WO2017139967A1 - 电池包均衡方法、电池管理系统及电池系统 - Google Patents

电池包均衡方法、电池管理系统及电池系统 Download PDF

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Publication number
WO2017139967A1
WO2017139967A1 PCT/CN2016/074116 CN2016074116W WO2017139967A1 WO 2017139967 A1 WO2017139967 A1 WO 2017139967A1 CN 2016074116 W CN2016074116 W CN 2016074116W WO 2017139967 A1 WO2017139967 A1 WO 2017139967A1
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Prior art keywords
battery
iron phosphate
battery pack
lithium iron
voltage data
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English (en)
French (fr)
Inventor
陈玲
杨元金
周伟
邓兆轩
蔡毅
种晋
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Contemporary Amperex Technology Co Ltd
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Contemporary Amperex Technology Co Ltd
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Priority to CN201680081297.6A priority Critical patent/CN108780927B/zh
Priority to PCT/CN2016/074116 priority patent/WO2017139967A1/zh
Publication of WO2017139967A1 publication Critical patent/WO2017139967A1/zh
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    • 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
    • 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

Definitions

  • the present invention relates to the field of battery technologies, and in particular, to a battery pack equalization method, a battery management system, and a battery system.
  • LiFePO 4 Battery Pack has a typical charging and discharging platform. This excellent electrical performance, high cycle life and high safety make this product widely used in electric vehicles and energy storage.
  • the lithium iron phosphate battery system consists of a lithium iron phosphate battery pack and a battery management system.
  • the lithium iron phosphate battery pack consists of a large number of battery cells connected in series or in parallel or mixed.
  • the battery unit is not identical due to variations in raw materials and manufacturing processes, so the state of charge (SoC) between the cells is not the same.
  • SoC state of charge
  • the present invention provides a battery pack equalization method, a battery management system, and a battery system, which improves the consistency of the state of charge between the battery cells in the lithium iron phosphate battery pack, and prolongs the use of the lithium iron phosphate battery pack. life.
  • An aspect of an embodiment of the present invention provides a battery pack equalization method, including:
  • the lithium iron phosphate battery pack A battery unit having a difference between the voltage data and the minimum voltage value greater than or equal to the voltage threshold performs discharge.
  • the specified condition comprising: voltage data of the discharged battery cells in the iron phosphate battery pack being consistent with the minimum voltage value.
  • the sleep mode includes the lithium iron phosphate battery pack having no input energy or output energy.
  • each battery unit comprising one battery cell, or each battery cell comprising at least two battery cells in parallel.
  • each battery cell in the lithium iron phosphate battery pack comprises lithium iron phosphate having a solid content of greater than or equal to 90% in the cathode active material. Lithium ion battery cell.
  • An aspect of an embodiment of the present invention provides a battery management system, including:
  • a detecting module for detecting voltage data of each battery unit in the lithium iron phosphate battery pack
  • a power estimation module configured to obtain the lithium iron phosphate battery according to voltage data of each battery unit The state of charge of the package
  • An equalization module configured to obtain a minimum voltage value in the voltage data; and, determining whether the state of charge is located at 10% to 40%, and respectively comparing voltage data of each battery unit in the lithium iron phosphate battery pack Comparing the difference between the minimum voltage values with a preset voltage threshold; and, if it is determined that the state of charge is between 10% and 40%, and there is a difference between the voltage data and the minimum voltage value
  • the battery unit having a value greater than or equal to the voltage threshold performs discharging on a battery unit in which a difference between voltage data and the minimum voltage value in the lithium iron phosphate battery pack is greater than or equal to the voltage threshold.
  • equalization module is further configured to:
  • the specified condition comprising: voltage data of the discharged battery cells in the iron phosphate battery pack being consistent with the minimum voltage value.
  • the detecting module is specifically configured to: detect, in a sleep mode, voltage data of each battery unit in a lithium iron phosphate battery pack;
  • the sleep mode includes the lithium iron phosphate battery pack having no input energy or output energy.
  • each battery unit comprising one battery cell, or each battery cell comprising at least two battery cells in parallel.
  • a battery system including a lithium iron phosphate battery pack and the above battery management system is provided.
  • the lithium iron phosphate battery pack includes a lithium ion battery bill having a solid content of lithium iron phosphate in the cathode active material of greater than or equal to 90%. body.
  • whether the equalization start is satisfied is determined according to the difference between the state of charge of the lithium iron phosphate battery pack and the voltage data of each battery cell in the lithium iron phosphate battery pack and the minimum voltage value.
  • the equalization start condition that is, the state of charge is at the low end (ie, the state of charge is at 10% to 40%), and there is a battery unit whose difference between the voltage data and the minimum voltage value is greater than or equal to the voltage threshold, Discharging the battery unit that satisfies the equalization starting condition, so that the voltage of the battery unit with higher voltage data in the lithium iron phosphate battery pack tends to be consistent with the minimum voltage value, thereby reducing the imbalance of charge between the battery units.
  • the equalization efficiency of the lithium iron phosphate battery pack can be effectively improved by the low-end equalization.
  • Embodiment 1 is a schematic flow chart of Embodiment 1 of a method for equalizing a battery pack according to an embodiment of the present invention
  • Embodiment 2 is a schematic flow chart of Embodiment 2 of a battery pack equalization method according to an embodiment of the present invention
  • FIG. 3 is a graph showing a relationship between a state of charge and a voltage of a lithium iron phosphate battery pack according to an embodiment of the present invention
  • Embodiment 4 is a schematic flow chart of Embodiment 3 of a battery pack equalization method according to an embodiment of the present invention
  • FIG. 5 is a functional block diagram of Embodiment 1 of a battery management system according to an embodiment of the present invention.
  • Embodiment 2 of a battery management system according to an embodiment of the present invention
  • FIG. 7 is a functional block diagram of a battery system according to an embodiment of the present invention.
  • the word “if” as used herein may be interpreted as “when” or “when” or “in response to a determination” or “in response to Detection”.
  • the phrase “if determined” or “if detected (conditions or events stated)” may be interpreted as “when determined” or “in response to determination” or “when detected (stated condition or event) “Time” or “in response to a test (condition or event stated)”.
  • Lithium iron phosphate battery pack has a typical charging and discharging platform. This excellent electrical performance, high cycle life and high safety make this product widely used in electric vehicles and energy storage.
  • the lithium iron phosphate battery system consists of a lithium iron phosphate battery pack and a battery management system.
  • the lithium iron phosphate battery pack consists of a large number of battery cells connected in series or in parallel or mixed. Due to variations in raw materials and manufacturing processes, the state of charge between battery cells is not exactly the same.
  • the charging imbalance between the battery cells gradually increases, directly affecting the power capability of the lithium iron phosphate battery system. And the use of available energy, reducing the service life of lithium iron phosphate battery pack. Therefore, it is very necessary to balance the lithium iron phosphate battery pack.
