EV Battery Technology
When electric vehicles (EVs) first entered the automotive market more than a decade ago, one of the primary concerns was driving range — how far could one charge take you? Unlike traditional Internal Combustion Engine vehicles of the time, which had virtually unlimited ranges, the first generation of EVs had less than 100 miles of range on one charge and took roughly half a day to charge.
The first mass-produced all-electric vehicle, the Nissan Leaf, was equipped with a 24 kWh lithium-ion battery pack that had 73 miles of range. Its latest iteration uses a larger 40 kWh battery pack with 177 miles of range. Today, electric cars have an average range of 211 miles, but more premium models such as the Tesla Model S and the Lucid Air can now rival gas-powered cars with over 400 miles of range, thanks to developments in EV batteries.
Lithium-ion batteries have come a long way since they were first commercially used in EVs. However, calls for more efficient, cost-effective, and environmentally-friendly batteries have pushed manufacturers to look for alternatives.
Types of Energy Storage Systems
Electric vehicles primarily use three types of energy storage systems, each with its unique characteristics and applications:
Lithium-Ion Batteries
Lithium-ion batteries have been the gold standard in electric vehicle batteries since the launch of the Tesla Roadster in 2008. Known for their high energy density, lightweight nature, and relatively long lifespan, lithium batteries enabled the Roadster to travel more than 244 miles on a single charge. Comprising a cathode, anode, and electrolyte, these batteries utilize lithium ions to facilitate the flow of electrical current. The popularity of lithium-ion batteries is attributed to their efficiency, fast-charging capabilities, and versatility, making them the preferred choice for battery electric vehicles.
Nickel-Metal Hydride Batteries
Image courtesy: Journal of Power Sources
While less common in modern electric cars, nickel-metal hydride (NiMH) batteries have been widely used in hybrid vehicles. These batteries store energy through the oxidation of nickel hydroxide at the positive electrode and the reduction of a metal hydride at the negative electrode. Despite their lower energy density compared to lithium-ion batteries, NiMH batteries are known for their reliability, cost-effectiveness, and lower environmental impact.
Lead-Acid Batteries
Image courtesy: Advances in Battery Technologies for Electric Vehicles
Lead-acid batteries, a traditional yet less common technology in battery manufacturing, have been overshadowed by more advanced counterparts. However, they are still utilized in some mild hybrid vehicles. These batteries rely on the reaction between lead dioxide and lead to generate electrical energy. Although lead-acid batteries are heavier and less efficient than lithium-ion batteries, they remain a cost-effective option for certain applications.
Future Of Battery Technology
As new battery technologies emerge, the EV industry is poised for remarkable advancements, promising to revolutionize and reshape the landscape of electric vehicles and, by extension, the entire automotive industry. This will not only increase electric vehicle sales but also open up new possibilities and address key challenges in the electric mobility sector.
Solid-State Batteries Could Replace Lithium-Ion
As technology advances, battery makers have shifted their focus towards solid-state batteries as a potential successor to the venerable lithium battery. Solid-state batteries replace the liquid electrolyte found in traditional lithium-ion battery packs with a solid electrolyte, offering several advantages. These include enhanced safety, increased energy density, and potentially faster charging times. Major players in the industry are investing heavily in research and development to overcome the challenges associated with mass-producing reliable solid-state batteries for widespread use in electric vehicles.
Image courtesy: The Business Journals
One of the major carmakers investing in solid-state battery research is Toyota. The Japanese automotive giant has recently published a battery technology roadmap focusing on improving energy density, cost parity, and charging speeds of liquid electrolyte batteries. Their ultimate end goal: EVs having more than 1,200 miles of range and charging from 0 to 80% in less than 10 minutes. However, the company has dropped hints about a "breakthrough in solid-state battery tech” and possible mass production.
While some battery manufacturers are already looking into the future of solid-state technology, others are looking to improve li-ion batteries by introducing new battery materials. Sila Nanotechnologies, a U.S.-based battery manufacturer, is replacing the graphite anode, which makes up the bulk and approximately 15% of the weight of current lithium-ion batteries. The company suggests substituting this graphite anode with a variant of silicon, which it said could result in a 20 to 40% improvement in energy density for battery cells, along with faster charging capabilities.
Sodium-ion Batteries
Similar to lithium-ion batteries, sodium-ion batteries operate on the principle of ion movement between electrodes during charging and discharging cycles. However, sodium-ion batteries use sodium ions instead of lithium ions. Sodium is a more abundant and cost-effective element, offering potential advantages in terms of resource availability and affordability.
One notable challenge facing sodium-ion batteries is their lower energy density compared to lithium-ion counterparts. This limitation affects the overall performance and range of devices powered by sodium-ion batteries. However, the Pacific Northwest National Laboratory recently bared it has found a way to improve temperature management in EV batteries, which could reduce battery degradation during charging. By taming unstable aspects of sodium-ion technology and removing cobalt from the formula, PNNL hopes to manufacture batteries with better battery chemistry and lesser harmful effects to the environment.
Cobalt-Free Batteries
The University of Texas is actively engaged in the development of a lithium-ion battery that eliminates the use of cobalt as a cathode. Instead, it incorporates up to 89 percent nickel, along with aluminum and manganese. The rationale behind this innovation is the rarity, cost, and environmental impact associated with cobalt extraction. While cobalt and other critical materials can be revived and reintroduced to the supply chain through battery recycling, it is a tedious and expensive process.
In a similar development, SVOLT, a Chinese company, has entered the manufacturing scene with cobalt-free batteries tailored for the EV market. Claiming superior energy density, SVOLT suggests that their batteries can potentially extend the vehicle range to an estimated 500 miles on a single charge.
Seawater Battery Cell
IBM Research has unveiled groundbreaking battery chemistry that eliminates heavy metals and surpasses the performance of lithium-ion EV batteries today. The key materials are sourced from seawater, promising cost-effectiveness, faster charging, and higher energy density and power. Currently collaborating with Mercedes-Benz, IBM is actively working on the development of this technology.
FAQs
-
Experts believe that solid-state batteries are the future EV battery technology. Unlike traditional lithium-ion batteries, solid-state batteries utilize a solid electrolyte instead of a liquid one. This innovation in battery development offers improved safety, higher energy density, and the potential for faster charging times, addressing key challenges in electric vehicle performance and efficiency.
-
Various technologies are employed in EV batteries, with lithium-ion batteries being the most prevalent. These batteries use lithium ions to facilitate the flow of electrical current. Other technologies include nickel-metal hydride batteries, commonly found in hybrid vehicles, and lead-acid batteries, which are less common in modern EVs.
-
Solid-state batteries are gaining attention as a potential alternative to lithium-ion batteries. Unlike traditional batteries, these employ a solid electrolyte instead of a liquid one, providing benefits like improved safety, increased energy density, and the possibility of faster charging times. However, widespread adoption is still in the research and development phase.
-
Several companies are at the forefront of EV battery technology. Key players include Tesla, Toyota, Panasonic, LG Chem, and CATL (Contemporary Amperex Technology Co. Limited). These industry leaders are driving innovation and investing heavily in research and development to advance electric vehicle battery technology.