GB/T 39864-2021 PDF in English
GB/T 39864-2021 (GB/T39864-2021, GBT 39864-2021, GBT39864-2021)
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Electrochemical performance test of lithium manganese oxide -- Test method for the initial specific discharge capacity and the initial efficiency
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Standards related to (historical): GB/T 39864-2021
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GB/T 39864-2021: PDF in English (GBT 39864-2021) GB/T 39864-2021
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.160
CCS H 21
Electrochemical Performance Test of Lithium
Manganese Oxide - Test Method for the Initial Specific
Discharge Capacity and the Initial Efficiency
ISSUED ON: MARCH 9, 2021
IMPLEMENTED ON: OCTOBER 1, 2021
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of
China.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative References ... 4
3 Terms and Definitions ... 4
4 Test Conditions ... 4
5 Reagents or Materials ... 4
6 Instruments and Equipment ... 5
7 Test Procedures ... 6
8 Test Data Processing ... 10
9 Test Report ... 11
Electrochemical Performance Test of Lithium
Manganese Oxide - Test Method for the Initial Specific
Discharge Capacity and the Initial Efficiency
1 Scope
This Standard specifies the test method for the initial specific discharge capacity and
the initial charge and discharge efficiency of lithium manganese oxide as the cathode
material of lithium ion batteries.
This Standard is applicable to the test of the initial specific discharge capacity and the
initial charge and discharge efficiency of lithium manganese oxide as the cathode
material of lithium ion batteries.
2 Normative References
This document does not have normative references.
3 Terms and Definitions
This document does not have terms or definitions that need to be defined.
4 Test Conditions
When there are no special instructions, the various test procedures specified in this
document should be carried out in a drying room (the environmental dew-point
temperature is ≤ -20 °C). For the situation where there is no drying room, the various
test procedures shall be carried out under the following environmental conditions: the
relative humidity is ≤ 40.0% and the temperature is 20 °C ~ 30 °C.
5 Reagents or Materials
5.1 Lithium manganese oxide.
5.2 Conductive agent: acetylene black or carbon black; D50 is 1.0 μm ~ 3.0 μm.
5.3 Polyvinylidene fluoride: abbreviated as PVDF; battery grade; molecular weight ≥ 5
105; rotational viscosity ≥ 6,000 mPa s; moisture content ≤ 0.10%.
6.11 Inert atmosphere (argon) glove box: water vapor and oxygen contents (mass
fraction) are not greater than 0.0005%.
6.12 Insulating tweezers.
6.13 Liquid injector: 1 mL.
6.14 Button battery sealing and packaging machine.
6.15 Lithium-ion battery electrochemical performance testing machine: 5 V/10 mA, with
an accuracy of 0.1%.
6.16 Thermostat: 0 °C ~ 60 °C, with a temperature control accuracy of 0.5 °C.
6.17 Desiccator.
7 Test Procedures
7.1 Pre-treatment of Reagents and Materials
7.1.1 Lithium manganese oxide (5.1), conductive agent (5.2), polyvinylidene fluoride
(5.3): place it into the vacuum oven (6.10); at the temperature of 100 °C, bake for 15
h. Then, place it into the desiccator (6.17) to cool down to room temperature.
7.1.2 Lithium ion battery separator (5.7): place it in the vacuum oven (6.10); at the
temperature of 75 °C ~ 95 °C, bake for 4 h. Then, take it out and transfer it to the inert
atmosphere (argon) glove box (6.11) for storage.
7.1.3 Standard structural components of CR2032 battery (5.9): use ethanol (5.6) to
conduct ultrasonic cleaning on the standard structural components of CR2032 battery
for 3 times, 30 min each time. After the operation is completed, take out the structural
components (5.9) and place them in the vacuum oven (6.10). At 90 °C, dry them for 15
h. Then, transfer them to the inert atmosphere (argon) glove box (6.11) for storage.
