Liquid cooling pipeline and phase change material compounded novel energy storage system and method

Abstract

The invention relates to a liquid cooling pipeline and phase change material compounded novel energy storage system and method, which are mainly applied to the field of battery energy storage in an extremely cold environment. The system comprises a liquid cooling unit, a liquid cooling pipeline system, a battery cluster, a phase change module, a multi-stage bypass system, a valve system and a circulating pump. Through cooperative work of the liquid cooling unit and the phase change module, the system can recover the heat of the cooling liquid after the battery is heated and store the heat in the phase change module, and the heat stored in the phase change module is preferentially used for heating when the temperature of the battery is relatively low, so that the energy consumption of the liquid cooling unit is reduced, and the energy efficiency of the system is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of battery energy storage, and particularly to a system combining a liquid cooling pipeline and a phase change module of an energy storage container, with the main application scenario being extremely cold environments. Background Art

[0002] China's energy storage demand in extremely cold environments is facing unprecedented strategic opportunities and technical challenges, especially in vast areas with an average annual temperature below -10°C and extreme low temperatures breaking through -40°C. The winter power load in these regions surges by 50% - 80% compared to summer. For example, the single-day power gap in Inner Mongolia during the heating season in 2023 reached 800 megawatts. At the same time, the spatial mismatch between wind and solar resources and load centers exacerbates the supply-demand contradiction - the effective power generation duration of photovoltaic in Altay, Xinjiang in winter is less than 4 hours, and the unavailability rate of wind power in Daxing'anling, Heilongjiang during cold snaps is as high as 65%, forcing the energy storage system to bear a longer peak shaving cycle.

[0003] In extremely cold environments, the following problems exist in liquid-cooled energy storage containers: 1. The performance decline of the coolant leads to a reduction in thermal management efficiency. The viscosity rises sharply at low temperatures, which may cause the flow resistance to double or even phase change blockage, while adding antifreeze will weaken the specific heat capacity; 2. The battery preheating requirement forces the system to additionally configure a high-power electric heating module, significantly compressing the effective energy storage capacity; 3. The operation and maintenance are complex and difficult. Equipment maintenance in low-temperature environments is difficult and the safety risk is high.

[0004] In the prior art, Patent CN119253132A proposed a centralized high-efficiency liquid-cooled energy storage container, Patent CN219832795U relates to the coolant flow mode of a liquid-cooled energy storage container, Patent CN202211082028.5 relates to a temperature control system for a container energy storage device based on phase change cooling, and Patent CN119361907A relates to a constant-temperature air-cooled system for an energy storage container. However, these patents have deficiencies in how to recover and reuse the heat inside the liquid-cooled energy storage container in extremely cold environments. Summary of the Invention

[0005] In order to solve the defects existing in the prior art, the present invention discloses a [system name not provided in the original], and its technical solution is as follows: A novel energy storage system combining a liquid cooling pipeline and a phase change material, characterized by comprising: A liquid cooling unit for cooling or heating the coolant; The liquid cooling pipeline system includes multi-stage pipelines, a coolant output pipeline, and a coolant converging pipeline, which are used for the circulating flow of coolant in the system. The multi-stage pipelines include at least one stage of input pipelines and one stage of output pipelines, which are used to distribute coolant to the battery modules and recover the coolant. The specific connection method between the liquid cooling pipeline system and the multi-stage bypass system can be adjusted according to actual needs; The battery cluster, which is composed of multiple battery modules, is installed in a battery rack. The battery modules are connected to the liquid cooling pipeline system through the coolant inlets and outlets of the battery plug-in boxes; The phase change module is used to store and release the heat in the coolant, and includes a heat preservation shell, heat transfer tubes, heat transfer fins, a coolant distributor, and a phase change material encapsulation body. The phase change material encapsulation body is filled with a phase change material such as paraffin or fatty acid, and 5%-20% of aluminum powder or graphite powder is incorporated to improve the thermal conductivity; The multi-stage bypass system includes at least one bypass, which is used to control the path of the coolant flowing through the phase change module; The valve system includes at least one four-way valve and multiple three-way valves, which are used to adjust the flow direction of the coolant; The circulation pump is used to push the coolant to circulate in the system; Among them, the liquid cooling unit, the liquid cooling pipeline system, the phase change module, and the multi-stage bypass system work together. By recovering the heat of the coolant heated by the battery and storing it in the phase change module, the heat stored in the phase change module is preferentially used for heating when the battery temperature is low, reducing the energy consumption of the liquid cooling unit and improving the energy efficiency of the system.

