Case Study: End-to-End Development of an Innovative Charge Port Indicator

Project Background

Problem Statement

The Charge Port Indicator serves as an intelligent visual interface for EV charging, providing real-time feedback on the charging status, charge port door state detection, and cord unlock request process functionality. Existing solutions often suffer from issues such as poor illumination, uneven light distribution, limited diagnostics, non-intuitive interfaces, and insufficient durability, leading to user errors and dissatisfaction.

Project Objective and Requirements

The objective was to develop a Charge Port Indicator that meets automotive standards while improving user clarity and functionality.

• Intuitive and clear illumination of charging status using color and lighting pattern of RGB LEDs
• Compliance with automotive waterproofing and durability standards
• Homogeneous lighting, diagnostic features, and seamless vehicle network integration
• Cost-efficient design optimized for mass production and reliability

Design and Development Phase

1. Optical Design Challenges and Solutions

A key focus was achieving homogeneous and precise illumination. Earlier designs relied heavily on multiple LED to indicate charge status.

• Spectrometer-Assisted Calibration: A specialized spectrometer was introduced to calibrate the target color, ensuring consistency in the final product.

2. Electronics and Software Development

The CPI serves as a visual communication tool, reflecting the vehicle’s charging status in real-time. Key electronic design elements included:

• Microcontroller Integration: The CPI was engineered to interface directly with the vehicle’s charge control management, receiving charging status signals via LIN communication
• Self-Diagnostic Capabilities: A built-in self-check mechanism detects LED malfunctions and button failures.
• Firmware and Calibration Algorithm: Custom software algorithms were developed to calibrate LED output dynamically, to comply with OEM color specifications.
• Independent control of lighting intensity and color mapping: Intensity and color outputs are fine-tuned to meet design and functional requirements.
• Configurable animation modes: Pulsing, ramping, and static indication to represent different charging phases tailored to OEM design requirements.

3. Mechanical and Environmental Considerations

Given the exposure of the Charge Port Indicator to external elements, robust mechanical design was essential:

• Waterproofing Solution: A high-precision pressure pin sealing met IP67 waterproofing standards.
• Durability Testing: The module underwent rigorous testing, including thermal cycling, vibration resistance, and prolonged exposure to environmental conditions (-40°C to 85°C)

Technical Implementation

1. Charging Status Indication

The CPI utilizes RGB LEDs to indicate various charging states:

• White (Courtesy Light): Illuminates when the charge port door is opened
• Blue (Active Charging): Pulsing effect to indicate charging in progress
• Green (Full Charge): Static illumination indicating charging completion
• Red (Error Condition): Indicates charging fault or system error

2. Charge Port Door and Unlock Mechanism

• Hall Sensor Integration: Detects door open/close status and wakes up the vehicle
• Unlock Button: Backlit for visibility, controlled via LIN interface

3. Power and Thermal Management

To optimize efficiency and durability, APAGCoSyst implemented:

• Low Power Consumption Design: Consuming less than 125µA in sleep mode
• Temperature Derating Algorithm: Prevents overheating and ensures longevity
• Integrated Circuit Protection: Ensures stable operation under fluctuating voltage conditions

Manufacturing and Industrialization

Transitioning to production required stable and scalable processes. The APAGCoSyst team implemented proven manufacturing processes to transition efficiently from development to production:

• Automated Assembly and Calibration: To guarantee uniform LED output, end-of-line calibration was automated, incorporating spectrometer measurements for precise color tuning.
• EMC/ESD Compliance: To prevent electrical interference.
• Leak Testing Implementation: Advanced leak detection systems were introduced to validate the waterproofing integrity of each unit.
• Scalable Production Strategy: The manufacturing process was optimized for scalability, ensuring efficient cost management while maintaining high quality.

Challenges and Overcoming Design Constraints

1. Adapting to Evolving Requirements

Multiple specification updates during the development stage required APAGCoSyst to adapt quickly and re-optimize LED control algorithms and thermal management strategies.

2. Balancing Cost and Performance

By reducing component count and integrating multiple functionalities into a single module, APAGCoSyst achieved a more cost-effective solution without compromising on performance.

Results and Market Impact

• Significant improvement in BOM cost compared to prior solutions
• Compatibility with multiple EV platforms
• Improved visibility and intuitive feedback for users
• Reliable performance in harsh conditions
• Scalable design adaptable to future applications
• Consistent quality enabled by automated production and validation processes

Future Outlook

While the charge port indicator proved its value as an essential EV component, further opportunities lie in exploring its integration into other vehicle systems or external components like charging guns. By leveraging its expertise in R&D and production, APAGCoSyst is well-positioned to adapt to evolving market demands and establish new benchmarks in EV accessory design.

Building on the success of this project, APAGCoSyst is now expanding its expertise into advanced optical designs for upcoming automotive projects, such as premium vehicle charge indicators with customized illumination effects. This could include advanced projection lighting, adaptive charging indicators, and augmented reality heads-up displays to deliver clearer, more intuitive charging feedback to EV users. The lessons learned from this development are shaping future innovations, solidifying APAGCoSyst’s position as a leader in automotive lighting and electronics.

Conclusion

This case study demonstrates APAGCoSyst’s comprehensive approach to developing automotive electronics from initial concept to production. By integrating optical engineering, software control, and robust manufacturing processes, APAGCoSyst delivers dependable and user-centered solutions for OEMs seeking advanced EV components. The methodologies and insights gained from this project are guiding future innovations in the automotive lighting domain.

Join us and explore the world of electronic control units

APAGCoSyst is a leading supplier of electronics for the automotive, medical, and industrial sectors. Our state-of-the-art, high-quality production is flexible and responsive with products ranging from simple assembled PCBs to packaged and finished components. We specialize in designing and manufacturing electronic control units (ECUs), lighting, and electronic manufacturing services (EMS), as well as providing top-notch industrial automation services. We are driven to deliver excellence as a global partner for our customers. Join us and explore the world of electronic control units.To learn more about our services, visit our website at www.apagcosyst.com. If you are interested in our services, contact us via email at info@apagcosyst.com.