Electrochemical Peltier refrigeration device and copper-ammonia complex binary solution used in the device

Abstract

This invention discloses an electrochemical Peltier cooling device and a copper-ammonia complex ion binary solution used in the device, relating to the field of electrochemical Peltier cooling technology. The copper-ammonia complex ion binary solution is characterized by comprising a transition metal salt, an auxiliary ligand, an organic solvent, and deionized water; the transition metal salt comprises CuCl and CuCl2, the auxiliary ligand is NH3, and the organic solvent is N,N-dimethylformamide. The cooling device comprises a reactor, a radiator, and a cooler. The reactor comprises a reaction chamber, a cold-end current collector, a cold-end electrode, a hot-end current collector, a hot-end electrode, and a porous membrane. This invention achieves synergistic optimization of high reversible endothermic capacity and high-temperature cooling response at the electrolyte level, and integrates the reactor, cooler, radiator, and circulation path in the device design.

Description

Technical Field

[0001] This invention relates to the field of electrochemical Peltier refrigeration technology, specifically to an electrochemical Peltier refrigeration device and a copper-ammonia complex ion binary solution for the device. Background Technology

[0002] With the increasing integration of microelectronic devices, the heat flux density of electronic devices such as chips and power devices is growing exponentially, with local hotspot temperatures reaching over 150°C. Furthermore, for every 10°C increase in temperature, the failure rate of electronic components increases by 50%, severely impacting device performance, reliability, and lifespan. Traditional air cooling requires significant space for heat sinks, generates noise during operation, and consumes additional electrical energy. Liquid cooling devices are complex, bulky, heavy, have low reliability, and high maintenance costs, making them unsuitable for precise cooling of local hotspots. While solid-state thermoelectric cooling technology based on the Peltier effect offers advantages such as small size and no moving parts, it suffers from low efficiency (COP typically <0.8 at room temperature), reliance on rare-earth materials like bismuth telluride, and high costs, limiting its large-scale application. Therefore, developing novel, high-efficiency cooling devices is crucial for the development of electronic devices.

[0003] Existing technologies include refrigeration devices based on liquid circulation and the entropy-thermal effect of electrochemical redox reactions. For example, patent document CN108895581A discloses an electrochemical refrigeration and heating device based on a flow battery, which achieves heating and cooling through an exothermic and an endothermic stack, respectively. This scheme can achieve continuous heat exchange, but it adopts a dual-stack structure with the endothermic and exothermic stacks set separately, and requires an external circulation device, liquid storage component, and heat exchange unit. The system has many components and a complex structure, making it more suitable for system-level heat and cold control scenarios. It is difficult to directly meet the needs of chips, power devices, and other local hot spots for miniaturized, integrable, and fast-response refrigeration devices. Patent document US11926783B2 discloses an electrochemical redox refrigeration method in which an electrochemical refrigerant flows sequentially through a first electrode and a second electrode in a flow channel, and undergoes oxidation and reduction reactions at the two electrodes under the action of an applied potential, thereby generating a cooling effect at one electrode and a heating effect at the other electrode. The technology also proposes that Joule heat and hot-end losses can be removed from the vicinity of the cooling electrode by the flow of electrolyte, and that the low-temperature electrolyte flowing out of the cooling electrode can be introduced into the cold-side heat exchanger, while the electrolyte flowing out of the heating electrode can be introduced into the hot-side heat exchanger, to achieve continuous cooling. However, such devices mainly focus on general electrochemical refrigerants and flow-channel electrode structures, without addressing the specific needs of high thermoelectric potential redox reaction couples, low specific heat electrolytes, and local hot spot cooling in electronic devices. The temperature drop of a single cell is only 50 mK.

[0004] Therefore, although existing electrochemical refrigeration devices have verified the feasibility of using the entropy heat of electrochemical redox reactions for refrigeration, there are still problems such as complex device structure, insufficient integration capability of local hot spots, lack of optimization of electrolyte thermal properties for refrigeration needs, and insufficient coupling between cold end heat absorption, hot end heat dissipation and the object to be cooled.

