CN110829530B - Battery pack performance balancing method and system - Google Patents

Battery pack performance balancing method and system Download PDF

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CN110829530B
CN110829530B CN201911113975.4A CN201911113975A CN110829530B CN 110829530 B CN110829530 B CN 110829530B CN 201911113975 A CN201911113975 A CN 201911113975A CN 110829530 B CN110829530 B CN 110829530B
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battery
sub
battery pack
module
performance
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CN110829530A (en
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蔡涛
魏芃
韩云飞
周敏
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Huazhong University of Science and Technology
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0013—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries acting upon several batteries simultaneously or sequentially
    • H02J7/0014—Circuits for equalisation of charge between batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4207—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells for several batteries or cells simultaneously or sequentially
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/425—Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/425—Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing
    • H01M2010/4271—Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Abstract

The invention discloses a battery pack performance balancing method and a system, wherein the method comprises the following steps: synchronously acquiring electrical information of each battery monomer in a battery pack to be balanced, and calculating performance indexes to be balanced of each battery module, wherein each battery module comprises a plurality of adjacent battery monomers, partial battery monomers are overlapped between every two adjacent battery modules, and each battery monomer is grouped; and determining the battery module with the maximum index deviation threshold in each sub battery pack based on the performance index of each battery module, controlling other battery modules in the sub battery pack to charge the battery module or controlling the battery module to discharge to other battery modules, and repeating the steps until the performance in each sub battery pack is balanced, wherein each sub battery pack comprises a plurality of adjacent battery modules without overlapping of battery monomers, each two adjacent sub battery packs are respectively provided with a part of overlapping of battery monomers, and each battery module is grouped. The invention adopts staggered equalization, and can efficiently and reliably achieve the performance equalization of the whole low-voltage battery pack.

Description

Battery pack performance balancing method and system
Technical Field
The invention belongs to the field of electrochemical energy storage, and particularly relates to a battery pack performance balancing method and system.
Background
The increasingly deficient traditional energy sources and the increasingly worsening environment greatly promote the development of new energy sources, the renewable energy sources represented by wind energy and solar energy have intermittency and volatility, and the direct grid connection of the renewable energy sources can bring remarkable influence on the safe and stable operation of a power grid. The large-scale energy storage technology can effectively solve the problem, and has important significance for 'peak clipping and valley filling' of the power system, improving the safety and stability of the power system and reducing the power supply cost. In order to meet the voltage and capacity level requirements of large-scale energy storage systems, a large number of battery cells are generally required to be connected in series and in parallel to work in groups. However, in the working process of the battery pack, the inconsistency of each battery cell is further enlarged due to the difference of the manufacturing process and the application environment, the battery has different aging degrees, the battery cell with fast performance decay can reduce the capacity utilization rate and the service life of the whole battery pack, even the battery cell fails, the whole battery pack cannot work normally, and in extreme cases, safety accidents can be caused.
Therefore, Battery balancing becomes one of important functions of a Battery Management System (BMS). At present, most of research focuses on solving the problem of inconsistency of battery cells by an energy transfer balancing method, that is, electric energy of a battery cell with a high State of Charge (SoC) is transferred to a battery cell with a low SoC, that is, active balancing is performed. From the topology point of view, existing equalization systems include centralized and distributed: the centralized equalization system adopts a central control module to perform equalization control on one equalization module, and the distributed equalization system adopts a master-slave control module with a layered structure to perform equalization control on a plurality of equalization modules. However, neither the centralized equalization system nor the distributed equalization system can achieve the staggered connection between the equalization modules, and each equalization module can only perform equalization management on each battery cell. For a battery pack with a low cell voltage or a wide voltage platform, such as a liquid metal battery, the normal operating voltage of the cell is even lower than 1V, and under the limitation of sampling and estimation accuracy, the topologies of the two conventional equalization systems cannot ensure the reliability of equalization control, and many currently well-developed integrated chips for equalization control cannot be used, such as LTC3300 of ling corporation, and the minimum cell voltage required by the primary grid drive is 2V.
