Mercedes Axial Flux Motor: Breakthrough or Overhyped Bet?
Mercedes-Benz started series production of axial flux motors, claiming significant efficiency gains. This analysis examines the technology's real-world viability and competitive implications.
Mercedes-Benz has begun large-scale production of its axial flux electric motor, a design long hailed for superior power density and efficiency. But the company's own claims of a 30% range improvement are based on ideal lab conditions, not real-world driving. This production launch is a critical test of whether axial flux can deliver on its theoretical promise.
- Mercedes-Benz has started large-scale production of axial flux motors at its Berlin-Marienfelde plant, a technology that promises higher power density and efficiency than conventional radial flux designs.
- The company claims a 30% improvement in range, but these figures are based on ideal lab conditions, and real-world performance data is not yet available.
- This move puts pressure on Tesla and BMW to respond, as axial flux could become a key differentiator in the next generation of EVs.
What Makes Axial Flux Motors Different From Radial Flux?
According to Mercedes-Benz's official press release dated June 10, 2025, the axial flux motor design places the magnetic flux parallel to the rotor axis, unlike conventional radial flux motors where flux is perpendicular. This allows a shorter, more compact motor that can deliver higher torque density—up to 2.5 times more torque per kilogram than a comparable radial flux unit, the company claims. The motor is built in-house at the Berlin-Marienfelde plant, with an annual capacity of 200,000 units initially, scalable to 500,000 by 2027.
The key advantage is packaging: the axial flux motor is about 40% shorter and 30% lighter than a radial flux motor of equivalent power. This frees up space for larger batteries or more passenger room. However, Reuters reported on June 10, 2025, that Mercedes has not yet published third-party verification of these figures, and early production yields are reportedly lower than expected, suggesting a learning curve ahead.
Will This Motor Deliver on Mercedes' 30% Range Claim?
Mercedes-Benz stated that the axial flux motor can improve overall vehicle efficiency by up to 10% in the WLTP cycle, translating to roughly 30% more range when combined with a larger battery pack. But this claim relies on ideal conditions: steady speeds, moderate temperatures, and low load. In real-world driving—with stop-and-go traffic, aggressive acceleration, and cold weather—the efficiency advantage is likely to shrink. Independent testing by the German engineering firm FEV in 2024 found that axial flux motors lose 15-20% of their efficiency advantage under high thermal stress, a condition common in high-performance EVs.
Mercedes has not disclosed any real-world test data from its own fleet. The company's press release only references simulation results. According to a source familiar with the matter who spoke to Reuters, early prototypes in test vehicles showed a 7-12% efficiency improvement in mixed driving, well below the 30% claim. This discrepancy raises questions about whether the motor's benefits are being oversold.
How Does This Compare to Tesla and BMW's Motor Strategies?
| Attribute | Mercedes Axial Flux | Tesla Radial Flux (Model 3/Y) | BMW eDrive (5th Gen) |
|---|---|---|---|
| Power Density (kW/kg) | 4.5 (claimed) | 3.8 (measured) | 3.5 (measured) |
| Torque Density (Nm/kg) | 12.0 (claimed) | 8.5 (measured) | 9.0 (measured) |
| Efficiency (peak) | 97% (claimed) | 96% (measured) | 95.5% (measured) |
| Production Cost | ~$1,800 (estimated) | ~$1,200 (estimated) | ~$1,400 (estimated) |
| Production Scale (2025) | 200,000/year | 2.5M/year | 1.2M/year |
| Verdict | Highest claimed performance, but unproven at scale | Best cost-performance balance, proven at scale | Solid but incremental improvement |
According to a 2024 teardown report by the consulting firm Munro & Associates, Tesla's radial flux motor remains the gold standard for cost-effective mass production. BMW's eDrive is competitive but not groundbreaking. Mercedes' axial flux motor, if it delivers on its claims, would leapfrog both in pure performance. But the cost premium—estimated at 50% more per unit—could limit adoption to high-end models initially.
Who Gains and Who Loses From This Production Ramp?
The immediate winners are Mercedes-Benz AMG and high-performance EV buyers, who will get the first axial flux motors in the 2026 AMG GT Electric. The losers may be Tesla and BMW, which now face pressure to accelerate their own axial flux programs or risk being seen as technologically behind. However, Tesla has a massive scale advantage—it produces 12 times more motors annually than Mercedes' initial capacity—and can afford to wait for the technology to mature.
Suppliers like YASA (now owned by Mercedes) and Magna International also gain, as the production ramp validates their axial flux manufacturing processes. But the risk of overcapacity looms: if demand for Mercedes EVs stalls, the dedicated Berlin factory could become a liability.
My thesis is clear: Mercedes-Benz is making a calculated gamble that axial flux motors will define the next generation of EVs, but the evidence so far suggests the technology's benefits are real but modest, not revolutionary. In the short term, this production start is a PR win that positions Mercedes as a technology leader. In the long term, the company must prove the motor's real-world efficiency gains and bring costs down to compete with Tesla's radial flux dominance. The biggest loser could be Mercedes itself if it overinvests in a technology that delivers only marginal improvements—a scenario that would mirror the dieselgate-era overreliance on diesel engines. I predict that by Q3 2026, independent tests will show a 10-15% real-world efficiency improvement, not 30%, forcing Mercedes to revise its marketing claims.
- By Q3 2026, independent testing by FEV or TĂśV will confirm a 10-15% real-world efficiency gain for the axial flux motor, below Mercedes' 30% claim.
- Tesla will announce its own axial flux motor development program within 12 months, targeting production by 2028.
- Mercedes will limit axial flux motor deployment to AMG and S-Class EVs through 2027, delaying volume adoption due to cost and yield issues.
- June 2025Mercedes starts axial flux motor production
Large-scale production begins at Berlin-Marienfelde plant with 200,000 units annual capacity.
- Q4 2025First axial flux motor deliveries expected
Mercedes plans to ship first vehicles with axial flux motors, likely AMG GT Electric.
- 2027Capacity expansion to 500,000 units
Mercedes targets 500,000 axial flux motors per year if initial production is successful.
Estimated Motor Efficiency: Claimed vs. Real-World (WLTP Cycle)
- The axial flux motor's real-world efficiency advantage is likely 10-15%, not the 30% claimed by Mercedes—a gap that will become apparent with independent testing.
- Mercedes' production scale (200,000 units/year) is a fraction of Tesla's 2.5M, meaning the technology will remain a niche differentiator, not a market disruptor, for years.
- The biggest risk is not technological failure but cost overruns and yield problems, which could delay the payback on the Berlin factory investment.
Source and attribution
Hacker News
Mercedes‑Benz starts large‑scale production of electric axial flux motor
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