CN117498496A

CN117498496A - Battery cluster balanced discharging method and battery cluster balanced system

Info

Publication number: CN117498496A
Application number: CN202311479878.3A
Authority: CN
Inventors: 熊路兵; 袁浩兵
Original assignee: Shenzhen Gefuen New Energy Technology Co ltd
Current assignee: Shenzhen Gefuen New Energy Technology Co ltd
Priority date: 2023-11-07
Filing date: 2023-11-07
Publication date: 2024-02-02

Abstract

The invention relates to a battery cluster balanced discharging method and a battery cluster balanced system, which relate to the field of photovoltaic energy storage, wherein the battery cluster comprises at least five batteries in initial states, and the batteries in the at least five initial states are connected with each other; the method comprises the following steps: acquiring at least five initial voltages of batteries in at least five initial states of the battery cluster; judging whether the deviation degree among at least five initial voltages accords with a preset condition; and if the deviation degree between the at least five initial voltages does not meet the preset condition, performing active equalization on the at least five batteries in the initial state, and then performing passive equalization on the batteries in the initial state to obtain the batteries in the at least five balanced states. The method and the device have the technical effects that firstly, the energy utilization efficiency can be increased, secondly, equalization can be automatically completed without manual configuration, thirdly, the condition of SOC jump can be avoided, and customer experience is optimized.

Description

Battery cluster balanced discharging method and battery cluster balanced system

Technical Field

The invention relates to the field of photovoltaic energy storage, in particular to a battery cluster balanced discharging method and a battery cluster balanced system.

Background

In recent years, the development of new energy industry is rapid, and a household photovoltaic energy storage system is generated, and a battery cluster is widely used for energy storage in the industry. In the use process of the battery clusters, due to the problems of inconsistent internal resistance of the battery cells, inconsistent capacity of the battery cells, wrong battery cell allocation, different battery batches and the like, voltages among the battery cells in the battery are inconsistent, and then the voltages among the battery clusters are inconsistent, and finally the conditions of reduced available capacity of the battery clusters or SOC jump occur.

Moreover, the heat is too high in the balanced discharging process of the battery cluster, so that the performance index of the battery cluster is weakened, and the service life of the battery cluster is further influenced. Therefore, developing a reasonable battery cluster balanced discharge method has become a technical problem to be solved in the industry.

Disclosure of Invention

The technical problems to be solved by the invention are as follows: how to design a battery cluster balanced discharge method can effectively solve the problems.

The embodiment of the invention provides a battery cluster balanced discharging method and a battery cluster balanced system, which have the technical effects that firstly, the energy utilization efficiency can be increased, secondly, the balance can be automatically completed without manual configuration, and thirdly, the condition of SOC jump can be avoided and the customer experience can be optimized.

In a first aspect, the present invention provides a battery cluster balanced discharging method, where a battery cluster includes at least five batteries in an initial state, and the at least five batteries in the initial state are connected with each other; the method comprises the following steps: s1, acquiring at least five initial voltages of batteries in at least five initial states of the battery cluster; s2, judging whether the deviation degree among at least five initial voltages accords with a preset condition; and S3, if the deviation degree between the at least five initial voltages does not meet the preset condition, performing active equalization on the battery in the at least five initial states, and then performing passive equalization on the battery in the at least five initial states to obtain the battery in the at least five equalization states.

The battery cluster balanced discharge method further comprises the following steps: and if the deviation degree between the at least five initial voltages accords with the preset condition, directly carrying out passive equalization on the batteries in the at least five initial states to obtain the batteries in the at least five equalization states.

The further technical proposal is that at least five initial voltages comprise an initial maximum voltage and an initial minimum voltage; the meeting of the preset conditions comprises the following steps: simultaneously satisfying the first condition and the second condition; the first condition is that a deviation value between the initial maximum voltage and the initial minimum voltage is smaller than or equal to a preset deviation threshold value; the second condition is that the variance value of at least five initial voltages is less than or equal to a preset variance threshold.

