When an electric vehicle (EV) comes off the road, what happens to its battery? Lithium-ion batteries are an important part of electric vehicle batteries, which manufacturers, policy makers, and EV owners must address. It is estimated that EVs make up a small percentage of the automotive market today. Several options for reuse and recycling are being evaluated using the batteries coming off the road.
Rather than recycling batteries to recover energy materials, reusing batteries in secondary applications may be a more effective approach.
It may be possible to reduce upfront battery costs of electric cars by reusing, or recycling, the batteries, as well as increase the value of used electric cars.
In light of the growing market for electric vehicles, second-life batteries could also provide utility and electricity consumers with low-cost storage options. The policy system needs to reduce barriers and ensure ethical, sustainable, and responsible practices in order to enable widespread EV battery reuse.
The market for second-life batteries
Second-life batteries will be in high demand as the market for electric vehicles continues to grow. Academic studies and industry reports indicate that by 2030 there will be a global supply of second-life batteries of 112-275 GWh per year. The total energy storage installed in the US in 2018 was 780 MWh, which is over 200 times the total energy storage installed in 2018.
EVs are the top-selling vehicles in California, and it’s estimated that by 2027, 45,000 EV batteries in the state will have reached their end of life, resulting in over a GWh/year of renewable energy storage.
Why EV batteries could be reused
It is likely that used EV batteries will have more than two thirds of their usable energy storage left after eight to twelve years of use. Depending on the condition of the used battery, used EV batteries could provide an additional two to five years of use.
Throughout its lifetime, a battery’s ability to store and rapidly discharge electricity will become less effective with use and aging. How frequently a battery can deliver its stored energy at a specific rate depends on its degradation.
Batteries are likely to lose their performance when they are used more often than they should, subjected to rapid charge and discharge cycles, and exposed to high temperatures.
A few battery modules that are in good condition, with minimal degradation and no defects or damage, could likely be refurbished and reused as replacements for the same model vehicle, given the light-duty cycles experienced by EV batteries.
Rebuilt or refurbished batteries have been offered by major automakers, such as Nissan and Tesla, as a replacement for original batteries in electric vehicles under warranty.
The value of used energy storage
A repurposed battery storage system has to compete against new battery storage at the same cost in order to be economically viable. There are currently several processes that must be performed on used batteries before they can be used for stationary storage. The costs and time involved in these processes are high.
It is necessary to test each battery pack separately to determine its remaining health, as this state is influenced by a variety of factors, including climate and driving behavior for each retired system. After fully discharging the batteries, they must be re-configured to meet their new application’s energy demands; in many cases, they are disassembled, tested, equipped with a new battery management system (BMS), and packaged again.
The total cost of a second-life battery can range from $40 to 160/kWh, depending on the ownership model and upfront cost of the battery. At the end of 2019, new EV batteries cost $157/kWh. A calculator for repurposing batteries has also been created by the National Renewable Energy Laboratory (NREL) that takes into consideration factors such as labor costs, warranties, and initial battery cost and size.
Comparing new and repurposed EV battery pack costs
There is a considerable amount of downtime associated with distributed energy storage applications where batteries are not cycled. Second-life batteries offer the greatest economic value when they provide multiple services at once. Value stacking is the process of bundling services together to boost energy storage economics.
A customer may install a so-called behind-the-meter storage system primarily to reduce electricity costs by avoiding demand charges (excess electricity costs). A power outage may also be a concern for the customer. In addition to reducing the need for new power plants and balancing out large changes in electricity demand or supply, distributed storage can be used by electric utilities behind and in front of the meter.
Identifying and capturing each of these value streams is one of the main challenges for commercial batteries (new or used).
It will be difficult to develop fair compensation for batteries’ enhanced capabilities within these storage markets for the services they provide. Furthermore, the value of the services derived from batteries will need to be quantified in order to decrease uncertainty.
Customer energy management
To reduce energy costs and improve system resilience, customers can deploy energy storage ‘behind the meter’.
By charging higher rates for use during peak hours, time of use rate structures (TOU) encourage customers to shift their energy use to off-peak hours. Another mechanism for rewarding commercial customers for reducing load for a short period is capacity bidding, which is part of demand response. During peak hours when reducing customer load is advantageous, storage can be implemented by charging when electricity is cheaper, then discharging during peak hours when electricity is cheaper.
The use of second-life batteries in load shifting applications behind-the-meter provides an environmental benefit as TOU rates shift toward evening hours. This is because they charge on cleaner electricity during the day, then displace the demand for energy normally supplied by natural gas peaker plants during peak hours.
As well as balancing wind and solar generation’s intermittency, battery storage can be used directly. When onsite generation is greater than demand, customers can take advantage of storage; energy can be stored, then discharged during periods of “lull.” Some private systems might also benefit from on-site storage rather than net metering.
Utility scale services
Electric utilities can benefit from distributed energy storage in a number of ways. In addition to capturing these different value streams, a key barrier to second-life EV batteries and distributed energy storage in general is that of grid services storage can provide. The four types of grid services storage can offer are as follows:
- Frequency regulation – Describes the importance of maintaining a balance between generation and demand on the grid
- Transmission and distribution – A storage solution could help alleviate congestion by upgrading this infrastructure, but it’s expensive
- Spinning Reserves – In case of an unexpected event, reserve generation can usually be provided on short notice
- Energy arbitrage – When the demand for energy exceeds the generation, excess energy can be stored and utilized.
