CN113419185B - Method and system for detecting monomer capacity of lithium ion power storage battery - Google Patents

Method and system for detecting monomer capacity of lithium ion power storage battery Download PDF

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Publication number
CN113419185B
CN113419185B CN202110691106.0A CN202110691106A CN113419185B CN 113419185 B CN113419185 B CN 113419185B CN 202110691106 A CN202110691106 A CN 202110691106A CN 113419185 B CN113419185 B CN 113419185B
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ion power
power storage
storage battery
lithium ion
battery
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CN113419185A (en
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傅毅
周振浩
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Shengde Southeast Fujian New Energy Technology Co ltd
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Shengde Southeast Fujian New Energy Technology Co ltd
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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
    • G01R31/385Arrangements for measuring battery or accumulator variables
    • G01R31/387Determining ampere-hour charge capacity or SoC
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
    • G01R31/378Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC] specially adapted for the type of battery or accumulator
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
    • G01R31/385Arrangements for measuring battery or accumulator variables
    • G01R31/387Determining ampere-hour charge capacity or SoC
    • G01R31/388Determining ampere-hour charge capacity or SoC involving voltage measurements

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)
  • Secondary Cells (AREA)

Abstract

The application discloses a method for detecting the monomer capacity of a lithium ion power storage battery, which comprises the following steps: processing the lithium ion power storage battery according to a first preset condition to determine the accumulated capacity of the lithium ion power storage battery, wherein the accumulated capacity is the sum of the capacities of all the single battery cores of the lithium ion power storage battery; according to a second preset condition, the lithium ion power storage battery is processed to determine the voltage consistency of the single battery core of the lithium ion power storage battery; determining a discharging soc value and a charging soc value based on a preset voltage-soc curve of the single battery cell and the voltage consistency of the single battery cell; and determining the monomer capacity of the lithium ion power storage battery according to the accumulated capacity, the discharging soc value and the charging soc value. The method is favorable for identifying and evaluating the quality of the lithium ion power storage battery, improving the accuracy of judging the quality and the safety condition of the lithium ion power storage battery and improving the safety and the usability of the new energy automobile.

Description

Method and system for detecting monomer capacity of lithium ion power storage battery
Technical Field
The application relates to the technical field of new energy, in particular to a method and a system for detecting the monomer capacity of a lithium ion power storage battery.
Background
According to statistics, in 2012 to 2017, new energy automobiles are increased from 1 ten thousand to 60 ten thousand in annual production and marketing, the critical point of which the quantity is over 1% is maintained, the critical point exceeds the first world in japan and the united states, the industry is over the lead-in period, and the new energy automobiles steadily enter the growth period. And the country has successively brought out various development planning related files, it is seen that the new energy automobile gradually becomes the important development field in the future of the automobile industry in China.
And the lithium ion power storage battery product is finally applied to the fields of new energy automobile power and energy storage. However, the development of lithium ion power batteries in the new energy automobile field faces safety challenges: on one hand, because the use method of the user is improper, the short circuit of the lithium ion power storage battery causes combustion and explosion; on the other hand, the chemical property of lithium ions of the lithium ion power storage battery is active, and under the cooperation of a graphite negative electrode, explosion and combustion are easy to occur once the high temperature occurs. The combustion and explosion of the lithium ion power storage battery in use can threaten the personal and property of the users of the new energy automobile.
Therefore, the battery capacity parameter/index of the lithium ion power storage battery of the new energy automobile is detected, the quality of the lithium ion power storage battery can be identified and evaluated, and the accuracy of judging the quality and the safety condition of the lithium ion power storage battery is improved.
Disclosure of Invention
The present application has been made in order to solve the above technical problems. The embodiment of the application provides a method and a system for detecting the single capacity of a lithium ion power storage battery.
According to one aspect of the present application, there is provided a cell capacity detection method of a lithium ion power storage battery including one or more cell, for detecting a cell capacity of a cell in the lithium ion power storage battery,
the method comprises the following steps:
processing the lithium ion power storage battery according to a first preset condition to determine the accumulated capacity of the lithium ion power storage battery, wherein the accumulated capacity is the sum of the capacities of all the single battery cores of the lithium ion power storage battery;
according to a second preset condition, the lithium ion power storage battery is processed to determine the voltage consistency of the single battery core of the lithium ion power storage battery;
determining a discharging soc value and a charging soc value based on a preset voltage-soc curve of the single battery cell and the voltage consistency of the single battery cell;
and determining the monomer capacity of the lithium ion power storage battery according to the accumulated capacity, the discharging soc value and the charging soc value.
