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GB/T 38823-2020 (GBT38823-2020)

GB/T 38823-2020_English: PDF (GBT 38823-2020, GBT38823-2020)
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BASIC DATA
Standard ID GB/T 38823-2020 (GB/T38823-2020)
Description (Translated English) Silicon-carbon
Sector / Industry National Standard (Recommended)
Classification of Chinese Standard Q50
Classification of International Standard 29.050
Word Count Estimation 18,198
Date of Issue 2020-06-02
Date of Implementation 2020-12-01
Drafting Organization Betterray New Materials Group Co., Ltd., Huizhou Dingyuan New Energy Technology Co., Ltd., Guolian Automobile Power Battery Research Institute Co., Ltd., Shenzhen Snow Industrial Development Co., Ltd., Metallurgical Industry Information Standards Research Institute
Administrative Organization National Steel Standardization Technical Committee (SAC/TC 183)
Proposing organization China Iron and Steel Association
Issuing agency(ies) State Administration for Market Regulation, National Standardization Administration

Standards related to: GB/T 38823-2020

GB/T 38823-2020
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 29.050
Q 50
Silicon-carbon
硅炭
ISSUED ON: JUNE 02, 2020
IMPLEMENTED ON: DECEMBER 01, 2020
Issued by: State Administration for Market Regulation;
Standardization Administration of the PRC.
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Normative references ... 4 
3 Terms and definitions ... 5 
4 Classification and code ... 5 
5 Technical requirements ... 6 
5.1 Appearance ... 6 
5.2 Physical and chemical indicators ... 6 
6 Test methods ... 7 
6.1 Appearance ... 7 
6.2 Particle size distribution ... 7 
6.3 Specific surface area ... 7 
6.4 Tap density ... 7 
6.5 Carbon content ... 7 
6.6 Silicon content ... 7 
6.7 Compaction density ... 7 
6.8 Moisture content ... 7 
6.9 Magnetic impurities ... 7 
6.10 Content of trace metal elements ... 7 
6.11 Initial discharge specific capacity and initial coulombic efficiency ... 7 
6.12 Regulated substances ... 7 
7 Inspection rules ... 8 
7.1 Sampling method ... 8 
7.2 Inspection classification ... 8 
7.3 Acceptance rules ... 9 
8 Packaging, marking, storage, and transportation ... 9 
8.1 Packaging ... 9 
8.2 Marking ... 9 
8.3 Storage and transportation ... 10 
Appendix A (Normative) Determination method of carbon content ... 11 
Appendix B (Normative) Determination method of silicon content ... 14 
Appendix C (Normative) Determination method for the content of trace metal elements
... 17 
Appendix D (Normative) Determination method of initial discharge specific capacity
and initial coulombic efficiency ... 20 
Silicon-carbon
1 Scope
This Standard specifies the terms and definitions, classification and code, technical
requirements, test methods, inspection rules, packaging, marking, transportation, and
storage of silicon-carbon.
This Standard applies to all kinds of silicon-carbon anode materials for lithium-ion
batteries.
2 Normative references
The following documents are indispensable for the application of this document. For
the dated references, only the editions with the dates indicated are applicable to this
document. For the undated references, the latest edition (including all the amendments)
are applicable to this document.
GB/T 191 Packaging - Pictorial marking for handling of goods
GB/T 2828.1 Sampling procedures for inspection by attributes - Part 1: Sampling
schemes indexed by acceptance quality limit (AQL) for lot-by-lot inspection
GB/T 2829 Sampling procedures and tables for periodic inspection by attributes
(apply to inspection of process stability)
GB/T 3782 Acetylene black
GB/T 4369 Lithium
GB/T 5187 Copper and copper alloy foil
GB/T 6388 Transport package shipping mark
GB/T 6682 Water for analytical laboratory use - Specification and test methods
GB/T 8170 Rules of rounding off for numerical values and expression and
judgement of limiting values
GB/T 13732 General rules for sampling inspection of bulk materials with uniform
size
GB/T 19077 Particle size analysis - Laser diffraction methods
GB/T 19587 Determination of the specific surface area of solids by gas adsorption
using the BET method
GB/T 21653 Nickel and Nickel-alloy Wire and Drawing Stock
GB/T 24533 Graphite negative electrode materials for lithium ion battery
GB/T 26125 Electrical and electronic products - Determination of six regulated
substances (lead, mercury, cadmium, hexavalent chromium, polybrominated
biphenyls, polybrominated diphenyl ethers)
GB/T 33827 Determination of magnetic impurities in anode nanomaterials for Li-
ion battery
3 Terms and definitions
The following term and definition applies to this document.
