Lithium Ion Battery Pack
Lithium-ion batteries are one of the most popular types for consumer electronics and have also become a staple for portable power tools, electric vehicles and energy storage systems. Lithium Nickel Manganese Cobalt Oxide systems have different names like NMC, NCM, CMN and MNC but are all basically the same.
They offer superior cycle life and power & energy density in comparison to their competitors. A single cell has a voltage of 3.7 volts but multiple cells can be connected in series to achieve different voltages.
High Energy Density
Lithium ion battery packs are highly efficient and offer superior energy densities. They are widely used in portable electronic devices like laptops and cell phones and electric vehicles and are making significant contributions to reducing the use of fossil fuels for transportation.
Batteries with high energy density allow longer run times and range while also lowering the weight of the device. This makes them ideal for devices that require extended operation periods or frequent recharging such as hybrid cars and drones. Battery packs for these applications undergo specialized engineering to meet high power and capacity requirements.
The maximum energy density of lithium ion batteries is determined by the amount of lithium ions that can be stored within each electrode. The lithium ions are stored in graphite anodes by a process called intercalation, where they are physically inserted between the 2D layers of graphene in the bulk material. This method of storage allows for a much higher capacity than previous anode materials such as nickel cobalt aluminum oxide, lithium iron phosphate or nickel manganese cobaltate.
Other technologies for storing lithium ions, such as solid-state electrolytes (SSE), are being developed and are expected to offer further increases in energy density. These are designed to eliminate the need for a porous separator and could reduce battery cost. Detailed modeling of these new materials is needed to understand their performance and safety.
Long Lifespan
Modern lithium ion battery packs are engineered for a long lifespan. Manufacturers typically specify a cycle life of 300 to 500 discharge/charge cycles for small wearable batteries. Higher quality industrial battery packs deliver even more cycles for greater productivity during work shifts.
Battery performance is affected by internal resistance and self-discharge rates. However, the most important factor in determining the life of a lithium-ion battery is temperature and how fast it cycles. Exposure to elevated temperatures decreases the longevity of lithium-ion batteries by preventing efficient ion exchange between electrodes and electrolytes.
Keeping a Lithium-ion battery at a high state of charge (SoC) during storage will also reduce lithium ion battery pack longevity. Generally, a battery should be stored at 50% SoC or less to ensure it retains the maximum available capacity while not in use.
Every 0.10V drop in peak charge voltage lowers a battery’s cycle life by 10%. A good guideline is to charge the battery as close to its peak voltage as possible during regular use.
Lithium-ion battery cells require the critical minerals cobalt and graphite for manufacture. When these batteries are recycled correctly, rather than thrown away, they can be reclaimed and reused to power new devices. That helps conserve these scarce resources, while protecting the environment. When discarded, these batteries can cause serious harm to the environment by polluting water and soil with toxic heavy metals.
Low Self-Discharge Rate
When a battery sits idle for long periods of time, it may lose some of its capacity. This is known as battery self-discharge and is a normal part of the lifespan of any rechargeable battery. It is important to keep in mind that lithium batteries should be charged frequently and not left completely depleted. Leaving lithium batteries at a premier charge level (between 30% and 80%) can greatly reduce the rate of self-discharge and help them maintain their overall health over the years.
Battery self-discharge occurs mainly through an irreversible reaction with the electrolyte. lithium ion solar battery The reaction produces an insoluble compound that prevents the positive electrode material from absorbing lithium ions, thereby decreasing its power and capacity.
The self-discharge rate is highly dependent on the temperature, with lower temperatures causing batteries to discharge faster. Battery quality is also important, with first-rate manufacturing techniques and materials offering reduced self-discharge rates.
A battery that exhibits a high rate of self-discharge is at higher risk of internal short circuits. As such, it is critical to perform regular battery cell and battery self-discharge testing to assess the health of batteries.
Safety
While a lithium ion battery pack can be used in most devices and power electric vehicles, it is important to note that these batteries are extremely hazardous and may catch fire or explode if misused. This is due to the fact that they are highly sensitive and inherently unstable at high temperatures. Heat related battery failures are usually a result of physical abuse or improper use, charging, discharging, or storage.
Luckily, lithium-ion battery packs are designed with several layers of protection to prevent thermal runaway and other safety hazards. These include vents to release gasses and a circuit board that regulates energy flow. Additionally, a backup fuse or thermostat is often added to these packages to help protect against catastrophic failure. If any of these fail, the battery will rapidly heat up in a process known as thermal runaway and may explode or catch fire.
To minimize your risk, always purchase devices and chargers with the Underwriters Laboratories mark and only use them as instructed by the manufacturer. Also, be sure to store your devices and chargers in a cool, dry place away from children and pets. In addition, only charge your devices with a UL certified cord and power adapter. Lastly, if your device or battery begins to feel hot or smell burnt, discontinue use immediately and contact the manufacturer for proper handling instructions.
