Pouch Cell Activation Protocol Using Thickness Feedback
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Solution Overview
Problem
The existing activation process for pouch-type secondary batteries is hindered by a lengthy lead time for the additional charge/discharge operation, which delays the entire activation process and reduces productivity.
Innovation Solution
A method for generating a charge/discharge protocol that involves measuring the secondary battery thickness increase rate over time while repeating charging/discharging between specific voltage ranges, allowing for the determination of an optimal voltage range for forming pores in the electrode active material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the additional charge/discharge operation is performed with a wide voltage range to ensure sufficient pore formation in the electrode active material, then the activation completeness is improved, but the lead time of the operation increases
Solution Approach 1:
The patent applies parameter changes by systematically varying the charge/discharge voltage range parameters to identify the optimal activation protocol. Multiple voltage ranges are tested (e.g., 2.8V-4.35V, 3.0V-4.35V, 3.2V-4.35V) to determine which parameters yield sufficient pore formation in the shortest time, directly resolving the contradiction between activation completeness and lead time.
2Reliability
If the additional charge/discharge operation is performed repeatedly to ensure sufficient pore formation, then the activation completeness is improved, but the productivity decreases
Solution Approach 1:
The patent applies partial action by determining the minimum necessary number of charge/discharge repetitions (e.g., 5 times) required to achieve sufficient pore formation. This avoids excessive repetitions that would reduce productivity while ensuring activation completeness is met through the optimized protocol derived from thickness increase rate measurements.
3Productivity
If the charge/discharge voltage range is optimized to shorten the lead time, then the productivity is improved, but the pore formation completeness may be insufficient
Solution Approach 1:
The patent applies feedback by using the secondary battery thickness increase rate as a measurement indicator to evaluate pore formation progress. This feedback mechanism allows the optimization of charge/discharge protocols (voltage range, number of repetitions) to achieve the best balance between productivity and pore formation completeness, ensuring that shortened lead times do not compromise activation quality.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach shortens the lead time of the additional charge/discharge operation and the entire activation process, enhancing productivity and ensuring sufficient pore formation in the electrode active material.
Implementation Method 1
charging/discharging is performed under conditions necessary for activation. Due to characteristics of a cell, this activation process must be preceded during a first cycle in order to activate a positive electrode active material and generate a solid electrolyte interface (SEI) on a negative electrode
Implementation Method 2
measuring a secondary battery thickness increase rate over time while repeating charging/discharging between a first voltage and a second voltage higher than the first voltage
Data Source
AI summary
A method of generating a charge/discharge protocol of an additional charging/discharging operation included in an activation method with respect to assembled secondary batteries is provided. The method includes operation (a) of measuring a secondary battery thickness increase rate over time while repeating charging/discharging between a first voltage and a second voltage higher than the first voltage with respect to a first secondary battery; operation (b) of performing, at least once, an operation of performing operation (a) with respect to a second secondary battery after fixing the second voltage and changing the first voltage; operation (c) of determining one of first voltages except for a first voltage at a lowest rate from among measured secondary battery thickness increase rates as a lower limit voltage; and operation (d) of setting a protocol so that charging/discharging is repeated between the lower limit voltage and the second voltage.