3.1
Silicon-carbon
Composite powder material composed of silicon material and carbon material. The
synergistic effect of silicon-carbon and cathode materials in a certain system can realize
multiple charging and discharging of lithium-ion batteries. During the charging process,
the silicon-carbon negative electrode accepts the intercalation of lithium ions. During
the discharging process, the lithium ions are extracted.
4 Classification and code
The products are classified according to their initial discharge specific capacity; mainly
divided into five categories:
- 400 mAh/g ≤ initial discharge specific capacity< 600 mAh/g; represented by SiC-I;
- 600 mAh/g ≤ initial discharge specific capacity< 900 mAh/g; represented by SiC-
Ⅱ;
- 900 mAh/g ≤ initial discharge specific capacity< 1200 mAh/g; represented by SiC-
Ⅲ;
- 1200 mAh/g ≤ initial discharge specific capacity< 1500 mAh/g; represented by SiC-
IV;
- Initial discharge specific capacity≥1500 mAh/g; represented by SiC-V.
7 Inspection rules
7.1 Sampling method
7.1.1 Sampling
Silicon-carbon is sampled according to GB/T 13732 “General rules for sampling
inspection of bulk materials with uniform size”. Insert a clean sampling drill (stainless
steel designation 316 or equivalent; diameter: no more than 30 mm) into the package
along the axis. The insertion depth must not be less than 4/5 of the package. Take
samples within 20 mm around the center axis of the material in the package. Sampling
is carried out in accordance with the relevant provisions on sampling in GB/T 2828.1
and GB/T 2829.
7.1.2 Sample label
After the sample is placed in the plastic sample jar, a label shall be attached to the outer
wall. The label shall include the following:
a) Sample category and number;
b) Overall material lot number and quantity;
c) Sample size;
d) Sampling date;
e) Name of sampler.
7.1.3 Storage of samples
The samples shall be sealed and stored in an environment protected from bag break,
rain and moisture. The effective storage period of spare samples is 12 months.
7.2 Inspection classification
7.2.1 Exit-factory inspection
Inspect the specific surface area, tap density, compaction density, silicon content,
magnetic impurities, trace metal elements, 0.1 C initial discharge specific capacity, 0.1
C initial coulombic efficiency, and regulated substance content of each lot. After
passing the inspection, stamp the quality inspection seal.
7.2.2 Type inspection
Inspect all technical requirements specified in this Standard. Type inspection is carried
out in one of the following situations:
a) When the model and supplier of raw materials are changed;
b) When there is a change in the production technology process;
c) When the production equipment has been shut down for more than half a year and
starts production again;
d) When customers have special requirements;
e) Under normal circumstances, the type inspection shall be conducted at least once
a year.
7.3 Acceptance rules
7.3.1 Products that meet the requirements of technical indicators in Table 1 are
conformity products. If there is 1 indicator that fails to meet the requirements of the
standard, double number of samples shall be taken from the sampling bag of the same
lot of products, to re-inspect the nonconformity item. If all the re-inspections are
conformity, it will be judged as conformity. If one item is nonconformity, it will be
judged as nonconformity.
7.3.2 The manufacturer shall ensure that, the products that leave the factory meet the
requirements of this Standard. When leaving the factory, each lot of products is
accompanied with an inspection report.
7.3.3 The re-inspection period of the receiving party is 2 months. If there is any
objection, it shall take double number of samples for re-inspection. If there is still a
dispute, it will be inspected by a qualified third-party testing agency.
8 Packaging, marking, storage, and transportation
8.1 Packaging
8.1.1 The packaging of the product shall comply with the provisions of GB/T 191. The
net weight shall be negotiated by both the supplier and the purchaser.
8.1.2 The packaging shall be carried out in a dry environment. The product shall be first
put into a waterproof packaging bag (PE sealing bag and aluminum-plastic sealing bag
are recommended). Special packaging requirements are negotiated by both the supplier
and the purchaser.
8.1.3 The packaged products are then packaged with outer packaging materials. The
packaging materials are negotiated by both the supplier and the purchaser.
8.2 Marking
The marking shall comply with the provisions of GB/T 6388. It shall generally include
Appendix A
(Normative)
Determination method of carbon content
A.1 Method summary
Combustion in an oxygen stream converts carbon to carbon monoxide and/or carbon
dioxide. Carbon monoxide is catalytically oxidized to carbon dioxide at high
temperatures. Use the infrared absorption spectrum of carbon dioxide in the oxygen
stream for the measurement.
A.2 Instruments and equipment
A.2.1 High-frequency infrared carbon-sulfur analyzer or carbon determinator. It
consists of an infrared source, an independent measuring cell, and a reference cell, etc.
A.2.2 Dryer.
A.2.3 Electronic balance: The sensitivity is 0.0001 g.
