Flexible Membrane Compensator for Battery Cell Swelling
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Solution Overview
Problem
Conventional battery systems face issues due to swelling of battery cells during charging and discharging, leading to early failure and reduced energy density, necessitating a compensation system to manage the additional force and extend the lifetime of the battery system.
Innovation Solution
A battery system incorporating a flexible membrane compensator at the ends of battery cell stacks, filled with a fluid, which expands and contracts in response to pressure changes to exert a pressing force, equalizing tolerances and compensating for swelling, utilizing a fluid manifold for interconnected compensators and one-way valves to regulate pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If battery cells are stacked and squeezed during assembly, then mechanical integration and tolerance equalization are improved, but battery cell swelling during charging/discharging causes additional force that leads to early failure and reduced energy density
Solution Approach 1:
The compensator is pre-filled with fluid at a specific pressure before battery assembly. This preliminary pressurization ensures that when the battery cells are stacked and squeezed, the compensator is already in a state to counteract the mechanical forces and accommodate subsequent swelling during charging/discharging cycles.
Solution Approach 2:
The fluid-filled compensator acts as a cushioning element that absorbs and compensates for the additional forces generated by battery cell swelling during operation. The fluid pressure is specifically controlled to provide counteracting force that prevents mechanical failure while maintaining tolerance equalization.
2Quantity of substance
If battery cells are tightly stacked to increase energy density, then space utilization is improved, but swelling during charging/discharging creates overpressure leading to early failure
Solution Approach 1:
The fluid-filled compensator serves as an intermediary element between the tightly stacked battery cells and the external environment. It mediates the overpressure generated by cell swelling by absorbing the expansion forces through fluid compression, thereby protecting the battery stack while maintaining high energy density.
Solution Approach 2:
The compensator utilizes hydraulic principles by filling a confined space with fluid that can be pressurized to a specific level. This fluid pressure is controlled to counteract the swelling forces during charging/discharging, providing a mechanical counterbalance that prevents overpressure damage while allowing tight stacking for maximum energy density.
3Reliability
If compensator fluid pressure is increased to counteract swelling, then battery lifetime is extended, but overpressure may cause damage to battery cells
Solution Approach 1:
The compensator system carefully controls the fluid pressure parameter within a specific range. The pressure is increased enough to counteract swelling forces and extend battery lifetime, but maintained below the threshold that would cause damage to the battery cells. This precise parameter control resolves the contradiction between protective force and potential harm.
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 stabilizes the battery system by equalizing swelling and preventing overpressure, extending the battery's lifetime and maintaining stable operating conditions through hysteresis regulation, while also allowing for compact integration and retrofitting into existing systems.
Implementation Method 1
a flexible membrane (22) coupled to a membrane carrier (26) to define a variable volume (24) that is filled with a fluid. The flexible membrane (22) is configured to expand in response to the fluid pressure rising in the at least one compensator (20) and contract in response to the fluid pressure reducing in the at least one compensator (20)
Implementation Method 2
The flexible membrane (22) is configured to expand in response to the fluid pressure rising in the at least one compensator (20) and contract in response to the fluid pressure reducing in the at least one compensator (20)
Implementation Method 3
One among at least one compensator (20) is positioned at the end of the at least one battery cell stack (10) to exert a pressing force on the at least one battery cell stack (10)
Data Source
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AI summary
The present disclosure refers to a battery system (100) including at least one battery cell stack (10, 10') having a plurality of battery cells (12) accommodated in a compartment (16). At least one compensator (20) is located at an end (13) of a respective battery cell stack (10, 10') wherein the at least one compensator (20) includes a flexible membrane (22) coupled to a membrane carrier (26) to define a variable volume (24) that is filled with a fluid. The at least one compensator (20) is configured to expand in response to the fluid pressure rising in the flexible membrane (22) and contract in response to the fluid pressure reducing in the flexible membrane (22). One among at least one compensator (20) is positioned at the end (13) of the at least one battery cell stack (10) to exert a pressing force on the at least one battery cell stack (10).