Skip to content 
TTesla’s 4680 battery pack represents a pivotal leap in EV architecture, performance, and manufacturing economics. At Munro & Associates, we’ve dissected both the older 2170 cell design and the newer 4680 format to uncover how Tesla continues pushing the boundaries of lean automotive design. In this post, we explore the design rationale, electrical configuration, and structural innovations embedded in Tesla’s next-gen energy platform—and why it matters for engineers, enthusiasts, and investors alike.
From 2170 to 4680: A Shift in Philosophy
Historically, Tesla relied on 2170 cells for models like the Model 3 and the original Model Y. With roughly 4,460 of these smaller cylindrical cells used per vehicle, engineers faced challenges in managing thermal load, wiring complexity, and structural inefficiencies. Enter the 4680 cell—a wider, taller format designed not just for energy density, but for simplification and scalability.
The 4680’s specs speak volumes:
- 6× power output
- 5× energy capacity
- 16% increase in vehicle range
- ~50% reduction in pack cost
This transformation is not merely a manufacturing upgrade. It’s a holistic redesign that aligns with Munro’s core philosophy: superior product design solves more problems than manufacturing tweaks alone.
Why Design Trumps Manufacturing in Battery Evolution
Tesla’s battery innovation doesn’t come from incremental changes to legacy production. Instead, they reengineered the battery pack from the ground up. Attempting to retrofit the older 2170-based packs would never yield the performance or cost advantages Tesla now achieves. The new system integrates structural considerations, power efficiency, and serviceability into one modular approach.
Tesla’s new pack comprises 960 4680 cells—significantly fewer than the older cell count, yet more capable due to improved energy density and connection strategy. These cells are grouped in a matrix of four modules per pack, with 96 groups of 10 cells—structured to deliver around 336 volts nominal.
Understanding Series vs. Parallel Battery Architecture
Battery packs are complex, but at their core, the principles of electrical engineering apply. Tesla’s configuration involves both series and parallel connections. The concept is straightforward:
- Series Connection: Increases voltage by connecting positive to negative ends. Like stacking AA batteries in a flashlight.
- Parallel Connection: Increases current capacity by connecting all positives and all negatives together.
Tesla’s design cleverly applies these principles to balance voltage, current, and thermal performance. For each module:
- Ten cells are grouped together in parallel.
- Ninety-six such groups are connected in series.
- Result: 96 × 3.5V = ~336V total pack voltage.
This daisy-chain configuration is engineered for simplicity and reliability—a hallmark of Tesla’s innovation ethos.
The Collector Manifold: Mechanical & Electrical Integration
Where earlier designs used thin wires for cell interconnections, the 4680 pack introduces spot-welded collector tabs—akin to a manifold structure. Think of it like an ICE engine’s cylinder head gasket, where each interface is carefully controlled for insulation, pressure sealing, and connectivity.
Here’s the layered setup:
- D1: Outer Insulator Ring – Encases the battery top and prevents arcing or leakage.
- D2: Negative Collector Plate – Smaller in diameter, this plate spot-welds to the battery’s shell (negative terminal).
- Insulating Layer – Separates the negative from the positive collector.
- Positive Collector (with Tab) – Spot-welded to the center terminal of the battery cell.
This modular design standardizes connections, reduces resistance, and eliminates wiring mess. It also supports automated assembly—critical for scaling production at Gigafactories.
How the Pack Feeds the Powertrain
The redesigned pack seamlessly interfaces with Tesla’s power electronics. As the series-parallel array feeds current through designated collector paths, the power exits the pack via designated positive and negative bus terminals. These connect directly to the inverter and electronics bay, powering the vehicle with minimized transmission loss.
Tesla’s design ensures:
- Efficient current flow
- Predictable thermal distribution
- Minimal parasitic draw from excessive wiring or resistance
This is lean electrical engineering at its best.
Structural Integration and Cost Savings
The 4680 pack does more than store energy. It acts as a load-bearing member within the vehicle chassis. By eliminating redundant structural frames, Tesla achieves:
- Lower overall vehicle weight
- Increased torsional rigidity
- Reduced materials and labor cost
In past teardowns, Munro’s team showed how Tesla mounts seats and center consoles directly onto the battery pack. That integration now continues in the 4680 format, blending structural and energy systems into a single component.
Why It Matters: Implications for the Industry
Tesla’s move to the 4680 is not just an incremental upgrade—it’s a systemic disruption. This battery design strategy:
- Increases range and reduces cost
- Enables faster vehicle production
- Simplifies servicing and part replacement
- Aligns with future goals for recycling and sustainability
This means studying pack-level architecture, thermal management, and manufacturability—not just chemistry. It also signals Tesla’s cost leadership and margin durability in a highly competitive EV landscape. And for EV enthusiasts of all stripes—including engineers and investors alike—it’s a preview of what’s coming in mass-market electric vehicles: more power, less complexity.
Final Thoughts from the Teardown Bench
While not every internal feature is publicly confirmed, Munro’s teardown-informed hypothesis reflects real-world engineering logic. Yes, some connection details may vary, and Tesla’s design may evolve. But the principles remain: simplified architecture, parallel manufacturing, and structural efficiency.
As Sandy Munro humorously concludes, “This isn’t a giant mystery. It’s just better design.”
If you’re trying to understand the future of electric vehicles, look no further than the structure beneath the floor. The 4680 pack isn’t just powering the next generation—it’s redefining how EVs are built.
Explore More with Munro
Stay tuned for our upcoming deep-dives into Tesla’s thermal management, inverter design, and Gigacasting strategy. Subscribe to Munro Live on YouTube or visit our site for exclusive teardown reports and lean design consulting services.
Let us know which EV teardown you want next. We’re always listening—and always learning.