Insulated Fastening Structure for Battery Pack Electrical Isolation
Solution Overview
Problem
Existing battery pack fixation methods fail to prevent electrical short-circuits caused by conductive fluid substances, such as electrolyte mist, which can lead to dangerous voltage short-circuits between battery modules and installation substrates.
Innovation Solution
A battery pack configuration that includes a metallic fastening part with a male screw shaft and a nut or bolt, combined with an insulating member featuring an annular and plate-like insulating part to electrically isolate the fastening part from both the attachment member and the installation substrate, preventing contact with conductive substances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a metallic fastening member such as a screw or bolt is used to strongly fix two elements, then the fastening strength is improved, but electrical insulation between the elements cannot be ensured
Solution Approach 1:
An insulating member is introduced as an intermediary component between the metallic fastening member and the metallic attachment member. The insulating member includes an insulating collar that surrounds the fastening member and an insulating plate that contacts the attachment member, thereby preventing direct electrical contact while maintaining the fastening function.
Solution Approach 2:
The fastening structure combines different materials with complementary properties: metallic fastening members for strength, insulating materials (such as resin or plastic) for electrical insulation, and a composite structure that integrates both functions. The insulating member is made of non-conductive material that complements the metallic components.
2Reliability
If an insulating spacer with a shape larger than the outer diameter of the metal screw is used, then electrical insulation is improved, but the head part of the metal screw becomes exposed and insulation is compromised
Solution Approach 1:
The insulating member is divided into multiple functional parts: an insulating collar that surrounds the screw shaft and engages with the screw threads, and an insulating plate that provides additional insulation at the attachment member interface. This segmentation allows each part to perform its specific function effectively.
Solution Approach 2:
The insulating collar is designed to fit over and surround the metallic fastening member, creating a nested structure where the insulating component envelops the conductive component. This nesting ensures that the screw shaft is completely covered for electrical insulation while maintaining structural integrity.
3Reliability
If the insulating member completely covers the fastening part, then electrical insulation is improved, but the attachment member cannot be properly fastened
Solution Approach 1:
The insulating member provides electrical insulation at critical locations where electrical contact would occur, such as around the screw shaft and at the attachment member interface, while leaving other areas open for mechanical fastening functions. The insulation is applied locally where needed rather than uniformly throughout.
Data Source
AI summary
Battery pack includes battery module, metallic installation substrate, metallic attachment member disposed between battery module and installation substrate, metallic fastening part, and insulating member for electrically insulating fastening part and attachment member, and attachment member and installation substrate, from each other, respectively. Insulating member includes annular insulating part having an inner-diameter hole allowing passing through of a male screw shaft portion of fastening part, and electrically insulating between attachment member and an entire surface of an outer periphery of the male screw shaft portion of the fastening part, and between attachment member and an entire surface of an outer periphery of the larger-diameter portion of fastening part; and plate-like insulating part having a corresponding inner-diameter hole which corresponds to the inner-diameter hole of annular insulating part and allows passing through of the male screw shaft portion of fastening part, and electrically insulating between attachment member and installation substrate.