Battery knowledge

1. What is the lithium battery:

Lithium battery mainly refers to the use of lithium element in the electrode material as the main active substance of a type of batteries. In this definition, it refers to a class of lithium batteries, including lithium primary battery and a lithium secondary battery. Primary battery can not be charged is reused, the secondary battery can be charged and discharged repeatedly used. Lithium primary batteries are lithium manganese batteries, lithium-sulfur batteries (of course there are the secondary lithium-sulfur battery), lithium thionyl chloride batteries, lithium thionyl chloride batteries. Watches, calculators, computer motherboard CMOS lithium batteries used in dog day, mainly lithium manganese battery. Other primary lithium batteries in the civil seems rare. We usually refer to lithium batteries, lithium batteries, such as mobile phones, notebook lithium battery, lithium secondary batteries belong. Lithium secondary batteries have many, but the most common lithium ion secondary batteries, called lithium ion batteries.

2. The lithium-ion battery history:

Historical lithium-ion batteries is very short, from around 1990 SONY Since the launch of the first piece of Carbon as lithium battery cathode materials, but also has more than ten years of history. Lithium-ion batteries are now on the market there are two, one for liquid lithium-ion battery, usually steel or aluminum packaging; the other is a polymer lithium ion battery, lithium polymer battery for short, usually plastic composite film package.

Lithium-ion batteries in the structure there are five main blocks: the positive electrode, negative electrode, electrolyte, separator, electrode leads and the housing.

3. The primary difference between batteries and other secondary batteries?

Another obvious difference is their energy and load capacity, as well as self-discharge rate, a secondary battery power than the primary battery is high, but their load capacity is relatively small.

What are the advantages and disadvantages of Li-Ion battery 4. The yes?

Rechargeable battery life is longer, it can be recycled more than 1000, although the price is more expensive than batteries, but if often used, is more cost effective. Rechargeable battery capacity is lower than the same size alkaline manganese batteries or zinc-carbon batteries, for example, they discharge faster.

Another drawback is due to their nearly constant discharge voltage, discharge is difficult to predict when the end. When the end of the discharge, the battery voltage will suddenly decrease. 5. If the rechargeable batteries in the camera is how to achieve its energy conversion?

Each battery has a capacity of electrochemical conversion, coming stored chemical energy directly into electrical energy, the secondary electrons (also called battery) in terms of (another term, also known as portable rechargeable battery so), in the discharge process , it is to convert chemical energy into electrical energy; while in the charging process, in turn reconverted into electrical energy to chemical energy. This process electrochemical systems, and can be charged and discharged more than 500 times, and our products li-ion can be repeatedly charged and discharged more than 1,000 times. Li-ion is a new portable rechargeable battery. Its rated voltage of 3.6V, its discharge voltage will gradually decline with depth of discharge, unlike other rechargeable batteries, as in no discharge, sudden drop in voltage.

6.Li-ion batteries which of these parts?

  (1) Battery cover down

  (2) positive electrode - active material is lithium cobalt oxide

  (3) the diaphragm - a special composite film

  (4) a negative electrode - active material is carbon

  (5) an organic electrolyte solution

  (6) of the battery case (divided into two kinds of steel and aluminum)

7. What is the charge limit voltage? Rated Capacity? Rated voltage? Termination voltage?

A, charging voltage limit: according to manufacturer provisions, the battery voltage constant current charging into the constant voltage charging time.

B, rated capacity of manufacturers indicated battery capacity refers to the battery at an ambient temperature of 20 ℃ ±

At 5 ℃ for 5h rate of discharge to the termination voltage of electricity to be provided with C5 expressed in units of Ah (ampere hour) or mAh (milliamp hours).

C, nominal voltage: battery voltage to represent an approximation.

D, termination voltage: predetermined discharge termination voltage of the battery load, the value n * 2.75V (single series of lithium-ion batteries using only the number of "n" represents).

8. Why constant charging current is gradually reduced?

Because the process is terminated when a constant current, internal battery electrochemical polarization and then again kept constant throughout the same level, constant process, and then a constant electric field, internal Li + concentration polarization gradually eliminated, the number of ion migration and gradually reduce the current speed performance

Use, the battery suddenly put out of power, it had to be terminated. On the other hand rechargeable battery can provide a battery capacity is higher than the part too. However, Li-ion batteries but it can be widely used in photographic equipment, because of its high capacity, high energy density, as well as the depth increases with decreasing discharge voltage discharge

9. What is the capacity of the battery?

The rated capacity of the battery capacity and the actual capacity of the points. Battery capacity rating refers to the provisions of the design and manufacture of battery or guarantee the battery under certain discharge conditions, should release a minimum amount of power. Li-ion battery in a predetermined normal temperature, constant current (1C) constant voltage (4.2V) Charge 3h charging controlled conditions, the actual capacity of the battery is the actual capacity of the battery under certain discharge conditions evolved, mainly due to discharge rate and the effect of temperature (hence, strictly speaking, the battery capacity should be specified in the charge and discharge conditions). Common units capacity: mAh, Ah = 1000mAh).

