Olivine structure FePO4
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Overcharge
• LiFePO4 has good safety performance. • Following show 1C/12V overcharge result.
Condition 1C/12V
(V)
Impedance before test
(mΩ)
Phenomena
Result
258#
3.47
Swelling, vent
58.7
open, no fire, Pass
no explosion.
GSM1/0.2C
GSM2/0.2C
1#
90.3%
86.0%
2#
88.9%
84.7%
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High temperature Storage
• Following show storage results of LiFePO4 and LiCoO2 system .
After test
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Fire exposure
• LiFePO4 has good safety performance.
• Following show the fire exposure result.
Cell No.
Voltage before test
LiFePO4
Storage condition
60℃, 7days 85℃, 48hours
Capacity keeping ratio
(capacity after storage / capacity before storage)
85.2%
75.1%
Capacity recovering ratio (capacity after recharge
capacity before storage)
/ capacity before storage)
60℃, 7days 85℃, 48hours
83.1% 72.5%
89.2% 79.3%
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Low temperature discharge
• Following shows discharge of different temperature.
Cell No. 260# 253# 271#
Max temp. Phenomena
117.10℃ 120.05℃ 120.64℃
Swelling, vent open lightly, no fire, no explosion.
Result Pass Pass Pass
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LiFePO4
Charge
Discharge
Olivine structure
Olivine structure
LiFePO4
FePO4
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Discharge curve
• LiFePO4 has the same discharge curve as LiCoO2. • LiFePO4 has the lower MPV (Mid-point voltage) than
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What is LiFePO4?
• LiFePO4 is a new kind of positive material.
• LiFePO4 also has the function that release or receive Li-ion like LiCoO2.
Temp. ratio(%)
60℃/25℃ 45℃/25℃
93.4
98.2
0℃/25℃ 72.6
-10℃/25℃ -20℃/25℃
64.2
45.4
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Cycle life
• LiFePO4 structure keeps
Charge
stable before and after
Overcharge
• Following show 1C/12V overcharge curve and cell photos.
Before test
After test
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Overcharge
• LiFePO4 has good safety performance. • Following show 3C/32V overcharge result.
/ capacity before storage)
92.8%
80.2%
LiCoO2
Storage condition
Capacity keeping ratio Capacity recovering
(capacity after storage / ratio (capacity after recharge
discharge, so it has good
cycle life. • Basing on experience of other
Discharge
projects, LiFePO4 cycle life can be more than 1000.
Olivine structure LiFePO4
LiCoO2. MPV of LiFePO4 is 3.1~3.2V, MPV of LiCoO2 is 3.6~3.7V.
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GSM discharge
• Following shows GSM discharge curve (cut off voltage is 2.8V).
Condition 3C/12V
Cell No. 273#
Max temp. Phenomena
145.44℃
Swelling, vent open lightly, no fire, no explosion.
Result Pass
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Overcharge
• Following show 3C/32V overcharge curve and cell photos.