Manufacturing environmentally friendly electric vehicle batteries, thinking from the inside out


As battery manufacturers switch to designs that use cheaper raw materials, the premium for pure cathode materials is expected to expand. These include LFP batteries, whose cathodes contain lithium, iron, and phosphorus, and give up expensive metals such as nickel and cobalt. Kyburz has long used LFP batteries in its vehicles, and large manufacturers including Tesla are now following suit. But because the raw materials are cheap, they are less attractive to recyclers. “They need a lot of money to take them,” Groux said.

The cheap removal of the cathode from a spent battery requires a redesign of the battery from the ground up. Gaines pointed out that this has been done before, most notably lead-acid batteries, which are used to start the engines of traditional cars. More than 95% of lead-acid batteries are recycled. One reason is that manufacturers use standardized designs, which means that recyclers can use almost any battery and pass it through an automated process. Recyclers remove the main components—lead and polyurethane, a type of plastic—and then separate them in large buckets filled with water. Very simple: plastic floats; lead sinking.

Lithium-ion batteries are more complex, involve more parts and materials, and have more diverse designs. But despite this, “you don’t have to design the most difficult-to-recycle batteries like an idiot,” said Andy Abbott, a battery researcher at the University of Leicester who studies recycling-friendly designs.Battery manufacturers have some easy ways Can make the life of the dismantlers easierFor example, they can use screws instead of laser welding and choose adhesives that are easier to remove. But these small changes may be the most difficult to achieve, explained Jeff Spangenberger, who is in charge of the ReCell Center, because small costs add up to large-scale costs. It is not worthwhile for the manufacturer to spend an extra $2 for each battery to buy screws to save $1 to disassemble the battery-as long as they are not responsible for the cost recovery.

Groux encountered this problem recently when Kyburz was researching using modules to make more powerful batteries. He hopes to seal the battery with screws, but almost all Chinese manufacturers he consulted use laser welding. Nevertheless, companies like Kyburz still have certain advantages. Its vehicles are relatively low-powered and are designed to sprint around Swiss villages for several hours at a time, rather than constantly galloping over the Mojave Desert. In most cases, the company uses a single large battery without modules, so they are easier to remove. This means that Groux machines can do this in a semi-automated manner.

Of course, Tesla batteries are much more complicated. But this does not mean that they cannot be designed in a way that is at least more predictable and allows for some automation, Abbott explained.He pointed “Blade” battery, The new LFP battery produced by the Chinese car manufacturer BYD for its passenger cars, as an example of progress. LFP batteries have well-known advantages: they are cheaper than cobalt and nickel-filled batteries, have a longer lifespan, and are generally less likely to catch fire. But people think they can’t store enough energy to power cars for hundreds of miles—so the blades surprised many observers.

For Abbott, one of the most exciting changes in the design is that the battery pack is not broken down into modules. Instead, the batteries are arranged in rows directly inside the battery pack. These cells are long and rectangular—hence “blades”—not cylindrical jelly rolls. BYD found that it can pack these rectangles more densely into the battery pack than a cylinder, making the entire battery pack more powerful. Abbott did not have the opportunity to directly examine the design, but he suspects that the simplified design will make the battery easier to remove. Other companies, including Tesla, said they plan to produce battery packs without modules, although the battery designs vary.



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