Battery Pack Case Engagement to Prevent Impact Mispositioning

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Solution Overview

Problem

Existing battery packs face mispositioning issues between the upper-part case and the cell case, particularly when subjected to impacts like accidental drops, which can lead to adverse contact between the upper-part case and the control board.

Innovation Solution

The battery pack design incorporates engaging parts on the upper-part case and corresponding engaged parts on the cell case, which engage with each other to reduce the likelihood of mispositioning, even if the battery pack is dropped.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the upper-part case and cell case are designed without engaging parts, then the device complexity is reduced, but mispositioning occurs between the upper-part case and cell case under impact

Engineering Contradiction:
Improvestructure complexityVSAvoidpositioning accuracy
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The battery pack is divided into separate upper-part case and cell case components, each with dedicated engaging parts. This segmentation allows independent positioning features to be designed on each component, enabling precise engagement without complicating the overall structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Engaging parts are pre-designed and pre-positioned on both the upper-part case and cell case before assembly. These engaging parts protrude and extend in advance to guide and constrain the relative positioning of the two cases, preventing misalignment before impact occurs.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If engaging parts are added to prevent mispositioning, then the positioning accuracy is improved, but the device complexity increases

Engineering Contradiction:
Improvepositioning accuracyVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The engaging parts are integrated into the existing case structures rather than being separate components. The protruding engaging part on the upper-part case and the extending engaging part on the cell case are merged with the case bodies, achieving precise positioning without adding discrete parts or complex assembly steps.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The engaging parts serve multiple functions: they provide positioning guidance during assembly, maintain precise alignment during operation, and prevent mispositioning under impact conditions. This multi-functionality reduces the need for additional dedicated positioning mechanisms.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Volume of moving object

If the upper-part case is positioned close to the control board, then the device compactness is improved, but the harmful effect of adverse contact increases under impact

Engineering Contradiction:
Improvedevice compactnessVSAvoidcontact damage risk
Core Design Contradiction:
Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

The engaging parts create a preliminary constraint system that prevents the upper-part case from shifting or mispositioning before impact can occur. By establishing this preventive mechanism in advance, the design counteracts the potential harmful effect of adverse contact between the upper-part case and control board during impact events.

Inventive Principle:
Principle #9Preliminary anti-action

Data Source

PatentEP3799196B1Battery pack
Publication Date: 2025.06.04 MAKITA CORP
  • EP3799196B1 patent drawingFigure 1A
  • EP3799196B1 patent drawingFigure 1B
  • EP3799196B1 patent drawingFigure 1C

AI summary

Object To provide a technique in which the likelihood of mispositioning between an upper-part case and a cell case of a battery pack can be reduced. Solution A battery pack (2; 402; 602) includes an outer case (12; 412; 612), which comprises an upper-part case (14; 414) and a lower-part case (15; 415) fixed to the upper-part case (14; 414), and a cell case (80; 480; 780; 980), which is housed in the outer case (12; 412; 612). An engaging part (30) is provided on one of the upper-part case (14; 414) and the cell case (80; 480; 780; 980). An engaged part (110), with which the engaging part (30) engages, is provided on or in the other of the upper-part case (14; 414) and the cell case (80; 480; 780; 980).