10. What is the internal resistance of the battery?

It refers to the battery at work, current flows through the battery internally by the resistance. Consists of ohmic resistance and polarization resistance in two parts. Battery internal resistance, the battery will result in lower operating voltage discharge, the discharge time is shortened. Material is mainly affected by the size of the internal resistance of the battery manufacturing process, cell structure and other factors. It is an important parameter to measure the performance of the battery. Note: In general charging state resistance as the standard. Battery internal resistance measurement needs special resistance measurement, rather than using a multimeter ohm range measuring.

11. What is the open circuit voltage?

That means that the battery circuit no current is flowing in the non-working state, the potential difference between the positive and negative battery. Under normal circumstances, Li-ion fully charged open circuit voltage of about 4.1-4.2V, after opening the discharge pressure of about 3.0V, through the open-circuit voltage of the battery, it can determine the battery state of charge.

12. What is the operating voltage?

Also known as the terminal voltage means the battery circuit that is obsolete in the current battery positive and negative electric potential difference between the working state. In the battery discharge operation, when the current flows through the inside of the battery, the battery does not need to overcome the resistance caused by the resistance, so the work is always lower than the open cell voltage, charging the opposite. Li-ion discharge operating voltage of about 3.6V.

13. What is the (discharge) rate? Time rate?

Refers to the battery discharged current value of its rated capacity when needed within a specified period of time, which is equal to a multiple of the rated capacity of the battery in the data value, usually with the letter C. The battery's nominal rated capacity of 600mAh to 1C (1 magnification), 300mAh was 0.5C, 6A (600mAh) to 10C. And so on. When the rate known as hour rate, refers to a constant current battery fully discharge its the number of hours required for the rated capacity. the battery is rated capacity of 600mAh, 600mAh to fully discharge its current rated capacity of 1 hour, said 600mAh of current of 1 hour rate, and so on.

14, what is the rate of self-discharge?

Also known as charge retention ability, it refers to the battery in an open state, the battery storage of electricity under certain conditions, to maintain the ability to influence mainly by the battery manufacturing process, materials, storage conditions and other factors. It is an important parameter to measure the performance of the battery.

NOTE: After the battery charge 100% open shelving, a certain degree of self-discharge normal. In GB standard LI-ion after 20 ± 2 ℃ under the conditions of open open conditions hold for 28 days. It allows the battery capacity loss.

15. Common battery charging method, which has several:

1. The constant current charging

A charging process of the charging current is constant, this method is the most common.

2. The constant voltage charging

  Charging a rechargeable power source is maintained across the constant value, the current in the circuit with battery voltage rises gradually decreases.

3. The constant current charging

First, constant current charging to the CC battery, when the battery voltage rises to a certain value, the CV voltage is held constant, the circuit current is reduced to a very small, eventually approaches zero.

First, two kinds of charging often in nickel hydrogen and nickel-cadmium batteries used in lithium polymer battery charging method is generally constant current constant voltage charging: battery is first constant current charging CC, when the battery voltage rises to a certain value when the CV voltage is unchanged, the circuit current is reduced to a very small, eventually approaches zero.

Since the lithium-ion battery energy density is high, it is difficult to ensure the safety of the battery. In the over-charged state, the battery temperature rises excess energy, so decomposition of the electrolyte and gas is generated due to internal pressure to rise and the risk of rupture or produce spontaneous combustion; on the contrary, in the over-discharge state, due to decomposition of the electrolyte and cause the battery characteristics durability degradation, thereby reducing the number of charge cycles.

16. The lithium-ion battery operating temperature range?

 Charging: 0 ~ 60 ℃ (recommended)

 Discharge: 0 ~ 60 ℃ (recommended)

 Storage temperature: 25 ± 5 ℃ (recommended)

Protective plate (PCM) Basics

17. A lithium battery protection circuit:

Lithium-ion battery protection circuit is to ensure the safety of such over-charging and discharging state, and to prevent deterioration characteristic. Lithium-ion battery protection circuit is constituted by the protection of IC and two power MOSFET, in which the protection IC monitors the battery voltage, when switching over-charging and discharging state in order to plug the power MOSFET to protect the battery protection IC features are excessive charge protection, over-discharge protection and over-current / short circuit protection.

BMS Basics

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