Homemade library ground wave TV double ring indoor antenna:
The received ground decimeter wave frequencies are currently in the 500-800 MHZ frequency range. If there is a good field strength in the urban area, low frequency and high frequency should be taken into account. This is the best resonance; The frequency center is around 700MHz, which is converted according to the radio propagation speed and frequency. If the center frequency wavelength is about 42cm, then the diameter of the ring antenna should be 13cm, that is, the diameter should be a quarter of the center frequency wavelength of about 42cm. If we think of a 42cm conductor as a ring with a central frequency and wavelength of 42cm, then its diameter should be close to 13cm. If we make a good antenna, we can get twice the result of receiving ground waves with half the effort! Indoor Antenna for TV,Indoor Antenna Walmart,Indoor Antenna Best,Indoor Antenna for Router,Indoor Antenna for Booster Yetnorson Antenna Co., Ltd. , https://www.xhlantenna.com
Efficient and precise laser welding can greatly improve the safety, reliability and service life of automotive power batteries, and will revolutionize the future of automotive power technology. There are many laser welding parts of the power battery, and there are pressure and leakage test requirements. Most of the materials are aluminum, so the welding is difficult and the welding process is more demanding.
Generally speaking, the welding of the power battery casing is mainly in the form of side welding and top welding, which have their own advantages and disadvantages, and the aluminum shell battery is prone to problems such as protrusion, stomata, fraud or the like because of the particularity of the material thereof. The square battery is soldered at the corner and is prone to problems.
Difficulties in the process of power battery welding
Generally, the thickness of the casing is required to be less than 1.0 mm. At present, mainstream manufacturers mainly use 0.6 mm and 0.8 mm thickness depending on the battery capacity. The welding method is mainly divided into side welding and top welding. The main advantage of the side welding is that the internal influence of the electric core is small, and the spatter does not easily enter the inner side of the cover. Since the protrusion may be caused after soldering, this will have a slight influence on the assembly of the subsequent process, so the side soldering process has high requirements on the stability of the laser, the cleanliness of the material, and the matching gap between the top cover and the housing. The top welding process can be welded on one surface, and a more efficient galvanometer scanning welding method can be adopted. However, the requirements for the shelling and positioning of the front process are high, and the automation requirements for the equipment are high.
Aluminum shell power battery welding difficulties
At present, aluminum shell batteries account for more than 90% of the entire power battery. Laser welding of aluminum is difficult, and it will face problems such as bulging on the surface of the weld, porosity, fire, and internal air bubbles. Surface bumps, pores, and internal bubbles are fatal injuries to laser welding, and many applications have to stop or find ways to avoid them for these reasons. Many battery manufacturers will have a big headache in the early stage of research and development. The main reason is that the fiber core diameter is too small or the laser energy setting is too high. There are many factors that cause fire (also known as Splash), such as the cleanliness of the material, the purity of the material itself, the characteristics of the material itself, etc., and the decisive role is the stability of the laser. In the power battery welding, the welding process technician will select the appropriate laser and welding process parameters according to the customer's battery material, shape, thickness, tensile requirements, etc., including the welding speed, waveform, peak value, welding head tilt angle, etc. Welding process parameters to ensure that the final welding effect meets the requirements of the power battery manufacturer
Square power battery is difficult
The square battery is affected by the factors such as the matching precision of the incoming material. The corner is most prone to problems during welding. It needs to be explored according to the actual situation. Adjusting the welding speed can solve such problems. Circular batteries do not have this problem, but subsequent integration into battery modules is more difficult.