BYD磷酸铁锂电池性能测试

BYD磷酸铁锂电池性能测试

BYD COMPANY LIMITED

LiFePO4 performance

2006-06-211

BYD磷酸铁锂电池性能测试

BYD COMPANY LIMITED

Outline1. 2. 3. 4. 5. 6. 7. 8. What is LiFePO4? Discharge curve GSM discharge High temperature Storage Low temperature discharge Cycle life Overcharge Fire exposure2

BYD磷酸铁锂电池性能测试

BYD COMPANY LIMITED

What is LiFePO4? LiFePO4 is a new kind of positive material. LiFePO4 also has the function that release or receive Li-ion like LiCoO2.ChargeLiFePO4

Discharge

Olivine structure LiFePO4

Olivine structure FePO43

BYD磷酸铁锂电池性能测试

BYD COMPANY LIMITED

Discharge curve LiFePO4 has the same discharge curve as LiCoO2. LiFePO4 has the lower MPV (Mid-point voltage) than LiCoO2. MPV of LiFePO4 is 3.1~3.2V, MPV of LiCoO2 is 3.6~3.7V.

BYD磷酸铁锂电池性能测试

BYD COMPANY LIMITED

GSM discharge Following shows GSM discharge curve (cut off voltage is 2.8V).

GSM1/0.2C 1# 2# 90.3% 88.9%

GSM2/0.2C 86.0% 84.7%5

BYD磷酸铁锂电池性能测试

BYD COMPANY LIMITED

High temperature Storage Following show storage results of LiFePO4 and LiCoO2 system .LiFePO4

Storage condition60℃, 7days

Capacity keeping ratio(capacity after storage / capacity before storage)

Capacity recovering ratio (capacity after recharge/ capacity before storage)

85.2%

92.8%

85℃, 48hoursLiCoO2

75.1%

80.2%

Storage condition 60℃, 7days 85℃, 48hours

Capacity keeping ratio(capacity after storage / capacity before storage)

Capacity recovering ratio (capacity after recharge/ capacity before storage)

83.1% 72.5%

89.2% 79.3%6

BYD磷酸铁锂电池性能测试

BYD COMPANY LIMITED

Low temperature discharge Following shows discharge of different temperature.

Temp.

60℃/25℃

45℃/25℃

0℃/25℃

-10℃/25℃

-20℃/25℃

ratio(%)

93.4

98.2

72.6

64.2

45.47

BYD磷酸铁锂电池性能测试

BYD COMPANY LIMITED

Cycle life LiFePO4 structure keeps stable before and after discharge, so it has good cycle life. Basing on experience of other projects, LiFePO4 cycle life can be more than 1000.Charge

Discharge

Olivine structure LiFePO4

Olivine structure FePO4

BYD磷酸铁锂电池性能测试

BYD COMPANY LIMITED

Overcharge LiFePO4 has good safety performance. Following show 1C/12V overcharge result.

Condition

Cell No. 260#

Max temp. 117.10℃ 120.05℃ 120.64℃

Phenomena Swelling, vent open lightly, no fire, no explosion.

Result Pass Pass Pass

1C/12V

253# 271#

BYD磷酸铁锂电池性能测试

BYD COMPANY LIMITED

Overcharge Following show 1C/12V overcharge curve and cell photos.Before test

After test

BYD磷酸铁锂电池性能测试

BYD COMPANY LIMITED

Overcharge LiFePO4 has good safety performance. Following show 3C/32V overcharge result.

Condition

Cell No.

Max temp.

Phenomena Swelling, vent open lightly, no fire, no explosion.

Result

3C/12V

273#

145.44℃

Pass

BYD磷酸铁锂电池性能测试

BYD COMPANY LIMITED

Overcharge Following show 3C/32V overcharge curve and cell photos.After test

BYD磷酸铁锂电池性能测试

BYD COMPANY LIMITED

Fire exposure LiFePO4 has good safety performance. Following show the fire exposure result.Cell No. Voltage before test (V) Impedance before test (mΩ) Phenomena Result

Before test

After test

258#

3.47

58.7

Swelling, vent ope

n, no fire, no explosion.

Pass

268#

3.43

52.8

251#

3.58

56.0

Swelling, vent open, fire, no explosion.

Pass

Pass

BYD磷酸铁锂电池性能测试

BYD COMPANY LIMITED