Chemical battery applications more widely, the application of these elements will make the battery with more better, more cheaper protection devices.
A, NiCD Battery: low impedance, stable chemical characteristics did not like the NiMH and NiCD battery Li-ION battery overcurrent as less sensitive. However, due to low loss, the application is still widely used. However, in the short-circuit or overcurrent condition, their low internal resistance will lead to a higher current. Usually these are the cause of the malfunction of the battery overcurrent, overheating and not by any battery material application products are applicable.
B, NiMH battery : NiMH batteries than NiCD batteries have higher energy density . When it exceeds 90C , these batteries more degradation. VTP or LTP with more than SRP/LR4 material suitable to protect this type of battery . The design of the battery , SRP and LR4 can protect the battery , but with the LTP, VTP stronger the thermal performance .
C, Li-ION Battery: in all chemical batteries , Li-ION battery energy density of the largest chemical properties of the most sensitive. In use and charging , the need has circuit protection devices. Now commonly used protective device is an integrated circuit , but this is not the most secure , since the integrated circuit itself may cause a short circuit or failure of the protective device CMOS boot unsafe . Time when more than 90C , Li-ION battery will start to degenerate , because of this the maximum battery voltage , so the circuit protection requirements even more stringent . Although LTP, SRP and other series have been used as early as the battery , but the most suitable PTC element VTP; For large -capacity Li-ION battery , LR4 series of actions shorter than the SRP series is more applicable .
1 , resettable fuse applications in rechargeable battery
1 ) , the problem with the analysis : NICD, NiMH, Li-ION commonly used in mobile phones and computers to special protection circuits. These batteries are usually the cause of failure : the positive and negative terminals accidental short circuit ; charger can not stop a fully charged battery ; using the wrong charger or battery polarity reversal. The PTC SMD
Series battery pack installed in series in each unit, which allows the circuit to provide over-current and over-temperature protection.
2 ) , protection requirements : when a failure occurs , the voltage of the mobile phone up to 16V, the voltage of the computer can achieve 24V; its electric current up to 100 amperes. The overcharge condition , the battery pack needs to be over-temperature protection , NiCD battery can not exceed 120C, NiMH and Li-ION batteries can not exceed 90C.
3), PTC resettable fuse
selection : LTP, VTP and LR4 commonly used in mobile phones and cordless phones with high holding current of the SRP, LTP and LR4 series commonly used in desktops and laptop computers . For NiMH battery pack , VTP, LTP material allows designers to increase the thermal conductivity of protection. Some special applications of the patch and VTP series can be used AAA batteries unit.
Summary: As the chemical battery has a low consumption, low impedance , the maximum energy density and low price total number of advantages , making the production and life are widely used. In many applications, it was found that the current is too large will always cause chemical battery explosion , overheating, and other issues. Million Swiss and engineers through failure analysis of customer applications and technologies to overcome found using wh resettable fuse
as a chemical battery fuse can effectively prevent the overcurrent caused by chemical batteries overheating problem, so engineers have combined the characteristics of self-recovery fuse and battery chemistry applications puzzle design a specialized chemical battery overcurrent protection solutions to solve customer problems, above suggestions is chemical battery overcurrent protection.