The past three years have seen a major shift in the perception around electrified commercial vehicles, including trucks, driven by a variety of factors that have come together at this particular time. These factors include a growing awareness and acceptance of the impact of CO2 emissions on climate change and the dangers of diesel emissions—most notably highlighted by the Volkswagen emissions scandal—alongside a growing maturity and improved cost profile on electric vehicle (EV) technology. As a result, fleet owners and OEMs now consider e-trucks much more seriously.
Within the EV technology landscape, lithium-ion battery packs stand out as the most critical piece of the puzzle and represent the biggest hurdle before mass adoption can take place. Here I share a brief overview of the challenges the industry faces in solving the battery pack conundrum, and some of the developments that could contribute to the solution. My perspective on this topic is based on my experience as the Chief Commercial Officer for Electrification at Allison Transmission and also as CEO and co-founder of London-based Vantage Power, a company acquired by Allison in April 2019 for its work in battery pack technology, vehicle integration and connectivity.
The primary barrier to widespread e-truck adoption is the cost of the battery pack, which typically is the most expensive system in the vehicle and may represent over 50% of a vehicle’s value. Many factors contribute to the cost of a battery pack, three of the most critical being cell cost, pack cost, and if/when the pack needs replacing.
Cell cost and thermal management
Fantastic improvements have been made in the cost of cells. The cell chemistry most likely to power the e-trucks of the future—lithium ion manganese cobalt oxide (NMC)—has seen an average year-on-year reduction in price of 20.5%, from $1,160/kWh in 2010 to $176/kWh in 2018. While these numbers might look appealing, they don’t portray the full picture.
With consumer automotive companies expecting to purchase the vast majority of foreseeable cell production in the coming years, there will be little volume left available for the smaller commercial-vehicle market and getting hold of cells will become correspondingly more expensive. There are also legitimate concerns around the security of supply of cobalt—a critical element used in the production of lithium-ion cells. So, while production volumes are increasing at impressive rates, and an army of engineers around the globe are working on reducing cell cobalt content, cost will continue to be a challenging factor for some years to come.
Cells typically represent 50-75% of the cost of the total battery pack. A wide range of additional componentry is required to house the cells, and connect, control and thermally manage them. It’s important to note that there is no “one size fits all” approach to this, particularly in the e-truck space where vehicles operate in an extremely wide variety of climates and duty cycles.
For example, let’s consider the challenge of thermally managing a battery pack—an area where Allison, through its acquisition of Vantage Power, has invested heavily. In a battery pack there may be as many as 10,000 individual cells, all of which need to be heated or cooled to the same temperature within their optimal temperature band of 20-30°C (68-86°F), yet an e-truck may be operating in temperatures that vary considerably from this range.
Getting this technology implementation wrong reduces the safety, lifetime, durability and reliability of the pack, but equally, the cost and complexity of including such technology can greatly increase cost. Innovations utilizing evaporative cooling in conjunction with a unique siphoning effect can achieve the necessary thermal properties while limiting cost and complexity.
The lifetime of the battery pack is a key contributor to the total cost of ownership (TCO) a vehicle operator may experience. The capacity, or amount of energy a battery can store, diminishes over time based on how intensely the pack is used and the conditions in which it operates. It’s typically accepted that a battery pack has reached the end of its useful life once the capacity reaches 80% of its initial value.
In a vehicle with relatively light operation, this capacity level may never be reached, and the vehicle will only ever need one pack. However, in more demanding applications there may need to be a new pack installed after seven years of operation, as an example, greatly increasing the TCO of the vehicle. This means that understanding and planning on how the vehicle will be operated, and properly specifying the battery pack size is critical to controlling the through-life TCO. Technologies to increase battery pack flexibility and modularity to allow operators to specify packs of different energy capacity to overcome this issue is a prime area of development within the industry.
While batteries are certainly a critical factor in the trend towards electrification, there are other important factors that operators will need to consider. Charging infrastructure, vehicle maintenance and operating profiles will all need to be worked through. Companies around the world are mobilizing to solve these challenges, and the future of electric trucking is now closer than it ever has been before.
Alexander Schey, Chief Commercial Officer, Electrification, Allison Transmission and CEO & co-founder of Vantage Power, wrote this article for SAE Truck & Off-Highway Engineering.Continue reading »