GB/T 44649-2024 English PDF (GBT44649-2024)

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GB/T 44649-2024: Nickel-metal hydride cells and modules used for electric road vehicles - Safety requirements
GB/T 44649-2024
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 29.220.20
CCS K 84
Nickel-metal Hydride Cells and Modules Used for Electric
Road Vehicles - Safety Requirements
[IEC 61982-4:2015, Secondary batteries (except lithium) for the propulsion of
electric road vehicles - Part 4: Safety requirements of nickel-metal hydride cells
and modules, MOD]
ISSUED ON: SEPTEMBER 29, 2024
IMPLEMENTED ON: APRIL 1, 2025
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative References ... 5
3 Terms and Definitions ... 6
4 General Test Requirements ... 7
4.1 Accuracy of Measurement Equipment ... 7
4.2 General Test Conditions ... 7
5 Electrical Test ... 9
5.1 General Charge Conditions ... 9
5.2 Capacity ... 10
5.3 Adjustment of State of Charge (SoC) ... 10
6 Safety Test ... 10
6.1 General Requirements ... 11
6.2 Mechanical Test ... 11
6.3 Temperature Test ... 13
6.4 Electrical Test ... 15
Nickel-metal Hydride Cells and Modules Used for Electric
Road Vehicles - Safety Requirements
1 Scope
This document specifies the testing and acceptance of the safety performance of nickel-metal
hydride (Ni-MH) cells and modules used for electric road vehicles (EV). Electric road vehicles
(EV) include battery electric vehicles (BEV) and hybrid electric vehicles (HEV).
This document does not apply to the safety assessment of nickel-metal hydride (Ni-MH) cells
during transportation and storage.
NOTE 1: in this document, nickel-metal hydride (Ni-MH) secondary cells refer to sealed metal
hydride nickel cells: these sealed cells use nickel hydroxide as the positive electrode and
hydrogen alloy as the negative electrode, and alkaline aqueous solution, for example,
potassium hydroxide, as the electrolyte. Sealed cells are cells that can maintain their
sealed condition and will not release gas or liquid when charged and discharged within
the temperature range specified by the cell manufacturer. These cells are equipped with
a gas release device to prevent explosion.
NOTE 2: this document is to ensure the basic safety performance of the battery system under
expected use and reasonably foreseeable misuse during the normal operation of electric
road vehicles.
NOTE 3: in this document, all descriptions of cells are applicable to module testing.
2 Normative References
The contents of the following documents constitute indispensable clauses of this document
through the normative references in the text. In terms of references with a specified date, only
versions with a specified date are applicable to this document. In terms of references without a
specified date, the latest version (including all the modifications) is applicable to this document.
GB/T 2900.41-2008 Electrotechnical Terminology - Primary and Secondary Cells and Batteries
[IEC 60050 (482):2004, IDT]
GB/T 19596-2017 Terminology of Electric Vehicles
GB 38031-2020 Electric Vehicles Traction Battery Safety Requirements
IEC 61434 Secondary Cells and Batteries Containing Alkaline or Other Non-acid Electrolytes
- Guide to Designation of Current in Alkaline Secondary Cell and Battery Standards
The percentage of the capacity of the current storage battery that can be released in accordance
with specified discharge conditions in the available capacity.
[source: GB/T 19596-2017, 3.3.3.2.5]
4 General Test Requirements
4.1 Accuracy of Measurement Equipment
4.1.1 Range of measurement devices
The instruments / devices used shall be able to accurately measure voltage and current values.
The measuring range of the instruments / devices and the measurement method selection shall
ensure the accuracy specified for each test. For analog instruments, readings shall be taken from
the later 1/3 of the dial. Any other measurement instruments of equivalent accuracy can be used.
4.1.1.2 Voltage measurement
The accuracy of the instrument used for voltage measurement shall be equal to 0.5 or higher.
The resistance of the voltmeter used shall be at least 1,000 /V.
4.1.1.3 Current measurement
The accuracy of the instrument used for current measurement shall be equal to 0.5 or higher.
The entire assembly of ammeter, shunt and leads shall have an accuracy level of 0.5 or higher.
4.1.2 Tolerances
Relative to the specified or actual value, the overall accuracy of the controlled or measured
value shall be within the following tolerance ranges:
a) Voltage  1%;
b) Current  1%;
c) Temperature  2 C;
d) Time  0.1%;
e) Dimensions  0.1%.
These tolerances include the comprehensive accuracy of the measurement instruments, the
measurement technique used and all other errors during the test process.
4.2 General Test Conditions
4.2.1 Test temperature
the following mode:
---Step 1: before charging, the cell shall be placed at ambient temperature and discharged
at a constant current of 1/3 It to the termination voltage specified by the cell
manufacturer;
---Step 2: at ambient temperature, charge the cell in accordance with the charging method
specified by the cell manufacturer.
5.2 Capacity
Before adjusting the charging status in accordance with 5.3, the rated capacity of the cell shall
be confirmed in accordance with the following steps.
---Step 1: charge the cell in accordance with the provisions of 5.1 After charging, the cell
temperature shall be stabilized in accordance with 4.2.1.
---Step 2: the cell shall be discharged at 1 It to 0.9 V at ambient temperature. The maximum
discharge current is 200 A. When testing a module, the value of the termination voltage
is the product of the termination voltage of a cell and the quantity of cells connected in
series in the module.
The test method for the current It is as defined in IEC 61434.
---Step 3: measure the discharge duration, until the termination voltage is reached;
calculate the cell capacity and retain three significant figures.
5.3 Adjustment of State of Charge (SoC)
The test cell shall be charged in accordance with the following steps. The adjustment of state
of charge is the procedure for preparing cells with different states of charge for testing.
---Step 1: charge the cell in accordance with 5.1.
---Step 2: in accordance with 4.2.1, let the cell stand at ambient temperature.
---Step 3: the cell shall be discharged at a constant current of 1/3 It at ambient temperature
for ଷ ൈሺଵ଴଴ି௡ሻଵ଴଴ h. The current SoC of the cell is n%, which needs to be adjusted for each
test.
6 Safety Test
WARNING: when selecting a test, if Scheme A is selected, only Scheme A can be selected
for other test methods; if Scheme B is selected, only Scheme B can be selected for other
test methods.
6.1 General Requirements
Safety tests shall be conducted under conditions specified by the cell manufacturer, using cells
or modules that are no more than 6 months old.
In accordance with the agreement between the cell manufacturer and customer, determine the
quantity of cells required for each test.
For all specified tests, the test installation conditions, including cell or module safety and wiring
conditions, shall be recorded.
NOTE: if necessary, in order to prevent deformation, without violating the purpose of the test, the
cells shall be maintained during the test.
6.2 Mechanical Test
6.2.1 Mechanical shock
6.2.1.1 Test purpose
This test is to verify the safety...