The development of lead-acid battery technology has remained largely unchanged for 100 years. Although there have been improvements in chemistry and structure, there is a common factor in causing battery failure. The cause of this failure is the result of the failure of sulfate deposits on the plates, and the most effective way to solve these problems is to apply pulse technology. Pulse technology helps to eliminate these battery faults, it can maintain a high active substance reaction, balance the battery inside, and easily accept external charging. In this way, various related costs due to the replacement of the battery are saved. Second, the technical introduction Experts predict that lead-acid batteries will continue into the next century as the first position in the field of battery power. However, the problem worthy of attention is that the working status of most batteries cannot meet the needs of today's technologically advanced vehicles. It is said that the reaction materials of lead-acid batteries can last for 8 to 10 years or longer, but in fact they cannot. The average battery life is now 6-48 months. Only 48% of the batteries can be used for 48 months. Most batteries are prematurely aging and fail. The cause of a series of problems affecting battery life is the accumulation of sulphate, and the most effective way to solve these problems is by pulse technology. As early as 1989, there was the first patent, which used pulse technology to improve the usability of the battery and extend battery life. Its working principle: the battery always maintains a high active substance reaction, so that the battery is internally balanced and easy to accept charging. This technology provides a large discharge capacity, accepts fast charging, and is durable to use. (In other words, extend battery life) Now let's take a look at how pulse technology benefits the battery and what it works. First let us revisit the working principle of the battery: According to the 11th edition of the International Battery Council Handbook: "The battery is a design of electrochemical principle. The energy generated by the battery is converted by the stored chemical energy. In vehicles and power machinery A battery is needed, and its three main functions are: (1) Power is supplied to the ignition system to start the engine. (2) Power the electrical equipment outside the engine. (3), to the electrical system to play a voltage regulator, so that the output is smooth and reduce the high voltage of the electrical system. †The battery consists of two different materials (lead and lead dioxide). These two materials are placed in a sulfuric acid solution to generate a voltage. During the discharge process, the active material on the positive lead plate and the sulfate of the electrolyte form PbSO4. At the same time, the active material on the negative electrode plate also forms PbSO4 with the electrolyte sulfate. Therefore, as a result of the discharge, the positive and negative plates are covered with lead sulfate (PbSO4). The battery is recovered by charging it in the opposite direction. During the charging process, the chemical reaction state is basically the reverse reaction of the discharge. At this time, the lead sulfate (PbSO4) on the positive and negative plates is decomposed into the original state, namely lead and sulfate, and the water decomposes the "H" and "O" atoms. When the separated sulfate is combined with "H", it is reduced to Sulfuric acid electrolyte. From the above, the basic principle of the operation of the battery is the energy formed by the chemical reaction process of sulfuric acid and lead ion exchange. During the energy exchange process, the reaction product, lead sulfate, is "temporary" on the plates. However, it is worth noting that during the charging and reduction process, the lead sulfate on the electrode plate cannot be completely dissolved and stacked on the electrode plate. This deposit is the remainder of the electrochemical reaction and occupies the position of the plates. That is to say, the effective reactive materials of the plates are continuously decreasing, which is the main cause of battery failure. (The battery is ineffective due to lead sulfate. The common name for this phenomenon is - plate salinization) Plate salting problem: Most battery failures are attributed to the accumulation of lead sulfate. When the energy of the lead sulfate molecules is greater than a limit low, they dissolve from the plates and return to a liquid state. Then they can accept recharging. In reality, however, a portion of the sulfate is not returned to the electrolyte, but is attached to the plates, eventually forming insoluble crystals. Sulfate crystals are formed in such a way that the core energy of these individual sulfate molecules that cannot participate in the reaction is in an extremely low state, which gradually adsorbs other sulfate molecules which are extremely low in energy. When these molecules are stacked and tightly bound, a crystal is formed. This crystal does not dissolve efficiently into the electrolyte. The presence of these crystals occupies the position of the plates, causing the plates to lose their ability to charge and discharge. Therefore, the point or part of the plate that is covered is equivalent to a dead point. According to the BCI manual, page 58: "The essence of the battery is chemical equipment. Its charging characteristics are often changed by the chemical changes of the battery itself. For example, sulfate should be a normal chemical reaction product, but under abnormal conditions. It becomes a superfluous substance and becomes a major problem affecting the chemical reaction, and these excess sulphate