Energy storage system thermal management method, battery device, energy storage system and electric equipment

Abstract

The application relates to a heat management method of an energy storage system, a battery device, an energy storage system and a power utilization device, and relates to the technical field of energy storage. In the application, a liquid cooling plate of the battery device can include a main flow channel and an extension flow channel in communication. The main flow channel is located below a battery assembly, and the extension flow channel is not located below the battery assembly. The refrigerant in the main flow channel of the liquid cooling plate can absorb heat of the battery assembly, so that the refrigerant changes from a liquid phase to a gas-liquid two-phase flow, and then the refrigerant flows from the main flow channel into the extension flow channel. The refrigerant in the extension flow channel can absorb heat from a heat source other than the battery assembly, so that the refrigerant changes from the gas-liquid two-phase flow to a gas phase with superheat. In the arrangement, the heat dissipation efficiency of the battery assembly is relatively high.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of energy storage, and in particular to a heat management method of an energy storage system, a battery device, an energy storage system and an electrical equipment. BACKGROUND

[0002] In the related art, an energy storage system includes a battery device, a compressor, a condenser and a throttle valve, the battery device includes a battery assembly and a liquid cooling plate, the liquid cooling plate, the compressor, the condenser and the throttle valve are connected through pipelines to form a heat dissipation loop, a refrigerant circulates in the heat dissipation loop, and the refrigerant located in the liquid cooling plate can absorb heat of the battery assembly in a working state, so that the working temperature of the battery assembly does not exceed a safety upper limit value. In the related art, the heat dissipation efficiency of the battery assembly needs to be improved. SUMMARY

[0003] The present application provides a heat management method of an energy storage system, a battery device, an energy storage system and an electrical equipment, which can improve the heat dissipation efficiency of the battery assembly.

[0004] In a first aspect, the present application provides a heat management method of an energy storage system, the energy storage system including a battery device, the battery device including a liquid cooling plate and a battery assembly, the liquid cooling plate being provided with a flow channel, the flow channel being used for flowing a refrigerant, the flow channel including a main flow channel and an extension flow channel connected in series, an outer structural wall of the main flow channel being in contact with the battery assembly, an outer structural wall of the extension flow channel being away from the battery assembly, the heat management method of the energy storage system including: causing the refrigerant located in the main flow channel to absorb heat of the battery assembly, so that the refrigerant changes from a liquid phase to a gas-liquid two-phase flow, causing the refrigerant to flow from the main flow channel into the extension flow channel, and causing the refrigerant located in the extension flow channel to absorb heat from a heat source other than the battery assembly, so that the refrigerant changes from the gas-liquid two-phase flow to a gas phase with superheat.

[0005] Optionally, the heat management method of the energy storage system further includes: presetting a mass flow rate q of the refrigerant before driving the refrigerant to flow, and adjusting the heat generation power P PTC of the heat generation component according to the mass flow rate q first, and then adjusting the mass flow rate q according to the heat generation power P PTC of the heat generation component.

[0006] Optionally, the extension flow channel includes a start portion and an end portion, the start portion being closer to the end of the main flow channel than the end portion, and the method of adjusting the heat generation power P PTC of the heat generation component according to the mass flow rate q includes: obtaining a volume fraction V l of the liquid phase included in the gas-liquid two-phase flow located in the start portion, obtaining a pressure P of the gas-liquid two-phase flow located in the start portion, obtaining an initial temperature T c of the gas-liquid two-phase flow located in the start portion, and obtaining a superheat temperature T g, the volume fraction V l , the initial temperature T c , the superheat temperature T g , and the mass flow rate q to adjust the heat generation power P PTC .

[0007] Optionally, the method for adjusting the mass flow rate q further according to the heat generation power P PTC includes: adjusting the mass flow rate q according to the obtained heat generation power P PTC , the superheat temperature T g , and the pressure P.

[0008] Optionally, the method for obtaining the volume fraction V l of the liquid phase included in the gas-liquid two-phase flow located at the initial section includes: obtaining the volume fraction V l by using at least one of a capacitive sensor, an optical fiber sensor, and an ultrasonic sensor.

[0009] Optionally, the method for obtaining the pressure P of the gas-liquid two-phase flow located at the initial section includes: obtaining the pressure P by using at least one of a piezoresistive sensor, a piezoelectric sensor, and a capacitive sensor.

[0010] Optionally, the method for obtaining the initial temperature T c of the gas-liquid two-phase flow located at the initial section includes: obtaining the initial temperature T c by using at least one of a thermocouple sensor, a thermal resistance sensor, and a thermistor sensor, and / or the method for obtaining the superheat temperature T g of the gas phase with superheat located at the end section includes: obtaining the superheat temperature T g by using at least one of a thermocouple sensor, a thermal resistance sensor, and a thermistor sensor.

[0011] In a second aspect, the present application provides a battery device, which comprises a liquid cooling plate and a battery assembly, the liquid cooling plate is provided with a flow channel, the flow channel is used for circulating refrigerant, the flow channel comprises a main flow channel and an extension flow channel connected in series, the outer structural wall of the main flow channel is in contact with the outer structural wall of the battery assembly, the outer structural wall of the extension flow channel is away from the outer structural wall of the battery assembly, and the extension flow channel is used for conducting heat from a heat source outside the battery assembly to the refrigerant.

[0012] Optionally, the battery device further comprises a heating element, which is arranged on the outer structural wall of the extension flow channel or in the extension flow channel. Optionally, the heating element comprises an electric heating element.

[0013] Optionally, the extension flow channel further comprises an initial section and an end section, the initial section is located close to the end of the main flow channel relative to the end section, and the battery device further satisfies at least one of the following arrangements:

[0014] Setting (a): the battery device comprises an ultrasonic sensor, the ultrasonic sensor is arranged on the outer structural wall of the initial portion, and the ultrasonic sensor detects the volume fraction V of the liquid phase of the refrigerant located in the initial portion l .

[0015] Setting (b): the battery device comprises a pressure sensor, the pressure sensor is arranged in the initial portion, and the pressure sensor detects the pressure P of the refrigerant located in the initial portion.

[0016] Setting (c): the battery device comprises a first temperature sensor, the first temperature sensor is arranged in the initial portion, and the first temperature sensor detects the initial temperature T of the refrigerant located in the initial portion c .

[0017] Setting (d): the battery device comprises a second temperature sensor, the second temperature sensor is arranged in the terminal portion, and the second temperature sensor detects the superheat temperature T of the refrigerant located in the terminal portion g .

[0018] Optionally, the flow passage area of the extension flow channel is greater than the flow passage area of the main flow channel.

[0019] Optionally, the outer structural wall of the main flow channel is in contact with the bottom wall of the battery assembly.

[0020] Optionally, the battery device comprises a cover, the cover covers the battery assembly, the cover covers at least part of the structure of the top of the outer structural wall of the extension flow channel, or the cover does not cover the top of the outer structural wall of the extension flow channel.

[0021] Optionally, the extension direction of the main flow channel and the extension direction of the extension flow channel are parallel or intersected.

[0022] In a third aspect, the present application provides a storage energy system, which can be used to execute the thermal management method of the storage energy system described above, or the storage energy system can comprise the battery device described above.

[0023] In a fourth aspect, the present application provides a power consumption device, which comprises the battery device described above.

[0024] In the present application, the refrigerant located in the main flow channel is not completely gasified in the process of absorbing the heat generated by the battery assembly, and some liquid phase is still included in the refrigerant located at the end of the main flow channel when the refrigerant flows to the end of the main flow channel. Since the specific heat capacity of the liquid phase is relatively larger than that of the gas phase, the liquid phase located at the end of the main flow channel can still absorb relatively more heat per unit time, so that the heat dissipation efficiency of the battery monomer near the end of the main flow channel in the battery assembly is relatively large, thereby the difference degree between the temperature of some battery monomers in the battery assembly is relatively small. Accordingly, the difference degree between the attenuation amplitude of the capacity of some battery monomers in the battery assembly is relatively small, the difference degree between the increase amplitude of the internal resistance of some battery monomers in the battery assembly is relatively small, and the current input capability and the current output capability of the battery assembly as a whole are not easily limited.

[0025] It should be understood that the above general description and the following detailed description are only exemplary and cannot limit the present application. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0027] Figure 1 A cross-sectional structure schematic diagram of the battery device in an embodiment of the present application;

[0028] Figure 2 A connection structure schematic diagram of the liquid cooling plate, the pipeline, the compressor, the condenser and the throttle valve in an embodiment;

[0029] Figure 3 A partial cross-sectional structure schematic diagram of the refrigerant and the liquid cooling plate in an embodiment;

[0030] Figure 4 A partial cross-sectional structure schematic diagram of the refrigerant and the liquid cooling plate in another embodiment;

[0031] Figure 5 A flowchart of the thermal management method of the energy storage system in an embodiment of the present application;

[0032] Figure 6 A connection structure schematic diagram of the liquid cooling plate, the pipeline, the compressor, the condenser, the driving pump and the throttle valve in an embodiment;

[0033] Figure 7FIG. 6 is a schematic view of a partial cross-sectional assembly structure of a liquid cooling plate, an ultrasonic sensor, a pressure sensor, a first temperature sensor, a second temperature sensor, and a heat generating member in one embodiment;

[0034] Figure 8 FIG. 7 is a schematic view of a partial cross-sectional structure of a liquid cooling plate in another embodiment;

[0035] Figure 9 FIG. 8 is a schematic view of a partial cross-sectional structure of a flow channel and a flow guide member in one embodiment;

[0036] Figure 10 FIG. 9 is a schematic view of a partial cross-sectional structure of a flow channel and a flow guide member in another embodiment;

[0037] Figure 11 FIG. 10 is a schematic view of a partial cross-sectional structure of a main flow channel in still another embodiment;

[0038] Figure 12 FIG. 11 is a schematic view of a partial cross-sectional structure of a liquid cooling plate in yet another embodiment;

[0039] Figure 13 FIG. 12 is a schematic view of a partial cross-sectional structure of a liquid cooling plate, a heat generating member, and a heat shield in one embodiment;

[0040] Figure 14 FIG. 13 is a schematic view of a partial cross-sectional structure of a liquid cooling plate, a heat generating member, and a heat shield in another embodiment;

[0041] Figure 15 FIG. 14 is a schematic view of a cross-sectional structure of a battery device according to the present application in another embodiment;

[0042] Figure 16 FIG. 15 is a schematic view of a cross-sectional structure of a battery device according to the present application in still another embodiment;

[0043] Figure 17 FIG. 16 is a schematic view of a cross-sectional structure of a liquid cooling plate in one embodiment;

[0044] Figure 18 FIG. 17 is a schematic view of a cross-sectional structure of a liquid cooling plate in another embodiment.

