Digital battery

According to the report of the research firm market lithium-ion rechargeable battery shipments worldwide have continued to increase in 2007 lithium-ion rechargeable battery compared to world supply in 2006 increased by 17% because lithium-ion batteries in energy density advantage of using lithium-ion batteries can reduce system complexity and cost of system integration.

 

Lithium-ion rechargeable battery characteristics with the load / discharge the requirements of

Lithium-ion rechargeable battery with a single high voltage, small size, light weight, energy density, long cycle life, self-discharge current is small, no memory effect and no environmental pollution, good prices and benefits of weight. And the lithium-ion battery curve of discharge is very flat, so you can drain the battery within a period of stability in the whole power is ideal for small portable power power.

 

Series of lithium-ion battery voltage is usually 3.0 ~ 4.2V. When the battery is discharged, the voltage is subsequently begun to decline, the output voltage can change dynamically with the load changing. Table 1 shows the lithium-ion batteries on other features.

 

Lithium battery ion / lithium-ion batteries discharge need to monitor the voltage on the one hand to avoid overloading the other hand, to prevent excessive discharge. Would charge lithium-ion battery / control discharge testing of Dell Inspiron 1526 battery capacity and charge / discharge anomalies occur in the process to ensure protection.

 

When a number of series lithium-battery ions / use of landfill series after differences in the characteristics of lithium-ion batteries large lithium-ion battery, there was the specific charge or increase the probability an excessive discharge. Therefore, discharge of lithium-ion battery, the need to use a special discharge circuit when a battery voltage of lithium-ion battery discharge drops, until the following limit can automatically cut the discharge circuit , does not discharge lithium-ion battery appears to decrease their useful life. In addition, lithium-ion battery when charging lithium-ion battery should pay attention to time and changes in lithium battery temperature ion, so it will not be accountable for ensuring that battery life of lithium-ion battery. If the battery is over-load, it will accelerate the aging, but also the loss of energy it can transmit the system. Therefore, multi-cell lithium-battery ion / discharge circuit to take into account more problems than single-cell lithium battery ion / discharge circuit to consider the issues more.

 

Stored for a long period has been discharged lithium-ion batteries may be in a state of deep discharge (each set of lithium-battery voltage ion is generally less than 3V). In this case, for a full lithium-ion Dell Inspiron 5100 battery charging process to be completed some time before the trickle charge.

 

A larger load current can not make time for lithium-ion battery charge too. A voltage greater load current can be rapidly achieved peak, but the float take some time. Typically, the float is twice the initial charging time.

 

Rechargeable lithium-ion battery with the first constant charging current, then a constant voltage means, first of 1C or less constant load current until the battery voltage reaches the voltage limit load. Value of constant voltage is generally between 4.1 ~ 4.2V, precision constant voltage to be controlled to ± 1% or less, depending on the lithium-ion battery manufacturers, and lithium-material ion battery anode.

 

A typical lithium-ion battery charging characteristic curve in Figure 1. In the constant voltage phase, lithium battery ion current decreases. The voltage reaches the threshold voltage and load current to 0.03C (nearly 3% CI), the charging process is usually at the end. Most lithium-ion Dell Inspiron 5150 battery charger full power for about 3 hours. As lithium-ion batteries self-discharge rate is relatively low, so generally no need to run the current process of pricing.

 

Rechargeable lithium-ion battery to provide voltage regulation to correct a problem in addition to the two ends of the battery charging voltage is not exactly equivalent to be added to each battery voltage section. Unlike the battery in the various components of the voltage drop I × R caused. These factors include termination resistors in May, the protection of MOSFET on resistance, internal connections and detect resistance (for example, used to measure the capacitance of the battery).

 

Solution to this problem is in the lithium-ion battery voltage constant phase compensation of dynamic tension. “Dynamic” refers to the charge that I run, diminishes the value of compensation I × R, but also with the decrease. For example, TI bq2057 Charge Management IC has the function of automatic compensation.

There are three main methods currently used to determine the state of battery charge: measuring voltage, resistance power calculation and measurement.

 

The method of computing power is more complicated. The measure of power to be able to constantly monitor the Dell Inspiron 6000 battery voltage, current and temperature. Then, as the discharge rate, aging and temperature to adjust capacity, and was followed by a state of battery discharge, the remaining power, the battery can also use the time.

 

The main source of errors in power calculation due to cellular aging, self-discharge, and product differentiation between manufacturers, resulting in changes of the impedance of the battery. In addition, power calculations to measure the electricity consumption would only power the full power to run completely out of time to update the discharge capacity of the battery, and users do not often the battery has been fully developed electric shock.

 

Power measurement method using the impedance voltage based approach to determine the onset of the condition of battery and lack of capacity. Then they charge in a case of using a long-term approach by adjusting the remaining capacity of the battery and the beginning of the state. They are in every cycle depending on the voltage and current information updated calculation of the impedance of the Dell Inspiron 6400 battery. Finally, based on open circuit voltage and impedance information, calculate the average load in the remaining time available for a discharge curve.

 

IT in the “Impedance Track” The technology is based on the introduction of chip barometer bq20z80. A claimed that the use of the battery throughout the process, the accuracy of calculating the power of lithium battery is left at 99%. The chip barometer with an SMBus interface to the battery capacity of the information transmitted to host controller system. Host Controller remaining power management battery to extend the use of the system time.

 

Smart Battery

Present Dell Inspiron 700m battery rechargeable / discharge management, extensive use of a variety of practices and MCU / CPU for data exchange, processing a variety of bus technologies, for example, few buses (BITBUS ), System Management Bus (SMBus), IC exchange of data between bus (I2C), Universal Serial Bus (USB) and a simple peripheral bus (SPI) and so on.