According to another aspect of the present application, there is provided a cell capacity detection system for a lithium-ion power battery comprising more than one cell, the system being for detecting the cell capacity of a cell in the lithium-ion power battery,
the system comprises:
the accumulated capacity detection unit is used for processing the lithium ion power storage battery according to a first preset condition to determine the accumulated capacity of the lithium ion power storage battery, wherein the accumulated capacity is the sum of the capacities of all the single battery cores of the lithium ion power storage battery;
the voltage consistency detection unit is used for processing the lithium ion power storage battery according to a second preset condition to determine the voltage consistency of the single battery cells of the lithium ion power storage battery;
the soc value calculation unit is used for determining a discharging soc value and a charging soc value based on a preset voltage-soc curve of the single battery cell and the voltage consistency of the single battery cell;
and the monomer capacity determining unit is used for determining the monomer capacity of the lithium ion power storage battery according to the accumulated capacity, the discharging soc value and the charging soc value.
The embodiment provided by the application provides a method and a system for detecting battery capacity parameters/indexes of a lithium ion power storage battery of a new energy automobile, and by adopting the method and the system, the single capacity of a single battery core of the lithium ion power storage battery can be detected, so that the quality of the lithium ion power storage battery can be evaluated, the accuracy of judging the quality and the safety condition of the lithium ion power storage battery can be improved, and the safety and the usability of the new energy automobile can be improved.
Drawings
The foregoing and other objects, features and advantages of the present application will become more apparent from the following more particular description of embodiments of the present application, as illustrated in the accompanying drawings. The accompanying drawings are included to provide a further understanding of embodiments of the application and are incorporated in and constitute a part of this specification, illustrate the application and not constitute a limitation to the application. In the drawings, like reference numerals generally refer to like parts or steps.
Fig. 1 is a schematic diagram of detection connection of a lithium ion power storage battery according to an embodiment of the present application.
Fig. 2 is a schematic flow chart of a method for detecting a single capacity of a lithium ion power storage battery according to an embodiment of the present application.
Fig. 3 is a schematic structural diagram of a single-body capacity detection system of a lithium ion power storage battery according to an embodiment of the present application.
Detailed Description
Hereinafter, example embodiments according to the present application will be described in detail with reference to the accompanying drawings. It should be apparent that the described embodiments are only some of the embodiments of the present application and not all of the embodiments of the present application, and it should be understood that the present application is not limited by the example embodiments described herein.
Exemplary method
Fig. 1 is a schematic diagram of detection connection of a lithium ion power storage battery according to an embodiment of the present application.
As shown in fig. 1, a is a lithium ion power storage BATTERY, which includes a plurality of or at least one single cell, B is a BATTERY management system (BATTERY MANAGEMENT SYSTEM, BMS) (i.e., the aforementioned preset BATTERY management system), and C is a detection device (i.e., the aforementioned specific detection device). The battery management system BMS may also be referred to as a battery nurse or a battery manager, and is mainly used for intelligently managing and maintaining each battery unit, preventing the battery from being overcharged and overdischarged, prolonging the service life of the battery, and monitoring the state of the battery. In addition, after the BMS opens the function that the electric automobile discharges by utilizing the direct current charging port, the continuous output content of information such as charge/discharge state guide, maximum allowable discharge current, lowest monomer voltage, monomer lowest allowable voltage and the like is added in the charging network after the detection flow is entered, the detection equipment can safely charge/discharge the automobile through the information, the information interaction quantity of the BMS and the detection module in the direct current charging network is increased, after the detection flow is confirmed, the BMS sends information including the use statistics information of the lithium ion power storage battery, all monomer voltage information and the like in the direct current charging network, and the detection equipment calculates and outputs the result by utilizing the information and the direct current charging interaction information to the state parameters of the lithium ion power storage battery. In some embodiments, the battery management system may be disposed in a lithium-ion power storage battery, for example, in a battery box of the same box (housing) as the lithium-ion power storage battery for intelligent management of the battery; in other embodiments, in order to facilitate maintenance, detection, and other operations on the lithium-ion power storage battery, the battery management system may be externally connected, and the battery management system may be externally connected through a connection interface of the lithium-ion power storage battery, so as to implement maintenance, detection, and other operations on the lithium-ion power storage battery.
