March 14, 2024
Battery memory effect: uncovering the invisible enemy of battery life
In our daily lives, batteries are an indispensable source of energy. Whether it’s smartphones, laptops, electric motorcycles, or electric cars, they all rely on batteries to provide power, and the performance of the battery directly affects the user experience of the device. However, batteries are influenced by various factors during the charging and discharging process, among which the memory effect is a phenomenon that cannot be overlooked.
Understanding the causes of this effect and how to address it can effectively extend the lifespan of batteries and improve their performance. This article will explore the principles of the battery memory effect, the types of batteries that are prone to it, and how to effectively deal with this phenomenon.
Table of Contents
Add a header to begin generating the table of contents
What is the memory effect of batteries?
The memory effect of batteries refers to the phenomenon where certain rechargeable batteries (secondary batteries) experience a gradual decrease in actual capacity and operating voltage after repeated shallow charge and discharge cycles.
When a battery is partially discharged and then fully recharged, it seems to “remember” this lower discharge level and will stop supplying power even if there is remaining capacity in subsequent uses.
This situation leads to a reduction in the effective capacity of the battery, thereby shortening the operating time of the device. For users, this translates to a shorter effective usage time and increased charging frequency.
Scientific explanation of the battery memory effect
The battery memory effect is primarily caused by the incomplete reversal of chemical reactions within the battery.
Taking nickel-cadmium (NiCd) batteries as an example, if the battery is recharged without being fully discharged, the NiOOH in the positive electrode material may not fully convert to the low-resistance β-Ni(OH)2 but instead forms high-resistance γ-NiOOH, which increases the internal resistance of the battery and reduces the operating voltage.
Additionally, cadmium grains in the negative electrode may agglomerate, forming a secondary discharge plateau that further exacerbates the battery memory effect.
Practical effects of the battery memory effect on users
The battery memory effect impacts users mainly in the following aspects.
- Shortened device runtime: The reduction in battery capacity means the device cannot maintain its original operating time.
- Sudden power loss: The battery memory effect may cause the battery to prematurely reach the discharge termination voltage, leading to unexpected shutdowns of the device.
- Increased long-term costs: Frequent battery replacements or maintenance increase the overall ownership cost for users.
Which secondary batteries are prone to the battery memory effect?
- Nickel-Cadmium Batteries (NiCd)
NiCd batteries are one of the earliest widely used rechargeable batteries, and their battery memory effect is the most severe. Their structural characteristics cause the battery to charge when not fully discharged, leading to the agglomeration of cadmium crystals and forming a lower discharge plateau. Over long-term use, this continually reduces effective capacity.
NiMH batteries do not exhibit significant battery memory effects as readily as NiCd batteries, but similar phenomena may occur under specific conditions. Compared to NiCd batteries, the battery memory effect in NiMH batteries is milder, but users should still be aware of the damage caused by shallow charging.
Batteries that may experience memory effect
- Lead-Acid Batteries
The battery memory effect in lead-acid batteries is relatively mild, but improper charging and discharging can also lead to capacity degradation, especially when the battery is not fully charged. This is manifested as sulfation, where lead sulfate crystals form inside the battery, causing performance degradation.
- Lithium-Ion Batteries (Li-ion)
Comparing lead acid battery to lithium ion , although typically considered unaffected by the battery memory effect, mainly because the chemical properties and manufacturing processes of lithium-ion batteries make them less prone to battery memory effects, slight capacity degradation may still occur under specific conditions.
How to mitigate the battery memory effect
To alleviate or eliminate the battery memory effect, the following measures can be taken.
- Correct Charging and Discharging: For NiCd batteries, try to achieve deep discharge before recharging; for other types of batteries, avoid battery over discharge.
- Use Smart Chargers: Modern chargers can monitor battery status and use appropriate charging strategies.
- Regular Maintenance: Regularly checking and calibrating the battery ensures it remains in good condition.
- Maintain Suitable Conditions: Avoid extreme conditions such as high or low temperatures, which can accelerate battery aging.
Unveiling battery memory effect — how to charge and discharge correctly?
For lithium batteries, although they do not have a traditional battery memory effect, certain best practices can help extend their lifespan and improve lithium battery safety:
- No Activation Needed: New lithium batteries do not require special activation routines; normal usage is sufficient.
- Avoid Overcharging and Deep Discharging: Do not wait until the battery is completely drained to recharge, and avoid prolonged overcharging.
- Proper Storage: For lithium batteries that are not frequently used, it’s recommended to keep them at a half-full state and recharge periodically.
Conclusion
The battery memory effect is a complex issue, particularly evident in early nickel-cadmium and nickel-metal hydride batteries. With advancements in technology, especially the widespread use of lithium-ion batteries, the impact of the battery memory effect has significantly diminished.
Understanding different types of batteries and their characteristics, along with adhering to correct usage and maintenance guidelines, can help maximize battery efficiency and lifespan while ensuring safety.
Who are we
Tycorun, a prominent player in the battery-swapping industry, specializes in developing and manufacturing battery swap station and lithium-ion batteries. The company aims to offer sustainable energy solutions for electric vehicles.
Tycorun has made significant inroads into the Chinese market, primarily targeting urban regions where the need for electric two-wheelers is substantial. The company consistently allocates resources to research and development to improve its battery technology and broaden its network of swapping stations.
The battery swapping stations created by Tycorun are both user-friendly and efficient. Their lithium-ion batteries are renowned for their high energy density and long-lasting performance, suitable for different models of electric two-wheelers.
Additionally, Tycorun offers comprehensive software solutions for monitoring and managing our batteries.
Related post
October 2, 2023
September 19, 2023
Willow
Willow is a materials engineer with a Master’s degree in Materials Science and Engineering, specializing in lithium-ion battery materials and energy storage technologies.
Her work focuses on EV battery swapping solutions, battery innovation, and new energy industry trends, aiming to translate research insights into practical applications for sustainable transportation.
Leave a comment