[0005] Electrochemical Peltier effect (EPC)-based refrigeration technology has become a potential solution to the heat dissipation problem of electronic devices due to its advantages such as high cooling performance (COP), low cost, and simple structure. EPC refrigeration technology drives a thermal redox ion couple (such as [Fe(CN)6]) with an external current. 4- / 3- Fe 2+ / 3+ Redox reactions occur at both electrodes, resulting in endothermic and exothermic phenomena at the anode and cathode interfaces, respectively. Effective cooling is achieved by utilizing the endothermic effect of the electrolyte at the low-temperature end. The key to this technology is: (1) The thermoelectric reaction ion couple system needs to have a high temperature coefficient (…). α Due to the thermodynamic driving force of the system ( Q = αTI Thermoelectric potential of thermoelectric ion pairs ( α = ΔS / nF (1) The intensity of the control will change the internal properties of the device and affect the cooling performance; (2) The electrolyte needs to have a low specific heat capacity. c p ). The specific heat capacity of the electrolyte can affect the temperature drop and response speed corresponding to the unit net heat absorption; (3) EPC refrigeration equipment should have the advantage of simple structure, which is conducive to large-scale and scaled application. At present, there is no electrochemical Peltier refrigeration technology that can meet the above three technical requirements at the same time and is suitable for low-energy active cooling of local hot spots of electronic devices (such as chips and power devices) with local temperatures as high as 150°C or above.

[0006] Therefore, this patent application is filed. Summary of the Invention

[0007] The purpose of this invention is to provide a copper-ammonia complex ion binary solution for electrochemical Peltier cooling, and also to provide an electrochemical Peltier cooling device using the aforementioned copper-ammonia complex ion binary solution as the electrolyte. This device is designed synergistically to address the specific cooling needs of high thermoelectric potential redox couples, low specific heat electrolytes, and localized hot spots in electronic devices. It utilizes a copper-ammonia complex redox couple and introduces N,N-dimethylformamide (DMF) to construct a water-DMF binary solution as the working solution. By controlling the solvation environment of the copper-ammonia complex ions, the thermoelectric potential coefficient of the system is increased, the average specific heat capacity of the electrolyte is reduced, and the endothermic phase change of NH3 at the cold end enhances the net endothermic capacity at the cold end. Therefore, in terms of device structure, the reactor, cooler, heat sink, and circulation path are integrated into a single design; and at the electrolyte level, high reversible endothermic capacity and high-temperature response are synergistically optimized, making it more suitable for low-energy active cooling of localized hot spots in electronic devices.

[0008] This invention is achieved through the following technical solution: The first objective of this invention is to provide a copper-ammonia complex ion binary solution for electrochemical Peltier cooling, the solution comprising a transition metal salt, an auxiliary ligand, an organic solvent, and deionized water; The transition metal salt includes CuCl and CuCl2, the auxiliary ligand is NH3, and the organic solvent is N,N-dimethylformamide; The concentration of CuCl in the solution is 0.1–0.2 mol / L, the concentration of CuCl2 is 0.1–0.2 mol / L, the concentration of NH3 is 1–4 mol / L, and the concentration of N,N-dimethylformamide is 0.5–3 mol / L.

[0009] Patent document CN 120300206 A discloses a method using [Cu(NH3)2]. + and [Cu(NH3)4] 2+ This patent describes an N-type thermal battery electrolyte for redox reaction couples, but it primarily focuses on [Cu(NH3)2]. + / [Cu(NH3)4] 2+ The feasibility of redox couples in the field of thermoelectric power generation is questionable, but they are applied to the field of thermoelectric power generation rather than the field of refrigeration. This is because the fields of refrigeration and thermoelectric conversion have the following differences: (1) Difference in essential working principle: There is an essential difference in the working principle between refrigeration operation and thermoelectric conversion operation, even though [Cu(NH3)2] is used. + / [Cu(NH3)4] 2+The redox reaction couple, CN120300206A, mainly targets low-grade heat energy recovery and thermoelectric power generation scenarios in the thermoelectric conversion field. Its device operation depends on the external temperature difference and uses the redox effect to convert heat energy into electrical energy. The refrigeration field is for active refrigeration scenarios for electronic devices, local heat sources or small enclosed spaces. The goal is to drive the EPC effect under the action of external current, actively generate the cold end heat absorption effect, and achieve rapid cooling of the target heat source. That is, the technology in CN120300206A belongs to the temperature difference driven thermoelectric power generation system, which aims to achieve temperature difference → electrical energy output. The current driven electrochemical Peltier refrigeration system aims to achieve electrical energy → cold energy / directional heat transport. (2) Differences in operation and performance indicators: In addition to the open circuit voltage, the thermoelectric system also needs to pay attention to the output power density and thermoelectric conversion efficiency under different temperature difference conditions, that is, how to generate higher voltage and working current under the same temperature difference conditions. The EPC refrigeration system needs to work under external current or voltage conditions. Its key parameter is COP, that is, how to generate greater heat absorption and cooling capacity under the same energy input conditions.