In this application embodiment, in order to promote lithium ion power battery's convenience and precision, check out test set can satisfy following requirement: 1. the lithium ion power storage battery is provided with a bidirectional isolation DC-DC module and an energy storage system with 90kWh of electric quantity at a direct current end, so that the lithium ion power storage battery can be safely fully charged and discharged; 2. the method comprises the steps of detecting equipment flow and parameter control programmable control, carrying out full Charge and fixed SOC (or SOC, without distinguishing the case, namely State of Charge, battery State of Charge and residual electric quantity) discharge on a vehicle lithium ion power storage battery according to BMS control current and voltage requirements, taking a fixed SOC value in the charging and discharging processes, outputting pulse current with fixed time length, and carrying out acquisition preparation of direct current internal resistance information; 3. the detection equipment has detection precision on direct current end current and voltage (+ -0.1%rdg.+ -. 0.1%f.s.) of the lithium ion power storage battery, and data such as output capacity, internal resistance, voltage difference and the like are calculated through collected data.
In general, the detection apparatus in the embodiment of the present application may have the following conditions: at least has a direct current charging function and a direct current discharging function; the detection precision meets the following requirements: the output current measurement error is not more than +/-0.1% FS; the output voltage measurement error is not more than +/-0.1% FS; the temperature measurement error is not more than +/-0.5 ℃; the time measurement error is not more than +/-0.1 s; insulation test equipment precision requirement: 5%.
The lithium-ion power battery is usually installed in its carrier vehicle, which is not illustrated in the figure, mainly to show the connection situation in the test and the devices or equipment involved.
On the basis of the connection, the method for detecting the single capacity of the lithium ion power storage battery is described in detail below. Fig. 2 is a schematic flow chart of a method for detecting a single capacity of a lithium ion power storage battery according to an embodiment of the present application.
As shown in fig. 2, the method for detecting the single capacity of the lithium ion power storage battery comprises the following steps:
and step 201, processing the lithium ion power storage battery according to a first preset condition to determine the accumulated capacity of the lithium ion power storage battery, wherein the accumulated capacity is the sum of the capacities of all the single battery cells of the lithium ion power storage battery.
For example, the lithium-ion power storage battery may be subjected to a discharge treatment according to a first preset discharge condition, for example, the lithium-ion power storage battery is subjected to a discharge treatment according to a discharge mode of 1C, or the lithium-ion power storage battery is discharged to a preset discharge stop condition according to a preset constraint discharge condition, where the preset discharge constraint condition and the preset stop condition are both marked when the lithium-ion power storage battery leaves the factory.
In some embodiments, the discharge process may be, for example, discharging the lithium-ion power battery through a particular detection device (i.e., detection device C shown in fig. 1): stopping discharging the lithium ion power storage battery when the specific detection equipment receives discharge termination information of a preset battery management system and/or the specific detection equipment detects that the highest voltage value and the lowest voltage value in the discharge process exceed a voltage protection range; and recording the discharge end time. The preset discharge cut-off condition is that the soc value of the lithium ion power storage battery is adjusted to be less than 30%.
After the discharging treatment is finished, the lithium ion power storage battery after the discharging treatment is further subjected to charging treatment, so that when a first preset charging condition is reached, the accumulated capacity of the lithium ion power storage battery is obtained, and the accumulated capacity is the sum of the capacities of all the single battery cores of the lithium ion power storage battery.
Further, the lithium ion power storage battery after the discharge treatment can be subjected to power-off standing treatment; and under the condition that the power-off standing treatment reaches a preset cutoff time (for example, 10 minutes, 15 minutes or 30 minutes), charging the lithium ion power storage battery to a preset charging cutoff condition according to a preset charging constraint condition, so as to obtain the accumulated capacity of the lithium ion power storage battery. The preset charging constraint condition may be a maximum allowable charging current set by the preset battery management system, that is, the lithium-ion power storage battery is charged by the maximum allowable charging current, and in some embodiments, the charging start time may be marked; the preset charge stop condition may be, for example, from a preset battery management system, that is, the preset battery management system sends out charge stop information to the detection device, so as to control the specific detection device to stop charging the lithium ion power storage battery, or the preset battery management system sends out charge stop information to the detection device, and meanwhile, when the specific detection device detects that the highest voltage value and the lowest voltage value in the discharging process exceed the voltage protection range, the specific detection device stops charging the lithium ion power storage battery. The voltage protection range can be set or marked when the lithium ion power storage battery leaves the factory, the ranges of different lithium ion power storage batteries are possibly inconsistent, the voltage protection range is also possibly inconsistent, the rice dumplings are made of glutinous rice dumplings, and the voltage protection range is known.
