■ Technology Overview
The development targets the issues of safety, reliability, performance, and cost down of electric vehicles caused by distortion of battery power estimation.
Ex: Mileage anxiety, remaining mileage, low battery power, etc.
■ Solution
▣ Accurate Battery Information - Accurate Mileage Information Technology
▣ Low-Cost Battery Conductive Bus Design with Wire Bonding Feature
Develop low-cost spot welding process with anti-vibration, fuse, to avoid the nickel sheet clinging to the electrode surface and improve the quality of spot welding.
Current Technologies
1. Problems of cheap nickel sheet spot welding process
• Quality control difficulties of solder joints and requirement of multi-points soldering
• Poor safety due to the nickel flake being placed close to the electrode surface
• Poor vibration resistance of solder joints and easily get damage by stress
• High short-circuit current when the core fails, no fuse mechanism for the nickel sheet
• Advantages: low cost of equipment and process (<1 million)
2. High cost wire bonding process
• Advantages: Good welding quality, busbar and electrode isolation, has the High safety(with fuse function, Fuse blows when abnormal), and good anti-vibration feature
• Disadvantages: High cost of equipment (about 20 million)
▣ Cell Safety Technology－Anti-Thermo-Propagation Materials and Mechanism Design
▣ 600V High-Voltage Electric Bus Battery System Technology - Replaceable, Easy to Repair Battery Pack Management Technology
High Voltage Battery Management System: Decentralized BMS Management Architecture
This architecture can be extended to large energy storage systems in the MWh class with multiple highvoltage battery systems connected in parallel.
▣ Active Balance Control System and Verification
The system is equipped with self-designed low-cost balancing control circuit and control logic. It allows continuous operation of charge, discharge or resting after completing balancing detection.
It can efficiently reduce the difference between cell voltages in the battery pack, which is especially suitable for the applications of large battery systems with high voltage and multiple series such as electric buses and large energy storage.
The balancing current can be developed according to the system specification, and the maximum balancing current of a single channel can reach 2A.
1. Simulation of battery charging/discharging with actual scaled down vehicle data with recharge during braking
2. In addition to testing general operating conditions, the analysis is specifically focused on remaining capacity and balance control
Industrial Technology Research Institute (ITRI)
Material and Chemical Research Laboratories (MCL)
Dept. of Battery System and Application (N300)