Answer type: Group answers ( 4–5 members ).

Scoring:

• +1 point per correct answer.

• +0.5 bonus if group explains their reasoning.

• -0.5 if group copies another team’s answer without explanation.

Q1. What was the main technical cause of the Galaxy Note 7 fires?

A. Internal short circuit in the battery

B. Screen overheating

C. Charger malfunction

D. Software bug

Q2. Which component was found to be unusually thin and contributed to safety risks?

A. Cathode material

B. Anode foil

C. Separator layer

D. Aluminium tab

Q3. Name one manufacturing defect reported in Note 7 batteries.

A. Welding burrs on electrode tabs

B. Missing insulating tape

C. Poor component alignment

D. All of the above

Q4. What safety mechanism did Samsung use after recall to prevent charging?

A. Automatic shutdown

B. Over-the-air software patch limiting battery capacity

C. Replacement charger

D. Metal casing

Q5. What key lesson for industry does this case highlight?

A. Faster release is more important than testing

B. Energy density should always be maximized

C. Independent and thorough battery testing is essential

D. Customers do not care about recalls

Q2 — C. Separator layer
Explanation: The separator was unusually thin (<5 µm) and prone to tearing or delamination. A damaged separator allows electrodes to touch and causes an internal short.

Q3 — D. All of the above
Explanation: Investigations reported multiple manufacturing defects: welding burrs on electrode tabs, missing insulating tape, and poor component alignment — all of which can create punctures or shorting points in a cell.

Q4 — B. Over-the-air software patch limiting battery capacity
Explanation: Samsung issued an OTA software update to limit maximum charge (reduce state of charge) as an emergency mitigation. This reduced available energy but did not fix the underlying cell defects.

Q5 — C. Independent and thorough battery testing is essential
Explanation: The key industry lesson is the necessity of rigorous, independent battery testing and strict quality control to catch edge-case failure modes before mass production.

Đỗ Nhật Hạ

Nguyễn Trung Nghị

Võ Ngọc Bảo Ngân

Vũ Thị Bảo Trâm

1A 2C 3D 4B 5C

2. Which component was found to be unusually thin and contributed to safety risks?
C. Separator layer
(Samsung used ultra-thin <5 µm separators vs. safer multilayer ~25 µm.)

3. Name one manufacturing defect reported in Note 7 batteries.
D. All of the above
(Welding burrs, missing insulating tape, poor alignment all contributed.)

4. What safety mechanism did Samsung use after recall to prevent charging?
B. Over-the-air software patch limiting battery capacity
(Samsung pushed software to cap charging and later disable Note 7s.)

5. What key lesson for industry does this case highlight?
C. Independent and thorough battery testing is essential
(Rushed design/testing without redundancy led to catastrophic failure.)

Q2: The correct answer is C. Separator layer because Samsung used ultra-thin separators under 5 µm, which were far weaker than standard multilayer separators of about 25 µm.

Q3: The correct answer is D. All of the above because the investigation revealed multiple manufacturing defects, including welding burrs, missing insulating tape, and poor component alignment.

Q4: The correct answer is B. Over-the-air software patch limiting battery capacity because Samsung sent updates that restricted charging to reduce fire risks and eventually made charging impossible.

Q5: The correct answer is C. Independent and thorough battery testing is essential because Samsung rushed to compete with Apple, overlooked proper testing, and failed to detect critical design flaws.

Q2: The correct answer is C. Separator layer because Samsung used ultra-thin separators under 5 µm, which were far weaker than standard multilayer separators of about 25 µm.

Q3: The correct answer is D. All of the above because the investigation revealed multiple manufacturing defects, including welding burrs, missing insulating tape, and poor component alignment.

Q4: The correct answer is B. Over-the-air software patch limiting battery capacity because Samsung sent updates that restricted charging to reduce fire risks and eventually made charging impossible.

Q5: The correct answer is C. Independent and thorough battery testing is essential because Samsung rushed to compete with Apple, overlooked proper testing, and failed to detect critical design flaws.

