Power Battery Cap Structure with Dual Protection Paths
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Solution Overview
Problem
Existing power battery cap structures fail to simultaneously protect against overcharge and nailing abuse due to contradictory requirements for resistance value, leading to inadequate safety measures.
Innovation Solution
A power battery cap structure with a first and second terminal, a cap assembly, and a resistance connecting the first terminal to the cap assembly, featuring first and second short circuit parts that form separate protection loops based on internal pressure thresholds, allowing for large resistance values during nailing abuse and high current paths during overcharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the resistance value between the positive terminal and cap sheet is made small to enable high current for melting connecting parts during overcharge, then the overcharge protection is improved, but the nailing abuse protection deteriorates because the current becomes too large and causes sparks that ignite electrolyte
Solution Approach 1:
The invention divides the protection function into two separate paths: Path 1 (through the resistance) for overcharge protection and Path 2 (through the short circuit part) for nailing abuse protection. This segmentation allows each path to be optimized independently - the resistance can be sized for controlled overcharge current while the short circuit part provides low-resistance path for nailing abuse without causing harmful sparks.
Solution Approach 2:
The invention makes the resistance dynamically effective only during overcharge conditions by designing the circuit such that the resistance is in series with the short circuit part during normal operation, but becomes the primary current path during overcharge when the short circuit part melts or opens. This dynamic behavior allows the resistance to limit current during overcharge while not interfering with nailing abuse protection.
2Object-affected harmful factors
If the resistance value between the positive terminal and cap sheet is made large to limit current during nailing abuse, then the nailing abuse protection is improved, but the overcharge protection deteriorates because insufficient current is generated to melt the connecting part
Solution Approach 1:
The protection system is segmented into two independent current paths: Path 1 through the resistance for overcharge protection and Path 2 through the short circuit part for nailing abuse protection. This allows the resistance to be optimized for overcharge current requirements without being constrained by nailing abuse current limitations, as the short circuit part handles nailing abuse independently.
Solution Approach 2:
The short circuit part acts as an intermediary element that provides a low-resistance path during nailing abuse, preventing the need for the resistance to simultaneously satisfy both overcharge and nailing abuse current requirements. The short circuit part mediates the current flow during nailing abuse, allowing the resistance to be optimized solely for overcharge protection.
3Device complexity
If a single resistance value is used for both overcharge and nailing abuse protection, then the device complexity is reduced, but the ability to simultaneously protect against both overcharge and nailing abuse deteriorates
Solution Approach 1:
The invention segments the protection function into two distinct current paths with different resistance characteristics. Path 1 uses a controlled resistance for overcharge protection, while Path 2 uses a low-resistance short circuit part for nailing abuse protection. This functional segmentation enables simultaneous protection against both failure modes without requiring complex multi-resistance configurations.
Solution Approach 2:
The cap structure is designed with multi-functionality, where the cap sheet and associated components serve dual purposes: providing structural support and electrical connection while also enabling both overcharge protection (through Path 1) and nailing abuse protection (through Path 2). This universal design achieves comprehensive protection without proportionally increasing device complexity.
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
This design enables separate protection loops for overcharge and nailing abuse, preventing battery fires and explosions by managing current effectively in both scenarios, thus enhancing safety.
Implementation Method 1
a resistance which electrically connects the first terminal with the cap assembly
Implementation Method 2
when an internal pressure of the power battery exceeds a predetermined threshold, the first short circuit part and the second short circuit part act and then form a first path and a second path between the first terminal and the second terminal
Implementation Method 3
a great current is generated in the loop to melt off the connecting part so as to cut off the main loop
Data Source
AI summary
A power battery cap structure and a power battery are provided. The power battery cap structure includes a first terminal, a second terminal and a cap assembly; the second terminal is electrically insulated from the cap assembly. The power battery cap structure further includes a resistance which electrically connects the first terminal with the cap assembly. The cap assembly includes a cap sheet, a first short circuit part and a second short circuit part; the first and second short circuit part are attached to the cap sheet, when internal pressure of the power battery exceeds predetermined threshold, the first and second short circuit part act and form a first path passing through the first terminal, the second short circuit part, the resistance and the second terminal, and a second path passing through the first terminal, the first and second short circuit part and the second terminal.