Lithium Battery Pack
Lithium battery packs contain multiple lithium cells wired together to deliver a specific voltage and power capacity. They are designed with specialized electronics to prevent overheating and fire.
This technology powers the devices we use every day, from laptops and cell phones to hybrid cars and power tools. We take it for granted, but lithium-ion battery chemistry is quite remarkable.
Battery Size
The base building block of any battery pack is the lithium-ion cell. Li-ion cells come in a variety of sizes, formats and chemistries, each with unique performance characteristics that influence the lifespan, runtime, power capacity, temperature performance, cycle life and load currents of a final battery pack.
Popular small lithium-ion cylinder cells include the 18650 cell, which is just slightly larger than an AA battery and often used in high drain devices such as flashlights. Other common cell sizes include the 20700, 2254, 2732 and 26650.
Unlike lead-acid batteries, lithium-ion cells do not need to be fully discharged before being recharged. This feature reduces machine downtime while Li-ion battery pack the battery charges and makes cleaning and maintenance procedures more straightforward.
In addition, the fast charging speed of lithium-ion cells allows a battery pack to be opportunity charged, further reducing downtime and increasing productivity. Moreover, lithium-ion batteries can typically be opportunity charged up to 50 times more than traditional lead-acid batteries, providing significant cost savings.
Battery Type
Lithium-ion batteries are a very versatile power energy storage technology. They offer a variety of advantages over other battery types, including high power density, excellent charge efficiency and low self-discharge rates.
They are commonly found in mobile phones, digital cameras, laptops and portable medical devices. They also feature in a wide range of consumer electronics and household appliances, as well as a growing number of green energy applications such as electric vehicles and renewable energy storage systems.
The chemistry of lithium-ion batteries is based on the intercalation of Li ions in graphite electrodes. This allows for extremely high capacity per unit volume, compared to other rechargeable battery chemistries such as nickel-cadmium. The cell voltage of 3.6 volts is also an advantage over other common battery types, such as the three-cell AA nickel-cadmium pack used in most radios and video cameras.
Another benefit of Li-ion is that it is relatively maintenance free. Most packs use a Battery Management System (BMS) to ensure that all cells are at the same state of charge. This is accomplished through the use of transistor circuitry that can shut off the charging current and switch to constant voltage mode until balancing is complete. This helps to keep the battery from overcharging, which can reduce its lifespan. In addition, the BMS can prevent a single cell from overcharging or discharging faster than its fellow cells.
Battery Capacity
Lithium-ion battery packs use multiple lithium-ion cells to provide more energy and power than a single cell can offer on its own. These cells are connected to each other through porous separators that allow lithium ions to transport through during charging and discharging. Recent advances in electronic technology and modular design concepts have made Li-Ion battery systems safer, more robust, more flexible, and easier to charge and maintain than previous nickel-cadmium and nickel metal hydride chemistries. Packs incorporate a variety of protective circuitry including shutdown separators, UL 1642, and battery management systems.
The energy density of Lithium-ion batteries is significantly higher than other types of rechargeable batteries, allowing for greater capacity in a smaller package. This feature is crucial for applications such as electric vehicles and solar energy storage systems. In addition, lithium-ion batteries offer excellent charge efficiency and have an extremely long lifespan.
A rechargeable battery’s actual capacity is determined by measuring the number of charge cycles it can endure before its performance begins to degrade. To calculate the number of charge cycles a battery can tolerate, the manufacturer may perform tests on the battery under simulated use scenarios.
Lithium batteries can be used for a wide range of applications, from providing Li-ion battery pack back-up power in the event of a power interruption to running critical IT equipment in office environments or life-saving medical equipment. They also provide an efficient way to store solar energy for off-grid or hybrid solar systems.
Battery Weight
Lithium ion batteries offer the highest power density of any rechargeable battery chemistry while also being lightweight. As a result, they are the technology of choice for consumer electronics, toys, wireless headphones, handheld power tools, hybrid and electric vehicles, small appliances and electrical energy storage systems.
Li-ion batteries that have a total lithium content of 1.5 grams or more per cell and 8 grams or more in the battery pack are classified as class 9 miscellaneous hazardous material by the United Nations (UN). Special markings, shipping documents and handling precautions are required for international shipments containing these cells.
When used batteries or devices containing them are at the end of their service life, they are considered universal waste and must be managed in accordance with state hazardous waste regulations, as well as EPA requirements. Safe handling precautions include placing non-conductive tape over battery terminals and placing them in plastic bags.