CN113206316A - Cooling system and method for preventing heat spread of battery pack - Google Patents
Cooling system and method for preventing heat spread of battery pack Download PDFInfo
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- CN113206316A CN113206316A CN202110368964.1A CN202110368964A CN113206316A CN 113206316 A CN113206316 A CN 113206316A CN 202110368964 A CN202110368964 A CN 202110368964A CN 113206316 A CN113206316 A CN 113206316A
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- 238000001816 cooling Methods 0.000 title claims abstract description 85
- 238000000034 method Methods 0.000 title claims abstract description 14
- 239000003507 refrigerant Substances 0.000 claims abstract description 77
- 238000010583 slow cooling Methods 0.000 claims abstract description 61
- 238000001514 detection method Methods 0.000 claims abstract description 27
- 239000002826 coolant Substances 0.000 claims description 13
- 230000003247 decreasing effect Effects 0.000 claims description 4
- 230000005611 electricity Effects 0.000 claims description 3
- 230000007480 spreading Effects 0.000 claims description 3
- 230000009467 reduction Effects 0.000 claims description 2
- 230000000630 rising effect Effects 0.000 claims 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 17
- 239000000779 smoke Substances 0.000 description 4
- 238000013461 design Methods 0.000 description 3
- 239000012774 insulation material Substances 0.000 description 3
- 230000009471 action Effects 0.000 description 2
- 238000009529 body temperature measurement Methods 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 230000003111 delayed effect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000004880 explosion Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000002035 prolonged effect Effects 0.000 description 2
- 238000005507 spraying Methods 0.000 description 2
- 238000006467 substitution reaction Methods 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000004964 aerogel Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000013021 overheating Methods 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/60—Heating or cooling; Temperature control
- H01M10/61—Types of temperature control
- H01M10/613—Cooling or keeping cold
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/48—Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte
- H01M10/486—Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte for measuring temperature
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/60—Heating or cooling; Temperature control
- H01M10/63—Control systems
- H01M10/633—Control systems characterised by algorithms, flow charts, software details or the like
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/60—Heating or cooling; Temperature control
- H01M10/65—Means for temperature control structurally associated with the cells
- H01M10/655—Solid structures for heat exchange or heat conduction
- H01M10/6556—Solid parts with flow channel passages or pipes for heat exchange
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/60—Heating or cooling; Temperature control
- H01M10/65—Means for temperature control structurally associated with the cells
- H01M10/656—Means for temperature control structurally associated with the cells characterised by the type of heat-exchange fluid
- H01M10/6561—Gases
- H01M10/6563—Gases with forced flow, e.g. by blowers
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/60—Heating or cooling; Temperature control
- H01M10/65—Means for temperature control structurally associated with the cells
- H01M10/656—Means for temperature control structurally associated with the cells characterised by the type of heat-exchange fluid
- H01M10/6567—Liquids
-
- 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
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
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- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Automation & Control Theory (AREA)
- Secondary Cells (AREA)
- Battery Mounting, Suspending (AREA)
Abstract
The invention provides a cooling system and a method for preventing heat spread of a battery pack, wherein the system comprises: the detection module is used for collecting thermal runaway judgment parameters; the judging module is used for judging whether the battery pack is in a thermal runaway state or not according to the thermal runaway judging parameter and sending a signal for entering a slow cooling mode when the battery pack is in the thermal runaway state; and the cooling module is used for executing cooling operation according to the signal of entering the slow cooling mode, and the cooling operation reduces the temperature of the battery pack or the battery cell through secondary refrigerant filled in the cooling pipe outside the battery pack or the battery cell. The method comprises the following steps: judging whether the battery pack enters a thermal runaway state or not; and when the battery pack enters a thermal runaway state, entering a slow cooling mode, and controlling the secondary refrigerant to perform cooling operation on the battery pack through indirect heat exchange. The system provided by the invention has low input cost, and can prolong the escape time of passengers when the battery pack is out of control due to heat.
Description
Technical Field
The invention relates to the technical field of battery thermal management, in particular to a cooling system and a cooling method for preventing battery pack thermal spread.