A.2.4 Porcelain crucible, according to the regulations of the instrument manufacturer,
can withstand combustion in a high-frequency induction furnace and does not produce
carbon chemicals. The blank value is less than 0.002%. The standard deviation is less
than 0.0005%.
Note: Carbon pollutants can usually be removed by burning the crucible in a muffle furnace in the
air. The burning time at 1000 ℃ is not less than 40 min. The burning time at 1350 ℃ is not
less than 15 min. Then take out the crucible; put it in a clean heat-resistant plate; cool it for 2
min~3 min; finally store the crucible in a dryer.
A.2.5 Crucible tongs, which can hold the porcelain crucible (see A.2.4).
A.3 Analytical procedure
WARNING - The main hazard associated with combustion analysis is the
combustion that occurs when the crucible is burned and during the resulting
molten state. Use crucible tongs at all times; store used crucibles in suitable
containers. Be careful when opening the oxygen valve. The oxygen during the
combustion process shall be purged from the instrument, because high
concentrations of oxygen can easily cause fires in small spaces.
A.3.1 Instrument state confirmation: Prepare for operation according to the
manufacturer's instructions; check the gas tightness of the combustion unit and the
measuring unit. Before calibrating the instrument and measuring the blank, use samples
that can measure carbon and sulfur content (add flux) to test at least 5 times. After the
instrument is stable, proceed to the next step.
A.3.2 Instrument calibration: Select certified standard samples to calibrate the
instrument according to the method specified in the instrument manual. For samples
with a wide range of carbon content distribution, a multi-point method or a linear
calibration instrument is recommended.
A.3.3 Weigh the sample: According to the carbon content of the sample, use an
electronic balance (see A.2.3) to accurately weigh a certain amount of sample; spread
it evenly in a ceramic crucible. And enter the sample name and mass (accurate to 0.0001
g) in the software.
Note: The weighing amount of the sample is related to the carbon content of the selected certified
reference material. The absolute carbon content of the sample shall be within the range of the
standard curve.
A.3.4 Add flux: Add 1.2 g~1.5 g of multi-component flux (tungsten, tin, iron) into the
crucible.
A.3.5 Use crucible tongs to place the crucible described in A.3.4 in the crucible holder.
After confirming that the input information is correct, start the test program.
A.3.6 After the test is completed, the crucible containing the sample is automatically
withdrawn from the furnace. Record the test result in the original record.
A.3.7 Hot crucible treatment: After the test is completed, use crucible tongs to put the
hot crucible into a uniform container to cool to prevent fire.
A.3.8 Shut down.
A.4 Result calculation and data processing
Read the data automatically displayed by the instrument; take the average of 2 parallel
tests. According to the "rounding off" provisions of GB/T 8170, retain 4 significant
figures, that is, ××.××%.
A.5 Test report
It shall contain the following content:
a) Sample name, lot number, test date, test instrument model, and operator, etc.;
b) Analysis results and presentation methods;
c) Abnormal phenomena observed in the determination;
Appendix B
(Normative)
Determination method of silicon content
B.1 Method summary
In the oxygen or air environment, the silicon-carbon material is fired at a high
temperature of 1200 °C. Carbon in it reacts with oxygen to generate CO2 gas, which is
discharged; silicon reacts with oxygen to generate SiO2. Finally all the material is
converted into SiO2. According to the mass of the reaction product SiO2, the mass of
the silicon element in the original sample can be calculated, to obtain the content of the
silicon element in the silicon-carbon material.
B.2 Instruments and equipment
B.2.1 Box-type resistance furnace or atmosphere furnace: It can be used for a long time
at a temperature of not less than 1200 °C.
B.2.2 Corundum crucible: It can be used for a long time at a temperature of not less
than 1200 °C.
B.2.3 Electronic balance: The sensitivity is 0.0001 g.
B.2.4 Medicine spoon.
B.2.5 Crucible tongs.
B.2.6 Blast oven.
B.2.7 Dryer.
B.2.8 Stainless steel tray.
B.3 Analytical procedure
B.3.1 Crucible pretreatment
Before the test, clean and dry the corundum crucible; burn it in a box-type resistance
furnace or atmosphere furnace (see B.2.1) at 1200 °C for 1 h. When the temperature
drops below 200 ℃, take it out. After a little cooling, put it into a dryer to cool down to
room temperature, and weigh. Then burn again, until the mass difference between the
two times is not more than 0.3 mg.
B.3.2 Sample weighing
Weigh 1.0000 g~1.2000 g of the sample into the corundum crucible, accurate to 0.1 mg.
Weigh 2 pieces and carry out a parallel test.
B.3.3 Test
B.3.3.1 Put the corundum crucibles with the weighed samples into the box-type
resistance furnace or atmosphere furnace (see B.2.1) in turn. The corundum crucibles
shall not be in contact with each other.