[0045] BRIEF DESCRIPTION OF THE DRAWINGS

[0046] 10 - battery device, 10a - accommodating cavity, 1 - liquid cooling plate, 11 - flow channel, 111 - main flow channel, 111a - end portion, 111b - spiral guide portion, 112 - extended flow channel, 112a - start portion, 112b - end portion, 112c - liquid storage groove, 112d - protrusion portion, 12 - flow guide member, 13 - partition portion, 2 - battery assembly, 21 - battery cell, 3 - upper cover, 4 - heat generating member, 5 - ultrasonic sensor, 6 - pressure sensor, 7 - first temperature sensor, 8 - second temperature sensor, 9 - heat shield, 9a - accommodating space, 20 - pipeline, 30 - compressor, 40 - condenser, 50 - throttle valve, 60 - refrigerant, 601 - liquid phase, 602 - gas phase, 70 - driving pump. DETAILED DESCRIPTION

[0047] In order to better understand the technical solutions of the present application, the embodiments of the present application are described in detail below in conjunction with the drawings. It should be clear that the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without making creative labor belong to the protection scope of the present application. The terms used in the embodiments of the present application are only for the purpose of describing the specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. It should be understood that the term "and / or" used herein is only to describe the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " in this paper generally represents that the front and rear associated objects are in an "or" relationship.

[0048] In the first aspect, the present application provides some embodiments of the heat management method of the energy storage system, which relates to the technical field of energy storage. In order to facilitate the understanding of the embodiments of the heat management method of the energy storage system described herein, some contents about the structure of the energy storage system are introduced first. Among them, the front-rear direction, the left-right direction and the up-down direction (alias can be called height direction) are marked in the drawings of some embodiments, and each two directions in the front-rear direction, the left-right direction and the up-down direction are perpendicular to each other. Among them, the front-rear direction can also be the first direction, the left-right direction can also be the second direction, and the up-down direction can also be the third direction.

[0049] In some embodiments, the energy storage system can include a battery device (alias battery pack), a compressor, a condenser and a throttle valve, please refer to Figure 1As shown, the battery device 10 can include a liquid cooling plate 1, a battery assembly 2, and an upper cover 3, the upper cover 3 is located above the liquid cooling plate 1, and a containing cavity 10a can be formed by at least the upper cover 3 and the liquid cooling plate 1, and the battery assembly 2 is located in the containing cavity 10a. The battery assembly 2 can include at least two battery monomers 21, and the electrical connection relationship between the two battery monomers 21 can include series connection or parallel connection. If the battery assembly 2 includes three or more battery monomers 21, the electrical connection relationship between the at least three battery monomers 21 can include mixed connection (combination of series connection and parallel connection). The liquid cooling plate 1 is provided with a flow channel 11, and a refrigerant (not shown in the figure) is used to flow in the flow channel 11. During the charging process or the discharging process, the battery assembly 2 will generate heat, and the refrigerant is used to absorb the heat generated by the battery assembly 2, so that the temperature of the battery assembly 2 does not exceed the upper limit value of the normal working temperature range, thereby enabling the battery assembly 2 to work normally and improving the service life of the battery assembly 2. Please refer to Figure 2 As shown, the liquid cooling plate 1 can be connected with a compressor 30 through a pipeline 20, the compressor 30 can be connected with a condenser 40 through the pipeline 20, the condenser 40 can be connected with a throttling valve 50 through the pipeline 20, and the throttling valve 50 can be connected with the liquid cooling plate 1 through the pipeline 20. Under this arrangement, the refrigerant in the flow channel 11 of the liquid cooling plate 1 is vaporized after absorbing the heat generated by the battery assembly 2, so that the refrigerant changes from a low-temperature and low-pressure liquid state to a medium-temperature and low-pressure gas state. The refrigerant in the medium-temperature and low-pressure gas state enters the compressor 30 from the flow channel 11 through the pipeline 20, and the refrigerant is compressed by the compressor 30, so that the refrigerant changes from the medium-temperature and low-pressure gas state to a high-temperature and high-pressure gas state. The refrigerant in the high-temperature and high-pressure gas state enters the condenser 40 from the compressor 30 through the pipeline 20, and the refrigerant releases heat and condenses in the condenser 40, so that the refrigerant changes from the high-temperature and high-pressure gas state to a low-temperature and high-pressure liquid state. The refrigerant in the low-temperature and high-pressure liquid state enters the throttling valve 50 from the condenser 40 through the pipeline 20, and the refrigerant changes from the low-temperature and high-pressure liquid state to a low-temperature and low-pressure liquid state during passing through the throttling valve 50. The refrigerant in the low-temperature and low-pressure liquid state returns to the flow channel 11 of the liquid cooling plate 1 from the throttling valve 50 through the pipeline 20, and the refrigerant returning to the flow channel 11 of the liquid cooling plate 1 continues to absorb the heat generated by the battery assembly 2 to continue the above-mentioned heat cycle process, thereby enabling the battery assembly 2 to be continuously cooled.

[0050] In some embodiments, the refrigerant in the gas state can be referred to as gas phase, the refrigerant in the liquid state can be referred to as liquid phase, and the mixture of the refrigerant in the gas state and the refrigerant in the liquid state can be referred to as gas-liquid two-phase flow.

[0051] In some embodiments, please refer to Figure 1As shown, the flow channel 11 of the liquid cooling plate 1 can include a main flow channel 111 and an extension flow channel 112 in communication, and the refrigerant can flow from the main flow channel 111 to the extension flow channel 112. The main flow channel 111 can be provided with an inlet (not shown in the figure) which can be in communication with the throttling valve 50 through the external pipeline 20, so that the refrigerant in the low-temperature high-pressure liquid state flows from the throttling valve 50 into the main flow channel 111. The extension flow channel 112 can be provided with an outlet (not shown in the figure) which can be in communication with the compressor 30 through the external pipeline 20, so that the refrigerant in the medium-temperature low-pressure gas state flows from the extension flow channel 112 into the compressor 30.

[0052] In some embodiments, referring to Figure 1 and Figure 3 , the outer structural wall of the main flow channel 111 can be in contact with the battery assembly 2, and the heat generated by the battery assembly 2 can be conducted to the refrigerant 60 in the main flow channel 111 through the outer structural wall of the main flow channel 111, so that the refrigerant 60 in the main flow channel 111 vaporizes, in detail, some of the liquid phase 601 changes into the gas phase 602. In the main flow channel 111, the proportion of the liquid phase 601 gradually decreases and the proportion of the gas phase 602 gradually increases along the flow direction of the refrigerant 60, closer to the extension flow channel 112. In brief, in the main flow channel 111, the liquid phase 601 changes into a gas-liquid two-phase flow (including both the liquid phase 601 and the gas phase 602), and the gas-liquid two-phase flow flows from the end of the main flow channel 111 into the extension flow channel 112.

[0053] In some embodiments, referring to Figure 1 , the outer structural wall of the extension flow channel 112 is away from the battery assembly 2, or in other words, the outer structural wall of the extension flow channel 112 does not contact the battery assembly 2. In order to prevent the compressor 30 from easily suffering from the problem of liquid hammering (liquid that is not easy to compress is compressed in the compressor, and a transient high pressure is generated, which can easily damage the compressor), other heat sources (heat sources other than the battery assembly) can be provided on the outer structural wall of the extension flow channel 112, or other heat sources can be provided near the outer structural wall of the extension flow channel 112, and the heat generated by the other heat sources can be conducted to the refrigerant 60 in the extension flow channel 112 through the outer structural wall of the extension flow channel 112 as shown in Figure 4 , so that the liquid phase 601 in the gas-liquid two-phase flow in the extension flow channel 112 continues to absorb heat and vaporize into the gas phase 602. Referring to Figure 4 , when all the liquid phase 601 changes into the gas phase 602, the temperature of the refrigerant 60 at this time is the saturation temperature T s , which means the temperature at which the liquid phase and the gas phase reach a dynamic equilibrium state (i.e., a saturation state) at a certain pressure, and accordingly, the refrigerant 60 at this time can be referred to as saturated gaseous refrigerant (another name can be dry saturated vapor refrigerant). When the temperature of the refrigerant 60 reaches the saturation temperature Ts After that, the refrigerant 60 (pure gas phase 602 excluding liquid phase 601) located in the extended flow passage 112 will continue to absorb heat, and the temperature of the refrigerant 60 will also change from the saturation temperature T s to the superheat temperature T g At this time, the refrigerant 60 can be referred to as superheated gaseous refrigerant, and the refrigerant 60 at this time has a superheat degree T Δ , the superheat degree T Δ is the difference between the superheat temperature T g and the saturation temperature T s , and can also be expressed by the formula T Δ = T g - T s . According to the above, in the process of making the refrigerant 60 located in the extended flow passage 112 absorb heat from the heat source other than the battery assembly 2, the refrigerant 60 changes from gas-liquid two-phase flow to gas phase 602 with superheat degree T Δ . Among them, the unit of the saturation temperature T s and the unit of the superheat temperature T g mentioned above are both Celsius (℃).

