Battery Laminate Adhesive Patterning to Prevent Separator Curling
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Solution Overview
Problem
Conventional methods for producing secondary battery laminates result in separator peeling and curling during cutting, which compromises the integrity and safety of the battery structure.
Innovation Solution
A specific distribution of adhesive material is applied on the affixing surfaces of the negative electrode and separator, with higher coating weights in non-projected sections to inhibit separator peeling and curling, and the adhesive is strategically avoided at edge regions to prevent attachment to cutting tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a stacked structure of multiple battery cells is used to increase capacity, then the battery capacity increases, but the internal stress during charging and discharging increases causing adhesion failure and reduced reliability
Solution Approach 1:
The battery cell is divided into multiple stacked battery packs, each containing a smaller number of battery cells (e.g., 3-5 cells per pack). This segmentation reduces the internal stress within each individual pack during charging and discharging, preventing adhesion failure between the current collector and electrode, while still achieving high overall capacity through the stacking of multiple packs in series or parallel configurations.
2Device complexity
If the battery cell size is increased to reduce the number of cells, then the device complexity decreases, but the manufacturing precision requirements increase due to larger internal stress
Solution Approach 1:
Instead of using a small number of large battery cells, the invention segments the battery into multiple smaller cells arranged in stacks. Each stack contains a manageable number of cells (3-5), which reduces the internal stress and deformation in each individual cell during operation. This segmentation allows for more relaxed manufacturing precision requirements while maintaining overall battery performance and reducing device complexity.
3Ease of manufacture
If conventional battery structures are used, then the manufacturing process is simple, but the battery expands during charging and discharging causing adhesion failure and reduced reliability
Solution Approach 1:
The battery is constructed with multiple stacks, where each stack contains a limited number of battery cells (3-5 cells) connected in series. This segmented architecture reduces the cumulative expansion and internal stress in each stack during charging and discharging cycles, preventing adhesion failure between the current collector and electrode. The manufacturing process remains relatively simple as it uses conventional battery cell production methods, but the stacked configuration significantly improves reliability.
4Quantity of substance
If a large number of battery cells are connected in parallel to increase capacity, then the battery capacity increases, but the battery expands and contracts during charging and discharging causing adhesion failure
Solution Approach 1:
Instead of connecting a large number of battery cells in parallel, the invention segments the battery into multiple stacks with a smaller number of cells in each stack (3-5 cells per stack). This segmentation reduces the expansion and contraction stress in each individual stack during charging and discharging, maintaining structural stability and preventing adhesion failure. The overall battery capacity is achieved by stacking multiple such units in series or parallel configurations.
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
Provided is a laminate for a secondary battery in which separator curling up is inhibited. A method of producing a laminate for a secondary battery includes: a step (A) of producing an affixed body including a negative electrode material and separator webs affixed to both surfaces of the negative electrode material or an affixed body including a negative electrode material, a first separator web, a positive electrode, and a second separator web affixed in stated order; and a step (B) of cutting the affixed body. The step (A) includes a step (a1) of applying an adhesive material at affixing surfaces of the negative electrode material and the separator webs. The adhesive material is applied in the step (a1) such that a first coated section including a region where the adhesive material is applied with a coating weight M1 and a second coated section including a region where the adhesive material is applied with a coating weight M2 (≥ M1 + 0.02 g/m2) are located alternately in a longitudinal direction. The affixed body is cut within a range where the second coated section is located in the step (B). The positive electrode is located at a position opposite the first coated section.