ZEISS argues that a cell factory cuts scrap by deciding early which cells to reject, and it wants that decision made on the production line, not in the lab. BetterE Expedition published an interview and a headquarters tour at ZEISS in Oberkochen on 6 October 2026, with Robert Zarnetta of ZEISS Industrial Quality Solutions and ZEISS’s global lead for battery X-ray applications.
Scrap is the share of cells a factory makes and then rejects. A 2024 white paper by Fraunhofer FFB and PEM of RWTH Aachen put it at 15 to 30 percent in the first years of cell production, and still around ten percent after five. It put each percentage point at around 30,000 euros a day, without naming a plant size (Fraunhofer FFB, October 2024). Every point of yield is worth money every day of a ramp-up.
By the Numbers: Four Cells a Minute, About Four Cents a Cell
- 4 prismatic cells a minute — One inline CT machine, four corners scanned per stacked cell, according to ZEISS (BetterE Podcast, 2026)
- About 110 cylindrical cells a minute — ZEISS’s 2D inline X-ray inspection, according to ZEISS (BetterE Podcast, 2026)
- One system per 1 GWh line — ZEISS’s rule of thumb for one assembly line (BetterE Podcast, 2026)
- About 4 cents a cell — ZEISS’s rough calculation for 100% inline 3D X-ray inspection; currency not stated (BetterE Podcast, 2026)
- 15 to 30 percent — Scrap common in a cell factory’s first years, around ten percent after five (Fraunhofer FFB / PEM, 2024)
- Over 80% — China’s share of global cell manufacturing capacity; the EU holds 6-7% (IEA, 2026)
- €11.896 billion — ZEISS Group revenue in fiscal year 2024/25, up 9%, according to ZEISS (ZEISS, December 2025)
An Optics Maker From 1846 Now Sells Inspection to Cell Factories
Carl Zeiss opened a workshop for precision mechanics and optics in Jena in 1846, according to the company, which is now headquartered in Oberkochen and has 46,622 employees. Light microscopy was the basis 180 years ago, Zarnetta says; the portfolio has since grown into electron microscopy, CT and coordinate measuring systems. For batteries, its own material sets out six quality gates, from material development to module assembly. Batteries do not show in the accounts: the segment that holds the business, research microscopy included, earned €2.334 billion in fiscal 2024/25, down 1%.
Inspection Moves Inline Because Lab Statistics Hit a Wall
For the BetterE Podcast, Simon Voß of BetterE Expedition toured ZEISS’s customer center and production basement. Zarnetta describes how ZEISS came to batteries through battery materials and academic customers. It then followed the industry into mass production and into China, where it built its global competence center for battery applications. His colleague started as a CT application engineer and saw battery customers arrive wanting to know what happens inside their cells.
Zarnetta’s starting point is yield. He sees quality challenges at every step from battery material, slurry and calendering through slitting, cutting and stacking to putting the stack into its can. Customers hit a wall with statistical process control alone, he says. Only inline inspection lets a factory decide early whether to process a cell further, which costs a lot of money, or to reject it. What ZEISS sells is the moment to stop spending on a bad cell.
Both 2D and 3D are needed, the X-ray lead says; they are not alternatives. A 2D image is one picture in which information overlaps, so a particle’s position is known in one direction only. A CT volume is reconstructed from thousands of 2D projections, and its cross-sections show where a particle sits and how big it is. An aluminium cathode tab, she adds, has very low X-ray contrast and overlaps the anode tab in a side view. Some defects cannot be seen in two dimensions.
In the basement, the INRADIA 3D runs in the production takt. Robots feed prismatic cells into the machine, which inspects four corners of four batteries within one minute, Zarnetta says on the tour. At that speed the battery cannot be rotated, so it stays static in the beam while the X-ray source and detector rotate around each corner. Inside sits a small data center for the algorithms. It moves the camera, not the cell.
