CN113206531A - Voltage protection method and device for battery - Google Patents
Voltage protection method and device for battery Download PDFInfo
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
- B60L53/00—Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles
- B60L53/60—Monitoring or controlling charging stations
- B60L53/62—Monitoring or controlling charging stations in response to charging parameters, e.g. current, voltage or electrical charge
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
- B60L58/00—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
- B60L58/10—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries
- B60L58/18—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries of two or more battery modules
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
- H02J7/00308—Overvoltage protection
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/007—Regulation of charging or discharging current or voltage
- H02J7/00712—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters
- H02J7/007182—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters in response to battery voltage
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/007—Regulation of charging or discharging current or voltage
- H02J7/007188—Regulation of charging or discharging current or voltage the charge cycle being controlled or terminated in response to non-electric parameters
- H02J7/007192—Regulation of charging or discharging current or voltage the charge cycle being controlled or terminated in response to non-electric parameters in response to temperature
- H02J7/007194—Regulation of charging or discharging current or voltage the charge cycle being controlled or terminated in response to non-electric parameters in response to temperature of the battery
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/60—Other road transportation technologies with climate change mitigation effect
- Y02T10/70—Energy storage systems for electromobility, e.g. batteries
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/60—Other road transportation technologies with climate change mitigation effect
- Y02T10/7072—Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T90/00—Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02T90/10—Technologies relating to charging of electric vehicles
- Y02T90/12—Electric charging stations
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Abstract
The application provides a voltage protection method and device for a battery. The method comprises the following steps: obtaining a test voltage value, a test current value and a current temperature value which respectively correspond to each battery; obtaining actual voltage values corresponding to the batteries according to the test voltage values, the test current values and the current temperature values; determining a cut-off voltage value by using current temperature values respectively corresponding to the batteries; and performing voltage protection according to the cut-off voltage value and the actual voltage value corresponding to each battery. In the application embodiment, the battery is corrected by using the test voltage value, the test current value and the current temperature value to obtain the accurate actual voltage value corresponding to each battery, the corresponding cut-off voltage is searched according to the current temperature value, and the cut-off voltage value can be dynamically adjusted according to different temperatures, so that the electric quantity of the battery can be released as much as possible, and the utilization rate of the electric quantity of the battery is improved.
Description
Technical Field
The application relates to the technical field of new energy vehicles, in particular to a voltage protection method and device for a battery.
Background
In recent years, more and more people select pure electric vehicles and hybrid electric vehicles which use lithium battery systems as power.
Due to the characteristics of the lithium battery, the voltage which can be provided by the lithium battery is not stable, that is, the voltage of the lithium battery gradually rises when the lithium battery is charged; during discharge, the voltage of the lithium battery gradually drops. Both too high and too low voltages can damage the battery and even cause safety hazards. Therefore, in order to protect the battery, a low cut-off voltage and a high cut-off voltage are conventionally provided in a battery protection system. And when the voltage of the battery is detected to be higher than the high-voltage cut-off voltage or lower than the low-voltage cut-off voltage, the protection measures are started.
When the battery is in a discharging state, because the voltage expressed externally by the battery cannot represent the true state of charge, if the battery is protected according to the preset low-voltage cut-off voltage, a part of electric quantity cannot be released, and the driving range is influenced.
Disclosure of Invention
An object of the embodiments of the present invention is to provide a method and an apparatus for protecting a battery voltage, so as to improve a utilization rate of an electric quantity of the battery.
In a first aspect, an embodiment of the present application provides a method for protecting a voltage of a battery, including: obtaining a test voltage value, a test current value and a current temperature value which respectively correspond to each battery; obtaining actual voltage values corresponding to the batteries according to the test voltage values, the test current values and the current temperature values; determining a cut-off voltage value by using current temperature values respectively corresponding to the batteries; and performing voltage protection according to the cut-off voltage value and the actual voltage value corresponding to each battery.
