The advantages of lithium-ion batteries we often talk about are for traditional nickel-cadmium batteries (Ni\/Cd) and nickel-metal hydride batteries (Ni\/MH). They have high operating voltage, long cycle life compared to energy, and self-discharge rate. Low, no memory effect and other advantages.

The most critical thing for charging lithium batteries is these 3 steps:

The first step: judge the voltage <3v, precharge="" first,="" 0.05="" c="">

Step 2: 3 v <4.2v, determine="" constant="" current="" charging="" 0.2="" c1="" c="">

Step 3: Voltage>4.2v, constant voltage charging, the voltage is 4.20v, the current decreases as the voltage increases, and it is judged to be fully charged.

1. Lithium battery

1. Briefly describe lithium batteries and working principles

Since its advent in 1990, lithium-ion batteries have been rapidly developed and widely used in society due to their excellent performance. Lithium-ion batteries have quickly occupied many fields with incomparable advantages compared with other batteries, and have become well-known for mobile phones and laptops. , small cameras, etc.

The now recognized basic principle of lithium batteries is the so-called "rocking chair theory". The charging and discharging of lithium batteries does not achieve electron transfer through traditional methods, but changes energy through the entry and exit of lithium ions in the layered material crystal. In the usual inrush During discharge, the entry and exit of lithium ions generally only causes changes in the interlayer distance and does not cause damage to the crystal structure. Judging from the reflection of inrush discharge, lithium-ion batteries are ideal reversible batteries. Since lithium ions are in the The positive and negative electrodes of the battery reciprocate, swinging between the positive and negative electrodes like a rocking chair, so some people call the impression of lithium-ion batteries a rocking chair battery.

The advantages of lithium-ion batteries that we often talk about lie in the previous nickel-cadmium batteries (ni\/CD) and nickel-metal hydride batteries (ni\/MH). They have the advantages of high operating voltage, high specific energy, long cycle life, low self-discharge rate and no memory effect. .

2. Common sense in daily use of lithium batteries

(1) Misunderstanding: "The battery is activated and lasts more than 12 hours on the first 3 charges.

Regarding the "activation" issue of lithium batteries, it is said that the charging time must be more than 12 hours, and it must be repeated three times to activate the battery. This statement that "the last three times of charging took more than 12 hours" clearly clarifies the charge from nickel batteries (Nickel cadmium and nickel metal hydride, etc.) began to persist. Therefore, this statement can be said to be misinformation at first. After a sample survey, it can be seen that quite a few people are confused about the charging methods of the two batteries.

The charging and discharging characteristics of lithium batteries and nickel batteries are very different. All official technical data carefully reviewed emphasize that overcharging and overdischarging can cause great damage to lithium batteries, especially liquid lithium-ion batteries. Therefore, it is best to use standard charging time and standard methods, especially long-term charging of more than 12 hours. Usually, the charging method described in the mobile phone manual is the standard charging method suitable for the mobile phone.

(2) If the battery is not charged for a long time, charge it again after the battery is completely cut off.

After the battery is fully charged, the mobile phone or lithium battery charger will automatically stop charging. There is no "trickle" charging for more than 10 hours as stated by the nickel charger. After the lithium battery is fully charged, it will not charge when placed on the charger.

Excessive charging and full use of discharge will cause overcharge and overdischarge, causing permanent damage to the positive and negative electrodes of the lithium-ion battery. At the molecular level, overdischarge is the excessive release of lithium ions from the negative electrode carbon, and its slice structure collapses. Overcharging forces excess lithium ions to block the carbon structure of the negative electrode.

(3), battery life

An experimental table about the charge and discharge cycle of lithium-ion batteries, and the data on cycle life are as follows (DOD is the abbreviation of depth of discharge).

Cycle life (10%DOD):gt; 1000 times

Cycle life (100% DOD):> 200 times

According to the above data, the number of recharges is related to the depth of discharge. The cycle life of DOD at 10% is much longer than that of DOD at 100%. Of course, if converted into 10% of the actual charging relative total capacity, 1000=100, 100% 200=200 , then the latter full charge and discharge is preferred. However, the life of a lithium battery is mainly reflected in the charge and discharge cycle, which is an absolute concept. The last time it used 30 percent of the power, it was fully charged, and the next time it used 70 percent It is fully charged when the power is supplied, which happens to be a charging cycle. Therefore, it is better to use lithium batteries in accordance with the slogan of the inventor of lithium batteries: "charge as soon as you use it, charge and use as soon as you use it".

(4), regular deep charge and discharge for battery calibration

Lithium-ion batteries usually have a management chip and a charge control chip. The management chip has a series of registers that store values ​​such as capacity, temperature, ID, charging status, and number of discharges. These values ​​will gradually change during use. Instructions for Use The main function of the "should be fully charged in about a month" method is to correct inappropriate values ​​of these registers.

The charging method of 2,3V lithium battery is voltage-limited cross-current method

It is mainly completed in 3 steps:

Step 1: Determine the voltage <3v, precharge="" first,="" 0.05c="">

Step 2: 3 v <4.2v, determine="" constant="" current="" charging="" 0.2="" c1="" c="">

Step 3: Voltage>4.2v, constant voltage charging, the voltage is 4.20v, the current decreases as the voltage increases, and it is judged to be fully charged.

In fact, I didn't know anything about this today, so I looked it up online and understood it as common sense.

When charging starts, first detect the voltage of the rechargeable battery. If the voltage is below 3V, precharge is performed. The charging current is 1\/10 of the set current, usually about 0.05C. After the voltage rises to 3V, the standard charging process is entered. .The standard charging process is constant current charging with a set current. When the battery voltage rises to 4.20 V, it changes to constant voltage charging to keep the charging voltage at 4.20 v. At this time, the charging current gradually decreases. If it decreases to 1\/10 of the set charging current, the charging ends.

Usually, the charging current of lithium batteries is set between 0.2C and 1C. The larger the current, the faster the charging, and the battery will also heat up.