Battery Cell Edge Buffers for Underfloor Load Rigidity

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Solution Overview

Problem

Existing power storage devices face challenges in maintaining high rigidity against loads input from above, particularly when positioned below a vehicle floor panel and subjected to loads from the vehicle compartment.

Innovation Solution

The power storage device incorporates a design with buffer portions on the cells' upper surface edges, a plate-shaped portion covering these buffer portions, and optional elastic members or spacers to enhance rigidity, allowing load transmission through rigid edges and distributed support.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the power storage device is disposed below the floor panel to achieve higher energy density, then the energy density is improved, but the rigidity against loads from above deteriorates

Engineering Contradiction:

Improveenergy densityVSAvoidrigidity against loads from above

Core Design Contradiction:

Use of energy by moving objectVSStrength

Solution Approach 1:

The upper surface of each cell is divided into multiple buffer portions that are spaced apart from each other. This segmentation allows the load to be distributed across multiple discrete support points rather than concentrating stress on a continuous surface, thereby maintaining rigidity while preserving the compact design for high energy density.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Buffer portions are specifically positioned at the end edges of the cells where structural support is most needed. This local reinforcement strategy provides targeted rigidity enhancement at critical load-bearing locations without adding unnecessary structure across the entire cell surface, thus maintaining high energy density.

Inventive Principle:

Principle #3Local quality

2Strength

If buffer portions are provided at the end edges of cells to increase rigidity, then the rigidity is improved, but the device complexity increases

Engineering Contradiction:

ImproverigidityVSAvoidstructure complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The buffer portions are formed integrally with the cell cases through bending, merging the buffer structure with the existing cell housing. This integration eliminates the need for separate buffer components and reduces assembly steps, thereby increasing rigidity without proportionally increasing device complexity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

Instead of adding separate buffer components on top of the cells, the buffer portions are formed by bending the cell cases themselves outward. This inverted approach uses the existing cell structure to provide the buffering function, reducing overall structural complexity while achieving the desired rigidity enhancement.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS20250329856A1Power storage device

Publication Date: 2025.10.23 TOYOTA JIDOSHA KK

AI summary

In a power storage device, a plurality of cells are arranged in a first direction. A plurality of buffer portions are disposed on the plurality of cells. Each of the plurality of cells includes an upper surface portion facing upward. The upper surface portion includes a first end edge and a second end edge. The first end edge and the second end edge extend along a second direction, the second direction being a direction along the horizontal direction and orthogonal to the first direction. The plurality of buffer portions are spaced apart from each other on the upper surface portions of the plurality of cells, and at least one of the plurality of buffer portions is provided at at least one of the first end edge and the second end edge of each of the plurality of cells.