Vacuum Boiling Formation for Lead Acid Batteries
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Solution Overview
Problem
Current lead-acid battery formation processes face challenges in achieving short formation times and preventing organic component decomposition due to uneven conversion rates of electrodes and limited cooling efficiency, especially with AGM batteries, which require precise acid density control and heat dissipation.
Innovation Solution
The process involves conducting formation at the boiling point of the electrolyte under negative pressure, utilizing the latent heat of water to maintain a constant temperature and enhance acid exchange, allowing for lower initial acid densities and improved conversion rates, particularly for AGM batteries, without the need for external cooling systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If formation is carried out with acid circulation and cooling to achieve short formation times, then formation time is reduced, but the method cannot be used with AGM batteries with glass fleece separators
Solution Approach 1:
The invention changes the pressure parameter from atmospheric to negative pressure (vacuum), which fundamentally alters the formation mechanism. Under negative pressure, water evaporates at lower temperatures (50-60°C), providing cooling through latent heat of vaporization without requiring acid circulation. This enables AGM battery formation while maintaining short formation times.
Solution Approach 2:
The invention utilizes the phase transition of water from liquid to vapor at the boiling point under negative pressure. The evaporation process absorbs latent heat (540 kcal/kg), providing efficient cooling that prevents organic component decomposition while enabling fast formation. This phase transition mechanism replaces the acid circulation cooling system.
2Productivity
If formation is carried out at higher temperatures to achieve short formation times, then formation time is reduced, but organic components decompose
Solution Approach 1:
The invention exploits the phase transition of water at its boiling point under negative pressure. As water evaporates, it absorbs latent heat (540 kcal/kg), which automatically stabilizes the temperature at the boiling point (50-60°C under vacuum). This self-regulating thermal mechanism prevents temperature from rising to levels that would cause organic component decomposition while maintaining fast formation kinetics.
Solution Approach 2:
The formation process itself generates the cooling mechanism through water evaporation. The electrochemical reactions produce heat, which causes water to evaporate at the boiling point under negative pressure, and this evaporation absorbs the generated heat, self-regulating the temperature without external cooling systems.
3Loss of energy
If acid circulation is used for cooling, then heat dissipation is improved, but heat exchange only occurs on the surface of the plate set and acid cannot be exchanged in the plate sets due to glass fleece
Solution Approach 1:
The invention replaces the mechanical acid circulation system with a thermal phase change system. Instead of pumping acid through heat exchangers and relying on convection, the system uses water evaporation at the boiling point under negative pressure. The phase transition provides intense cooling (540 kcal/kg latent heat) that penetrates throughout the battery, bypassing the limitations of surface-only heat exchange and glass fleece restrictions.
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 method reduces formation time, minimizes organic component decomposition, and improves conversion efficiency, making it suitable for AGM batteries, with potential for reduced electrical energy consumption and manufacturing costs.
Implementation Method 1
When the water evaporates at the boiling point, the latent heat is removed or added without there being a change in temperature
Implementation Method 2
At the boiling point, the latent heat of water ensures a constant temperature with heat input of up to 540 kcal/kg of water
Implementation Method 3
the formation is carried out at the boiling point of the electrolyte
Implementation Method 4
The boiling point depends on external pressure. The boiling point is between approximately 50 to 60°C at a pressure of less than 500 mbar (50 kPa)
Implementation Method 5
the hydrogen gas formed during the formation at the negative electrode and the oxygen gas formed at the positive electrode immediately escape due to the volume increase in the vacuum
Data Source
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AI summary
The invention relates to a method for producing lead acid batteries at the boiling point of the electrolyte, having improved cooling during production. The boiling point can be adjusted by applying a vacuum. At the boiling point, the latent heat causes a cooling effect, and the temperature is determined by the applied vacuum and kept constant. The vacuum is conventionally selected to be under 500 mbar (50 kPa) and, in particular, between 100 and 200 mbar (10 and 20 kPa). The invention relates to an efficient cooling method for all lead acid battery types, such as wet cell, AGM and gel batteries. The cooling effect is greater than that achieved by cooling in a water bath or by acid recirculation. The method permits the production time to be reduced to a few hours, in particular for AGM batteries.