Evaporation and condensation heat dissipation system based on liquid medium

Abstract

The utility model discloses an evaporation and condensation heat dissipation system based on a liquid medium. The condensing plate and the low-boiling-point flame-retardant liquid medicine are arranged in the closed shell; the plurality of battery cell modules are uniformly distributed at the inner bottom of the closed shell, and gaps are formed among the plurality of battery cell modules; the condensation plate is fixed at the inner top of the closed shell and covers the positions of the plurality of battery cell modules; the inner bottom of the closed shell is filled with the low-boiling-point flame-retardant liquid medicine, and the low-boiling-point flame-retardant liquid medicine intrudes into gaps among the battery cell modules; the low-boiling-point flame-retardant liquid medicine is vaporized and ascends when the battery cell modules are heated, and is evaporated and condensed to the lower surface of the condensing plate to form a plurality of naturally falling condensed water drops to dissipate heat of the battery cell modules; the thermal management system of the power battery is improved, the process requirements of the system are reduced, and the cost is reduced; based on the characteristics of the low-boiling-point flame-retardant liquid medicine, accurate and uniform control of the battery temperature is realized, and generation of open fire can be inhibited while the heat conduction efficiency is improved.

Description

Technical Field

[0001] This utility model relates to the field of battery thermal management and fire protection technology. Specifically, this utility model is applied to lithium batteries, and particularly relates to an evaporation-condensation heat dissipation system based on a liquid medium. Background Technology

[0002] The power battery pack plays a crucial role in new energy vehicles, but its heat dissipation methods have some significant drawbacks, including flammability and high cost. The following is a detailed explanation of the shortcomings of existing power battery pack heat dissipation methods:

[0003] (1) Air cooling (wind cooling) uses natural convection or forced convection to remove the heat generated by the battery by air flow. However, although wind cooling does not involve flammable liquids or substances, its heat dissipation efficiency is relatively low. If the battery temperature is too high, it may cause thermal runaway, leading to battery fire, explosion and other safety accidents. Furthermore, wind cooling is low in cost, but its heat dissipation efficiency is also relatively low, which usually makes it difficult to meet the heat dissipation requirements of high-power battery packs. Therefore, the application scenarios of wind cooling are relatively few at present.

[0004] (2) Liquid cooling (liquid cooling) is a common heat dissipation method that uses the circulation of coolant inside the battery pack to remove heat. The coolant is usually a liquid with high thermal conductivity, such as water or ethylene glycol. The coolant itself is not flammable, but if there is a leak or the battery is damaged and the coolant comes into contact with flammable substances inside the battery, it may cause a fire. In addition, if the battery has a problem, the liquid cooling heat dissipation rate is limited, which can easily lead to heat accumulation and may also cause a chain reaction, or even an explosion or fire. Utility Model Content

[0005] The purpose of this invention is to provide an evaporation-condensation heat dissipation system based on a liquid medium to address the aforementioned problems in the prior art, thereby solving all or one of the aforementioned problems in the thermal control management of current power batteries.

[0006] To solve the above-mentioned technical problems, the specific technical solution of this utility model is as follows:

[0007] This utility model provides an evaporative condensation heat dissipation system based on a liquid medium, connected to an evaporator and a PTC heating module. The evaporator is connected to a vehicle condenser, and includes:

[0008] A sealed housing, a condenser plate disposed within the sealed housing, and a low-boiling-point flame-retardant liquid;

[0009] The sealed housing is used to support a plurality of battery cell modules; the plurality of battery cell modules are evenly distributed at the bottom of the sealed housing, and there are gaps between the plurality of battery cell modules, and the connection ends of the plurality of battery cell modules are all arranged downwards.

[0010] The condenser plate is fixed to the inner top of the sealed housing and covers the positions of several of the battery cell modules;

[0011] The low-boiling-point flame retardant liquid fills the inner bottom of the sealed shell, and the low-boiling-point flame retardant liquid submerges the connection ends of the battery cell modules and penetrates the gaps between the battery cell modules; the low-boiling-point flame retardant liquid is used to vaporize and rise when the battery cell modules are heated, and evaporate and condense on the lower surface of the condenser plate to form a number of condensate droplets; the number of condensate droplets are used to fall naturally onto the battery cell modules to dissipate heat from the battery cell modules.