Background
Thermal runaway refers to the phenomenon of overheating, ignition and explosion of a battery pack caused by an exothermic chain reaction and having a rapidly changing self-temperature rise rate. After the battery pack enters a thermal runaway state, in order to give passengers a certain escape time, technicians can design safety protection measures for the battery, and the common protection measures are as follows:
1. carry out thermal-insulated between electric core and module, use thermal insulation material in the battery package inside promptly, prevent the time that the inside heat of battery package spreads.
2. The fire extinguishing agent is used for spraying, namely, when a BMS (battery management system) sends out a thermal runaway alarm, the centralized cooling fire extinguishing is carried out on the position where the thermal runaway happens in the battery pack.
3. The design heat conduction exhaust pipe, that is to say, the heat conduction pipeline for exhaust smoke when the thermal runaway is added on the existing battery pack aims at leading out heat and smoke generated by the thermal runaway as soon as possible and relieving further thermal spread and explosion caused by overlarge pressure of the battery pack.
The disadvantages of the above-mentioned safeguards are as follows:
1. carry out between electric core and module heat-insulating technical scheme, the thermal insulation material that uses usually is aerogel etc. this scheme is limited to and keeps apart the position that takes place unusual heat after thermal runaway takes place, plays the effect of giving the passenger time of fleing, however whatever kind of thermal insulation material, it is limited to thermal isolation, this scheme does not relate to heat conduction, when thermal runaway is comparatively serious, for example when producing more heat respectively in a plurality of positions of battery package suddenly, the general rate can't prevent the big area thermal runaway of battery package.
2. The technical scheme of spraying by using the fire extinguishing agent has no mature case on passenger cars. In addition, the scheme relates to the action of directly introducing foreign objects to the thermal runaway position of the battery pack for contact, once the foreign objects are mistakenly sprayed, the normal use of a subsequent vehicle is influenced, and once the thermal runaway spread is caused by the spray leakage, the effect of providing sufficient escape time for passengers cannot be achieved.
3. The technical scheme of designing the heat conduction pipeline has high requirements on the design space of the battery pack and has extremely high cost. In addition, in some thermal runaway situations, the battery pack or the battery core parameters may be abnormal, but smoke and more heat are not generated yet, and the heat conduction and smoke exhaust pipe cannot well conduct heat.
Disclosure of Invention
Accordingly, the present invention is directed to a cooling system and method for preventing heat spreading of a battery pack.
The invention provides a cooling system for preventing heat spread of a battery pack, which comprises:
the detection module is used for collecting thermal runaway judgment parameters;
the judging module is used for judging whether the battery pack is in a thermal runaway state or not according to the thermal runaway judging parameter and sending a signal for entering a slow cooling mode when the battery pack is in the thermal runaway state;
and the cooling module is used for executing cooling operation according to the signal of entering the slow cooling mode, and the cooling operation reduces the temperature of the battery pack or the battery cell through secondary refrigerant filled in the cooling pipe outside the battery pack or the battery cell.
Optionally, the detection module includes:
the temperature detection unit is used for detecting the temperature of the battery pack or the battery core;
the voltage detection unit is used for detecting the voltage of the battery pack or the battery cell;
the judging module judges that the battery pack is in a thermal runaway state when the temperature of the battery pack or the battery core is greater than a first temperature threshold, the temperature rise rate is not less than a set rate threshold and the temperature continuously rises to exceed a first time threshold; and/or
The judging module judges that the battery pack is in a thermal runaway state when the voltage of the battery pack or the battery core is reduced, the percentage of a reduction value in the initial voltage exceeds a set percentage threshold, the temperature rise rate is not less than a rate threshold, and the temperature continuously rises to exceed a first duration threshold; and/or
And the judging module judges that the battery pack is in a thermal runaway state when the temperature difference between the single battery cell and the battery pack is not less than the temperature difference threshold.
