Unit 4 _ehv.pptxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

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1. Unit : 4 Types of Storage Systems: Electrical and Hybrid Vehicle (EHV)

2. Unit : 4 Types of Storage Systems:

3. Energy Storage “Energy storages” are defined as the devices that store energy , deliver energy outside (discharge), and accept energy from outside (charge). There are several types of energy storages that have been proposed for electric vehicle (EV) and hybrid electric vehicle (HEV) applications. These energy storages , so far, mainly include chemical batteries, ultra-capacitors or super-capacitors , fuel cell and ultrahigh-speed flywheels.

4. Energy Storage There are a number of requirements for energy storage applied in an automotive application, such as specific energy, specific power, efficiency, maintenance requirement, management, cost, environmental adaptation and friendliness , and safety . For allocation on an EV, specific energy is the first consideration since it limits the vehicle range. On the other hand, for HEV applications , specific energy becomes less important and specific power is the first consideration , because all the energy is from the energy source (engine or fuel cell ) and sufficient power is needed to ensure vehicle performance, particularly during acceleration, hill climbing, and regenerative braking .

5. Battery In nearly all road vehicles the battery is a key component. In the classical EV the battery is the only energy store, and the component with the highest cost , weight and volume. In hybrid vehicles the battery, which must continually accept and give out electrical energy, is also a key component of the highest importance. Some fuel cell (FC) vehicles have been made which have batteries that are no larger than those normally fitted to IC engine cars, but it is probably that most early FC-powered vehicles will have quite large batteries and work in hybrid FC/battery mode .

6. Batteries A battery consists of two or more electric cells joined together. The cells convert chemical energy to electrical energy. The cells consist of positive and negative electrodes joined by an electrolyte. It is the chemical reaction between the electrodes and the electrolyte which generates DC electricity. In the case of secondary or rechargeable batteries , the chemical reaction can be reversed by reversing the current and the battery returned to a charged state.

7. Batteries The ‘lead acid’ battery is the most well known rechargeable type. At present Lead acid , nickel iron, nickel cadmium , nickel metal hydride, lithium polymer and lithium iron , sodium sulphur and sodium metal chloride.

8. Electric vehicles (EVs) primarily use lithium-ion batteries . These batteries are favored for EVs because they offer a high energy density, long cycle life, and relatively low self-discharge compared to other battery types. Lithium-ion batteries also provide the necessary power output and efficiency needed for the extended range and performance of modern EVs. There are several variations of lithium-ion batteries, each with different chemistries to balance aspects like energy density, cost, safety, and lifespan: Nickel Cobalt Manganese (NCM or NMC) : Commonly used in many EVs, offering a balance of energy density, power, and longevity. Nickel Cobalt Aluminum (NCA) : Known for high energy density and used in some Tesla models. Lithium Iron Phosphate (LFP) : Offers better thermal stability and safety, with a longer lifespan but slightly lower energy density. It's becoming more popular in EVs, especially for models that prioritize safety and longevity. Advancements in battery technology are ongoing, with research into solid-state batteries, which promise even higher energy densities, faster charging, and improved safety.

9. Overview of Batteries From the electric vehicle designer’s point of view the battery can be treated as a ‘black box ’ which has a range of performance criteria. These criteria will include: Specific energy Energy density Specific power Typical voltages Amp hour efficiency Energy efficiency Commercial availability Cost, operating temperatures Self-discharge rates Number of life cycles Recharge rates

10. Overview of Batteries The designer also needs to understand how energy availability varies with regard to : Ambient temperature Charge and discharge rates Battery geometry Optimum temperature Charging methods Cooling needs

11. Battery Parameters Cell and battery voltages All electric cells have nominal voltages which gives the approximate voltage when the cell is delivering electrical power . The cells can be connected in series to give the overall voltage required . The battery is represented as having a fixed voltage E, but the voltage at the terminals is a different voltage V , because of the voltage across the internal resistance R. Assuming that a current I is flowing out of the battery.

12. Battery Parameters Charge (or Ahr ) capacity The electric charge that a battery can supply is clearly a most crucial parameter. The SI unit for this is the Coulomb, the charge when one Amp flows for one second. The capacity of a battery might be, say, 10Amphours. This means it can provide 1Amp for 10 hours .

