One path
Current and heat leave the same short way.
The current collector that carries electricity out of each electrode also carries its heat. Both have a short trip to the edge instead of a long one across the cell.
SampoVolt · Austin, Texas
Cool the cell. Keep the chemistry cheap.
Most battery programs chase energy density with harder, costlier materials. We changed the cooling instead. A pack that gives every electrode a short way out for both electricity and heat lets low-cost, well-known LFP and graphite deliver nearly twice the continuous power from each kilowatt-hour.
Put that pack in the pickups, vans, and SUVs people actually drive, with fuel held in reserve for the long trip, and it takes about half the battery. Each kilogram saves more fuel than it would in a pack designed for energy density.
Explainer
See how it works
The problem
Heat, not energy, sets the size of a hard-working pack.
A pack asked for a lot of power from not many kilowatt-hours runs at a high C-rate. High rates make heat, and heat ages cells. That is the daily job of a battery in a series hybrid, where the motor turns the wheels and the battery alone feeds its peak.
The conventional pack is built around energy density: large flat prismatic cells, packed tight, cooled through their broad faces. Heat has to cross the whole cell to get out, so the middle runs hotter than the outside, and those cells run out of thermal room near 2.7C. So the pack grows, not because it needs the energy but because it needs somewhere to put the heat, or it moves to costlier power-specialty cells. Either way the battery gets bigger or more expensive than the job requires.
The cooling
A short way out for electricity and heat.
SampoVolt builds stacked ribbon electrodes: long, narrow electrodes stood on edge. The current collector, the metal foil inside every electrode, is designed as the way out for both the current and the heat, and it runs the short way to the edge. Packed appropriately, the stack behaves like a heat exchanger. Same LFP and graphite. Same coolant. Only the path changes.
Inside a 45 °C peak and a 5 K spread across the cell, the ribbon holds about 5C indefinitely. The cell also stays cooler and more even, which is the basis of our cycle-life goal. For a 150 kW SUV that is a 29.2 kWh, 249 kg pack. The conventional pack for the same peak is 55.6 kWh and 436 kg. We design from the pack in, not from a coin cell out.
Modeled, not test data. The pack is designed around well-known industrial processes.
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.
Shared plates
No electrode is far from a cooling plate.
Cooling plates are shared between neighboring layers of cells, and the stack is laid out so every electrode sits within a short reach of one. Nothing is buried in the middle.
Even, not just cool
The whole cell runs at nearly one temperature.
Under hard use the pack stays cool, and the spread inside each cell and from one electrode to the next stays small. At a 5C fast charge the modeled in-cell spread is 4.7 K, against 16.6 K for a typical face-cooled cell.
Why even matters
One hot spot ages the whole pack.
A pack is only as good as its weakest cell, and a cell is only as good as its hottest electrode. Where one spot runs hot, it ages first and drags everything wired to it down with it. A pack where every electrode runs at nearly the same temperature is designed to age at the same rate everywhere, so no single hot spot sets its life. Longer pack life is the design goal; it is not yet a measured result.
The chemistry
When cooling carries the rate, low-cost LFP and graphite are enough.
Denser powders, nickel-rich cathodes, and power-specialty cells are how a pack buys energy or rate it cannot cool. Ours does not need to. In our model, moving from an older mainstream LFP powder to the densest pilot grade changes the hybrid pack by about 4 kg. Changing the cooling path changes it by 140 to 160 kg.
So the first packs use the best-known pair in the industry: LFP and graphite in a conventional liquid electrolyte, with a long track record in cars and grid storage. The chemistry is not the open question.
Where the materials are made is. Today more than 90 percent of LFP cathode and graphite anode comes from China.6 US and allied plants are starting to come online, but they are small, and most will not reach volume until late in the decade.
A small pack fits that. Half the battery per vehicle means half the cells to buy: cell cost for the SUV pack comes to roughly half, and the same early US output fills about twice as many vehicles. It also shrinks the cost of buying American. Whatever premium US-made material carries, a pack half the size pays it on half the kilowatt-hours, for the same vehicle and the same miles.
What it makes possible
Half the battery, and more fuel saved per kilogram.
Build that pack into a series hybrid. The battery takes the daily miles and every peak. A small generator and a tank of fuel cover the long trip, the trailer, and the day without a plug. Every kilogram of battery works nearly every day instead of riding along as reserve.
In a 60 to 70 mile series-hybrid SUV, each kilogram of our pack displaces about 33 gallons of fuel over its life. The conventionally cooled pack, sized for the same peak, manages about 19.
