🔋 Li-Ion Battery Protection PCB

A compact single-cell (3.7 V) Li-Ion battery protection and voltage monitoring PCB designed using KiCad 9.

This project demonstrates the complete PCB design workflow, including schematic capture, PCB layout, routing, copper pour, design rule verification, Gerber generation, and manufacturing documentation.

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📸 Project Banner

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📖 Project Overview

This PCB provides a simple yet reliable protection and monitoring solution for a single-cell Li-Ion battery.

The design includes:

• Reverse-current protection
• Overcurrent protection
• Battery voltage sensing
• Power indication
• Test points
• Manufacturing-ready outputs

The project was developed to demonstrate practical PCB design skills and follows good engineering documentation practices suitable for a hardware portfolio.

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✨ Features

• ✅ Reverse current protection using 1N5819 Schottky diode
• ✅ 500 mA resettable Polyfuse
• ✅ Battery voltage divider for MCU ADC
• ✅ 100 nF analog filter capacitor
• ✅ Green power indicator LED
• ✅ BAT_ADC and GND test points
• ✅ 90 mm × 40 mm PCB
• ✅ Ground copper pour
• ✅ Passed KiCad DRC (0 Errors)
• ✅ Manufacturing-ready Gerber files

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📊 PCB Specifications

Parameter	Value
Board Size	90 mm × 40 mm
Layers	2
Copper Weight	1 oz
Input Voltage	3.0–4.2 V DC
Nominal Voltage	3.7 V Li-Ion
Design Software	KiCad 9
DRC Status	Passed (0 Errors)

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⚡ Circuit Overview

The battery output first passes through a 500 mA resettable Polyfuse, providing overcurrent protection.

The protected voltage is then routed through a 1N5819 Schottky diode, preventing reverse current flow.

The output powers:

• Output connector
• Power indicator LED
• Battery voltage monitoring circuit

Battery voltage is measured using a 100 kΩ / 100 kΩ resistor divider followed by a 100 nF RC filter, providing a stable analog voltage for a microcontroller ADC.

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🔄 Functional Block Diagram

Battery
   │
   ▼
PTC Fuse
   │
   ▼
Schottky Diode
   │
   ▼
BAT_OUT
 ├──► LED Indicator
 └──► ADC Voltage Divider

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🖼️ Project Images

Schematic

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PCB Top View

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3D PCB View

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Gerber Verification

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📁 Repository Structure

docs/
gerbers/
images/
pcb/
references/
releases/
simulation/

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📋 Bill of Materials

See BOM.csv

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✔ Verification

• ERC Completed
• DRC Passed (0 Errors)
• Copper Pour Verified
• Gerbers Verified
• Drill Files Generated
• Fabrication Package Prepared

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🛠 Software Used

• KiCad 9
• KiCad Gerber Viewer
• LTspice XVII
• Git
• GitHub

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🚀 Future Improvements

• DW01A Battery Protection IC
• USB Type-C Charging Circuit
• Reverse Polarity MOSFET Protection
• Battery Fuel Gauge
• JST Battery Connector
• Current Sense Amplifier
• TVS Surge Protection
• Mounting Holes

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📚 Documentation

• Project Report
• Project Specification
• Design Decisions
• Manufacturing Notes
• Component Datasheets
• PCB Design Checklist

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📄 License

This project is licensed under the MIT License.

See the LICENSE file for details.

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⭐ Acknowledgements

Designed using KiCad 9 as part of a hardware engineering portfolio project demonstrating PCB design, documentation, and manufacturing preparation.