13. Battery Parameters Energy stored The energy stored in a battery depends on its voltage, and the charge stored . The SI unit is the Joule, but this is an inconveniently small unit, and so we use the Whr instead . Specific energy Specific energy is the amount of electrical energy stored for every kilogram of battery mass . It has units of Wh.k 1 Power Density Power density measures how quickly a battery can deliver energy. It's important for acceleration, regenerative braking, and fast charging. Batteries with high power density can provide rapid bursts of energy, improving vehicle performance Energy density Energy density is a critical parameter for EV batteries. It refers to the amount of energy a battery can store per unit of weight or volume. High energy density batteries enable longer driving ranges for EVs without significantly increasing their weight or size. It normally has units of Wh.m −3 .

14. Battery Parameters Specific power Specific power is the amount of power obtained per kilogram of battery. It is a highly variable and rather anomalous quantity, since the power given out by the battery depends far more upon the load connected to it than the battery itself. Ahr (or charge) efficiency In an ideal world a battery would return the entire charge put into it, in which case the amp hour efficiency is 100%. However, no battery does; its charging efficiency is less than 100%. The precise value will vary with different types of battery, temperature and rate of charge. It will also vary with the state of charge. Energy efficiency This is another very important parameter and it is defined as the ratio of electrical energy supplied by a battery to the amount of electrical energy required to return it to the state before discharge.

15. Battery Parameters Self-discharge rates Most batteries discharge when left unused, and this is known as self-discharge . This is important as it means some batteries cannot be left for long periods without recharging. The rate varies with battery type, and with other factors such as temperature; higher temperatures greatly increase self-discharge. Battery temperature, heating and cooling needs Although most batteries run at ambient temperature, some run at higher temperatures and need heating to start with and then cooling when in use. In others, battery performance drops off at low temperatures, which is undesirable, but this problem could be overcome by heating the battery. When choosing a battery the designer needs to be aware of battery temperature , heating and cooling needs, and has to take these into consideration during the vehicle design process.

16. Battery Parameters Battery life and number of deep cycles Most rechargeable batteries will only undergo a few hundred deep cycles to 20% of the battery charge. However , the exact number depends on the battery type, and also on the details of the battery design, and on how the battery is used. This is a very important figure in a battery specification , as it reflects in the lifetime of the battery, which in turn reflects in electric vehicle running costs.

17. Range vs. Cost Trade-off: Battery capacity directly affects an EV's driving range. However, larger batteries are costlier. Analyzing the balance between range and cost is essential for optimizing the EV's value proposition. Battery Chemistry: Different battery chemistries, such as lithium-ion, lithium-polymer, and solid-state batteries, offer varying performance characteristics. Analyzing the pros and cons of each chemistry is crucial for selecting the right battery for EVs. Cycle Life: Battery cycle life refers to the number of charge-discharge cycles a battery can undergo before its capacity significantly degrades. Long cycle life is essential to ensure the longevity of an EV's battery pack. Charging Infrastructure: The availability and capacity of charging infrastructure impact the practicality of EVs. Fast-charging technology and widespread charging networks are essential for the convenience of EV owners .

18. Cost-Benefit Analysis: - Evaluating the total cost of ownership (TCO) of an EV, including the battery, maintenance, and electricity costs, is essential for consumers and fleet operators. Second-Life Use: - Investigating potential second-life applications for EV batteries, such as energy storage for homes or grid stabilization, can extend their usefulness. Recycling and Disposal: - Analyzing end-of-life strategies for batteries, including recycling and proper disposal, is crucial for minimizing environmental impact. Regulatory Compliance: - Compliance with safety and environmental regulations is essential for battery manufacturing and EV operation.

19. Thermal Management: EV batteries generate heat during charging and discharging, affecting performance and longevity. Effective thermal management systems are essential to maintain battery health. Environmental Impact: Assessing the environmental impact of battery production, usage, and disposal is vital. Analyzing the life cycle emissions and sustainability of battery materials helps make informed decisions. Energy Storage Management: Advanced battery management systems (BMS) optimize charging and discharging to maximize battery life and performance. Analyzing BMS data can provide insights into battery health and usage patterns.

20. The choice of battery type for an electric vehicle depends on factors like cost, performance requirements, safety, and availability of materials. As technology continues to advance, the EV industry is likely to see ongoing improvements in battery technology, including higher energy density, faster charging, and increased sustainability.

