Battery Tech is at the Heart of General Motors' All-Electric Future

Last week at the General Motors Technical Center in Warren, Michigan, the automaker’s CEO and chairman, Mary Barra, announced a multi-brand, multi-segment strategy that promises a $20 billion investment in both electric and autonomous vehicle technologies over the next five years. The result will be an extensive vehicle rollout by 2025, Barra said.

Positioning the company for an all-electric future, Barra says GM “wants to put everyone in an electric car” and asserted that “a transition to an all-electric future means a focus on sustainability.”

At the heart of GM’s third-generation EV strategy is its new proprietary Ultium battery technology developed in partnership with South Korea’s LG Chem. The new battery platform promises to offer flexibility and scalability in GM’s propulsion technology and will be applied across a broad range of vehicles, delivering an improved driving range at a lower cost.

“The crown jewel is the battery cell itself,” says General Motors

In laying out plans to grow electric vehicle (EV) sales quickly, GM stressed it has to make these automobiles profitable from the outset. By using a modular approach to vehicle architecture, combined with developing a proprietary battery technology, GM believes it has the tools to achieve this.

At the most granular level, GM decided there was long-term value in developing its own battery cell, which it could package optimally for vehicle design. The automaker deemed this a better approach than relying on bundling commoditized cylindrical lithium-ion cells, which are found as components within many other auto battery packs.

GM’s resulting “pouch cells,” which look like relatively thin rectangular slabs, can be stacked like toy bricks, allowing for superior packaging density. Think about the wasted space in between a bundle of cylindrical cells, and you can appreciate the advantage of brick-like alternatives. One of GM’s large-format pouch cells is equivalent to 20 cylindrical cells.

The pouch cells themselves are then built into battery modules, with each module containing up to 24 pouch cells. Depending on vehicle requirements, six, eight or 10 modules will be configured into a vehicle battery pack, as shown below.

Photo: Battery modules can be seen in the cutaway part of the vehicle (courtesy General Motors).

This modular approach offers GM the flexibility to create a range of battery pack sizes using common building blocks. This process allows engineers to build smaller battery packs for lighter vehicles more efficiently, while combining a greater number of modules for up to a planned 200 kilowatt-hour battery pack for the automaker’s largest SUV.

In addition to efficient packaging, reducing cost and optimizing battery performance are also among the ultimate goals, GM says. Indeed, the auto industry’s holy grail has been to reduce battery costs to below $100 per kilowatt-hour, at which point EVs should become cost-competitive with internal combustion engine cars.

In developing Ultium, GM still says it is “nowhere near the bottom of the battery cost curve” and promises to continue to drive the cost and performance envelope going forward. But the automaker confidently says its Ultium system will break the $100-per-kWh threshold and, not only that, asserts a million-mile battery life “is within striking distance.”

Ultium is somewhat future-proof, too. If an individual module fails after several years in service, instead of replacing the whole battery pack, which is today’s proposition, an Ultium pack will allow the failed module alone to be replaced — saving cost and, indeed, waste. Furthermore, if future battery chemistry changes before a module fails, an Ultium battery pack will allow the integration of a new module with a different cell chemistry since it will be able to “read” what type of new module has been installed.

The smart thing here is that GM is building a battery platform which is adaptable to developments in battery cell technology, which remains in a great deal of flux, without rendering an older battery pack or design architecture prematurely obsolete. There’s both a benefit to the company and the consumer with this approach.

Ultium could reduce the use of scarce resources 

From an environmental standpoint, although EVs have the capacity to reduce carbon emissions and improve air quality, battery components themselves are not without harmful environmental impact.

One problematic element used in vehicle batteries is cobalt which, as well as being rare, has the additional hazard of frequently being sourced from conflict zones around the world.

Alleviating this problem somewhat, Ultium batteries will use a higher nickel, lower cobalt battery chemistry which GM says results in a 70 percent reduction in cobalt content compared to the typical lithium-ion batteries available today. As the technology is further refined, GM says it is working on zero-cobalt and zero-nickel batteries, too.

As much as possible, the company says it aims to source the supply of battery materials from within North America, which should help to localize the supply chain for its new manufacturing plant being built in partnership with LG Chem in Ohio, which will be the approximate size of 30 football fields.

At end-of-life, GM says it has a 100 percent record so far of repurposing any returned battery packs for a second life. Furthermore, the company expects the new pouch cells to be easier to deconstruct for recycling when, following a reuse phase, a battery module is ultimately too depleted to be useful.

So, what does this mean for the customer?

Ultium is at the heart of GM’s new range of EVs which, coupled with a new generation of EV power units, will offer customers considerable choice of electric vehicles from the company over the course of the next five years.

Today, GM’s EV offering is the Chevrolet Bolt, a small car with a current range of 238 miles on a single charge. Out of the gate, the Bolt offered the best range in the sub-premium segment, but if its design didn’t suit a consumer's needs, there simply wasn’t any other choice.

We’ll follow up in the very near future to drill down into forthcoming vehicle offerings from General Motors — and how customers’ choices are about to become much broader.

Disclosure: The author’s attendance at the press event in Michigan was paid for by General Motors. Views expressed are those of the author.

Image credits: General Motors Corporate Newsroom