[0010] If the electrolyte in the existing patent document CN120300206A is directly applied to the EPC refrigeration field, the following technical difficulties exist: (1) The reversible heat absorption capacity of the cold end of the EPC device and the thermoelectric potential coefficient of the electrolyte are different. α Closely related, in CN120300206A α The maximum value is only 2.30 mV / K, which is insufficient for EPC devices designed for cooling to generate a sufficiently large net cooling capacity at low input power, resulting in limited COP and temperature drop performance.

[0011] (2) EPC equipment also requires the electrolyte to have a low specific heat capacity. c p To enhance the temperature drop response corresponding to a unit of heat absorption, the system disclosed in CN120300206A is an aqueous copper-ammonia complex electrolyte, which has a higher... c p This will weaken the temperature drop response corresponding to a unit of heat absorption, resulting in limited cooling range and response speed at the cold end.

[0012] (3) Patent document CN120300206A discloses a thermal battery electrolyte and its application in thermoelectric conversion. If it is used in an EPC refrigeration device, the temperature gradient generated will be limited even if current is applied, and it will be difficult to make effective use of it.

[0013] Therefore, specific designs are needed for interfacial heat absorption, low specific heat capacity response, Joule heating / polarization heat suppression, and cold / hot end thermal management during the refrigeration process. This invention constructs a water-DMF binary solution to synergistically amplify the thermoelectric potential and reduce the system's specific heat capacity. Furthermore, it creatively discovers that using this water-DMF binary solution can increase the system's thermoelectric potential to 3.51 mV / K and the specific heat capacity from 4.0 J·g⁻¹. -1 K -1 Reduced to 3.68 J·g -1 K -1 Furthermore, the cooling capacity is further enhanced by utilizing the vaporization of NH3 in the solution for refrigeration, with an input of only 0.01 W / cm². 2 It can achieve direct cooling at 1.19 K with a low power density, and its peak COP can reach 14.4, which is an unexpected technological advantage. It provides a new, efficient, energy-saving and practically valuable solution to the heat dissipation problem of electronic components, and overcomes the technical difficulties in applying electrolytes in the field of electrochemical Peltier cooling as described in CN120300206A.

[0014] As a preferred technical solution, the metal-auxiliary ligand complex ion formed by the transition metal salt and the auxiliary ligand in the solution is [Cu(NH3)2]. + and [Cu(NH3)4] 2+ The concentration of the metal-auxiliary ligand complex ion is 0.2–0.4 mol / L.

[0015] A second objective of this invention is to provide an electrochemical Peltier cooling device, comprising a reactor, a radiator, and a cooler. The reactor includes a reaction chamber, a cold-end current collector, a cold-end electrode, a hot-end current collector, a hot-end electrode, and a porous membrane. The porous membrane is located inside the reaction chamber and divides the reaction chamber into a cold-end region and a hot-end region. The cold-end electrode and the hot-end electrode are located at opposite ends of the reaction chamber. The cold-end current collector is located outside the cold-end electrode, and the hot-end current collector is located outside the hot-end electrode. Both the cold-end region and the hot-end region are filled with a copper-ammonia complex ion binary solution as described in any of the preceding claims. The radiator is connected to the cold end and hot end of the reaction chamber through a connecting pipe to form a hot end circulation path, which is used to introduce the copper ammonia complex ion binary solution located in the hot end area into the radiator and flow to the cold end area. The cooler is connected to the cold end and hot end of the reaction chamber through connecting pipes to form a cooling circulation path, which is used to introduce the copper ammonia complex ion binary solution located in the cold end area into the cooler and flow to the hot end area. The cooler is in contact with the object to be cooled.