Disclosure of Invention
The invention provides a battery pack performance balancing method and system, which are used for solving the technical problem of poor balancing reliability of a low-voltage battery pack caused by centralized or distributed adoption of the existing battery pack performance balancing method.
The technical scheme for solving the technical problems is as follows: a battery pack performance balancing method comprises the following steps:
s1, synchronously acquiring electrical information of each battery monomer in the battery pack to be balanced to calculate the performance index to be balanced of each battery module, wherein each battery module comprises a plurality of adjacent battery monomers, part of the battery monomers are overlapped between every two adjacent battery modules, and each battery monomer is grouped;
and S2, determining the battery module with the maximum index deviation threshold value in each sub battery pack based on the performance index of each battery module, controlling other battery modules in the sub battery pack to charge the battery module or controlling the battery module to discharge to other battery modules, and repeating S1 until the performance in each sub battery pack is balanced, wherein each sub battery pack comprises a plurality of adjacent battery modules without overlapping battery monomers, each two adjacent sub battery packs are partially overlapped with the battery monomers, and each battery module is grouped.
The invention has the beneficial effects that: the method comprises the following steps of firstly collecting electric information such as voltage, balanced current and the like of each battery monomer, calculating SoC of each battery monomer and/or each battery module, and outputting a balanced driving signal according to a balanced control method, wherein the balanced control method specifically comprises the following steps: firstly, grouping each battery monomer in a battery pack, for example, obtaining M sub-battery packs, wherein each sub-battery pack comprises M adjacent battery modules without overlapping of the battery monomers, the battery pack is divided into M groups of M adjacent battery monomers connected in series by N sections (the battery pack contains N battery monomers, each battery module comprises N battery monomers), each two adjacent sub-battery packs are respectively overlapped by partial battery monomers, each battery module is grouped, and the sub-battery packs are formed based on the grouping method of each battery module so as to perform staggered management on space between the battery modules; in the further management, according to the deviation between the SoC of each battery module and the average SoC of the corresponding sub-battery packs, the intra-pack charging and discharging control of the battery module with the largest deviation in one control period is realized, and the intra-pack non-dissipation and bidirectional balance management of the M battery modules by each sub-battery pack is realized. The method adopts staggered management, can efficiently and reliably achieve the performance balance of the whole battery pack, solves the problem of inconsistent battery charge states, improves the capacity utilization rate of the battery pack, and prolongs the cycle life of the battery pack. Compared with the traditional centralized and distributed equalization methods, the method can improve the equalization reliability under the limitation of sampling and estimation precision, and the staggered equalization method is more compatible with the mature integrated chip for equalization control in the market at present.
On the basis of the technical scheme, the invention can be further improved as follows.
Further, the performance index to be balanced is SOC balance or voltage balance.
The invention has the further beneficial effects that: the SoC can directly reflect the electric quantity (essence) of the battery monomer, and the voltage can indirectly reflect the electric quantity (essence) of the battery monomer, so that the SoC or the voltage is adopted as a balance index, and the balance reliability is high.
Further, each battery module comprises n adjacent battery monomers, and each battery monomer in the second to last-but-second battery monomers is at least divided into two different battery modules.
The invention has the further beneficial effects that: the number of the battery monomers in each battery module is the same, so that the grouping structure of the whole battery pack is simple, and each battery monomer in the second to last-but-second battery monomers is at least divided into two different battery modules, so that the battery monomers are fully associated, and the balancing efficiency and precision are improved.
Furthermore, each battery cell in the second to the last-but-one battery cells is divided into at most n different battery modules.
The invention has the further beneficial effects that: the number of the battery monomers in each battery module is the same and is n, so that each battery monomer group meets the condition that each battery module comprises n adjacent battery monomers, and each battery monomer in the second to last second battery monomers is at least divided into two different battery modules; on the premise that partial battery monomers are overlapped between every two adjacent battery modules and are grouped, each battery monomer in the second to last-but-one battery monomers is divided into at most n different battery modules so as to reduce the associated redundancy and ensure the balancing efficiency.
