energy density of power lithium-ion battery -Lithium - Ion Battery Equipment

What is the energy density of power lithium-ion battery? -Lithium - Ion Battery Equipment

What is the energy density?

First, let's simply understand what the battery energy density is. There are two types of energy density: weight energy density and volume energy density. At present, the most referenced is weight energy density. Its calculation formula is: weight energy density=battery capacity× Discharge platform/weight, in Wh/kg (watt hour/kg); The calculation method of bulk energy density only needs to change the weight of the above formula into volume, in Wh/L (watt hour/liter).

In simple terms, energy density is an evaluation of battery storage capacity. At first, this evaluation was not used to measure the quality of electric vehicles, but the policy requirements for the company's lithium battery storage capacity. According to the requirements, the specific energy of the single power lithium battery of the company will exceed 300 watt hours/kg in 2020, and the specific energy of the system will strive to reach 260 watt hours/kg. From the marketing point of view, since this is the standard for policy formulation, it must have certain attraction for consumers, so it has become a gimmick in the sales process of some pure electric vehicles.

The evaluation of energy density is not yet fully mature

At present, the evaluation of energy density is not absolutely fair, because it is directly linked to the interests of automobile enterprises. As we said before, energy density will be required in policy, and energy is also one of the reference standards in support of new energy. The higher the energy density, the more subsidies for new energy. This has led to an arms race among some car companies in the field of power lithium batteries, and there are still many problems.

To understand how car companies can improve energy density, we should start from the formula: weight energy density=battery capacity× Discharge platform/weight. To increase the final value of this formula, there are two most direct methods: one is to increase the battery capacity, and the other is to reduce the battery weight.

The way to increase the battery capacity is a conscientious approach. There are many ways to increase the capacity, and the most important is to start with the battery material. At present, the ternary lithium-ion battery is the highest type of power lithium battery in China, while the proportion of lithium iron phosphate battery has dropped very quickly. However, no matter how conscientious it is, it can't do any good if it falls into the hands of the wrong person. In order to increase the battery capacity, some manufacturers have lowered the requirements for battery stability, and the security risks have increased. So some insiders worry that the rush for quick success and instant benefit in battery capacity may affect the safety of electric vehicles.(Lithium - Ion Battery Equipment)

Another way is to reduce the overall weight of the whole power lithium battery, which is actually to cure the symptoms rather than the root cause. Some high-quality power lithium batteries have a separate cell for each battery pack, so that the failure will not affect the entire battery pack. These cells are the first to reduce the weight of power lithium batteries. Either develop new materials to reduce the weight without affecting the protection of the battery, or directly cut down the materials or replace them with lighter but weaker materials.

Therefore, there are many ways to increase energy density. For car companies, cutting materials is a win-win method, and the safety problem is, of course, 60 million years old. In the absence of uniform requirements for the structure and materials of batteries, consumers have no way to measure whether the safety and quality of power lithium batteries with high energy density are qualified, good or excellent.

In fact, the simplest and most brutal way to measure the range of electric vehicles is to look directly at the total capacity of the battery. If we need to consider the factors of battery safety and vehicle quality, in the current overall environment of low technology openness and high manufacturing costs, electric vehicles are still worth every penny. To be frank, in general, it is the price of the car that determines the quality. If the relevant parts can improve the fairness of various evaluation standards for electric vehicles, it will have a very positive role in stimulating technological progress and protecting the rights and interests of consumers. Nowadays, smart phones are developing rapidly, and we can see that the fastest growing components of smart phones are the processor and screen of mobile phones. From a single core to the current eight cores, the screen has developed from the previous 480P resolution to the current 2K or 4K resolution, which only takes a few years.



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