Separator Dot Pattern Layer Prevents Electrode Separation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current lithium secondary battery separators with porous coating layers face issues of electrode-separator separation during assembly, leading to poor battery performance and safety risks due to thermal shrinkage and inorganic particle detachment, which can cause electric short circuits and explosions.
Innovation Solution
A separator with a porous coating layer made of a mixture of inorganic particles and a binder polymer, enhanced by a dot pattern layer of rubber-based polymer dots that improve adhesion between the electrode and separator while maintaining lithium ion transferability, using a styrene-butadiene copolymer with hydrophilic functional groups to enhance mechanical stability and prevent particle separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a porous coating layer containing inorganic particles is formed on the porous substrate, then thermal shrinkage resistance is improved, but adhesion between electrode and separator deteriorates
Solution Approach 1:
The patent uses a composite coating layer made of inorganic particles (such as alumina, silica, or titania) dispersed in a binder polymer matrix. This composite structure combines the thermal stability of inorganic particles with the adhesive properties of the polymer binder, achieving both thermal shrinkage resistance and good adhesion to the electrode.
Solution Approach 2:
The coating layer is designed with a porous structure that allows lithium ion transport while maintaining mechanical integrity. The porous morphology provides pathways for ion diffusion and reduces the density of the coating, preventing excessive rigidity that would harm adhesion, while still providing thermal stability through the inorganic particle network.
2Reliability
If a porous coating layer is formed on the porous substrate, then safety against thermal runaway is improved, but inorganic particles may detach and cause local defects
Solution Approach 1:
The inorganic particles are embedded in a binder polymer matrix that strongly adheres to both the porous substrate and the electrode. This composite structure anchors the inorganic particles firmly, preventing detachment during assembly and operation, while the inorganic network continues to provide thermal stability and prevent thermal runaway.
Solution Approach 2:
The coating layer exhibits spatially varying properties: regions with higher inorganic particle concentration provide enhanced thermal stability, while the binder polymer distribution ensures uniform adhesion and particle anchoring. This local optimization prevents particle detachment in critical areas while maintaining overall safety performance.
3Stability of the object's composition
If inorganic particles are used as spacers in the porous coating layer, then physical shape stability is improved, but lithium ion transfer efficiency deteriorates
Solution Approach 1:
The coating layer is designed with controlled porosity and interconnected pore channels that facilitate lithium ion diffusion. The inorganic particles are strategically positioned to provide structural support and shape stability while leaving sufficient pore space and continuous pathways for ion transport, balancing mechanical stability with ionic conductivity.
Solution Approach 2:
The patent optimizes parameters such as inorganic particle size, particle concentration, pore size, and porosity to achieve the right balance. By controlling these parameters, the coating provides adequate structural support through inorganic particles while maintaining sufficient pore connectivity and size for efficient lithium ion transfer, preventing performance deterioration.
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-separator separation and inorganic particle detachment, enhancing the mechanical stability and safety of lithium secondary batteries by maintaining adhesion and ion transferability, thereby improving battery performance and preventing thermal runaway.
Implementation Method 1
the inorganic particles 3 in the porous coating layer formed on the porous substrate 1 act as a kind of spacer that may keep a physical shape of the porous coating layer, so the inorganic particles 3 restrain thermal shrinkage of the porous substrate when the electrochemical device is overheated
Implementation Method 2
a porous coating layer made of a mixture of a binder polymer and inorganic particles is formed on the surface of a porous substrate
Implementation Method 3
the separator is an important component that plays a role of ion passage in the battery
Data Source
Figure 1~2
Figure 3~4
AI summary
The present invention provides a separator comprising a porous substrate having a plurality of pores; a porous coating layer formed on at least one surface of the porous substrate and made of a mixture of a plurality of inorganic particles and a binder polymer; and a dot pattern layer formed on a surface of the porous coating layer and having a plurality of dots which are made of polymer and are arranged at predetermined intervals. Also provided is an electrochemical device comprising the separator.