The APC battery is a compact, modular static zinc battery system developed by Cayrex, designed to challenge conventional lead-acid batteries. Based on the Hyperflow concept, the APC battery delivers good performance while maintaining the familiar compact form factor that industry and consumers already know.
The APC battery is strategically positioned between lead-acid and lithium batteries — offering significantly better cycle life, safety, and upgradability than lead-acid systems, at a target price point currently comparable to AGM lead-acid batteries.
Unlike conventional batteries where the entire unit must be replaced when performance degrades, the APC battery can be upgraded or refreshed simply by replacing the electrolyte — a principle taken from the Hyperflow concept that makes it uniquely future-proof. Which means that the APC battery will be better and better over the time, with each electrolyte upgrade.
// Multi-chemistry platform
One hardware. Multiple chemistries.
The APC battery ships with a zinc-bromine (Zn-Br) default electrolyte. Thanks to neutral multi-chemistry cells based on the Hyperflow concept, users can switch to alternative zinc-based chemistries without any modification to the battery hardware.
Zn-Br
Zinc-bromine
Default
Zn-Mn
Zinc-manganese
Alternative
Zn-I
Zinc-iodine
Alternative
// Key Advantages
Built differently from the start.
// Cell innovation · FCD cells
Self-healing protection against zinc dendrites
Zinc dendrites are the classic failure mode of zinc batteries: they grow during charging and can short-circuit a cell. APC cells built on the FCD architecture contain a self-healing material that stops dendrites before they can cause a short, so the cell recovers instead of failing. Developed in-house and tested in our laboratory cells.
Store for years — fully discharged NCD only
Lead-acid, lithium-ion and sodium-ion batteries all suffer from calendar aging — their capacity and performance degrade over time even when unused. With the NCD architecture, the APC battery can be fully discharged and stored for years without degradation.
Safe, zinc-based chemistry
Water-based zinc electrolyte is non-flammable and non-explosive — no thermal runaway, no toxic fumes. Zinc is abundant and ethically sourced, with no lithium, cobalt, or nickel supply concerns.
Upgradeable by electrolyte swap
The APC battery is built around two cell architectures — NCD (Neutral Cell Design) and FCD (Fixed Cell Design). With NCD cells, the battery can be refreshed or upgraded simply by replacing the electrolyte, no cell modifications needed. With FCD cells, upgrades are performed by replacing the cells themselves for higher capacity and power. Either way, the entire unit doesn't need to be replaced.
Multi-chemistry compatibility
One hardware platform, multiple electrolyte options — Zn-Br, Zn-Mn, Zn-I — without any modifications to the battery only by replacing of the electrolyte (NCD cell Architecture).
Long cycle life
Significantly more charge-discharge cycles than lead-acid systems, lowering total cost of ownership over the battery's lifetime.
Recyclable & sustainable
The battery can be refreshed with swaping the old electrolyte with new electrolyte only. And the used electrolyte can be recycled and reformulated for new production. Cell components are simple and easy to recover at end of life.
Based on the Hyperflow concept
A compact static design based on the Hyperflow concept — without pumps, external tanks, or moving parts.
// Performance
Current cell performance.
Standard performance of the current V5 static Zn-Br₂ cell: around 200 mWh/g specific energy, with stable cycling over 100 cycles — coulombic efficiency close to 98% and energy efficiency around 80%.
V5 — discharge curve · 200 mWh/gV5 — specific energy, CE & EE over 100 cycles
// Development progress
Next cell: up to 380 mWh/g.
First results from the new high-performance FCD Zn-Br₂ M-C cell show stable charge–discharge behaviour over the first 15 cycles, reaching 360–380 mWh/g — nearly double the specific energy of the current V5 cell.
High-performance FCD Zn-Br₂ M-C — cycles 2–15
Two distinct cell architectures.
The APC battery is designed to accommodate two distinct cell architectures, allowing customers to choose the configuration that best matches their application requirements, performance needs, and budget.
NCD
Neutral Cell Design Architecture
The NCD architecture represents the simpler, more cost-effective approach. Cells are constructed with minimal components, making them extremely easy to manufacture and recycle. Any upgrade or chemistry change is accomplished purely by replacing the electrolyte — no cell modifications needed.
