A kind of new energy car battery management systemTechnical field
The present invention relates to battery management system technical field, specially a kind of new energy car battery management system.
Background technique
The core key of conventional fuel oil automobile be unable to do without " three-major-items " being commonly called as: engine, chassis and gearbox andAlso there are " three-major-items " being commonly called as on New-energy electric vehicle: battery, motor and automatically controlled, since New-energy electric vehicle is in global modelIt is still newer industry in enclosing, the starting difference of every industry or trade is simultaneously little, this also allows Chinese Enterprises to be sent out within this 1886 in automobileHave the condition played a decisive match with overseas enterprise on bright multipurpose power-driven tool so far.New-energy electric vehicle " threeInner automatically controlled, i.e., the commonly referred to as battery management system BMS in the industry of big part ".
New-energy electric vehicle and the maximum difference of conventional fuel oil automobile are to use power battery as power drive, and conductIt is connected the important tie of battery pack, Full Vehicle System and motor, the importance of battery management system BMS is self-evident, is permitted both at home and abroadMore new energy vehicle enterprises all treat the battery management system technology most crucial as enterprise.
The main operational principle of BMS can be concluded simply are as follows: and data acquisition circuit acquires battery status information data first, thenData processing and analysis are carried out by electronic control unit (ECU), then based on the analysis results to the related function module in systemControl instruction is issued, and outwardly transmits information.Based on the above principles, U.S.'s University of Toledo proposes a typical BMS baseThis structure.This typical system simplifies BMS in the balanced device for being divided into charge level between 1 ECU and 1 balancing battery(EQU) two large divisions.Wherein the task of ECU is mainly made of 4 functions: data acquisition, data processing, data transmission and controlSystem.ECU also controls the cell maintenance devices such as balanced device, onboard charger.
The BMS system of Ajou university, South Korea and the exploitation of advanced engineering research institute adds heat management system, safety device, chargingIt system and writes to each other with PC machine.In addition also increase and write to each other with motor controller, realize that energy brake is fed backAnd maximum power control.
The centralized BMS structure of electric car (No. EV23) use of Hunan University's research and development.The BMS system biggest advantageIt is the safety that the reliability and system of data acquisition are improved using voltage disconnecting switch matrix.The number of its internal a plurality of isolationAnd analog signal I/O channel not only can be according to requiring flexibly to use, but also effectively enhances the anti-interference ability of system.
Foreign countries are carrying out the research of the BMS based on Smart battery module (SBM) now, i.e., are packed into 1 in 1 battery moduleA microcontroller simultaneously integrated interlock circuit, is then encapsulated into an entirety, multiple Smart battery modules again with 1 main control moduleIt is connected, is subject to other ancillary equipments, just constitutes 1 management system based on intelligent battery.The BMS is successfully realized to each batteryBattery capacity is balanced in the status monitoring of module, module and the functions such as battery protection.Army's electricity consumption of Micron company, U.S. exploitationWhat motor-car BMS was used is exactly this structure.
Comprehensive research work both domestic and external, designed BMS for electric vehicle generally comprises following functions composition portion at presentPoint: data acquisition, the estimation of residual capacity (SOC), electrical control (charge and discharge control, Balance route etc.), heat management, bursting tubeReason and data communication.
In BMS, collected data are that the basis rationally effectively managed and controlled is made to battery.Therefore, dataPrecision, sample frequency and data filtering are with regard to extremely important.In view of voltage, electric current, temperature dynamic change characterization, sample frequency1 time/s should be usually not less than.The security requirement of lithium ion battery is high, to voltage-sensitive, so each monomer electricity must be acquiredThe voltage in pond monitors the temperature of each battery.Nickel-metal hydride battery and lead-acid battery require not the acquisition precision of voltage and temperatureIt is high as lithium ion battery, it is sometimes the structure for simplifying BMS, voltage and temperature is acquired in pairs or in groups.
The determination of battery remaining power (SOC) is the key points and difficulties in BMS.Since batteries of electric automobile is in use processThe nonlinearity of middle performance makes accurately to estimate that SOC has great difficulty.The basic evaluation method of traditional SOC has open-circuit voltageMethod, internal resistance method and ampere-hour method etc..Many New Algorithms to battery SOC are developed in recent years and in succession, such as fuzzy logic is calculatedMethod model, adaptive neural network fuzzy inference model, Kalman Filter Estimation model algorithm and linear model method and impedance spectraMethod etc..
