34.9°C
Peak, SampoVolt edge-cooled
Thermal control. A smaller pack. A longer life.
How can a change to battery pack cooling unlock the highest reduction in fuel per kg?
Packs built to move electricity and heat for next-generation chemistries. Enhance today's chemistry. Enable tomorrow's.
An edge-cooled ribbon stays inside ordinary thermal limits during a fast charge. A series-hybrid SUV delivers the same peak from about half the battery. A pack near 30 kWh can still move the vehicle. The onboard generator stays simple.
Headquartered in Austin, Texas
Public highway statistics
If we are 20 years into the EV revolution, why isn't US fuel consumption dropping more?
Highway fuel leveled off. The gallons sit in the pickups, vans, and SUVs people prefer. An EV has to fit the price, the road trip, the comfort, and the size. Truck SUVs and pickups dominate new light-vehicle production.
For a vehicle that size, a pure battery pack has to be large. You haul that weight every day and rarely use all of it. The weight calls for heavier, more durable parts, and the price moves past most buyers. Building packs that large for so many vehicles also strains the supply chain and often requires more expensive chemistries. Most hybrids do not fix the price either. In a series hybrid the battery alone has to deliver the peak. With conventional cooling, the pack still has to grow large enough that, combined with the engine system, it once again lands at a price few buyers can meet.
Cooling is the bridge. A pack near 29 kWh is light, has the peak power, and stays cool enough for the improved cycle life. Daily driving is electric. The generator covers the road trip. The vehicle stays light enough to be a price a buyer can meet.
The fuel moved into the vehicles people prefer.
US highway fuel climbed for decades, then leveled off. It did not settle into a long decline. From 2007 through 2024, gasoline plus special fuels, mostly diesel, stayed in a band from 159 to 186 billion gallons a year.2 The latest year, 2024, is 171.8 billion. The low year is 2020. The high year is 2022.
The mix changed. Pickups, vans, and sport utility vehicles used 75.9 billion gallons in 2019.3 Cars used 48.6. Many crossovers that count as car SUVs are still inside the car figure, so the utility-vehicle share is at least that large. In model year 2021, the EPA Automotive Trends Report, Table 3.2, puts truck SUVs at 44.7 percent of light-vehicle production, pickups at 16.1 percent, and car SUVs at 11.4 percent.1
Hydrocarbon fuel is a remarkable store of energy. A tank is the right reserve: the long trip, the cold morning, the day without a plug. A small battery can take the everyday miles, if it can deliver the peak, day after day, without cooking itself.
A series-hybrid SUV or pickup asks a small pack for a high rate, through heat and cold, for years. An edge-cooled LFP and graphite ribbon stays inside ordinary temperature limits at that rate. The pack stays near 30 kilowatt-hours instead of growing until the rate falls. A smaller pack is a price a buyer can meet. Cycled hard, each kilogram is aimed at the vehicles that burn the most fuel. The engine and the tank stay for the reserve.
The same cooling opens the vehicle. A pack in the 30 kilowatt-hour range can still move the whole vehicle. That is what a series hybrid needs. The motor takes the launch, the grade, and the pass. The generator starts before a hard pull and shares that load. It can be smaller, steadier, and set up for one efficient job.
US highway fuel has leveled off
Billion gallons. Gasoline, including gasohol, stacked with special fuels. Special fuels are mostly diesel.2
| Year | Gasoline | Special fuels | Total |
|---|---|---|---|
| 2007 | 135.4 | 40.8 | 176.2 |
| 2010 | 133.7 | 36.7 | 170.4 |
| 2015 | 132.4 | 40.5 | 172.9 |
| 2018 | 137.2 | 43.5 | 180.7 |
| 2019 | 136.1 | 43.9 | 180.0 |
| 2020 | 117.3 | 41.9 | 159.2 |
| 2022 | 140.7 | 45.2 | 186.0 |
| 2023 | 131.7 | 45.1 | 176.8 |
| 2024 | 127.3 | 44.5 | 171.8 |
Public highway statistics, not SampoVolt test data.
Pickups, vans, and SUVs passed cars
Billion gallons of fuel used on the road. The copper line is pickups, vans, and sport utility vehicles.3
| Year | Cars | Pickups, vans, and SUVs | Series |
|---|---|---|---|
| 1990 | 69.6 | 35.6 | FHWA published split |
| 2000 | 73.1 | 52.9 | FHWA published split |
| 2008 | 71.5 | 61.2 | FHWA published split |
| 2010 | 62.2 | 64.7 | Oak Ridge estimate |
| 2015 | 55.2 | 70.9 | Oak Ridge estimate |
| 2019 | 48.6 | 75.9 | Oak Ridge estimate |
| 2020 | 40.5 | 68.1 | Oak Ridge estimate |
Public highway statistics, not SampoVolt test data.
