CN111262896A - Network-connected automobile battery management system - Google Patents
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Abstract
The invention provides a network automobile battery management system, wherein a network automobile comprises an automobile battery for providing a power source for the network automobile; the internet automobile battery management system comprises a cloud server and an automobile-mounted controller located at an automobile-mounted end. Based on the internet automobile battery management system, the invention also provides an SOC and SOH combined estimation algorithm, the SOC and SOH combined estimation is calculated on the cloud server, the accuracy loss of the algorithm caused by fixed point number operation and index table look-up approximation of the vehicle-mounted controller is avoided, and the SOC and SOH combined estimation algorithm based on cloud calculation can improve the SOC estimation accuracy by 2.5-4.5%; the SOH estimation algorithm provided by the invention can reflect the direct current internal resistance of the battery, can calculate the aging state of the internal resistance of the battery under different frequency conditions in real time, represents the aging trend of the polarization characteristic of the battery, and can reflect the SOH of the battery more comprehensively.
Description
Technical Field
The invention relates to the field of electric automobiles, in particular to a battery management system of an internet automobile.
Background
In the field of electric vehicles, a power battery unit is used as a core component of the electric vehicle, and it is important to accurately know state parameters of the power battery unit in real time during the running process of the vehicle, wherein SOC determines the current working state of the battery, determines the output power of the battery, and affects SOH, and SOH generally affects estimation of SOC, output power and residual energy in a reaction manner, so estimation accuracy of SOC and SOH is a decisive index for evaluating performance of a battery management system. Wherein, SOC, State of Charge, battery State of Charge; SOH, Section Of Health in english, battery capacity, Health and performance status.
The automobile battery management system in the prior art is completely finished by depending on a vehicle-mounted terminal, but is limited by factors such as the performance of a vehicle controller and a processor and the like, such as hardware configuration level, operation speed, reliability and the like, and some high-precision algorithms are difficult to calculate in real time in vehicle-mounted control due to the fact that the high-precision algorithms involve double-precision floating point operation, inversion operation of a multi-dimensional matrix and the like. The conventional vehicle-mounted controller supports fixed point number calculation, the difference between the calculation precision and the accurate calculation result is large, and the requirement of a high-precision algorithm for a vehicle is difficult to meet.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a network-connected automobile battery management system aiming at the defects of the prior art, and solve the problems of low calculation precision and poor real-time performance of an on-board controller.
In order to achieve the purpose, the invention is realized by the following technical scheme: a battery management system of an internet automobile is used for managing power battery units of the internet automobile and comprises a vehicle-mounted end and a cloud server; the vehicle-mounted end comprises a battery management unit, a data receiving and transmitting processing unit and a vehicle-mounted controller; the battery management unit is used for acquiring basic information of the power battery unit and transmitting the basic information to the vehicle-mounted controller and the data receiving and transmitting processing unit; the data receiving and transmitting processing unit is used for sending the basic information to the cloud server and receiving data fed back to the vehicle-mounted end from the cloud server; and the cloud server obtains the state information of the power battery unit according to the basic information and transmits the state information back to the vehicle-mounted terminal.
Preferably, the battery management unit is in communication connection with the vehicle-mounted controller and the data transceiving processing unit through a CAN bus.
Preferably, the data transceiving processing unit includes a gateway controller and a Tbox, the gateway controller is connected to the CAN bus, and the Tbox is in communication connection with the gateway controller and is configured to send the basic information to the cloud server and receive data fed back from the cloud server to the vehicle-mounted terminal.
Preferably, the data receiving and sending processing unit comprises a 4G/WIFI transmission channel, the 4G/WIFI transmission channel is connected with the CAN bus, and the data receiving and sending unit sends the basic information to the cloud server through the 4G/WIFI transmission channel and receives data fed back to the vehicle-mounted end from the cloud server.
Preferably, the power battery unit comprises a plurality of battery packs, and each battery pack comprises a plurality of single batteries; the basic information comprises a voltage value of the single battery, and the temperature of the battery pack and/or a current value of the power battery unit; the state information includes the SOC and/or SOH of the unit battery.
