digital batteries

In practice, due to the difference between two lithium batteries monomers, after a period of loading and unloading of the battery and found the only upper and lower voltage appears uneven phenomenon seriously affect system performance. In response to this situation raises the equilibrium and under the concept of equilibrium, then the lithium Laptop battery, the next in-depth study of a balanced circuit. Experimental results show that lithium batteries several correctness of circuit design balanced system design of high performance hybrid has laid a solid foundation.

Devices for energy storage for dynamic current of the battery are: the lead-acid batteries, nickel-hydride batteries, metal and lithium-ion batteries.

Span of lead acid batteries contain toxic substances like lead, and high energy density is low, charge and discharge and short life, the refractory waste and other shortcomings, has been largely eliminated by future systems energy storage [1].

Ni-MH batteries are alkaline batteries, due to tension monomer is relatively low, and there is “memory effect” on a regular basis the large-scale dumping is necessary, which greatly increased the tasks of system power management . Secondly, its also self-discharge rate (10% ~ 15%) of defects [2-3].

In comparison with other batteries, lithium-ion IBM ThinkPad T40 battery with high power density (800W/Kg), single high-voltage (average voltage of 3.6 V), does not pollute the environment, self-rate discharge is low (about 3% ~ 5%), there is no “memory effect” and other characteristics, is an ideal battery power [4], it has been widely used in mobile power , hybrid cars, the switchgear and low voltage devices in standby power, such as space flight, the device energy storage.

An internal force of the lithium-circuit fault protection

Monomer average voltage of lithium battery is only 3.6 V, the discharge current also certain requirements. To improve the current system and level of tension, in some occasions, generally use parallel dynamic series after the formation of high-current, high voltage Li-ion battery as the energy systems. As the voltage is very sensitive to lithium batteries, batteries are generally increased when using a certain protection circuit. View the most dynamic of the internal circuitry of lithium battery protection was found, its protection circuit is fairly simple, usually only over / under voltage / over current / short circuit protection. In normal use, this hp F4486B battery can be normal in a short time of loading and unloading. However, the inclusion of the protection circuit with lithium batteries used in systems for hybrid electric vehicles are going through a phase of high current discharge and charge, we found the maximum voltage between monomers and lower voltages serious inconsistency: Yes monomer other batteries in charging the battery voltage is always under normal conditions, because its threshold voltage has reached the maximum protection of recharge channels are closed, resulting in the total pressure on the entire energy system can not pre-determined requirements, another set of monomer battery voltage is still within the normal discharge conditions, because of its voltage reaches the lower threshold voltage is closed to protect discharge channel, causing the entire energy system can not be fully discharged. These two phenomena have seriously affected the performance of energy systems for monitoring the equalization of the toshiba PA3383U-1BRS battery is to solve the above-mentioned phenomenon of the most effective approach.

2 Improved Lithium Battery Protection Circuit Principle

A balanced circuit is the first man to reach the hardware circuit, which may limit the battery voltage of the monomer or monomer between the coherence between the minimum voltage to effectively protect the battery charge voltage and lower the ceiling voltage discharge , from a fundamental to reduce the impact of the battery on the system to improve battery performance and extended to battery life. It includes the balance and balance of both types of circuit to its name suggests, they were the maximum protection of the battery voltage and the voltage limit of the battery.

In this paper, two sets of vehicle design hybrid electric power system: Series 3 Li-ion battery system protection (maximum voltage of 12.75V, the average discharge voltage of 10.8 V) and channel 10 system lithium apple M8403 battery protection (maximum voltage of 42.5V, the average discharge voltage 36V), discharge current, 10A and 40A respectively. System principle illustrated in Figure 1, which is in its protective circuit basis (over / under voltage / temperature / over current / short circuit protection) based joins the upper and lower balance circuit.

2.1 EQ TL431

TL431 is a three-terminal shunt tube regulator, its basic features can be found in reference [5] This article, based on the characteristics of their designs on the balance of the circuit shown in Figure 2. Adjust R1, R2, R3 resistance when the voltage exceeds a set value when they opened TL431, through the resistor R * Power consumption of energy to reduce battery voltage to reach a fixed point (equilibrium point). With the internal electric vehicles and electric vehicles equipped with a balanced circuit experimental results when the balance to be 4.20V, the resistance values are: R1 = 68kΩ, R2 = 100kΩ, R3 = 4.3kΩ.

