The solar road stud is the traffic safety product that uses the solar panel as the charge device, battery or electric capacitance as the energy storage device and the light of the stud is given out through the LED. According to the demands of the Ministry of Transportation, the pressure resistance of the solar road stud should be over 100KN. The solar road stud is set along the road, and it can be applied to delineate the way at night or in rainy or foggy days. Its visual effect is better than the ordinary road stud, and it is always applied together with the marked lines on the road.
The solar road studs can be divided into two types according to the energy storage device: the solar road stud (battery) and the solar road stud (energy capacitance).
The solar road studs can be divided into two types according to the color of the LED: the solar road studs of red and yellow, and the solar road studs of white, blue and green.
Characteristics of the Solar Road Stud
The reflective brightness of the ordinary reflective stud is only 300-400MCD, but the brightness of the solar road stud can be over 2000MCD, which is 6 to 7 times of the former one, and the high brightness can penetrate rain or fog at night and guide the way effectively for the drivers.
2.Flashing synchronically and giving warnings initiatively
The solar road stud can flash in a certain frequency at night, and the visual of people are more sensitive to changes, so the warning function of the solar road stud is quite strong. Giving out light initiatively can not only avoid interruptions of rain and fog to the greatest extent, but make the drivers get rid of the reliance of light of cars, which will make the visual distance longer and greater. The solar road stud plays key role in rainy or foggy days and it does more in the aspect of eliminating security risks.
The working principle of the solar road studs
The solar panel of the solar road stud absorbs solar energy, which can be transformed into electric energy and stored inside the energy storage device, like battery or electric capacitance, in the daytime, and the electric energy inside the energy storage device can be transformed into light, which can be controlled through the photoelectric switch, at night. The light is given out through the LEDs to delineate the way and guide the sight of the drivers.
The solar road studs can be divided into the embedded type and raised type according to the difference of installation site.
The former one is always installed in the central line, and the latter one is installed in the edge of the road. For the solar road stud installed in the central line should have strong pressure resistance, and the solar road stud can only be embedded underground and only 5mm above the ground; the solar road stud installed in the edge of the road does not have strict demands on pressure resistance, and it can work effectively even raised on the ground.
The solar road studs can be divided into the capacitive type and the battery type according to the difference of the energy storage elements of the solar road studs, and the service time of the former one can be 5 to 7 years, and that of the latter can be 1 to 3 years.
For the embedded solar road studs damage the surface of roads greatly, and the cost of the capacitive solar road studs is high, so the embedded capacitive solar road studs are widely applied in our daily life now.
Characteristics of the solar road studs
There are some characteristics should be paid more attention when choosing a solar road stud. If all those characteristics can meet the standard, the solar road stud will be a qualified one.
1. Pressure resistance
The solar road stud will break into pieces after being cracked by the cars if it cannot resist certain pressure, so the solar road stud must have good performance in pressure resistance. But some cheap road studs have hollow structures, which can decrease the cost. The qualified solar road stud has no difference with the cheap one in outlook, once the unqualified solar road studs are put into use, the quality problem will appear after 3 to 5 months.
There are several ways to increaser the pressure resistance of the solar road stud: first, use the solar panel of PC bullet resistant material to increaser the pressure resistance of the electronic part; second, use to IC control to decrease the volume of the electronic circuit to decrease the pressure on the electronic part; third, design some strengthening ribs on the shell of the solar road stud to share the pressure on the electronic part.
2. Sealing performance
If the solar road stud is not sealed perfectly, the water will penetrate into them, which will cause short circuit, which will bring disastrous consequence, so a qualified solar road stud must have perfect performance in sealing.
There are several ways to increaser the sealing performance of the LED solar road stud:
separation design. Adapting separation design on the LED lampshade and the inside electric circuit panel, even the LED lampshade is out of work, the inside part of the solar road stud can be sealed perfectly.
Using the neutral adhesives to guarantee the solar panel, LED lampshade and the shell of the stud can be connected tightly.
The solar road stud can guide the drivers through automatic illumination, and only when the brightness reaches 2000MCD, the solar road stud is qualified. However, the reflective road stud can only give out light through the reflection of the light of the vehicles, which is lower in lamination quality than the solar road stud.
Service time of the battery: the key factor that determines the service time of the solar road stud is the service time of the battery, so it is quite important to choose a suitable battery. Now there are two types of battery can be applied on the market, one is that battery that the capacity decreases to 50% after 500 times charge & discharge, and the other is the battery that the capacity decreases to 70% after 1000 times charge & discharge.
The battery should not only has long service time, but can work in a large temperature range. The chemical substances are set inside the battery, if the temperature is too high or low, the battery will out of work. The working temperature range of the battery of the solar road stud should be I accordance with the practical working environment. The demand on the working temperature range of national ministry of transportation is -10℃ to 50℃, however, the real environment is out of this range, which asks high for the performance of the battery.
Electronic circuit: the design of the circuit board should follow the principle of simple and effective, and there is no need to make it complicated, for one more circuit will raise the possibility of the fault. The electronic devices should be chose strictly, for every fault of the electronic device will cause break down of the whole system.
Welding: the welding of the solar road stud must be firm. For the solar road studs resist crash and crack of the vehicles all the time, a little loose of the welding point will cause the fall off of the circuit. The high quality products should be used in welding to ensure the firm of the welding point and to make it can work for a long time in severe condition.
Solar panel: the solar panel can absorb solar energy directly and it can transform the solar energy into electrical energy, so this is the first link in the whole system of the solar road stud. The working efficiency of the solar panel determines that of the solar road stud directly. Now the monocrystalline silicon solar panel is widely used, for it has high photoelectric conversion rate, which is almost 14%, which can transforms the solar energy into electrical energy to the greatest extent to ensure the energy supply in the working time of the solar road stud. in addition, the solar panel must be hard and anti-friction. For it should resist the crash of wheels energy, if the solar panel is not hard enough, it is easy to be destroyed, which will influence the conversion rate of the solar panel.
5.The matching performance of the battery
The rated capacity of the battery can satisfied the needs of illuminating for 72 hours if set under the testing condition for 8 hours. Even the solar illuminance is less than 1000LX, the rated capacity of the battery should be illuminating for 12 hours after 8 hours’ charge. If the matching performance of the battery is poor, the solar road stud cannot give out light in rainy days and it will out of practical value. And this is the limitation of the solar road stud whose energy storage device is electric capacitance. This type of solar road stud has strict demands on working environment, and it not only need strong sunlight, but should work without continuous rainy or cloudy days.
6.Environmental adaptation performance
The application environment of the solar road stud in complicated, and the application temperature and humidity are different. All of these will influence the normal work of the solar road stud, so the environmental adaptation performance should be taken into consideration in the design of the solar road stud.
Now the Ministry of Transportation notes that the working temperature of the solar road stud should be in the range of -20 to 85℃, and three experiments should be carried out in the temperature between 20 to 60℃ to know whether the solar road stud can adapt the demand of the environment. The Ministry of Transportation regulates that the solar road stud should work effectively after 48 hours testing in the condition of 45℃ and relative humidity of 98%.
The environmental adaptation performance of the LED solar road stud is a comprehensive testing for the mechanical performance and electronic performance of the stud, which involves the aspects of structural design, electric circuit design and electronic device performance, even it production engineering. This asks that all aspects should be perfect to guarantee the solar road stud has good environmental adaptation performance.