[0006] The present invention also discloses a novel energy storage method combining a liquid cooling pipeline and a phase change material, which is characterized by including the following steps: When the battery temperature Tmax≥N1, the system enters the refrigeration mode, and the coolant flows through the phase change module to store heat; When the battery temperature Tmin≤N2, the system enters the heating mode, and the heat stored in the phase change module is preferentially used to heat the battery; When the battery temperature Tmax≥N3 and Tmin≤N4, the system enters the self-circulation mode, and the coolant circulates between the battery plug-in box and the liquid cooling unit; When the battery temperature Tmax≥N5 and Tmin≤N6, the system enters the standby mode to reduce energy consumption; Among them, N1, N2, N3, N4, N5, and N6 are preset temperature values, and N1>N3>N5, N2<N4<N6. The temperature values N1-N6 can be adjusted according to the battery type and environmental conditions.

[0007] The present invention also discloses the application of a new energy storage system combined with a liquid cooling pipeline and a phase change material in an extremely cold environment. It is characterized in that the system stores and releases heat through a phase change module, reduces the energy consumption of the liquid cooling unit, and improves the adaptability and energy efficiency of the system in an extremely cold environment. Specifically: In the scenario without external energy supply, the heat stored in the phase change module can be used as an emergency heat source to ensure that the battery maintains the basic working temperature in an extremely low temperature environment; The working load of the liquid cooling unit is reduced through a thermal energy circulation mechanism, and the service life of the core components such as the battery pack in the battery compartment, the compressor, condenser, and electric heater of the liquid cooling unit is prolonged. Beneficial effects

[0008] The waste heat of the battery is recovered through the phase change module to form a closed-loop thermal energy cycle, reducing the dependence on external energy and improving energy efficiency.

[0009] In an extremely cold environment, the phase change module can be used as an emergency heat source to ensure that the battery maintains the basic working temperature.

[0010] The working load of the liquid cooling unit is reduced, the service life of the core components is prolonged, and the life cycle cost is reduced.

[0011] The buffering capacity of the system to cope with abnormal conditions such as sudden power outages and equipment failures is enhanced, and the reliability of the system is improved. Brief description of the drawings

[0012] Figure 1 It is the overall system diagram; Figure 2 It is the overall system diagram from another perspective; Figure 3 It is the front view of the system; Figure 4 It is the right view of the system; Figure 5 It is the top view of the system; Figure 6 It is the composition diagram of the phase change module; Figure 7 It is the front view of the system with the battery cluster; Figure 8 It is the top view of the system with the battery cluster; Figure 9 It is the system control flow chart; Wherein: 101, liquid cooling unit; 102, heat dissipation port; 201, primary pipeline (input); 202, secondary pipeline (input); 203, tertiary pipeline (input); 204, tertiary pipeline (output); 205, secondary pipeline (output); 206, primary pipeline (output); 300, phase change module; 301, thermal insulation housing; 302, heat transfer pipe; 303, heat transfer fin; 304, coolant distributor; 305, phase change material encapsulation body; 401, bypass one; 402, bypass two; 403, bypass three; 501, coolant convergence pipeline; 502, coolant output pipeline; 503, pipeline; 601, battery cluster; 602, battery cassette; 603, battery rack; 604, coolant inlet of battery cassette; 605, coolant outlet of battery cassette; one four-way valve V1, three three-way valves V2, V3, V4; M, circulation pump. Detailed implementation manner

[0013] As Figures 1-5 shown, the novel energy storage system combining a liquid cooling pipeline and a phase change material includes the following components: Liquid cooling unit 101: Used to cool or heat the coolant, with components such as a compressor, condenser, electric heater, and water pump integrated inside, and can automatically switch the working mode according to the battery temperature.

