GB 29743.2-2025Motor vehicle coolant - Part 2: Electric vehicle coolant (English PDF)

1 Scope

GB 29743.2-2025 is the Chinese national standard on motor vehicle coolant - part 2: electric vehicle coolant, in the field of services and company organization. It carries no /T suffix, which in the Chinese system means compliance is mandatory: a product or a practice within its scope has to meet it to be lawfully made, sold or carried out in China. It was issued on 28 March 2025 by the State Administration for Market Regulation; Standardization Administration of China, and has been in force since 1 October 2025. Classification: ICS 03.220.20, CCS R16. This page is published from the official record of the standard held by the Chinese standards administration: the identification, the dates, the classification and the issuing body are taken from there. The clause text, the tables and the numeric limits are in the document itself, which is delivered complete in English translation.

This document specifies the product classification, technical requirements and test methods, inspection rules, as well as marking, packaging, transportation and storage of electric vehicle coolants. This document is applicable to the production, inspection and use of electric vehicle coolants prepared with ethylene glycol as the antifreeze raw material in the power battery thermal management system of pure electric vehicles, fuel cell electric vehicles and hybrid electric vehicles with independent thermal management circuits and Class B voltage circuits.

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 528-2009 Rubber, Vulcanized or Thermoplastic - Determination of Tensile Stress-strain Properties

GB/T 711 Hot-rolled Quality Carbon Structural Steel Plates, Sheets and Wide Strips

GB/T 1173-2013 Casting Aluminum Alloy

GB/T 1690 Rubber, Vulcanized or Thermoplastic - Determination of the Effect of Liquids

GB/T 3190 Chemical Composition of Wrought Aluminum and Aluminum Alloys

GB/T 5231 Designation and Chemical Composition of Wrought Copper and Copper Alloys

GB/T 6031-2017 Rubber, Vulcanized or Thermoplastic - Determination of Hardness (hardness between 10 IRHD and 100 IRHD)

GB/T 6682-2008 Water for Analytical Laboratory Use - Specification and Test Methods

GB/T 14832-2008 Test Methods for Compatibility between Hydraulic Fluids and Standard Elastomeric Materials

GB/T 19596 Terminology of Electric Vehicles

GB 29743.1-2022 Motor Vehicle Coolant - Part

3 Terms and Definitions

The terms and definitions defined in GB/T 19596, and the following are applicable to this document.

6.2.2 The exit-factory batch inspection items include appearance, color, odor, density, boiling point, freezing point, pH, conductivity, reserve alkalinity and foam tendency.

6.2.3 The exit-factory periodic inspection items include the items in 6.2.2, as well as ash content, chlorine content, sulfate content, effect on vehicle organic finishes, water content, static corrosion and high-temperature stability.

6.3 Batch Under the condition that raw materials and processes remain unchanged, each produced pot or multiple continuously produced pots of products evenly mixed are considered an inspection batch.

6.4 Sampling Sampling shall be carried out in accordance with the provisions of SH/T 0065.The sampling size of each batch of products shall meet the requirements of inspection and sample retention, or samples can be randomly selected from the packaged products for inspection and retention.

6.5 Determination Rules When the exit-factory inspection results comply with the requirements of Chapter 5, the batch of products is determined as qualified. When the type inspection results comply with the requirements of Chapter 5, the batch of products is determined as qualified in the type inspection.

6.6 Re-inspection Rules If the results of exit-factory inspection and type inspection do not meet the requirements of Chapter 5, a double size of samples shall be re-taken from the same batch of products, and the disqualified items shall be re-inspected. If the re-inspection results meet the requirements, then, determine in accordance with 6.5; if the re-inspection results still do not meet the requirements, then, determine it as disqualified.

7 Marking, Packaging, Transportation and Storage

7.1 The vehicle coolants shall be marked and packaged in accordance with the provisions of NB/SH/T 0164.The marking content shall include.

a) Product name;

b) Antifreeze type;

c) Product classification and freezing point;

d) How to use the concentrate product (see Appendix E for the specifications of dilution water);

Appendix A

(normative) Test Method for the Conductivity of Vehicle Coolants A.1 Principle Measure-take 100 mL of the vehicle coolant specimen and use a conductivity meter to measure its conductivity. A.2 Instruments and Materials A.2.1 Conductivity meter. with an accuracy class of