[0012] The evaporator is located at the top outside the sealed shell, and the PTC heating module is located at the bottom outside the sealed shell. The evaporator is used to exchange heat with the condenser plate, and the PTC heating module is used to heat the low-boiling-point flame retardant liquid.

[0013] In one embodiment of this utility model, the low-boiling-point flame retardant liquid is perfluorohexanone fire extinguishing agent.

[0014] In one embodiment of this utility model, the condenser plate is made of an integrally designed aluminum plate.

[0015] As one embodiment of this utility model, a vent hole communicating with the interior of the sealed shell is provided on the outer top of the sealed shell, and a removable plug is installed on the vent hole.

[0016] In one embodiment of this utility model, several battery cell modules are fixed to the inner bottom of the sealed housing by means of glue injection or pressure plate connection. Each battery cell module has a connecting piece, positive and negative electrodes and their positive and negative connecting wires and solder points at the connection end.

[0017] In one embodiment of this utility model, the perfluorohexanone fire extinguishing agent is in liquid form at room temperature and accumulates at the bottom of the sealed shell at the positions corresponding to several of the battery cell modules.

[0018] In one embodiment of this utility model, the evaporator is connected to the vehicle condenser via a pipeline, and the connection point between the pipeline and the vehicle condenser is located at the position after the vehicle condenser has undergone high-pressure drying; an electronic throttle valve is provided on the pipeline.

[0019] The PTC heating module is used to heat the low-boiling-point flame retardant liquid, thereby causing the low-boiling-point flame retardant liquid to actively evaporate and condense.

[0020] As one embodiment of this utility model, temperature sensors are provided at the bottom of the sealed housing, the inner sidewall of the sealed housing, the condenser plate, and the outside of the sealed housing.

[0021] The temperature sensor at the bottom of the sealed housing is used to monitor the temperature of the low-boiling-point flame retardant liquid. The temperature sensor on the inner sidewall of the sealed housing is installed at the position corresponding to several of the battery cell modules, and the temperature sensor on the inner sidewall of the sealed housing is used to monitor the temperature of several of the battery cell modules. The temperature sensor at the condenser plate is used to monitor the temperature of the condenser plate. The temperature sensor on the outside of the sealed housing is used to monitor the ambient temperature.

[0022] As one embodiment of this utility model, the low-boiling-point flame retardant liquid further includes: a liquid flame retardant medium with a boiling point below 50 degrees and capable of absorbing heat and evaporating.

[0023] As one embodiment of this utility model, the sealed housing is also used as a battery pack housing for electric vehicles;

[0024] The low-boiling-point flame retardant liquid is immersed to a height of 2-3 cm in the sealed shell.

[0025] The beneficial effects of this utility model's technical solution are:

[0026] 1. The low-boiling-point flame retardant liquid used in this solution has the characteristics of fire extinguishing / insulation / flame retardant. While dissipating heat, it can also suppress the occurrence of fire at the first time. Therefore, this low-boiling-point flame retardant liquid can reduce or avoid the occurrence of fire when the battery is short-circuited, effectively control the generation of open flame, extend the rescue time, and minimize the loss of life and property.

[0027] 2. The low-boiling-point flame retardant liquid used in this solution has high heat transfer efficiency, which can reduce energy consumption. Moreover, the low-boiling-point flame retardant liquid itself is non-polluting and harmless to humans, and has extremely high safety.

[0028] 3. The application of this solution can reduce the process requirements of the power battery thermal control management system, reduce the number of parts, and reduce costs.

[0029] 4. This solution can make the overall battery temperature uniform, avoiding local temperature runaway caused by unevenness and reducing the occurrence of local battery problems.

[0030] 5. This solution enables precise control of battery temperature, reduces the formation of lithium dendrites that affect battery life, and extends the service life of the power battery. Attached Figure Description

[0031] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0032] Figure 1 This is a perspective structural diagram of an evaporation-condensation heat dissipation system based on a liquid medium according to this utility model.