[0014] Liquid cooling pipeline system: Includes primary pipeline 201, secondary pipeline 202, tertiary pipeline 203, tertiary pipeline 204, secondary pipeline 205, primary pipeline 206, coolant output pipeline 502, and coolant convergence pipeline 501, used for the circulating flow of the coolant in the system.

[0015] Battery cluster 601: Composed of multiple battery modules, installed in battery rack 603, and the battery modules are connected to the liquid cooling pipeline system through the coolant inlet 604 and coolant outlet 605 of battery cassette 602.

[0016] Phase change module 300: Used to store and release the heat in the coolant, including thermal insulation housing 301, heat transfer pipe 302, heat transfer fin 303, coolant distributor 304, and phase change material encapsulation body 305.

[0017] Bypass system: Includes bypass one 401, bypass two 402, and bypass three 403, used to control the path of the coolant flowing through the phase change module.

[0018] Valve system: Includes one four-way valve V1 and three three-way valves V2, V3, V4, used to adjust the flow direction of the coolant.

[0019] Circulation pump M: Used to push the coolant to circulate in the system.

[0020] As Figure 6As shown, the phase change module 300 consists of the following components: Thermal insulation housing 301: It adopts a double-layer galvanized steel plate sandwich structure, with rock wool or glass wool filled inside as the heat insulation layer, and is installed by bolt connection. Its main function is to reduce the influence of the external environment on the internal temperature of the module through physical isolation.

[0021] Heat transfer pipe 302: It is made of metal material pipes with good thermal conductivity such as copper pipes or aluminum pipes, and realizes the rapid transfer of heat by utilizing the high thermal conductivity of the metal pipes.

[0022] Heat transfer fins 303: They are installed on the outer wall surface of the heat transfer pipe 302, are aluminum corrugated fins, and are tightly attached to the heat transfer pipe by processes such as expansion joint after being formed by mechanical stamping. They improve the air convection heat transfer efficiency by increasing the heat dissipation area.

[0023] Coolant distributor 304: It adopts a cast aluminum housing structure, and an isobaric shunt chamber can be set inside to evenly distribute the coolant to each heat transfer pipe.

[0024] Phase change material encapsulation 305: It uses a 1mm thick aluminum sealed tank as the container, and the inside is filled with conventional phase change materials such as paraffin or fatty acids. To improve the thermal conductivity, 10%-15% of aluminum powder or graphite powder is incorporated into the phase change material, and the heat absorption and release are realized by utilizing the solid-liquid phase change characteristics of the phase change material in the range of 30-40°C.

[0025] The pipeline connection relationship of the system is described below in conjunction with the attached drawings; for the lower half of the system, the lower end of the liquid cooling unit 101 is connected to the coolant output pipeline 502; the coolant output pipeline 502 is connected to the primary pipeline (input) 201; the primary pipeline (input) 201 is connected to the bypass two 402 through the three-way valve V5; the primary pipeline (input) 201 is connected to the secondary pipeline (input) 202; the secondary pipeline (input) 202 is connected to the tertiary pipeline (input) 203; the tertiary pipeline (input) 203 is connected to the coolant inlet 604 of the battery cassette. The bypass one 401 flows through the phase change module 300, and the bypass one 401 is connected to the bypass three 403 through the three-way valve V4. For the upper half of the system, the coolant convergence pipeline 501 is connected to the bypass three 403 through the three-way valve V2; the coolant convergence pipeline 501 is connected to the primary pipeline (output) 206 through the four-way valve V1; the primary pipeline (output) 206 is connected to the secondary pipeline (output) 205; the secondary pipeline (output) 205 is connected to the tertiary pipeline (output) 204; the tertiary pipeline (output) 204 is connected to the coolant outlet 605 of the battery cassette.

