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Will high energy density of lithium batteries affect safety?

 Will high energy density of lithium batteries affect safety?

What is battery energy density?

Since energy density is called density, it is the same concept as our junior high school physics, which represents the amount of electricity stored in a battery per unit volume/mass. That is to say, if the energy density of the battery is high, in order to achieve the same capacity, it is possible to carry fewer batteries and reduce the weight of the battery; Alternatively, with the same weight, bring more batteries to increase the battery capacity.

What is energy density related to?

The energy density of a battery is basically determined by the positive and negative electrodes of the battery, but only the active materials of the positive and negative electrodes cannot guarantee that the battery can generate electricity. There must be many non active substances, such as conductive aids, adhesives between active powders, isolation films, foil for the negative and positive electrodes, insulation fixing adhesive paper, aluminum plastic film shells or steel aluminum shells, etc.

What does the above paragraph mean? For example, the positive electrode is responsible for producing lithium ions, the electrolyte is responsible for transportation, and the negative electrode is responsible for receiving. The method of improvement is nothing more than: the positive electrode has more lithium ions, the electrolyte has more transport points, and the negative electrode has more reception points, which is a relatively difficult thing to achieve.

Does high battery energy density affect safety?

For current lithium-ion batteries, high energy density means that there are more active lithium ions per unit volume. Lithium ions like to burn, which means that in theory, blindly pursuing high energy density without protective measures can indeed lead to reduced safety.

Introduce several theoretical methods for adding battery safety.

1. Efforts should be made in terms of monomer cells, such as improving positive and negative electrode materials, and adding flame retardants to the electrolyte.

2. From the perspective of PACK, efforts should be made to pay more attention to the relationship between batteries and the usage environment, various battery pack tests, and strengthening protective structures, flame retardant design, overcurrent protection, etc. are all useful methods.

3. Next comes the system control aspects such as BMS. If the first two are to make the battery stronger and more fully equipped, then the strengthening of BMS is to make the battery's brain better.


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