Battery Pack Connection Elements for Heat Dissipation

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Solution Overview

Problem

Existing battery packs face challenges in maintaining reliable electrical connections and adequate heat dissipation during assembly and operation, particularly with lithium-ion cells, which can lead to uncontrolled heat generation and potential explosions due to inhomogeneities and high current flows.

Innovation Solution

A battery pack design featuring connection structures with adapted cross-sections to manage current flow and decouple faulty cells, using holding structures for secure positioning and ventilation, and employing connection elements that limit current to prevent overheating, along with a method for manufacturing that ensures even current distribution and mechanical protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If spot welding or soldering is used to attach connection structures to battery cells, then reliable electrical connection is achieved, but very high local heat effects are generated on the individual cells

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidlocal heat effects on cells
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The connection structure is divided into multiple connection elements, each with an adapted cross-section, distributed across multiple battery cells. This segmentation allows the current to be distributed across multiple connection points rather than concentrated at a single spot welding location, reducing local heat effects while maintaining reliable electrical connection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each connection element has a specifically adapted cross-section designed for its particular battery cell connection point. This local optimization ensures that each connection element can handle the current density appropriately at its specific location, preventing overheating while maintaining reliable connection across all cells.

Inventive Principle:
Principle #3Local quality

2Productivity

If battery cells are arranged closely to maximize space utilization, then productivity and space efficiency are improved, but adequate ventilation and heat dissipation are compromised

Engineering Contradiction:
Improvespace utilization efficiencyVSAvoidheat dissipation capability
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The connection elements serve multiple functions: they provide electrical connection between the connection structure and battery cells, act as current distributors to ensure even current flow across all cells, and function as thermal management components by being positioned to facilitate heat dissipation from each cell connection point. This multi-functionality allows close cell arrangement while maintaining heat dissipation capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Power

If connection elements with large cross-section are used to handle high currents, then current carrying capacity is improved, but heat generation and risk of uncontrolled heat development increase

Engineering Contradiction:
Improvecurrent carrying capacityVSAvoidheat generation in connection elements
Core Design Contradiction:
PowerVSTemperature

Solution Approach 1:

The total current carrying requirement is segmented across multiple connection elements rather than using a single large cross-section element. Each connection element has a cross-section adapted to handle a portion of the total current, which reduces the heat generation per element while collectively maintaining the required current carrying capacity for the entire battery pack.

Inventive Principle:
Principle #1Segmentation

4Reliability

If individual battery cells are allowed to operate independently to detect failures, then safety and reliability are improved, but the complexity of the connection structure and current distribution increases

Engineering Contradiction:
Improvefailure detection and isolation capabilityVSAvoidconnection structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The connection structure is segmented into individual connection elements, each providing an independent electrical connection path to each battery cell. This segmentation enables individual cell monitoring and failure isolation without requiring complex additional circuitry - each connection element can be individually monitored and disconnected if its associated cell fails, maintaining system reliability while keeping the connection structure relatively simple.

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

The design ensures reliable electrical connections, even current distribution, and safe operation by preventing overheating and decoupling faulty cells, thereby preventing chain reactions and explosions.

Implementation Method 1

Where large currents flow, a great deal of heat is generated, the transfer of which to the battery cells must be avoided

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

The connecting elements (15, 51) are designed in such a way that they melt at a current above a maximum charging or discharging current, with the result that the connection between the connecting elements (15, 51) and the connection structures (14) is interrupted

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP3140874B1Battery pack and method for assembling a battery pack
Publication Date: 2022.09.21 H TECH AG
  • EP3140874B1 patent drawingFigure 1~2
  • EP3140874B1 patent drawingFigure 3a~3b
  • EP3140874B1 patent drawingFigure 4~5

AI summary

In order to specify a battery pack that can be simply produced, that provides sufficient heat dissipation during the assembly and during the operation of the battery pack (10) and a reliable electrical connection between the connection structures (14) and the connection contacts (33, 34) of the battery cells (11), and that copes with the failure of an individual battery cell (11), a battery pack (10) is specified, comprising: at least two battery cells (11), wherein each battery cell (11) has a positive and a negative electrical connection contact (33, 34), wherein a connection structure (14) is associated with at least the electrically positive connection contacts (33) or the electrically negative connection contacts (34) of the battery cells (11), wherein each battery cell (11) is connected to the connection structure (14) by means of at least one connection element (15, 51), wherein a cross-section of each connection element (15, 51) is matched to a predetermined maximum current of a battery cell (11), wherein the connection element (15, 51) is fastened to a side of the connection structure (14) facing the battery cells (11). Each connection structure (14) has a current strength that corresponds to the sum of the individual currents of each connected battery cell (11).