[0016] The device described in this invention adopts a single-reactor structure, integrating the cold-end electrode, hot-end electrode, reaction chamber, and porous membrane into the same reactor. It further includes a lower cooler, an upper heat sink, and connecting pipelines, allowing the cold-end electrolyte (i.e., a copper-ammonia complex ion binary solution) to exchange heat with the chip, power device, and other objects awaiting cooling via the lower cooler. Meanwhile, the hot-end electrolyte dissipates heat through the upper heat sink, thus forming a continuous thermal management path of cold-end heat absorption, local hot spot cooling, and hot-end heat dissipation. This integrated design of the reactor, cooler, heat sink, and circulation path makes it more suitable for low-energy active cooling of local hot spots in electronic devices.

[0017] As a preferred technical solution, both the cold-end current collector and the hot-end current collector are made of graphite plates, and both the cold-end electrode and the hot-end electrode are made of carbon felt.

[0018] As a preferred technical solution, the porous membrane is made of polyurethane cotton.

[0019] As a preferred technical solution, the cold end electrode and the cold end current collector, and the hot end electrode and the hot end current collector are both sealed with thermosetting adhesive.

[0020] As a preferred technical solution, a circulation pump is provided on the connecting pipes of the hot end circulation path and the cold end circulation path.

[0021] As a preferred technical solution, fluid openings are provided on both the cold end current collector and the hot end current collector, and each fluid opening is connected to a corresponding connecting pipe, and a sealing plug is provided at each opening.

[0022] As a preferred technical solution, the radiator is provided with a hot liquid inlet and a hot liquid outlet at both ends, and the cooler is provided with a cold liquid inlet and a cold liquid outlet at both ends.

[0023] As a preferred technical solution, the input voltage of the device is 0~1V.

[0024] The advantages and beneficial effects of this invention compared to the prior art are: This invention proposes a novel refrigeration device based on the electrochemical Peltier effect of the copper-ammonia complex reaction couple, and establishes a matching scheme for material composition, device structure, and operating parameters around the EPC refrigeration process. Through the integrated design of the reactor, cooler, and radiator, synergistic optimization of cold-end heat absorption, hot-end heat dissipation, and local hot spot cooling is achieved. Regarding the electrolyte design, by introducing DMF to construct a water-DMF binary solution, the solvation environment of the copper-ammonia complex ions can be controlled, enhancing the solvation structural difference between the oxidized and reduced states of the complex ions, thereby amplifying the effective reaction entropy change and increasing the system's thermoelectric potential to 3.51 mV / K. Furthermore, the specific heat capacity of the system can be increased from 4.0 J·g⁻¹. -1 K-1 Reduced to 3.68 J·g -1 K -1 This enhances the temperature drop response corresponding to a unit of heat absorption. Simultaneously, utilizing the vaporization refrigeration of NH3 in the solution further improves the cooling capacity, requiring only an input of 0.01 W / cm². 2 Direct cooling at 1.19 K can be achieved with a low power density, and its peak COP can reach 14.4. This provides a new, efficient, energy-saving, and practically valuable approach to solving the heat dissipation problem of electronic components. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings: Figure 1 This is a schematic diagram of an electrochemical Peltier refrigeration device provided in an embodiment of the present invention.

[0026] Figure 2 The graph shows the change of thermoelectric potential of the electrolyte solution prepared in each embodiment and comparative example as a function of temperature.

[0027] Figure 3 The graphs show the response current and output power density of the electrochemical Peltier refrigeration devices constructed using the various embodiments at different voltages. Different embodiments correspond to different applied voltages.

[0028] Figure 4 The diagram shows the temperature at both the hot and cold ends of the electrochemical Peltier refrigeration device constructed in Examples 1-6 under different voltages. Different examples correspond to different applied voltages.

[0029] Figure 5 This is a comparison chart showing the cooling effect of the electrochemical Peltier cooling devices constructed using the various embodiments and comparative examples at different voltages. From left to right, the groups are: Example 1 + Comparative Example 1, Example 2 + Comparative Example 2, Example 3 + Comparative Example 3, Example 4 + Comparative Example 4, Example 5 + Comparative Example 5, and Example 6 + Comparative Example 6. The left side of each group is the embodiment, and the right side is the comparative example.

[0030] Figure 6 The figure shows the coefficient of performance (COP) curves of the electrochemical Peltier refrigeration devices constructed using the various embodiments and comparative examples at different voltages.

