The Rechargeable Renaissance

From the design concept to product delivery and beyond, electric vehicle battery development must be a connected process if manufacturers are to achieve the greatest success.

Electric vehicle battery development must be a connected process

After years of lukewarm reception and limited funding, it looks as if the battery electric vehicle (BEV) market is finally going full throttle. According to a recent Forbes article, Schmidt Automotive Research recently reported that BEV sales more than doubled in 2020 to nearly 750,000 and jumped again in 2021 with sales of more than one million vehicles, despite an ongoing chip shortage and pandemic-related disruptions.

This simulation indicates hot and cold areas in an electric vehicle's battery pack. Such visibility allows designers to address potential problems well in advance of the product release.

As Mary Barra, CEO of GM, explained in her investor presentation, “From Automaker to Platform Innovator,” the future is about sustainability and inclusiveness, powered by batteries. Cost reduction and adoption depend on next-generation materials, and will enable new products and services, such as autonomous taxis and delivery trucks.

Carlos Tavares, CEO of the newly formed automaker Stellantis N.V. (a merger between Fiat Chrysler and the PSA Group), stated, “There's a new world coming. Now, the machine is on, and we are going fast forward.”

Green is Good

The reasons for BEV popularity are clear: higher performance, simpler maintenance, and operational cost reductions. In addition, governments everywhere continue to tighten regulations on emissions while petroleum supply and costs remain unstable, with the latter trending inexorably upward. Battery prices are coming down - an 87 percent reduction between 2008 and 2020 - albeit not to the levels the auto industry and consumers would like. Add to this a growing sense among the driving public that spaceship Earth deserves greater care than what she's seen thus far, and it's no wonder that BEV adoption is on the rise.

With the anode and cathode sitting at either side, this image illustrates the complex electrochemical environment within a typical battery cell.

Still, a great deal of effort remains before battery power overtakes fossil fuel in transportation and mobility. For instance, so-called “range anxiety,” a significant concern for many users, is slowly starting to abate. Last year, the median EV battery range surpassed 250 miles for the first time and, at the top end of the market, EV battery ranges have reached 400 miles. With next-generation battery chemistries that allow for lighter cells, EV battery ranges and lifespans will continue to increase. With that comes high manufacturing costs, potential raw material shortages (namely, lithium), and manufacturing complexity, as Chevrolet learned the hard way with its Bolt EV, the risk of fire. Governments and administrations are also addressing the shortage of BEV charging infrastructure, a situation compounded by long charging times.

Despite these not so insignificant challenges, the writing is on the wall: Battery-powered electric vehicles represent the future of road haulage and transportation. Automakers wishing to keep ahead on the BEV superhighway must adopt a flexible approach for a constantly evolving vehicle market, as well as an agile structure to adapt to the new businesses that may spawn. They must either develop in house, or partner with suppliers, to manufacture large quantities of high-energy density batteries. Those batteries must be safe, quick to charge, and provide better ranges than that of the gas and diesel alternatives.

Battery Anatomy

Accomplishing each of these will mean shifting away from the status quo, starting with the materials. As already noted, battery makers currently face strong competition for lithium, most of which is mined in Australia and South America but then shipped to China for refining. If startup companies like Sila Nanotechnologis and Ion Storage Systems have their way, however, much of that demand will shift in favor of abundant sodium or ceramic systems.

Doing so will take much more than a plentiful raw material source; it will also take visibility into the complex inner workings of batteries, whatever they are made of. That's because batteries are living things - their chemistries change over time and use, which is why they are (unfortunately) known for capacity fade, occasional combustion, and eventual failure.

Building a better battery requires a thorough understanding of the continuous interaction between the anode, cathode, and other battery materials. Designers need to model and simulate the behavior of the electrolyte as well as the mixed metal oxides electrode coatings, polymer binders, and other chemical constituents in the cell. Most importantly, they need to be able to predict how this electrochemical soup will evolve with different use profiles over Mays and miles.

Micro to Macro

Chemistry is only the beginning, however. The “battery” inside an electric vehicle actually comprises hundreds of individual parts. Comprehensive modeling of the entire system requires accurate representations of each cell, followed by the modules, and then the battery pack as a whole. As these different components and subassemblies come together, the mechanical, thermal, and electrical dynamics begin to change and the choices multiply.

Where heat buildup might not be a concern with an individual cell, nestle several dozen of them alongside one another in a battery module and the laws of thermodynamics begin to play a much larger role. Similarly, electrical carrying capacity, conductivity, and voltage levels all change – often dramatically – as batteries grow in complexity. It's only through analysis of the micro, macro, and every level in between that designers can achieve an optimal battery configuration.

Then there are mechanical and environmental considerations. The battery pack in a typical passenger car weighs 450 kilograms (992 lbs.) or more. Within are the rows and rows of the modules just mentioned, each of which must be held securely and without movement even in the face of vibration, acceleration, and possible collisions or rollovers. Such a structure calls for extreme strength, stiffness and above all, safety.

These two images show how one cell design (at left) handles impact deformation better than the other. Without advanced simulation capabilities, small differences like these would likely go undetected.

Complicating matters even further is the battery pack's operating environment, which can vary from Canadian cold to sub-tropical heat. Throw in some rain, snow, salt spray, mud and dirt, and even the most robust container designs are put to the test. The question then becomes: How to test? How to see inside the functioning battery? How can battery manufacturers assure long-term performance and dependability in an extremely complex product with no moving parts? Not only that, how can they design the system for in use, safe upgrades and updates?

Traditional automakers might suggest real-world testing, with thousands of miles cruising automotive proving grounds and weeks or even Mays in environmental test chambers. But, given the rapid pace of change in today's BEV market, such legacy testing methods are prohibitive and difficult to optimize. A better, more accurate and cost-effective solution is modeling and simulation. This provides unprecedented, iterative views within the cell at the macro-and micro-scales, without the complexity and uncertainty of older testing methods. Lastly, this can help with safety and recycling. For example, many governments are developing “Digital Battery Passports” designed to contain information on the battery pack, its lifespan and any deviation from expected behaviors. Models and connected data are a key element of this.

The Production Floor and Beyond

Once an optimized battery design is delivered, what then? A manufacturing engineer might tell you this is when the real work begins. There is an element of truth to this. As with the design process, battery manufacturing needs connected, end-to-end solutions with visibility into the product, the process and beyond. Without this visibility, which must also encompass the entire testing, fabrication and assembly process, manufacturers are left scrambling to identify the source should an issue or defect arise.

It's a steep hill to climb, to be sure, and it is made harder by the current pace of change in the EV industry. All is not lost, however. In battery innovation and production, a systems approach unifying real and virtual data with models can help manufacturers innovate more quickly, with better capabilities, at lower cost, so that they win the race to EV dominance.

From Dassault Systèmes’ perspective, such capabilities are the next step forward in enabling BEV, the next chapter in agile manufacturing, and the fundamental underpinning of a more sustainable future. Indeed, many of the G8 countries and the leading global automotive manufacturers see battery vehicles as the tipping point for a greener world.

This article was written by Michael Doyle, Material Sciences Fellow, Corporate Research at Dassault Systèmes R&D (Vélizy-Villacoublay, France). For more info visit here .