CN111983466A - Lithium battery safety degree estimation method and device based on voltage and temperature characteristics - Google Patents
Lithium battery safety degree estimation method and device based on voltage and temperature characteristics Download PDFInfo
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- 238000000034 method Methods 0.000 title claims abstract description 49
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- YBJHBAHKTGYVGT-ZKWXMUAHSA-N (+)-Biotin Chemical compound N1C(=O)N[C@@H]2[C@H](CCCCC(=O)O)SC[C@@H]21 YBJHBAHKTGYVGT-ZKWXMUAHSA-N 0.000 claims description 2
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
- G01R31/367—Software therefor, e.g. for battery testing using modelling or look-up tables
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
- G01R31/385—Arrangements for measuring battery or accumulator variables
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
- G01R31/392—Determining battery ageing or deterioration, e.g. state of health
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Abstract
The invention discloses a lithium battery safety degree estimation method and device based on voltage and temperature characteristics, and belongs to the field of battery safety. The invention aims at the problem that the safety of the battery cannot be quantitatively estimated and displayed in the prior art. According to the standard working voltage of the battery, the voltage threshold value and the voltage acquisition value of the battery, the voltage safety coefficient S of the battery is obtainedU(ii) a Obtaining the temperature safety coefficient S of the battery according to the standard working temperature and the temperature threshold value of the battery and the temperature acquisition value of the batteryT(ii) a According to SS＝ω1*SU+ω2*STEstimating the safety degree of the battery; the invention can intuitively estimate and display the safety degree of the battery in real time, and solves the problem of safety judgment of the lithium power battery.
Description
Technical Field
The invention relates to the field of battery safety degree judgment, in particular to a lithium battery safety degree estimation method and device based on voltage and temperature characteristics.
Background
With the increasingly rapid commercialization pace of electric vehicles in the global market, the demand for high-power and high-energy power batteries is rapidly increasing, and the safety of the batteries is receiving more and more attention. Particularly, in recent years, news about accidents such as spontaneous combustion and explosion of lithium batteries occurs, and the safety of lithium batteries is increasingly emphasized. At present, lithium batteries in China are still in the initial stage of technical research and development, and still have many problems in the aspect of safety.
The lithium ion battery is a complex electrochemical system, the failure mechanism of the battery is complex, and the failure mode of the battery is influenced by a plurality of factors, such as the ambient temperature, the discharge depth, the charge and discharge current and the like. Although the state parameters of the battery, such as voltage, current, temperature, etc., can be measured in real time, and the parameters of internal resistance, capacity, SOC, etc., can also be obtained by calculating the actual measurement parameters, the safety of the battery cannot be measured, and is a variable influenced by multiple factors at any time, and the guarantee of the safety is also a precondition for the normal application of the battery system. The problem of quantifying the safety of the battery also becomes a key point and a difficulty in the current battery application research and safety research. At present, domestic scholars are few in the aspect of quantitative research on battery safety, and mainly focus on the aspect of a battery fault diagnosis method. The failure diagnosis is to make a judgment on the failure problem only after the battery fails, and it cannot prevent the battery from failing. In fact, the composition of the battery fault is a gradually changing process, for example, the battery can be evaluated for safety in the using process of the battery, and a quantitative index is given, which plays an important role in preventing the battery accident and guaranteeing the life safety of a user. How to achieve real-time and accurate safety estimation is always a bottleneck problem in the design process of the lithium ion power battery pack.
Disclosure of Invention
In order to solve the problems, the invention provides a method and a device for estimating the safety degree of a lithium battery based on voltage and temperature characteristics, which can intuitively estimate and display the safety degree of the battery in real time and solve the problem of judging the safety of the lithium power battery.
The safety of the battery refers to that the battery does not burn, explode, generate toxic and harmful gases, and do not cause harm to users during the use process, and quantitatively describing the safety degree of the battery during the use process is called as the safety degree of the battery.