[0026] It should be noted that the pipeline 503 refers to the pipeline section from the four-way valve V1 to the three-way valve V2; the bypass one 401 refers to the pipeline section from the four-way valve V1 to the three-way valve V3; the bypass three 402 refers to the pipeline section from the three-way valve V3 to the three-way valve V2; the bypass two 402 refers to the bifurcated pipeline section from the three-way valve V3 to the three-way valves 4 and 5.

[0027] It should be noted that the battery thermal management system of the liquid-cooled energy storage container mainly adopts two cooling technical paths: one is the indirect cold plate liquid cooling technology, where the coolant (usually ethylene glycol aqueous solution or silicon-based heat-conducting oil) circulates in a closed flow channel and is closely attached to the surface of the battery module through a high heat-conducting aluminum alloy / copper alloy cold plate, and the heat generated by the battery charging and discharging is transferred to the external heat dissipation unit by conduction; the other is the direct contact immersion liquid cooling technology, where the battery cells or modules are completely immersed in a fluorinated liquid or mineral oil with high dielectric strength, and the coolant directly penetrates into the internal gaps of the battery cores through microchannels, and three-dimensional heat dissipation is achieved by using the dual mechanisms of convective heat transfer and phase change heat absorption. In this patent, the battery uses an immersion liquid battery. Although the immersion scheme is used in the embodiments of this patent, the scope of its claims also covers the equivalent technical paths using cold plate indirect cooling.

[0028] The working principle and process of the system of the present invention: (1) Refrigeration mode: When the battery temperature Tmax≥30°C, the system enters the refrigeration mode.

[0029] The liquid-cooling unit 101 outputs a constant-temperature coolant at 21 - 25°C. The coolant enters the battery cassette 602 through the primary pipeline 201, secondary pipeline 202, and tertiary pipeline 203 to cool the battery module.

[0030] After absorbing the battery heat, the temperature of the coolant rises to 35 - 50°C, and it enters the bypass one 401 through the tertiary pipeline 204, secondary pipeline 205, and primary pipeline 206, and flows through the phase change module 300.

[0031] The phase change module 300 absorbs and stores the heat in the coolant. After the temperature of the coolant decreases, it returns to the liquid-cooling unit 101 through the bypass three 403 and the coolant convergence pipeline 501 to complete the cycle.

[0032] (2) Heating mode: When the battery temperature Tmin≤15°C, the system enters the heating mode.

[0033] Preferably, the heat stored in the phase change module 300 is used to heat the coolant. The coolant is pushed by the circulation pump M and flows through the bypass two 402 into the phase change module 300.

[0034] The phase change module 300 releases the stored heat to heat the coolant. The coolant enters the battery cassette 602 through the primary pipeline 201, secondary pipeline 202, and tertiary pipeline 203 to heat the battery module.

[0035] After flowing through the battery module, the temperature of the coolant decreases and it returns to the phase change module 300 through the tertiary pipeline 204, secondary pipeline 205, and primary pipeline 206 to complete the cycle.

[0036] If the heat of the phase change module 300 is insufficient (the temperature of the coolant in bypass three 403 continuously remains below 25°C for 3 minutes), the system automatically switches to the heating mode of the liquid cooling unit 101.

[0037] (3)Self-circulation mode: When the battery temperature Tmax≥18°C and Tmin≤27°C, the system enters the self-circulation mode.

[0038] The condenser and compressor of the liquid cooling unit 101 stop working, and only the water pump is used to drive the circulation of the coolant.

[0039] The coolant circulates between the battery cassette 602 and the liquid cooling unit 101 to take out the heat and maintain the stability of the battery temperature.

[0040] (4)Standby mode When the battery temperature Tmax≥18°C and Tmin≤25°C, the system enters the standby mode.

[0041] The condenser and compressor of the liquid cooling unit 101 stop working, and the water pump runs at a low speed (the flow rate per minute is less than 20 liters) to reduce the energy consumption of the system.

[0042] The working process in the refrigeration mode is as follows: 1. After the system starts, the distributed temperature sensor detects that the battery temperature Tmax≥30°C, and the system automatically enters the refrigeration mode.

