Will We Ever be Able to Buy a Solar Car?

An electric vehicle is a vehicle that uses electricity as its energy source. Generally, a lead-acid battery or a lithium-ion battery is used for power supply. The solar electric vehicle is based on this, and converts solar energy into electricity to power the vehicle, which greatly reduces the use cost of the electric vehicle and is very environmentally friendly. Its structural performance is more outstanding, and it can timely and effectively supplement the electric power during the field trip of the electric vehicle, enhance the driving power, maintain and extend the battery life. Unique design, convenient installation and use, maintaining the existing configuration and vehicle structure of electric vehicles, is the largest power, lowest price and best performance solar charger of its kind. The service life can reach about 25 years, especially in terms of improving the performance of electric vehicles and reducing the cost of electric vehicles.

Solar energy is a strategic energy source for renewable and sustainable development. As the Wall Street storm sweeps the globe, advanced technologies are everywhere

Solar electric vehicle power system

When a solar electric vehicle with a rated power of a battery panel runs on the road, it usually suffers from air resistance, rolling resistance, gravity, bearing friction and so on. If you need to accelerate or climb, you will also be subject to acceleration resistance or slope resistance. Power is a function of the cube of the vehicle speed. Increasing a small vehicle speed requires a large amount of power, which also requires increasing the area of the solar panel and the weight of the vehicle. Therefore, according to the actual situation, the area and power of the solar panel are combined to average Speed selection.

Solar electric vehicle management system

The driving system of an electric vehicle is like a person's motion system, the electric source is like the "heart" of an electric vehicle, and the management system of the electric vehicle is like the "brain" of the car. The awkwardness of the "brain" and the level of intelligence quotient make it possible for electric vehicles to use a limited electric source to increase driving capacity, increase driving speed, effectively maintain and increase the service life of the electric source, which depends on the management system "brain" How smart.

The driving system of an electric car comes from the power source power system, and the management system controls the working capacity of the power source, so a solar electric car is no exception. Its electric source (solar photovoltaic panel components and batteries), control The system and drive system are under the "leadership" of the energy management system. The energy management system is responsible for the task of all working systems of the entire vehicle in the best state, and collects the operating data of each system for monitoring, diagnosis and management. It also needs to control the charging method, instruct the discharge work, provide remaining power data and current energy display. And other duties.

The most basic function of the energy management system is to provide the best driving mode to improve the driving range; to predict the driving range according to the selected driving mode; to reasonably dispatch the regenerative energy during regenerative (electric) braking; and to protect the battery pack from charging and discharging And alarm (over-voltage, under-voltage, over-temperature) functions; data transmission and effective management of chargers and battery packs and photovoltaic cell modules that generate electricity during charging; and identification and self-diagnosis and self-repair functions.

The energy management system is based on a microprocessor electronic control unit. It connects to various sensor input ports, including temperature sensors inside and outside the car, motors and motor control systems, battery pack control systems, current and voltage sensors, speed and acceleration sensors, and photovoltaic cell display control systems. Its main job is to manage the voltage, current, and temperature of electric sources (including photovoltaic cell displays and battery packs), and to indicate the state of charge and discharge. The control system is the main information part of the energy management system, and the control unit mainly controls the various execution devices based on the information provided by the monitoring system to achieve intelligent energy management.

The energy management system software program must not only be able to monitor and record sensor inputs, but also include electric vehicle functional modules including electric source groups. This module system takes the electric source group, the control system and the load as the main objects. Through optimization calculation, the electric vehicle can achieve the best operating efficiency at any speed and load.

Another task of the intelligent management system is to display important information about electric vehicle driving and fault diagnosis. And without affecting the driving and safety of the vehicle, the economy driving mode is automatically executed to prevent the invalid use of energy. For example, the searchlight is automatically turned off when parking; the air conditioner is automatically adjusted according to the external ambient temperature; the driving mode is compared with the driver's driving mode; the optimal mode is automatically adjusted to achieve energy saving purposes; when the vehicle is downhill or braking, the motor function can be transformed It functions as a generator and is stored in the battery. In addition, it should be able to record the current and historical data of battery charging and discharging, as well as the historical data of the operation of the electric source. The data can be transferred to a computer for software processing to monitor the working status of the electric source. Furthermore, it discovers the hidden dangers of electric source components and faults, and provides accurate diagnosis for electric vehicle maintenance services.

If the management system of an electric vehicle is compared to the "brain" and the electric source system is compared to the "heart", then the control system of the electric vehicle can be compared to "nerves". The control and conduction of the nerves make the electric vehicle move (drive). . The size of the "kinetic energy" of an electric vehicle depends on the electric source. Therefore, the "heart" function is still important. Only full electricity can keep the brain from being deficient in blood supply. Operational capabilities.