The present invention defines a safety boundary of the voltage and the temperature of the battery, defines a safety degree of the battery and estimates the safety degree of the battery, when the voltage and the temperature of the battery are farther from the corresponding safety boundary during the use of the battery, the higher the safety degree of the battery is, and conversely, the more dangerous the working state of the battery is, the lower the safety degree of the battery is.
The invention provides a lithium battery safety degree estimation method based on voltage and temperature characteristics, which comprises the following steps:
acquiring battery voltage and battery temperature in real time, and preprocessing the acquired battery voltage and battery temperature information to obtain a battery voltage acquisition value and a battery temperature acquisition value at a time interval;
obtaining the voltage safety coefficient S of the battery according to the standard working voltage and the voltage threshold value of the battery and the voltage acquisition value of the batteryU；
Obtaining the temperature safety coefficient S of the battery according to the standard working temperature and the temperature threshold value of the battery and the temperature acquisition value of the batteryT；
According to SS＝ω1*SU+ω2*STEstimating the degree of battery safety, wherein SSAs a degree of safety of the battery, omega1And ω2Respectively, a weight coefficient of the battery voltage and a weight coefficient of the battery temperature.
Further, the voltage safety factor S of the batteryUComprises the following steps:
in the formula of USIs a standard operating voltage, UmIs a voltage threshold, UiAnd acquiring a battery voltage value obtained for the ith time interval.
Further, the temperature safety coefficient S of the batteryTComprises the following steps:
in the formula, TSIs a standard working temperature, TmIs a temperature threshold, TiAnd acquiring a value for the battery temperature obtained in the ith time interval.
Further, the weight coefficient omega of the battery voltage1The acquisition method comprises the following steps:
acquiring a characteristic value Fu and a corresponding variable total variance D (u) of the battery voltage safety coefficient;
by passing
Obtaining the contribution rate sigma of the battery voltage varianceu；
The contribution rate sigma of the cell voltage varianceuObtaining the weight coefficient omega of the battery voltage after normalization1。
Further, the weight coefficient omega of the battery temperature2The acquisition method comprises the following steps:
acquiring a characteristic value Ft of the battery temperature safety system and a total variance D (t) of a corresponding variable;
by passing
Obtaining the contribution rate sigma of the temperature variance of the batteryt；
The contribution rate sigma of the battery temperature variancetObtaining the weight coefficient omega of the battery voltage after normalization2。
Further, the method also comprises the step of setting a battery voltage safety boundary and a battery temperature safety boundary;
when the battery is operating within the battery voltage safety margin,obtaining the voltage safety coefficient S of the battery according to the standard working voltage and the voltage threshold value of the battery and the voltage acquisition value of the batteryU；
When the battery works in the battery temperature safety boundary, obtaining the temperature safety coefficient S of the battery according to the standard working temperature and the temperature threshold value of the battery and the battery temperature acquisition valueT。
Furthermore, the battery is a single battery or a battery pack formed by connecting batteries in series and parallel.
Further, the battery is a lead-acid battery, a cadmium-nickel battery, a nickel-hydrogen battery, a lithium ion battery, a fuel cell, a solar battery or a chemical power supply.
Another aspect of the present invention provides a lithium battery safety degree estimation apparatus based on voltage and temperature characteristics, including:
the voltage acquisition unit is used for acquiring the voltage of the battery in real time;
the temperature acquisition unit is used for acquiring the temperature of the battery in real time;
the communication unit is used for transmitting the battery voltage acquired by the voltage acquisition unit and the battery temperature acquired by the temperature acquisition unit to the control unit;
the control unit is used for respectively preprocessing the battery voltage and the battery temperature to obtain a battery voltage acquisition value and a battery temperature acquisition value, and calculating the battery safety by using the lithium battery safety estimation method based on the voltage and temperature characteristics in the first aspect of the invention;
and the display unit is used for displaying the battery safety degree information.
Further, a battery voltage safety boundary and a battery temperature safety boundary are recorded in the control unit, the battery voltage safety boundary is the rated upper limit voltage and the rated lower limit voltage of the battery, and the battery temperature safety boundary is the rated upper limit temperature and the rated lower limit temperature of the battery.
