CN107346907A - A kind of battery bag maintenance system and battery bag maintaining method - Google Patents

Abstract

The invention discloses a battery pack maintenance system and method, and relates to the technical field of electric vehicles. The battery pack maintenance system includes: a charging and discharging control module for charging and discharging the battery pack; a monitoring module for monitoring the performance or overall performance of the single cells of the battery pack during charging and discharging; a diagnostic module , for judging whether the performance of the single cells of the battery pack is normal, or for judging whether the overall performance of the battery pack is normal; a maintenance module, for monitoring abnormal performance of the single cells, The battery pack provides a balance service, or provides a performance recalibration service for the battery pack when the overall performance of the battery pack is detected to be abnormal. Thereby improving the impact of battery performance degradation on the mileage and service life of the electric vehicle.

Description

A battery pack maintenance system and battery pack maintenance method

technical field

The invention relates to the technical field of electric vehicles, in particular to a battery pack maintenance system and a battery pack maintenance method.

Background technique

During the operation and use of electric vehicles, as the use time increases, the driving range of electric vehicles will decline, and the speed of decline will gradually accelerate. The main reason for this phenomenon is the attenuation of the performance of the lithium-ion battery system, the power source of electric vehicles. As the use time increases, the deviation between the battery pack performance benchmark parameters originally set by the battery management system and the actual performance parameters of the battery pack becomes larger, such as the state of charge (SOC, State of Charge) originally set by the battery management system, health The deviation between technical parameters such as state (SOH, State-of-Health) and the actual SOC and SOH of the battery pack is gradually increasing. In addition, the gradual accumulation of consistency differences within the battery system will also lead to a decrease in the performance of the battery system.

Therefore, it is desirable to have a technical solution to overcome or at least alleviate at least one of the above-mentioned drawbacks of the prior art.

Contents of the invention

An object of the present invention is to provide a battery maintenance solution for an electric vehicle to improve the impact of battery performance degradation on the mileage and service life of the electric vehicle.

In order to achieve the above object, the present invention provides a battery pack maintenance system, the battery pack maintenance system includes: a charging and discharging control module for charging and discharging the battery pack; a monitoring module for monitoring the battery pack during charging and discharging The performance or overall performance of the single cells of the battery pack is monitored; the diagnostic module is used to judge whether the performance of the single cells of the battery pack is normal, or whether the overall performance of the battery pack is normal; and the maintenance module is used to In the case of monitoring the abnormal performance of the single battery, provide balancing service for the battery pack, or provide performance recalibration for the battery pack when the overall performance of the battery pack is monitored Serve.

In one embodiment, the monitoring module includes: a performance detection unit of a single battery, configured to monitor the parameters of each single battery in the battery pack during charging and discharging; the diagnostic module includes: a unit The performance diagnosis unit of the battery is used to judge whether the parameters of each single battery in the battery pack are normal; the maintenance module includes: a balancing unit, used to determine whether the parameters of each single battery in the battery are abnormal In some cases, equalization processing is performed on the battery so that the parameters of each single battery in the battery are normal.

Wherein, the parameters of the single battery include voltage, internal resistance or capacity.

In one embodiment, the diagnosis module further includes: a performance output unit of the single battery, configured to output a battery normal indication signal when the performance diagnosis unit of the single battery determines that it is normal, and the performance of the single battery The diagnostic unit outputs a battery abnormal alarm signal when it determines that it is abnormal.

In one embodiment, the equalization unit is configured to perform equalization processing on the battery pack in an active or passive equalization manner so that the parameters of each single battery in the battery pack are normal.

In one embodiment, the monitoring module includes: a performance parameter detection unit for monitoring the actual performance parameters of the battery pack during charging and discharging; the diagnosis module includes: an overall performance diagnosis unit for judging Whether the actual performance parameters monitored by the battery pack are consistent with the benchmark performance parameters recorded by the battery management system; If the benchmark performance parameters recorded by the management system do not match, recalibrate the benchmark performance parameters of the battery recorded by the battery management system.

