CN102769316B - Battery selective equalization method - Google Patents
Battery selective equalization method Download PDFInfo
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- CN102769316B CN102769316B CN201210251925.4A CN201210251925A CN102769316B CN 102769316 B CN102769316 B CN 102769316B CN 201210251925 A CN201210251925 A CN 201210251925A CN 102769316 B CN102769316 B CN 102769316B
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- battery
- cell
- equalizing circuit
- battery cell
- measurement
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Abstract
The invention discloses a battery selective equalization method. The method comprises the following steps of: firstly, measuring battery voltage; secondly, identifying batteries which are required to be equalized; and finally, configuring equalization circuits according to an identification result. In the step of identifying the batteries which are required to be equalized, the equalization circuits are configured for the batteries with high tolerance according to the characteristic that the capacity tolerance of the batteries is in accordance with normal distribution. The battery selective equalization method has the advantages that a one-to-one equalization circuit configuration circuit can be achieved by configuring a small number of equalization circuits, the equalization performance of the batteries can be ensured, and the cost of the equalization circuits can be greatly reduced.
Description
Technical field
What the present invention relates to is a kind of method of carrying out storage battery equilibrium, specifically, is a kind of method that single battery in series connection or intermodule carry out storage battery equilibrium selectively.Belong to battery energy storage and battery management technical field.
Background technology
Battery energy storage is the important technical of new forms of energy access in electric automobile and intelligent grid.The management of electrokinetic cell in electric automobile and equilibrium are the keys that ensures electric automobile flying power and battery, and battery energy storage is the effective way that solves new-energy grid-connected difficulty and the wind-powered electricity generation problem of " abandoning wind " for smooth wind power and photovoltaic generation power.The application of extensive battery energy storage in electrical network can only transmit by changing electric energy the history that can not store, brings revolutionary impact to electrical production and operation, greatly promotes the development of intelligent grid.
Due to the monomer voltage lower (being less than 5VDC) of battery, finite capacity (being generally no more than 500Ah), therefore in high capacity cell energy-storage system, current way is first by the series connection to battery cell, (<100VDC) battery module that obtains having certain voltage; Be battery pile by multiple battery module series connection again, stack voltage is battery system direct voltage, mostly between 300-1100VDC.
Because each battery cell electric current in series circuit equates, and there is certain difference in the capacity of each battery cell, and when charging, first the battery that capacity is less is full of, and continues charging may cause the over-charging of battery that capacity is less; When electric discharge, first the battery that capacity is less discharges, and continues electric discharge and may cause battery that capacity is less to cross to put.Thereby cause the capacity of the battery cell that capacity is less and the loss in life-span, and form vicious circle.Therefore, the direct connection of wire has inevitably caused the generation of battery " short-board effect ", has seriously limited the bulk life time of battery system.Battery cell series connection quantity at battery system is many, direct voltage high " short-board effect " more outstanding.
Balanced control is the critical function of battery management system, is the key link that solves battery " short-board effect ".Balanced scheme has multiple, is divided into charge balancing, equalization discharge and dynamic equalization according to control mode.According to the processing mode of energy being divided into the equilibrium of energy loss type and active energy transfer equilibrium.Wherein active energy transfer equilibrium can be divided into again cascade structure and absolute construction according to structure, is divided into monomer-monomer and monomer-group according to energy flow object.No matter above-mentioned which kind of equalizing structure and control mode, is all required to be each battery cell (module) according to 1:1 configuration equalizing circuit, and circuit repeatability is high, cost is high.In extensive battery energy storage system, amount of monomer may reach scale up to ten thousand, and the problem of balanced cost is very outstanding.
Summary of the invention
The present invention is directed to the deficiency that prior art exists, propose a kind of selectivity equalization methods, can configure a small amount of equalizing circuit and reach the effect of 1:1 configuration equalizing circuit.The method can greatly reduce equalizing circuit cost in ensureing battery balanced performance.
For achieving the above object, the present invention realizes by the following technical solutions:
Cell selective equalization methods of the present invention, first carry out the measurement of cell voltage, then the balancing battery of needs is carried out to identification, carry out again the configuration of equalizing circuit according to identification result, wherein: described the balancing battery of needs is carried out to identification, being the feature that meets normal distribution according to battery capacity deviation, is only the cell arrangement equalizing circuit that deviation is large.
Further:
1, the measurement of cell voltage
By battery module is discharged and recharged, make the state of battery module in being about to be full of (SOC>0.85) or will being discharged (SOC<0.15).Then carry out the measurement of each battery cell (module) voltage.This measurement can be that on-line measurement can be also off-line measurement.For fear of impact and the less measure error of disturbing factor, in measurement, need to carry out filtering processing.Filtering mode can be that analog form can be also digital filtering, considers the consistency that ensures each channel filtering parameter, preferentially gets digital filtering mode.Suppose that battery module connected by N battery cell, the series voltage data of each battery cell recording are U
1, U
2, U
3..., U
n.Voltage measurement precision is advisable higher than 5mV.
