Cylindrical Battery Bottom Vent Grooves to Suppress Deformation

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Solution Overview

Problem

Existing cylindrical batteries face challenges in suppressing deformation of the bottom while ensuring safety, particularly during abnormal conditions, as previous techniques fail to adequately address this issue.

Innovation Solution

The cylindrical battery design incorporates a bottom with a first groove forming a polygon and multiple second grooves extending from its vertices, which facilitate controlled rupture and gas discharge during abnormal conditions, thereby preventing bottom deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a cylindrical battery is charged at high current, then charging speed is improved, but heat generation increases causing safety issues

Engineering Contradiction:
Improvecharging speedVSAvoidheat generation
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The battery electrode is divided into multiple independent electrode segments along the axial direction, with each segment having its own current collector and being electrically isolated from others. This segmentation allows distributed current collection, reducing current density at any single location and thereby reducing heat generation during high-current charging while maintaining overall charging speed.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the battery are designed with different properties: the electrode segments have varying lengths and active material compositions optimized for their specific positions, and the current collectors are strategically placed to distribute current collection locally. This local optimization reduces hot spots and improves heat distribution during high-current operation.

Inventive Principle:
Principle #3Local quality

2Quantity of substance

If electrode active material amount is increased, then battery capacity is improved, but internal stress during charge-discharge increases causing performance degradation

Engineering Contradiction:
Improvebattery capacityVSAvoidinternal stress resistance
Core Design Contradiction:
Quantity of substanceVSStrength

Solution Approach 1:

The electrode is segmented into multiple sections along the axial direction, with each segment containing active material and being connected to current collectors. This segmentation reduces the continuous stress path during lithium ion insertion and extraction, preventing stress accumulation and propagation that would otherwise lead to electrode degradation and capacity fade.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The battery design incorporates flexible connections between electrode segments that allow for dynamic stress distribution during charge-discharge cycles. The segmented structure enables local deformation without affecting the entire electrode, maintaining structural integrity under varying stress conditions.

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If battery size is reduced for portability, then ease of operation is improved, but heat dissipation capability deteriorates

Engineering Contradiction:
ImproveportabilityVSAvoidheat dissipation
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The battery is divided into multiple electrode segments with independent current collectors, creating multiple heat generation zones that are spatially distributed. This segmentation improves heat dissipation by preventing heat concentration in a single location, allowing efficient heat management even in compact battery designs suitable for portable devices.

Inventive Principle:
Principle #1Segmentation

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 design effectively suppresses bottom deformation and enhances safety by allowing controlled venting of internal pressure, improving overall battery performance.

Implementation Method 1

the porous coating layer has a function of retaining the electrolyte solution

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

a positive electrode and a negative electrode which are alternately charged and discharged in accordance with a predetermined charging/discharging cycle

Methodology Applied
Scientific EffectElectrochemical reaction: Electrochemiluminescence

Data Source

PatentEP4421952B1Cylindrical battery
Publication Date: 2026.04.29 PANASONIC ENERGY CO LTD
  • EP4421952B1 patent drawingFigure 1
  • EP4421952B1 patent drawingFigure 2
  • EP4421952B1 patent drawingFigure 3

AI summary

Provided is a cylindrical battery that has improved safety and also suppresses deformation of a bottom part. According to one aspect of the present disclosure, a cylindrical battery comprises an electrode body, an electrolyte, an outer can that is a bottomed cylinder that houses the electrode body and the electrolyte, and a sealing body that closes an opening part of the outer can. A bottom part of the outer can has a first groove that forms a polygon and a plurality of second grooves that respectively extend from the plurality of vertices of the polygon toward the outside.