In the application embodiment, the battery is corrected by using the test voltage value, the test current value and the current temperature value to obtain the accurate actual voltage value corresponding to each battery, the corresponding cut-off voltage is searched according to the current temperature value, and the cut-off voltage value can be dynamically adjusted according to different temperatures, so that the electric quantity of the battery can be released as much as possible, and the utilization rate of the electric quantity of the battery is improved.
Further, the obtaining an actual voltage value corresponding to each battery according to the test voltage value, the test current value, and the current temperature value includes: acquiring a temperature resistance comparison table, and acquiring a corresponding resistance value from the temperature resistance comparison table according to the current temperature value; and obtaining the actual voltage value corresponding to each battery according to the test voltage value, the test current value and the resistance value.
In the embodiment of the application, because the resistance of battery receives the temperature influence, consequently can obtain corresponding resistance through looking up the table according to current temperature value, and then can obtain the accurate actual voltage value of battery, through cut-off voltage value under the prerequisite of guaranteeing to battery safety, improved the utilization ratio of battery power.
Further, the obtaining of the actual voltage value corresponding to each battery according to the test voltage value, the test current value, and the resistance value includes: obtaining a correction voltage value according to the test current value and the resistance value; and obtaining the actual voltage value according to the test voltage value and the correction voltage value.
The voltage of the battery is corrected through the test current value and the resistance value, the actual voltage value is obtained, the dynamic cut-off voltage value and the actual voltage value are compared to judge whether the voltage protection needs to be carried out on the battery, and therefore the voltage protection can be accurately carried out on the battery.
Further, the voltage protection according to the cut-off voltage value and the actual voltage value corresponding to each battery includes: and if the actual voltage value of at least one battery is smaller than or equal to the cut-off voltage value, sending a power-off instruction to the control module to realize the voltage protection of the battery.
In the embodiment of the application, when any battery reaches the voltage protection condition, the power-off protection is started, and the voltage of the battery is prevented from being lower than the cut-off voltage value.
Further, the determining the cut-off voltage value by using the current temperature value corresponding to each battery includes: and acquiring a temperature cut-off voltage comparison table, and acquiring a cut-off voltage value corresponding to the temperature closest to the current temperature value from the temperature cut-off voltage comparison table.
In the embodiment of the application, due to the fact that the temperatures are different and the cut-off voltages corresponding to the batteries are different, the cut-off voltage value is dynamically determined by utilizing the temperatures, and therefore the utilization rate of the batteries is improved while the batteries work in a safe voltage range.
Further, the test voltage value, the test current value and the current temperature value are obtained by synchronous acquisition.
In a second aspect, an embodiment of the present application provides a voltage protection device for a battery, including: the parameter acquisition module is used for acquiring a test voltage value, a test current value and a current temperature value which respectively correspond to each battery; the voltage correction module is used for obtaining actual voltage values corresponding to the batteries according to the test voltage values, the test current values and the current temperature values; the cutoff voltage determining module is used for determining a cutoff voltage value by using the current temperature value corresponding to each battery; and the voltage protection module is used for performing voltage protection according to the cut-off voltage value and the actual voltage value corresponding to each battery.
In a third aspect, an embodiment of the present application provides an electronic device, including: the system comprises a processor, a memory and a bus, wherein the processor and the memory are communicated with each other through the bus; the memory stores program instructions executable by the processor, the processor being capable of performing the method of the first aspect when invoked by the program instructions.
In a fourth aspect, an embodiment of the present application provides a non-transitory computer-readable storage medium, including: the non-transitory computer readable storage medium stores computer instructions that cause the computer to perform the method of the first aspect.
In a fifth aspect, an embodiment of the present application provides an electric vehicle, which includes a power module, a voltage protection device, a current collection module, a control module, and a vehicle system; the voltage protection device is in communication connection with the power supply module, the current acquisition module, the control module and the whole vehicle system respectively; the power supply module comprises at least one battery, each battery is respectively connected with a corresponding voltage acquisition module and a corresponding temperature acquisition module, and the at least one battery is connected in series; the current acquisition module is used for acquiring a test current value; the voltage protection device is used for executing the voltage protection method of the first aspect; the control module is used for receiving a power-off instruction sent by the voltage protection device and carrying out power-off operation; and the whole vehicle system is used for receiving the vehicle running instruction sent by the voltage protection device.
