The Safety level of Lithium Metal Coin Cells 9 th -11 th September - - PowerPoint PPT Presentation

The Safety level of Lithium Metal Coin Cells

9th -11th September 2014

• 1. Structure of the lithium metal coin cell
• 2. Test outline for external & internal short circuit

(UN T-5 & T-6)

• 3. The Safety level of Japanese coin cells

(Already reported data)

• 4. The Safety level of coin cells collected worldwide

(A new report)

Coin (Button)： Large electric current does not flow because of small electrode area.

• 1. Structure of the lithium metal coin cell

Gasket Separator Manganese dioxide Lithium Positive terminal Negative terminal

2-1. Test outline of External short circuit (UN T-5)

■Test Condition ・Unused cell (Fresh) ・Atmosphere: 55±2℃ ・Circuit Resistance：<0.1Ω ■Requirements ・Temp. of cell : <170℃ ・No Explosion , No Rupture , No Fire This test is based on UN Manual of Tests and Criteria 5th revised edition Amendment 1, PartⅢ subsection 38.3.

Thermostat Chamber

2-2. Test outline of Crush (UN T-6)

■Test Condition ・Unused cell (Fresh) ・Crush Speed:1.5cm/s ・Continue until either;

• Pressure：13±0.78kN
• Drop of Voltage :>100mV
• Compressibility:>50%

■Requirements ・Temp. of cell : <170℃ ・No Explosion, No Fire This test is based on UN Manual of Tests and Criteria 5th revised edition Amendment 1, PartⅢ subsection 38.3. This test simulates mechanical abuse from a crush that can result in an internal short circuit.

Test

UN-T5

External short circuit

UN-T6

Crush 55±2℃ 20±5℃

CR2032

made by Japanese manufacturers Results No Explosion No Fire No Explosion No Fire MAX Temp. 58～60℃ (+5℃ increase) Less than 30 ℃ (+10℃ increase)

• 3. External ＆ Internal short circuit (Japanese cells)

As large electric current does not flow in a coin battery, temperature does not increase in most cases, therefore self-ignition does not happen.

13kN < 0.1Ω

CR2477 CR2450 CR2032 Amount of Li 0.29g 0.18g 0.06g The number of models made by Japanese manufacturers 2 3 3 The number of models made by

• ther countries’ manufacturers

5 19 28 Total 7 22 31 The most common CR type (Li/MnO2) lithium metal coin cells were collected worldwide to evaluate the safety level. These were purchased through the open market (shop, internet ,etc.) from around the world. CR2477 has the highest capacity, CR2032 is the most popular size.

4-1. Lithium Metal Coin Cells Collected Worldwide

Every cell was assigned a sample number according to the brand and manufacturer.

20 30 40 50 60 70 80 10 20 30 40 50 60 Temperature(degree C) Time(min)

CR2477(Li 0.29g)_55℃

No.24 No.30 No.31 No.32 No.54 JPN-A JPN-C

4-2. Test Results of External Short Circuit (Worldwide collected CR2477(Li 0.29g))

Temperature of every cell increased within 10℃ , and below 170℃. Neither explosion, rupture or fire were observed.

4-3. Test Results of External Short Circuit (Worldwide collected CR2477,CR2450,CR2032)

CR2477(Li 0.29g) CR2450(Li 0.18g) CR2032(Li0.06g) at 55℃ (T-5) Not evaluated at RT

Temperature of every cell increased within 10℃ , and below 170℃. Neither explosion, rupture or fire were observed.

20 30 40 50 60 70 80 10 20 30 40 50 60 Temperature(degree C) Time(min)

CR2450(Li 0.18g)_55℃

No.19 No.21 No.22 No.23 No.24 No.25 No.26 No.27 No.28 No.29 No.30 No.31 No.33 No.34 No.35 No.52 No.53 No.54 JPN-A JPN-B

20 30 40 50 60 70 80 10 20 30 40 50 60 Temperature(degree C) Time(min)

CR2477(Li 0.29g)_55℃

No.24 No.30 No.31 No.32 No.54 JPN-A JPN-C

20 30 40 50 60 70 80 10 20 30 40 50 60 Temperature(degree C) Time(min)

CR2477(Li 0.29g)_RT

No.30 No.31 No.32 No.54 JPN-A JPN-C

20 30 40 50 60 70 80 10 20 30 40 50 60 Temperature(degree C) Time(min)

CR2450(Li 0.18g)_RT

No.19 No.21 No.22 No.23 No.24 No.25 No.26 No.27 No.28 No.29 No.30 No.31 No.33 No.34 No.35 No.52 No.53 No.54 JPN-A JPN-C

20 30 40 50 60 70 80 10 20 30 40 50 60 Temperature(degree C) Time(min)

CR2032(Li 0.06)_RT

4-4. Test Results of Crush (Worldwide collected CR2477(Li 0.29g))

Temperature of every cell increased within 10℃ , and below 170℃. Neither explosion or fire were observed.

15 20 25 30 35

• 10

10 20 30 40 50 60 Temperature (°C) Time (min)

CR2477(Li 0.29g) _ Crush

No.24 No.30 No.31 No.32 No.54 JPN-A

Each cell was crushed to 13kN.

CR2450(Li 0.18g) CR2032(Li 0.06g)

4-5. Test Results of Crush (Worldwide collected CR2450,CR2032)

Temperature of every cell increased within 10℃ , and below 170℃. Neither explosion or fire were observed.

Each cell was crushed to 13kN.

15 20 25 30 35

• 10

10 20 30 40 50 60 Temperature(℃) Time(min.)

CR2032(Li 0.06g) _ Crush

No.1 No.2 No.3 No.4 No.5 No.6 No.7 No.8 No.9 No.10 No.11 No.13 No.14 No.15 No.16 No.17 No.18 No.19 No.20 No.21 No.22 No.23 No.24 No.33 No.35 No.51 No.52 No.53 JPN-A JPN-B

15 20 25 30 35

• 10

10 20 30 40 50 60 Temperature(℃) Time(min.)

CR2450(Li 0.18g) _ Crush

No19 No21 No22 No23 No24 No25 No26 No27 No28 No29 No30 No31 No33 No34 No35 No52 No53 No54 JPN-A

Conclusions

Lithium metal coin cells collected worldwide made by

• ther countries' manufactures showed the same safety

level as Japanese coin cells. A lithium metal coin cell does not create high temperature by itself, and does not reach thermal runaway by itself.