Further, the preprocessing process of the control unit comprises the following steps:
setting a fixed time interval, removing the maximum value and the minimum value of the battery voltage acquired in the fixed time interval, averaging the voltage data of the residual battery to be used as a battery voltage acquisition value, recording, removing the maximum value and the minimum value of the battery temperature acquired in the fixed time interval, averaging the temperature data of the residual battery to be used as a battery temperature acquisition value, and recording.
As described above, the method and apparatus for estimating the safety of a lithium battery based on voltage and temperature characteristics according to the present invention have the following effects:
1. the invention realizes real-time quantitative estimation and display of the safety degree of the battery, is applied to the evaluation of the safety degree of various batteries in various states, solves the technical bottleneck problem that the safety of the battery cannot be early warned in real time in the prior art, and provides effective indexes for judging the safety of the battery.
2. The invention only uses two variables of voltage and temperature to estimate the safety of the battery, the two variables can more comprehensively reflect the working state of the battery, the acquisition is easy, the parameters are few, the model is simple, the calculation result can be conveniently updated, and the real-time performance is realized.
3. The battery voltage weight coefficient and the battery temperature weight coefficient are calculated by adopting a principal component analysis method, so that the mutual influence among variables is eliminated, the workload of parameter selection is reduced, and the accuracy and the efficiency of safety calculation are improved.
4. The method is suitable for estimating the safety degree of various batteries, and has wide applicability, easy realization of hardware circuits and more application occasions.
Drawings
FIG. 1 is a schematic block diagram of a battery safety estimation apparatus according to an embodiment of the present invention;
FIG. 2 is a flow chart of a method for estimating battery safety according to an embodiment of the present invention;
FIG. 3 is a contour plot of battery safety, battery voltage, and battery temperature for an embodiment of the present invention;
FIG. 4 is a contour plot of safety around standard voltage;
Detailed Description
The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention. It is to be noted that the features in the following embodiments and examples may be combined with each other without conflict.
It should be noted that the drawings provided in the following embodiments are only for illustrating the basic idea of the present invention, and the drawings only show the components related to the present invention rather than the number, shape and size of the components in actual implementation, and the type, quantity and proportion of the components in actual implementation may be changed freely, and the layout of the components may be more complicated.
Prior art research related to battery safety has been mainly conducted around fault diagnosis techniques, which are directed to diagnosing the cause of a fault in a battery after the fault in the battery, improving the battery according to the diagnosis result, the method cannot substantially prevent the occurrence of battery failure, but the failure behavior of the battery is a gradual change process in the use process of the battery, and the battery is very close to the extreme case of combustion explosion when the failure behavior of the battery is not obviously shown in many cases, when the battery is burnt or exploded, the destructive power is large, the action is rapid, great loss is caused to personnel and property, therefore, as shown in fig. 1, an embodiment of the present application provides a lithium battery safety degree estimation apparatus based on voltage and temperature characteristics, in the practical application process, the battery is a single battery or a battery pack formed by connecting batteries in series and parallel. And the battery is a lead-acid battery, a cadmium-nickel battery, a nickel-hydrogen battery, a lithium ion battery, a fuel cell, a solar cell or a chemical power supply, the battery of the embodiment adopts a 3.7V/1250mAh ternary material 18650 type lithium ion battery, and the estimation device comprises:
the temperature acquisition unit 200 is used for acquiring battery temperature data in real time, and the temperature acquisition unit of the embodiment adopts a temperature sensor MAX 6613;
the voltage acquisition unit 300 is used for acquiring battery voltage data in real time, and the voltage acquisition unit in the embodiment is a sampling chip LTC 6802;
the battery is used as an electrochemical system, when the working states of the battery are different, the electrochemical reactions in the battery are different, in the prior art, some technical indexes are adopted as main parameters for measuring the performance of the battery, and generally comprise battery capacity, energy density, charging and discharging multiplying power, voltage service life, internal resistance, self-discharge and working temperature, but in the working process of the battery, the battery temperature and voltage can reflect the current battery state most visually, the change of the two indexes can reflect the reaction abnormal degree of the battery to a great extent, and the data acquisition means of the two indexes are more mature, so that the temperature acquisition unit and the voltage acquisition unit are used for respectively acquiring the temperature information and the voltage information of the battery for subsequent calculation of the safety degree of the battery.