Additional features and advantages of the present application will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the embodiments of the present application. The objectives and other advantages of the application may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments of the present application will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and that those skilled in the art can also obtain other related drawings based on the drawings without inventive efforts.
Fig. 1 is a schematic flow chart of a method for protecting a battery voltage according to an embodiment of the present disclosure;
fig. 2 is a schematic diagram of a voltage protection according to an embodiment of the present disclosure;
fig. 3 is a schematic structural diagram of a voltage protection device of a battery according to an embodiment of the present disclosure;
fig. 4 is a schematic structural diagram of an electronic device according to an embodiment of the present disclosure;
fig. 5 is a schematic structural diagram of an electric vehicle according to an embodiment of the present application.
Detailed Description
Generally, a lithium battery mainly comprises a battery cell and a protection board, the safe use voltage range of the battery cell is 2.5V-4.2V, a single battery cell cannot drive a vehicle to run, and a plurality of battery cells need to be connected in series to form a direct current high voltage of about 300V to drive a motor to work, so that an electric vehicle can run normally.
Taking the lithium battery discharge as an example, after the lithium battery discharges to a certain voltage, the lithium battery should not continue to discharge, otherwise, part of electric quantity of the lithium battery is irreversibly lost, and the battery is seriously damaged completely. Since the lithium battery cannot automatically terminate discharge at a low voltage or actively stop charging at a high voltage, a protection system is required to be designed to control a circuit of the lithium battery. The protection system realizes the protection of the lithium battery by matching the detection circuit with the relay in the loop. The protection principle is that a high cut-off voltage and a low cut-off voltage are set for the lithium battery in advance, and when the voltage of the lithium battery is detected to be higher than the high cut-off voltage or lower than the low cut-off voltage, the relay control circuit is disconnected. For example: the normal use voltage of a certain battery cell is 2.8V-4.2V, and then when the protection system detects that the battery cell voltage reaches 2.8V in the discharging process, the circuit is cut off to prevent the battery cell from continuing to discharge, so that the use of the battery cell voltage lower than 2.8V is avoided.
Because a resistor exists inside the battery, the resistor is generally called battery internal resistance, and the internal resistance of the power battery consists of cell internal resistance and connecting device resistance. Due to the existence of internal resistance in the battery, the battery cell is equivalent to the parallel connection of an ideal power supply and a resistor, and the resistor is equal to the internal resistance of the battery cell in the current state in value. In the discharging process of the battery cell, the battery cell can be divided into a part of voltage, so that the voltage displayed by the battery cell is smaller than the voltage value of the battery cell without load. It is understood that the cells exhibit an external voltage, an internal voltage without load, and a discharge current. Therefore, when the battery cell is in the discharging process, the voltage externally expressed by the battery cell cannot represent the charge state of the battery cell, and if the control is still performed according to the preset cut-off voltage, a considerable part of electric quantity cannot be released, so that the driving range is influenced.
Table 1 shows a relationship between a State of Charge (SOC) and a corresponding voltage when a certain model 100Ah battery of a certain manufacturer is unloaded, it should be noted that corresponding relationships between the SOC, the temperature and the cut-off voltage of batteries of different manufacturers and different models may be different, and table 1 in this embodiment is only an example:
TABLE 1
According to the internal resistance data of the battery cell given by the manufacturer, when the battery cell is discharged by 100A current, the internal resistance is 2.66m omega at-20 ℃, the internal resistance is 0.41m omega at 25 ℃, and the cut-off voltage when the battery cell is discharged is assumed to be the corresponding voltage when the SOC is 0, and the voltage is the voltage when the discharge current is less than or equal to 5A (when the discharge multiplying factor is less than or equal to 0.05C, the voltage can be approximately regarded as no load).
As can be seen from Table 1, the cutoff voltage at 25 ℃ with no cell load was 2.92V, and at-20 ℃ with no cell load was 3.37V.
