Method for reducing operation temperature difference of energy storage system

Abstract

The invention relates to the field of new energy storage, and discloses a method for reducing the operation temperature difference of an energy storage system, and the method comprises the following steps: S1, coating a heat-conducting adhesive with high heat-conducting property between a battery pack and a heat dissipation liquid cooling plate; s2, adjusting the fluid channel design of the liquid cooling plate; s3, the lift of a water pump in the liquid cooling system is adjusted, and auxiliary supercharging equipment is configured; s4, adjusting the layout of a cooling liquid pipeline, and optimizing the curvature and the material of the pipeline; and S5, adjusting the internal connection bar structure of the battery PACK, and adding a soaking and auxiliary heat dissipation design. The heat-conducting glue with high heat-conducting property is coated between the battery pack and the heat-dissipating liquid-cooling plate, and a uniformly-distributed latticed coating mode is adopted, so that the heat conduction efficiency is effectively improved, the heat resistance is reduced due to the high heat-conducting coefficient of the heat-conducting glue and the accurately-controlled thickness, and the heat generated by the battery pack can be quickly transferred to the heat-dissipating liquid-cooling plate; therefore, the temperature difference in the system is obviously reduced, and the phenomenon of local overheating is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy storage technology, and in particular to a method for reducing the operating temperature difference of an energy storage system. Background Art

[0002] With the rapid development of electric vehicles, energy storage power stations and other fields, the safety and reliability of energy storage systems have become core concerns. Liquid-cooled energy storage battery systems are widely used due to their good heat dissipation performance, but the following problems are common in existing technologies, which seriously affect the operating efficiency of the system and battery life: In traditional liquid-cooled energy storage systems, ordinary thermal conductive materials or unoptimized filling methods are usually used between the battery pack and the heat dissipation liquid cold plate. This method has the disadvantages of high thermal resistance and low heat conduction efficiency in practical applications. In particular, improper material thickness control or uneven coating will make it difficult for the heat generated by the battery to be evenly transferred to the heat dissipation liquid cold plate, thereby causing local overheating and affecting the performance and life of the battery. In addition, excessively high thermal resistance will also aggravate the fluctuation of temperature difference and cause unstable operation of the battery pack.

[0003] The fluid channel design of traditional liquid cooling plates mostly adopts a single flow channel or a simple straight design. Although this design has a low manufacturing cost, the contact area between the fluid and the inner wall of the liquid cooling plate is limited, and the heat exchange efficiency is low. At the same time, the inner wall of the liquid cooling plate is usually a smooth structure without special treatment, which further limits the improvement of the fluid heat exchange effect. In high power density energy storage systems, the existing liquid cooling plate design is difficult to meet the needs of efficient heat dissipation, which easily leads to heat dissipation bottlenecks in system operation.

[0004] The existing design of the coolant circulation system often has sharp turns and large local resistance in the piping layout. This layout will produce significant friction loss and pressure attenuation when the liquid flows, resulting in insufficient coolant flow rate at the far end. In addition, traditional piping materials such as metal pipes or ordinary plastic pipes have high surface roughness, which increases fluid resistance and energy consumption during the flow of coolant. Especially in complex cooling circuits, excessive flow resistance will significantly reduce cooling efficiency, thereby affecting the overall heat dissipation performance of the energy storage system. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a method for reducing the operating temperature difference of an energy storage system, thereby solving the problems of low heat conduction efficiency, insufficient heat exchange performance and excessive coolant flow resistance in existing liquid-cooled energy storage battery systems.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: A method for reducing the operating temperature difference of an energy storage system comprises the following steps: S1: Apply high thermal conductivity thermal conductive glue between the battery pack and the heat dissipation liquid cold plate; S2: Adjust the fluid channel design of the liquid cooling plate; S3: Adjust the water pump head in the liquid cooling system and configure auxiliary boosting equipment; S4: Adjust the coolant pipeline layout and optimize the pipeline curvature and material; S5: Adjust the internal connection row structure of the battery PACK and add heat distribution and auxiliary heat dissipation design.