The battery cluster comprises six batteries in initial states; the acquiring at least five initial voltages of the batteries in at least five initial states of the battery cluster includes: the voltages of the batteries in the six initial states of the battery cluster are acquired, and the voltages are sequentially set to be a first initial voltage, a second initial voltage, a third initial voltage, a fourth initial voltage, a fifth initial voltage and a sixth initial voltage from small to large.

The further technical scheme is that the judging whether the deviation degree between at least five initial voltages accords with the preset condition comprises the following steps: and judging whether the deviation degree among the first initial voltage, the second initial voltage, the third initial voltage, the fourth initial voltage, the fifth initial voltage and the sixth initial voltage meets the first condition and the second condition at the same time.

According to a further technical scheme, if the deviation degree between at least five initial voltages does not meet a preset condition, performing active equalization on the battery in at least five initial states and then performing passive equalization on the battery in at least five initial states, so as to obtain the battery in at least five equalization states, wherein the method comprises the following steps: and if the deviation degree of the six initial voltages does not meet the preset condition, performing active equalization on the batteries in the six initial states, and then performing passive equalization on the batteries in the six initial states to obtain the batteries in the six equalization states.

The further technical scheme is that the method comprises the steps of performing active equalization on the six batteries in the initial state and then performing passive equalization on the batteries in the initial state to obtain the six batteries in the equalization state, and comprises the following steps: controlling the second battery to discharge until the first initial voltage of the first battery changes to a first range voltage and the second initial voltage of the second battery changes to the first range voltage; controlling the third battery to discharge until the first range voltage is changed to the second range voltage and the third initial voltage of the third battery is changed to the second range voltage; controlling the fourth battery to discharge until the second range voltage is changed to the third range voltage and the fourth initial voltage of the fourth battery is changed to the third range voltage; controlling the fifth battery to discharge until the third range voltage is changed to the fourth range voltage and the fifth initial voltage of the fifth battery is changed to the fourth range voltage; controlling the discharge of the sixth battery until the fourth range voltage is changed to the fifth range voltage and the sixth initial voltage of the sixth battery is changed to the fifth range voltage; and controlling the six batteries to perform passive equalization to obtain the batteries in six equalization states.

The further technical scheme is that in the process from controlling the second battery to controlling the sixth battery to discharge, one battery discharges and five batteries charge, and the voltage increment value of the five battery charges does not exceed the preset voltage range.

The further technical scheme is that before the obtaining at least five initial voltages of the batteries in at least five initial states of the battery cluster, the method comprises the following steps: discharging the battery clusters until the discharge value of the battery management system becomes zero, and sampling the batteries in at least five initial states.

In a second aspect, the invention proposes a battery cluster equalization system comprising means for performing the method according to the first aspect.

In the using process of the battery clusters, due to the problems of inconsistent internal resistance, inconsistent capacity, wrong battery allocation, different battery batches and the like of the battery cores, the voltages among the battery cores in the battery are inconsistent, so that the voltages among the battery clusters are inconsistent, and finally, the situation that the available capacity of the battery clusters is reduced or SOC jump occurs; the method and the device have the technical effects that firstly, the energy utilization efficiency can be increased, secondly, equalization can be automatically completed without manual configuration, thirdly, the condition of SOC jump can be avoided, and customer experience is optimized.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and together with the description, serve to explain the principles of the invention.

In order to more clearly illustrate the embodiments of the invention or the technical solutions of the prior art, the drawings which are used in the description of the embodiments or the prior art will be briefly described, and it will be obvious to a person skilled in the art that other drawings can be obtained from these drawings without inventive effort.

Fig. 1 is a schematic flow chart of a battery cluster balanced discharge method according to an embodiment of the present invention.

Fig. 2 is another flow chart of a battery cluster balanced discharge method according to an embodiment of the present invention.

Fig. 3 is a schematic signal connection diagram corresponding to a battery cluster equalization discharging method according to an embodiment of the present invention.

