GB/T 43691.1-2024Fuel cell modules - Part 1: Safety (English PDF)

4.1 General security policy

Manufacturers should conduct the following written risk analysis.

a) Identify all reasonably foreseeable hazards, hazardous situations, and hazardous events within the lifespan of the fuel cell power generation system (see Annex A for a list of typical hazards).

b) Assess the risks of various hazards based on their likelihood of occurrence and expected severity.

c) To the extent possible, eliminate or reduce the two factors of risk assessment (likelihood and severity) to an acceptable level of risk by.

1) The intrinsic safety design of structures and their methods; or

2) Using passive control (such as safety barriers, exhaust valves, thermal cut-off devices, etc.) to ensure safe energy release without enhazarding the surrounding environment, or using safety related control functions;

3) For risks that cannot be reduced in 1) and 2), signs, warnings, or professional training should be provided to personnel working in hazardous areas to master relevant response measures.

To ensure functional safety, the required severity level, performance level, or control function level should be determined and designed based on the following requirements.

- IEC 62061 (or GB/T 16855.1) is applicable to applications that comply with GB/T

5226.1;

- IEC 60730-1 or ISO 23550 is applicable to household appliances that comply with

IEC 60335-1, including residential, commercial, and light industry;

- GB/T 20438 (all parts) is for other applications.

Use the following standards to guide the Failure Mode and Effects Analysis (FMEA) and Fault Tree Analysis methods.

- IEC 60812;

- SAE J1739;

- IEC 61025.

The evaluation should also include the following possible risks.

- Temperature of battery stack or module;

- Battery stack or module and/or battery voltage;

- The pressure of the compressed parts.

If the design involves hazards other than those listed in Annex A, they should be considered and covered.

4.2 Design requirements

4.2.1 General

The fuel cell module should be designed according to the risk assessment of the fuel cell module manufacturer. All components should.

a) Adapt to the expected temperature, pressure, flow rate, voltage, and current range for the intended use;

b) Capable of withstanding the reactions, processes, and other conditions encountered in the intended use.

For the materials and thickness used in fuel cell modules, accessories, stack wiring terminals, and integration methods of various components, their structure and operating characteristics should not undergo significant changes under normal installation and use conditions within a reasonable lifespan. All components of the fuel cell module should be able to adapt to the mechanical, chemical, and thermal conditions that end users may encounter during normal use of the product.

The casing of fuel cell modules should comply with the requirements of GB/T 4208 to adapt to system applications. The fuel cell module should execute the corresponding IP code.

4.2.2 Characteristics under normal and abnormal operating conditions

The fuel cell module should be designed to withstand all normal operating conditions defined in the manufacturer's specifications without damage. Abnormal operating conditions should be handled according to the provisions of 4.1.

4.2.3 Leakage

Depending on the design, there may be a possibility of flammable gas or liquid leakage (see 5.3 for testing). The gas leakage rate of fuel cell modules under normal and abnormal operating conditions should be included in the specification document for the fuel cell system integrator to determine the minimum ventilation capacity of the required ventilation system [see 7.4.1r)].

The internal fault mode of the fuel cell stack, "crossover", should be included as one of the risk assessment contents in section 4.1.According to the results of the risk assessment, measures should be taken to detect or prevent "fuel crossover" in accordance with the relevant standards given in 4.1, such as "battery voltage monitoring", to meet the requirements of functional safety.

If there is no crossover protection in the fuel cell module, the product manual should specify the safeguarding devices or operating procedures that the system integrator should provide.

NOTE. The classification of hazardous areas is specified in IEC 60079-10-1.

4.2.4 Pressure application

If the fuel cell module includes airtight and pressurized components, these components should comply with the safety regulations of the corresponding national standards.

The pressurized operating conditions that may cause external hazards to the module should be identified (see 4.1), and the information should be communicated to the system integrator.

NOTE. The following module features are as follows.

- Polymer electrolyte fuel cell (PEFC) module. Pressure is an important design element in the design of PEFC modules (polymer electrolyte fuel cell stacks). The size, material selection, and manufacturing specifications of PEFC fuel cell stacks are mainly based on strength, rigidity, and stability to meet their static, dynamic, and/or other operational requirements. For example, a design that uses coaxial force to compress hardware leaks before fracture.

- Phosphate fuel cell (PAFC) module. PAFC modules typically operate at atmospheric pressure.

- Molten Carbonate Fuel Cell (MCFC) module. The MCFC module is integrated into the MCFC power generation system for pressurized operation. The MCFC power generation system includes the casing of the MCFC module. It is designed according to relevant national and international specifications and standards for pressure systems. According to the above regulations, the hazard of MCFC module caused by pressurization can be safeguarded by the shell.