[0007] Preferably, in step S1, the thermal conductivity of the thermally conductive adhesive is not less than 6 W / m·K, the coating thickness is 0.1-0.2 mm, and the thermally conductive adhesive is distributed in a grid shape on the contact surface, with a grid point spacing of 5-10 mm.

[0008] Preferably, in step S2, the diameter of the fluid channel of the liquid cooling plate is in the range of 2-5 mm, the inner wall is provided with micro grooves, and the depth of the micro grooves is 50-200 μm; the liquid cooling plate is made of copper-aluminum composite material.

[0009] Preferably, the water pump head in step S3 is greater than 20m, and the flow rate range is 2-4L / min; The water pump impeller structure is a double-layer impeller, the number of blades is 6-12, and the blade angle is 15-30°.

[0010] Preferably, in step S4, the coolant pipeline is made of polytetrafluoroethylene material with a pipe diameter ranging from 8 to 15 mm.

[0011] Preferably, the connecting bar of the battery PACK in step S5 is made of silver-plated copper material, the coating thickness is 5-8 μm, and the cross-sectional area of ​​the connecting bar is 50-150 mm².

[0012] Preferably, in step S5, a multi-layer stacked heat-conducting structure is added in the battery PACK, and the heat-conducting structure material is a high-thermal-conductivity carbon composite material with a thermal conductivity coefficient of 7-10 W / m·K.

[0013] Preferably, in step S5, a vapor chamber is arranged in the battery PACK, the vapor chamber is filled with liquid metal or phase change material, the melting point of the phase change material is in the range of 45-65° C., and heat conducting sheets are provided at both ends of the connecting row for auxiliary heat dissipation.

[0014] Preferably, the fluid channel in step S2 includes but is not limited to a multi-branch parallel flow channel or a spiral flow channel.

[0015] Preferably, the auxiliary boosting equipment in step S3 is an auxiliary boosting pump, and the lift of the auxiliary boosting pump is 10-15m.

[0016] The present invention provides a method for reducing the operating temperature difference of an energy storage system. It has the following beneficial effects: 1. The present invention effectively improves the heat conduction efficiency by coating a thermally conductive adhesive with high thermal conductivity between the battery pack and the heat dissipation liquid cold plate and adopts a uniformly distributed grid-shaped coating method. The high thermal conductivity and precisely controlled thickness of the thermally conductive adhesive reduce thermal resistance, so that the heat generated by the battery pack can be quickly transferred to the heat dissipation liquid cold plate, thereby significantly reducing the temperature difference inside the system and reducing the occurrence of local overheating.

[0017] 2. The present invention optimizes the design of the fluid channel of the liquid cooling plate, combines the structure of multi-branch parallel flow channels or spiral flow channels and the inner wall micro-groove treatment, which not only increases the contact area between the coolant and the liquid cooling plate, but also enhances the heat exchange effect of the fluid.

[0018] 3. The present invention optimizes the layout design of the coolant pipeline and effectively reduces the friction resistance and local pressure loss of the coolant during the flow process by adopting a polytetrafluoroethylene material pipeline with smooth bends and a low friction coefficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the method steps of the present invention. DETAILED DESCRIPTION

[0020] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] Example: Please see attached Figure 1 , an embodiment of the present invention provides a method for reducing the operating temperature difference of an energy storage system, comprising the following steps: S1: Apply high thermal conductivity thermal conductive adhesive between the battery pack and the heat dissipation liquid cold plate; the thermal conductivity of the thermal conductive adhesive is not less than 6W / m·K, the coating thickness is 0.1-0.2mm, and the thermal conductive adhesive is distributed in a grid shape on the contact surface, and the grid point spacing is 5-10mm.