FCD
Fixed Cell Design Architecture
The FCD architecture is a high performance cell design that delivers higher capacity and power output than NCD. Upgrades are performed by replacing the cells themselves rather than just the electrolyte, offering greater performance potential at the cost of slightly more complex manufacturing.
Suitable wherever lead-acid is used.
The Hyperflow APC battery thus supports a wide range of applications and is suitable for almost any use where lead-acid batteries are currently used — from small to medium-sized energy storage systems, emergency and backup power, telecom and UPS infrastructure, to mobile solutions including marine, automotive, and DIY energy projects.
Small to medium energy storageEmergency and backup powerTelecom infrastructureUPS systemsMarineAutomotiveDIY energy projects
// Gallery
APC in the lab.
// R&D Progress
Active development updates.
Cayrex APC is in continuous development. Below is a chronological record of milestones — cell tests, electrolyte breakthroughs, and architectural iterations — that mark the path toward a market-ready product.
August 2026Electrolyte upgrade · V5 → next cell
Electrolyte upgrade — from 200 to 380 mWh/g
A side-by-side comparison of the current V5 static Zn-Br₂ cell (~200 mWh/g, stable over 100 cycles) and the new high-performance FCD Zn-Br₂ M-C cell (~380 mWh/g, 99% CE in the first result). The comparison shows what an upgraded electrolyte and cell design can deliver on the same zinc-bromine chemistry — nearly double the specific energy.
Left: V5 current cell (~200 mWh/g, CE ~98%), trend to 100 cycles. Right: high-performance FCD Zn-Br₂ M-C, first result (~380 mWh/g, 99% CE).
June 2026FCD Architecture · V3 cell
New High Performance V3 Zn-Br₂ cell — FCD architecture cycling test
New V3 cell based on the Fixed Cell Design (FCD) architecture, tested with a Zn–Br₂ M-C electrolyte. The voltage vs. specific energy curves show stable cycling behavior, reaching approximately 360–380 mWh/g at discharge — promising results for a static Zn-Br battery.
Zn–Br₂ M-C V3 cell — voltage vs. specific energy. FCD architecture, June 2026.
November 2025FCD Architecture · BCA comparison
Static Zn–Br₂ FCD cells — TBAB vs. MEP electrolyte comparison
Side-by-side test of two static Fixed Cell Design (FCD) Zn–Br₂ cells using different bromine complexing agents (BCAs): TBAB (tetrabutylammonium bromide) and MEP (N-methyl-N-ethylpyrrolidinium bromide). The voltage-vs-specific-energy curves reveal a dramatic difference in achievable energy density: the MEP-based cell delivers ~360 mWh/g, roughly 3× more than the TBAB-based cell (~120 mWh/g). Both cells share the same FCD architecture, but the choice of BCA fundamentally shapes the energy storage capacity.
Voltage vs. specific energy — static Zn–Br₂/TBAB cell (blue) vs. static Zn–Br₂/MEP cell (red). Both use FCD architecture.
September 2024NCD Architecture · Electrolyte · Bromine management
Colloidal Zn–Br electrolyte for NCD cells — bromine sequestration without BCA additives
Test of a custom colloidal electrolyte formulation designed for the Neutral Cell Design (NCD) architecture, holding bromine in place without conventional bromine complexing agents (BCAs like MEP or TBAB). The left photo shows the colloidal electrolyte retaining bromine at the electrode surface — visibly clearer solution above. The right photo shows a regular 2 M ZnBr₂ aqueous electrolyte, where bromine diffuses throughout the cell and discolors the entire bulk.
Left: custom colloidal electrolyte (NCD architecture) holding bromine at the electrode. Right: standard 2 M ZnBr₂ aqueous electrolyte with bromine diffusion throughout.
The voltage-vs-time curves over a 40 h period further confirm the benefit: the colloidal electrolyte (blue) maintains voltage above 1.72 V for the entire test, while the standard aqueous 2 M ZnBr₂ (green) drops below 1.3 V — a clear indicator of bromine crossover and self-discharge in the conventional formulation.
Voltage vs. time over 40 hours — colloidal Zn–Br vs. aqueous 2 M ZnBr₂.
// APC Battery
Replacing the lead-acid stack.
Telecom operators, UPS integrators, system installers — APC is a compact static design based on the Hyperflow concept, designed as a drop-in replacement for lead-acid batteries.