Open circuit voltage method is suitable for the battery SOC under stable testing state, unsuitable independent during electric automobile during travelingIt uses.Open circuit voltage method is typically used as the supplement of other algorithms.Internal resistance method is the connection between internal resistance and SOC according to batterySystem is to predict SOC.But the internal resistance of battery is influenced by various factors, and for measurement result vulnerable to interference, confidence level is not high.Again plusUpper this method is more complicated, computationally intensive therefore relatively difficult in practical applications.Ampere-hour method passes through the side to current integrationThe energy of energy or input battery that method record is exported from battery, further according to the starting SOC state of charge and discharge, so that it may withCalculate the SOC of battery.This method is most direct and clear, and simple and easy, has degree of precision in a short time, but longThere is biggish accumulated error when time service.
In practical application, ampere-hour method is most common method, and is often applied in combination with other methods, such as ampere-hour internal resistanceMethod, ampere-hour-Peukert equation method, ampere-hour-open circuit voltage method.These combinational algorithms are usually than using ampere-hour method precision more merelyHeight, various intelligent algorithms and New Algorithm due to be not also it is very mature, some complicated algorithms are difficult to realize on SCM system,See so being not much in practical applications, but this is the direction of future development.
For more acurrate estimation SOC, also need to consider that temperature-compensating, self discharge and aging to battery etc. are more in the algorithmAspect factor.Such as the researcher of Ajou university, South Korea and advanced engineering research institute in the estimation of nickel-metal hydride battery SOC to consideringThe actually available capacity (the considerations of containing to temperature) of battery, the influence of self-discharge rate and cell degradation to capacity, it is proposed thatSOC calculation formula are as follows:
SOC (%)=100%x (rated capacity+volume compensation factor+self discharge effect+aging effect-discharge capacity+charge volume)/Rated capacity.
Its SOC estimates accuracy within ± 3%.
The researchers such as German Jossen A think that electrical control needs the function of realizing to have: control charging process, includingEqualizaing charge;Discharge current is limited according to SOC, cell health state (SOH) and temperature.Needing to combine in electrical control is madeBattery technology and battery types set the algorithm logic that a control is charged and discharged, in this, as charge and discharge controlStandard.
In BMS, equalizaing charge is a very crucial link.Power battery is generally by more piece larger capacity monomer electricityPond is connected in series.But since there are inconsistencies between single battery, the use that this can reduce battery pack is horizontal, seriously affects electricityThe performance of electrical automobile jeopardizes the safety of electric car.Such as found in the EV23 of Hunan University's research and development, when not usingWhen equalizaing charge, battery passes through after multiple charge and discharge, and voltage difference is most between the nickel-metal hydride battery group that 10 single batteries are 1 groupAbout 2V.
There are many schemes of equalizaing charge, and when selection first has to consider complexity in circuits and equalization efficiency.Hold in the palm Lay in the U.S.Much promotes balanced device using a kind of centralization, the selectivity of non-dissipative type in its BMS.This scheme be by control afterThe switching of appliance network to carry out selected single battery equalizaing charge, and hardware device is balanced simpler than independent, but efficiencyIt is relatively low.Beijing Institute of Technology uses a kind of battery pack balancing charge protection on the electric motor coach BFC6100EV of its research and developmentSystem schema realizes the integrated use of equalizaing charge and battery protection.
The safety problem of battery itself, especially lithium ion battery can catch fire in overcharge and even explode, therefore batteryThe safety problem used is the problem that domestic and international major motor corporation and scientific research institution currently face and must solve, it is directlyWhether influence electric car being capable of popularization and application.BMS primarily focuses on the protection to battery in secure context, and prevents high electricityThe leakage of pressure and high current, essential function has: overvoltage and excess current control, over-discharge electric control, prevent temperature it is excessively high,Battery is closed in the case where colliding.
These functions can be combined with electrical control, heat management system to complete.Many systems all specially increase batteryProtect circuit and battery protection chip.Safety management system most importantly timely and accurately grasps battery items status information,It issues alarm signal or disconnecting circuit in time when abnormality occurs, prevents the generation of contingency.