  • the high-end equalization method There are two main methods for equalizing lithium iron phosphate battery packs, one is the high-end equalization method, and the other is the low-end equalization method.
  • the low-end equalization refers to starting the equalization when the state of charge is between 10% and 40% and the differential pressure meets the equilibrium start condition.
  • the high-end equalization refers to the state of charge at 90% to 100% and the pressure difference. Start balancing under the equilibrium start condition. Before the equalization method was selected, different experiments were performed on several samples. As shown in Table 1, the high-end equilibrium used three lithium iron phosphate battery pack samples for experimentation. Before the high-end equalization, the charge imbalance was 17.1.
  • the charging imbalance ⁇ SoC can be calculated in two ways, one is the difference between the average value of the state of charge of each battery cell in the lithium iron phosphate battery pack and the minimum value of the state of charge.
  • the other is the difference between the maximum value of the state of charge of each battery cell in the lithium iron phosphate battery pack and the minimum value of the state of charge.
  • the degree of charge imbalance mentioned in this embodiment is the difference between the average value of the state of charge of each battery cell in the lithium iron phosphate battery pack and the minimum value of the state of charge.
  • Five samples were used to equalize the lithium iron phosphate battery pack using a low-end equalization method, and two of the samples, sample 2 and sample 3, were identical to those used for high-end equalization. It can be seen from Table 1 that the five samples pass the low-end equilibrium mode, and the charge imbalance is reduced from 27.6%, 22.9%, 6.1%, 5.4%, 4.8% to 2.0%, 1.6%, and 1.8%, respectively.
  • the differential pressure is reduced from 16mV, 62mV, 26mV, 24mV, 18mV to 8mV, 8mV, 6mV, 4mV, 4mV. It can be seen that the low-end equalization is more obvious than the high-end equalization, and the improvement of the charging imbalance between the battery cells in the lithium iron phosphate battery pack is more obvious. Therefore, the effective equalization methods involved in the following embodiments are all low-end equalization methods.
  • the embodiment of the present invention provides a battery pack equalization method.
  • FIG. 1 it is a schematic flowchart of Embodiment 1 of a battery pack equalization method according to an embodiment of the present invention. As shown in the figure, the method includes the following steps:
  • the lithium iron phosphate battery is The battery unit in which the difference between the voltage data in the packet and the minimum voltage value is greater than or equal to the voltage threshold performs discharge.
  • FIG. 2 is a schematic flowchart of Embodiment 2 of a battery pack balancing method according to an embodiment of the present invention.
  • This embodiment is a specific implementation method of Embodiment 1. As shown, the method includes the following steps:
  • the voltage data of each battery unit in the lithium iron phosphate battery pack can be detected in the sleep mode.
  • the sleep mode refers to that the lithium iron phosphate battery pack has no input energy or output energy.
  • a lithium iron phosphate battery pack is generally composed of a plurality of battery cells connected in series or in parallel or mixed.
  • each battery unit may include one battery unit, or each battery unit may also include at least two battery cells connected in parallel, that is, each battery unit may be composed of a plurality of battery cells connected in parallel. of.
  • each of the battery cells of the lithium iron phosphate battery pack comprises a lithium ion battery cell having a solid content of lithium iron phosphate in the cathode active material of greater than or equal to 90%.
  • the discharge process may be completed intermittently before the voltage data of the battery unit discharged in the lithium iron phosphate battery pack reaches a preset condition, that is, after the discharge is continued for a preset period of time 1, the iron phosphate battery pack After entering the sleep mode, the duration of maintaining the sleep mode reaches the preset duration of 2, and then wakes up the battery management system and re-executes the equalization process of S201 to S207.
  • the preset duration 1 and the preset duration 2 can be comprehensively considered and set according to the hardware characteristics of the execution body of the equalization operation and the equalization efficiency, for example, 5 minutes, 10 minutes, 1 hour, or 3 hours, etc., can be preset.
  • the duration 1 and the preset duration 2 may be the same or different.
  • the state of charge data of each battery unit in the lithium iron phosphate battery pack is detected, and the state of charge indicates the remaining capacity of the battery after being used for a period of time or for a long period of time.
  • the ratio of the capacity of the fully charged state can be expressed in percentage.
  • the voltage data of each battery unit in the lithium iron phosphate battery pack can be detected and recorded.
  • the voltage data of each battery unit can be sequentially recorded as U 1 , U 2 , ..., U. N , where N represents the number of battery cells in the lithium iron phosphate battery pack.
  • the iron phosphate after detecting the voltage data of each battery unit in the lithium iron phosphate battery pack, the iron phosphate can be quickly obtained according to the voltage data of each battery unit in the lithium iron phosphate battery pack. The state of charge of the lithium battery pack.
  • the state of charge refers to the ratio of the remaining amount of electricity to the amount of charge after the use of the lithium iron phosphate battery pack for a period of time or after being used for a long period of time, and can be expressed as a percentage.
  • the voltage data of each battery cell can be sorted according to the order of largest to small to obtain the minimum voltage value therein.
  • the voltage data of each battery cell may be sorted according to the order from small to large to obtain the minimum voltage value therein.
  • S203 determining whether the state of charge is located at 10% to 40%, and respectively comparing a difference between voltage data of each battery cell in the lithium iron phosphate battery pack and the minimum voltage value with a preset voltage threshold. Compare. If it is determined that the state of charge is between 10% and 40%, and there is a battery cell whose difference between the voltage data and the minimum voltage value is greater than or equal to the voltage threshold, S204 is performed; otherwise, S207 is performed.
  • the state of charge of the lithium iron phosphate battery pack it is further determined whether the state of charge is located at 10% to 40%, and simultaneously calculating the difference between the voltage data and the minimum voltage value of each battery unit.
  • the state of charge of the lithium iron phosphate battery pack is The lower end satisfies the equalization start condition, and indicates that the difference between the voltage data of the at least one battery cell and the minimum voltage value is large, and it is necessary to perform discharge on the battery cells in the lithium iron phosphate battery pack, so the process proceeds to S204. Otherwise, in other cases, S207 is performed.
  • the other situation includes: the state of charge is between 10% and 40%, but there is no battery unit whose difference between the voltage data and the minimum voltage value is greater than or equal to the voltage threshold.
  • the state of charge is not between 10% and 40%, but there is a battery cell whose difference between the voltage data and the minimum voltage value is greater than or equal to the voltage threshold.
  • the state of charge is not located at 10% to 40%, and the difference between the absence of the voltage data and the minimum voltage value is greater than or equal to the voltage threshold. Battery unit.
  • the difference between the voltage data of all the battery cells and the minimum voltage value is less than the voltage threshold, indicating that the difference between the voltage data and the minimum voltage value of the battery unit is small, and The charge balancing is performed, so S207 is executed.
