Cathode Plate Conductive Coating for Peel Strength and Cycle Stability
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Solution Overview
Problem
Lithium-ion batteries face issues with safety performance and cycle life due to the stripping of the cathode active material layer from the current collector, caused by the conductive coating during the cold pressing process, leading to electrode breakage and reduced cycle performance.
Innovation Solution
A cathode plate design featuring a conductive coating with a conductive agent content of 20-50% and a binder content of 50-80%, which alleviates damage to the oxide layer on the aluminum foil, enhances tensile strength, and improves electronic conduction and peel strength, thereby stabilizing the cathode active layer and enhancing cycle performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conductive coating is applied to the current collector, then electronic conduction between the current collector and cathode active material is improved, but the cathode active material layer becomes easily stripped during cold pressing
Solution Approach 1:
The patent adjusts the weight ratio parameters of conductive agent (20-50%) and binder (50-80%) in the conductive coating to optimize both electronic conduction and adhesion properties, resolving the contradiction between conductivity and peel strength
Solution Approach 2:
The conductive coating is formulated as a composite material containing both conductive agent and binder components, where the binder provides adhesion strength while the conductive agent ensures electronic conduction, thus simultaneously addressing both requirements
2Reliability
If the conductive coating contains high conductive agent content, then electronic conduction is enhanced, but the peel strength and stability of the coating decrease
Solution Approach 1:
The patent establishes specific parameter ranges for conductive agent (20-50% by weight) and binder (50-80% by weight) to balance electronic conduction capability with coating stability and adhesion, preventing both over-conduction that would weaken the coating and under-conduction that would reduce performance
3Strength
If the cathode active material layer adheres strongly to the current collector, then electrode breakage is prevented, but the cycle performance and service life are reduced due to oxidation
Solution Approach 1:
The conductive coating serves as an intermediary layer between the cathode active material and current collector, providing both adhesion strength to prevent breakage and protection against oxidation that would otherwise reduce cycle performance and service life
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
The solution effectively prevents electrode breakage, improves cycle stability, and enhances high-temperature stability and energy density of secondary batteries by ensuring stable adhesion and conductivity of the cathode active material layer.
Implementation Method 1
by controlling the amounts of the conductive agent and the binder, not only is the stability of electronic conduction between the current collector and the cathode active material ensured
Implementation Method 2
the peel strength between the current collector and the conductive coating is enhanced, thereby effectively solving the problem of the stripping of the cathode active layer
Data Source
AI summary
The present application provides a cathode plate, a secondary battery, a battery module, a battery pack, and an electric device. The cathode plate includes: a current collector, a conductive coating, and a cathode active layer. The conductive coating is arranged on at least one surface of the current collector. The conductive coating includes a conductive agent having a weight content of 20% to 50% and a binder having a weight content of 50%˜80%. The cathode active layer is arranged on a surface of the conductive coating away from the current collector, and a cathode active material in the cathode active layer is at least one of a lithium manganate-based cathode material, a ternary cathode material, and a quaternary cathode material.