[0033] The markings in the attached diagram are explained as follows: 1. Sealed shell; 2. Condensing plate; 3. PTC heating module; 4. Battery cell module; 5. Low boiling point flame retardant liquid; 6. Evaporator. Detailed Implementation

[0034] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the scope of protection of the present invention.

[0035] In the description of this utility model, it should be noted that the embodiments described in this utility model are only some embodiments of this utility model, not all embodiments; based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0036] In the description of this utility model, it should be understood that the terms "upper", "lower", "outer", "inner", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0037] In this utility model, unless otherwise expressly specified and limited, the terms "installation," "connection," "fixation," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, apparatus, product, or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or devices.

[0038] It should be noted that in the description of this utility model:

[0039] PTC is an abbreviation for Positive Temperature Coefficient, which means a positive temperature coefficient. It generally refers to semiconductor materials or components with a large positive temperature coefficient. Usually, when we mention PTC, we mean positive temperature coefficient thermistor, or PTC thermistor for short.

[0040] Perfluorohexanone (PERFLUORO) is a colorless, odorless, and transparent liquid at room temperature. It is easily vaporized and has the molecular formula C6F12O and a boiling point of 49℃. The new clean perfluorohexanone 1230 fire extinguishing agent is a new generation of environmentally friendly clean fire extinguishing agent that is transparent, colorless, odorless, and insulating.

[0041] In thermal management, negative control represents cooling and positive control represents heating. Its zero point depends on the characteristics of the power battery and is a floating value.

[0042] Heat of vaporization is the amount of heat required to evaporate one mole of a substance at a given temperature; for any given substance, it is a function of temperature.

[0043] Vapor pressure, short for saturated vapor pressure, is the pressure exerted by gas molecules on the walls of a container or other materials during the evaporation of a liquid or the sublimation of a solid.

[0044] This embodiment provides an evaporative condensation heat dissipation system based on a liquid medium. It employs a physical method of vaporization for heat transfer, evaporative cooling, and recirculation to achieve heat conduction and exchange. Figure 1 As shown, the system includes: a sealed housing 1, a condenser plate 2 disposed inside the sealed housing 1, and a low-boiling-point flame retardant liquid 5;

[0045] The sealed housing 1 is used to carry several battery cell modules 4 and also serves as the battery pack housing for electric vehicles. In another embodiment, a vent hole communicating with the interior of the sealed housing 1 is provided on the outer top of the sealed housing 1. A removable plug is installed on the vent hole to support the opening or closing of the sealed cavity in the sealed housing 1.

[0046] A plurality of battery cell modules 4 are evenly distributed at the bottom inner side of the sealed housing 1. The plurality of battery cell modules 4 are fixed at the bottom inner side of the sealed housing 1 by means of glue injection or pressure plate connection. Each battery cell module 4 includes a connecting piece, positive and negative electrodes and their positive and negative connecting wires and solder joints at the connection end. There is a gap between the plurality of battery cell modules 4. The connection ends of the plurality of battery cell modules 4 are all arranged downwards. It should be noted that currently, the BMS and its positive and negative connecting wires, solder joints and connecting plates are mostly located at the top. In this application, they are inverted.

[0047] The condenser plate 2 is fixed to the inner top of the sealed housing 1 and covers the positions of several of the battery cell modules 4. The condenser plate 2 is made of an integrally designed aluminum plate.

[0048] A low-boiling-point flame retardant liquid 5 is filled into the inner bottom of the sealed shell 1, and the low-boiling-point flame retardant liquid 5 covers the connection ends of the battery cell modules 4 and penetrates into the gaps between the battery cell modules 4. The low-boiling-point flame retardant liquid 5 is used to perform evaporation and condensation when the battery cell modules 4 are heated. During the evaporation and condensation process, the low-boiling-point flame retardant liquid 5 vaporizes and rises, and condenses on the lower surface of the condenser plate 2 to form a number of condensate droplets. The condensate droplets fall naturally onto the battery cell modules 4 to dissipate heat. During the heat dissipation process, as the condensate droplets vaporize and evaporate again, a cyclical evaporation and condensation heat dissipation effect is achieved.

