Once they reach the end of their lives, electric car batteries go through a crucial last step: recycling. The goal is to recover the maximum amount of reusable resources while consuming the minimum amount of energy.
The recycling of an electric vehicle’s battery faces a double challenge: reduce the amount of waste generated by a battery at the end of its life and encourage the reuse of as many components and resources involved in its manufacture as possible.
Since 2006 in Europe, Directive 2006/66/EC has mandated that at least 50% of the materials contained in used batteries and accumulators be recycled. It also requires that producers are obligated to collect used batteries at their own expense before recycling them on their own, or through the help of a specialist partner. Recycling electric car batteries is thus a task that falls on all car manufacturers. The exact recycling process then depends on the battery technology in question.
For a lithium-ion battery like the one that powers the Renault ZOE, recycling starts with disassembly. A single battery is in fact made up of several hundred individual lithium-ion cells, gathered into modules that are themselves combined into the larger whole that is the battery. There are also electronic components to take apart, including those responsible for controlling the battery’s operation and ensuring its safe use. The overall size of the battery and the number of its parts will, of course, vary according to its capacity.
Used or damaged batteries first have their residual energy drained before being dismantled. Structural elements, plastics, metals and soldered joints are sent away to dedicated recycling channels. The biggest step is to treat the lithium-ion cells, which are made up of several different chemical elements: lithium, of course, but also other metals like cobalt, nickel and manganese.
To recycle the cell, the different elements must be separated out before they are treated to be reused as raw materials. The technical process varies according to the company in question and the exact nature of materials involved. In some cases, the first step may be to grind everything up, followed by mechanical separation or a pyrometallurgy treatment at very high temperatures. The final stage of separation and refining is then done with hydrometallurgy.
The effectiveness of recycling methods is measured by several criteria, including the amount of reusable raw materials at the end of the process and the amount of energy expended. When recycling a lithium-ion battery, for example, it is possible to recover more than 85% of its cobalt. These different criteria come directly into play when calculating the ecological footprint of an electric car.
The challenge then becomes reusing the recycled raw materials in a “short loop” for the manufacturing of new electric vehicle batteries. Doing so reduces the need to extract and transport new resources, in keeping with the principles of the circular economy.
This same philosophy calls for the recycling stage to be delayed as long as possible by reusing batteries that no longer meet the demands of powering an electric car. Groupe Renault thus gives its tithium-ion batteries a second life as part of stationary energy battery storage systems, prolonging their years of service for as long as possible.
Copyrights : MOURON Roland, Agence : PLANIMONTEUR, Petmal