CN106300459A - Electric vehicle lithium battery group intelligent protection device - Google Patents

Abstract

The present invention relates to a kind of lithium battery group protection system, particularly relate to a kind of based on electric vehicle lithium battery group intelligent protection device.Including microprocessor unit 1, numeral isolated location 2, battery detection unit 3, lithium battery group 4, keyboard 5, display screen 6 and WIFI serial port module 7 form.Battery detection unit 3 is connected with lithium battery group 4, is used for detecting the voltage of the cell in lithium battery group 4 and temperature and sending microprocessor unit 1 by numeral isolated location 2 after the parameter processing of detection；Keyboard 5 and microprocessor unit 1 carry out human computer conversation；Display screen 6 is connected with microprocessor unit 1, shows related information parameters；WIFI serial port module 7 is connected with microprocessor unit 1, can be checked the relevant information of lithium battery group 4 by mobile phone etc..

Description

Electric vehicle lithium battery group intelligent protection device

Technical field

The present invention relates to a kind of lithium battery group protection system, particularly relate to a kind of based on electric vehicle lithium battery group intelligent protection device.

Background technology

Along with the development of electric motor car and gradually popularizing, the main energy sources of electric motor car is lithium battery, and the lithium battery group as important offer power energy storage device is the key factor affecting vehicle performance.In electric motor car, the high-power lithium ion power battery of application is essentially all by many cell series, parallel at present.In its application process, it is relatively big that the problem that lithium dynamical battery exists is mainly the discreteness between each cell, thus has influence on safety and the service life of whole set of cells.

Extending battery life, the service efficiency improving battery is electric automobile commercialization, practical key.Due to the existence of bucket effect, the overall performance of series battery depends on the cell that in set of cells, performance is worst, in order to the energy use to series battery effectively manages, needs to monitor in real time the cell state in series battery.In the parameter characterizing battery status, the terminal voltage of battery best embodies its duty, and therefore in precise acquisition set of cells, each monomer battery voltage is particularly significant.

At present monomer battery voltage measuring method has many, mainly can be summarized as divider resistance blood pressure lowering, floating ground measurement, analog switch gating, switch matrix, operational amplifier combine the method such as the method for relay, differential mode voltage method,

Resistance blood pressure lowering this method measurement aspect, low cost, the life-span is long, but there is cumulative error, and cannot eliminate.Along with increasing of cell number, monomer battery voltage measurement error can increase along with the increase of common-mode voltage.

When using floating ground commercial measurement battery terminal voltage, window comparator meeting automatic decision this electronegative potential current is the most suitable.Scheme is often changed by scene interference due to electronegative potential, it is impossible to accurately controls electronegative potential, affects the measurement effect of whole system.

Analog switch method: the method needs large number of amplifier and precision-matched resistance, cost is high, and the dispersibility of resistance can cause measurement result dispersibility higher.

Using switch matrix to build measuring circuit, program low cost, certainty of measurement is high, however it is necessary that absolute value circuit.

Use the operational amplifier method that combines relay, temperature drift problem can be overcome, but as the method using analog switch, it is also desirable to substantial amounts of operational amplifier and relay, and relay has life problems.

Differential mode voltage method typically uses amplifier to eliminate the common-mode voltage at battery two ends, and the comparison at present of this method is many, the method be only used for number of batteries less in the case of, and there is the problem of leakage current and resistors match, battery had a certain impact.If cost will certainly be increased use substantial amounts of photoelectric relay if add people's photoelectric relay in front end, relatively costly

Find out that the protection circuit used by current electric vehicle lithium battery group the most all exists that control accuracy is not high enough, technical specification is low, can not effectively protect the features such as lithium battery group, also becomes the focus that everybody is concerned about based on above analysis.

Summary of the invention

The present invention is directed to the deficiencies in the prior art, provide a kind of based on electric vehicle lithium battery group intelligent protection device, utilize high-performance, the microprocessor of low-power consumption is as control core, use a highly integrated battery detection chip LTC6802 that Linear Techn Inc. releases as detection core, realize whole set of cells and the condition monitoring of single battery and defencive function, reach the management to electric vehicle lithium battery group, the requirement of this control is: can manage and protect each cell in set of cells, safety purpose that is that extend battery and that improve set of cells.