Preferably, the cloud server obtains the SOC of the battery cell according to the basic information, and specifically includes:
SOC 1: the cloud server acquires the basic information of the single battery at the moment k, wherein the basic information comprises the serial number of the single battery, the voltage value of the single battery, the temperature of the single battery and the current value of the single battery;
SOC 2: judging whether the identification monomer is changed or not, judging whether k is 0 moment or not by the cloud server, if so, executing SOC3, otherwise, judging whether the serial numbers of the monomer batteries are changed or not at the k moment and the k-1 moment by the cloud server, if so, executing SOC3, and otherwise, executing SOC 4;
SOC 3: initializing identification parameters including internal state x of the single battery at the moment kkSum covariance Pk；
SOC 4: predicting the predicted internal state of the single battery at the moment k +1 according to the first-order equivalent circuit model
Wherein the content of the first and second substances,
wherein x iskThe internal state of the cell predicted for the moment k, ib,kCollecting the current of the single battery at the kth moment for the cloud server, CbIs the capacity, T, of the cellsIs the sending period of the cloud server data, tau is the time constant of the battery system, Ct,sIs the polarization capacitance of the single battery;
simultaneously calculating the terminal voltage V of the single battery at the moment kb,k，
Vb,k＝OCV(SOCk)-ib,k·Rs-Vts,k
The OCV is the open-circuit voltage of the single battery, and can be obtained by looking up a table through the SOC.
SOC 5: calculating an identification covariance matrix
SOC 6: updating measurement correction gain Kk+1，
Wherein
The OCV is an open-circuit voltage of the battery,
the derivative of the open circuit voltage to SOC, which is usually a known quantity, is obtained from a SOC lookup table;
SOC 7: obtaining the internal state x of the single battery at the next momentk+1，
Wherein, yk+1The voltage value of the single battery at the moment k +1, ek+1According to predicted state
Calculated battery voltage (V)b,k+1) And the actual battery voltage (y)k+1) A difference of (d);
SOC 8: updating the identification covariance matrix Pk+1，
SOC 9: judging whether the result is valid or not, wherein the SOC algorithm accumulates the accumulated error of the same single batteryWhen the internal state x of the single battery is smaller than a set threshold value, the internal state x of the single battery is consideredk+1Is active according to xk+1Obtaining the SOC of the single battery; otherwise, go to step SOC 1.
Preferably, the step SOC1 further includes the cloud server sorting the voltages of all the cells to obtain only the SOC of the maximum voltage cellmaxOr SOC of minimum voltage cellmin；
The step SOC9 further includes the cloud server obtaining SOCmaxOr SOCminThen, the cloud server sends the SOC to the cloud servermaxOr SOCminBack transmitting to the vehicle-mounted end, when the internet connected automobile is in a charging state, the vehicle-mounted end transmits the SOC to the vehicle-mounted endmaxSOC as a whole package; when the internet automobile is in a driving state, the vehicle-mounted end handle SOCminAs a whole pack SOC.
Preferably, the cloud server obtains the SOH of the single battery according to the basic information, and specifically includes:
SOH 1: the cloud server acquires the voltage V of the single battery at the moment of the single battery kb，kAnd the cell current at time kb，k；
SOH 2: the voltage and current data are sorted, the voltage and current of the battery are recorded at the sampling frequency of Fs, and finally a voltage sequence { V }is obtainedb,1,…,Vb,k,…,Vb,nAnd the current sequence Ib,1,…,Ib,k,…,Ib,nN is the number of recorded data;
SOH 3: fourier transform is carried out on the obtained voltage and the current to obtain the amplitude of the voltage and the current of the single battery at the frequency of k/n multiplied by Fs:
wherein k has a value ranging from 1 to n/2, ωN＝e(-2πi)/N；
SOH 4: judging the prerequisite condition of internal resistance calculation, and for the selected frequency Fm-m/n multiplied by Fs, if the amplitude Y of the current under the frequency isI,Fm＝abs(Xi(m)) is less than a threshold value Y0Stopping calculation, not updating the resistance value and the SOH value of the battery, jumping to SOH1, otherwise jumping to SOH 5;
SOH 5: calculating internal resistance, and calculating resistance value of battery at frequency Fm (R (m) ═ abs (X)v(m))÷abs(Xi(m)). And looking up a table to obtain the SOH value of the single battery at the moment k based on the internal resistance value R (m) of the single battery and the estimated SOC value.
