Lithium ion car battery--Application of lithium ion battery in car

Four types of lithium ion car battery application

Lithium ion car battery–Lithium ion battery applications in the field of motor vehicles mainly fall into four types: ① Micro-hybrid electric vehicles (uHEVs); ② Hybrid electric vehicles (HEVs); ③Plug-in hybrid electric vehicles (PHEVs);④Pure electric vehicles, including extended-range electric vehicles or fuel cell electric vehicles.

Microhybrid electric vehicles

Hybrid electric vehicles

Sales of microhybrids have grown significantly in recent years due to carbon dioxide reduction and fuel economy standards, with more than 50% of new cars in Europe having technology related to microhybrids.Microhybrid electric vehicles are basically external 12V and 48V systems. Most 12V systems are based on lead-acid batteries, but are gradually moving towards lithium ion car battery, with most steam designs at 250Wh. In these applications, where the battery has no function other than stopping and starting the 48-v lithium ion car battery system can have more functions, mostly at 500wh and 1000Wh.

The difference between the 48-v and 12v lithium ion battery systems is that The 48V microhybrid electric vehicle has the energy needed to capture regenerative braking, provide power, and provide air conditioning compressors and auxiliary systems.

There are no systematic standards for microhybrids, with designers designing lithium ion car battery packs based on vehicle characteristics or lead-acid battery size. Johnson Controls uses off-the-shelf standard 48 V batteries as start-stop batteries for cars. The company has not yet released data on the battery system for its cars, but based on the cell process, it is speculated that 13 cells in series and in parallel are either PL6P or PL27P, with energies of 288 Wh (48.1V&6Ah) and 1.3 kWh (48.1V&27Ah).

Mercedes series Mercedes Benz cars use 12V system, with lead acid battery as the power supply. In Europe, similar systems are used for this series, including the B, C, CLA, CLS, E, G, GL, GLA, GLK.M, S, SLA.SLK and SLS AMG.

Plug-in hybrid electric vehicle and range extended electric vehicle

Lithium ion car battery is also widely used in hybrid electric vehicles. Hybrid electric vehicles are divided into two types: light hybrid electric vehicles and strong hybrid electric vehicles. Light hybrid electric vehicle battery voltage is low, generally 110~250 V; The battery voltage of strong hybrid electric vehicle is 330-350 V. Both hybrids used nickel-metal hydride batteries in their first generation, but are gradually moving towards lithium ion car battery.

Gm introduced the Chevrolet Malibu in 2010, powered by nickel-metal hydride batteries made by Cobasys and installed in the trunk of the car with 36 V air cooling technology. In the second generation, GE replaces the nimH battery with a lithium ion car battery, increases the system voltage to 110 V, and offers several new features, including acceleration and enhanced capture regenerative braking capabilities.

The best example of strong hybrid electric vehicle is Toyota Prius, which is the most popular and dominant hybrid electric vehicle in the current market. The Prius has been powered only by nickel-metal hydride batteries, and only the Prius plug-in hybrid uses lithium ion car battery. The Prius nickel-metal hydride battery consists of 168 6.5 Ah cells assembled into 28 modules, providing 201 V voltage and 1.3 KWH energy. Toyota’s cars use an air-cooling system that draws air into the battery pack through a built-in fan and drains it out at the other end.

The prius hybrid’s battery weighs 42kg and is mounted under the back seat. Table compares the batteries of different Prius hybrid electric vehicles.It shows how the design reduces the voltage from 288 V to 200 V by reducing the number of cells from 240 in the first-generation module to 168 in the fourth-generation module. In addition, Toyota has been replacing the cylindrical battery with square battery since the second generation, which has been maintained to this day. With the success of the technology, Toyota branded it “hybrid Co-drive”, which has now been extended to other electric vehicles and brands.

Next we’ll talk about plug-in hybrid electric vehicles. Although plug-in hybrids are generally considered a transitional form of pure electric vehicles, I personally think they are still very important. In plug-in hybrid electric vehicles, internal combustion engines and batteries are installed at the same time, and the battery energy is generally 7-16kwh. The disadvantage is that it contains two powertrains, a lithium ion car battery system and an internal combustion engine.

The basic principle of this technology is that the battery and its power system provide full electric drive of 16-64km. When the battery energy is exhausted, the internal combustion engine will start to work and continue to provide power. At this time, the plug-in hybrid electric vehicle is neither pure internal combustion engine nor pure electric vehicle, just like the traditional hybrid electric vehicle. This also improves fuel economy and provides comparable range for the fuel car.

Different lithium ion battery companies have different ideas about the battery power and range that a plug-in hybrid can drive. Some studies have concluded that about 80 percent of American drivers travel less than 64 kilometers a day to and from work, which is why plug-in hybrids have been increasing their range to less than 64 kilometers. Toyota generally provides a shorter electric drive range of about 16km; Gm’s designed electric drive range is about 64km; Ford opted for an electric range of 20km. Users can choose different car types based on average daily mileage.

