Battery Unit Buffer Structure for Cell Swelling Pressure Relief
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Solution Overview
Problem
Lithium-ion battery cells swell during charge and discharge cycles, leading to increased pressure that can cause lithium precipitation, electrode plate damage, and reduced battery performance and service life, due to the lack of effective pressure relief mechanisms.
Innovation Solution
A battery unit design incorporating a buffer with a packaging structure that accommodates swelling pressure by gradually opening to form a buffer space, preventing cell loosening and electrode plate damage, and maintaining a fully-filled state to prevent lithium precipitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the cell is tightly accommodated in the housing to prevent movement, then the battery structure stability is improved, but the cell swelling during use causes increased pressure that can damage the electrode plate and reduce service life
Solution Approach 1:
The buffer is pre-installed between the cell and the housing to provide cushioning before swelling occurs. The buffer absorbs the swelling pressure of the cell during charge and discharge cycles, preventing direct contact between the swollen cell and the housing, thereby avoiding damage to the electrode plate and extending service life while maintaining structural stability.
2Reliability
If gaps are left between the cell and housing to accommodate swelling, then the pressure relief is improved, but the cell winding structure may loosen causing lithium precipitation
Solution Approach 1:
The buffer acts as an intermediary substance between the cell and the housing. It provides a controlled interface that allows for pressure relief during swelling while maintaining sufficient contact pressure to prevent cell loosening and lithium precipitation. The buffer mediates between the conflicting requirements of pressure relief and structural stability.
3Object-generated harmful factors
If the buffer is made with strong packaging structure to maintain fully-filled state, then the prevention of lithium precipitation is improved, but the swelling pressure cannot be relieved effectively
Solution Approach 1:
The buffer's packaging strength parameter is specifically optimized to balance two conflicting requirements: it must be strong enough to maintain a fully-filled state and prevent cell loosening, yet weak enough to allow controlled opening when swelling pressure exceeds a certain threshold. This parameter optimization enables the buffer to prevent lithium precipitation under normal conditions while relieving excessive swelling pressure when needed.
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 buffer effectively relieves swelling pressure, prolongs battery service life, and prevents lithium precipitation by allowing the battery unit to maintain a fully-filled state, reducing the influence of swelling on the electrode plate and enhancing stability.
Implementation Method 1
a cell of a current battery may swell due to increase of temperature and using time of the cell during charge and discharge in use
Implementation Method 2
when pressure in the accommodating cavity exceeds packaging strength of the packaging structure, the packaging region is opened to form a buffer space that communicates with the accommodating cavity
Data Source
AI summary
This application discloses a battery unit. The battery unit includes a housing, at least one cell, and a buffer. The at least one cell is accommodated in the housing, the buffer is disposed corresponding to a side wall of the cell, and the buffer is provided with an accommodating cavity. A periphery of the accommodating cavity includes at least one packaging structure, the packaging structure includes at least one level of packaging region with a predetermined length. When pressure in the accommodating cavity exceeds packaging strength of the packaging structure, the packaging region is opened to form a buffer space that communicates with the accommodating cavity, reducing influence caused by swelling of the cell.