2, the identification of the battery to needs equilibrium
To the voltage data U recording
1, U
2, U
3..., U
naveraged, obtaining its mean value is U
avg.
Asking for each magnitude of voltage and mean value U
avgdeviation delta U
i.
ΔU
i＝|U
i-U
avg|
In formula, i=1,2,3 ..., N.
To deviation delta U
iaccording to sorting in proper order from big to small.
In the identification process of the battery to needs equilibrium, ignore battery due to the capacity attenuation that faults itself or external factor cause, only consider the capacity discreteness causing due to material and the production process of battery.Because the deviation of capacity generally can be controlled in 2%-3%, and Normal Distribution rule, therefore most battery does not need to carry out equilibrium.Can configure equalizing circuit quantity M, M=(10%-20% according to the battery cell quantity of 10%-20%) N, this is reduced the cost that makes equalizing circuit greatly.According to after the quantity M of this ratio-dependent equalizing circuit, find out from big to small front M corresponding battery cell according to above-mentioned inclined to one side extent, this M battery cell is needs balanced battery cell.
3, the configuration of equalizing circuit
Equalizing circuit need to adopt the two-way DC/DC of energy or two-way DC/AC type circuit, and the equalizing circuit of energy cascade transmission can not be suitable for.Equalizing circuit is connected in parallel on the two ends of battery cell, and the physical configuration that has two kinds of methods to realize between battery cell and equalizing circuit connects: static configuration and dynamic-configuration.
While taking static configuration mode, according to above-mentioned identification result, manually equalizing circuit is connected by wire with battery cell.While taking dynamic-configuration, equalizing circuit and need the electrical connection between balanced battery cell to realize by controllable electronic switch or relay.
4, equalizing circuit work
After configuring the annexation of equalizing circuit and battery cell, no matter battery module can carry out balanced operation in online (discharging and recharging) or off-line state.Balance policy can adopt the mode such as electric voltage equalization, SOC equilibrium.
With respect to other technologies, the equalizing circuit quantity configuring in the present invention is greatly reduced, and is the 10-20% of prior art scheme, not reducing under the prerequisite of portfolio effect, has greatly reduced balanced cost.
The present invention can be applied to and allly need to carry out balanced occasion to storage battery, as electric bicycle, electric automobile, battery energy storage device etc. are extremely safeguarded the occasion of being very concerned about to accumulator property.
Embodiment
Below embodiments of the invention are elaborated: the present embodiment is implemented under taking technical solution of the present invention as prerequisite, provided detailed execution mode and concrete operating process, but protection scope of the present invention is not limited to following embodiment.
The present embodiment adopts following steps to realize:
1, the measurement of cell voltage
In concrete enforcement, objective for implementation is a ferric phosphate lithium cell module being composed in series by the battery cell of 15 nominal voltage 3.2V, its nominal voltage 48V, capacity 50AH.
10 Ohmic resistances in parallel carry out 0.1C electric discharge to it, adopt 16 passage/16/250kS/s difference isolated form data collecting card NI PXI-6233 to measure its voltage simultaneously.Its voltage measurement precision can reach in 0.2mV.The terminal voltage of 15 battery cells is carried out to continuous 40ms measurement with 10kS/s sample rate, obtain the voltage data sequence that 15*400 is ordered.
15 data sequences that sampling is obtained are removed High-frequency Interference low pass filtered and are involved the notch filter processing of disturbing for power frequency, obtain the terminal voltage data U of 15 battery cells
1, U
2, U
3..., U
15, its precision and confidence level are high compared with initial data.
The identification of the balancing battery 2, needing
15 voltage datas are averaged to process and obtain average voltage U
avg.
Asking for each magnitude of voltage and mean value U
avgdeviation delta U
i.
ΔU
i＝|U
i-U
avg|
For the battery module by 15 battery cell series connection, according to 20% configuration equalizing circuit, need 3 of equalizing circuits.Δ U
ibattery cell corresponding to first three maximum is needs balanced battery cell.
3, the configuration of equalizing circuit
For three battery cells of needs equilibrium, take artificial way at two ends separately equalizing circuit in parallel.Equalizing circuit adopts DC/DC type reversible transducer.Its one end and battery cell parallel connection that need to be balanced, the other end is in parallel with whole battery module two ends.
4, equalizing circuit work
Battery module is placed in to normal operating conditions, and battery management system is according to the real-time voltage value U detecting
1, U
2, U
3..., U
15calculate average voltage U
avg, as U
i>U
avg, control equalizing circuit and make battery cell emit energy to whole battery module, as U
i<U
avg, control equalizing circuit battery cell absorbed energy from whole battery module.Until with deviation be less than 5mV.
With respect to other technologies, the equalizing circuit quantity configuring in the present embodiment is greatly reduced, and is the 10-20% of prior art scheme, not reducing under the prerequisite of portfolio effect, has greatly reduced balanced cost.