In this embodiment of the present application, the voltage protection range may be set in a specific detection device, where the specific detection device compares the detected voltage value with the voltage protection range in the detection process, or the voltage protection range may be set in a preset battery management system, where the specific detection device sends the detected voltage value to the preset battery management system for comparison, and if the detected voltage value exceeds the voltage protection range, the specific detection device sends the charging termination information.
In some embodiments, determining the cumulative capacity of the lithium-ion power battery may also be accomplished, for example, by:
step 1, carrying out power-off standing treatment on the lithium ion power storage battery after the discharge treatment;
step 2, under the condition that the power-off standing treatment reaches a preset cut-off time, charging the lithium ion power storage battery by using specific detection equipment;
step 3, aiming at the lithium ion power storage battery in a charging state, acquiring the charging capacity of the lithium ion power storage battery when the SOC value of a carrier vehicle of the lithium ion power storage battery is between a first threshold value and a second threshold value, wherein the first threshold value is smaller than the second threshold value, the difference value between the second threshold value and the first threshold value is more than or equal to 5%, and the value of the first threshold value and the second threshold value is between 30% and 60%;
after the charging reaches the first preset charging condition, determining and obtaining the accumulated capacity of the lithium ion power storage battery according to the following formula:
wherein X is 2 For the second threshold value, X 1 For the first threshold value, C 1 And when the first threshold value is the SOC value of the carrier vehicle of the lithium ion power storage battery and is between the first threshold value and the second threshold value, the charge capacity of the lithium ion power storage battery.
In other embodiments, determining the cumulative capacity of the lithium-ion power battery may be accomplished, for example, by:
step 1, before a first preset charging condition is reached in the process of charging the lithium ion power storage battery after discharging treatment, recording a current value of the lithium ion power storage battery at any moment;
step 2, determining the accumulated capacity of the lithium ion power storage battery according to the following formula based on the current value and the charging time of the lithium ion power storage battery at any moment:
wherein I is the current value of the lithium ion power storage battery at any moment, t is time, and C t Is the accumulated capacity of the lithium ion power storage battery.
And 202, processing the lithium ion power storage battery according to a second preset condition to determine the voltage consistency of the single battery cells of the lithium ion power storage battery.
In some embodiments, step 202 may be implemented by:
and step 1, carrying out discharge treatment on the lithium ion power storage battery according to a second preset discharge condition. This step may be referred to as the discharge process in step 201, and is not described here again for brevity.
And 2, aiming at the lithium ion power storage battery after discharge treatment, collecting discharge voltage information of all single battery cores of the lithium ion power storage battery through a preset battery management system under the condition that the lithium ion power storage battery is not discharged through a main loop, so as to determine a differential pressure value of the lithium ion power storage battery in an empty state. For example, +_v (Discharge) = Vmax (Discharge) -Vmin (Discharge).
And step 3, according to a second preset charging condition, charging the lithium ion power storage battery after discharging treatment. This step may be referred to as the discharge process in step 201, and is not described here again for brevity.
And 4, aiming at the lithium ion power storage battery after the charging treatment, collecting charging voltage information of all single battery cores of the lithium ion power storage battery through a preset battery management system under the condition that the lithium ion power storage battery is not discharged through a main loop, so as to determine a differential pressure value of the lithium ion power storage battery in a full-charge state. For example, +_v (Charge) =vmax (Charge) -Vmin (Charge).
And step 5, determining the voltage consistency of the single battery core of the lithium ion power storage battery based on the differential pressure value in the empty state and the differential pressure value in the full state. For example, the smaller the differential pressure value in the empty state and the smaller the differential pressure value in the full state, the better the voltage uniformity of the single battery cells of the lithium ion power storage battery.
And 203, determining a discharging soc value and a charging soc value based on a preset voltage-soc curve of the single battery cell and the voltage consistency of the single battery cell.
In this embodiment, the voltage-soc curve of the single cell may be input to the battery management system BMS and/or the detection apparatus; and finding out corresponding SOCd and SOCc on the voltage-soc curve by utilizing Vn (Discharge) and Vn (Charge) obtained in the monomer voltage consistency test process, and obtaining a discharging soc value and a charging soc value.
