What do the time (s) and speed (mph) curves of the dynamic stress test (DST) for automotive operatin

subject : Lithium battery for electric vehicle

Ans 

Dynamic stress test (DST) :-

• The dynamic stress test (DST) for Lithium batteries in electric vehicle operating conditions is a critical evaluation to assess the battery's performance, safety, and durability.

• The dynamic stress test (DST) for lithium-ion batteries for electric vehicle (EV) operating conditions is a standardized test that simulates the real-world driving conditions that an EV battery would experience. 

• The test consists of a series of constant power steps, with each step representing a different driving condition, such as acceleration, deceleration, and cruising.

• The specific time and speed curves for the DST can vary depending on the testing standards and the objectives of the test.

• The time and speed profiles of the DST vary depending on the specific test profile used. 

In a typical DST, the time (s) and speed (mph) curves :-

(i) Time (s) Curve:- 

• The time curve typically represents the duration of the test, which can vary depending on the standards or specifications. 

• The test may include different phases such as charge, discharge, thermal cycling, or other relevant operations. 

• The time curve will show how long each phase of the test lasts.

(ii) Speed (mph) Curve:- 

• The speed curve is not a common parameter in battery testing, but it may be relevant in cases where the vehicle's speed affects the battery's thermal performance. 

• For instance, testing the battery's response to rapid acceleration or deceleration.

In a typical DST, the time (s) and speed (mph) curves includes the following elements:-

(i) Charge/Discharge Cycles:- 

• The test involves a series of charge and discharge cycles, typically at different rates. 

• This may include continuous charge and discharge, pulse cycles, and rest periods.

(ii) Temperature Variations:- 

• The battery is subjected to different temperature conditions, including both extreme high and low temperatures, to evaluate its thermal performance.

(iii) Voltage and Current Profiles:- 

• The voltage and current waveforms represent the electrical stress on the battery. 

• This includes fast charging, fast discharging, regenerative braking, and more.

(iv) Cycling Speeds:- 

• The speed (in mph) of the electric vehicle may vary during the test. 

• This simulates real-world driving conditions, which include both acceleration and deceleration.

(v) Environmental Conditions:-

• The battery may also be exposed to environmental stress factors, such as humidity, altitude, and thermal shock, depending on the test protocol.

DST (Dynamic stress test ) profile consist of the following:-

• Acceleration step: The battery is discharged at a high power rate for a short period of time, simulating the acceleration of the EV.

• Deceleration step: The battery is charged at a high power rate for a short period of time, simulating the deceleration of the EV.

• Cruising step: The battery is discharged at a moderate power rate for a longer period of time, simulating the cruising of the EV.

International standards and guidelines for lithium battery testing are provided by organizations :-

(i) IEC (International Electrotechnical Commission):-

• IEC 62660 series provides standards for lithium-ion traction batteries used in electric vehicles.

(a) IEC 62660:- 

• This is an international standard that provides guidelines for testing lithium-ion batteries used in electric vehicles. 

• It covers various aspects of battery testing, including electrical, thermal, and mechanical aspects.

(b) IEC 62660-2:- 

• This standard from the International Electrotechnical Commission (IEC) specifies test procedures for lithium-ion traction battery packs used in electric vehicles.

•  It includes mechanical and electrical testing procedures.

(c) IEC 62619:- 

• This standard specifies requirements and test procedures for lithium-ion batteries used in electric vehicles. 

• It covers various performance and safety aspects.

(ii) SAE International (Society of Automotive Engineers):- 

• SAE J2464, SAE J2929, and other standards from SAE provide guidelines for testing and safety of electric vehicle batteries.

(a) SAE J2464:- 

• The Society of Automotive Engineers (SAE) has published standards related to electric vehicle battery testing. 

• SAE J2464 focuses on lithium-ion battery performance testing and characterization.

(iii) ISO (International Organization for Standardization):- 

• ISO 12405 series includes standards for lithium-ion batteries in electric road vehicles.

(a) ISO 12405:-

• ISO (International Organization for Standardization) standards also provide guidelines for testing lithium-ion batteries for electric vehicles.

•  ISO 12405 addresses various test procedures and conditions.

(b) ISO 12405-1:- 

• Part of the ISO 12405 series, this standard provides guidelines for testing lithium-ion cells in various conditions, including electrical, thermal, and mechanical tests.

(iv) UN ECE (United Nations Economic Commission for Europe):- 

• UN Regulation No. 100 covers the approval of electric powertrains for electric vehicles and their components, including batteries.

(a) UN 38.3:- 

• The United Nations Manual of Tests and Criteria for the Transport of Dangerous Goods outlines various tests for lithium batteries, including mechanical testing, environmental testing, and electrical testing.

Explanation:

Dynamic stress test (DST) :-

• The test consists of a series of constant power steps, with each step representing a different driving condition, such as acceleration, deceleration, and cruising.

• The time and speed profiles of the DST vary depending on the specific test profile used. 

International standards and guidelines for lithium battery testing are provided by organizations :-

(i) IEC (International Electrotechnical Commission):-

• IEC 62660 series provides standards for lithium-ion traction batteries used in electric vehicles.

(a) IEC 62660:- 

• This is an international standard that provides guidelines for testing lithium-ion batteries used in electric vehicles.

• It covers various aspects of battery testing, including electrical, thermal, and mechanical aspects.

(ii) SAE International (Society of Automotive Engineers):- 

• SAE J2464, SAE J2929, and other standards from SAE provide guidelines for testing and safety of electric vehicle batteries.

(a) SAE J2464:- 

• The Society of Automotive Engineers (SAE) has published standards related to electric vehicle battery testing.

• SAE J2464 focuses on lithium-ion battery performance testing and characterization.

(iii) ISO (International Organization for Standardization):- 

• ISO 12405 series includes standards for lithium-ion batteries in electric road vehicles.

(a) ISO 12405:-

• ISO (International Organization for Standardization) standards also provide guidelines for testing lithium-ion batteries for electric vehicles.

• ISO 12405 addresses various test procedures and conditions.

(iv) UN ECE (United Nations Economic Commission for Europe):- 

• UN Regulation No. 100 covers the approval of electric powertrains for electric vehicles and their components, including batteries.

(a) UN 38.3:- 

• The United Nations Manual of Tests and Criteria for the Transport of Dangerous Goods outlines various tests for lithium batteries, including mechanical testing, environmental testing, and electrical testing.