[0022] Specifically, the contact surface between the battery pack and the heat dissipation liquid cold plate is roughened, such as by sandblasting or laser etching technology, to form a microstructure with a surface roughness in the range of 10-30μm. This microscopic rough structure can effectively improve the adhesion of the thermal conductive adhesive and increase the contact area, which helps to improve the heat conduction efficiency.

[0023] The selection of thermal conductive adhesive is crucial. Materials with high thermal conductivity and that meet the thermal management requirements of the energy storage system should be selected. A composite thermal conductive adhesive with a silicone matrix and doped with high thermal conductivity ceramic particles (such as boron nitride or aluminum oxide) is preferred. Its thermal conductivity must be no less than 6W / m·K to ensure that the heat generated by the battery pack can be quickly transferred to the heat dissipation liquid cold plate. The thermal conductive adhesive must be vacuum degassed before use to remove internal bubbles and prevent uneven thermal resistance after coating.

[0024] During the coating process, it is recommended to use automated spraying equipment to precisely control the thermal conductive adhesive to ensure that the coating thickness is within the range of 0.1-0.2mm. To achieve uniform distribution, a regular grid spraying method can be used, and the spacing of the grid points is controlled between 5-10mm. The advantage of this distribution pattern is that it can cover most of the heat conduction path while avoiding material waste or increased thermal resistance caused by excessive coating. After spraying, use a mechanical pressing device to fix the battery pack and liquid cooling plate and apply uniform pressure to ensure that the thermal conductive adhesive is in full contact with the surfaces of both and eliminate possible air gaps.

[0025] The key to this implementation is to precisely control the thickness and distribution pattern of the thermally conductive adhesive so that heat can be efficiently and evenly transferred from the battery pack to the heat dissipation liquid cold plate. After being processed by the above method, the heat dissipation liquid cold plate can quickly take away the heat generated by the battery pack, effectively reduce the battery operating temperature difference, and reduce local overheating, thereby extending the service life of the battery pack and improving the operating reliability of the overall energy storage system.

[0026] S2: Adjust the fluid channel design of the liquid cooling plate; the diameter of the fluid channel of the liquid cooling plate is 2-5 mm, the inner wall is provided with micro grooves, and the depth of the micro grooves is 50-200 μm; the liquid cooling plate is made of copper-aluminum composite material. The fluid channel includes but is not limited to multi-branch parallel flow channels or spiral flow channels.

[0027] Specifically, when implementing the present invention, the fluid channel design of the liquid cooling plate is the core link to optimize heat conduction and fluid dynamics performance. First, the fluid channel structure of the liquid cooling plate is designed according to the thermal distribution and cooling requirements of the battery pack. The diameter of the channel is controlled within the range of 2-5mm. This range can reduce the resistance to liquid flow while ensuring sufficient flow, while increasing the contact area between the coolant and the inner wall of the liquid cooling plate, thereby enhancing the heat exchange efficiency.

[0028] In order to further improve the heat dissipation capacity of the liquid cooling plate, a micro-groove structure is designed on the inner wall of the channel, and the depth of the micro-groove is controlled between 50-200μm. These micro-grooves are made by precision processing technology (such as laser etching or CNC micro-machining), which can significantly increase the surface area of ​​the inner wall of the liquid cooling plate, enhance the heat exchange effect between the coolant and the inner wall, and optimize the fluid boundary layer behavior to promote faster heat transfer to the surface of the liquid cooling plate.

[0029] The fluid channel type of the liquid cooling plate can be selected as a multi-branch parallel flow channel or a spiral flow channel according to system requirements. The multi-branch parallel flow channel has the advantages of small flow resistance and uniform distribution of coolant, which is suitable for situations where the battery pack size is large and the heat distribution is relatively uniform. The spiral flow channel can maximize the use of the channel length to extend the contact time of the coolant, which is suitable for the heat dissipation needs of local high-temperature areas. In the specific implementation, the computational fluid dynamics (CFD) simulation tool can be combined to optimize the design of the flow velocity distribution, pressure loss and temperature gradient of the coolant in the flow channel to determine the optimal flow channel layout.