Further, each of the second to penultimate battery cells is divided into at least two different sub-battery packs.
The invention has the further beneficial effects that: when the battery modules are grouped to form a plurality of sub-battery packs, on the premise of ensuring that each sub-battery pack comprises a plurality of adjacent battery modules without overlapping of battery monomers, each two adjacent sub-battery packs are respectively overlapped with a part of battery monomers, and each battery module is grouped, each battery monomer in the second to last second battery monomers is at least divided into two different sub-battery packs, so that the balance effect of the battery pack is further fully improved.
Further, each sub-battery pack includes the same number of battery modules.
The invention has the further beneficial effects that: each sub-battery pack comprises the same number of battery modules, and the calculation complexity is low, so that the control is convenient.
Further, the S2 includes:
calculating the index average value of each sub battery pack based on the performance index to be balanced of each battery module in each sub battery pack;
calculating the deviation between the performance index to be equalized of each battery module in the sub-battery pack and the index mean value, if the deviation corresponding to each battery module in the sub-battery pack is smaller than the deviation threshold value, completing equalization, otherwise, controlling the battery module corresponding to the maximum deviation to discharge to other battery modules of the sub-battery pack or controlling other battery modules in the sub-battery pack to charge the battery module corresponding to the maximum deviation, and repeating S1.
The invention also provides a battery pack performance balancing system, which comprises:
the control processor is used for generating a control signal for controlling other battery modules in each sub battery pack to charge the battery module with the maximum index deviation threshold or controlling the battery module with the maximum index deviation threshold to discharge to other battery modules by adopting any battery pack performance balancing method;
and one end of the equalizer corresponding to each sub battery pack is electrically connected with each battery module in the sub battery pack, one end of the equalizer is connected with two ends of the sub battery pack, and the other end of the equalizer is also in communication connection with the control processor and is used for realizing equalization control based on the control signal of the sub battery pack generated by the control processor.
The invention has the beneficial effects that: the staggered equalization system of the invention is based on the staggered equalization method, bundles a plurality of low-voltage batteries connected in series to be equivalent to high-voltage batteries, solves the problem of grouping inconsistency of the low-voltage batteries through staggered management, improves the equalization reliability under the limitation of sampling and estimation precision, and is more compatible with the mature integrated chip for equalization control in the current market.
Further, the voltage of each battery cell in the battery pack is less than 1.2V.
The invention also provides a storage medium, wherein the storage medium is stored with instructions, and when the instructions are read by a computer, the computer is enabled to execute any one of the battery pack performance balancing methods.
Drawings
Fig. 1 is a flow chart of a battery performance balancing method according to an embodiment of the present invention;
fig. 2 is a schematic diagram of a staggered equalization scheme for a battery pack according to an embodiment of the present invention;
FIG. 3 is a comparison diagram illustrating various equalization schemes provided by an embodiment of the present invention;
fig. 4 is a schematic diagram of the staggered equalization of a group of 12 low-voltage batteries according to an embodiment of the present invention;
fig. 5 is a diagram of the equalization effect corresponding to fig. 4.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
Example one
A method 100 for balancing battery performance, as shown in fig. 1, includes:
step 110, synchronously acquiring electrical information of each battery monomer in the battery pack to be balanced to calculate performance indexes to be balanced of each battery module, wherein each battery module comprises a plurality of adjacent battery monomers, part of the battery monomers are overlapped between every two adjacent battery modules, and each battery monomer is grouped;
step 120, determining the battery module with the maximum index deviation threshold value in each sub battery pack based on the performance index of each battery module, controlling other battery modules in the sub battery pack to charge the battery module or controlling the battery module to discharge to other battery modules, and repeating step 110 until the performance in each sub battery pack is balanced, wherein each sub battery pack comprises a plurality of adjacent battery modules without overlapping of battery monomers, each two adjacent sub battery packs are partially overlapped with the battery monomers, and each battery module is grouped.
