Deeptech for the energy transition

Rebuilding the grid battery from the cell up.

BTTRY is developing a modular battery in which every cell is switched individually and the power electronics are built into the battery itself. Designed for sodium-ion and LFP cells, and for a grid that runs on sun and wind.

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Grid-synchronised lab prototype (2026)
Sodium-ion and LFP
Built in the Netherlands

The energy transition has become a storage challenge.

Europe is adding solar and wind faster than ever, but the grid cannot absorb it when the sun shines. Midday prices collapse, often below zero, parks are switched off, and the evening peak is still covered by gas. Storage turns that clean surplus into power when it is needed.

Solar production
Electricity price
Battery charges: low or negative prices
Battery delivers: evening peak

Illustrative summer day, not actual market data.

Europe

of battery storage in the EU by the end of 2025, up from 7.8 GWh in 2021: 77 GWh; Source: SolarPower Europe, EU Battery Storage Market Review 2025
growth in new EU battery storage in 2025: a record 27.1 GWh installed in one year: +45%; Source: SolarPower Europe, EU Battery Storage Market Review 2025
of battery storage the EU needs by 2030: almost ten times today’s fleet: ~750 GWh; Source: SolarPower Europe, EU Battery Storage Market Review 2025

The Netherlands

hours with negative day-ahead electricity prices in the Netherlands in 2025, up from 316 in 2023: 581; Source: RVO, Monitor Zon-PV 2026
of a typical solar park’s potential output fell in negative-price periods in 2025, up from 3% in 2021: 24%; Source: RVO, Monitor Zon-PV 2026
requests to feed electricity into the grid are waiting for capacity at regional grid operators (June 2026): 8,500+; Source: Solar Magazine, based on Landelijk Actieprogramma Netcongestie

A battery that switches every cell on its own.

Today’s grid batteries wire thousands of cells into long strings behind a central inverter. Their management system measures every cell but cannot switch one, so each string is held back by its weakest cell. Our battery switches every cell individually and gives weaker cells less work, with the power conversion built in. AI servers have pushed the MOSFETs that make this practical into high-volume production, and we benefit from that scale.

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Cell-level switchingEach cell’s duty cycle set by its charge and health
Power electronics built inPower conversion inside the battery: fewer steps, fewer parts
Designed for 20+ yearsWithout the capacitors that wear out today’s inverters first
Sodium-ion readyDesigned for sodium-ion and LFP cells
ModularStandard modules, designed to scale up to grid-scale installations

Progress

From first simulation to a grid-synchronised prototype in 2026.

Our lab prototype generates 50 Hz AC directly from its cells and runs in step with the grid. The next steps build up to a 5 MWh BTTRY container.

2025
BTTRY starts
The idea for a new kind of grid battery, built from the cell up.
Spring 2026
Concept & simulation
Battery pack simulations and the control concept for switching individual cells.
Aug 2026
Synchronised with the grid
Our lab prototype generates 50 Hz AC directly from its cells and runs in step with the grid.
Oct 2026
Lab prototype
Switches each of its cells individually and balances them during operation.
Current stage
Step 1
Real-scale module
A module at full scale, built and connected to the grid.
Step 2
Full single‑phase prototype
A complete single-phase battery: our biggest step from the lab towards a product.
Step 3
Certified commercial prototype
A three-phase battery of about 220 kWh, certified to IEC 62619, EN 50549 and CE, running at a partner site.
Step 4
First 5 MWh container
A 5 MWh battery built by BTTRY, in operation and building our track record.

The timing of the next steps depends on engineering, funding and partner sites.

Founders who have taken hard tech to market before.

Two TU Delft engineers with close to twenty years each of turning complex technology into products: from AI medical imaging taken through FDA clearance to acquisition, to offshore motion-compensation systems running 24/7 worldwide.