In every stationary energy storage system that it produces for customers, United Kingdom-based Connected Energy Ltd. only sources batteries that have been used in electric cars.
Double battery life, double down on emissions
Connected Energy, in Newcastle upon Tyne in northeast England, says it can almost double the working lifetime of EV lithium-ion batteries. They tend to be used in EVs for around 10 years, as per their warranty.
Customers who buy one of Connected Energy’s E-STOR systems benefit from a highly competitive product, suitable for flexible, modular and shorter or longer duration energy storage deployments.
As well as second-life batteries and a management system, the E-STOR system comprises Connected Energy’s proprietary software controls. The battery storage systems are deployed at several customer sites in the U.K. and western Europe.
Typical uses include using the batteries to maximize consumption of solar photovoltaic (PV) electricity generated onsite as well as supporting EV rapid charging infrastructure. The smallest E-STOR module is 300 kilowatts (kW) in size, though a modular design enables large-scale configurations.
The company’s largest installation to date is a 1.2-megawatt (MW) system at the site of industrial user Umicore, to support its use of onsite renewable generation to power Umicore’s battery recycling operation in Belgium and earn revenue from provision of grid services. Other applications for E-STOR include microgrids and the replacement of diesel gensets for emissions-free temporary power.
Company chief executive and founder Matthew Lumsden says the idea of redeploying EV batteries for stationary storage systems came about when an automotive customer confided it was having difficulty installing EV chargers. “Energy storage was a potential solution, and this observation coincided with our ongoing research into battery degradation; the second life use concept grew from there.”
Compared with some other types of rechargeable batteries, lithium-ion batteries charge faster, last longer and have a higher power density for more battery life in a lighter, more compact format, making them ideal for applications such as EVs.
But over time, batteries become unsuitable for use in EVs. Drivers tend not to drive their cars until the battery is fully depleted, or they recharge them fully. Typically, the battery is charged to around 80 percent and discharged to 20 percent, using around 60 percent of capacity.
According to Battery University, charge acceptance fades with use and time, so the onboard battery management system requires a higher charge and a lower discharge to meet the driving range, until the result is a noticeable reduction in driving range.
EV drivers do not want to spend a disproportionate amount of their time charging their vehicle, so at some point the battery becomes unviable in that application, even though the battery still has sufficient capacity for redeployment in a different application.
In a stationary energy storage system, multiple battery packs can be linked up to provide the capacity required. A key feature of the E-STOR technology is controlling many batteries that are all slightly different.
The EV battery packs do not have to be adapted or modified in any way for use within the E-STOR system. The company’s automotive partners, who supply the batteries when they reach the end of their lifetime in an EV, only supply batteries that meet a set of specifications provided by Connected Energy. Specifications ensure that battery packs meet a minimum level of usable capacity. They also have to undergo physical checks for any damage, and the battery management system (BMS) has to be functional.
“Typically, packs are tested before we receive them. or they are supplied with comprehensive data sets from onboard use,” says Lumsden. “Suppliers tell us when batteries will become available, then we ensure we have projects set up to take them.”
He emphasizes that Connected Energy will only work with packs when it has the full support of the automotive original equipment manufacturer (OEM). “This ensures that the system is absolutely safe. It is critical that we achieve a level of safety that would mean an OEM is happy to be associated with our systems.”
Connected Energy’s initial EV partnership was with French carmaker Renault, which Lumsden describes as an “exceptionally supportive and collaborative relationship.” Today, Connected Energy has established further partnerships with a wide range of battery producers, EV automakers and other players globally.
“In terms of battery volumes, we are working to secure thousands of batteries annually to feed into our project,” says Lumsden. “The quantity of batteries required obviously depends on their capacities.”
Connected Energy also is partnering with a range of organizations to help establish supply chains and logistics models. “We are in discussions with organizations on every continent, and are part of a project called Recovas in the U.K., which includes Bentley Motors, BMW, Jaguar Land Rover, EMR Metals Recycling, the University of Warwick, the Health and Safety Executive, the U.K. Battery Industrialisation Centre, Autocraft Solutions Group and uRecycle, to help develop the value chain structure in the U.K.”
Challenges and future growth
To optimize supply chain and logistics costs, the company is now developing E-STOR systems that include separate 20-foot battery containers (shipping containers), which can be fitted out in advance, with shelving and connections, loaded up with batteries at a supplier hub and held until required before being delivered to the project site to be commissioned and integrated. Once the batteries are degraded the whole container can be passed on to a recycler.