The actual voltage of the loaded cell at 25 ℃ is calculated by the formula (1):
2.92V+100A*0.41mΩ＝2.96V (1)
the actual voltage when the cell is loaded at-20 ℃ is calculated by the formula (2):
3.37V+100A*2.66mΩ＝3.64V (2)
from the above, if the cutoff is performed according to the actual voltage exhibited when the core is loaded, the SOC of 3.64V is about 40% for the case of-20 ℃. That is, if the voltage protection is performed at a constant cut-off voltage, about 40% of the charge cannot be discharged at-20 ℃.
In order to solve the above problem and improve the utilization rate of the battery on the basis of ensuring the safety of the battery, the embodiment of the present application provides a voltage protection method for dynamically adjusting the cut-off voltage. The technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application.
Fig. 1 is a schematic flow chart of a voltage protection method for a battery according to an embodiment of the present application, and as shown in fig. 1, the method is applied to a battery management system, and includes:
step 101: obtaining a test voltage value, a test current value and a current temperature value which respectively correspond to each battery;
step 102: obtaining actual voltage values corresponding to the batteries according to the test voltage values, the test current values and the current temperature values;
step 103: determining a cut-off voltage value by using current temperature values respectively corresponding to the batteries;
step 104: and performing voltage protection according to the cut-off voltage value and the actual voltage value corresponding to each battery.
In step 101, a test voltage value may be obtained by measuring with a voltage sensor, a test current value may be obtained by measuring with a current sensor, and a current temperature value may be obtained by measuring with a temperature sensor. It should be noted that the battery module includes at least one string of single batteries connected in series, and since the test voltage value, the test current value and the current temperature value corresponding to each battery need to be obtained, the voltage sensor and the temperature sensor need to monitor each battery respectively; since the batteries are connected in series, the current sensor only needs to detect one position.
In step 102, due to the influence of the temperature and the internal resistance of the battery, the test voltage value acquired by the voltage sensor may not be consistent with the actual voltage value, and in order to obtain an accurate actual voltage value, the test voltage value may be corrected according to the test voltage value, the test current value, and the current temperature value of each battery, so as to obtain the actual voltage value of the corresponding battery.
In step 103, since the cut-off voltage values corresponding to different temperatures are different, a temperature cut-off voltage comparison table may be obtained, and the cut-off voltage value corresponding to the current temperature value may be obtained from the temperature cut-off voltage comparison table according to the current temperature value. It is understood that the temperature-cut-off voltage comparison table is pre-written, and may be similar to table 1, and the specific temperature-cut-off voltage value may be set according to practical situations, for example: the SOC can be set to 0, and the cut-off voltage values can be set to-20 deg.C, -10 deg.C, 0 deg.C, 10 deg.C, and 20 deg.C, respectively.
In step 104, the cutoff voltage for each battery is different because the current temperature value for each battery is different. In order to ensure that each battery works in a safe voltage range, whether the corresponding actual voltage value works in the safe voltage range needs to be judged according to the cut-off voltage value of each battery, so that the voltage protection of the battery is realized.
According to the embodiment of the application, the battery is corrected by utilizing the test voltage value, the test current value and the current temperature value, the accurate actual voltage value corresponding to each battery is obtained, the corresponding cut-off voltage is searched according to the current temperature value, and the cut-off voltage value can be dynamically adjusted according to different temperatures, so that the electric quantity of the battery can be released as far as possible, and the utilization rate of the electric quantity of the battery is improved.
On the basis of the above embodiment, the obtaining the actual voltage value corresponding to each battery according to the test voltage value, the test current value, and the current temperature value includes:
acquiring a temperature resistance comparison table, and acquiring a corresponding resistance value from the temperature resistance comparison table according to the current temperature value;
and obtaining the actual voltage value corresponding to each battery according to the test voltage value, the test current value and the resistance value.