Solar electric vehicle battery pack

The battery pack of a solar electric vehicle should reasonably select the capacity of the battery pack according to the power generation capacity of the photovoltaic cell module, so that the battery pack can supply power to the load on rainy days and at night. So what kind of battery to choose, we must do a comprehensive analysis of the performance of various batteries.

The research and development experience of electric vehicle batteries started with lead-acid batteries. Lead-acid power batteries have undergone more than 100 years of development. After people developed nickel-metal hydride power batteries and then lithium-ion power batteries, they were speculated by the industry about the exit history. The stage is up. However, lead-acid batteries are still a mass-produced battery series. Lead-acid battery, as a relatively mature battery technology, has low specific energy, specific power, and energy density, but high cost performance and high rate discharge, and remains the only battery for electric vehicles that can be mass-produced. It is mainly used in mass production. Market of electric bicycles. However, the application of lead-acid batteries in electric vehicles has shortcomings such as short driving range, poor service life, large size, heavy weight, and environmental protection. It is not only hindered in the application of electric vehicles, but wants to become a solar electric vehicle. It is conceivable that the application of the energy storage battery category is difficult.

Before the advent of lithium-ion batteries, nickel-metal hydride batteries were widely used in electric vehicles. Their specific energy reached 75 ~ 80Wh / kg, specific power reached 160 ~ 230w / kg, and the cycle life exceeded 600 times. Because nickel-metal hydride batteries have advantages in terms of safety, they have reached a state of maturity in the application of hybrid electric vehicles. Car manufacturers with better applications, such as Japan's Toyota and American General Motors. However, nickel-metal hydride batteries are far more expensive than lead-acid batteries and have lower energy density than lithium-ion batteries, so it is difficult to become the battery of choice for solar electric vehicles.

Solar electric vehicle

The battery of a solar electric vehicle is charged by a solar photovoltaic panel (it can also be charged by an external power source when there is insufficient light). In order to minimize the weight of the entire electric vehicle and facilitate the operation of the electric vehicle, a large-capacity high-rate energy storage lithium ion battery is selected, which is the best choice for solar electric vehicles. Although the cost of a lithium-ion battery is increased compared with a lead-acid battery, the weight of a lithium-ion battery is more than 4 times lower than that of a lead-acid battery, because the lithium-ion battery has a specific energy, cycle life and self-discharge rate And many aspects of environmental protection have superior performance. Its specific energy can reach 150Wh / kg, which is more than twice that of nickel-metal hydride batteries and more than four times that of lead-acid batteries. Since the specific energy is a quarter of that of a lead-acid battery, analyzing the energy consumption of a lithium-ion battery from this perspective, there are fewer resources. Because lithium-ion batteries use more elements and have richer resources, lead-acid batteries and nickel-metal hydride batteries may further increase prices, and the cost of lithium batteries will be further reduced. The use of lithium-ion batteries in the electric source system of solar electric vehicles is important to reduce weight and improve the lightweight performance of the entire system. In addition, its energy per unit volume is very high, up to 400Wh / L, the volume of the same capacity is one-third to one-fourth of the lead-acid battery, which provides a broader design space for light and flexible design requirements. In addition, the lithium-ion battery has a long repeated charging life, and the cycle number of the single battery can reach more than 1500 times. As a battery pack, if there is a good monitoring and management system, it can reach a balance level of more than 1,000 times during charging and discharging. Because the solar battery can often be float-charged or shallow-charged when in use, its battery pack life will not be as short as that of pure electric vehicles. Another advantage of lithium-ion batteries is the low self-discharge rate, which has considerable benefits in storing electrical energy in continuous cloudy days and at night, which can improve the performance of electric vehicles. Calculated when the charged capacity of the lithium-ion battery is maintained at 60% to 80%, the service life should not be less than 3 to 5 years, and the life is equivalent to about three times that of the lead-acid battery. Because lithium-ion batteries do not contain heavy metals such as lead and cadmium, they are called green batteries in the industry. With the continuous improvement of lithium-ion power battery technology in China, especially in the breakthrough of lithium-ion power battery use, management, and control technology, which will continue to improve the level, the service life of its batteries will also be longer and longer, and the cost performance will also increase. The more advantages, the more widely used in electric vehicles. Lithium-ion batteries are widely used not only in solar electric vehicles, pure electric vehicles, and fuel cell vehicles, but also in aerospace, marine and other fields. Hyundai s internationally advanced lithium-iron and lithium-manganese power batteries are produced by CITIC Guoan Mengli and Shenzhen Lei Tian respectively, and they have been successfully used on large passenger cars. At the 2008 Olympic Games, The technical coach is a modern coach dedicated to picking up and dropping off athletes in the stadium, showing the glory of the Chinese Science and Technology Olympics. ^[2]