Grouping the battery packs, wherein each battery module comprises a plurality of adjacent battery monomers, and partial battery monomers are overlapped between every two adjacent battery modules so as to ensure that every two adjacent battery monomers are at least in one same battery module and each battery monomer is grouped, thereby ensuring that all the battery modules are related.
In step 120, based on the performance index of each battery module in each sub-battery pack, the battery module with the maximum performance index deviation threshold in the sub-battery pack is determined, and other battery modules in the sub-battery pack are controlled to charge the battery module or the battery module is controlled to discharge to other battery modules in the sub-battery pack. And repeating the step 110 until the performance indexes of all the battery modules in each sub-battery pack are smaller than the threshold value, and at the moment, the battery pack to be balanced achieves performance balance.
Specifically, for example, SoC (State of Charge, also called remaining battery capacity) of each battery module is used as a performance index, a deviation between SoC of each battery module and an average SoC of the corresponding sub battery packs is calculated and compared, the deviation corresponding to each battery module is compared with a given value, all battery modules are smaller than the given value, that is, equalization is completed, if one or more deviation corresponding to the battery module is not smaller than the given value in any one of the sub battery packs, Charge and discharge equalization control is performed on the battery module with the largest deviation index, specifically, the battery module corresponding to the largest deviation is determined from the sub battery packs, if SoC of the battery module is larger than the average SoC of the sub battery packs, the battery module is controlled to discharge the sub battery packs, otherwise, the sub battery packs are controlled to Charge the battery modules, and step 110 is repeated, so that each sub battery pack independently performs equalization control management, however, due to the special grouping mode of the invention, the SOC of each monomer in the battery pack to be balanced can be efficiently and reliably enabled to reach the preset balancing effect finally.
It should be noted that, each battery cell in the battery pack is connected in series, and the battery pack is used for providing electric energy for electric equipment. In addition, each two adjacent sub-battery packs have a part of the battery cells overlapped, but the invention is not limited to each two adjacent sub-battery packs.
The method comprises the following steps of firstly, collecting electric information such as voltage, balanced current and the like of each battery monomer, calculating SoC of each battery monomer and/or each battery module, and outputting balanced driving signals according to a balanced control method, wherein the balanced control method specifically comprises the following steps: firstly, grouping each battery monomer in a battery pack, wherein each battery module comprises a plurality of adjacent battery monomers, each two adjacent battery modules are partially overlapped by the battery monomers, each battery monomer is grouped, for example, as shown in fig. 2, M sub-battery packs are obtained, each sub-battery pack comprises M adjacent battery modules without overlapping of the battery monomers, namely, the battery pack is divided into M groups of adjacent N groups of serially-connected battery monomers (the battery pack contains N battery monomers, each battery module comprises N battery monomers), each two adjacent sub-battery packs are partially overlapped by the battery monomers, each battery module is grouped, and the sub-battery packs are formed based on the grouping method of the battery modules so as to perform staggered management on the space between the battery modules; in the management process, according to the deviation between the SoC of each battery module and the average SoC of the corresponding sub-battery packs, the intra-pack charging and discharging control of the battery module with the largest deviation in one control period is realized, and the intra-pack non-dissipation and bidirectional balance management of the M battery modules by each sub-battery pack is realized. The method adopts the staggered management of the single batteries, can efficiently and reliably achieve the performance balance of the whole battery pack, solves the problem of inconsistent battery charge states, improves the capacity utilization rate of the battery pack, and prolongs the cycle life of the battery pack.
The method has an application effect obviously superior to that of the existing centralized or distributed equalization method for the low-voltage battery, and solves the problems that the equalization reliability is low and an integrated chip for equalization control cannot be used so as to cause inconvenience (the voltage of the low-voltage battery is below 1.2V, and the low-voltage battery is a liquid metal battery, for example) due to the fact that the low-voltage battery is subjected to group error equalization under the limitation of sampling and estimation accuracy.
