Battery Pack Connection Pad Structure for Cell Swelling Reliability
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Solution Overview
Problem
Existing battery packs face challenges in maintaining reliable electrical connections between connection lines and circuit boards, especially when battery cells swell, leading to deformation and potential disconnection.
Innovation Solution
The battery pack design includes a connection line with a link line extending from the battery cell to the circuit board and a board connection pad that features outer soldering portions, a gas discharge hole, and an inner soldering portion, enhancing coupling strength and stability even under deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a simple connection structure is used between connection line and circuit board, then manufacturing cost is reduced, but electrical connection reliability deteriorates when battery cells swell
Solution Approach 1:
The connection structure is divided into multiple functional regions: outer soldering portions for initial connection, gas discharge holes for pressure relief, and inner soldering portions for reinforced connection. This segmentation allows each region to address specific failure modes while maintaining overall simplicity and manufacturability.
Solution Approach 2:
Gas discharge holes are pre-formed in the board connection pad to provide pressure relief pathways before swelling occurs. This beforehand cushioning prevents solder joint failure by allowing gas to escape during battery cell swelling, maintaining electrical connection reliability without complex additional structures.
2Device complexity
If the board connection pad uses a simple flat structure, then manufacturing process is simplified, but coupling strength decreases under deformation
Solution Approach 1:
The board connection pad is segmented into multiple soldering portions (outer and inner) distributed across different regions. This segmentation provides multiple attachment points that distribute mechanical stress, maintaining coupling strength under deformation while keeping the overall structure simple and manufacturable.
Solution Approach 2:
Different regions of the board connection pad have different qualities: outer soldering portions provide initial anchoring, gas discharge holes provide pressure relief, and inner soldering portions provide reinforced connection. This local quality differentiation enhances coupling strength under deformation while maintaining manufacturing simplicity.
3Reliability
If outer soldering portions are formed concave toward the outside, then soldering reliability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The concave shape of outer soldering portions is designed beforehand to naturally guide and contain solder material during the soldering process. This beforehand cushioning effect improves soldering reliability by preventing solder bridging and ensuring proper solder fillet formation, while the standardized concave geometry keeps manufacturing precision requirements within normal tolerances.
Data Source
AI summary
This application relates to a battery pack including a battery cell, a circuit board configured to collect state information about the battery cell, and a connection line configured to transmit the state information about the battery cell to the circuit board and including a link line and a board connection pad. The link line extends from a side of the battery cell toward the circuit board, and the board connection pad extends from a first end portion, to which the link line is connected, and is coupled to the circuit board while facing the circuit board. The board connection pad includes outer soldering portions formed in an outer region of the board connection pad and concave toward the outside of the board connection pad and a gas discharge hole formed in a closed loop shape in an inner region of the board connection pad.