GB/T 44649-2024 PDF English
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Nickel-metal hydride cells and modules used for electric road vehicles - Safety requirements
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GB/T 44649-2024: PDF in English (GBT 44649-2024) 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 ൈሺଵିሻଵ 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 performance of the cell under inertial loads that may occur in a
vehicle collision.
6.2.1.2 Test steps
The test shall be carried out in accordance with the following steps:
---Step 1: in accordance with 5.3, adjust the SoC of the cell for BEV to 100%, and adjust
the SoC of the cell for HEV to 80%.
---Step 2: the cell shall be fixed onto the testing machine through rigid structural support.
This support will support all surfaces of the cell.
---Step 3: apply a half-sine impact with a peak acceleration of 50 gn (gn represents the
standard gravity acceleration, which is 9.80665 m/s2) and a pulse duration of 11 ms to
the cell. In three mutually perpendicular installation positions, the cell shall respectively
withstand 3 impacts in the positive direction, then, respectively 3 impacts in the
negative direction, for a total of 18 impacts.
6.2.1.3 Acceptance indicator
During the test, the cell shall not manifest signs of fire or explosion.
6.2.2 Extrusion
6.2.2.1 Test purpose
This test is used to measure the cell’s response to external load forces that may cause
deformation.
This test is to simulate the high-temperature environment that the cell will experience during
normal vehicle operation and to verify the safety performance of the cell under such conditions.
6.3.1.2 Test steps
Scheme A: the test shall be carried out in accordance with the following steps.
---Step 1: in accordance with 5.3, adjust the SoC of the cell for BEV to 100%, and adjust
the SoC of the cell for HEV to 80%.
---Step 2: the cell shall be placed in a box with circulating air. The temperature inside the
box is 60 C 2 C, and the cell shall be maintained at this temperature for 2 hours.
Then, lower the temperature to 25 C 2 C and observe the cell in the box for 1 hour.
NOTE: if necessary, in order to prevent deformation, without violating the purpose of the test, the
cells shall be maintained during the test.
Scheme B: the test steps shall comply with GB 38031-2020.
6.3.1.3 Acceptance indicator
During the test, the cell shall not manifest signs of fire or explosion.
6.3.2 Temperature cycle
6.3.2.1 Test purpose
This test is to simulate alternative high and low temperature environments that may cause
expansion and contraction of battery packs and verify the safety performance of the cell under
such conditions.
6.3.2.2 Test steps
Scheme A:
The test steps are as follows.
---Step 1: in accordance with 5.3, adjust the SoC of the cell for BEV to 100%, and adjust
the SoC of the cell for HEV to 80%.
---Step 2: all protective devices that may affect cell performance and test results shall be
normally used.
---Step 3: unless the cell manufacturer requires a higher temperature, the cell shall be
stored at 60 C 2 C for at least 6 hours. Then, unless the cell manufacturer requires
a higher temperature, the cell shall be stored at 40 C 2 C or lower for at least 6
hours. The maximum time interval between these two extreme temperature tests is 30
minutes. This step shall be repeated, until at least 5 cycles are completed, after which,
the cell shall be stored at room temperature for 24 hours.
---Step 4: after completing the above-mentioned test steps, observe the cell at ambient
temperature for 1 hour.
Scheme B:
The test steps shall comply with GB 38031-2020.
6.3.2.3 Acceptance indicator
During the test, the cell shall not manifest signs of fire or explosion.
6.4 Electrical Test
6.4.1 External short-circuit current
6.4.1.1 Test purpose
This test is to verify the safety performance of the cell when exposed to external short circuit.
6.4.1.2 Test steps
Scheme A:
The test steps are as follows.
---Step 1: the cell shall be fully charged in accordance with 5.1.
---Step 2: the positive and negative terminals of the cell shall be connected through an
external resistor for 10 minutes for short-circuit test. The total external resistance of
each cell shall be not greater than 5 m and may also be specified by the customer and
cell manufacturer.
---Step 3: after completing the above-mentioned test steps, observe the cell at ambient
temperature for 1 hour.
Scheme B:
The test steps shall comply with GB 38031-2020.
6.4.1.3 Acceptance indicator
During the test, the cell shall not manifest signs of fire or explosion.
6.4.2 Overcharge
6.4.2.1 Test purpose
This test is to verify the safety performance of the cell under overcharge conditions.
6.4.2.2 Test steps
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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