[0043] 2. The liquid cooling unit 101 outputs coolant at 21 - 25°C. The coolant enters the battery cassette 602 through the primary pipeline 201, secondary pipeline 202, and tertiary pipeline 203 to cool the battery module.

[0044] 3. After absorbing the battery heat, the temperature of the coolant rises to 35 - 50°C and enters bypass one 401 through the tertiary pipeline 204, secondary pipeline 205, and primary pipeline 206, and flows through the phase change module 300.

[0045] 4. The phase change module 300 absorbs the heat in the coolant and stores it. After the temperature of the coolant decreases, it returns to the liquid cooling unit 101 through bypass three 403 and the coolant convergence pipeline 501 to complete the cycle.

[0046] The working process in the heating mode is as follows: 1. After the system starts, when the distributed temperature sensor detects that the battery temperature Tmin ≤ 15°C, the system automatically enters the heating mode.

[0047] 2. First, use the heat stored in the phase change module 300 to heat the coolant. The coolant is pushed by the circulation pump M and flows through the bypass two 402 into the phase change module 300.

[0048] 3. The phase change module 300 releases the stored heat to heat the coolant. The coolant enters the battery cassette 602 through the primary pipeline 201, secondary pipeline 202, and tertiary pipeline 203 to heat the battery module.

[0049] 4. After flowing through the battery module, the temperature of the coolant decreases and returns to the phase change module 300 through the tertiary pipeline 204, secondary pipeline 205, and primary pipeline 206 to complete the cycle.

[0050] Combined with the above embodiments, the working principle and process of the present invention are further elaborated below: The liquid cooling unit receives the battery temperature information in real time through an integrated temperature sensing network. After the system starts, the sensors distributed at key positions in the battery cassette 602 collect temperature data, and the central controller synchronously calculates the real-time maximum temperature Tmax and minimum temperature Tmin of the battery cluster 601). When the temperature data meets the preset conditions, the controller sends an instruction to the liquid cooling unit 101 through the RS485 communication bus: in the heating mode, the liquid cooling unit 101 starts the electric heater and heats the coolant; in the cooling mode, the liquid cooling unit 101 switches to the compression refrigeration cycle and outputs the cooled coolant. During the whole process, the temperature data is updated every 200 ms, and the liquid cooling unit optimizes the output power in real time according to the dynamically adjusted parameters to ensure that the temperature fluctuation is controlled within ±1°C; the specific processes are described below.

[0051] When the battery is in the working state, the battery temperature will gradually rise.

[0052] Furthermore, if the battery pack temperature sensor detects that Tmax ≥ 30°C, the system automatically triggers the liquid cooling unit cooling mode; at this time, the four-way valve V1, three-way valves V1, V2, V3, V4, and V5 are linked to close bypass 2 and pipeline 503. The complete liquid cooling workflow is as follows: the liquid cooling unit 101 outputs a constant temperature coolant of 21-25°C (PID precise temperature control); the coolant enters the primary pipeline (input) 201, is distributed to enter each secondary pipeline (input) 202, and then enters each tertiary pipeline (input) 203; enters the battery plug box coolant inlet 604 of the submerged battery through the tertiary pipeline (input) 203 to cool the battery; after cooling, the coolant enters the battery plug box coolant outlet 605, and then enters each tertiary pipeline (output) 204, the secondary pipeline (output) 205, and converges into the primary pipeline (output) 206; the coolant passes through the four-way valve V1 and enters the bypass one 401; then the coolant is passed into the phase change module, and the phase change module 300 absorbs the heat in the coolant; then, the coolant passes through the bypass three 403, and enters the coolant convergence pipeline 501 through the three-way valve V2, and then enters the liquid cooling unit 101, completing a whole cycle process.

[0053] Furthermore, in this process, the phase change module 300 absorbs the heat of the coolant and stores the heat. The specific process is as follows: At this time, the coolant has been heated by the battery and the temperature is between 35 and 50°C. The coolant is evenly distributed to each heat transfer tube 302 through the coolant distributor 304. The heat transfer tube increases the heat transfer area through the heat transfer fins 303, and the heat transfer efficiency is further improved. The heat is transferred to the phase change material package 305 wrapped outside the heat transfer tube and the heat transfer fins to store the heat. The role of the heat insulation shell 301 this time is to ensure that the heat of the phase change material package 305 does not leak out.