[0054] According to the above, please refer to Figure 4 , the refrigerant 60 located in the main flow passage 111 is not completely vaporized in the process of absorbing the heat generated by the battery assembly 2, and when the refrigerant 60 flows to the end of the main flow passage 111 111a (which can also be said to be the part of the main flow passage 111 connected with the extended flow passage 112), the refrigerant 60 at the end of the main flow passage 111 111a still includes some liquid phase 601. Because the specific heat capacity of the liquid phase 601 is relatively larger than that of the gas phase 602, the liquid phase 601 at the end of the main flow passage 111 111a can absorb relatively more heat per unit time, so that the heat dissipation efficiency of the battery monomer 21 (for example, one or more battery monomers 21 on the right side shown in Figure 1 ) near the end of the main flow passage 111 in the battery assembly 2 is relatively large, so that the difference between the temperatures of some battery monomers 21 in the battery assembly 2 is relatively small. Accordingly, the difference between the attenuation amplitudes of the capacities of some battery monomers 21 in the battery assembly 2 is relatively small, the difference between the increase amplitudes of the internal resistances of some battery monomers 21 in the battery assembly 2 is relatively small, and the current input and output capabilities of the battery assembly 2 as a whole are not easily limited.

[0055] In the heat management method of the related art energy storage system, the outer structure wall of the whole flow channel of the liquid cooling plate contacts the battery assembly, that is, the liquid cooling plate does not include the above-mentioned extended section away from the battery assembly. In order to avoid the problem of liquid impact, in the related art, it is necessary to control all parts of the refrigerant to complete the gasification in the flow channel of the liquid cooling plate, that is, to complete the change process from pure liquid phase to pure gas phase, and all parts of the refrigerant located at the end of the flow channel are gas phase with superheat. Since the specific heat capacity of the gas phase is smaller than that of the liquid phase, the heat that can be absorbed by the refrigerant located at the end of the flow channel in unit time is relatively small, so that the heat dissipation efficiency of the battery cells in the battery assembly close to the end of the flow channel is relatively small, thereby the difference between the temperature of some battery cells in the battery assembly is relatively large. Accordingly, the difference between the capacity attenuation amplitude of some battery cells in the battery assembly is relatively large, and the difference between the increase amplitude of the internal resistance of some battery cells in the battery assembly is relatively large, and the battery cells with relatively large attenuation amplitude and relatively large increase amplitude of internal resistance also cause the current input and output capacity of the battery assembly as a whole to be greatly limited.

[0056] Through the above comparison, some embodiments of the heat management method provided by the present application can improve the heat dissipation efficiency of the battery assembly 2, and the difference between the temperature of some battery cells 21 in the battery assembly 2 is relatively small, thereby the current input and output capacity of the battery assembly 2 as a whole is relatively high.

[0057] In some embodiments of the present application, although the heat generating member is used as a kind of energy consuming member to generate heat that can make the gas-liquid two-phase flow change into gas phase 602 with superheat T Δ , according to the above, since the heat dissipation efficiency of the battery cells 21 close to the end 111a of the main flow channel 111 is relatively large, the internal resistance of the battery cells 21 close to the end 111a of the main flow channel 111 is not easy to increase greatly, and the heat generated by the battery cells 21 close to the end 111a of the main flow channel 111 is relatively small, which in turn makes the refrigerant 60 need to absorb relatively less heat in the main flow channel 111, and accordingly, the working energy consumption of the compressor 30 is also relatively small. It can be understood that although the working energy consumption is increased on the heat generating member, the working energy consumption of the compressor 30 is reduced, and more importantly, the relatively low internal resistance will make the charging power loss and the discharge power loss of the battery assembly 2 relatively small, so that some embodiments of the heat management method of the present application have the effect of energy saving.

[0058] In some embodiments, the number of battery cells 21 in the battery assembly 2 that can absorb heat from the refrigerant 60 located at the end 111a can be one or two, or in other words, Figure 1The one or two battery cells 21 at the rightmost side in the middle can absorb heat from the refrigerant 60 at the end 111a. The following content herein mainly describes the end 111a range with an example of "the refrigerant 60 at the end 111a mainly absorbs heat from the one battery cell 21 at the rightmost side in the middle". Figure 1

[0059] In some embodiments, the heat management method can further include the following content: preset the mass flow rate q of the refrigerant 60 before driving the refrigerant 60 to flow, and control the working frequency of the compressor 30 according to the preset value, so that the actual mass flow rate of the refrigerant 60 flowing into the flow channel 11 of the liquid cooling plate 1 meets the preset value. Wherein, the so-called "meets" includes that the actual mass flow rate is the same as the preset value, and the so-called "meets" also includes that there is an allowable error amount between the actual mass flow rate and the preset value, which will not be described here. In addition, the preset mass flow rate q can be an empirical value or an experimental value, so that the refrigerant 60 does not completely gasify into the gas phase 602 after absorbing heat in the main flow channel 111, so that there is still some liquid phase 601 at the end 111a of the main flow channel 111, or in other words, there is gas-liquid two-phase flow at the end 111a of the main flow channel 111, so that the heat dissipation rate of the battery cell 21 (for example, the one or more battery cells 21 at the rightmost side in the middle shown in FIG. 6) close to the end 111a of the main flow channel 111 is relatively large. Figure 1

[0060] In some embodiments, the heat management method can further include the following content: during the process of driving the refrigerant 60 to flow, the heat generation power P of the heat generating component can be adjusted according to the previously preset mass flow rate q PTC , so that the heat generated by the heat generating component can convert the refrigerant 60 located in the extended flow channel 112 from the gas-liquid two-phase flow to the gas phase 602 with the superheat T Δ , so that the compressor 30 is not prone to liquid hammer problem. During the process of the newly flowed refrigerant 60 in the flow channel 11 flowing in the flow channel 11, not only the battery assembly 2 generates heat, but also the heat generating component generates heat, and the heat generated by the battery assembly 2 and the heat generating component both needs to be absorbed by the newly flowed refrigerant 60 in the flow channel 11, so that the newly flowed refrigerant 60 in the flow channel 11 can sequentially complete the change from the liquid phase 601 to the gas-liquid two-phase flow in the main flow channel 111 and the change from the gas-liquid two-phase flow to the gas phase 602 with the superheat T Δ ​​of the gas phase 602, the mass flow rate q needs to be reset. If the mass flow rate q is not reset, it is possible that all parts of the refrigerant 60 with a relatively small mass flow rate complete the gasification in the main flow channel 111 in advance, and the heat dissipation efficiency of the battery cell 21 near the end 111a of the main flow channel 111 is relatively small, and it is also possible that all parts of the refrigerant 60 with a relatively large mass flow rate are still in the liquid phase 601 at the end 111a of the main flow channel 111. In order to prevent the problem of liquid strike of the compressor 30, the heat generation power P PTC needs to be set relatively large, that is, there is a problem of relatively large energy consumption. Therefore, it is necessary to adjust the mass flow rate q again according to the heat generation power P PTC , and control the operating frequency of the compressor 30 according to the new set value of the mass flow rate q, so that the actual mass flow rate of the refrigerant 60 flowing into the flow channel 11 of the liquid cooling plate 1 meets the new set value. After adjusting the mass flow rate q, the heat generation power P PTC is also adjusted again according to the new mass flow rate q, so as to form a closed-loop adjustment process as shown in Figure 5

[0061] wherein the unit of the mass flow rate q mentioned above is kilogram per second (kg / s), and the unit of the heat generation power P PTC is joule per second (J / s) or watt (W).

[0062] ​In some embodiments, at the beginning of the process of driving the refrigerant 60 to flow, although to ensure that the refrigerant 60 will not be completely gasified into the gas phase 602 after absorbing heat in the main flow channel 111, the preset mass flow rate q before driving the refrigerant 60 to flow can be relatively large compared with the initial setting value of the mass flow rate of the refrigerant in the related art. However, according to the above, since the heat dissipation efficiency of the battery monomer 21 near the end of the main flow channel 111 is relatively large, the internal resistance of the battery monomer 21 near the end of the main flow channel 111 is not easy to increase substantially, and the heat generation of the battery cell of the battery monomer 21 near the end of the main flow channel 111 is relatively small, which will make the heat that needs to be absorbed by the refrigerant 60 in the main flow channel 111 relatively small, and accordingly, the mass flow rate of the refrigerant 60 that needs to flow into the main flow channel 111 in the subsequent process can not increase, can not be easy to increase substantially, or can decrease. According to the above, in the related art, the heat dissipation efficiency of the battery monomer near the end of the flow channel is relatively small, the internal resistance of the battery monomer near the end of the flow channel is relatively large, and the heat generation of the battery monomer near the end of the flow channel is relatively large and tends to gradually increase, which causes the mass flow rate of the refrigerant flowing into the flow channel in the subsequent process to be substantially increased and tends to gradually increase. According to the above comparison, the average mass flow rate of the refrigerant in the entire heat dissipation process of the related art is relatively large, and accordingly, the average working energy consumption of the compressor in the related art is relatively large. In some embodiments of the present application, the average mass flow rate of the refrigerant 60 in the entire heat dissipation process is relatively small, and accordingly, the average working energy consumption of the compressor 30 in some embodiments of the present application is relatively low.

[0063] In some embodiments, as shown in FIG. 12, the extended flow channel 112 can include a starting portion 112a and an ending portion 112b, and the starting portion 112a is closer to the main flow channel 111 than the ending portion 112b. In the process of flowing the refrigerant 60 from the main flow channel 111 to the extended flow channel 112, the refrigerant 60 first passes through the starting portion 112a, and then passes through the ending portion 112b. The method of adjusting the heat generation power P of the heat generation member according to the mass flow rate q mentioned above can include: obtaining the volume fraction V of the liquid phase 601 included in the refrigerant 60 (gas-liquid two-phase flow) located at the starting portion 112a, obtaining the pressure P of the refrigerant 60 (gas-liquid two-phase flow) located at the starting portion 112a, obtaining the initial temperature T of the refrigerant 60 (gas-liquid two-phase flow) located at the starting portion 112a, and obtaining the superheated temperature T of the refrigerant 60 (gas phase 602 with superheat T ) located at the ending portion 112b. According to the obtained volume fraction V, pressure P, initial temperature T, and superheated temperature T, the heat generation power P of the heat generation member is adjusted according to the mass flow rate q. PTC l c Δ g l c ​​​​​​​c Superheat temperature T g And mass flow rate q to adjust heating power P PTC .