Fig. 4 is a schematic signal connection diagram corresponding to a battery cluster equalization discharging method according to an embodiment of the present invention.

Fig. 5 is a schematic diagram of a battery corresponding to the battery cluster balanced discharge method according to the embodiment of the present invention.

Fig. 6 is a block diagram of a battery cluster equalization system according to an embodiment of the present invention.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

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.

It should be further understood that the term "and/or" as used in the present specification and the appended claims refers to one or any and all possible combinations of the associated listed items, and includes such combinations.

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 ]".

Example 1

Referring to fig. 1, fig. 1 is a schematic flow chart of a battery cluster balanced discharging method according to an embodiment of the invention. The embodiment of the invention provides a battery cluster balanced discharging method, wherein a battery cluster comprises at least five batteries in initial states, and the batteries in the at least five initial states are connected with each other; the method comprises the following steps:

s1, acquiring at least five initial voltages of batteries in at least five initial states of the battery cluster.

In the above solution, before the acquiring at least five initial voltages of the cells in the at least five initial states of the battery cluster, the method includes: discharging the battery clusters until the discharge value of the battery management system becomes zero, and sampling the batteries in at least five initial states. The detailed process of discharging the battery cluster until the discharge value of the battery management system becomes zero is that the maximum current discharging operation is carried out on the battery cluster until the minimum cell voltage in all batteries reaches a preset voltage value, the current downshifting is carried out to continue discharging, and when the last current is discharged and the minimum cell voltage reaches a set warning value, the discharge value limit of the battery management system is zero.

In an embodiment, voltages of the six initial states of the battery cluster are acquired, and are sequentially set to a first initial voltage, a second initial voltage, a third initial voltage, a fourth initial voltage, a fifth initial voltage, and a sixth initial voltage in order from small to large. In an embodiment, voltages of the six initial states of the battery cluster are acquired, and are sequentially set to a first initial voltage 2V, a second initial voltage 4V, a third initial voltage 6V, a fourth initial voltage 8V, a fifth initial voltage 10V, and a sixth initial voltage 12V in order from small to large.

In an embodiment, before the obtaining at least five initial voltages of the cells in the at least five initial states of the battery cluster, the method includes: the method comprises the steps of obtaining the number of batteries of at least five initial states of the battery cluster. The battery cluster is composed of at least five batteries in an initial state, if the batteries in the initial state are five, the number of the batteries is five, if the batteries in the initial state are six, the number of the batteries is six, and if the batteries in the initial state are ten, the number of the batteries is ten.

S2, judging whether the deviation degree among at least five initial voltages accords with a preset condition.

In one embodiment, it is determined whether the degree of deviation between the first initial voltage, the second initial voltage, the third initial voltage, the fourth initial voltage, the fifth initial voltage, and the sixth initial voltage satisfies both the first condition and the second condition. In one embodiment, the at least five initial voltages include an initial maximum voltage and an initial minimum voltage; the meeting of the preset conditions comprises the following steps: simultaneously satisfying the first condition and the second condition; the first condition is that a deviation value between the initial maximum voltage and the initial minimum voltage is smaller than or equal to a preset deviation threshold value; the second condition is that the variance value of at least five initial voltages is less than or equal to a preset variance threshold.

The method has the technical effects that whether the difference between the maximum value and the minimum value is overlarge or not and whether the deviation degree of mutual comparison between the voltages is overlarge or not can be measured out of at least five initial voltages, and conditions are created for engineers to reasonably select an equalization mode through adjustment of deviation threshold values and variance threshold values. In an embodiment, the initial maximum voltage is 12V, the initial minimum voltage is 2V, the deviation value between the initial maximum voltage and the initial minimum voltage is 10V, and the preset deviation threshold may be set by an engineer.

And S3, if the deviation degree between the at least five initial voltages does not meet the preset condition, performing active equalization on the battery in the at least five initial states, and then performing passive equalization on the battery in the at least five initial states to obtain the battery in the at least five equalization states.

