EastMids:
Japan probe finds miswiring of Boeing 787 battery
If this is the case (and not a non-tech reporter's mis-stating the problem), its not a battery subsystem problem. Its a Boeing QA problem.
I was there back when the FAA came in following QA and configuration control problems with the 757, 737 and others. It wasn't a pretty sight. I hope Boeing didn't throw out the baby with the bathwater after all the work we put in rescuing Boeing's production certificate. One can find and fix a problem once and be forgiven. Make the same mistake again and people will start wondering if they are really up to the job. The whole self certification and production inspection might have to be revisited, with the solution being FAA inspectors on site signing off each plane.