Development of a Fast-Charging Li-Ion polimer Battery for StoreDot High-Speed Charging Battery Pack for Electric Vehicles (EVs)

BatteryThermalManagementEVBatteryFastChargingLiIonPolymer

Background and Customer Requirements

In April 2019, StoreDot introduced a revolutionary new type of Li-Ion polymer (pouch) cells capable of achieving incredibly high charge rates—10C charge current, which enables a full charge in just 5 minutes. The goal was to create a fully operational battery pack to demonstrate StoreDot's superior cell technology by powering an electric vehicle (EV).

Client Requirements:

A functional Li-Ion polymer battery pack for EV applications.
Proof of 10C charge rate capability.
Compatibility with a given mechanical casing.
Design and implementation of a charging system to support the high charge rate.

Key Challenges:

Mechanical Constraints: The provided casing was not designed for this type of battery, making it too small to fit all the required cells.
Wiring Challenges: The high current required heavy-duty conductors and wiring, with limited space within the casing.
Heat Dissipation: Extremely high currents generated significant heat, requiring effective cooling solutions.
Charging System: A charger capable of handling the 10C charge rate (130A) was needed.

Design Process:

Maximizing Space

A 3D-printed case extension was designed to fit the battery into the motorcycle seat, maximizing the available volume.
The cells were optimally arranged to minimize the need for busbars and wiring.

Heat Management

Two heat dissipation options were explored:
- Option 1: Air cooling with wide spacing between cells and fans for better airflow.
- Option 2: Conductive plates between cells to transfer heat to the casing.
After testing and simulations, Option 1 (air cooling) was selected for its superior effectiveness.
A custom internal matrix with slots for each cell was designed to maximize spacing, and a 500mm 3D-printed part was created to support this structure.

Wiring and Connectors

Custom-shaped copper conductors were designed to handle currents up to 150A.
Anderson 4×2 PP45-15 pins were used for the 150A charge connector, and a D-type connector was used for balancing.

Demonstrator and Testing

A smaller version of the battery module (6S4P) was assembled using the same matrix design.
Charge/discharge tests were performed, including heat dissipation tests, to validate the design.
High-precision venting strips were added to the casing, aligned with the spacing between the cells, to improve airflow and cooling.

Final Battery Assembly

The final battery pack (14S12P, 51.8V, 13.2Ah) was assembled, with the casing extended using 3D printing to maximize space between cells.
The battery was designed to handle a maximum voltage of 58.8V and a charging power of 7,650W (58.8V × 130A).

Production Process

The production process included cell testing and grouping, assembly of conductors, and integration of the cooling system.
High-precision venting strips were added to ensure proper heat dissipation during operation.

Final solution

The final product was a fully operational Li-Ion polymer battery pack, capable of 10C charging, designed to fit within the constraints of the given mechanical casing.
The battery successfully demonstrated StoreDot’s advanced cell technology in a real-world EV application.

Conclusion

AMICELL successfully delivered a custom-designed battery solution that not only met but exceeded StoreDot's requirements for high-speed charging and heat management. This case study highlights AMICELL’s expertise in developing innovative battery solutions for cutting-edge applications.

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