Battery Block Contacting via Laser-Heated Ultrasonic Bonding
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Solution Overview
Problem
Existing methods for electrically contacting battery cells in a battery block, such as laser welding and ultrasonic bonding, face challenges due to the hardness, granularity, and lattice structure of the materials involved, leading to impaired battery function and limited success with ultrasonic bonding.
Innovation Solution
A modified ultrasonic bonding method that involves heating a bonding tool directly and using a laser to indirectly heat the connection contact surfaces of the battery cells, followed by pressing a connection conductor against these surfaces and exciting the bonding tool to vibrate ultrasonically, thereby transferring vibrations to the conductor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If laser welding is used to electrically contact battery cells, then the electrical connection can be established, but material is locally heated and/or melted causing spatters and impurities that impair battery function
Solution Approach 1:
The patent replaces the thermal laser welding process with an ultrasonic bonding process. The ultrasonic bonding device uses mechanical vibrations at ultrasonic frequencies to create electrical connections between battery cells and connection conductors, eliminating the need for localized heating and thereby preventing spatters and impurities that would otherwise impair battery function.
Solution Approach 2:
The patent changes the fundamental parameter of the bonding process from thermal energy (laser welding) to mechanical vibrational energy (ultrasonic bonding). By operating at ultrasonic frequencies and controlling the bonding force, the process achieves reliable electrical connections without the harmful thermal effects of laser welding.
2Object-generated harmful factors
If ultrasonic bonding is used to electrically contact battery cells, then no spatters or impurities occur, but the process is not regularly successful due to the resilient, soft, or elastic nature of the substrate and resonant vibrations
Solution Approach 1:
The patent modifies the ultrasonic bonding process by introducing controlled heating of the bonding tool. This temperature parameter adjustment softens the connection contact surfaces of the battery cells, making them more compliant and easier to bond with the connection conductor, thereby significantly improving the success rate of the ultrasonic bonding process.
Solution Approach 2:
The patent applies preliminary heating to the bonding tool before the actual ultrasonic bonding operation. This pre-heating step prepares the connection contact surfaces by making them more pliable, creating optimal conditions for subsequent ultrasonic bonding and ensuring higher success rates.
3Ease of manufacture
If common bonding methods are used on battery cell connection surfaces, then the process is simple, but the hardness, granularity, and lattice structure of the materials make bonding insufficient or impossible
Solution Approach 1:
The patent introduces temperature as a critical parameter to the bonding process by heating the bonding tool. This thermal parameter change softens the hard and granular connection contact surfaces of the battery cells, enabling effective ultrasonic bonding where common cold bonding methods fail, while maintaining process simplicity.
Solution Approach 2:
The patent creates a composite effect by combining heated bonding tool with ultrasonic vibrations. The heated tool surface combined with mechanical vibration energy overcomes the hardness and granularity of the battery cell connection surfaces, achieving reliable bonding that neither method could accomplish alone.
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 method allows for reliable electrical contacting of battery cells using ultrasonic bonding, overcoming material compatibility issues and enabling efficient, cost-effective, and automated production of battery blocks suitable for series production and the automotive industry.
Implementation Method 1
a first connection contact surface of a first battery cell and/or the connection conductor is/are heated locally and indirectly in each case by a laser beam directed toward the bonding tool and provided by a laser
Implementation Method 2
the connection conductor is pressed against the first connection contact surface of the first battery cell with the aid of the bonding tool
Implementation Method 3
the bonding tool is excited to vibrate ultrasonically, the ultrasonic vibrations being transferred from the bonding tool to the connection conductor
Data Source
AI summary
An ultrasonic bonding method for electrical contacting a plurality of battery cells of a battery block. A first connection point is produced in that a bonding tool is heated directly, and a first connection contact surface of a first battery cell and/or a connection conductor is/are heated locally and indirectly by a laser beam directed toward the bonding tool. The connection conductor is pressed against the first connection contact surface of the first battery cell. The bonding tool is excited to vibrate ultrasonically, the ultrasonic vibrations being transferred from the bonding tool to the connection conductor. A second connection point is produced in that the connection conductor is pressed against a second connection contact surface of a second battery cell of the battery block or a common connection contact of the battery block by the bonding tool and excited to vibrate ultrasonically.