The present invention is for achieving the above object; adopt the following technical scheme that a kind of based on electric vehicle lithium battery group intelligent protection device; including microprocessor unit 1, numeral isolated location 2, battery detection unit 3, lithium battery group 4, keyboard 5, display screen 6 and WIFI serial port module 7 form.

Described battery detection unit 3 is connected with lithium battery group 4, is used for detecting the voltage of the cell in lithium battery group 4 and temperature and sending microprocessor unit 1 by numeral isolated location 2 after the parameter processing of detection；Keyboard 5 and microprocessor unit 1 carry out human computer conversation；Display screen 6 is connected with microprocessor unit 1, shows related information parameters；WIFI serial port module 7 is connected with microprocessor unit 1, can be checked the relevant information of lithium battery group 4 by mobile phone etc..

The invention has the beneficial effects as follows:

1, the system uses microprocessor unit; system is made to have the biggest motility; facilitate implementation various complex control; it is thus possible to easily system is carried out Function Extension and performance improvement; realize, to whole set of cells and the condition monitoring of single battery and defencive function, reaching to extend the purpose of battery；

2, the system uses highly integrated battery detection chip LTC6802 as detection core; realize whole set of cells and the condition monitoring of single battery and defencive function; reach the management to electric vehicle lithium battery group; this control can manage and protect each cell in set of cells, safety purpose that is that extend battery and that improve set of cells；

3, the system uses WIFI serial port module, by the configurator of mobile phone terminal, can conveniently check the relevant information of lithium battery group；

4, this system uses numeral isolated location, has the incomparable advantage of photoelectric isolating device at everyways such as performance, power consumption, volumes.

Accompanying drawing explanation

Fig. 1: electric vehicle lithium battery group intelligent protection device system block diagram.

Fig. 2: special battery status monitoring chip LTC6802 detects elementary diagram.

Fig. 3: special battery status monitoring chip LTC6802 internal circuit block diagram.

Fig. 4: special battery status monitoring chip LTC6802 external discharge schematic diagram.

Fig. 5: special battery status monitoring chip LTC6802 overall control block diagram.

Fig. 6: digital isolator IC2 chip AduM1411 isolator figure pinouts.

Fig. 7: WIFI serial port module connection diagram.

Fig. 8: voltage, temperature acquisition and Balance route software flow pattern.

Detailed description of the invention

Below in conjunction with the accompanying drawings the technical scheme implementation method of invention is illustrated: as shown in Figure 1; the technical scheme that this specific embodiment uses is: a kind of based on electric vehicle lithium battery group intelligent protection device; including microprocessor unit 1, numeral isolated location 2, battery detection unit 3, lithium battery group 4, keyboard 5, display screen 6 and WIFI serial port module 7 form.

Described battery detection unit 3 is connected with lithium battery group 4, is used for detecting the voltage of the cell in lithium battery group 4 and temperature and sending microprocessor unit 1 by numeral isolated location 2 after the parameter processing of detection.

Keyboard 5 and microprocessor unit 1 carry out human computer conversation.

Display screen 6 is connected with microprocessor unit 1, shows related information parameters.

WIFI serial port module 7 is connected with microprocessor unit 1, can be checked the relevant information of lithium battery group 4 by mobile phone etc..

Fig. 2 is accumulator battery detection cell circuit block diagram, in practical working situation, carrying out along with accumulator battery discharge and recharge, the voltage of accumulator battery is continually changing, between each cell, voltage also there will be difference, the discordance of this voltage also can largely effect on the performance of set of cells, it is therefore necessary to detect the voltage of each cell.The present invention invents and uses special battery status monitoring chip to detect monomer battery voltage, and the digital signal after detection is processed to reach by microprocessor be the control unit of core.The accuracy of detection of monomer battery voltage is 0.36mV.Battery pack temperature is also the important parameter affecting battery performance, and the too high or too low meeting of battery pack temperature causes the irreversible destruction of set of cells, and the present invention uses temperature sensor to detect battery case temperature, and temperature detecting precision is 1 DEG C.