[0031] The labels and names of the components in the attached diagram are as follows: 1-Cold end current collector, 2-Cold end electrode, 3-Reaction chamber, 4-Porous diaphragm, 5-Hot end electrode, 6-Hot end current collector, 7-Cold liquid inlet, 8-Cold liquid outlet, 9-Hot liquid inlet, 10-Hot liquid outlet; 11-Circulation pump; 12-Radiator, 13-Cooler; 14-Connecting pipeline; 15-Sealing plug. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0033] Throughout this specification, references to "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in connection with that embodiment or example is included in at least one embodiment of the invention. Therefore, the phrases "an embodiment," "an example," "an example," or "an example" appearing in various places throughout the specification do not necessarily refer to the same embodiment or example. Furthermore, specific features, structures, or characteristics can be combined in one or more embodiments or examples in any suitable combination and / or sub-combination. Moreover, those skilled in the art will understand that the illustrations provided herein are for illustrative purposes and are not necessarily drawn to scale. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0034] In the description of this invention, the terms "front", "rear", "left", "right", "up", "down", "vertical", "horizontal", "high", "low", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this invention.

[0035] An electrochemical Peltier cooling device includes a reactor, a radiator 12, and a cooler 13. The radiator 12 is located at the upper end of the reactor and is used to remove the exothermic reaction of the hot end electrode and the heat generated during the operation of the device. The cooler 13 is located at the lower end of the reactor and is used to contact the chip, power device, or other objects to be cooled, and to receive the endothermic cooling effect generated by the cold end electrode.

[0036] The reactor includes a cold-end current collector 1, a cold-end electrode 2, a reaction chamber 3, a porous membrane 4, a hot-end electrode 5, and a hot-end current collector 6.

[0037] The reaction chamber 3 is a hollow, fully enclosed structure, and its shape can be designed as cylindrical, polygonal, etc., according to actual needs. The porous membrane 4 is located inside the reaction chamber 3 and divides it into a cold-end region and a hot-end region, separating the cold and hot end areas and reducing heat reflux. The cold-end electrode 2 and the hot-end electrode 5 are located at opposite ends of the reaction chamber, respectively. The cold-end current collector 1 is fixedly disposed on the outside of the cold-end electrode 2, and the hot-end current collector 6 is fixedly disposed on the outside of the hot-end electrode 5, for electron conduction and electrode fixation. Fluid openings are formed on the side walls of the cold-end current collector 1, the hot-end current collector 6, the cold-end electrode 2, the hot-end electrode 5, and the reaction chamber 3, creating channels for fluid entry and exit at the cold and hot ends. Figure 1 As shown, two fluid openings (not shown in the figure) are respectively opened on the cold end current collector 1 and the hot end current collector 6, which are connected to the fluid openings on the side wall of the reaction chamber 3 for injecting or discharging the copper ammonia complex ion binary solution. The copper ammonia complex ion binary solution fills the cavity through the fluid openings to form a stable electrochemical reaction interface.

[0038] The radiator 12 is connected to the cold end and hot end of the reaction chamber 3 via a connecting pipe 14 to form a hot end circulation path, such as... Figure 1 As shown, a copper-ammonia complex binary solution located in the hot end region is introduced into the radiator 12 and flows to the cold end region. The connecting pipe 14 is also connected to the corresponding flow opening. The cooler 13 is connected to the cold end region and the hot end region of the reaction chamber 3 through the connecting pipe 14 to form a cooling circulation path. The cooler 13 is used to introduce the copper-ammonia complex binary solution located in the cold end region into the cooler 13 and flow to the hot end region. The connecting pipe 14 is also connected to the corresponding flow opening. The cooler 13 is in contact with the object to be cooled. Each fluid opening is equipped with a sealing plug 15. If a rubber plug is used, it is sealed after the liquid is injected to prevent electrolyte leakage and ammonia volatilization loss.

[0039] Furthermore, in this embodiment, the cold-end current collector 1 and the hot-end current collector 6 have the same structure and material, both being graphite plates. The cold-end electrode 2 and the hot-end electrode 5 also have the same structure and material, both being carbon felt. The porous diaphragm 4 is made of polyurethane cotton. The cold-end electrode 2 and the cold-end current collector 1, and the hot-end electrode 5 and the hot-end current collector 6 are sealed with thermosetting adhesive. A circulation pump 11 is provided on the connecting pipes 14 of the hot-end circulation path and the cold-end circulation path to drive the solution to circulate between the reactor, the cooler 13, and the radiator 12, so that the heat absorption generated at the cold end and the heat release generated at the hot end can exchange heat with the object to be cooled and the external environment, respectively. A hot liquid inlet 9 and a hot liquid outlet 10 are respectively provided at both ends of the radiator 12, and a cold liquid inlet 7 and a cold liquid outlet 8 are respectively provided at both ends of the cooler 13.

