COMMON FAILURE MODES & CAUSES OF ELECTRIC VEHICLE BATTERIES
Semco Infratech Pvt Ltd
Lithium Battery Testing & Manufacturing Equipments Supplier ? Turnkey Automated/Semi-Automated Assembly Line
Introduction
There are several ways in which batteries can fail, often resulting in?fires, explosions, and/or the release of toxic gases (Common Failure Modes & Causes of Electric Vehicle Batteries). Thermal Abuse – Energy storage systems have a set range of temperatures in which they are designed to operate, which is usually provided by the manufacturer.
1.?The direct contact of the positive and negative plates of the battery or is lapped by other conductive substances is called the short circuit of the plate. Short-circuit batteries vary due to short-circuit reasons.?
For example:?if a single grid of a battery cannot hold power due to a serious dendrite short circuit, the voltage will be normal when it is first charged, and after being placed for a period of time, the voltage will gradually approach 11V. The measured voltage may get any value of 11-13V. However, when discharged, the voltage often drops suddenly by 2V; some drop by 10.5V faster, and then other discharge curves are basically equivalent to normal discharge, but the voltage is 2V low, which is a soft short circuit,
2. If it is a hard short circuit, measure the open circuit voltage of the battery, which is generally about 10.5 – 10.7V,
3.?When discharging deep, touch the battery with your hand. In addition to heating, there are also obvious high hot spots in the part,
4.?When charging, the voltage rises very slowly and remains low. The temperature of the electrolyte rises very high and quickly.
Causes of Battery Short-Circuit Failure:
1.?In order to increase the capacity of the battery, the partition of electric vehicle batteries is relatively thinner than that of other batteries. The lead sulfate of the negative plate crystallizes and grows. After charging, a small amount of lead sulfate was left in the partition. Once the partition is reduced to lead, if it accumulates more, the battery will appear slightly short. This phenomenon is called?lead branch bridging. Generate this kind of micro-short circuit, lightly generate the grid voltage backward, and in serious cases, a single grid short circuit.
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2.?The active substances on the plate expand and fall off. Due to the excessive precipitation of the falling active substances, the lower or side edges of the positive and negative plates are in contact with the sediment, resulting in the connection of positive and negative plates.
3.?The welding pole group is formed by the “lead flow” that is not exhausted or assembled. When it is assembled, “lead beans” exists between positive and negative plates. Damage the partition during the charging and discharging process, causing the true negative plate to be connected to a short circuit.
4.?Batteries that are overstocked and not maintained regularly, and when recharged, the plate begins to produce twigs to generate short circuits.
Conclusion
In the case of battery failure, there may not be an apparent sign of the fire phenomenon at the beginning. The battery pack is namely enclosed and may be under the hood or inside the EV body. Hence the fire will likely not be noticed when it is in an early developed stage.
About Semco?-?Established in 2006,?Semco Infratech?has secured itself as the number 1 lithium-ion battery assembling and testing solutions provider in the country. Settled in New Delhi, Semco gives turnkey solutions for lithium-ion battery assembling and precision testing with an emphasis on Research and development to foster imaginative, future-proof products for end users.
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