Another Sony WF-1000XM4 battery failure

In my previous post, I used the word exploded and I will admit it was the wrong term, failure might be a better term in the previous case, but perhaps not this one.

From talking to the user on Reddit, this seems more like an actual case of the battery exploding than just failing and popping open. Here are some of their replies to my questions:

• The headset was purchased in July 2021 in Canada at London Drugs
• The user did experience battery drain and it was around 1-2 hours of battery life which is pretty pathetic
• The firmware was 1.4.2
• The user never had the batteries replaced, so they are the original ones from the factory
• Charging was via USB and not AC adapter
• Case did get warm during recharging, the LED also flashed red which is indicative of overheating according to the online guide

Here is what Reddit user akwok said occurred:

Context:

I took the earbuds off during a work meeting on my desk and a few minutes later was startled by a loud POP and a chemical-like smell. One of the earbuds had popped completely open and the inner battery (?) coil was split as well.

So this seems more like the small coin cell exploded, rather than just the adhesive failing. Perhaps such small coin cells fail (explode?) in this manner.

Close up shot of the battery.

So while not confirmed, I am suspecting the Zenipower batteries are at fault here. I wonder if Sony caught this during later production runs and fixed the issue or if this problem is still present in ALL WF-1000XM4 units.

If the issue is still present in all WF-1000XM4 batteries, the device needs a recall or fix because at this point, an exploding earbud in someone's ear might cause permanent damage. So if anyone from Sony is reading this. Time to start SOLVING THIS PROBLEM IMMEDIATELY, before someone gets hurt and you have a lawsuit on your hands.

I will caution any users who are suffering from severe battery drain and your headset warms up way too much during charging to stop using them, because an earbud exploding in your ear would not be ideal.