Battery Cell Assembly Expansion Opening Parts Safety
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Solution Overview
Problem
Conventional battery cell assemblies face safety risks due to swelling phenomena during abnormal operations, leading to potential explosions and fires, as existing safety systems may malfunction and fail to effectively interrupt electrical connections when outermost battery cells swell, and there is a need for a structure that enhances safety and operational reliability.
Innovation Solution
A battery cell assembly design where expansion opening parts are formed on the surfaces of cell housing members to allow expansion forces to rupture the electrical connections between adjacent cells, thereby increasing the force required to break the connection and ensuring successful cut-off during abnormal operations, enhancing safety and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional safety systems (PTC element, BMS, fuse) are used to protect battery cells from overcharge, overdischarge, or overcurrent, then battery protection is provided, but the safety systems may malfunction and fail to interrupt electrical connections when outermost battery cells swell
Solution Approach 1:
The patent extracts the safety function from the electrical connection system by creating a physical separation mechanism. When battery cells swell, the expansion opening parts allow the cells to expand outward while the electrical connection is automatically interrupted through mechanical separation, removing the dependency on electronic safety systems that may malfunction.
Solution Approach 2:
The cell housing member acts as an intermediary structure between the battery cells and the external environment. It includes expansion opening parts that mediate the swelling phenomenon by providing a controlled path for expansion while simultaneously serving as a mechanical interrupter for electrical connections when swelling occurs.
2Object-affected harmful factors
If battery cells are tightly sealed in cell housing members to prevent gas leakage, then containment is improved, but the swelling phenomenon accelerates electrolyte decomposition and causes high pressure leading to explosion
Solution Approach 1:
The cell housing member is designed with expansion opening parts that anticipate the swelling phenomenon before it becomes dangerous. These opening parts are positioned and sized to allow controlled expansion of battery cells, preventing the buildup of excessive internal pressure that would lead to explosion while still containing the cells during normal operation.
3Reliability
If outermost battery cells are allowed to swell freely, then safety systems can detect the abnormal operation, but it is difficult to exhibit the desired cut-off effect because the expansion force is not concentrated
Solution Approach 1:
The cell housing member features expansion opening parts with specific local geometric properties that concentrate the expansion force of swelling battery cells onto specific regions. This local concentration of force ensures that when abnormal operation occurs, the mechanical interrupter effectively breaks the electrical connection, achieving rapid and reliable cut-off.
4Volume of moving object
If the battery module structure is made compact to reduce size and weight, then integration is improved, but the space for expansion is limited increasing the risk of explosion
Solution Approach 1:
The expansion opening parts are designed to utilize the radial dimension for cell expansion while maintaining a compact overall module size. This allows battery cells to expand in the radial direction through the opening parts without requiring additional axial or lateral space, thus preventing explosion risk while maintaining compact integration.
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 design effectively cuts off electrical connections between battery cells, achieving higher safety and operational reliability by concentrating expansion forces on the expansion opening parts, leading to a more rapid and effective cut-off effect compared to conventional assemblies.
Implementation Method 1
concentrating expansion forces on the expansion opening parts, leading to a more rapid and effective cut-off effect
Data Source
AI summary
Disclosed herein is a battery cell assembly including a plurality of battery cells stacked while being electrically connected to each other, wherein one or more of the battery cells are mounted in each cell housing member in a state in which opposite sides of the battery cells are surrounded by each cell housing member excluding electrode terminals of the battery cells, an expansion opening part, through which a portion of a main body of each of the battery cells is exposed outward when the battery cells expand, is formed at one surface or opposite surfaces of each of the at least two cell housing members and the battery cells are stacked such that the at least two expansion opening parts face each other.