Compared with the traditional centralized and distributed equalization methods, the staggered equalization method can solve the problem of inconsistent grouping of the low-voltage batteries, improves the equalization reliability under the limitation of sampling and estimation precision, and is more compatible with the mature integrated chip for equalization control in the current market.
Preferably, the performance indexes to be equalized are SOC equalization and voltage equalization.
Preferably, each battery module comprises n adjacent battery cells, and each battery cell of the second to penultimate battery cells is divided into at least two different battery modules.
The number of the battery monomers in each battery module is the same, so that the grouping structure of the whole battery pack is simple, and each battery monomer in the second to last-but-second battery monomers is at least divided into two different battery modules, so that the battery monomers are fully associated, and the balancing efficiency and precision are improved.
Preferably, each of the second to penultimate battery cells is divided into at most n different battery modules.
The number of the battery monomers in each battery module is the same and is n, then each battery monomer group meets the premise that each battery module group comprises n adjacent battery monomers, each battery monomer in the second to last but one battery monomer is at least divided into two different battery modules, part of the battery monomers are overlapped between every two adjacent battery modules, and each battery monomer is divided into n different battery modules, so that the correlation redundancy is reduced, and the balance efficiency is ensured.
Preferably, each of the second to penultimate battery cells is divided into at least two different sub-battery packs.
When the battery modules are grouped to form a plurality of sub-battery packs, on the premise of ensuring that each sub-battery pack comprises a plurality of adjacent battery modules without overlapping of battery monomers, each two adjacent sub-battery packs are respectively overlapped with a part of battery monomers, and each battery module is grouped, each battery monomer in the second to last second battery monomers is at least divided into two different sub-battery packs, so that the balance effect of the battery pack is further fully improved.
Preferably, each of the sub-battery packs includes the same number of battery modules, but is not limited to the same.
Each sub-battery pack comprises the same number of battery modules, and the calculation complexity is low, so that the control is convenient.
Preferably, step 120 includes:
calculating the index average value of each sub battery pack based on the performance index to be balanced of each battery module in each sub battery pack;
calculating the deviation between the performance index to be equalized of each battery module in the sub-battery pack and the index mean value, if the deviation corresponding to each battery module in the sub-battery pack is smaller than the deviation threshold value, equalizing, otherwise, controlling the battery module corresponding to the maximum deviation to discharge to other battery modules of the sub-battery pack or controlling other battery modules in the sub-battery pack to charge the battery module corresponding to the maximum deviation, and repeatedly executing the step 110.
For example, the deviation between the SoC of each battery module and the average SoC of the corresponding sub-battery module is: the sum of squares of differences between the SoC of each battery module and the average SoC of the corresponding sub-battery module, if the deviation corresponding to the ith battery module is calculated, is expressed as:
Figure GDA0003021437970000091
m is the number of battery modules in a sub-battery pack in which the ith battery module is located.
To better illustrate the advantages of the present invention, three equalization methods are described below:
as shown in a in fig. 3, in a schematic diagram of a conventional centralized balancing system, a centralized balancing module performs balancing management on each single battery, and the centralized balancing module is susceptible to a single point of failure and adversely affects the reliability, expansibility, and flexibility of the entire system; as shown in b in fig. 3, in the schematic diagram of the conventional distributed equalization system, each equalization module performs equalization management on each battery cell managed by the equalization module, and the distributed equalization system is more suitable for a long-string battery pack than a centralized equalization system.