Preferably, the step SOH1 further includes the cloud server sorting the voltages of all the single batteries to obtain the SOH of the single battery with the maximum voltagemaxAnd minimum voltage of SOH of the unit cellmin。
Preferably, the vehicle-mounted terminal further comprises a display unit, the display unit is communicated with the vehicle-mounted controller through a CAN bus, and the display unit is used for displaying the basic information and/or the state information.
The cloud computing-based SOC and SOH combined estimation algorithm has the advantages that the complex SOC estimation algorithm can be transplanted to the cloud server for calculation, the precision loss caused by fixed point number operation and index table look-up approximation in the controller of the algorithm is avoided, and the SOC and SOH combined estimation algorithm based on cloud computing can improve the SOC estimation precision by 2.5-4.5%; compared with the common voltage drop method, the method can reflect the direct current internal resistance of the battery, can calculate the aging state of the internal resistance of the battery under different frequency conditions in real time, represents the aging trend of the polarization characteristic of the battery, and can more comprehensively reflect the SOH of the battery.
Drawings
Fig. 1 is a system block diagram of an online automobile battery management system according to a first embodiment of the present invention;
FIG. 2 is a data transceiving model diagram of a vehicle-mounted terminal of a battery management system of a networked automobile according to the present invention;
fig. 3 is a system block diagram of an online automobile battery management system according to a second embodiment of the present invention;
fig. 4 is a schematic flow chart of an SOC estimation algorithm of an online automobile battery management system according to a third embodiment of the present invention;
FIG. 5 is a schematic flow chart of an SOH estimation algorithm of a networked automobile battery management system according to a fourth embodiment of the present invention;
wherein the reference numerals of figures 1-5 are as follows:
the method comprises the steps that an SOC 1-cloud side obtains basic information of a single battery at the time K, an SOC 2-cloud side obtains basic information of the single battery at the time K, an SOC 3-initialized identification parameter, an SOC 4-forecasts the state of the battery at the time K +1, an SOC 5-calculates an identification covariance matrix, an SOC 6-updates a correction gain, an SOC 7-forecasts the state of the battery at the time K +1, an SOC 8-updates the identification covariance matrix, an SOC 9-judges whether an estimation result is valid or not, an SOC 10-updates an on-board end, an SOH 1-cloud side obtains the basic information of the single battery at the time K, SOH 2-arranges voltage and current data, a SOH 3-voltage and current are subjected to Fourier transformation, an SOH 4-judges an internal resistance calculation advance condition, and an SOH 5.
Detailed Description
The invention aims to provide a SOC-SOH joint estimation strategy based on cloud computing, which is characterized in that battery voltage and current acquired in real time on a vehicle are uploaded to a cloud server through a vehicle-mounted controller, the SOC and SOH of a power battery unit are obtained by the cloud server through a double Kalman filtering algorithm, and a computing result is transmitted to a vehicle-mounted terminal in real time. When the difference between the SOC and the SOH calculated by the vehicle-mounted controller and the value sent back by the cloud server is large, the vehicle-mounted controller can correct the current estimated value in real time, and therefore the vehicle-mounted SOC estimation precision is improved.
In order to realize the idea, the invention provides an online automobile battery management system, which is used for managing power battery units of an online automobile, and comprises a vehicle-mounted end and a cloud server; the vehicle-mounted end comprises a battery management unit, a data receiving and transmitting processing unit and a vehicle-mounted controller; the battery management unit is used for acquiring basic information of the power battery unit and transmitting the basic information to the vehicle-mounted controller and the data receiving and transmitting processing unit; the data receiving and transmitting processing unit is used for sending the basic information to the cloud server and receiving data fed back to the vehicle-mounted end from the cloud server; the cloud server obtains state information of the power battery unit according to the basic information and transmits the state information back to the data receiving and transmitting processing unit of the vehicle-mounted end; and the data receiving and transmitting processing unit sends the data to the vehicle-mounted controller, and the vehicle-mounted controller corrects the data.
