Rechargeable Battery CID Structure for Vibration Durability
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Solution Overview
Problem
Conventional current interrupt devices (CIDs) in rechargeable batteries face challenges in reducing resistance and ensuring durability during high current applications and vibrations, particularly in large square-shaped batteries for hybrid electric vehicles, due to their complex structure and high resistance, which can lead to increased temperature and safety concerns.
Innovation Solution
A simplified CID structure with a membrane, insulator, and fastening member that reduces electrical resistance and enhances durability by using a membrane with a flange and welding parts, supported by a middle plate and fastening rivets, and a bus bar connection for series configuration, allowing for efficient overcharge protection and improved mechanical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional CID with complex structure is used, then overcharge protection function is achieved, but electrical resistance increases and durability during vibration or impact deteriorates
Solution Approach 1:
The CID is divided into separate functional components: a membrane element for overcharge protection and a support structure for mechanical stability. The membrane is separated from the cap plate by an insulator, allowing each component to be optimized independently for its specific function while reducing overall structural complexity.
Solution Approach 2:
The membrane is extracted as a separate functional element from the conventional integrated CID structure. By removing the membrane from direct contact with the cap plate and positioning it on an insulator, the design eliminates unnecessary structural complexity while maintaining the overcharge protection function.
2Reliability
If a conventional CID with complex structure is used, then overcharge protection function is achieved, but electrical resistance increases causing temperature increase
Solution Approach 1:
The membrane is extracted and positioned on an insulator rather than being directly integrated into the cap plate structure. This separation reduces the number of contact interfaces and fastening elements, thereby reducing electrical resistance and preventing temperature increase during high current operation.
Solution Approach 2:
An insulator is introduced as an intermediary element between the cap plate and the membrane. This insulator serves as a mediator that provides both mechanical support and electrical isolation, reducing resistance at the connection interface while maintaining the overcharge protection function.
3Reliability
If a conventional CID is used, then overcharge protection is provided, but durability during vibration or impact deteriorates
Solution Approach 1:
The support structure provides localized reinforcement at specific positions where the membrane contacts the cap plate, rather than requiring a completely rigid structure. This localized support approach enhances durability during vibration and impact while maintaining the flexibility needed for the membrane to function properly.
Solution Approach 2:
The insulator acts as a cushioning element that absorbs and distributes mechanical stresses from vibration and impact before they reach the membrane. This prior cushioning protects the membrane from damage while maintaining its overcharge protection function.
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 reduces electrical resistance and enhances the durability of the CID during vibrations and impacts, ensuring safe and efficient operation by interrupting overcharge and providing a stable connection, while also serving as a vent to prevent explosions.
Implementation Method 1
A rechargeable battery may include a current interrupt device (CID) that interrupts current upon overcharging
Implementation Method 2
a first welding part that is convexly formed toward the first middle plate in the first flange to be electrically connected to the first middle plate
Implementation Method 3
a fastening member that fastens the cap plate and the first insulator
Data Source
AI summary
A rechargeable battery includes an electrode group in a case, the electrode group including a first electrode and a second electrode, a cap plate coupled to the case, an electrode terminal electrically connected to the first electrode, the electrode terminal being electrically insulated from the cap plate, and a current interrupt device (CID) electrically connected to the second electrode and the cap plate, the CID including a membrane on a first surface of the cap plate, the membrane being between and electrically connecting the second electrode and the cap plate, and the membrane being configured to interrupt the electrical connection when a voltage greater than a setting voltage is charged, a first insulator contacting the first surface of the cap plate and at least one surface of the membrane to support the membrane, and a fastening member connecting the cap plate and the first insulator.