GB 44240-2024 Secondary lithium cells and batteries used in electrical energy storage systems — Safety requirements
1 Scope
This document specifies the requirements for the safety of secondary lithium cells and batteries used in electrical energy storage systems, and describes the corresponding test methods.
This document is applicable to secondary lithium cells and batteries used in electrical energy storage systems (hereinafter referred to as “cells and batteries”). Applications of electrical energy storage systems shall include, but not be limited to:
a) telecommunications;
b) central emergency lighting and alarm systems;
c) stationary engine starting;
d) photovoltaic systems;
e) home (residential) energy storage systems (HESS); and
f) large energy storage: on-grid/off-grid.
This document does not list all equipment with electrical energy storage systems, so those unlisted hereunder may also be within the scope of this document.
For the purpose of this document, the rated energy of secondary lithium battery is generally above 100kWh. See GB 40165 for the safety requirements for batteries with rated energy being 100kWh or lower.
2 Normative references
The following documents contain requirements which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 2423.5 Environmental testing - Part 2: Test methods - Test Ea and guidance: Shock
GB/T 2423.10 Environmental testing - Part 2: Test methods - Test Fc: Vibration (sinusoidal)
GB/T 2423.21 Environmental testing - Part 2: Test methods - Test M: Low air pressure
GB/T 2423.22 Environmental testing - Part 2: Tests methods - Test N: Change of temperature
GB 4943.1-2022 Audio/video, information and communication technology equipment - Part 1: Safety requirements
GB/T 5169.16 Fire hazard testing for electric and electronic products - Part 16: Test flames - 50 W horizontal and vertical flame test methods
GB/T 5169.21 Fire hazard testing for electric and electronic products - Part 21: Abnormal heat - Ball pressure test method
GB/T 17626.2 Electromagnetic compatibility - Testing and measurement techniques - Electrostatic discharge immunity test
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
secondary lithium cell
secondary cell where electrical energy is derived from the insertion/extraction reactions of lithium ions or oxidation/reduction reaction of lithium between the negative electrode and the positive electrode
Note: The cell typically has an electrolyte that consists of a lithium salt and organic solvent compound in liquid, gel or solid form and has a metal or a laminate film casing. It is not ready for use in an application because it is not yet fitted with its final housing, terminal arrangement and electronic control device.
[Source: IEC 63056:2020, 3.7]
3.2
large secondary lithium cell
secondary lithium cell with total mass exceeding 500g
Note: This term is simply referred to as “large cell” in this document.
3.3
cell block
group of cells connected together in parallel configuration with or without protective devices (e.g. fuse or positive temperature coefficient (PTC) device) and monitoring circuitry
Note: It is not ready for use in an application because it is not yet fitted with its final housing, terminal arrangement and electronic control device.
[Source: IEC 63056:2020, 3.8]
3.4
module
group of cells connected together in a series and/or parallel configuration with or without protective devices (e.g. fuse or positive temperature coefficient (PTC) device) and monitoring circuitry
[Source: IEC 63056:2020, 3.9, modified]
3.5
battery pack
energy storage device which comprises one or more cells or modules electrically connected
Note 1: It has monitoring circuitry which provides information (e.g. cell voltage) to a battery system.
Note 2: It may incorporate a protective housing provided with terminals or other interconnection arrangement.
[Source: IEC 63056:2020, 3.10, modified]
3.6
battery system
battery
system which comprises one or more cells, modules or battery packs
Note 1: It has a battery management system capable of controlling current in case of overcharge, overcurrent, overdischarge, and overheating.
Note 2: Overdischarge cut off is not mandatory if there is an agreement between the cell manufacturer and the customer.
Note 3: The battery system may have cooling or heating units, some of which have charge-discharge module, inverter module, etc.
Note 4: More than one battery system may constitute a larger battery system.
[Source: IEC 63056:2020, 3.11, modified]
3.7
large secondary lithium battery
secondary lithium battery with total mass exceeding 12kg
Note: This term is simply referred to as “large battery” in this document.