  • the state of charge is not located at 10% to 40%, it indicates that the state of charge of the lithium iron phosphate battery pack is not at the low end, and may be in other charging intervals (such as 0 to 10% or 40% to 100%), Satisfying the equalization start condition, it is not necessary to perform discharge on the battery cells in the lithium iron phosphate battery pack, so S207 is performed.
  • the preset voltage threshold can be determined experimentally.
  • the preset voltage threshold can be equal to 8 mV.
  • FIG. 3 is a graph showing the relationship between the state of charge and the voltage of a lithium iron phosphate battery pack according to an embodiment of the present invention.
  • the relationship diagram can be performed on a battery unit in a lithium iron phosphate battery pack by a charging and discharging device. Tested.
  • the state of charge of the lithium iron phosphate battery pack is in the range of 10% to 40%, the state of charge has a strong correlation with the voltage. Therefore, in this interval, the voltage data of each battery cell is estimated and Correcting the state of charge can improve the accuracy of the calculated state of charge, and thus the equalization effect is good.
  • the state of charge state may be 15% to 35%.
  • the state of charge of the lithium iron phosphate battery pack is 90% to 100%, the interval is narrow, and the polarization characteristics of the lithium iron phosphate material and the difference between the battery cells in the lithium iron phosphate battery pack are required. Sex, the voltage drops to the platform area, the pressure difference is small, and it is not easy to trigger the equalization or trigger the equalization and the implementation effect is not good.
  • the state of charge is 40% to 90% in the platform area, there is almost no correlation between the state of charge and the voltage in this region, and it is impossible to trigger equalization or cause misbalance.
  • the end-equalization method is to equalize the battery cells in the lithium iron phosphate battery pack, and it is necessary to carry out the charging state of the lithium iron phosphate battery pack at 10% to 40%.
  • the state of charge of the lithium iron phosphate battery pack is 10% to 40%, and the difference between the voltage data and the minimum voltage value in the lithium iron phosphate battery pack is greater than or equal to
  • the battery unit of the voltage threshold is used, the battery unit in which the difference between the voltage data and the minimum voltage value in the lithium iron phosphate battery pack is greater than or equal to the voltage threshold is discharged, so that the discharge can be made to make the lithium iron phosphate battery pack
  • the voltage data is consistent with the voltage of the battery unit with the smallest voltage data in the lithium iron phosphate battery pack, thereby achieving the balance of the lithium iron phosphate battery pack and reducing the charging of the lithium iron phosphate battery pack. Unbalanced.
  • the phosphoric acid needs to be judged. Whether the voltage data of the battery cells discharged in the iron battery pack reaches the specified condition, and if it is determined that the voltage data of the battery cells discharged in the iron phosphate battery pack reaches the specified condition, S206 is performed. On the other hand, if it is judged that the voltage data of the battery cells discharged in the iron phosphate battery pack does not reach the specified condition, S201 is executed, that is, the operations of detecting, estimating, judging, and equalizing are performed again.
  • the specifying condition may include: voltage data of the discharged battery cells in the iron phosphate battery pack is consistent with the minimum voltage value.
  • the iron phosphate battery pack after performing discharge on the battery unit in which the difference between the voltage data and the minimum voltage value in the lithium iron phosphate battery pack is greater than or equal to the voltage threshold, it is necessary to determine the iron phosphate.
  • the pair is stopped.
  • the difference between the voltage data in the iron phosphate battery pack and the minimum voltage value is greater than or equal to the discharge of the battery unit of the voltage threshold, and after stopping the discharge of the battery unit, the lithium iron phosphate battery is realized. The charge balance of the package.
  • FIG. 4 is a schematic flowchart of Embodiment 3 of a battery pack balancing method according to an embodiment of the present invention.
  • This embodiment is another specific implementation method of Embodiment 1. As shown, the method includes the following steps:
  • the lithium iron phosphate battery pack is fully charged, and then discharged to a lithium iron phosphate battery pack with a state of charge of 20% to 25%.
  • Embodiments of the present invention further provide an apparatus embodiment for implementing the steps and methods in the foregoing method embodiments.
  • FIG. 5 is a functional block diagram of Embodiment 1 of a battery management system according to an embodiment of the present invention.
  • the battery management system includes:
  • the detecting module 51 is configured to detect voltage data of each battery unit in the lithium iron phosphate battery pack;
  • the power estimation module 52 is configured to acquire, according to voltage data of each battery unit, a state of charge of the lithium iron phosphate battery pack;
  • the equalization module 53 is configured to acquire a minimum voltage value in the voltage data; and determine the Whether the electrical state is between 10% and 40%, and respectively comparing the difference between the voltage data of each battery cell in the lithium iron phosphate battery pack and the minimum voltage value with a preset voltage threshold; and, if Determining that the state of charge is between 10% and 40%, and there is a battery cell whose difference between the voltage data and the minimum voltage value is greater than or equal to the voltage threshold, and the voltage in the lithium iron phosphate battery pack The battery unit whose difference between the data and the minimum voltage value is greater than or equal to the voltage threshold performs discharge.
  • the equalization module 53 is further configured to:
  • the specified condition includes: voltage data of the discharged battery cells in the iron phosphate battery pack is consistent with the minimum voltage value.
  • the detecting module 51 is configured to: detect, in a sleep mode, voltage data of each battery unit in the lithium iron phosphate battery pack; wherein the sleep mode includes that the lithium iron phosphate battery pack has no input energy or Output energy.
  • each battery unit comprises one battery cell, or each battery cell comprises at least two battery cells in parallel.
  • each of the battery cells in the lithium iron phosphate battery pack comprises a lithium ion battery cell having a solid content of lithium iron phosphate in the cathode active material of greater than or equal to 90%.
  • each unit in this embodiment can perform the method shown in FIG. 1, FIG. 2 or FIG. 4, and the parts not described in detail in this embodiment, reference may be made to the related description of FIG. 1, FIG. 2 or FIG.
  • FIG. 6 is a functional block diagram of Embodiment 2 of a battery management system according to an embodiment of the present invention.
  • the battery management system may further include: a charging module 54 for charging the lithium iron phosphate battery pack, and then discharging to a lithium iron phosphate battery pack with a state of charge of 10% to 40%.
  • FIG. 7 is a functional block diagram of a battery system according to an embodiment of the present invention.
  • the battery system includes a lithium iron phosphate battery pack 70 and the above battery management system 71.
  • the lithium iron phosphate battery pack includes lithium iron phosphate in the cathode active material.
  • whether the equalization start is satisfied is determined according to the difference between the state of charge of the lithium iron phosphate battery pack and the voltage data of each battery cell in the lithium iron phosphate battery pack and the minimum voltage value.
  • Condition if the equilibrium is satisfied, that is, the state of charge is at the low end (the state of charge is at 10% to 40%), and there is a battery cell whose difference between the voltage data and the minimum voltage value is greater than or equal to the voltage threshold, then The battery unit that satisfies the equalization starting condition is discharged, so that the voltage of the battery unit with higher voltage data in the lithium iron phosphate battery pack tends to be consistent with the minimum voltage value, thereby reducing the imbalance of the charging between the battery units.