Optionally, after the determining module sends out the signal for entering the slow cooling mode,
if the temperature of the battery pack or the battery core is not greater than the first temperature threshold, and the temperature rise rate is less than the rate threshold and the temperature does not rise continuously any more, the judging module sends a signal for exiting the slow cooling mode; and/or
If the voltage of the battery pack or the battery cell stops decreasing and the time for stopping decreasing is not less than a second duration threshold, the judging module sends a signal for exiting the slow cooling mode; and/or
And if the temperature difference between the single battery cell and the battery pack is smaller than the temperature difference threshold value, the judging module sends a signal for exiting the slow cooling mode.
Optionally, the cooling module further comprises:
the secondary refrigerant inlet temperature detection unit is used for detecting the temperature of the secondary refrigerant before the secondary refrigerant is contacted with the battery pack;
the secondary refrigerant outlet temperature detection unit is used for detecting the temperature of the secondary refrigerant after the secondary refrigerant is contacted with the battery pack;
the secondary refrigerant flow rate control unit is used for controlling the flow rate of the secondary refrigerant in the cooling pipe;
when the temperature of the secondary refrigerant before or after the secondary refrigerant is contacted with the battery pack is higher than a first temperature, the secondary refrigerant flow speed control unit controls the secondary refrigerant to flow at a first flow speed;
when the temperature of the secondary refrigerant before or after the secondary refrigerant is contacted with the battery pack is higher than a second temperature, the secondary refrigerant flow rate control unit controls the secondary refrigerant to flow at a second flow rate;
and when the temperature of the secondary refrigerant before or after the secondary refrigerant is in contact with the battery pack is higher than the third temperature, the secondary refrigerant flow velocity control unit controls the flow velocity of the secondary refrigerant to flow at a third flow velocity.
Optionally, the second flow rate value is at least 130% of the first flow rate value, and the third flow rate value is at least 160% of the second flow rate value.
Optionally, the system further comprises a broadcasting module, configured to receive a signal sent by the control module to enter the slow cooling mode, and broadcast preset voice content to the inside or the outside of the vehicle.
The invention also provides a cooling method for preventing the heat spread of the battery pack, which comprises the following steps:
judging whether the battery pack enters a thermal runaway state or not;
and when the battery pack enters a thermal runaway state, entering a slow cooling mode, and controlling the secondary refrigerant to perform cooling operation on the battery pack through indirect heat exchange.
Optionally, the step of determining whether the battery pack enters a thermal runaway state includes:
when any one of the following conditions is met, judging that the battery pack enters a thermal runaway state:
the temperature of the battery pack or the battery core is greater than a first temperature threshold, the temperature rise rate is not less than a set rate threshold, and the temperature rise rate continuously exceeds a first duration threshold; or
Voltage drop is generated by the voltage of the battery pack or the battery core, the percentage of the drop value in the initial voltage exceeds a set percentage threshold, the temperature rise rate is not less than a rate threshold, and the temperature continuously rises to exceed a first duration threshold; or
The temperature difference between the single battery cell and the battery pack is not smaller than the temperature difference threshold.
Optionally, when the battery pack enters a thermal runaway state, entering a slow cooling mode, and after the step of controlling the coolant to perform a cooling operation on the battery pack through indirect heat exchange, the method further includes:
and the slow cooling mode is not exited until the energy supply module for supplying energy to the cooling module consumes complete electricity.
Optionally, when the battery pack enters a thermal runaway state, entering a slow cooling mode, and after the step of controlling the coolant to perform a cooling operation on the battery pack through indirect heat exchange, the method further includes:
exiting slow cool mode when any of the following conditions are met:
the temperature of the battery pack or the battery core is not greater than a first temperature threshold, and the temperature rise rate is less than a rate threshold and is not continuously increased; and/or
The voltage of the battery pack or the battery cell stops dropping, and the time for stopping dropping is not less than a second duration threshold; and/or
The temperature difference between the single battery cell and the battery pack is smaller than a temperature difference threshold value.
