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Samsung Note 7 battery explosion investigation report

After months of silence following a global recall of its Galaxy Note 7 smartphone last October, Samsung disclosed its lengthy findings as to what caused the device’s batteries to overheat and catch fire. Based on the company’s own investigation and independent scientific analysis of the issues by three consulting bodies, the overheating was caused by separate problems in batteries sourced from two different suppliers.



In the case of batteries sourced from A (Samsung SDI), there wasn’t enough room between the heat-sealed protective pouch around the battery and its internals. In the worst scenarios, that caused electrodes inside each battery to crimp, weaken the separator between the electrodes, and cause short circuiting.
 
In the case of batteries sourced from B  (Amperex Technology Limited), some cells were missing insulation tape, and some batteries had sharp protrusions inside the cell that led to damage to the separator between the anode and cathode. The batteries also had thin separators in general, which increased the risks of separator damage and short circuiting.



The findings were announced after testing 200,000 devices and 30,000 batteries in a giant charging and recharging test facility built for the task. Samsung mobile communications chief D.J. Koh says a team of 700 company engineers conducted internal testing, and independent reviews of potential problems were carried out by UL, Exponent, and TÜV Rheinland.

The company offered this explanation at a press event in South Korea Sunday. Samsung did not provide details about its prior quality-control procedures, but the company says it has overhauled its safety testing process as a result of the investigations.

“We are taking responsibility for our failure to identify the issues arising out of the battery design and manufacturing process prior to the launch of the Note 7,” Koh said at the conclusion of the event.

Q&A on press conference

電池問題與趕工有關嗎?

作為流動設備生產商之一,當然希望越早為消費帶來新產品就越好,當然就被問到出現問題是否與 Apple 推出 iPhone 7 有關?關於這一點,Samsung 表示他們一直以來都以客戶的使用體驗及安全作為大前題,並沒有因為要趕於對手發布新產品前而趕工出貨。當首批產品出現問題後,亦沒有因此而向另一間電池生產商施壓,造成今次問題的主要原因只是電池本身的問題。( doubtful)

機身太簿電池容量太大造成問題?

從報告可以看到,電池出現問題的其中一個原因是出現變型及損壞,因此亦被問到是否與 Note 7 由於要保留纖薄體積加上電池容量增加而令電池的安裝困難度提升。從 Samsung 找來獨立研究公司所作出的測試,分別將電池作「裸跑」和安裝在 Note 7 內作模擬測試,結果發現出現問題的比例相若,因此排除了因安裝過程而令電池出現變型或損壞的原因。另一個早前被猜測導致電池出現問題的原因,是否因 Note 7 的電池容量增加至 3,500mAh 有關呢?而經過獨立研究機構的測試,證實電池容量絕非是今次一連串意外的(唯一)成因。






Before announcing the findings, DJ Koh, president of Samsung Mobile, said, "I deeply apologize to all of our customers, carriers, retail and distribution partners, and all of our business partners." So far, Samsung has admitted to a $5 billion loss in profits due to the widespread recall and cancellation of the Galaxy Note 7, with analysts estimating the revenue loss at $10 billion.

Samsung press conference

reports from separate third party consultants:

UL MUST READ
TUV Rheinlard
Exponent

Future improvements:


from wired, unwire , cnet,  , softpedia  , and ars technica

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