Today battery chemistries for the best cost/performance ratio, tomorrow the grail!

Pioneer in Europe with Renault ZOE, Renault Group has been committed to the development of electric mobility since 2010, with over 15 billion zero-emission kilometers travelled.

To maintain our leadership in zero-emission vehicles, we decided a few years ago to significantly increase our deep knowledge of electric vehicle technologies across the entire value chain, from raw material supply to recycling. Obviously, the battery is a key element in this value chain, and the choices we make about its chemistry are decisive.

A battery cell consists of an anode, a liquid electrolyte and a cathode. Many chemical combinations are possible, particularly when it comes to the materials used in the cathode, but none of them (for the moment) perfectly meets all the challenges of 100% electric mobility. It's all a question of compromise.

Limited range has long been an obstacle for market development, and our priority was to try to remove this obstacle. This is the main reason why Renault Group chose layered high nickel content NMC cathode active material chemistry (Nickel, Manganese, Cobalt) to maximize energy density. This chemistry currently powers the batteries of #Megane eTech and #Scenic eTech in particular.

But the market for raw materials is constantly evolving. Nickel and cobalt, rare metals have become expensive, significantly impacting the current price of NMC batteries. Keep in mind that the cathode active material account for roughly 40% of the battery cell cost.

At the same time, the progress made in LxFP olivine cathode active material (lithium iron phosphate) technology and the significant reduction in the performance gap with NMC batteries have convinced us to expand our strategy and use LxFP chemistry to further democratize electric mobility.

Although the energy density of an LxFP chemistry is still lower than NMC, major advances have been made in recent years, both in terms of autonomy and chargeability. Here are few examples:

• The energy density of battery cells using LxFP cathode increased by 38%, from roughly 300 Wh/L to a nominal of 415 Wh/L. 
• The speed of chargeability of same battery cells increased by a factor of 2 making it possible to recharge 200km of highway range in less than 18min. All this was possible due to improved electrolyte conductivity, high separator porosity, gradient electrode structure and an effective conductive network.
• The excellent abuse tolerance of LxFP chemistry enabled by its Olivine crystallographic structure made it possible to increase the battery cell size and optimize their integration thanks to a cell to pack or cell to body architecture. Who thought that we can reach more than 70% volumetric energy packing efficiency. Yes, we can! Renault did it.

All these recent progress means that, with LxFP and NMC we will play on both technologies for our future cars.

By 2025, the Group will also be able to rely on its Battery Cell innovation laboratory at Lardy. This center of excellence will enable us to anticipate technological breakthroughs and develop our expertise in evaluating cell supplier processes to guarantee quality and production costs at the highest levels. It’s a strategic tool and a competitive factor.

Our teams are already studying other innovative solutions beyond LxFP. Cathode and anode active materials chemistries that could reach maturity by 2027 to provide a superior solution. Let us give you a hint: we are combining multiple individual innovations in one cell to create a largely superior solution and breakthrough performance in service our customers and our planet. Let us quote Aristotle “The whole is greater than the sum of the parts.”

Stay tuned... more to come soon!