Cap Assembly Short-Circuit Mechanism for Battery Safety
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Solution Overview
Problem
Secondary batteries face safety concerns due to potential explosions or ignitions from overcurrent and internal pressure increases, which existing designs fail to adequately address, particularly in high-power applications.
Innovation Solution
The design incorporates a cap assembly with a short-circuit hole and reverse plates that induce a controlled short circuit when internal pressure exceeds a threshold, preventing explosions and allowing for potential reuse of components, thus enhancing safety and reducing material costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sealed cap assembly is used to prevent external contamination, then reliability is improved, but internal pressure buildup from overcurrent can cause explosions
Solution Approach 1:
The patent converts the harmful effect of internal pressure buildup into a beneficial safety mechanism. When overcurrent causes internal pressure to increase, the flexible membrane deforms and causes reverse plates to contact terminal portions, creating a controlled short circuit that prevents explosion. The harmful pressure buildup is thus transformed into a protective action that eliminates the danger.
Solution Approach 2:
The flexible membrane acts as an intermediary element between the internal pressure source and the reverse plates. It translates pressure changes into mechanical displacement, which then triggers the short-circuiting action. This intermediary mechanism allows the system to respond to pressure buildup in a controlled manner rather than allowing direct explosive failure.
2Reliability
If safety mechanisms are added to prevent explosions, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple functions into the cap assembly structure. The cap assembly simultaneously serves as a seal against external contamination, a pressure sensor (through the flexible membrane), and a switch actuator (through the reverse plates and terminal portions). This integration achieves explosion prevention without adding separate complex safety systems.
Solution Approach 2:
The reverse plates serve multiple functions: they act as electrical conductors, mechanical actuators, and safety switch triggers. The same structural elements that provide mechanical support also enable the safety short-circuiting function, reducing the need for additional dedicated safety components.
3Reliability
If protective structures are implemented to prevent overcurrent damage, then reliability is improved, but manufacturing cost increases
Solution Approach 1:
The patent enables recovery and reuse of battery components after safety activation. When the flexible membrane deforms and triggers the short circuit, the reverse plates are positioned to allow subsequent resetting or replacement without damaging the entire battery structure. This reduces waste and manufacturing costs by allowing component reuse.
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 prevents explosions and ignitions by inducing a controlled short circuit under high pressure, improving safety and minimizing damage to the secondary battery components.
Implementation Method 1
when an internal pressure of the case is higher than a predetermined pressure, the protruding portion of the second reverse plate contacts the first and second accommodating grooves of the first terminal portion
Data Source
AI summary
A secondary battery includes an electrode assembly including a first electrode plate, a second electrode plate and a separator, the separator being between the first and second electrode plates, a case accommodating the electrode assembly therein, the case having an opening, and a cap assembly sealing the opening of the case, the cap assembly having a short-circuit hole provided in one area thereof, a first reverse plate and a second reverse plate positioned on a top of the first reverse plate being provided in the short-circuit hole of the cap assembly.