Unveiling EV Power: The Ultimate Battery Teardown Guide

Hey y’all! 👋 It’s Ashok here, and today I’m stoked to dive into some seriously cool behind-the-scenes stuff on EV batteries. I was reading an ASME Magazine article (shoutout to Agam Shah) that breaks down how a team at RWTH Aachen University in Germany literally tore apart Tesla and BYD batteries to see what makes them tick. They call it a “teardown,” and it’s basically like a surgical autopsy for batteries—super nerdy, super enlightening. I want to share the key takeaways from their deep dive, sprinkle in some context for how this matters in the real world of EV design (especially for heavy-duty applications like electric trucks), and hype up why understanding manufacturing is just as important as the chemistry itself. Let’s get into it! 🚀

Why Teardowns Are the Real MVP in Battery R&D

When you’re developing EV structures—especially at the scale of electric trucks—you often see flashy headlines about “new chemistry!” or “30-minute charging!” But putting an exotic battery chemistry into mass production is a whole different ball game. Jonas Gorsch, a research associate at RWTH Aachen, points out that scaling from lab bench to gigafactory (and then into an EV) brings tons of headaches: material sourcing, manufacturing sequences, cost targets, and quality control. In other words, your dream cell in a beaker might flop when you try to make a thousand of them consistently.

By literally taking existing, high-volume production batteries (Tesla’s cylindrical cells and BYD’s prismatic cells) and reverse-engineering them, the Aachen crew wanted to create a baseline for future designs. If you’re like me—geeking out over the structural design of electric truck frames—you know that the battery pack isn’t just a black box of kilowatt-hours. The mechanical layout, thermal management, vibration resilience, and even the laser-welded joints all matter for durability and service life.

So instead of just “paper specs,” we get a hands-on look at cell formats, material compositions, welding methods, and thermal configurations. That intel is pure gold when you’re brainstorming passive thermal strategies or crash protection for a modular battery cage in a 28-ton GCW electric truck.

Hunting Down the Batteries: Easier Said Than Done

First off, getting your hands on Tesla’s pack is like trying to score concert tickets to Beyoncé—nearly impossible. The RWTH team had to extract a cell from a Tesla Model Y themselves. In contrast, BYD’s cells (which use LFP chemistry) are more accessible in China’s open market.

Why does that matter? Because if you can’t even get the cell, you can’t learn its secrets. Real-world engineers sometimes joke that “if you can’t buy it, you can’t study it.” But thanks to the BYD cell, they could make direct comparisons between two wildly different architectures.

Mechanical Layout: Cylindrical vs. Prismatic—Choose Your Fighter

Tesla’s Cylindrical Cells

Format & Packaging: Tesla uses smaller, cylindrical cells (think 2170 form factor), packed into parallel clusters.
Pros: If one cell dies or degrades prematurely, the parallel string design ensures the rest of the module keeps chugging along. Redundancy = reliability.
Cons: More cells mean more “passive component volume.” In plain English, you need more steel or aluminum housings, more tabs, and more welds per unit energy. That adds weight, complexity, and cost.

BYD’s Prismatic Cells

Format & Packaging: BYD sticks with larger, prismatic pouch-style cells. These guys are connected in series.
Pros: Because each cell holds a lot more capacity, you end up with a more compact pack in terms of “materials-to-energy” ratio—fewer housings and welds per kilowatt-hour.
Cons: The serial connection is a single point of failure. If one cell in the string goes bad, you could lose power or require complex bypass electronics. Not ideal if you need rock-solid uptime.

In my world of electric truck chassis design, I’m always crunching the trade-offs between weight, space, and reliability. Smaller, redundant cells give me peace of mind for uptime, but larger cells are more wallet-friendly and pack-dense. If you’re designing a heavy-duty EV meant to haul massive loads day in and day out, you might lean toward the prismatic approach—just make sure your battery management system is bulletproof.

Welding Wizardry: Laser vs. Ultrasonic

One of the cooler bits from the teardown: the RWTH crew discovered that Tesla uses laser welding to fuse extremely thin copper and aluminum tabs. Laser welding copper is notoriously tricky, especially at thicknesses under 100 μm. You’re basically walking a knife’s edge between “fully welded” and “oops, you just vaporized the joint.”

BYD, on the other hand, combines laser and ultrasonic welding. The ultrasonic process (vibration-induced heating) helps compact the tabs before the laser seals the deal. This hybrid approach is more forgiving when you’re dealing with big prismatic cells where mechanical tolerances aren’t quite as tight as micro-scale cylindrical tabs.

For me, as I design mounting brackets and enclosures for an underbody battery tray, understanding these welding approaches is key. If a manufacturer can’t nail down a consistent weld process in a gigafactory, that ripple effect shows up later as hot spots, weld failures, or uneven thermal gradients.

Chemistry Face-Off: LFP vs. NMC811

BYD’s LFP (Lithium Iron Phosphate)

Pros: Super stable, low cost, and chemically robust. LFP doesn’t freak out thermally the way nickel-rich chemistries can. Plus, in high-volume Chinese EVs, range needs are a bit less aggressive—lots of urban commutes and bolted-on fast charging networks.
Cons: Lower energy density. In a heavy-duty EV, that means more cells (or higher pack weight) to hit your range targets. For a 200 km range, you might need a bulkier LFP pack compared to NMC811.

Tesla’s NMC811 (Nickel Manganese Cobalt)

Pros: High energy density—critical if you’re fitting a 300+ kWh pack under an 8×8 electric truck chassis. More kilowatt-hours for a given volume or mass.
Cons: Cost (nickel and cobalt are pricy) and slightly trickier thermal management. Nickel-rich cells can heat up faster under high C-rates, so you need robust cooling loops or passive-thermal tricks (like honeycomb PCM panels) to keep them in check.