In conclusion, the invention has the following beneficial effects: through the strategy of definitely entering and exiting the slow cooling mode, the battery pack can be effectively subjected to heat conduction treatment when thermal runaway occurs, the further occurrence of large-area thermal runaway is delayed, the escape time of passengers is prolonged, and the battery pack cannot be damaged when misjudgment occurs. In addition, the invention has low space requirement corresponding to equipment, and relates to equipment which has simple structure and is convenient to maintain and can greatly reduce the cost required by the thermal runaway protection scheme.
The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical means of the present invention more clearly understood, the present invention may be implemented in accordance with the content of the description, and in order to make the above and other objects, features, and advantages of the present invention more clearly understood, the following preferred embodiments are described in detail with reference to the accompanying drawings.
Drawings
Fig. 1 is a schematic system architecture diagram of a cooling system according to an embodiment of the present invention.
Fig. 2 is a functional diagram of a slow cooling mode according to an embodiment of the present invention.
Description of the reference numerals
1-battery pack, 2-radiator, 3-water pump, 4-expansion pot.
Detailed Description
The following detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.
The terms first, second and the like in the description and in the claims of the present invention are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order.
The invention provides a cooling system for preventing thermal spread of a battery pack, which is used for slowing down the thermal spread of the battery pack in a thermal runaway state and providing sufficient escape time for passengers. As shown in fig. 1, the cooling system includes a detection module, a determination module, and a cooling module.
In the invention, the detection module is used for collecting the thermal runaway judgment parameters. In this embodiment, the thermal runaway determination parameter includes a temperature of the battery pack or the battery core and a voltage of the battery pack or the battery core, and the corresponding detection module includes a temperature detection unit and a voltage detection unit, where the temperature detection unit is configured to detect the temperature of the battery pack or the battery core, and the voltage detection unit is configured to detect the voltage of the battery pack or the battery core. Specifically, the detection module in the present embodiment includes a BMS slave board.
It should be noted that, the above-mentioned battery cell refers to a single battery cell constituting a battery pack, the battery cell is a minimum unit of a battery system, a plurality of battery cells can be combined to form a module, and a plurality of module combinations can form a battery pack. When a battery pack is described as being in a thermal runaway state, the thermal runaway state may be that a single or multiple battery cells in the battery pack are in the thermal runaway state, the thermal runaway state may also be that one or multiple modules in the battery pack are in the thermal runaway state, and the thermal runaway state may also be that all modules in the entire battery pack are in the thermal runaway state. If thermal runaway begins to only take place in single electric core, then the very big probability of thermal runaway of single electric core can stretch to adjacent electric core, develops gradually to electric core module, causes the thermal runaway of whole battery package at last.
In the invention, the judging module is used for judging whether the battery pack is in the thermal runaway state according to the thermal runaway judging parameter and sending a signal for entering or exiting the slow cooling mode according to whether the battery pack is in the thermal runaway state. In this embodiment, the determination module includes a BMS motherboard and a vehicle control unit, the BMS motherboard is configured to receive a thermal runaway determination parameter detected by the BMS board, determine whether the battery pack is in a thermal runaway state according to the thermal runaway determination parameter, transmit a determination result of whether the battery pack is in the thermal runaway state to the vehicle control unit, and the vehicle control unit determines whether to send a signal to enter or exit the slow cooling mode according to the determination result. Specifically, the vehicle control unit sends a signal for entering the slow cooling mode when the vehicle control unit is in thermal runaway, and sends a signal for exiting the slow cooling mode when the thermal runaway is controlled. In addition, in the present invention, the logic for determining whether the battery pack is in the thermal runaway state is as follows:
if the temperature of the battery pack or the battery core is greater than a first temperature threshold (for example, 80 ℃), and the temperature rise rate is not less than a set rate threshold (for example, 1 ℃/s) and the temperature continues to rise for more than a first time threshold (for example, 3s), judging that the battery pack is in a thermal runaway state;
and/or voltage drop is generated on the battery pack or the battery core, the percentage of the drop value in the initial voltage exceeds a set percentage threshold (for example, 25%), and when the temperature rise rate is not less than the set rate threshold and the temperature continuously rises to exceed a first duration threshold, the battery pack is judged to be in a thermal runaway state;
and/or when the temperature difference between the single battery cell and the battery pack is not less than the temperature difference threshold (for example, 5 ℃), judging that the battery pack is in a thermal runaway state.
