CN102856942A - Charge-discharge omni-directional equalization managing device of lithium ion battery pack - Google Patents

Abstract

The invention provides a charge-discharge equalized and charging system integrated digital battery management system of a lithium ion battery pack, relates to a charge-discharge distributed type digital dynamic management device of a lithium ion power and energy storage battery pack with multiple units connected in series for using and aims at solving technical problems of existing battery management systems to break through technologies of charge-discharge stored energy equalization and resistance equalization, technologies of application of high-power switching power supplies to lithium ion battery packs and technologies of integration of battery management systems and independent charging systems. According to the device, charging and discharging bidirectional synchronous energy of each battery unit in the lithium ion battery pack are directly transferred and discharged in an equalization mode, and the purpose that the energy is transferred and discharged in an equalization mode during equalized charging and discharging of large current of each battery unit in the lithium ion battery pack is achieved; and the device integrates an independent external battery charger system with a battery unit management module so that the charging system is light and miniaturized.

Description

The lithium ion battery group discharges and recharges comprehensive balance management device

Affiliated technical field

The charge and discharge that the present invention relates to lithium ion power that the series connection of a kind of multiple unit uses and energy-storage battery group are distributed, dynamic battery management system and the management method of digitlization and system integration.

Background technology

Along with to country to new forms of energy and new-energy automobile, particularly electric automobile is encouraged the in succession appearance of support policy, the application of chargeable lithium ion energy storage and power battery pack is more and more extensive, as a kind of novel chemical power source, lithium ion battery has that light weight, volume are little, memory-less effect, have extended cycle life, the advantage such as safe, pollution-free, adaptive temperature is wide, be the NI-G that substitutes present mainstream applications, optimal electrokinetic cell and the energy-storage battery of Ni-MH battery.

But, because present domestic lithium ion battery material performance and batch unstable properties, battery production technology is from mixed oar, film, roll-in, the section film-making, assembling, welding, fluid injection, change into and the humidity of partial volume in the finished product process, temperature, viscosity, machining accuracy is perfect not to the utmost with control technique, even through strict trace routine, the voltage of each battery unit, resistance, capacity is also basically identical, but forming several strings, tens strings even the battery pack more than the string up to a hundred are after a period of time recycles, because its particular electrical chemical characteristic, the internal resistance of battery, voltage, the parameters such as capacity also can produce fluctuation, form inconsistent state, cause the difference between the battery unit.This species diversity body surface now be full of for battery pack or the series-connected cell core when discharging between voltage not identical with capacity.This situation has directly caused the battery of battery pack overtension in the process of charging to trigger ahead of time the battery pack overcharge protection; And the battery of brownout can cause the battery pack in discharge process, thereby the whole volume of battery pack is obviously descended.The actual capacity for the poorest battery of battery pack performance of the capacity that whole battery pack embodies, thus further aggravation overcharges and crosses the appearance of putting phenomenon, buries potential safety hazard, reduces the whole cycle life of battery pack, causes it to lose efficacy in advance.Therefore, the circuit of the difference requirements operation between the unit of lithium ion battery group can be finished the equalization operation to battery unit, accurately manages the charging and discharging of lithium ion battery group.

One, the lithium ion battery group discharges and recharges key technology---balancing technique

The balance charge/discharge technology mainly is in order to solve the bias phenomenon of the electrochemical properties of unit in long-term charge and discharge cycles process in the lithium ion battery group.Lithium ion battery substitutes cadmium nickel, Ni-H cell can not be applied mechanically traditional simple " plug and play " mode.This is that namely lithium ion battery must be forbidden to overcharge and overdischarge because lithium ion battery and cadmium nickel, Ni-H cell have the difference of a maximum.Therefore, must be in conjunction with lithium ion battery characteristics design new management of charging and discharging circuit structure and control and management technology.

In through engineering approaches was used, the battery unit that the battery cell of lithium ion battery composes in parallel must be connected into battery pack, therefore must consider the balance phenomenon of each battery unit in the charging process or battery cell module.As time goes on, this balance phenomenon can be further serious, affects battery life and reliability.Therefore, equalizing charge and discharge are the key core technology that lithium ion discharges and recharges, i.e. overall process, dynamic and intelligent equalization technique in the charge and discharge process.

So-called lithium ion battery group equalizing charge and discharge are exactly that the voltage deviation between lithium ionic cell unit is remained in the default scope, thereby guarantee that each battery unit carries out equalizing charge and control of discharge in the process of recycling; And along with the increase of charge and discharge cycles, alleviate or reduce the voltage differentiation between each battery unit.

Two, existing battery set charge/discharge is balanced

Equalization methods commonly used has energy storage equilibrium and resistance equilibrium at present.

