What are the implications of lithium-ion battery pin?

The lithium-ion battery pin

In the battery output of many mobile phones, in addition to the positive and negative poles, there is usually one or more other output terminals. 

The principle of ID resistor

ID (identification)

In short, the cell phone learns the battery type by reading the resistance value of the pin resistance (according to the resistance value, it can distinguish nickel metal hydride battery from lithium ion battery, and distinguish high-capacity battery from ordinary capacity battery).

TC resistance is just the opposite of PTC resistance. NTC is short for negative temperature coefficient thermistor.

The phone gets the temperature of the battery by reading the resistance value of the resistor to carry out the corresponding protection action. For example, the mobile phone is not charged in the environment outside 0~45 degrees Celsius, and the mobile phone is forcibly shut down outside the range of -20~60 degrees Celsius, so as to protect the dangerous operation in the non-battery tolerance environment.

NTC resistance value and temperature corresponds relation. There is a very definite correspondence between the resistance and the temperature. The resistance can also be used to compensate for negative temperature in some circuits.

A typical lithium-ion battery integrated protection circuit from left to right is the voltmeter circuit/protection circuit/real-time clock.

This is very interesting. One advantage of having the live clock circuit in the battery pack is that even if the battery is unplugged from the phone, the clock will not be lost as long as the battery voltage is not dropped below 3.0V. Now most of the real-time clock circuit is placed inside the phone, only relying on a small capacity of backup battery power, once the phone power, the maintenance time is very limited.

The potential difference between the two poles is called the voltage of the battery. The voltage of lithium ion battery mainly includes rated voltage, open circuit voltage, working voltage and termination voltage, etc.

Rated voltage is the nominal value of the theoretical voltage, represents the design voltage. The theoretical voltage is the maximum of the battery voltage. The theoretical voltage of different materials is different

(2) Open circuit voltage refers to the open circuit voltage refers to the potential difference between the positive and negative poles when the battery has no current, that is, refers to the voltage at both ends of the positive and negative poles when the battery does not work. For example, the open circuit voltage of lithium ion battery is generally about 3V, and the sodium ion battery will be below 3V.

(3) Working voltage refers to the voltage at both ends of the battery at work, that is, the actual voltage of the battery. In general, the actual voltage is less than the open circuit voltage, because the battery needs to overcome polarization and internal resistance when working.

(4) Termination voltage: termination voltage refers to the maximum charging voltage and minimum discharging voltage specified in the process of battery charging or discharging. If the voltage is lower than the termination voltage of the discharge, the battery continues to discharge, the voltage at both ends of the battery will rapidly drop, forming a deep discharge, so that the products formed on the plate in the normal charging is not easy to recover, thus affecting the life of the battery. Why do lithium-ion batteries have voltage platforms?

Gibbs phase law, where the degree of freedom is zero for two opposite phases, the chemical potential is constant, and there is a voltage platform and the voltage platform is divided into two definitions: 1, The intermediate value of voltage at two inflection points in a discharge curve. If the first inflection point is 3.8v and the second inflection point is 3.6v, then the discharge platform is 3.7v, or the discharge platform of the battery is 3.6v ~ 3.8v, represented by the range value.2, The voltage at 50%DOD, also known as the median voltage.

Pin, also known as Pin, is called Pin in English. Is from the integrated circuit (chip) internal circuit leads to the wiring with the peripheral circuit, all the pins constitute the chip interface. A segment at the end of a lead forms a solder joint with a pad on a printed board by soft brazing. The toe can be divided into bottom, toe and side.

In the early cell phone battery, T foot was used to connect negative coefficient thermistor (generally 10K), and it was directly connected to the battery protection plate, without any relationship with the battery protection circuit. The original design is to calculate the battery capacity (discharge and charging of lithium battery is related to temperature) by changing the battery temperature, which leads to the change of thermistor (the higher the temperature, the smaller the resistance value), so as to better indicate the battery capacity.

Some early batteries also have a D foot, which is generally connected to the common patch resistance, MOTOROLA mobile phone is generally connected to a recognition IC, this foot is also basically direct to the ground, this foot is used to identify whether the battery is correct, the current mobile phone battery is basically not used this.

Now the battery T foot is generally directly connected to a patch resistance to the ground, resistance is no more than 10K\100K and other common.

This foot is useless if charged with a universal charger. And your original charger cannot identify, which means that it has such a recognition item, and is relatively high-grade. At least it has a comparison circuit.

The page contains the contents of the machine translation.