[0054] This system is designed with an intelligent heating mode for extremely cold environments. When the battery is not in operation, the battery temperature will gradually drop. If the battery temperature Tmin≤15°C is detected, the system will automatically switch to heating mode.

[0055] Further, in the heating mode, the heat stored in the phase change module 300 is preferentially used; the four-way valve V1, the three-way valve V2, the three-way valve V4, and the three-way valve V5 are controlled, and the pipeline 503 and the bypass 403 are closed; at this time, there is no coolant flow in both the coolant converging pipeline 501 and the coolant output pipeline 502. If starting from the circulation pump M to describe the coolant flow at this time, the flow is as follows: The circulation pump M pushes the coolant into the bypass 402, passes through the three-way valves V4 and V5 and enters the primary pipeline (input) 201, and then enters each secondary pipeline (input) 202 and the tertiary pipeline (input) 203; through the tertiary pipeline (input) 203, it enters the coolant inlet 604 of the battery cassette of the immersion battery to heat the battery; after heating, the coolant enters the coolant outlet 605 of the battery cassette, and then enters each tertiary pipeline (output) 204 and the secondary pipeline (output) 205, and converges at the primary pipeline (output) 206; the coolant passes through the four-way valve V1 and enters the bypass one 401, enters the phase change module 300, absorbs the heat stored in the phase change material, and then enters the circulation pump M; thus completing a complete cycle process.

[0056] Further, when the sensor detects that the coolant temperature in the bypass three 403 continuously remains below 25 °C for 3 minutes, the system determines that the heat storage capacity of the phase change module 300 has been used up and cannot meet the battery heating requirement. At this time, the liquid cooling unit will be used for heating.

[0057] Further, when using the liquid cooling unit for heating, the four-way valve V1 is controlled at this time; the three-way valves V2, V3, V4, and V5; the bypass three 403, the bypass two 402, and the bypass one 401 are closed; the coolant converging pipeline 501 and the coolant output pipeline 502 are opened. The complete coolant flow at this time is as follows: The liquid cooling unit 101 electrically heats the coolant; the coolant is sent into the coolant output pipeline 502 through the water pump inside it, enters the primary pipeline (input) 201, each secondary pipeline (input) 202, and each tertiary pipeline (input) 203; through the tertiary pipeline (input) 203, it enters the coolant inlet 604 of the battery cassette of the immersion battery to heat the battery; after heating, the coolant enters the coolant outlet 605 of the battery cassette, and then enters each tertiary pipeline (output) 204 and the secondary pipeline (output) 205, and converges at the primary pipeline (output) 206; passes through the four-way valve V1 and enters the pipeline 503, and finally enters the coolant converging pipeline 501 and is introduced into the liquid cooling unit; thus completing a complete cycle.

[0058] When the battery pack temperature sensor detects that Tmax ≥ 18°C and Tmin ≤ 27°C, the system automatically triggers the self-circulation mode of the liquid cooling unit. In this mode, components such as the condenser and compressor of the liquid cooling unit 101 no longer operate, and only the coolant is circulated in the system through the water pump. At this time, the coolant circulates between the battery cassette and the liquid cooling unit, taking out the heat, which is applicable when the battery charge and discharge rate is relatively small. At this time, control the four-way valve V1; the three-way valves V2, V3, V4, V5; close the bypass three 403, bypass two 402, bypass one 401; open the coolant convergence pipeline 501 and the coolant output pipeline 502. The complete coolant flow at this time is as follows: The liquid cooling unit 101 electrically heats the coolant; the water pump inside it sends the coolant into the coolant output pipeline 502, enters the first-level pipeline (input) 201, each second-level pipeline (input) 202, and each third-level pipeline (input) 203; enters the coolant inlet 604 of the immersion battery in the battery cassette through the third-level pipeline (input) 203 to heat the battery; after heating, the coolant enters the coolant outlet 605 of the battery cassette, then enters each third-level pipeline (output) 204 and second-level pipeline (output) 205, and converges at the first-level pipeline (output) 206; passes through the four-way valve V1 and enters the pipeline 503, and finally enters the coolant convergence pipeline 501 and is introduced into the liquid cooling unit; completing a complete cycle.

