Battery Box Flap Design for Acid Stratification Control

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing battery technologies face inefficiencies in preventing acid stratification in lead-acid batteries due to sulfuric acid gradients, which can lead to irreversible damage, and current methods for circulation, such as thermal circulation, gassing, and pumping, require significant energy or complex handling.

Innovation Solution

A battery design featuring a dividing wall with a flap in the upper area that, when combined with adjacent inner walls, forms a flow path to enhance hydrostatic pumping, allowing electrolyte liquid to slosh and flow downwards, effectively mixing and reducing acid stratification without complex measures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If thermal circulation or gassing methods are used to prevent acid stratification, then acid mixing is improved, but energy consumption increases and electrolyte loss occurs

Engineering Contradiction:
Improveacid stratificationVSAvoidenergy consumption
Core Design Contradiction:
Stability of the object's compositionVSUse of energy by moving object

Solution Approach 1:

The battery case structure itself serves as the mixing mechanism through hydrostatic pumping during normal operation, eliminating the need for external energy input. The sloshing movements during vehicle operation automatically drive electrolyte circulation and prevent stratification without consuming additional energy.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces thermal circulation systems or gassing mechanisms with a purely mechanical hydrostatic pumping system based on sloshing movements, eliminating complex mechanical components and reducing energy requirements while effectively preventing acid stratification.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Stability of the object's composition

If pumps are used to circulate electrolyte, then acid stratification is reduced, but device complexity increases

Engineering Contradiction:
Improveacid stratificationVSAvoidpump mechanism complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The battery case structure itself serves as the mixing mechanism through hydrostatic pumping during normal operation, eliminating the need for external energy input. The sloshing movements during vehicle operation automatically drive electrolyte circulation and prevent stratification without consuming additional energy.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces thermal circulation systems or gassing mechanisms with a purely mechanical hydrostatic pumping system based on sloshing movements, eliminating complex mechanical components and reducing energy requirements while effectively preventing acid stratification.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If conventional dividing wall flow paths are used, then some electrolyte circulation occurs, but mixing effectiveness is insufficient

Engineering Contradiction:
Improveflow path structureVSAvoidelectrolyte mixing effectiveness
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The patent introduces dynamic elements (sloshing movements) into the electrolyte circulation system, transforming the static flow path into an active mixing system that adapts to vehicle operation conditions, thereby significantly improving mixing effectiveness while maintaining structural simplicity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent utilizes hydrostatic pumping principles to create effective electrolyte circulation, leveraging fluid dynamics and pressure gradients generated during vehicle motion to drive thorough mixing without requiring complex mechanical pumping systems.

Inventive Principle:
Principle #29Pneumatics and hydraulics

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 design effectively counteracts acid stratification using constructive improvements within the battery box, promoting efficient electrolyte circulation and mixing, thereby reducing the risk of damage while minimizing energy consumption and design complexity.

Implementation Method 1

using a hydrostatic pumping effect, unwanted acid stratification is effectively counteracted

Methodology Applied
Scientific EffectHydrostatic pumping: Hydraulic Press

Implementation Method 2

the sloshing movement of the electrolyte liquid that occurs when accelerating/braking or cornering is used to convey battery acid from above into the lower part of the respective cells

Methodology Applied
Scientific EffectSloshing movement: Turbulence

Implementation Method 3

diffusion processes equalize the different acid densities within certain limits

Methodology Applied
Scientific EffectDiffusion: Diffusion

Implementation Method 4

The sulfuric acid, which is heavier than water, sinks under the influence of gravity towards the bottom of the battery. This increases the concentration in the lower area of ​​the battery, which leads to so-called acid stratification

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP2617086B1Battery, battery box, and method for producing a battery
Publication Date: 2018.08.15 AKKUMULATORENFABRIK MOLL GMBH & CO KG
  • EP2617086B1 patent drawingFigure 1
  • EP2617086B1 patent drawingFigure 2
  • EP2617086B1 patent drawingFigure 3

AI summary

The invention relates to a battery for motor vehicles, comprising a battery box (2) divided into cells (1), electrode plates (3) arranged in the cells (1), an electrolyte liquid (4) that surrounds the electrode plates (3), and a device for mixing the electrolyte liquid (4) in the cells (1). The device comprises a partition that forms a flow path (10) which is separated from the electrode plates (3) and which fluidically connects an upper region to a lower region of the cell (1). The invention is characterized in that the partition (5) has a flap (7) in the upper region, said flap extending preferably across the entire width of the partition (5) and defining a part of the flow path (10) together with adjoining inner walls (6) of the battery box (2). The invention likewise relates to a battery box for manufacturing a battery according to the invention and to a method for producing a battery according to the invention.