And 204, determining the monomer capacity of the lithium ion power storage battery according to the accumulated capacity, the discharging soc value and the charging soc value.
For example, based on the accumulated capacity, the discharge soc value, and the charge soc value, the following formula is used:
C t n=C t /(SOCc-SOCd),
determining the monomer capacity of each monomer cell of the lithium ion power storage battery; wherein the C t SOCc is a charge soc value, SOCd is a discharge soc value, C is the accumulated capacity of the lithium ion power storage battery t n is the monomer capacity of the monomer battery core of the lithium ion power storage battery.
In other embodiments, initial charge availability based on the lithium-ion power battery may also be provided
And determining the current actual charge available capacity retention rate of the lithium ion power storage battery according to the following formula by the capacity and the accumulated capacity of the lithium ion power storage battery:
wherein C is 0 For initial charge available capacity, C t For the accumulated capacity, η is the current actual charge available capacity retention;
and/or the number of the groups of groups,
after the discharging treatment is performed on the lithium ion power storage battery according to the first preset discharging condition, the method further comprises: determining a current discharge available capacity of the lithium-ion power storage battery;
determining the current actual discharge available capacity retention rate of the lithium ion power storage battery according to the following formula based on the initial discharge available capacity of the lithium ion power storage battery and the current discharge available capacity of the lithium ion power storage battery:
wherein C is F For initial discharge available capacity, C' F For the current discharge available capacity, eta F The available capacity retention rate is charged for the current actual. Thus, by judging the available capacity retention rate in the charge/discharge state, the life of the lithium-ion power storage battery can be further judged.
Through the embodiment, the method and the system for detecting the battery capacity parameter/index of the lithium ion power storage battery of the new energy automobile are provided, and the single capacity of the single battery core of the lithium ion power storage battery can be detected by adopting the method and the system, so that the quality of the lithium ion power storage battery can be identified and evaluated, the accuracy of judging the quality and the safety condition of the lithium ion power storage battery can be improved, and the safety and the usability of the new energy automobile can be improved.
Based on the foregoing embodiments, the following summary describes the cell capacity detection process of the lithium-ion power storage battery according to the embodiment of the invention: (the following procedures are performed in sequence, and the influence of battery temperature factors on detection is not considered, so that the lithium ion power storage battery has a liquid cooling function by default, the temperature of the battery lithium ion power storage battery can be controlled within 35 ℃, and the detected ambient temperature is room temperature plus or minus 5 ℃):
first, mode, parameter setting procedure:
a) Setting the mode as a detection mode;
b) Setting a discharge current to send an allowable value according to the BMS;
c) Setting the type of the lithium ion power storage battery as ternary lithium/lithium iron phosphate/others;
d) Setting the lowest/highest single (single cell) voltage protection of the lithium ion power storage battery;
e) Setting a system internal resistance detection pulse discharge current value;
f) Setting a single (single cell) internal resistance detection pulse discharge current value;
g) The equipment continuously records the power battery single cell voltage, total voltage, current, SOC and temperature sampling point information sent by the BMS, and saves the original data according to the BMS numbering rule.
Second, discharge process:
a) The discharge current execution strategy allows the discharge current to be maximum according to the BMS;
b) The discharge cut-off signal (preset discharge cut-off condition) is derived from BMS active stop information, meanwhile, the detection equipment monitors the highest and lowest voltage signals of the lithium ion power storage battery, and when the highest and lowest voltage signals exceed the protection voltage range, the detection equipment actively stops the discharge flow and exits the detection flow;
c) The discharge end time point is marked.
Thirdly, standing: standing requirement, standing time
a) The device stops outputting the current with a BMS discharge stop signal;
b) BMS controls to open the lithium ion power storage battery contactor;
c) And (3) counting 15min I=0, marking a time point after standing is finished, and calling the voltage information of the lithium ion power storage battery monomer at the time point.
Fourth, charging process:
a) The detection equipment and the BMS interactively enter a charging process, and the BMS attracts the contactor to prepare for charging;
b) The charging current is controlled according to the maximum allowable charging current sent by the BMS;
c) Marking a charging starting time point;
d) The charging stop signal is derived from BMS active stop information, meanwhile, the detection equipment monitors the highest and lowest voltage signals of the lithium ion power storage battery, and when the highest and lowest voltage signals exceed the protection voltage range, the detection equipment actively stops the charging process and exits the detection process;
e) In the charging process, the equipment integrates and calculates the charging capacity according to the precisely collected current, and synchronously stores one frame of data and other information per second;
f) The charging end time point is marked.