[0059] If the battery pack temperature sensor detects that Tmax ≥ 18°C and Tmin ≤ 25°C, the battery temperature is at the best state at this time; the system enters the standby mode. Turn off the condenser and compressor in the liquid cooling unit 101; only keep the water pump in the liquid cooling unit 101 running at a low speed (flow rate less than 20 liters per minute) at this time; reduce the energy consumption of the system.

[0060] In summary, the energy storage system of the present invention can effectively improve the temperature regulation of the battery module in extremely cold environments; the phase change module collects the heat of the coolant in the internal pipeline of the container and transfers this heat back to the pipeline, thus avoiding the over-operation of the liquid cooling unit, reducing the cooling demand of the air conditioner, and improving the overall energy efficiency of the system; the system automatically judges when to start the phase change module to recover heat and adjusts the working mode of the liquid cooling unit according to the temperature change, further optimizing the energy consumption management; the design of the present invention is simple and efficient, with low cost; the system can timely adjust the temperature of the battery module, thereby extending the service life of the battery; the system can store heat in the phase change module, reducing the temperature of the coolant entering the liquid cooling unit in the cooling mode, reducing the energy consumption of the liquid cooling unit, reducing the overall operating cost, and at the same time reducing the impact on the environment through more efficient energy management, meeting the requirements of green environmental protection.

[0061] The foregoing has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and what is described in the above embodiments and the specification is only the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection required by the present invention is defined by the appended claims and their equivalents.

Claims

1. A new type of energy storage system composed of liquid cooling pipes and phase change materials, characterized in that: Comprising: A liquid cooling unit for cooling or heating a coolant; A liquid cooling pipeline system, including multi-stage pipelines, a coolant output pipeline, and a coolant converging pipeline, for the circulating flow of the coolant in the system. The multi-stage pipelines include at least one input pipeline and one output pipeline for distributing the coolant to the battery modules and recovering the coolant. The specific connection mode of the liquid cooling pipeline system and the multi-stage bypass system can be adjusted according to actual requirements; A battery cluster composed of multiple battery modules, installed in a battery rack. The battery modules are connected to the liquid cooling pipeline system through the coolant inlets and outlets of the battery plug-in boxes; A phase change module for storing and releasing the heat in the coolant, including a heat-insulating shell, heat transfer pipes, heat transfer fins, a coolant distributor, and a phase change material encapsulation body. The phase change material encapsulation body is filled with a paraffin or fatty acid-based phase change material and doped with 5%-20% of aluminum powder or graphite powder to improve the thermal conductivity; A multi-stage bypass system, including at least one bypass, for controlling the path of the coolant flowing through the phase change module; A valve system, including at least one four-way valve and multiple three-way valves, for regulating the flow direction of the coolant; A circulation pump for promoting the circulating flow of the coolant in the system; Among them, the liquid cooling unit, the liquid cooling pipeline system, the phase change module, and the multi-stage bypass system work together. By recovering the heat of the coolant heated by the battery and storing it in the phase change module, the heat stored in the phase change module is preferentially used for heating when the battery temperature is low, reducing the energy consumption of the liquid cooling unit and improving the energy efficiency of the system.

2. The energy storage system according to claim 1, characterized in that: The liquid cooling pipeline system adopts a multi-stage circulation architecture. The coolant enters the battery plug-in box through the multi-stage pipelines, cools or heats the battery modules, and outputs the coolant to the liquid cooling unit or the phase change module through the multi-stage pipelines.

