The economics of reusing batteries from plug-in vehicles for residential energy storage systems (ESS) doesn’t make sense, at least according to technology analysts Lux Research.
Lux came to the conclusion after comparing a residential 11.2kWh ESS system using second-life batteries at around $4,600 against a new 7kWh system, at $6,000.
Lux said the two have the same amount of usable energy due to depth of discharge cycling— 50% and 80% respectively.
New systems from US firm Tesla costs around $5,000 (lease) for its 10kWh Powerwall and German firm Sonnen’s 4kWh sonnenBatterie costs around $6,000 (before installation).
Almost every vehicle manufacturer worth its salt has dipped a toe into the ESS market as they try to find a way of re-using ‘old’ lithium-ion electric vehicle packs.
Reuse is an obvious solution because a battery pack is estimated to have around 80% of its original capacity left when it reaches its ‘end of life’.
But Christopher Robinson, Lux Research Associate and lead author of the report, said he didn’t expect the economics of recycling over reusing to change in the next 15 years.
He said: “The main reason is that second-use batteries are only appropriate in applications which don’t require daily cycling. They are more suitable for shallow depth-of-discharge or infrequent cycling scenarios, limiting the number of markets that batteries can be sold into.
“Another part of the recycle Vs. reuse equation that many don’t think about is the processing of used batteries, which must occur before they can be used in other applications. The battery pack must be disassembled, which is currently done manually, and each of the cells needs to be tested for remaining capacity.
“The cells are then sorted into groups of similar capacity before being integrated into another system. With the drastic cost reductions coming from GWh-scale factories, and considering the lower performance and added processing costs for used cells, recycling used cells for materials to make new ones looks like a better value proposition.”
As a caveat, he added that innovations in areas like packaging and testing could tip the balance in the future, “so companies should have plans for both recycling and reuse”.
Robinson’s findings were in a report titled “Reuse or Recycle: The Billion-dollar Battery Question“.
It might be some way off, according to Robinson, but the industry and governments are waking up to the need for a workable recycling system.
This week in Michigan, US, NAATBatt is holding a recycling workshop, and in Australia the government is circulating a paper about how to recycle lithium-ion.
In Belgium, recycling firm Umicore has a facility capable of recycling 7,000 MT of lithium-ion batteries, around 35,000 EVs per year. For scale, in the first half of 2016, 91,000 EVs were sold in Europe.
Recycling processes
Current recycling technologies include pyrometallurgical processing, or smelting, mechanical processing to recover cathode materials directly, and hydrometallurgical processing.
Minerals firm American Manganese (AMI) has recently filed its provisional patent application for a hydrometallurgical process with the US Patent and Trademark Office.
The company claims its process can recover lithium, cobalt, nickel, aluminium and manganese from spent lithium-ion EV batteries following a proof of concept program by Kemetco Research.
Larry Reaugh, president and chief executive officer of AMI said the recycling process could provide a verifiable source of cathode material feedstock.
He added: “As the adoption of electric vehicles accelerates, the problems of supplying new cathode materials for new EV lithium-ion batteries and disposing of spent lithium ion EV batteries will escalate accordingly.
“AMI’s recycling process could provide a secure source, thereby reducing the need for new mines in potentially economically or socially risky jurisdictions.”
Kemetco demonstrated leach extractions of 100% were possible for lithium and cobalt from cathode powders used for lithium-ion batteries.
High purity cathode compounds were combined and heat-treated to regenerate cathode materials, which were then used to build a working lithium-ion coin cell battery.