In a specific implementation process, because each battery has different impedance when being produced, in addition, the resistance value of each battery can be influenced by factors such as temperature, aging degree and the like, and because the current temperature value has large change and has large influence on the resistance value, the embodiment of the application can write the temperature resistance value comparison table corresponding to each battery in the battery module into a Battery Management System (BMS) during system design. When the resistance value corresponding to each battery is determined, the resistance value corresponding to the current temperature value can be obtained from the temperature resistance value comparison table corresponding to the battery. Obtaining a corrected voltage value of the corresponding battery according to the test current value and the resistance value plan corresponding to each battery; and calculating to obtain an actual voltage value according to the test voltage value and the correction voltage value.
The specific calculation method can obtain the actual voltage value corresponding to each battery according to the following formula (1):
Vi＝Vcelli+Rcelli*I (1)
wherein, ViThe actual voltage value of the ith battery is taken as the actual voltage value of the ith battery; vcelliThe test voltage value of the ith battery is obtained; rcelliThe resistance value of the ith battery; i is a test current value; i is a positive integer.
It can be understood that, in addition to the temperature factor affecting the battery resistance, the temperature resistance comparison table may further include other factors, for example, the use duration, the SOC state, and the like, and the factor affecting the resistance in the specific temperature resistance comparison table may be determined according to actual conditions, which is not specifically limited in this embodiment of the present application.
In the embodiment of the application, because the resistance of battery receives the temperature influence, consequently can obtain corresponding resistance through looking up the table according to current temperature value, and then can obtain the accurate actual voltage value of battery, through cut-off voltage value under the prerequisite of guaranteeing to battery safety, improved the utilization ratio of battery power.
On the basis of the above embodiments, fig. 2 is a schematic diagram of voltage protection provided by the embodiments of the present application, and as shown in fig. 2, the test signal includes a test voltage value V of each batterycelliAnd a current temperature value Tcelli. Then testing voltage value V of each batterycelliCorrecting to obtain actual voltage value ViFor a specific correction method, reference is made to the above embodiments, which are not described herein again. After obtaining the actual voltage value ViAnd then, acquiring a cut-off voltage value corresponding to each battery by inquiring the temperature cut-off voltage comparison table, comparing the cut-off voltage value with a corresponding actual voltage value, and if the actual voltage value of at least one battery is less than or equal to the cut-off voltage value, sending a power-off instruction to the control module to realize the voltage protection of the battery. It is understood that the control module may be a relay.
On the basis of the above embodiment, in order to be able to detect that the actual voltage value of the battery is lower than the cut-off voltage value in time, the test voltage value, the test current value and the current temperature value of each battery are obtained by synchronous acquisition. And the BMS is divided into a BMS mainboard and a BMS slave board, so that the BMS mainboard can be analyzed conveniently, after the voltage sensor collects the test voltage value, the temperature sensor collects the current temperature value and the battery sensor collects the test current value, the BMS slave board carries out time axis marshalling on the test voltage value, the test current value and the current temperature value to form a time-test voltage value-current temperature value-test current value array, and the time-test voltage value-current temperature value-test current value array is sequentially sent to the BMS mainboard according to the sequence of the serial numbers of the batteries from low to high. It should be noted that the grouping of the time axis means that the test voltage value, the current temperature value, and the collection time of the test current value of the group are within a specific time period, for example, the time interval may be less than or equal to 10ms, and a specific time interval may also be set according to an actual situation, which is not specifically limited in this embodiment of the present application. The number of the battery can be preset, and since the battery module is formed by connecting a plurality of batteries in series, the number can be increased from the positive electrode of the battery module, namely, the number of the battery closest to the positive electrode of the battery module is taken as the number 1, and the numbers are increased from the near to the far. Of course, numbering may be started from the negative electrode of the battery module, and numbering may be performed in a random order, in the embodiment of the present application, numbering is performed on the batteries for uniquely identifying the batteries, and when the actual voltage value of the battery is lower than the cut-off voltage value, which battery is specifically known can be known, so that the numbering method of the batteries in the embodiment of the present application is not specifically limited.