[0064] Wherein, the initial temperature T c It can refer to the initial temperature value during the temperature change process of the refrigerant 60 flowing within the extended flow channel 112, the superheat temperature T. g It can refer to the final temperature value during the temperature change process of the refrigerant 60 flowing in the extended flow channel 112.

[0065] In addition, the volume fraction V l This represents the ratio of the volume of a component to the total volume of the mixture. Pressure P is measured in Pascals (Pa) or Newtons per square meter (N / m²). 2 ).

[0066] The following sections of this article will explain in detail how to use the obtained volume fraction V l Pressure P, initial temperature T c Superheat temperature T g Adjusting the heating power P with mass flow rate q PTC .

[0067] In some embodiments, please refer to Figure 4 As shown, the refrigerant 60 in the initiation section 112a is a gas-liquid two-phase flow. All the liquid phase 601 in the gas-liquid two-phase flow needs to absorb heat from the heating element to completely vaporize into gas phase 602, in order to prevent liquid slugging in the compressor 30. The more liquid phase 601 there is in the initiation section 112a, the higher the heating power P required by the heating element. PTC The larger the volume, the less liquid phase 601 is in the initial part 112a, and the higher the required heating power P of the heating element. PTC The less, that is, the less liquid phase 601 in the starting part 112a and the less heating power P of the heating element. PTC There is a positive correlation. As mentioned earlier, the liquid phase 601 in the extended flow channel 112 needs to absorb heat in order to raise the temperature of the refrigerant 60 from the initial temperature T. c Rise to saturation temperature T s Then, the refrigerant 60 continues to absorb heat, so that the temperature of the refrigerant 60 increases from the saturation temperature T. s Rise to superheat temperature T g Therefore, at the numerical calculation level, the heating power P of the heating element... PTC At least including the first heating power P PTC1 Second heating power P PTC2 It can also be used in formula P. PTC= P PTC1 +P PTC2 It indicates that the first heating power P PTC1The temperature required to meet the refrigerant 60 is determined by the initial temperature T. c Rise to saturation temperature T s Second heating power P PTC2 The temperature required to meet the refrigerant 60 is determined by the saturation temperature T. s Rise to superheat temperature T g .

[0068] In some embodiments, the volume fraction V can be determined based on the obtained volume fraction. l Pressure P, initial temperature T c The first heating power P is determined by the mass flow rate q. PTC1 Specifically, the volume fraction V of the liquid phase 601 at the starting section 112a is obtained by a sensor. l Due to the density ρ of liquid phase 601 l Known physical properties (inherent physical characteristics of the material, in kilograms per cubic meter or kg / m³) 3 ), can be used to determine the volume fraction V l and density ρ l Multiply to obtain the product X l Alternatively, formula X can be used. l =ρ l ·V l It means that the product X l This represents the mass concentration of liquid phase 601 in the initial section 112a (in kilograms per cubic meter or kg / m³). 3 The pressure P and initial temperature T of the refrigerant 60 (gas-liquid two-phase flow) at the initiation section 112a can also be obtained by sensors. c Using pressure P as the dividend, and initial temperature T c Adding this to the value 273.15 yields the Kelvin θ (in Kelvin or K). The product of Kelvin θ and the gas constant R is then used as the divisor to obtain the density ρ of the gas phase 602 in the initial section 112a. g Alternatively, the formula ρ can be used. g =P / (T c +273.15)R represents, or, using the formula ρ g =P / θ·R. ​​Wherein, the gas constant R is a known physical property parameter, and its unit is joules per molar Kelvin or J / (mol·K). Since the sum of the volume fraction of the gas phase 602 and the volume fraction of the liquid phase 601 in the initial section 112a is 100%, the volume fraction of the gas phase 602 in the initial section 112a is (1-V l ), the volume fraction (1-V l ) and density ρ g Multiply to obtain the product X g Alternatively, formula X can be used. g =ρg (1-V l ) represents the product X g represents the mass concentration of the gas phase 602 at the start portion 112a. The product X l and the product X g are added to obtain the mixed density X m , which can also be represented by the formula X m =X l +X g , the mixed density X m represents the mass per unit volume of the gas-liquid two-phase flow at the start portion 112a. The product X l is used as the dividend, and the mixed density X m is used as the divisor, thereby obtaining the mass fraction Z l of the liquid phase 601, which can also be represented by the formula Z l =X l / (X l +X g ) or by the formula Z l =X l / X m , the mass fraction Z l of the liquid phase 601 reflects the percentage or proportion of the mass of the liquid phase 601 at the start portion 112a relative to the mass of the gas-liquid two-phase flow at the start portion 112a. The mass fraction Z l can be multiplied by the mass flow rate q to obtain the mass flow rate q l of the liquid phase 601 at the start portion 112a, which can also be represented by the formula q l =q·Z l . The mass flow rate q l of the liquid phase 601 can be multiplied by the latent heat of vaporization H l of the liquid phase 601 to obtain the first heat generation power P PTC1 , which can also be represented by the formula P PTC1 =q l ·H l . Among them, the latent heat of vaporization H l of the liquid phase 601 is a known physical property parameter, and the latent heat of vaporization H l represents the heat absorbed per unit mass of the liquid phase 601 to change from the liquid phase to the gas phase at the same temperature, with the unit of J / kg.

[0069] According to the above, the first heat generation power P PTC1 can also be represented by the following formula:

[0070] P PTC1 =H l ·q·ρ l ·V l / (ρ l ·Vl + P(1 - V l ) / (T c + 273.15)R).

[0071] In some embodiments, the second heating power P g may be determined according to the acquired pressure P and the superheat temperature T PTC2 . Specifically, after the pressure P is acquired, the saturation temperature T s may be determined according to a known pressure-saturation temperature table, which will not be described here in detail in view of the disclosure of the related art. After the saturation temperature T s is acquired, the difference between the superheat temperature T g and the saturation temperature T s is taken as the superheat T Δ , which can also be expressed by the formula T Δ = T g - T s . After the superheat T Δ is acquired, the superheat T Δ , the specific heat capacity C g and the mass flow rate q are multiplied, and the resulting product is the second heating power P PTC2 , which can also be expressed by the formula P PTC2= = T Δ · C g · q. The specific heat capacity C g is a known property parameter of the gas phase 602, representing the heat absorbed by per unit mass of substance to raise the temperature by one unit, with the unit of J / (kg·℃).

[0072] According to the above, the second heating power P PTC2 may also be expressed by the formula:

[0073] P PTC2= = (T g - T s ) C g · q.

[0074] In some other embodiments, the heat generated by the heating element can not be 100% absorbed by the refrigerant 60, and part of the heat generated by the heating element can also be absorbed by the extended flow channel 112, and part of the heat generated by the heating element can also be absorbed by the air outside the extended flow channel 112. The heat absorbed by non-refrigerant substances is all loss heat. Therefore, in the numerical calculation level, the heating power P PTC of the heating element can not only include the first heating power P PTC1 and the second heating power P PTC2 , but also the heating power P PTCA third heating power P PTC3 may also be included PTC3 as the heating loss power. Thus, the heating power P PTC of the heating member can also be expressed by the formula P PTC1 =P PTC2+ +P PTC3 When the heating loss power is taken into account, the control of the heating power P PTC of the heating member is more accurate, thereby more reliably preventing the liquid slugging problem of the compressor 30.

[0075] Hereinafter, the method of adjusting the heating power P PTC of the heating member will be mainly described with reference to the formula P PTC1 =P PTC2 +P PTC .

[0076] In some embodiments, the latent heat of vaporization H l of the liquid phase 601 can be in the range of 160000 J / kg to 180000 J / kg, and the latent heat of vaporization H l may specifically be 160000 J / kg, 165000 J / kg, 170000 J / kg, 175000 J / kg, or 180000 J / kg. The density p l of the liquid phase 601 can be in the range of 1100 kg / m 3 to 1300 kg / m 3 , and the density p l may specifically be 1100 kg / m 3 , 1150 kg / m 3 , 1200 kg / m 3 , 1250 kg / m 3 , or 1300 kg / m 3 . The gas constant R of the gas phase 602 can be in the range of 8.310 J / (mol·K) to 8.315 J / (mol·K), and the gas constant R may specifically be 8.310 J / (mol·K), 8.311 J / (mol·K), 8.312 J / (mol·K), 8.313 J / (mol·K), 8.314 J / (mol·K), or 8.315 J / (mol·K). The specific heat capacity C g of the gas phase 602 can be in the range of 900 J / (kg·℃) to 1000 J / (kg·℃), and the specific heat capacity C gSpecifically, it can be 900 J / (kg·℃), 910 J / (kg·℃), 920 J / (kg·℃), 930 J / (kg·℃), 940 J / (kg·℃), 950 J / (kg·℃), 960 J / (kg·℃), 970 J / (kg·℃), 980 J / (kg·℃), 990 J / (kg·℃), or 1000 J / (kg·℃).

[0077] In some embodiments, the heating power P PTC The method for adjusting the mass flow rate q includes the following: according to the obtained heating power P PTC , the superheat temperature T g , and the pressure P to adjust the mass flow rate q. Specifically, the superheat degree T g can be determined according to the obtained superheat temperature T Δ , and the pressure P. The method for determining the superheat degree T Δ has been described above and will not be repeated here. The superheat degree T Δ is multiplied by the specific heat capacity C g of the gas phase 602, and the obtained product H g represents the heat absorbed by unit mass of the gas phase 602 to rise from the saturation temperature T s to the superheat temperature T g . H g is added to the latent heat of vaporization H l of the liquid phase 601, and the obtained sum H represents the heat absorbed by unit mass of the refrigerant 60 to change from the liquid phase 601 to the gas-liquid two-phase flow and then to the gas phase 602 with the superheat degree T Δ . Since the refrigerant 60 needs to absorb the heat generated by the heat generating component, it also needs to absorb the heat generated by the battery assembly 2, so it needs to consider not only the heating power P PTC of the heat generating component, but also the cell heat dissipation power P cf of the battery assembly 2 (in units of J / s or J / s). The sum of the cell heat dissipation power P cf and the heating power P PTC is taken as the dividend, and the sum H is taken as the divisor to obtain the mass flow rate q of the refrigerant 60, which can also be expressed by the formula q=(P cf +P PTC ) / (H l +T Δ C g ), or by the formula q=(P cf +P PTC ) / (H l +H g ).

