2012 Hyundai Sonata Hybrid doesn’t anymore have a rating of 40 mpg on the EPA test cycle but with the updates to the 2013 Hyundai Sonata Hybrid, it can now achieve 40 mpg on the highway. Hyundai still considers this hybrid as its most fuel-efficient model but it was one of several models involved in the recent MPG inflation controversy.
But with the introduction of the 2012 model, Hyundai says goodbye to its problems. The updated model is priced lower and has better fuel economy. Hyundai concentrated its efforts on three major hybrid system components: the lithium-polymer battery pack, electric motor, and hybrid starter generator. The most significant change is the battery pack. It has an output of 47 kW, an improvement over the 34 kW last year.
The pack offers more energy but it’s lighter and more compact. The battery has a weight of 87.8 pounds (a drop from 92.4) while trunk space has increased from 10.7 cubic feet to 12.1.
The extra battery capacity enabled Hyundai to boost the output of the electric motor without compromising its range or fuel economy. The motor is capable of delivering 35 kW (compared to last year’s 30 kW). Meanwhile, the hybrid starter generator (which starts the engine and synchronizes its speed to the transmission) can now deliver 10.5 kW of power, up from 8.5 kW.
As a result, Hyundai comes with smoother engine starts and extra time used in EV mode. The Sonata Hybrid is capable of reaching a speed of up to 75 mph using just the transmission-mounted electric motor. The six-speed automatic transmission and the gas engine – a variant of the Sonata’s 2.4-liter I-4 that runs on the Atkinson cycle – have been modified to make them a bit more efficient.
Sonata Hybrid is now the only Hyundai to reach the momentous 4-0 highway number. According to EPA’s estimates, this model can return 36 mpg in the city and 40 on the highway. When combined, the base Sonata Hybrids can achieve 38 mpg while top-trim Limited models have a 37 mpg rating.
There are many advantages when it comes to the standard lithium-ion batteries. They are not only easy to handle but can even withstand those mild internal pressures. Introduced in 1991, since then it has come in different forms. The implication is that the manufacturing set-up is already there with the economies scale being reasonably high. Like with most things, there are also disadvantages attached to it.
Because of the cylindrical shape, the packaging efficiency is lowered. In addition, since it utilizes a lot of small parts, the manufacturing process is complex. Further, the small parts mean they are robust when it comes to thermal fluctuations. Weight and cost of the overall battery system are increased. When it comes to a vehicle battery package, the consistency between cells is truly critical.
This is because the entire package is just as strong as the weakest cell. Indeed, standard lithium-ion batteries have substantial cell-to-cell variation. This is where the lithium polymer batteries of Hyundai have an edge as the cell-to-cell consistency is exceptional. In addition to lower manufacturing costs, lithium-polymer batteries have higher energy intensity compared to the lithium-ion versions.
Further, the polymer variant has more resistance when it comes to physical damage. It can even manage extra charge-discharge cycles even before that batteries’ storage capacity starts to degrade. Lithium polymer technology also comes with substantial benefits as it relates to safety and thermal robustness. Another main difference with the standard lithium-ion batteries and the lithium polymer battery solution offered by Hyundai is the cell’s overall packaging, that is, the cathode, electrolyte, anode, and encasement material.
For those not familiar, the usual lithium-ion batteries come in what is known as 17650 cell format and generally seen in laptops. For this configuration, the cells are mass produced with each one having a diameter of 18 mm and measure 65 mm tall. For comparison, this means it is slightly larger compared to an “AA” battery. Further, each of the small metal cylinders has a liquid electrolyte filled to it. This helps the lithium ions move from the anode and to the cathode, resulting in a battery current.