The energy storage equilibrium is to utilize battery to the charging/discharging function of the energy-storage travelling wave tubes such as inductance or electric capacity, realizes the switching of energy-storage travelling wave tube between unbalanced battery unit by relay or switching device, and the energy that reaches between battery shifts.The general more complicated of this balanced charging method control network is had relatively high expectations to security management, notes also in use the time that discharges and recharges of grasping energy-storage travelling wave tube.Its maximum advantage is during charge and discharge (work) are used, but functions of each element cell of balance all, and do not consume the electric energy of lithium ion battery group.

The resistance equilibrium generally is by the break-make of controller controlling resistance network battery pack to be carried out loading sharing, balanced principle is in the process of batteries charging, when certain batteries charging rate very fast, voltage is higher than other batteries, system reduces the charging rate of battery, to reach the purpose of each batteries equalizing charge by the conducting shunting of control switch control equalizing resistance, this method can be carried out equilibrium to multiple batteries simultaneously, and control is simple.If but resistance choosing excessive in the balancing procedure, then euqalizing current is too little, has little effect; If the resistance choosing is too small, then resistor power is very large, and the system capacity loss is large, and balanced efficient is low, and system's opposite heat tube reason is had relatively high expectations, and need to carry out temperature detection control.

Three, existing lithium-ion battery pack managing system is in the drawback of control circuit and balancing technique

1, battery pack detects

The battery management system major function of having gone on the market at present, is to detect the data targets such as the total voltage of the voltage of battery unit, battery pack, total current.But; the basic principle of its design is that battery pack according to multiple unit series connection is as a unique unit; occur overcharging in the unit or after to one's heart's content condition alarm and (or reduction) current direct to cutting off total anodal and total negative pole, to realize the simple logical circuit protection of battery pack.

Because this series products does not possess the charge and discharge balancing management to distributed unit, whole charging and discharging is close to " naked filling or naked putting ", can't make the high efficiency charge or discharge of normal battery unit, lasting circulation is gone down and can directly be reduced overall operation ability and the cycle life of battery, so, from the technological layer definition, belong to elementary battery pack detection device.

2, the terminal balanced battery management system of unidirectional charging

The maximum characteristics of this series products are the control templates that is provided with the battery module that some battery units form, and when setting index, stop the charging of this module in the voltage that detects this module or predefined control index, avoid overcharging.This pattern belongs to terminal charge balancing, does not possess the equalization discharge function, and the control template volume under this pattern is large, weight is large, also needs to carry out information exchange with charging system independently and communicates by letter, can't integrated two systems.Being because of the similar bypass circuit technical approach of this control module with drawback in addition of this pattern can't be avoided the charge balancing electric current that the battery assembly module series connection causes excessively low, and actual effect is not good, can't really play the function of charge balancing.

Summary of the invention

Main purpose of the present invention is exactly in order to solve existing battery management system technology drawback, breakthrough discharges and recharges energy storage equilibrium and resistance balancing technique, high power switching power supply is at the application technology of lithium ion battery group and the integrated technology of battery management system and free-standing charging system, a kind of lithium ion battery Battery pack distributed unit is provided, the digitlization battery management system of charge and discharge balancing and integrated charge system (is called for short: distributed lithium-ion battery pack managing system/Distributive Digital Equalizer of Li-ion Battery Packs, DDE-BMS).This invention relates to that the charge and discharge of lithium ion power that the series connection of a kind of multiple unit uses and energy-storage battery group are distributed, the digitlization dynamic management device.The charging and discharging bi-directional synchronization energy that this device has not only solved each battery unit in the lithium ion battery group directly shifts equilibrium, realized that euqalizing current is the same with charging current large, reached the balancing energy transfer discharge of each battery unit in the large current balance charging and discharging process of charging process in the battery pack; And this device independently external charger system and battery cell management module integration is integrated, so that more lightweight of charging system, microminiaturization.

The technology used in the present invention solution

Basis in the multi-unit battery series connection arranges whole Battery pack master control administration module, again extension set administration module in parallel on each element cell.Each module has address separately, and adopts the mutual communication of isolated 485 bussing techniques between each module.(concrete structure is seen Fig. 1)

The major function of master control administration module and principle:

Manage the discharging current of whole Battery pack, (this part is equivalent to the part before the injectron of traditional switch power supply is simplified a part that is merged into the master control administration module for each extension set administration module provides the high-tension current of certain power, realized between each battery unit in the situation that do not cut off the purpose of cascaded structure charged in parallel and balance charge/discharge), and each extension set module is passed the unified arrangement of the data of coming by isolated 485 buses to be calculated, then give each extension set administration module issuing command, allow the extension set administration module carry out corresponding charging, stop and adjusting the operational motions such as charging current.Provide power supply to whole system after mcu control switch unit is connected electrical network and rectifying and wave-filtering under the mains supply charge mode, switch unit is connected battery pack and is directly provided power supply to system under the battery-powered pattern.Auxiliary power supply partly provides each extension set module self work, charging, the required energy voltage of balance.Serial connection charge part is for providing the serial connection charge electric current of traditional whole Battery pack under the battery pack quick charge mode, in battery pack, there are some unit to reach charging by voltage, just cut off the serial connection charge part at once, remainder is finished the charging process of all battery units by each extension set module.(seeing Fig. 2)