Where the 2024 gallons went
Billion gallons by the vehicle classes FHWA still publishes. Light-duty vehicles are the copper bars.4
| Vehicle class | What it includes | Billion gallons |
|---|---|---|
| Light-duty, short wheelbase | Cars, and smaller crossovers, SUVs, and vans | 86.9 |
| Light-duty, long wheelbase | Larger SUVs, pickups, and vans | 37.9 |
| Combination trucks | Highway freight, mostly diesel | 27.1 |
| Single-unit trucks | Heavier straight trucks | 17.0 |
| Buses | Transit and other buses | 2.4 |
| Motorcycles | Two- and three-wheel | 0.5 |
Public highway statistics, not SampoVolt test data.
Why series hybrids stayed large
The battery has to carry the peak alone.
In a series hybrid, the engine does not turn the wheels. The motor does. The battery feeds that motor at full power. A right-sized pack lives at a high C-rate: a lot of power from not very many kilowatt-hours.
A traditional face-cooled prismatic cell runs out of thermal room near 2.7C. To deliver the same peak, the pack grows until the rate falls back inside the limits. More battery. More mass. Less fuel saved per kilogram.
We design from the pack in, not from a coin cell out. The change is the cooling path.
The comparison
Cooler and more even during fast charge.
SampoVolt builds stacked ribbon electrodes. On edge, heat leaves along the metal. Packed appropriately, the stack is a low-resistance heat exchanger. Same LFP/graphite cell. Same coolant. Only the cooling path changes.
At a 5C charge
47.4°C
Peak, Typical face-cooled
4.7K
Spread, SampoVolt edge-cooled
16.6K
Spread, Typical face-cooled
Peak cell temperature during fast charge
Degrees Celsius. Same cell, same coolant, two cooling paths.
| Charge | SampoVolt edge-cooled | Typical face-cooled |
|---|---|---|
| 2C | 30.8 | 32.8 |
| 3C | 31.7 | 36.3 |
| 5C | 34.9 | 47.4 |
Modeled, not test data. Same LFP/graphite cell (2.5 mAh/cm²), same coolant, only the cooling path differs.
Temperature difference inside the cell
Kelvin, hottest point minus the coolest electrode.
| Charge | SampoVolt edge-cooled | Typical face-cooled |
|---|---|---|
| 2C | 0.8 K | 2.7 K |
| 3C | 1.7 K | 6 K |
| 5C | 4.7 K | 16.6 K |
Modeled, not test data.
A small pack can take a hard burst
Even at a 7C demand, the temperature spread inside the cell stays near 2.5 K after 10 seconds, about half our 5 K limit, so a merge or a pass never gets close. It rarely has to, either: the controller starts the engine before the climb or the hard pull, and tow mode keeps the engine on, so the 70 kW generator and the battery share the load and the pack settles at about 4.6C, inside its limits for as long as you hold the pedal.
Modeled, not test data.
The limits are a 5 K spread inside the cell and a 45 °C peak. The edge-cooled ribbon holds 5.15C indefinitely. On a 150 kW SUV, that is the 29 kWh pack. The face-cooled prismatic holds to 2.74C. About 5C, against about 2.7C. That is the room a series hybrid was missing.
The pack is designed for well-known industrial technology.
SampoVolt builds on the rolled-ribbon electrode invented by Thomas D. Kaun and developed at InvenTek (US Patent 7,195,840, now expired), with research support from Argonne National Laboratory.5 Not affiliated with the inventor or Rolled-Ribbon Battery Company.
Same power, about half the battery
A 60 to 70 mile hybrid SUV. The right size.
For an SUV at a 150 kW peak, the edge-cooled pack is 29.2 kWh and 249 kg. The face-cooled pack for the same peak is 55.6 kWh and 436 kg. About half the battery.
That is a practical 60 to 70 mile series hybrid. At that sweet spot, about 33 lifetime gallons of fuel are displaced per kilogram of battery, against about 19 for the larger face-cooled pack. Over a year, about 2.2 gallons per kilogram against about 1.3.
At a cell price of $55 to $95 per kWh, the cells are $1,609 to $2,779, against $3,057 to $5,280. About half the cell cost. A price buyers can reach. Cell cost only. Pack and vehicle are not in those figures.
What that power changes
The pack moves the vehicle. The generator can be simpler.