- Solid oxide fuel cell (SOFC) module. The SOFC module is integrated into the pressurized operation of the SOFC power generation system. The SOFC power generation system includes the casing of the SOFC module. It is designed according to the relevant national and international specifications and standards for pressure systems.

4.2.5 Fire and auto-ignition

4.2.5.1 General

Measures should be taken to protect the fuel cell module, such as ventilation, gas detectors, controlled oxidation, and operating temperatures above the auto-ignition temperature, to prevent gas leakage from the fuel cell module or its interior from reaching explosive concentrations.

If the protective measures are part of the fuel cell module, the safeguarding level should comply with the requirements of the relevant standards in 4.1.

If the protective measures are not part of the fuel cell module, the fuel cell module manufacturer should provide design standards for such devices (such as the required ventilation rate).

Components and materials classified as flammable gas environments should be constructed or made of flame-retardant materials to prevent external ignition of fuel cell modules. The combustibility of the material should ensure that it will not continue to burn after cutting off the power supply, fuel, and oxidant supply. According to the requirements of GB/T 5169 (all parts), materials that meet V-0, V-1, or V-2 should be selected and validated. Relevant information in accordance with GB/T 51691.1-2017 should be provided, see 7.4.1aa).

NOTE. The s auto-ignition temperature listed in standards such as ISO/IEC 80079-20-1 [7] is the lowest temperature at which a combustible gas mixture ignites. The actual auto-ignition temperature may be much higher than these values. This depends on the surface geometry, material, and actual gas mixture. The auto-ignition temperature required here refers to the auto-ignition temperature at which flammable gases can ignite under any conditions based on the selected material and geometric structure.

The heat resistance and fire resistance requirements of the application standards described in 4.1 should be considered.

It is the fuel cell system integrator's responsibility to protect these live components to prevent electric shock.

4.2.11 Insulation materials and dielectric strength

The design of all dielectrics used between live and non-current-carrying metal parts in fuel cell modules shall comply with the standards given for electrical equipment of the relevant voltage level in 4.2.8.

For mechanical properties that may affect the functional performance of the material, such as compressive strength, the design temperature shall be at least 20 K or 5% (whichever is higher) higher than the maximum temperature under normal operating conditions, but shall not be lower than 80°C.

The determination shall be based on the properties and characteristics of the material as specified by the material manufacturer.

4.2.12 Protective earthing/connection

The following provisions apply to situations where there are differences from the relevant standards mentioned in 4.2.8.

Accessible non-current-carrying metal parts that may become energized due to an electrical fault and cause electric shock or energy hazards should meet the requirements of protective earthing or connection to a common point if the system is applicable.

To ensure good electrical contact, the conductors should be protected against corrosion and designed to prevent loosening and twisting while maintaining contact pressure.

There should be no electrochemical corrosion between metal parts. Based on the conditions of use, storage and transportation, resistance to electrochemical corrosion can be achieved through appropriate electroplating or coating processes.

4.2.13 Shock and vibration

The manufacturer's documentation should include the shock and vibration limits that the fuel cell module is designed to withstand and the corresponding standards.

5.1 General

Use test equipment to simulate the fuel cell system or conduct tests using the fuel cell system itself to obtain the required operating conditions. Equipment used for normal operating tests can be used as conditioning equipment for initial startup of the fuel cell module. The tests should be performed in the following order. Testing under abnormal conditions may be destructive.

Unless otherwise specified, fuel cell modules should be tested under the following environmental conditions.

- Altitude not exceeding 1000 m;

- Ambient temperature 5°C~40°C.

5.2 Impact and vibration test

The fuel cell module shall comply with the shock and vibration test limits specified in the manufacturer's documentation.

NOTE. If the manufacturer does not specify impact and vibration limits, this test need not be performed.

If the fuel cell module can withstand vibration and shock to the standard specified by the manufacturer without damage during the test, it meets the requirements. The fuel cell module is tested after conditioning.

5.3 Gas leakage test

5.3.1 General

This test does not apply to fuel cell module gas leakage in the following situations.

- The operating temperature is higher than the auto-ignition temperature of the flammable gas (see 4.2.5); or

- The fuel cell is placed in an airtight container that complies with relevant national standards.

In cases where a full stack cannot be used, a stack with a reduced but still representative number of cells may be used. Leakage should be calculated based on a ratio of the number of cells.

Proceed as in 5.3.2 or 5.3.3.

5.3.2 Flow meter method

The fuel cell module should operate at rated current and reach thermal equilibrium at the maximum operating temperature.

Stop operation after the above conditions are met. Purge the fuel cell module. Close the gas outlet. Reduce the fuel cell module temperature to or below the specified minimum operating temperature. Pressurize the fuel cell module with standard anode gas or an

......