In addition, the invention also provides an SOC-SOH joint estimation algorithm by applying the internet automobile battery management system.
To make the objects, advantages and features of the present invention more apparent, a battery management system for a networked automobile according to the present invention will be described in detail with reference to fig. 1 to 5. It should be noted that, in the present application, the embodiments and features of the embodiments may be combined with each other without conflict, and the drawings are in a very simplified form and are not to be used in a precise scale, which is only used for the purpose of conveniently and clearly assisting the description of the embodiments of the present invention.
It should be noted that the terms "first," "second," and the like in the description and claims of this application and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
< example one >
As shown in fig. 1, the battery management system of the internet-connected vehicle provided by the embodiment includes a power battery unit, where the power battery unit is used for providing a power source for the internet-connected vehicle; the online automobile battery management system comprises an automobile-mounted end and a cloud server; the vehicle-mounted end comprises a battery management unit, a data receiving and transmitting processing unit and a vehicle-mounted controller, wherein the data receiving and transmitting processing unit is used for packaging the basic information before transmitting the information to the cloud server and then transmitting the basic information to the cloud server.
The data transceiving processing unit of this embodiment is a gateway controller and a Tbox.
The vehicle-mounted terminal of this embodiment still includes the CAN bus, the CAN bus be used for battery management unit with data receiving and dispatching processing unit's information transfer, battery management unit is used for gathering power battery unit's basic information, the gateway controller with vehicle-mounted controller passes through CAN bus communication, gateway controller and Tbox are used for uploading basic information and receipt come from the high in the clouds server calculates the state information that obtains.
The vehicle-mounted terminal of the embodiment further comprises a display unit, the display unit is communicated with the vehicle-mounted controller through the CAN bus, and the display unit is used for displaying the basic information and/or the state information.
The cloud server of this embodiment obtains the state information of the power battery unit according to the basic information, and transmits back to the vehicle-mounted terminal.
As shown in fig. 2, which is a data transceiving model diagram of a vehicle-mounted end of a battery management system of a networked automobile according to the present invention, the power battery unit of this embodiment includes n battery packs, each battery pack includes m single batteries, and the n battery packs are respectively a battery pack 1, a battery pack 2, a battery pack 3 … …, and a battery pack n; the battery management unit comprises a BMC control unit and n CMC control units which are in one-to-one correspondence with the battery pack, wherein the BMC control unit measures the current output information of the whole power battery unit; CMC1Measuring the voltage of each of the individual cells of the battery 1 and the temperature signal of the battery 1Information; by analogy, CMCnMeasuring the voltage of each single battery of a battery pack n and the temperature information of the battery pack n; BMC and CMCnThe control unit sends the respectively measured information to the CAN bus. The data receiving and transmitting processing unit obtains the battery information of the power battery unit from the CAN bus: and collecting the voltage of 1-m single batteries, the temperature of 1-n battery packs and the output current of the power unit, and packaging the data. The data receiving and sending unit of this embodiment is the gateway controller and Tbox, and data is transmitted to the wireless communication unit of the cloud server through the gateway controller and Tbox according to a set rate.
The basic information of this embodiment includes a voltage value of the battery cell, a temperature of the battery pack, and/or a current value of the power battery unit; the State information includes the SOC (State of Charge) and/or SOH of the unit battery.
< example two >
The difference between the online automobile battery management system provided in this embodiment and the first embodiment is that, as shown in fig. 3, the data transceiver unit of the vehicle-mounted end of this embodiment is a 4G/WIFI transmission channel, and only the difference between the online automobile battery management system and the first embodiment is described as follows, the 4G/WIFI transmission channel communicates with the vehicle-mounted controller through the CAN bus, and the 4G/WIFI transmission channel is used for uploading the basic information and receiving the state information obtained by calculation from the cloud server.