[0078] wherein the cell heat dissipation power P cfThis is related to the internal resistance, current, and battery capacity of battery module 2. The cell heat dissipation power P can be measured during the charging process of battery module 2 without implementing thermal management. cf The size of the cell heat release power P was measured during the discharge process of battery assembly 2. cf The magnitude of the measured cell heat dissipation power P cf As these are known parameters, in some embodiments of the thermal management methods of this application, it is not necessary to acquire the cell heat dissipation power P in real time. cf .

[0079] In some other embodiments, the refrigerant 60 needs to absorb the heat generated by the heating element and the heat generated by the battery assembly 2. The refrigerant 60 also needs to absorb the heat possessed by the battery assembly 2 itself, which refers to the heat it possesses when the battery assembly 2 is not in operation. Therefore, in addition to considering the heating power P of the heating element mentioned above... PTC The cell heat dissipation power P of battery module 2 cf We also need to consider the heat loss rate P of battery module 2. cs (Units are joules per second or J / s), heat loss rate P cs The heat loss rate P represents the amount of heat lost by battery module 2 to reduce its set temperature value per unit time. cs The mass M (in kilograms) and specific heat capacity C of battery component 2 are affected. c The effects of (units are joules / kg Celsius or J / (kg·℃)) and cooling rate t (units are degrees Celsius / second or ℃ / s) can also be expressed by formula P. cs =M·C c ·t represents the mass flow rate. Therefore, the mass flow rate q can be expressed by the formula q=(P cf +P PTC +P cs ) / (H l +T Δ C g ) can be expressed as q=(P cf +P PTC +P cs ) / (H l +H g This indicates that the heat loss rate P of battery module 2 is considered. cs In this case, the mass flow rate q of refrigerant 60 can be adjusted more accurately.

[0080] Among them, the mass M of battery module 2 and the specific heat capacity C of battery module 2 are... c All of these are known physical properties, and the cooling rate t is a set parameter that can be large or small.

[0081] In addition, since the heat transfer efficiency of the liquid cooling plate 1 is not 100%, a correction coefficient k needs to be added to the calculation formula of the mass flow rate q, and k > 1 is satisfied, so that the refrigerant 60 actually flowing into the flow channel 11 can absorb the preset target heat in unit time, and thus the mass flow rate q can be expressed by the formula q = k (P cf + P PTC + P cs ) / (H l + T Δ C g ).

[0082] Furthermore, since the heat generation efficiency of the heat generating member is not 100%, a correction coefficient m needs to be added to the calculation formula of the mass flow rate q, and m > 1 is satisfied, so that the refrigerant 60 located at the end portion 112b of the extended flow channel 112 has a gas phase 602 with a superheat T Δ , and thus the mass flow rate q can be expressed by the formula q = (P cf + m P PTC + P cs ) / (H l + T Δ C g ).

[0083] In addition, the correction coefficient k and the correction coefficient m can be considered at the same time, and thus the mass flow rate q can be expressed by the formula q = k (P cf + m P PTC + P cs ) / (H l + T Δ C g ).

[0084] In other embodiments, the refrigerant 60 needs to absorb the heat generation amount of the heat generating member, the heat generation amount of the battery assembly 2, and the heat amount possessed by the battery assembly 2 itself, and the refrigerant 60 can also absorb the heat amount possessed by the flow channel 11 itself and the heat amount of the air outside the flow channel 11. Therefore, in addition to the heat generation power P PTC of the heat generating member, the cell heat dissipation power P cf of the battery assembly 2, and the heat loss rate P cs of the battery assembly 2 mentioned above, the heat loss rate P ws (unit: J / s) of the non-battery assembly substance also needs to be considered, and the heat loss rate P ws represents the heat amount that needs to be lost by the non-battery assembly substance to reduce the preset temperature value in unit time. Therefore, the mass flow rate q can be expressed by the formula q = (P cf + P PTC + P cs + P ws ) / (H l + T ΔC g ) or, in formula, q = (P cf + P PTC + P cs + P ws ) / (H l + H g ). In consideration of the heat loss rate P ws of the substance of the non-battery component, the mass flow rate q of the refrigerant 60 can be adjusted more accurately.

[0085] Hereinafter, the method of adjusting the mass flow rate q of the refrigerant 60 is mainly introduced by taking the formula "q = k (P cf + m P PTC + M·C c ·t) / (H l + T Δ C g )" as an example.

[0086] In some embodiments, the specific heat capacity C g of the battery component 2 can be in the range of 900 J / (kg·℃) to 1100 J / (kg·℃), and the specific heat capacity C g may be specifically 900 J / (kg·℃), 950 J / (kg·℃), 1000 J / (kg·℃), 1050 J / (kg·℃), or 1100 J / (kg·℃).

[0087] In some embodiments, according to the above-mentioned need to preset the mass flow rate q of the refrigerant 60 before driving the refrigerant 60 to flow, since the heat generating member is not started at the preset mass flow rate q, the value of the correction coefficient m can be taken as zero, and the value of T Δ may be taken as zero, and accordingly, the preset mass flow rate q can be represented by the formula "q = k (P cf + M·C c ·t) / H l ".

[0088] In some embodiments, during the process of driving the refrigerant 60 to flow, the above-mentioned correction coefficient m and correction coefficient k can be changed to correct the mass flow rate q of the refrigerant 60.

[0089] In some embodiments, the method of obtaining the liquid phase 601 included in the gas-liquid two-phase flow located at the starting portion 112a can include: obtaining the volume fraction V l of the liquid phase 601 by using at least one sensor of a capacitive sensor, an optical fiber sensor, and an ultrasonic sensor.

[0090] The principle of obtaining the volume fraction V l of the liquid phase 601 by using the capacitive sensor is that the volume fraction Vl The magnitude of the capacitance value can affect the dielectric constant of the medium between the capacitor plates, thus affecting the capacitance value. By detecting changes in the capacitance value, the volume fraction V of the liquid phase 601 can be obtained in real time. l .

[0091] The volume fraction V of liquid phase 601 is obtained using a fiber optic sensor. l The principle is that the volume fraction V of liquid phase 601 l The magnitude of the liquid phase 601 can affect optical parameters (reflected light intensity, refractive index, or transmittance). Changes in these optical parameters are collected via optical fiber to obtain the volume fraction V of the liquid phase 601 in real time. l .

[0092] The volume fraction V of liquid phase 601 was obtained using an ultrasonic sensor. l The principle is that the volume fraction V of liquid phase 601 l The magnitude of the sound wave can affect the sound wave parameters (propagation speed and attenuation amplitude). By collecting changes in the sound wave parameters, the volume fraction V of liquid phase 601 can be obtained in real time. l .

[0093] In some embodiments, a method for obtaining the pressure P of the gas-liquid two-phase flow located at the starting part 112a may include obtaining the pressure P using at least one of a piezoresistive sensor, a piezoelectric sensor, and a capacitive sensor.

[0094] The principle of using a piezoresistive sensor to obtain the pressure P of a gas-liquid two-phase flow is that the pressure P of the gas-liquid two-phase flow can affect the resistance of the semiconductor material. By collecting the change in resistance, the pressure P of the gas-liquid two-phase flow can be obtained in real time.

[0095] The principle of using a piezoelectric sensor to obtain the pressure P of a gas-liquid two-phase flow is that the pressure P of the gas-liquid two-phase flow affects the degree of deformation of the piezoelectric material, thereby affecting the magnitude of the current generated by the piezoelectric material. The pressure P of the gas-liquid two-phase flow can be obtained in real time by collecting the current change.

[0096] The principle of using a capacitive sensor to obtain the pressure P of a gas-liquid two-phase flow is that the pressure P of the gas-liquid two-phase flow can affect the distance between the capacitor plates, thereby affecting the capacitance value. By detecting the change in capacitance value, the pressure P of the gas-liquid two-phase flow can be obtained in real time.

[0097] In some embodiments, the initial temperature T of the gas-liquid two-phase flow located at the starting section 112a is obtained. c The method includes: obtaining the initial temperature T using at least one of a thermocouple sensor, a resistance temperature detector (RTD) sensor, and a thermistor sensor. c .

[0098] If a thermocouple sensor is used to obtain the initial temperature T cThe principle of which is to utilize the Seebeck effect, if the initial temperature T c The principle of which is to utilize the positive temperature coefficient characteristic of metal resistance, if the initial temperature T c The principle of which is to utilize the resistance-temperature characteristic of semiconductor material.

[0099] Similarly, in some embodiments, the method for obtaining the superheat temperature T Δ of the gas phase 602 located at the end portion 112b with the superheat degree T g includes: obtaining the superheat temperature T g by using at least one of a thermocouple sensor, a thermal resistance sensor, and a thermistor sensor.

[0100] In other embodiments, as shown in Figure 6 , the energy storage system can further include a drive pump 70, the drive pump 70 is arranged on the pipeline 20 connecting the condenser 40 and the throttling valve 50, and the drive pump 70 can be used to provide power for driving the flow of the refrigerant 60. Accordingly, if the mass flow rate q of the refrigerant 60 is preset or the mass flow rate q of the refrigerant 60 is adjusted, the rotational speed of the drive pump 70 can be controlled according to the set value, so that the mass flow rate of the refrigerant 60 actually flowing into the flow channel 11 of the liquid cooling plate 1 conforms to the set value. The subsequent content herein mainly takes the energy storage system not including the drive pump as an example for description.

