In June, Anker initiated a recall of over one million of its PowerCore 10000 power banks due to a potential fire safety risk related to an issue with the lithium-ion battery.
Seeking to illuminate the potential cause of the reported overheating incidents, Lumafield, a firm specializing in X-ray CT scans, conducted an investigation into the recalled devices. Lumafield examined five PowerCore 10000 units from its own inventory, labeling them PB1 through PB5. Upon cross-referencing the serial numbers with Anker’s recall form, it was determined that PB1, PB2, and PB3 were part of the recall, while PB4 and PB5 were not.
The investigation commenced with a CT scan of the battery cells within these power banks. The scans revealed that each unit contained three battery cells and that Anker utilized at least two different suppliers for these cells. This was evidenced by variations such as the number of vents on the cells, and the presence of a mandrel—a cylindrical component designed to prevent core collapse—only in PB3’s battery cells.
Despite these differences, the battery cells themselves were ultimately ruled out as the primary cause of the issue. Lumafield’s scans found no apparent defects in the cells, such as dendrites or particle contamination, which could lead to overheating. Furthermore, PB1 and PB2 contained battery cells similar to those found in the non-recalled PB4 and PB5 units, and PB3 even featured the additional protection of a mandrel.
The focus of the investigation then shifted to the printed circuit board (PCB) and its assembly. It was here that Lumafield identified a significant difference between the recalled and non-recalled units. PB4 and PB5, the non-recalled power banks, utilized insulated wires for their positive and negative connections. In contrast, PB1, PB2, and PB3—the recalled units—employed flat tab wire for the entirety of these connections.
Further examination of the recalled units revealed variations in the assembly of these connections. Specifically, the distance between the positive and negative bus bars differed across PB1, PB2, and PB3. Lumafield highlighted that the short distance combined with a distortion to the tab wire in PB3 made it more susceptible to a short circuit compared to the other units.
While Lumafield’s findings offer compelling insights into potential design and manufacturing variances, the precise root cause of the overheating issues leading to the Anker recall remains officially unconfirmed by the company. The firm’s analysis provides a plausible explanation for the reported problems. Coincidentally, Anker recently published a blog post outlining its future plans to enhance battery safety across its product lines, indicating a commitment to addressing such concerns.