  • the utility model can effectively realize the charge balance between the battery cells, thereby avoiding the problem of the power capability and the available energy of the lithium iron phosphate battery system caused by the large imbalance of the charge, and prolonging the lithium iron phosphate battery pack.
  • the service life Moreover, the equalization efficiency of the lithium iron phosphate battery pack can be effectively improved by the low-end equalization.
  • the technical solution provided by the embodiment of the present invention is better than the prior art in other charging states (the state of charge is 40% to 100%), and the charging balancing effect is better, and the error balancing can be prevented.
  • the balance effect is improved, the imbalance of the charge between the battery cells is minimized, and the inconsistency between the battery cells is improved, thereby prolonging the service life of the lithium iron phosphate battery pack.
  • the disclosed system, apparatus, and method may be implemented in other manners.
  • the device embodiments described above are merely illustrative.
  • the division of the unit is only a logical function division.
  • multiple units or components may be combined. Or it can be integrated into another system, or some features can be ignored or not executed.
  • the mutual coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interface, device or unit, and may be in an electrical, mechanical or other form.
  • the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of the embodiment.
  • each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.
  • the above integrated unit can be implemented in the form of hardware or in the form of hardware plus software functional units.
  • the above-described integrated unit implemented in the form of a software functional unit can be stored in a computer readable storage medium.
  • the above software functional unit is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) or a processor to perform the methods of the various embodiments of the present invention. Part of the steps.
  • the foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk, and the like, which can store program codes. .

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Abstract

一种电池包均衡方法、电池管理系统及电池系统。所述均衡方法包括：通过检测磷酸铁锂电池包中各电池单元的电压数据，并根据各电池单元的电压数据，获取磷酸铁锂电池包的荷电状态（S101），以及，获取电压数据中的最小电压值（S102）；从而，判断荷电状态是否位于10％～40％，并分别将磷酸铁锂电池包中各电池单元的电压数据与最小电压值之间的差值与预设的电压阈值进行比较（S103）；若判断出荷电状态位于10％～40％，且存在电压数据与最小电压值之间的差值大于或者等于电压阈值的电池单元，对该电池单元执行放电（S104）。通过所述均衡方法提高了磷酸铁锂电池包中各电池单元之间荷电状态的一致性，延长了磷酸铁锂电池包的使用寿命。

Description

电池包均衡方法、电池管理系统及电池系统 【技术领域】
本发明涉及电池技术领域，尤其涉及一种电池包均衡方法、电池管理系统及电池系统。
【背景技术】
磷酸铁锂电池包(LiFePO4Battery Pack)具有典型的充放电平台，这种优异的电性能以及高循环寿命、高安全性的特性，使该产品被广泛应用在电动汽车和储能领域。
磷酸铁锂电池系统由磷酸铁锂电池包和电池管理系统组成。磷酸铁锂电池包由数量较多的电池单元经串联或并联或混联组成。电池单元因原材料以及制造过程中存在变异，因而电池单元之间的荷电状态(State of Charge，SoC)并不完全相同。由此导致磷酸铁锂电池系统在使用过程中，经过反复充电、放电以及日历存储，各电池单元之间的荷电不均衡度逐渐增大，直接影响磷酸铁锂电池系统的功率能力以及可用能量的发挥，降低了磷酸铁锂电池包的使用寿命。
【发明内容】