In Fig. 2, IC1 is the LTC6802 using Linear company, this is a kind of special battery status monitoring chip, its built-in 1 12 ADC, 1 accurate voltage reference, 1 high voltage input multiplexer and 1 serial line interface, it is not necessary to use photo-coupler or optoisolator.Can measure up to 12 voltage of serially-connected cells, 13 ms complete all battery voltage detection, and overall measurement error is less than 0.25%, the advantage with high Electromagnetic Compatibility, low-power consumption.

LTC6802 pin function is as follows:

V+: device working power anode, chip operation power supply is provided by battery, V+be the most just connected with set of cells;

V-: power supply negative terminal, negative total with set of cells is even;

C1-C12: cell voltage input;

S1-S12: battery balanced control end;

VT1, VT2: temperature sensor inputs;

VREF:3. 075 voltage reference;

VREG: linear voltage benchmark;

TOS: chip position in series connection group selects end;

MMB: monitoring mode selects end;

WDTB: house dog exports;

GPIO1, GPIO2: general purpose I/O mouth;

VMODE: communication mode selects end;

SCKI, SDI, SDO, CSBI:SPI interface;

CSBO, SBOI, SCKO: with the SPI interface of next stage chip communication during cascade.

Voltage acquisition and equalizing sections operation principle are such that

At Fig. 2 it can be seen that the C1-C12 foot of IC1 chip LTC6802 is the input of monitoring battery cell voltage, the positive pole of cell E1-E12 is connected with C1-C12 respectively；E1-E12 is connected in series, and the positive pole of E1 is connected with the V+ of LTC6802, and the negative pole of E12 is connected with the V-of LTC6802.

At Fig. 2 it can be seen that the S1-S12 foot of IC1 chip LTC6802 is battery balanced control foot.When certain battery cell in set of cells occur overcharging, overvoltage time, S pin will discharge with to this battery cell, to ensure the consistent of each cell.Each S pin inner portions contains a N ditch MOSFET for electric discharge, for discharging battery cell.LTC6802 can use internal and outside both of which weighing apparatus mode.Each S output pin is internal to be all connected with N channel mosfet.Internal metal-oxide-semiconductor maximum conducting resistance is 20 Europe.When using internal balance, connected to battery discharge with internal MOSFET by non-essential resistance.Internal MOSFET can also be used for controlling external Equilibrium circuit.For obtaining bigger discharge current, improve discharging efficiency, generally use external Equilibrium.10K pull-up resistor within S pin makes it export can drive the gate pole of P channel mosfet in external circuit.By external series metal-oxide-semiconductor with resistance to battery discharge.LTC6802 is controlled by IC3 microprocessor LPC11C22 by opening of chip internal MOSFET with turning off, and LTC6802 chip self is uncontrollable.

Fig. 3 is LTC6802 internal circuit block diagram, and Fig. 4 is LTC6802 external discharge schematic diagram, in the drawings it can be seen that the input of each cell is respectively provided with a switch mosfet being associated, for discharging overcharge battery.The output of S pin comprises the pull-up resistor of an internal 10K, and therefore when loading upper high-impedance state (such as outside MOSFET gate circuit), S pin can use as numeral output.IC3 microprocessor LPC11C22 can read data by spi bus from LTC6802, and controls being turned on and off, to realize the equilibrium of battery battery core of MOSFET of respective battery input.

Fig. 4 is LTC6802 external discharge schematic diagram, the schematic diagram on this Tu Shi mono-tunnel, and remaining 11 tunnels are identical in this.In order to prevent the energy pressure reduction between battery input, a Zener diode DW1 can be increased in the input of each battery.These diodes, when battery contact connects, can distribute safe voltage automatically in the input of disappearance.

RC and C1 forms RC wave filter, and DW2 is in order to protect T1, and R1 is electric discharge current-limiting resistance, and power is bigger.If detecting that cell E1 voltage is beyond setting value, IC3 microprocessor LPC11C22 sends control instruction, S1 output control signal is added to the grid of MOSFET pipe T1 through resistance R4, MOSFET pipe T1 turns on, the positive electrical of cell E1 flows through R2, T1, the negative pole of R1 to E1 discharge, until the voltage of E1 reaches setting value electric discharge and stops so that the voltage of cell E1----E2 keeps consistent, here it is the principle of Balance route.