< example three >
In this embodiment, based on the system for managing the battery of the internet vehicle provided by the present invention, the SOC estimation algorithm of the single battery is implemented, as shown in fig. 4, the SOC estimation algorithm includes the following steps:
SOC 1: the cloud server acquires basic information of the single battery at the moment k: the battery management unit collects the basic information of the single battery, the basic information comprises voltage, current and temperature and is transmitted to the vehicle-mounted controller in real time, and the vehicle-mounted controller enables the basic information to pass through the data receiving and transmitting unit and then to the cloud server.
In this embodiment, further, the cloud server sorts all the collected cell voltages, and records the maximum cell voltage V of the cell at this timemaxNumber Z corresponding to maximum cell voltagemaxNumber ZmaxTemperature T of the monomerZmaxMinimum voltage of cell VminNumber Z corresponding to minimum cell voltageminNumber ZminTemperature T of the monomerZmin. The following steps describe the SOC estimation method, which is applied to any one cell in the power cell unit. In order to avoid repetitive operations, the present embodiment performs SOC estimation only for the maximum voltage cell and the minimum voltage cell.
SOC 2: judging whether the identification cell is changed or not, judging whether k is 0 moment or not by the cloud server, if so, executing SOC3, otherwise, judging whether the serial number of the cell battery is changed or not at the k moment and the k-1 moment by the cloud server, if so, executing SOC3, and otherwise, executing SOC 4.
SOC 3: initializing identification parameters including internal state x of the single battery at the moment kkSum covariance PkLet the internal state x at time kkSum covariance PkSet to a default value.
SOC 4: predicting the predicted internal state of the single battery at the moment k +1 according to the first-order equivalent circuit model
Wherein the content of the first and second substances,
the first-order equivalent circuit model, namely the battery, is formed by connecting an open-circuit voltage, an ohmic internal resistance and an RC circuit for simulating the polarization characteristic of the battery in series; given the current battery internal parameter θk＝{Cb,Rs,e-Ts/τ,Rt,s},XkThe internal state of the cell predicted for the moment k, ib,kCollecting the current of the single battery at the moment k for the cloud server, CbIs the capacity, T, of the cellsIs the sending period of the cloud server data, tau is the time constant of the battery system, Ct,sIs the polarization capacitance of the single battery;
simultaneously calculating the terminal voltage V of the single battery at the moment kb,k，
Vb,k＝OCV(SOCk)-ib,k·Rs-Vts,k
The OCV is the open-circuit voltage of the single battery, and can be obtained by looking up a table through the SOC.
SOC 5: calculating an identification covariance matrix, and calculating a prior covariance matrix of the battery system according to the battery model
SOC 6: updating measurement correction gain Kk+1，
Wherein
The OCV is an open-circuit voltage of the battery,
the value is typically known as the derivative of the open circuit voltage with respect to SOCThe amount is obtained by looking up a table according to SOC.
SOC 7: obtaining the internal state x of the single battery at the next momentk+1，
Wherein, yk+1The voltage value of the single battery at the moment k +1, ek+1According to predicted state
Calculated battery voltage (V)b,k+1) And the actual battery voltage (y)k+1) A difference of (a), at this time, xk+1Weighted by model calculations and voltage errors.
SOC 8: updating the identification covariance matrix, calculating the posterior covariance matrix at the k +1 moment according to the current calculation result,
and updating a state covariance matrix according to the calculated Kalman gain, wherein the matrix indicates the expected value of the state estimation error, and when the value is smaller than a certain threshold value, the value obtained by state estimation is considered to be credible.
SOC 9: judging whether the result is valid, and carrying out Nest state estimation on the accumulated error of the same single battery by the SOC algorithm in an accumulated way, and accumulating the estimation error in the latest Nest
When the internal state xk +1 of the single battery is smaller than a set threshold Eest, the internal state xk +1 of the single battery is considered to be an effective state, and the SOC of the single battery is obtained according to xk + 1; otherwise, go to step SOC 1.