Wherein, the actual performance parameter and the reference performance parameter include a state of charge SOC and a state of health SOH.

In one embodiment, the diagnostic module further includes: an overall performance output unit, configured to output a battery normal indication signal when the overall performance diagnostic unit determines that it is consistent, and output a battery abnormality when the overall performance diagnostic unit determines that it is inconsistent warning signal.

In order to achieve the above object, the present invention also provides a battery pack maintenance method, the battery pack maintenance method includes: charging and discharging the battery pack of the electric vehicle; or the overall performance; judge whether the performance of the single cells of the battery pack is normal, or judge whether the overall performance of the battery pack is normal; The battery pack provides balancing services, or provides performance recalibration services for the battery pack when the overall performance of the battery pack is detected to be abnormal.

In one embodiment, the method includes: monitoring the parameters of each single battery in the battery pack during charging and discharging; judging whether the parameters of each single battery in the battery are normal; When the parameters of each single cell in the battery are abnormal, performing equalization processing on the battery so that the parameters of each single cell in the battery are normal.

In one embodiment, the method further includes: outputting a battery normal indication signal when it is determined to be normal, and outputting a battery abnormality warning signal when it is determined to be abnormal; The parameters of each single battery in the battery pack are normal.

In one embodiment, the battery pack is balanced by adopting an active balancing method or a passive balancing method so that the parameters of each single battery in the battery pack are normal.

In one embodiment, the method includes: monitoring the actual performance parameters of the battery pack during charging and discharging; judging whether the monitored actual performance parameters of the battery pack are consistent with the benchmark performance parameters recorded by the battery management system Consistent; when the actual performance parameters monitored by the battery pack do not match the benchmark performance parameters recorded by the battery management system, recalibrate the benchmark performance parameters of the battery recorded by the battery management system.

In one embodiment, the method further includes: outputting a battery normal indication signal when it is determined to be normal, and outputting a battery abnormality warning signal when it is determined to be inconsistent; when receiving the battery abnormality warning signal, recalibrating all The benchmark performance parameters of the battery.

The present invention charges and discharges the battery pack of the electric vehicle; monitors the performance or overall performance of the single cells of the battery pack during the charging and discharging process; Balancing service, when the overall performance of the battery pack is abnormal, it provides performance recalibration service for the battery pack, so as to improve the overall performance of the battery pack due to the consistency difference of the performance of the single cells in the battery pack, or the performance of the battery pack. The impact of overall performance degradation on the driving range and service life of electric vehicles.

Description of drawings

Fig. 1 is a schematic flowchart of an embodiment of the battery pack maintenance method of the present invention.

Fig. 2 is a schematic flowchart of an application example of the battery pack maintenance method of the present invention.

Fig. 3 is a schematic structural diagram of an embodiment of the battery pack maintenance system of the present invention.

Fig. 4 is a schematic structural diagram of another embodiment of the battery pack maintenance system of the present invention.

detailed description

In the drawings, normal or similar reference numerals are used to denote normal or similar elements or elements having normal or similar functions. Embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings.

Fig. 1 is a schematic flowchart of an embodiment of the battery pack maintenance method of the present invention.

As shown in Figure 1, the battery pack maintenance method provided in this embodiment includes the following steps:

S102, charging and discharging the battery pack of the electric vehicle. For the convenience of monitoring, the electric vehicle can be charged to the initially set benchmark SOC value, such as 80C%, and then discharged.

S104, monitor the performance or overall performance of the single cells of the battery pack during the charging and discharging process. For example, the consistency of each single battery in the battery pack or the overall performance parameters such as SOC and SOH of the battery pack can be monitored.

S106, judging whether the performance of the single cells of the battery pack is normal, or judging whether the overall performance of the battery pack is normal. In this step, the abnormal performance of the single cells of the battery pack usually includes inconsistent performance of the single cells of the battery pack. The overall performance abnormality of the battery pack usually refers to the degradation of the overall performance of the battery pack.

S108. Provide balancing service for the battery pack when abnormal performance of the single cells of the battery pack is detected, or provide performance recalibration service for the battery pack when overall performance degradation of the battery pack is detected.

