In-Situ Cell Swelling Analyzer for Battery Research

MSE Supplies offers In-Situ Cell Swelling Analyzer. It is a testing system equipped with high precision thickness measuring sensor and mechanical sensor, which can achieve long-term stability and accurate detection of cell thickness and swelling force to realize performance evaluation under different conditions. The in-situ analysis method can be used by lithium battery researchers to analyze the cells' swelling behavior and the whole production processes, which allows researchers to design cells with better performance.

Lithium-ion Batteries Swelling Behavior and its Importance in Battery Research

During the lithium-ion batteries charging and discharging process, lithium ions are inserted and extracted in the negative electrode, which causes cells to expand and contract. The ideal process is that the insertion and extraction of lithium ions is reversible; however, it is generally not how it works in the actual process. Part of the lithium ions cannot be extracted from the negative electrode or deposited on the surface of the anode, which results in irreversible swelling of the battery cell, deformation of the battery cell, fragmentation of material particles, rupture of the SEI film, and the consumption of electrolyte.

The swelling behavior of the battery is an important indicator in evaluating the reliability of the battery. During the production process, the negative electrode material's particle size, binder and pole piece structure must be optimized. The theoretical swelling ratio of next generation high-energy density anode materials (silicon, lithium metal, etc.) is much greater than graphite anode materials. Therefore, we can optimize the battery cell module to ensure safety and to improve module space utilization by using the result of battery cell swelling behavior. Additionally, our system can also accurately determine the battery cell's lithium SOC window under different magnifications, which can be helpful in developing fast charging technology.

Features:

• Multi-function test modes: Constant pressure and constant gap test modes can be realized for the cell, and the performance of the cell under different stress conditions can be evaluated
• High precision control:  Accurately control the gap change within ~1 um by active modulation, and get the accurate swelling force change of the cell
  during the test
• Highly stable and reliable
• Ability to realize performance evaluation under different conditions

Applications:

• Lithium Plating Analysis
• Material Evaluation: Anode Material, Binder
• Process Conditions: Pressure, Temperature, Stress
• Cell Structure: M6S V.S SLS
• Others

Model Types:

Technical Specifications：

* Please contact us for multi-channel option.

Examples: 

1 .Swelling behavior analysis of different anode materials

Above are two types of anode material batteries with the same design and capacity. The full charge swelling and irreversible swelling thicknesses of B are greater than A, which can be used to screen and evaluate battery anode materials swelling requirements.
The swelling differences of three different anode material cells can be used to study the in-situ swelling process mechanism of anode materials during charging and discharging process.

2. Swelling behavior analysis of different binder

From above picture, we can see that the level of irreversible swelling of four different binder material batteries is almost the same. The main difference is the single cycle full charge swelling thickness, and Binder C has the best swelling suppression effect. These information can be used to evaluate different binder materials.

3. Non-destructive Lithium plating window judgment

Compared with normal Li-insertion curve, the Li plating swelling curve reaches inflection point when reaching Li plating voltage. Accordingly, accurate Li plating rate, voltage, and SOC window will be acquired.

4. Step charge

Quantitative lithium analysis voltage and SOC window of a certain lithium analysis rate can effectively guide the cascade fast charging technology, and realize safe fast charging through the charging scheme.

5. Cell structure

Above are two models used to evaluate the swelling of different anode cells. The two sides of the winding are bound and the crimping stress caused by the lateral swelling accumulates in the middle, which causes the thickness to increase. The four sides of the lamination are not bound and the crimping stress of the group A pole piece with larger lateral swelling is released, which leads to thickness decreases. We can conclude that our In-Situ Cell Swelling Analyzer can be used to analyze the influence of process on stress and strain.

6. Different pressure conditions

By increasing the pressure properly, the irreversible swelling ratio of the battery can be reduced. During the charging process, the two inflection points of the swelling curve
correspond to the two peaks of the differential capacity curve indicates the swelling of the battery is related to the phase transition of deintercalation of lithium.

7. Different temperature conditions

When the temperature rises from room temperature 25°C to 45°C and 60°C, and drops from 25°C to 0°C, the cell's irreversible swelling increases. However, the causes of irreversible swelling might be different under high temperature and low temperature conditions.

8. Different stress conditions

With the increase of the stress, the swelling stress of the cell increases gradually, which leads to the increase of the polarization of the cell and the deterioration of the dynamic performance. Therefore, we can conclude that the initial stress has influences on the design of the cell packing.

9. Thickness and stress changing during charge-discharge

By using our In-Situ Cell Swelling Analyzer, we can monitor the changes of swelling thickness and swelling force of flexible cell under constant pressure and constant gap mode. We can see that the curves of swelling thickness and swelling force were related to the structural phase transition during the charging and discharging process. This in-situ analysis method can be used to analyze the swelling behavior of cells with different systems and production processes, which are helpful in designing cells with better performance.