Driving Innovation in Automotive Relay Box Systems: A Deep Dive into 800V Benchmarking Insights

In the ever-evolving automotive industry, optimizing relay box systems is a key driver of efficiency, cost-effectiveness, and vehicle performance. As the push towards 800V architectures in electric vehicles (EVs) accelerates, manufacturers are making strategic design choices to enhance power distribution, weight reduction, and cost control.

Our latest A2MAC1 benchmarking study analyzed 800V relay box systems across 17 top-performing vehicles worldwide. The goal? To uncover key trends and best practices in busbar weight, number of relays, and overall system complexity.

Key Areas of Focus
To understand how OEMs are achieving cost and performance gains, we examined two critical factors:

1. Busbar Weight Optimization

The busbar is a crucial component in relay boxes, serving as the primary conductor for power distribution. Our findings reveal that:

• Lighter busbar designs contribute to overall vehicle weight reduction, directly impacting energy consumption and driving range.
• OEMs are shifting from copper to aluminum due to its weight and cost advantages, ensuring a balance between conductivity and manufacturing feasibility.
• The Hyundai Ioniq 6 and Kia Niro EV Wave 2023 feature the most cost-effective aluminum busbars, optimizing both weight and efficiency.
• The GMC Hummer EV has the highest busbar weight (8.31kg, aluminum), impacting its cost-effectiveness.

2. Number of Relays and Components

Reducing the number of relays and components without compromising functionality is a major industry goal. Our analysis highlights:

• Most competitors have two or three relays inside the battery pack, but the GMC Hummer EV stands out with eight main relays totaling 3kg, significantly increasing weight and cost.
• Tesla vehicles and Toyota BZ4X, Fisker Ocean One, Smart Premium, and Nissan Ariya all contain four relays per battery pack, maintaining a balance between efficiency and cost.
• Zeeker’s relay system includes five relays, designed for enhanced fast charging capabilities.
• The Tesla Cybertruck AWD features a relatively high relay box weight (10.65kg) and 100 components, presenting room for cost savings by optimizing the number of components and relay weight (0.937kg per relay).

Key Findings: Industry Trends & Best Practices

Our benchmarking study has unveiled significant trends shaping the future of relay box systems:

1. Aluminum Busbars for Cost & Weight Reduction

• More OEMs are opting for aluminum over traditional copper to reduce both cost and weight.
• Advancements in coating technologies are improving aluminum’s conductivity and corrosion resistance.
• The Hyundai Ioniq 6 and Kia Niro EV Wave maximize busbar efficiency with lightweight aluminum, making them the most cost-effective solutions.

2. Minimizing Complexity for Higher Efficiency

• Reducing the number of relays leads to simpler, more efficient designs.
• The GMC Hummer EV has the highest number of components (133) and relay box weight (25.19kg), indicating an opportunity for greater cost optimization.

3. Space Optimization & Integrated Solutions

• Compact relay box designs maximize available space, supporting tighter vehicle packaging.
• Tesla’s unique approach eliminates pre-charge relays, instead using a Double Pole Double Throw System to switch from 400V to 800V.

Why This Matters for the Automotive Industry

Relay boxes are often overlooked but play a critical role in vehicle electrical systems. Optimizing their design leads to:

• Lower system costs, contributing to overall vehicle affordability.
• Improved efficiency, extending EV range and performance.
• Greater reliability, reducing maintenance and warranty costs.

As EV adoption rises, automotive engineers, designers, and procurement teams must rethink their approach to relay box architecture to maintain a competitive edge.

What’s Next? The Road to Innovation

These findings present exciting opportunities for OEMs and suppliers to collaborate on next-generation relay box solutions. Key areas for continued development include:

• Further integration of solid-state switching technologies.
• Enhanced materials innovation for busbar conductivity and durability.
• Smarter relay box layouts for modularity and scalability in EV platforms.

Join the Conversation

How are you tackling relay box optimization in your projects? Let’s exchange insights:

• What strategies are you exploring to improve relay box efficiency?
• How do you see busbar design evolving in the future of EVs?

We invite industry professionals to connect with us to continue driving innovation in power distribution and electrification!