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The role and working principle of the diaphragm of lithium battery

Release time:

2024-09-27

The main function of the diaphragm of a lithium battery is to separate the positive and negative terminals of the battery, preventing the two terminals from contacting and causing a short-circuit, and at the same time allowing electrolyte ions to pass through to ensure the normal operation of the battery.

The role and working principle of the diaphragm of lithium battery

The diaphragm of lithium battery is the key inner component in the battery structure, and its performance directly affects the capacity, cycle performance and safety performance of the battery. The main functions of the diaphragm include:

Separate positive and negative terminals: The diaphragm separates the positive and negative terminals of the battery, preventing direct contact between the two terminals and resulting in a short circuit. This is the most basic and important function of the diaphragm.
Allow ions to pass through: The diaphragm has a microporous structure, and these micropores allow electrolyte ions to pass through, while preventing electrons from passing through. This allows lithium ions to move freely between the positive and negative electrodes during charging and discharging, while electrons flow through an external circuit to generate current.
Ensure battery safety: Since the diaphragm material itself is not conductive, its physicochemical properties have a great impact on the performance of the battery. High-quality diaphragms can improve the overall performance of the battery, including safety, capacity, and cycle life.
The preparation process of diaphragm includes two main methods: dry process and wet process:

Dry process: prepared through physical stretching, crystallization and quenching steps, lower cost but poorer diaphragm performance.
Wet process: prepared by thermal phase separation and other steps, diaphragm microporous distribution uniformity, better performance but higher cost.
Different types of batteries according to their needs to choose the appropriate diaphragm materials and preparation process. For example, the field of lithium power battery often use specific composite materials and technologies to optimize the performance of the diaphragm. In short, lithium battery diaphragm is a key component to ensure the safe and efficient operation of the battery.