B.3.3.2 Burning program setting of box-type resistance furnace or atmosphere furnace
(see B.2.1): The heating rate is not more than 20 ℃/min. Rise from room temperature
to 1200 ℃; burn at 1200 ℃ for 8 h; then stop heating.
According to the requirements of the equipment manual or other technical documents,
pre-dry the box-type resistance furnace or atmosphere furnace, to prevent the failure of
instruments and crucibles such as rupture. During the heating process, if the sample or
crucible bursts, splashes or becomes contaminated, the heating program can be
readjusted; and the test can be redone.
B.3.3.3 Start the heating program and start burning.
B.3.3.4 Cool and weigh: When the temperature of the box-type resistance furnace or
atmosphere furnace (see B.2.1) drops below 200 °C, open the furnace door; use crucible
tongs to take out the crucible; place it in a clean stainless steel tray. Cool for 2 min;
place the tray and the sample into a dryer; cool to room temperature. Use an electronic
balance (see B.2.3) to weigh the total mass of the cooled crucible and product.
B.3.3.5 Constant weight: Put the crucible and product into the box-type resistance
furnace or atmosphere furnace (see B.2.1) again. According to the steps of
B.3.3.1~B.3.3.4, burn and weigh again. Compare and obtain the mass difference with
the first burning. If it does not exceed 0.3 mg, the test is over. Otherwise, repeat this
step until the mass difference after two burnings does not exceed 0.3 mg.
B.3.4 Result calculation
B.3.4.1 According to the steps of B.3.3, respectively record the crucible mass m0, the
sample mass m1, the total mass m2 of crucible and product after burning, and the total
mass m3 of crucible and product after the constant weight. Then the silicon content in
the sample is calculated according to formula (B.1):
Where:
wSi - The mass fraction of silicon in the sample;
D.4.1 Put the specimen and conductive agent into the oven; bake at 120 ℃ for 4 h; then
transfer to a drying vessel to cool. Weigh the mixture powder (accurate to 0.0001 g) of
4.55 g of specimen and 0.15 g of conductive agent INTO a small beaker with a capacity
of 50 mL; then add 6.0 g of 5% PAA aqueous solution to the beaker. Finally, use a
planetary stirrer to prepare a paste (stirring time 15 min; stirring speed 2000 r/min).
Note: The reference specimen, the binder, and the conductive agent are weighed in a mass ratio of
91 : 6 : 3.
D.4.2 Apply the paste in D.4.1 evenly on the copper foil; use a 200 μm film coater to
scrape the paste on the copper foil, until the surface is smooth. Then put it into a blast
drying oven and bake it at 100 °C for 2 h. Or use an equivalent type of coating method
to obtain a pole piece with a single surface density of 60 g/m2~100 g/m2.
D.4.3 The baked pole pieces are cut and pressed into electrodes of various shapes
(rectangular strips, strips or circles, etc.). After accurate weighing (accurate to 0.00001
g), put it into a vacuum drying oven; bake it at 120 °C for 8 h under vacuum conditions,
to prepare the silicon-carbon working electrode.
D.4.4 In an argon atmosphere glove box, cut metal lithium into rectangular strips, strips
or circles, etc. Then, press the above-mentioned cut metal lithium to the end of the cut
strip-shaped nickel mesh (or other current collectors with the same performance), to
form a counter electrode (or directly use metal lithium as the counter electrode).
D.4.5 ASSEMBLE the positive electrode material electrode and the counter electrode
made by the above steps, AND 1 mol/L LiPF6 EC (ethylene carbonate)/DMC (dimethyl
carbonate)/EMC (ethyl methyl carbonate) (the volume ratio of EC to DMC to EMD is
1 : 1 : 1) electrolyte (or other electrolytes with equivalent performance), in a glove box
to form a well-sealed half-cell conforming to the electrode system.
Note: The specimen pole piece is prepared in a dry room. The temperature is 23 ℃±2 ℃. The
relative humidity is ≤35%. The sample cell is prepared in a glove box. The temperature is
23 ℃±2 ℃. The moisture content is less than or equal to 1 mg/m3. The oxygen content is
less than or equal to 1 mg/m3.
D.5 Analytical procedure
Conduct charge-discharge cycle of button cell on cell program-controlled tester.
Calculate the average of the data of 4 button cells. The test conditions of the initial
discharge specific capacity and the initial coulombic efficiency are as follows: The
charge-discharge rate is 0.1 C; the voltage range is 0.005 V~1.5 V.
D.6 Result calculation and data processing
D.6.1 The initial discharge specific capacity and initial coulombic efficiency of the
specimen are calculated according to formula (D.1), formula (D.2), and formula (D.3).
...