Battery Pack Service Plug Gap Design for Electric Shock Prevention

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Solution Overview

Problem

Existing pouring structures for battery packs in electric vehicles do not adequately protect operators from high-voltage electric shock during emergency water pouring, as they lack effective mechanisms to prevent finger insertion into high-voltage components.

Innovation Solution

A pouring structure with a service plug having an electrically insulated structure and a closure member with a protrusion, forming a gap that prevents finger insertion, allowing for easy water pouring while ensuring operator safety by using a closure member fixed to the floor panel or battery pack, which can be opened without tools in emergency situations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If an inlet port is provided that can be easily opened without tools, then water can be poured quickly into the battery pack during emergency, but the operator may accidentally insert finger into the inlet port and touch high-voltage components causing electric shock

Engineering Contradiction:
Improveease of water pouringVSAvoidelectric shock risk
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a service plug as an intermediary component between the inlet port and the high-voltage components inside the battery pack. The service plug with electrically insulated structure serves as a mediator that allows water pouring while preventing direct contact with high-voltage components. The plug can be easily removed by hand during emergency but blocks access to internal components, thus resolving the contradiction between ease of operation and electric shock prevention.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent extracts the function of preventing finger insertion from the inlet port structure itself and implements it through a separate service plug component. By taking out the protective function into a dedicated removable plug, the system maintains easy access for water pouring while independently providing protection against accidental contact with high-voltage components.

Inventive Principle:
Principle #2Taking out (Extraction)

2Object-affected harmful factors

If the gap between service plug and inlet port is made small to prevent finger insertion, then operator safety is improved, but the service plug manipulation becomes more difficult

Engineering Contradiction:
Improveelectric shock protectionVSAvoidservice plug manipulation
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The patent applies local quality by creating a protrusion only at the specific location where the service plug interfaces with the inlet port closure member. This localized structural feature maintains a small gap precisely where needed for safety while not affecting other areas of the system. The protrusion is strategically placed to control the gap dimension without complicating the overall manipulation of the service plug.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The service plug is designed to be dynamically removable by hand during emergency situations, while the gap dimension is statically controlled by the protrusion structure. The system allows dynamic access when needed (plug removal) while maintaining static safety dimensions (gap size controlled by protrusion), thus resolving the contradiction between safety and ease of manipulation.

Inventive Principle:
Principle #15Dynamics

3Object-affected harmful factors

If a closure member with protrusion is used to maintain small gap, then safety is improved, but the device complexity increases

Engineering Contradiction:
Improvefinger insertion preventionVSAvoidclosure member structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The closure member incorporates a protrusion as a localized structural feature rather than a complete redesign of the entire closure mechanism. This local modification maintains the simplicity of the overall closure member while achieving the safety function of preventing finger insertion through the controlled gap dimension. The protrusion is a minimal added complexity that provides maximum safety benefit.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2624332B1Pouring structure for battery pack
Publication Date: 2015.09.09 MITSUBISHI MOTORS CORP
  • EP2624332B1 patent drawingFigure 1
  • EP2624332B1 patent drawingFigure 2
  • EP2624332B1 patent drawingFigure 3

AI summary

An inlet port (41) of a service plug cover (40) has an inner diameter smaller than the outer shape of a service plug (22) as viewed from above. The gap between the service plug (22) and the inner peripheral edge of the inlet port (41) of the service plug cover (40) is set so as to be smaller than a preset value (e.g., 9.5 mm) when the service plug cover (40) is fixed to a floor panel (11) with a battery pack (21) mounted on a vehicle body (10).