Extended range electric vehicle is very similar to plug-in hybrid electric vehicle. The main difference lies in whether the two power systems are designed in parallel or in series, which will be discussed here.

Plug-in hybrid electric vehicle adopts parallel configuration, electric vehicle is directly powered by internal combustion engine or lithium ion car battery. The extended range electric vehicle is built in series. The internal combustion engine is not actually directly connected to the transmission, just as a generator is used to power the electric vehicle. When the battery is low, the engine is used to generate electricity to charge the battery and operate at the optimal speed range, and the battery provides energy to the electric motor that directly drives the vehicle. An extended-range vehicle is essentially a model of an electric car, but with an additional engine and generator.

Here are some examples of extended-range electric vehicles. The Toyota prius plug-in uses a 4.4kwh lithium ion car battery, supplied by Prime Earth Electric Vehicle, a joint venture between Toyota and panasonic, which provides a range of 16 to 24km, depending on stability, driving style and other factors. Because the battery is relatively small, it can be recharged quickly, taking only 90 minutes for a 240V charger and 3 hours for a 120V charger. The battery weighs about 80kg and is installed in the trunk. According to the environmental defense institute, the prius plug-in gets 40 kilometers per liter of gasoline and uses about 29kWh per 160 kilometers.

In the United States, Ford Motor Company has used the same lithium ion car battery technology to power a different kind of electric car. The first was the Ford C-Max Energi plug-in electric vehicle, followed by the Ford Fusion Energi, which is scheduled for release in 2012 (the third-generation Escape has been the number one SUV monthly seller in the U.S. since its launch in 2012). To keep battery prices down, Ford tried to use the same battery system as much as possible. The authors confirm this fact from meetings with the Ford team. This makes ford series of electric vehicles market share is higher, battery costs are reduced faster.

The Ford C-Max Energi and Fusion Energi plug-in hybrids are powered by panasonic’s 7.6kwh battery pack, with a range of about 32km, a range of about 37km per liter of gasoline, and a 160km consumption of about 37kWh. In the C-MAX system, the lithium ion car battery pack is mounted in the trunk, with an air cooling system and a fan as an air transport device, which is discharged from the top of the lithium ion car battery pack to the sides. The biggest challenge with Ford’s devices using exactly the same battery pack is that the battery is not assembled specifically for each vehicle, so the assembly does not necessarily match up well across all its applications.

The best example of an extended-range electric vehicle is General Motors co. ‘s Chevrolet Volt. Combined with LG chem’s 16.5KWh lithium ion car battery pack and a small internal combustion engine, the Volt has a range of about 60km, a range of about 35km per liter of gasoline, and a 160km energy consumption of about 35kWh.

The Volt’s lithium ion car battery pack is mounted on the underside of the car, in a t-shape, in the front drive shaft and fuel tank area; Liquid cooling is used to ensure that the battery can work at a proper temperature without overheating or cooling. The Volt battery pack, branded “Voltec, “consists of 288 flexible lithium ion car battery cells in four modules. Each cell is isolated by a plastic ring on one side and an aluminum radiator on the other side.

The electrode lug of the cell is connected to the top of the module in series or parallel. The Voltec battery pack has an interrupt device in the middle and can be operated from the passenger compartment. To control the temperature of the battery string, the lithium ion car battery string is wrapped with thermal insulation material.

Pure electric vehicles

At present, the most familiar brand of pure electric vehicle in the market is Tesla. The first Model is Roadster, and the second generation of Model-S passenger car is developed later. Pure electric cars differ from hybrids in that they are powered 100% by batteries and have no internal combustion engines.

In terms of battery system, Tesla is completely different from other manufacturers. Instead of trying to solve the problem of safety and reduce the complexity of battery pack from the point of view of battery cell, it adopts the standard 18650 lithium ion column cell that has been mass-produced. It is the lithium ion cell with the highest technological maturity so far, and its cost is easily accepted by consumers. But at the same time, the lithium ion car battery pack is the biggest cost factor, such as an 80kWh battery pack containing about 7,000 cells, so controlling the battery cost is extremely important.

In the Roadster, tesla’s lithium ion car battery pack uses a total of 6,831 18,650 cells. Each 69 cells are assembled into a “brick”, 9 bricks are connected in series to form a “sheet”, and 11 sheets are connected in series to form a lithium ion car battery pack.

Tesla claims it has developed a battery pack capable of preventing the spread of thermal runaway accidents, but has not disclosed the exact process. However, a number of accidents in recent years have cast doubt on the reliability of these processes. The Tesla Roadster uses a liquid cooling system to continuously control the temperature of its battery pack, which is installed in the rear seat of the car and stored in the trunk.

