Lead Acid Battery Separator for Stop Start Efficiency
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Solution Overview
Problem
Traditional lead acid batteries are inefficient in hybrid vehicles due to sulphation phenomena, limited recharging efficiency at high rates, and inability to operate effectively in partially charged states, leading to reduced operativity and high water consumption.
Innovation Solution
The high efficiency lead acid battery features a porous separator with a polyethylene outer layer and non-woven polyester inner layer, carbon-based materials in the negative active mass, and a lead-tin alloy coating to reduce corrosion and sulphation, along with a larger electrolyte reserve to manage high charging rates and partial charging conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional lead acid battery configuration is used, then manufacturing cost is low and structure is simple, but recharging efficiency at high rates is limited and sulphation phenomena occur
Solution Approach 1:
The patent employs porous separators made of polyethylene and polyester materials with specific porosity characteristics to improve recharging efficiency. The porous structure allows better ion transport during high-rate charging while preventing sulphation by maintaining proper electrolyte distribution around the plates.
Solution Approach 2:
The invention uses composite separator structures combining polyethylene and polyester layers, each providing different functional properties. The polyethylene layer provides thermal stability and basic separation, while the polyester layer enhances porosity and ion conductivity, together resolving the contradiction between recharging efficiency and structural simplicity.
2Reliability
If traditional lead acid battery is used, then water consumption is low, but ability to operate in partially charged states is poor due to sulphation
Solution Approach 1:
The patent modifies the separator porosity parameters and electrolyte composition to prevent sulphation during partial charging cycles. By optimizing the porosity range and electrolyte additives, the battery can operate reliably in partially charged states without excessive water consumption or sulphation buildup.
3Power
If high charging rates are applied to traditional battery, then power delivery is improved, but secondary gasification reactions increase and recharging efficiency decreases
Solution Approach 1:
The porous separator structure with optimized pore size and distribution enables efficient ion transport during high-rate charging, reducing polarization effects and minimizing secondary gasification reactions. This allows the battery to deliver high power while maintaining recharging efficiency.
4Adaptability or versatility
If battery operates in Stop & Start cycles with high charging/discharging rates, then hybrid vehicle requirements are met, but sulphation accumulates and operativity is reduced
Solution Approach 1:
The composite separator structure combines materials with complementary properties that specifically address Stop & Start cycle requirements. The layered polyethylene-polyester construction provides both the mechanical stability needed for high-rate cycling and the porosity characteristics that prevent sulphation accumulation, ensuring long-term operativity in hybrid vehicle applications.
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 battery achieves efficient recharging and prolonged operation in hybrid vehicles, maintaining functionality after 750 cycles with deep discharges and high rates, while reducing corrosion and water consumption, ensuring reliability and economic production.
Implementation Method 1
each positive electrode (22) is enclosed inside a porous separator, formed of two overlaid layers, the first of which outermost in relation to the positive electrode, is made of polyethylene, while the second and innermost layer in relation to said positive electrode is made of non woven polyester
Implementation Method 2
the flags projecting from the top of the positive and negative electrodes are subjected to a treatment suitable for respectively reducing the corrosion and sulphation phenomena
Implementation Method 3
the ability to operate efficiently in partially charged states is in fact one of the main limitations of the traditional lead battery on account of the sulphation phenomena of the negative plates which drastically reduces the ability of the batteries to recharge
Data Source
Figure 1~4
AI summary
A high efficiency lead acid battery with liquid electrolyte for the Stop &Start cycle (10),especially suitable for equipping hybrid-electric class vehicles, comprises a container body or monobloc (12) in plastic material sub-divided internally into a plurality of cells (14) in which one or more negative plates or electrodes (28) and one or more positive plates or electrodes (22) are positioned, immersed in an electrolyte and delimited by porous separators; the electrodes (22-28) are electrically connected, between the various cells (14) constituting the monobloc by means of electrode/electrode and cell/cell connection elements (40). Said battery further comprises a cover (16) which closes so as to hermetically seal the container body (12), is fitted with plugs (20) which close the accesses to the cells (14) and incorporates the truncated cone terminals (18).The separator, positioned between the different electrodes, alternatively positive and negative (22-28), is formed of two overlaid layers (24), (26), the first of which outermost in relation to the positive electrode (22) and made of polyethylene, while the second and innermost layer (26) in relation to said positive electrode is made of non woven polyester having a thickness of 0.1 to 1.0 mm at 5 kPa. The containment layer of each negative plate or electrode (28) is composed of stratified, polyester-based non woven, present in a quantity of not less than 60%.