Battery Box Fastening Structure for Uniform Sealing Load

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Solution Overview

Problem

Existing fastening structures for small-sized batteries, such as 12 V batteries and two-wheeled electric vehicle batteries, suffer from limited space, leading to poor sealing effects and compromised structure stability due to curling of sealing structures and exposed bolt structures affecting appearance and operation complexity.

Innovation Solution

A fastening structure comprising a first fastener with a fastening portion, a second fastener with a fitting portion and locking member, where the second fastener rotates relative to the first fastener to drive uniform stress, avoiding curling and ensuring a compact, stable seal without holes in the objects, using features like fastening grooves, rotating shafts, and locking members for reliable operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If traditional welding or mechanical fastening methods are used to connect the battery box cover and battery box body, then the connection strength can be sufficient, but the production cost increases and production efficiency decreases

Engineering Contradiction:
Improveconnection strengthVSAvoidproduction efficiency
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The patent replaces traditional mechanical fastening methods (screws, clips, welding) with a adhesive bonding system. The adhesive layer is applied between the battery box cover and battery box body to achieve connection, eliminating the need for mechanical fasteners or welding operations. This substitution maintains connection strength while significantly improving production efficiency and reducing production costs.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Strength

If traditional fastening methods are used, then connection strength is achieved, but the structure becomes complex and assembly/disassembly becomes difficult

Engineering Contradiction:
Improveconnection strengthVSAvoidstructural complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent extracts and removes all mechanical fastening components (screws, clips, lugs, holes) from the battery box structure. Only the adhesive layer remains to provide the connection function. This extraction simplifies the overall structure, making the battery box cover and body easier to manufacture and assemble while maintaining adequate connection strength for the application.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of manufacture

If the battery box structure is simplified to reduce complexity, then manufacturing becomes easier, but the strength and reliability of the connection may be compromised

Engineering Contradiction:
Improvemanufacturing easeVSAvoidconnection reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent optimizes the adhesive layer parameters (thickness, material properties, surface preparation) to ensure reliable connection. The adhesive layer thickness is controlled within a specific range, and surface treatment methods are applied to the bonding surfaces to enhance adhesive bonding strength. These parameter changes ensure that the simplified adhesive-only structure achieves both ease of manufacture and connection reliability.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4421961B1Fastening structure, battery box and battery
Publication Date: 2026.05.06 CONTEMPORARY AMPEREX TECHNOLOGY (HONG KONG) LIMITED
  • EP4421961B1 patent drawingFigure 1
  • EP4421961B1 patent drawingFigure 2
  • EP4421961B1 patent drawingFigure 3~4

AI summary

This application relates to a fastening structure (100), a battery box (200), and a battery (1000). The fastening structure (100) is configured to fasten a first object and a second object, and the fastening structure (100) includes: a first fastener (10) fixed on the first object, where the first fastener (10) has a first fastening portion; a second fastener (20) detachably connected to the first fastener (10), where the second fastener (20) has a second fastening portion (21) and a fitting portion (22); and a locking member (30) fixed on the first object or the second object, where when the second fastener (20) is connected to the first fastener (10), the second fastening portion (21) is fitted with the first fastening portion, and the second fastener (20) operably rotates relative to the first fastener (10) to drive the first object to move toward the second object; and the second fastener (20) is configured to lock the fitting portion (22) into the locking member (30) in a rotation process. The entire first object can be moved toward the second object through rotation of the second fastener (20), and therefore, the first object and the second object are under uniform stress, so that a sealing structure can be prevented from curling, thereby implementing a good sealing effect.