Tesla’s Moder-S lithium ion car battery pack is boosted to 85kWh and uses 7,104 18,650 cells. Unlike the first generation, the second generation battery pack is extremely flat. This lithium ion car battery is only 15cm high and is mounted on the bottom of the car, with a wide span from rear to front axle and left to right side of the car. The Roadster did not provide a battery source, and the Model-S uses Panasonic’s NCA18650 cell, which has two systems of 60kWh and 85kWh.

Renault-nissan introduces a variety of pure electric vehicles, the most famous and best-selling of which is the Nissan Leaf. The Leaf uses a 24kWh lithium ion car battery pack provided by Automotive Energy Supply (AESC), a joint venture between Nissan and NEC. The pack consists of 192 pouch cells in a module of four, two in series and two in parallel.

The modules are stacked, each module is individually sealed, and heat is transferred from the core to the metal outer layer of the module to the outer layer of the battery pack using a passive thermal management system. Leaf’s battery management system is centrally managed, with a single control unit connected to each module by a wire harness. The lithium ion car battery pack is mounted on the bottom of the car, with an integral seal designed to prevent dust and liquids from entering.

Renault, nissan’s Leaf sister company, has released a number of pure electric vehicles, including the Renault Twizy, a small urban two-person car powered by a 6.1kwh lithium ion car battery; Renault Zoe, a mid-sized four-door sedan, is powered by a 22kWh lithium ion car battery;

The Renault Kangoo Van, powered by a 22kwh lithium ion battery, is one of the more interesting features of Renault electric cars, which enjoy Renault’s battery swap service, which allows consumers to replace depleted batteries with new ones at Renault Quickdrop service stations. Initially all Nissan and Renault electric cars used AESC batteries, but recently the search for a new battery supplier has begun to reduce the price.

Ford released a pure electric vehicle called Focus, which was originally converted from an internal combustion engine system to a Magna E-Car pure electric system. Its 23 kWh liquid-cooled lithium ion car battery power system was integrated by replacing the internal combustion engine with an electric drive by a 23-kwH liquid-cooled battery designed by LG Chem.

This unusual battery system design, comes in two separate boxes. One box is mounted under the back seat and the second is mounted in the trunk. The liquid-cooled thermal management system ensures that the temperatures of the two battery strings are almost the same. In addition, by using a liquid-cooled system solution, the battery is kept at the right temperature in both winter and summer.
Gm has also released an all-electric small car, the Chevrolet Spark, which was originally powered by A123’s 21.3kWh lithium iron phosphate battery pack, but in its 2014 model, battery assembly was completely reassembled by LG Chem’s U.S.

Battery assembly is also done “quasi-in-house” at an assembly plant built by GENERAL Motors next to the Volt battery in the Brownstone area. The new lithium ion car battery packs have a slightly lower capacity, around 19kWh, but both meet the requirement to have the same range as the original battery. This change allows GE to generalize both cell and module design to help reduce battery cost. Although the battery’s electricity and control system may be the same, the assembly process of the battery pack is completely redesigned in order to assemble the battery within Spark. The lithium ion car battery pack is installed under the vehicle, such as under the rear seat and the trunk.

Fuel cell electric vehicles

Another potential game changer in the energy production and transportation industry is fuel cells. Fuel cells use a polymer electrolyte membrane (proton exchange membrane) and use hydrogen as a fuel source plus oxygen from the air to produce electricity. They are actually generators, but they generally require a relatively small load energy reserve to ensure a constant supply of electricity, which makes FCV electric. Integrating energy storage systems through the use of fuel cells makes it feasible to reduce the size of hydrogen storage tanks by adding larger batteries. The lithium ion car battery also allows the vehicle to compensate for the energy in regenerative braking.

Most automakers are already working on fuel-cell vehicles. Honda unveiled the Honda FCX Clarity fuel cell car, which incorporates a 288V lithium ion car battery. Similarly, Hyundai Has unveiled a Tuscon fuel cell vehicle that incorporates a 188V lithium ion car battery. General motors introduced the latest fuel cell technology and planned to achieve mass production, while Toyota, BMW, mercedes-benz, Mazda, fiat, audi, nissan and Volkswagen all began to develop fuel cell vehicles.

Fuel cells are also used in the field of large-scale energy storage and even play an important role in the development of some countries or regions. In Japan, small fuel cells are often used as household backup power sources.
Although many manufacturers are developing fuel cells, it may be some time before they are ready for full-scale use. Fuel cell technology is developing rapidly. The main problem of industrial application is how to construct oxygen supply infrastructure. Only when hydrogen energy supply is well developed, fuel cell can get people’s attention in practical application.

All of the above are relatively large power batteries for cars. In a wide range of application scenarios, lithium ion batteries are often used as golf cart batteries to power light vehicles.