Laboratory lithium ion battery powder resistivity MSA and compaction density MSA

Powder resistance:

The rate performance of lithium ion battery is closely related to the battery resistance. Battery resistance includes ion resistance and electronic resistance. Ion resistance mainly refers to the resistance of lithium ion in the electrolyte in the electrode hole, the resistance of lithium ion passing through the SEI film, and the resistance of lithium ion and electron. The charge transfer resistance at the interface of the active material/SEI film and the solid diffusion resistance of lithium ion in the active material. Electronic resistance mainly refers to the resistance of positive and negative active materials, collector resistance, contact resistance between active materials and contact resistance between active materials and collector. And the welding resistance of the joint. In the actual battery development and production process, the ion resistance part needs to be evaluated at the end of the finished battery, and the electronic resistance part can be quickly evaluated at the end of the material and the pole shoe. Therefore, accurate evaluation of the electronic resistance of materials and electrodes is very important for batteries. Resistance estimation is of great significance.

Measurement system analysis
Test conditions: 5 samples, 3 operators, 3 times/operator

%GRR accepted rule	%GRR<10%	Excellent
	10%<%GRR〈30%	Acceptable
	%GRR>30%	Unacceptable
ndc accepted rule	ndc>10	Excellent
	5<ndc < 1	Acceptable
	ndc < 5	Unacceptable

♦ Compact density : GRR-Excellent
♦ Powder Resistance : GRR-Excellent

Applications

Case
1. LCO material evaluation (evaluation of the electrical property of modified powder (LCO))

Parameter: 10-200MPa, 5MPa step, hold for 15s
Results: When the density of the modified powder was more than 3.87g/cm3 (applied pressure>75MPa), the conductivity of the modified powder was significantly improved.
The effectiveness of the modification can be evaluated.

2.NCM material assessment (relation of powder resistivity and electrode: NCM material)

Result analysis

By adjusting the nickel content in the ternary material, the powder conductivity increases with the increase of nickel content.
Compared with three ternary electrodes with different nickel content, the conductivity of the electrode increases with the increase of nickel content;
Powder resistivity and electrode have the same trend!

3.NCMA material assessment (relation of powder resistivity and electrode: NCMA material)

Result analysis

The conductivity trend of quaternary powder and electrode under three different modified conditions is NCMAT>NCMA-2>NCMA-3;
The conductivity of NCMA43 in powder state is much smaller than that of the first two samples, but the difference in the electrode plate is very small, which may be related to the addition of conductivity in the electrode plate, which reduces the difference between powders.
Powder resistivity and electrode have the same trend!

4.LFP material assessment (relation of powder resistivity and electrode: LFP material)

Result analysis

Compared with LFP powder and electrode sheet under four different modified conditions, the conductivity trend of LFP powder and electrode sheet is as follows
LFP-1＞LFP-2＞LFP-3＞LFP-4
Powder resistivity and electrode have the same trend!

5.Graphite material assessment (compact density: parallel test 5 times)

Parameter: 20~200MPa, 20MPa steps, keep 30s, relief 3MPa steps, keep 10s

Result analysis

The cov of five parallel samples is less than 0.1% in the whole pressure range, which indicates that the equipment has good repeatability.
With the increase of pressure, the density of graphite material gradually increases and tends to be flat.
Under pressure and pressure release, the rebound of powder thickness reaches the maximum value at 80MPa, which indicates that this condition is the maximum pressure that the powder can bear. If it is too large, the material structure is likely to be damaged.

6.Carbon material assessment (compact density VS resistivity: parallel test 5 times)

Parameter: release mode: 10~200MPa, 10MPa step length, 10s result: the cov of five parallel samples in the whole pressure range is less than 0.3%, indicating that the equipment has good repeatability.

With the increase of pressure, the compaction density of carbon materials gradually increases, and the compaction range is 0.5-0.9g/cm3.

♦ Part of the data comes from partners, and the copyright belongs to interested parties. No reproduction or use without consent
High precision pressure system: driven by servo motor.
High-precision displacement sensor: accurately measure thickness change.
Special fixture for powder sample resistivity and compaction density test: simplify the powder loading and cleaning process.
Multi-function: One-stop data acquisition of key parameters such as pressure, resistance, thickness, temperature and humidity with high reliability, providing complete traceability for each result.
Automatic measurement: flexible measurement modes are provided for different types of samples. All process parameter settings are integrated into a simple software control interface, and measurement can be started with only one button.

PRCDMS software:

1. The pressure can be set arbitrarily within the maximum pressure range.
2. Resistivity under different pressures can be continuously measured, and the rate and interval of pressure scanning can be controlled.
3. Different data analysis curves can be generated, including resistivity-pressure curve, resistivity-thickness curve, compaction density-pressure curve and pressure-thickness curve.
4. Two resistance data acquisition modes: interval time mode or automatic steady-state condition determination mode.
5. Data statistics and analysis function.
6. Automatically generate reports using resistivity (or conductivity) and compaction density values.
Integrated design: control and measurement of integrated pressure, resistivity and thickness control and measurement system.

Application fields
Carbon powder:
Active materials for lithium-ion batteries and various electronic components (capacitors and resistors, etc.), including graphite, activated carbon, coke, carbon black, carbon fiber; Carbon nanoparticles, etc.

Metal oxide or metal composite powder:
Lithium ion battery active materials, conductive paste, conductive coating and other functional films, including LCO, LMO, LFR NCM, LTO copper powder; ITO powder; etc.

Parameter
Resistance range	1uΩ-1200mΩ
Resistance accuracy	±0.05%
Resistivity range	10^(-6)Ω cm-10^9Ω cm
Conductivity range	10^(-9)^S/cm-10^6 S/cm
Pressure range	0-200 MPa
Pressure accuracy	±0.30%F.S
Thickness range	0-8 mm
Thickness accuracy/resolution	0.5um/±5um
Max filling capacity	Φ16*8 mm
Temperature and humidity range	20-90%RH, 0-50℃
Temperature and humidity accuracy	±5%RH, ±2℃

Installation requirement
Voltage	220V
Voltage change tolerance	±10%
Power consumption	2100W
Environment temperature	25±5℃
Environmental humidity	Humidity at 40℃ ＜80%RH
Environmental magnetic field	Away from intense electromagnetic fields
Net weight	165kg
Dimension(W*D*H)	370*580*1100 mm