Battery Module Balancing via Common Oxygen Gas Space
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Solution Overview
Problem
Nickel metal hydride (NiMH) batteries face issues with uneven electrolyte distribution due to uneven charging, leading to increased internal resistance and reduced lifetime, especially when multiple cells are connected, as they are not 100% identical, causing some cells to heat up faster and lose electrolyte unevenly, affecting the entire battery pack's performance.
Innovation Solution
A method involving connecting the gas spaces of battery modules to form a common gas space and adding oxygen or a gas mixture to balance internal resistances by determining the necessary amount based on data from measuring units, ensuring the difference in internal resistances between modules is within predetermined thresholds, using a control unit to manage the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple battery cells are connected to increase capacity, then the energy capacity of the battery pack is improved, but the internal resistance becomes uneven due to manufacturing variations and heating effects
Solution Approach 1:
The patent connects the gas spaces of multiple battery modules to form a common gas space, allowing electrolyte to be redistributed across all modules. This merging of gas spaces enables the electrolyte to flow freely between modules, compensating for uneven electrolyte levels caused by manufacturing variations and heating effects, thereby maintaining uniform internal resistance across all cells while preserving the increased energy capacity from having multiple cells.
Solution Approach 2:
The patent changes the physical state and distribution parameters of the electrolyte by creating a common gas space that allows electrolyte level equalization. This parameter change enables the electrolyte to redistribute itself based on pressure and concentration gradients, automatically compensating for variations in electrolyte consumption across different cells and maintaining uniform operational parameters throughout the battery pack.
2Duration of action of stationary object
If oxygen is added to balance internal resistance, then the lifetime of the battery pack is extended, but the complexity of the battery system increases due to gas management requirements
Solution Approach 1:
The patent merges the gas spaces of multiple battery modules into a single common gas space, which simplifies gas management by eliminating the need for individual gas control systems for each module. Oxygen can be introduced into the common gas space and will automatically distribute to all modules through the connected gas pathways, extending battery lifetime through improved electrolyte balance without requiring complex individual gas management for each cell or module.
Solution Approach 2:
The common gas space serves multiple functions simultaneously: it allows oxygen distribution to all modules, enables electrolyte level equalization, provides pressure balancing, and facilitates heat management. This multi-functionality reduces the need for separate systems for each function, thereby extending battery lifetime while minimizing the increase in system complexity.
3Ease of manufacture
If battery modules operate independently, then the manufacturing and assembly process is simplified, but the electrolyte distribution becomes uneven leading to reduced performance
Solution Approach 1:
The patent merges the gas spaces of independently manufactured modules into a common gas space after assembly, allowing the modules to retain their manufacturing independence while achieving operational interconnection. This approach maintains the ease of manufacture and assembly by allowing modular construction, but improves battery performance by enabling electrolyte redistribution across all modules through the connected gas space, eliminating uneven electrolyte distribution.
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 improves the operational efficiency and extends the lifetime of the battery pack by maintaining balanced electrolyte levels and reducing internal resistance variations, thereby enhancing the battery's overall performance and longevity.
Implementation Method 1
the gas spaces of the battery modules are connected to each other to form a common gas space... allowing gas to migrate between the electrodes
Implementation Method 2
During charge and discharge the electrodes interact with each other through the alkaline electrolyte as hydrogen is transported in the form of water molecules between the electrodes
Data Source
AI summary
The present invention relates to a method for improving the operational efficiency of a battery pack (100) comprising at least two battery modules (10, 10′, 10″), wherein each battery pack is configured to have a common gas space (29). The method comprises the steps of: obtaining data (101) on the battery modules (10, 10′, 10″), wherein the data relates to the number of battery cells per battery module, the number of battery modules, the temperature of each battery module and the energy capacity of the battery modules; obtaining (102) an indication of the internal resistance (Ri1, Ri2, Ri3) for the battery modules; determining (104), in case a difference in indication parameters between any of the battery modules exceeds a first threshold value, a filling amount of oxygen to be filled into the battery pack; and initiating (107) filling of the battery pack based on the determined filling amount of oxygen.