Fifth, standing process:
a) With the BMS charge suspension signal, the device stops outputting current;
b) BMS controls to open the lithium ion power storage battery contactor;
c) Counting time for 15min I=0, marking a time point (5) after standing is finished, and calling the voltage information of the power battery monomer at the time point;
d) In the standing process, calculating the target discharge capacity of the next charge-discharge process according to Cd=50% _ of system charge capacity and 73% _ of ternary lithium/73% _ of lithium iron phosphate (the specific proportion is set in advance according to the test requirement);
e) Meanwhile, the detection equipment/BMS interface displays the capacity, voltage precision, current precision, SOC precision, charging temperature rise and other result information obtained in the previous step.
Sixth, discharge process:
a) The detection equipment and the BMS alternately enter a discharging process, and the BMS attracts the contactor to prepare for discharging;
b) Performing a discharging process according to a maximum allowable discharging current transmitted by the BMS;
c) In the discharging process, the equipment integrates and records the discharging capacity according to the precisely collected current, and the discharging process is stopped when the discharging capacity reaches Cd;
d) And the detection equipment monitors the highest and lowest voltage signals of the battery, and when the highest and lowest voltage signals exceed the protection voltage range, the detection equipment actively stops the discharge flow and exits the detection flow.
Exemplary System
Fig. 3 is a schematic structural diagram of a single-body capacity detection system of a lithium ion power storage battery according to an embodiment of the present application.
As shown in fig. 3, a system for detecting the cell capacity of a lithium ion power storage battery, where the lithium ion power storage battery includes more than one cell, is used to detect the cell capacity of the cell in the lithium ion power storage battery, and may include:
the accumulated capacity detection unit 31 is configured to process the lithium ion power storage battery according to a first preset condition, so as to determine an accumulated capacity of the lithium ion power storage battery, where the accumulated capacity is a sum of capacities of all the single battery cells of the lithium ion power storage battery;
a voltage consistency detecting unit 32, configured to process the lithium ion power storage battery according to a second preset condition, so as to determine voltage consistency of the single battery cells of the lithium ion power storage battery;
a soc value calculation unit 33, configured to determine a discharging soc value and a charging soc value based on a preset voltage-soc curve of the single cell and voltage consistency of the single cell;
and a unit capacity determining unit 34 for determining the unit capacity of the lithium ion power storage battery according to the accumulated capacity, the discharging soc value and the charging soc value.
The above units may be disposed in a specific detection device, or may be partially disposed in a preset battery management system. Illustratively, the accumulated capacity detecting unit 31 may be provided in a preset battery management system, and the voltage consistency detecting unit 32, the soc value calculating unit 33, and the unit capacity determining unit 34 may be provided in a specific detecting device.
The basic principles of the present application have been described above in connection with specific embodiments, however, it should be noted that the advantages, benefits, effects, etc. mentioned in the present application are merely examples and not limiting, and these advantages, benefits, effects, etc. are not to be considered as necessarily possessed by the various embodiments of the present application. Furthermore, the specific details disclosed herein are for purposes of illustration and understanding only, and are not intended to be limiting, as the application is not intended to be limited to the details disclosed herein as such.
The block diagrams of the devices, apparatuses, devices, systems referred to in this application are only illustrative examples and are not intended to require or imply that the connections, arrangements, configurations must be made in the manner shown in the block diagrams. As will be appreciated by one of skill in the art, the devices, apparatuses, devices, systems may be connected, arranged, configured in any manner. Words such as "including," "comprising," "having," and the like are words of openness and mean "including but not limited to," and are used interchangeably therewith. The terms "or" and "as used herein refer to and are used interchangeably with the term" and/or "unless the context clearly indicates otherwise. The term "such as" as used herein refers to, and is used interchangeably with, the phrase "such as, but not limited to.
It is also noted that in the apparatus, devices and methods of the present application, the components or steps may be disassembled and/or assembled. Such decomposition and/or recombination should be considered as equivalent to the present application.