21. The range of electric two-wheelers, such as scooters and motorcycles, varies depending on factors like battery capacity, motor efficiency, and riding conditions. Here's a general overview: 1. Entry-Level Electric Two-Wheelers Range : 30 to 60 km (18 to 37 miles) per charge. Battery Capacity : Typically 1 kWh to 2 kWh . Use Case : Ideal for short commutes and city riding. Examples : Hero Electric Optima, Ampere Reo. 2. Mid-Range Electric Two-Wheelers Range : 60 to 100 km (37 to 62 miles) per charge. Battery Capacity : Around 2 kWh to 3.5 kWh . Use Case : Suitable for moderate commutes and urban areas. Examples : Ather 450X, Bajaj Chetak , TVS iQube .

22. 3. High-End Electric Two-Wheelers Range : 100 to 150 km (62 to 93 miles) or more per charge. Battery Capacity : Typically 4 kWh to 6 kWh or higher. Use Case : Longer commutes, touring, or high-performance needs. Examples : Revolt RV400, Ola S1 Pro. 4. Performance Electric Motorcycles Range : 150 to 250 km (93 to 155 miles) per charge. Battery Capacity : Higher capacity, usually 6 kWh to 10 kWh or more. Use Case : High-speed performance, longer rides, and touring. Examples : Zero SR/F, Harley-Davidson LiveWire . Factors Affecting Range: Speed : Higher speeds consume more energy, reducing range. Riding Mode : Eco modes extend range, while Sport modes reduce it. Terrain : Hilly or rough terrain requires more power, decreasing range. Weight : Additional rider or cargo weight can reduce range. Weather Conditions : Extreme temperatures can affect battery efficiency.

23. Types of Battery Electric vehicles (EVs) use a variety of battery types, but the most common and widely used battery chemistry for EVs is lithium-ion (Li-ion). Li-ion batteries offer a good balance of energy density, power density, and overall performance for electric vehicles. However, there are other battery types and emerging technologies being explored for EV applications.

24.   Lithium-Ion (Li-ion) Batteries: Li-ion batteries are the most prevalent battery technology in electric vehicles today. They offer high energy density, providing a good balance between range and weight. Li-ion batteries have a relatively long cycle life and can be fast-charged, making them suitable for various EV applications . Lithium-Polymer ( LiPo ) Batteries: LiPo batteries are similar to Li-ion batteries but use a solid or gel-like electrolyte. They offer flexibility in terms of packaging and can be shaped to fit specific vehicle designs. LiPo batteries are less common in passenger EVs but are used in some niche applications.

25. Lithium-Iron-Phosphate (LiFePO4) Batteries: LiFePO4 batteries are known for their safety, stability, and long cycle life. They have a lower energy density compared to traditional Li-ion batteries but are less prone to thermal runaway. LiFePO4 batteries are used in some electric buses and commercial vehicles. Solid-State Batteries: Solid-state batteries are an emerging technology that replaces the liquid electrolyte in Li-ion batteries with a solid electrolyte. They offer the potential for higher energy density, faster charging, and improved safety. Solid-state batteries are still in the development and early adoption stages but hold promise for future EVs.

26. Nickel-Metal Hydride (NiMH) Batteries: NiMH batteries were once commonly used in hybrid electric vehicles (HEVs) like the Toyota Prius. They offer good durability and reliability but have lower energy density compared to Li-ion batteries. NiMH batteries have been largely replaced by Li-ion technology in modern EVs. Nickel-Cadmium ( NiCd ) Batteries: NiCd batteries were used in some early electric vehicles but are now rarely used due to environmental concerns associated with cadmium. They have been largely replaced by NiMH and Li-ion technologies.

27. Sodium-Ion Batteries: Sodium-ion batteries are being explored as a potential alternative to Li-ion batteries. They use sodium as the charge carrier instead of lithium and have the advantage of using more abundant materials. Sodium-ion batteries are still in the research and development stage for EV applications. Hydrogen Fuel Cells: While not technically batteries, hydrogen fuel cells are an alternative to battery-electric vehicles. They use hydrogen gas to generate electricity through a chemical reaction with oxygen, emitting only water as a byproduct . Fuel cell vehicles (FCVs) are considered electric vehicles but rely on fuel cells instead of batteries for electricity generation. The choice of battery type for an electric vehicle depends on factors like cost, performance requirements, safety, and availability of materials. As technology continues to advance, the EV industry is likely to see ongoing improvements in battery technology, including higher energy density, faster charging, and increased sustainability .

