Grooved Electrode Plate Welding for Stronger Battery Tab Joints
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Solution Overview
Problem
Lithium-ion batteries face reliability issues due to low welding strength between the tab and the electrode plate, resulting in reduced energy density and reliability of the battery.
Innovation Solution
The electrode plate design includes a current collector with a first and second active material layer, where the tab is welded into a groove on the current collector, forming a welding mark with integrated solder joints to enhance the welding strength and electrical connection between the tab and the current collector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a tab is welded to the electrode plate using conventional methods, then the electrode plate can be assembled, but the welding strength between the tab and the electrode plate is low resulting in reduced reliability
Solution Approach 1:
The patent applies local quality by creating a groove structure at the specific welding location on the electrode plate. This groove concentrates the welding interaction at a localized area, allowing the welding material to form a deeper, more intimate bond with the electrode plate surface. The groove geometry (with specific depth and width ratios) ensures that the welding strength is enhanced precisely where needed, without affecting other areas of the electrode plate.
Solution Approach 2:
The patent implements the nesting principle by having the welding mark structure contain multiple hierarchical levels: the groove is nested within the electrode plate body, the welding material is nested within the groove, and the tab is nested within the welding material structure. This nested arrangement creates a multi-layered bonding interface that significantly enhances the overall welding strength and reliability of the connection.
2Reliability
If the welding strength between tab and electrode plate is increased, then reliability improves, but the energy density of the battery decreases
Solution Approach 1:
The patent applies parameter changes by optimizing the groove dimensions (depth, width, and depth-to-width ratio) and the welding material composition. By carefully controlling these parameters, the welding strength is enhanced to improve reliability while minimizing the volume occupied by the welding material. This ensures that the groove does not excessively reduce the active material volume, thereby maintaining high energy density.
Solution Approach 2:
The local quality principle is applied by concentrating the welding enhancement措施 in a localized groove structure rather than uniformly increasing material throughout the electrode plate. This localized approach allows for improved welding strength at the tab connection point without significantly impacting the overall energy density of the battery, as the groove occupies minimal space relative to the total electrode plate volume.
3Strength
If a groove structure is created in the active material layer to enhance welding, then welding strength improves, but the manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by forming the groove structure in the active material layer before the welding process. This pre-formed groove serves as a prepared receptacle for the welding material, ensuring that when welding occurs, the material is already positioned optimally to create a strong bond. This preliminary structuring simplifies the welding operation itself and ensures consistent welding quality.
Solution Approach 2:
The patent optimizes manufacturing ease by controlling the groove parameters within specific ranges (depth-to-width ratio between 0.5 and 2.0, depth between 1-10 micrometers). These controlled parameters ensure that the groove can be efficiently formed using standard manufacturing techniques while still achieving the desired welding enhancement, thus balancing manufacturing simplicity with welding strength improvement.
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 design significantly improves the welding strength and reliability of the electrode plate, leading to increased energy density and performance of the lithium-ion battery.
Implementation Method 1
the tab is welded to the current collector in the groove to form a welding mark, the welding mark includes a first solder joint and a second solder joint, the first solder joint is located on the tab, the second solder joint is located on the current collector, and the first solder joint and the second solder joint are integrally fused and connected
Data Source
AI summary
An electrode plate includes: an electrode plate body and a tab, the electrode plate body includes a current collector, a first active material layer and a second active material layer; the first active material layer is provided with a groove, a bottom wall of the groove is a first functional surface of the current collector; and the tab is welded to the current collector in the groove to form a welding mark, the welding mark includes a first solder joint and a second solder joint, the first solder joint is located on the tab, the second solder joint is located on the current collector, and the first solder joint and the second solder joint are integrally fused and connected, which effectively enhances a welding strength between the tab and the current collector, so that a reliability of the electrode plate after welding is relatively high.