For my blog readers—particularly fellow structural and thermal engineers—this is a reminder: chemistry drives the entire pack architecture. If you think you can slap on any cell type and “make it work,” you’ll get burned (literally or figuratively). That’s why I’m super interested in passive thermal management strategies, like embedding phase-change materials in honeycomb panels around NMC cells. It’s a trade-off: you pay a bit more up front for thermal stability and end up with a longer-lasting pack.

The Deep Dive Process: What They Actually Did

Electrical Characterization
- They jammed the full cells into a climate chamber and measured internal resistance at different temps, states-of-charge, and current draw. This is exactly what we do in R&D before finalizing a cell supplier—know how that internal Ohm’s law changes when you push cold-current or high-current pulses.
Argon Environment & Full Discharge
- To safely handle the cells, they brought them to 0% SOC inside an argon-filled glovebox. You never want lithium cells with charge sitting out in the open—fire hazard 101.
Physical Teardown
- Rip it all apart: peel off the outer foil, cut through welds, pry out electrode stacks. Then send those electrode samples off to partner labs (SEM, XRD, ICP, you name it) for composition and microstructure mapping.
Component Weighing & Geometry
- Everything gets measured, weighed, and cataloged: thickness of electrode foils, tab gauges, case housings, insulators, spacers, thermal shims. That dataset helps build digital twins for simulation. If you want to run a crash simulation on a pack, you need accurate dimensions and materials for every layer.
Documentation & Cost Estimation
- After weighing and measuring, they estimated how much raw material each pack used. That feeds back into cost-per-kWh models. If you want to compete in the EV truck space, you NEED to know your $/kWh targets as early as the concept phase.

So, What’s the Big Picture?

Baseline for Future Cell Designs
Now that we have an open-source-ish reference for how Tesla and BYD engineer their cells, anyone in the battery R&D game has a starting point. Before this, there wasn’t much publicly available data on gigafactory-scale manufacturing processes.
Benchmarking Beyond a Single Metric
Jonas Gorsch emphasizes: “You can’t just say, ‘Our battery has 600 km range!’ You gotta compare range, energy density, charge rate, cost, and manufacturability.” It’s the holy-grail of balanced battery design. As designers working on electric truck chassis, we need to account for the fact that a 1% drop in cell energy density might mean an extra 100 kg of batteries—and that 100 kg has to be supported by the frame, axles, suspension, and even brakes.
Regional Preferences Are Real
The teardown shows why Chinese EV makers lean heavily on LFP—it’s cheap, stable, and suits urban use cases where range anxiety isn’t as critical. Meanwhile, Tesla’s NMC811 packs are all about that high-density performance for long-distance markets in the U.S. and Europe. If you’re designing a gigawatt-scale battery plant (like the Fraunhofer gigafactory in Münster), you need to pick the chemistry that aligns with your target region’s use case and price point.
Implications for EV Truck Design
- Thermal Management: If you go NMC811, you need active cooling loops or backup passive systems (like honeycomb PCM). That adds structural complexity: coolant channels, manifolds, pumps. If you go LFP, you might skip active cooling for certain climates, lighten up the pack enclosure, but accept a bigger footprint.
- Crashworthiness: Cylindrical cells will behave differently in an impact than prismatic cells. Cylindrical cells can "concertina" (squish) but often have steel canisters that distribute force more evenly. Prismatic cells are layered pouches—when you compress them, you can get unpredictable delamination or short circuits. Designing the battery cage means knowing which failure modes to guard against.
- Manufacturing Constraints: If you’re building a modular, swappable battery pack for a fleet of tipper trucks, you might prefer LFP prismatic cells—swapping big, fewer cells is easier than grappling with hundreds of tiny cans. But you’ll need robust contactors and BMS redundancy to avoid that “one bad cell kills the pack” nightmare.

Final Thoughts & Next Steps

As electrification goes mainstream, we’ll see bigger push for custom cell formats—think drones, air taxis, or even military EVs. Those end-users will demand specific voltage, size, and energy profiles that could deviate from the standard 2170 or prismatic blocks. That’s why my takeaway (and a big reason I’m hyped to share this teardown intel) is that battery cell design is no longer isolated chemistry-nerd territory. It’s a multidisciplinary puzzle: mechanical design, thermal engineering, production tech, supply chain, cost modeling, safety, and even user behavior.

For my fellow Gen Z engineers stepping into the EV game: dig deeper than press releases. If you can find a way to participate in a teardown or at least get data on existing packs, do it. Your next killer innovation might come from realizing that swapping the welding method or tweaking the tab layout saves you 5 kg per pack and slashes your manufacturing costs. Or maybe you invent a hybrid cooling concept that uses phase-change materials in a honeycomb sandwich—giving your battery pack a self-regulating thermal buffer that’s perfect for heavy-duty trucking.

That’s it for today’s blog! Remember, don’t just chase “bigger numbers” on paper—understand the full lifecycle from raw materials to pack integration into an EV chassis. If you’re designing an electric truck (like yours truly), those nuggets of teardown wisdom can save you countless hours and dollars down the road. Stay curious, stay scrappy, and keep innovating! 💪🔋

References & Further Reading

Agam Shah (ASME Magazine), “EV Battery Secrets Unlocked”
Jonas Gorsch et al., “Manufacturing & Scale Considerations in Tesla vs. BYD Batteries,” Cell Reports Physical Science (March 2025)
Fraunhofer Research Institution for Battery Cell Production, Münster (funded by German government)

Feel free to drop questions or share your own teardown stories in the comments—let’s build that EV future together! 🚚⚡

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