Nickel Metal Hydride No. 5 battery

What are the methods to prevent short circuits in Nickel Metal Hydride No. 5 battery?

Lithium-ion batteries are subject to the risk of internal short circuits due to many factors such as material systems and manufacturing processes. Although lithium-ion batteries have undergone strict aging and self-discharge screening before leaving the factory, there is still a certain probability of failure due to process failure and other unpredictable use factors, which may lead to internal short circuits during use. For power lithium-ion batteries, there are hundreds or even tens of thousands of lithium-ion batteries in the battery pack, which greatly increases the probability of internal short circuits in the battery pack. Due to the huge amount of energy contained in the power lithium-ion battery pack, the occurrence of internal short circuits can easily induce malignant accidents, resulting in casualties and property losses.

TE's PPTC and MHP-TA series products provide a possible solution to prevent the occurrence of malignant accidents once a power lithium-ion battery has an internal short circuit. For parallel lithium-ion power lithium-ion battery modules, when one or several batteries have an internal short circuit, the other batteries in the battery module will discharge them, and the energy of the battery pack will rapidly increase the temperature of the internal short battery, which can easily induce thermal runaway and eventually cause the battery to catch fire and explode. As shown in Figure 1.

Conventional temperature detection can tell the IC to cut off the main circuit when the battery heats up, but it cannot prevent the continued discharge inside the parallel battery module. In addition, due to the main circuit being cut off, all the energy of the battery module is concentrated in the internal short-circuited battery, which increases the probability of thermal runaway. The ideal way is to cut off the connection circuit between the battery and other batteries in the module when a battery is found to have an internal short circuit and heats up.

As shown in Figure 2, TEPPTC or MHP-TA series products are assembled on a single battery. When an internal short circuit occurs, the TE protection device can effectively block the connection between the internal short-circuited battery and other batteries in the module, and guard against the occurrence of malicious accidents. For power Nickel Metal Hydride No. 5 battery with a large number of single cells, the internal resistance consistency of batteries and devices is required to be high when they are assembled. Due to its internal bimetallic structure, the device resistance consistency of MHP-TA is very good, which can greatly meet the requirements of the internal resistance of the battery.

The short circuit of lithium-ion power lithium-ion batteries is extremely harmful, so it is essential to do a good job of short-circuit protection of the battery pack. The above two treatment methods can effectively protect the circuit when the battery short circuits.

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