GB/T 44233.5-2025Safety requirements for secondary batteries and battery installations - Part 5: Safe operation of stationary lithium-ion batteries (English PDF)

3.1 Terms and definitions

3.1.1 Secondary lithium cell/cell

A storage battery that derives its electrical energy from the intercalation/deintercalation of lithium ions or the oxidation/reduction of lithium between the negative and positive electrodes.

NOTE 1.The cell typically has an electrolyte composed of lithium salts and organic solvent compounds in liquid, gel, or solid form; and has a metal or laminated thin-film casing.

NOTE 2.The cell is not yet ready for application because it lacks its final casing, electronic control unit, and terminals.

3.1.2 Home energy storage system; HESS

Stationary battery system that is used in or near single-family or multi-family homes, or for use as internal energy storage devices within a home.

NOTE. Home energy storage system is typically installed in rooms not designed as electrical service rooms or battery rooms.

3.1.3 Battery energy storage system; BESS

A stationary system for storing and converting electrical energy, containing the components required for this function, particularly the battery, power conversion system, and energy management system.

NOTE 1.Safety features and the casing are typically also part of the BESS.

NOTE 2.The power conversion system may be an AC/DC converter or a DC/DC converter used to charge or discharge the battery.

4.1 General

Safety regulations for the installation of batteries and battery packs shall comply with IEC

62485-1.Measures shall be taken in the charging equipment for stationary batteries to prevent direct contact (basic protection) and indirect contact (fault protection) with dangerous voltages.

These measures are described in detail in IEC 60364-4-41 and IEC 61140.The following subclauses describe typical measures and corresponding adjustments for battery installation.

Equipment standard IEC 61140 applies to batteries and DC power distribution circuits located inside equipment.

4.2 Basic protection

In battery installation, basic protection against contact with live parts shall be ensured in accordance with IEC 60364-4-41.

The following protective measures apply.

--- Protection through insulation of live parts;

--- Protection through barriers or fences;

--- Protection using obstacles;

--- Protection by placing the battery in an inaccessible location.

It is explicitly permitted that batteries be protected by obstacles or placed in inaccessible locations during installation. Batteries with a maximum voltage between terminals greater than

DC 60 V but not exceeding DC 120 V and/or a maximum voltage of the terminals to the ground greater than DC 60 V but not exceeding DC 120 V shall be placed in restricted access locations;

while batteries with a maximum voltage higher than DC 120 V shall be placed in locations with restricted access achieved by locking or other equivalent means. Doors to battery compartments and battery rooms are considered obstacles and shall be marked with warning labels as per 11.1.

Batteries with a maximum voltage less than or equal to DC 60 V do not require basic protection, provided the entire installation meets the requirements for Safe Extra Low Voltage (SELV) and

Protective Extra Low Voltage (PELV) (see 4.4.2).

If barriers or fences are used for protection, the minimum required protection level shall comply with IP2X or IPXXB in IEC 60529.

4.3 Fault protection

4.3.1 General

In battery installations, fault protection shall be implemented in accordance with IEC 60364-4-

41.One or more of the following measures shall be selected.

--- Protection by automatic power disconnection;

--- Protection by using Class II equipment or equivalent insulation;

--- Protection by non-conductive locations (for specific applications only);

--- Protection by ungrounded local equipotential bonding (for specific applications only);

--- Protection by electrical isolation.

The maximum contact voltage shall not exceed DC 120V (according to IEC 60449, IEC 60364-

4-41 and IEC/TS 61201). If this voltage is exceeded, other suitable protection measures shall be implemented. Under normal operating conditions, abnormal operating conditions, and single-fault conditions (except for safety measure failures), the contact voltage or contact current of all ungrounded accessible conductive parts shall be measured.

Some of these protective methods require a protective conductor. The protective conductor, or a conductor with protective functions, shall not be disconnected by a switching device.

Switching devices are not permitted in the protective conductor. The protective conductor shall not contain overcurrent protection devices (according to IEC 60364-4-41). For the dimension label of the protective conductor's cross-sectional area, see IEC 60364-5-54.

Battery racks or battery compartments made of metal shall be connected to the protective conductor or insulated from the battery and its installing location. This insulation shall comply with the insulation protection conditions of IEC 60364-4-41.For creepage distance and clearance requirements, according to IEC 60664-1, the rated impulse withstand voltage of a

Class II overvoltage source shall be used as the nominal voltage used by the power supply system (according to Table F.1 in GB/T 16935.1-2023 - Rated impulse withstand voltage of equipment directly powered by the mains).

NOTE. For equipment powered by AC power, the test voltage is equal to the equipment's rated voltage or the upper limit of its rated voltage range. For equipment powered by DC power, the test voltage is equal to the equipment's rated voltage or the upper limit of its rated voltage range.

The test voltage is equal to the highest nominal voltage of the AC power supply in the region where the equipment is used (e.g., 220V in China; 230V in Europe; 120V in North America).

The following protective devices (rated DC) applicable to power systems shall be DC powered.

a) Fuses;

b) Overcurrent protective devices;

c) Residual current protective devices conforming to IEC 60755 shall be Type B suitable for

DC fault currents;

d) Insulation monitoring devices (e.g., in IT systems);

e) Fault voltage operating protective devices (according to IEC 60364-4-41).

4.3.2 Protection by automatic power disconnection

4.3.2.1 TN system

In a TN system (according to IEC 60364-4-41), the positive or negative terminal of the battery equipment (see Figures 1 and 2) or the neutral point (or, in special cases, a non-neutral point) shall be grounded.

Exposed conductive parts of the equipment shall be connected to the protective conductor (PE)1), the protective neutral conductor (PEN)2), or the functional grounding and protective grounding conductor (FPE)3). These conductors are connected to the contacts on the battery that have a ground potential. Additional grounding of the protective conductor may be provided as needed to ensure that its potential deviates as little as possible from the ground potential.

For fixed-installation electrical equipment, the power supply shall be disconnected within 5 s of a fault occurring.

NOTE 1.For portable equipment and socket circuits, the requirements of IEC 60364-4-41 apply.

NOTE 2.PE conductor - a conductor provided for safety purposes, such as protection against electric shock.

NOTE 3.PEN conductor - a conductor that functions as both a protective grounding conductor and a neutral conductor.

1) For the definition of protective grounding conductor, see IEC 60364-5-54.

2) Refer to IEC 60364-5-54

3) The definitions of functional grounding and protective grounding conductors can see IEC 60950-1.

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