SOC10 the vehicle-mounted terminal obtains the SOC, which is estimated based on the highest voltage cell in this embodimentSOC (1)maxAnd SOC based on lowest voltage cell estimationminTransmitting back to the vehicle-mounted terminal, and when the vehicle is in a charging state, transmitting the SOC to the vehicle-mounted terminalmaxWhen the SOC of the power battery unit is in a running state, the SOC is determinedminAs the SOC of the power cell unit. After this step is completed, the process proceeds to step SOC 1.
< example four >
In this embodiment, based on the internet-connected vehicle battery management system provided by the present invention, the SOH estimation algorithm of the single battery is implemented, as shown in fig. 5, the SOH estimation algorithm includes the following steps:
SOH 1: the cloud server acquires the voltage V of the single battery at the moment of the single battery kb，kAnd the cell current at time kb，k。
In this embodiment, the cloud server sorts all the collected cell voltages, and records the maximum cell voltage V of the cell at the time of kmaxNumber Z corresponding to maximum cell voltagemaxNumber ZmaxTemperature T of the monomerZmaxMinimum voltage of cell VminNumber Z corresponding to minimum cell voltageminNumber ZminTemperature T of the monomerZmin. Specifically, the battery SOH estimation algorithm described in the following steps is applicable to any one of the single batteries in the power battery unit. To avoid repetitive work, the present embodiment performs SOH estimation only for the maximum voltage cell and the minimum voltage cell. Defining the data received by the cloud server as the data at the moment k, and defining the estimated voltage of the single battery at the moment k as Vb,kCurrent at time k is Ib,k。
SOH 2: the voltage and current data are sorted, the voltage and current of the battery are recorded at the sampling frequency of Fs, and finally a voltage sequence { V }is obtainedb,1,…,Vb,k,…,Vb,nAnd the current sequence Ib,1,…,Ib,k,…,Ib,nAnd n is the number of recorded data.
In this embodiment, n is set to the power of 2, and the specific value is determined according to the frequency resolution and the SOH update frequency.
SOH 3: fourier transform is carried out on the obtained voltage and the current to obtain the amplitude of the voltage and the current of the single battery at the frequency of k/n multiplied by Fs:
wherein k has a value ranging from 1 to n/2, ωN＝e(-2πi)/N。
SOH 4: judging the prerequisite condition of internal resistance calculation, and for the selected frequency Fm-m/n multiplied by Fs, if the amplitude Y of the current under the frequency isI,Fm＝abs(Xi(m)) is less than a threshold value Y0The calculation is stopped, the resistance value and the SOH value of the battery are not updated, the SOH1 is jumped to, and otherwise, the SOH5 is jumped to.
Wherein, in particular, the selected frequency FmThe test on a bench is required to obtain the correlation with the cell material and the temperature, and the embodiment is a ternary lithium battery which adopts 2-5 Hz. Y is0It is generally empirically derived and its value determines the update frequency and accuracy of the SOH and needs to be derived in real-world conditions.
SOH 5: calculating the internal resistance of the battery, calculating the resistance value of the battery at the frequency Fm, R (m) abs (X)v(m))÷abs(Xi(m)). And looking up a table to obtain the SOH value of the single battery at the moment k based on the internal resistance value R (m) of the single battery and the obtained SOC value.
In this embodiment, the resistance value R (m) based on the maximum cell voltage estimationmaxAnd the obtained SOC value SOCmaxAnd (5) looking up a table to obtain the SOH value of the maximum single-voltage battery at the moment k. Similarly, resistance value R (m) based on minimum cell voltage estimationminAnd estimated SOC value SOCminAnd (4) looking up a table to obtain the SOH value of the minimum single-voltage battery at the time k, transmitting the SOH value to the vehicle-mounted terminal, and then jumping to the step SOH 1.
Obviously, the above is applicable not only to the maximum cell voltage battery and the minimum cell voltage battery, but also to each of the cell batteries.
