As the world transitions to clean energy and sustainable sources, lithium-ion (Li-ion) batteries are becoming increasingly popular. These batteries, with their high energy density and long lifespan, have revolutionized the battery industry. However, one question many users ask is: "How long do lithium-ion batteries last?" In this article, we'll explore this question and examine how LiFePO4 batteries, an advanced type of lithium-ion battery, perform in terms of lifespan.
Part 1: What are lithium-ion batteries?
Lithium-ion batteries, including lithium iron phosphate (LiFePO4) batteries, are rechargeable batteries that use lithium ions as the main component of their electrolyte. LiFePO4 batteries offer several advantages over other battery types, including longer lifespan, higher efficiency and energy density, reduced maintenance requirements, safety, and environmental friendliness. These characteristics make them ideal for off-grid power systems, high-performance applications, and mobility applications.
Lithium-ion batteries are frequently used as starter batteries in vehicles due to their high energy density and low weight. They are well-suited for this application because they can deliver a short pulse of high current to start the engine. Lithium-ion batteries used as starter batteries typically have a lower capacity and should not be deeply discharged to avoid damage.
In contrast, LiFePO4 batteries are excellent deep-cycle batteries. They can withstand frequent deep discharges, making them ideal for renewable energy storage and other deep-cycle applications. They have a longer cycle life than lithium-ion batteries and can deliver high power over extended periods. Learn more about the differences between these two battery types at LiFePO4 vs. Lithium-ion Batteries: Which Battery Should You Choose?
Part 2: How long do lithium-ion batteries last?
A standard lithium-ion battery lasts an average of 2-3 years, depending on usage. However, this lifespan can be extended to up to five years if the battery is well-maintained and used according to the manufacturer's instructions. Lithium-ion batteries are also temperature-sensitive, and high temperatures can significantly shorten their lifespan. It is important to store your lithium-ion battery in a dry and cool place to avoid heat exposure and extend its lifespan.
LiFePO4 batteries are a more advanced and sustainable type of lithium-ion battery that is becoming increasingly popular in the battery industry. These batteries have a longer lifespan than conventional lithium-ion batteries, up to 10 years or more. LiFePO4 batteries are also extremely stable and safe, representing a more reliable and sustainable solution for off-grid power and mobility applications.
A key advantage of LiFePO4 batteries is their ability to handle more charge and discharge cycles. While standard lithium-ion batteries can withstand 500-1000 cycles, LiFePO4 batteries can handle up to 2000 cycles, making them a more durable and cost-effective solution in the long run. Litime's LiFePO4 batteries can have a lifespan of 4000-15000 cycles, allowing for a service life of more than 10 years, and are the perfect alternative to lead-acid batteries. Furthermore, LiFePO4 batteries are much safer than conventional lithium-ion batteries because their chemical composition makes them less prone to overheating or explosions.
LiTime offers high-quality LiFePO4 batteries designed for longer lifespan, higher efficiency, and sustainability. One popular model is the 12V 100Ah LiFePO4 battery, which is ideally suited for various off-grid power and mobility applications. We offer a range of battery sizes and capacities to meet diverse requirements. LiTime prides itself on the quality and longevity of its batteries, which are thoroughly tested to ensure customer satisfaction.
Part 3: Factors influencing the lifespan of lithium-ion batteries
According to the study: A STUDY OF THE FACTORS THAT AFFECT LITHIUM ION BATTERY DEGRADATION These are the factors that can influence the lifespan of lithium-ion batteries.
3.1 During storage
1) Temperature
The main cause of battery capacity loss during storage is temperature, with higher temperatures leading to thermal decomposition of the electrodes and electrolyte.
The decomposition of the electrolyte increases the solid electrolyte interface (SEI) layer thickness on the anode, thereby consuming lithium ions, increasing the cell's internal resistance (IR), and reducing battery capacity. This decomposition process also produces gases that increase internal pressure and pose a safety risk. As shown in Table 3.1, lithium-ion batteries stored at the same state of charge (SOC) (40%) lose different percentages of their capacity over the course of a year at varying temperatures.
The degree of degradation increases with higher temperatures. Furthermore, extreme temperatures significantly accelerate capacity loss. A temperature increase from 0°C to 25°C results in only a 2% increase in capacity loss, while an increase of 20°C from 40°C to 60°C causes a 10% capacity loss.
