ECJ EUROPEAN Cleaning Journal

Ann Laffeaty looks at the growing popularity of lithium ion batteries and asks manufacturers whether Li-ion is poised to become the battery of choice in the cleaning industry.

The battery landscape has changed dramatically over the past few decades. Most battery-operated cleaning machines used to be powered by flooded, AGM or gel products, all of which offer their own specific benefits. Flooded batteries are cheap and long-lasting while gel batteries are maintenance-free and spill-proof. And AGM batteries are low maintenance, require no watering and can be charged safely without the risk of emissions.

But then in the 1990s along came lithium ion. Mainly used in telecommunications equipment to begin with, lithium ion batteries are now powering everything from laptops to power tools and electric cars. And they are increasingly being used in cleaning machines as well where they offer numerous benefits over traditional models, according to Kärcher’s energy storage systems manager Jan Becker.

“These batteries require very little maintenance,” he said. “They also produce zero emissions, are low-noise and can be used indoors without any restrictions.”

Other advantages are a longer life cycle and a higher energy density, he adds. “The state-of-charge indicator is more reliable than with other types of battery as well which makes cleaning easier to control,” he said. “And the fact Li-ion machines offer faster charging capability and have a higher usage-to-charging ratio means the overall total cost of ownership is reduced.”

Li-ion batteries are used extensively in Kärcher’s compact floor cleaning machines and hand-held devices such as window vacs, high-pressure cleaners, vacuum cleaners and scrubber dryers such as the BR 35/12 and the BR 45/22.

According to Becker, the tide is definitely shifting towards the use of lithium ion in cleaning. “There are clear signs of a switch towards the use of Li-ion in cleaning machines wherever it is technically possible,” he said. “And customers are actively searching for Li-ion solutions as the advantages of these batteries become more widely understood.”

Higher investment

He concedes the initial investment required for lithium ion is higher than that of lead acid batteries. “However, the overall total cost of ownership with Li-ion is very attractive compared with lead acid,” he adds.

Kärcher uses a range of batteries in its cleaning machines including cylindrical and prismatic Li-ion cell and traditional lead acid products. “Our range of machines powered by Li-ion will be extended significantly in due course, but we will also keep lead acid in our portfolio due to the lower investment,” he said.

Diversey’s global portfolio manager for TASKI machines Stefan Wilms also claims lithium ion offers a number of advantages over traditional models. “In most cases our TASKI IntelliPower lithium ion batteries will last as long as the machine itself,” he said. “They can also withstand up to four times as many cycles as traditional models and the technology is particularly robust against interrupted charging sessions.”

According to Wilms, the company’s batteries are capable of fully charging a scrubber dryer in 90 minutes. “The same process can take anything from six to 10 hours with a non-lithium battery,” he claims.

Like Becker he says the relatively high initial cost of lithium ion is a key disadvantage. “However, lithium ion batteries don’t need to be replaced – and this is a significant benefit in terms of the full lifetime cost,” he says.

The difficulty in recycling the batteries can be a drawback, according to Wilms. “It is still a relatively new technology and many recycling facilities don’t yet have a way to recycle them sustainably,” he said. “However, we sense a change is on the way because recycling options in general are increasing month by month.”

Despite the advantages of lithium ion, he says traditional batteries remain a good option for price-sensitive customers and in situations where cleaning machines are only used periodically. “In these cases, traditional batteries will have an extended lifespan because they will be subject to fewer charging cycles and a lower level of wear,” he said.

The low weight of lithium ion is often quoted as an advantage, but he claims the increased weight of traditional batteries can actually be a benefit in some cases. “The heaviness of some machines – particularly walk-behind scrubber dryers - will generate brush pressure and enhance the cleaning performance with their own weight,” he said. Diversey’s lithium ion-powered machines that rely on weight-generated brush pressure use additional weights to compensate for the lighter battery, says Wilms.

Definite shift

Like other companies, Diversey has remarked a strong shift towards lithium ion. “In some cases it has been the enabler for the product itself,” said Wilms. “For example, the low weight and high energy density of lithium ion has allowed us to create cable-free offerings such as a backpack vacuum and an upright vacuum cleaner.”

He adds that the cost of lithium ion batteries has recently been reduced which has made them a more competitive option. Diversey uses TASKI IntelliPower batteries in several machines including
the AERO Up and AERO BP vacuum cleaners and the AERO 3500 ride-on sweeper vacuum.
IPC floorcare products manager Paolo Bassanini has also witnessed an increasing shift towards lithium ion.

“The long life of lithium ion batteries dramatically reduces the cost of battery replacement and maintenance,” he says. “The fact these batteries are considerably smaller and lighter than lead acid models also allows manufacturers to design more compact, ergonomic machines around smaller lithium packs. And they can be charged more quickly than lead acid while requiring less energy to do so, resulting in a significantly reduced environmental impact.”

Some disadvantages

However, he agrees with other commentators that there are disadvantages. “Lithium ion batteries require a protection circuit to keep the voltage and power levels within safe limits,” he says. “The fact they are subject to regulatory controls also means they are more expensive and difficult to ship. And the cost of traditional batteries is still considerably lower than that of lithium ion - and they are less risky to store.”

IPC uses a range of batteries in its machines including gel and AGM products. “However, lithium ion batteries are installed as a standard in our new compact CT5 scrubber dryer and are available as an option on our CT15 and CT30 scrubber dryer models,” said Bassanini.

He believes the relatively high cost of lithium ion and the transport difficulties the batteries represent will remain a barrier to their more widespread use. “This is despite the fact that lithium ion batteries are indisputably more productive and eco-friendly than traditional ones,” he adds.

Demand for lithium ion is growing in the cleaning sector, according to Battery Supplies’ export sales manager Micha Denys. “These batteries are lighter in weight than traditional models and have a longer lifespan,” he said. “They can also be charged more quickly and in any location since they are emission-free, which means no separate charging area is required. And intermediate charging – a practice that can be very harmful for lead acid batteries -  is perfectly possible with lithium ion.”

Battery Supplies offers LiFePO4, a lithium iron phosphate product which Denys claims to be 100 per cent safe. “There is no risk involved because we have developed our own battery management system which supervises the strings of LiFePO4 cells and monitors the balance between them and the temperature,” he said.

Batteries offered by the company include traditional lead acid, gel and lead carbon models. Introduced by Battery Supplies last year, lead carbon batteries are said to be a relatively new technology and involve the use of carbon in the negative plates.

“Lead carbon batteries cope better with intermediate charging than other traditional models and have almost twice the lifetime of a high quality gel battery,” said Denys. “They are currently very popular in the cleaning machine market.”

However like other commentators, he has remarked a growing demand for Li-ion. “The initial cost is still higher than that of open lead acid, gel or lead carbon batteries,” he said. “However, the price has decreased over the past five years and this has had a positive impact on demand. And the advantages of lithium ion show up very quickly when the battery is in use.”

But what effect – if any - has COVID-19 had on the lithium ion market?

Boosted demand

“The global pandemic has boosted demand for batteries in general,” says Denys. Diversey’s Stefan Wilms claims it has actually highlighted the advantages of lithium ion. “Site closures due to COVID-19 have meant that some cleaning machines remained out of use for months at a time,” he said.  “And when these sited reopened, it emerged that the sudden shutdown had led to the failure of the less robust traditional batteries used to power them.”

He added that lithium ion batteries had also proved their worth in environments where extra cleaning was taking place.

“For example, there has been a significantly higher use of cleaning machines and more wear and tear on the batteries in healthcare-related facilities,” he said. “In these situations lithium ion truly shines because it allows for the machine to be available 24/7.”