Q2: The correct choice is C. Separator layer, since Samsung used separators thinner than 5 μm, which were much weaker compared to the standard multilayer separators of around 25 μm.

Q3: The correct choice is D. All of the above, as the investigation found several manufacturing flaws, such as welding defects, missing insulation tape, and poor alignment of components.

Q4: The correct choice is B. Over-the-air software patch limiting battery capacity, because Samsung issued updates that restricted charging to reduce fire hazards, eventually preventing charging altogether.

Q5: The correct choice is C. Independent and thorough battery testing is essential, as Samsung hurried to compete with Apple, skipped adequate testing, and overlooked major design flaws.

C
The document highlights that the separator is an unusually thin single layer, prone to delamination and short circuits, increasing safety risks by failing to prevent electrode contact.

D
The document and Samsung’s probe report multiple defects: welding burrs on electrode tabs causing pinching, missing or poor-quality insulating tape, and misalignment in tightly folded areas—all contributing to short circuits.

B
Samsung implemented OTA updates to initially cap battery charging at 60%, then reduce it to 0%, to prevent overheating and further incidents, as confirmed by official findings.

C
This case emphasizes the need for rigorous, independent testing to detect design and manufacturing flaws early. Kodak’s reluctance to innovate demonstrates that skipping thorough validation can lead to widespread failures and recalls.

2C
The document highlights that the separator is an unusually thin single layer, prone to delamination and short circuits, increasing safety risks by failing to prevent electrode contact.

3D
The document and Samsung’s probe report multiple defects: welding burrs on electrode tabs causing pinching, missing or poor-quality insulating tape, and misalignment in tightly folded areas—all contributing to short circuits.

4B
Samsung implemented OTA updates to initially cap battery charging at 60%, then reduce it to 0%, to prevent overheating and further incidents, as confirmed by official findings.

5C
This case emphasizes the need for rigorous, independent testing to detect design and manufacturing flaws early. Kodak’s reluctance to innovate demonstrates that skipping thorough validation can lead to widespread failures and recalls.

Q2. The unusually thin component that contributed to safety risks was:
C. Separator layer
Reasoning: The separator was too thin, making it easier for positive and negative layers to short-circuit.

Q3. One manufacturing defect reported in Note 7 batteries was:
D. All of the above (welding burrs, missing tape, poor alignment)
Reasoning: Multiple quality issues combined increased the risk of thermal runaway.

Q4. The safety mechanism Samsung used after recall to prevent charging was:
B. Over-the-air software patch limiting battery capacity
Reasoning: Samsung pushed software updates to limit charging (first 60%, then 30%, eventually disabling use).

Q5. The key lesson for industry from this case is:
C. Independent and thorough battery testing is essential
Reasoning: Rushing to market without complete safety validation can cause catastrophic failures and brand damage.

2. Answer: C. Separator layer
The paper states the separator was "unusually thin" and "thinner compared with others," which increased the risk of a short circuit.

3. Answer: D. All of the above
The paper mentions all the listed defects: welding burrs, missing insulating tape, and poor component alignment.

4. Answer: B. Over-the-air software patch limiting battery capacity
The paper states Samsung launched an "over-the-air safety software patch" to "limit the extent to which the phone could be charged."

5. Answer: C. Independent and thorough battery testing is essential
The conclusion implies that the rush for performance led to design compromises, highlighting the importance of "test and development methods to control such risks."

Q2. The unusually thin component that contributed to safety risks was:
C. Separator layer
Reasoning: Because the separator was made too thin, it increased the chance of the positive and negative layers coming into contact and shorting out.

Q3. One manufacturing defect reported in Note 7 batteries was:
D. All of the above (welding burrs, missing tape, poor alignment)
Reasoning: A combination of multiple production flaws raised the likelihood of thermal runaway incidents.

Q4. The safety mechanism Samsung used after recall to prevent charging was:
B. Over-the-air software patch limiting battery capacity
Reasoning: Samsung released updates that progressively restricted charging levels—first to 60%, then 30%, and eventually disabling the device.

