The Situation
In 2025/26, E-Tech supported a UK-based 50MW / 56.2MWh Battery Energy Storage System (BESS) project with Elpress AKK Al–Cu Bimetallic Cable Lugs. The facility provides rapid-response flexibility and helps integrate renewable energy into the 132kV network. The modular BESS site includes lithium-ion battery rows paired with Power Conversion Systems (PCS) and LV/MV distribution panels.
Client’s Pain Points
- The risk of unsafe or unreliable aluminium-to-copper (Al–Cu) transitions across battery racks, PCS units and LV/MV distribution equipment
- Aluminium conductor creep and joint failures due to 20–60°C temperature swings in containerised BESS during rapid charge/discharge cycles
- Potential for corrosion, hot joints and premature failures where terminations are poorly specified or inconsistently installed
- Vibration from HVAC cycling, inverter switching and transport, requiring high pull-out performance for reliability
- Keeping the project on schedule in a fast-paced, modular build
- Over 60% of electrical failures in BESS containers occur at termination points due to poor torque, inferior bimetal connections, mixed-metal corrosion and thermal hotspots
- Terminations for flexible aluminium cables requiring tight 90-degree bends without introducing mechanical stress
The Challenge
- Fully compliant with IEC61238-1, BS7609 and BS7727 Standards
- Proven for secure and durable Al–Cu interfaces in a high-current Battery Energy Storage System (BESS) and inverter-driven environment
- Resistant to galvanic corrosion and long-term degradation
- Suitable for fast, repeatable installation across multiple battery and PCS connections
- Capable of accommodating constrained termination geometries and tight 90-degree bends
- Supported by specialist technical expertise to ensure correct product selection, tooling and installation practice
UK BESS sites have experienced publicly documented thermal incidents, such as the Liverpool BESS fire (September 2020) and East Tilbury / Thurrock BESS fire (February 2025). Investigations routinely focus on electrical terminations and balance-of-system components as potential contributors to heat generation. Lithium-ion battery fires behave differently from conventional electrical fires, with prolonged burn and re-ignition risk. This highlights the critical importance of high-quality terminations and preventative design to minimise localised heating and escalation risk.
Why They Chose E-Tech
- An accurate selection of Elpress AKK Al–Cu Bimetallic Cable Lugs to meet the project’s technical and operational requirements
- Lugs rated for both stranded and solid aluminium conductors
- Stock availability in key sizes
- On-site installation support and tooling demonstrations to minimise errors
- Technical guidance and installer training for safe, efficient operation
- Ongoing lifecycle support through E-Tech’s Authorised Elpress Service Centre, including Crimping Tool Calibration, Maintenance and Certification
This gave the client confidence in the safety, efficiency and long-term reliability of their BESS site.
Our Solution: Elpress AKK Bimetallic Cable Lugs
The BESS project relied on Two-Hole Elpress AKK AlCu Bimetallic Cable Lugs, selected for their distinctive ‘square head’ design and engineered to provide secure aluminium-to-copper terminations. These lugs are precision friction-welded from solid materials, creating a uniform Al–Cu bond with high pull-out strength and excellent resistance to corrosion. When paired with Elpress-approved tooling, they deliver repeatable, specification-compliant connections in demanding, high-duty environments.
In compact LV/MV assemblies, wide round-palm bimetallic lugs can cause clearance issues. With space restricted on this site, only the compact palm geometry of the AKK lugs enabled safe phase-to-phase clearances, clean cable dressing and full insulation coverage, reducing installation time and rework. This highlights that not all compliant lugs are physically interchangeable in real-world installations.
The aluminium conductors were terminated using Indent Crimping with matched Matrix and Punch tooling in a Two-Crimp Sequence. This creates a high-pressure, gas-tight joint that ruptures aluminium oxide, interlocks the strands to reduce creep, and maintains stable contact resistance under thermal cycling and vibration.
Why this solution worked:
- Friction-welded Al–Cu construction: Maximum mechanical integrity with superior corrosion and vibration resistance
- Two-crimp installation sequence: Ensures certified, repeatable connections for both stranded and solid conductors
- Pre-insulated options: LSOH / halogen-free variants for safety-critical circuits
- Clear marking and tooling integration: Conductor area references and Elpress tooling ensure correct, error-free installation
- Supports CAPEX savings: Enables aluminium conductor adoption without compromising reliability or performance
*Please note, there are over 50 Elpress AKK variants available (16–1200mm²), including 33 Network Rail PADS-approved types
| Elpress AKK AlCu Bimetallic Lugs |
BESS Project Outcome
- Safe, reliable connections across all battery racks, PCS units and LV/MV systems
- Rapid, repeatable crimps maintaining programme milestones while minimising installation errors
- Accommodation of tight bend radii (up to 90°) without introducing mechanical stress
- Cost savings through the adoption of aluminium conductors without compromising performance
- Long-term operational reliability under high currents, thermal cycling and vibration
- Enhanced resilience and safety of the facility’s electrical infrastructure
By eliminating a known aluminium failure mechanism at installation, these terminations are engineered to remain electrically stable for decades, aligned with the intended life of a BESS project or transport asset. This reduces the need for mid-life inspections, re-torque programmes, unplanned outages or remedial works. By avoiding costly interventions and thermal events, it delivers value far beyond the initial installation cost.
Secure Your Aluminium-to-Copper Connections with Confidence
If you’re specifying aluminium cables or planning Al–Cu transitions on your next project, our Technical Sales Team can advise on lug selection, tooling and installation best practice. Explore the full Elpress Crimping System or speak with our experts now.
| 📞 +44 (0)1744 762 929 | 📧 sales@etechcomponents.com | Learn More: Elpress |