Secondary Battery Electrode Plate Induction Annealing for Flatness
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Solution Overview
Problem
The manufacturing process of electrode plates for secondary batteries often results in bending or deflection due to the thickness difference between the active material coated and uncoated portions, leading to reduced battery life and potential internal short-circuits.
Innovation Solution
An induction heating annealing method is applied to the uncoated portion of the electrode plate, using an apparatus with specific rollers and heating coils to treat the uncoated area, altering its material properties and reducing the pressure difference when rolled.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the active material is coated on the electrode plate and then rolled under high pressure, then the coated portion is compressed to form the electrode structure, but the coated portion becomes greatly elongated due to thickness difference between coated and uncoated portions
Solution Approach 1:
The patent applies induction heating to change the temperature parameter of the uncoated portion, which modifies the material properties (elongation characteristics) of the collector in that region. By heating the uncoated portion to a specific temperature range, the material becomes more ductile and can elongate without causing bending or deflection during the rolling process, thus resolving the contradiction between achieving proper electrode compression and maintaining plate flatness
Solution Approach 2:
The patent applies different treatments to different portions of the electrode plate: the coated portion is compressed under high pressure while the uncoated portion is selectively heated by induction heating. This creates local quality differences where the uncoated portion has modified elongation properties, allowing it to accommodate the compression of the coated portion without causing overall plate deformation. The local heating treatment ensures that only the necessary region (uncoated portion) is modified, preserving the integrity of the coated active material region
2Reliability
If the uncoated portion is not treated, then the manufacturing process is simple, but the electrode plate bends or deflects due to pressure difference between coated and uncoated portions
Solution Approach 1:
The patent replaces a potentially complex mechanical treatment system with an induction heating system. Instead of using complex mechanical devices to pre-compress or pre-shape the uncoated portion, the invention uses electromagnetic induction heating to thermally modify the material properties. This substitution simplifies the manufacturing process while achieving the desired reliability, as induction heating equipment is more straightforward than complex mechanical pre-treatment systems
Solution Approach 2:
The patent performs induction heating of the uncoated portion as a preliminary action before the rolling compression step. By pre-heating the uncoated portion to modify its material properties, the electrode plate is prepared in advance to withstand the subsequent high-pressure rolling without bending. This preliminary thermal treatment ensures that when the coated portion is compressed, the uncoated portion can accommodate the stress, preventing deflection and ensuring battery reliability
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 method effectively prevents bending and deflection of the electrode plate, enhancing battery performance and longevity by ensuring uniform rolling and reducing the risk of internal short-circuits.
Implementation Method 1
an induction heating annealing part for treating the uncoated portion of the electrode plate transferred from the guide roller
Data Source
Figure 1~2a
Figure 2b~2c
Figure 2d~3a
AI summary
The present invention refers to an electrode plate for a secondary battery including a collector having a coated portion on which an active material is coated; and an uncoated portion extending in a longitudinal direction along one or both sides of the coated portion. The invention further relates to an induction heat annealing apparatus and a method of manufacturing the electrode plate by use of the apparatus.