E-mobility Guide
Rosti partners with some of the world’s top producers to tackle manufacturing challenges in e-mobility.
This sector is experiencing rapid growth—driven by environmental demands and government regulations—and we’re helping bridge the gap from prototype manufacturing to mass production.
Injection molding for e-mobility
Thanks to our extensive design capabilities, Rosti has taken on the challenge of designing complex molds and in-mold features for mass manufacturing in the fast-growing e-mobility sector.
Injection molding provides significant benefits in this industry, with applications for electric bikes, scooters, public transport vehicles, and cars. It’s a repeatable, cost-effective, lightweight, and fast process, and production can be easily increased or decreased. These are ideal characteristics for ensuring reliable quality in high-volume manufacturing.
The modern battery carrier
The modern battery carrier has become an essential component for effective thermal management in electric vehicles. Manufacturers face the challenge of keeping multiple batteries cool without relying on forced-air cooling. This has resulted in the use of special channel structures within the battery carrier that allow cooling fluid to flow through or around the battery cells. The carriers Rosti has co-designed feature channels that also enable temporary (transient) cooling.
Rosti works with OEM customers to provide packaged solutions in this space. With our in-house, state-of-the-art mold-flow simulation software, we help clients turn ideas from concept into reality. Half a billion carriers will be needed to meet the future demands of the electric vehicle market. At Rosti, we’re proud to be leading the way.
Learn more about our e-mobility projects below or download this white paper.
Why injection molding is the perfect solution for large-scale e-mobility applications
A range of factors—especially government regulations and environmental pressures—are fueling the rapid growth of e-mobility. Plus, with the global commercial electric vehicle market expected to grow at a 39.9% compound annual rate—from 125,212 units in 2017 to 1,831,865 units by 2025—e-mobility research and development is moving forward faster than ever.
Traditional internal combustion engine technology that once powered vehicles is now losing ground, as today’s OEMs develop new platforms in the light-, medium-, and heavy-duty e-mobility markets. These platforms are expected to match the performance standards of conventional options. That’s not the only challenge—it’s just as tough to move from today’s low-volume prototype manufacturing using new technologies to tomorrow’s large-scale production requirements.
Rosti is already active in the e-mobility and battery market and works with many leading OEMs to use proven production methods to address current manufacturing challenges head-on. One such challenge is the battery pack carriers used in e-mobility platforms. Battery technology is crucial for allowing vehicles to run longer, and the increasingly advanced battery carrier plays a significant role. In this article, Tony Austin, Technical Director at Rosti, discusses battery technology concerns and explains why injection molding should be OEMs’ go-to manufacturing process.
The battery carrier: Then and now
Looking under the hood of any conventional ICU-driven vehicle, you’ll see that the battery carrier is a mostly passive part. Usually made of metal, it’s meant to support the traditional lead-acid battery and offer some protection in case of impact. However, as e-mobility vehicles have developed, the battery has become the heart of the system.
Both vehicle reliability and driving range depend on the battery technology used, so any risks to battery performance—such as hot climates—must be addressed. In short, higher ambient temperatures shorten e-mobility battery life: the hotter the batteries get, the faster chemical reactions happen and the more quickly the battery discharges.
Independent studies have shown that a battery’s self-discharge rate doubles every time the temperature rises by 10°C. It’s also critical that batteries are protected from overheating, which is the worst-case scenario because it causes rapid damage.
Quote Style
“Independent tests have shown that the self-discharge rate of a battery doubles every time the temperature rises by 10°C”
Enter the 21st-century battery carrier
The modern battery carrier has become a crucial part of advancing effective thermal management, and e-mobility OEMs are seeking new ways to keep multiple batteries cool instead of using traditional forced-air cooling. This has resulted in special channels built into the carrier to let cooling fluid pass through or around the battery cells. In addition, the channel design enables temporary (transient) cooling.
Rosti works with OEM clients to deliver comprehensive solutions in this field. The latest battery carrier designs are often highly complex, which means making a finished part using conventional manufacturing methods like CNC machining or pressing isn’t always possible. It’s also worth noting that 3D printing—seen as a future breakthrough—still has downsides, such as the high initial investment required. Plus, it can’t currently meet the industry’s demand for high-volume production. So, what’s the alternative?
Injection molding for electric vehicle battery carriers
In the injection molding process, source material is melted and injected into a mold at high pressure. The part cools in the mold and is ejected, before the process begins again. But is injection molding the optimal manufacturing process to use for electric vehicle battery carriers? Rosti has for years been challenged by many OEMs – across multiple markets – to design complex molds with numerous in-mold features, an expertise that would almost certainly be required for battery carriers used in e-mobility applications. For example, Rosti can design the cooling channels to become an integral part of the molding. Utilizing in-house, state-of-the-art mold-flow simulation software, Rosti is able to take ideas from concept to reality, producing in one pass a part that contains all the features required of a 21st century battery carrier.
But again, is injection molding definitely the right manufacturing process for battery carrier applications? Well, another way to look at this dilemma is to think about the potential volumes required. If e-mobility reaches its potential with regard to the number of units forecasted, then manufacturing volumes are set to be very high indeed. This figure also needs to consider the vast amount of spare battery packs – and therefore carriers – that will be needed, not to mention power supplies required for other markets.
Rosti suggests that neither CNC machining nor 3D printing will be able to handle these high volumes, nor will these processes provide the target piece-part costs demanded by OEMs. Instead, a repeatable, cost-effective and fast process that offers structural rigidity is required. This is again where injection molding offers significant advantages, not least the ability to scale production accordingly.
Sure enough, upfront cost for injection molding can sometimes be slightly higher due to the need for tooling, but the engineering benefits and economies of scale must be considered. Once the upfront cost has been amortized, the price per unit using injection molding is highly competitive. What’s more, the process is very repeatable; a good characteristic when trying to ensure brand consistency and part reliability in high-volume production. A further benefit is that injection molding can reduce the number of parts needed as it offers the ability to integrate ancillary parts such as brackets. Such design freedom has obvious benefits for a bill of materials and production assembly times.
Does injection molding offer the right materials?
For this application, the key is to involve the raw material producer from day one of the project. For example, there is a huge requirement to reduce weight in battery carrier applications; it is not an option to reduce battery cell weight, so instead the carrier has to be lightened. Although injection molded solutions offer a lighter alternative to traditional metal carriers, will these parts offer the strength needed to both support the battery and protect it from external factors? Rosti’s in-depth consultations with raw material manufacturers ensure that the right composition of material is deployed; one that can deliver all the requirements of thin yet strong wall construction. Furthermore, the specified material always meets the UL-94VO flammability resistance standard, thus delivering the confidence of in-application legislation compliance.
Conclusion
As the world moves toward an e-mobility future, mass manufacturing appears to be the next challenge. Rosti is convinced that injection molding has a role to play, and through close cooperation with OEMs, a technology from the 20th century may just offer a solution for the 21st.
