Battery Pack Stacking with Viscous Filling Member Thickness Control

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Solution Overview

Problem

Variation in thickness of unit cells in battery packs makes it difficult to maintain constant intervals and height during stacking, leading to issues in connecting busbars and accommodating the stack in a case.

Innovation Solution

A method involving the use of a viscous filling member interposed between unit cells, with controlled thickness through measurement, arrangement, and pressurization steps to maintain consistent spacing and height, using the filling member's thickness, pressurization time, and force to adjust the stacking-direction thickness based on measured unit cell thicknesses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If unit cells with variation in thickness are stacked, then the battery pack can accommodate different manufacturing tolerances, but the intervals between stacked unit cells become non-constant and the stack height varies

Engineering Contradiction:

Improveaccommodation of manufacturing tolerancesVSAvoidstack height consistency

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

A viscous filling member is introduced as an intermediary substance between unit cells with varying thicknesses. This filling member compensates for thickness variations by being pressurized to reduce its thickness, thereby maintaining constant intervals between unit cells and ensuring uniform stack height despite manufacturing tolerances in the unit cells themselves.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The thickness of the viscous filling member is dynamically adjusted by applying pressurization force. By changing the pressure parameter during the stacking process, the filling member's thickness is reduced to compensate for variations in unit cell thickness, thereby maintaining constant stack height and intervals between cells.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If unit cells with variation in thickness are stacked, then manufacturing flexibility is improved, but the distance between centers of unit cells varies making busbar connection difficult

Engineering Contradiction:

Improvemanufacturing flexibilityVSAvoidbusbar connection accuracy

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The viscous filling member serves as a mediator that maintains constant center-to-center distances between unit cells. By pressurizing this filling member to achieve uniform thickness, the positional relationship between adjacent unit cells is standardized, enabling accurate busbar connections despite variations in individual unit cell thicknesses.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If the stack height varies due to unit cell thickness variation, then manufacturing adaptability is improved, but accommodation in a predetermined case becomes impossible

Engineering Contradiction:

Improvemanufacturing adaptabilityVSAvoidstack height

Core Design Contradiction:

Adaptability or versatilityVSLength of stationary object

Solution Approach 1:

The pressurization parameter is applied to the viscous filling member to control its thickness. By adjusting the pressure, the filling member's thickness is reduced to compensate for unit cell thickness variations, thereby maintaining a constant stack height that fits within predetermined cases while preserving manufacturing adaptability.

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This method ensures a constant height of the battery pack stack, facilitating easier busbar connection and accommodation within a predetermined space, regardless of unit cell thickness variations.

Implementation Method 1

arranging the viscous filling member between the unit cells adjacent in the stacking direction, and pressurizing the viscous filling member arranged between the unit cells in the stacking direction

Methodology Applied

Scientific EffectViscosity: Viscometer

Data Source

PatentUS10680219B2Battery pack production method

Publication Date: 2020.06.09 ENVISION AESC JAPAN LTD

AI summary

A battery pack production method is provided for producing a battery pack having several unit cells that are stacked with filling members interposed therebetween. The stacked unit cells are electrically connected. The battery pack production method includes measuring the thicknesses of the unit cells, arranging a filling member between adjacent ones the unit cells, and pressurizing the filling member to reduce a thickness of the filling member in the stacking-direction. In the battery pack production method, the thickness of the filling member is controlled based on the measured thicknesses of the unit cells after stacking according to at least one of: an amount of the elastic adhesives arranged; a length of time during which the elastic adhesives are pressurized; and a force pressurizing the elastic adhesives; and a distance between stacking-direction centers of two unit cells adjacent in the stacking direction is kept within a constant range.