Sponsored by Epic Resins.
Because the e-mobility business continues to revolutionize the best way we use EVs and LEVs, one vital query persists for engineers: How can we design a safer battery pack? A latest dialog between Joe Staller, R&D Chemist at Epic Resinsand Luke Workman, Chief Scientist at Electrical Goddessrevealed eye-opening insights into materials improvements and real-world testing that drive rugged battery pack design methods.
On the coronary heart of their dialogue is the have to deal with battery security as a foundational design aspectnot an afterthought. On the subject of lithium-ion batteries, the stakes are excessive. A single malfunctioning cell can set off thermal runaway—a speedy, uncontrollable rise in temperature and strain that can lead to fires or explosions. For engineers, stopping this isn’t simply good design—it’s non-negotiable.
Engineers are confronted with the high-pressure problem to design a low-weight, high-power battery. Want for corrosion and vibration resistance can also be important, as engineers have seen what occurs if these should not critically addressed.
Security Shouldn’t Be Non-obligatory
“Batteries have to be designed with a safety-first mindset,” Luke emphasizes. This angle shift is essential. Too usually, engineers prioritize weight, power density, or price effectivity first, assuming that every element within the pack will carry out as anticipated. However, real-world situations are not often good. For instance, each cell in a battery pack is completely different, and cell high quality defects exist. Whether or not it’s a producing defect, corrosion, or vibration abuse, the query isn’t if a cell will fail—however how. And when that occurs, the fabric surrounding the battery makes the distinction between a deliberate end-of-life, a minor incident, or a significant catastrophe.
Joe echoed the identical warning from a fabric perspective. “After we design encapsulants or potting supplies, we formulate for probably the most excessive situations,” he defined. That features thermal biking, strain surges, and flame publicity.
Understanding Thermal Runaway
Thermal runaway might be triggered by overcharging, puncturing, overheating, environmental stress (similar to corrosion) and even spontaneous cell defects. As soon as a single cell begins to vent, the chance to neighboring cells multiplies quickly. With out correct materials safety, the end result might be catastrophic.
Luke has seen firsthand what occurs when this course of goes unchecked. “We’ve completed stay abuse testing the place total modules went up in seconds,” he mentioned. Nevertheless, he has additionally examined methods the place non-cellular potting supplies and correct designs present the thermal mitigation. A rugged potting materials can imply the distinction between a localized occasion and full-blown thermal runaway propagation.
Joe explains, “The purpose is straightforward however very important: include, gradual and redirect the warmth to stop thermal propagation to adjoining cells”. At Epic Resins, we obtain this by exact polymer formulation. Fillers throughout the potting materials set off endothermic reactions that take up and carry warmth away from harmful cell initiations, serving to the fabric self-extinguish. This “buys time” for warmth to dissipate and resist combustion earlier than it will probably unfold to neighboring cells. Even when a flame does erupt, our potting and encapsulation supplies might help extinguish it, lowering the chance of fireplace propagation
Selecting the Proper Chemistry
So what materials ought to engineers use? The reply, as at all times, is determined by the applying.
Polyurethane foams supply a decrease weight and price, however compromise the energy, integrity and thermal efficiency wanted in rugged battery designs. Non-cellular elastomers usually strike the very best steadiness between efficiency and price, with good thermal and mechanical properties.
“Each software is completely different,” Joe mentioned. “It’s important to contemplate extra than simply weight—there’s no “one components matches all” for battery design.” The method begins with totally understanding the applying, its working atmosphere, and testing necessities. Properties like Tg and CTE are dictated by environmental temperatures, whereas thermal conductivity is determined by the kind and effectivity of the thermal administration system.
For security, we provide a variety of choices to mitigate thermal runaway and suppress flames, with our UL 94 V-0 flame-retardant methods. We additionally account for processing wants similar to viscosity and reactivity to satisfy manufacturing necessities. This multi-step, property-focused strategy ensures each answer is exactly matched for dependable, profitable efficiency within the area.