Fig. 3 is a schematic structural diagram of a voltage protection device for a battery according to an embodiment of the present disclosure, where the device may be a module, a program segment, or a code on an electronic device. It should be understood that the apparatus corresponds to the above-mentioned embodiment of the method of fig. 1, and can perform various steps related to the embodiment of the method of fig. 1, and the specific functions of the apparatus can be referred to the description above, and the detailed description is appropriately omitted here to avoid redundancy. The device includes: a parameter obtaining module 301, a voltage correcting module 302, a cut-off voltage determining module 303, and a voltage protecting module 304, wherein:
the parameter obtaining module 301 is configured to obtain a test voltage value, a test current value, and a current temperature value corresponding to each battery; the voltage correction module 302 is configured to obtain an actual voltage value corresponding to each battery according to the test voltage value, the test current value, and the current temperature value; the cut-off voltage determining module 303 is configured to determine a cut-off voltage value by using current temperature values respectively corresponding to the batteries; the voltage protection module 304 is configured to perform voltage protection according to the cut-off voltage value and the actual voltage value corresponding to each battery.
On the basis of the foregoing embodiment, the voltage correction module 302 is specifically configured to:
acquiring a temperature resistance comparison table, and acquiring a corresponding resistance value from the temperature resistance comparison table according to the current temperature value;
and obtaining the actual voltage value corresponding to each battery according to the test voltage value, the test current value and the resistance value.
On the basis of the foregoing embodiment, the voltage correction module 302 is specifically configured to:
obtaining a correction voltage value according to the test current value and the resistance value;
and obtaining the actual voltage value according to the test voltage value and the correction voltage value.
On the basis of the foregoing embodiment, the voltage protection module 304 is specifically configured to:
and if the actual voltage value of at least one battery is smaller than or equal to the cut-off voltage value, sending a power-off instruction to the control module to realize the voltage protection of the battery.
On the basis of the above embodiment, the cut-off voltage determining module 303 is specifically configured to:
and acquiring a temperature cut-off voltage comparison table, and acquiring a cut-off voltage value corresponding to the temperature closest to the current temperature value from the temperature cut-off voltage comparison table.
On the basis of the above embodiment, the test voltage value, the test current value, and the current temperature value are obtained by synchronous acquisition.
Fig. 4 is a schematic structural diagram of an entity of an electronic device provided in an embodiment of the present application, and as shown in fig. 4, the electronic device includes: a processor (processor)401, a memory (memory)402, and a bus 403; wherein the content of the first and second substances,
the processor 401 and the memory 402 complete communication with each other through the bus 403;
the processor 401 is configured to call the program instructions in the memory 402 to execute the methods provided by the above-mentioned method embodiments, for example, including: obtaining a test voltage value, a test current value and a current temperature value which respectively correspond to each battery; obtaining actual voltage values corresponding to the batteries according to the test voltage values, the test current values and the current temperature values; determining a cut-off voltage value by using current temperature values respectively corresponding to the batteries; and performing voltage protection according to the cut-off voltage value and the actual voltage value corresponding to each battery.
The processor 401 may be an integrated circuit chip having signal processing capabilities. The Processor 401 may be a general-purpose Processor, including a Central Processing Unit (CPU), a Network Processor (NP), and the like; but may also be a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), an off-the-shelf programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components. Which may implement or perform the various methods, steps, and logic blocks disclosed in the embodiments of the present application. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.
The Memory 402 may include, but is not limited to, Random Access Memory (RAM), Read Only Memory (ROM), Programmable Read Only Memory (PROM), Erasable Read Only Memory (EPROM), Electrically Erasable Read Only Memory (EEPROM), and the like.
The present embodiment discloses a computer program product comprising a computer program stored on a non-transitory computer readable storage medium, the computer program comprising program instructions which, when executed by a computer, enable the computer to perform the method provided by the above-mentioned method embodiments, for example, comprising: obtaining a test voltage value, a test current value and a current temperature value which respectively correspond to each battery; obtaining actual voltage values corresponding to the batteries according to the test voltage values, the test current values and the current temperature values; determining a cut-off voltage value by using current temperature values respectively corresponding to the batteries; and performing voltage protection according to the cut-off voltage value and the actual voltage value corresponding to each battery.