After the judgment module sends out a signal for entering the slow cooling mode, if the thermal runaway determination parameter meets any one of the following conditions, the judgment module sends out a signal for exiting the slow cooling mode:
when the temperature of the battery pack or the battery core is not greater than a first temperature threshold value, the temperature rise rate is smaller than a rate threshold value and the temperature does not rise continuously any more, the judging module sends a signal for exiting the slow cooling mode;
and/or the judging module sends out a signal for exiting the slow cooling mode when the voltage of the battery pack or the battery cell stops dropping and the time for stopping dropping is not less than a second duration threshold (for example, 10 s);
and/or the judging module sends a signal for exiting the slow cooling mode when the temperature difference between the single battery cell and the battery pack is smaller than a temperature difference threshold;
and when the judging module sends a signal for exiting the slow cooling mode, the cooling module exits the slow cooling mode according to the received signal and stops the cooling operation of the battery pack.
It should be noted that, since the thermal runaway cooling control is related to the safety of passengers, in the above system, the automatic exit condition of the slow cooling mode may not be set, and the situation that the battery pack heat spread cannot be prevented in an extreme case is avoided. For example, under the condition of impact, the battery pack enters a thermal runaway state for the first time, the thermal runaway state is controlled under the action of the cooling system, the judging module sends a signal for exiting the slow cooling mode according to the thermal runaway judging parameter, the judging module is damaged immediately, the battery pack enters the thermal runaway state again at the moment, and the judging module cannot send a signal for entering the slow cooling mode again.
In the present invention, the cooling module functions to receive a signal to enter or exit the slow cooling mode and perform or stop the cooling operation according to the signal to enter or exit the slow cooling mode. The cooling module includes a master controller and a slow-cool submodule.
The main controller is used for receiving a signal for entering or exiting the cooling mode, and when the main controller receives the signal for entering the cooling modeCooling downAnd when the mode signal is received, the sub-modules or units (such as the slow cooling sub-modules, a coolant inlet temperature detection unit and a coolant outlet temperature detection unit) of the cooling module are controlled to start to operate, and corresponding detection or cooling operation is performed on the battery pack. It should be noted that the cooling operation reduces the temperature of the battery pack or the battery cell by the coolant, and the coolant does not directly contact the battery pack. In the present invention, the slow cooling sub-module is used to control the coolant to perform a cooling operation, and the slow cooling sub-module includes a coolant flow rate control unit for controlling the flow rate of the coolant.
In the present invention, the slow cooling sub-module performs a cooling operation by controlling the apparatus as in fig. 2. As shown in fig. 2, the apparatus required to be used in the slow cooling mode includes: radiator 2, water pump 3, expansion tank 4 and a plurality of cooling pipes. A plurality of cooling pipes (not shown) are arranged around the battery pack 1, liquid secondary refrigerant is filled in the cooling pipes, the cooling pipes are led to the radiator 2 from the battery pack 1, an outlet of the radiator 2 is divided into two branches, one branch is led to an inlet of the water pump 3, and the other branch is led to an inlet of the expansion water tank 4; at the outlet of the water pump 3, the cooling pipe leads to the battery pack 1, and at the outlet of the expansion tank 4, the cooling pipe leads to a cooling pipe communicating the outlet of the radiator 2 and the inlet of the water pump 3.
Thus, the battery pack 1, the radiator 2, the water pump 3, and the expansion tank 4 are connected by a plurality of cooling pipes to form a cooling circuit. Get into after the slow cooling mode, the secondary refrigerant velocity of flow control unit control water pump 3 operation of slow cooling submodule piece, the secondary refrigerant receives the drive of water pump 3, flow and pass through battery package 1 in the cooling tube, get into radiator 2 after taking away the heat that battery package 1 gived off through indirect heat transfer's mode, in radiator 2, the heat of secondary refrigerant obtains giving off of certain degree, the secondary refrigerant leaves behind radiator 2, part flow direction water pump 3, and send back battery package 1 by water pump 3, part inflow expansion tank 4, flow out expansion tank 4 afterwards, flow direction water pump 3, so relapse.