Battery has different working performances at different temperature, such as lead-acid battery, lithium ion battery and nickel-metal hydride batteryOptimum working temperature be 25~40 DEG C.The variation of 9 temperature can be such that SOC, open-circuit voltage, internal resistance and the utilisable energy of battery occursVariation, or even influence whether the service life of battery.The difference of temperature is also one of the reason of causing battery balanced problem.The U.S.The Ahmad A. Pesaran of renewable energy National Laboratory points out that the main task of heat management system has: battery work being made to existWithin the scope of appropriate temperature;Reduce the temperature difference between each battery module.It may be implemented using air condition with camion to batteryThe control of temperature, this is also the common temprature control method of electric car.
Data communication is one of important component of BMS.In BMS, data communication mode mainly uses CAN total at presentLine communication mode.In the BMS of Xiamen University and Tsinghua University's cooperative development, an inside is used between internal each moduleCAN network is linked into vehicle CAN communication network with display module there are also another CAN communication interface in communication.AndFor surmounting in the BMS in No. two fuel cell electric vehicles, internal module is total using LIN for one test of Tongji University's exploitationLine communication, the communication with vehicle then use CAN bus mode.
Can choose when using Smart battery module using communication, or by way of power carrier withMaster controller communication.This 2 kinds of communication modes can reduce the wiring of BMS, reduce the complexity in circuits inside electric car,But its reliability and anti-interference ability are not so good as CAN bus.
In new energy facilities for transport and communication, especially pure electric vehicle (Electric Vehicle, EV) system, in order to meetThe requirement of course continuation mileage and speed needs to go here and there battery pack and be applied in combination, however the series-parallel combination of a large amount of batteries makesIt is substantially reduced with the reliability and service life for necessarily leading to battery pack.
Summary of the invention
The purpose of the present invention is to provide a kind of new energy car battery management systems, to solve to mention in above-mentioned background techniqueOut the problem of.The new energy car battery management system accurately estimates the SOC state of battery pack, realizes to battery chargeThe accurate estimation of state.
To achieve the above object, the invention provides the following technical scheme:
A kind of new energy car battery management system, including battery management unit and battery control unit, the battery management listInformation is uploaded to the battery control unit communicated with for acquiring cell brick information by member, and the battery control unit connectsIt receives and communicates with the cell brick information that the battery management unit of connection uploads, and carry out SOC estimation and Balance route operation.
It further, further include charger system, the battery control unit is communicatively coupled to charger system.
It further, further include vehicle-mounted electric drive system, the battery control unit is communicatively coupled to vehicle-mounted electric drive system.
Further, the battery management unit is multiple comprising control chip, multiple acquisition chips, the acquisition corePiece is connect with control chip spi bus, and the battery control unit is one, uses main control chip MPC5744P adding system corePiece MC33908.
Further, it is connected between the battery management unit and battery control unit by CAN bus.
Further, it is connected between the battery control unit and charger system by CAN bus.
Further, it is connected between the battery control unit and vehicle-mounted electric drive system by CAN bus.
Further, it is characterised in that: the battery control unit is connected with touch screen by RS485 bus.
Compared with prior art, the beneficial effects of the present invention are:
The equivalent parameters of battery is estimated by real-time online estimation algorithm, to accurately estimate the SOC state of battery pack.It is logicalIt crosses real-time online and estimates the staking-out work for simplifying battery.So that being precisely controlled to be existing to the not so good battery state of consistencyIt is real.Real-time online estimates the battery so that after either new battery or aging, can keep degree of precision and stronger error correctionAbility.
Detailed description of the invention
Fig. 1 is a kind of new energy car battery management system schematic diagram of the invention.
Specific embodiment
Following will be combined with the drawings in the embodiments of the present invention, and technical solution in the embodiment of the present invention carries out clear, completeSite preparation description, it is clear that described embodiments are only a part of the embodiments of the present invention, instead of all the embodiments.It is based onEmbodiment in the present invention, it is obtained by those of ordinary skill in the art without making creative efforts every otherEmbodiment shall fall within the protection scope of the present invention.
In the description of the present invention, it should be noted that term " up/down end ", "inner", "outside" " front end ", " rear end ",The orientation or positional relationship of the instructions such as " both ends ", " one end ", " other end " is to be based on the orientation or positional relationship shown in the drawings, onlyIt is that for the convenience of describing the present invention and simplifying the description, rather than the device or element of indication or suggestion meaning must have specificallyOrientation is constructed and operated in a specific orientation, therefore is not considered as limiting the invention.In addition, term " first ", " theTwo " are used for descriptive purposes only and cannot be understood as indicating or suggesting relative importance.