[0030] The material of the liquid cooling plate is copper-aluminum composite material. Through reasonable composite ratio and processing technology, it combines the high thermal conductivity of copper and the lightweight advantage of aluminum. The thermal conductivity of copper-aluminum composite material can reach more than 200-300W / m·K, and it has good corrosion resistance and can maintain stable performance in long-term operation.

[0031] When processing the liquid cooling plate, CNC precision processing equipment is used to ensure that the dimensional accuracy of the fluid channel is within ±0.1mm, and pressure resistance and flow tests are carried out to verify the heat dissipation performance and reliability of the processed liquid cooling plate under actual operating conditions.

[0032] Through the fluid channel design of the liquid cooling plate, the coolant can efficiently remove the heat generated by the battery pack during operation, reduce the temperature difference inside the system, and reduce the flow resistance and energy consumption during the coolant circulation process.

[0033] S3: Adjust the water pump head in the liquid cooling system and configure auxiliary boosting equipment; the water pump head is greater than 20m, and the flow range is 2-4L / min; the water pump impeller structure is a double-layer impeller, the number of blades is 6-12, and the blade angle is 15-30°. The auxiliary boosting equipment is an auxiliary boosting pump, and the auxiliary boosting pump head is 10-15m.

[0034] Specifically, when implementing the present invention, in order to ensure that the coolant of the liquid cooling system can maintain uniform flow and sufficient pressure throughout the entire circulation path, it is necessary to optimize the water pump head and add auxiliary boosting equipment. The head of the system's main water pump must be greater than 20m, and the flow range must be controlled at 2-4L / min to meet the cooling requirements of the energy storage battery system. The design of the water pump head is based on the total pressure loss estimation in the system coolant circuit, including the flow resistance in the liquid cooling plate, the pipeline friction resistance, and the local resistance.

[0035] The impeller of the main water pump adopts a double-layer impeller design, with 6-12 blades and the bending angle of the blades controlled in the range of 15-30°. The advantage of the double-layer impeller structure is that it can significantly improve the pump head and efficiency while reducing fluid turbulence and vibration. The number and angle of blades are selected based on fluid dynamics simulation results to ensure stable performance at different coolant flow rates. The pump housing is made of corrosion-resistant materials (such as stainless steel or composite materials) to meet the chemical stability requirements of the coolant during long-term operation.

[0036] To further ensure the uniformity of the coolant pressure in the remote cooling circuit, an auxiliary booster pump is added to the remote area of ​​the pipeline. The head of the auxiliary booster pump is designed to be 10-15m, which can compensate for the deficiency of the main water pump after the remote coolant pressure decays, thereby maintaining a stable flow rate of the coolant in the entire system. The auxiliary booster pump can be linked with the main water pump through the intelligent control module, and its operating parameters can be dynamically adjusted according to the real-time monitored pipeline pressure and flow rate data.

[0037] The operation of the entire liquid cooling system is automatically managed through pressure and flow monitoring devices. High-precision pressure sensors and flow meters are installed at key nodes of the coolant pipeline (such as the inlet, outlet and remote area of ​​the liquid cooling plate) to monitor the operating status of the system in real time. The monitoring data is analyzed by the central control module and used to dynamically adjust the working status of the main water pump and auxiliary booster pump to ensure uniform distribution of the coolant.

[0038] S4: Adjust the coolant pipeline layout and optimize the pipeline curvature and material; the coolant pipeline is made of polytetrafluoroethylene material with a pipe diameter range of 8-15mm.

[0039] Specifically, when implementing the present invention, in order to ensure smooth flow of the coolant in the pipeline and reduce fluid resistance, the layout and material selection of the coolant pipeline need to be optimized. The coolant pipeline preferably uses polytetrafluoroethylene (PTFE) material because it has a low friction coefficient, high corrosion resistance and excellent high temperature resistance, and can maintain stable performance under high temperature and high pressure conditions of the energy storage system. In addition, the surface smoothness of the PTFE pipeline can significantly reduce the pressure drop caused by friction during the flow of the coolant.

