Rather than mining rare metal materials from scratch, Honda’s latest findings make recycling an option

August 2013 - Economy, eco-friendly, carbon footprint—all terms frequently used for industries to promote conscientious production. Today’s minds are searching for ways to produce with minimal damage to the environment while maintaining quality and reliability. These concerns have never been more prevalent for the automotive industry, which not only has consumers asking for better options but also government mandates to adhere to. Today’s car companies are designing more fuel-efficient, electric-run hybrid cars and considering affordable price points to reach a wide range of customers. 

Engineers continue to fine-tune designs, keeping in mind the need to reduce the amount of fossil fuel needed to run today’s vehicles. At Honda Motor Co. Ltd., Tokyo, researchers are addressing the efficiency of reusing materials to continue progress. With more and more vehicles using batteries, what happens to those batteries after their lifecycle becomes an important consideration. In March 2013, Honda announced its molten salt electrolysis process after previously announcing that it had begun extracting an oxide containing rare earth metals from used nickel-metal hydride batteries.

According to the company, it has successfully extracted metallized rare earth that can be used directly as negative-electrode materials for nickel-metal hydride batteries. The process extracts rare earth metals at more than 99 percent purity. As a result, the process allows the extraction of more than 80 percent of rare earth metals contained in nickel-metal hydride batteries.

The entire process, from disassembling through the molten salt electrolysis process, takes place at Honda’s partner’s plant, Japan Metals & Chemicals Co. Ltd., Tokyo. While unable to discuss how long the process takes, the capacity of the plant is 1,000 hybrid car battery units per month, says Tomohiro Okada, media relations, corporate communications division, Honda Motor Co.

Ongoing impact

Once the life of a battery has run its course, the extraction process enables automakers to reuse old batteries to complete up to 80 percent of the rare earth metal needed for reuse—leaving only 20 percent of new rare earth metals to be mined. “Extracted rare earth metals are the same quality as the rare earth metals from the mine,” Okada says. “Therefore, there is no special process on the battery manufacturer side.”

Any impact on the industry will not be immediate, Okada says. At the moment, the price of rare earth metals is not particularly high. “However, it is necessary to proceed with the reuse of rare earth metals and secure a stable procurement route for the industry overall because rare earth metals are precious metals,” he explains. The pricing between extracted rare earth in this process and rare earth from the mine is very similar. 

Once batteries are collected, they are transported to a disassembling/scrapping facility, followed by calcination, pulverization and sorting; after that, active substances undergo acid dissolution, producing oxide that contains rare earth metals. Then molten salt electrolysis is applied to the rare earth metal and the material can be reused as magnets in motors for new Honda hybrid vehicles.

Since the company’s initial announcement in March 2013 of the extraction process using molten salt, Honda has announced that it has agreed with TDK Corp., Uniondale, N.Y., and Japan Metals & Chemicals, to jointly pursue the reuse of a rare earth metal extracted from nickel-metal hydride batteries in hybrid vehicles for use in the magnets of new hybrid vehicle motors. “The three companies will begin detailed discussion toward the reuse in motors and begin the process as soon as sufficient volume of used nickel-metal hydride batteries is secured,” Okada says.