The pack
Near 30 kWh, still the peak
29.2 kWh supplies a 150 kW peak for an SUV. That is about 5C, and the edge-cooled pack holds it for as long as you need that rate. The face-cooled pack needs 55.6 kWh for the same peak.
The vehicle
A series hybrid
The engine does not turn the wheels. The motor does, and this pack can feed that motor. Everyday miles come off the battery. The tank stays the reserve.
The generator
Sized for energy, not the launch
Before a climb or a hard pull, it starts early and shares the load. Tow mode leaves it on. It can still be smaller than the peak and held near one efficient point. The engine makes electricity. It does not need a transmission to the wheels.
Same power, about half the battery
To deliver the same peak power without overheating, a conventionally cooled pack has to be roughly twice as big.
SUV
about 1.9× smaller
SampoVolt edge-cooled29 kWh
Typical face-cooled56 kWh
249 kg against 436 kg
Pickup
about 1.9× smaller
SampoVolt edge-cooled50 kWh
Typical face-cooled94 kWh
Van
about 1.9× smaller
SampoVolt edge-cooled29 kWh
Typical face-cooled56 kWh
| Vehicle | SampoVolt edge-cooled | Typical face-cooled |
|---|---|---|
| SUV | 29 kWh, 249 kg | 56 kWh, 436 kg |
| Pickup | 50 kWh | 94 kWh |
| Van | 29 kWh | 56 kWh |
Modeled, not test data. About 1.9× is the face-cooled kilowatt-hour label divided by the edge-cooled label: 56/29 for the SUV and the van, 94/50 for the pickup. Peak rates in the model: SUV 5.1C against 2.7C, pickup 5.0C against 2.7C, van 5.1C against 2.7C. Limits are a 5 K spread inside the cell and a 45 °C peak. SUV weight is the same comparison at full precision: 29.2 kWh and 249 kg, against 55.6 kWh and 436 kg, at a 150 kW peak.
Lifetime gallons displaced per kilogram
Series-hybrid SUV. Sweet spot at 60 to 70 miles.
| Electric range | SampoVolt edge-cooled | Typical face-cooled |
|---|---|---|
| 40 mi | 31.7 | 18.1 |
| 50 mi | 32.4 | 18.5 |
| 60 mi | 33.0 | 18.9 |
| 70 mi | 33.4 | 19.1 |
| 80 mi | 31.3 | 19.4 |
Modeled, not test data. At 80 miles the edge-cooled pack is 32.2 kWh and 271 kg.
The pitch: thermal control that lets a small pack take harsh, high-power cycling day after day and still last.
Crawl, walk, run, fly
Fuel savings first. Harder chemistry later.
Prove the ribbon on known LFP and graphite, where a series hybrid saves the most fuel. Scale fleets and fast charge. Then raise the chemistry. Flight is the horizon, a future vision.
One ribbon pack. Chemistry comes in steps.
Reduce technology risk while going after US fuel savings first. Fly is a future vision.
- CrawlLFP / graphite
Series-hybrid SUVs and pickups
- Prove the ribbon geometry on a chemistry the industry already knows.
- The largest US fuel-savings opportunity, at lower technology risk.
- A supply chain that can ramp before the materials get harder.
Next: show the cooling difference on LFP and graphite.
- WalkLFP / graphite
Hybrid and work-van fleets, and fast charge
- Scale the proven geometry into vans and other working fleets.
- A van meets a 150 kW peak with about 29 kWh, against 56 kWh face-cooled.
- Fast charge stays the job the cooling was built to do.
Next: fleets, still inside the same thermal limits.
- RunLMR / silicon
Heavy semis and pure battery cars
- LMR and silicon, for example SCC55, once the geometry has earned the right.
- Heavy semis, where fast charge and mass both count.
- Pure battery cars after the hybrid proof, not before it.
Next: higher-energy chemistry on a pack the cooling already fits.
- FlyLithium-sulfur
Future vision
- Electric and hybrid-electric aviation, as the technology scales.
- The chemistry path is lithium-sulfur and sulfur-silicon.
- A direction for the platform. Not an aircraft program.
Future vision. No aircraft specification is stated here.
One edge-cooled ribbon pack under every step
- ThermalCooler, and more even, inside ordinary limits. Modeled, not test data.
- Fast chargeThe cooling path is what makes the higher rate fit.
- OrderKnown chemistry first. Harder chemistry, then flight, after that.
Where the pack goes
Enhance today's chemistry. Enable tomorrow's.
The same pack can make a current chemistry last longer and charge faster in the same footprint. It can be redrawn when the material changes. Gravimetric questions and volumetric questions are not the same job. These are program directions, not products for sale.
