While only 139 Altra EVs were sold, fast forward to today’s EV market and the numbers tell a different story. Global EV sales hit one million units for the first time in 2017 ⁶ and are predicted to surpass 300 million by 2030. ⁷ Such growth stems from a desire for more sustainable transportation options. Transportation accounts for over 25% of global greenhouse gas (GHG) emissions and is a well-known contributor to local air pollution issues. ¹⁵ Electrification of the transportation sector has been suggested as a primary approach to reduce GHG emissions and improve air quality. ¹¹ As a decarbonization strategy, electrification aims to convert energy-consuming devices that traditionally run on fossil fuels to those that run on electricity or electrical storage. LIBs are the key technology advancing this process. Relative to conventional cars powered by internal combustion engines (ICEs) that run on multiple complex systems, battery-powered electric vehicles (BEVs) have a simpler internal configuration consisting of a single large battery or bank of batteries that can be charged and discharged hundreds or thousands of times during a typical battery lifetime.

When charged, an EV battery must contain a high enough energy capacity to power the propulsion system of the vehicle. Presently, common types of rechargeable batteries used in BEVs include lead-acid batteries (LABs) and LIBs. Some EV manufacturers choose LABs due to their high reliability, availability, low cost, and high recycling potential. However, they are not as widely used in EVs due to their lower energy storage capacity relative to LIBs. LIBs have significant advantages over other battery types in terms of their higher energy density and efficiency, smaller size, and lighter weight. These characteristics mean LIBs are widely used in EVs today. However, LIBs are not perfect, and current research is investigating how to improve LIB lifespan, charging rates, and driving range reliability. 10

In theory, LIBs would last forever as lithium ions move between the anode and cathode ends of a battery cell to generate a voltage and power a device. 13 However, normal aging and secondary chemical reactions cause LIBs to lose capacity over time. 8 4The point at which an EV LIB reaches end of life is determined by its remaining capacity, which is expressed as the state of health (SOH), or an estimate of the battery’s capacity to store energy compared to when it was first manufactured. 16 Currently, EV LIBs are considered to reach end of life when their SOH falls below 80%. 2 Below this, EV LIBs cannot generate enough voltage to power and accelerate the vehicle, which requires most EV LIBs to be retired after 10 to 12 years. 3

Recycling options for LIBs are currently limited, meaning most end up either stockpiled, sent to landfills, or in electric car “graveyards” in some countries. ¹ While nearly all conventional lead-acid batteries are now recycled, few LIBs are due to the high cost and challenges associated with managing the impact of the critical elements that make up LIBs, such as lithium, nickel, and cadmium, causing most to end up in landfills where leaching releases these elements into the environment. ¹² Another challenge is managing the residual energy in EV LIBs. Discarding batteries that have not been discharged leads to safety hazards such as electric shock and thermal runaway. Over 240 fires caused by LIBs were reported from 64 facilities between 2013 and 2020. ¹⁴ While most of these fires originated from smaller LIB-powered devices, the similar chemistry to EV LIBs means their larger battery packs would logically lead to larger, more dangerous fires if they continue to be discarded in landfills.

With the abundance of retired EVs, there is a market for used LIBs that still maintain 60-80% of their original energy capacity that could be met with reused LIBs from BEVs. ⁵ A circular economy for LIBs means that any residual power remaining in batteries when they reach the end of their first life should be fully used before the battery is finally disposed. A battery economy with a circular (e.g., take, make, reuse/repurpose, recycle) rather than a linear (e.g., take, make, use, discard) supply model will promote more resource-efficient battery use, ensuring the maximum electrical energy is harnessed from an EV battery before it reaches a final end-of-life state. A common circularity practice includes slowing resource loops by considering alternate use options before recycling. ² For example, second use of EV LIBs could include: 1) reuse in an EV after repair or refurbishment, or 2) repurposing in a different application requiring less voltage, such as in stationary energy storage, smaller electric-powered vehicles, or power tools. The viability of whether a battery is fit for reuse or repurposing depends on the condition and state of health of the battery. To support the circular economy and improve waste management options, potential second-life LIBs need to be evaluated against a standard to ensure they are safe for their second-use applications.

In response, technical committee 1974 was formed in April 2017 with representatives from various interest categories, including producers, regulators, government agencies, testing and standardization organizations, supply chain members, commercial and industry representatives, and general interest members.

On October 25, 2018, the first edition of UL 1974 was published by UL Standards & Engagement as the Joint National Standard for Canada and the United States for evaluation for repurposing batteries. Over the next four years of putting UL 1974 into use, ideas for revisions to the first edition were brought forward. In 2022, proposals were received from industry with suggestions for improvements to UL 1974, including a proposal to expand the scope of the standard to incorporate remanufacturing. In November 2023, the second edition was published with a revised title: the Standard for Evaluation for Repurposing or Remanufacturing Batteries.

Together, these steps help determine a battery’s state of health and if it is safe for continued use in a second-life application. Test procedures carried out during the evaluation include checking the battery’s capacity, internal resistance, charge and discharge cycling, and the battery management system controls. Of particular importance during the charge and discharge cycling test is to monitor the battery’s temperature, voltage, and current to see if the battery cells function within the manufacturer’s recommended specifications. If any values are too high or too low, then the battery is rejected from moving on to being repurposed or remanufactured. Guidance like UL 110: Ensuring Mobile Phones are Sustainable | www.standardsacademy.org 8 that offered in UL 1974 helps repurposing and remanufacturing entities assess the qualities that will determine the usability of lithium-ion batteries, which supports keeping batteries within a circular economy rather than having them end up as waste, and it improves our ability to make the most efficient use of current battery technology.