In the present invention, the expansion tank 4 serves to store and defoam the coolant that has absorbed excessive heat and expanded. In the process of repeated heat absorption and heat release, when the temperature of the secondary refrigerant reaches a certain value, the volume of the secondary refrigerant expands, and after part of the secondary refrigerant enters the expansion water tank 4, bubbles generated due to high temperature are released in the expansion water tank 4 and then sent to the water pump 3 again. The cooling circuit formed by the battery pack 1, the radiator 2, the water pump 3 and the expansion water tank 4 is often used in a cooling system of an engine of a fuel automobile, and the detailed arrangement is not described again.
Furthermore, the cooling module further comprises:
the secondary refrigerant inlet temperature detection unit is used for detecting the temperature of the secondary refrigerant before the secondary refrigerant is contacted with the battery pack;
the secondary refrigerant outlet temperature detection unit is used for detecting the temperature of the secondary refrigerant after the secondary refrigerant is contacted with the battery pack;
when the temperature of the secondary refrigerant before or after the secondary refrigerant is contacted with the battery pack is higher than a first temperature, the flow velocity of the secondary refrigerant is controlled to be a first flow velocity by the secondary refrigerant flow velocity control unit;
when the temperature of the secondary refrigerant before or after the secondary refrigerant is contacted with the battery pack is higher than a second temperature, the flow velocity of the secondary refrigerant is controlled to be a second flow velocity by the secondary refrigerant flow velocity control unit;
and when the temperature of the secondary refrigerant before or after the secondary refrigerant is contacted with the battery pack is higher than the third temperature, the secondary refrigerant flow rate control unit controls the flow rate of the secondary refrigerant to be a third flow rate.
The first temperature is 50 ℃, the second temperature is 60 ℃, the third temperature is 80 ℃, the second flow rate value is at least 130% of the first flow rate value, and the third flow rate value is at least 160% of the second flow rate value. In this embodiment, the first flow rate is 6L/min, the second flow rate is 8L/min, and the third flow rate is 10L/min.
The temperature detecting means may acquire data a plurality of times at one point, or may acquire data once at a plurality of points. As described above, because the coolant is measured during the flowing process, and the obtained data has a certain error, it is necessary to measure multiple sets of data to obtain the highest value, so as to ensure the cooling efficiency of the cooling module. In this embodiment, the means for performing temperature detection is to take data many times at a time, and the specific settings of the temperature measurement position and the temperature measurement frequency are flexibly designed by those skilled in the art as needed, and are not described herein.
Furthermore, the cooling system may further include a display module configured to receive the signal sent by the determining module to enter the slow cooling mode, and display the signal after receiving the signal to enter the slow cooling mode. The display content of the display module comprises a notice character that the vehicle enters the slow cooling mode, the display content cannot be cancelled, the display content further comprises a third duration threshold value representing safe time, and counting down is started immediately after the third duration threshold value is displayed. The third time length threshold is the safe time for passengers to escape, and is specifically not less than 5 min.
Further, when the display module receives a signal sent by the judgment module to exit the slow cooling mode, the countdown is stopped.
Furthermore, the cooling system may further include a broadcasting module configured to receive a signal sent by the determining module to enter the slow cooling mode, and broadcast a preset voice content to the inside or the outside of the vehicle. The voice content includes information that the vehicle has entered a slow-cool mode.
In addition, the invention also provides a cooling method for preventing the heat spread of the battery pack, which comprises the following steps:
judging whether the battery pack enters a thermal runaway state or not;
and when the battery pack enters a thermal runaway state, entering a slow cooling mode, and controlling the secondary refrigerant to perform cooling operation on the battery pack through indirect heat exchange.