有鉴于此，本发明提供一种电池包均衡方法、电池管理系统及电池系统，提高了磷酸铁锂电池包中各电池单元之间荷电状态的一致性，延长了磷酸铁锂电池包的使用寿命。
本发明实施例的一方面，提供一种电池包均衡方法，包括：
检测磷酸铁锂电池包中各电池单元的电压数据，并根据各电池单元的电压数据，获取所述磷酸铁锂电池包的荷电状态；
获取所述电压数据中的最小电压值；
判断所述荷电状态是否位于10％～40％，并分别将所述磷酸铁锂电池包中各电池单元的电压数据与所述最小电压值之间的差值与预设的电压阈值进行比较；
若判断出所述荷电状态位于10％～40％，且存在电压数据与所述最小电压值之间的差值大于或者等于所述电压阈值的电池单元，对所述磷酸铁锂电池包中电压数据与所述最小电压值之间的差值大于或者等于所述电压阈值的电池单元执行放电。
如上所述的方面和任一可能的实现方式，进一步提供一种实现方式，所述方法还包括：
当所述磷酸铁理电池包中放电的电池单元的电压数据达到指定条件时，停止对所述磷酸铁理电池包中电压数据与所述最小电压值之间的差值大于或者等于所述电压阈值的电池单元的放电。
如上所述的方面和任一可能的实现方式，进一步提供一种实现方式，所述指定条件包括：所述磷酸铁理电池包中放电的电池单元的电压数据与所述最小电压值一致。
如上所述的方面和任一可能的实现方式，进一步提供一种实现方式，检测磷酸铁锂电池包中各电池单元的电压数据，包括：
在休眠模式下，检测磷酸铁锂电池包中各电池单元的电压数据；
其中，所述休眠模式包括所述磷酸铁锂电池包没有输入能量或者输出能量。
如上所述的方面和任一可能的实现方式，进一步提供一种实现方式，每个电池单元包括一个电池单体，或者，每个电池单元包括并联的至少两个电池单体。
如上所述的方面和任一可能的实现方式，进一步提供一种实现方式，所述磷酸铁锂电池包中各电池单体包括磷酸铁锂在阴极活性物质中的固含量大于或者等于90％的锂离子电池单体。
本发明实施例的一方面，提供一种电池管理系统，包括：
检测模块，用于检测磷酸铁锂电池包中各电池单元的电压数据；
电量估算模块，用于根据各电池单元的电压数据，获取所述磷酸铁锂电池 包的荷电状态；
均衡模块，用于获取所述电压数据中的最小电压值；以及，判断所述荷电状态是否位于10％～40％，并分别将所述磷酸铁锂电池包中各电池单元的电压数据与所述最小电压值之间的差值与预设的电压阈值进行比较；以及，若判断出所述荷电状态位于10％～40％，且存在电压数据与所述最小电压值之间的差值大于或者等于所述电压阈值的电池单元，对所述磷酸铁锂电池包中电压数据与所述最小电压值之间的差值大于或者等于所述电压阈值的电池单元执行放电。
如上所述的方面和任一可能的实现方式，进一步提供一种实现方式，所述均衡模块，还用于：
当所述磷酸铁理电池包中放电的电池单元的电压数据达到指定条件时，停止对所述磷酸铁理电池包中电压数据与所述最小电压值之间的差值大于或者等于所述电压阈值的电池单元的放电。
如上所述的方面和任一可能的实现方式，进一步提供一种实现方式，所述指定条件包括：所述磷酸铁理电池包中放电的电池单元的电压数据与所述最小电压值一致。
如上所述的方面和任一可能的实现方式，进一步提供一种实现方式，所述检测模块，具体用于：在休眠模式下，检测磷酸铁锂电池包中各电池单元的电压数据；
其中，所述休眠模式包括所述磷酸铁锂电池包没有输入能量或者输出能量。
如上所述的方面和任一可能的实现方式，进一步提供一种实现方式，每个电池单元包括一个电池单体，或者，每个电池单元包括并联的至少两个电池单体。
本发明实施例的一方面，提供一种电池系统，包括磷酸铁锂电池包以及上述电池管理系统。
如上所述的方面和任一可能的实现方式，进一步提供一种实现方式，所述磷酸铁锂电池包中包括磷酸铁锂在阴极活性物质中的固含量大于或者等于90％的锂离子电池单体。
由以上技术方案可以看出，本发明实施例具有以下有益效果：
本发明实施例所提供的技术方案中，通过根据磷酸铁锂电池包的荷电状态以及磷酸铁锂电池包中各电池单元的电压数据与最小电压值之间的差值，判断是否满足均衡启动条件，如果满足均衡启动条件，即荷电状态处于低端(即荷电状态位于10％～40％)，且存在电压数据与最小电压值之间的差值大于或者等于电压阈值的电池单元，则对满足该均衡启动条件的电池单元进行放电，从而使磷酸铁锂电池包中电压数据较高的电池单元的电压与最小电压值趋于一致，减少了各电池单元之间的荷电不均衡度，有效的实现了电池单元之间的荷电均衡，从而避免了荷电不均衡度较大所导致的磷酸铁锂电池系统的功率能力以及可用能量的发挥的问题，延长了磷酸铁锂电池包的使用寿命。而且，通过低端均衡可以有效的提高磷酸铁锂电池包的均衡效率。
【附图说明】
为了更清楚地说明本发明实施例的技术方案，下面将对实施例中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本发明的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动性的前提下，还可以根据这些附图获得其它的附图。
图1是本发明实施例所提供的电池包均衡方法的实施例一的流程示意图；
图2是本发明实施例所提供的电池包均衡方法的实施例二的流程示意图；
图3是本发明实施例所提供的磷酸铁锂电池包的荷电状态与电压的关系曲线图；
图4是本发明实施例所提供的电池包均衡方法的实施例三的流程示意图；
图5是本发明实施例所提供的电池管理系统的实施例一的功能方块图；
图6是本发明实施例所提供的电池管理系统的实施例二的功能方块图；
图7是本发明实施例所提供的电池系统的功能方块图。
【具体实施方式】
为了更好的理解本发明的技术方案，下面结合附图对本发明实施例进行详细描述。
应当明确，所描述的实施例仅仅是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有作出创造性劳动前提下所获得的所有其它实施例，都属于本发明保护的范围。
在本发明实施例中使用的术语是仅仅出于描述特定实施例的目的，而非旨在限制本发明。在本发明实施例和所附权利要求书中所使用的单数形式的“一种”、“所述”和“该”也旨在包括多数形式，除非上下文清楚地表示其他含义。
应当理解，本文中使用的术语“和/或”仅仅是一种描述关联对象的关联关系，表示可以存在三种关系，例如，A和/或B，可以表示：单独存在A，同时存在A和B，单独存在B这三种情况。另外，本文中字符“/”，一般表示前后关联对象是一种“或”的关系。
取决于语境，如在此所使用的词语“如果”可以被解释成为“在......时”或“当......时”或“响应于确定”或“响应于检测”。类似地，取决于语境，短语“如果确定”或“如果检测(陈述的条件或事件)”可以被解释成为“当确定时”或“响应于确定”或“当检测(陈述的条件或事件)时”或“响应于检测(陈述的条件或事件)”。
磷酸铁锂电池包具有典型的充放电平台，这种优异的电性能以及高循环寿命、高安全性的特性，使该产品被广泛应用在电动汽车和储能领域。磷酸铁锂电池系统由磷酸铁锂电池包和电池管理系统组成。磷酸铁锂电池包由数量较多的电池单元经串联或并联或混联组成。电池单元因原材料以及制造过程中存在变异，因而电池单元之间的荷电状态并不完全相同。由此导致磷酸铁锂电池系统在使用过程中，经过反复充电、放电以及日历存储，各电池单元之间的荷电不均衡度逐渐增大，直接影响磷酸铁锂电池系统的功率能力以 及可用能量的发挥，降低了磷酸铁锂电池包的使用寿命。因此，十分有必要对磷酸铁锂电池包进行均衡。