28. Lead Acid Batteries Chemical Reactions : During Discharge (when the battery is providing power): At the positive plate (PbO2), lead dioxide (PbO2) reacts with sulfuric acid (H2SO4) to form lead sulfate (PbSO4) and water (H2O) while releasing electrons. PbO2 + H2SO4 → PbSO4 + H2O + 2e- At the negative plate ( Pb ), sponge lead ( Pb ) reacts with sulfuric acid to form lead sulfate and release electrons. Pb + H2SO4 → PbSO4 + 2e- Electrons flow from the negative plate through an external circuit to the positive plate, creating an electric current that can power devices connected to the battery.

29. Lead Acid Batteries A lead-acid battery is a type of rechargeable battery commonly used in various applications, including automotive vehicles, uninterruptible power supplies (UPS), and backup power systems. It operates based on chemical reactions that occur between lead dioxide (PbO2) and sponge lead ( Pb ) electrodes immersed in a sulfuric acid (H2SO4) electrolyte solution. Here's a simplified explanation of how a lead-acid battery works: Basic Components : A lead-acid battery consists of several key components: Positive Plate (PbO2) : This is typically made of lead dioxide. Negative Plate ( Pb ) : This is usually made of sponge lead. Separator : It's a porous material that keeps the positive and negative plates from coming into direct contact. Electrolyte : A diluted sulfuric acid solution that serves as the medium for ion exchange between the plates.

30. Lead Acid Batteries Charge and Reversal : When the battery is being charged, an external voltage source is applied across the battery terminals. This reverses the chemical reactions: lead sulfate at the positive and negative plates converts back into lead dioxide and sponge lead, respectively, while consuming electrical energy from the charger. The sulfuric acid concentration in the electrolyte increases during charging. Electrolyte Concentration : Over time, as the battery is discharged and recharged, the sulfuric acid in the electrolyte is consumed and the concentration decreases. A decrease in sulfuric acid concentration can reduce the battery's capacity and performance.

31. Lead Acid Batteries Maintenance : To ensure the longevity and performance of lead-acid batteries, they may require periodic maintenance, including topping off with distilled water to maintain the proper electrolyte level and specific gravity. Safety Considerations : Lead-acid batteries can produce hydrogen gas during charging, which can be flammable and pose safety risks. Adequate ventilation is necessary when using or charging these batteries. Lead-acid batteries are known for their reliability and ability to deliver high current, which makes them suitable for applications requiring a burst of power, such as starting a car engine. However, they have certain limitations, including relatively low energy density and sensitivity to deep discharges, which can reduce their lifespan.

32. Lithium-ion batteries Lithium-ion batteries, often abbreviated as Li-ion batteries, are widely used in various applications, from portable electronics like smartphones and laptops to electric vehicles and renewable energy storage systems. These batteries work based on the movement of lithium ions between the battery's positive and negative electrodes during charging and discharging cycles. Here's how a typical lithium-ion battery works:

33. Lithium-ion batteries 1. Anode (Negative Electrode): The anode of a lithium-ion battery is typically made of a carbon-based material, such as graphite. When the battery is in a discharged state, the anode is host to lithium ions. During charging, lithium ions are stored in the anode as the battery takes in electrical energy. 2. Cathode (Positive Electrode): The cathode is typically composed of a lithium-containing compound, which can vary depending on the specific type of lithium-ion battery. Common cathode materials include lithium cobalt oxide (LiCoO2), lithium iron phosphate (LiFePO4), and others. When the battery is charged, the cathode undergoes a chemical reaction that involves the movement of lithium ions from the anode to the cathode.

34. Lithium-ion batteries involves the movement of lithium ions from the anode to the cathode. 3. Electrolyte: A lithium-ion battery uses a lithium-ion-conductive electrolyte, which is typically a lithium salt dissolved in a solvent. This electrolyte allows lithium ions to move from the anode to the cathode and vice versa while maintaining electrical neutrality within the battery. 4. Separator: A separator material is placed between the anode and cathode to prevent them from coming into direct contact with each other. If the anode and cathode were to touch, it could result in a short circuit and potentially lead to a safety hazard. The separator is porous and allows the passage of lithium ions while blocking the flow of electrons.

35. Lithium-ion batteries Charging: When you connect the battery to a charger, an external voltage is applied across the battery terminals. Lithium ions from the anode move through the electrolyte and separator to the cathode due to the voltage difference. These ions are stored in the cathode material. The process continues until the cathode is fully saturated with lithium ions, indicating that the battery is fully charged. Discharging: When you use the battery to power a device, an external circuit is connected to the battery terminals. Lithium ions stored in the cathode start moving back to the anode through the electrolyte and separator. This flow of lithium ions generates an electric current, which can be used to power your device. As the lithium ions return to the anode, the battery discharges, and its stored energy is used to provide electrical power.