In an embodiment, if the deviation degree between the six initial voltages does not meet the preset condition, performing active equalization on the batteries in the six initial states, and then performing passive equalization on the batteries in the six initial states to obtain the batteries in the six equalization states. In the above scheme, if the deviation degree between the at least five initial voltages accords with the preset condition, the at least five initial-state batteries are directly subjected to passive equalization to obtain at least five balanced-state batteries.

Example 2

Referring to fig. 2-5, fig. 2 is a schematic flow chart of another battery cluster balanced discharging method according to an embodiment of the present invention. The embodiment of the invention provides a battery cluster balanced discharging method, wherein a battery cluster comprises at least five batteries in initial states, and the batteries in the at least five initial states are connected with each other; the method comprises the following steps:

s101, acquiring voltages of the batteries in six initial states of the battery cluster, and sequentially setting the voltages as a first initial voltage, a second initial voltage, a third initial voltage, a fourth initial voltage, a fifth initial voltage and a sixth initial voltage in order from small to large.

In an embodiment, voltages of the six initial states of the battery cluster are acquired, and are sequentially set to a first initial voltage 2V, a second initial voltage 4V, a third initial voltage 6V, a fourth initial voltage 8V, a fifth initial voltage 10V, and a sixth initial voltage 12V in order from small to large.

S102, judging whether the deviation degree among the first initial voltage, the second initial voltage, the third initial voltage, the fourth initial voltage, the fifth initial voltage and the sixth initial voltage meets the first condition and the second condition at the same time.

Wherein the at least five initial voltages include an initial maximum voltage and an initial minimum voltage; the meeting of the preset conditions comprises the following steps: simultaneously satisfying the first condition and the second condition; the first condition is that a deviation value between the initial maximum voltage and the initial minimum voltage is smaller than or equal to a preset deviation threshold value; the second condition is that the variance value of at least five initial voltages is less than or equal to a preset variance threshold. In an embodiment, the initial maximum voltage is 12V, the initial minimum voltage is 2V, the deviation value between the initial maximum voltage and the initial minimum voltage is 10V, and the preset deviation threshold may be set by an engineer.

And S103, if the deviation degree of the six initial voltages does not meet the preset condition, performing active equalization on the batteries in the six initial states, and then performing passive equalization on the batteries in the six initial states to obtain the batteries in the six equalization states.

In the above scheme of performing active equalization on the batteries in six initial states and then performing passive equalization on the batteries in six initial states, referring to fig. 4-5, when the batteries include a target battery and other batteries, and the batteries are actively equalized and discharged, the battery management system BMS sends a control signal to control the conduction of the main switch MOS of the built-in BBU, boosts the voltage of the battery through a transformer in the BBU and controls the output current of the BBU to be always at a preset value, the energy of the target battery is output to other batteries, the battery management system sends a stop signal to the BBU after the battery outputs a period of time, the battery output current is zero, the BMU in the battery management system collects the battery voltage, the battery management system compares the voltages, and stops sending a discharge signal when the target battery voltage does not need to be discharged, and then sends a discharge signal when the target battery voltage needs to be discharged.

Referring specifically to fig. 4, the battery management system BMS of the schematic diagram has a main control MCU, and the BBU has an auxiliary MCU for controlling the on/off of the equalization, which is in an equalization off state by default. The battery management system is connected with the BBU through a CAN signal line, the battery management system is connected with the BMU through a daisy chain signal line, and the daisy chain is converted from SPI signals through a digital isolator. The battery PACK is connected with the high-voltage box through the opposite plug ports; in the active equalizing charge scheme, the BBU takes electricity from the battery cluster to charge the battery PACK, and whether the battery PACK is charged or not is controlled by the MCU of the battery management system.