Temperatures above 30°C are considered stressful for lithium-ion batteries and can lead to a significant reduction in calendar life. To extend battery life, it is advisable to store lithium-ion batteries at temperatures between 5°C and 20°C.
2) State of Charge (SOC)
In lithium-ion batteries, the open-circuit voltage (OCV) increases with increasing state of charge (SOC), as shown in Figure 3.2. During storage, a higher SOC of the battery leads to a higher OCV. However, a high OCV can lead to growth of the solid electrolyte interface (SEI) and trigger electrolyte oxidation in Li-ion batteries, resulting in capacity loss and increased internal resistance (IR).
The image shows the different degradation rates of lithium-ion batteries at various state-of-charge (SOC) values over a ten-year storage period. The remaining capacity of lithium-ion batteries decreases more rapidly with increasing SOC value.
3.2 While cycling
1) Temperature
While a higher temperature during battery operation can temporarily improve battery performance, prolonged cycling at high temperatures shortens the battery's lifespan. A battery operating at 30°C will have a 20% shorter lifespan, while at 45°C it will only last half as long as at 20°C.
Manufacturers specify a nominal operating temperature of 27°C for batteries to extend their runtime. Conversely, extremely low temperatures increase the battery's internal resistance and reduce its discharge capacity.A battery that offers 100% capacity at 27°C will only have 50% capacity at -18°C.
The discharge capacity of lithium-polymer cells discharged at different temperatures exhibits a fluctuation, with the capacity of the batteries being lower at low temperatures (0°C, -10°C, -20°C) than at higher temperatures (25°C, 40°C, 60°C). Furthermore, charging lithium-ion batteries at low temperatures (below 15°C) leads to lithium plating due to the slowed incorporation of lithium ions, which accelerates the degradation of lithium-ion batteries by increasing the battery's internal resistance and further reducing its discharge capacity.
To maximize the lifespan and performance of lithium-ion batteries, it is recommended to operate them at moderate temperatures. A temperature of 20°C or slightly below is optimal for lithium-ion batteries to achieve their maximum lifespan. However, manufacturers recommend a slightly higher temperature of 27°C for lithium-ion batteries when maximum battery life is required.
2) Depth of the drain
Deep discharge has a decisive impact on the lifespan of lithium-ion batteries. Deep discharges cause pressure within the lithium-ion cells and damage the negative electrodes, accelerating capacity loss and potential cell damage. As illustrated in the figure, the higher the cycle DOD, the shorter the battery's lifespan.
Depths of discharge exceeding 50% are classified as deep discharges. When the charge of a lithium-ion battery drops from 4.2 V to 3.0 V, approximately 95% of its energy is consumed, and continuous discharge leads to a significantly shorter battery lifespan. To avoid capacity loss, complete discharge should be avoided during the cycle of a lithium-ion battery. Partial discharge and recharge of lithium-ion batteries is recommended to extend their lifespan.
Manufacturers typically use the 80% DOD formula to rate a battery, meaning that only 80% of the supplied energy is used during operation, while the remaining 20% is reserved for extending battery life. Reducing the DOD value can extend the lifespan of lithium-ion batteries, but too low a DOD value can lead to insufficient battery life and the inability to perform certain tasks. It is recommended to maintain a DOD value of approximately 50% when using lithium-ion batteries to achieve maximum battery life and optimal operating time.
3) Charging voltage:
Lithium-ion batteries can achieve high capacity and long runtime with a high charging voltage. However, it is not recommended to fully charge lithium-ion batteries, as this can lead to lithium plating, which results in capacity loss and potentially damages the battery, potentially causing fires or explosions.
The image above shows the capacity reduction at high charging voltages (> 4.2 V/cell), with higher voltages leading to faster capacity loss and a shorter lifespan. A charging voltage of 4.2 V is the recommended voltage level for optimal capacity according to safety standards for lithium-ion batteries. A reduction in charging voltage of 70 mV decreases the overall capacity by approximately 10%.
The table below also shows that the cycle life is longest at a charging voltage of 3.90 V (2400-4000) and is halved with each increase in the charging voltage of 0.10 V in the range of 3.90 V-4.30 V.