3.8
battery management system (BMS)
set of protection functions associated with a battery to prevent overcharge, overcurrent, overtemperature, under-temperature and, if applicable, overdischarge and which monitors and/or manages its state, calculates secondary data, reports that data and/or controls its environment to influence the battery’s safety, performance and/or service life
Note 1: The over-discharge cut-off is not mandatory if an agreement are made between the battery manufacturer and the customer.
Note 2: The function of the BMS can be assigned to the battery pack or to equipment that uses the battery.
Note 3: The BMS can be divided and it can be found partially in the battery pack and partially on the equipment that uses the battery.
Note 4: The BMS is sometimes also referred to as a battery management unit (BMU).
Note 5: Example for location of BMS and composition of battery system are given in Figure 1.
[Source: IEC 63056:2020, 12, modified]
4 Test conditions
4.1 Applicability of tests
The tests specified in this document shall be carried out only when it comes to safety.
Unless otherwise specified, samples are not required to be functional after the tests.
4.2 Environmental conditions of tests
Unless otherwise specified, the tests are generally conducted under the following conditions:
a) Temperature: 25°C ± 5°C
b) Relative humidity: ≤75%.
c) Atmospheric pressure: 86kPa to 106kPa.
4.3 Parameter measurement tolerances
The overall accuracy of controlled or measured values, relative to the specified or actual parameters, shall be within the following tolerances.
a) voltage: ±0.5%.
b) current: ±1%.
c) temperature: ±2°C.
d) duration: ±0.1%
e) dimensions: ±1%.
f) mass: ±1%.
These tolerances comprise the combined accuracy of the measuring instruments, the measurement techniques used, and all other sources of error in the test procedure.
4.4 Temperature measurement method
The surface temperature of the sample is measured by the thermocouple method. The temperature test point is selected at the most unfavorable point of temperature, which is taken as the basis for test judgment.
Note: Auxiliary methods such as infrared equipment may be used to find the most unfavorable point.
Contents
Foreword
1 Scope
2 Normative references
3 Terms and definitions
4 Test conditions
4.1 Applicability of tests
4.2 Test environment conditions
4.3 Parameter measurement tolerances
4.4 Temperature measurement method
4.5 Charging and discharging procedures for tests
4.6 Type testing
5 General safety requirements
5.1 General safety considerations
5.2 Safe operating parameters
5.3 Marks and warning instructions
5.4 Safety-critical components
6 Electrical safety of cells
6.1 External short circuit at high temperature
6.2 Overcharge
6.3 Forced discharge
7 Environmental safety
7.1 Low air pressure
7.2 Temperature cycling
7.3 Vibration
7.4 Acceleration impact
7.5 Impact
7.6 Extrusion
7.7 Shallow spike (simulated internal short circuit)
7.8 Thermal abuse
7.9 Drop
8 Electrical safety for battery system
8.1 Requirements for battery management unit/system
8.2 Test samples
8.3 Overvoltage charging control
8.4 Overcurrent charging control
8.5 Undervoltage discharging control
8.6 Overheat control
9 Other requirements
9.1 Resistance to abnormal heat
9.2 Casing material of a battery system that can be transported for installation or maintenance
9.3 Electric insulation check during transport and installation
9.4 Short circuit protection during transport and installation
9.5 Protection for reverse connection
9.6 Electrical strength resistance of battery system
9.7 Thermal runaway of battery and thermal diffusion test of battery system
Annex A (Normative) Test sequence
Annex B (Normative) Thermal runaway test procedure
B.1 Test object
B.2 Test method
Annex C (Informative) Procedure of diffusion test by laser radiation (see 9.7)
C.1 General rule
C.2 Test conditions
Annex D (Informative) Procedure of diffusion test by a method other than laser
D.1 General
D.2 Test conditions
D.3 Method for initiating thermal runaway
D.4 Example of procedure of diffusion test by internal heating
Bibliography