[0049] In one embodiment of this utility model, in order to simultaneously achieve heat conduction and fire extinguishing functions, the low-boiling-point flame retardant liquid 5 is a perfluorohexanone fire extinguishing agent. Due to the characteristics of the low-boiling-point flame retardant liquid 5, it is a liquid at room temperature and can be stored at normal atmospheric pressure. Since its heat of vaporization is only 1 / 25 of that of water, while its vapor pressure is 25 times that of water, and its boiling point is only 49 degrees Celsius, these properties make it easy to vaporize and exist in a gaseous state. It mainly relies on heat absorption to achieve the fire extinguishing effect. In another embodiment, the low-boiling-point flame retardant liquid 5 can also be a liquid flame retardant medium with a boiling point below 50 degrees Celsius that can absorb heat and evaporate.

[0050] It should be noted that the low-boiling-point flame retardant liquid 5 in this application is in liquid form and accumulates in the lower shell at room temperature, and the liquid surface of the perfluorohexanone fire extinguishing agent covers the connection end of the battery cell module 4 and penetrates into the gap between the battery cell modules 4; the battery cell is in direct contact with the low-boiling-point flame retardant liquid 5, and part of the battery cell is immersed in the low-boiling-point flame retardant liquid 5, so as to achieve extensive temperature control or even constant temperature control of the battery within a very precise range;

[0051] It should also be noted that the filling base of the low-boiling-point flame retardant liquid 5 is: the minimum design percentage of the total volume in the battery pack, plus the remaining space volume after subtracting the volume occupied by the cell module 4 from the total volume; take the larger value or according to the immersion requirements, and immerse the battery in a concentration of not less than 6% of the design concentration.

[0052] Reference formula: G = K**C / (100 - C);

[0053] Fire extinguishing design dosage or inerting design dosage = altitude correction factor * ratio of net volume of protected area to mass volume of superheated agent vapor at standard atmospheric pressure and lowest ambient temperature of protected area * fire extinguishing design concentration or inerting design concentration.

[0054] G – Fire extinguishing design dosage or inerting design dosage (kg)

[0055] C – Fire extinguishing design concentration or inerting design concentration (minimum 6%-10%)

[0056] S—Mass volume of superheated extinguishing agent vapor at 101 kPa atmospheric pressure and minimum ambient temperature of the protected area (m³) 3 / kg)

[0057] V – Net volume of the protected area (m³) 3 )

[0058] K – Altitude correction factor.

[0059] It should also be noted that the immersion height of the low-boiling-point flame retardant liquid 5 in the sealed shell 1 is usually 2 to 3 centimeters.

[0060] In one embodiment of this utility model, the sealed housing 1 is divided into an outer shell body, an upper shell connected to the top of the outer shell body, and a lower shell connected to the bottom of the outer shell body. The upper shell, the outer shell body, and the lower shell are connected to each other and form a sealed space. The condenser plate 2 is fixed to the top of the upper shell. The upper shell, the outer shell body, and the lower shell are either separately arranged or integrally arranged.

[0061] It should be noted that, based on the characteristics of the low-boiling-point flame retardant liquid 5 mentioned above, this lower shell was designed. The function of the lower shell is to serve as a liquid pool for the low-boiling-point flame retardant liquid 5. On this basis, a small amount of low-boiling-point flame retardant liquid 5 can be stored at the bottom of the power battery. During operation, the battery cells are immersed in or partially immersed in the low-boiling-point flame retardant liquid 5. The gaps between the batteries are used as channels for the upward movement of gaseous molecules, so that the vaporized low-boiling-point flame retardant liquid 5 eventually accumulates on the condenser plate 2 at the top of the power battery, keeping it in a balanced state with the highest content of gaseous molecules. This can maintain a specific temperature and achieve constant temperature control.