Referring to fig. 5 specifically, a battery management system BMS of the schematic diagram includes a master control MCU, a PWM module in a BBU, and the battery management system is connected to the BMU through a daisy chain signal line, the daisy chain is converted from an SPI signal through a digital isolator, an IO port of an AFE chip in the BMU is connected to the PWM module in the BBU, and the battery management system controls the BMU to indirectly control the opening and closing of equalization, which is an equalization off state in default. The battery PACK is connected with the high-voltage box through the opposite plug ports; in the active equalization charging scheme, the BBU takes electricity from the battery cluster to charge the battery PACK, and whether the battery PACK is charged or not is controlled by the MCU of the battery management system.

In one embodiment, referring specifically to fig. 3, the battery cluster includes six initial state batteries, which are interconnected; the method for obtaining the six balanced-state batteries by performing active equalization and then passive equalization on the six initial-state batteries comprises the following steps:

s201, controlling the second battery to discharge until the first initial voltage of the first battery changes to the first range voltage and the second initial voltage of the second battery changes to the first range voltage.

In an embodiment, the voltages of the six batteries in the initial states are sequentially set from small to large to be a first initial voltage 2V of the first battery, a second initial voltage 4V of the second battery, a third initial voltage 6V of the third battery, a fourth initial voltage 8V of the fourth battery, a fifth initial voltage 10V of the fifth battery, and a sixth initial voltage 12V of the sixth battery.

In one embodiment, the second battery is controlled to discharge until the first initial voltage of the first battery changes to the first range voltage 2.3 + -0.2V and the second initial voltage of the second battery changes to the first range voltage 2.3 + -0.2V. At this time, the third battery is 6.3+ -0.2V, the fourth battery is 8.3+ -0.2V, the fifth battery is 10.3+ -0.2V, and the sixth battery is 12.3+ -0.2V; the data holds a fraction of a bit, and estimates, errors, or fluctuations in the process are known to those skilled in the art.

S202, controlling the third battery to discharge until the first range voltage changes to the second range voltage and the third initial voltage of the third battery changes to the second range voltage.

In one embodiment, the third battery is controlled to discharge until the first range voltage is changed to the second range voltage of 2.9 + -0.2V and the third initial voltage of the third battery is changed to the second range voltage of 2.9 + -0.2V. At this time, the fourth cell 8.9±0.2V, the fifth cell 10.9±0.2V, and the sixth cell 12.9±0.2V; the data holds a fraction of a bit, and estimates, errors, or fluctuations in the process are known to those skilled in the art.

S203, controlling the fourth battery to discharge until the second range voltage is changed to the third range voltage and the fourth initial voltage of the fourth battery is changed to the third range voltage.

In one embodiment, the fourth battery is controlled to discharge until the second range voltage is changed to the third range voltage of 3.9 + -0.2V and the fourth initial voltage of the fourth battery is changed to the third range voltage of 3.9 + -0.2V. At this time, the fifth battery 11.9±0.2V, the sixth battery 13.9±0.2V; the data holds a fraction of a bit, and estimates, errors, or fluctuations in the process are known to those skilled in the art.

S204, controlling the fifth battery to discharge until the third range voltage is changed to the fourth range voltage and the fifth initial voltage of the fifth battery is changed to the fourth range voltage.

In one embodiment, the fifth battery is controlled to discharge until the third range voltage is changed to the fourth range voltage of 5.2 + -0.2V and the fifth initial voltage of the fifth battery is changed to the fourth range voltage of 5.2 + -0.2V. At this time, the sixth battery 15.2±0.2V; the data holds a fraction of a bit, and estimates, errors, or fluctuations in the process are known to those skilled in the art.

S205, the sixth battery is controlled to discharge until the fourth range voltage is changed to the fifth range voltage and the sixth initial voltage of the sixth battery is changed to the fifth range voltage.