Further, the step of judging whether the battery pack enters a thermal runaway state comprises the following steps:
when any one of the following conditions is met, judging that the battery pack enters a thermal runaway state:
the temperature of the battery pack or the battery core is greater than a first temperature threshold, the temperature rise rate is not less than a set rate threshold, and the temperature rise rate continuously exceeds a first duration threshold; or
Voltage drop is generated by the voltage of the battery pack or the battery core, the percentage of the drop value in the initial voltage exceeds a set percentage threshold, the temperature rise rate is not less than a rate threshold, and the temperature continuously rises to exceed a first duration threshold; or
The temperature difference between the single battery cell and the battery pack is not smaller than the temperature difference threshold.
Further, when the battery pack enters a thermal runaway state, the battery pack enters a slow cooling mode, and after the step of controlling the secondary refrigerant to perform cooling operation on the battery pack through indirect heat exchange, the method further comprises the following steps:
and the slow cooling mode is not exited until the energy supply module for supplying energy to the cooling module consumes complete electricity.
Further, when the battery pack enters a thermal runaway state, the battery pack enters a slow cooling mode, and after the step of controlling the secondary refrigerant to perform cooling operation on the battery pack through indirect heat exchange, the method further comprises the following steps:
exiting slow cool mode when any of the following conditions are met:
the temperature of the battery pack or the battery core is not greater than a first temperature threshold, and the temperature rise rate is less than a rate threshold and is not continuously increased; and/or
The voltage of the battery pack or the battery cell stops dropping, and the time for stopping dropping is not less than a second duration threshold; and/or
The temperature difference between the single battery cell and the battery pack is smaller than a temperature difference threshold value.
In summary, the invention provides a cooling system and a method for preventing heat spreading of a battery pack, wherein a strategy of definitely entering and exiting a slow cooling mode is adopted, a secondary refrigerant is used for taking away heat of a thermal runaway battery pack, and the secondary refrigerant does not directly contact the battery pack, so that the thermal runaway can be effectively conducted on the battery pack when occurring, further occurrence of large-area thermal runaway is delayed, the escape time of passengers is prolonged, and the battery pack cannot be damaged when misjudgment occurs. In addition, the invention has low space requirement corresponding to equipment, and relates to equipment which has simple structure and is convenient to maintain and can greatly reduce the cost required by the thermal runaway protection scheme.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.
Claims (10)
1. A cooling system for preventing heat spread of a battery pack, comprising:
the detection module is used for collecting thermal runaway judgment parameters;
the judging module is used for judging whether the battery pack is in a thermal runaway state or not according to the thermal runaway judging parameter and sending a signal for entering a slow cooling mode when the battery pack is in the thermal runaway state;
and the cooling module is used for executing cooling operation according to the signal of entering the slow cooling mode, and the cooling operation reduces the temperature of the battery pack or the battery cell through secondary refrigerant filled in the cooling pipe outside the battery pack or the battery cell.
2. The cooling system for preventing heat spread of a battery pack according to claim 1, wherein the detection module includes:
the temperature detection unit is used for detecting the temperature of the battery pack or the battery core;
the voltage detection unit is used for detecting the voltage of the battery pack or the battery cell;
the judging module judges that the battery pack is in a thermal runaway state when the temperature of the battery pack or the battery core is greater than a first temperature threshold, the temperature rise rate is not less than a set rate threshold and the temperature continuously rises to exceed a first time threshold; and/or
The judging module judges that the battery pack is in a thermal runaway state when the voltage of the battery pack or the battery core is reduced, the percentage of a reduction value in the initial voltage exceeds a set percentage threshold, the temperature rise rate is not less than a rate threshold, and the temperature continuously rises to exceed a first duration threshold; and/or
And the judging module judges that the battery pack is in a thermal runaway state when the temperature difference between the single battery cell and the battery pack is not less than the temperature difference threshold.
3. The cooling system for preventing heat spreading of a battery pack according to claim 2, wherein after the determining module sends the signal for entering the slow cooling mode, if the temperature of the battery pack or the battery cell is not greater than the first temperature threshold, and the temperature rising rate is less than the rate threshold and does not continuously rise, the determining module sends the signal for exiting the slow cooling mode; and/or
If the voltage of the battery pack or the battery cell stops decreasing and the time for stopping decreasing is not less than a second duration threshold, the judging module sends a signal for exiting the slow cooling mode; and/or
And if the temperature difference between the single battery cell and the battery pack is smaller than the temperature difference threshold value, the judging module sends a signal for exiting the slow cooling mode.