[0101] In a second aspect, the present application provides some embodiments of the battery device, as shown in Figure 1 , Figure 3 and Figure 4 , the battery device 10 includes a liquid cooling plate 1 and a battery assembly 2, the liquid cooling plate 1 is provided with a flow channel 11, the flow channel 11 is used for circulating the refrigerant 60, and the flow channel 11 includes a main flow channel 111 and an extension flow channel 112 connected in communication, the outer structural wall of the main flow channel 111 contacts the outer structural wall of the battery assembly 2, and the outer structural wall of the extension flow channel 112 is away from the outer structural wall of the battery assembly 2, and the extension flow channel 112 is used for conducting heat from a heat source other than the battery assembly 2 to the refrigerant 60. In combination with the above description of the flow channel 11, the refrigerant 60 absorbs the heat of the battery assembly 2 in the main flow channel 111, and the refrigerant 60 changes from the liquid phase 601 to the gas-liquid two-phase flow (including the liquid phase 601 and the gas phase 602 at the same time), that is, the refrigerant 60 at the end 111a of the main flow channel 111 should be the gas-liquid two-phase flow, and the gas-liquid two-phase flow flows from the main flow channel 111 into the extension flow channel 112, and the gas-liquid two-phase flow located in the extension flow channel 112 can absorb heat from a heat source (such as a heating element) other than the battery assembly 2, so that the refrigerant 60 changes from the gas-liquid two-phase flow to the gas phase 602 with the superheat degree T ΔThe battery device 10 can also have the technical effects of the above-described embodiments of the thermal management method for some energy storage systems, which are not repeated here.

[0102] The outer structural wall of the main flow channel 111 contacts the bottom wall of the battery assembly 2, and the battery assembly 2 is located on top of or above the outer structural wall of the main flow channel 111.

[0103] In some other embodiments (not shown in the figures), the outer structural wall of the main flow channel can also contact the side wall of the battery assembly.

[0104] In some embodiments, as shown in Figure 7 , the battery device can further include a heat-generating element 4, which can be arranged on the outer structural wall of the extended flow channel 112. The heat-generating element 4 is used to generate heat, and the generated heat can be conducted to the refrigerant 60 through the extended flow channel 112, so that the refrigerant 60 is converted from a gas-liquid two-phase flow to a gas phase 602 with a superheat T Δ .

[0105] As shown in Figure 7 , the heat-generating element 4 can be arranged above the outer structural wall of the extended flow channel 112.

[0106] Due to the effect of gravity, the gas phase in the extended flow channel will be above the liquid phase. In some other embodiments, the heat-generating element can be arranged below the outer structural wall of the extended flow channel, or heat-generating elements can be arranged above and below the outer structural wall of the extended flow channel, so that some liquid phase at the lower position is close to the heat-generating element to quickly absorb the heat of the heat-generating element and vaporize.

[0107] In some other embodiments (not shown in the figures), the heat-generating element can also be arranged in the extended flow channel, so that the heat generated by the heat-generating element can be quickly conducted to the refrigerant, and the heat transfer efficiency is relatively high. The subsequent content of this paper mainly describes the heat-generating element 4 arranged on the top of the outer structural wall of the extended flow channel 112 as shown in Figure 7 . Figure 7 As shown in , the heat-generating element 4 can be a positive temperature coefficient heater.

[0108]

[0108] In other embodiments, in addition to the battery assembly 2 generating heat during operation, the battery management unit (BMU) included in the battery device also generates heat during operation. The heat generated by the BMU can be conducted to the refrigerant 60 via the extended flow channel 112. Accordingly, the battery management unit (not shown in the figure) can be disposed on the outer structural wall of the extended flow channel 112. Therefore, the battery device can have the advantage of heat recovery, and the operating energy consumption of the heat-generating components can be relatively low.

[0109] The outer wall of the battery management unit can be directly mounted on the outer structural wall of the extended flow channel 112. Furthermore, thermally conductive adhesive can be applied between the outer wall of the battery management unit and the outer structural wall of the extended flow channel 112 to improve heat transfer efficiency.

[0110] In addition, a heat-conducting component (e.g., a heat pipe) can be provided between the heat source (e.g., a power device) inside the battery management unit and the outer structural wall of the extended flow channel 112. The heat-conducting component can conduct the heat from the heat source inside the battery management unit to the outer structural wall of the extended flow channel 112 to improve heat transfer efficiency.

[0111] In some embodiments, please refer to Figure 7 As shown, the extended flow channel 112 also includes a starting part 112a and a ending part 112b, with the starting part 112a located near the end 111a of the main flow channel 111 relative to the ending part 112b. During the flow of the refrigerant 60 from the main flow channel 111 to the extended flow channel 112, the refrigerant 60 first passes through the starting part 112a and then through the ending part 112b.

[0112] In some embodiments, please refer to Figure 7 As shown, the battery device may include an ultrasonic sensor 5. The ultrasonic sensor 5 is not located within the extended flow channel 112, but is disposed on the outer structural wall of the starting portion 112a. The ultrasonic sensor 5 is used to detect the volume fraction V of the liquid phase 601 of the refrigerant 60 located in the starting portion 112a. l The relevant principles and effects have been described above and will not be repeated here.

[0113] In some other embodiments, the ultrasonic sensor 5 may be independent of the battery device, meaning that both the ultrasonic sensor 5 and the battery device are components of the energy storage system.

[0114] In some embodiments, please refer to Figure 7As shown, the battery device can include a pressure sensor 6, which is located in the elongated flow channel 112, is arranged in the starting portion 112a, and is configured to detect the pressure P of the refrigerant 60 in the starting portion 112a. The related principles and effects have been described above and will not be repeated here.

[0115] In some embodiments, referring to Figure 7 As shown, the battery device can include a first temperature sensor 7, which is located in the elongated flow channel 112, is arranged in the starting portion 112a, and is configured to detect the initial temperature T of the refrigerant 60 in the starting portion 112a. c The related principles and effects have been described above and will not be repeated here.

[0116] In some embodiments, referring to Figure 7 As shown, the battery device can include a second temperature sensor 8, which is located in the elongated flow channel 112, is arranged in the ending portion 112b, and is configured to detect the overheat temperature T of the refrigerant 60 in the ending portion 112b. g The related principles and effects have been described above and will not be repeated here.

[0117] In some embodiments, referring to Figure 8 As shown, the flow passage cross-sectional area S2 of the elongated flow channel 112 is greater than the flow passage cross-sectional area S1 of the main flow channel 111. In combination with the arrangement of the elongated flow channel 112 closer to the suction end of the compressor 30 than the main flow channel 111, the pressure in the space of the elongated flow channel 112 is lower than the pressure in the space of the main flow channel 111. In this arrangement, after the gas-liquid two-phase flow flows from the main flow channel 111 into the elongated flow channel 112, the pressure of the gas-liquid two-phase flow decreases, the boiling point of the liquid phase 601 in the gas-liquid two-phase flow decreases, and the liquid phase 601 can be converted into the gas phase 602 under the condition of absorbing relatively less heat. Therefore, the heat provided by the heat generating component is relatively less, and the working energy consumption of the heat generating component is relatively lower. The ratio of the flow passage cross-sectional area S2 to the flow passage cross-sectional area S1 can be in the range of 1.1-2, and the ratio of the flow passage cross-sectional area S2 to the flow passage cross-sectional area S1 can be 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or 2.

[0118] In some embodiments, as known from the above, the battery assembly 2 can be located above the liquid cooling plate 1, and the heat of the battery assembly 2 is conducted from top to bottom to the refrigerant 60. When the refrigerant 60 flows in the main flow channel 111, the refrigerant 60 is converted from the liquid phase 601 to the gas-liquid two-phase flow. Under the action of gravity, the gas phase 602 of the gas-liquid two-phase flow is located above the liquid phase 601, and the gas phase 602 is closer to the battery assembly 2 than the liquid phase 601. Referring to Figure 9As shown, the liquid cooling plate 1 may further include a flow guide 12, which may be disposed within the main flow channel 111. The guiding portion of the flow guide 12, which has a guiding function, is inclined relative to the extension direction (e.g., the front-to-back direction) of the main flow channel 111. The portion of the guiding portion near the extended flow channel 112 is higher than the portion of the guiding portion away from the extended flow channel 112. In this configuration, when the liquid phase 601 included in the gas-liquid two-phase flow flows within the main flow channel 111 and contacts the guiding portion of the flow guide 12, under the guiding action of the guiding portion of the flow guide 12, some of the liquid phase 601 will flow upward (e.g., flow in direction A). The upwardly flowing liquid phase 601 may approach the upper battery assembly 2, or in other words, the upwardly flowing liquid phase 601 may approach the top of the inner surface of the main flow channel 111. Since the specific heat capacity of liquid phase 601 is greater than that of gas phase 602, meaning that the heat absorption capacity of liquid phase 601 is greater than that of gas phase 602, the flow guide 12 can enable some liquid phase 601 to quickly absorb the heat of battery module 2, so that the heat dissipation efficiency of battery module 2 is relatively large.

[0119] The guide element 12 can also have a turbulence function. After the guide element 12 guides some liquid phase 601 to flow upward and absorb more heat, the liquid phase 601 detaches from the guide element 12 and flows downward due to gravity. The downward flowing liquid phase 601 mixes with other liquid phase 601 that originally flowed at a lower position, thereby allowing heat to be quickly conducted to the liquid phase 601 that flowed at a lower position.

[0120] Additionally, the flow guide 12 can be as follows: Figure 9 The flow guide 12 can be a plate-like structure, a sheet-like structure, or a tubular structure. When the flow guide 12 is a plate-like or sheet-like structure, its upper inclined surface can serve as a guide portion with a guiding function. When the flow guide 12 is an inclined tubular structure, its inner wall can serve as a guide portion with a guiding function. In some other embodiments, the flow guide 12 can also be as shown... Figure 10 The inclined surface of the flow guide 12, as shown in the sloping structure, can serve as a guide with a guiding function.

[0121] Furthermore, the inner wall of the guide component 12 and the main channel 111 can be integrally formed, bonded, snapped, or magnetically connected.

[0122] In some embodiments, please refer to Figure 9 As shown, at least two flow guides 12 can be provided within the main flow channel 111, and the at least two flow guides 12 are spaced apart along the extension direction of the main flow channel 111. Therefore, under the guidance of multiple flow guides 12, a relatively large amount of liquid phase 601 can approach the upper battery assembly 2, or in other words, a relatively large amount of liquid phase 601 can approach the top of the inner surface of the main flow channel 111, so that the heat dissipation efficiency of the battery assembly 2 is relatively large.

