As more electric trucks, SUVs and sports cars are introduced to the market, the size and quantity of battery packs required to power them continue to grow.
To achieve a power output of 170 kWh to 215 kWh, battery packs typically contain over 1,000 individual cells, some of which, but not all, are grouped into dozens of modules. To put this into perspective, the largest commercial battery packs for these vehicles are comparable in size to a king-sized mattress and can weigh nearly 2,000 pounds.
Large battery packs of this scale pose considerable challenges when attempting to recover valuable materials during recycling, starting with the difficulties of lifting and integrating them into conventional battery recycling systems.
When this happens, recyclers are required to break down large packs into smaller components. However, this process is highly challenging because potting materials secure the components into a solid structure. This makes it difficult to cut, dissolve or separate the pack into parts 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. Simply put, managing the immense heat and energy that can be released during recycling presents considerable technical challenges that must be addressed.
Fortunately, a battery recycling equipment manufacturer in the U.S. now provides systems capable of handling large battery packs without requiring disassembly or discharge. These systems, which are designed to seamlessly integrate as the “front end” of existing recycling processes, are already in use by the largest EV manufacturers in the world. Systems are now in production in Germany, the UK and the U.S.
“Battery recyclers require a comprehensive, turnkey solution designed to safely and efficiently shred the largest commercial EV battery packs on the market, without having to discharge the battery first,” said John Neuens, industrial consultant for Milwaukee, WI-based LithiBatt, a division of BCA Industries, an OEM of closed loop recycling systems for Li-ion, LiFePO4, nickel metal hydride, zinc-bromine and other types of batteries.
These large battery pack systems enable EV manufacturers and major recyclers to efficiently and safely recover valuable ferrous metals and battery-grade black mass, with a complex mix of metals such as lithium, cobalt, nickel and manganese that can be refined into precursor cathode active material (pCAM) through hydrometallurgical processes by the recycler themselves or third-party buyers of black mass.
An advanced large battery pack recycling system like that from BCA Industries features fully variable and automated speed control based on the hydraulic load.BCA Industries
Overcoming Challenges
Safe shredding of large battery packs comes with considerable safety and processing challenges. Through extensive research, design and production testing, LithiBatt engineered a fully sealed system incorporating a water-nitrogen blanket, lift-and-dump mechanism, three-part progressive shredding, air and water treatment system along with other unique design features.
“The hydro-nitrogen ‘large pack’ battery recycling systems can safely process anything from multiple smaller packs and modules to whole battery packs used in electric trucks and SUVs,” said Neuens, adding that the system is used by the largest EV manufacturer in America, as well as some of the world’s largest recyclers to shred packs that measure 70”x118”x15” and weigh over 1,700 pounds.
Neuens details the challenges and demonstrates how LithiBatt’s advanced design process is successfully addressing them.
Watertight, Airlocked
LithiBatt’s large-scale Li-ion reduction system employs water and a nitrogen “blanket” to regulate thermal activity.
Throughout the entire shredding process, EV battery packs are kept submerged to suppress or significantly reduce energy release with most of the VOC’s remaining in the water solution.
An inert nitrogen environment stops thermal runaway by substantially reducing the available oxygen concentration, which is crucial for combustion and the propagation of a fire within a battery experiencing thermal runaway. This can effectively “smother” the reaction and prevent it from escalating further.
“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. Combined with nitrogen, we can control and eliminate thermal events with a wet process. Pouch style batteries have water absorbent materials but that can be processed in our system design. This method also speeds battery processing over a dry system, with all of its safety and air quality problems,” said Neuens.
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 lies in the fact that shredders are typically not designed to be fully submerged in water and are not built to be watertight. Specialized 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, a highly unique design configuration.
Besides being watertight, the system also required airlocks to ensure the preservation of specific environmental conditions and the retention of nitrogen. According to Neuens, LithiBatt designed and manufactured the airlock system themselves because the market lacked a suitably large, affordable option.
Large battery pack systems enable EV manufacturers and major recyclers to efficiently and safely recover valuable ferrous metals and battery-grade black mass that can then be refined by the recycler or third-party buyers.BCA Industries
Lift and Dump Loading
Whole charged packs up to up to 72 inches (6 feet) wide and 3,000-pounds are fed into the submerged primary shredder using a hydraulic dumper lift. The lift is designed to seal against the surface of the first chamber, open a tailgate and slide the battery pack into the primary shredder. The lift and dump mechanism is nonconductive since moving an EV battery over metal rollers can cause an electrical-thermal reaction.
Three-Stage Progressive Shredding
Breaking down large battery packs involves a three-step shredding process, which reduces individual battery cells to 5/8-inch discharged material while safely dispersing the stored energy into the system without an effluent. This gradual shredding method ensures that all of the battery cells are fully and effectively cut.
In primary shredding, processing dense, heavy ferrous metals requires the use of larger, more durable knives. Thin knives are prone to deflection under the density of these materials, which can lead to blades rubbing against each other, ultimately causing damage or dulling the knife system.
Following the initial shredding process, EV battery materials are transferred to secondary and tertiary shredders equipped with airlocks and specially designed water-filled augers.
At a further secondary stage available, progressively thinner Triplus knives are used to achieve the specified final material output and separation of metals, plastics and remnant 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.
Neuens emphasizes that the system can recycle smaller packs or modules as well.
Throughput is maximized because the shredding system can adjust to the demands of each load. This is accomplished using variable displacement hydraulics that can run between 9 and 28 RPM, changing quickly based on the hydraulic load.
“Most battery shredders operate at a single fixed speed, with a few offering two-speed options,” explained Neuens. “This BCA Model 2000 features fully variable and automated speed control based on the hydraulic load. It can process smaller batteries at a higher RPM and slow down when encountering harder, denser materials. When it reaches less dense or harder-to-shred materials, it automatically adjusts to a faster speed in fractions of a second without a mechanical wear factor.”
A knife technology like that from BCA Industries is specifically designed for wet battery recycling, ensuring materials are reduced to a consistent and uniform size in a single pass.BCA Industries
Valuable Material Recovery
LithiBatt’s large pack Li-ion reduction system takes entire EV packs to shippable, manageable 5/8-inch inert material, separating out black mass and with a secondary system offered, separates ferrous materials as well as non-ferrous metals such as copper and aluminum.
According to Neuens, the large battery pack reduction system can recover approximately 60% of the black mass, which is considered valuable due to high demand for lithium, cobalt and nickel to manufacture new batteries. However, the additional secondary equipment can be incorporated to achieve a black mass separation rate of up to 95%.
According to Neuens, a closed wet battery recycling system can capture black mass more effectively and at far improved purity if properly designed and built by companies experienced with these techniques.
“All the other particles besides the black mass are very large, so it is relatively easy to filter and press out, dewater and dry. The result is very clean, sellable black mass.
For industry professionals that need to safely and efficiently reclaim valuable materials from even the largest EV battery packs to increase profitability, adding a modular large pack Li-ion reduction system to their existing process will likely become the best practice.