What is a Second Life Battery?

Once a battery reaches the end of its useful life for E-buses, it will still retain 60%–80% of its initial capacity. This creates opportunities for such batteries to be re-used in a second-life application before they are eventually being recycled.

Once a battery has been in use for 12 to 15 years, it becomes unusable. As the electric vehicle battery, also known as the “traction battery,” experiences rapid charging and discharging currents under fluctuating temperature conditions during its use in an E-Bus, the battery undergoes degradation.

When this degraded battery is being re-used in other applications after its first life, it is called a second-life battery.

Throughout this article you will understand the term “second-life battery” and the required actions that need to be taken to prepare a battery for its second-life.

Challenges of Second Life Batteries

Second-life batteries increase shipping costs as they require handling by certified personnel. Battery modules differ in form factor, chemistry, and other aspects between vehicles, which makes it challenging to mix modules for second-life applications due to increased variability.

If lithium battery (LIB) modules perform well at the end of their useful life, they could be reconditioned into new lithium batteries for vehicles.

This reconditioning process reduces the availability of LIB modules for second-life applications, posing a challenge for the second-life battery market. However, it offers the benefit of extending battery life.

Manipulation of second life batteries. Balasaheb (2022)

Process Certification of Second Life Batteries

Certification is necessary to ensure compliance with regulations and standards related to transportation and electrical safety. Reused electric vehicle batteries go through a three-step process:

• Assessment: Battery engineers evaluate the batteries by considering the manufacturer’s history and the end user’s information to determine their potential for reuse.
• Reconditioning: The batteries may be utilized as they are in certain instances, but in some cases, they may require reconditioning based on the intended application.
• Recertification: Finally, the manufactured battery must undergo certification in accordance with its intended usage. This certification encompasses compliance with transportation regulations as well as electrical safety standards.

Course Mascot. PEM Motion (2023)

Certification guarantees that reused EV batteries adhere to safety, performance, and regulatory benchmarks, instilling confidence among stakeholders, users, and the overall market

Application of Second Life Batteries

Two distinct categories exist within the domain of energy storage services. These categories differentiate energy storage systems based on their placement about the electricity meter, defining their specific applications and functions.

Behind-the-Meter Storage Services (BTM)

Residential or commercial applications used to provide backup power in the event of a power cut. Most homes are behind the meter, which means the electricity must come through the meter.

Front-of-the-Meter Storage Services (FTM)

These are utility-scale services for applications such as frequency regulation, voltage support, and excess renewable. FTM means that the application works before the electricity goes to the end user through the meter.

Icon representing a battery. Pixabay (2023)

There are further utilizations for second-life batteries, including:

Electric vehicles with low power consumption

They can be used to power slow-moving vehicles such as golf carts, forklifts, etc., but cannot be used to power passenger vehicles.

Electric vehicle charging

50-300 kWh battery systems that enable direct current (DC) fast charging to reduce peak demand from the grid and lower charging costs for the charging station operator and vehicle users.

Backup services for telecommunications and data centers

Powering telecommunications towers is currently the most significant Second Life application in the world. Data centers, which require stable power, are a potential market.

The Lifecycle of an EV Battery

When an electric vehicle (EV) battery no longer meets performance expectations, it is exchanged for a new one.

The used battery is removed from the vehicle for one of the following three purposes as shown in the next diagram:

1. Disposal: Packaging may be thrown away if damaged or in regions without adequate market structures or regulations.
2. Reuse: Packs can be reused for a second life application in energy storage services. This is appropriate for their reduced performance capabilities.
3. Recycling: Packs can be processed to extract valuable rare earth materials.

Click to expand. EV battery life cycle. PEM Motion (2023)

Conclusion:

When dealing with EV batteries, it is essential to understand the factors influencing the service life and the significance and motivation behind extending the battery’s second life.

The second battery life refers to new non-automotive uses after the first initial use in a vehicle.

Second-life batteries are evaluated and repaired if necessary to ensure their suitability and reliability for new non-automotive uses after their initial use in a vehicle.

Although the battery no longer meets the power and energy requirements of a vehicle, it is still capable of storing energy. Like this, it can still have a useful second life of up to 10 years in other applications.