Lead-Acid Battery Electrolyte Segmentation for Stratification Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lead-acid batteries experience acid stratification due to the electrolyte volume above the electrodes, leading to accelerated aging and reduced service life, particularly in vented batteries where the electrolyte binding exacerbates this issue.
Innovation Solution
The electrolyte volume above the electrodes is reduced by dividing it into separate parts connected with a diffusion barrier, such as a thin fluid path or semi-permeable membrane, allowing for automatic refilling by gravity while inhibiting sulfate ion diffusion, thus reducing acid stratification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If electrolyte volume above the electrodes is increased to enable automatic refilling, then refilling capability is improved, but acid stratification is worsened
Solution Approach 1:
The electrolyte volume is divided into two separate parts: a first volume between the electrodes and a second volume above the electrodes. These two volumes are connected through a diffusion barrier that allows gravitational flow but restricts diffusion, enabling automatic refilling while preventing acid stratification between the electrodes.
Solution Approach 2:
A diffusion barrier is introduced as an intermediary element between the two electrolyte volumes. This barrier mediates the interaction by allowing controlled gravitational refilling while blocking the diffusion process that causes acid stratification, thus resolving the contradiction between refilling capability and stratification prevention.
2Duration of action of stationary object
If electrolyte volume above the electrodes is reduced to minimize acid stratification, then battery lifespan is improved, but refilling capability is worsened
Solution Approach 1:
The electrolyte system is segmented into a first volume (between electrodes) and a second volume (above electrodes), connected via a diffusion barrier. This segmentation allows the first volume to remain small (reducing stratification) while the second volume provides sufficient electrolyte for refilling through controlled diffusion.
Solution Approach 2:
Different regions of the electrolyte system are given different properties: the first volume between electrodes has restricted diffusion (low sulfate ion concentration changes) to prevent stratification, while the second volume above electrodes has free diffusion capability to ensure adequate refilling supply.
3Reliability
If diffusion barrier is introduced to separate electrolyte volumes, then acid stratification is reduced, but device complexity is increased
Solution Approach 1:
The diffusion barrier is implemented as a thin film or membrane structure that separates the two electrolyte volumes. This thin-film approach achieves the diffusion restriction function with minimal structural complexity, allowing gravitational refilling while blocking sulfate ion diffusion that causes stratification.
Solution Approach 2:
The diffusion barrier utilizes porous material properties to achieve selective permeability - allowing water and acid molecules to pass through for refilling while restricting larger sulfate ion diffusion. This porous structure accomplishes the stratification prevention function with relatively simple material selection.
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 extends the cyclic life of lead-acid batteries by up to a factor of 4 or 5, simplifies diagnostics, decouples water consumption from performance, and prevents corrosion-induced short circuits by spatially separating electrolyte and gases.
Implementation Method 1
these partial volumes are connected to each other by a strong diffusion barrier, for example, by a thin and/or long fluid connection path and/or an omni- or semi-permeable membrane
Implementation Method 2
the electrolyte volume is divided, and these partial volumes are connected to each other... allowing for automatic refilling by gravity
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a lead-acid battery with liquid electrolyte, in particular a lead-acid battery. The inventor has now surprisingly discovered that the electrolyte volume above the electrodes is detrimental, especially to the aging behavior, and should be reduced. The object of the invention is therefore to provide a method or a battery for reducing acid stratification. This object is achieved in particular by reducing the electrolyte volume directly above the electrodes. Nevertheless, automatic refilling, preferably by gravity alone, should remain possible. For this purpose, the electrolyte volume is divided, and these partial volumes are connected to each other by a strong diffusion barrier, for example, by a thin and/or long fluid connection path and/or an omni- or semi-permeable membrane.This allows the amount available for automatic refilling to be significantly increased without any disadvantage.