The Latest in EV Brake Technology
Advances in electric vehicle systems are happening at record speed. Entire components are getting eliminated. What was once old is new again. But the NAPA experts are warning customers not to get ahead of themselves. Let’s slow down, stop spinning our wheels from all this momentum and start with the basics.
How do brakes work on an electric car? Almost all personal vehicles use disc brakes containing a pair of brake pads attached to a brake caliper, which squeezes the disc to generate friction and slow the wheel’s rotation. Electric cars utilize these standard mechanical brakes in cases of low speed and sudden emergency braking. In addition, an electric car brake system (found in hybrids, plug-in hybrids and full EVs) incorporates regenerative braking.
Many consumers are familiar with brakes on electric cars because of the popularity in the past decade of the Toyota Prius, which uses regenerative braking to deliver better fuel economy. Electric car brakes (regenerative brakes) capture the energy output (propulsion power) when a vehicle is slowing down, turning the electric motor into a generator for the battery pack. In more technical terms, the brake system in a hybrid or electric vehicle applies reverse current to the motor, which opens the charging circuit.
The EV’s computer system determines the amount of ‘brake’ getting applied from the backward running motor, thus decreasing the speed until the vehicle comes to a stop. In a fully electric vehicle, this controlled braking extends the travel range by replenishing the battery system. As much as 90% of everyday braking is operated by this electric power switch. The hydraulic system (aggressively depressing the brake pedal to activate brake pads) is only necessary at speeds under 3 mph (when there isn’t enough energy momentum to transfer) or at high speeds with sudden emergency braking.
This ‘brake-through’ technology has created challenges when it comes to a seamless transition between regeneration and foundation braking. To create an unnoticeable transition with no rough jitters or jumping, Porsche developed algorithms for their new Taycan model that constantly monitor the friction brake system so that the regenerative brakes create matching pressure.
Similarly, the design of the Porsche Taycan also tackles the unequal distribution of braking power between the vehicle’s two axles. Two thirds of stopping power is provided by the front axle. This means the front brakes capture 60 to 80 percent of a slowing vehicle’s momentum compared to the rear battery generator. Learn more about leveraging braking force between the axles in the January 2023 article by ElectricCarsReport, Porsche Explains Taycan Regen Braking.
The Future of EVs Might Involve Reaching Into the Past
For many decades, the advancements in brake systems have relied on improvements made to an isolated system. But with the expansion of consumer EVs, braking systems are now interconnected to the battery, powertrain and electronic conduction involved in deceleration. The way electric brake systems function has actually pushed car designers to reconsider an ‘outdated’ technology, drum brakes.
At one time, brake drums were the standard on personal vehicles until the invention of disc brake systems, which provided quicker stopping force. Because EVs require less engagement of mechanical brakes, especially on the rear axle, these newer vehicles run the risk of failing discs due to corrosion and rust from lack of use. This has generated renewed interest in rear axle drum brakes, which are sealed off from road and weather conditions. Learn more about why old-school drum brake technology is possibly the way of the future for compact commuter EVs in congested cities with How the Rising Popularity of EVs Could Lead to a Resurgence of Drum Brakes.
Because regenerative braking redirects the energy involved in stopping the vehicle, the lack of friction reduces the thermal load on your brakes and brake pads. This has led vehicle manufacturers to consider using thinner materials (like aluminum combined with cast iron) in brake pads, calipers and discs, which in turn makes EVs lighter weight and more energy efficient (longer runtime on a full battery). For a brake drum, this thinning can result in a 30% decrease in mass. However, in traditional brake systems, that large mass is required to absorb heat. So, the determining factor in using old tech for new EVs comes down to retaining enough resistance to heat-related brake fade.
Stop by NAPA Auto Care for EV Brake Maintenance
Now let’s talk about replacing EV brake pads and other components. Although mechanical brakes on a hybrid or EV are only relied on for quick, complete stopping, these components are still vital because regenerative systems are not designed for emergency braking or firmly holding a vehicle still. Relying on the motor to handle declaration does mean that brake pads for electric vehicles don’t wear out as quickly as full hydraulic brake systems on gasoline-powered combustion vehicles.
However, because they are used less (yet still exposed to moisture and grime), it is critical to ensure your EV brake pads are in good shape. This means routine maintenance and periodic cleaning every year versus wear-related replacement. For example, Tesla recommends cleaning and lubricating the brake calipers on a Model 3 once a year (or every 12,500 miles) for those who live in an area that uses road salt.
For decades Brembo Brakes have been synonymous with performance braking. Now Brembo has partnered with NAPA Auto Parts to bring superior braking performance to every driver. The Brembo Beyond EV Kit includes special Brembo brake pads and rotors designed for great stopping power with minimal environmental impact, while also offering superior corrosion protection. Also, Brembo ceramic brake pads are now available for a wide variety of vehicle applications as well. This line of brake pads doesn’t require a Brembo brake caliper, and these aftermarket brake parts work with your factory components. Of course, if you really want those red Brembo brake calipers you see in the Brembo brakes kit, they are available as well.
It is also true that fully electric cars do not require oil changes, exhaust inspections or spark plug replacement. But these prized vehicles still need brake system care, such as checking the brake fluid at least every two years. Dirty brake fluid needs a full brake system flush to prevent it from harming expensive auto parts. When in doubt, take your vehicle to a local NAPA Auto Care center near you.
Photo courtesy of Unsplash.
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