Monitoring application of LEM smart battery

With the rapid development of China's communications, power, UPS and other industries, the use of batteries is also increasing rapidly. Under the current conditions of battery use, some unexpected situations often occur, such as seemingly normal batteries cannot discharge electricity when discharged. The main reason for this situation is that the operating status of the battery is not effectively monitored, which leads to the failure of one or more batteries in the battery pack and is not sorted out in time, which in turn causes the entire battery pack to fail to discharge normally. As

the last safeguard for safe and uninterrupted power supply, the battery is also the most unsafe factor in the uninterruptible power supply system. From system theory, we know that the safety of the system depends on the most unsafe factor in the system, which is the "barrel theory" we often quote.

For the operating mechanism and failure mode of the battery, relevant standards have been issued in China, and necessary devices for battery monitoring, such as voltage patrol meters, are installed in DC power supply occasions. However, according to the working conditions of the backup battery, it may not be discharged for a long time, and it may also fail during the two regular verification discharge tests, while the terminal voltage of the battery is completely normal. As shown in the following figure (IEEE):



It can be seen that only detecting voltage is not enough, and it is easy to mislead users to use bad batteries as good batteries, which is quite harmful. So in addition to monitoring voltage, is there any good way to more effectively monitor the state of the battery, and give early warning signals when the battery performance drops to a certain level, so that we can replace the battery or perform special maintenance before the battery fails, thereby avoiding catastrophic power outages? The answer is of course yes. By measuring the state of the internal resistance of the battery, the degree of battery degradation can be effectively predicted, that is, the battery's health state SOH (Status Of Health) can be accurately monitored. As shown in the following figure:



The yellow trend line shows that the internal resistance of the battery rose sharply from October to November due to various reasons. Therefore, it can be judged that the state of the battery has been seriously deteriorated. After discharging the battery, it is confirmed that the battery has indeed failed.

LEM has developed the world's smallest and highly integrated intelligent battery sensor Sentinel for the operating mechanism and failure mode of the battery. It can accurately measure the internal resistance, temperature, voltage and other parameters of the single battery.

The device has the following main features: 1. Measuring voltage 1.5V-15V, accuracy +/- 0.5%

2. Temperature error, +/- 2℃

3. Internal resistance measurement repeatability +/- 2%

4. All connectors are used, and installation is extremely fast

5. <3mA in power saving mode

6. 5-year quality assurance

With the full set of solutions provided by LEM, users can form a perfect battery monitoring system in a very short time.

As shown in the figure:



This solution is very suitable for current communications, power and UPS backup battery monitoring. The system has a good application in Europe and other countries. As shown in the figure:

I believe that LEM's battery monitoring products will make due contributions to China's safe power system.