4. The cooling system for preventing heat spread of a battery pack according to claim 1, wherein the cooling module further comprises:
the secondary refrigerant inlet temperature detection unit is used for detecting the temperature of the secondary refrigerant before the secondary refrigerant is contacted with the battery pack;
the secondary refrigerant outlet temperature detection unit is used for detecting the temperature of the secondary refrigerant after the secondary refrigerant is contacted with the battery pack;
the secondary refrigerant flow rate control unit is used for controlling the flow rate of the secondary refrigerant in the cooling pipe;
when the temperature of the secondary refrigerant before or after the secondary refrigerant is contacted with the battery pack is higher than a first temperature, the secondary refrigerant flow speed control unit controls the secondary refrigerant to flow at a first flow speed;
when the temperature of the secondary refrigerant before or after the secondary refrigerant is contacted with the battery pack is higher than a second temperature, the secondary refrigerant flow rate control unit controls the secondary refrigerant to flow at a second flow rate;
and when the temperature of the secondary refrigerant before or after the secondary refrigerant is in contact with the battery pack is higher than the third temperature, the secondary refrigerant flow velocity control unit controls the flow velocity of the secondary refrigerant to flow at a third flow velocity.
5. The slow-cooling protection system for preventing the heat spread of the battery pack according to claim 4, wherein the second flow rate is at least 130% of the first flow rate, and the third flow rate is at least 160% of the second flow rate.
6. The cooling system for preventing heat spread of a battery pack according to claim 1, further comprising a broadcasting module for receiving a signal for entering a slow cooling mode from the control module and broadcasting a predetermined voice content to the inside or the outside of the vehicle.
7. A cooling method for preventing heat spread of a battery pack, comprising:
judging whether the battery pack enters a thermal runaway state or not;
and when the battery pack enters a thermal runaway state, entering a slow cooling mode, and controlling the secondary refrigerant to perform cooling operation on the battery pack through indirect heat exchange.
8. The cooling method for preventing heat spread of a battery pack according to claim 7, wherein the step of determining whether the battery pack enters a thermal runaway state includes:
when any one of the following conditions is met, judging that the battery pack enters a thermal runaway state:
the temperature of the battery pack or the battery core is greater than a first temperature threshold, the temperature rise rate is not less than a set rate threshold, and the temperature rise rate continuously exceeds a first duration threshold; or
Voltage drop is generated by the voltage of the battery pack or the battery core, the percentage of the drop value in the initial voltage exceeds a set percentage threshold, the temperature rise rate is not less than a rate threshold, and the temperature continuously rises to exceed a first duration threshold; or
The temperature difference between the single battery cell and the battery pack is not smaller than the temperature difference threshold.
9. The cooling method for preventing heat propagation of a battery pack according to claim 7, wherein after the step of controlling the coolant to perform a cooling operation on the battery pack through indirect heat exchange after entering the slow cooling mode when the battery pack enters the thermal runaway state, the method further comprises:
and the slow cooling mode is not exited until the energy supply module for supplying energy to the cooling module consumes complete electricity.
10. The cooling method for preventing heat propagation of a battery pack according to claim 7, wherein after the step of controlling the coolant to perform a cooling operation on the battery pack through indirect heat exchange after entering the slow cooling mode when the battery pack enters the thermal runaway state, the method further comprises:
exiting slow cool mode when any of the following conditions are met:
the temperature of the battery pack or the battery core is not greater than a first temperature threshold, and the temperature rise rate is less than a rate threshold and is not continuously increased; and/or
The voltage of the battery pack or the battery cell stops dropping, and the time for stopping dropping is not less than a second duration threshold; and/or
The temperature difference between the single battery cell and the battery pack is smaller than a temperature difference threshold value.
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