[0040] The diameter range of the pipeline is designed to be 8-15mm to take into account both flow demand and flow resistance control. Pipes with larger diameters (close to 15mm) are suitable for trunk pipes to ensure the total flow demand of the coolant; smaller diameter pipes (close to 8mm) can be used for branch pipes to maintain sufficient flow rate during diversion. This combination of trunk and branch pipe diameter design can effectively optimize the fluid distribution of the entire coolant circuit.

[0041] The layout of the pipeline should avoid 90° sharp turns or too many joints, which are prone to turbulence and local pressure loss. It is recommended to adopt a smooth bend design, and the radius of curvature of the pipeline should be at least 5 times the diameter of the pipe to minimize the resistance to liquid flow. In the actual layout process, computational fluid dynamics (CFD) is used to simulate the flow of coolant in the pipeline, optimize the bending angle and length of the pipeline, and minimize the pressure loss.

[0042] High-strength seals (such as metal or polymer seals) are required at pipeline connections to prevent coolant leakage, and flow sensors and pressure sensors are installed at key nodes (such as branch ports or bending points) to monitor the fluid flow status in real time. To further improve the stability and durability of the pipeline, a pressure test can be performed after the layout is completed to ensure that the pipeline can withstand the maximum pressure value during operation.

[0043] S5: Adjust the internal connection row structure of the battery PACK, and add heat spreader and auxiliary heat dissipation design. The connection row of the battery PACK is made of silver-plated copper material with a coating thickness of 5-8μm and a cross-sectional area of ​​50-150mm². A multi-layer stacked thermal conductive structure is added to the battery PACK. The thermal conductive structure material is a high thermal conductivity carbon composite material with a thermal conductivity coefficient of 7-10W / m·K. A heat spreader is arranged in the battery PACK, and the heat spreader is filled with liquid metal or phase change material. The melting point range of the phase change material is 45-65°C, and heat conductive sheets are set at both ends of the connection row for auxiliary heat dissipation.

[0044] Specifically, first of all, the electrical connection bar in the battery PACK is improved to reduce resistance and heat generation. The connection bar is made of silver-plated copper material with a coating thickness of 5-8μm, which can significantly reduce contact resistance and maintain good conductivity during long-term operation. The cross-sectional area of ​​the connection bar is designed to be between 50-150mm², and is selected according to the current density requirements of the battery pack, which not only ensures sufficient conductivity during charging and discharging, but also avoids increasing the system weight due to excessive cross-sectional area.

[0045] Add a multi-layer stacked heat-conducting structure inside the battery PACK. The heat-conducting structure material uses a high-thermal-conductivity carbon composite material with a thermal conductivity coefficient in the range of 7-10W / m·K, which can quickly transfer the heat from the local overheating area to the heat dissipation device. These heat-conducting structures can cover multiple battery cells at the same time through a stacked design to evenly disperse the heat generated during battery operation. The installation of the stacked structure requires precise alignment of the battery cell position and fixation with high-strength thermal adhesive to ensure stability during long-term use.

[0046] In order to further balance the heat distribution, a heat spreader is arranged in the battery PACK. The core material of the heat spreader is liquid metal (such as gallium-based alloy) or phase change material, which has excellent thermal conductivity and can quickly absorb and diffuse the heat of local hot spots. The melting point range of the phase change material is 45-65°C, which is suitable for the normal operating temperature range of energy storage batteries. When the battery temperature rises to the melting point of the material, the phase change material completes the phase change by absorbing heat, significantly reducing the temperature rise in the overheated area; when the temperature drops, the material re-solidifies and releases heat to maintain the stability of the overall temperature.