Devices
Consumer electronics
The score is volumetric energy density, fast charge, and cycle life. Phones make that constraint absolute. Robotics is the same problem: the volume is already claimed by the machine. We design the volumetric cell for both.
Vehicles
Automotive
Cost, cycle life, charge speed, and gravimetric density. Trucks and SUVs first. Class 8 is how a supply chain gets large enough to matter.
In-house
Light mobility
Our own packs for e-bikes and scooters, where a chemistry can be learned in hardware we control.
Future vision
Aviation
Electric and hybrid-electric flight, after the technology scales. Lithium-sulfur and sulfur-silicon are the chemistry path. A horizon, not a program, a specification, or a date.
Safety by design
Safety is built into the pack, not added on.
Heat, gas, and force get a place to go before anyone claims a charge rate or a life. Propagation resistance, battery management, and abuse design stay in the pack. The vent and the thermal path sit on that foundation.
Gas leaves on its own path
Every cell vents through its own one-way path into sealed galleries, clear of the pack air and the electrical connections. LMR, and any chemistry that gasses, is designed with that path from the start.
A hot spot is a safety problem
Aging and the start of abuse collect where a cell runs hot. A short thermal path keeps the layers closer. Uniformity is a safety property.
The hazard follows the chemistry
LMR can gas from both electrodes during formation and is the most temperature-sensitive for cycle life. Some chemistries need more stack pressure. Silicon swells, or plates if pushed cold. Sulfur and Lithium-air bring their own constraints. Tight temperature control can enable thicker electrodes, higher load rates, and low-cost polymer electrolytes such as PEO or PVDF-HFP. The pack is specified for the one in front of us.
Contact
If you have a pack you need, write.
Learn more if you are interested in either of these.
Heat
Extreme thermal control
A pack that needs extreme thermal control to enable fast charging or extend cycle life.
Pressure
Pressure on the cells
A pack that can apply pressure to the cells.
info@sampovolt.com
Headquartered in Austin, Texas
Bring the chemistry, the footprint, and the duty. Electrochemical or electromechanical, that is enough to start. Vehicle and device makers, cell makers, researchers, strategic partners, and aligned investors.
Modeled, not test data. Temperatures, pack sizes, cell cost, and gallons displaced per kilogram are model results. Improved cycle life is the design goal from holding the cell evenly. It is not a measured result, and this is not a measured charge time or a measured cycle life. No engine is selected, and no vehicle has been measured. Public highway statistics are not SampoVolt test data.
Sources
The numbers you can open.
- U.S. EPA, Automotive Trends Report, EPA-420-R-22-029, December 2022, Table 3.2. Model year 2021 light-vehicle production shares: truck SUVs 44.7 percent, pickups 16.1 percent, car SUVs 11.4 percent.https://www.epa.gov/system/files/documents/2022-12/420r22029.pdf
- Federal Highway Administration, Highway Statistics, Table MF-27. Gasoline, including gasohol, and special fuels, mostly diesel. The 2024 table is the latest year on the chart, 171.8 billion gallons. Earlier years are this table in prior Highway Statistics editions. A stacked bar can differ by 0.1 from the printed total because each figure is rounded.https://www.fhwa.dot.gov/policyinformation/statistics/2024/mf27.cfm
- Oak Ridge National Laboratory, Transportation Energy Data Book, Edition 40, Tables 4.1 and 4.2, June 2022 update. Through 2008 the split is the Federal Highway Administration series for cars and for two-axle, four-tire trucks: pickups, vans, and sport utility vehicles. FHWA stopped publishing that split after 2008. Later years are the Oak Ridge continuation and are not comparable with the earlier points. In 2019 the estimate is 75.9 billion gallons for pickups, vans, and SUVs, against 48.6 for cars. Many crossovers that EPA counts as car SUVs stay inside the car number.https://tedb.ornl.gov/wp-content/uploads/2022/03/TEDB_Ed_40.pdf
- Federal Highway Administration, Highway Statistics 2024, Table VM-1. Short wheelbase means 121 inches or less and mixes passenger cars with smaller crossovers, SUVs, and vans. Long wheelbase is the larger SUVs, pickups, and vans. Light-duty vehicles are 124.8 billion of the 171.8 billion gallon total. FHWA does not publish a separate crossover line.https://www.fhwa.dot.gov/policyinformation/statistics/2024/vm1.cfm
- Thomas D. Kaun, US Patent 7,195,840, rolled-ribbon cell structure. Now expired.https://image-ppubs.uspto.gov/dirsearch-public/print/downloadPdf/7195840