Solving Two Key Design Challenges for EV Charging

As auto manufacturers upgrade electric vehicle (EV) designs and nations around the world embrace EVs, the EV market is poised to skyrocket. EVs are predicted to capture 20% of global new car sales by 2025 and 50% by 2030, according to UBS Investment Bank.

But standing in the way of these predictions are some harsh realities. For example, limited driving range, slow charging time and a lack of public charging infrastructure have left many would-be EV consumers waiting on the sidelines. On the other hand, government efforts to build out charging infrastructure and recent improvements to battery technology may accelerate mass adoption.

One of the consistently reported criticisms of electric vehicles (EVs) has been that they take longer than a gasoline engine to refuel. 

How much longer depends on the charging method, as well as the type of vehicle and when it was built. Level 1 charging, used in home garages, is the slowest, taking 40 to 50 hours, according to the U.S. Department of Transportation. Level 2, used for both home and commercial charging, requires 4 to 10 hours of waiting. With the fastest method, DC fast charging (DCFC), commercial customers can charge their batteries to 80% in 20 minutes to an hour.  

Despite the convenience of charging at home, consumers show a marked preference for a speedy charge. In a 2020 Fuel Institute survey, over half said they would be willing to pay more for DC fast charging.

Manufacturers are well aware of customers’ desire for faster charging and have been raising the voltage to speed up the clock. But it’s a tricky business. Overly rapid charging can damage batteries, reducing their lifespan and performance, and in the worst cases, cause catastrophic failure of the batteries. And more power doesn’t necessarily equate to a quick fill across the board since charging slows down as batteries age. 

Charging is also affected by battery configuration, which varies wildly, not only among manufacturers but among models. Configuration is hugely important to automakers, who use it as a differentiator in creating EV designs ranging from sporty to strictly utilitarian. 

Some manufacturers are investing in charging stations, where battery configuration variations can come into play. For example, Tesla has invested in a program to build a national network of superchargers that charge an EV in just 15 minutes.

The quality of the electronic components used within an EV charging station is pivotal for its performance and longevity. Connectors must be carefully selected to address key design challenges: high currents, space constraints, electromagnetic interference (EMI), signal integrity and thermal management. 

For optimal signal integrity, all connectors should be designed with controlled impedance. This prevents reflections (signal bounce-back) due to impedance mismatches, ensuring clear and accurate signals with minimal noise and crosstalk.

High currents and thermal issues within EV charging stations are closely linked. To accommodate the large currents flowing through the charging system, prioritize connectors with large contact areas and high current ratings. However, high currents generate heat, especially in compact charging stations. Address this with low-resistance connectors, integrated heat sinks and adequate ventilation.

Additionally, select shielded connectors with metal shells and EMI gaskets to minimize external interference. Effective grounding techniques further minimize EMI, providing accurate data and power transmission. 

The reason batteries come in so many configurations is simple: batteries still need considerable improvements. For example, not every EV can handle DC fast charging, limiting the benefits of rapid-charging infrastructure.

There is a clear need for experimentation and innovation in batteries so EVs can take full advantage of the rapidly growing charging infrastructure. Yet this has been a challenge because EV batteries are difficult and costly to manufacture — but this  is changing. 

For example, Volfinity, an interconnect solution for battery cell contacting systems that uses a flexible printed circuit (FPC) board to connect cells to the monitoring system and the various ports. This innovation eliminates the need for manually-wired daisy chain connections which can introduce configuration errors. The setup is also more resistant to degradation than individual wires, while being lightweight and less costly to ship.   

Building batteries faster and more cost-effectively will give manufacturers more time and money to innovate their designs. It will also enable them to experiment with new ways to speed charging safely and extend battery lifetimes. 

Even with these constraints, the driving range has greatly improved. Many EVs can now travel 200 to 300 miles before needing a recharge.

But then what? Drivers hundreds of miles from home can’t plug into a charger in their garage, and charging stations are few and far between. That has been a sticking point for consumers, 14% of whom have decided not to consider an EV because of concerns about the lack of available charging infrastructure, according to Deloitte’s 2022 Global Automotive Consumer study.

Changing and expanding the landscape of EV charging takes more than just financial resources, though. The Tesla investment and pilot program for a national network of superchargers is just the start. For the EV market to survive and thrive, a more plentiful charging network must be achieved without sacrificing safety and reliability.

Once it’s time for a driver to plug in, whether at home or on the road, a safe and reliable user experience is critical. Reliable components and user-friendly designs must be key priorities as the EV charging network rapidly expands. Otherwise, both brand reputations and the rate at which EV technologies are adopted could be at risk. 

The new charging station rollout is also likely to be accelerated by changes in economic forces. For example, the Department of Energy recently released a memorandum of understanding to coordinate agencies and the private sector to build a vehicle-to-everything (V2X) infrastructure. Bidirectional charging capabilities will allow mobile batteries in homes and workplaces to store a charge during the day and then give power back to the grid during peak hours. 

Operators are also finding novel ways to make money from stations. For example, some add digital screens to their charge points to provide customers with promotions if they shop at neighboring restaurants, shopping centers and theaters while waiting for a charge. Others are pursuing vision-enabled chargers that can collect customer data, including demographics and the makes and models of their cars. Still, others may display local televised sports events or other entertaining, revenue-driving content.

For any business, charging kiosks serve as a branding opportunity, with distinctive designs supporting corporate messages. For example, automakers are beginning to deploy kiosks at their dealerships, with designs chosen to portray values like “relaxed luxury” or “forward-thinking tech.”

Though the exterior design is dependent to a large extent on interior parts, flexibility is increasing. For example, Molex can build busbars in a variety of shapes, dimensions and coatings, allowing companies the flexibility to meet their design needs while maintaining manufacturability.   

Though many hurdles remain for EV battery charging and infrastructure, forward momentum is evident, inspiring manufacturers, suppliers and businesses to let their ideas take flight.

As the EV charging infrastructure expands along roadways and into the home and consumers demand faster, more efficient charging experiences, the emphasis for high quality connectivity is paramount. The safe and reliable use and maintenance of charging stations is heavily dependent on ensuring risks of shock, fire, overcharge and failure are at a minimum. 

Molex’s 80+ years of innovative connectivity is helping realize the world-wide charging network of tomorrow. Our high-power busbars, cable assemblies and IP-protected connectors and solutions designed to minimize heat ensure long-term operation and are critical to a safe experience for user and connected vehicle alike. How else is Molex helping build EV charging infrastructure? Take a look to learn more.