Positive Electrode Additive for Internal Short-Circuit Heat Blocking
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Solution Overview
Problem
Existing secondary battery positive electrodes with high energy density suffer from safety issues due to internal short circuits, leading to excessive Joule heat generation and resistance increases, which deteriorate battery performance.
Innovation Solution
Incorporating a thermal decomposable additive, such as acetamidobenzoic acid, into the positive electrode active material layer to selectively increase resistance at high temperatures during an internal short circuit, thereby blocking conductive paths and preventing excessive temperature rise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a coarser porous body is used as a battery current collector, then production cost decreases and manufacturing ease improves, but surface area decreases and contact with electrode material becomes insufficient
Solution Approach 1:
The patent applies porous materials by forming a porous coating layer on the battery current collector that contains porous particles with specific pore volume (0.4-0.7 mL/g) and average pore diameter (0.03-0.08 μm). This porous structure increases the effective surface area available for electrode material contact while maintaining a coarse substrate structure for cost-effective production. The porous coating layer provides numerous micro-pores that enhance interfacial contact between the current collector and electrode material without requiring the entire substrate to be finely structured.
Solution Approach 2:
The patent employs composite materials by combining a coarse battery current collector substrate with a porous coating layer containing porous particles, conductive particles, and binder. This composite structure allows the coarse substrate to provide mechanical strength and cost-effectiveness while the porous coating layer provides high surface area and enhanced electrochemical activity. The composite approach resolves the contradiction by distributing functions across different material layers with optimized properties for each function.
2Area of stationary object
If a finer porous body is used as a battery current collector, then surface area increases and contact with electrode material improves, but production cost increases and manufacturing complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the current collector into two distinct functional layers: a coarse substrate layer that is easy and inexpensive to manufacture, and a porous coating layer that provides the high surface area. The porous coating layer is further segmented into porous particles, conductive particles, and binder components. This segmentation allows each layer to be optimized independently for its specific function while maintaining overall manufacturing feasibility.
Solution Approach 2:
The patent implements local quality by concentrating the high surface area requirement locally in the porous coating layer rather than throughout the entire current collector structure. The coarse substrate maintains its simple, cost-effective structure while the porous coating layer applied to its surface provides the necessary high surface area and electrochemical activity. This local optimization of quality where needed resolves the contradiction between surface area and manufacturing ease.
3Strength
If porous particles are sintered at high temperature (900-1500°C), then particle strength increases, but production energy consumption increases and fine particles may be lost
Solution Approach 1:
The patent applies parameter changes by optimizing the sintering temperature range to 900-1500°C, which is a specific parameter window that balances particle strength development with energy consumption and particle retention. This parameter optimization ensures sufficient mechanical strength of porous particles for handling and electrode formation while minimizing excessive energy input and preventing fine particle loss through vaporization or ejection during the sintering process.
4Area of stationary object
If porous particles with small average pore diameter (0.03-0.08 μm) are used, then contact area with electrode material increases, but production precision requirements increase
Solution Approach 1:
The patent applies porous materials with specifically controlled pore dimensions (average pore diameter 0.03-0.08 μm and pore volume 0.4-0.7 mL/g) that provide high contact area with electrode material. The porous structure naturally creates extensive internal surface area through its interconnected pore network, achieving high contact area without requiring extremely precise control of external particle geometry. The pore size range is optimized to balance contact area with manufacturability of the porous particles.
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 maintains low resistance at room temperature while effectively increasing internal resistance at high temperatures, ensuring both safety and good battery performance by preventing excessive heat generation during short circuits.
Implementation Method 1
porous particles having a pore volume of 0.4 mL/g to 0.7 mL/g and an average pore diameter of 0.03 μm to 0.08 μm
Implementation Method 2
conductive particles
Implementation Method 3
binder
Data Source
Figure 1
AI summary
A positive electrode for a secondary battery including a positive electrode current collector, and a positive electrode active material layer supported on the positive electrode current collector. The positive electrode active material layer contains active material particles, a binder, and a thermal decomposable additive, and the thermal decomposable additive includes an acetamidobenzoic acid.