I tested a solid-state portable battery for a week – now lithium-ion feels old school

BMX SolidSafe 5K power bank

ZDNET's key takeaways

• This is a 5,000mAh wireless power bank powered by a solid-state cells
• Solid-state cells are far less likely to catch on fire than lithium-ion batteries
• At $80, this is a very expensive unit, so it is focused on those who value safety.

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I've tested countless power banks over the years, and they have all made use of lithium-ion batteries. These have the advantage of being cheap and have high energy density, but they can, if provoked too much, burst into flames. Needless to say, that's not a good thing.

This is where solid-state cells come into play. These ditch the flammable electrolyte solution found in lithium-ion batteries for a non-flammable solid.  

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This is what BMX has done with the SolidSafe 5K power bank. 

This 5,000mAh/19Wh wireless charging power bank is perfectly designed to fit the iPhone. It measures 4.0 x 2.7 x 0.4 in/102.7 x 68 x 11 mm and weighs 4.8 oz/137 g. The magnetic wireless charger is built to Qi2 standards, which means that it can output up to 15W of power for a fast charge. 

The magnets are also strong enough to securely hold the charger to the phone when in use.

There's also a single USB-C port that handles charging (maximum output of up to 20W, maximum input of up to 15W), and it can run alongside the wireless charging pad at up to 15W. The power bank also supports pass-through charging, so it can be charged via USB-C while it's wirelessly charging a phone. I like this feature because I can use a single-outlet charger when traveling light to charge both my iPhone and my power bank overnight. 

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There's a button on the power bank to activate it, and a color display that shows power levels and charging/discharging power. The display is nice and clear, and contains all the information you need. 

This definitely adds to the power bank's quality feel.

The power bank comes with a lanyard that doubles as a USB-C-to-USB-C cable. This is a nice touch because there's a fighting chance that you'll have a cable when you need it.

The SolidSafe 5K is part of a bigger ecosystem of devices. BMX also offers a larger SolidSafe 10K with a 10,000 mAh capacity, along with 3-bay and 5-bay docks for charging multiple power banks. 

How safe are solid-state cells? There was only one way to find out — take the power bank apart and abuse the fully-charged pack by using a screwdriver to make holes in it. 

DON'T TRY THIS AT HOME!

I took precautions of wearing safety glasses and doing the stabbing outside, but as I expected it was thankfully anticlimactic, and the cells merely emitted a few puffs of smoke. 

ZDNET's buying advice

The BMX SolidSafe 5K isn't cheap; it retails for $79.99 (the 10,000mAh version is $99.99, and the 3-bay and 5-bay docking stations are $49.99 and $69.99, respectively). That's more expensive than most power banks of its size.

But it's also new to the field, and I expect prices to come down as this technology becomes more mainstream (although given how cheap and energy-dense lithium-ion batteries are, solid-state batteries are unlikely to replace them any time soon). 

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But if you're after a power bank that's got a low chance of going bad on you — perhaps you travel a lot, or carry one when biking/motorcycling, or are a first responder — this is definitely worth a look.