 

In laptops, the use of bus technology may be state of the battery, the battery can be used time and energy remaining battery, batteries, parameters such as the battery if it is normal for the management and inspection, and make the battery status data shows that when the battery is exhausted, the computer may turn off automatically to save the data. Similarly, in the current widely used mobile phone these technologies have also been widely used, greatly facilitate the users use.

 

Someone under the smart battery is defined as follows: drums + electronics + control bus = Smart Battery. Smart Battery, SMBus, and “smart Dell Inspiron 8500 battery charger, the three formed a Smart Battery System (SBS).

 

The multi-cell lithium-ion battery charge / control of protection against discharge IC

Lithium-ion rechargeable batteries due to a series of advantages and it has become increasingly broad range of applications in the world large companies integrated circuit fabrication (such as Ti, Maxim, Linear, National, and Intersil Corporation, etc.) have launched a number of models of multi-cell lithium-ion rechargeable battery management integrated circuits. These products with different features, excellent performance, each section can be responsible for lithium-ion battery / discharge conditions and charge / discharge temperature detection and protection. Among them, some use 8-bit MCU core and the charge of lithium-ion battery / unload work of the state register of lithium battery ion / discharge the work of the host state and analyze and judge, to ensure that each lithium-ion battery is fully charged, and extend its life.

 

TI introduces bq2150H lithium-battery ion / discharge detection and protection control IC, which can be used for 2 to 5 series Li-battery ion / discharge applications, can be used alone, and may take five load / unload work LED display.

 

TI introduced the UCC3957 is used for 3 / 4 charge Li-ion Dell Inspiron 8600 battery / cons discharge protection of integrated circuits, through the state’s internal mechanism can be achieved for each section of the battery over charge / discharge detect and protect lithium-ion battery over-discharge protection current. UCC3957 by external P-channel MOSFET control of the load carrying / protection against discharge, using two charge / discharge over-current protection functions of command. If the charge / discharge process of lithium-ion battery is not connected, the screening can be achieved through the control of appropriate protective UCC3957.

 

TI has introduced the series bq2941X lithium-ion battery charge control IC is used to protect 2/3/4 two lithium-order ion battery protection for a series of integrated circuits, the main characteristics is that they charge Surge Protection against voltage threshold is different Equipped with high precision on-detection circuit voltage and the on-time voltage detection circuit programmable delay. Pulse work load.

 

Linear Introduces Lithium-Ion Battery Charger IC control such as LTC4006/LTC4007/LTC4100, etc., for 2 ~ 4 Li-Ion Dell Inspiron 9200 battery charging, while the LTC4008 can be used for 2 to 6 Lithium-ion battery charging applications , the maximum load current is 4A, the maximum input voltage 28V, using switching control workload.

 

National Semiconductor has introduced the LM3420 series of lithium-command Ion battery charge IC can be used for 1 ~ 4 Li-battery charge control to ion charge Li-ion battery control, linear and switching applications circuit.

 

MAX1894/MAX1924 Maxim’s, etc. 3 / 4 Li-Ion battery charger IC can be obtained with the control of each cell lithium-battery ion / discharge voltage detection to prevent lithium-ion battery over load / under charging, effectively extends the lithium-ion battery life. With due to charge / discharge the battery and short circuit box caused by the charge / discharge is not normal protection and trickle charge current control can be used to control the release of deep charge battery safety Automatic. MAX1894X for four sets of rechargeable lithium-ion battery applications, protect the threshold hysteresis, while MAX1924V and / MAX1924X can be used for 3 / 4 series Li-ion Dell Inspiron 9300 battery charger at the threshold of protection has hysteresis. MAX1894/MAX1924 have two logic-input signal level, the use of these two logic input signal level by the MCU to complete the process of lithium-controls shutdown of ion battery.

 

Maxim has introduced the MAX1870 is another circuit smart battery management integrated charge that can be Use 2 to 4 Li-control applications of ion battery charge, the integrated user-programmable 8-bit RISC-based micro - controller, data multi-channel Get channel cell, high-speed SPI interface circuit, master / slave SMBus interface circuit that allows the detection of lithium-ion battery. The use of multiple MAX1870 is string data acquisition circuit unit can be detected in the accuracy of 50mV in voltage lithium-ion battery, and using multiple channel data acquisition unit circuit of the MAX1870 to detect temperature inside and outside, easy to use.

 

Another example Intersil has introduced the ISL6251 ~ ISL6257, ISL6258 and ISL88731 (using SMBus) and other lithium-ion battery management ICs load control can be used for 2 to 4 Li-management applications Ion battery.

 

Intersil has introduced the ISL9208 can be used for a maximum of seven lithium-load management ion Dell Inspiron 9400 battery and control circuit with a load inside and outside the functions of detecting temperature protection control. In the ISL9208 has an internal embedded MCU cores, using the MCU core can complete the charging of lithium-order ion battery management. 4 ~ 7 series rechargeable lithium-battery voltage ion charge up to 30V through the MCU core, detection and control can be obtained for each cell lithium-battery ion / discharge detection power and control, ensuring the charge / discharge lithium-ion battery voltage balance and the battery life of lithium-ion battery. And the ISL9208 supports a multi-cell lithium-ion battery charging applications in parallel, the use of flexible and practical.

 

Summary

Use lithium-ion battery is growing, while lithium ion Laptop battery charge / discharge management has also become a very important and reasonable to charge lithium-ion battery / discharge of lithium-life ion battery and the use of safety are of great importance. And multi-cell lithium-battery ion / discharge and there is a continuous flat load / discharge, adequate electricity and not to discharge problem, to solve these problems, is inseparable from lithium-charge of ion battery management / discharge, because the rich control IC function, using lithium-IC battery ion / management of discharge is a good solution.