Badger wrote: ↑01 May 2026, 09:08
gruntguru wrote: ↑01 May 2026, 07:56
Badger wrote: ↑28 Apr 2026, 09:14
SSBs have been "expected" for ages, issues constantly come up. We just had that Donut Labs hoax which is typical of the battery industry. Battery chemistry is not magic, it's a compromise between forces that are working against each other. So when you need ultra-high density, high discharge rate, limited cooling, rapid cycling, and a decent lifespan, you are asking for a unicorn product with zero compromises that may never exist, nevermind a few years from now.
https://i.imgur.com/YO9I4yr.png
So if we had 250 Wh/kg batteries 10 years ago, and we had 500 Wh/kg batteries 3 years ago, why is the gravimetric energy density of Formula E batteries only around 165 Wh/kg? Why is the new Gen 4 FE battery only around 160 Wh/kg? Are they stupid? Backwards? They didn’t find the right phone number in the yellow pages? They wanted their cars to be extra heavy and energy constrained?
The problem is you guys throw out numbers with no understanding of the other factors at play. Was it a single cell lab test? What’s the C rate? Did it degrade after 100 cycles? Swelling? Cooling requirements? What’s the fire hazard in case of a crash?
We are talking about a high performance race car here, all these factors matter and the demands are different than for a home appliance. There’s a reason why FE has relatively low energy density in their battery packs and it’s not because they are idiots.
Here is your answer from AI.
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The seemingly low energy density of Formula E batteries (roughly 135–140 Wh/kg for the Gen3 pack) is a deliberate engineering trade-off. Unlike a road car battery, which is designed for maximum energy density (how much energy it can store), a Formula E battery is optimized for extreme power density (how fast it can dump and take in energy).
1. Power vs. Energy Trade-off. Battery design is a "zero-sum" game between range and performance.
Road Cars: Prioritize range. They use "energy cells" that store a lot of power but can only release it slowly without overheating.
Formula E: Prioritize throughput. A Formula E car must discharge up to 350 kW of power instantly and, more importantly, absorb up to 600 kW during regenerative braking.
The Result: To handle these "violent" bursts of energy without exploding or melting, the internal chemistry and physical structure (thicker current collectors, robust cooling) must be much heavier than a standard cell.
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2. Extreme Thermal Management. Charging and discharging at 600 kW generates massive amounts of heat. Formula E batteries require complex liquid cooling systems integrated directly into the pack to keep the cells within a narrow temperature window. This cooling hardware adds significant dead weight that doesn't store energy, dragging down the overall Wh/kg of the total pack.
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3. Reliability and Durability. Formula E batteries are standardized components (currently supplied by WAE) that must survive an entire season of high-speed racing and vibration. Safety Over Speed: They use specialized NMC (Nickel Manganese Cobalt) chemistries that are more stable under racing stress but slightly less dense than the "bleeding-edge" chemistries used in prototypes that only need to last one lap. Cycle Life: Unlike an F1 battery, which is tiny (1.1 kWh) and can be replaced frequently, these packs are meant to be robust enough to maintain performance across multiple E-Prix events.
4. Comparison to Other EVs.
Vehicle Type. . . . . . . . . Approx Energy Density (Pack Level). . . . . . Primary Goal
Tesla Model 3. . . . . . . . 160–170 Wh/kgLong . . . . . . . . . . . . . . . . Highway Range
Formula E Gen3. . . . . . .135–140 Wh/kg. . . . . . . . . . . . . . . . . . . .600 kW Power Throughput
F1 Hybrid Battery. . . . . .35–50 Wh/kg (Estimated). . . . . . . . . . . . . Immediate Burst (Energy is secondary)