对磷酸铁锂电池包进行均衡的方法主要有两种，一种是高端均衡的方法，另一种是低端均衡的方法。需要说明的是，低端均衡指的是在荷电状态位于10％～40％且压差满足均衡启动条件下启动均衡，高端均衡指的是在荷电状态位于90％～100％且压差满足均衡启动条件下启动均衡。在选取均衡方法之前，对若干样品做了不同的实验，如表1所示，高端均衡使用了三个磷酸铁锂电池包样品来做实验，在高端均衡前，荷电不均衡度分别为17.1％、27.6％、22.9％，高端均衡以后，三个样品的荷电不均衡度分别变为13.5％、20.4％、22.9％。电压平均值和与最小电压值之间的差值，即表中的压差，分别从24mV、29mV、7mV，降到5mV、4mV、6mV。可以理解的是，荷电不均衡度ΔSoC可以有以下两种计算方式，一种是磷酸铁锂电池包中各电池单元的荷电状态的平均值与荷电状态的最小值之间的差值，另一种是磷酸铁锂电池包中各电池单元的荷电状态的最大值与荷电状态的最小值之间的差值。本实施例中提到的荷电不均衡度是采用磷酸铁锂电池包中各电池单元的荷电状态的平均值与荷电状态的最小值之间的差值。采用低端均衡的方法对磷酸铁锂电池包进行均衡时，使用了五个样品，且其中两个样品，即样品2和样品3与高端均衡时使用的样品相同。由表1可以看出，五个样品通过低端均衡的方式，荷电不均衡度由27.6％、22.9％、6.1％、5.4％、4.8％，分别降到2.0％、1.6％、1.8％、1.3％、1.1％，压差由16mV、62mV、26mV、24mV、18mV，分别降到8mV、8mV、6mV、4mV、4mV。由此可见，低端均衡与高端均衡相比，对于磷酸铁锂电池包中各电池单元之间荷电不均衡度的改善更为明显。因此以下实施例涉及到的有效的均衡方法都是低端均衡的方法。
表1
Figure PCTCN2016074116-appb-000001
Figure PCTCN2016074116-appb-000002
实施例一
本发明实施例给出一种电池包均衡方法，请参考图1，其为本发明实施例所提供的电池包均衡方法的实施例一的流程示意图，如图所示，该方法包括以下步骤：
S101，检测磷酸铁锂电池包中各电池单元的电压数据，并根据各电池单元的电压数据，获取所述磷酸铁锂电池包的荷电状态。
S102，获取所述电压数据中的最小电压值。
S103，判断所述荷电状态是否位于10％～40％，并分别将所述磷酸铁锂电池包中各电池单元的电压数据与所述最小电压值之间的差值与预设的电压阈值进行比较。
S104，若判断出所述荷电状态位于10％～40％，且存在电压数据与所述最小电压值之间的差值大于或者等于所述电压阈值的电池单元，对所述磷酸铁锂电池包中电压数据与所述最小电压值之间的差值大于或者等于所述电压阈值的电池单元执行放电。
实施例二
请参考图2，其为本发明实施例所提供的电池包均衡方法的实施例二的流程示意图，本实施例为实施例一的一种具体实现方法。如图所示，该方法包括以下步骤：
S201，检测磷酸铁锂电池包中各电池单元的电压数据，并根据各电池单 元的电压数据，获取所述磷酸铁锂电池包的荷电状态。
具体的，本发明实施例中，可以在休眠模式下，检测磷酸铁锂电池包中各电池单元的电压数据。
需要说明的是，所述休眠模式指的是磷酸铁锂电池包没有输入能量或者输出能量。
需要说明的是，本发明实施例中，磷酸铁锂电池包中通常由数量较多的电池单元经串联或并联或混联组成。其中，每个电池单元中可以包括一个电池单体，或者，每个电池单元中也可以包括并联的至少两个电池单体，也即，每个电池单元可以是由多个电池单体并联组成的。
在本发明实施例中，所述磷酸铁锂电池包各电池单体包括磷酸铁锂在阴极活性物质中的固含量大于或者等于90％的锂离子电池单体。
本发明实施中，可以在所述磷酸铁锂电池包中放电的电池单元的电压数据达到预设条件之前，放电过程可以间歇完成，也即，放电持续预设时长1后，磷酸铁理电池包进入休眠模式，维持休眠模式的时长达到预设时长2，然后唤醒电池管理系统，重新执行S201～S207的均衡过程。其中，预设时长1和预设时长2可以根据均衡操作的执行主体的硬件特性以及均衡效率来综合考虑并进行设置，例如，可以使5分钟、10分钟、1小时或者3小时等，预设时长1与预设时长2可以相同或这样也可以不同。
当磷酸铁锂电池包在休眠模式下时，对磷酸铁锂电池包中的各个电池单元的荷电状态数据进行检测，荷电状态表示的是蓄电池使用一段时间或长期搁置不用后的剩余容量与其完全充电状态的容量的比值，可以采用百分数来表示。
本发明实施例中，可以对磷酸铁锂电池包中各电池单元的电压数据进行检测并记录，如各电池单元的电压数据可以依次记为U1、U2、......、UN，其中，N表示磷酸铁锂电池包中电池单元的数量。
本发明实施例中，在检测到磷酸铁锂电池包中各电池单元的电压数据之后，可以根据磷酸铁锂电池包中各电池单元的电压数据，很快获取到磷酸铁 锂电池包的荷电状态。
需要说明的是，荷电状态指的是磷酸铁锂电池包使用一段时间或者长期放置不用后，剩余电量与充满电后的电量的比值，可以利用百分数表示。
S202，获取所述电压数据中的最小电压值。
举例说明，可以根据由大到小的顺序对各电池单元的电压数据进行排序，以获取其中最小电压值。或者，还可以根据由小到大的顺序对各电池单元的电压数据进行排序，以获取其中最小电压值。
S203，判断所述荷电状态是否位于10％～40％，并分别将所述磷酸铁锂电池包中各电池单元的电压数据与所述最小电压值之间的差值与预设的电压阈值进行比较。若判断出所述荷电状态位于10％～40％，且存在电压数据与所述最小电压值之间的差值大于或者等于所述电压阈值的电池单元，执行S204，反之，执行S207。
具体的，在获取到磷酸铁锂电池包的荷电状态后，进一步判断该荷电状态是否位于10％～40％，同时，分别计算各电池单元的电压数据与最小电压值之间的差值，如各电池单元的压差表示为ΔU＝Ui-min{U1，U2，U3，…，UN}，其中，i＝1，2，3，…，N；然后将计算出的各差值分别与预设的电压阈值进行比较。
如果荷电状态位于10％～40％，且存在至少一个电压数据与所述最小电压值之间的差值大于或者等于所述电压阈值的电池单元，说明磷酸铁锂电池包的荷电状态处于低端，满足均衡启动条件，且说明该至少一个电池单元的电压数据与最小电压值之间的差值较大，需要对磷酸铁锂电池包中的电池单元执行放电，所以继续执行S204。反之，其他情况下，执行S207。
其中，其他情况包括：荷电状态位于10％～40％，但不存在电压数据与所述最小电压值之间的差值大于或者等于所述电压阈值的电池单元。或者，荷电状态不位于10％～40％，但存在电压数据与所述最小电压值之间的差值大于或者等于所述电压阈值的电池单元。或者，荷电状态不位于10％～40％，且不存在电压数据与所述最小电压值之间的差值大于或者等于所述电压阈值 的电池单元。
