Lead Acid Battery Negative Electrode Carbon Material Blend
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Solution Overview
Problem
Lead-acid batteries used in partial state of charge (PSOC) conditions face challenges in maintaining high life performance due to the composition of the negative electrode material, particularly with carbon black aggregation hindering conductive network formation and charge efficiency.
Innovation Solution
Incorporating a carbon material blend with a first carbon material of 32 µm or more and a second carbon material of less than 32 µm, with a powder resistance ratio R2/R1 of 155 or less and a specific surface area ratio S2/S1 between 20 and 240, to enhance conductive network formation and charge efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carbon black is added to negative electrode material to improve conductivity, then electrical conductivity is improved, but carbon black aggregates and fails to form conductive network, reducing PSOC life performance
Solution Approach 1:
The patent uses a composite carbon material system combining graphite particles (3-50 μm) with carbon black (average primary particle size 0.02-0.2 μm). The graphite provides a backbone conductive network while carbon black fills gaps and enhances conductivity at interfaces, creating a synergistic effect that prevents aggregation and ensures stable PSOC life performance.
2Productivity
If carbon material is added to enhance conductive network formation, then charge efficiency is improved, but side reactions with electrolyte increase, reducing battery life
Solution Approach 1:
The patent optimizes the particle size parameters of carbon materials, using graphite with 3-50 μm particles and carbon black with 0.02-0.2 μm primary particles. This parameter control reduces excessive surface area that would cause side reactions while maintaining sufficient conductivity for high charge efficiency in PSOC conditions.
3Speed
If negative electrode material density is reduced to improve charge acceptance, then regenerative acceptance is improved, but conductive network formation becomes less likely, reducing PSOC life performance
Solution Approach 1:
The patent creates local conductive networks by distributing carbon materials heterogeneously in the negative electrode material. The graphite and carbon black form conductive pathways at critical locations (particle interfaces, active material boundaries) without requiring high overall density, enabling fast charge acceptance while maintaining PSOC life performance.
Data Source
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AI summary
A lead-acid battery includes a negative electrode plate, a positive electrode plate, and an electrolyte solution. The negative electrode plate contains a negative electrode material containing a carbon material. The carbon material contains a first carbon material having a particle size of 32 µm or more, and a second carbon material having a particle size of less than 32 µm. A ratio of powder resistance R2 of the second carbon material to powder resistance R1 of the first carbon material: R2/R1 is 155 or less.