Q5. The key lesson for industry from this case is:
C. Independent and thorough battery testing is essential
Reasoning: Launching a product without adequate safety verification can result in serious failures and long-term reputational harm.

A. Internal short circuit in the battery

B. Screen overheating

C. Charger malfunction

D. Software bug

==> Reason: The batteries had internal short circuits due to design and manufacturing flaws, leading to overheating and fires.

Q2. Which component was found to be unusually thin and contributed to safety risks?

A. Cathode material

B. Anode foil

C. Separator layer

D. Aluminium tab

==> Reason: The separator, which prevents contact between the positive and negative electrodes, was too thin and prone to failure.

Q3. Name one manufacturing defect reported in Note 7 batteries.

A. Welding burrs on electrode tabs

B. Missing insulating tape

C. Poor component alignment

D. All of the above

==> Reason: Defects included welding burrs, missing insulation tape, and poor component alignment—each could cause short circuits.

Q4. What safety mechanism did Samsung use after recall to prevent charging?

A. Automatic shutdown

B. Over-the-air software patch limiting battery capacity

C. Replacement charger

D. Metal casing

==> Samsung released a software update that reduced maximum charging capacity to minimize fire risks.

Q5. What key lesson for industry does this case highlight?

A. Faster release is more important than testing

B. Energy density should always be maximized

C. Independent and thorough battery testing is essential

D. Customers do not care about recalls

==> Reason: The incident showed that rushing products without sufficient safety testing can lead to catastrophic failures.

Q2. Which component was found to be unusually thin and contributed to safety risks?
Answer: C. Separator layer
Explanation: The separator (the thin layer that keeps the positive and negative electrodes apart) was too thin, making it fragile and more likely to fail, which increased the risk of short circuits.

Q3. Name one manufacturing defect reported in Note 7 batteries.
Answer: D. All of the above
Explanation: Investigations found multiple manufacturing problems, including welding burrs on electrode tabs, missing insulating tape, and poor alignment of components. Together, these defects made the batteries unstable.

Q4. What safety mechanism did Samsung use after recall to prevent charging?
Answer: B. Over-the-air software patch limiting battery capacity
Explanation: After the recall, Samsung issued an OTA software update that limited how much the battery could be charged (eventually reducing it to 0%), preventing further risks while customers returned their devices.

Q5. What key lesson for industry does this case highlight?
Answer: C. Independent and thorough battery testing is essential
Explanation: The rush to release the phone and insufficient testing caused catastrophic failures. The main lesson is that independent and rigorous battery testing must always be done before launch.

Q2. The unusually thin component that heightened safety concerns was:
C. Separator layer
Explanation: Because the separator was extremely thin, it made it easier for the positive and negative electrodes to come into contact and short-circuit.

Q3. A reported manufacturing defect in Note 7 batteries was:
D. All of the above (welding burrs, missing insulation tape, misalignment)
Explanation: A combination of multiple quality flaws significantly raised the probability of thermal runaway.

Q4. The safety measure Samsung implemented after the recall to prevent further charging was:
B. Over-the-air software patch limiting battery capacity
Explanation: Samsung released software patches that progressively limited charging capacity (first to 60%, then 30%, and eventually disabled the device completely).

Q5. The most important industry lesson from this incident is:
C. Independent and thorough battery testing is essential
Explanation: Accelerating product launches without thorough safety validation can result in catastrophic failures and severe brand damage.

Q2: The correct option is C. Separator layer, since Samsung applied ultra-thin separators of less than 5 μm, which were significantly weaker than the standard multilayer separators measuring about 25 μm.

Q3: The correct option is D. All of the above, as the investigation uncovered several production flaws such as welding burrs, missing insulation tape, and misaligned components.

Q4: The correct option is B. Over-the-air software patch limiting battery capacity, because Samsung released updates that gradually reduced charging capacity to minimize fire hazards until charging was no longer possible.

Q5: The correct option is C. Independent and thorough battery testing is essential, since Samsung, in its haste to compete with Apple, neglected proper safety testing and overlooked major design weaknesses.