Modeling and Validation of 12V Lead-Acid Battery for Stop-Start Technology

Abstract

As part of the Midterm Evaluation of the 2017-2025 Light-duty Vehicle Greenhouse Gas Standards, the U.S. Environmental Protection Agency (EPA) developed simulation models for studying the effectiveness of stop-start technology for reducing CO 2 emissions from light-duty vehicles. Stop-start technology is widespread in Europe due to high fuel prices and due to stringent EU CO2 emissions standards beginning in 2012. Stop-start has recently appeared as a standard equipment option on high-volume vehicles like the Chevrolet Malibu, Ford Fusion, Chrysler 200, Jeep Cherokee, and Ram 1500 truck. EPA has included stop-start technology in its assessment of CO 2-reducing technologies available for compliance with the standards. Simulation and modeling of this technology requires a suitable model of the battery. The introduction of stop-start has stimulated development of 12-volt battery systems capable of providing the enhanced performance and cycle life durability that it requires. Much of this activity has involved advanced lithium-ion chemistries, variations of lead-acid chemistries, such as absorbed-glass-mat (AGM) designs, and lead-carbon formulations. EPA tested several AGM batteries that are used in OEM start-stop systems. The purpose of this testing was to develop an equivalent circuit model for integration into EPA's ALPHA vehicle simulation model. Testing was performed at the Battery Test Facility (BTF) at the U.S. Environmental Protection Agency (EPA) National Vehicle and Fuel Emissions Laboratory (NVFEL) in Ann Arbor, Michigan. The Duracell batteries referenced are model number SLI49AGM with a rating of 92 Ah and the X2 Power batteries referenced are model number SLI34-78AGMDP with a rating of 68 Ah. Both batteries are 6 cell 12 volt using AGM technology. For compatibility with the voltage specifications of the BTF equipment, tests were performed on two batteries connected in series (nominal 24 volts). This paper presents the development and validation of the lead-acid battery model. The battery model is a standard equivalent circuit model with two Resistance-Capacitance (RC) blocks. Resistances and capacitances were calculated using test data from a Duracell 92Ah lead-acid battery which is aftermarket equipment for the Chevrolet Malibu. The lead-acid battery library in the ALPHA model was validated with data obtained from Argonne National Laboratory (ANL) from their chassis dynamometer testing of the 2010 Mazda 3 Hatchback i-Stop [9] and 2010 VW Golf TDI Diesel Bluemotion [10]. The simulated battery voltages, currents, and state of charge (SOC) are in excellent agreement with the vehicle test data on a number of drive schedules.

Eco-driving technology for sustainable road transport: A review

“…New engine technologies can also help reduce idling in traffic. For example, many new vehicles are now equipped with stop-start technology which turns off the engine whenever idling and restarts comfortably when drivers touch the accelerator pedal [65,66]. Fonseca et al [67] reported that a vehicle with a stop-start system had more than 20% CO2 reduction than a similar vehicle without stop-start technology, partly due to zero idling emissions.…”

Active Charge Balancing Strategy Using the State of Charge Estimation Technique for a PV-Battery Hybrid System

“…Active battery balancing strategy accompanied by BMS for PV-Battery integrated system are conveyed together in the MATLAB-Arduino interfacing experience. Four series-connected lead-acid batteries are employed in this paper to validate the proposed battery balancing methodology for which the relationship between OCV vs. SOC is as shown in Figure 13 [35].…”

Description of acid battery operating parameters

“…For this purpose, the equation ( 9) was decoded in order to determine the coefficients describing the quantitative influence of individual physical variables on the value of the loaded battery voltage. The decoded linear model of the tested object is a quantitative model, which describes the dependence of the loaded battery terminal voltage U as a variable depending on the nominal (rated) capacity Q, the discharge current I, ambient (electrolyte) temperature T and the (technical) state of charge (SOC) k as independent variablesis presented as the expression (10). It makes it possible to know the "degree of influence" of individual independent variables on the dependent variable.…”

“…charging/discharging voltage and the state of charge (SOC) [2]. Very often lead-acid battery model for Stop-Start Technology is a circuit model with two resistance-capacitance (RC) blocks [10]. The simulated battery operating parameters are voltages, currents, and state of charge.…”