BAALSCRAP enables battery cell housings produced from scrap

As demand for electric vehicles increases, aluminium is becoming increasingly important for achieving net‑zero emissions in the automotive industry. By 2030, the aluminium content of an average passenger car is expected to reach approximately 260 kg.

At the same time, progress is being slowed by conservative material specifications, particularly in battery‑related applications, where increased use of scrap is central to a circular aluminium industry.

The Net Zero Industry‑funded project BAALSCRAP investigates how production processes are affected by unwanted alloying elements and impurities in scrap‑based aluminium, by developing a deeper understanding of material behaviour. Preliminary results show strong potential to reduce the climate footprint.

Aluminium alloys for batteries are currently produced with a strong focus on stable processes, low variation, and cautiously selected alloy chemistry. In practice, this has led to production being almost entirely based on primary aluminium, with very narrow limit values for elements such as copper, chromium, magnesium, and zinc.

These limits are intended to ensure good material properties and to avoid defects such as porosity and welding‑related cracking, but they have also largely excluded the use of recycled aluminium, particularly post‑consumer scrap.

The initiators of the project, Gränges, identified customer specification requirements as a key barrier to introducing recycled aluminium into production. When the project partners began examining the origin of the limit values, it also became apparent that there was no clear technical justification behind them.

– We saw very high customer requirements regarding chemical composition. When we asked where these limits came from, it turned out that the narrow limit values originated from a single customer and had been passed along through the entire value chain, without support in published research, says Shirin Nouhi, researcher and group leader at Swerim.

Testing beyond today’s limits

The research team developed sixteen aluminium alloys with varying levels of magnesium and zinc, far above today’s accepted limits. Through small‑scale casting, rolling, and heat treatment, it was possible to simulate industrial conditions at low cost.

All alloys were processed and welded under identical conditions, making it possible to clearly study the influence of chemistry.

– Swerim’s laboratory capacity has been crucial. Instead of performing full‑scale trials, we can simulate industrial processes using just two kilograms of material,” says Joacim Hagström, Senior Specialist in Physical Metallurgy and Metallic Materials Properties at Swerim.

Higher levels increased stability

Small additions of magnesium and zinc (below 0.05%) had no effect on stability or porosity, but at 0.1% the porosity decreased drastically. At a combined addition level above 0.2% of the elements, stability improved further, and all samples outperformed the reference material from current production.

– What surprised us most was that once you pass a certain threshold, the weld becomes much better. At high levels of magnesium and zinc, we observed fewer pores than in today’s material, says Shirin Nouhi.

When it comes to hot cracking, there is a clear correlation with the magnesium content, weld penetration, and microstructure. The addition of magnesium changes the grain structure from columnar to equiaxed, which reduces the risk of crack formation. This is also supported by thermodynamic modeling, but further research is required to fully understand the phenomenon.

From a sustainability perspective, the results are very interesting. If these levels can be transferred to an industrial scale, they would enable a significantly higher content of recycled material in battery alloys, which in turn could lead to a substantial reduction in carbon footprint.

Today, 90 percent of total carbon emissions from production are found in Scope 3, and calculations from Gränges indicate that the use of recycled aluminium could reduce emissions to almost zero.

Challenging established standards

BAALSCRAP is a collaborative project involving Gränges, Kedali, Scania, and Swerim. Initially, Northvolt and Novo Energy also participated, but both companies were forced to leave the project, which has, among other things, delayed work on full‑scale trials.

At the same time, the project has highlighted broader challenges for the industry, where established standards and customer requirements can constitute significant barriers.

– The results show that some established standards and limit values, which are not always clearly supported by research, need to be reassessed. This would make it easier to use more recycled material – something that is crucial for achieving ambitious zero‑emission goals,” says Shirin Nouhi.

The next step is full‑scale production testing to ensure that the laboratory results can be transferred to industrial scale. If successful, BAALSCRAP could not only enable battery components with a lower climate footprint, but also lead to a reassessment of how material requirements are defined across the entire aluminium value chain.