Reverse-Voltage Chemical Switches in Lithium-ion Batteries
- Baba Mulani
- Dec 18, 2022
- 2 min read
A reverse-voltage chemical switch is a unique feature found in some battery cell designs. It is an essential component that helps to protect the battery from damage due to reverse polarity or over-discharge.
In a normal battery cell, the positive electrode is connected to the positive terminal of the device, and the negative electrode is connected to the negative terminal. When the device is turned on, the battery cell produces electrical energy by the flow of electrons from the negative electrode to the positive electrode through an external circuit. This process is known as discharging.
However, if the battery is connected to the device in reverse polarity, that is, the positive terminal is connected to the negative electrode and vice versa, the flow of electrons will be reversed. This reverse flow of electrons can cause irreversible damage to the battery cell, leading to leakage, swelling, or even explosion.
To prevent this, some battery cell designs incorporate a reverse-voltage chemical switch. This switch is typically made up of two layers of materials that are separated by a thin insulating layer. The first layer is the electrochemical layer, which is made up of a material that can undergo an electrochemical reaction when a voltage is applied in the opposite direction. The second layer is the protective layer, which is made up of a material that can act as a barrier to prevent the electrochemical reaction from spreading throughout the battery.
When a reverse voltage is applied to the battery cell, the electrochemical layer undergoes a reaction that creates a barrier between the positive and negative electrodes. This barrier prevents the flow of current, protecting the battery from damage. The protective layer also helps to prevent the electrochemical reaction from spreading throughout the battery, further enhancing its safety.
Reverse-voltage chemical switches are commonly used in battery cells for applications where reverse polarity or over-discharge is a possibility, such as in automotive batteries, uninterruptible power supplies (UPS), and portable electronic devices. By incorporating this feature into battery cell design, manufacturers can ensure the safety and reliability of their products, preventing damage to the battery and the device it powers.
