Battery product standards, especially safety standards, are not only an important basis for restricting quality, but also an important means to standardize market order and promote technological progress. This paper introduces, summarizes and analyzes the existing common standards, and briefly discusses the problems existing in these standard systems.
Common power lithium ion battery standards
- international standards
Important power lithium ion battery standards published by IEC include IEC62660-1:2010 lithium ion power battery monomer for electric road vehicles Part 1: performance test and IEC62660-2:2010 lithium ion power battery monomer for electric road vehicles Part 2: reliability and abuse test. UN 38.3 “United Nations recommendations, standards and test manual on the transport of dangerous goods” issued by the United Nations Transport Committee, the requirements for the test of lithium-ion batteries are aimed at the safety of batteries during transportation.
ISO’s standards for power lithium-ion batteries include ISO12405-1:2011 electric drive vehicles – Test procedures for lithium-ion power lithium battery packs and systems Part 1: high power applications, ISO12405-2:2012 electric drive vehicles – Test procedures for lithium-ion power lithium battery packs and systems Part 2: high energy applications, and ISO12405-3:2014 Electrically driven vehicles – Test procedures for lithium ion power lithium battery packs and systems – Part 3: Safety requirements, which are respectively aimed at high-power batteries, high-energy batteries and safety performance requirements, in order to provide optional test items and test methods for the whole vehicle factory.
- American Standard
UL2580:2011 battery for electric vehicles mainly evaluates the reliability of battery abuse and the ability to protect personnel in case of abuse. The standard was revised in 2013.
SAE has a huge and perfect standard system in the automotive field. SAEJ2464:2009 safety and abuse test of rechargeable energy storage system of electric and hybrid electric vehicles issued in 2009 It is an early batch of vehicle battery abuse test manuals applied in North America and the world, which clearly points out the scope of application of each test item and the data to be collected, and also gives suggestions on the number of samples required for the test project.
SAEJ2929:2011 safety standard for electric and hybrid lithium battery system issued in 2011 is a safety standard proposed by SAE on summarizing various power lithium battery related standards issued before, including two parts: routine test and abnormal test that may occur during driving of electric vehicles.
SAEJ2380:2013 vibration test of electric vehicle battery is a classic standard for vibration test of electric vehicle battery. Based on the statistical results of vibration load spectrum collection of actual vehicle driving on the road, the test method is more in line with the vibration situation of actual vehicle and has important reference value.
- other organization standards
The U.S. Department of energy (DOE) is mainly responsible for energy policy formulation, energy industry management and energy related technology research and development. In 2002, the U.S. government established the “FreedomCAR” project, and successively issued the FreedomCAR power assisted hybrid electric vehicle battery test manual and the abuse test manual of energy storage system for electric and hybrid electric vehicles.
The German automobile industry association (VDA) is mainly responsible for various standards of the same German automobile industry.The standards issued include VDA2007 battery system test for hybrid electric vehicles, which is mainly aimed at the performance and reliability test of lithium-ion battery system for hybrid electric vehicles.
Economic Commission for Europe (ECE) R100.2 uniform provisions on the approval of vehicles with regard to special requirements for electric vehicles It is the specific requirements formulated by ECE for electric vehicles, which is divided into two parts: the first part standardizes the motor protection, rechargeable energy storage system, functional safety and hydrogen emission of the whole vehicle, and the second part is the new specific requirements for the safety and reliability of rechargeable energy storage system.
Standard analysis of power lithium ion battery
- Scope of application
IEC62660 series is aimed at the test of battery unit and module level, while UL2580, SAEJ2929 and ISO12405 series are applicable to the test of battery pack and battery system. In addition to IEC62660, other standards basically involve battery pack or system level testing. SAEJ2929 and ECER100.2 even mention vehicle level testing. This shows that the formulation of international standards takes more account of the application of batteries in the whole vehicle, which is more in line with the needs of practical applications.
- Test item content
On the whole, all test items can be divided into two categories: electrical performance and safety reliability, and safety reliability can be divided into mechanical reliability, environmental reliability, abuse reliability and electrical reliability.
Mechanical reliability, which simulates the mechanical stress of the vehicle during driving, such as vibration, and simulates the bumpiness of the vehicle on the road; Environmental reliability, which simulates the tolerance of the vehicle in different climates. For example, the temperature cycle simulates the situation of the vehicle when the temperature difference between day and night is large or driving back and forth in cold and hot areas; Abuse reliability, such as fire, to investigate the safety of the battery in case of improper use; For electrical reliability, such as protection test items, it is important to investigate whether the battery management system (BMS) can play a protective role at a critical time.
In terms of battery cells, IEC62660 is divided into two independent standards IEC62660-1 and IEC62660-2, corresponding to performance and reliability tests respectively.
In terms of battery pack and battery system testing, American standards cover the most test items in terms of electrical performance and reliability. In terms of performance test, DOE / id-11069 has more test items than other standards, such as hybrid pulse power characteristic (HPPC), operation set point stability, calendar life, reference performance, impedance spectrum, module control inspection test, thermal management load and system level test combined with life verification.
The analysis method of electrical performance test results is introduced in detail in the appendix of the standard. Among them, HPPC test can be used to detect the peak power of power lithium battery. The derived DC internal resistance test method has been widely used to study the internal resistance characteristics of battery. In terms of reliability, UL2580 has more test items than other standards: unbalanced battery pack charging, withstand voltage, insulation, continuity test and cooling / heating stability system fault test. It also includes the basic safety test for battery pack parts on the production line. In terms of BMS, cooling system and protection circuit design, the safety review requirements are strengthened. SAEJ2929 proposes to conduct fault analysis on each part of the battery system and save relevant documents, including improvement measures that are easy to identify faults.
ISO12405 series standards include both battery performance and safety. ISO12405-1 is a battery performance test standard for high-power applications, and ISO12405-2 is a battery performance test standard for high-energy applications. The former includes cold start and hot start.
Different from other standards, SAEJ2929 and ECER100.2 both involve high voltage protection requirements and belong to the safety category of electric vehicles.
- Severity
For the same test item, different standards have similarities and differences.For example, with regard to the state of charge (SOC) of the test sample, ISO12405 requires that the SOC of power battery is 50% and that of energy battery is 100%; ECER100.2 requires the SOC of the battery to be more than 50%; UN38.3 there are different requirements for different test items, and some test items need recycled batteries.
In addition, high simulation, thermal test, vibration, impact and external short circuit must be tested with the same sample, which is more strict. For vibration test, ISO12405 requires samples to vibrate at different ambient temperatures. The recommended high temperature and low temperature are 75 ℃ and – 40 ℃ respectively.
As for the fire test, the experimental method and parameter setting in ISO12405.3 are preheating, direct fire and indirect fire by igniting the fuel. There is no time for the flame to extinguish. The fire test in SAEJ2929 is different from the former. It requires that the sample be placed in a thermal radiation container, rapidly raise the temperature to 890 ℃ within 90s and keep it for 10min, And no component or substance shall pass through the metal mesh placed outside the test sample.