Some exemplary battery maintenance services are listed below.

(1) Recalibration of battery performance parameters

Monitor the actual performance parameters of the battery pack during charging and discharging; judge whether the actual performance parameters monitored by the battery pack are consistent with the benchmark performance parameters recorded by the battery management system, and output a battery normal indication signal when it is judged normal, and when it is judged abnormal When the battery abnormal alarm signal is output; when the battery abnormal alarm signal is received, the benchmark performance parameters of the battery recorded by the battery management system are recalibrated. Among them, the battery management system can be either a supporting part in the battery pack or an electric vehicle. The above-mentioned "conformity" can be understood as the fact that the actual performance parameters are considered to be consistent within the range given by the benchmark performance parameters recorded by the battery management system.

Wherein, the actual performance parameter and the benchmark performance parameter include, for example, the state of charge SOC, the state of health SOH, etc., but are not limited to the examples given. The method for determining the current actual performance parameters of the battery pack is described below by taking SOC and SOH as examples.

SOC represents the state of charge, usually expressed as a percentage. The SOC of a fully charged battery pack is 100%, and the SOC of a fully discharged battery pack is 0%. The SOC value changes with the charging and discharging of the battery pack, and can be calculated by formula (1), where Cr represents the remaining (dischargeable) power of the battery pack, and Ca represents the total available power of the battery pack:

The present invention provides two methods of calculating SOC, the coulomb counting algorithm (also known as current integration or amp-hour balance algorithm) and the open circuit voltage (OCV) measurement method.

The coulomb counting algorithm is an algorithm that tracks rapid changes in SOC. It is based on the integrated current flowing into and out of the battery pack and adopts the calculated SOC according to the actual situation. It can use the formula (2) to calculate the SOC, where Q(t ₀ ) represents the initial power of the battery pack, α represents the efficiency factor, and i( t) represents the current (positive or negative), and C _n represents the nominal capacity of the battery pack.

The above formula expresses the electric quantity of the battery in the case of an abnormal discharge rate. As the discharge rate increases, the available charge of the battery pack decreases. Another parameter that affects the available power is temperature. The hotter the temperature, the more power available. Both effects can be described using α, so the α values can be taken as a 2D array (temperature and discharge rate). According to the measured temperature and discharge rate, corresponding values are used for each integration step separately. The alpha value is largely dependent on the design and chemistry of the battery, and often varies even between different models of batteries from the same manufacturer. They have usually been tested for charge and discharge in the lab.

Open circuit voltage (OCV) measurement method, where OCV is the voltage across the battery terminals when current is drawn from the battery when there are no electrical components. There is a good linear relationship between OCV and SOC. Therefore, from a linear relationship with the measured OCV, SOC can be directly calculated.

SOH represents the state of health, which can be estimated by Equation (3), where C _aged represents the aged battery pack capacity, and C _n represents the nominal capacity referenced in each SOC calculation.

Since C _n is known, the key task of calculating SOH is to find C _aged . One possible approach is to track the maximum charge (or SOC) that can be reached over the lifetime of the battery. If, after several subsequent full charges, the maximum charge level of the battery is lower than the previously calculated aged capacity, then the aged capacity is reduced. Correspondingly, C _aged and SOH must be adjusted according to the capacity determined by Coulomb counting and OCV methods. The full state of charge is monitored when the charge current drops below a certain threshold.

Another way to determine the SOH is to track the charge and discharge cycles and take the rated value from the cycle stability point provided by the battery manufacturer. Typically, the manufacturer will ensure the total number of charge/discharge cycles at a specified temperature and depth, for example, 500 cycles at 27°C, 25% depth of discharge. Tracking the C _aged values mentioned above is supported by rating all cycles to the above numbers, and applying temperature and state-of-charge correction factors.

