Until recently, hybrid electric vehicles (HEVs) ran on nickel metal hydride batteries, which offer significant improvements over traditional lead-acid batteries. For example, nickel metal hydride batteries deliver twice the power output for the weight (energy density) compared to lead-acid batteries. Nickel metal hydride batteries have worked well in (non-plug-in) hybrid electric vehicles (HEVs), as these batteries are designed to allow for constant discharging and recharging and are not expected to store and provide large amounts of energy. However, they are reaching the end of their advancement potential.
Plug-in hybrid electric vehicles (PHEVs) and pure battery electric vehicles (BEVs) make significant additional demands on battery technology that nickel metal hydride batteries are not equipped to handle. Unlike HEVs, which maintain a narrow state of charge window, PHEV batteries are intended to be depleted to a low level when they are the primary energy source for the vehicle. And BEVs are designed to run solely on battery power. The batteries used in PHEVs and BEVs must function well in a wide range of conditions; tolerate running until nearly depleted and then being fully charged; store and provide a lot of power; last a minimum of 10 years or 150,000 miles; and, ideally, be compact and lightweight. Because nickel metal hydride batteries have significant limitations for such applications, automakers, including Ford, are now offering lithium-ion batteries for current-generation HEVs and for PHEVs and BEVs. These batteries are lighter and smaller than nickel metal hydride batteries. Even so, the technology is still evolving, as discussed below, and costs are still relatively high.
It is also important to have a plan for recycling batteries at the end of their useful lives to minimize the material going to landfill.
Battery technology has been evolving. The following table shows how new battery technologies, such as the nickel metal hydride batteries used in previous HEVs and the lithium-ion battery technology in the current generation of electrified vehicles, compare to the traditional 12-volt lead-acid battery.
|Lead-Acid||Nickel Metal Hydride (Ni-MH)||Lithium-Ion (Li-ion)|
|First commercial use||1859||1989||1991|
|Current automotive use||Traditional 12-volt batteries||Developed for first-generation hybrid vehicles||Developed for current-generation hybrid electric and battery electric vehicles|
|Strengths||Long proven in automotive use||Twice the energy for the weight compared to lead-acid; proven robustness||About twice the energy content of Ni-MH and better suited to plug-in electrified vehicle applications; by taking up less space in the vehicle, provides far greater flexibility for automotive designers|
|Weaknesses||Heavy; its lower energy-to-weight ratio makes it unsuitable for electrified vehicle usage||High cost (four times the cost of lead-acid); limited potential for further development||Expensive until volume production is reached|
|Specific energy (watt hours per kilogram)||30–40||65–70||100–150|
|Recyclability||Excellent||Very good||Very good|
All of Ford’s newest electrified products use lithium-ion batteries, which offer a number of advantages over the nickel metal hydride batteries we used in the past. For example, they are generally 25 to 30 percent smaller and 50 percent lighter, making them easier to package in a vehicle.
The Focus Electric is powered by a lithium-ion battery system that utilizes cooled and heated liquid to regulate battery temperature, extend battery life and maximize driving range. The innovative thermal management technology helps the Focus Electric operate efficiently in a range of ambient temperatures. Advanced thermal management of lithium-ion battery systems is critical to the success of all-electric vehicles, because extreme temperatures can affect performance, reliability and durability.
Ford is also assisting in developing end-of-life recycling infrastructure in the U.S. for nickel metal hydride and lithium-ion batteries, both of which are high-voltage batteries. For example, we are providing educational material on battery removal, transportation and recycling, as well as a call center for end-of-life vehicle dismantlers through the End of Life Vehicle Solutions Corporation (ELVS). (The ELVS, of which Ford is a participating member, was created by the automotive industry to promote the industry’s environmental efforts in recyclability, education and outreach, and the proper management of substances of concern.) We are also connecting scrap buyers with dismantlers who have high-voltage batteries to recycle. In addition, Ford is working with DTE Energy to develop stationary energy storage systems from vehicle batteries that have reached the end of their useful life in vehicles. Ford engages with all the parties that handle end-of-life batteries, including customers, local authorities, emergency services (e.g., tow trucks and first responders), dealerships, independent workshops and garages and vehicle recyclers. Customers can recycle their batteries with local recyclers or bring them to any Ford or Lincoln dealer for no-cost recycling.
As the widespread electrification of automobiles moves closer to reality, a new set of concerns is emerging regarding the environmental and social impacts of extracting and processing key materials needed to make electric vehicles. For example, there are concerns about rare earth metals, which are used in electric motors for vehicles, wind turbines and other advanced technologies; also, a better understanding of mining processes is required.
Significantly accelerating the production of electric vehicles is likely to require the use of much greater quantities of lithium and rare earth metals. Currently, production of these resources is concentrated in a few countries, including Chile, Bolivia and China, which has led to questions about the adequacy of the supply of these resources and the potential for rising and volatile prices as demand puts pressure on existing supplies. In addition, there are concerns about geopolitical risks posed by the limited availability of these materials. Could we be trading dependence on one limited resource (petroleum) for another? Attention is also focusing on the possibility of risks such as bribery and corruption and the potential for environmental and human rights abuses. Finally, the use of water in the production of these materials needs to be considered.
We take these concerns very seriously. With scientists at the University of Michigan, we have conducted and published a study of lithium availability and demand. We found that there are sufficient resources of lithium to supply a large-scale global fleet of electric vehicles through at least the year 2100.1 We are now conducting a study of rare earth element availability and demand with scientists at the Massachusetts Institute of Technology. Ford generally does not purchase raw materials such as lithium and rare earth metals directly – they are purchased by our suppliers (or their suppliers) and provided to us in parts for our vehicles. As described in the Supply Chain section of this report, our contracts with suppliers require compliance with the legal requirements of Ford’s Code of Human Rights, Basic Working Conditions and Corporate Responsibility and the adoption of a certified environmental management system (ISO 14001). We are working in our supply chain to build the capability of our suppliers to provide sound working conditions in their operations, and we assess compliance with our Code in target markets. We ask the suppliers we work with to take similar steps with their suppliers. We are also working cooperatively with other automakers to extend this approach through the entire automotive supply chain.
As part of our water strategy, we are working with colleagues at the Georgia Institute of Technology to evaluate the water requirements and impacts of powering vehicles with conventional fuels, biofuels and electricity. This work includes a study of the water requirements of lithium extraction and processing, which, based on our understanding of the extraction of lithium from brines in arid areas, we anticipate will be low.
We will continue to monitor and assess these issues for their potential impact on our electrification strategy and our sustainability commitments.