Corners carry the overhang, the distance between the anode and cathode edges, which must stay within tolerance or it can cause a short circuit. In a stacked prismatic cell, the X-ray lead explains, each layer is placed separately, so a shift cannot be predicted. Corners are also likely to be folded or damaged when the stack goes into its casing. Customers told ZEISS that overhang inspection for stacked cells is a must. Inline inspection is always a compromise against the lab’s resolution, Zarnetta adds, and ZEISS found the sweet spot on site with the big battery manufacturers in China. It was tuned in Chinese factories.
Four Cents Is ZEISS’s Own Number, and Who Pays Is Still Open
Its most quotable figure is also its least tested. Zarnetta’s rough calculation puts full 100% inline 3D X-ray inspection at about 4 cents per battery, machine, X-ray source maintenance and service included. He names no currency and calls it almost per mille of the cell’s cost, depending on cell size. MONOist reported about USD 0.04 per cell from ZEISS at Hannover Messe in April 2026. Consistent, then, but still ZEISS’s own figure.
Throughput depends on the job. The 4 cells a minute are stacked prismatic cells with four corner scans each. MONOist reported the Hannover Messe demonstration at up to 10 cells a minute without stating the cell format. Those two numbers are not the same measurement.
Who pays is an ongoing debate, Zarnetta concedes. Automotive OEMs have their reputation on the line, and a car recall is much more expensive; battery manufacturers are pushed down on price and need factory space for the equipment. A ZEISS representative at Hannover Messe gave the example of an automotive supplier receiving one million batteries, 1,000 of them defective: a recall could follow. The cell maker buys the machine; the carmaker carries the recall.
Calibrated Metrology Is What ZEISS Brings to the Line
Over the last 20 years, Zarnetta says, ZEISS has learned to calibrate its CT systems for repeatable, traceable metrology results, and the same capabilities exist on the inline INRADIA system. As a rule of thumb, a typical 1 GWh assembly line needs one such system; factories scale by running lines in parallel. A traceable measurement is what turns an image into a reject decision.
Upstream, the work is less spectacular. On the tour, a robotic system automates the light-microscope analysis of particle-trap filters, which battery factories run by the hundreds. Burrs, the sharp edges left on cut electrode foils, are quantified by size and criticality, so operators can change the knives or adjust the laser power. Fraunhofer’s 2024 white paper with PEM made the same case: digital quality assurance and traceability can reduce reject rates at an early stage. Its value lies in feeding results back to the process.
Nobody Has Defined a Critical Defect, and Europe Holds Little Capacity
A harder problem is definition. Zarnetta names standardisation as a challenge in Europe and in China, because what counts as a critical defect is a moving target. No one has defined the smallest critical particle size, and it is open whether 3D inspection is required. Without that, every inspection budget stays negotiable.
China’s success, the X-ray lead says, rests on a complete supply chain in one country, while Europe’s companies sit in different countries and find it hard to unite behind one goal. China holds over 80% of global cell manufacturing capacity, the EU 6-7% (IEA, 2026). Zarnetta calls it a chicken-and-egg problem: a supplier has to win where batteries are produced today before European players recognise it. That is why ZEISS built its Shanghai battery competence center with R&D, the speakers say. Europe could contribute its strength in industrial standardisation, the X-ray lead suggests. Europe could write the defect standard the machines are waiting for.
Bottom Line
Against around 30,000 euros a day for each point of scrap in the 2024 FFB/PEM estimate, about 4 cents a cell looks small. That holds if the machine catches what ZEISS says it does. That figure is ZEISS’s own, and nobody has agreed what a critical defect is. Zarnetta’s challenge is for producers to bring ZEISS inline inspection requests from Europe too, not only from China. The cheapest cell to reject is the one rejected early.
Battery Business Insights is an independent industry publication. Figures reflect the most recent data available at the publication date. Company statements, targets and estimates are stated as such and are not confirmed outcomes.
References: BetterE Expedition (1, 2); Fraunhofer FFB; IEA; MONOist; ZEISS (1, 2, 3); ZEISS Microscopy.
