Supporting the infrastructure of modern society must be based on a very high operational reliability. Internet and telecommunications switching center server farms to ensure nearly 100% of the sentence, without run-time “or availability of the system, they rely primarily on a very mature technology – lead-acid batteries , while the center of data storage used in high technology. Typically, these key nodes, and many other important areas are equipped with standby power, the supply of electricity in standby mode is usually the inverter top-level inverter pairs of VRLA (VRLA) battery or a similar benefit, sealed gel cell battery assembly section of energy conversion. ThinkPad T43 battery ThinkPad T60 battery
The reason why traditional techniques are widely used, there are many reasons, including lead-acid batteries affordable, but also with exceptional reliability. But while Great but not perfect. VRLA battery life is limited (generally 12 years of life from conception), often mission-critical systems using the battery as a source of backup power, but changed regularly. Failure may indeed occur. In a typical standby power, the role of the battery as its name – they still maintain a fully charged state to await the primary power failure. And when fully responsible for the prosecution small current through the float “charge to keep. If the float current is below a ceiling, then the battery in the gas produced by electrolysis will be re-chemical combination. In this case, a single voltage battery float is slightly higher than the standard value of 2.27 V, may also damage the battery. A little more tension will cause precipitation of the electrolyte capacity of more recombination more gas, these gases are not handled by the overflow valve. If the battery temperature is too high, even if the charging voltage is appropriate, can lead to loss of electrolytes. XPS M1330 battery XPS M1530 battery
Other methods of early termination of sulfation, columns and very bad network connection, the connection plate to the network and evil, the stratification of electrolyte and a grid to accelerate corrosion. There is still another, if a failure mode low, but catastrophic – thermal runaway, which is peculiar to VRLA gel batteries, and a failure mode can lead to catching fire. The only way to avoid thermal runaway is to control the internal temperature of the battery.
Simply monitoring the battery voltage on the detection of lead-acid battery capacity decline in the role is very limited, it has been recognized in the industry. When the battery performance diminishes, it is usually presented is that the nominal voltage, until the release of large currents can only apparent, but when its capacity has been considerably reduced voltage drop prematurely. By measuring the proportion of electrolyte to determine the condition of the battery accurately, the method of the VRLA or sealed gel batteries do not apply; routine battery of tests used in the only way is to discharge the battery to a state controlled the next, but this approach need to stop using the battery. In addition, the depth of discharge also reduces the battery life of lead-acid; in on a regular basis to conduct its test of the backup battery discharge, and its principal power with high reliability of the system, most programs use this test to determine the battery life. XPS M1730 battery XPS M2010 battery
Recently, continuous monitoring may be a non-interference electronic method of detecting a single cell near the failed state, this method can not only save costs, while maintaining overall system availability. The predecessor of these systems is usually measured cell or battery (battery industry term meaning that the shell in the same package multiple battery) voltage – despite its limitations is well known – with charge / discharge current and temperature ambient. Some systems attempt to guess the extent or strength of the internal battery, its effectiveness varies.
LEM Sentinel system is dependent on basic parameters of a simple analog measurement of change leading product has now become the first of three generations of the Sentinel III. It is tailored in a single chip SoC (System on Chip) IC on the integration of analog and digital technologies. The device configured in a measured terminal voltage, the temperature of the internal battery and internal resistance of the module, can provide accurate measurement results for the cost of new in most of the configuration of the backup system can afford in the budget system is the design of a key. Studio 1536 battery Studio 1537 battery
Battery temperature and / or exponential growth, the value of internal impedance (Figure 1), which are close to the failure of instructions, data recording system to monitor trends in data over time to identify possible approaches fail. All modules are configured Sentinel III with a probe for measuring the outside temperature or the patch can be bound directly to a single cell or battery casing to accurately monitor the battery temperature as much as possible.
Exponential curve means that the failure difficult to detect early, but the last part of the performance degradation very quickly.
The battery is used or is being loaded, you can use a mature technology assessment of the internal impedance. Typically, the float voltage superimposed DC measuring low AC voltage and AC current at that time, and then measure the results of the projection of the internal impedance, the methods of specific implementation are different. However, this method has limitations, it can not cope with a form of the exponential curve. And expiring at the failure process of a single cell in the data recorder of their failure to recognize the trends appeared in good condition, on the contrary, the problems of failure, the battery may be short term be completely ineffective. Studio 1555 battery Studio 15 battery
LEM has developed a more sophisticated algorithm, which can be detected as early as possible is a single cell performance decay. The result is a methods test very reliable, it can completely penetrate the energy of a single layer of cells to ensure maximum reliability. It is commonly called the Randles equivalent circuit, based on the performance of the electrochemical cell from the electrical components of a network circuit, each electrical component consisting of a single cell of an associated physical factors.
Figure 3 shows the battery life of different parameters in one period of the smooth curve. The same features or capabilities during the discharge period of falling has also been confirmed. All the impedance of the equivalent circuit of factors are to follow curves similar fall in the early stages of failure or capacity, no significant change. If the impedance state to a single main 338794-001 361742-001 battery indicator, it will not provide meaningful guidance, unless the volume down more than 25-30%. Because the industry standard is to replace the provisions of the performance has fallen below 80% of cell performance, it is clear that the importance of early identification of possible failure.
However, in the Randles equivalent circuit, there is a parameter in a single battery failure (except for a simple metal corrosion, the parameters of this mode of failure by increasing Rm forthcoming) will start to change, ie CDL-in, double-layer capacitance. Figure 3 below Natiao curves of their properties; In addition, the stage performance in the ordinary course of normal cells, and the assumption that power is fully charged batteries failed, its curved shape is similar Cdl. Studio 17 battery Studio 1735 battery