0.5 and automatic temperature compensation function. In accordance with the conductivity range of the vehicle coolant, select the appropriate conductivity electrode. A.2.2 Measuring cylinder. with a capacity of 100 mL. A.2.3 Conical flask. with a capacity of 100 mL and a stopper. A.2.4 Constant temperature water bath. capable of controlling the temperature at 25 C 0.2 C. A.3 Test Steps A.3.1 In accordance with the requirements in the instructions for use of the conductivity meter, select the conductivity calibration solution with a suitable measurement interval to calibrate the conductivity meter and electrode. A.3.2 Use a measuring cylinder to measure-take 100 mL of the vehicle coolant specimen and pour it into a conical flask. Place it in a water bath that has been kept at a constant temperature of 25 C 0.2 °C for 20 minutes. A.3.3 Immerse the electrode in the specimen to determine the conductivity. Repeat the determination twice, and meanwhile, record the specimen temperature. A.3.4 When measuring specimens with a conductivity less than 3 S/cm, it is advisable to use a conductivity meter equipped with a sealed flow cell and measure in a flowing state. A.4 Result Report Report the arithmetic mean of the two repeated determinations as the test result, accurate to 0.1 S/cm.

Appendix B

(normative) Test Method for the Static Corrosion of Vehicle Coolants B.1 Principle Prepare the typical metals used for the vehicle cooling system into test pieces, which are then grinded, cleaned and weighed, and assembled into a test piece bundle in a specified sequence. Place it in a test cup, pour in 750 mL of the vehicle coolant specimen, transfer it to the heating equipment, and under the conditions of test temperature 80 C 2 C and air flow rate 100 mL/min 10 mL/min, maintain it for 336 h 2 h. After the test, as required, respectively inspect the changes in the mass of the metal test pieces and the performance of the vehicle coolant. B.2 Instruments and Materials B.2.1 Instruments B.2.1.1 Test cup. 1,000 mL, tall, without spout, made of heat-resistant glass. Equipped with a rubber plug, with through holes for installing condenser, gas diffusion tube and thermometer. The assembly of the test components is shown in Figure B.1. B.2.1.2 Condenser. the condenser jacket is 400 mm long and is a straight-type reflux condensing tube. B.2.1.3 Gas diffusion tube. made of heat-resistant glass, with a tube length of 220 mm and an outer diameter of 8 mm, and a sand core glass diffusion head with a length of 30 mm and an outer diameter of 15 mm at the end. B.2.1.4 Thermometer. 20 C ~ 150 C, with a division value of 1 C, or an instrument with the same accuracy. B.2.1.5 Heating equipment. liquid bath heating, capable of controlling the temperature at 80 °C 2 °C, or an instrument with the same accuracy. B.2.1.6 Air flow meter. capable of controlling the air flow rate at 100 mL/min 10 mL/min. B.2.1.7 Balance. with a division value of

0.1 mg, and a maximum weighing not less than 200 g. B.2.2 Materials B.2.2.1 Metal test pieces. shall comply with the provisions of Table B.1. 2

---insulating washer; 8

---4043 aluminum test piece; 3

---T2 red copper test piece; 9

---6063 aluminum test piece; 4

---H70 brass test piece; 10

---brass bolt; 5

---20 steel test piece; 11

---steel washer; 6

---ZL101A cast aluminum test piece; 12

---brass washer. Figure B.2 -- Assembly of Test Piece Bundle B.4.2 Sample preparation The vehicle coolant specimen is prepared with water into a test solution with an antifreeze concentration (volume fraction) of 33%. 99 mg of sodium sulfate, 110 mg of sodium chloride and 92 mg of sodium bicarbonate are added to each liter of the test solution. B.5 Test Steps B.5.1 Clean and dry the test cup, rubber stopper, thermometer, gas diffusion tube and condenser used in the test. B.5.2 Respectively place the three assembled metal test piece bundles into three test cups, then, respectively pour 750 mL of vehicle coolant test solution into each test cup. As shown in Figure B.1, assemble the rubber stopper, thermometer, gas diffusion tube and condenser. The end of the condenser tube shall just come out of the rubber stopper. The diffusion head of the gas diffusion tube shall be at least

12.7 mm away from the test piece bundle, and the two shall not be in direct contact. B.5.3 Place the test cup on the heating equipment and properly connect the condensation water and gas circuits. The vehicle coolant is continuously tested at 80 C 2 C and an air flow rate of 100 mL/min 10 mL/min for 336 h 2 h. During the test, the test conditions shall be checked every day to ensure that the test temperature, air flow rate and liquid level meet the requirements, and the specimen shall be replenished with water in time due to evaporation loss. B.5.4 After the test is completed, remove the test cups and cool them to room temperature. Take out the metal test piece bundles and disassemble them. Use a soft bristle brush to gently scrub each test piece under tap water, so as to remove loose corrosion products attached to the surface. Each test piece shall also undergo the following cleaning treatment.

