LEM battery online monitoring method

　　Author ：Iflowpower – Dobavljač prijenosnih elektrana

The use of LEM battery intelligent sensors. The necessity of battery monitoring With the rapid development of my country's communication, electricity, UPS and other industries, the battery's use is also rapidly added. As far as our battery use conditions, some unexpected situations often occur, such as the seemingly normal battery discharge, no electricity.

This situation is noticeable for the operation of the battery without being effective monitoring. Once a piece of battery failure occurs in a battery pack constructed in series in series, it will cause the entire battery pack to discharge. The battery is the last safeguard measures for security uninterrupted power, and it is also the most unsafe factor in uninterrupted power supply system.

From the system theory, we understand that the system's security depends on the most unsafe factor in the system, that is, the "wooden bucket theory" we often quote. Second, the current status of battery monitoring 1. Planability Maintenance The most conventional practice in terms of the maintenance of the battery is to conduct a check-in discharge detection of the battery pack at least every year.

Because if the battery pack is not performed in 3-4 years, the battery pack electrolyte will be hierarchically, that is, the electrolyte is analyzed as a liquid layer which is different from the acid solution concentration, which affects the battery interrupt. Power supply capacity. This phenomenon will eventually result in a major plate corrosion in a region with high sulfuric acid concentration.

However, this planned maintenance is taken because the two maintenance intervals do not continue to monitor the status of the battery; the user does not dare to say that the battery pack will run normally after the second day after the discharge detection is performed. Down; additionally, discharge detection usually consumes several hours or even days, which is a high cost, which has destructive and unsafe process for the battery (including remnant). 2.

By monitoring the battery voltage to monitor the operational mechanism and failure mode of the battery, the relevant standards have been introduced in China, and the necessary devices for battery monitoring are installed in DC power, such as voltage patrol instruments, etc. However, according to the working conditions of the reserve battery, it may not be discharged for a long time. During two regular verified discharge detection, it is also possible to fail, and the end voltage of the battery is completely normal.

As shown below (from IEEE): It can be seen that only test voltages are completely insufficient, and it is easy to mislead the user, and use bad batteries as a good battery, this harm is quite large. Then there is a good way to monitor the state of the battery, and can give a warning signal when the battery performance is lowered to some extent, so that we can replace the battery or specially maintained before the battery failure, thus guarding disasters What happens to the power failure? The answer is affirmed, by measuring the state of the internal resistance of the battery, can effectively predict the degree of deterioration of the battery, which is the ability to monitor the health of the battery SOH (Statusofhealth). As shown below: Yellow trend line Shows the internal resistance of the battery during October to November due to various protrastening sharply, it can be judged that the state of the battery has been severely deteriorated, and it is determined that the battery has failed to fail.

Third, the LEM Battery Monitoring Module Analysis From the above decomposition we can summarize several essential conditions for monitoring batteries: 1) Continue monitoring 2) To monitor single battery monitoring 3) To monitor battery internal resistance LEM for battery The operating mechanism and failure mode have developed the smallest smaller in the world. Sentinel, which can accurately measure the internal resistance, temperature, and voltage of the monomer battery, and operate through the serial communication protocol. Realize continued monitoring of batteries.

As shown in the figure: The conventional parameters of the device are as follows: 1. Measure the voltage of 1.5V-15V, accuracy +/- 0.

5% 2. Temperature error, + / - 2 ° C 3. Measurement of internal resistance +/- 2% 4.

All of the connector is used, the installation is extremely fast. Simple wiring and low engineering costs 2) Independent modules make monitoring very flexible, and relate to aggregated monitoring products more highlights. 3) The module uses a pulse current discharge method to measure internal resistance (see above), discharge current small 12V battery discharge current is less than 2A), not only safe and the battery is not easy to cause injury.

4) Swiss headquarters and RWTH Aachen University's multi-year measurement algorithm, the measured resistance is reliable (see figure below), strong anti-interference ability, five-year warranty: Swiss Lem headquarters for a long time in Germany Aachen Technology Detection, the internal resistance measured by the LEM module is basically consistent with the detection of the detection of the LEM Equipment Eismeter Decomposition. It is possible to simply install, which includes the following components • Sentinel: Measure the voltage, temperature and internal resistance of a single VRLA battery or rich liquid battery, transferred to the data logger S-Box via exclusive bus S-BOX. • Current sensor: current sensor test battery pack status (charge, discharge or floating state).

• S-BusConverter: This module converts the S-Bus protocol to a standard serial output protocol. • S-Box: Data Recording Apparatus with Ethernet interface, used to record the trend and alarm of each Sentinel. • CellViewNet: The visualization software used in conjunction with S-Box, used for graphical display of various data, alarms, and generate various reports.

As shown below: Of course, OEM vendors can use only the Sentinel module supplied by the LEM, and cooperate with their own system to form a battery monitoring system with their own characteristics. These manufacturers can be both UPS manufacturers, or integrators that specialize in developing battery monitoring systems. The Sentinel module of the LEM has been well used in China, especially the power industry, as shown below: In short, the handling method is ideal for current communication, electricity, and UPS backup battery monitoring; believes that the battery monitoring of the LEM will Make a contribution to my country's safety electricity system.

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