Lithium-ion batteries are ubiquitous. They power our smartphones, laptops, electric vehicles, and many other devices we use every day. But how much do you know about them? In this blog, we will help you understand everything about lithium-ion batteries.
What are lithium-ion batteries? How do they work? Lithium-ion batteries (referred to as Li-ion batteries for short) are rechargeable batteries that use lithium ions as the main charge carrier. They are commonly used in various devices, including smartphones, laptops, electric vehicles, and are increasingly used in solar energy systems.
This gives it better thermal stability and safety. During the charging and discharging cycles, lithium ions are inserted into or extracted from the cathode material. Phosphate ions make the battery itself more stable and have a lower risk of thermal runaway. Common applications: electric vehicles (EV), solar energy storage, and power tools.
Why choose LiFePO₄? Known for its excellent thermal stability and safety, it is less likely to overheat or catch fire compared to other lithium batteries. These batteries also have a longer cycle life, usually exceeding 2,000 charge cycles. The materials used – iron and phosphate – are more abundant and environmentally friendly than cobalt or nickel. Disadvantage: The energy density of LiFePO₄ batteries is lower than that of LiCoO₂, so they are larger in volume and heavier in weight when storing the same amount of energy. The nominal voltage of LiFePO₄ batteries is about 3.2V, so more batteries are needed to achieve the same voltage output as other lithium chemistries. Although LiFePO₄ is usually cheaper than LiCoO₂, it is still more expensive than traditional lead-acid batteries. Lithium Manganese Oxide (LiMn₂O₄): LiMn₂O₄ adopts a spinel structure, in which manganese ions are arranged in a three-dimensional lattice, making it easier for lithium ions to pass through the material. Manganese is cheaper and more abundant than cobalt, but its energy density is also lower. During the charging and discharging process, lithium ions move between the cathode and anode, but the manganese oxide structure provides good stability and safety during the cycle. Common applications: power tools, electric bicycles, hybrid electric vehicles (HEV), and some electric vehicles. Why choose LiMn₂O₄? It has excellent heat resistance and reduces the risk of overheating or thermal runaway. Manganese is more abundant and cheaper than cobalt, so these batteries are more affordable than those based on LiCoO₂. LiMn₂O₄ batteries can provide a high discharge rate, making them ideal for applications that require explosive power. Disadvantage: Like LiFePO₄, the energy density of LiMn₂O₄ batteries is lower than that of LiCoO₄, which means they need more space to store the same amount of energy. Although LiMn₂O₄ is more durable than LiCoO₄, its cycle life is still shorter than that of LiFePO₄, especially in cases of frequent use. Although LiMn₂O₄ is more thermally stable than LiCoO₄, it still experiences capacity loss if exposed to high temperatures for a long time. Nickel Manganese Cobalt (NMC): NMC chemistry combines nickel (provides energy density), cobalt (stabilizes the battery and extends service life), and manganese (improves safety and thermal stability).The exact proportions of nickel, manganese, and cobalt can vary depending on the desired characteristics. During the charging and discharging cycles, lithium ions intercalate and deintercalate between the cathode and anode. This gives NMC batteries a high energy density and a relatively long service life. Common applications: electric vehicles (EVs), grid energy storage, and power tools. Why choose NMC batteries? They achieve a perfect balance between high energy density and safety, making them the preferred choice for electric vehicles (EVs) and large-scale energy storage systems. NMC batteries have a long cycle life, usually exceeding 1,000 cycles depending on the specific formulation, so they are durable. Disadvantages: NMC batteries are usually more expensive than LiFePO₄ and LiMn₂O₄ because of the higher cost of nickel and cobalt. Their production process is more complex, which may lead to unstable quality. Like LiCoO₂, NMC also uses cobalt, which raises concerns about supply chain sustainability and ethical mining practices. Nickel cobalt aluminum oxide (NCA): The chemical composition of NCA batteries uses a combination of nickel, cobalt, and aluminum oxides. The main advantage is high energy density, which is very suitable for applications such as electric vehicles (EVs). Adding aluminum stabilizes the