Columnar Battery Electrode Protrusions for Inner-Turn Deformation
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Solution Overview
Problem
Columnar secondary batteries, such as lithium-ion batteries, face increased electrochemical impedance and risk of lithium plating due to inward deformation of electrode plates at inner turns during cycling, leading to deteriorated cycle performance.
Innovation Solution
The design includes an electrode plate with a first material layer featuring protrusions on a specific section, controlled proportions, and spacings to maintain appropriate distances between electrode plates, reducing inward deformation and impedance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If full-tab smooth-out flattening technology is used, then the battery structure is simplified and manufacturing is easier, but the electrode plate deforms inward during cycling, increasing electrochemical impedance and lithium plating risk
Solution Approach 1:
The patent applies local quality by creating protrusions only at specific locations (inner turns of the electrode assembly) rather than uniformly across the entire electrode plate. These localized protrusions provide targeted support where deformation occurs most severely, maintaining manufacturing simplicity while improving reliability at critical stress points.
Solution Approach 2:
The protrusions are pre-formed on the electrode plate before assembly, serving as preventive measures against inward deformation. This preliminary structural modification ensures that the electrode plate maintains its shape during cycling, addressing the reliability issue before the deformation problem actually occurs.
2Quantity of substance
If the electrode plate expands during cycling, then the battery capacity increases, but the inner turn electrode plate deforms inward, increasing electrochemical impedance
Solution Approach 1:
The protrusions provide preliminary counter-action to the inward deformation force generated during electrode expansion. By having these structural supports pre-positioned at the inner turns, the patent prevents the harmful deformation effect while allowing the beneficial capacity increase from electrode material expansion.
Solution Approach 2:
The patent modifies the geometric parameters of the electrode plate by adding protrusions with specific dimensions (height, width, spacing). These parameter changes create structural rigidity at critical locations, enabling the electrode to accommodate material expansion without developing harmful inward deformations that increase impedance.
3Reliability
If protrusions are added to the electrode plate, then inward deformation is reduced and cycle performance improves, but manufacturing complexity increases
Solution Approach 1:
The protrusions are implemented only at specific critical locations (inner turns) rather than uniformly across the entire electrode plate. This localized approach improves cycle performance by addressing deformation at problem areas while minimizing the overall structural complexity and manufacturing burden.
Solution Approach 2:
The patent applies partial action by adding protrusions only where most needed (inner turns experiencing maximum deformation stress) rather than providing uniform reinforcement across the entire electrode. This selective approach achieves sufficient reliability improvement without excessive manufacturing complexity.
Data Source
AI summary
A columnar secondary battery includes an electrode assembly. The electrode assembly includes an electrode plate. The electrode plate includes a current collector and a first material layer. The first material layer is located on a surface of the current collector facing away from a winding center of the electrode assembly. Along a length direction of the electrode plate and along a winding direction of the electrode assembly, the first material layer includes a first section and a second section connected sequentially. Based on a length of the first material layer, a length of the first section accounts for a proportion of L, 2%≤L≤20%. A plurality of protrusions are formed on a surface of the first section alone on the electrode plate.