The previous description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects without departing from the scope of the application. Thus, the present application is not intended to be limited to the aspects shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
The foregoing description has been presented for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of the application to the form disclosed herein. Although a number of example aspects and embodiments have been discussed above, a person of ordinary skill in the art will recognize certain variations, modifications, alterations, additions, and subcombinations thereof.

Claims (10)

1. A method for detecting the monomer capacity of a lithium ion power storage battery comprises more than one monomer battery core, and is characterized in that the method is used for detecting the monomer capacity of the monomer battery core in the lithium ion power storage battery,
the method comprises the following steps:
processing the lithium ion power storage battery according to a first preset condition to determine the accumulated capacity of the lithium ion power storage battery, wherein the accumulated capacity is the sum of the capacities of all the single battery cores of the lithium ion power storage battery;
according to a second preset condition, the lithium ion power storage battery is processed to determine the voltage consistency of the single battery core of the lithium ion power storage battery;
determining a discharging soc value and a charging soc value based on a preset voltage-soc curve of the single battery cell and the voltage consistency of the single battery cell;
and determining according to the accumulated capacity, the discharging soc value and the charging soc value by the following formula:
C t n=C t /(SOCc-SOCd),
determining the monomer capacity of each monomer cell of the lithium ion power storage battery; wherein the C t SOCc is a charge soc value, SOCd is a discharge soc value, C is the accumulated capacity of the lithium ion power storage battery t n is the monomer capacity of the monomer battery core of the lithium ion power storage battery.
2. The method of claim 1, wherein said determining the cell capacity of the lithium-ion power storage battery from the accumulated capacity, the discharged soc value, and the charged soc value comprises:
determining a soc difference value of the charged soc value and the discharged soc value;
and determining the monomer capacity of the lithium ion power storage battery according to the accumulated capacity and the soc difference value.
3. The method of claim 1, wherein said processing said lithium-ion power battery according to a first preset condition to determine a cumulative capacity of said lithium-ion power battery, said cumulative capacity being a sum of capacities of all individual cells of said lithium-ion power battery, comprises:
according to a first preset discharging condition, discharging the lithium ion power storage battery: performing discharge treatment on the lithium ion power storage battery according to the discharge mode of 1C;
or,
discharging the lithium ion power storage battery to a preset discharge cut-off condition according to a preset constraint discharge condition, wherein the preset constraint discharge condition and the preset discharge cut-off condition are marked when the lithium ion power storage battery leaves a factory; the preset discharge cut-off condition is that the soc value of the lithium ion power storage battery is adjusted to be less than 30%;
and carrying out charging treatment on the lithium ion power storage battery after the discharging treatment so as to obtain the accumulated capacity of the lithium ion power storage battery when the first preset charging condition is reached, wherein the accumulated capacity is the sum of the capacities of all the single battery cores of the lithium ion power storage battery.
4. The method of claim 3, wherein discharging the lithium-ion power battery according to a first preset discharge condition comprises:
discharging the lithium ion power storage battery through specific detection equipment:
stopping discharging the lithium ion power storage battery when the specific detection equipment receives discharge termination information of a preset battery management system and/or the specific detection equipment detects that the highest voltage value and the lowest voltage value in the discharge process exceed a voltage protection range;
and recording the discharge end time.
5. The method of claim 3, wherein said charging the discharged lithium-ion power battery to obtain a cumulative capacity of the lithium-ion power battery when a first preset charging condition is reached, the cumulative capacity being a sum of capacities of all individual cells of the lithium-ion power battery, comprising:
performing power-off standing treatment on the lithium ion power storage battery after the discharge treatment;
under the condition that the power-off standing treatment reaches a preset cut-off time, charging the lithium ion power storage battery to a preset charging cut-off condition according to a preset charging constraint condition to obtain the accumulated capacity of the lithium ion power storage battery, wherein the accumulated capacity is the sum of the capacities of all the single battery cores of the lithium ion power storage battery; the preset cutoff time is 15 minutes or 30 minutes.
6. The method according to claim 5, wherein, in the case where the power-off rest process reaches a preset cutoff time, charging the lithium-ion power storage battery to a preset charge cutoff condition according to a preset charge constraint condition, obtaining an accumulated capacity of the lithium-ion power storage battery, the accumulated capacity being a sum of capacities of all the individual cells of the lithium-ion power storage battery, comprising:
under the condition that the power-off standing treatment reaches a preset cut-off time, charging the lithium ion power storage battery according to a maximum allowable charging current set by a preset battery management system, and marking charging starting time; wherein the preset cutoff time is 15 minutes or 30 minutes;
when a specific detection device receives charging termination information of a preset battery management system and/or the specific detection device detects that the highest voltage value and the lowest voltage value in the discharging process exceed a voltage protection range, stopping charging the lithium ion power storage battery;
and recording the charging end time.