需要说明的是，所有电池单元的电压数据与所述最小电压值之间的差值都小于所述电压阈值，说明该电池单元的电压数据与最小电压值之间的差值较小，不需要执行荷电均衡，因此执行S207。而且，如果荷电状态不位于10％～40％，说明磷酸铁锂电池包的荷电状态没有处于低端，可能处于其他荷电区间(如0～10％或者40％～100％)，不满足均衡启动条件，不需要对磷酸铁锂电池包中的电池单元执行放电，所以执行S207。
其中，预设的电压阈值可以通过实验来确定。例如，预设的电压阈值可以等于8mV。
需要说明的是，本发明实施例中，通过磷酸铁锂电池包中各电池单元的电压数据与最小电压值之间的差值，以及磷酸铁锂电池包的荷电状态，来判断是否满足均衡启动条件，若满足均衡启动条件，进行电池单元的均衡操作。反之，若不满足均衡启动条件，或者，就不进行电池单元的均衡操作，结束当前流程。
请参考图3，其为本发明实施例所提供的磷酸铁锂电池包的荷电状态与电压的关系曲线图，该关系曲线图可以通过充放电设备对磷酸铁锂电池包中的电池单元进行测试得到。如图3所示，磷酸铁锂电池包的荷电状态在10％～40％区间时，荷电状态与电压具有强相关性，因此，在这个区间内，根据各电池单元的电压数据估计以及修正荷电状态这种方式，可以提高计算出的荷电状态的准确度，因而均衡效果好。在10％～40％区间中，优选的，荷电状态区间可以为15％～35％。
需要说明的是，磷酸铁锂电池包的荷电状态在90％～100％时，该区间较窄，且由于磷酸铁锂材料的极化特性以及磷酸铁锂电池包中电池单元之间的差异性，电压降至平台区，压差较小，不容易触发均衡或者触发均衡后实施效果不好。荷电状态在平台区40％～90％时，在该区域内荷电状态与电压几乎无相关性，不能触发均衡或者会引起误均衡。荷电状态在0～10％时，为防止磷酸铁锂电池包中电池单元过放，不可以用作均衡区间，因此，要采用低 端均衡的方法对磷酸铁锂电池包中的电池单元进行均衡，就要在磷酸铁锂电池包的荷电状态在10％～40％时进行。
S204，对所述磷酸铁锂电池包中电压数据与所述最小电压值之间的差值大于或者等于所述电压阈值的电池单元执行放电。
具体的，本发明实施例中，在判断出磷酸铁锂电池包的荷电状态位于10％～40％，且存在磷酸铁锂电池包中电压数据与最小电压值之间的差值大于或者等于电压阈值的电池单元时，对该磷酸铁锂电池包中电压数据与最小电压值之间的差值大于或者等于电压阈值的电池单元执行放电，从而可以通过放电，使得磷酸铁锂电池包中原来电压较高的电池单元在放电之后，电压数据与磷酸铁锂电池包中电压数据最小的电池单元的电压趋于一致，实现磷酸铁锂电池包的均衡，降低了磷酸铁锂电池包的荷电不均衡度。
S205，判断所述磷酸铁理电池包中放电的电池单元的电压数据是否达到指定条件，如果是，执行S206，如果否，执行S201。
具体的，本发明实施例中，在对磷酸铁锂电池包中电压数据与所述最小电压值之间的差值大于或者等于所述电压阈值的电池单元执行放电之后，还需要判断所述磷酸铁理电池包中放电的电池单元的电压数据是否达到指定条件，如果判断出所述磷酸铁理电池包中放电的电池单元的电压数据达到指定条件，执行S206。反之，如果判断出所述磷酸铁理电池包中放电的电池单元的电压数据没有达到指定条件，执行S201，也即，重新进行检测、估算、判断以及均衡等操作。
在一个具体的实现过程中，所述指定条件可以包括：所述磷酸铁理电池包中放电的电池单元的电压数据与所述最小电压值一致。
S206，停止对所述磷酸铁理电池包中电压数据与所述最小电压值之间的差值大于或者等于所述电压阈值的电池单元的放电。
具体的，本发明实施例中，在对磷酸铁锂电池包中电压数据与所述最小电压值之间的差值大于或者等于所述电压阈值的电池单元执行放电之后，还需要在确定磷酸铁理电池包中放电的电池单元的电压数据达到指定条件时，停止对 所述磷酸铁理电池包中电压数据与所述最小电压值之间的差值大于或者等于所述电压阈值的电池单元的放电，在停止对该电池单元的放电之后，实现了磷酸铁锂电池包的荷电均衡。
S207，不对所述磷酸铁锂电池包中的电池单元执行放电，结束流程。
实施例三
请参考图4，其为本发明实施例所提供的电池包均衡方法的实施例三的流程示意图，本实施例为实施例一的另一具体实现方法。如图所示，该方法包括以下步骤：
S401，将磷酸铁锂电池包充满电，然后放电至磷酸铁锂电池包的荷电状态位于20％～25％。
S402，在休眠模式下，检测并记录磷酸铁锂电池包中串联的100节电池单元的电压数据，记为UN，N等于1，2，3，...，100。
S403，计算磷酸铁锂电池包中各电池单元的电压数据与最小电压值之间的差值。
S404，对磷酸铁锂电池包中电压数据与最小电压值之间的差值大于8mV的电池单元进行放电。
S405，每间隔一段时间重新执行一次磷酸铁锂电池包的低端均衡，即执行S401～S405，直到电压数据较高的电池单元的电压数据与电压最小值趋于一致时，完成磷酸铁锂电池包的均衡。
本发明实施例进一步给出实现上述方法实施例中各步骤及方法的装置实施例。
请参考图5，其为本发明实施例所提供的电池管理系统的实施例一的功能方块图。如图所示，该电池管理系统包括：
检测模块51，用于检测磷酸铁锂电池包中各电池单元的电压数据；
电量估算模块52，用于根据各电池单元的电压数据，获取所述磷酸铁锂电池包的荷电状态；
均衡模块53，用于获取所述电压数据中的最小电压值；以及，判断所述荷 电状态是否位于10％～40％，并分别将所述磷酸铁锂电池包中各电池单元的电压数据与所述最小电压值之间的差值与预设的电压阈值进行比较；以及，若判断出所述荷电状态位于10％～40％，且存在电压数据与所述最小电压值之间的差值大于或者等于所述电压阈值的电池单元，对所述磷酸铁锂电池包中电压数据与所述最小电压值之间的差值大于或者等于所述电压阈值的电池单元执行放电。
可选的，所述均衡模块53，还用于：
当所述磷酸铁理电池包中放电的电池单元的电压数据达到指定条件时，停止对所述磷酸铁理电池包中电压数据与所述最小电压值之间的差值大于或者等于所述电压阈值的电池单元的放电。
优选的，所述指定条件包括：所述磷酸铁理电池包中放电的电池单元的电压数据与所述最小电压值一致。
优选的，所述检测模块51，具体用于：在休眠模式下，检测磷酸铁锂电池包中各电池单元的电压数据；其中，所述休眠模式包括所述磷酸铁锂电池包没有输入能量或者输出能量。
优选的，每个电池单元包括一个电池单体，或者，每个电池单元包括并联的至少两个电池单体。
优选的，所述磷酸铁锂电池包中各电池单体包括磷酸铁锂在阴极活性物质中的固含量大于或者等于90％的锂离子电池单体。
由于本实施例中的各单元能够执行图1、图2或者图4所示的方法，本实施例未详细描述的部分，可参考对图1、图2或者图4的相关说明。
请参考图6，其为本发明实施例所提供的电池管理系统的实施例二的功能方块图。如图所示，该电池管理系统还可以包括：充电模块54，用于将磷酸铁锂电池包充满电，然后放电至磷酸铁锂电池包的荷电状态位于10％～40％。
请参考图7，其为本发明实施例所提供的电池系统的功能方块图。如图7所示，该电池系统包括：磷酸铁锂电池包70以及上述电池管理系统71。
可以理解的是，所述磷酸铁锂电池包中包括磷酸铁锂在阴极活性物质中 的固含量大于或者等于90％的锂离子电池单体。
