9314451122 info@duak.in
ABOUT LITHIUM

Lithium iron phosphate (LFP) and lithium nickel manganese cobalt (NMC) are both members of the lithium-ion battery family. Lithium is a lightweight metal used to make small high-capacity batteries. Lithium is a soft, white, alkali metal. In its pure form, lithium is flammable and reactive. In nature, it is found within minerals like quartz, ocean water, and mica. Lithium has many uses. Manufacturers use it to create flame-retardant ceramics, used to make some of the best-performing batteries. 

There are many different kinds of lithium-ion batteries but they all follow a similar structure. The main difference between them all is what metals are used to make the cathode side of the battery. This affects the cost, life, and performance greatly. Some of the metals used in cathode, such as cobalt; cost even more than the raw lithium, and this is why you might see such large variations in battery pricing. Below, we will discuss the difference between two of the newer and more popular lithium batteries.

What exactly are batteries and lithium-ion batteries?

Batteries are made of four main parts

Anode (electrode)

Cathode (electrode)

Electrolyte and/or Separator (lithium salts/metals)

 

 

The separator, as you may have guessed, separates the negative anode from the positive cathode. This separator is where the electrolyte lays also, passing ion charges from one side of the battery to the other.

When a battery is charging, lithium ions travel from the positive cathode to the negative anode. During the discharge, ions flow from the anode to the cathode. The electrolyte is a medium that helps the ions flow freely from one electrode (cathode) to the other while the separator blocks electrons from traveling freely through the device.

As mentioned above, the thing that really makes these batteries different, and all batteries – for that matter – different is the type of metals used to make the cathode. In lithium batteries, the cathode can be made from varying amounts of metals like nickel, carbon, and manganese. The differing amounts of metals used will drastically change the way each battery performs.

lithium-cell-structure

Lithium Nickel Manganese Cobalt Oxide (LiNiMnCoO2) — NMC

One of the most successful Li-ion systems is a cathode combination of nickel-manganese-cobalt (NMC). Similar to Li-manganese, these systems can be tailored to serve as Energy Cell or Power Cell. For example, NMC in an 18650 cell for moderate load condition has a capacity of about 2,800mAh and can deliver 4A to 5A; NMC in the same cell optimized for specific power has a capacity of only about 2,000mAh but delivers a continuous discharge current of 20A. A silicon-based anode will go to 4,000mAh and higher but at reduced loading capability and shorter cycle life. Silicon added to graphite has the drawback that the anode grows and shrinks with charge and discharge, making the cell mechanically unstable                        .

NMC is the battery of choice for power tools, e-bikes and other electric powertrains. The cathode combination is typically one-third nickel, one-third manganese and one-third cobalt, also known as 1-1-1. This offers a unique blend that also lowers the raw material cost due to reduced cobalt content. Another successful combination is NCM with 5 parts nickel, 3 parts cobalt and 2 parts manganese (5-3-2). Other combinations using various amounts of cathode materials are possible                                    

Battery manufacturers move away from cobalt systems toward nickel cathodes because of the high cost of cobalt. Nickel-based systems have higher energy density, lower cost, and longer cycle life than the cobalt-based cells but they have a slightly lower voltage            .

New electrolytes and additives enable charging to 4.4V/cell and higher to boost capacity.NMC has good overall performance and excels on specific energy. This battery is the preferred candidate for the electric vehicle and has the lowest self-heating   

Lithium nickel manganese cobalt oxide batteries have a multi-layered cathode made of nickel, cobalt, and manganese. Scientists realized that each of these metals has favorable qualities, but their shortcomings leave much to be desired. When combined, all three of these metals produce a cathode with great specific energy and power. The lifespan of lithium nickel manganese cobalt oxide batteries is also very long – long enough for these batteries to power vehicles like Tesla’s. They’re also used in medical devices and industrial equipment. Thermal stability for lithium nickel manganese cobalt oxide batteries is moderate. The thermal runaway is over 300 degrees Fahrenheit.

Voltages
3.60V, 3.70V nominal; typical operating range 3.0–4.2V/cell, or higher
Specific energy (capacity)
150–220Wh/kg
Charge (C-rate)
0.7–1C, charges to 4.20V, some go to 4.30V; 3h charge typical. Charge current above 1C shortens battery life.
Discharge (C-rate)
1C; 2C possible on some cells; 2.50V cut-off
Cycle life
1000–2000 (related to depth of discharge, temperature)
Thermal runaway
210°C (410°F) typical. High charge promotes thermal runa-way
Applications
E-bikes, medical devices, EVs, industrial

Lithium Iron Phosphate(LiFePO4) — LFP

Li-phosphate is more tolerant to full charge conditions and is less stressed than other lithium-ion systems if kept at high voltage for a prolonged time. As a trade-off, its lower nominal voltage of 3.2V/cell reduces the specific energy below that of cobalt-blended lithium-ion. With most batteries, cold temperature reduces performance and elevated storage temperature shortens the service life, and Li-phosphate is no exception. Li-phosphate has a higher self-discharge than other Li-ion batteries, which can cause balancing issues with aging. This can be mitigated by buying high quality cells and/or using sophisticated control electronics, both of which increase the cost of the pack. Cleanliness in manufacturing is of importance for longevity. There is no tolerance for moisture, lest the battery will only deliver 50 cycles.

Li-phosphate is often used to replace the lead acid starter battery. Four cells in series produce 12.8V, a similar voltage to six 2V lead acid cells in series. Vehicles charge lead acid to 14.40V (2.40V/cell) and maintain a topping charge. Topping charge is applied to maintain full charge level and prevent sulfation on lead acid batteries.

With four Li-phosphate cells in series, each cell tops at 3.60V, which is the correct full-charge voltage. At this point, the charge should be disconnected but the topping charge continues while driving. Li-phosphate is tolerant to some overcharge; however, keeping the voltage at 14.40V for a prolonged time, as most vehicles do on a long road trip, could stress Li-phosphate. Time will tell how durable Li-Phosphate will be as a lead acid replacement with a regular vehicle charging system. Cold temperature also reduces performance of Li-ion and this could affect the cranking ability in extreme cases.

Lithium iron phosphate is a range of lithium-ion batteries that use phosphate as cathode material. Lithium-iron phosphate batteries possess some attractive qualities. They have a long cycle life which is great for devices that need to be powered for many years, specifically 10 years and beyond. over the last few years, several solar battery backup companies selling LFP batteries have emerged. They are a solid option, but they also have limitations. these batteries can also withstand high-voltage use for an extended period of time. Withstanding high voltage goes hand in hand with thermal stability. Batteries with low thermal stability are prone to electric shortages that lead to explosions and fires.

Voltages
3.20, 3.30V nominal; typical operating range 2.5–3.65V/cell
Specific energy (capacity)
90–120Wh/kg
Charge (C-rate)
1C typical, charges to 3.65V; 3h charge time typical
Discharge (C-rate)
1C, 25C on some cells; 40A pulse (2s); 2.50V cut-off (lower that 2V causes damage)
Cycle life
2000 and higher (related to depth of discharge, temperature)
Thermal runaway
270°C (518°F) Very safe battery even if fully charged
Cost
~$580 per kWh (Source: RWTH, Aachen)
Applications
Portable and stationary needing high load currents and endurance

CONTACT

C-182, Rd Number 9F, Vishwakarma Industrial Area, Jaipur, Rajasthan, 302013

9314451122
0141-4112624

info@duak.in

NEWSLETTER

Subscribe to our newsletter to
receive weeky news, updates
and special offers.

Get Social