VT1 and the VT2 foot of IC1 chip LTC6802 is temperature sensor measurement input pin in fig. 2, is connected to temperature and resistance Rt1 and Rt2, Rt1 and and R13 respectively;Being connected with VREF foot after Rt2 with R14 series connection, VREF foot is 3.075V Voltage Reference output pin, and CA electric capacity is connected with VREF as bypass.

The WDTB foot of IC1 chip LTC6802 is Watch Dog Timer output pin (Low level effective) in fig. 2.IC1 chip LTC6802 comprises an internal Watch Dog Timer circuit.If the continuous 2s of SCKI pin does not has activity, the output of WDTB open-drain to be set low.WDTB pin keeps low level has saltus step to occur until monitoring SCKI pin.At the end of watchdog circuit timing, configuration register will be placed in default conditions.When power-up state, the output of S pin is closed.Therefore, when chip and the communication disruption of MPU, Watch Dog Timer provides a kind of method that can close battery discharge.After timing terminates, chip enters the standby mode of minimum power consumption.Should be noted that now to be set low by WDTB pin from outside and can not reset configuration register.WDTEN (byte CNFGO, the 7th) in configuration register allows user to close Watch Dog Timer.The default value of WDTEN is 1, and now house dog is in opening.When MMB is low level, Watch Dog Timer is closed.When reading configuration register, byte CNFG.In the 7th state that will reflect WDTB pin, and with write WDTEN position value unrelated.Therefore, if by WDTEN position write 0 closedown house dog, WDTB can now read its return value of WDTEN position be the input value of WDTN pin as universal input pin.

IC1 chip LTC6802 have standby, measure and monitor three kinds of mode of operations, standby mode is a kind of energy saver mode, and after entering standby mode, all circuit in addition to serial ports are closed;In measurement pattern, LTC6802 can measure the voltage of each battery cell and result is stored in internal memory, and measurement pattern also can monitor whether each battery cell is in overvoltage and under-voltage condition;In monitored state, chip only monitors and is in under-voltage and overvoltage condition battery cell, and the signal that SDO pin is produced by under-voltage or overvoltage for transmission, serial ports is now in closed mode.

Fig. 5 is lithium battery group intelligent protection device overall control schematic diagram, in the drawings it can be seen that 4 feet of the spi bus of IC1 chip LTC6802 are the input of SCKI: serial clock respectively；SDI: serial date transfer；SDO: serial data exports；CSBI: chip select input (Low level effective), these 4 feet pass through the SSEL0 of digital isolator IC2 chip AduM1411 and IC3 microprocessor LPC11C22 as spi bus, MISO0, MOSI0, SCK0 connection communicates, IC3 microprocessor LPC11C22 reads the voltage and Temperature numerical collected, then determine according to the voltage of each battery and need the battery of equilibrium, microprocessor LPC11C22 is by sending instruction, IC1 chip LTC6802 corresponding registers is allowed to start or to close equilibrium, send foot by voltage by the data of IC3 microprocessor serial bus simultaneously, temperature data and equilibrium state are attached communication by WIFI serial port module.

At Fig. 5 it can be seen that its 3,4,5,6 feet be that input pin CSP1, SDO, SDI, SCK1 with IC1 chip LTC6802 respectively of IC2 digital isolator chip ADuM 1411 connects, 11,12,13,14 feet of IC2 digital isolator chip ADuM 1411 are that output pin connects with IC3 microprocessor LPC11C22 SSEL0, MISO0, MOSI0, SCK0 foot respectively, can examine and have a magnetic coupling isolation between the input of each road and output from figure.

Fig. 6 is the pinouts of IC2 digital isolator chip ADuM 1411, and ADuM 1411 is that ADI company releases universal four-way digital isolator based on its patent iCoupler magnetic coupling isolation technology.Have employed the transformer technology of high-speed cmos technique and chip-scale, have the incomparable advantage of photoelectric isolating device at everyways such as performance, power consumption, volumes.