Based on the battery management system of the networked automobile provided by the invention, obviously, the SOC-SOH joint estimation algorithm is not limited to the content provided in the invention, and a person skilled in the art can adopt other algorithms based on the control theory to realize, and the SOC-SOH joint estimation strategy also comprises a common ampere-hour integration method, an open-circuit voltage method, a weighted mixing method and some algorithms based on the control theory, including an extended kalman filter and its modified, least square method, an observer such as an H infinity and a sliding mode. The SOH estimation algorithm includes a charging Ah estimation method, an impedance matching method, an off-line test calibration method, etc., and is not described in detail herein.
Based on the SOC and SOH of the single battery obtained by the online automobile battery management system and the SOC-SOH joint estimation algorithm provided in the above embodiments, it is obvious that a person skilled in the art can obtain the SOC and SOH of the automobile battery by weighted average, maximum and minimum and other methods based on the SOC and SOH of the single battery, and the method is within the protection scope of the present invention.
In summary, the above embodiments have described in detail various configurations of a battery management system for an internet-connected vehicle, and it should be understood that the above description is only a description of the preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way, the present invention includes but is not limited to the configurations listed in the above embodiments, and those skilled in the art can take three steps according to the above embodiments, and any changes and modifications made by those skilled in the art according to the above disclosure belong to the protection scope of the claims.
Claims (10)
1. A battery management system of an internet automobile is used for managing power battery units of the internet automobile and is characterized in that,
the online automobile battery management system comprises an automobile-mounted end and a cloud server;
the vehicle-mounted end comprises a battery management unit, a data receiving and transmitting processing unit and a vehicle-mounted controller;
the battery management unit is used for acquiring basic information of the power battery unit and transmitting the basic information to the vehicle-mounted controller and the data receiving and transmitting processing unit;
the data receiving and transmitting processing unit is used for sending the basic information to the cloud server and receiving data fed back to the vehicle-mounted end from the cloud server;
and the cloud server obtains the state information of the power battery unit according to the basic information and transmits the state information back to the vehicle-mounted terminal.
2. The networked automobile battery management system according to claim 1, wherein the battery management unit is in communication connection with the onboard controller and the data transceiving processing unit through a CAN bus.
3. The vehicle-mounted-on-grid battery management system according to claim 2, wherein the data transceiving processing unit comprises a gateway controller and a Tbox, the gateway controller is connected to the CAN bus, and the Tbox is in communication connection with the gateway controller and is configured to send the basic information to the cloud server and receive data fed back from the cloud server to the vehicle-mounted terminal.
4. The networked automobile battery management system according to claim 2, wherein the data transceiving processing unit includes a 4G/WIFI transmission channel, the 4G/WIFI transmission channel is connected to the CAN bus, and the data transceiving unit transmits the basic information to the cloud server through the 4G/WIFI transmission channel and receives data fed back from the cloud server to the vehicle-mounted terminal.
5. The battery management system of claim 2, wherein the power battery unit comprises a plurality of battery packs, each battery pack comprising a plurality of single batteries;
the basic information comprises a voltage value of the single battery, and the temperature of the battery pack and/or a current value of the power battery unit;
the state information includes the SOC and/or SOH of the unit battery.