[0062] As one embodiment of this utility model, considering the extreme usage scenarios of this system, the system also includes an evaporator 6, a PTC heating module 3, and a temperature sensor. The functions of these modules are described in detail below:

[0063] (1) Evaporator 6:

[0064] During high-power charging and discharging, the cell temperature rises rapidly, causing a large amount of low-boiling-point flame retardant liquid 5 to vaporize, increasing its evaporation pressure and gaseous molecular weight. Maintaining this state for a long time will lead to a decrease in heat exchange efficiency. To solve this problem, an evaporator 6 is installed on the top of the upper casing, and the evaporator 6 exchanges heat with the condenser plate 2. The top of the battery is designed with the original vehicle air conditioning system condenser, and the evaporator 6 is connected to the original vehicle condenser through a pipe. The connection point of the pipe to the vehicle condenser is located at the position after the high-pressure drying of the vehicle condenser. An electronic throttle valve is installed on the pipe. The addition of the original vehicle air conditioning system can exchange heat to the outside of the power battery or the outside of the vehicle body, ultimately keeping the battery at an ideal operating temperature.

[0065] It should be noted that the vehicle air conditioning system is currently standard equipment in electric vehicles. The working principle of the condenser in the vehicle air conditioning system is as follows: the compressor draws in low-pressure vapor from the evaporator 6, increases its pressure, and sends it to the condenser, where it condenses into a higher-pressure liquid. After being throttled by the expansion valve, it becomes a lower-pressure liquid and is sent back to the evaporator 6, where it absorbs heat and evaporates into lower-pressure vapor, which is then sent back to the compressor, thus completing the refrigeration cycle. Therefore, based on this principle, this solution connects the original vehicle air conditioning system in series and parallel to form a pipeline. A parallel pipeline is connected from the location after the high-pressure drying of the original condenser, passing through an electronic expansion valve to the evaporator 6 on top of the battery pack. The evaporator 6 exchanges heat with the condensing metal plate inside the top of the battery pack. Because this solution "has the original vehicle air conditioning system condenser at the top of the battery, and the evaporator 6 is connected to the original condenser via a pipeline, the connection point between the pipeline and the vehicle condenser is located at the location after the high-pressure drying of the vehicle condenser." The pipeline is equipped with an electronic throttle valve, which is equivalent to the above working principle where "the liquid is condensed into a higher pressure liquid in the condenser. After being throttled by the throttle valve, it becomes a lower pressure liquid and is then sent to the evaporator 6". This enables the evaporator 6 to actively exchange heat with the condensing metal plate on the top of the battery pack under the drive of the vehicle's air conditioning system. This allows the evaporator 6 to improve the efficiency of water droplet condensation on the condensing metal plate, thus addressing the problem of increased evaporation pressure of the low-boiling-point flame retardant liquid 5 under the condition of rapid temperature rise of the battery cell during high-power charging and discharging. The start-up and regulation of the electronic throttle valve and the air conditioning system, i.e., the cooling intensity, are controlled by the start-up and shutdown conditions set by the temperature monitoring system inside the battery pack.

[0066] It should also be noted that metal-cased battery packs are currently a trend in passenger vehicles. The condenser can be a traditional rectangular or irregular shape, but it must be a homogeneous cooling condenser, represented by a parallel flow form. This design, which relies on contact conduction of temperature, facilitates battery replacement or swapping. The condenser can also be made directly into a sealed cover at the top of the battery pack, which is extremely efficient, but the disadvantage is that it cannot be swapped quickly.

[0067] (2) PTC heating module 3:

[0068] The PTC heating module 3 is installed on the bottom of the lower housing. Specifically, the PTC heating module 3 is connected to the bottom of the lower housing by a plug-in connection. When the ambient temperature or the cell temperature does not meet the design requirements, it is necessary to raise the temperature. The PTC heating module 3 directly conducts heat to the low-boiling-point flame retardant liquid 5. Due to the characteristics of the low-boiling-point flame retardant liquid 5, it will quickly absorb heat and evaporate, and quickly and evenly distribute the heat through the contact of the immersed part and through the gaps between the cell modules 4, reaching the design temperature range in a very short time. Of course, as another implementation method, the PTC heating module 3 can also be clipped onto the metal heat sink plate at the bottom of the battery pack.

