Electrode Assembly Bending Region Inactivation Against Lithium Plating
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Solution Overview
Problem
Existing electrode assemblies in battery cells are prone to lithium precipitation during charging, leading to poor safety performance, and there is a lack of suitable winding devices for industrialized production of improved electrode assemblies.
Innovation Solution
An electrode assembly with an inactive region on the positive electrode plate's bending region, where the inactive region reduces the effective active area of the positive electrode active substance layer, increasing the CB value and preventing lithium precipitation, combined with a winding device that inactivates the positive electrode active substance layer using an inactivating agent to form the inactive region during the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the positive electrode active substance layer is fully active in the bending region, then the battery capacity is maximized, but lithium precipitation occurs during charging leading to poor safety performance
Solution Approach 1:
The patent applies local quality by creating an inactive region with different properties (no active substance) in the bending region of the positive electrode plate, while the non-bending regions maintain full active substance coverage. This localized differentiation resolves the contradiction by preventing lithium precipitation specifically where bending occurs, without reducing capacity in the safe regions.
2Reliability
If an inactive region is created in the bending region to prevent lithium precipitation, then safety performance is improved, but the effective active area of the positive electrode is reduced
Solution Approach 1:
The patent applies preliminary action by forming the inactive region during the electrode plate manufacturing process before winding, using a mask to prevent active substance deposition in the bending region. This approach integrates the safety feature into the base manufacturing flow without requiring post-processing steps, thereby maintaining manufacturing efficiency while ensuring safety.
3Reliability
If the electrode assembly structure is improved to enhance safety performance, then lithium precipitation is prevented, but no corresponding winding device is available for industrialized production
Solution Approach 1:
The patent applies preliminary action by designing the mask to define the inactive region pattern before electrode plate manufacturing begins. The mask is positioned on the electrode plate precursor, and the active substance is deposited only in regions where it should be active. This pre-planning approach enables standard winding devices to produce safe electrode assemblies without requiring complex post-manufacturing modifications.
Solution Approach 2:
The patent introduces a mask as an intermediary tool that mediates between the manufacturing process and the final electrode structure. The mask temporarily occupies space during manufacturing to prevent active substance deposition in bending regions, then is removed. This intermediary enables precise control of the inactive region formation using existing manufacturing equipment, bridging the gap between improved safety design and industrialized production capability.
Data Source
AI summary
This application relates to an electrode assembly, and a winding device and manufacturing method thereof, a battery cell, a battery, and an electric apparatus, and pertains to the field of battery manufacturing technologies. This application proposes an electrode assembly including a positive electrode plate, where a bending region is formed after the positive electrode plate is wound; and the positive electrode plate includes a positive electrode current collector and a positive electrode active substance layer disposed on a surface of the positive electrode current collector, where the positive electrode active substance layer includes an inactive region, and at least part of the inactive region is located in the bending region. This application further proposes a winding device and a manufacturing method of electrode assembly, so as to shape the electrode assembly. This application further proposes a battery cell, a battery, and an electric apparatus that include the electrode assembly.