[0047] The shape of the heat spreader is customized according to the arrangement of the battery pack. After the liquid metal or phase change material is filled inside, the sealing structure is used to prevent material leakage. At the same time, heat conducting plates are set at both ends of the heat spreader as auxiliary heat dissipation devices. The heat conducting plates are usually made of aluminum alloy or copper-aluminum composite materials and are connected to the liquid cooling system to further quickly remove the heat conducted in the heat spreader.

[0048] By adjusting the connection row structure and adding heat spreader and auxiliary heat dissipation design, the present invention significantly reduces the internal thermal resistance of the battery pack and effectively alleviates local overheating. The synergistic effect of the multi-layer heat conductive structure and the heat spreader not only improves the overall thermal management efficiency of the battery pack, but also extends the service life of the battery pack, providing an important guarantee for the efficient operation of the energy storage system.

[0049] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for reducing the operating temperature difference of an energy storage system, characterized in that: The following steps are involved: S1: Apply high thermal conductivity thermal conductive glue between the battery pack and the heat dissipation liquid cold plate; S2: Adjust the fluid channel design of the liquid cooling plate; S3: Adjust the water pump head in the liquid cooling system and configure auxiliary boosting equipment; S4: Adjust the coolant pipeline layout and optimize the pipeline curvature and material; S5: Adjust the internal connection row structure of the battery PACK and add heat distribution and auxiliary heat dissipation design.

2. A method for reducing the operating temperature difference of an energy storage system according to claim 1, characterized in that: In the step S1, the thermal conductivity of the thermal conductive adhesive is not less than 6 W / m·K, the coating thickness is 0.1-0.2 mm, and the thermal conductive adhesive is distributed in a grid shape on the contact surface, with a grid point spacing of 5-10 mm.

3. A method for reducing the operating temperature difference of an energy storage system according to claim 1, characterized in that: In step S2, the diameter of the fluid channel of the liquid cooling plate is in the range of 2-5 mm, the inner wall is provided with micro grooves, and the depth of the micro grooves is 50-200 μm; the material of the liquid cooling plate is a copper-aluminum composite material.

4. A method for reducing the operating temperature difference of an energy storage system according to claim 1, characterized in that: In step S3, the water pump head is greater than 20m, and the flow rate range is 2-4L / min; The water pump impeller structure is a double-layer impeller, the number of blades is 6-12, and the blade angle is 15-30°.

5. A method for reducing the operating temperature difference of an energy storage system according to claim 1, characterized in that: In step S4, the coolant pipeline is made of polytetrafluoroethylene material, and the diameter ranges from 8 to 15 mm.

6. A method for reducing the operating temperature difference of an energy storage system according to claim 1, characterized in that: In the step S5, the connecting bar of the battery PACK is made of silver-plated copper material, the coating thickness is 5-8 μm, and the cross-sectional area of ​​the connecting bar is 50-150 mm².

7. A method for reducing the operating temperature difference of an energy storage system according to claim 1, characterized in that: In the step S5, a multi-layer stacked heat-conducting structure is added in the battery PACK, and the heat-conducting structure material is a high-thermal-conductivity carbon composite material with a thermal conductivity coefficient of 7-10 W / m·K.

8. A method for reducing the operating temperature difference of an energy storage system according to claim 1, characterized in that: In step S5, a vapor chamber is arranged in the battery PACK, and the vapor chamber is filled with liquid metal or phase change material, the melting point of the phase change material is in the range of 45-65° C., and heat conducting sheets are arranged at both ends of the connecting row to assist in heat dissipation.

9. A method for reducing the operating temperature difference of an energy storage system according to claim 1, characterized in that: The fluid channel in step S2 includes but is not limited to a multi-branch parallel flow channel or a spiral flow channel.

10. A method for reducing the operating temperature difference of an energy storage system according to claim 1, characterized in that: The auxiliary boosting device in step S3 is an auxiliary boosting pump, and the lift of the auxiliary boosting pump is 10-15m.

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