The communication unit 400 is used for sending the battery voltage collected by the voltage collection unit and the battery temperature collected by the temperature collection unit to the control unit, and the communication unit of the embodiment adopts a PCA82C250 standard external circuit;
the control unit 500 is configured to respectively pre-process the battery voltage and the battery temperature to obtain a battery voltage acquisition value and a battery temperature acquisition value, and calculate to obtain a battery safety degree value, in practical application, the control unit 500 of this embodiment employs a home-made EVBCM-8133 battery management main control module, and the home-made EVBCM-8133 battery management main control module and the communication unit 400 establish communication connection in a CAN bus communication manner;
the control unit in this embodiment may also be an electronic device, and includes a processor and a memory, where the memory stores instructions of the battery safety degree calculation method in the embodiment, and the processor is configured to call the instructions to execute the battery safety degree estimation method in the embodiment of the present invention, so as to implement real-time estimation of the battery safety degree;
the instructions in the memory may be implemented in the form of software functional units and stored in a computer readable storage medium when being sold or used as a stand-alone product, that is, a part of the technical solution of the present invention or a part of the technical solution that contributes to the prior art in nature may be embodied in the form of a software product stored in a storage medium, and include instructions for causing a computer device (which may be a personal computer, a server, or a network device) to perform all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: u disk, removable hard disk, read only memory, random access memory, magnetic or optical disk, etc. for storing program codes.
In practical application, the processor can be an MSP430 single chip microcomputer, a 51 single chip microcomputer, a DSP, a TMS single chip microcomputer, an STM32 single chip microcomputer, a PIC single chip microcomputer, an AVR single chip microcomputer, an STC single chip microcomputer, a Freescale series single chip microcomputer and the like, and the single chip microcomputer can be connected with a charging and discharging source in a serial port or bus mode.
The display unit 600 is used for displaying information such as battery safety information, voltage, current, alarm signals, discharge time, capacity and safety early warning information, the vehicle-mounted analog load LB-42KW-230VDC is adopted in the embodiment, the display unit CAN be a desktop computer, a notebook computer, an LED liquid crystal display screen, a UM12864 liquid crystal display screen and the like, and the display unit 600 and the control unit CAN select RS232, RS485 and RS422 serial communication interfaces or Ethernet transmission or CAN bus transmission.
As shown in fig. 1, the temperature acquisition unit 200 and the voltage acquisition unit 300 are respectively connected to the battery 100, the output ends of the temperature acquisition unit 200 and the voltage acquisition unit 300 are connected to the control unit 400 through the communication unit 400, and the control unit 400 sends the safety degree information obtained by estimation to the display unit 600 to display the safety value of the battery.
The method for estimating the safety degree of the lithium battery based on the voltage and temperature characteristics comprises the following steps:
s1, collecting the voltage and temperature of the battery in real time, wherein the temperature collecting unit 200 and voltage collecting of the embodiment are far away300 the collection frequency of the battery information is 10 ms/time, the control unit 500 receives the collected original battery voltage information { u } through the communication unit 4001，u2…ul… and raw battery temperature information t1,t2…tl…}；
Setting a battery voltage safety boundary and a battery temperature safety boundary, where the present embodiment defines a battery rated voltage and a battery rated temperature as a voltage safety boundary and a temperature safety boundary of a battery, and stores the values of the boundaries in the control unit 500, and when the voltage and the temperature of the battery are within an operable range formed by the corresponding safety boundaries, if the voltage and the temperature of the battery are farther from the voltage safety boundary and the temperature safety boundary, the higher the safety of the battery is, i.e., the higher the operational safety of the battery is, and conversely, the lower the safety of the battery is, i.e., the more dangerous the operational state of the battery is, the battery voltage safety boundary is the rated upper and lower limit voltages of the battery, and the battery temperature safety boundary is the rated upper and lower limit temperatures of the battery.
