Yuasa is mostly known for motorcycle batteries. Last I heard they were determined to be off the hook and Boeing's electronics were suspect.

There may be a lot of cross-finger-pointing, but it's hard to see how the Boeing electronics would make the batteries catch fire. One would think that that's the battery manufacturer's responsibility. Whatever -- Boeing picked this supplier and is going to wallow in some deep kim chee. As are some honchos at the FAA.

Lithium Ion batteries are tricky in they take a lot of electronics like this inside each cell:
Shut-down separator (for over temperature)
Tear-away tab (for internal pressure)
Vent (pressure relief)
Thermal interrupt (over current/overcharging)

Then they take special chargers particularly when they have multiple cells. In the "before" battery pictures you can see all the control circuit boards. The recharge (Boeing side) will also have a lot of complicated charging circuitry and programming.

What could go wrong? #challenger

The before after pic I mentioned above:
http://a57.foxnews.com/global.fncstatic.com/static/managed/assets/0/371/BoeingFireBattery.jpg

Note the circuit board for the cells at the top of the Right side box. Also through the milky shield you can see the Thermal interrupt between the cells.
The charging takes a "smart circuit"
Stage 1:
CC: Apply charging current to the battery, until the voltage limit per cell is reached.
Stage 2:
Balance: Reduce the charging current (or cycle the charging on and off to reduce the average current) while the state of charge of individual cells is balanced by a balancing circuit, until the battery is balanced.
Stage 3:
CV: Apply a voltage equal to the maximum cell voltage times the number of cells in series to the battery, as the current gradually declines asymptotically towards 0, until the current is below a set threshold of about 3% of initial constant charge current.

Faulty electronics can overcharge these type of batteries and cause some serious overheating. Or, defective batteries can just seriously overheat themselves. Either way, it's not good for Boeing.

I once watched a NOVA on PBS about a Boeing 737 that broke up at high altitude and high speed over the Panama jungle. The NTSB investigation eventually determined that the pilot unknowingly destroyed his own plane because a single wire inside a wiring harness in the airframe had flexed too many times until it broke and fed him false information, and no one on board felt a thing until the plane fell apart due to the complex physics involved.

I never felt the same about flying ever since.

Copa Flight 201

Rushed?

That plane is 3 years behind schedule

I don't think Boeing's global manufacturing idea is panning out

Time to bring the plane manufacturing back to Everett

Yes, just think how much safer you all would be if Boeing built its own engines, manufactured its own tires, smelted its own aluminum, produced its own radar and radios, made its own windshields and fabricated its own wire. And we know those Japanes, they have absolutely no history, experience and success in battery design and production. It's only a bunch of lawyers sitting at the FAA and NTSB in southwest Washington DC who will be able to get it all this right.

I'd rather trust Boeing than the Japanese to produce nuclear power upwind from me. They seem to have some problems with electrical systems.

"Whatever -- Boeing picked this supplier"

Actually, Boeing didn't. One of Boeing's genius moves on the 787 program was to identify about twenty prime contractors for the various systems on the aircraft, and then made the prime contractors responsible for finding subcontractors and managing quality control associated with those subcontractors. It made managing the project a lot simpler (and cheaper) for Boeing, but ignored the fact that Boeing is responsible for the whole aircraft - they can't fob off responsibility onto a contractor.

Actually, Randomx, that array of prime contractors did not make managing the project either cheaper, easier or faster. I posted a good short clear link on this "genius" creation of the Boeing/McDonnell Douglas merger yesterday.