Why hybrid trucks and SUVs cost so much
Today's hybrids oversize both the engine and the pack.
In a conventional hybrid the engine still drives the wheels, so it keeps a full transmission and has to be big enough for the launch and the tow. The battery grows too, because conventionally cooled cells cannot deliver high power from a small pack. You pay for two power sources, both sized for the peak, and the vehicle ends up priced out of reach.
A pack that handles a higher C-rate changes that. It stays small and still covers the peak, so the engine only has to make electricity. In a series hybrid it can be designed for efficiency at steady, predictable speeds, and because it never turns the wheels, the transmission and the mechanical drive to the wheels come out.
- The coolingPower from few kilowatt-hours.
Heat leaves along the edge, so a small pack can deliver the peak and stay even enough to last.
- The chemistryLow cost, already known.
LFP and graphite in a conventional liquid electrolyte. No premium powder and no specialty power cell.
- The reserveFuel does what it does best.
Hydrocarbons store energy cheaply for the long trip. The generator makes electricity near one efficient point and never turns the wheels.
Lifetime gallons displaced per kilogram
Fuel saved over the battery's life, divided by its weight, for a series-hybrid SUV at each daily electric range. Higher means each kilogram you carry saves more fuel.
| 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. Past the 60 to 70 mile sweet spot the pack grows faster than the miles it covers, so each kilogram saves less fuel. At 80 miles the edge-cooled pack is 32.2 kWh and 271 kg.
Same power, about half the battery
Battery each vehicle needs to deliver the same peak power without overheating, in kilowatt-hours. The pickup bars are sized for a continuous full-power pull; the 43.9 kWh pickup pack we are designing shares that pull with the generator.
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. Design limits are a 45 °C peak and a 5 K spread inside the cell. Rates in the model: about 5C edge-cooled against 2.7C face-cooled for every vehicle. SUV at a 150 kW peak: 29.2 kWh and 249 kg, against 55.6 kWh and 436 kg.
The pitch: thermal control that lets a small pack take harsh, high-power cycling day after day and still last.
Where the fuel goes
The gallons are in the vehicles everyone drives.
Twenty years into electric cars, US highway fuel has leveled off, not fallen. It was 171.8 billion gallons in 2024.2 Pickups, vans, and SUVs passed cars years ago: 75.9 billion gallons against 48.6 in 2019.3And they are what people buy. In model year 2021, truck SUVs were 44.7 percent of light-vehicle production, pickups 16.1 percent, and car SUVs 11.4 percent (EPA Automotive Trends Report, Table 3.2).1
A pure battery big enough for those vehicles gets heavy and expensive. A small, well-cooled battery on low-cost chemistry, with a tank behind it, does not.
Pickups, vans, and SUVs passed cars
Highway fuel used each year, billion gallons.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.
For engineers: temperatures, bursts, and the pickup pack
All figures in this section are modeled, not test data. Same LFP/graphite cell and coolant throughout; only the cooling path differs.
At a 5C fast charge
34.9°C
Peak, SampoVolt edge-cooled
47.4°C
Peak, Typical face-cooled
4.7K
Spread, SampoVolt edge-cooled
16.6K
Spread, Typical face-cooled
Design limits are a 45 °C peak and a 5 K spread inside the cell. The edge-cooled ribbon holds 5.15C indefinitely; the face-cooled prismatic holds to 2.74C. We do not claim a higher continuous rating on the battery alone. For a long climb or a tow, the generator starts before a hard pull and shares that load.
A small pack can take a hard burst
Temperature spread inside the cell over one minute of hard pull. A short burst at 7C stays near 2.5 K after 10 seconds, so a merge or a pass never gets close to the 5 K limit. Hold 7C on the battery alone and the spread crosses that line, so we do not rate it. For a sustained pull, tow mode keeps the engine on: 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 pickup pack we are designing stores 43.9 kWh in 15 modules and weighs about 355 kg. A continuous full-power pull would need nearer 50 kWh on the battery alone, so on the pickup the generator shares that pull.
The essays
The whole argument, with the numbers.
One cell, two markets
Factories built to make electric-vehicle cells are now making cells for grid storage too. SampoVolt plans to work the same way from day one.
The rocket equation comes for the pickup truck
A battery weighs the same full as empty. Why a small pack and a light tank of fuel beat a huge pack in SUVs and pickups, if the pack can take the power.
Power and cycle life save more fuel than a bigger pack
How better cooling lets low-cost LFP and graphite carry the power, and why that small pack saves more fuel per kilogram in the vehicles people drive.
