Stepped Bus Bar Structure for Battery Module Weldability
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Solution Overview
Problem
Current battery modules face challenges in weldability between bus bars and electrode terminals, heat dissipation efficiency, and current loss, particularly due to materials with high electrical resistance, which also complicate manufacturing processes and increase costs.
Innovation Solution
A battery module design featuring a bus bar with a stepped, branched structure and embossed protrusions that allows for improved electrical contact and resistance welding, combined with a copper alloy for enhanced conductivity, and a module housing with protrusions and grooves for easy assembly and secure connection of battery modules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a material with high electrical resistance is used for the bus bar, then weldability with the electrode terminal is improved, but current loss increases and heat dissipation performance degrades
Solution Approach 1:
The bus bar is designed with different materials for different parts: the contact portion (where welding occurs) is made of a material with high electrical resistance to ensure good weldability, while the main body portion is made of a material with low electrical resistance to minimize current loss. This local differentiation of material properties resolves the contradiction between weldability and energy efficiency.
2Reliability
If a material with high electrical resistance is used for the bus bar, then weldability is improved, but thermal conductivity decreases leading to poor heat dissipation
Solution Approach 1:
The bus bar employs local quality differentiation where the contact portion uses high resistance material for weldability while the main body uses low resistance, high thermal conductivity material for heat dissipation. This resolves the contradiction between weldability and thermal performance.
3Loss of energy
If a material with low electrical resistance is used for the bus bar, then current loss is reduced, but the amount of heat generated during resistance welding decreases making welding difficult
Solution Approach 1:
The bus bar is designed with local quality differentiation: the contact portion uses high resistance material to generate sufficient welding heat, while the main body uses low resistance material to minimize current loss during operation. This resolves the contradiction between welding requirements and energy efficiency.
4Reliability
If additional connection members are used to electrically connect multiple bus bars, then electrical connection between battery modules is achieved, but the manufacturing process becomes complicated and time-consuming
Solution Approach 1:
The bus bar integrates multiple functions into a single component: it provides both electrical connection (through the main body portion) and welding connection (through the contact portion with embossed protrusions). This merging eliminates the need for additional connection members and simplifies the manufacturing process.
Solution Approach 2:
The bus bar is pre-configured with the contact portion and embossed protrusions during manufacturing, so that when battery modules are assembled, the electrical and welding connections are already prepared. This preliminary preparation eliminates the need for complex on-site connection processes.
5Reliability
If additional connection members and complicated processes are used to connect bus bars, then electrical connection is achieved, but manufacturing time and costs increase
Solution Approach 1:
The bus bar combines electrical connection and welding connection functions in one component, eliminating the need for additional connection members and reducing manufacturing steps, thereby decreasing manufacturing time and costs.
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 enhances weldability, reduces current loss, and improves heat dissipation, leading to higher energy efficiency, reliability, and simplified manufacturing, while preventing disconnection of electrical connections and reducing material costs.
Implementation Method 1
a contact portion configured to electrically contact and be connected to an electrode terminal formed in one of the plurality of cylindrical battery cells
Implementation Method 2
the material may be a factor that increases current loss in a current generated in a secondary battery and transferred to an external device
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A battery module including a bus bar for increasing weldability between the bus bar and an electrode terminal of a cylindrical battery cell, increasing a heat dissipation efficiency, and reducing current loss is provided. The battery module includes: cylindrical battery cells; a module housing; and a bus bar, wherein the bus bar includes: a main body portion that is positioned at a top or a bottom of the plurality of cylindrical battery cells and has a plate shape having upper and lower surfaces that are broader than a lateral surface of the main body portion in a horizontal direction; and a contact portion that is configured to electrically contact and be connected to an electrode terminal formed in one of the plurality of cylindrical battery cells, extends and protrudes from the main body portion in a horizontal direction, is stepped from the main body portion in a direction toward where the electrode terminal is positioned, and includes a branched structure bifurcated in two directions with respect to a direction in which the contact portion extends and protrudes from the main body portion, wherein an embossed protrusion protruding toward where the electrode terminal is positioned is formed in the branched structure, and a contact area is set to allow a welding rod to establish electrical connection around the embossed protrusion in the branched structure.