Specialty Wide-Temperature Lithium Battery

Design Proposal for Mobile Field Power Supply

(Keywords: Low-temperature battery, Special battery, Field power supply battery)

1. Introduction

Due to the rapid development of lithium battery technology, its application fields are expanding. The field-type mobile power supply customized by our company features "high energy, high density, high cycle life, and a wide range of operating ambient temperatures." It can operate efficiently in environments ranging from -40°C to 65°C, while being lightweight, portable, dustproof, and waterproof. It can work normally in all weather conditions under harsh environments and is widely used in military communications, measurement and control, field operations, and other fields.

2. Mobile Field Power Supply Design Requirements

Based on the client's requirements and specifications, we aim to design a low-temperature battery pack that pairs with specialized testing equipment. Equipped with safety protection circuits such as temperature protection, we provide a battery solution that ensures the equipment operates in low-temperature and harsh environments.

• Built-in Charger: Adopts a 220V AC interface for convenient power supply.

• Display & Communication: Features a display screen for intuitive battery data reading, and reserves a communication interface to facilitate data exchange between the host machine and the battery.

• Built-in DC-DC Module: Provides a regulated 12V/1A output.

• Portable Design: Compact size, lightweight, and easy to carry.

3. Specific Parameter Requirements

1. Cell Design Requirement: Adopts self-developed proprietary 18650 low-temperature lithium cells, configured in a 4-series, 4-parallel (4S4P) arrangement.

2. Structural Design Requirement: Overall dimensions must be less than 200 x 150 x 100 mm. Requires an aesthetic appearance, overall dustproof, waterproof, and shockproof design. Uses a cold-rolled sheet metal powder-coated shell with aviation connectors. Portable and lightweight.

3. Circuit Design Requirement: Operating temperature range: -50°C to +70°C. Regulated 12V/1A output, AC 220V input. Must support 9 hours of continuous operation on a single charge. Equipped with a display screen to show battery level and other information.

4. Mobile Field Power Supply Design Proposal

1) Sheet Metal Powder-Coated Shell & Plastic Battery Bracket:
Designed with a sheet metal shell that meets the customer's dimensions. The surface is powder-coated in military green to achieve an exquisite appearance, while meeting the requirements for waterproof, dustproof, and shockproof performance. The cells are connected using one-piece nickel strip spot welding, supported by a plastic bracket structure. Copper busbars are used for cross-connection, ensuring excellent overall battery pack impedance and reliability.

2) Protection Board (BMS) Specifications:

3) PTC Overcurrent Protection Sheet:
Primarily designed for secondary protection functions. The PTC resettable fuse offers dual functions of overcurrent protection and automatic recovery. The PTC inside the battery product prevents unsafe high-temperature discharges and high currents.

4) Dedicated Vacuum Waterproof Aviation Connector:
The external interface of the battery adopts a vacuum waterproof connection to meet the customer's waterproof requirements.

5) LA18650-4S4P / 8Ah / 14.8V Lithium Battery Pack:
Utilizing low-temperature cells.

6) Battery Arrangement Plan:

• Customer Overall Dimension: 200 x 150 x 100 mm (Max)

• Battery Configuration: 4S4P