From the perspective of food nutrition, energy density refers to the energy contained in each gram of food, which is closely related to the moisture and fat content of food. Foods with high moisture content have low energy density, while foods with high fat content have high energy density.
Energy contained in unit volume, unit: Joule/m3, kilojoule/m3, megajoule/m3, dimension m (L- 1) (T-2). It is used to measure the most suitable battery and compare the amount of electricity stored in a unit volume battery. The heat of gas combustion (measured by volume) is essentially the energy density.
Electric energy released per unit volume or mass of a battery. Generally, the energy density of lithium-ion battery is 2.5 times that of nickel-cadmium battery and 1.8 times that of nickel-hydrogen battery at the same volume. Therefore, at the same discharge rate, lithium-ion batteries will be smaller and lighter than nickel-cadmium batteries and nickel-hydrogen batteries. Battery energy density = discharge rate × discharge platform/battery thickness/battery width/battery length.
The capacity of each lithium battery is a certain amount in a certain period of time, and the discharge rate of lithium batteries means that the discharge amount is several times that of conventional discharge in the same period of time compared with conventional discharge. Generally speaking, for the energy that can be released under different currents, the battery needs to test the discharge performance under different constant currents.
For a single battery, then three-dimensional measurement is enough. For batch batteries, all three dimensions need to be calculated according to the maximum thickness/width/length of batch batteries. Similarly, for batch batteries, the capacity needs to take the minimum capacity of product A or the minimum capacity allowed by this batch of batteries.
In fact, the calculation of energy density is far less accurate than that of capacity density. Customers always want capacity, and energy density is related to cathode materials. The ternary platform is low, but the discharge platform will not be low when calculating the energy density. Bottom line: Energy density is not what customers need, and it is not as accurate as capacity density, so the reference value of energy density is not too great.