Porous Heat-Resistant Layer for Battery Module Pressure Management
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Solution Overview
Problem
Non-aqueous electrolyte secondary batteries, particularly those used in hybrid electric vehicles, face issues with electrolyte leakage due to pressure applied during module assembly, leading to reduced ion conductivity and battery performance.
Innovation Solution
A non-aqueous electrolyte secondary battery design featuring a porous heat-resistant layer with specific porosity and filler composition, attached to the electrodes, and a battery module structure with end plates and bridges to manage pressure, ensuring electrolyte retention and maintaining battery performance under size constraints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a resin-made separator is used in non-aqueous electrolyte secondary batteries, then the battery can operate with standard ion conductivity, but under pressure the non-aqueous electrolyte is forced out from the separator leading to loss of ion conductivity and declined battery performance
Solution Approach 1:
The invention uses a composite porous heat-resistant layer comprising inorganic filler particles (such as alumina, silica, or titania) dispersed in a binder resin matrix. This composite structure combines the mechanical strength and thermal stability of inorganic fillers with the binding and flexibility properties of the resin binder, creating a separator that resists electrolyte leakage under pressure while maintaining ion conductivity.
Solution Approach 2:
The invention employs a porous heat-resistant layer with controlled porosity (30-80%) that allows ion transport while providing structural support. The porous structure is formed by dispersing inorganic filler particles and removing the solvent, creating a network of interconnected pores that facilitate electrolyte flow and ion conduction while the inorganic framework prevents excessive electrolyte expulsion under pressure.
2Quantity of substance
If batteries are bound in battery modules to achieve high capacity, then module dimension can be controlled, but the binding force forces the non-aqueous electrolyte out from the separator in center area batteries
Solution Approach 1:
The composite porous heat-resistant layer with inorganic filler reinforcement provides enhanced mechanical strength to withstand the binding forces in battery module centers. The inorganic filler network distributes and absorbs the compressive stress from module binding, preventing the separator from deforming enough to force electrolyte out, thereby protecting center-area batteries from electrolyte loss while maintaining high capacity.
Solution Approach 2:
The porous heat-resistant layer acts as a pre-established protective barrier that cushions the separator against binding forces before electrolyte leakage can occur. The inorganic filler particles and porous structure are designed in advance to absorb and distribute mechanical stress, preventing the harmful effect of electrolyte expulsion under module binding conditions.
3Duration of action of moving object
If the electrodes expand during charging, then the battery case tries to expand, but in bound battery modules the batteries cannot freely change shape causing load concentration on center batteries
Solution Approach 1:
The composite porous heat-resistant layer combines the expandability needed for charge-discharge cycles with the mechanical strength to resist binding forces. The inorganic filler particles provide a rigid framework that maintains structural integrity under stress, while the porous resin matrix allows for volume changes during charging, enabling the battery to accommodate electrode expansion without excessive stress concentration in center positions.
Solution Approach 2:
The invention changes the mechanical parameters of the separator by incorporating inorganic fillers with appropriate particle sizes (1-10 μm) and controlling the binder content (5-50 parts by weight per 100 parts filler). This creates a separator with optimized elasticity and strength parameters that can accommodate volume changes during charging while resisting the binding forces in module centers, reducing load concentration.
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 electrolyte leakage, maintains high ion conductivity, and enhances cycle life and reliability of the batteries, even under high pressure conditions, suitable for high-capacity applications like hybrid electric vehicles.
Implementation Method 1
a porous heat-resistant layer which keeps a sufficient amount of the non-aqueous electrolyte
Implementation Method 2
ion conductivity is lost in the separator to decline the battery performance
Data Source
AI summary
A non-aqueous electrolyte secondary battery including an electrode assembly, a non-aqueous electrolyte, and a substantially rectangular battery case for housing the electrode assembly and the non-aqueous electrolyte. The thickness α, the width β, and the height γ of the battery case satisfy the relation α<β≦γc. The electrode assembly includes a positive electrode, a negative electrode, and a porous heat-resistant layer disposed between these electrodes. The positive electrode includes a positive electrode active material layer, and the negative electrode includes a negative electrode active material layer. The ratio of the pore volume included in a predetermined area of the porous heat-resistant layer to the battery theoretical capacity is 0.18 to 1.117 ml/Ah. The predetermined area has the same area as the positive electrode active material layer. The porosity of the porous heat-resistant layer is 35 to 85%.