36. Lithium-ion batteries The chemical reactions that take place during charging and discharging are reversible, allowing lithium-ion batteries to be recharged and discharged multiple times before their capacity starts to degrade significantly. The specific materials used in the anode, cathode, and electrolyte can vary, leading to different types of lithium-ion batteries with varying performance characteristics.

37. Lithium-ion batteries Lithium-ion batteries (Li-ion batteries) are known for several key characteristics that have made them a popular choice for various applications. Here are some of the key characteristics of lithium-ion batteries: High Energy Density: Li-ion batteries have a high energy density, meaning they can store a significant amount of energy in a relatively small and lightweight package. This characteristic makes them ideal for portable electronics, electric vehicles (EVs), and other applications where size and weight are crucial factors. Rechargeable: Li-ion batteries are rechargeable, allowing them to be used multiple times. They can go through hundreds to thousands of charge-discharge cycles before their capacity starts to significantly degrade. This makes them cost-effective in the long run.

38. Lithium-ion batteries Low Self-Discharge Rate: Li-ion batteries have a relatively low self-discharge rate, which means they can hold their charge for an extended period when not in use. This makes them suitable for devices that are not used regularly, such as emergency backup systems. Wide Range of Applications: Li-ion batteries are versatile and used in a wide range of applications, including smartphones, laptops, digital cameras, power tools, electric vehicles, renewable energy storage systems, and more. Fast Charging: Li-ion batteries can support fast-charging technologies, allowing users to charge their devices quickly. However, the charging speed may vary depending on the specific battery chemistry and design. Reliable Voltage: Li-ion batteries provide a relatively stable voltage throughout most of their discharge cycle. This feature ensures that electronic devices receive a consistent power supply, maintaining performance until the battery is depleted.

39. Lithium-ion batteries Lightweight: Li-ion batteries are lightweight compared to many other battery chemistries, which is important for portable devices and electric vehicles where weight is a critical factor. Low Maintenance: Li-ion batteries require minimal maintenance compared to some other battery types. They do not need periodic discharge and recharge cycles (as required by some older battery technologies), and they have no memory effect. High Cycle Life: Depending on the specific chemistry and usage, Li-ion batteries can have a relatively high cycle life, which is the number of charge-discharge cycles a battery can endure before capacity significantly diminishes. Environmental Considerations: Li-ion batteries are generally considered more environmentally friendly than some other battery chemistries, like nickel-cadmium ( NiCd ), due to the absence of toxic heavy metals in their composition. However, recycling and disposal of Li-ion batteries should still be done properly to minimize environmental impact.

40. Lithium-ion batteries It's important to note that there are different types of Li-ion batteries, each with slightly different characteristics and trade-offs. The choice of Li-ion chemistry depends on the specific requirements of the application. For example, lithium iron phosphate (LiFePO4) batteries are known for their safety and long cycle life, while lithium cobalt oxide (LiCoO2) batteries offer high energy density but may have somewhat shorter cycle lives.

41. Battery voltage The voltage of battery cells in an electric vehicle (EV) battery pack can vary depending on the specific chemistry and design of the battery . Lithium-Ion Batteries: These are the most common type of batteries used in EVs. A single lithium-ion cell typically has a nominal voltage of around 3.6 to 3.7 volts. When fully charged, it can have a voltage of around 4.2 to 4.35 volts. In an EV battery pack, multiple cells are connected in series to achieve the desired voltage level. Common voltages for EV battery packs can range from 200 to 800 volts or more, depending on the manufacturer and model.

42. Lithium Iron Phosphate (LiFePO4) Batteries: LiFePO4 batteries are another type of lithium-ion battery, known for their stability and safety. They typically have a nominal voltage of around 3.2 to 3.3 volts per cell. In an EV battery pack, multiple cells are connected in series to achieve the desired pack voltage. Other Chemistries: There are other battery chemistries used in EVs, such as solid-state batteries and advanced lithium-ion variants. Each may have its own voltage characteristics . It's important to note that the total voltage of an EV battery pack is determined by the number of cells connected in series. For example, if you have 100 lithium-ion cells each with a nominal voltage of 3.6 volts connected in series, the total pack voltage would be 360 volts (100 cells * 3.6 volts). This pack voltage is what powers the electric motor and other vehicle systems. Additionally, battery management systems (BMS) are used in EVs to monitor and manage the individual cell voltages within the pack to ensure safe operation and to prevent overcharging or over-discharging of the cells

43. Lead Acid Batteries

44. Battery Parameters Table I Showing the state of charge of two different cells in a battery

45. Battery Modeling

46. Battery Equivalent Circuit Although the equivalent circuit is simple, we do need to understand that the values of the circuit parameters (E and R) are not constant. The open-circuit voltage of the battery E is the most important to establish first . This changes with the state of charge of the battery.

