How Much Energy Is In A Battery?

 

Recently I posted about Samsung’s engineering errors concerning the Note Seven.  Well somebody has taken one apart and it’s worse than I thought.

https://tech.slashdot.org/story/16/12/05/2032203/engineers-explain-why-the-galaxy-note-7-caught-fire

While we were doing the teardown, Sam wondered, “Samsung engineers are smart.  Why would they design it like this?” The answer isn’t a mystery: innovation means pushing the boundaries.  For something that is innovative and new, you design the best tests that you can think of, and validate that the design is okay through that testing.  Battery testing takes a notoriously long time (as long as a year for certain tests), and thousands of batteries need to be tested to get significant results.  It’s possible that Samsung’s innovative battery manufacturing process was changing throughout development, and that the newest versions of the batteries weren’t tested with the same rigor as the first samples.

If the Galaxy Note 7 wasn’t recalled for exploding batteries, Sam and I believe that a few years down the road these phones would be slowly pushed apart by mechanical battery swell.  A smaller battery using standard manufacturing parameters would have solved the explosion issue and the swell issue.  But, a smaller battery would have reduced the system’s battery life below the level of its predecessor, the Note 5, as well as its biggest competitor, the iPhone 7 Plus.  Either way, it’s now clear to us that there was no competitive salvageable design.

The design and validation process for a new product is challenging for everyone.  In this case, Samsung took a deliberate step towards danger, and their existing test infrastructure and design validation process failed them.  They shipped a dangerous product.  That this is possible at one of the top consumer electronic companies in the world is humbling — and demonstrates the need for better tools.  Instrumental is building them.

Looking at the gaps in the pictures in the report, I’m asking myself, “what were they thinking?” There’s pushing the envelope and just plain stupid.  It looks to me as if just plain stupid won this one.  Which is not a good thing to do when you are dealing with a battery that is a high energy cell.  How much energy? Well let’s see.

Thunderfoot has a couple of videos explaining just how much energy is in batteries that might just be more dangerous than you might think. Enough to make Dirty Harry’s Cannon look like a peashooter.

Enough to carry a person for miles.

It’s a testament to battery engineers and the amount of testing they did that the Li ion battery is considered so safe that nobody concerns themselves very much with them when they put them right next to themselves like the computer I’m writing this on or even right next to their heads, in a cellphone. Still those things do carry a lot of energy in a fairly concentrated form. Also the typical Li ion battery is not encased in a drawn metal case like the batteries that I grew up with.

https://en.wikipedia.org/wiki/Lithium-ion_battery

http://batteryuniversity.com/learn/article/lithium_based_batteries

There’s also the fact that lithium is far more reactive than the alkaline battery compounds typically used in batteries and the cases need to be able to expand during recharging to deal with the heat.  otherwise you get things like this.

And this.

https://www.wired.com/2016/10/samsung-isnt-one-lithium-ion-problems-just-ask-nasa/

The problem is never how much energy you have in a system, but how you manage it and the potential problems that arise.  You really don’t want phones exploding beside people’s heads.

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