Battery Separator Adhesive Layout for Better Electrolyte Infiltration
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Solution Overview
Problem
The adhesion between the electrode plate and the separator in lithium ion batteries is compromised by adhesive-coated separators, leading to poor electrolyte infiltration and increased direct current resistance (DCR) due to pore blockage, which also results in lithium precipitation.
Innovation Solution
Incorporating a first solvent and a first additive with a dielectric constant of ≤10 into the electrolyte, and adjusting the mass percentages and protruding heights of the adhesive layer in specific regions of the separator, ensuring the ratio (a+b)/(X/Y) satisfies 3≤(a+b)/(X/Y)≤60, enhances adhesion and improves electrolyte infiltration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an adhesive-coated separator is used to increase adhesion between the electrode plate and separator, then the adhesion is improved, but the pores of the separator are blocked causing poor electrolyte infiltration and increased DCR
Solution Approach 1:
The separator is designed with different adhesive layer protruding heights in different regions: the first region (exceeding the positive electrode plate) has a smaller protruding height to maintain pore openness for electrolyte infiltration, while the second region (between electrodes) has a larger protruding height to ensure strong adhesion. This local differentiation resolves the contradiction between adhesion and electrolyte infiltration.
Solution Approach 2:
The separator is divided into multiple regions with different adhesive layer characteristics. The adhesive layer itself is segmented into different height zones (X and Y) that perform different functions: one zone prioritizes electrolyte flow while the other prioritizes mechanical bonding, thus resolving the overall contradiction through functional segmentation.
2Strength
If the adhesive layer protruding height is increased to improve adhesion, then the adhesion is improved, but the porosity of the separator decreases leading to lithium precipitation
Solution Approach 1:
Different regions of the separator have different adhesive layer protruding heights to balance adhesion and porosity requirements. The first region maintains higher porosity to prevent lithium precipitation, while the second region provides sufficient adhesion strength, resolving the contradiction between these two parameters.
3Strength
If the adhesive layer is made thicker to improve adhesion, then the adhesion is improved, but the direct current resistance (DCR) of the battery increases
Solution Approach 1:
The adhesive layer thickness is optimized differently in different regions: thinner in the first region to maintain low DCR and good electrolyte infiltration, and thicker in the second region to provide sufficient adhesion. This spatial variation resolves the contradiction between adhesion strength and electrical resistance.
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 approach significantly improves adhesion between the separator and electrode plate, reduces DCR, and prevents lithium precipitation, thereby enhancing battery performance and safety.
Implementation Method 1
a first solvent and a first additive having a dielectric constant of ≤10 are added to the electrolyte of the battery
Data Source
AI summary
A battery comprises a separator. In the width direction of the separator, the separator further comprises a first region and a second region located between the positive and negative electrode plates. The protruding heights of the adhesive layers in the first and second regions are denoted as X and Y, respectively. The battery further comprises an electrolyte comprising a first solvent and a first additive each having a dielectric constant of ≤10. Based on the total mass of the electrolyte, the mass percentages of the first solvent and the first additive are denoted as a and b, respectively; and 3≤(a+b)/(X/Y)≤60 is satisfied, such that the adhesion between the separator and the electrode plate can be significantly improved, and the infiltration problem caused by the pore blockage by the adhesive layer of the separator can be effectively solved.