6. The system for managing the battery of the internet-connected vehicle of claim 5, wherein the cloud server obtains the SOC of the battery cell according to the basic information, and specifically comprises:
SOC 1: the cloud server acquires the basic information of the single battery at the moment k, wherein the basic information comprises the serial number of the single battery, the voltage value of the single battery, the temperature of the single battery and the current value of the single battery;
SOC 2: judging whether the identification monomer is changed or not, judging whether k is 0 moment or not by the cloud server, if so, executing SOC3, otherwise, judging whether the serial numbers of the monomer batteries are changed or not at the k moment and the k-1 moment by the cloud server, if so, executing SOC3, and otherwise, executing SOC 4;
SOC 3: initializing identification parameters including internal state x of the single battery at the moment kkSum covariance Pk；
SOC 4: predicting the predicted internal state of the single battery at the moment k +1 according to the first-order equivalent circuit model
Wherein x iskThe internal state of the cell predicted for the moment k, ib,kCollecting the current of the single battery at the moment k for the cloud server, CbIs the capacity, T, of the cellsIs the sending period of the cloud server data, tau is the time constant of the battery system, Ct,sIs the polarization capacitance of the single battery;
simultaneously calculating the terminal voltage V of the single battery at the moment kb,k，
Vb,k＝OCV(SOCk)-ib,k·Rs-Vts,k
The OCV is the open-circuit voltage of the single battery, and can be obtained by looking up a table through the SOC;
SOC 5: calculating an identification covariance matrix
Wherein the content of the first and second substances,
for the prediction of the system covariance matrix at time k, qiModel noise standard deviation, q, as current integralvModel noise standard deviation as polarization voltage;
SOC 6: updating measurement correction gain Kk+1，
Wherein
The OCV is an open-circuit voltage of the battery,
the derivative of the open circuit voltage to SOC, which is usually a known quantity, is obtained from a SOC lookup table;
SOC 7: obtaining the internal state x of the single battery at the next momentk+1，
Wherein, yk+1The voltage value of the single battery, ek at the moment of k +1+1According to predicted state
Calculated battery voltage (V)b,k+1) And the actual battery voltage (y)k+1) A difference of (d);
SOC 8: updating the identification covariance matrix Pk+1，
SOC 9: judging whether the result is valid or not, and considering that the internal state x of the single battery is the same when the accumulated error of the SOC algorithm to the same single battery is smaller than a set threshold valuek+1Is active according to xk+1Obtaining the SOC of the single battery; otherwise, go to step SOC 1.
7. The system of claim 6, wherein the step of SOC1 further comprises the cloud server sorting the voltages of all the cells to obtain the SOC of the maximum voltage cellmaxOr SOC of minimum voltage cellmin；
The step SOC9 further includes the cloud server obtaining SOCmaxOr SOCminThen, the cloud server sends the SOC to the cloud servermaxOr SOCminBack transmitting to the vehicle-mounted end, when the internet connected automobile is in a charging state, the vehicle-mounted end transmits the SOC to the vehicle-mounted endmaxSOC as a whole package; when the internet automobile is in a driving state, the vehicle-mounted end handle SOCminAs a whole pack SOC.
8. The system for managing the battery of the internet-connected vehicle of claim 5, wherein the cloud server obtains the SOH of the battery cell according to the basic information, and specifically comprises:
SOH 1: the cloud server acquiresVoltage V of the single battery at the moment kb，kAnd the cell current at time kb，k；
SOH 2: the voltage and current data are sorted, the voltage and current of the battery are recorded at the sampling frequency of Fs, and finally a voltage sequence { V }is obtainedb,1,…,Vb,k,…,Vb,nAnd the current sequence Ib,1,…,Ib,k,…,Ib,nN is the number of recorded data;
SOH 3: fourier transform is carried out on the obtained voltage and the current to obtain the amplitude of the voltage and the current of the single battery at the frequency of k/n multiplied by Fs:
wherein k has a value ranging from 1 to n/2, ωN＝e(-2πi)/N；
SOH 4: judging the prerequisite condition of internal resistance calculation, and for the selected frequency Fm-m/n multiplied by Fs, if the amplitude Y of the current under the frequency isI,Fm＝abs(Xi(m)) is less than a threshold value Y0Stopping calculation, not updating the resistance value and the SOH value of the battery, jumping to SOH1, otherwise jumping to SOH 5;
SOH 5: calculating internal resistance, and calculating resistance value of battery at frequency Fm (R (m) ═ abs (X)v(m))÷abs(Xi(m)). And looking up a table to obtain the SOH value of the single battery at the moment k based on the internal resistance value R (m) of the single battery and the estimated SOC value.
9. The system of claim 8, wherein the SOH1 further comprises the cloud server sorting the voltages of all the cells to obtain the SOH of the cell with the maximum voltagemaxAnd minimum voltage of SOH of the unit cellmin。
10. The networked automobile battery management system according to any one of claims 2 to 9, wherein the vehicle-mounted terminal further comprises a display unit, the display unit is in communication with the vehicle-mounted controller through a CAN bus, and the display unit is used for displaying the basic information and/or the state information.
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