[0069] (3) Temperature sensor:

[0070] To obtain comprehensive temperature data, temperature sensors are provided at the bottom of the sealed housing 1, the inner wall of the sealed housing 1, the condenser plate 2, and the outside of the sealed housing 1. The temperature sensor at the bottom of the sealed housing 1 is used to monitor the temperature of the low-boiling-point flame retardant liquid 5. The temperature sensor on the inner wall of the sealed housing 1 is installed at the positions corresponding to several of the battery cell modules 4, and the temperature sensor on the condenser plate 2 is used to monitor the temperature of the condenser plate 2. The temperature sensor on the outside of the sealed housing 1 is used to monitor the ambient temperature. When the ambient temperature measured by the vehicle's external temperature sensor is lower than the battery pack design temperature, the parameters are checked against the table and compared with the temperature sensor value inside the battery pack. The preheating program is started, and the PTC heating module 3 is turned on. When the temperature sensor inside the battery pack measures that the design temperature has been reached, the preheating is disconnected. When the temperature sensor inside the battery pack measures that the working design parameters have been exceeded, the air conditioning cooling system is started to cool the temperature through evaporation, sensible heat, and heat displacement, thereby achieving the purpose of temperature control and cooling, and realizing the locking of the design temperature range value during low and high temperature regulation and switching.

[0071] In summary, based on the actual application scenarios of this utility model, the working principle will be further explained as follows:

[0072] Negative control: When the cell temperature rises rapidly due to high-power charging and discharging, the cell or module directly exchanges heat with the low-boiling-point flame retardant liquid 5, causing it to quickly reach evaporation conditions. The liquid then rises through the gaps between the cells or modules to the top condenser plate 2 of the battery pack. The vaporized low-boiling-point flame retardant liquid 5 rapidly condenses and accumulates upon cooling, dripping onto the upper part of the cell or module. The dripping portion, due to the high surface temperature of the cell or module, vaporizes again, reaching the condenser plate 6 for further heat exchange. Plate 2 condenses and drips again, and exchanges heat with the cells or modules to reach a saturated evaporation state, thereby keeping the temperature constant or close to a specific temperature range. During the repeated heat exchange, vaporization, condensation and liquefaction process, excess low-boiling-point flame retardant liquid 5 is collected in the liquid pool at the bottom of the battery pack through the gaps between the cells or modules. In this way, the heat generated during high-power charging and discharging can be rapidly evaporated and vaporized for heat exchange, thereby controlling the temperature of the power battery. It can accurately control the temperature, suppress the formation of lithium dendrites, extend its service life, and reduce the occurrence of short circuit fires.

[0073] Positive control: When the battery cells need to be heated at low temperatures to keep the battery above 20°C, the PTC heating module 3 is activated based on the values ​​collected by the external temperature sensor and the internal temperature sensor of the battery pack. This directly acts on the low-boiling-point flame retardant liquid 5 at the bottom of the battery pack. The low-boiling-point flame retardant liquid 5 has an extremely fast heat absorption and conduction speed, and quickly evaporates and vaporizes to reach a saturated evaporation state, so that the temperature is rapidly and evenly transferred to the entire battery pack, thereby achieving the preheating effect.

[0074] Through the positive and negative control methods described above, the entire battery pack forms a closed and cyclical heat dissipation system based on the low-boiling-point flame retardant liquid 5. When the heat dissipation conditions are met, the low-boiling-point flame retardant liquid 5 automatically evaporates to the condenser plate 2 to form dense water droplets. The water droplets drip down to cool the cell module 4. At the same time, after cooling down, the dripping water droplets gather again to become the low-boiling-point flame retardant liquid 5 for the next "evaporative heat dissipation". This cycle has high heat dissipation efficiency and low heat dissipation cost, while being safe, reliable and flame retardant.

[0075] In this embodiment, the existing power battery thermal management system is improved through the above structural design, which reduces the system process requirements and costs. Based on the unique structure of the thermal management system and the characteristics of the low-boiling-point flame retardant liquid, the battery temperature can be accurately and uniformly controlled. While improving the heat conduction efficiency, it can also suppress the generation of open flames, making up for the shortcomings of the existing technology and having extremely high application value.

