Wound Secondary Battery Can Connection for Low Resistance and Heat Dissipation
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Solution Overview
Problem
Secondary batteries face challenges with high resistance and inadequate heat dissipation, as well as issues related to electrode meandering during welding, which affect the uniformity of connections and thermal performance.
Innovation Solution
A secondary battery design featuring an electrode assembly with alternately stacked first and second electrodes and a can configuration where non-coated portions protrude to contact protrusion connection parts on the can, allowing direct connection without additional members and improving heat dissipation and resistance characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional electrode assembly with coating is used, then the electrode structure is complete for electrochemical function, but the connection to the can has high resistance and poor heat dissipation
Solution Approach 1:
The patent extracts the connection function from the coated electrode surface by creating a separate non-coated portion that protrudes from the electrode assembly. This extracted connection portion directly contacts the can without requiring additional connection members, thereby reducing resistance and simplifying the connection structure while maintaining the electrochemical functionality of the coated electrode areas.
Solution Approach 2:
The non-coated portion acts as an intermediary element between the electrode assembly and the can. This intermediary structure provides a dedicated electrical and thermal conduction path that bypasses the resistance issues of conventional connections, while the protruding design ensures reliable contact without requiring complex alignment or additional connection components.
2Quantity of substance
If the electrode assembly is wound tightly, then the energy density is high, but the electrode meandering causes welding position deviation
Solution Approach 1:
The patent applies preliminary action by pre-forming the non-coated portion to protrude from the electrode assembly before the winding process is completed. This pre-formed protruding structure anticipates and compensates for any meandering that may occur during winding, ensuring that the connection portion maintains proper alignment and contact with the can regardless of winding variations, thus enabling consistent welding positions.
Solution Approach 2:
The patent applies local quality by creating a non-coated portion with different properties than the coated electrode areas. This local modification provides a dedicated connection zone with optimized electrical and thermal conduction properties, while the protruding geometry of this local region ensures reliable contact with the can independent of the overall winding quality, thereby maintaining welding precision despite tight winding requirements for high energy density.
3Reliability
If additional connection members are used to connect the electrode to the can, then the connection reliability is improved, but the device complexity and resistance increase
Solution Approach 1:
The patent merges the electrode structure with the connection function by integrating the non-coated portion directly into the electrode assembly. This merged structure eliminates the need for separate connection members while maintaining reliable electrical and thermal contact with the can, thereby reducing device complexity and resistance while preserving connection reliability.
Solution Approach 2:
The non-coated portion serves multiple functions simultaneously: it provides electrical conduction, thermal dissipation, and mechanical connection to the can. This multi-functional design eliminates the need for separate dedicated connection members, reducing overall device complexity while maintaining reliable connections through the integrated electrode-connection structure.
Data Source
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AI summary
The present invention relates to a secondary battery. The secondary battery comprises an electrode assembly in which a first electrode, a separator, and a second electrode are alternately stacked, and a can configured to accommodate the electrode assembly, wherein the first electrode is disposed on an end of the electrode assembly in one direction so that a first electrode non-coating portion that is not coated with an electrode active material protrudes more than the separator with respect to a direction of a winding center axis of the electrode assembly, the second is disposed on an end of the electrode assembly in the other direction so that a second electrode non-coating portion that is not coated with the electrode active material protrudes more than the separator with respect to the direction of the winding center axis of the electrode assembly, the can comprises a first can and a second can, the first electrode non-coating portion contacts a first connection part disposed on an end of one side of the first can, and the second electrode non-coating portion contacts a second connection part disposed on an end of the other side of the second can, and at least one of the first connection part or the second connection part comprises a protrusion connection part having a shape protruding in a direction of the electrode assembly.