Nonaqueous Battery Electrode Plate Uniform Thickness Control
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Solution Overview
Problem
Existing methods for manufacturing nonaqueous secondary battery electrode plates, such as the roll and application methods, face challenges in achieving uniform thickness and preventing internal short circuits due to nonuniform active material layers, which can lead to reduced charge/discharge capacity and safety issues.
Innovation Solution
The electrode plates are formed with a composite material layer on a current collector plate, where the slope in the thickness direction of the end surfaces is controlled between 0 and 1, using a kneading and dispersion process with a nonaqueous dispersion medium, ensuring a uniform thickness and preventing gaps or protrusions that could cause internal short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the roll method is used to form the active material layer, then the thickness can be controlled, but the active material layer becomes nonuniform and breaks occur due to pressure bonding in wet state
Solution Approach 1:
The patent applies a preliminary drying step before pressure bonding to remove the solvent from the active material layer. This preliminary action prevents the layer from being in a wet state during bonding, eliminating the cause of breaks and nonuniformity that occurs in conventional roll methods.
Solution Approach 2:
The patent extracts the drying step as a separate preliminary process before the main pressure bonding operation. By removing the solvent beforehand, the process avoids the harmful effects of bonding wet material, thus taking out the problematic condition from the manufacturing sequence.
2Ease of manufacture
If the application method is used to form the active material layer, then the manufacturing process is simplified, but the layer becomes nonuniform with slopes and protrusions causing internal short circuits
Solution Approach 1:
The patent introduces a preliminary drying step after application to eliminate surface tension effects and solvent-induced deformation before the material sets. This preliminary action prevents the formation of slopes and protrusions that would otherwise occur during the application process.
Solution Approach 2:
The patent changes the physical state of the applied material by controlling the drying process parameters (temperature, time, atmosphere). This parameter control transforms the material from a solvent-containing state prone to deformation to a stable, uniform solid layer.
3Manufacturing precision
If masking tape is applied to prevent nonuniformity at end portions, then the thickness uniformity improves, but the process complexity increases and plain portions are reduced
Solution Approach 1:
The patent removes the masking tape step entirely by extracting the root cause problem (solvent presence during bonding) and addressing it through preliminary drying. This eliminates the need for auxiliary masking components and the associated process complexity.
Solution Approach 2:
Instead of using masking tape as an intermediary to protect certain areas, the patent uses controlled drying as a mediating process that uniformly prepares the entire active material layer, eliminating the need for selective masking and subsequent tape removal steps.
4Quantity of substance
If the active material layer is made thicker to increase capacity, then the charge/discharge capacity increases, but the nonuniformity and risk of internal short circuits increase
Solution Approach 1:
The patent applies preliminary drying to thicker active material layers to ensure complete solvent removal before any potential bonding or handling. This preliminary action prevents the formation of nonuniformities and internal stresses that would be more pronounced in thicker layers, thereby maintaining safety and reliability.
Solution Approach 2:
The patent optimizes drying parameters (temperature, time, air flow) to ensure uniform solvent removal throughout thicker active material layers. By controlling these parameters, the process achieves uniform thickness and eliminates the nonuniformities that would otherwise lead to internal short circuits in high-capacity electrodes.
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 results in electrode plates with a uniform thickness and increased capacity, enhancing the safety and performance of nonaqueous secondary batteries by ensuring consistent active material distribution and preventing internal short circuits.
Implementation Method 1
the heating rolls 100a to 100d heat the positive electrode composite material 101 to reduce the water content therein
Implementation Method 2
a surface tension occurs on a composite coating material, so that an end portion 1a of a composite material layer 1 slopes gently
Data Source
Figure 1~2
Figure 3~4
Figure 5~7
AI summary
To provide an electrode plate capable of retaining a larger amount of active material and having a composite material layer uniform in thickness, a positive electrode plate (6) or a negative electrode plate (7) is formed by laminating a composite material layer (1) of the active material on a surface of a current collector plate (2) in strip form. A slope in a thickness direction (X/Z) of the end surfaces of the composite material layer (1) along the longer sides of the current collector plate (2) is "0 < (X/Z) ≤ 1".