You Won’t Believe What This Sodium-ion Battery Survived

After six years in operation, we’ve seen everything—cross-threaded terminals, missing nuts, backwards wiring, you name it. But nothing hit us harder than what happened in 2023: a previous-generation lithium pack overheated for reasons we still can’t fully explain, and the whole thing erupted in a cloud of smoke (not fire, but visually bad enough). Overnight, social media went wild. That one pink Prius almost killed the company.

So naturally, the question haunted us:

“What if the same thing happened to a NexPower Sodium-ion pack? Would we watch another pink Prius burn our reputation to the ground?”

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Fast forward to December 17 2025, a week before Christmas.

A customer reached out about his 2006 Gen2 Prius running our V3 GT Sodium-ion pack, installed just six months earlier. The car was throwing P0A80 —every Prius owner’s least favorite. He sent us a Dr. Prius App screenshot:

Block #1 was way out of line—low voltage, sky-high internal resistance. Clearly, something wasn’t right.

We jumped on it.

Our team at NexPower worked closely with the customer, shipped him a replacement blade, and got his Prius back on the road. In return, he sent the original #1 blade back to us for investigation.

That’s when things got interesting...

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At first glance, the blade looked… normal !!

Nothing swollen, nothing charred, nothing that screams “I’ve been to 200+ degrees Celsius.”

There was a faint smell, but nothing alarming. The terminal stud showed some etching—classic minor arcing from installation, the kind of thing many DIYers have accidentally done and then forgotten about.

No melted plastic explosions. No blackened casing. Just a slightly “used” looking blade.

Then we pulled the cover and took a closer look at the circuit board.

That’s where the truth showed up.

The tin solder had melted and flowed.
For reference, pure tin solder melts at around 232°C (449.6°F).

Let that sink in.

Parts of the board and battery cells had clearly seen temperatures in that neighborhood. The “slight burning smell” we noticed? That wasn’t the cells. It was tape around the hot spots giving up.

No vented cells. No thermal runaway. No fire. No smoke show.

Just a blade that had quietly survived many trips to hell and back.

And here’s why that matters:

At around 200°C:

A LiFePO₄ pack would likely puff, vent, and smoke.
A NMC lithium battery? You really don’t want to be standing next to it while it set itself and everything around on fire.

But this Sodium-ion blade?

It sat in that abuse for months—probably close to six months—slowly cooking its cells, circuit board, melting solder, softening tape… and never once turning into a rolling fireball.

No cabin full of smoke.
No burned Prius.
No viral “NexPower battery explodes” headline.

Just a quiet, survivable failure that we could investigate, learn from, and improve on.

Conclusion

There are tons of lab reports and academic papers claiming how safe Sodium-ion chemistry is. Charts, graphs, safety curves—it all looks great on paper.

But you don’t feel it in your gut until you see a real-world pack that’s been roasted past solder-melting temperatures… and the car is still here to tell the story.

Meanwhile, there are still sellers on AliExpress pushing aftermarket NMC lithium packs for Prius. We know exactly where that road leads, and you can bet we’ll be covering that story too—when the shit finally hits the fan.

Stay tuned. This is just the beginning of what Sodium-ion can survive.