The Li-Ion rechargeable battery is managed so that it will not occur over-charged or over-discharged status. On the battery management system, there is a primary protection circuit and also the secondary protection circuit that would back up when the primary protection circuit fails. By the double protection circuit, BMS has redundancy and secures safety.

A state in which the primary protection circuit fails is an obvious abnormal and must make disable the battery pack to prevent any risk of danger.

 

The standard circuit scheme of the secondary protection circuit uses a secondary-level voltage monitor IC and a fuse, called three-terminal fuses, signal fuses, and fusing registers. When the voltage exceeds the threshold value of the predetermined voltage and is held for a certain period of time or longer, the fuse cut off the power path and prevent overcharging and over-voltage (See the figure below)

 

 

 

The double protection circuit on BMS is already standard for the notebook PCs, Energy Storage Systems, the large stationary battery systems, UPSs, the electric bicycle, etc. to ensure safety.

In recent years, many rechargeable battery products have the double protection circuit in order to meet the requirements of the safety standards.
Uchihashi  -   Three Terminal Fuse

１．Fuse off the power path physically in overvoltage status

２．Large current and high voltage rating, no required parallel use of the fuse

３．High Reliability and Durability in the battery management systems

 

 

 

 

 

 

 

 

 

 

 

 

From December 20, 2020, manufacturers and suppliers must ensure that their audio/video (AV) devices and information and communication technology components comply with the new EN 62368-1 standard. This new, revised standard contains safety-related regulations and replaces the standards IEC/EN 60065 and IEC/EN 60950-1

This applies both to units in the devices, such as power supply modules, and to external power packs that are simply included with the devices.

 

In order to ensure protection against electric shock, different methods and techniques are described in the new standard. The IEC 62368-1 defines certain high-voltage tests (HiPot tests) depending on the mains voltage used for the device. That is, for example, 1.5kV for 120VAC or 2.5kV for 230VAC. These values ​​are decisive when dimensioning the gas discharge tube between PE and L/N.

 

Likewise, the devices or subsystems to be certified may only have certain residual voltages after being subjected to voltage pulses (surge, eg 1.2/50-8/20μs 6kV) in order to ensure protection against overvoltage. This generally requires gas arresters with ignition voltages triggered by the HiPot test. For these reasons, the arrester is separated from PE during the HiPot test, which means an increased, mostly manual effort.

 

To avoid this, the BXD series gas arrester was specially developed. The HiPot test can be carried out after assembly without any additional effort. At the same time, the requirements for overvoltage protection are met.

 

Key Features

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Technical data and testing results available.