The balance of the next circuit based on TL431 as shown in Figure 3. When the switch is off, because of optocoupler 817 is not opened before the class to optocoupler circuit also unable to work after school, the work of the BATCL50L battery in a state of normal discharge; When closed, the Post optocoupler optocoupler stage with the opening of the first class one after another opened, the circuit through the resistor R18 to reduce energy consumption and protect the chips sent until the voltage battery is low to protect the chip to force the battery voltage is stable at its low voltage limit Vmin, to achieve the objective and balanced.

From this principle of a balanced circuit can be seen that the current balance of the circuit can not exceed the upper limit of protection TL431 current (70mA or so). Capacity constraints due to a balanced, high-current charge and discharge can be applied between the circuit. To increase the balance of the circuit without compromising the ability of TL431, the TL431 can be used in parallel.

2.2 Parallel equalizer TL431

TL431 shunt and balanced the circuit shown in Figure 4. The principle is similar to Figure 3, only through parallel TL431 for the balanced expansion of current targets. Found in the actual production, as TL431 has a small difference between doing two average balance of power is not entirely consistent. To reduce the occurrence of these phenomena, the general screening methods to improve the TL431 for these circuits, which probably increased the workload of production.

2.3 Improving the equalizer TL431

To improve the balance of the capacity of the circuit, while reducing the workload of the TL431 output filter, this article using the 8550 design of an improved balance of the circuit of power transistor as shown in Figure 5. Once the extra power when TL431 will open, 8550 launch of a PN junction due to handle pressure and opening resistors consumes IBM ThinkPad T41 battery power until the battery voltage on the equilibrium point. Once balanced, the figure would be light-emitting light-emitting diode has played the role of operational instructions. By adjusting the set R1, R2, R3 resistance, they can set the balance point of the upper spring. Figure R1, R2, R3 resistance is relatively large, after the close of the TL431 little effect on the equilibrium point can be ignored. And the balanced circuit is also shown in Figure 5, only a change of R1, R2, R3 corresponding resistance.

3 Experimental results

The compositions of these functions with a string of 10 Office of Protection of lithium batteries a 400W DC motor driven experiments and found that all protective plates in a lithium battery when the total pressure of about 42.5V charging off tube protection against surges on the ground, pressure or almost total 29.2V for the discharge out of the market when the protection of the tube voltage, protecting the plate with a battery pack lithium in the testing stage for overcurrent detected: discharge current of 39A or more, the protective panels were made over-current protection, temperature of 109 ° C when the switch in the off-discharge circuit, the effective protection of the market of the discharge tube. The above data indicate that the circuit is essentially achieved the over / under voltage / over current / over-temperature protection, the basic requirements.

After a long round-trip charge-discharge test, collect relevant data, drawings, can be achieved without a balanced circuit waveforms comparing the experimental data are: the balance of the circuit of a hp PP2182D battery lithium and lithium 2 upper limit of the variation in battery voltage, such as that shown in Figure 6 and Figure 7, the ultimate balance of protection of lithium batteries 3 times the upper limit of battery voltage changes as shown in Figure 8, and balanced with the protection of batteries and lithium batteries 4 of 5 threshold voltage to change the battery of Figure 9 and Figure 10 shows the non-balanced circuit with 6 cells Lithium minimum voltage of the battery as shown in Figure 11. Figure 1, the points of all curves measured for the first time the limit of the battery (bottom) voltage, curve 2 points for long term running of the toshiba PA3395U-1BRS battery measured upper limit (lower) the voltage value.

On the accession of a balanced circuit the maximum voltage of the battery is maintained at an equilibrium point of 4.22V and 4.18V or more, effective protection of the upper limit of the battery voltage, non circuit to balance the maximum voltage of the battery which seems random, by virtue of membership of a balanced circuit the battery voltage level is maintained below the equilibrium point around 2.91V, the effective protection of the lower end of the battery voltage, non-balanced circuit limits the voltage of the battery which seems chaotic, badly damaging the battery life of the nature of coherence and the.

This departure from the practice of engineering, the dynamic nature of lithium batteries in a phase of high flow discharge occurred after the upper and lower limits of the phenomenon of unequal tension is proposed based on the balance of the circuit TL431, and lithium-depth study of a balanced circuit. Practical results show that the design and balanced on the balance circuit and the circuit not only ensures high speed of discharge of the battery after the battery requirements of consistency, but also effectively protect the battery voltage the upper and lower limits for the further study of high battery performance energy storage systems and hybrid systems for electric vehicles has laid a solid foundation.

