Secondary battery

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Solution Overview

Problem

Secondary batteries have not achieved sufficient energy density per unit volume, necessitating improvements in their configuration to enhance performance.

Innovation Solution

The secondary battery design includes a power generation element with electrodes stacked and separated by a separator, featuring current collectors with bent parts that overlap and terminate at a middle point, optimizing the use of space within the battery can to increase energy density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If conventional electrode configurations are used with tabs disposed above and below the electrode group, then electrical connection is achieved, but non-device space volume increases and energy density per unit volume decreases

Engineering Contradiction:

Improveenergy density per unit volumeVSAvoidnon-device space volume

Core Design Contradiction:

Quantity of substanceVSVolume of stationary object

Solution Approach 1:

The current collectors are led out in a direction intersecting the stacking direction (horizontally rather than vertically), and bent parts are configured to overlap in the stacking direction. This dimensional reorganization allows current collectors to exit through the side faces of the battery can rather than requiring top/bottom access, reducing the volume occupied by non-device components and increasing energy density per unit volume.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Volume of stationary object

If current collectors are led out and bent to overlap adjacent bent parts, then device space volume is enhanced, but manufacturing complexity increases

Engineering Contradiction:

Improvedevice space volumeVSAvoidcurrent collector configuration complexity

Core Design Contradiction:

Volume of stationary objectVSDevice complexity

Solution Approach 1:

The current collectors are divided into distinct functional segments: a leading-out portion extending from the electrode, a bent portion forming the first bent part, and a tab portion. This segmentation allows each segment to be optimized independently for its specific function while simplifying the overall manufacturing process through modular assembly.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The bent portions of adjacent current collectors are configured to overlap and be in contact with each other, forming a compact curved arrangement. This curvature-based design allows the current collectors to terminate at a middle point on the end face rather than extending to the corners, optimizing space utilization and reducing device complexity.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Data Source

PatentUS12191529B2Secondary battery

Publication Date: 2025.01.07 MURATA MFG CO LTD

AI summary

A secondary battery includes a power generation element including a plurality of electrodes. The electrodes are stacked on each other in a stacking direction with a separator interposed therebetween. Each of the electrodes includes a current collector led out in a first direction intersecting the stacking direction. Each of a plurality of current collectors led out in the first direction includes an end part, and the end part includes a first bent part that is bent in a second direction intersecting the first direction. Each of a plurality of first bent parts overlaps and is in contact with an adjacent first bent part in the second direction. At least one of the first bent parts terminates at a middle point on an end face along the second direction of the power generation element.