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Laminated Busbars for Solar and EV – Why Aluminum is Gaining Traction

10/13

2026

By A&JLINK Engineering Team · Last updated October 2026 · 7 min read
The short answer
What is pulling aluminum into solar and EV busbars — and what it costs you in space.
  • ✓Two forces: weight and cost. For equal resistance, aluminum weighs about half as much as copper — and costs less per kilogram.
  • ✓The trade-off is space. Aluminum needs ~1.6× the cross-section, so it wins where the envelope allows.
  • ✓A per-connection decision. Not "copper or aluminum globally," but which connections suit which.
For years, a laminated busbar in a solar inverter or an electric vehicle was copper almost by default. Copper conducts best, it is easy to weld, and it fits into tight spaces. But across both of these industries, the default has been shifting toward aluminum — not because aluminum conducts better, but because the economics and the physics of these two applications now point the same way.
Scope: this article looks at the aluminum busbar applications gaining ground in solar and EV, what aluminum does well, what it demands from the design, and where it still makes sense to stay with copper.

1. Why Aluminum Is Gaining Traction in Solar and EV

The shift is driven less by a new discovery than by a change in what these two applications value. Solar inverters are mounted on structures and enclosures where weight means material and handling cost. EV battery packs are carried on the road, where weight means energy consumption. In both cases, mass is not a neutral property — it is a cost that shows up on every unit.
For an aluminum busbar in these applications, that calculus favors the lighter material. What used to be a niche choice has become, in many solar and EV designs, the default starting point — with copper reserved for the cases where space or current density are the binding constraint. The aluminum busbar applications driving this shift share one trait: they value mass and cost more than volume.

2. The Two Forces Behind the Shift: Weight and Cost

The reasons come down to two, and they reinforce each other.
Weight. Aluminum's density is about 2.70 g/cm³ against copper's 8.96 — roughly a third. It conducts less well, so it needs a larger section for the same current; but multiply the two effects and, for equal resistance, an aluminum assembly weighs about half as much as the copper equivalent. That property is what makes laminated bus bars in aluminum so attractive for weight-sensitive designs like solar and EV. In a moving vehicle or a rooftop structure, that saving is real money.
Cost. Aluminum is cheaper per kilogram, and its supply chain is less volatile than copper's. Combined with the weight saving, it makes aluminum attractive on both the material line and the total-cost line — as analyzed in our copper-versus-aluminum cost breakdown.
The catch is space. Because aluminum needs roughly 1.6 times the cross-section for the same resistance, the material only wins where the envelope can accommodate a larger conductor.

3. Aluminum in Solar Power Systems

Solar power is a natural home for aluminum busbars for one structural reason: weight is expensive on a solar installation.
Inside a photovoltaic inverter, the busbar carries the DC link current between the capacitors and the switching modules. Mounted on a frame, on a roof, or in a combiner box, each kilogram of conductor adds to the support structure and the handling effort.
That matters because a solar installation is built from many such parts, and its structure is priced by the kilogram. A busbar that is lighter reduces the load the frame has to carry, which lets the whole assembly be lighter again — a compounding saving rather than a one-off.
For a photovoltaic laminated busbar, the aluminum case rests on the same three points: low weight, low material cost, and enough space to absorb the larger section.

4. Aluminum in EV Power Systems

Electric vehicles push the same logic harder, because there the weight saving pays back every kilometer.
An EV battery pack and its power electronics are mass-sensitive by design — range is a function of mass, and manufacturers treat every kilogram as a cost. A busbar running from the modules to the inverter is a candidate for aluminum wherever the pack has room for the larger section, which it usually does. The result is a lighter pack with a lower material cost, at the price of a bulkier conductor — a trade most EV platforms are willing to make once the pack envelope is set.
For a laminated busbar for EV, the aluminum case is strongest in the higher-current connections — battery-to-inverter and module interconnections — where the material's cost advantage per amp is largest.

5. What Aluminum Demands from the Design

Aluminum is not a drop-in swap for copper, and the strongest aluminum busbar applications account for four differences.
Cross-section. Expect roughly 1.6 times the area for the same resistance — which has to be planned into the layout, not discovered after the enclosure is drawn.
Joining. Aluminum's tenacious oxide layer makes welding and brazing harder than copper's, so the process has to be chosen and controlled rather than assumed.
Dissimilar-metal junctions. Where aluminum meets copper, the junction needs the right surface treatment to avoid galvanic corrosion.
Plating. Surface treatment (tin, nickel, or silver) protects the aluminum and keeps contact resistance stable in a humid or polluted environment — a real consideration for both rooftop solar and under-vehicle systems.
None of these is an obstacle; together, they are the reason an aluminum busbar is engineered rather than simply specified.

6. Where Aluminum Fits — and Where It Doesn't

Aluminum is the better choice when weight or cost is the constraint and space is available — high-current runs in solar inverters, EV battery packs, and energy storage. It is not the better choice when space is the constraint or the current is modest: there, copper's smaller section and easier processing usually win.
That is why the sensible approach is not "copper or aluminum globally" but a per-connection decision, made against the actual current and the actual envelope.

7. What to Specify for an Aluminum Laminated Busbar

When specifying aluminum for solar or EV, work through these: current (continuous and peak), available space (can it take the larger section?), weight budget (how much does the saving buy?), temperature range and cooling, plating and corrosion protection, joining method and dissimilar-metal junctions, and qualification evidence. Because these applications rarely allow a standard part, the busbar is designed around the envelope — and the earlier aluminum enters the design conversation, the more of its weight and cost advantage survives into the finished product.

8. Frequently Asked Questions

Why is aluminum used in solar and EV busbars?
Because weight and cost matter more there than space. Aluminum weighs about half as much as copper for the same resistance and costs less per kilogram, and both applications usually have room for the larger section.
Does aluminum conduct as well as copper?
No — about 61% of copper's conductivity by volume. That is why it needs roughly 1.6 times the cross-section; on a per-kilogram basis, though, aluminum conducts better.
Is aluminum always the cheaper choice?
Not always. It is usually cheaper per amp at high current, but where space is tight, copper's smaller section can be the cheaper total solution.
Why is aluminum gaining traction now?
Because solar and EV designs increasingly treat mass and material cost as first-order concerns. As those priorities dominate, the lighter, cheaper material becomes the default in more connections.

9. Summary

In solar and EV aluminum busbar applications, aluminum is gaining traction because those two industries value the two things it does best — it is light and it is cheap — and usually have the space its larger cross-section requires. For the same resistance it weighs about half as much as copper, which pays back in structures and in range; the price is 1.6 times the section and more care in joining and corrosion protection. The right question is not whether aluminum beats copper, but which connections in your design should use which. Talk to our engineers about your solar or EV power requirements.
Building a Solar or EV Power System?
Send us your current, envelope, and weight targets — our engineers will recommend the material and section that fit.
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