accumulates on the plate and is ignored for a long time. In addition, the new battery may be in this state if it is stored for too long. When the battery is severely salted, it cannot accept the fast and full recharge of the generator. Similarly, it can not be satisfactorily discharged. As the salinization increases, it eventually fails because the battery cannot accept charging and discharging. On page 56, “The charging voltage is affected by factors such as temperature and electrolyte concentration, the area of ​​the electrolyte contact plate, the age of the battery, and the purity of the electrolyte. The salinization crystal on the plate is very hard, which increases the internal resistance. ." More than 80% of the batteries are ineffective due to the accumulation of these salinized crystals. The speed, area and hardness of these crystal formations are closely related to time, battery state of charge, and the life cycle of the energy reserve. The accumulation of salinated crystals on the battery is very troublesome. Salting is inevitable in the following situations: 1. The battery has been stored for a long time before being installed and used. In fact, once the battery is added with sulfuric acid, a chemical reaction begins to produce a salt. Therefore, the shelving of the new battery will also be salted, resulting in the failure of the new battery installed soon on the transportation vehicle. 2. The vehicle does not work for a long time. 3. The battery is eroded to increase the internal resistance during charging, causing insufficient charging. 4. Continue to over discharge. 5. Temperature influence. For example, when the temperature turns hot, the rate of salinization increases by a factor of 2 with every 10 degrees increase in temperature. During charging, if the outside temperature is high, when the temperature of the battery reaches 75 degrees, the internal resistance will increase, resulting in insufficient charging. When the temperature turns cold, the vehicle's lubricating oil becomes thicker, which requires more power to start the vehicle, that is, it requires more battery discharge capability. As a result, the accumulation of the salt on the plate is accelerated. If you pay attention to the battery over-discharge, you know that the battery electrolyte is solidified at this time, which greatly damages the plate. Under normal circumstances, when the charge reaches 100%, the specific gravity of the electrolyte is about 1.27. At this time, the solidification temperature of the electrolyte is -83 degrees Fahrenheit; when the specific gravity is about 1.2, the solidification temperature is -17 degrees Fahrenheit; if the specific gravity is 1.14 ( Also called full discharge), then it only solidifies at 8 Fahrenheit. 6. In the case of insufficient charging, the battery cannot supply the maximum starting current, which often causes dead fire to frequently used vehicles. According to the BIC manual, “When a battery is fully charged, it is possible to make the engine slow and idle to start and consume power. In turn, the battery does not get the generator to charge at the optimum speed. As a result, although the battery is charged all day, the battery is still not fully charged, and the battery is often insufficiently charged, and the battery is salinized. This vicious cycle continues, eventually causing the battery to completely fail. In summary, sulphate is inevitable in the energy conversion process, but the crystallization of sulphate is indeed a serious problem, not the sulphate itself, which requires more people to understand the seriousness of this problem - sulphate crystallization Invalidate the battery. The phenomenon of failure includes: 1. Plate bending: Somewhere in the plate, sulphate crystals weaken the acceptance of electrical energy, causing somewhere in the battery plate to be overcharged, and this overcharge causes the temperature to rise here, causing the plates here to bend. 2. Salinization causes the reactants of the grid mesh on the plate to fall off, which may cause overcharging and bending of the plates. 3. Short circuit: The internal resistance increases due to salinization, the plate is bent, and the plate of the other polarity is contacted to short-circuit or damage the frame of the supporting plate. 4. The shedding of the active material: the salted crystallized material increases the internal resistance, causing local over-charging, which causes the cracks and cracks of the plates to fall off. Therefore, the application of pulse technology to protect the plates is the most suitable, and also helps to reduce the damage caused by mechanical vibrations of the battery plates. In the past, after the battery was salted, it was considered useless and discarded, or pulled to repair in the distance. But now, pulse technology can solve this problem very well.
"Gravity Die Casting. A permanent mould casting process, where the molten metal is poured from a vessle of ladle into the mould, and cavity fills with no force other than gravity, in a similar manner to the production of sand castings, although filling cn be controlled by tilting the die."
Sometimes referred to as Permanent Mould, GDC is a repeatable casting process used for non-ferrous alloy parts, typically aluminium, Zinc and Copper Base alloys.
The process differs from HPDC in that Gravity- rather than high pressure- is used to fill the mould with the liquid alloy.
GDC is suited to medium to high volumes products and typically parts are of a heavier sections than HPDC, but thinner sections than sand casting.
There are three key stages in the process.
Advantages
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Gravity Die Casting
I. Overview