I. Background of Unmanned Underwater Vehicles

   Unmanned submersibles are devices that navigate underwater without human operation and are controlled by remote control or automatic control. They mainly refer to intelligent systems that replace divers or manned small submarines to perform high-risk underwater operations such as deep-sea exploration, rescue, and mine clearance. They are also known as "diving robots" or "underwater robots".
▲ Classification: According to the application field, it can be divided into military and civilian; It can be classified by size into portable, light, heavy and giant, etc. According to their functions, they can be classified into reconnaissance type, anti-submarine type, anti-mine type, Marine investigation type, etc.
▲ Military field: Capable of carrying out reconnaissance and surveillance tasks; In anti-submarine operations, anti-submarine warning lines can be formed. In terms of anti-mine operations, it is used for clearing mines. It can also be used as bait to deceive enemy submarines or to lay mines for attacks, etc.
▲ Civilian field: It is used for operations such as sunken ship salvage, deep-water exploration, and underwater cable laying. It can also be used for offshore oil investigation and communication line inspection. Real-time exploration of the seabed is possible.
New energy lithium batteries, with their advantages of high energy density, light weight, long cycle life and environmental friendliness, have gradually become the preferred solution for unmanned underwater vehicle systems. This solution is designed to meet the application requirements of lithium batteries in unmanned equipment projects, ensuring that lithium batteries provide safe, efficient and customized power solutions for their equipment.

II. Analysis of Equipment Demand Characteristics
1. Equipment application characteristics
▲ Equipment type: Real-time monitoring operations in environments such as lakes and oceans.
▲ Working environment: Temperature range, from -40℃ to +70℃, high humidity, high-pressure environment, etc.
▲ Power demand: Large continuous/peak power, long battery life, and the voltage platform generally adopts high-voltage platforms such as 36V or 48V.

2. Core requirements for lithium batteries
▲ High safety: Meets the explosion-proof, shock-resistant, waterproof and anti-interference requirements of exploration equipment under harsh working conditions.
▲ Long cycle life: ≥2000 times (80% capacity retention rate).
▲ Fast charging: Supports 1 to 2 hours of fast charging, suitable for high-intensity work.
▲ High-power discharge: The battery supports continuous high-current discharge, meeting the high-current requirements of high-power devices and ensuring their continuous and stable operation.
▲ Intelligent management: The BMS (Battery Management System) is equipped with functions such as overcharge protection, overdischarge protection, overcurrent protection, short-circuit protection, temperature protection, and fault diagnosis, making the battery more intelligent.
▲ Discharge temperature range: -40℃ to +70℃. In a low-temperature environment of -40℃, the battery's discharge efficiency is over 70%. A wider range of ambient temperature adaptability.
▲ Charging temperature: -20 ℃ to +50℃ range, with a wider adaptability to environmental temperatures.

III. Scheme Design
1. Battery selection
▲ Cell types: Ternary lithium batteries (ultra-low temperature, high energy density, high safety), lithium iron phosphate batteries (ultra-low temperature, high safety, long life), sodium-ion batteries (high safety, long life, good low-temperature performance). Different system cells are selected and matched according to different application scenarios.
▲ Battery combination configuration structure: Series and parallel schemes are designed based on the required voltage and capacity of the equipment to meet the requirements of different output voltage platforms.
▲ Structural design: IP68 protection grade, shock-resistant structure, explosion-proof enclosure (suitable for extreme environments or flammable and explosive environments).

2. BMS Management System
Core functions:
▲ Real-time monitoring of the voltage, temperature, SOC (State of Charge), and SOH (State of Health) of individual battery cells.
The battery charging active balancing technology enhances the consistency of usage among battery cells and extends the lifespan of the battery pack.
▲ The I2C/SMBUS/CAN/RS485 communication interface enables data interaction and communication with the main control system of the equipment.
The Coulomb computing method makes the battery SOC more accurate and the battery smarter.

3. Charging solution
▲ Charging equipment: Customized smart charger/charger/charging cabinet, supporting constant current and constant voltage (CC-CV) charging.
▲ Charging strategy: Select fast charging or slow charging mode based on the working conditions to prevent battery overload.
▲ Intelligent control and management: Based on the technical performance characteristics of the battery, the battery charging process and fault diagnosis are intelligently controlled.

IV. Safety and Compliance
1. Safety protection
▲ Thermal management: By adopting a reasonable structural layout, thermal runaway is reduced. A liquid cooling system can be used (for high-power scenarios) to ensure temperature uniformity during battery use and effectively control battery thermal runaway.
▲ Fault protection: Multiple hardware protection mechanisms such as overcharge, overdischarge, short circuit, overcurrent, and over-temperature.
▲ Fault protection: Multiple hardware protection mechanisms such as short circuit, overcurrent, and over-temperature.
▲ Explosion-proof certification: The design can pass various safety regulations certifications.

2. Standard compliance
▲ It complies with national standards such as GB31241-2022 (Safety Technical Specification for Lithium-ion Batteries and Battery Packs for Portable Electronic Products), GB 17761-2024 (Safety Technical Specification for Electric Bicycles), GB/T 34131 (Lithium Batteries for Power Storage), GB 38031 (Safety Requirements for Batteries for Electric Vehicles), etc.
▲ How to obtain domestic and international certifications: GB certification, UN38.3 certification, UL certification, IEC certification, CE certification and other various certification requirements;

V. Project Implementation Plan

VI. Economic Benefit Analysis
1.In terms of cost
▲ The initial investment in spare lithium batteries is relatively large, but they have an absolute advantage in terms of long-term usage costs.
2. Energy-saving benefits:
▲ The charging efficiency is over 95%, which can significantly reduce energy consumption compared with AC power supply.
3. Maintenance cost:
▲ Maintenance-free design reduces circuit maintenance and personnel costs.

VII. After-sales Service
1. Warranty period: 1 to 5 years of after-sales warranty, with a lifespan of 500 to 2,000 cycles or more (whichever comes first).
2. Remote monitoring: According to the actual demand status, the cloud platform provides real-time monitoring of the battery status and early warning of potential faults.
3. Emergency Response: Respond within 4 hours, provide solutions within 8 hours, and offer on-site technical support within 24 to 48 hours.

Hint:
▲ The plan needs to be refined based on specific equipment parameters (such as voltage, capacity, and size limitations).
▲ If special environments (such as deep sea) are involved, corresponding protective designs need to be added.
▲ It is recommended to conduct joint debugging with the equipment manufacturer to ensure that the battery is compatible with the entire machine system