(2) Consistency management of batteries

As mentioned above, whether the performance of the single cells of the battery pack is normal or not mainly depends on whether the performance of the single cells of the battery pack is consistent. Usually, the inconsistent performance of the single cells of the battery pack can be regarded as abnormal performance of the single cells. The following is Judging the performance consistency of a single battery is taken as an example to illustrate the judgment method of the abnormal performance of the single battery of the battery pack and the processing method for the abnormal performance of the single battery.

Monitor the parameters of each single battery in the battery pack during charging and discharging; judge whether the parameters of each single battery in the battery are consistent, output a battery normal indication signal when the judgment is consistent, and output a battery abnormal alarm when the judgment is inconsistent signal; when receiving the battery abnormal alarm signal, the battery pack is balanced so that the parameters of each single battery in the battery pack are consistent. For example, an active equalization method or a passive equalization method may be used to perform equalization processing on the battery pack so that the parameters of each single battery in the battery pack are consistent. The "parameters of the single battery" include the voltage, internal resistance or capacity of the single battery.

Passive equalization, also known as lossy equalization, is achieved through resistance energy consumption. A resistor is connected in parallel to a single battery for shunting. Through energy consumption equalization, the excess energy in the battery with a large capacity is consumed, and the entire battery voltage is achieved. balanced.

Active equalization, also known as non-destructive equalization, is realized through energy transfer, transferring the high energy of a single cell to the low energy of a single cell, or supplementing the lowest energy of a single cell with the overall energy. For example, active balancing may be implemented in a centralized or decentralized manner. The centralized equalization method obtains energy from the entire leased battery, and then supplements power to the battery with less energy through a power conversion device. The distributed equalization method adds an energy storage component (such as a capacitor or an inductor) between adjacent batteries, and the single battery with more energy can transfer excess energy to the single battery with less energy.

The present invention charges and discharges the battery pack of the electric vehicle, monitors the overall performance of the battery pack or the performance of a single battery during the charging and discharging process, and provides the battery pack with The performance recalibration service provides a balancing service for the battery pack when the performance of the single battery is inconsistent, so as to improve the impact of battery performance degradation on the mileage and service life of the electric vehicle. Moreover, the maintenance process is simple and easy to operate, and there is no need to disassemble the battery from the electric vehicle.

Fig. 2 is a schematic flowchart of an application example of the battery pack maintenance method of the present invention.

As shown in Figure 2, the battery pack maintenance method of this application example includes the following steps:

S201, preparing electric vehicles to be maintained.

S202. Charging to an initially set reference SOC value, for example, SOC80%.

S203, monitor the performance of the battery pack, if it is detected that there is a difference between the overall performance parameter SOC/SOH and the calibration value, execute S204, if it is detected that the consistency of each single battery is not good, execute S206, and if the battery performance is normal, execute S208.

S204, use the maintenance equipment to cycle charge and discharge the battery pack, for example, cycle charge and discharge for 3 laps;

S205, test the current actual performance parameters of the battery pack such as SOC/SOH during the cycle charging and discharging process, and update the benchmark performance parameters of the battery pack recorded by the battery management system to complete recalibration of the SOC/SOH. Then execute S207.

S206. Perform equalization processing on the battery pack by adopting an active equalization method or a passive equalization method so that the parameters of each single battery in the battery pack are consistent. Then execute S207.

S207, charge and discharge the battery pack, and confirm the performance of the battery pack. Then execute S208.

S208, charging the battery pack to SOC 100%.

S209, end maintenance.

In the above application example, the charge and discharge command commands the battery pack through the charge and discharge interface of the battery pack, and other commands such as performance monitoring command the battery pack through the communication interface of the battery pack.

By charging and discharging the battery pack of the electric vehicle, the overall performance of the battery pack such as SOC/SOH or the performance of the single battery is monitored during the charging and discharging process. The package provides performance recalibration services, and provides balancing services for the battery pack when the performance of the single battery is detected to be inconsistent, thereby improving the impact of battery performance degradation on the mileage and service life of electric vehicles. Moreover, the maintenance process is simple and easy to operate, and there is no need to disassemble the battery from the electric vehicle.

Fig. 3 is a schematic structural diagram of an embodiment of the battery pack maintenance system of the present invention.

