Battery battle

To help slow a changing global climate by at least eliminating the emissions that come directly from conventional vehicles that are powered by burning fossil fuels, automotive OEMs have started producing more vehicles that are powered by rechargeable electric batteries. In addition, some automakers only make electric vehicles.

Most new vehicle sales are still for ones with an internal combustion engine, but globally about 16% were for EVs in 2023, according to Puneet Sinha, senior director of the battery industry at Siemens Digital Industries Software, which is headquartered in Plano, Texas. That percentage is a far cry from the miniscule number on the roads about 15 years ago when a small wave of EVs hit the market.

“They were either very expensive or offered a very limited electric drive range,” Sinha said.

Battery manufacturers have made strides to lower the cost and increase the range while reducing the recharging time, but the quest for improving battery range and recharging time and lowering the cost continues. Earlier battery chemistries, such as lead-acid and nickel-cadmium, have been replaced primarily by lithium-ion cells. The batteries store and release renewable power by moving lithium ions through a liquid, the electrolyte, from the cathode to the anode and back again. They are known for their high power-to-weight ratio, energy efficiency and temperature resistance, as well as their low self-discharging capabilities, but a host of new battery technologies are under development or waiting in the wings. These include solid-state, lithium-air, lithium-sulfur and graphene batteries, as well as hydrogen fuel cells.

In addition, as lithium-ion batteries continue to evolve, battery companies are developing batteries with a solid-state electrolyte instead of a liquid one to enable lithium-ion batteries to operate safer and more robustly, Sinha said. “The liquid electrolyte is combustible, has certain limitations, more toward safety, but also toward the durability of those lithium-ion batteries.”

Solid-state batteries are being developed for both consumer electronic and EV applications, and tremendous advancements have been achieved during the past five years, Sinha said. “In the next five years, it is possible that we’ll see commercialization of solid-state batteries in some of the applications.”

Keeping Dangers in Check

Initially, lithium batteries were made with pure lithium metals, but manufacturers could not control the growth of dendrites, which are like stalactites and stalagmites but in a lithium battery, explained Brad Larschan, CEO of Avadain, which has a globally patented technology to manufacture high-quality graphene flakes. When lithium is charged and discharged, some of the lithium crystallizes and forms dendrites that grow from a battery’s anode and cathode and can pierce the separator layer. The consequence ranges from a short circuit to a fire or explosion.

“That’s why the lithium-ion battery was developed,” Larschan said. “It was such a breakthrough and led to widespread consumer use of lithium batteries.” The tradeoff, however, is that lithium-ion has only about 10 percent of the energy efficiency of pure lithium metal.

As adoption of EVs continues to increase, albeit in fits and starts, Sinha said battery production is forecast to grow tenfold by the end of the decade. That rate of growth is both a tremendous opportunity and challenge for companies in the entire supply chain, which includes companies that mine and process lithium, chemistry producers, cell suppliers, system integrators such as automakers and builders of the sophisticated machines that are needed for large-scale battery production.

An image of Siemens’ Sicharge D and SiE storage dispenser. Sicharge D is a companion for electric vehicle charging that features a power range of up to 300 kW DC. Image courtesy of Siemens”>

According to Sinha, manufacturing represents about 25 percent of the cost of a lithium-ion cell, partly because of a high level of scrap. He estimates that the scrap rate can reach 40 percent or more when production begins at a battery gigafactory. “Even for companies who have stable production at capacity, they struggle with a 10% or 15% scrap rate.”

One area of significant investment for battery manufacturers focuses on improving energy density, the amount of juice that can be packed into 1 kg (2.2 lbs.) of battery, Sinha said. Doing so allows an EV to go further before needing a recharge.

Because about 70% to 80% of the battery pack’s weight is in its cells, battery manufacturers are continually researching chemistries to increase the energy density in a lithium-ion cell to create lighter batteries with the same energy density, he noted.

The remaining weight is comprised of structural beams, pumps, coolant and other items in a battery pack, Sinha added. The objective is to reduce the weight of those without sacrificing the rigidity or structural integrity of the battery pack.

He noted that the key minerals that are needed to make lithium-ion batteries are nickel, cobalt and manganese, but manufacturers are looking to reduce the amount of cobalt needed because of its high cost.

One type of lithium-ion battery that is seeing an increased demand is the iron phosphate lithium battery, Sinha said, because they cost less but also have a lower energy density than conventional lithium-ion ones and, therefore, provide less range. However, they are heavier than lithium-ion batteries that have nickel, cobalt and manganese.

When manufacturing a lithium-ion EV battery, which will be increasingly performed in gigascale factories to achieve economies of scale, Sinha said it is less like building a vehicle and more like baking a cake. After mixing the proper ingredients and ensuring everything has the right properties, the cake is baked in an oven to complete the process. “It’s the same thing you need to do for a lithium-ion cell at the end of manufacturing.”

Flakes for the Future

While lithium-ion EV batteries are well-established, graphene ones are still on the drawing board. However, graphene batteries would “revolutionize” the electric vehicle industry, according to Avadain’s Larschan. “A graphene battery could almost instantly increase by three or four times the distance between charging.”