US battery tech pioneer recovers 95% black mass

US firm LithiBatt has created an innovative shredding solution to deliver end-of-life treatment for the growing number of larger electric vehicles entering the automotive market.

To achieve a power output of 170 kWh to 215 kWh, battery packs typically contain more than 1 000 individual cells, often grouped into dozens of modules. ‘The largest commercial battery packs for electric vehicles are as big as a king-sized mattress and can weigh over 900kg,’ according to LithiBatt.

No discharge or disassembly

The company, based in Milwaukee, observes that recyclers are required to break down large packs into smaller components. However, it is difficult to cut, dissolve or separate the pack without causing damage.

‘Attempts to do so risk puncturing or harming the cells, potentially leading to fire or even thermal runaways that cannot be extinguished. Just the act of shredding batteries that haven’t been fully discharged can introduce joules of energy into the system.’

LithiBatt products are designed to integrate at the front end of existing  processes to handle large battery packs without disassembly or discharge.

Hydro-nitrogen power

The innovative systems are already up and running at leading EV manufacturers. Systems are now in production in Germany, the UK and the US.

Through extensive research, design, and production testing, LithiBatt engineered a sealed system incorporating a water-nitrogen blanket, lift-and-dump mechanics, three-part progressive shredding, and an air and water treatment system along with other unique design features.

The large-scale Li-ion reduction system regulates thermal activity throughout the shredding process. EV battery packs are kept submerged to suppress or significantly reduce energy release with most of the volatile organic compounds remaining in the water solution.

An inert nitrogen environment stops thermal runaway by substantially reducing the available oxygen concentration. This can effectively smother the reaction and prevent it from escalating.

Watertight

‘Since the recyclable Li-ion battery black mass material does not readily absorb water, it can be used to cool the materials and extinguish the fires,’ says LithBatt engineer John Neuens. ‘Combined with nitrogen, we can control and eliminate thermal events with a wet process.

‘Pouch-style batteries have water absorbent materials that can be processed in our system. This method also speeds battery processing over a dry system, with all of its safety and air quality problems.’

To achieve this, LithiBatt created a system that is both water- and airtight to manage lithium batteries of this size, density, and energy output.

Neuens explains that the challenge is that shredders are typically not designed to be fully submerged in water and are not built to be watertight. Specialised seals and stainless-steel chamber liners were installed in the primary shredder to allow for complete submersion of the batteries or a robust spray system.

Three-stage shredding

Breaking down large battery packs involves a three-step process which reduces individual battery cells to 12-20cm discharged material while safely dispersing the stored energy into the system without an effluent. This gradual shredding method ensures that the battery cells are fully and effectively cut.

Following the initial shredding process, EV materials are transferred to secondary and tertiary shredders equipped with airlocks and specially designed water-filled augers.

Next, progressively thinner Triplus knives may be used to achieve the specified final material output and separation of metals, plastics and black mass. This patented knife technology is specifically designed for wet battery recycling, ensuring materials are reduced to a consistent and uniform size in a single pass without the need for screening, eliminating concerns about clogging.

Throughput is maximised because the shredding system can be adjusted per load.

Up to 95% black mass

LithiBatt’s solution separates black, ferrous materials as well as non-ferrous metals such as copper and aluminum. According to Neuens, the system typically recovers around 60% of the black mass. However, additional equipment can be incorporated to achieve a separation rate of up to 95%.

‘All the other particles besides the black mass are very large, so it is relatively easy to filter and press out, dewater, and dry,’ Neuens says. ‘The result is very clean, sellable black mass.’