S2, obtaining accurate real-time voltage and temperature data through filtering, where the filtering method may be arithmetic mean filtering, moving average filtering, median average filtering, and various filtering methods based on digital signals, and the filtering method of this embodiment is: setting the fixed time interval as 100ms, removing the maximum value and the minimum value of the battery voltage acquired within the fixed time interval of 100ms, and averaging the voltage data of the residual battery to obtain a battery voltage acquisition value { U1, U2…Ui… }, and recording; removing the maximum value and the minimum value of the battery temperature collected in a fixed time interval, and averaging the residual battery temperature data to obtain a battery temperature collection value { T }1，T2…Ti… }, and recording.
S3, when the voltage data recorded by the control unit 500 is in the working range of the ternary lithium battery, namely working in the safe boundary of the voltage parameter of the ternary lithium battery, comparing the voltage acquisition value of the battery with the standard working voltage Us, and combining the voltage threshold Um to obtain the voltage safety of the batteryCoefficient SU：
In the formula of USIs a standard operating voltage, UmIs a voltage threshold, UiAnd acquiring a battery voltage value obtained for the ith time interval. The voltage safety factor represents the current working state of the power battery, the minimum value is 0 under the normal working state of the battery, and the more the value is close to 0, the more abnormal the working state of the battery is proved.
S4, when the temperature data recorded by the control unit 500 is in the working range of the ternary lithium battery, namely working in the safety boundary of the temperature parameter of the ternary lithium battery, comparing the temperature acquisition value of the battery with the standard working temperature, and combining the temperature threshold value to obtain the safety coefficient of the temperature to obtain the temperature safety coefficient S of the batteryT；
In the formula, TSIs a standard working temperature, TmIs a temperature threshold, TiAnd acquiring a value for the battery temperature obtained in the ith time interval. The voltage safety factor represents the current working state of the power battery, the minimum value is 0 under the normal working state of the battery, and the more the value is close to 0, the more abnormal the working state of the battery is proved.
When any value of the voltage safety coefficient and the temperature safety coefficient of the battery is too low, the working state of the battery is very dangerous, so that the influence of the voltage safety coefficient and the temperature safety coefficient on the safety degree of the battery when the voltage safety coefficient and the temperature safety coefficient are too low is increased by adding a weight variable. According to the voltage safety coefficient and the temperature safety coefficient and the degree close to zero, the embodiment obtains the correlation between the current battery voltage safety coefficient and the temperature safety coefficient and the current battery safety degree by using a principal component analysis method. As shown in step S3 and step S4.
S3, obtaining weight coefficient omega of battery voltage1The method specifically comprises the following steps:
s31, obtaining the characteristic value F of the battery voltage safety coefficient data set { Su1, Su2, … }uAnd the corresponding variable total variance d (u);
s32, passing
Obtaining the contribution rate sigma of the battery voltage varianceu；
S33, calculating the contribution rate sigma of the battery voltage varianceuObtaining the weight coefficient omega of the battery voltage after normalization1。
S4, acquiring weight coefficient omega of battery temperature2The method specifically comprises the following steps:
s41, obtaining characteristic values F of the battery temperature safety system data set { St1, St2, … }tAnd the total variance d (t) of the corresponding variables;
s42, passing
Obtaining the contribution rate sigma of the temperature variance of the batteryt；
S43, calculating the contribution rate sigma of the battery temperature variancetObtaining the weight coefficient omega of the battery voltage after normalization2。
S5, according to SS＝ω1*SU+ω2*STEstimating the degree of battery safety, wherein SSThe safety of the battery.
