The final price of lithium batteries is still high compared with lead batteries. The price of the rare metals they are made of - lithium, cobalt and nickel - is sky-high.

New energy conservation technologies may be appearing regularly, but lead batteries still have a huge market share.

So why not recycle lithium batteries?

Colossal demand

Lithium batteries are everywhere: smartphones, connected watches, off-grid car systems, transport, marine applications, etc.

The main lithium producers are Australia (42,000 tonnes) in 2020, followed by Chile (18,000 tonnes), China (14,000 tonnes), Argentina (6,200 tonnes) and Europe with... 0 tonnes.

Demand for this chemical is growing at a stratospheric rate. Specialists expect a 40-fold increase by 2040.

The problem is that natural resources are not up to the task. The price of lithium ore increased fivefold in 2022.

To make matters worse, the term lithium battery covers accumulators of different chemistries: there are lithium-metal-polymer (LMP), lithium-polymer (Li-Po) and lithium-cobalt (LCO) batteries, nickel-manganese-cobalt (NMC), lithium-manganese (LMO), lithium-iron-phosphate (LFP/LiFePO4), or nickel-cobalt-aluminium (NCA) batteries, each using a number of other more or less rare ores. ..

These ores play a large part in the equation, as less than 2% of lithium is used in these batteries. A BMW I3 battery, for example, contains less than 5 kg of lithium for a total of 230 kg.

A substantial price difference

It's no secret that the price of batteries based on lithium cells is much higher than that of lead batteries. Worldwide, on a per metric tonne basis, lithium technologies cost 7 times more than lead.

Even allowing for the fact that lithium batteries have almost 50% more usable capacity than lead batteries, the price difference factor remains high, at between 3 and 4 in favour of lead.

In January 2022, a tonne of lithium will cost more than €45,000, while a tonne of lead will rarely cost more than €2,500.

Lessons to be learned from lead 

More than 2 billion tonnes of lead were used to manufacture lead-acid batteries in 2020, compared with less than 90 million tonnes of lithium.

Where does this disparity come from? Lead-acid technology has been declared obsolete and moribund for a decade, yet it remains in the majority, mainly because of its cost.

This is because lead-acid batteries can be easily recycled, even at such a low price. We've all seen the example: whether it's a boat or a car, when you buy new batteries, the supplier is happy to take them back.

Over 99% of the world's lead-acid batteries end up being recycled, compared with just 1% of their lithium counterparts.

Battery recycling

Recovering the lead contained in lead-acid batteries presents no great difficulty. Once emptied and stripped of their cases, the plates are easily accessible. Recycling is easily automated and yields are high.

Lead smelting requires little energy, and the life cycle of batteries using this technology is remarkably circular.

Lithium batteries, on the other hand, have a much more complex life cycle, with a range of interesting components that are difficult to recycle.

Pyrometallurgy

This recycling technique involves melting down used batteries. It produces alloys and ashes containing the lithium. It consumes a lot of energy and requires a second treatment to purify the metals recovered. All types of lithium batteries can be treated, but the cost/benefit ratio is not attractive.

Hydrometallurgy

Here, the cells are broken down by chemical treatment. This requires a fine chemistry, dosed for each type of chemistry and type of cell, dosages that limit the development of this recycling method in conventional "off-the-shelf" recycling channels.

Direct recycling

The hope lies in the deconstruction of these objects. A method consisting of opening up the cell assemblies, separating them to separate out the components and making virtually pure metals available for recycling.

The major difficulty lay in the great heterogeneity of lithium cells, ranging from that of an AAA battery to a block weighing several tens of kilograms.

Automation of the dismantling process should enable us to adapt to each model of chemistry, type and discarded cell.

American Battery Technology Company (ABTC), a company founded and run by a former Tesla executive responsible for battery design, is a pioneer in this field. ABTC carries out a study of the manufacturing process for a given type of battery and imagines deconstruction right down to the cell stage, before processing the cells using hydrometallurgy.

This method greatly limits the type of cells to be processed and opens the way to partnerships with electric vehicle manufacturers. 

The widespread use of these recycling processes is one of the major challenges facing the lithium industry.