Lithium battery aging: mechanism, impact and delay strategy

As the core energy source of today’s electronic devices and electric vehicles, the performance and life of lithium batteries directly affect our lives and travel. However, lithium batteries are not permanent energy storage devices. As time goes by, their performance will inevitably decline, which is what we often call “aging”. This article delves into the mechanisms behind lithium battery aging, the impacts it causes, and how to effectively slow down the aging process.

Mechanism of lithium battery aging

What is lithium battery aging?

Lithium battery aging, in simple terms, refers to the process in which the performance of the battery gradually deteriorates as the battery is used for a longer time. This degradation is manifested as a decrease in capacity, an increase in battery internal resistance, a decrease in charging and discharging efficiency, and an increase in heat generation, which ultimately shortens the battery life and even makes it impossible to use it normally.

Why do lithium batteries age?

Lithium battery aging is a complex multi-factor process. It is not caused by a single reason, but the result of multiple factors. These factors can be roughly divided into the following categories:

Cycle aging

This is one of the main causes of lithium battery aging. Each charge and discharge cycle is accompanied by the insertion and extraction of lithium ions between the positive and negative electrode materials. This process is not completely reversible, and repeated cycles will cause microscopic changes in the structure of the electrode material, such as:

Negative graphite material: Repeated insertion and extraction of lithium ions will cause the destruction of the graphite layered structure, forming cracks and gaps, reducing the diffusion efficiency of lithium ions, and ultimately reducing the capacity of the battery.

Positive electrode material: Positive electrode material also undergoes volume changes during the charge and discharge process, resulting in the breakage of material particles, loss of active substances, reduced electrochemical activity, and ultimately affecting battery performance.

Solid electrolyte interface film (SEI film): A layer of SEI film will form on the surface of the negative electrode, which can protect the negative electrode, but its growth is not completely stable. Continuous charge and discharge will cause the SEI film to continue to thicken, consume lithium ions in the lithium battery electrolyte, and reduce the battery capacity.

Calendar aging

Even if the lithium battery is idle, its performance will decay over time, which is calendar aging. The main reasons include:

Self-discharge: Even if the lithium battery is not in use, it will slowly discharge spontaneously, which will consume the battery’s energy and accelerate certain side reactions.
Electrolyte decomposition: The electrolyte will slowly decompose during storage, producing some byproducts that affect the electrochemical performance of the battery.
Internal side reactions: Some slow side reactions will occur between the materials inside the battery, which will consume active substances and reduce the battery capacity.
Environmental factors: Environmental factors such as temperature and humidity can also accelerate calendar aging. High temperature can accelerate electrolyte decomposition and side reactions, while high humidity can increase corrosion inside the battery.

Overcharge and over-discharge

Battery overcharge can cause electrolyte decomposition, generate gas, increase internal pressure of the battery, and even cause safety accidents. Over-discharge can damage the negative electrode material, resulting in irreversible loss of battery capacity.

High temperature environment

High temperature can accelerate electrolyte decomposition, SEI film growth, and other side reactions, significantly shortening battery life.

Fast charging

Although fast charging can save time, it will generate a large current, causing the internal temperature of the battery to rise, aggravating the aging of the electrode material.

High current discharge

Frequent high current discharge can also increase the heat generation inside the battery and aggravate battery aging.

Defects of the battery management system (BMS)

The role of the BMS is to monitor and manage the operating status of the battery. If the BMS fails, it may cause problems such as overcharge, over-discharge or overheating, accelerating battery aging.

Impact of lithium battery aging

Aging of lithium batteries can bring many negative effects:

Capacity decay: This is the most direct impact. The capacity of an aged battery will gradually decrease, shortening the battery life of the device.
Performance degradation: In addition to the reduced capacity, the battery’s performance indicators such as charging speed and discharge power will also decrease.
Increased internal resistance: Aging will cause the internal resistance of the battery to increase, thereby reducing charging efficiency and increasing heat generation.
Safety hazards: Severe battery aging may cause safety accidents such as internal short circuits, fires, and even explosions.
Shortened life: Battery aging ultimately shortens its service life and requires more frequent battery replacement.

How to prolong lithium battery life?

Although lithium battery aging is inevitable, we can use some methods to slow down its aging speed and extend its service life:

Reasonable charging habits

Avoid deep charging and discharging: Try to keep the battery power between 20% and 80%, and avoid frequent deep charging and discharging (explore lithium battery charging).
Use a suitable charger: Use an original or compliant charger to avoid overcharging and over-discharging.
Control charging current: Try to use slow charging and avoid frequent fast charging.

Control ambient temperature

Avoid high temperature environment: Avoid exposing the battery to high temperature, especially in hot summer weather. Do not place the device in direct sunlight or in a high-temperature car for a long time.
Avoid low temperature environment: Low temperature environment will also affect battery performance. Try to avoid using and storing batteries in low temperature environment for a long time.

Regular maintenance

Regular inspection: Regularly check the appearance of the battery to see if there are any abnormalities such as leakage and swelling (explore swollen battery).
Regular charge and discharge: For batteries that are not used for a long time, it is recommended to perform a complete charge and discharge cycle every once in a while to activate the battery.

Optimize usage habits

Avoid frequent sudden acceleration and sudden braking: For electric motorcycles, avoid frequent sudden acceleration and sudden braking, which will increase the burden on the battery and accelerate aging.
Reduce high current discharge: Try to avoid long-term high current discharge.

Use technical means

Battery Management System (BMS): Advanced BMS can effectively monitor and manage the operating status of the battery to prevent problems such as overcharging, over-discharging and overheating.
Battery preheating function: In low temperature environments, using the battery preheating function can improve battery performance and reduce the impact of low temperature on the battery.

Conclusion

Lithium battery aging is a complex process with many influencing factors. By understanding its aging mechanism and influencing factors and taking reasonable measures, we can effectively slow down the aging speed of lithium batteries, extend their service life, improve their safety, and maximize their role.

FAQ

What causes lithium batteries to age?

Lithium batteries age due to chemical and structural changes inside the battery over time. Major factors include charge/discharge cycles (cycle aging), time-related degradation (calendar aging), exposure to high temperatures, overcharging, deep discharging, and high current usage.

How long do lithium batteries last before they start aging?

Most lithium batteries start showing signs of aging after 300–500 full charge cycles or around 2–3 years of typical use. However, this depends on usage habits, storage conditions, and battery quality.

How do I know if my lithium battery is aging?

Common signs of aging include:

Reduced capacity (shorter run time)
Slower charging
Device heats up during use or charging
Increased internal resistance
Sudden battery drops or shutoffs

Can battery aging be reversed?

No, battery aging is irreversible. Once the internal materials degrade, performance loss is permanent. However, proper use can slow down the aging process significantly.

Does fast charging damage lithium batteries?

Yes. Fast charging increases internal temperatures and puts more stress on battery materials, which can accelerate aging. Occasional fast charging is fine, but daily use may shorten battery lifespan.

Is it better to keep my battery between 20% and 80%?

Yes. Keeping the state of charge (SoC) within the 20–80% range minimizes stress on the battery and extends its overall lifespan. Avoiding full charge/discharge cycles is a well-known best practice.

Chase Wu

Chase is an industry expert and independent analyst specializing in electric two- and three-wheeler battery swapping systems. His expertise spans lithium-ion battery technology, intelligent battery swapping infrastructure, and electric mobility applications, with a strong focus on real-world deployment, market dynamics, and long-term industry development.

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