However, for a low-voltage single battery pack, such as a liquid metal battery, the conventional centralized equalization system and the conventional distributed equalization system still need to control each single battery, which has high requirements on sampling and estimation accuracy of the system, and is not suitable for some mature integrated chips for equalization control, such as LTC3300 of the ling company. As shown in c in fig. 3, the schematic diagram of the interleaved balancing system includes three interleaved balancing modules, one balancing module performs balancing management on one sub-battery pack, and the balancing modules are connected in an interleaved manner. The staggered equalization method is suitable for a battery pack with low battery monomer voltage, a group of adjacent battery monomers connected in series are subjected to charge and discharge control simultaneously in each control period, the sampling and estimation accuracy requirements of the system are reduced, and various mature integrated chips for equalization control are compatible by flexibly configuring the equalization control method, so that the reliability and compatibility of the equalization system are improved, and the example is as follows:
as shown in FIG. 4, a schematic diagram of an interleaved equalizing system of 12 low battery cell voltages corresponding to FIG. 3, taking LTC3300 as an equalizing module as an example, divides 12 battery cells into 10 battery modules, wherein the 1 st-3 battery cells are the 1 st battery module, the 4 th-6 battery cells are the 2 nd battery module, the 7 th-9 battery cells are the 3 rd battery module, the 10 th-12 battery cells are the 4 th battery module, the 2 nd-4 battery cells are the 5 th battery module, the 5 th-7 battery cells are the 6 th battery module, the 8 th-10 battery cells are the 7 th battery module, and the 3 rd-5 battery cells are the 8 th battery moduleThe battery module, the 6 th to 8 th battery monomers are the 9 th battery module, the 9 th to 11 th battery monomers are the 10 th battery module, the equalizing module 1 manages the 1 st to 4 th battery modules, the equalizing module 2 manages the 5 th to 7 th battery modules, and the equalizing module 3 manages the 8 th to 10 th battery modules. In each control cycle, the deviation indexes of the battery modules are compared, for example, the deviation index of the 1 st battery module is
Figure GDA0003021437970000101
The deviation index of the 5 th battery module is
Figure GDA0003021437970000102
The deviation index of the 8 th battery module is
Figure GDA0003021437970000103
Wherein, SoCiIs the SOC of the ith cell. Obtaining a group with the largest deviation index, for example, the 1 st group of battery modules, comparing the average SoC of the 1 st group of battery modules with the average SoC of the sub-battery group consisting of the 1 st to 4 th groups of battery modules managed by the balancing module 1, if the average SoC is larger than the average SoC, the 1 st group of battery modules performs discharge control on the sub-battery group managed by the balancing module 1, and if the average SoC is smaller than the average SoC, the sub-battery group managed by the balancing module 1 performs charge control on the 1 st group of battery modules until the deviation indexes of all the battery modules are smaller than the initial set value epsilon (only one set value epsilon is set for the whole battery group).
As shown in fig. 5, in the balancing effect diagram of the 12-low battery cell voltage interleaved balancing system corresponding to fig. 4, taking the balancing control of 12 battery cells as an example, the initial SoC of each battery cell is 30% to 55%, the battery cell capacity is 100Ah, the balancing current is 8A, and the minimum deviation index given value is 8%. Therefore, within a certain time, the deviation of the SoC of each battery monomer is gradually reduced and stabilized within the minimum deviation index set value, so that the staggered equalization system and the control method provided by the method can solve the problem of battery inconsistency, and the equalization stability is proved, so that the reliability and the adaptability of the equalization system of the low battery monomer voltage are further improved.
Example two
A battery pack performance equalization system, comprising: and the control processor and the corresponding equalizer of each sub battery pack. The control processor is used for generating a control signal for controlling other battery modules in each sub-battery pack to charge the battery module with the maximum index deviation threshold or controlling the battery module with the maximum index deviation threshold to discharge to other battery modules by adopting any battery pack performance balancing method; and one end of the equalizer corresponding to each sub battery pack is electrically connected with each battery module in the sub battery pack, one end of the equalizer is connected with two ends of the sub battery pack, and the other end of the equalizer is also in communication connection with the control processor and is used for realizing equalization control based on the control signal of the sub battery pack generated by the control processor.
The control processor inputs the electrical information of each battery cell and outputs a control signal to calculate and generate an equalization strategy in a control period, and outputs the control signal to drive each equalizer to realize the function of energy management.
Preferably, the voltage of each battery cell in the battery pack is less than 1.2V, and LTC3300 can be used as an equalizer. It should be noted that the system can be applied to high-voltage and low-voltage battery packs with high precision, and particularly, when the battery pack to be equalized is a low-voltage battery pack, the system has an obvious excellent equalization effect compared with the existing centralized or distributed equalization system.