As shown in Figure 3, the battery pack maintenance system includes the following functional modules:

The charging and discharging control module 302 is used to charge and discharge the battery pack of the electric vehicle;

A monitoring module 304, configured to monitor the performance or overall performance of the single cells of the battery pack during charging and discharging;

Diagnosis module 306, used for judging whether the performance of the single cells of the battery pack is normal, or whether the overall performance of the battery pack is normal;

as well as

The maintenance module 308 provides balancing service for the battery pack when abnormal performance of the single battery is detected, and provides performance recalibration service for the battery pack when the overall performance of the battery pack is detected abnormal.

Fig. 4 is a schematic structural diagram of another embodiment of the battery pack maintenance system of the present invention.

As shown in FIG. 4 , in an embodiment of maintaining the overall performance of the battery pack, the monitoring module 304 includes: a performance parameter detection unit 4042 for monitoring the actual performance parameters of the battery pack during charging and discharging; diagnosing Module 306 includes: an overall performance diagnosis unit 4062, used to determine whether the actual performance parameters monitored by the battery pack are consistent with the benchmark performance parameters recorded by the battery management system; Output battery normal indication signal when it is determined to be consistent, and output battery abnormality alarm signal when the overall performance diagnosis unit 4062 determines that it does not match; the maintenance module 308 includes: a performance parameter calibration unit 4082, which is used to receive the battery abnormality output by the overall performance output unit 4063 When an alarm signal is detected, recalibrate the baseline performance parameters of the battery recorded by the battery management system.

Wherein, the actual performance parameter and the benchmark performance parameter include, for example, the state of charge SOC, the state of health SOH, and the like.

As shown in Figure 4, in an embodiment of maintaining the performance of the single cells of the battery pack,

The monitoring module 304 includes: a performance detection unit 4044 of a single battery, which is used to monitor the parameters of each single battery in the battery pack during charging and discharging; the diagnostic module 306 includes: a performance diagnosis unit 4064 of a single battery, used for It is used to judge whether the parameters of each single battery in the battery pack are consistent; and the performance output unit 4065 of the single battery is used to output the battery normal indication signal when the performance diagnosis unit of the single battery judges to be consistent, and the single battery When the performance diagnosis unit determines that it is inconsistent, it outputs a battery abnormal alarm signal; the maintenance module 308 includes: a balancing unit 4084, which is used to perform balancing processing on the battery pack when receiving the battery abnormal alarm signal output by the performance output unit 4065 of the single battery to make the battery The parameters of each single battery in the pack are consistent.

Wherein, the equalization unit 4084 is used to perform equalization processing on the battery pack by adopting an active equalization method or a passive equalization method so that the parameters of each single battery in the battery pack are consistent.

The battery maintenance system can be applied to the maintenance of the electric vehicle itself, and can also be applied to maintenance centers such as 4S stores.

The present invention charges and discharges the battery pack of the electric vehicle, and monitors the overall performance of the battery pack such as SOC/SOH or the performance of a single battery during the charging and discharging process. When the overall performance of the battery pack is monitored to decline, Provide performance recalibration services for battery packs, and provide balancing services for battery packs when abnormal performance of single batteries is detected, thereby improving the impact of battery performance degradation on the driving range and service life of electric vehicles. Moreover, the maintenance process is simple and easy to operate, and there is no need to disassemble the battery from the electric vehicle.

Finally, it should be pointed out that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Those skilled in the art should understand that: the technical solutions described in the foregoing embodiments can be modified, or equivalent replacements can be made to some of the technical features; these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the various aspects of the present invention. The spirit and scope of the technical solutions of the embodiments.

