Battery Stack End Plate and Binding Bar Structure Against Cell Expansion

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Solution Overview

Problem

Conventional power supply devices with rectangular battery cells face deformation or damage due to large dimensional variations during charging/discharging or degradation, leading to excessive load on binding bars and end plates.

Innovation Solution

A power supply device configuration featuring end plates with fitting parts and stoppers, and binding bars with engagement blocks, where the engagement blocks are guided to the fitting parts and stopped by the stoppers to resist tensile forces, distributing stress as shear rather than bending, thereby preventing deformation or damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If binding bars and end plates are used to assemble battery cells, then the battery cells are held together and expansion is suppressed, but large force is applied to the binding bars and end plates causing deformation or damage

Engineering Contradiction:

Improvebattery stack assembly stabilityVSAvoidbinding bar and end plate strength

Core Design Contradiction:

Stability of the object's compositionVSStrength

Solution Approach 1:

The binding bar is segmented into a plate-shaped bar portion and engagement block portions, where the engagement blocks are disposed at both ends of the plate-shaped bar. This segmentation allows the tensile force to be transferred to the engagement blocks which abut the end plates, rather than creating bending moments in the entire binding bar structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of having the binding bar directly connect to the end plates in a conventional manner that creates bending stress, the invention inverts the force transmission path by having engagement blocks abut the end plates. The plate-shaped bar portion connects the engagement blocks, creating a configuration where tensile force is converted to compressive force on the end plates, eliminating bending moments.

Inventive Principle:

Principle #13The other way round (Inversion)

2Use of energy by moving object

If rectangular battery cells with high energy density are used, then energy density per volume or weight increases, but dimensional variation during charging/discharging increases causing large load on binding bars and end plates

Engineering Contradiction:

Improveenergy densityVSAvoidbinding bar and end plate strength

Core Design Contradiction:

Use of energy by moving objectVSStrength

Solution Approach 1:

The invention accommodates the dynamic dimensional changes of high energy density battery cells during charging and discharging cycles. The engagement blocks can move relative to the plate-shaped bar, allowing the binding bar structure to adapt to cell expansion and contraction without generating excessive bending forces on the end plates.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention changes the mechanical interaction parameters between the binding bar and end plates. By using engagement blocks that abut the end plates rather than direct rigid connection, the system changes from a bending-dominated load regime to a tensile/compressive load regime, better suited for accommodating cell dimensional variations.

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If conventional binding bar configuration is used, then assembly is simple, but deformation or damage occurs due to bending stress from tensile force

Engineering Contradiction:

Improveassembly simplicityVSAvoidbinding bar resistance to deformation

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The binding bar is divided into a plate-shaped bar portion and engagement block portions, with the engagement blocks disposed at both ends. This segmentation allows the engagement blocks to directly abut the end plates, transferring tensile force away from the plate-shaped bar and preventing bending deformation while maintaining assembly simplicity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The engagement blocks act as intermediaries between the plate-shaped bar and the end plates. They mediate the force transmission by abutting the end plates, converting the tensile force in the plate-shaped bar into compressive force on the end plates, thereby eliminating bending moments while maintaining structural integrity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS11901582B2Power supply device, vehicle equipped with power supply device, and power storage device

Publication Date: 2024.02.13 SANYO ELECTRIC CO LTD

AI summary

A power supply device disposes an end plate at each end of a battery stack in a stacked direction of the battery stack, and couples a binding bar to the end plate, so as to fix battery cells. The binding bar includes a plate-shaped bar that extends in the stacked direction of the battery stack, and an engagement block that is fixed to the plate-shaped bar and protrudes as a face opposing an outer peripheral face of the end plate. The End plate includes a fitting part to which the engagement block is guided, and a stopper. The fitting part is disposed on the outer peripheral face of the end plate. The stopper is disposed closer to the battery stack with respect to the fitting part, and abuts the engagement block.