The staggered equalization system can solve the problem of grouping inconsistency of the low-voltage batteries, improves the equalization reliability under the limitation of sampling and estimation precision, and is more compatible with the mature integrated chip for equalization control in the current market.
The related technical solution is the same as the first embodiment, and is not described herein again.
EXAMPLE III
A storage medium having instructions stored therein, which when read by a computer, cause the computer to execute any one of the battery performance balancing methods described in the first embodiment above.
The related technical solution is the same as the first embodiment, and is not described herein again.
It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims (8)

1. A method for balancing battery pack performance, comprising:
s1, synchronously acquiring electrical information of each battery monomer in the battery pack to be balanced to calculate the performance index to be balanced of each battery module, wherein each battery module comprises a plurality of adjacent battery monomers, part of the battery monomers are overlapped between every two adjacent battery modules, and each battery monomer is grouped;
s2, determining the battery module with the maximum index deviation threshold value in each sub battery pack based on the performance index of each battery module, controlling other battery modules in the sub battery pack to charge the battery module or controlling the battery module to discharge to other battery modules, and repeating S1 until the performance in each sub battery pack is balanced, wherein each sub battery pack comprises a plurality of adjacent battery modules without overlapping battery monomers, each two adjacent sub battery packs are partially overlapped with the battery monomers, and each battery module is grouped;
each battery module comprises n adjacent battery monomers, and each battery monomer in the second to last-but-second battery monomers is at least divided into two different battery modules;
the S2 includes:
calculating the index average value of each sub battery pack based on the performance index to be balanced of each battery module in each sub battery pack;
calculating the deviation between the performance index to be equalized of each battery module in the sub-battery pack and the index mean value, if the deviation corresponding to each battery module in the sub-battery pack is smaller than a deviation threshold value, completing equalization, otherwise, controlling the battery module corresponding to the maximum deviation to discharge to other battery modules of the sub-battery pack or controlling other battery modules in the sub-battery pack to charge the battery module corresponding to the maximum deviation, and repeating S1;
in the calculation of the deviation between the performance index to be equalized of each battery module in the sub-battery pack and the index mean value, the deviation corresponding to the ith battery module is represented as:
Figure FDA0003047182550000011
in the formula (I), the compound is shown in the specification,
Figure FDA0003047182550000012
represents the index mean value, SoC, of the sub-batteryi、SoCjThe performance indexes to be equalized of the ith battery module and the jth battery module in the sub-battery pack are respectively, and M is the number of the battery modules in the sub-battery pack.
2. The battery pack performance balancing method according to claim 1, wherein the performance index to be balanced is SOC balance or voltage balance.
3. The battery pack performance balancing method according to claim 1, wherein each of the second to penultimate battery cells is divided into at most n different battery modules.
4. The battery pack performance balancing method according to claim 1, wherein each of the second to penultimate battery cells is divided into at least two different sub-battery packs.
5. The battery pack performance balancing method according to claim 1, wherein each sub battery pack includes the same number of battery modules.
6. A battery pack performance equalization system, comprising:
the control processor is used for generating a control signal for controlling other battery modules in each sub-battery pack to charge the battery module with the largest index deviation threshold or controlling the battery module with the largest index deviation threshold to discharge the other battery modules by adopting the battery pack performance balancing method as claimed in any one of claims 1 to 5 for the battery pack to be balanced;
and one end of the equalizer corresponding to each sub battery pack is electrically connected with each battery module in the sub battery pack, one end of the equalizer is connected with two ends of the sub battery pack, and the other end of the equalizer is also in communication connection with the control processor and is used for realizing equalization control based on the control signal of the sub battery pack generated by the control processor.
7. The system for equalizing performance of battery packs according to claim 6, wherein the voltage of each battery cell in the battery pack is less than 1.2V.
8. A storage medium having stored therein instructions, which when read by a computer, cause the computer to execute a battery performance balancing method according to any one of claims 1 to 5.
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