Cylindrical Battery Cap Assembly With Built-In BMS Moisture Sealing
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Solution Overview
Problem
Cylindrical lithium batteries lack a built-in BMS protection board and a corresponding sealing waterproof structure, allowing external moisture to enter and cause reduced capacity and increased internal resistance.
Innovation Solution
A cylindrical lithium battery cap sealing structure with a built-in BMS board, featuring a steel housing, plastic bracket with a sealing adhesive groove, and a cap mechanism that includes a positive aluminum plate, mainboard, negative hardware ring, and positive plastic cover, all of which are circular and annular to enhance sealing and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a BMS protection board is added to the lithium battery, then the safety and performance monitoring of the battery is improved, but the device complexity and structural design difficulty increase
Solution Approach 1:
The BMS protection board is integrated into the cap assembly structure, merging the protection board mounting function with the existing cap components. The plastic bracket is designed to simultaneously hold the protection board and provide sealing, eliminating the need for separate mounting structures and reducing overall device complexity despite adding protection functionality.
Solution Approach 2:
The cap assembly is designed to serve multiple functions: it provides the traditional cap sealing function, houses the BMS protection board, provides electrical connections through the aluminum plate, and maintains moisture barrier properties. This multi-functional design avoids adding separate components for each function, thereby managing complexity while improving reliability.
2Reliability
If a sealing waterproof structure is designed for the BMS protection board, then moisture resistance and battery performance stability are improved, but the manufacturing process complexity increases
Solution Approach 1:
A sealing ring made of flexible material is used to create the waterproof seal around the protection board mounting area. The flexible nature of the sealing ring allows it to conform to slight variations in assembly, providing reliable sealing without requiring precision machining or complex sealing structures, thus maintaining ease of manufacture while achieving moisture resistance.
Solution Approach 2:
The cap assembly uses composite material construction, combining metal (steel housing, aluminum plate), plastic (bracket, cap body), and elastomeric materials (sealing ring). This composite approach allows each material to perform its optimal function - metal for structural strength, plastic for insulation and mounting, and elastomer for sealing - while being manufacturable using standard processes for each material type.
3Reliability
If the cap structure is redesigned to include the BMS board and sealing structure, then the sealing performance is improved, but the ease of assembly and installation decreases
Solution Approach 1:
The cap assembly is segmented into distinct components: the cap body, plastic bracket, sealing ring, aluminum plate, and protection board. This segmentation allows each component to be manufactured and prepared separately, then assembled in a logical sequence. The bracket serves as a intermediate structure that simplifies the assembly of the protection board and sealing components onto the cap body.
Solution Approach 2:
The sealing ring is pre-installed onto the cap body before the protection board assembly is attached. This preliminary action ensures the sealing structure is in place before final assembly, allowing the sealing surface to be prepared and positioned correctly in advance, which simplifies the final assembly step and maintains ease of operation despite the increased complexity of the sealed structure.
Data Source
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AI summary
Disclosed is a cylindrical lithium battery cap sealing structure with a built-in BMS board, including a steel housing, wherein an outer surface of a side of the steel housing is fixedly connected to a bottom housing, and a top surface of the bottom housing is fixedly provided with a battery roll core adapted to the steel housing; and also including: a cap mechanism, wherein an outer surface of a side of the cap mechanism is fixedly connected to a connecting housing, and an outer surface of a side of the connecting housing is integrally connected to an outer surface of a side of the steel housing. The mainboard, negative hardware ring, and positive aluminum plate in the cylindrical lithium battery cap sealing structure with a built-in BMS board are all circular, whose structural feature is conducive to sealing. A plastic bracket is annular and has a sealing adhesive groove, when matched with the steel housing, a complete set of annular structures is formed, which will greatly improve the sealing of the storage battery, meanwhile, enhance the monitoring and control of the lithium battery, improve the performance and safety of the lithium battery. In addition, the invention features a simple structure, easy installation, and greater convenience.