Battery Cell Winding with Enveloped Diaphragm Compounding
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Solution Overview
Problem
The existing winding process for lithium battery cell manufacturing results in poor compounding between the diaphragm and pole pieces, leading to suboptimal cell quality due to direct contact of the diaphragm with the compounding device, causing adhesive issues and affecting the alignment and bonding of the diaphragm with the cathode and anode pole pieces.
Innovation Solution
A cell forming apparatus and process that includes a compounding device with upper and lower pressure rollers to compound the cathode and anode pole pieces with the diaphragm, ensuring the diaphragm is enveloped between them, preventing direct contact with the rollers and enhancing the bonding effect, along with a pole piece processing apparatus to create a broken portion on the cathode pole piece for improved structural integrity and reduced lithium precipitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the diaphragm is directly compounded with the pole pieces using conventional winding process, then the manufacturing process is simple, but the compounding effect between diaphragm and pole pieces is poor
Solution Approach 1:
The patent introduces a specially designed compounding device that acts as an intermediary between the diaphragm and pole pieces. This device includes pressure rollers and heating elements that mediate the compounding process, ensuring proper adhesion without direct harmful contact between the diaphragm adhesive and conventional winding equipment.
Solution Approach 2:
The compounding device changes physical parameters (temperature, pressure) during the compounding process. By controlling temperature and pressure parameters, the device enhances the adhesive bonding between diaphragm and pole pieces, transforming the compounding effect from poor to high quality.
2Reliability
If the diaphragm directly contacts the compounding device, then the compounding process is straightforward, but adhesive issues occur affecting diaphragm bonding quality
Solution Approach 1:
The compounding device serves as a controlled intermediary that prevents direct harmful contact between the diaphragm adhesive and conventional winding equipment. The device's design ensures that adhesion occurs under controlled conditions without contamination.
Solution Approach 2:
The compounding device creates a controlled environment that protects the adhesive interface from contamination. By controlling the compounding environment, the device prevents harmful factors from affecting the bonding reliability between diaphragm and pole pieces.
3Reliability
If the cell is wound without broken portions on pole pieces, then the manufacturing process is simple, but lithium precipitation occurs during battery operation
Solution Approach 1:
The patent applies segmentation by creating broken portions on the pole pieces during the compounding process. This divides the continuous pole piece structure into segmented sections, which prevents lithium precipitation by ensuring balanced lithium intercalation across different cell regions.
Solution Approach 2:
The broken portions are created in advance during the compounding process, before the cell is wound and before battery operation begins. This preliminary action prevents lithium precipitation issues that would otherwise occur during battery cycling.
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
The solution improves the compounding effect between the diaphragm and pole pieces, enhancing the quality of the manufactured cell by preventing adhesive issues and maintaining structural integrity, which reduces lithium precipitation and maintains balanced lithium intercalation sites, thus improving the overall performance and reliability of the lithium battery.
Implementation Method 1
the compounding device comprises an upper pressure roller and a lower pressure roller, and wherein the cathode pole piece, the anode pole piece, and the first diaphragm are capable of passing between the upper pressure roller and the lower pressure roller
Implementation Method 2
both the upper pressure roller and the lower pressure roller are heat pressure rollers
Data Source
AI summary
The present disclosure provides a cell forming apparatus and a cell forming process. Prior to entering a winding device, a device compounds the anode pole piece and the cathode pole piece with a first diaphragm to obtain a first compound material strip. Since the pole pieces are respectively located on two sides of the first diaphragm, the first diaphragm is enveloped between the anode pole piece and the cathode pole piece. During the compounding process, the surfaces on both sides of the first diaphragm will not come into direct contact with the compounding device. Therefore, the adhesive on the surface of the first diaphragm does not adhere to the compounding device, thereby improving the compounding effect of the first diaphragm with the anode pole piece and the cathode pole piece, and thus enhancing the quality of the manufactured cell. In addition, the present disclosure also provides a cell.