[0076] The above description is merely an embodiment of this utility model and does not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made based on the description and drawings of this utility model, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. An evaporative condensation heat dissipation system based on a liquid medium, characterized in that, include: A sealed housing (1), a condenser plate (2) disposed inside the sealed housing (1), and a low-boiling-point flame retardant liquid (5); The sealed housing (1) is used to carry a plurality of battery cell modules (4); the plurality of battery cell modules (4) are evenly arranged in the inner bottom of the sealed housing (1), and there is a gap between the plurality of battery cell modules (4), and the connection ends of the plurality of battery cell modules (4) are all arranged downward. The condenser plate (2) is fixed to the inner top of the sealed housing (1) and covers the positions of several of the battery cell modules (4); The low-boiling-point flame retardant liquid (5) is filled in the inner bottom of the sealed shell (1), and the low-boiling-point flame retardant liquid (5) covers the connection ends of the battery cell modules (4) and penetrates the gaps between the battery cell modules (4); the low-boiling-point flame retardant liquid (5) is used to vaporize and rise when the battery cell modules (4) are heated, and evaporate and condense to form a number of condensate droplets on the lower surface of the condenser plate (2); the number of condensate droplets are used to fall naturally onto the battery cell modules (4) to dissipate heat from the battery cell modules (4).

2. The evaporative condensation heat dissipation system based on a liquid medium according to claim 1, characterized in that: The low-boiling-point flame retardant liquid (5) is perfluorohexanone fire extinguishing agent.

3. The evaporative condensation heat dissipation system based on a liquid medium according to claim 2, characterized in that: The condenser plate (2) is made of an integrally designed aluminum plate.

4. The evaporative condensation heat dissipation system based on a liquid medium according to claim 3, characterized in that: The sealed housing (1) has a vent hole on its outer top that communicates with the interior of the sealed housing (1), and a removable plug is installed on the vent hole.

5. The evaporative condensation heat dissipation system based on a liquid medium according to claim 4, characterized in that: Several of the battery cell modules (4) are fixed to the inner bottom of the sealed housing (1) by means of glue injection or pressure plate connection. Each of the battery cell modules (4) has a connecting piece, positive and negative electrodes and their positive and negative connecting wires and soldering points at the connection end.

6. The evaporative condensation heat dissipation system based on a liquid medium according to claim 5, characterized in that: The perfluorohexanone fire extinguishing agent is in liquid form at room temperature and accumulates at the bottom of the sealed shell (1) at the positions corresponding to several of the battery cell modules (4).

7. The evaporative condensation heat dissipation system based on a liquid medium according to claim 1, characterized in that: An evaporator (6) is provided on the top of the sealed shell (1). The evaporator (6) is used to exchange heat with the condenser plate (2). The evaporator (6) is connected to the vehicle condenser through a pipeline. The connection point between the pipeline and the vehicle condenser is located after the vehicle condenser has been under high pressure and dried. An electronic throttle valve is provided on the pipeline. The bottom of the sealed shell (1) is also provided with a PTC heating module (3), which is used to heat the low boiling point flame retardant liquid (5) and make the low boiling point flame retardant liquid (5) actively evaporate and condense through heating.

8. The evaporative condensation heat dissipation system based on a liquid medium according to claim 7, characterized in that: Temperature sensors are provided at the bottom of the sealed housing (1), the inner sidewall of the sealed housing (1), the condenser plate (2), and the outside of the sealed housing (1). The temperature sensor at the bottom of the sealed housing (1) is used to monitor the temperature of the low-boiling-point flame retardant liquid (5). The temperature sensor on the inner side wall of the sealed housing (1) is installed at the position corresponding to the battery cell modules (4). The temperature sensor on the inner side wall of the sealed housing (1) is used to monitor the temperature of the battery cell modules (4). The temperature sensor at the condenser plate (2) is used to monitor the temperature of the condenser plate (2). The temperature sensor on the outside of the sealed housing (1) is used to monitor the ambient temperature.

9. The evaporative condensation heat dissipation system based on a liquid medium according to claim 1, characterized in that: The sealed housing (1) is also used as the battery pack housing for electric vehicles.

10. The evaporative condensation heat dissipation system based on a liquid medium according to claim 1, characterized in that: The immersion height of the low-boiling-point flame retardant liquid (5) in the sealed shell (1) is 2-3 cm.

Images