Technical Insights: New Submersible BMS Standard Imminent – NGI Fortifies Deep-Sea Tech Testing

On March 1, 2026, the new national standard GB/T 46162-2025Design Requirements for Lithium-ion Battery Management Systems for Submersibles will be officially implemented.
What testing requirements does the new standard propose? How should one choose the most suitable testing solution? This article breaks it down for you.

Background

In 2025, “deep-sea technology” was included for the first time in theGovernment Work Report, listed alongside commercial aerospace and low-altitude economy as part of strategic emerging industries. As a key component of the deep-sea economy, the market size of deep-sea submersibles has grown from RMB 5.28 billion in 2020 to RMB 16.7 billion in 2024, and is expected to exceed RMB 20.88 billion in 2025.

Electrification has become an important development trend for deep-sea submersibles. As the “battery steward,” the BMS monitors battery status (temperature, voltage, state of charge, etc.) and provides communication, safety, and management control. Its performance directly affects propulsion and safety of the submersible, making it a core component. Therefore, BMS testing for submersibles has become a major industry focus.

Key Points of the New Standard

Scope

The new standard applies to the design of lithium-ion battery management systems used in submersibles, including pressure-resistant BMS installed in pressure-compensated battery cabins and non-pressure-resistant BMS installed in pressure hulls.
Other underwater equipment with lithium-ion battery management systems can reference this standard.

Technical Requirements & Test Methods

The standard proposes requirements for parameter measurement accuracy, battery fault diagnosis, electrical performance adaptability, environmental adaptability, electromagnetic compatibility, etc.
Below, we focus on three major test items:cell voltage, temperature, and electrical performance adaptability.

Cell Voltage

The new standard requires that under atmospheric pressure (ambient pressure ≤ 0.2 MPa, same below), the cell voltage detection accuracy must not be lower than 0.5% FS, and the maximum absolute error must not exceed 10 mV.
Therefore, cell voltage testing should use a battery simulator with an accuracy no less than 3 mV. Considering future needs for higher accuracy, the simulator should ideally achieve accuracy better than 1 mV.

Temperature

The new standard requires that under atmospheric pressure, temperature detection accuracy must not be lower than ±2°C. A programmable resistance card with an accuracy no less than 0.5% should be used for temperature testing.

Electrical Performance Adaptability

Standard Requirements

The new standard defines requirements for DC supply voltage, overvoltage, voltage ramp-down and ramp-up, etc. The test power supply must support fast voltage rise and fall, with rise/fall time ≤ 10 ms.

Interpretation

DC Supply Voltage:
The BMS power supply must support 9–16V / 16–32V input ranges.

Overvoltage:
The BMS power supply must be capable of providing 18V / 36V overvoltage.

Voltage Ramp-Up/Down:
The BMS power supply must support a voltage ramp rate of (0.5 ± 0.1) V/min, or allow adjustment resolution as fine as 25mV.

Instantaneous Voltage Drop:
The voltage rise/fall time must not exceed 10ms.

International Standards Overview

In addition, countries and regions such as the United States and Europe have also introduced BMS-related requirements for marine industries. For example, the American Bureau of Shipping (ABS) standard:

ABS: Requirements for Use of Lithium-ion Batteries in the Marine and Offshore Industries
This standard applies to lithium-ion battery systems used in marine and offshore industries, including main power, emergency power, transitional power, and hybrid applications. It requires the BMS to support cell voltage, current, temperature monitoring, communication, balancing, SOC/SOH estimation, and protection functions.
However, it does not specify explicit performance indicators or test methods.

Testing Solution Requirements Under the New Standard

To meet BMS testing needs across global R&D, manufacturing, third-party testing, and deep-sea submersible operations, a proper BMS test solution should meet at least the following requirements:

Functional & Performance Indicators

Must meet—and preferably exceed—the new national standard to support BMS development in the next 3–5 years.

System Architecture

Software and hardware should be flexible and configurable to satisfy different usage scenarios.

Application Track Record

Products should have long-term, validated deployment with leading customers.

NGI Fortress: All-Network & Global Testing Solution Fortifying Deep-Sea Technology

NGI has been deeply involved in the BMS testing field for many years. The independently developed NES6100 Series BMS Test System is widely used in BMS R&D, manufacturing, third-party testing, and system integration across global submersible, energy storage, and electric vehicle industries.

The solution provides the following customer value: