CN116316998A - Bypass balance control method and system applied to energy storage battery - Google Patents

Bypass balance control method and system applied to energy storage battery Download PDF

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Publication number
CN116316998A
CN116316998A CN202310334715.XA CN202310334715A CN116316998A CN 116316998 A CN116316998 A CN 116316998A CN 202310334715 A CN202310334715 A CN 202310334715A CN 116316998 A CN116316998 A CN 116316998A
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China
Prior art keywords
battery pack
balanced
constant
charge
battery
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CN202310334715.XA
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Chinese (zh)
Inventor
刘涛
何凯
徐福斌
宋云庆
刘文军
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Shenzhen Xianyang New Energy Technology Co ltd
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Shenzhen Xianyang New Energy Technology Co ltd
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Priority to CN202310334715.XA priority Critical patent/CN116316998A/en
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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
    • 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
    • H02J7/00032—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries characterised by data exchange
    • H02J7/00036—Charger exchanging data with battery
    • 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
    • H02J7/0016—Circuits for equalisation of charge between batteries using shunting, discharge or bypass circuits
    • 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
    • H02J7/0047—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with monitoring or indicating devices or circuits
    • H02J7/0048—Detection of remaining charge capacity or state of charge [SOC]
    • 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
    • H02J7/0068—Battery or charger load switching, e.g. concurrent charging and load supply
    • 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
    • H02J7/007—Regulation of charging or discharging current or voltage
    • H02J7/00712—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters
    • 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
    • H02J7/007—Regulation of charging or discharging current or voltage
    • H02J7/00712—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters
    • H02J7/00714—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters in response to battery charging or discharging current
    • H02J7/00716—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters in response to battery charging or discharging current in response to integrated charge or discharge current
    • 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
    • H02J7/007—Regulation of charging or discharging current or voltage
    • H02J7/00712—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters
    • H02J7/007182—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters in response to battery voltage
    • 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 provides a bypass balance control method and a bypass balance control system applied to an energy storage battery, wherein the method comprises the following steps: collecting current, voltage and charge state of a battery pack to be balanced in a battery pack string in the charge-discharge process of the battery pack string; acquiring a control strategy; generating a control instruction according to the current, the voltage, the state of charge and the control strategy of the battery pack to be balanced; and controlling the bypass circuit to act according to the control instruction so that one part of charge and discharge current flows through the battery pack to be balanced, wherein the battery pack to be balanced is in a constant current mode, a constant voltage mode, a constant power mode or a constant resistance mode, and the other part of charge and discharge current flows through the bypass circuit. The method controls the battery pack to be balanced to be in different working modes, and can adapt to different balancing demands of the system.

Description

Bypass balance control method and system applied to energy storage battery
Technical Field
The invention belongs to the technical field of battery equalization, and particularly relates to a bypass equalization control method and a bypass equalization control system applied to an energy storage battery.
Background
With the development of battery technology, the requirements of users on the state of charge of the energy storage battery are increasing. For example, lithium iron phosphate batteries typically require hundreds of cells in series, with a single cell having a float voltage of 3.6V. Because a battery pack string is formed by connecting a plurality of battery packs in series and parallel, and one battery pack is obtained by packaging tens of battery cells in series and parallel, even if the battery cells/battery packs are screened in the production and manufacturing process, the number is huge, and the problem of consistency difference cannot be completely avoided. In addition, when there are cases such as mixing of new and old battery packs, the difference in the battery packs causes various problems:
1. series mismatch; referring to fig. 1, the capacities of the three battery packs connected in series in fig. 1 are 10%, 15% and 23%, respectively, and according to the basic characteristics of the series circuit, the available charge states of the battery packs on the series link can only reach the charge state of the weakest battery pack, so that the available capacity of the battery packs on the whole link is only 10%, which results in that the charge states of other battery packs connected in series cannot be fully utilized.
2. Parallel mismatch; referring to fig. 2, the capacities of the three parallel battery packs in fig. 2 are 8%, 13% and 20%, respectively, and according to the basic characteristics of the parallel circuit, the available charge states of the battery packs on the parallel link can only reach the charge state of the weakest battery pack, so that the available capacity of the battery packs on the whole link is only 8%, which results in that the charge states of other parallel battery packs cannot be fully utilized.
3. When the battery packs are applied in series, the difference between the new battery pack and the old battery pack can cause that the new battery pack cannot be fully utilized; when the battery pack is applied in parallel, the difference of internal resistances of the new battery pack and the old battery pack can cause inter-cluster circulation, so that the temperature of the battery pack is increased, the aging of the new battery pack is accelerated, the heat dissipation energy consumption of the system is high, and the charge and discharge efficiency is reduced.
In order to solve the above-mentioned drawbacks, the energy storage battery introduces the following switching method to improve the utilization ratio of the battery pack:
(1) referring to fig. 3, a single stage DC/AC conversion is configured without taking into consideration the case of a short plate of the battery pack, and the battery pack is not controlled. The method has low cost, can solve the parallel adaptation problem, but still cannot fully utilize the battery pack, and has a narrow battery pack voltage range.
(2) Referring to fig. 4, considering the short plate problem of the battery pack, the 0/1 bypass switching control is performed on the battery pack, and a one-stage DC/DC converter is added in addition to the one-stage DC/AC converter. When a single battery pack reaches a limit point of charge and discharge in the charge and discharge process, the 0/1 bypass switching control can cut the battery pack which reaches the limit point of charge and discharge from the battery pack string independently, but the voltage of the whole battery pack string can generate step jump, and after a plurality of battery packs are continuously cut, the voltage of the battery pack string can be reduced to a state that the DC/AC inversion normal work cannot be supported, so that the voltage of the battery pack string needs to be regulated in a boosting way through a DC/DC converter so as to meet the DC/AC work requirement. However, the two-stage conversion has low efficiency and high cost, and the 0/1 bypass switching control has great impact on the stability of the system, and meanwhile, the energy of each battery pack of the whole string cannot be fully utilized.
Therefore, the applicant provides a bypass balance control scheme of an energy storage battery, and a bypass circuit is additionally provided, when a certain battery pack and other battery packs are most unbalanced in the charging and discharging process, the bypass circuit is started to dynamically adjust the charging and discharging currents of the battery packs, so that all the battery packs in the whole battery pack string are balanced to reach the limit point of charging and discharging, and the energy of each battery pack in the whole battery pack string is ensured to be fully utilized. On the basis of the above solution, however, the applicant also needs to consider how to design the operation mode of the bypass circuit so that it can adapt to different equalization requirements.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a bypass balance control method and a bypass balance control system applied to an energy storage battery, which can adapt to different balance requirements.
In a first aspect, a bypass equalization control method applied to an energy storage battery includes:
collecting current, voltage and charge state of a battery pack to be balanced in a battery pack string in the charge-discharge process of the battery pack string;
acquiring a control strategy;
generating a control instruction according to the current, the voltage, the state of charge and the control strategy of the battery pack to be balanced;
and controlling the bypass circuit to act according to the control instruction so that one part of charge and discharge current flows through the battery pack to be balanced, wherein the battery pack to be balanced is in a constant current mode, a constant voltage mode, a constant power mode or a constant resistance mode, and the other part of charge and discharge current flows through the bypass circuit.
Further, the control strategy is a constant current strategy;
causing a part of the charge-discharge current to flow through the battery pack to be equalized specifically includes:
and controlling the current flowing into or out of the battery pack to be balanced to be constant and equal to a current threshold value so that the battery pack to be balanced is in a constant current mode.
Further, the control strategy is a constant pressure strategy;
causing a part of the charge-discharge current to flow through the battery pack to be equalized specifically includes:
and controlling a part of charge-discharge current to flow through the battery to be balanced so that the voltage of the battery pack to be balanced is constant and equal to the voltage threshold value, and the battery pack to be balanced is in a constant voltage mode.
Further, the control strategy is a constant power strategy;
causing a part of the charge-discharge current to flow through the battery pack to be equalized specifically includes:
and controlling a part of charge-discharge current to flow through the battery to be balanced so that the power flowing into or out of the battery pack to be balanced is constant and equal to a power threshold value, and the battery pack to be balanced is in a constant power mode.
Further, the control strategy is a constant resistance strategy;
causing a part of the charge-discharge current to flow through the battery pack to be equalized specifically includes:
and controlling a part of charge and discharge current to flow through the battery to be balanced so that the impedance presented by the battery pack to be balanced is constant and equal to the impedance threshold value, and the battery pack to be balanced is in a constant-impedance mode.
In a second aspect, a bypass equalization control system for an energy storage battery, comprising:
the acquisition unit: the method comprises the steps of collecting current, voltage and charge state of a battery pack to be balanced in a battery string in the charge-discharge process of the battery string;
configuration unit: for obtaining a control strategy;
and a control unit: the control instruction is generated according to the current, the voltage, the state of charge and the control strategy of the battery pack to be balanced;
an execution unit: and the bypass circuit is controlled to act according to the control instruction, so that one part of charge and discharge current flows through the battery pack to be balanced, the battery pack to be balanced is in a constant current mode, a constant voltage mode, a constant power mode or a constant resistance mode, and the other part of charge and discharge current flows through the bypass circuit.
Further, the control strategy is a constant current strategy;
the execution unit is specifically configured to:
and controlling the current flowing into or out of the battery pack to be balanced to be constant and equal to a current threshold value so that the battery pack to be balanced is in a constant current mode.
Further, the control strategy is a constant pressure strategy;
the execution unit is specifically configured to:
and controlling a part of charge-discharge current to flow through the battery to be balanced so that the voltage of the battery pack to be balanced is constant and equal to the voltage threshold value, and the battery pack to be balanced is in a constant voltage mode.
Further, the control strategy is a constant power strategy;
the execution unit is specifically configured to:
and controlling a part of charge-discharge current to flow through the battery to be balanced so that the power flowing into or out of the battery pack to be balanced is constant and equal to a power threshold value, and the battery pack to be balanced is in a constant power mode.
Further, the control strategy is a constant resistance strategy;
the execution unit is specifically configured to:
and controlling a part of charge and discharge current to flow through the battery to be balanced so that the impedance presented by the battery pack to be balanced is constant and equal to the impedance threshold value, and the battery pack to be balanced is in a constant-impedance mode.
According to the technical scheme, the bypass equalization control method and the bypass equalization control system applied to the energy storage battery control the battery pack to be equalized in different working modes, and can adapt to different equalization requirements of the system.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. Like elements or portions are generally identified by like reference numerals throughout the several figures. In the drawings, elements or portions thereof are not necessarily drawn to scale.
Fig. 1 is a schematic diagram of a series mismatch present in a battery series link in the background art.
Fig. 2 is a schematic diagram of the parallel mismatch existing in the parallel links of the battery in the background art.
Fig. 3 is a schematic diagram of an energy storage system according to the background art.
Fig. 4 is a schematic diagram of another energy storage system according to the background art.
Fig. 5 is a schematic diagram of a bypass equalization control system according to an embodiment.
Fig. 6 is a flowchart of a bypass equalization control method according to an embodiment.
Fig. 7 is a block diagram of a bypass equalization control system according to an embodiment.
Detailed Description
Embodiments of the technical scheme of the present invention will be described in detail below with reference to the accompanying drawings. The following examples are only for more clearly illustrating the technical aspects of the present invention, and thus are merely examples, and are not intended to limit the scope of the present invention. It is noted that unless otherwise indicated, technical or scientific terms used herein should be given the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.
It should be understood that the terms "comprises" and "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
It is also to be understood that the terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in this specification and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.
As used in this specification and the appended claims, the term "if" may be interpreted as "when..once" or "in response to a determination" or "in response to detection" depending on the context. Similarly, the phrase "if a determination" or "if a [ described condition or event ] is detected" may be interpreted in the context of meaning "upon determination" or "in response to determination" or "upon detection of a [ described condition or event ]" or "in response to detection of a [ described condition or event ]".
Fig. 5 is a schematic diagram of a bypass balancing control scheme of an energy storage battery provided by the applicant, and a new bypass circuit (indicated by a bypass balancing controller in fig. 5) is added, and when a certain battery pack and other battery packs are most unbalanced in a charging and discharging process, the bypass circuit is started to dynamically adjust charging and discharging currents of the battery packs, so that all battery packs in the whole battery string can reach a limit point of charging and discharging in a balancing manner, and energy of each battery pack in the whole battery string is guaranteed to be fully utilized.
Examples:
a bypass equalization control method applied to an energy storage battery, see fig. 6, includes:
s1: collecting current, voltage and charge state of a battery pack to be balanced in a battery pack string in the charge-discharge process of the battery pack string;
s2: acquiring a control strategy;
s3: generating a control instruction according to the current, the voltage, the state of charge and the control strategy of the battery pack to be balanced;
s4: and controlling the bypass circuit to act according to the control instruction so that one part of charge and discharge current flows through the battery pack to be balanced, wherein the battery pack to be balanced is in a constant current mode, a constant voltage mode, a constant power mode or a constant resistance mode, and the other part of charge and discharge current flows through the bypass circuit.
In this embodiment, when the battery string is in a discharge state, the battery pack with the lowest state of charge in the battery string is the battery pack to be equalized. When the battery string is in a charging state, the battery pack with the highest charging state in the battery string is the battery pack to be balanced. For the battery pack to be balanced with the lowest state of charge in the discharging process, the bypass circuit needs to be controlled to output a part of discharging current, and the discharging current of the battery pack to be balanced is reduced, so that after a period of time is adjusted, the state of charge of the battery pack to be balanced is slowly adjusted to be not the lowest. For the battery pack to be balanced with the highest charge state in the charging process, a part of charging current needs to be controlled to flow into a bypass circuit, so that the charging current of the battery pack to be balanced is reduced, and the charge state of the battery pack to be balanced is slowly adjusted to be not the highest after a period of adjustment, so that all the battery packs in the whole battery pack string reach the limit point of charging and discharging at the same time, and the energy of each battery pack is fully utilized. The control policy may be self-formulated by the bypass circuit, self-formulated by a manager or received by an external device uploading policy, etc.
In this embodiment, the method first collects the current, voltage and state of charge of the battery pack to be balanced in the charging and discharging process, where the state of charge of the battery may be an SOC value of the battery. When the bypass balance control method is applied to an energy storage system, a control strategy is used for reflecting balance requirements of the system, for example, the control strategy comprises constant-current discharge, constant-power discharge, constant-voltage discharge, constant-resistance discharge, constant-current charge, constant-power charge, constant-voltage charge, constant-resistance charge and the like. The equilibrium requirements of the system include that the battery operates in a constant current, constant voltage, constant power or constant impedance state.
In this embodiment, the method generates a control command according to the current, voltage, state of charge and control strategy of the battery pack to be equalized. For example, when the bypass circuit includes a first switching assembly connected to the battery pack to be equalized and a second switching assembly connected to the next-stage battery pack. When the first switch component and the second switch component are both closed, all total charge and discharge currents charge and discharge the battery pack to be balanced through the body diode of the first switch component, and the current flowing through the second switch component is zero. When the first switch component and the second switch component are started, part of current in the total charge and discharge current flows through the first switch component to charge and discharge the battery pack to be balanced, and the other part of current flows through the second switch component to the next battery pack. At this time, the control instruction may be a PWM signal, and the method may generate a first PWM signal and a second PWM signal according to the current, the voltage, and the state of charge of the battery pack to be equalized, where the first PWM signal controls on/off of the first switch assembly, and the second PWM signal controls on/off of the second switch assembly. The PWM signal can adjust the on-off time of the switching tube by adjusting the duty ratio of the PWM signal so as to adjust the charge and discharge current flowing through the battery pack to be balanced.
In this embodiment, the method may control the battery packs to be balanced to be in different working modes according to a control policy of the system. For example, during discharging, the battery pack to be balanced is controlled to be in constant-current discharging, constant-voltage discharging, constant-power discharging or constant-resistance discharging according to a control strategy. And during charging, the battery pack to be balanced is controlled to be in constant-current charging, constant-voltage charging, constant-power charging or constant-resistance charging according to a control strategy. Therefore, the method controls the battery pack to be balanced to be in different working modes, and can adapt to different balancing demands of the system.
Further, in some embodiments, the control strategy is a constant current strategy;
causing a part of the charge-discharge current to flow through the battery pack to be equalized specifically includes:
and controlling the current flowing into or out of the battery pack to be balanced to be constant and equal to a current threshold value so that the battery pack to be balanced is in a constant current mode.
In this embodiment, the method controls the constant current flowing into or out of the battery pack to be balanced in order to adapt to the constant current strategy of the system. For example, when discharging, the current flowing from the battery pack to be balanced is controlled to be constant, and the other part of current flows from the bypass circuit to the next-stage battery pack, so that the balancing requirement of constant-current discharging of the system is adapted. When in charging, the current flowing into the battery pack to be balanced is controlled to be constant, and the other part of current flows into the next-stage battery pack from the bypass circuit, so that the balancing requirement of constant-current charging of the system is met.
In this embodiment, the current threshold may be initialized before the method is run or may be adjusted after the run. The current threshold may be a fixed current value, a ratio or range of ratios to total charge-discharge current, a ratio or range of ratios to single battery pack current, or the like. For example, when the battery string is charged, the SOC of the battery pack a in the battery string is read to be 80%, the SOC of the other battery packs is read to be 60%, and the battery pack a is the battery to be equalized. When the system adopts a constant current strategy, the ratio of the current of the battery pack A to the current of the bypass circuit can be set to be 1:1, namely the current threshold value is set to be 1:1. The current flowing into battery pack a is thus half the total charge current, so that in an ideal case battery pack a and the other battery packs would charge to 100% SOC at the same time. For example, the battery packs are all in a charge state of 100Ah, the battery pack ASOC is 80Ah, the other battery packs are in an SOC of 60Ah, the system is charged with 20A constant current, then the battery pack A can reach 100% SOC at 10A for 2 hours in a constant current mode, and the other battery packs can reach 100% SOC at 20A for 2 hours.
Further, in some embodiments, the control strategy is a constant pressure strategy;
causing a part of the charge-discharge current to flow through the battery pack to be equalized specifically includes:
and controlling a part of charge-discharge current to flow through the battery to be balanced so that the voltage of the battery pack to be balanced is constant and equal to the voltage threshold value, and the battery pack to be balanced is in a constant voltage mode.
In this embodiment, in order to adapt to the constant voltage strategy of the system, the method controls the voltage of the battery pack to be balanced in the charging and discharging process to be constant. For example, during discharging, the port voltage of the battery pack to be balanced, which is externally embodied, is controlled to be constant, so that the battery pack to be balanced can be discharged with the maximum capacity under the condition of constant voltage, and the balancing requirement of constant voltage discharging of the system is adapted. During charging, the port voltage of the battery pack to be balanced, which is externally embodied, is controlled to be constant, so that the battery pack to be balanced can be charged with the maximum capacity under the condition of constant voltage, and the balancing requirement of constant voltage charging of the system is adapted.
In this embodiment, the voltage threshold may be initialized before the method is run or may be adjusted after the run. The voltage threshold may be a fixed voltage value, a ratio or range of ratios to the total charge-discharge voltage, a ratio or range of ratios to the single battery pack voltage, or the like. For example, when the battery string is charged, the SOC of the battery pack a in the battery string is read to be 80%, the SOC of the other battery packs is read to be 70%, and the battery pack a is the battery to be equalized. When the system adopts a constant voltage strategy, the voltage threshold is set to be a specified voltage value. Therefore, after the battery pack A reaches the specified voltage value, the port of the battery pack A is subjected to constant voltage, the current flowing into the battery pack A is reduced, and the charging is stopped after other battery packs reach the specified voltage value, so that the voltages of all the battery packs can be balanced.
Further, in some embodiments, the control strategy is a constant power strategy;
causing a part of the charge-discharge current to flow through the battery pack to be equalized specifically includes:
and controlling a part of charge-discharge current to flow through the battery to be balanced so that the power flowing into or out of the battery pack to be balanced is constant and equal to a power threshold value, and the battery pack to be balanced is in a constant power mode.
In this embodiment, in order to adapt to the constant power policy of the system, the method controls the power flowing in or out to be constant during the charge and discharge of the battery pack to be balanced. For example, when discharging, the output power of the battery pack to be balanced is controlled to be constant, and the balancing requirement of the system when discharging with constant power is adapted. And during charging, controlling the constant power of the battery pack to be balanced, and adapting to the balance requirement of the system during constant power charging.
In this embodiment, the power threshold may be initialized before the method is run, or may be adjusted after the run. The power threshold may be a fixed power value, a ratio or range of ratios to total charge and discharge power, a ratio or range of ratios to single battery pack power, and so forth. For example, assume that the battery string includes 10 battery packs connected in series, and the total charging power is constant at 100kw. When the battery string is charged, if the SOCs of all the battery packs are equalized, the bypass circuit is not operated, and the charge power per battery pack is 100 kw/10=10 kw. If the SOC of the battery pack a in the battery string is relatively high, the battery pack a is a battery to be balanced, and in this case, in order to keep balancing of all the battery packs, the charging power required by the battery pack a is reduced. Assuming that the power threshold of the battery to be equalized is set to be half of the original charging power, at this time, the charging power of the battery pack a is reduced to 5kw, then the remaining charging power is 95kw, and is divided equally into the remaining 9 battery packs, then the charging power of each remaining battery pack is 95 kw/9=10.55 kw. In this way, the charging power of the battery pack A is reduced, and the charging power of other batteries is increased, so that the charge states of all the battery packs can reach 100% SOC at the same time.
Further, in some embodiments, the control strategy is a constant resistance strategy;
causing a part of the charge-discharge current to flow through the battery pack to be equalized specifically includes:
and controlling a part of charge and discharge current to flow through the battery to be balanced so that the impedance presented by the battery pack to be balanced is constant and equal to the impedance threshold value, and the battery pack to be balanced is in a constant-impedance mode.
In this embodiment, in order to adapt to the constant resistance policy of the system, the method controls the impedance presented in the charging and discharging process of the battery pack to be balanced to be constant. For example, when discharging, the battery pack to be balanced is controlled to present set impedance, and the proportional relation between the port voltage and the current of the battery pack to be balanced is maintained, so as to adapt to the balancing requirement of constant-resistance discharging of the system. During charging, the battery pack to be balanced is controlled to present set impedance, and the proportional relation between the port voltage and the current of the battery pack to be balanced is maintained, so that the balancing requirement of constant-resistance charging of the system is met.
In this embodiment, the impedance threshold may be initialized before the method is run, or may be adjusted after the run. The impedance threshold may be a fixed impedance value, a ratio or range of ratios to total charge-discharge impedance, a ratio or range of ratios to single battery pack impedance, or the like.
A bypass equalization control system for an energy storage battery, see fig. 7, comprising:
acquisition unit 1: the method comprises the steps of collecting current, voltage and charge state of a battery pack to be balanced in a battery string in the charge-discharge process of the battery string;
configuration unit 2: for obtaining a control strategy;
control unit 3: the control instruction is generated according to the current, the voltage, the state of charge and the control strategy of the battery pack to be balanced;
execution unit 4: and the bypass circuit is controlled to act according to the control instruction, so that one part of charge and discharge current flows through the battery pack to be balanced, the battery pack to be balanced is in a constant current mode, a constant voltage mode, a constant power mode or a constant resistance mode, and the other part of charge and discharge current flows through the bypass circuit.
Further, in some embodiments, the control strategy is a constant current strategy;
the execution unit 4 is specifically configured to:
and controlling the current flowing into or out of the battery pack to be balanced to be constant and equal to a current threshold value so that the battery pack to be balanced is in a constant current mode.
Further, in some embodiments, the control strategy is a constant pressure strategy;
the execution unit 4 is specifically configured to:
and controlling a part of charge-discharge current to flow through the battery to be balanced so that the voltage of the battery pack to be balanced is constant and equal to the voltage threshold value, and the battery pack to be balanced is in a constant voltage mode.
Further, in some embodiments, the control strategy is a constant power strategy;
the execution unit 4 is specifically configured to:
and controlling a part of charge-discharge current to flow through the battery to be balanced so that the power flowing into or out of the battery pack to be balanced is constant and equal to a power threshold value, and the battery pack to be balanced is in a constant power mode.
Further, in some embodiments, the control strategy is a constant resistance strategy;
the execution unit 4 is specifically configured to:
and controlling a part of charge and discharge current to flow through the battery to be balanced so that the impedance presented by the battery pack to be balanced is constant and equal to the impedance threshold value, and the battery pack to be balanced is in a constant-impedance mode.
For a brief description of the system provided by the embodiments of the present invention, reference may be made to the corresponding content in the foregoing embodiments where the description of the embodiments is not mentioned.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the invention, and are intended to be included within the scope of the appended claims and description.

Claims (10)

1. A bypass equalization control method applied to an energy storage battery, comprising:
collecting current, voltage and charge state of a battery pack to be balanced in a battery pack string in the charge-discharge process of the battery pack string;
acquiring a control strategy;
generating a control instruction according to the current, the voltage, the state of charge and the control strategy of the battery pack to be balanced;
and controlling the action of a bypass circuit according to the control instruction so that one part of charge and discharge current flows through the battery pack to be balanced, wherein the battery pack to be balanced is in a constant current mode, a constant voltage mode, a constant power mode or a constant resistance mode, and the other part of charge and discharge current flows through the bypass circuit.
