Battery Pack Busbar Welding for High-Density Cell Assembly

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Solution Overview

Problem

Existing battery packs face challenges in terms of energy density, assemblability, and manufacturing complexity due to the use of multiple components and modularization of battery cells, leading to increased volume and reduced space for accommodation.

Innovation Solution

A battery pack design featuring a simplified structure with busbars extending in a first direction to connect adjacent battery cells, where each cell has a cell lead with distinct parts, and the busbars are connected to these parts via welding, supported by a printed circuit board, reducing the number of components and simplifying the assembly process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple battery cells are modularized by accommodating them in a module case to form battery modules, then the battery pack structure is more stable and easier to assemble, but the volume of the battery pack increases and the space for battery cells decreases, limiting energy density

Engineering Contradiction:
Improvebattery pack structure stabilityVSAvoidbattery pack volume
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent merges the module case and stack frames into a single integrated pack case structure. The pack case directly accommodates multiple battery cells in a stacked arrangement without requiring separate module cases or stack frames, thereby eliminating the volume occupied by these additional components while maintaining structural stability and ease of assembly.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If multiple battery cells are modularized by accommodating them in a module case, then the battery pack structure is more stable, but various components such as module case or stack frames occupy space and reduce the accommodation space for battery cells

Engineering Contradiction:
Improvebattery pack structure stabilityVSAvoidspace for battery cells
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent combines the functions of the module case and stack frames into a single pack case structure. This integrated design eliminates the need for separate module cases and stack frames, thereby maximizing the internal volume available for battery cells while maintaining the structural support and organizational functions previously provided by the removed components.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If a battery module is configured by modularizing multiple battery cells and then accommodated in a pack case, then the manufacturing process becomes more complex involving stack frames, bolts, plates, etc., but the battery pack structure is more organized

Engineering Contradiction:
Improvebattery pack structure organizationVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and removes the unnecessary components (stack frames, bolts, plates) from the battery pack structure. By eliminating these intermediate components, the manufacturing process is simplified while the pack case directly accommodates battery cells in a well-organized stacked arrangement, maintaining structural organization without the complexity of modular assembly.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the structural support functions previously distributed across multiple components (stack frames, bolts, plates, module case) into a single integrated pack case structure. This consolidation simplifies the manufacturing process by reducing the number of parts to be assembled while maintaining the organizational benefits of a structured battery cell arrangement.

Inventive Principle:
Principle #5Merging (Combining)

4Quantity of substance

If pouch-type battery cells are directly stacked without modularization, then the energy density increases due to reduced component volume, but the assemblability decreases and the manufacturing process becomes more difficult

Engineering Contradiction:
Improveenergy densityVSAvoidassemblability
Core Design Contradiction:
Quantity of substanceVSEase of manufacture

Solution Approach 1:

The patent merges the benefits of direct stacking (high energy density) with the advantages of modularization (easy assembly) by creating an integrated pack case structure that provides organizational guidance for stacking pouch-type battery cells. The pack case incorporates features that facilitate straightforward assembly while maintaining the high space utilization achieved through direct stacking without intermediate module cases.

Inventive Principle:
Principle #5Merging (Combining)

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 allows for low-cost manufacturing, high productivity, and enhanced reliability with reduced malfunctions by minimizing components and simplifying the assembly process.

Implementation Method 1

busbars extending in the first direction and configured to electrically connect at least two adjacent battery cells among the plurality of battery cells

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

the busbars are connected to these parts via welding

Methodology Applied
Scientific EffectWelding: Welding

Data Source

PatentEP4611158A1Battery pack
Publication Date: 2025.09.03 LG ENERGY SOLUTION LTD
  • EP4611158A1 patent drawingFigure 1
  • EP4611158A1 patent drawingFigure 2
  • EP4611158A1 patent drawingFigure 3

AI summary

A battery pack may include a plurality of battery cells stacked in a first direction, and busbars extending in the first direction and configured to electrically connect at least two adjacent battery cells among the plurality of battery cells. Each of the at least two adjacent battery cells among the plurality of battery cells may include an electrode assembly, a cover surrounding the electrode assembly, and a cell lead protruding from a side of the cover in a second direction. Further, the cell lead may include a first part disposed closer to the cover than a second part. In addition, a maximum dimension of the second part may be greater than a maximum dimension of the first part in the first direction, and each of the busbars may extend in the first direction to electrically connect adjacent second parts to each other.