Lithium Carbonate Cathode Additive for Battery Overcharge Venting
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Solution Overview
Problem
Lithium secondary batteries are prone to explosion or fire due to overcharging, which causes irreversible damage to cell components and poses safety risks.
Innovation Solution
The use of lithium carbonate particles with specific size and surface area distributions, prepared through a two-stage milling process involving zirconium oxide, enhances the generation of carbon dioxide gas during overcharging, thereby interrupting the current and preventing overcharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium secondary batteries are charged normally, then energy storage capacity is improved, but overcharging causes explosion or fire hazards
Solution Approach 1:
Lithium carbonate particles are pre-added to the cathode structure before battery operation. When overcharging occurs, these particles rapidly decompose to generate CO2 gas, which increases internal pressure and triggers the safety valve to interrupt current flow, preventing explosion or fire hazards before they can develop
Solution Approach 2:
The harmful effect of overcharging (excessive current flow) is converted into a beneficial safety mechanism. The increased current during overcharging accelerates the decomposition of lithium carbonate particles, generating CO2 gas that activates the pressure-release mechanism to stop the harmful current flow, thus transforming the overcharging hazard into a protective action
2Productivity
If lithium carbonate particle size is reduced to increase surface area, then CO2 generation speed is improved, but manufacturing complexity increases
Solution Approach 1:
The patent specifies precise particle size parameters (Dv50: 0.08-0.43 μm, Dn50: 0.015-0.5 μm) and surface area parameters (BET: 10-25 m2/g) for lithium carbonate particles. These controlled parameter ranges optimize CO2 generation speed while providing clear manufacturing specifications that balance performance requirements with production feasibility
Solution Approach 2:
The patent uses a relatively small amount of lithium carbonate (0.2-1.2 wt%) in the cathode composition. This partial addition is sufficient to provide effective overcharge protection through rapid CO2 generation, avoiding the need for excessive particle processing that would increase manufacturing complexity
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 lithium carbonate particles effectively prevent overcharging by increasing pressure within the battery, leading to current interruption and ensuring safety.
Implementation Method 1
enhances the generation of carbon dioxide gas during overcharging
Implementation Method 2
The lithium carbonate particles may have a Dv (50) between 0.08 μm and 0.43 μm. The lithium carbonate particles may have a BET surface area between 10 m2/g and 25 m2/g
Data Source
AI summary
Exemplary lithium carbonate (Li2CO3) particles may comprise at least 98% by weight (wt %) lithium carbonate. Exemplary lithium carbonate (Li2CO3) particles may have a Dv (50) between 0.08 μm and 0.43 μm. Exemplary lithium carbonate (Li2CO3) particles may have a Dn (50) between 0.015 μm and 0.5 μm. Exemplary lithium carbonate (Li2CO3) particles may have a BET surface area between 10 m2/g and 25 m2/g. Exemplary batteries may comprise a cathode, an anode, a separator sheet, and a non-aqueous electrolyte. Exemplary cathodes may have a cathode active material layer including a cathode active material and a plurality of lithium carbonate (Li2CO3) particles.