Battery Powder Resistivity & Compaction Density Measurement System

MSE Supplies offers a Battery Powder Resistivity & Compaction Density Measurement System. The pressure can reach up to 200MPa and the resistivity measurement can reach up to 1200MΩ. This system is mainly used to measure the powder resistivity,  compaction density, essential elements closely related to the rate performance of lithium-ion batteries.

The battery resistance can be divided into ionic resistance (resistance of lithium ions in the electrolyte in electro pores, resistance of through solid electrolyte interface (SEI) membrane, etc.) and electronic resistance (resistance of positive and negative active materials, current collector resistance, etc.). Our system can be used to measure the ionic resistance parts evaluated at the finished battery end and electronic resistance evaluation during the material and pole piece end. These can significantly increase the quality of the battery and make the adjustments of the production in time.

Importance of Powder Resistance

The rate performance of lithium-ion batteries is closely related to the battery resistance. The battery resistance includes ionic resistance and electronic resistance. The ionic resistance mainly refers to the resistance of lithium ions in the electrolyte in the electrode pores, the resistance of lithium ions through the SEI membrane, and the resistance of lithium ions and electrons. The charge transfer resistance of the active material/SEI film interface and the solid phase diffusion resistance of lithium ions inside the active material. The electronic resistance mainly refers to the resistance of the positive and negative active materials, the current collector resistance, the contact resistance between the active materials, and the contact resistance between the active material and the current collector and the welding resistance of tabs. In the actual battery development and production process, the ionic resistance part needs to be evaluated at the finished battery end, and the electronic resistance part can be quickly evaluated at the material and pole piece end. Therefore, the accurate evaluation of the material and the electrode electronic resistance is important for the battery. The resistance estimation is of great significance.

Applications:

• Lithium Iron Phosphate (LFP) Material Assessment
• Carbon Material Assessment
• Graphite Material Assessment
• Lithium Cobalt Oxide (LCO) Material Assessment
• Material Assessment
• Others

Technical Specifications：

 Difference between different models:

Examples:

1. LCO Material Assessment: Evaluation of electrical properties of modified powder 

Parameter: 10~200MPa, 5MPa steps (15s)
Results: When the Compact density of the modified powder is greater than 3.87g/cm³ (applied pressure > 75MPa), the conductivity of the modified powder is greatly improved.
We can evaluate the effectiveness of the modification.

2. NCM Material Assessment: Relation of powder resistivity and electrode

From above graphs, we can see that by adjusting the Ni content in the ternary material, the powder conductivity increases as Ni content increases. Compared with three kinds of ternary electrodes with different Ni content, the conductivity of the electrode increases with the increasing of Ni content. We can concludes that powder resistivity and electrode have the same behavior.

3. NCMA Material Assessment: Relation of powder resistivity and electrode

The conductivity trend of the quaternary powder and electrode under three different modification conditions is NCMA-1 > NCMA-2 > NCMA-3. The conductivity of NCMA-3 in powder state is much smaller than the former two samples, but there is a small difference in the electrode plate, which may be related to the addition of conductive in the electrode plate, which reduces the differences between the powder.

4. LFP Material Assessment: Relation of powder resistivity and electrode

The above graphs show the conductivity trend of LFP powder and electrode sheet as follows: LFP-1 > LFP-2 > LFP-3 > LFP-4.

5. Graphite Material Assessment: Compact density

The above graphs show the equipment has good repeatability. With the increase of pressure, the compact density of graphite material increases gradually and tends to be flat. The rebound of powder thickness under pressure and pressure relief reaches the maximum value at 80MPa, which indicates the maximum pressure that the powder can bear. If exceeds the threshold, the material structure is likely to be damaged.

6. Carbon Material Assessment: Compact density VS Resistivity

Parameter: relief mode: 10~200MPa, 10MPa steps (10s)
The above graph shows that the equipment has good repeatability. With the increase of pressure, the compact density of carbon material increases gradually, and the compaction range is between 0.5~0.9 g/cm³.