In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, term " installation " " is setSet/be arranged with ", " socket ", " connection " etc., shall be understood in a broad sense, such as " connection ", may be a fixed connection, being also possible to canDismantling connection, or be integrally connected；It can be mechanical connection, be also possible to be electrically connected；It can be directly connected, can also pass throughIntermediary is indirectly connected, and can be the connection inside two elements.For the ordinary skill in the art, can haveBody situation understands the concrete meaning of above-mentioned term in the present invention.
Referring to Fig. 1, the present invention provides a kind of technical solution:
A kind of new energy car battery management system (BMS), mainly by battery management unit (Battery ManagementUnit, BMU) and battery control unit (Battery Control Unit, BCU) be composed.BMS is using distributed principal and subordinateStructure is made of multiple BMU and single BCU, and wherein BCU is responsible for communicating with extraneous drive system and master control system, acquisition instruction,It uploads and shows battery pack information, while BCU receives the cell brick information that each monomer BMU is uploaded, carry out SOC estimation and equilibriumControl operation.
In order to solve the problems, such as observation and the battery pack peak use rate of battery status, need using battery management system(Battery Management System, BMS) is monitored and protects to it.
As the key component of the sole provider of vehicle power battery information and battery protection and control, BMS is batteryThe guarantee and expansion of group function and performance, will not only ensure the good output performance of power battery pack, extend its cycle life, moreA kind of effective status need to be provided to monitor, indirectly control, managing and alarm mechanism, provide reference frame safely for vehicle.
The present invention:
1. using the newest hardware structure for meeting ISO26262 specification in grace intelligence Pu, main control chip MPC5744P adding system chipMC33908；
2. using AUTOSAR software architecture, enable bottom software stand-alone development synchronous with application layer software, it is all to shorten exploitationPhase, and software transportability is promoted, it lays the foundation to complete the certification of ISO26262 functional safety；
3. the equivalent parameters of battery is estimated by real-time online estimation algorithm, to accurately estimate the SOC state of battery pack.The staking-out work for simplifying battery is estimated by real-time online.So that the not so good battery state of consistency be precisely controlled to forReality.Real-time online is estimated so that battery after either new battery or aging, can keep degree of precision and stronger entangleWrong ability.
The present invention:
1. being updated based on the estimation of iterative type least mean-square error to state estimation and observability estimate, realize to battery chargeThe accurate estimation of state.
2. the adaptive Sigma Kalman particle filter remaining battery life based on data driven type Fusion Model is predictedMethod.
3. controllable type resistance equalization scheme is devised based on the battery management chip that TI company releases, it is each by detectingCell voltage controls the duty ratio of signal to export, and realizes to the separately adjustable of single battery.
The present invention:
1. realizing the accurate estimation of battery SOC；
2. realizing health status estimation, maximum allowable instantaneous (5s/30s) and continue charge-discharge electric power estimation；
3. realizing efficient equalization technique, advanced cooling mechanism, maximum can support the passive euqalizing current of 200mA；
4. realizing Technology Precision, total stagnation pressure precision that flows reaches 1%FSR.
The present invention is with the following functions:
1. realize battery safety management: have reliably overcharge/Cross prevention, overcurrent/excess temperature/low-temperature protection, multistage failure examineDisconnected protection；
2. realizing high-voltage safety management: having high-voltage relay adhesion detection, the high-voltage interlocking of high anti-interference ability detects, is advancedHigh-voltage isulation monitoring；
3. realizing voltage temperature gathering line broken string diagnostic function；
4. realizing the security mechanisms such as the circuit overcurrent of battery voltage acquisition module, short-circuit protection.
The present invention:
1. enabling the system to work normally in -40 DEG C ~ 85 DEG C higher temperature ranges；
2. realizing wider monitoring temperature range, monitoring range reaches -40 ~ 125 DEG C.
The present invention:
1. supporting charging national standard GB/T 20234-2015 and GB/T 27930-2015；
2. supporting the requirement of product function safety lifecycle management in ISO26262 international safety standard；
3. CCP is supported to demarcate agreement, UDS, OBD-ii diagnosing protocol.
It although an embodiment of the present invention has been shown and described, for the ordinary skill in the art, can be withA variety of variations, modification, replacement can be carried out to these embodiments without departing from the principles and spirit of the present invention by understandingAnd modification, the scope of the present invention is defined by the appended.