本发明实施例的技术方案具有以下有益效果：
本发明实施例所提供的技术方案中，通过根据磷酸铁锂电池包的荷电状态以及磷酸铁锂电池包中各电池单元的电压数据与最小电压值之间的差值，判断是否满足均衡启动条件，如果满足均衡请条件，即荷电状态处于低端(荷电状态位于10％～40％)，且存在电压数据与最小电压值之间的差值大于或者等于电压阈值的电池单元，则对满足该均衡启动条件的电池单元进行放电，从而使磷酸铁锂电池包中电压数据较高的电池单元的电压与最小电压值趋于一致，减少了各电池单元之间的荷电不均衡度，有效的实现了电池单元之间的荷电均衡，从而避免了荷电不均衡度较大所导致的磷酸铁锂电池系统的功率能力以及可用能量的发挥的问题，延长了磷酸铁锂电池包的使用寿命。而且，通过低端均衡可以有效的提高磷酸铁锂电池包的均衡效率。
另外，本发明实施例所提供的技术方案与现有技术中在其他荷电状态(荷电状态位于40％～100％)启动均衡相比，荷电均衡效果更好，而且能够防止误均衡，提升了均衡效果，最大程度上降低了电池单元之间的荷电不均衡度，改善电池单元之间的不一致性，从而延长了磷酸铁锂电池包的使用寿命。
所属领域的技术人员可以清楚地了解到，为描述的方便和简洁，上述描述的系统，装置和单元的具体工作过程，可以参考前述方法实施例中的对应过程，在此不再赘述。
在本发明所提供的几个实施例中，应该理解到，所揭露的系统，装置和方法，可以通过其它的方式实现。例如，以上所描述的装置实施例仅仅是示意性的，例如，所述单元的划分，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式，例如，多个单元或组件可以结合或者可以集成到另一个系统，或一些特征可以忽略，或不执行。另一点，所显示或讨论的相互之间的耦合或直接耦合或通信连接可以是通过一些接口，装置或单元的间接耦合或通信连接，可以是电性，机械或其它的形式。
所述作为分离部件说明的单元可以是或者也可以不是物理上分开的，作为单元显示的部件可以是或者也可以不是物理单元，即可以位于一个地方，或者也可以分布到多个网络单元上。可以根据实际的需要选择其中的部分或者全部单元来实现本实施例方案的目的。
另外，在本发明各个实施例中的各功能单元可以集成在一个处理单元中，也可以是各个单元单独物理存在，也可以两个或两个以上单元集成在一个单元中。上述集成的单元既可以采用硬件的形式实现，也可以采用硬件加软件功能单元的形式实现。
上述以软件功能单元的形式实现的集成的单元，可以存储在一个计算机可读取存储介质中。上述软件功能单元存储在一个存储介质中，包括若干指令用以使得一台计算机装置(可以是个人计算机，服务器，或者网络装置等)或处理器(Processor)执行本发明各个实施例所述方法的部分步骤。而前述的存储介质包括：U盘、移动硬盘、只读存储器(Read-Only Memory，ROM)、随机存取存储器(Random Access Memory，RAM)、磁碟或者光盘等各种可以存储程序代码的介质。
以上所述仅为本发明的较佳实施例而已，并不用以限制本发明，凡在本发明的精神和原则之内，所做的任何修改、等同替换、改进等，均应包含在本发明保护的范围之内。

Claims (13)

  1. 一种电池包均衡方法，其特征在于，包括：
    检测磷酸铁锂电池包中各电池单元的电压数据，并根据各电池单元的电压数据，获取所述磷酸铁锂电池包的荷电状态；
    获取所述电压数据中的最小电压值；
    判断所述荷电状态是否位于10％～40％，并分别将所述磷酸铁锂电池包中各电池单元的电压数据与所述最小电压值之间的差值与预设的电压阈值进行比较；
    若判断出所述荷电状态位于10％～40％，且存在电压数据与所述最小电压值之间的差值大于或者等于所述电压阈值的电池单元，对所述磷酸铁锂电池包中电压数据与所述最小电压值之间的差值大于或者等于所述电压阈值的电池单元执行放电。
  2. 根据权利要求1所述的电池包均衡方法，其特征在于，所述方法还包括：
    当所述磷酸铁理电池包中放电的电池单元的电压数据达到指定条件时，停止对所述磷酸铁理电池包中电压数据与所述最小电压值之间的差值大于或者等于所述电压阈值的电池单元的放电。
  3. 根据权利要求2所述的电池包均衡方法，其特征在于，所述指定条件包括：所述磷酸铁理电池包中放电的电池单元的电压数据与所述最小电压值一致。
  4. 根据权利要求1所述的电池包均衡方法，其特征在于，检测磷酸铁锂电池包中各电池单元的电压数据，包括：
    在休眠模式下，检测磷酸铁锂电池包中各电池单元的电压数据；
    其中，所述休眠模式包括所述磷酸铁锂电池包没有输入能量或者输出能量。
  5. 根据权利要求1至4中任一项所述的电池包均衡方法，其特征在于，每个电池单元包括一个电池单体，或者，每个电池单元包括并联的至少两个电池单体。
  6. 根据权利要求5所述的电池包均衡方法，其特征在于，所述磷酸铁锂电 池包中各电池单体包括磷酸铁锂在阴极活性物质中的固含量大于或者等于90％的锂离子电池单体。
  7. 一种电池管理系统，其特征在于，所述电池管理系统包括：
    检测模块，用于检测磷酸铁锂电池包中各电池单元的电压数据；
    电量估算模块，用于根据各电池单元的电压数据，获取所述磷酸铁锂电池包的荷电状态；
    均衡模块，用于获取所述电压数据中的最小电压值；以及，判断所述荷电状态是否位于10％～40％，并分别将所述磷酸铁锂电池包中各电池单元的电压数据与所述最小电压值之间的差值与预设的电压阈值进行比较；以及，若判断出所述荷电状态位于10％～40％，且存在电压数据与所述最小电压值之间的差值大于或者等于所述电压阈值的电池单元，对所述磷酸铁锂电池包中电压数据与所述最小电压值之间的差值大于或者等于所述电压阈值的电池单元执行放电。
  8. 根据权利要求7所述的电池管理系统，其特征在于，所述均衡模块，还用于：
    当所述磷酸铁理电池包中放电的电池单元的电压数据达到指定条件时，停止对所述磷酸铁理电池包中电压数据与所述最小电压值之间的差值大于或者等于所述电压阈值的电池单元的放电。
  9. 根据权利要求8所述的电池管理系统，其特征在于，所述指定条件包括：所述磷酸铁理电池包中放电的电池单元的电压数据与所述最小电压值一致。
  10. 根据权利要求7所述的电池管理系统，其特征在于，所述检测模块，具体用于：在休眠模式下，检测磷酸铁锂电池包中各电池单元的电压数据；
    其中，所述休眠模式包括所述磷酸铁锂电池包没有输入能量或者输出能量。
  11. 根据权利要求7至10中任一项所述的电池管理系统，其特征在于，每个电池单元包括一个电池单体，或者，每个电池单元包括并联的至少两个电池单体。
  12. 一种电池系统，其特征在于，包括磷酸铁锂电池包以及权利要求7至11中任一项所述的电池管理系统。
  13. 根据权利要求12所述的电池系统，其特征在于，所述磷酸铁锂电池包中包括磷酸铁锂在阴极活性物质中的固含量大于或者等于90％的锂离子电池单体。
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