LFP lithium batteries: the right choice for material-handling equipment
Today’s market for industrial batteries has grown dramatically through innovation and the adoption of new technologies, such as multiple types of new-generation lithium batteries, hydrogen fuel cells, and new variations of the older lead-acid batteries. It is increasingly hard to make the right choice, given the variety of equipment types, makes, and models designed for a specific application and a specific work environment and operation pace.
The OneCharge engineering team zeroed in on lithium LFP cells as the best choice for industrial lithium batteries powering material-handling equipment and off-highway EVs (Class I, II, and III electric lift trucks; tugs; personnel and burden carriers; sweepers; scrubbers; and aerial platforms). We use LFP lithium cells in OneCharge batteries, which
- provide the best equipment performance;
- satisfy the requirements of high-power, demanding applications;
- exhibit the longest cycle life of a battery;
- ensure the top safety level of operation and reduce operation maintenance costs.
Lithium cells are named after the chemical composition of their cathode material
Cells are constructed of several elements, including the cathode, anode, electrolyte, and membrane. (To learn more, see the Lithium cell design page of this website.) The biggest impact on the specs of today’s commercially available batteries is made by the chemistry of their cathode materials. That is why battery cells are named after the chemical composition of the materials used in the cathode of a lithium cell.
There are multiple cathode materials to choose from within the Li-ion technology space. The best-known active component of the cathode is cobalt, widely used in batteries for electronics and EVs. Today, battery manufacturers using cobalt are facing serious supply-chain sustainability issues (like unethical mining practices, including the use of child labor). Cobalt is frequently substituted out with iron (LFP), nickel, manganese, and aluminum.
OneCharge batteries are based on LFP cells, the optimal choice for material-handling applications.
Why LFP is the best choice for material handling operations
As stated above, LFP chemistry is the optimal choice for material handling equipment batteries, and here’s why.
Of all the various types of lithium-ion batteries, three cell chemistry types emerge as widely used in on- and off-highway electric vehicles: lithium ferrophosphate, or lithium iron phosphate (LFP), lithium nickel manganese cobalt oxide (NMC), and lithium nickel cobalt aluminum oxide (NCA).
All batteries degrade with usage, decreasing their Ah capacity with each charge/discharge cycle. In material handling, batteries usually become unusable when they drop below 80% of their nominal capacity.
A battery’s longevity, or its cycle life, depends on three main factors:
- chemical composition of cathode materials;
- ambient temperature of operation;
- depth of discharge.
The graph below shows the results of recent independent degradation tests of the three types of cells with different chemistry, under equal conditions of temperature and depth of discharge.
One “equivalent full cycle” is the sum of charge/discharge events that add up to one full (zero to 100%) charge and one full (to zero) discharge of a battery.
LFP lithium batteries exhibit superior performance compared to NMC—they offer a longer lifespan and are generally less expensive.
Lithium nickel cobalt aluminum oxide (NCA) batteries performed similarly to or worse than NMC.
The tests were performed at Sandia National Laboratories as “part of a broader effort to determine and characterize the safety and reliability of commercial Li-ion cells.”
Apart from longer cycle life, LFP wins on safety, with better stability and a higher thermal run-away temperature threshold (roughly 420°F for NMC and 520°F for LFP).
NMC chemistry is higher on specific energy, which means NMC cells have higher energy density than LFP. This is important for electronics and electric vehicles, where battery weight is a decisive factor (the lighter the better). On the other hand, industrial batteries for material handling applications are often engineered as a counter-weight (the heavier the better).
Main characteristics of lithium cell chemistry types
Battery cells are mainly defined by the following:
- specific energy (how much energy a system contains in comparison to its mass; typically expressed in watt-hours per kilogram, Wh/kg);
- specific power (the amount of power in a given mass; typically expressed in watts per kilogram, W/kg);
- cost (influenced by the rarity and cost of raw materials, and by technological complexity);
- safety (risk factors, like temperature threshold for thermal runaway);
- lifespan (the number of cycles leading to critically low decrease of capacity, usually 80% in material handling applications);
- performance (capacity, voltage and resistance).
Here are the three types in detail.
Lithium Ferrophosphate (LFP)
LFP is a popular, cost-effective cathode material for lithium-ion cells that are known to deliver excellent safety and long life span, which makes it particularly well-suited for specialty battery applications requiring high load currents and endurance.
An LFP cathode offers several key advantages, including a high current rating, long cycle life, and superior thermal stability, which makes it one of the safest and most abuse-tolerant cathode material options. LFP delivers a lower nominal voltage, which results in lower specific energy than other cathode materials. LFP batteries tend to have a somewhat higher self-discharge than other Li-ion battery types.
- Excellent charge and discharge rate capability
- Superior low-temperature performance
- Stable resistance
- Stable voltage drop under life cycle testing in high-temperature environments
Lithium Nickel Manganese Cobalt Oxide (NMC)
One of the most widely used Li-ion cathodes is obtained by combining nickel, manganese, and cobalt. Lithium nickel manganese cobalt oxide (LiNiMnCoO2), or NMC, has become the go-to cathode material to develop batteries for power tools, e-bikes, and other electric powertrains. It delivers strong overall performance, high specific energy, and a low self-heating rate. This cathode power is used for EV batteries (Tesla? Yes, they are currently using both NMC and NCA, but recently started to switch to LFP).
The NMC formula typically consists of 33% nickel, 33% manganese, and 33% cobalt. This blend, sometimes referred to as 1-1-1, is a popular option for mass-produced cells in applications requiring frequent cycling (automotive, electronics) due to the reduced material cost with a lower cobalt content.
Lithium Nickel Cobalt Aluminum Oxide (NCA)
A lithium nickel cobalt aluminum oxide, or NCA, battery shares similarities with the NMC by offering high specific energy, reasonably good specific power, and a relatively long life span, making NCA a candidate for EV powertrains. The main downsides are safety and cost, as well as the recent supply chain issues.
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