In practical application, different standard voltages and standard temperatures are adopted for different power battery systems, and different voltage and temperature thresholds are selected according to different batteries, so that more effective battery safety can be obtained. By analyzing the difference between the voltage and the temperature of the battery under the working condition and the standard value, the Ss is one percent under the ideal working state of the battery. Therefore, the more the value of the safety degree Ss of the power battery obtained through the test approaches to one hundred, the higher the safety of the battery at the moment is represented; the lower the value of the safety level Ss of the power cell is obtained, the higher the probability of the power cell module being dangerous under the condition is represented.
In practical application, different standard voltages and standard temperatures are adopted for different power battery systems, and different voltage and temperature thresholds are selected according to different batteries, so that more effective battery safety can be obtained. By analyzing the difference between the voltage and the temperature of the battery under the working condition and the standard value, the Ss is one percent under the ideal working state of the battery. Therefore, the more the value of the safety degree Ss of the power battery obtained through the test approaches to one hundred, the higher the safety of the battery at the moment is represented; the lower the value of the safety level Ss of the power cell is obtained, the higher the probability of the power cell module being dangerous under the condition is represented.
S6, the real-time safety degree is judged through the judging unit, the battery state at the moment is further judged, and the safety degree value of the current battery and corresponding battery early warning information are displayed in a percentage mode through the display unit 600;
the control unit 500 is configured to calculate the battery safety degree value, but in an actual application process, in order to enable a user to use the safety degree more intuitively and clearly, the control unit 500 establishes a safety degree comparison table according to the safety degree value, where the safety degree comparison table is composed of a plurality of safety intervals, and each safety interval corresponds to the battery safety condition at the current time; the control unit 500 is provided with a judging unit, which matches the obtained safety degree value with the safety interval to obtain the battery safety condition at the current moment, and when the estimated safety degree value satisfies the safety degree stage, different early warning information is provided, and the segments of the embodiment are as follows:
| safe phase | Safety degree value range | Display unit early warning information |
| 1 | 0-20 | The battery reaches a |
| 2 | 20-40 | The battery reaches a |
| 3 | 40-60 | Potential danger exists in the battery |
| 4 | 60-80 | General state of the |
| 5 | 80-100 | Good battery state |
The safety degree segmentation method described in this embodiment divides a large number of experiments of the battery and basic parameters of the battery, the safety degree value of the battery in this embodiment is in a percentage system form, when the safety degree value of the battery is within a range of [80,100], it indicates that the battery is good and can be used continuously, when the safety degree value of the battery is within a range of [60,80 ], it indicates that the battery is in a normal state and needs to be slightly noticed by a user, when the safety degree value of the battery is within a range of [40, 60 ], it indicates that the battery has a potential danger, during the use, the user needs to pay more attention, when the safety degree value of the battery is within a range of [20, 40 ], the battery has already reached a dangerous degree, at this time, the battery should be stopped and replaced, and when the safety degree value of the battery is within a range of [0,20 ], the surface battery reaches a serious dangerous degree, indicating that a burning explosion condition occurs or the burning and explosion are very easy to cause, and at the moment, the battery is disassembled and properly transferred by adopting an emergency treatment mode according to actual needs.
Contour lines drawn by the battery safety degree estimation result of the embodiment are shown in fig. 3 and 4, in fig. 3, the abscissa is the battery voltage, the ordinate is the battery temperature, and the safety degrees under different voltages and temperatures are shown in the diagram in the form of contour line diagrams, wherein fig. 4 is a contour line diagram near the standard voltage.
The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.
Claims (10)
1. A lithium battery safety degree estimation method based on voltage and temperature characteristics is characterized in that: the method comprises the following steps:
acquiring a battery voltage acquisition value and a battery temperature acquisition value in a time interval;
obtaining the voltage safety coefficient S of the battery according to the standard working voltage and the voltage threshold value of the battery and the voltage acquisition value of the batteryU；
Obtaining the temperature safety coefficient S of the battery according to the standard working temperature and the temperature threshold value of the battery and the temperature acquisition value of the batteryT；
According to SS＝ω1*SU+ω2*STEstimating the degree of battery safety, wherein SSAs a degree of safety of the battery, omega1And ω2Respectively, a weight coefficient of the battery voltage and a weight coefficient of the battery temperature.
