Secondary Battery Cap Assembly Inversion Plate Safety Mechanism
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Solution Overview
Problem
Secondary batteries face safety risks due to potential internal pressure increases from over-charging, which can lead to explosions or fires if not adequately managed.
Innovation Solution
The design incorporates a cap assembly with a deformation inducing groove and a short-circuit member featuring an inversion plate that inverts to establish an electrical short circuit when internal pressure exceeds a threshold, cutting off current flow and preventing further charging or discharging, thereby ensuring safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the inversion plate is inverted to establish electrical short circuit when internal pressure exceeds threshold, then battery safety is improved by interrupting current flow, but contact resistance increases which may affect the reliability of the short circuit function
Solution Approach 1:
The groove is pre-formed in the cap plate at a position that will align with the inversion plate's inverted position. This preliminary structural preparation ensures that when the inversion plate inverts under high internal pressure, it immediately makes contact with the groove, establishing a low-contact-resistance electrical short circuit path without delay or instability.
Solution Approach 2:
The groove acts as an intermediary element between the inversion plate and the cap plate. It provides a dedicated contact interface that facilitates reliable electrical connection during the short circuit event, mediating the interaction between moving and stationary components to ensure consistent low contact resistance.
2Reliability
If the inversion plate is designed to invert freely to establish short circuit, then the safety response is improved, but the structural strength of the cap plate may be compromised
Solution Approach 1:
The cap plate is segmented by introducing a groove that creates a localized flexibility zone. This segmentation allows the cap plate to maintain overall structural strength while providing a specific region that can deform to accommodate the inversion plate's movement, thus preserving both strength and safety response effectiveness.
Solution Approach 2:
The groove creates a local quality change in the cap plate, making that specific region more flexible while the rest of the cap plate retains its full structural strength. This localized modification enables the inversion plate to invert and establish contact without compromising the overall integrity and strength of the cap plate structure.
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 solution effectively reduces contact resistance and facilitates a stable inversion of the inversion plate, ensuring the battery's safety by interrupting current flow and preventing potential explosions.
Implementation Method 1
an inversion plate (161) including an inversion section positioned in the short-circuit hole and bent toward the case, and an edge section at an edge of the inversion section and coupled to the cap plate
Implementation Method 2
the cap plate includes a deformation inducing groove adjacent to and spaced from the short-circuit hole
Implementation Method 3
The coupling region may be welded and coupled to the inversion plate
Data Source
Figure 1
Figure 2~3A
Figure 3B~5A
AI summary
A secondary battery includes a first electrode plate and a second electrode plate, a case accommodating the electrode plates, and a cap assembly to seal the case. The cap assembly has a short-circuit hole and a cap plate electrically connected to the first electrode plate. The battery also includes an inversion plate spaced from a short-circuit plate. The inversion plate is positioned in or over the short-circuit hole and bent toward the case. The short-circuit plate is electrically connected to the second electrode plate. When an internal pressure of the battery exceeds a value, the inversion plate moves to contact the short-circuit plate, which, in turn, breaks a fuse. A groove is included in the gap assembly adjacent the short-circuit plate. When the inversion plate moves under excessive pressure, an edge portion of the gap assembly deforms away from the short-circuit plate.