battery and prevents it from degrading over time. The energy density of NCA batteries is slightly higher than that of NMC, but due to the use of cobalt and nickel, the price is higher. The chemical reaction is similar to NMC, in which lithium ions move between the cathode and anode. Common applications: electric vehicles (EVs), especially those produced by companies like Tesla. Why choose NCA batteries? They are one of the lithium chemical batteries with the highest energy density. Compared with LiCoO₂ and other lithium chemical batteries, they have a longer cycle life and are more cost-effective in the long run. The thermal stability of NCA batteries is better than that of LiCoO₂, but not as good as that of LiFePO₄. Disadvantages: NCA batteries are expensive because of the use of nickel, cobalt, and aluminum, which leads to a higher overall cost. Like NMC, the use of cobalt raises concerns about environmental impact and ethical procurement practices. Lithium titanate (Li₂TiO₃): Li₂TiO₃ has a spinel structure similar to LiMn₂O₄ but contains titanium ions. This material has a very stable lattice, so it can be charged and discharged at an extremely fast speed, very suitable for applications that require fast charging. Compared with other chemicals, it also has a very long service life and can be charged many more times. However, its lower energy density makes it less suitable for applications where space and weight are crucial.
Common Applications: Rapid charging applications, buses, and high-power energy storage systems.
However, the energy density of Li₂TiO₃ batteries is significantly lower compared to other lithium-chemistry batteries, limiting their applicability in energy-intensive applications such as electric vehicles or consumer electronics. Due to their advanced technology and materials, these batteries are more expensive than other lithium batteries.
Are Lithium-ion Batteries Best for Solar Energy? Lithium-ion batteries are not the cheapest option, but they are the best choice for solar energy storage due to their performance and long-term value.
Other Battery Options for Solar Energy Storage: Lead-Acid Batteries Traditionally, lead-acid batteries have been used for solar energy storage due to their lower upfront costs. However, they have lower energy density, shorter lifespans (3-5 years), and require more maintenance, making them less suitable for modern solar systems.
Flow Batteries Flow batteries are a newer technology with a longer cycle life, particularly suitable for large-scale storage. However, they tend to be larger, have lower energy density, and are more expensive than lithium-ion batteries.
Sodium-ion Batteries Sodium-ion batteries, due to the abundance and lower cost of sodium compared to lithium, are becoming potential alternatives to lithium-ion batteries, offering lower costs and greater sustainability. They are not yet widely used and are still in the development phase for solar applications.
How to Safely and Effectively Use and Maintain Lithium-ion Batteries Lithium-ion batteries have a limited lifespan, with their performance and capacity declining over time and use. However, by following some best practices, you can help extend their lifespan and efficiency. Avoid Overcharging Never charge lithium-ion batteries beyond their recommended voltage, nor leave them plugged into the power source for extended periods after being fully charged. Overcharging can cause the battery to overheat, swell, or even explode. To prevent this, use smart chargers that stop charging automatically once the battery is full, or manually disconnect the charger when the battery reaches 80%-90% capacity.
Preventing Overheating: Exposure of lithium-ion batteries to high temperatures, such as direct sunlight, fire, or hot surfaces, can lead to dangerous thermal runaway, leakage, or explosion. Ensure that these batteries are stored and used in a cool, dry environment, and avoid using them in conditions that are excessively hot or cold. Avoid Deep Discharge: Refrain from reducing the discharge voltage of lithium-ion batteries below the minimum voltage or allowing them to be completely depleted. Doing so may result in permanent damage, such as reduced capacity, increased internal resistance, or complete failure. When the battery capacity drops to approximately 20%–30%, recharge the battery or use a protective circuit to prevent over-discharge. Solar Energy Storage with Lithium-ion: If you plan to use lithium-ion for solar energy storage at home, we can offer you a range of home energy storage products, allowing you to obtain the best pricing and plans.