The major function of extension set module:

The parameters such as the voltage of detecting unit battery, capacity, temperature, through the primary Calculation arrangement, then send to the master control administration module by isolated CAN bus, the high-tension current PWM modulation isolation that again the master control administration module is provided is carried out equalizing charge to each element cell with certain electric current after being converted to the low-tension current that each element cell can accept.In the charging operations process, take the charging by voltage as standard, part of module stops charging operations after reaching first charge cutoff voltage according to certain current charges, part of module automatically.Stop charging module and automatically start after being reduced to the cut-off charging voltage under the battery cell voltage nature detecting, charging operations again, so repetitive cycling is until till this battery unit is full of.(seeing Fig. 3)

In discharge process, as when occurring between battery unit energy imbalance or some battery unit near final discharging voltage, automatically start the hf and hv pulse circuit of master control administration module, make the discharge of whole Battery pack and to this part unbalance battery unit charging, to realize the equalization discharge function in the discharge process.

The unit that the charge and discharge balancing pattern that the present invention relates to can guarantee whole battery pack under any circumstance carries out the DIRECT ENERGY transfer type to the unbalance battery unit that is detected efficiently balanced synchronously.

Connection and pass between each unit of each functional module and battery pack is (seeing Fig. 1): whole group of series battery is in parallel with the main management module, also provides high-tension current in parallel to each extension set module when the commutation circuit by the main management inside modules provides electric current to load.The three-phase alternating current 380V electric power of electrical network or two-phase 220V electric power also are transformed to high-tension current after by the rectification of main management module and offer each extension set module.High-tension current between master control administration module and each the extension set module adopts the mode of 2 power line parallels, realizes the purpose of series battery and the isolation of parallel high voltage electric current by the switch transformer of each extension set module.Adopt the round-the-clock large current balance of isolated 485 bus communications (2 data lines, 2 auxiliary power supply lines, 2 high voltage supply lines) between each module, be transformed to high-tension current with whole Battery pack by the master control administration module and offer the discharge of each extension set module, the various states of each extension set module by detecting battery unit are realized with the method that determines each battery unit and whether charge.

Description of drawings

Fig. 1 represents the distributed lithium-ion battery pack managing system schematic diagram of one embodiment of the present of invention.(seeing Fig. 1)

Fig. 2 represents main management module topology diagram of the present invention.

Fig. 3 represents the diversity module topology diagram of each battery unit of the present invention.

Embodiment

The distributed lithium-ion energy storage that the present invention relates to and power battery management system and technology can be used the power-supply systems such as the new forms of energy lithium-ion energy storage battery system such as large industrialized wind energy, solar energy and the large powerful mobile vehicle-mounted electric automobile lithium-ion-power cell group system of capacity and many emergency power supply UPS, communication base station and electric power, electric tool widely.This invention has been finished electric automobile lithium-ion-power cell group successively in the actual test of different capabilities with power requirements and different working conditions.Test shows, real data has reached the requirement of all technical in the technological frame of the present invention's design substantially.

Claims (5)

1. the lithium ion power of a multiple unit series connection use and energy-storage battery group fills, discharge distributed, digitlization and dynamic battery management system, increased the master control administration module in parallel with whole Battery pack at the lithium ion power of many battery unit series connection uses and the basis of energy-storage battery group, and the extension set administration module in parallel with each battery unit, parallel join high-power high voltage energy transmits circuit and isolated 485 bus signals transmission circuit (the also bus line of the same structures such as available 485) (seeing accompanying drawing 1) between master control administration module and each the extension set administration module.

2. management system according to claim 1, it is characterized in that adopting between master control administration module and the extension set administration module method in parallel, in the mode of switch transformer hf and hv pulse electric current isolation transferring energy, realize that series battery does not change in the situation of cascaded structure the separately purpose of management of every unit charged in parallel and every unit.

3. management system according to claim 1, it is characterized in that master control administration module and the communication between the extension set administration module adopt the mode of isolated 485 buses (also can be 485 etc. similar bus mode), the high-power commutation circuit of the inner employing of master control administration module, total output of battery pack and power network current are converted to the required high-tension current of each extension set administration module, each extension set module is converted to the required action of low-voltage pulse direct current of each element cell charging to high-tension current again, reach integration charger, realized the purpose that charging system is integrated and microminiaturized.

4. battery management system according to claim 1, the circuit that it is characterized in that the inner MCU of the employing control of master control administration module high-power IGBT, charging, the discharge process of the whole Battery pack of strict control have been realized the in working order lower purpose that is in all the time the optimal equalization operating state of each element cell.

5. battery management system according to claim 1, it is characterized in that each extension set administration module adopts bi-directional DC-DC, increase the method for MCU Detection ﹠ Controling unit, realized controlling the purpose that each element cell charging and discharging currents is controlled and whether discharged and recharged, really realized the purpose of the round-the-clock equilibrium of energy transfer type.

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