In one embodiment, the sixth battery is controlled to discharge until the fourth range voltage is changed to the fifth range voltage of 6.8 + -0.2V, and the sixth initial voltage of the sixth battery is changed to the fifth range voltage of 6.8 + -0.2V. At this time, the voltages from the first battery to the sixth battery are all in the range of 6.8±0.2V. The data holds a fraction of a bit, and estimates, errors, or fluctuations in the process are known to those skilled in the art.

S206, controlling the six batteries to perform passive equalization to obtain six batteries in an equalization state.

In the process, the whole battery cluster is discharged from the battery with the second low voltage value by taking the voltage value as the basis, only a small amount of batteries generate heat in the initial stage, and other batteries generate heat in sequence along with the time until all the batteries generate heat, so that the temperature rise curve of the whole battery cluster is more gentle, and the situation that the heat density in unit time is overlarge can not occur, and the method is suitable for technical scenes with low requirements on the length of time and high requirements on the heat generation amount, and has remarkable advantages compared with the prior art.

The passive equalization discharges the battery with higher voltage in a resistance discharge mode, and releases the electric quantity in a heat form, and specific embodiments of the passive equalization are known to those skilled in the art. The passive equalization implementation operation may be that the battery is discharged until the voltage of the single battery is below a certain voltage value, the battery is turned on after being turned off and kept still for one hour, the program queries an OCV-SOC table provided by a battery cell manufacturer to obtain the actual SOC of each battery cell, then the time required for equalizing the voltage of each battery cell to the lowest battery cell of the SOC is calculated by combining the size of an equalization resistor and an equalization duty ratio, finally the MOS tube of the battery cell needing to be turned on is controlled to be turned on, and the equalization MOS is turned off when the time required for turning on is equal to the calculated time.

In an embodiment, the six batteries are controlled to perform passive equalization until the deviation between the upper limit voltage value and the lower limit voltage value of the sixth range voltage does not exceed a preset percentage, and the sixth range voltage is changed to an equalization state voltage, so as to obtain the six batteries in the equalization state. In an embodiment, the six batteries are controlled to perform passive equalization until the deviation between the upper limit voltage value and the lower limit voltage value of the sixth range voltage does not exceed a preset percentage, and the sixth range voltage is changed to an equalization state voltage, so as to obtain at least five batteries in an equalization state.

In the above-mentioned process of S201-206, one of the batteries is discharged and five batteries are charged, and the voltage increment value of the five battery charging does not exceed the preset voltage range. In one embodiment, the battery includes a target battery and other batteries, wherein one target battery is discharged and five other batteries are charged, and the voltage increase value of the five other batteries is not more than a preset voltage range.

In the actual discharging process of the battery cluster, the voltage of the two batteries cannot be completely consistent due to fluctuation, and the reason for the fluctuation is as follows: because the self-discharge rate of the battery cells is inconsistent, or the self-capacity is inconsistent, or error ranges exist in the operation of sorting the battery cells when the batteries are grouped, the voltage values of the battery cells are basically inconsistent when the SOC is low, and the raised voltage values of the battery cells under the same current are inconsistent when the SOC is low, so that the voltage between the batteries is not completely consistent finally.

The inventor finds that the heat quantity in the balanced discharging process of the battery cluster is too high, and the core reason is that the heat density in unit time in the balanced discharging process of the battery cluster is too high, so that the whole battery cluster is easy to generate high temperature. The invention has the beneficial effects that the whole battery cluster is discharged from the battery with the second low voltage value based on the voltage value, only a small amount of batteries generate heat in the initial stage, and other batteries sequentially generate heat along with the time until all the batteries generate heat, so that the temperature rise curve of the whole battery cluster is more gentle, the condition of overlarge heat density in unit time can not occur, and the technical problem of overlarge heat in the balanced discharging process of the battery cluster is solved.

In the using process of the battery clusters, due to the problems of inconsistent internal resistance, inconsistent capacity, wrong battery allocation, different battery batches and the like of the battery cores, the voltages among the battery cores in the battery are inconsistent, so that the voltages among the battery clusters are inconsistent, and finally, the situation that the available capacity of the battery clusters is reduced or SOC jump occurs; the invention has the technical effects that the energy utilization efficiency can be increased, the equalization can be automatically completed without manual configuration, and the situation of SOC jump can be avoided and the customer experience can be optimized.

