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Can You Overcharge Rechargeable Batteries-Results, Frequency, and Protection
Rechargeable batteries are useful but suffer from a problem or two. You must have heard that you shouldn’t overcharge your electronic devices. But did you ever tried to find out the reason behind this?
Well, here we are to discover the fact that backs up the rule that overcharging is bad. Currently, it is the lithium-ion batteries that are being used in smartphones, laptops, tablets, power banks, and other self-operating and rechargeable devices. Even though this technology is smarter and faster than the previous ones, there are still many facets that can be alarming about this technology. With this article, we will dig deeper into how overcharging affects the batteries and what you can do about it.
What if you overcharge rechargeable batteries?Most of us have heard suggestions at some point that we shouldn’t leave phones or laptops plugged with charger overnight. The main reason for this suggestion is the concept of overcharging. In simple words, overcharge can be explained as a phenomenon that occurs when the battery is exposed to the additional current that leads to cell failure. In worst cases, overcharging can also be accompanied by a spontaneous exothermic reaction that decomposes the cathode materials and has the potential to develop in a fire hazard.
When overcharging happens, the charging voltage of the battery is increased above the recommended threshold limit. As a result, the lithium-ions form metallic lithium and builds up at the anode causing lithium plating. The same thing can happen inside the cell as dendrites are created, and it’ll ultimately result in a short circuit. The cell temperature will increase with the short circuit, and the thermal runaway process will get initiated.
We all know that lithium batteries have high energy density. Hence, a lot of energy is stored in a relatively small volume. But once the thermal runaway starts, the battery will catch fire and light up everything that is in direct contact with the battery. Fortunately, the batteries nowadays come with a protective circuit that can cut down the power supply once the cells are fully charged.
Regardless of the circuit, there is another risk of overcharging that is not so severe but has a dire impact on the battery’s lifespan. As you plug the device in a charger, it charges typically up to the maximum limit. After the battery reaches full capacity, the power supply will be cut internally. It means that the device will start discharging for a short amount of time until a significant amount of battery percentage declines (1% to 5%). Due to the discharge, the charger circuit will activate and start charging the device again. Continuing this process will have a negative effect on the battery’s lifespan.
How many times it’s possible to charge a rechargeable battery?A standard lithium-ion rechargeable battery comes with a typical lifespan of 300 to 500 cycles. One cycle consists of full charge and discharge of the battery. But with modern technology, there are batteries available in the market that comes with 800 to 1000 cycles. However, the battery is susceptible to environmental factors as well, which impacts the overall cycles.
A standard battery of 800 cycles will last two good years. Still, it also depends on how often you recharge, use, and overcharge it along with the temperature consistency for the battery. Alongside this, over time, the battery will lose a definitive amount of capacity, and the times you can recharge, it will only reduce.
How do you prevent a rechargeable battery from overcharging?Establishing the fact that battery overcharge is not suitable for the device, we must take every preventive measure possible to avoid this. Although new battery technology is less susceptible to such issues, we still need to take care of them to prolong their life and minimize the potential risks.
Here are some tips that will help you charge the batteries ideally and prevent overcharging much as possible.
1: Don’t Leave the Battery Plugged with Charger
If you think that you can take a stroll when the battery is charging, it’s fine as long as you don’t overdo it. Leaving the battery in such a condition will affect its trickle system or Battery Management System. In some cases, the BMS might fail to prevent the device from overcharging, and it could lead to fire or reduce the battery capacity or both. Considering that batteries suffer from self-discharging as well, charging for a longer duration than necessary will pace up the aging process.
2: Keep the Battery in Right Conditions
Sometimes, it is not the current that breaks the trickle system. It can happen if the battery is damaged physically or kept in inappropriate conditions. For example, assume that you want to store a battery. If you keep it on a shelf insulated from other flammable or hazardous material, it’ll be safe. However, if you throw the battery with metal objects or mishandles it every time you use, the protection circuit will eventually become faulty.
As there is no protection against the unlimited current flow, the battery will overcharge, overheat, and reach the overvoltage level that will further increase its temperature. So, you need to make certain that you keep the battery safely even when you put it away.
3: Don’t Charge It Frequently
Just because the batteries nowadays are rechargeable, that doesn’t mean that you should keep them plugged whenever you want. Many consumers charge the battery whenever the percentage goes below 60% or 50%. But this is not a good thing. A battery must be charged when it reaches around 40% or less. Otherwise, it is absolutely fine to use them. Plugging them into a charger only disrupts the regular charging cycle.
Along with these points, you should also remember to keep the battery in appropriate temperature conditions, pick the right charging method, and use them carefully. Handling them with care is how you can prevent any accident from happening.