2. The lithium battery safety degree estimation method based on voltage and temperature characteristics according to claim 1, wherein: voltage safety factor S of the batteryUComprises the following steps:
in the formula of USIs a standard operating voltage, UmIs a voltage threshold, UiAnd acquiring a battery voltage value obtained for the ith time interval.
3. The lithium battery safety degree estimation method based on voltage and temperature characteristics according to claim 1, wherein:
temperature safety coefficient S of batteryTComprises the following steps:
in the formula, TSIs a standard working temperature, TmIs a temperature threshold, TiAnd acquiring a value for the battery temperature obtained in the ith time interval.
4. The lithium battery safety degree estimation method based on voltage and temperature characteristics according to claim 1, wherein: weight coefficient ω of the battery voltage1The acquisition method comprises the following steps:
acquiring a characteristic value Fu and a corresponding variable total variance D (u) of the battery voltage safety coefficient;
by passing
Obtaining the contribution rate sigma of the battery voltage varianceu；
The contribution rate sigma of the cell voltage varianceuObtaining the weight coefficient omega of the battery voltage after normalization1。
5. The lithium battery safety degree estimation method based on voltage and temperature characteristics according to claim 1, wherein: weight coefficient ω of the battery temperature2The acquisition method comprises the following steps:
acquiring a characteristic value Ft of the battery temperature safety system and a total variance D (t) of a corresponding variable;
by passing
Obtaining the contribution rate sigma of the temperature variance of the batteryt；
The contribution rate sigma of the battery temperature variancetObtaining the weight coefficient omega of the battery voltage after normalization2。
6. The lithium battery safety degree estimation method based on voltage and temperature characteristics according to claim 1, wherein: setting a battery voltage safety boundary and a battery temperature safety boundary;
when the battery works in the battery voltage safety boundary, obtaining the voltage safety coefficient S of the battery according to the standard working voltage and the voltage threshold of the battery and the battery voltage acquisition valueU；
When the battery works in the battery temperature safety boundary, obtaining the temperature safety coefficient S of the battery according to the standard working temperature and the temperature threshold value of the battery and the battery temperature acquisition valueT。
7. The lithium battery safety degree estimation method based on voltage and temperature characteristics according to claim 1, wherein: the battery is a single battery or a battery pack formed by connecting batteries in series and in parallel, and the battery is a lead-acid battery, a cadmium-nickel battery, a nickel-hydrogen battery, a lithium ion battery, a fuel battery, a solar battery or a chemical power supply.
8. A lithium battery safety degree estimation device based on voltage and temperature characteristics is characterized in that: the method comprises the following steps:
the voltage acquisition unit is used for acquiring the voltage of the battery in real time;
the temperature acquisition unit is used for acquiring the temperature of the battery in real time;
the communication unit is used for transmitting the battery voltage acquired by the voltage acquisition unit and the battery temperature acquired by the temperature acquisition unit to the control unit;
the control unit is used for respectively preprocessing the battery voltage and the battery temperature to obtain a battery voltage acquisition value and a battery temperature acquisition value, and calculating the battery safety by using the lithium battery safety estimation method based on the voltage and temperature characteristics according to claims 1-7;
and the display unit is used for displaying the battery safety degree information.
9. The lithium battery safety degree estimation apparatus according to claim 8, wherein: the control unit records a battery voltage safety boundary and a battery temperature safety boundary.
10. The lithium battery safety degree estimation apparatus according to claim 8, wherein: the pretreatment process of the control unit comprises the following steps:
setting a fixed time interval, removing the maximum value and the minimum value of the battery voltage acquired in the fixed time interval, averaging the voltage data of the residual battery to be used as a battery voltage acquisition value, recording, removing the maximum value and the minimum value of the battery temperature acquired in the fixed time interval, averaging the temperature data of the residual battery to be used as a battery temperature acquisition value, and recording.
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