The causes of Samsung's exploding phones finally revealed

After months of study with more than 700 investigators  on the case, Samsung came to the obvious conclusion: Battery defects caused its Galaxy Note 7 phones to overheat.  So  what was the real news announced Monday morning at the company's news conference in Seoul?  Samsung Mobile laid out specifics, admitting that it had not been on top of quality control and saying it would be far more proactive in the future.

With the original batch of Galaxy Note 7 phones, the casing pouch surrounding the battery was found to be too tight, leaving too little space for the battery to expand and contract when going through charge and discharge cycles.

As a result, positive and negative electrodes touched, short-circuiting the battery. While the company did not share the name of the battery maker, the U.S. Consumer Product Safety Commission reported that the batteries were sourced from sister company Samsung SDI.

For the replacement phones that Samsung then served up to consumers, the company turned to another battery supplier, identified  by the product safety commission as  Hong Kong-based Amperex Technology. Hard-pressed to crank out 10 million replacements, the maker allowed welding errors to go unchecked, Samsung said Monday. Hanging bits of solder caused some batteries to short-circuit.

To shore up both its reputation and that of lithium ion batteries in general, Samsung will now handle quality control of  batteries internally, rather than relying on its suppliers to do so, and will institute an eight-point inspection process including X-rays and accelerated use testing. A Samsung spokesman said the company was sharing its new battery review process with global standards groups and hoped others would adopt it to avoid more dangerous and brand-damaging incidents.

Lithium ion batteries have also been blamed for flare-ups of  laptop computers and electric scooters, though some makers of the latter have said "poor battery management"  sparked  overcharging  problems with the  ride-ons.

Samsung's  concessions followed another embarrassing  hot-potato problem and "chill-out" for the company.  Last week, a South Korean court blocked state prosecutors' attempts to arrest Samsung chief Jay Y. Lee on bribery charges. The court decided there was  too little evidence that  Lee had contributed  a reputed $36 million to  a charity associated with South Korean President Park Geun-hye to ease his merger of companies and his accession to leadership of the family-run conglomerate, South Korea's biggest.

Park has already been impeached for squeezing huge donations from a number of other South Korean concerns.