7. The method of claim 3, wherein said charging the discharged lithium-ion power battery to obtain a cumulative capacity of the lithium-ion power battery when a first preset charging condition is reached, the cumulative capacity being a sum of capacities of all individual cells of the lithium-ion power battery, comprising:
performing power-off standing treatment on the lithium ion power storage battery after the discharge treatment;
under the condition that the power-off standing treatment reaches a preset cut-off time, charging the lithium ion power storage battery by using specific detection equipment;
acquiring the charge capacity of a lithium ion power storage battery when the SOC value of a carrier vehicle of the lithium ion power storage battery is between a first threshold value and a second threshold value aiming at the lithium ion power storage battery in a charge state, wherein the first threshold value is smaller than the second threshold value, the difference value between the second threshold value and the first threshold value is more than or equal to 5%, and the values of the first threshold value and the second threshold value are between 30% and 60%;
after the charging reaches the first preset charging condition, determining and obtaining the accumulated capacity of the lithium ion power storage battery according to the following formula:
wherein X is 2 For the second threshold value, X 1 For the first threshold value, C 1 And when the first threshold value is the SOC value of the carrier vehicle of the lithium ion power storage battery and is between the first threshold value and the second threshold value, the charge capacity of the lithium ion power storage battery.
8. The method of claim 3, wherein said charging the discharged lithium-ion power battery to obtain the cumulative capacity of the lithium-ion power battery when a first preset charging condition is reached, comprises:
recording the current value of the lithium ion power storage battery at any moment before a first preset charging condition is reached in the process of charging the lithium ion power storage battery after discharging treatment;
based on the current value and the charging time of the lithium ion power storage battery at any moment, determining the accumulated capacity of the lithium ion power storage battery according to the following formula:
wherein I is the current value of the lithium ion power storage battery at any moment, t is time, and C t Is the accumulated capacity of the lithium ion power storage battery.
9. The method of claim 1, wherein the processing of the lithium-ion power battery to determine the voltage uniformity of the individual cells of the lithium-ion power battery according to the second preset condition comprises:
discharging the lithium ion power storage battery according to a second preset discharging condition;
aiming at the lithium ion power storage battery after discharge treatment, under the condition that the lithium ion power storage battery is not discharged through a main loop, collecting discharge voltage information of all single battery cores of the lithium ion power storage battery through a preset battery management system so as to determine a differential pressure value of the lithium ion power storage battery in an empty state;
and according to a second preset charging condition, charging the lithium ion power storage battery after discharging treatment;
aiming at the lithium ion power storage battery after the charge treatment, under the condition that the lithium ion power storage battery is not discharged through a main loop, collecting charge voltage information of all single battery cores of the lithium ion power storage battery through a preset battery management system so as to determine a differential pressure value of the lithium ion power storage battery in a full-charge state;
and determining the voltage consistency of the single battery core of the lithium ion power storage battery based on the differential pressure value in the empty state and the differential pressure value in the full state.
10. A single body capacity detection system of a lithium ion power storage battery, wherein the lithium ion power storage battery comprises more than one single body cell, and is characterized in that the system is used for detecting the single body capacity of the single body cell in the lithium ion power storage battery,
the system comprises:
the accumulated capacity detection unit is used for processing the lithium ion power storage battery according to a first preset condition to determine the accumulated capacity of the lithium ion power storage battery, wherein the accumulated capacity is the sum of the capacities of all the single battery cores of the lithium ion power storage battery;
the voltage consistency detection unit is used for processing the lithium ion power storage battery according to a second preset condition to determine the voltage consistency of the single battery cells of the lithium ion power storage battery;
the soc value calculation unit is used for determining a discharging soc value and a charging soc value based on a preset voltage-soc curve of the single battery cell and the voltage consistency of the single battery cell;
and the monomer capacity determining unit is used for determining the monomer capacity of the lithium ion power storage battery according to the accumulated capacity, the discharging soc value and the charging soc value.
CN202110691106.0A 2021-06-22 2021-06-22 Method and system for detecting monomer capacity of lithium ion power storage battery Active CN113419185B (en)

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