Lithium-ion batteries power the many electronic devices that we rely on every day, from EVs to smartphones and laptops. They’re so prevalent, that the average American owns nine lithium battery-powered devices.1 But they carry real risks when quality lapses occur. Overheating and fire hazards can cause property damage, injuries, or worse. With millions of these batteries in circulation, even a single defect can have a ripple effect of consequences for consumer safety and brand reputation.
Recently, Anker recalled over one million PowerCore 10000 power banks, model A1263, produced between 2016 and 2019 and sold through 2022.2,3 Anker has provided a general warning that the lithium-ion battery can overheat, but they have yet to share the exact reason for the recall. Armed with our Neptune Industrial CT Scanner and five A1263 power banks from Lumafield team members, we set out to see if we could identify the source of this recall. Could we identify the defects with CT scanning? And could CT inspection during development or manufacturing have prevented the faulty power banks from shipping in the first place?
Scanning Setup
We procured five potentially-affected power banks from various Lumafield colleagues, which we labelled PB1, PB2, PB3, PB4, and PB5. We then ran the serial numbers against Anker’s recall form, and determined that three of our power banks were impacted, while two were not.
The power banks were scanned using Lumafield’s Microfocus Neptune. This configuration’s small X-ray spot size makes it the ideal tool for resolving fine details in electronics and batteries.4
Use the embedded Voyager window below to explore the CT scan of the recalled power bank. Rotate and examine it from any angle.
First Look: Battery Cells
The first element we compared across the power banks were the battery cells themselves. A lithium-ion battery consists of two separated electrodes. The anode, usually graphite, stores lithium ions during charging. The cathode, typically a layered metal oxide, releases and accepts lithium ions as they move through the electrolyte during charge and discharge, enabling reversible energy storage.
There are a few common defects in the battery manufacturing process that can be easily spotted in a CT scan. For example, in lithium-ion batteries, it’s important to ensure that the anode has a sufficient overhang above the cathode, preventing the lithium plating that can lead to dendrite formation.5 Dendrites can subsequently result in degraded performance and short circuits, which can cause the worst-case scenarios of thermal runaway. CT scanning can also be used for Foreign Object Detection (FOD) within batteries, as particle contamination can lead to reduced performance and potentially short circuits.
The A1263 power banks each contain three 18650 lithium-ion battery cells inside. It was quickly apparent that batteries from at least two different suppliers had been used within the affected power banks. The cells in PB1 (recalled), PB2 (recalled), PB4 (not recalled), and PB5 (not recalled) seemed similar, but the cells in PB3 (recalled) had a few key differences.
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