[0123] In some embodiments, as known from the above, the less liquid phase 601 there is in the main flow channel 111 at a position closer to the elongated flow channel 112, i.e. the lower the liquid level of the liquid phase 601 in the main flow channel 111 at a position closer to the elongated flow channel 112. Please refer to Figure 9 illustrated, the closer to the bottom of the flow guide 12 of the elongated flow channel 112, the closer to the bottom of the main flow channel 111, thus any flow guide 12 in the elongated flow channel 112 can reliably guide the liquid phase 601 to be close to the battery assembly 2 above, or in other words, any flow guide 12 in the elongated flow channel 112 can reliably guide the liquid phase 601 to be close to the top of the inner surface of the main flow channel 111, so that the battery assembly 2 has a relatively large heat dissipation efficiency.

[0124] In some embodiments, please refer to Figure 9 illustrated, the closer to the top of the flow guide 12 of the elongated flow channel 112, the closer to the top of the main flow channel 111, thus the flow guide 12 of the elongated flow channel 112 can more reliably guide the liquid phase 601 to be close to the battery assembly 2 above and the top of the inner surface of the main flow channel 111, so that the battery assembly 2 has a relatively large heat dissipation efficiency.

[0125] In some embodiments, please refer to Figure 9 illustrated, the flow guide 12 can be arranged at the end 111a of the main flow channel 111, so that some liquid phase 601 at the end 111a can flow upward along the direction A, thereby making some battery monomers 21 in the battery assembly 2 close to the end 111a of the main flow channel 111 have a relatively large heat dissipation efficiency.

[0126] In other embodiments (not shown in the drawings), when the heat generating member is arranged above the elongated flow channel, a flow guide can also be arranged in the elongated flow channel, which can guide some liquid phase at a low position to be close to the heat generating member upward, so as to increase the rate of gasification of the liquid phase, or the flow guide can guide some gas phase at a low position to be close to the heat generating member upward, so that the gas phase quickly rises from the saturation temperature T s to the overheating temperature T g The structure of the flow guide in the elongated flow channel can refer to the structure of the flow guide in the main flow channel, the shape of the flow guide in the elongated flow channel can refer to the shape of the flow guide in the main flow channel, and the number of the flow guide in the elongated flow channel can refer to the number of the flow guide in the main flow channel, which will not be described here.

[0127] In some embodiments, please refer to Figure 11As shown, the main flow channel 111 can be provided with a spiral guide portion 111b, which can guide some liquid phase 601 at low position to move upward spirally, so as to make some liquid phase 601 at low position close to the battery assembly 2 above, or in other words, to make some liquid phase 601 at low position close to the top of the inner surface of the main flow channel 111, so as to make the heat dissipation efficiency of the battery assembly 2 relatively large. After some liquid phase 601 at low position in the main flow channel 111 absorbs heat, the liquid phase 601 will also move downward spirally along the spiral guide portion 111b, so as to mix the liquid phase 601 at low position with the liquid phase 601 carrying more heat, so as to make the heat quickly conduct to the liquid phase 601 at low position.

[0128] In some embodiments, the spiral guide portion 111b can be provided on the inner surface of the main flow channel 111, or the spiral guide portion 111b can be provided mainly on the inner surface of the end portion 111a of the main flow channel 111.

[0129] In other embodiments (not shown in the figure), when the heat generating member is provided above the elongated flow channel, the elongated flow channel can also be provided with a spiral guide portion, which can guide some liquid phase at low position to move upward to close to the heat generating member, so as to increase the vaporization rate of the liquid phase, or the spiral guide portion can guide some gas phase at low position to move upward to close to the heat generating member, so as to make the gas phase quickly rise from the saturation temperature T s to the superheat temperature T g .

[0130] In other embodiments, please refer to Figure 12 As shown, the bottom of the end portion 112b of the elongated flow channel 112 can be provided with a liquid storage groove 112c, which is used to accumulate some residual liquid phase 601 at low position and not vaporized into gas phase 602 in time, so as to make the residual liquid phase 601 can temporarily stay in the liquid storage groove 112c and continue to absorb heat to vaporize into gas phase 602, so that the battery device can have the advantage of reliably preventing the problem of liquid strike of the compressor 30.

[0131] In some embodiments, the number of the liquid storage groove 112c can be one, two, three or other numbers.

[0132] In some embodiments, please refer to Figure 13As shown, when the heat-generating element 4 is on the outer structural wall of the extended flow channel 112, the battery device may further include a heat shield 9. The heat shield 9 covers a portion of the outer structural wall of the extended flow channel 112 and covers the heat-generating element 4. In other words, the heat-generating element 4 is located within the accommodating space 9a formed by the heat shield 9 and the outer structural wall of the extended flow channel 112. In this configuration, some of the overflow heat generated by the heat-generating element 4 (heat not absorbed by the outer structural wall of the extended flow channel 112) can be blocked by the heat shield 9 within the accommodating space 9a. The overflow heat located within the accommodating space 9a can be conducted to the refrigerant 60 via the outer structural wall of the extended flow channel 112. Therefore, the heat shield 9 has energy-saving advantages. Furthermore, the heat shield 9 can reduce the likelihood of the battery assembly 2 being affected by overflow heat, allowing the battery assembly 2 to be reliably cooled by the refrigerant 60.

[0133] Please refer to Figure 14 As shown, the heating element 4 can be disposed above the outer structural wall of the extended flow channel 112, and correspondingly, the heat insulation cover 9 can also be disposed above the outer structural wall of the extended flow channel 112. In some other embodiments (not shown in the figure), the heating element can be disposed below the outer structural wall of the extended flow channel, and correspondingly, the heat insulation cover can also be disposed below the outer structural wall of the extended flow channel.

[0134] In some other embodiments, please refer to Figure 1 As shown, the outer structural wall of the extended flow channel 112 has an upwardly protruding portion 112d. With this configuration, the heat absorption area at the top of the outer structural wall of the extended flow channel 112 is relatively large, and the rate at which overflowing heat is conducted to the refrigerant 60 through the outer structural wall of the extended flow channel 112 is relatively high. The number of protrusions 112d can be one, two, or more. Furthermore, the shape of the protrusions 112d can be sheet-like, block-like, or other shapes.

[0135] In some embodiments, please refer to Figure 15- Figure 16 As shown, the battery device 10 may include a top cover 3, which covers the battery assembly 2. Correspondingly, the top cover 3 also covers the top of the outer structural wall of the main flow channel 111. The top cover 3 may also cover the top of the outer structural wall of the extended flow channel 112.

[0136] In some other embodiments (not shown in the figures), the top cover may be placed over a portion of the top of the outer structural wall of the extended flow channel.

[0137] In some embodiments, please refer to Figure 15As shown, the upper cover 3 can not be provided on the top of the outer structural wall of the extended flow channel 112. In this arrangement, when the heat generating member is provided on the outer structural wall of the extended flow channel 112, the heat generated by the heat generating member can be blocked outside the upper cover 3 by the upper cover 3, so that the battery assembly 2 is not easily affected by the heat generated by the heat generating member, thereby enabling the battery assembly 2 to be reliably cooled by the refrigerant 60. For reference, please refer to Figure 16 As shown, the extension direction of the main flow channel 111 and the extension direction of the extended flow channel 112 can be parallel. For reference, please refer to Figure 16 As shown, the extension direction of the main flow channel 111 and the extension direction of the extended flow channel 112 can be intersected. For example, in Figure 17 , at least part of the structure of the extended flow channel 112 can extend upward, that is, the height of at least part of the structure of the extended flow channel 112 is greater than the height of the main flow channel 111, so that the compactness of the battery device 10 is relatively large, thereby the occupied space of the battery device 10 is relatively small, further, the liquid phase 601 located in the extended flow channel 112 is accumulated at the bottom of the extended flow channel 112 under the action of gravity, the liquid phase 601 can fully absorb heat and vaporize into the gas phase 602 at the bottom of the extended flow channel 112, and the liquid phase 601 is difficult to directly enter the compressor 30 after overcoming the gravity and moving upward in the extended flow channel 112, thereby reliably preventing the liquid strike problem of the compressor 30.

[0138] In other embodiments (not shown in the figure), at least part of the structure of the extended flow channel can extend along a direction intersecting the up-down direction and the front-rear direction, and at least part of the structure of the extended flow channel is higher than the main flow channel. The subsequent content herein mainly describes the liquid cooling plate 1 with the example of "the height of the main flow channel 111 and the height of the extended flow channel 112 are the same".

[0139] In some embodiments, as shown in Figure 17 , the distribution of the flow channel 11 of the liquid cooling plate 1 is as follows when viewed in the up-down direction. Figure 18 In the figure, the black solid triangular arrow represents the flow direction of the refrigerant, and the main flow channel 111 is in a U-shaped or C-shaped distribution.

[0140] In some embodiments, as shown in Figure 18 , the distribution of the flow channel 11 of the liquid cooling plate 1 is as follows when viewed in the up-down direction. Figure 2 In the figure, the black solid triangular arrow represents the flow direction of the refrigerant. A plurality of partitioning portions 13 are provided in the main flow channel 111 and the extended flow channel 112, so that the space in the main flow channel 111 is divided into a plurality of sub-flow channel spaces by the partitioning portions 13, and the space in the extended flow channel 112 is divided into a plurality of sub-flow channel spaces by the partitioning portions 13.

[0141] In a third aspect, the present application provides some embodiments of an energy storage system, which can include the embodiments and technical effects of the above-described battery device 10, which will not be repeated here. The energy storage system can also include Figure 6 the structure shown in FIG. 1 or ​ the structure shown in FIG. 2.

[0142] In some embodiments, the energy storage system can also perform the embodiments of the above-described thermal management method of the energy storage system, and thus the energy storage system can also have the technical effects brought by the embodiments of the above-described thermal management method of the energy storage system, which will not be repeated here.