Although content of the present invention has been done detailed introduction by above preferred embodiment, will be appreciated that above-mentioned description should not be considered to limitation of the present invention.Read after foregoing those skilled in the art, for multiple amendment of the present invention and substitute will be all apparent.Therefore, protection scope of the present invention should be limited to the appended claims.
Claims (7)
1. a cell selective equalization methods, it is characterized in that: first carry out the measurement of cell voltage, then the battery of needs equilibrium is carried out to identification, carry out again the configuration of equalizing circuit according to identification result, wherein: described the battery of needs equilibrium is carried out to identification, being the feature that meets normal distribution according to battery capacity deviation, is only the cell arrangement equalizing circuit that deviation is large;
Described the battery of needs equilibrium is carried out to identification, is implemented as follows:
To the series voltage data U of each battery cell
1, U
2, U
3..., U
naveraged, obtaining its mean value is U
avg, then ask for each magnitude of voltage and mean value U
avgdeviation delta U
i, to deviation delta U
isort according to order from big to small;
In the identification process of the battery to needs equilibrium, ignore the capacity attenuation that battery causes due to faults itself or external factor, only consider the capacity discreteness causing due to material and the production process of battery, because the Deviation Control of capacity is in 2%-3% and Normal Distribution rule, configure equalizing circuit quantity M according to the battery cell quantity of 10%-20%, M=(10%-20%) N, according to after the quantity M of this ratio-dependent equalizing circuit, find out from big to small front M corresponding battery cell according to above-mentioned inclined to one side extent, this M battery cell is needs balanced battery cell.
2. cell selective equalization methods according to claim 1, is characterized in that: the configuration of described equalizing circuit specifically realizes the equilibrium to battery by two-way DC/DC or DC/AC circuit.
3. cell selective equalization methods according to claim 2, it is characterized in that: described equalizing circuit is connected in parallel on the two ends of battery cell, the physical configuration that has two kinds of methods to realize between battery cell and equalizing circuit connects: static configuration and dynamic-configuration, while wherein taking static configuration mode, according to above-mentioned identification result, manually equalizing circuit is connected by wire with battery cell; While taking dynamic-configuration, equalizing circuit and need the electrical connection between balanced battery cell to realize by controllable electronic switch or relay.
4. according to the cell selective equalization methods described in claim 2 or 3, it is characterized in that: after configuring the annexation of equalizing circuit and battery cell, no matter battery module can carry out balanced operation in online or off-line state.
5. according to the cell selective equalization methods described in claim 1-3 any one, it is characterized in that: the measurement of described cell voltage, specific as follows:
By battery module is discharged and recharged, make the state of battery module in being about to be full of or will be discharged, then carry out the measurement of each battery cell voltage; In measurement, need to carry out filtering processing, suppose that battery module connected by N battery cell, the series voltage data of each battery cell recording are U
1, U
2, U
3..., U
n, voltage measurement precision is higher than 5mV.
6. cell selective equalization methods according to claim 5, is characterized in that: described filtering mode is analog form or digital filtering.
7. cell selective equalization methods according to claim 5, is characterized in that: described measurement is on-line measurement or off-line measurement.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210251925.4A CN102769316B (en) | 2012-07-20 | 2012-07-20 | Battery selective equalization method |
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|---|---|---|---|
| CN201210251925.4A CN102769316B (en) | 2012-07-20 | 2012-07-20 | Battery selective equalization method |
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| CN102769316A CN102769316A (en) | 2012-11-07 |
| CN102769316B true CN102769316B (en) | 2014-10-15 |
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Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104901350B (en) * | 2014-12-26 | 2017-12-26 | 中国船舶重工集团公司第七一九研究所 | A kind of batteries two-stage cascade equalizing system based on common DC bus |
| CN106655338B (en) * | 2016-11-14 | 2019-08-13 | 深圳市科陆电子科技股份有限公司 | A kind of on-off control method for energy-storage system balance module |
| CN107039691A (en) * | 2017-05-02 | 2017-08-11 | 北京诺万电子科技有限公司 | A kind of battery static state, dynamic equalization control method and system |
| CN109756001B (en) * | 2019-03-13 | 2022-03-11 | 北汽福田汽车股份有限公司 | Electric automobile, battery system and balancing method and device thereof |
| CN111725854B (en) * | 2019-03-21 | 2021-06-29 | 宁德时代新能源科技股份有限公司 | Energy storage system and control method and device thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US4331911A (en) * | 1978-05-22 | 1982-05-25 | Park Robert H | Method of equalizing the voltages of the individual cells of storage batteries |
| CN101567574A (en) * | 2009-06-03 | 2009-10-28 | 王创社 | Proportional balancing method for voltage of energy storage device and circuit |
| CN101986508B (en) * | 2010-12-03 | 2013-01-16 | 安徽力高新能源技术有限公司 | Battery equalizing device |
| CN102496979A (en) * | 2011-11-28 | 2012-06-13 | 上海交通大学 | Lithium ion battery pack equalizing circuit with automatic polarity switch |
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