Lead-Acid Battery PSOC Charge Acceptance via Plate Surface Area
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Solution Overview
Problem
Flooded-type lead-acid batteries used in micro-hybrid vehicles face challenges in charge acceptance and service life due to intermittent charging and high-rate discharging in a partial state of charge, leading to reduced performance and shorter lifespan, as the existing methods primarily focus on improving the negative active material without effectively addressing the limitations of the positive active material.
Innovation Solution
The solution involves optimizing the configuration of both negative and positive active materials by adding a carbonaceous conductive material and an organic compound to the negative active material, and adjusting the total surface area of the positive active material per unit of plate pack volume to enhance charge acceptance and reduce reaction overvoltage, thereby improving the overall charge acceptance and service life of the battery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carbonaceous electrically conductive material is added to the negative active material to improve charge acceptance, then charge acceptance is improved, but the carbonaceous material bleeds into the electrolyte and causes internal short
Solution Approach 1:
The patent changes the chemical composition parameters of the negative active material by adding specific organic compounds (lignin sulfonate, formaldehyde condensate of bisphenol and aminobenzenesulfonic acid) that suppress carbonaceous material bleeding. These additives modify the electrochemical stability of the carbon particles, preventing them from detaching and contaminating the electrolyte while maintaining electrical conductivity and charge acceptance.
Solution Approach 2:
The patent creates a composite negative active material by combining carbonaceous electrically conductive material with specific organic compounds. This composite structure allows the carbon particles to be stabilized within the active material matrix, preventing their release into the electrolyte while maintaining the electrical conductivity necessary for improved charge acceptance.
2Adaptability or versatility
If the battery is used in partial state of charge to meet intermittent charging demands, then adaptability to micro-hybrid vehicles is improved, but service life is reduced due to lead sulfate coarsening
Solution Approach 1:
The patent modifies the chemical composition of the negative active material by adding organic compounds that suppress lead sulfate coarsening. These additives change the crystallization behavior of lead sulfate during charging and discharging cycles, preventing the formation of large, inactive sulfate crystals that would reduce capacity and service life under partial state of charge conditions.
Solution Approach 2:
The patent ensures continuous protective action against lead sulfate coarsening by incorporating organic compounds that continuously suppress sulfate crystal growth throughout repeated charging and discharging cycles. This continuous protection maintains the fine structure of lead sulfate and preserves charge acceptance even under intermittent charging conditions typical of micro-hybrid vehicles.
3Quantity of substance
If electrolyte concentration is high to increase energy density, then energy storage capacity is improved, but charge acceptance becomes increasingly difficult
Solution Approach 1:
The patent applies local quality improvement by adding carbonaceous electrically conductive material and organic compounds specifically to the negative active material. This localized enhancement of electrical conductivity at the negative electrode interface compensates for the reduced charge acceptance caused by high electrolyte concentration, allowing the battery to maintain both high energy density and good charge acceptance.
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 the charge acceptance and service life of the lead-acid battery by enhancing the performance of both negative and positive plates, allowing for high-rate discharge without hindrance and reducing the coarsening of lead sulfate, thus extending the battery's lifespan under partial state of charge conditions.
Implementation Method 1
added to the negative active material at least a carbonaceous electrically conductive material
Implementation Method 2
an organic compound which acts to suppress coarsening of the negative active material due to repeated charging and discharging
Implementation Method 3
lead-acid battery having a configuration in which a plate pack is accommodated in a container together with an electrolyte
Implementation Method 4
a flooded-type lead-acid battery having an electrolyte free from a plate pack and separator inside a container
Data Source
Figure 1~2
Figure 3~4
AI summary
A flooded-type lead-acid battery in which charging is intermittently carried out in a short period of time and high-rate discharge to a load is carried out in a partial state of charge, wherein the charge acceptance and service life characteristics under PSOC are improved by using a positive plate in which the total surface area of the positive active material per unit of the plate pack volume is set in a range of 3.5 to 15.6 m2/cm3; a negative plate with improved charge acceptance and service life performance obtained by adding a carbonaceous electrically conductive material, and a formaldehyde condensate of bisphenol and aminobenzene sulfonic acid to the negative active material; and a separator formed from a nonwoven in which a surface facing the negative plate is composed of material selected from glass, pulp, and polyolefin.