Lithium-ion batteries should be charged at a voltage below 4.10 V to avoid significant battery degradation. While a lower charging voltage extends the battery's lifespan, it provides the user with a shorter runtime. Furthermore, discharging below 2.5 V per cell should be avoided, and the optimal charging voltage for maximum lifespan is 3.92 V. For this reason, LiTime does not recommend charging LiFePO4 batteries with a standard lead-acid charger, as the voltage is not high enough for charging. Below is the recommended charging voltage format for various deep-cycle battery systems.
Electronic devices such as laptops and mobile phones have a high voltage threshold to achieve optimal battery life. However, for large energy storage systems used in satellites or electric vehicles, the voltage threshold is set lower to extend battery life. Regardless of the application, overcharging lithium-ion batteries can significantly shorten their lifespan and cause fires or explosions, so caution is advised.
4) Charging current/C-rate:
Lithium-ion batteries experience several negative effects at high C-rates, such as increased internal resistance, loss of available energy, safety concerns, and irreversible capacity loss.
One of the main consequences of high C-rates is lithium plating. When a lithium-ion battery is charged with a high current, the lithium ions move rapidly, leading to an accumulation of lithium ions on the anode surface and the formation of metallic lithium. This process is accelerated when batteries are fast-charged at low temperatures and high states of charge (SOC).
This lithium layer can transform into a dendritic form under the influence of gravity, leading to increased self-discharge of the battery. In extreme cases, this can cause a short circuit and potential fires. Furthermore, high charging and discharging currents also result in greater energy losses, as the battery's internal resistance converts energy into heat. If the C-rate exceeds the battery's recommended value, the elevated internal temperature can cause stress, damage the battery, and accelerate capacity loss.
5) Cycle frequency
Frequent cycling of lithium-ion batteries, especially when used four or more times per day, can lead to mechanical stress and increase the growth of the solid electrolyte interlayer (SEI).
During cycling, lithium-ion batteries lose both positive and negative lithium reaction sites on their electrodes, thus reducing their capacity. The buildup of the SEI layer during cycling increases the battery's internal resistance and reduces its electronic conductivity and chargeability.
The thickening of the SEI layer, the decrease in the number of Li centers, and other chemical changes in Li-ion batteries lead to capacity loss and eventually battery failure. Although there is no published research directly addressing this topic, it is assumed that a high cycle frequency accelerates battery degradation due to the high temperatures generated by frequent use.
If lithium-ion batteries are constantly operated cyclically without sufficient time to cool down, this can lead to chemical stress, resulting in the decomposition of the electrolytes and electrodes.
Part 4: Methods for extending the lifespan of Li-ion batteries
- Store the battery at a moderate temperature: High temperatures can shorten the battery's lifespan. It is therefore recommended to store or use lithium-ion batteries within a moderate temperature range of 5°C to 20°C.
- Partial discharge and recharge: Partially discharging and recharging lithium-ion batteries can extend their lifespan. Avoiding deep discharges above 50% depth of discharge (DOD) can also contribute to extending battery life.
- Maintain moderate state of charge (SOC): Extreme SOC levels can lead to capacity loss and shorten battery life. Keeping lithium-ion batteries at a moderate SOC level minimizes battery wear and extends battery life.
- Avoid exposure to heat: High temperatures during use or storage of batteries can increase the thickness of the SEI and trigger electrolyte oxidation, leading to capacity loss and a shortened battery lifespan.
- Store batteries correctly when not in use: Store lithium-ion batteries at approximately 50% SOC when not in use and protected from extreme temperatures and humidity.
- Avoid fast charging and discharging: Fast charging or discharging can lead to excessive heat generation, which over time can damage the battery's internal components and shorten its lifespan.
- Use OEM (Original Equipment Manufacturer) chargers: Using OEM chargers, which are specifically designed for lithium-ion batteries, ensures they are charged at the correct voltage and current to prevent damage and extend their lifespan. LiTime offers suitable LiFePO4 chargers for charging LiFePO4 lithium batteries.
Conclusion
This article describes in detail the concepts related to lithium batteries, factors that affect lithium batteries, and how to extend their lifespan. We hope it helps you understand lithium batteries better. If you want to find the right lithium battery, you can consult the official [website/document/etc.]. LiTime website Visit us to learn more about the relevant products and other information.