Claims (10)

1. A kind of 1. battery bag maintenance system, it is characterised in that including：

   Charge and discharge control module, for carrying out discharge and recharge to battery bag；

   Monitoring modular, in charge and discharge process to the performance or entirety of the cell of the battery bag Performance is monitored；

   Diagnostic module, for judging whether the performance of cell of the battery bag is normal, or judge Whether the overall performance of the battery bag is normal；

   And

   Maintenance module, in the case where monitoring the property abnormality of the cell, to the electricity Chi Bao provides balancing service, or in the case where the overall performance for monitoring the battery bag declines, to institute Battery bag offer performance is provided and re-scales service.
2. 2. battery bag maintenance system as claimed in claim 1, it is characterised in that

   The monitoring modular includes：The performance detection unit of cell, for right in charge and discharge process The parameter of each cell in the battery bag is monitored；

   The diagnostic module includes：The performance diagnogtics unit of cell, for judging in the battery bag Each cell parameter it is whether normal；

   The maintenance module includes：Balanced unit, the ginseng for each cell in the battery In the case of number exception, carrying out equilibrium treatment to the battery makes the ginseng of each cell in the battery Number is normal.
3. 3. battery bag maintenance system as claimed in claim 2, it is characterised in that

   The diagnostic module also includes：The performance output unit of cell, in the cell Performance diagnogtics unit judge it is normal when export the normal indication signal of battery, examined in the performance of the cell Disconnected unit exports battery abnormality alarming signal when judging abnormal.
4. 4. battery bag maintenance system as claimed in claim 1, it is characterised in that

   The monitoring modular includes：Performance parameter detection unit, in charge and discharge process to the electricity Chi Bao actual performance parameter is monitored；

   The diagnostic module includes：Overall performance diagnosis unit, for judging that the battery bag is monitored to Actual performance parameter whether be consistent with the reference performance parameter that battery management system records；

   The maintenance module includes：Performance parameter demarcates unit, for what is be monitored in the battery bag In the case that actual performance parameter is not consistent with the reference performance parameter that battery management system records, re-scale The reference performance parameter of the battery of battery management system record.
5. 5. battery bag maintenance system as claimed in claim 4, it is characterised in that the diagnostic module is also Including：

   Overall performance output unit, for exporting battery when the overall performance diagnosis unit judges and is consistent Normal indication signal, battery abnormality alarming letter is exported when the overall performance diagnosis unit judges not to be consistent Number.
6. A kind of 6. battery bag maintaining method, it is characterised in that including：

   Discharge and recharge is carried out to the battery bag of electric car；

   The performance or overall performance of the cell of the battery bag are monitored in charge and discharge process；

   Judge whether the performance of the cell of the battery bag is normal, or judge the whole of the battery bag Whether body performance is normal；

   In the case where monitoring the property abnormality of the cell, balanced clothes are provided the battery bag Business, or in the case where monitoring the overall performance exception of the battery bag, to battery bag offer property Service can be re-scaled.
7. 7. battery bag maintaining method as claimed in claim 6, it is characterised in that methods described includes：

   The parameter of each cell in the battery bag is monitored in charge and discharge process；

   Judge whether the parameter of each cell in the battery is normal；

   In the case of the abnormal parameters of each cell in the battery, the battery is carried out equal Weighing apparatus processing makes the parameter of each cell in the battery normal.
8. 8. battery bag maintaining method as claimed in claim 7, it is characterised in that methods described also includes：

   The normal indication signal of battery is exported when judging normal, battery abnormality alarming is exported when judging abnormal Signal；

   When receiving battery abnormality alarming signal, carrying out equilibrium treatment to the battery bag makes the battery The parameter of each cell in bag is normal.
9. 9. battery bag maintaining method as claimed in claim 6, it is characterised in that methods described includes：

   The actual performance parameter of the battery bag is monitored in charge and discharge process；

   It is reference to judge that actual performance parameter that the battery bag is monitored to records with battery management system Whether energy parameter is consistent；

   In the actual performance parameter that the battery bag is monitored to and the reference performance of battery management system record In the case that parameter is not consistent, the reference performance ginseng of the battery of battery management system record is re-scaled Number.
10. 10. battery bag maintaining method as claimed in claim 9, it is characterised in that methods described also includes：

    The normal indication signal of battery is exported when judging normal, export battery when judging not to be consistent accuses extremely Alert signal；

    When receiving battery abnormality alarming signal, the battery of battery management system record is re-scaled Reference performance parameter.