Fluid Membrane Compensator for Battery Cell Swelling Control
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Solution Overview
Problem
Battery cells experience swelling during their lifetime due to charging and discharging, leading to increased force on the cells and reduced energy density, which can cause early failure and affect the overall performance of the battery system.
Innovation Solution
A battery system with compensators, each comprising a flexible membrane coupled to a membrane carrier, which expands and contracts in response to fluid pressure changes to exert a pressing force on the battery cell stack, equalizing tolerances and compensating for swelling, using a fluid manifold for interconnected compensators to distribute pressure evenly across multiple stacks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If battery cells are squeezed together in a compact arrangement, then energy density is improved, but swelling during charging/discharging causes increased force on cells leading to early failure
Solution Approach 1:
The battery system is divided into modular compartments, each containing a stack of battery cells. This segmentation allows independent management of swelling compensation for each module, enabling the system to maintain high density while accommodating cell expansion through localized compensator mechanisms.
Solution Approach 2:
A compensator mechanism acts as an intermediary between the battery cells and the compartment walls. This compensator absorbs the swelling forces generated by battery cells during charging and discharging, preventing these forces from being transmitted to the cell structures and thereby extending cell lifetime while maintaining compact arrangement.
2Stability of the object's composition
If battery cells are accommodated in a fixed compartment, then structural stability is improved, but swelling causes increased force on cells reducing energy density
Solution Approach 1:
The compensator mechanism introduces dynamic adaptability to the otherwise fixed compartment structure. The compensator can dynamically adjust its compression force on the battery cells based on their swelling state, maintaining optimal contact pressure for electrical connection while accommodating volume changes, thus preserving both structural stability and energy density.
Solution Approach 2:
The system changes the pressure parameter applied to battery cells through the compensator mechanism. By dynamically adjusting the compression force to match the swelling state of cells, the system maintains stable electrical connections and structural integrity while accommodating volume changes that would otherwise reduce energy density or cause failure.
3Reliability
If compensators are used to compensate for swelling, then battery cell lifetime is extended, but system complexity increases
Solution Approach 1:
The compensator mechanism is integrated with the existing compartment structure and battery management system. By merging the swelling compensation function into the existing modular compartment design and utilizing the battery management system for monitoring and control, the patent extends cell lifetime while minimizing the increase in overall system complexity.
Solution Approach 2:
The compensator mechanism is designed to automatically respond to battery cell swelling without requiring external intervention. The system self-regulates the compression force based on the swelling state of the cells, extending their lifetime through autonomous operation and reducing the complexity of external control systems.
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 solution effectively extends the lifetime of battery cells by equalizing tolerances and compensating for swelling, maintaining stable operating conditions and preventing overpressure, thereby improving the overall performance and efficiency of the battery system.
Implementation Method 1
The flexible membrane is configured to expand in response to a fluid pressure rising in the corresponding compensator and to contract in response to the fluid pressure reducing in the corresponding compensator
Implementation Method 2
One compensator from among the at least one compensator is positioned at the end of the at least one battery cell stack to exert a pressing force on the at least one battery cell stack
Data Source
AI summary
A battery system includes: a battery cell stack including a plurality of battery cells accommodated in a compartment; and a compensator at an end of the battery cell stack to exert a pressing force on the battery cell stack. The compensator includes a flexible membrane coupled to a membrane carrier to define a variable volume that is configured to be filled with a fluid. The flexible membrane is configured to expand in response to a fluid pressure rising in the compensator and contract in response to the fluid pressure reducing in the compensator.