Fig. 7 is WIFI serial port module operation principle block diagram of the present invention, and WiFi serial port module is also called embedded WiFi serial port module, is embedded into the WiFi serial port module of ICP/IP protocol.Its hardware constitutes and is mainly made up of an embedded single-chip microcomputer and WiFi module, and single-chip microcomputer bare machine to be realized driver and ICP/IP protocol, WiFi module then must complete the wireless receiving and dispatching of data.Embedded WiFi module externally provides UART serial ports or SPI interface, thus can be connected by serial ports or SPI interface and external microprocessor, allows equipment easily access Internet network.

WiFi serial port module IC4 selects TLN13U06WIFI, stops long-pending little, low in energy consumption.This module uses asynchronous receiving-transmitting transmitter (UART) interface, built-in lEEE802. 11 protocol stack and ' I'CP/IP protocol stack, it is possible to realize user's serial ports to the conversion between wireless network.

WiFi serial port module IC4 TLN13U06WIFI is connected the simplest with microprocessor IC3 on hardware, 1 foot of TLN13U06WIFI is connected with the CTS foot of microprocessor IC3, CTS(Clear To Send) allow to send: for input signal, being produced by TLN13U06WIFI chip, notice microprocessor can transmit data.

2 feet of WiFi serial port module IC4 TLN13U06WIFI are connected with the RTS foot of microprocessor IC3, RTS(Request To Send) request transmission: for output signal, microprocessor IC100 producing, notification module can send data.

6 feet of WiFi serial port module IC4 TLN13U06WIFI are connected with the TX end of microprocessor IC3, for serial data transmission.

7 feet of WiFi serial port module IC4 TLN13U06WIFI are connected with the RX end of microprocessor IC3, receive for serial data.

Actual practicality first passes through the configurator of mobile phone terminal, the title (SSID) of the router that configuration module is to be connected and key;

By the configurator of mobile phone terminal, the IP address of configuration module remote server to be connected;

Remote server is electrically connected in configuration module;

Mobile phones etc. control terminal and connect remote server, issue an order;

The WiFi serial port module that user instruction is handed down in house by remote server;

WiFi serial port module completes switching action corresponding to electrical equipment by microprocessor and other interlock circuit.

Fig. 8 is voltage, temperature acquisition and Balance route software flow pattern, and the hardware components of whole system is not the most complicated, and hardware could the most correctly have to work under the commander of software, and software is adopted and shown a C language, and does not elaborates at this.

The content that this specification is not described in detail belongs to and well known to a person skilled in the art prior art; it is shown and described by relevant case study on implementation although the present invention is own; but; those skilled in the art it is understood that; in the range of claims; can make the various change in form and details, therefore protection scope of the present invention is when being as the criterion with claims.

Claims (3)

1. an electric vehicle lithium battery group intelligent protection device, it is characterised in that: include microprocessor unit (1), numeral isolated location (2), battery detection unit (3), lithium battery group (4), keyboard (5), display screen (6) and WIFI serial port module (7) composition；Described battery detection unit (3) is connected with lithium battery group (4), is used for detecting the voltage of the cell in lithium battery group (4) and temperature and sending microprocessor unit (1) by after the parameter processing of detection by numeral isolated location (2)；Keyboard (5) and microprocessor unit (1) carry out human computer conversation；Display screen (6) is connected with microprocessor unit (1), shows related information parameters；WIF serial port module (7) is connected with microprocessor unit (1), can be checked the relevant information of lithium battery group (4) by mobile phone etc..

A kind of electric vehicle lithium battery group intelligent protection device the most according to claim 1; it is characterized in that: have employed a kind of special battery status monitoring chip LTC6802 of Linear company; battery detection unit (3) is connected with lithium battery group (4), is used for detecting the voltage of the cell in lithium battery group (4) and temperature and sending microprocessor unit (1) by after the parameter processing of detection by numeral isolated location (2).

3. One according to claim 1 Electric vehicle lithium battery group intelligent protection device , it is characterised in that:WiFi serial port module IC4 selects TLN13U06WIFI ,WIFISerial portsModule (7) is connected with microprocessor unit (1), can be checked the relevant information of lithium battery group (4) by mobile phone etc..