Battery Terminal Plate Deformation for Current Breaking
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Solution Overview
Problem
Conventional battery packs with current breaking structures fail to effectively cut off current when internal pressure increases due to the rigidity of the bus bar, which prevents the battery case from freely swelling and disconnecting the current.
Innovation Solution
A battery pack design featuring a current collector and insulating member with a thin portion on the terminal plate that deforms outward to break the electric connection when internal pressure rises, allowing the bus bar to cover other portions and enabling the current breaking structure to function even with a bus bar connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a thick bus bar is used to connect adjacent secondary batteries, then the current carrying capacity is improved, but the flexibility of the connection is worsened, preventing the battery case from freely swelling when internal pressure rises
Solution Approach 1:
The connection structure is segmented into multiple functional zones: a rigid bus bar region for current conduction and a flexible terminal plate region with thin portions for pressure-responsive deformation. This segmentation allows the bus bar to maintain electrical connection while the terminal plate provides the necessary flexibility for swelling.
Solution Approach 2:
Different parts of the terminal plate have different thicknesses - thin portions that deform under pressure and thick portions that maintain structural integrity and electrical connection. This local quality differentiation enables the terminal plate to simultaneously provide mechanical flexibility and electrical conductivity.
2Reliability
If the bus bar is fixed in contact with the bottom wall, then the electrical connection is stable, but the current breaking function is lost when internal pressure increases
Solution Approach 1:
The terminal plate is designed with thin portions that can dynamically change their state from connected to disconnected based on internal pressure conditions. Under normal conditions, the thin portions maintain electrical connection; when pressure rises, they deform to break the connection, providing a dynamic response to changing conditions.
Solution Approach 2:
The thin portion of the terminal plate acts as an intermediary element between the rigid bus bar and the swelling battery case. It transmits the mechanical deformation from case swelling to electrical connection breaking, enabling the current breaking function while maintaining stable connection during normal operation.
3Reliability
If a current breaking structure is added to the secondary battery, then the safety function is improved, but the device complexity increases
Solution Approach 1:
The current breaking structure is merged with the terminal plate and bus bar connection system. The thin portions of the terminal plate serve dual functions: providing electrical connection during normal operation and breaking the connection when pressure rises. This merging eliminates the need for separate current breaking mechanisms.
Solution Approach 2:
The terminal plate's thin portions automatically respond to internal pressure changes by deforming and breaking the electrical connection without requiring external control systems. The structure serves itself by using the pressure-induced deformation to trigger the current breaking function, eliminating the need for additional sensors or control mechanisms.
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 battery pack effectively cuts off current and then releases gas through an explosion-proof valve, ensuring safe operation by prioritizing current disconnection before gas release.
Implementation Method 1
the thin portion of the first terminal plate is to be deformed outward when internal pressure of the battery rises, thereby breaking electric connection between the first terminal plate and the current collector
Implementation Method 2
This explosion-proof valve is designed to break in case the internal pressure exceeds a predetermined value, thereby releasing the internally accumulated gas to the outside
Data Source
AI summary
A secondary battery includes a cylindrical battery case, a positive and negative electrode body group, a top plate and a battery lid connected to first and second electrode bodies of the electrode body group respectively. The secondary battery further includes a current collector placed on an end of the electrode body group on the top plate side and connected to the first electrode body of the electrode body group and a spacer placed between the top plate and the current collector. The top plate is partly formed with a thin portion. The spacer is formed with through holes in positions corresponding to the thin portion. The portion of the current collector corresponding to the thin portion is in contact with the thin portion through the through hole. The thin portion is deformed when the internal pressure of the battery case rises, thereby breaking electric connection between the top plate and the current collector.