- 1. Lead-Acid Batteries
- 2. Nickel-Metal Hydride Batteries
- 3. Lithium-Ion Batteries
- NMC-Type
- LFP-Type
- 4. Supercapacitors/Ultracapacitors
- 5. Solid-State Batteries
Here's your crash course in basic EV battery technology, from where we started to where we're heading.
Just as combustion technology has evolved over the last 140-odd years since Karl Benz invented the Benz Patent Motorwagen, so too will battery technology as EVs become widely adopted. Electric cars are technically nothing new, dating back to the early 1900s and being flirted with throughout the 20th century, but only now have they reached the mainstream. In the last 30 years, we've seen several battery technologies, and looking to the future, there are exciting developments on the horizon. So here's your crash course in EV battery technology to prepare you for what's to come.
1. Lead-Acid Batteries
The oldest battery technology, and one that is largely defunct from an EV perspective, is lead-acid. These are most similar to the regular car battery you'd find in a combustion car, and are also used to power forklifts and golf cars. But they found use in early EVs, too, with the General Motors EV1 using 16.5-18.7 kWh lead-acid batteries in early models to give it a 55-mile range.
But as an early technology, lead-acid batteries were far from perfect. They were heavy, had low specific energy, struggled in cold weather, and had to be replaced every few years, making them less than ideal.
2. Nickel-Metal Hydride Batteries
The evolution of EV batteries came in the form of nickel-metal hydride (NiMH) cells, which have been used in many hybrid cars and early mainstream EVs like the Nissan Leaf. The big upside to NiMH batteries over lead-acid ones was their long lifespan and significantly higher specific energy, meaning a battery of comparable weight could provide far more power, and, if looked after and charged correctly, could easily outlast a lead-acid battery.
But NiMH batteries were not without their flaws, and they too struggled in cold climates. They were also more expensive to produce, discharged energy too quickly when not in use, were not as efficient, and had to be charged very specifically to avoid long-term damage.
3. Lithium-Ion Batteries
The current gold standard in battery technology is lithium-ion. It started out as an advancement of technology developed for laptops and cellphones and had a typically long lifespan and high energy density. Early Li-ion cells were highly temperature-sensitive and posed fire risks if charged incorrectly or punctured. These batteries have been developed relatively thoroughly and are the mainstream option now available, with new chemistries making them more stable, energy-dense, and easier to recharge. As they are heat-sensitive, they need to be pre-heated to a correct operating range to effectively retain charge and maintain battery life, which is why a pre-heating function is included in many EVs. Within the lithium-ion field, there are a few variations:
NMC-Type
Named because of their reliance on nickel manganese cobalt oxide, NMC-type lithium-ion batteries are currently the most common in many BEVs. While these were easily producible and relatively stable, they are falling out of favor for a number of reasons. First, they're limited to a lifespan of approximately ten years, and second, they are prone to thermal runaway. Nickel and cobalt are also contentious, largely due to the unethical sourcing of these elements from their primary markets, which has driven manufacturers to other solutions.
LFP-Type
LFP batteries are rapidly taking over as the norm, and replace the nickel and cobalt with iron and phosphorus in their cathodes, materials that are more widely available globally and easier to acquire in an ethical fashion. They are heavier than NMC batteries, resulting in lower energy density and less range for their weight and size. LFP batteries also struggle with cold temperatures, which is why manufacturers have developed pre-heating cycles to keep them within optimal temperature ranges. They are cheaper to produce, have a higher heat threshold making them less prone to fires, and have a longer lifespan with less degradation. With the odds already in their favor, they also charge quicker and can discharge more rapidly, making them ideal from a charge rate and performance perspective.
4. Supercapacitors/Ultracapacitors
The terms ultracapacitor and supercapacitor are interchangeable and are technically not batteries. They are, however, supplementary power sources storing power in a polarized liquid between an electrode and an electrolyte that have been used in high-performance hybrid supercars and can play a role in supporting performance EVs. These are short-term storage solutions that can rapidly charge and discharge, yielding fantastic boosts in performance in short bursts, like under acceleration, while rapidly charging under braking. As supplementary power sources on a performance EV, the potential for supercapacitors/ultracapacitors is immense.
5. Solid-State Batteries
Widely regarded as the future of battery technology in EVs, solid-state batteries rely on a solid electrode and solid electrolyte instead of liquid or gel polymers as found in all the battery types mentioned above. Theoretically, solid-state batteries would revolutionize BEVs, as their solid makeup would vastly increase charge and discharge rates, improve energy density immensely, reduce weight, decrease the potential for fires, and improve cyclability and longevity. They are battery technology perfection, relatively speaking. However, development is still at an early stage, and despite it coming along in leaps and bounds, it is not yet ready for mass production. As an early technology, it will be expensive until it reaches a point in its development curve where it can be widely adopted, but the auto industry is rapidly working towards this point arriving sooner rather than later. Some manufacturers will even have working solid-state battery prototypes later in 2023.
Keyword: Top 5 Battery Technologies Shaping The Future Of Electric Mobility