Example 3

Referring to fig. 6, fig. 6 is a block diagram of a battery cluster equalization system according to another embodiment of the present invention. Corresponding to the above battery cluster equalization discharging method, the present invention also provides a battery cluster equalization system 70. The battery pack balancing system 70 includes a unit for performing the above-described battery pack balancing discharge method, and specifically includes:

an initial voltage acquisition unit 71 for acquiring at least five initial voltages of the batteries of the at least five initial states of the battery cluster.

The deviation degree judging unit 72 is configured to judge whether the deviation degree between at least five initial voltages meets a preset condition.

The equalization state conversion unit 73 is configured to perform active equalization on the battery in at least five initial states and then perform passive equalization on the battery in at least five initial states if the deviation degree between the at least five initial voltages does not meet the preset condition, so as to obtain the battery in at least five equalization states.

In the using process of the battery clusters, due to the problems of inconsistent internal resistance, inconsistent capacity, wrong battery allocation, different battery batches and the like of the battery cores, the voltages among the battery cores in the battery are inconsistent, so that the voltages among the battery clusters are inconsistent, and finally, the situation that the available capacity of the battery clusters is reduced or SOC jump occurs; the battery cluster equalization system has the technical effects that firstly, the energy utilization efficiency can be increased, secondly, equalization can be automatically completed without manual configuration, thirdly, the condition of SOC jump can be avoided, and customer experience is optimized.

The battery cluster balancing system has the technical effects that the battery cluster balancing system is based on the voltage value, the whole battery cluster is discharged from the battery with the second lowest voltage value, only a small amount of batteries generate heat in the initial stage, and other batteries sequentially generate heat along with the time until all the batteries generate heat, so that the temperature rise curve of the whole battery cluster is more gentle, the condition of overlarge heat density in unit time can not occur, and the technical problem of overlarge heat in the battery cluster balancing discharging process is solved.

Those of skill in the art will appreciate that the elements and algorithm steps described in connection with the embodiments disclosed herein may be embodied as electronic hardware, computer software, or combinations of both, and to provide a clear description of the interchangeability of hardware and software, various illustrative components and steps have been described above generally in terms of functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

In the several embodiments provided by the present invention, it should be understood that the disclosed apparatus and method may be implemented in other manners. For example, the device embodiments described above are merely illustrative. For example, the division of each unit is only one logic function division, and there may be another division manner in actual implementation. For example, a unit or component may be combined or may be integrated into another system, or some features may be omitted, or not performed.

The steps in the method of the embodiment of the invention can be sequentially adjusted, combined and deleted according to actual needs. The units in the device of the embodiment of the invention can be combined, divided and deleted according to actual needs. In addition, each functional unit in the embodiments of the present invention may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit.

The integrated unit may be stored in a storage medium if implemented in the form of a software functional unit and sold or used as a stand-alone product. Based on such understanding, the technical solution of the present invention is essentially or a part contributing to the prior art, or all or part of the technical solution may be embodied in the form of a software product stored in a storage medium, comprising several instructions for causing a computer device (which may be a personal computer, a terminal, a network device, etc.) to perform all or part of the steps of the method according to the embodiments of the present invention.

In the foregoing embodiments, the descriptions of the embodiments are focused on, and for those portions of one embodiment that are not described in detail, reference may be made to the related descriptions of other embodiments.

It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention also include such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

While the invention has been described with reference to certain preferred embodiments, it will be understood by those skilled in the art that various changes and substitutions of equivalents may be made and equivalents will be apparent to those skilled in the art without departing from the scope of the invention. Therefore, the protection scope of the invention is subject to the protection scope of the claims.