3. The energy storage system according to claim 1, characterized in that: The multi-stage bypass system controls the path of the coolant flowing through the phase change module through valves to achieve the storage and release of heat, specifically including: In the refrigeration mode, the coolant flows through at least one bypass and enters the phase change module, and the phase change material absorbs the heat in the coolant and stores it; In the heating mode, the coolant flows through at least one bypass and enters the phase change module, and the phase change material releases the stored heat to heat the coolant.

4. The energy storage system according to claim 1, characterized in that: The liquid cooling unit automatically switches the working mode according to the battery temperature, including a refrigeration mode, a heating mode, a self-circulation mode, and a standby mode. Specifically: When the battery temperature Tmax≥N1, the system enters the refrigeration mode; When the battery temperature Tmin≤N2, the system enters the heating mode; When the battery temperature Tmax≥N3 and Tmin≤N4, the system enters the self-circulation mode; When the battery temperature Tmax≥N5 and Tmin≤N6, the system enters the standby mode; Among them, N1, N2, N3, N4, N5, N6 are preset temperature values, and N1>N3>N5, N2<N4<N6. The temperature values N1-N6 can be adjusted according to the battery type and environmental conditions.

5. The energy storage system according to claim 1, characterized in that: The heat-insulating shell of the phase change module adopts a double-layer galvanized steel plate sandwich structure, and the inside is filled with rock wool or glass wool as a heat-insulating layer, and is installed by bolt connection to reduce the influence of the external environment on the internal temperature of the module.

6. A new energy storage method combining liquid cooling pipes and phase change materials, characterized in that: Including the following steps: When the battery temperature Tmax ≥ N1, the system enters the refrigeration mode, and the coolant flows through the phase change module to store heat; When the battery temperature Tmin ≤ N2, the system enters the heating mode, and preferentially uses the heat stored in the phase change module to heat the battery; When the battery temperature Tmax ≥ N3 and Tmin ≤ N4, the system enters the self-circulation mode, and the coolant circulates between the battery cassette and the liquid cooling unit; When the battery temperature Tmax ≥ N5 and Tmin ≤ N6, the system enters the standby mode to reduce energy consumption; Among them, N1, N2, N3, N4, N5, and N6 are preset temperature values, and N1 > N3 > N5, N2 < N4 < N6. The temperature values N1 - N6 can be adjusted according to the battery type and environmental conditions.

7. The energy storage method according to claim 6, characterized in that: In the refrigeration mode, when the coolant flows through the phase change module, the phase change material absorbs the heat in the coolant and stores it. Specifically: After the coolant is heated by the battery, the temperature is between 35 and 50 °C, and it flows through the coolant distributor and is evenly distributed into the heat transfer tubes; The heat transfer tubes increase the heat dissipation area through heat transfer fins, transfer the heat to the phase change material package, and achieve heat storage.

8. The energy storage method according to claim 6, characterized in that: In the heating mode, when the coolant flows through the phase change module, the phase change material releases the stored heat to heat the coolant. Specifically: The coolant is pushed by the circulation pump and flows through at least one bypass into the phase change module; The phase change material package releases heat to heat the coolant, and the coolant flows through the battery cassette to heat the battery module.

9. The energy storage method according to claim 6, characterized in that: In the self-circulation mode, the condenser and compressor of the liquid cooling unit stop working, and only the coolant is circulated by the water pump. Specifically: The coolant circulates between the battery cassette and the liquid cooling unit, taking out the heat; The system adjusts the coolant flow path through the valve system to prevent the coolant from flowing through the phase change module.

10. Application of a new type of energy storage system composed of liquid cooling pipes and phase change materials in extremely cold environments, characterized in that: The system stores and releases heat through the phase change module, reduces the energy consumption of the liquid cooling unit, and improves the adaptability and energy efficiency of the system in extremely cold environments. Specifically: In the scenario without external energy supply, the heat stored in the phase change module can be used as an emergency heat source to ensure that the battery maintains the basic working temperature in extremely low temperature environments; Reduce the working load of the liquid cooling unit through the heat energy circulation mechanism, and extend the service life of the core components such as the battery pack in the battery compartment, the compressor, condenser, and electric heater of the liquid cooling unit.

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