The present embodiments provide a non-transitory computer-readable storage medium storing computer instructions that cause the computer to perform the methods provided by the above method embodiments, for example, including: obtaining a test voltage value, a test current value and a current temperature value which respectively correspond to each battery; obtaining actual voltage values corresponding to the batteries according to the test voltage values, the test current values and the current temperature values; determining a cut-off voltage value by using current temperature values respectively corresponding to the batteries; and performing voltage protection according to the cut-off voltage value and the actual voltage value corresponding to each battery.
Fig. 5 is a schematic structural diagram of an electric vehicle according to an embodiment of the present application, and as shown in fig. 5, a power module 501, a voltage protection device 502, a current collection module 503, a control module 504, and a vehicle system 505; the voltage protection device 502 is in communication connection with the power module 501, the current acquisition module 503, the control module 504 and the vehicle system 505 respectively;
the power module 501 includes at least one battery, each battery is connected to a corresponding voltage acquisition module and a temperature acquisition module, and the at least one battery is connected in series. Fig. 5 shows that each battery is provided with a corresponding temperature acquisition module and voltage acquisition module. It can be understood that if one voltage acquisition module can acquire the test voltage values of a plurality of batteries at the same time, one voltage acquisition module is used, and if one voltage acquisition module can only acquire the test voltage value of one battery, each battery is provided with a corresponding voltage acquisition module. If one temperature acquisition module can acquire the current temperature values of a plurality of batteries simultaneously, one temperature acquisition module is used, and if one temperature acquisition module can only acquire the current temperature value of one battery, each battery is provided with a corresponding temperature acquisition module. In addition, fig. 5 shows that the power module includes 4 batteries, and in practical applications, the number of the batteries may be set according to practical situations, which is not specifically limited in the embodiment of the present application.
The current collecting module 503 is used for collecting a test current value;
the voltage protection device 502 is used for the voltage protection method provided by each of the above embodiments, and the voltage protection device may be specifically a BMS system, and the BMS system may be further divided into a BMS slave board and a BMS master board, wherein the BMS slave board is mainly used for receiving a measured voltage value, a current temperature value and a measured current value; the BMS mainboard is mainly used for calculating and controlling the measured voltage value, the current temperature value and the measured current value, particularly correcting the voltage, judging whether the actual voltage value of each battery is lower than the corresponding cut-off voltage value or not, and sending a power-off instruction when the actual voltage value of the battery is lower than the cut-off voltage value.
The control module 504 is configured to receive a power-off instruction sent by the voltage protection device, and perform a power-off operation;
the vehicle finishing system 505 is configured to receive a vehicle running command sent by the voltage protection device.
In the application embodiment, the battery is corrected by using the test voltage value, the test current value and the current temperature value to obtain the accurate actual voltage value corresponding to each battery, the corresponding cut-off voltage is searched according to the current temperature value, and the cut-off voltage value can be dynamically adjusted according to different temperatures, so that the electric quantity of the battery can be released as much as possible, and the utilization rate of the electric quantity of the battery is improved.
Because the aging degree of the power battery is inconsistent in the use process, the available electric quantity is obviously reduced (the voltage of the battery cell which is aged quickly is reduced quickly when the battery cell is discharged, and the set cut-off voltage is easy to reach); the battery system adopting the dynamic cut-off voltage algorithm considers the influence of battery cell aging (the influence is mainly reflected on the internal resistance of the battery cell) when the cut-off voltage is set, so that the reduction of the available power consumption is closer to the actual condition of the battery cell when the battery system is used, and the influence on the whole vehicle is smaller.
Through online simulation and bench test, the voltage protection method provided by the embodiment of the application has a large improvement on the cut-off voltage of the battery. Through comparison calculation, the precision of the battery cut-off voltage is improved by 50% compared with the fixed value at the temperature of-7 ℃; when the current is discharged by 1 time, the discharge capacity is increased by 20 percent, and the driving range of the vehicle is increased by 100 kilometers.