Currently on the market used mainly in nickel-metal hydride secondary battery (Ni-MH) and lithium-ion (Li-ion) types. Lithium-ion batteries have been mass production of liquid lithium-ion battery (LIB) and lithium-ion polymer battery (LIP) of two kinds. Therefore, in many cases, the battery mark on the Li-ion Laptop battery should be lithium-ion battery. But not necessarily that of liquid lithium-ion battery, also possible that the polymer lithium-ion battery.

Lithium-Ion battery is a lithium improved products. Lithium batteries have a long time ago, but lithium is very active (remember its location in the periodic table do?) In metal, it is not very safe when used often in charge when burning, burst position, then there is an improved lithium-ion batteries, lithium can inhibit the added element of active ingredients (such as cobalt, manganese, etc.) so that lithium achieve truly safe, effective, practical , while lithium batteries will also former largely eliminated. As for how to distinguish them from the label of the battery will be able to identify, lithium battery for Li, Lithium-ion IBM ThinkPad T40 battery for Li-ion batteries. Now, laptops and cell phones using the so-called “lithium batteries”, in fact, are lithium-ion battery.

The basic structure of modern batteries, including tubes, anode and electrolyte of three elements. As a kind of lithium-ion battery also has these three elements. General-technology lithium-ion battery uses a liquid electrolyte or gel inorganic shell requiring a solid fuel to accommodate the active ingredient, which increases the battery weight and cost, but also limits the size and flexibility of styling. In general, liquid lithium-ion secondary battery is a minimum thickness of 6mm, a further reduction on the most difficult.

Lithium is known as polymer-ion batteries are the three main structures in at least one or more of the use of polymer materials as its main battery system.

A new generation of polymer lithium-ion polymer Dell Inspiron B120 battery technology is already very high, if the form can be thin (thinner than 0.5 mm), any size and any form of greatly increased battery Design Flexible, it may therefore respond to the request, made any shape and capacity of the battery. At the same time, polymer lithium-ion battery pack energy than current lithium-ion batteries in general has increased 50% capacity load discharge characteristics, safety, the operating range of temperature, cycle life and environmental performance in such aspects as compared to lithium-ion battery large rate increase.

Currently marketed in liquid lithium-ion battery (LIB) where over-charging the battery, and therefore likely to cause safety valve ruptured fire situation, it is very dangerous, if the need to protect the IC circuit installed to s’ ensure that the battery is not on – in charge of the case. The lithium ion polymer battery, this type of lithium battery-ion batteries in terms of liquid relative has good resistance to load and unload features, adding requirements external circuit protection IC may be suitably relaxed. In addition, in the charge, the polymer lithium-ion batteries can take advantage of the IC load current constant, and lithium-ion secondary sony VGP-BPS5 battery used in CCCV Currert (Constant-voltage constant) load means the time required for comparison can shorten a lot of time waiting.

Although the advantages of lithium-ion battery package, but there are gaps, such as charge and discharge times of high prices and less. Lithium loading and unloading of the number of times 400-600, specially modified products, but many times 800. Nickel-metal hydride rechargeable batteries for more than 700 times to obtain a certain quality and a good product charge and discharge up to 1200 times, so a comparison, the nickel-metal hydride battery live longer than lithium batteries. In addition, the price of nickel-hydride batteries in metal is also much lower than lithium batteries. Moreover, strictly speaking, lithium batteries have the same memory effect, except that it is indeed very little memory, it is essentially negligible.

Thus, there is no perfect battery.

With the popularity of high frequency switching power supply, valve lead acid batteries have been widely used in the power system. Because of its completely sealed, no need to add water to maintain previously known as “maintenance free” battery. That maintenance “free” is a misleading term, which allows the user to relax on the valve regulated lead daily maintenance of battery acid and management, which reduces Laptop battery capacity and lesions early due to lack of battery capacity, or failure in substations and power generation plant accidents were frequent. Therefore, the proper use and care dimensional lead-acid battery VRLA battery to increase their service life is of great importance.

Affecting a major valve battery life

The normal life valve lead acid batteries for over 10 years, in theory, may be 20 years but in actual use often insufficient capacity, failure or early phenomenon. Affect the life of valve lead acid batteries of many factors, including:

1, the ambient temperature

The battery at 25 ℃ environment, availability of a longer life. Temperature, the battery will exacerbate corrosion of the plates at the same time will consume more water, thus reducing battery life, long term operating temperature if higher than 10 ℃, life is about halfway. Valve lead-acid IBM ThinkPad R51 battery changes in capacity with changes in temperature, 25 ℃ when the battery has a capacity of 100% at above 25 ℃, 10 ℃ for each increase in battery capacity would be halved .