a) Red copper and brass test pieces. in a fume hood, immerse the test pieces in 100 mL of hydrochloric acid aqueous solution prepared at a volume ratio of hydrochloric acid to water of

Appendix D

(normative) Test Method for the Compatibility between Vehicle Coolants and Rubber Materials D.1 Principle Immerse the rubber sheet in the vehicle coolant and keep it at 80 C 2 C for 168 h 2 h. Inspect the volume change, hardness change, and tensile property change of the rubber sheet. D.2 Instruments, Materials and Reagents D.2.1 Test cup. made of heat-resistant glass, with an inner diameter of 70 mm 2 mm, a height of 90 mm 2 mm, and a volume of 350 mL 10 mL, equipped with a tinplate cover. D.2.2 Oven. capable of controlling the temperature at 80 C 2 C. D.2.3 Thermometer. 20 C ~ 150 C, with a division value of 1 C. D.2.4 Rubber hardness tester. shall comply with the requirements of Method M specified in GB/T 6031-2017. D.2.5 Balance. with a division value of

0.1 mg and a maximum weighing not less than 200 g. D.2.6 Tensile testing machine. with an accuracy class of

0.5 and a maximum tensile force not less than 500 N. D.2.7 EPDM rubber test pieces. the material shall comply with the requirements for EPDM rubber specified in GB/T 14832-2008, and the thickness of the test pieces shall be

0.2 mm. The rubber sheet used for mass, volume and hardness tests is a square test piece of 25 mm 25 mm. The rubber sheet used for the tensile properties test is a Type 2 dumbbell-shaped test piece that complies with the provisions of GB/T 528-2009. D.2.8 Silicone rubber test pieces. the material shall comply with the VMQ 50-G category requirements specified in GB/T 33402-2016, and the test piece thickness shall be

0.2 mm. The rubber sheet used for mass, volume and hardness tests is a square test piece of 25 mm 25 mm. The rubber sheet used for the tensile properties test is a Type 2 dumbbell-shaped test piece that complies with the provisions of GB/T 528-2009. D.2.9 Anhydrous ethanol. analytically pure. D.3 Test Steps D.3.1 Raise the oven temperature and control it at 80 C 2 C. At the same time, select 4 test cups, clean and dry them. D.3.2 For each type of rubber, respectively select 3 square test pieces and 6 dumbbell-shaped test pieces, mark them, use ethanol to clean them, use filter paper to dry them, use silk cloth to wipe them and blow them dry. D.3.3 The square test pieces are respectively measured as follows in accordance with the method of GB/T 1690.

a) Mass measurement. weigh the mass m1 of the test pieces before the test, then, weigh the mass m2 in water, accurate to

0.1 mg;

b) Hardness measurement. at 3 different points on the test pieces, measure the hardness values. The measurement points shall be dispersed and the distance between two points shall be at least 6 mm. D.3.4 Select 3 dumbbell-shaped test pieces, and in accordance with the method in GB/T 528 use a tensile testing machine to respectively measure the tensile strength and elongation at break as the pre-test data. D.3.5 Respectively place 3 square test pieces of each type of rubber and another 3 dumbbell- shaped test pieces in 2 test cups. Respectively pour 300 mL of the vehicle coolant into each cup. The test pieces shall be dispersed in the test cups without overlapping. Cover the cups with lids and place them in an oven at a constant temperature of 80 C 2 C for 168 h 2 h. D.3.6 After the test, take out the test cups and cool them to room temperature. Then, take out the rubber test pieces, use ethanol to clean them, use filter paper to dry them, use silk cloth to wipe them and blow them dry. D.3.7 Respectively measure the mass m3 of the square test pieces after the test, then, weigh the mass m4 in water to an accuracy of

0.1 mg, and measure the hardness after the test. D.3.8 The tensile strength and elongation at break of the dumbbell-shaped test pieces are respectively measured using a tensile testing machine. D.4 Result Calculation D.4.1 The volume change rate of the rubber test pieces is calculated in accordance with Formula (D.1). Where, V

---the volume change rate of rubber test pieces; m1

---the mass of the rubber test pieces before the test, expressed in (g); m2