What is the relationship between the capacity and volume of the battery?

This should be the case under normal circumstances. But now because of some problems in the industry, whether the battery supplier or the battery manufacturer will cut corners. It seems that the actual content inside is a bit tricky, and the capacity of many battery tags is false because the customer is unable to identify the capacity.

Capacity (energy) and volume relationship, there is a proper term for volume capacity (energy) density.

There are many types of batteries. Here is a lithium-ion battery:

Whether it is a button battery, a cylindrical battery, a square battery or a soft battery, the capacity of the battery is determined by the quality of the positive electrode and the negative active material that can be utilized in the battery. The capacity of the positive electrode and the negative electrode per unit mass (gram capacity) is limited. Under the premise that the new positive and negative electrodes are not developed, the use of the inactive material can be reduced, and the energy density of the battery can be improved, under the same mass and volume. Provide the capacity of the battery, that is, increase the capacity density. For example, reduce the thickness of the electrode substrate, reduce the thickness of the steel shell and reduce the amount of binder and so on.

Regarding the capacity density, from the above knowledge, you can know:

The same battery type can be increased in volume to obtain a larger capacity, such as cylindrical battery 21700 can achieve 5Ah, smaller 18650 generally achieve 3-4Ah. The square battery has 300Ah and is much larger than 30Ah.

Different battery types, due to different structural designs and different energy densities, can be roughly understood as bulk density, soft pack > square > cylinder, so the specific volume and capacity of the three depends on the specific situation.

In addition to the different shapes and structures, the use, design and manufacturing process of the battery also determine the relationship between capacity and volume. In terms of use, the battery is divided into a capacity type battery and a power type battery, and the name is known to have a higher energy density, that is, a larger volume capacity. At the design level, the level of active material is too poor and the natural energy density is lower. From the level of manufacturing technology, the level of each family is different, low-level manufacturers can not reduce the amount of some inactive materials, and cannot increase the energy density.

Capacity is generally proportional to volume.

Guess you want to know the specific capacity of the battery, it has two kinds, one is the specific capacity, that is, the amount of electricity that can be discharged per unit weight of the battery or active material; the other is the volumetric capacity, that is, the battery per unit volume or The amount of electricity that the active substance can release.

For example, the size of the mobile phone battery is small, so the volumetric capacity is required to be high.

Calculation method of battery capacity (C): Capacity C = discharge battery (constant current) I × discharge time (hour) T.

Conversely: discharge time T = capacity C / discharge current (constant current) I.

For example, if a battery is placed at a constant current of 500 MA (mA) for 2 hours, then the capacity of this battery is equal to 500MA*2H=1000MAH=1AH.

For another example, if a battery is discharged for 5 hours with a current of 5 amps, then the capacity of the battery is 10 AH.

There are two kinds of specific capacity, one is mass-to-capacity, that is, the amount of electricity that can be discharged per unit mass of battery or active material; the other is volumetric capacity, that is, the amount of electricity that can be discharged per unit volume of battery or active material.

There are two kinds of specific capacity, one is mass-to-capacity, that is, the amount of electricity that can be discharged per unit mass of battery or active material; the other is volumetric capacity, that is, the amount of electricity that can be discharged per unit volume of battery or active material. The amount of electricity can be measured in coulombs, in mAh or Ah, or in Faraday.

Mass ratio capacity = capacity / quality

For capacitors, the capacity unit of the capacitor is F (method), and mF, uF, etc. can also be used.

For the battery, the unit of capacity is MAH, that is, the current is multiplied by the time, and Ah (Amp) can also be used.

The unit of mass is g (grams).

Similarly,

Volume specific capacity = capacity / volume

The amount of electricity discharged by the battery under specified conditions (including discharge intensity, discharge current and discharge termination voltage) or the length of discharge time is called battery capacity, and the unit is A·H or A·MIN. A car battery is a reversible DC power source that converts chemical energy into electrical energy and electrical energy into chemical energy. It is connected in parallel with the generator.

It supplies power to the starting system and the ignition system during engine start.

When the engine stops running or runs at a low idle speed, it powers the car's electrical equipment.

When there is a demand for electricity exceeding the output of the charging system, it provides current for a limited period of time.

The battery also absorbs the transient overvoltage in the circuit to keep the voltage of the automotive electrical system stable and protect the electronic components.

If the battery is not used for a long time, it will slowly discharge itself until it is scrapped. Therefore, the car should be started once every certain time to charge the battery. Another method is to pull out the two electrodes on the battery. It is necessary to remove the positive and negative electrode wires from the electrode column. First, unplug the negative wire or remove the connection between the negative electrode and the chassis of the car. Then remove the other end with the positive mark (+). The battery has a certain service life and will be replaced in a certain period of time. The same order should be followed when replacing, but when the electrode wires are connected, the order is reversed, first connected to the positive electrode and then to the negative electrode.

When the ammeter pointer indicates that the storage capacity is insufficient, it should be charged in time. The storage capacity of the battery can be reflected on the instrument panel. Sometimes the power is not enough on the road, and the engine can't start. As a temporary measure, you can ask other vehicles for help. Use the battery on the vehicle to start the vehicle, connect the negative and negative poles of the two batteries, and connect the positive pole to the positive pole. .

The density of the electrolyte should be adjusted according to the standard according to different regions and seasons.

Distilled water or special rehydration solution and nano-carbon sol battery activator should be added when the electrolyte is deficient. Never use pure water instead. Because pure water contains a variety of trace elements, it will have an adverse effect on the battery.

Uninterrupted use of the starting opportunity when starting the car causes the battery to be damaged due to excessive discharge. The correct method of use is to take no more than 5 seconds for each time the car is started, and the interval between starts again is not less than 15 seconds. In the case of multiple starts and still not in the car, you should find the reason from other aspects such as circuit, ignition coil or oil circuit.

Always check the small holes in the battery cover for ventilation when driving daily. If the small hole of the battery cover is blocked, the generated hydrogen and oxygen will not be discharged, and when the electrolyte expands, the battery case will be broken and the battery life will be affected.

Check the positive and negative levels of the battery for signs of oxidation. You can use hot water to constantly pour the wire connection of the battery.

Check the presence or absence of aging or short-circuiting in all parts of the circuit to prevent the battery from being scrapped early due to excessive discharge.

The page contains the contents of the machine translation.