In the embodiments provided in the present application, it should be understood that the disclosed apparatus and method may be implemented in other ways. The above-described embodiments of the apparatus are merely illustrative, and for example, the division of the units is only one logical division, and there may be other divisions when actually implemented, and for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection of devices or units through some communication interfaces, and may be in an electrical, mechanical or other form.
In addition, units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
Furthermore, the functional modules in the embodiments of the present application may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.
In this document, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions.
The above description is only an example of the present application and is not intended to limit the scope of the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims (10)
1. A method of voltage protection of a battery, comprising:
obtaining a test voltage value, a test current value and a current temperature value which respectively correspond to each battery;
obtaining actual voltage values corresponding to the batteries according to the test voltage values, the test current values and the current temperature values;
determining a cut-off voltage value by using current temperature values respectively corresponding to the batteries;
and performing voltage protection according to the cut-off voltage value and the actual voltage value corresponding to each battery.
2. The method of claim 1, wherein obtaining the actual voltage value corresponding to each battery according to the test voltage value, the test current value, and the current temperature value comprises:
acquiring a temperature resistance comparison table, and acquiring a corresponding resistance value from the temperature resistance comparison table according to the current temperature value;
and obtaining the actual voltage value corresponding to each battery according to the test voltage value, the test current value and the resistance value.
3. The method according to claim 2, wherein the obtaining an actual voltage value corresponding to each battery according to the test voltage value, the test current value and the resistance value comprises:
obtaining a correction voltage value according to the test current value and the resistance value;
and obtaining the actual voltage value according to the test voltage value and the correction voltage value.
4. The method of claim 1, wherein the performing voltage protection according to the cut-off voltage value and the actual voltage value corresponding to each battery comprises:
and if the actual voltage value of at least one battery is smaller than or equal to the cut-off voltage value, sending a power-off instruction to the control module to realize the voltage protection of the battery.
5. The method of claim 1, wherein the determining the cutoff voltage value by using the current temperature value corresponding to each battery comprises:
and acquiring a temperature cut-off voltage comparison table, and acquiring a cut-off voltage value corresponding to the temperature closest to the current temperature value from the temperature cut-off voltage comparison table.
6. The method according to any one of claims 1-5, wherein the test voltage value, the test current value, and the current temperature value are obtained for a synchronous acquisition.
7. A voltage protection device for a battery, comprising:
the parameter acquisition module is used for acquiring a test voltage value, a test current value and a current temperature value which respectively correspond to each battery;
the voltage correction module is used for obtaining actual voltage values corresponding to the batteries according to the test voltage values, the test current values and the current temperature values;
the cutoff voltage determining module is used for determining a cutoff voltage value by using the current temperature value corresponding to each battery;
and the voltage protection module is used for performing voltage protection according to the cut-off voltage value and the actual voltage value corresponding to each battery.
8. An electronic device, comprising: a processor, a memory, and a bus, wherein,
the processor and the memory are communicated with each other through the bus;
the memory stores program instructions executable by the processor, the processor invoking the program instructions to perform the method of any of claims 1-6.
9. A non-transitory computer-readable storage medium storing computer instructions which, when executed by a computer, cause the computer to perform the method of any one of claims 1-6.
10. An electric vehicle is characterized by comprising a power supply module, a voltage protection device, a current acquisition module, a control module and a whole vehicle system; the voltage protection device is in communication connection with the power supply module, the current acquisition module, the control module and the whole vehicle system respectively;
the power supply module comprises at least one battery, each battery is respectively connected with a corresponding voltage acquisition module and a corresponding temperature acquisition module, and the at least one battery is connected in series;
the current acquisition module is used for acquiring a test current value;
the voltage protection device is used for executing the voltage protection method according to any one of claims 1 to 6;
the control module is used for receiving a power-off instruction sent by the voltage protection device and carrying out power-off operation;
and the whole vehicle system is used for receiving the vehicle running instruction sent by the voltage protection device.
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