Actual-World Testing That Issues
Luke’s lab at Electrical Goddess focuses on real-world testing that goes properly past normal regulated checks. They check to failure, to grasp the protection margin and collect helpful knowledge by customized fixturing. That is important for validating designs for particular functions and making knowledgeable materials selections earlier than these batteries are utilized in on a regular basis life.
Manufacturing Concerns
Deciding on the proper potting materials has a big influence on manufacturing effectivity and product consistency.
Foam potting introduces appreciable variability into the method. Its construction is very delicate to temperature fluctuations, which might create bubbles or nucleation websites that alter foam density and distribution. Even small day-to-day temperature modifications can lead to inconsistent fills and potential rework. Moreover, if polyurethane foam is overfilled, it will probably broaden and overflow aggressively. This results in elevated prices with materials waste, module loss, prolonged cleanup time, manufacturing downtime and waste disposal.
In distinction, non-cellular elastomer methods supply higher manufacturing stability. These supplies are metered as homogenous liquids, freed from bubbles, they usually degas simply. Their viscosity might be tailor-made to make sure full move into all obligatory cavities for cover. The result’s a potting course of that’s simpler, sooner, and extra constant—lowering rework and bettering throughput.
Potting With out Extra Weight
Engineers make investments important time and sources into optimizing battery pack effectivity—each gram and cubic millimeter issues. However with out correct planning for cover, these positive aspects might be compromised. By designing with non-cellular elastomer potting in thoughts from the beginning, engineers can pot solely what’s obligatory—avoiding extreme materials use, added weight and pointless price.
As battery professional Luke Workman explains, gravimetric effectivity isn’t misplaced if you select a non-cellular elastomer. It’s enhanced—if utilized deliberately. “For propagation resistance, potting ought to cowl every little thing between cells. For corrosion resistance, you solely have to encapsulate the areas carrying present. It doesn’t have to be greater than that,” he says. “You may actually make environment friendly gravimetrics.”
A typical false impression is that foam is the lighter possibility. However when evaluating 2mm of froth to 2mm of a non-cellular elastomer, the load distinction is minimal. A vital level is the mechanical efficiency. Foam lacks the structural energy wanted for sturdy safety, usually requiring an outer shell to keep up integrity. In distinction, a correctly designed pack utilizing a non-cellular elastomer could also be robust sufficient to get rid of the necessity for extra enclosures, usually leading to a lighter total system.
Non-cellular potting methods may also be formulated to match software wants. Fillers and particle sizes might be adjusted to optimize each thermal conductivity and density—giving engineers the flexibleness to design for efficiency with out sacrificing weight.
A Programs-Stage Method
One of many largest takeaways from the dialog? Security doesn’t stay in a silo. You may’t rely solely on the cells, or the BMS, or the potting materials. It’s the combination of all these methods that creates security. Joe agreed, stressing the significance of early collaboration: “Deliver your supplies companion into the dialog early. The earlier we perceive your design targets, the higher we will match the fabric’s chemistry.”
Closing Ideas: Designing for Security
In the end, the message is evident: Battery security is a multidisciplinary problem—one which begins with a mindset shift towards security first, not weight and energy density. Designing for non-cellular elastomer potting and testing early gives you probably the most structurally sturdy battery. Failure to ship a protected battery the primary time may solely find yourself costing you more cash ultimately, with recollects, lawsuits and a tarnished fame.
Longevity and reliability go hand-in-hand with security. A battery designed with non-cellular potting can also be higher shielded from a thermal occasion, corrosion, and vibration.
Due to the strong nature of a non-cellular elastomer, these supplies are simpler to fabricate and extra constant. This protects you cash over temperature-sensitive foam potting. That sensitivity very simply results in materials inconsistency, over move, downtime and waste.
Whether or not you’re engineering a battery for an EV, LEV or HDEV, choosing the proper supplies and testing underneath actual situations are non-negotiable. With the proper mixture of potting materials, design, and testing knowledge, you’ll be able to dramatically scale back threat and construct belief in next-generation battery packs.
Don’t miss the complete dialog between Joe Staller and Luke Workman on September seventeenth:
Register for our webinar right here.
Extra sources:
Mitigating Thermal Runaway Case Examine
Epic Resins Battery Pack Compounds