2. The method for bypass equalization control applied to an energy storage cell as claimed in claim 1, wherein,
the control strategy is a constant current strategy;
the making a part of charge-discharge current flow through the battery pack to be equalized specifically includes:
and controlling the current flowing into or out of the battery pack to be balanced to be constant and equal to a current threshold value so that the battery pack to be balanced is in the constant current mode.
3. The method for bypass equalization control applied to an energy storage cell as claimed in claim 1, wherein,
the control strategy is a constant-pressure strategy;
the making a part of charge-discharge current flow through the battery pack to be equalized specifically includes:
and controlling a part of charge-discharge current to flow through the battery to be balanced so that the voltage of the battery pack to be balanced is constant and equal to a voltage threshold value, and the battery pack to be balanced is in the constant voltage mode.
4. The method for bypass equalization control applied to an energy storage cell as claimed in claim 1, wherein,
the control strategy is a constant power strategy;
the making a part of charge-discharge current flow through the battery pack to be equalized specifically includes:
and controlling a part of charge and discharge current to flow through the battery to be balanced so that the power flowing into or out of the battery pack to be balanced is constant and equal to a power threshold value, and the battery pack to be balanced is in the constant power mode.
5. The method for bypass equalization control applied to an energy storage cell as claimed in claim 1, wherein,
the control strategy is a constant resistance strategy;
the making a part of charge-discharge current flow through the battery pack to be equalized specifically includes:
and controlling a part of charge and discharge current to flow through the battery to be balanced so that the impedance presented by the battery pack to be balanced is constant and equal to an impedance threshold value, and the battery pack to be balanced is in the constant-impedance mode.
6. A bypass equalization control system for an energy storage battery, comprising:
the acquisition unit: the method comprises the steps of collecting current, voltage and charge state of a battery pack to be balanced in a battery pack string in the charge-discharge process of the battery pack string;
configuration unit: for obtaining a control strategy;
and a control unit: the control command is generated according to the current, the voltage, the charge state and the control strategy of the battery pack to be balanced;
an execution unit: and the bypass circuit is controlled to act according to the control instruction, so that one part of charge and discharge current flows through the battery pack to be balanced, the battery pack to be balanced is in a constant current mode, a constant voltage mode, a constant power mode or a constant resistance mode, and the other part of charge and discharge current flows through the bypass circuit.
7. The bypass equalization control system for an energy storage battery of claim 6, wherein,
the control strategy is a constant current strategy;
the execution unit is specifically configured to:
and controlling the current flowing into or out of the battery pack to be balanced to be constant and equal to a current threshold value so that the battery pack to be balanced is in the constant current mode.
8. The bypass equalization control system for an energy storage battery of claim 6, wherein,
the control strategy is a constant-pressure strategy;
the execution unit is specifically configured to:
and controlling a part of charge-discharge current to flow through the battery to be balanced so that the voltage of the battery pack to be balanced is constant and equal to a voltage threshold value, and the battery pack to be balanced is in the constant voltage mode.
9. The bypass equalization control system for an energy storage battery of claim 6, wherein,
the control strategy is a constant power strategy;
the execution unit is specifically configured to:
and controlling a part of charge and discharge current to flow through the battery to be balanced so that the power flowing into or out of the battery pack to be balanced is constant and equal to a power threshold value, and the battery pack to be balanced is in the constant power mode.
10. The bypass equalization control system for an energy storage battery of claim 6, wherein,
the control strategy is a constant resistance strategy;
the execution unit is specifically configured to:
and controlling a part of charge and discharge current to flow through the battery to be balanced so that the impedance presented by the battery pack to be balanced is constant and equal to an impedance threshold value, and the battery pack to be balanced is in the constant-impedance mode.
CN202310334715.XA 2023-03-27 2023-03-27 Bypass balance control method and system applied to energy storage battery Pending CN116316998A (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070080662A1 (en) * 2005-10-11 2007-04-12 Deping Wu Universal battery module and controller therefor
CN101123359A (en) * 2006-08-10 2008-02-13 东华能源科技股份有限公司 A charging circuit without loss balance charging multiple serial batteries
CN101958566A (en) * 2010-10-12 2011-01-26 陈林 Battery pack charging device for equalizing charging
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