Floating Contact Plate for Battery Pack Electrical Connection

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Solution Overview

Problem

Hand-held electrical devices face challenges in securely and easily accommodating battery packs with a large number of cells due to increased weight and alignment issues during insertion, leading to problematic contact and potential mechanical damage.

Innovation Solution

A battery compartment design featuring a floating contact plate that compensates for positioning inaccuracies, swivel locking bolts for secure retention, and a centering element for precise alignment, along with guide elements and recesses for easy insertion and floating mounting, ensures secure and vibration-reduced contact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the battery pack accommodates more cells to provide higher voltages and greater power, then the power output is improved, but the weight increases making insertion and contact problematic

Engineering Contradiction:
Improvepower outputVSAvoidbattery pack weight
Core Design Contradiction:
PowerVSWeight of moving object

Solution Approach 1:

The contact plate is designed to be movable relative to the battery compartment bottom, allowing it to dynamically adjust its position to compensate for variations in battery pack weight and insertion depth, ensuring reliable electrical contact regardless of battery pack size

Inventive Principle:
Principle #15Dynamics

2Quantity of substance

If the battery pack is made larger to accommodate more cells, then the power capacity is improved, but the ease of operation during insertion deteriorates

Engineering Contradiction:
Improvenumber of cellsVSAvoidinsertion ease
Core Design Contradiction:
Quantity of substanceVSEase of operation

Solution Approach 1:

The floating contact plate design provides a cushioning effect that absorbs insertion inaccuracies and positioning variations, allowing larger battery packs to be inserted easily without requiring precise alignment while ensuring reliable contact is established

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If rigid contact elements are used to ensure stable electrical contact, then the contact reliability is improved, but the risk of mechanical damage from positioning inaccuracies increases

Engineering Contradiction:
Improveelectrical contact reliabilityVSAvoidmechanical damage risk
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The contact plate is designed to be movable relative to the battery compartment bottom, allowing it to dynamically adjust its position to compensate for variations in battery pack weight and insertion depth, ensuring reliable electrical contact regardless of battery pack size

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The floating contact plate design provides a cushioning effect that absorbs insertion inaccuracies and positioning variations, allowing larger battery packs to be inserted easily without requiring precise alignment while ensuring reliable contact is established

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

4Stability of the object's composition

If the contact plate is fixed rigidly to prevent movement, then the contact stability is improved, but the ability to compensate for positioning inaccuracies is lost

Engineering Contradiction:
Improvecontact plate stabilityVSAvoidpositioning accuracy compensation
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The contact plate is designed to be movable relative to the battery compartment bottom, allowing it to dynamically adjust its position to compensate for variations in battery pack weight and insertion depth, ensuring reliable electrical contact regardless of battery pack size

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2223779B1Portable, hand-held electric device with a battery pack
Publication Date: 2016.01.27 ANDREAS STIHL AG & CO KG
  • EP2223779B1 patent drawingFigure 1~2
  • EP2223779B1 patent drawingFigure 3~4
  • EP2223779B1 patent drawingFigure 5~6

AI summary

The invention relates to a handheld power tool, such as a hedge trimmer or chainsaw, with a housing (2) in which a battery compartment (31) is provided to accommodate a battery pack (1). The battery compartment (31) has guide elements (33) extending in the insertion direction (32), which interact with guide sections (17) of the battery pack (1). An electrical connection head (4) is formed on the housing (2) of the battery pack (1), to which contact elements (51, 51a) located in the battery compartment (31) are assigned. In a predetermined insertion position of the battery pack (1) in the compartment (31), the contact elements (51, 51a) make electrical contact with the connection head (4). To ensure reliable contact even with large, heavy battery packs, the contact elements (51, 51a) are arranged on a contact plate (50) in the battery compartment (31), with the contact plate (50) being mounted in a floating manner in the battery compartment (31).