[0143] In some embodiments, the energy storage system can include a control component, which can collect the volume fraction V l , the pressure P, the initial temperature T c , and the overheating temperature T g through various sensors described above. The control component can calculate the mass flow rate q and the heat generation power P PTC of the heat generation component according to the collected data according to a set program. The control component can convert the calculated mass flow rate q into a working frequency signal for controlling the compressor or a rotating speed signal for controlling the driving pump, so that the actual mass flow rate of the refrigerant flowing into the flow channel 11 meets (with a certain error allowed) the calculated mass flow rate q. The control component can convert the calculated heat generation power P PTC into a current signal for controlling the heat generation component, so that the actual heat generation power of the heat generation component meets (with a certain error allowed) the calculated heat generation power P PTC .

[0144] In some embodiments, according to the above, the energy storage system further comprises a compressor 30 outside the battery device. When the compressor 30 is working, the compressor 30 also generates heat, and the heat generated by the compressor 30 can also be recovered. Accordingly, the energy storage system can comprise a first circulation pipeline (not shown in the figure) and a first liquid pump (not shown in the figure). The first circulation pipeline has a first heat absorption part and a first heat release part. The first heat absorption part is connected with the compressor 30, and the first heat release part is connected with the outer structural wall of the extension flow channel 112. The first circulation pipeline is filled with cooling liquid, and the first liquid pump can drive the cooling liquid to circulate in the first circulation pipeline. When the cooling liquid flows to the first heat absorption part, the cooling liquid can absorb the heat generated by the compressor 30 through the first heat absorption part. The cooling liquid after absorbing heat flows to the first heat release part, and the cooling liquid releases heat to the extension flow channel 112 through the first heat release part. The released heat can be conducted to the refrigerant 60 in the extension flow channel 112, and the cooling liquid after releasing heat flows back to the first heat absorption part to continue to absorb the heat generated by the compressor 30, thereby realizing the above heat circulation process. In this arrangement, the heat generated by the compressor 30 can be used to change the refrigerant 60 in the extension flow channel 112 from a gas-liquid two-phase flow to a gas phase 602 with superheat T Δ , that is, it has the advantage of energy recovery. Accordingly, the energy consumption of the heating element using the electric heating principle can be relatively low, that is, it has the advantage of energy saving.

[0145] In other embodiments, according to the above, the energy storage system further comprises a condenser 40 outside the battery device. When the condenser 40 is working, the condenser 40 also releases heat to the outside, and the heat released by the condenser 40 can also be recovered. Accordingly, the energy storage system can comprise a second circulation pipeline (not shown in the figure) and a second liquid pump (not shown in the figure). The second circulation pipeline has a second heat absorption part and a second heat release part. The second heat absorption part is connected with the condenser 40, and the second heat release part is connected with the outer structural wall of the extension flow channel 112. The second circulation pipeline is filled with cooling liquid, and the second liquid pump can drive the cooling liquid to circulate in the second circulation pipeline. When the cooling liquid flows to the second heat absorption part, the cooling liquid can absorb the heat released by the condenser 40 through the second heat absorption part. The cooling liquid after absorbing heat flows to the second heat release part, and the cooling liquid releases heat to the extension flow channel 112 through the second heat release part. The released heat can be conducted to the refrigerant 60 in the extension flow channel 112, and the cooling liquid after releasing heat flows back to the second heat absorption part to continue to absorb the heat released by the condenser 40, thereby realizing the above heat circulation process. In this arrangement, the heat released by the condenser 40 can be used to change the refrigerant 60 in the extension flow channel 112 from a gas-liquid two-phase flow to a gas phase 602 with superheat T Δ , that is, it has the advantage of energy recovery. Accordingly, the energy consumption of the heating element using the electric heating principle can be relatively low, that is, it has the advantage of energy saving.

[0146] In a fourth aspect, the present application provides some embodiments of an electrical device, which can also be referred to as an electrical system. The electrical device can include the embodiments and technical effects described above with respect to the battery device, which will not be repeated here. The electrical device can be a vehicle, a ship, a spacecraft, a household appliance, or any other device that utilizes electrical energy.

[0147] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Various modifications and changes can be made by those skilled in the art based on the spirit and principles of the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A thermal management method for an energy storage system, characterized by, The energy storage system includes a battery device, which includes a liquid cooling plate, a battery assembly, and an electric heating element. The liquid cooling plate has a flow channel for circulating refrigerant. The flow channel includes a main flow channel and an extended flow channel that are connected to each other. The outer structural wall of the main flow channel is in contact with the battery assembly, and the outer structural wall of the extended flow channel is away from the battery assembly. The extended flow channel includes a starting part and a ending part, with the starting part located closer to the end of the main flow channel relative to the ending part. The thermal management method of the energy storage system includes: The refrigerant located in the main flow channel absorbs the heat of the battery assembly, thereby changing the refrigerant from a liquid phase to a gas-liquid two-phase flow. The refrigerant flows from the main flow channel into the extended flow channel; The refrigerant located in the extended flow channel absorbs heat from the electric heating element, thereby changing the refrigerant from a gas-liquid two-phase flow to a superheated gas phase. Before driving the refrigerant flow, a mass flow rate q of the refrigerant is preset to satisfy q = k(P cf + M · C c · t) / H l , k is a correction coefficient, P cf is a cell heat release power of the battery assembly, M is a mass of the battery assembly, C c is a specific heat capacity of the battery assembly, t is a cooling rate, and H l is a latent heat of vaporization of the liquid phase. in the process of driving the flow of the refrigerant, the heat generation power P of the electric heating member is adjusted according to the mass flow rate q PTC , P PTC =P PTC1 +P PTC2 , P PTC1 =H l ·q·ρ l ·V l / (ρ l ·V l +P(1-V l ) / (T c +273.15)R), P PTC2 =(T g -T s ) C g ·q, P PTC1 is a first heat generation power, P PTC2 is a second heat generation power, ρ l is the density of the liquid phase, V l is the volume fraction of the liquid phase included in the gas-liquid two-phase flow at the start portion, P is the pressure of the gas-liquid two-phase flow at the start portion, T c is the initial temperature of the gas-liquid two-phase flow at the start portion, R is a gas constant, T g is the superheat temperature of the gas phase at the end portion, T s is the saturation temperature, and C g is the specific heat capacity of the gas phase.

2. The thermal management method of an energy storage system of claim 1, wherein, The thermal management method for the energy storage system also includes: During the process of driving the refrigerant flow, the heating power P is adjusted. PTC Then, based on the stated heating power P PTC Adjust the mass flow rate q to satisfy q=(P cf +P PTC ) / (H l +(T g -T s C g ).

3. The thermal management method of an energy storage system of claim 1, wherein, acquiring a volume fraction V of a liquid phase included in the gas-liquid two-phase flow at the start portion l The method includes: acquiring the volume fraction V using at least one of a capacitive sensor, an optical fiber sensor, and an ultrasonic sensor l .

4. The thermal management method of an energy storage system of claim 1, wherein, The method for obtaining the pressure P of the gas-liquid two-phase flow located at the starting point includes: The pressure P is obtained using at least one of a piezoresistive sensor, a piezoelectric sensor, and a capacitive sensor.

5. The thermal management method of an energy storage system of claim 1, wherein, acquiring an initial temperature T of the gas-liquid two-phase flow located at the start portion c The method includes acquiring the initial temperature T using at least one of a thermocouple sensor, a thermal resistance sensor, and a thermistor sensor c ; and / or, acquiring a superheat temperature T of the gas phase having a superheat degree located at the end portion g The method includes acquiring the superheat temperature T of the gas phase having a superheat degree located at the end portion using at least one of a thermocouple sensor, a thermal resistance sensor, and a thermistor sensor g .

6. A battery device characterized by comprising: The battery device is used to perform the thermal management method of the energy storage system according to any one of claims 1 to 5. The battery device includes a liquid cooling plate, a battery assembly, and an electric heating element. The liquid cooling plate has a flow channel for circulating refrigerant. The flow channel includes a main flow channel and an extended flow channel that are connected to each other. The outer structural wall of the main flow channel is in contact with the outer structural wall of the battery assembly. The outer structural wall of the extended flow channel is away from the outer structural wall of the battery assembly. The electric heating element is disposed on the outer structural wall of the extended flow channel or in the extended flow channel. The extended flow channel is used to conduct the heat of the electric heating element to the refrigerant.

7. The battery device of claim 6, wherein The extended flow channel further includes a starting portion and a ending portion, the starting portion being located near the end of the main flow channel relative to the ending portion, and the battery device further satisfies at least one of the following settings: Setting (a): the battery device includes an ultrasonic sensor disposed to an outer structure wall of the starting portion, the ultrasonic sensor being used to detect a volume fraction V of the liquid phase of the refrigerant located at the starting portion l ; Configuration (b): The battery device further includes a pressure sensor disposed in the starting part, the pressure sensor being used to detect the pressure P of the refrigerant located in the starting part; Setting (c): the battery device further includes a first temperature sensor, which is disposed in the starting portion, and which is used to detect the initial temperature T of the refrigerant located in the starting portion c ; Setting (d): the battery device further includes a second temperature sensor, which is arranged in the tail portion, and which is used to detect the superheat temperature T of the refrigerant located in the tail portion g .

8. The battery device of claim 6, wherein, The cross-sectional area of ​​the extended flow channel is larger than the cross-sectional area of ​​the main flow channel.

9. The battery device of claim 6, wherein, The outer structural wall of the main channel contacts the bottom wall of the battery assembly.

10. The battery device of claim 6, wherein, The battery device includes a top cover that covers the battery assembly; The top cover may be disposed on at least a portion of the top of the outer structural wall of the extended flow channel, or the top cover may not be disposed on the top of the outer structural wall of the extended flow channel.

11. The battery device of claim 6, wherein, The extension direction of the main flow channel is parallel or intersects with the extension direction of the extended flow channel.

12. An energy storage system characterized by, The energy storage system is used to perform the thermal management method of the energy storage system according to any one of claims 1 to 5, or the energy storage system includes the battery device according to any one of claims 6 to 11.

13. An electrical device, characterized by The electrical equipment includes the battery device according to any one of claims 6 to 11.

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