7.1.4 Aluminum foil (5.5): use ethanol (5.6) to wipe and clean the aluminum foil.
7.2 Preparation of Cathode Sheet
7.2.1 Glue preparation
In accordance with the mass fraction ratio of 90 : 4 : 6, calculate NMP (5.4), conductive
agent (5.2) and polyvinylidene fluoride (PVDF) (5.3); use the electronic balance (6.2)
for weighing. The operation procedures are as follows:
a) Add the weighed NMP (5.4) to the beaker under the centrifugal diffuser (6.4);
gradually add the weighed polyvinylidene fluoride (5.3); perform dispersive
stirring, until it is completely dissolved;
Where,
c---the compaction density of the cathode sheet, expressed in (g/cm3);
mc---the mass of the cathode sheet, expressed in (g);
mAl---the mass of the aluminum foil substrate, expressed in (g);
---the diameter of the cathode sheet, expressed in (mm);
dc---the thickness of the cathode sheet, expressed in (μm);
dAl---the thickness of the aluminum foil substrate, expressed in (μm).
Use the roller machine (6.9) to roll the baked sheet in 7.2.3. When the compaction
density of the cathode sheet reaches the design value (generally, 2.2 g/cm3 ~ 2.8
g/cm3), stop rolling. Use the sheet-punching machine (6.7) to punch out a sufficient
number of cathode sheets with a diameter of 14 mm; place them in the vacuum oven
(6.10). At 90 °C, bake for 15 h. Then, use the electronic balance (6.3) for weighing.
Calculate the mass (m) of the active substance lithium manganese oxide in the
cathode sheet; number and record it. Transfer to the inert atmosphere (argon) glove
box (6.11) for storage.
7.3 Battery Assembly
Battery assembly shall be carried out in the inert atmosphere (argon) glove box (6.11).
The sequence of the assembly of button batteries, from bottom to top, is: anode shell,
lithium metal sheet, lithium ion battery separator, cathode sheet, gasket, spring support
sheet and anode shell. The specific operations may take the following steps as a
reference:
---Place the anode shell (with the opening facing upwards) flatwise on the surface
of the horizontal platform;
---Use the insulating tweezers (6.12) to pick up the lithium metal sheet (5.8) and
place it into the anode shell; contact the plane of the anode shell and lay flatwise
at the center of the anode shell;
---Use the insulating tweezers (6.12) to pick up the lithium ion battery separator
(5.7), so that it completely covers the lithium metal sheet and is centered;
---Use the liquid injector (6.13) to inject 200 μL of the electrolyte (5.10) into the
anode shell;
---Use the insulating tweezers (6.12) to pick up the cathode sheet prepared in
7.2.4; place it right in the middle of the lithium ion battery separator (5.7);
---Use the insulating tweezers (6.12) to respectively pick up the gasket and the
7.5 Data Record
After one week of the charge and discharge cycle of the test battery, record the charge
and discharge capacity and the mass of the active substance lithium manganese oxide
in the corresponding test battery. Calculate the initial specific discharge capacity and
the initial charge and discharge efficiency of lithium manganese oxide.
8 Test Data Processing
8.1 Initial Specific Discharge Capacity
The initial specific discharge capacity of lithium manganese oxide is calculated in
accordance with Formula (3):
Where,
C---the initial specific discharge capacity, expressed in (mA h/g);
QID---the initial discharge capacity, expressed in (mA h);
m---the mass of the active substance lithium manganese oxide in the test battery,
expressed in (g).
The calculation result shall retain one decimal place.
8.2 Initial Charge and Discharge Efficiency
The initial charge and discharge efficiency of lithium manganese oxide is calculated in
accordance with Formula (4):
Where,
---the initial charge and discharge efficiency;
QID---the initial discharge capacity, expressed in (mA h);
QIC---the initial charge capacity, expressed in (mA h).
The calculation result shall retain one decimal place.
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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