47. Battery Equivalent Circuit

48. Battery Equivalent Circuit

49. Modeling Battery Capacity

50. Modeling Battery Capacity

51. Modeling Battery Capacity

52. Modeling Battery Capacity

53. Simulating Battery at a set Power

54. the current I is flowing into the battery (charging), then the equation becomes:

55. Simulating Battery at a set Power

56. Simulating Battery at a set Power

57. Conclusion

58. Conclusion

59. Super Capacitor Capacitors are devices in which two conducting plates are separated by an insulator. A DC voltage is connected across the capacitor, one plate being positive the other negative. The opposite charges on the plates attract and hence store energy. The charge Q stored in a capacitor of capacitance C Farads at a voltage of V Volts is given by the equation

60. Supercapacitors Supercapacitors and traditional capacitors, while sharing similarities in their basic function of storing electrical charge, have several key differences in terms of their construction, energy storage mechanisms, and applications: Energy Storage Mechanism : Capacitors : Traditional capacitors store electrical energy by accumulating electric charge on two conductive plates, separated by an insulating material (dielectric). They store energy in an electric field between the plates. Capacitors are typically designed for low energy storage and provide rapid discharge but have limited energy capacity. Supercapacitors : Supercapacitors , on the other hand, store energy primarily through two mechanisms: double-layer capacitance and, in some cases, pseudocapacitance . Double-layer capacitance occurs at the interface between the electrode and electrolyte, storing energy electrostatically. Pseudocapacitance involves reversible redox reactions at the electrode-electrolyte interface. Supercapacitors can store significantly more energy compared to traditional capacitors and offer high power density.

61. Energy Density : Capacitors : Traditional capacitors have relatively low energy density, which means they can store a small amount of energy per unit volume or mass. They are suitable for applications requiring rapid energy discharge. Supercapacitors : Supercapacitors have higher energy density compared to traditional capacitors. While they still have lower energy density compared to batteries, they can store more energy than capacitors and deliver it quickly. This makes them valuable for applications that require both high power and moderate energy storage. Voltage Ratings : Capacitors : Traditional capacitors can handle relatively high voltage ratings, often in the range of tens to hundreds of volts. Supercapacitors : Supercapacitors typically have lower voltage ratings compared to traditional capacitors. They are commonly used in low-voltage applications, often below 3 volts per cell. To achieve higher voltage ratings, multiple supercapacitor cells must be connected in series

62. Charge/Discharge Rate : Capacitors : Traditional capacitors can charge and discharge very quickly, often in a matter of microseconds. Supercapacitors : Supercapacitors excel at rapid charge and discharge, with even faster response times than traditional capacitors. They are ideal for applications that require high-power bursts. Cycle Life : Capacitors : Traditional capacitors have virtually unlimited cycle life because their energy storage mechanism does not involve chemical reactions. Supercapacitors : Supercapacitors also have a high cycle life, but it is typically limited compared to traditional capacitors due to potential electrode degradation over time. Nevertheless, they can still withstand hundreds of thousands of charge/discharge cycles.

63. Applications : Capacitors : Traditional capacitors are commonly used for tasks like filtering and energy storage in electronic circuits, but they are not suitable for applications requiring high energy storage or rapid energy release. Supercapacitors : Supercapacitors find applications in various fields, including regenerative braking systems in electric vehicles, backup power systems, renewable energy storage, and as auxiliary power sources in electronics. They are favored when a combination of high power, fast response, and moderate energy storage is required. In summary, while both traditional capacitors and supercapacitors store electrical charge, they differ in energy storage mechanisms, energy density, voltage ratings, charge/discharge rates, and applications. Supercapacitors are designed to bridge the gap between traditional capacitors and batteries, offering a unique combination of high power and moderate energy storage capacity.