Must be careful to do according to actual temperature changes to streamline construction lead-discharge battery acid present, while a battery compartment of the right to control the temperature kept at 22 ℃ ~ 25 ℃ or less.

2 overload

The long-term overload state, the cathode due to the reaction of oxygen evolution, the water is consumed, H + increase, which increases the acidity and near the cathode, the grid corrosion accelerated, causing thinning of the accelerated corrosion of the grid battery, battery capacity reduced, the same time due to water loss intensified, would have drained the danger of the Dell Inspiron 1501 battery, affecting the battery life.

3, an excessive discharge of

Excessive battery discharge occurred mainly in the AC power outage, the battery time to load. When the battery runs down its on-voltage is too low or zero, this will lead to a large number of sulfuric acid inside the battery lead is adsorbed on the surface of the cathode of battery, resulting in the cathode Battery “sulfate.” Lead sulphate is an insulator, its formation is related to the battery charge and discharge performance, have a tremendous negative impact, and therefore the formation of sulphate in the cathode, the higher the greater the internal resistance of batteries, the battery charge and discharge performance, the worse the shorter the lifespan of the battery.

4, the conditions of low discharge current, the impact of

In the discharge current small formed under the particle size of lead sulfate as the conditions of the large discharge current, the size requirements of mainstream higher than the rate of formation of crystals smaller than current conditions, slow the growth of crystals too late to be oxidized very rapidly reduced, and thus a relatively smaller size, whereas in conditions of low current, a crystal of lead sulfate great can be easily restored. Such that crystals of lead sulfate is not a long-term cleanup, will certainly affect the hp 338794-001 battery capacity and longevity. Therefore, the actual expense of the current battery capacity must be executed under a precise calculation.

5, the unbalanced nature of the impact of charge-discharge

The study results showed: composition of the grid alloy and structure in different parts of the distribution is different, leading to the unbalanced nature of the electrochemical properties grid [2], the imbalance is to turn in the float and the load condition of discharge voltage are different, and will be in charge and discharge cycle, so that this difference is increasing and training the so-called “rear battery (battery failure).” The current domestic standards in a group of toshiba PA3191U-2BRS battery float voltage difference between the largest to be ≤ 50mV, the norm in developed countries are ≤ 20mV, should pay attention to the battery and reduce floating state operating voltage differences.

6, thermal runaway phenomenon

As the use of depleted fluid valve regulated lead acid battery design, the infusion of battery electrolyte are adsorbed on the fiber glass, when the load current increases, it is necessary to leave the gas valve, which causes the loss of farm water resistance by significant volume reduction of the charge and discharge large amounts of heat generated in the process, which propagate the heat that the temperature has been taken too late, they will form a thermal runaway. Thermal runaway causes are not promptly reduced float voltage, lax safety valve or pressure valve is open too low, etc. In severe cases of thermal runaway if the landfill has the potential DIP apple A1008 battery voltage transient and Sustainable Housing battery temperature rose to 70 ℃ ~ 80 ℃, and therefore thermal runaway must be a high level of attention.

7, long-term impact of floating charge

Float charging status of battery in the long term, pricing and not the discharge is required to cause passivation of the anode of the battery flat, so that the battery internal resistance increases, the capacity is severely reduced, resulting a shortened life of the battery.

Second, improve the life of valve lead acid battery of measures

With this purpose the life valve lead-acid batteries of factor analysis to improve the life of valve lead acid batteries, we must do:

1 battery of stringent quality levels. In selecting the battery and the process of procurement, we must fully understand the production process manufacturer, manufacturing process and quality control, as well as specifications and so on, if necessary, require manufacturers to conduct the first in the capacity of experiments to screen a difference smaller IBM ThinkPad T40 battery.

A reasonable choice charger. Since the food was monitored over real time and intelligent management capabilities, allowing the battery sealed in the best condition always work, so use high quality switching power supply as a charging unit. High frequency switching power supply system, adopting modular design, when a module is a failure, should be able to immediately withdraw from the race does not affect the normal operation of other modules, module parts should be able AutoFill that batteries are not due to failures caused by excessive discharge module.