Claims

1. A battery cluster balanced discharge method, characterized in that the battery cluster comprises at least five batteries in initial states, and the batteries in the at least five initial states are connected with each other; the method comprises the following steps:

s1, acquiring at least five initial voltages of batteries in at least five initial states of the battery cluster;

s2, judging whether the deviation degree among at least five initial voltages accords with a preset condition;

2. The battery cluster balanced discharge method according to claim 1, further comprising:

and if the deviation degree between the at least five initial voltages accords with the preset condition, directly carrying out passive equalization on the batteries in the at least five initial states to obtain the batteries in the at least five equalization states.

3. The battery cluster balanced discharge method according to claim 1, wherein at least five initial voltages include an initial maximum voltage and an initial minimum voltage; the meeting of the preset conditions comprises the following steps: simultaneously satisfying the first condition and the second condition; the first condition is that a deviation value between the initial maximum voltage and the initial minimum voltage is smaller than or equal to a preset deviation threshold value; the second condition is that the variance value of at least five initial voltages is less than or equal to a preset variance threshold.

4. The battery cluster balanced discharge method according to claim 1, wherein the battery cluster includes six initial state batteries; the acquiring at least five initial voltages of the batteries in at least five initial states of the battery cluster includes:

the voltages of the batteries in the six initial states of the battery cluster are acquired, and the voltages are sequentially set to be a first initial voltage, a second initial voltage, a third initial voltage, a fourth initial voltage, a fifth initial voltage and a sixth initial voltage from small to large.

5. The battery cluster balanced discharge method according to claim 4, wherein the determining whether the degree of deviation between at least five initial voltages meets a preset condition comprises:

and judging whether the deviation degree among the first initial voltage, the second initial voltage, the third initial voltage, the fourth initial voltage, the fifth initial voltage and the sixth initial voltage meets the first condition and the second condition at the same time.

6. The method for balanced discharging a battery cluster according to claim 5, wherein if the degree of deviation between the at least five initial voltages does not meet a preset condition, performing active equalization on the at least five initial-state batteries and then performing passive equalization on the at least five initial-state batteries to obtain at least five balanced-state batteries, comprising:

and if the deviation degree of the six initial voltages does not meet the preset condition, performing active equalization on the batteries in the six initial states, and then performing passive equalization on the batteries in the six initial states to obtain the batteries in the six equalization states.

7. The method for balanced discharging of a battery cluster according to claim 6, wherein the performing active equalization on the six batteries in the initial state and then performing passive equalization on the batteries in the initial state to obtain the six batteries in the balanced state comprises:

controlling the second battery to discharge until the first initial voltage of the first battery changes to a first range voltage and the second initial voltage of the second battery changes to the first range voltage;

controlling the third battery to discharge until the first range voltage is changed to the second range voltage and the third initial voltage of the third battery is changed to the second range voltage;

controlling the fourth battery to discharge until the second range voltage is changed to the third range voltage and the fourth initial voltage of the fourth battery is changed to the third range voltage;

controlling the fifth battery to discharge until the third range voltage is changed to the fourth range voltage and the fifth initial voltage of the fifth battery is changed to the fourth range voltage;

controlling the discharge of the sixth battery until the fourth range voltage is changed to the fifth range voltage and the sixth initial voltage of the sixth battery is changed to the fifth range voltage;

and controlling the six batteries to perform passive equalization to obtain the batteries in six equalization states.

8. The battery cluster balanced discharge method according to claim 7, wherein: and in the process from controlling the second battery to controlling the sixth battery to discharge, one battery discharges and five batteries charge, and the voltage increment value of the five battery charges does not exceed the preset voltage range.

9. The battery cluster balanced discharge method according to claim 1, characterized in that before the obtaining at least five initial voltages of the batteries of at least five initial states of the battery cluster, it comprises:

discharging the battery clusters until the discharge value of the battery management system becomes zero, and sampling the batteries in at least five initial states.

10. A battery pack balancing system, characterized in that it comprises means for performing the method according to any of claims 1-9.