64. https://www.youtube.com/watch?v=WUZqgAtKMJg

65. Super Capacitor

66. Super Capacitor Double-layer capacitor technology is the major approach to achieving the ultracapacitor concept. The basic principle of a double-layer capacitor is illustrated . When two carbon rods are immersed in a thin sulfuric acid solution, separated from each other and charged with voltage increasing from zero to 1.5 V, almost nothing happens up to 1 V; then at a little over 1.2 V, a small bubble will appear on the surface of both the electrodes. Those bubbles at a voltage above 1 V indicate electrical decomposition of water. Below the decomposition voltage, while the current does not flow, an “electric double layer” then occurs at the boundary of electrode and electrolyte. The electrons are charged across the double layer and for a capacitor. An electrical double layer works as an insulator only below the decomposing voltage. The stored energy, Ecap , is expressed as where C is the capacitance in Faraday and V is the usable voltage in volt. This equation indicates that the higher rated voltage V is desirable for larger energy density capacitors.

67. Super Capacitor

68. Super Capacitor There is great merit in using an electric double layer in place of plastic or aluminium oxide films in a capacitor, since the double layer is very thin — as thin as one molecule with no pin holes — and the capacity per area is quite large, at 2.5 to 5 μF /cm2.Even if a few μF /cm2 are obtainable, the energy density of capacitors is not large when using aluminium foil. For increasing capacitance, electrodes are made from specific materials that have a very large area, such as activated carbons, which are famous for their surface areas of 1,000 to 3,000 m2/g. To those surfaces, ions are adsorbed and result in 50 F/g (1,000 m2/g_5F/cm2_10,000 cm2/m2_50 F/g). Assuming that the same weight of electrolyte is added, 25 F/g is quite a large capacity density. Nevertheless, the energy density of these capacitors is far smaller than secondary batteries. the typical specific energy of ultracapacitors at present is about 2 Wh /kg, only1/20 of 40 Wh /kg, which is the available value of typical lead-acid batteries.

69. Ragone plot of Batteries, Supercapacitors and Flywheels

70. Super Capacitor Performance of Ultracapacitors : Ultracapacitor equivalent circuit:

71. Performance of Ultracapacitors

72. Where i is the discharge current, which is a function of time in real operation. At different discharge current rates, the voltage decreases linearly with discharge time. At a large discharge current rate, the voltage decreases much faster than at a small current rate. Block diagram of the ultracapacitor model

73. Super Capacitor Discharge characteristics of the 2600 F Maxwell Technologies ultracapacitor

74. Discharge efficiency of the 2600 F Maxwell Technologies ultracapacitor

75. For example, when the cell voltage drops from rated voltage to 60% of the rated voltage, 64% of the total energy is available for us

76. Flywheels

77. Flywheels

78. Flywheels

79. Flywheels

80. Flywheels

81. Flywheels FLYWHEEL TECHNOLOGIES : Basic structure of a typical flywheel system:

82. Flywheels FLYWHEEL TECHNOLOGIES : Basic structure of a typical flywheel system:

83. Flywheels

84. Flywheels

85. Flywheels

86. Flywheels

87. Flywheels

88. Flywheels

89. Fuel Cell In recent decades, the application of fuel cells in vehicles has been the focus of increased attention. In contrast to a chemical battery, the fuel cell generates electric energy rather than storing it and continues to do so as long as a fuel supply is maintained. Compared with the battery-powered electric vehicles (EVs), the fuel cell-powered vehicle has the advantages of a longer driving range without a long battery charging time. Compared with the internal combustion engine (ICE) vehicles, it has the advantages of high energy efficiency and much lower emissions due to the direct conversion of free energy in the fuel into electric energy, without undergoing combustion.

90. Operating Principles of Fuel Cells A fuel cell is a galvanic cell in which the chemical energy of a fuel is converted directly into electrical energy by means of electrochemical processes. The fuel and oxidizing agents are continuously and separately supplied to the two electrodes of the cell, where they undergo a reaction. An electrolyte is necessary to conduct the ions from one electrode to the other. The fuel is supplied to the anode or positive electrode, where electrons are released from the fuel under catalyst. The electrons, under the potential difference between these two electrodes, flow through the external circuit to the cathode electrode or negative electrode, where, in combination with positive ions and oxygen, reaction products, or exhaust, are produced

91. https:// www.youtube.com/watch?v=rzdBHr3v5mc https:// www.youtube.com/watch?v=NTwHD2n-vRI https:// www.youtube.com/watch?v=tajigZ2e6tQ

92. Fuel Cell Car

93. Main issues in the fuel cell

94. Hydrogen Fuel Cells: Basic Principles Electrode reactions:

95. Different electrolytes

96. Data for different types of fuel cell

97. Fuel cell

98. Fuel cell characteristic

99. Hydrogen fuel cell system

100. Hybridization of different Energy Storage devices The hybridization of energy storage is to combine two or more energy storages together so that the advantages of each one can be brought out and the disadvantages can be compensated by others. For instance, the hybridization of a chemical battery with an ultracapacitor can overcome such problems as low specific power of electrochemical batteries and low specific energy of ultracapacitors , therefore achieving high specific energy and high specific power.