Existing behind the meter pilot projects
There are several pilot projects using second-life LIBs in energy management strategies (Table) for customers of all sizes. A 192kWh/144kW Nissan Leaf battery system is installed at Nissan’s European headquarters in Paris, France. The battery system allows Nissan to manage demand and benefit from TOU electricity rates.
Another example of a behind-the-meter system paired with solar PV can be found at the Robert Mondavi Institute at UC Davis. An energy-efficient 300-kWh system was assembled in a shipping container using 18 repurposed Nissan Leaf battery packs, sponsored by the California Energy Commission (CEC).
At the Johan Cruijff Arena, in Amsterdam, Netherlands, Nissan, Eaton, BAM, and The Mobility House worked together in order to install a hybrid first-life/second-life system as a result of customer demand. In addition to its 3 MW power capacity, this system has 2.8 MWh electricity storage capacity, thanks to 148 Nissan Leaf batteries. In addition to helping to cut energy costs, the battery system also provides a backup power supply of up to one hour.
One of the world’s largest battery systems, which consists of 1,000 second-life BMW i3 batteries, was commissioned in Lunen, Germany in 2016.
Developing policy to enable battery reuse
EV batteries are reused and recycled even though there is no uniform policy governing them, recent years have seen an increase in attention to end of life (EOL) management.
It is important to share crucial data about battery manufacturer, cathode material, condition, and usage history throughout the value chain so that potential secondary markets or recyclers can make informed decisions about EOL management. As a collaboration between 70 public and private organizations in 2017, the Global Battery Alliance was established to create a sustainable battery value chain, which includes repurposing and recycling.
By standardizing labelling and creating a database of battery information, the GBA’s ‘Battery Passport’ aims to improve data sharing across the value chain. Through data sharing, battery repurposing costs could be reduced and the value proposition of battery reuse could be enhanced.
Battery reuse is also challenged by logistics since used batteries are considered hazardous waste when removed from a vehicle. Hazardous waste transportation is governed by restrictions. In addition to the cost and challenges associated with transporting and aggregating used batteries, widespread reuse is also hindered.
As a starting point for thinking about the fate of used EV batteries, the waste hierarchy stresses reducing first, then reusing, recycling, and recovering energy, and finally treating and disposing of the batteries.
In addition to being eco-friendly, electric vehicles are already more sustainable than conventional gasoline vehicles. Promoting battery reuse and making sure recyclable batteries are important ways to increase their sustainability.
Existing second-life pilot projects
| Lead Entity | Location | Year(s) | Capacity |
| United Technologies Research Centre Ireland, Ltd. | Paris, France | 2017- | 88 kWh (Kangoo packs number unspecified) |
| Gateshead College, United Technologies Research Centre Ireland, Ltd. | Sunderland, United Kingdom | 2017- | 48 kWh (3 Leaf packs, 50 kW PV capacity) |
| Nissan | Paris, France | 2017- | 192 kWh (12 Leaf packs) |
| RWTH Aachen University | Aachen, Germany | 2017- | 96 kWh (6 Kangoo packs) |
| City of Kempten, the Allgäuer Überlandwerk GmbH | Kempten, Germany | 2017- | 95 kWh ( 6 Kangoo packs, 37.1 kW PV capacity) |
| City of Terni, ASM Terni | Terni, Italy | 2017- | 66 kWh (Kangoo packs number unspecifed, 200 kW PV capacity) |
| Daimler, Getec Energie, The Mobility House, Remondis | Lunen, Germany | 2016- | 12 MW, 13 MWh (1000 i3 packs, 90% 2nd life) |
| Nissan, Eaton, BAM, The Mobility House | Amsterdam, Netherlands | 2019- | 3 MW, 2.8 MWh (148 Leaf packs, 42% 2nd life) |
| Daimler, The Mobility House, GETEC ENERGIE, Mercedes-Benz Energy | Elverlingsen, Germany | by 2020 | 20 MW, 21 MWh (1878 packs, 40% 2nd life) |
| Mobility House, Audi | Berlin, Germany | 2019- | 1.25 MW, 1.9 MWh (20 e-tron packs, 100 % 2nd life) |
| UPC SEAT, Endesa | Malaga, Spain | 2016- | 37.2 kWh (4 PHEV packs, 8 kW PV) |
| BMW, Vattenfall, Bosch | Hamburg, Germany | 2016- | 2 MW, 2.8 MWh (2600 i3 modules) |
| Renault, Connected Energy Ltd | Belgium | 2020- | 720 kWh, 1200 kW (Kangoo packs number unspecified) |
| Nissan, WMG: University of Warwick, Ametek, Element Energy | United Kingdom | 2020- | 1 MWh (50 Leaf packs) |
| UC Davis, California Energy Commision, Nissan | Davis, CA, USA | 2016- | 260 kWh (864 Leaf modules, 100 kW PV) |
| BMW, EVgo | Los Angeles, CA, USA | 2018- | 30 kW, 44 kWh (2 i3 packs) |
| UC San Diego, BMW, EVgo | San Diego, CA, USA | 2014-2017 | 108 kW, 180 kWh (unspecificed number of mini E packs) |
| General Motors, ABB | San Francisco, CA, USA | 2012 | 25 kW, 50 kWh (5 Volt packs, 74 kW PV, 2 kW wind turbines) |
| Toyota | Yellowstone National Park, USA | 2014- | 85 kWh (208 Camry modules) |
| Nuvve, University of Delaware, BMW | Newark, USA | 2019- | 200 kW (unspecificed number of mini E packs, integrated with V2G in addition) |
| Nissan Sumitoto (4R Energy), Green charge network | Osaka, Japan | 2014- | 600 kW, 400 kWh (16 Leaf packs) |
