Advantages of Laser Soldering for Mobile Phone Battery Boards

Advantages of Laser Soldering for Mobile Phone Battery Boards

Laser soldering is an advanced welding technology used in smartphone battery production, primarily for connecting battery electrodes (anode/cathode), tabs, and PCB components. Below, Songsheng Optoelectronics presents the key advantages and technical process of this innovative method.

Technical Principle

Laser soldering utilizes a high-energy-density laser beam to irradiate target areas on the battery board. The absorbed laser energy converts into thermal energy, causing rapid temperature rise in the welding zone until material melting occurs. Subsequent cooling and solidification form a robust metallurgical bond, achieving reliable interconnections between battery components.

Mobile Phone Circuit Board Diagram

Process Flow

Pre-Welding Preparation: The soldering areas of the battery board undergo thorough cleaning to eliminate contaminants including oils, dust and oxides, ensuring optimal welding quality. The battery board is then precisely mounted in the welding fixture to guarantee positional accuracy of soldering areas for accurate laser beam focusing.

Parameter Configuration: Laser soldering parameters are meticulously adjusted according to the battery board's material characteristics, thickness and specific welding requirements. The laser power typically ranges between tens to hundreds of watts to accommodate various materials and welding depths, while pulse frequency generally varies from tens to thousands of Hertz to regulate laser energy output. Welding duration spans from several to dozens of milliseconds to control laser exposure time, with beam spot diameter adjustable from tens to hundreds of micrometers based on soldering point dimensions.

Welding Operation

The laser soldering process is initiated by activating the equipment, where the laser beam is transmitted through the optical system and precisely focused onto the designated soldering area of the battery board. The welding is performed according to pre-programmed paths and parameters, with two primary modes available: continuous welding and pulse welding. Continuous welding delivers stable heat input and is particularly suitable for extended solder joints, while pulse welding offers superior control over thermal input, making it ideal for spot welding applications or situations requiring minimized heat-affected zones. Throughout the welding process, inert gas shielding (typically argon) is employed to effectively prevent oxidation of the soldered areas.

Quality Inspection

Post-welding quality verification involves comprehensive examination procedures:

• Visual inspection evaluates joint morphology for proper fullness, surface      smoothness, and absence of defects including cold joints, skipped welds, or spatter

• Mechanical strength testing utilizes specialized equipment such as tensile testers to      validate the joint's capability to withstand operational stresses

• Non-destructive testing methods including ultrasonic flaw detection and X-ray inspection are implemented to identify internal imperfections such as porosity or      micro-cracks
  These rigorous inspection protocols collectively ensure the battery board's electrical performance and safety compliance meet stringent industry standards.

Songsheng Optoelectronics Laser Constant-Temperature Soldering System Diagram

Songsheng Optoelectronics Laser Constant-Temperature Soldering System consists of a real-time temperature feedback system, CCD coaxial positioning system, and semiconductor laser. The innovative PID online temperature regulation feedback system effectively controls constant-temperature soldering, featuring real-time high-precision temperature control of the soldering target, ensuring high soldering yield and precision. It is particularly suitable for temperature-sensitive high-precision soldering applications such as micro speakers/motors, electronic microphones, connectors, mobile phone circuit boards, etc.

Laser Soldering for Mobile Phone Battery Boards Offers the Following Advantages:

High Welding Precision:
The laser beam can be focused to extremely small dimensions, achieving micron-level welding accuracy. This is crucial for compact, high-precision products like mobile phone battery boards, enabling precise connections between tabs and battery electrodes while ensuring connection reliability. It effectively minimizes issues like cold solder joints and short circuits.

Minimal Thermal Impact:
As a localized rapid-heating process, laser soldering concentrates heat primarily in the welding zone, significantly reducing thermal effects on surrounding battery materials. This prevents overheating-induced chemical changes in battery components, safeguards battery performance and safety, and eliminates thermal stress-related deformation or other potential quality defects.

Superior Joint Strength:
Laser soldering creates robust metallurgical bonds with high joint strength. The connections withstand various mechanical stresses and vibrations during battery operation, preventing solder joint loosening or detachment over extended use, thereby enhancing battery reliability and lifespan.

Excellent Sealing Performance:
During laser soldering, molten materials rapidly solidify into dense seams with outstanding airtightness. This effectively blocks moisture, oxygen, and other harmful gases from penetrating the battery interior, preventing oxidation or undesirable chemical reactions to maintain stable battery performance.

High Production Efficiency:
The process offers rapid welding speeds, completing multiple joints in minimal time. Laser soldering equipment integrates seamlessly with automated production lines, enabling unmanned operation that reduces manual errors while improving production efficiency and product consistency - ideal for large-scale industrial manufacturing.

Eco-Friendly and Energy-Efficient:
Eliminating the need for chemical fluxes, the process reduces hazardous emissions for improved environmental compatibility. As an energy-efficient method, laser soldering consumes significantly less power than conventional techniques, aligning with sustainable development requirements.