the negative electrode’s micropores); when discharging, these charged lithium-ion cars react chemically and move to the positive pole (lithium ions are deintercalated from the negative electrode, causing the positive electrode to be rich in lithium). This process generates an electric current for power.
In an ideal state, as long as the chemical structure of the positive and negative electrode materials does not change significantly, the reversibility of the battery’s charging and discharging is good, and the lithium-ion battery can ensure long-term cycling. Fast charging mainly ensures that lithium ions quickly intercalate and deintercalate between the positive and negative electrodes, and does not cause lithium ion deposition.
However, when the current increases, a semi-permeable membrane (SEI film) on the surface of the negative electrode (graphite) will crack to a certain extent, causing the electrode material and electrolyte to react with each other. In addition, an increase in temperature will also cause secondary reactions in the battery and damage the chemical substances on the battery, leading to a decrease in reversibility (i.e., the lithium-ion car cannot move back and forth), and the battery capacity will continue to decrease.
This is why we often feel that the battery is fully charged, but why it becomes less and less durable over time.
Currently, most companies that offer fast charging solutions have not provided information on the impact on battery life from the perspective of the battery. However, according to national standards, a battery capacity of 80% or more after 500 charges and discharges is qualified, and its effect on usage within a year is not significant.
Harm of Fast Charging: The rapid charging of lithium batteries comes at the cost of sacrificing the battery’s cycle life because the battery is a device that generates electrical energy through electrochemical reactions. Charging is a reverse chemical reaction, and fast charging will instantly input a large current into the battery. Frequent use of fast charging mode will reduce the battery’s reduction ability and the number of charging and discharging cycles.
Simply put, fast charging has high requirements for the quality of the battery, and the reaction conditions of the battery under high current are too harsh and violent, deviating far from the equilibrium state, which causes significant loss to the battery’s life and reduces the safety factor. Therefore, it is not necessary to use fast charging unless necessary.
While fast charging offers convenience and shorter recharge times for LiPo batteries, it is crucial to strike a balance between speed and battery health. Rapid charging can generate additional heat and stress, which may affect the overall performance and lifespan of LiPo batteries. It is advisable to follow the manufacturer’s guidelines and recommendations for charging rates and ensure you use a charger specifically designed for LiPo batteries.
To maximize the lifespan of your LiPo batteries, consider implementing the following practices: using a charger with a balance charging feature, avoiding overcharging or over-discharging, monitoring battery temperature during charging, and allowing sufficient rest periods between charging cycles. Additionally, proper storage and transportation measures should be observed to prevent any potential damage to the battery.
Remember that the lifespan of a LiPo battery is influenced by various factors, including usage patterns, charging practices, temperature exposure, and maintenance. By adopting a responsible charging routine and taking proactive measures to care for your LiPo batteries, you can optimize their performance and extend their longevity, ensuring reliable power for your devices or applications.