The battery powder China can switch off
A pack sized by power and heat does not need the densest LFP. About 4 kg from the powder, 140 to 160 kg from the cooling.
Crawl, walk, run, fly
Prove it on cheap chemistry. Then raise the chemistry.
Start where a series hybrid saves the most fuel, on the best-known chemistry and the fewest cells per vehicle. Scale into fleets and fast charge. Bring in higher-energy chemistry once the pack has earned it. Flight is a future vision.
One cooling idea. Chemistry comes in steps.
Fuel savings first, technology risk last. Fly is a future vision.
- CrawlLFP / graphite
Series-hybrid SUVs and pickups
- Prove the ribbon on the cheapest, best-known chemistry there is.
- Start where a series hybrid saves the most US fuel.
- Half the cells per vehicle, so early US material output goes twice as far.
Next: show the cooling difference in hardware.
- WalkLFP / graphite
Hybrid and work-van fleets, and fast charge
- Scale into vans and other fleets that drive all day.
- About half the pack of a conventionally cooled van, for the same peak.
- Fast charge is the job the cooling was built for.
Next: fleets, inside the same heat limits.
- RunLMR / silicon
Class 8 trucks and pure battery cars
- Higher-energy LMR cathodes and silicon-carbon anodes such as SCC55, once the pack has earned them.
- Class 8 trucks, where fast charge and weight both count.
- Pure battery cars after the hybrid proof, not before.
Next: harder chemistry in 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, 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 lets the higher rate fit.
- OrderKnown chemistry first. Harder chemistry, then flight, after that.
After the hybrids
Next goal: Class 8 trucking.
Once the ribbon is proven on hybrids, the next goal is the heaviest highway trucks. Tractor-trailers burned 27.1 billion gallons of highway fuel in 2024, mostly diesel.4 They need what edge cooling does best: fast charge without overheating the cells, and long life under hard daily cycling. Every kilogram of battery a truck carries is payload it cannot haul, so a pack that does more per kilogram matters even more here.
Beyond hybrids
Packs built to move electricity and heat.
The same control over heat and pressure that lets LFP work this hard is what next-generation chemistries need. Enhance today's chemistry. Enable tomorrow's.
Vehicles
Automotive
Hybrid trucks and SUVs first, then fleets and Class 8 trucks. Silicon anodes and LMR, a lithium- and manganese-rich cathode, raise energy per kilogram once the pack can hold them evenly.
Devices
Consumer electronics and robotics
Here the space is already claimed by the product, so the score is volumetric energy density, fast charge, and cycle life.
In-house
Light mobility
Our own small packs, where a new chemistry can be learned in hardware we control.
Future vision
Aviation
Electric and hybrid-electric flight on lithium-sulfur and sulfur-silicon chemistries, after the technology scales. A horizon, not a program.
Safety by design
Heat, gas, and force each get a path out.
A cell that runs evenly ages evenly, and a hot spot is where trouble starts. The pack is laid out so a fault in one cell does not spread, and so every cell vents through its own one-way path, clear of the pack air and the electrical connections.
Uniform is safe
Aging and the start of abuse collect where a cell runs hot. A short heat path keeps every layer close to the same temperature.
Gas has a place to go
Chemistries that gas, such as LMR during formation, are designed with that vent path from the start.
The pack follows the chemistry
Silicon swells. Sulfur and Lithium-air bring their own limits. Some chemistries need stack pressure, and tight temperature control opens low-cost polymer electrolytes. Each pack is specified for the chemistry inside it.
Contact
Have a pack that is limited by heat? Write.
Fast charge you cannot cool, cycle life lost to hot spots, a chemistry that needs pressure on the cells. Bring the chemistry, the footprint, and the duty cycle. That is enough to start.
info@sampovolt.comHeadquartered in Austin, Texas
About these numbers: temperatures, pack sizes, cell cost, and gallons displaced per kilogram are model results, not test data. Improved cycle life is the design goal from holding the cell evenly. It is not a measured result, and no charge time or cycle life on this page is measured. No engine is selected, and no vehicle has been built. Public highway statistics are cited below and are not SampoVolt test data.
Sources
Public data behind the fuel numbers.
- 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
- International Energy Agency, Global Critical Minerals Outlook 2025. China's share of LFP cathode material and of battery-grade anode graphite production is above 90 percent; LFP cathode is reported above 98 percent for 2024.https://www.iea.org/reports/global-critical-minerals-outlook-2025