101. Basically, the hybridized energy storage consists of two basic energy storages: one with high specific energy and the other with high specific power. In high power demand operations, such as acceleration and hill climbing, both basic energy storages deliver their power to the load as shown in Figure below.

102. In low power demand operation, such as constant speed cruising operations, the high specific energy storage will deliver its power to the load and charge the high specific power storage to recover its charge lost during high power demand operation, as shown in Figure below

103. In regenerative braking operations, the peak power will be absorbed by the high specific power storage, and only a limited part is absorbed by the high specific energy storage.

104. Battery and Ultracapacitor Hybrids Ultracapacitor can offer much higher power than batteries, and it collaborates with various batteries to form the battery and ultracapacitor hybrids. The major disadvantages of this configuration are that the power flow cannot be actively controlled and the ultracapacitor energy cannot be fully used.

105. A configuration in which a two-quadrant DC/DC converter is placed between the batteries and ultracapacitors . This design allows the batteries and the ultracapacitors to have a different voltage, the power flow between them can be actively controlled, and the energy in the ultracapacitors can be fully used. In the long term, an ultrahigh-speed flywheel would replace the batteries in hybrid energy storage to obtain a high efficiency, compact, and long-life storage system for EVs and HEVs.

106. A simple hybrid fuel cell system

107. A hybrid fuel cell system with both batteries and ultracapacitors

108. Sizing the drive system Matching the electric machine and the internal combustion engine (ICE), Sizing the propulsion motor, sizing the power electronics, selecting the energy storage technology, Calculation for the ratings

109. Electric Propulsion System

110. Electric Propulsion System

111. Sizing the drive system The vehicle power plant must be sized for the target vehicle mass, load requirements and performance goals. Vehicle propulsion system traction is set by the vehicle design mass and acceleration performance according to Newton’s law, F = ma

112. Matching the electric drive and ICE One of the most common matching elements used in hybrid electric passenger vehicles is the epicyclic , or planetary, gear set. An  epicyclic gear train (also known as a planetary gearset ) consists of two gears mounted so that the center of one gear revolves around the center of the other. A carrier connects the centers of the two gears and rotates to carry one gear, called the planet gear or planet pinion, around the other, called the sun gear or sun wheel.  https://www.youtube.com/watch?v=gDnATml2lHQ

113. Epicyclic Gear train Schematic of epicyclic gear set

114. Epicyclic gear input–output relationship

115. Sizing the propulsion motor An electric machine is at the core of hybrid propulsion regardless of whether or not the vehicle is gasoline–electric, diesel–electric or fuel cell electric. Propulsion is via an ac drive system consisting of an energy storage unit, a power processor, the M/G and vehicle driveline and wheels. Hybrid vehicle drive train

116. Most electric machines rated for vehicle traction applications are limited to 12 000 rpm for several inherent reasons: rotor burst limits, rotor position sensing encoders and their attendant digital interface, bearing system, critical speeds of the M/G geometry.

117. M/G torque-speed capability envelope

118. M/G operating envelope for hybrid propulsion

119. Machine sizing The electric machine is physically sized by its torque specification. Electric machine torque is determined by the amount of flux the iron can carry and the amount of current the conductors can carry plus the physical geometry of the machine. Machine torque = where k = constant that includes geometry variables = The product of electric and magnetic loading (volumetric shear force) = stator bore volume

120. Machine sizing

121. Machine sizing

122. Sizing the power electronics

123. Sizing the power electronics

124. Sizing the power electronics

125. Sizing the power electronics

126. Sizing the power electronics

127. Sizing the power electronics

128. Sizing the power electronics

129. Sizing the power electronics

130. Sizing the power electronics

131. Selecting the energy storage technology

132. City bus parameters used in sizing study for energy storage

133. Selecting the energy storage technology Drive cycle for city bus having two highway and eight city stop–go events

134. Selecting the energy storage technology

135. Selecting the energy storage technology