Lithium batteries unlock efficiency and performance improvements across multiple industries, paving the way for original equipment manufacturers (OEMs) to enhance their floor care machines.
That said, not all lithium chemistries are created equal. They vary significantly in crucial areas like capacity, power output, and safety—factors that directly impact floor care machines’ operational demands.
While the transition to lithium batteries guarantees performance upgrades, OEMs must identify the most suitable lithium chemistry for their specific products to optimize their offerings and maintain a competitive edge in the market.
Different Lithium Battery Chemistries
The lithium batteries widely used today in various commercial applications rely on one of six proven effective and safe chemistries. However, the variations between these chemistries make them better suited for specific applications and operational environments.
The primary difference between them is the cathode material used:
- Lithium Cobalt Oxide (LiCoO2) – Also known as LCO, this chemistry is characterized by high energy storage capacity, but its use is somewhat restricted due to having the lowest thermal runaway threshold alongside NCA (150oC). As a result, they’re typically used in products requiring long cycles in low-stress conditions, like mobile phones, tablets, and laptops.
- Lithium Manganese Oxide (LiMn2O4) – Also known as LMO, this chemistry is characterized by strong performance across most crucial metrics except lifespan. Because of the ability to quickly charge and discharge, they’re often used in applications requiring significant amounts of immediate power output (e.g., power tools, medical devices, and some electric power trains).
- Lithium Nickel Manganese Cobalt Oxide (LiNiMnCoO2) – Also known as NMC, this chemistry is characterized by a well-rounded performance. It’s achieved by blending nickel, manganese, and cobalt to compensate for their individual characteristics and provide electric power trains with a reliable energy source. The chemistry’s ratio can be adjusted to better suit certain applications.
- Lithium Iron Phosphate (LiFePO4) – Also known as LFP, this chemistry is characterized by a well-rounded performance—particularly high power output levels, long life spans, and better resilience against deep discharging. This makes LFP batteries especially suited for motive applications like floor care machines or electric vehicles.
- Lithium Nickel Cobalt Aluminum Oxide (LiNiCoAlO2) – Also known as NCA, this chemistry’s characteristics resemble NMC batteries, with some trade-off between greater power output against a shorter lifespan and lower thermal runaway threshold. The greater risk of “thermal runaway” and overheating than with NMC batteries comes from the higher nickel content.
- Lithium Titanate (Li4Ti5O12) – Also known as LTO, this chemistry has a long life span, extremely rapid discharging and charging, and superior low-temperature performance. However, the cost of this battery chemistry may be prohibitive, so applications generally keep to some electric power trains and uninterrupted power supplies (UPS).
Optimal Lithium Battery Chemistries for Motive Applications
Due to their characteristics, the most widely used lithium cell types in motive power applications are NMC, LFP, and NCA chemistries. This is because they achieve the best balance across power output, lifespan, and cost when meeting the operational demands of floor care.
Most OEMs will choose from these three options based on their other characteristics and the needs of a given machine.
LFP—Lithium Iron Phosphate (LiFePO4)
Given the combination of high power output, long life spans (commonly 3,000-5,000 cycles), durability, and reliable safety, LFP likely comprises the most commonly used lithium cell type for floor care machines.
They provide strong performance across these crucial metrics. This includes being:
- The safest chemistry type (as there is little to no risk of thermal runaway)
- Nontoxic and easily recycled
- Capable of safe 100% discharge
- Significantly more affordable.
The one drawback to LFPs is that they traditionally provide less energy density, which can increase the weight and amount of on-board space the battery requires to achieve a similar cycle length. Still, compared to a lead-acid battery, LFPs are roughly 70% lighter. And recent advancements in LFP density are helping overcome the density challenge—potentially positioning them as the go-to chemistry for EV applications.
NMC—Lithium Nickel Manganese Cobalt Oxide (LiNiMnCoO2)
If power density remains a concern, OEMs may choose NMC batteries for their floor care machines. They’re extremely well balanced across power output, life span, and safety performance characteristics. Most importantly, the energy densities and power output have made them a preferred option of EV manufacturers looking to maximize range.
If the machine is expected to see long duty cycles (e.g., large area floors, minimal opportunity charging), NMC may be a better choice over LFP despite the added cost.
One of the optimal chemistry blends for this battery is a 1:1:1 ratio of nickel, manganese, and cobalt because of the balance it achieves:
- Nickel – High specific energy but low stability
- Manganese – Low internal resistance but low specific energy
- Cobalt – High energy density and lifespan
However, the rarity (and resulting cost) of cobalt has also led to different ratios being tried.
For example, OEMs might consider:
- NCM532 – 5 parts nickel : 3 parts cobalt : 2 parts manganese
- NMC622 – 6 parts nickel : 2 parts cobalt : 2 parts manganese
- NMC811 – 8 parts nickel : 1 part cobalt : 1 part manganese
The primary drawbacks of NMC batteries are their shorter lifespan (1,000-2,000 charges) and cost compared to LFP options.
NCA—Lithium Cobalt Aluminum Oxide (LiNiCoAlO2)
NCA cells are quite similar to NMC, offering increased energy density. However, the trade-off for this additional energy density is:
- Shorter life spans (500 cycles)
- Lower thermal runaway threshold
- More expensive
As a result, NCA chemistries should primarily be used for machines where energy density and storage capacity are the paramount consideration for normal use.
Choosing the Best Lithium Chemistry for Your Machines
Overall, transitioning to lithium batteries will likely be easier for floor care OEMs than in other industries. This is because the operational requirements for floor care equipment are already incentivized using absorbed glass mat (AGM) or sealed lead-acid (SLA) batteries over flooded lead-acid batteries for robust, sealed, and lower-maintenance energy storage.
However, lithium still likely results in a lower total cost of ownership (TCO) for floor care companies. Maintenance costs, life cycle, and the ability to opportunity charge with less detrimental effects all favor lithium power storage.
Floor care machine designers should evaluate the design requirements of their machines alongside battery and charging partners to assess each lithium cell type’s strengths against those specific requirements. The energy requirements of one machine may define its storage capacity and favor one cell type. Life span concerns on another machine may suggest a different chemistry. Finally, extreme safety requirements may be the most pressing concern.