[0040] A constant voltage of 0–1 V is input across the cold-end electrode 2 and the hot-end electrode 5 of the electrochemical Peltier refrigeration device. Under the action of the applied voltage, an endothermic reaction occurs at the interface of the cold-end electrode 2, and an exothermic reaction occurs at the interface of the hot-end electrode 5, thereby realizing electrochemical Peltier refrigeration.

[0041] The copper-ammonia complex binary solution in this embodiment consists of transition metal salts CuCl and CuCl2, an auxiliary ligand NH3, and the organic solvent DMF and deionized water. The solution also includes a metal-auxiliary ligand complex ion [Cu(NH3)2] formed by the transition metal salt and the auxiliary ligand. + and [Cu(NH3)4] 2+ The solution was prepared by mixing NH3, CuCl, and CuCl2 with DMF and deionized water, wherein the concentrations of CuCl, CuCl2, NH3, and DMF were 0.5–3 mol / L. The metal-auxiliary ligand complex ion in the solution is [Cu(NH3)2]. + and [Cu(NH3)4] 2+ The concentration is 0.2–0.4 mol / L.

[0042] The reaction principle of the copper-ammonia complex binary solution in this embodiment is as follows: An external voltage drives a thermoelectric ion couple to undergo redox reactions at both electrodes. Since [Cu(NH3)2]... + / [Cu(NH3)4] 2+ A partial molar entropy difference (ΔS) exists between the anode and cathode, causing endothermic and exothermic phenomena at the anode and cathode interfaces, respectively. This establishes a stable and controllable temperature difference, and effective cooling is achieved by utilizing the endothermic reaction of the electrolyte at the low-temperature end. During this process, the dynamic release / absorption of NH3 and [Cu(NH3)2]... + / [Cu(NH3)4] 2+The redox transformation of the reaction couple occurs under potential-driven conditions. Due to the participation of NH3, the number of particles increases before and after the reaction, the disorder of the system increases, and the entropy change of the solvation structure of the system can reach 232.0 J / (mol·K), corresponding to an intrinsic thermoelectric potential of 2.4 mV / K, which is significantly higher than that of traditional thermoelectric ion couples (generally lower than 2 mV / K). Furthermore, in this embodiment, a water-DMF binary solution is constructed in an aqueous copper-ammonia complex electrolyte. As a polar organic co-solvent, DMF can not only reduce the average specific heat capacity of the electrolyte and enhance the temperature drop response corresponding to a unit heat absorption, but also regulate the solvation environment of the copper-ammonia complex ions, changing the difference in solvation structure around the oxidized and reduced complex ions, thereby further amplifying the effective reaction entropy change and increasing the thermoelectric potential coefficient of the system. Based on the high intrinsic thermoelectric potential of the copper-ammonia complex reaction couple itself, and the synergistic regulatory effect of DMF on the solvation structure and specific heat capacity, this binary solution can lay the foundation for enhanced COP and rapid cold-end temperature drop in EPC devices. In addition, NH3 in the electrolyte has a high latent heat of vaporization and a low boiling point, with a latent heat of vaporization of about 23.37 kJ / mol at the boiling point. The free NH3 generated in the reaction can vaporize and absorb heat at the cold end, further improving the cooling capacity of the system.

[0043] The preparation method of the above-mentioned electrochemical Peltier refrigeration device of the present invention includes the following steps: (1) A polyurethane porous membrane 4 is filled in the center of the reaction chamber, and carbon felt electrodes and current collectors are attached to both ends of the reaction chamber 3 in sequence and sealed with thermosetting adhesive. (2) Inject water-DMF binary solution (i.e., copper ammonia complex ion binary solution) into reaction chamber 3 and seal the fluid opening with a rubber stopper; (3) Use the circulating pump 11 to drive the cold end solution into the cooler 13 and into the hot end; use the circulating pump 11 to drive the hot end solution through the radiator 12 and into the cold end; (4) The cold end region of the reactor is connected to the lower cooler 13 through the connecting pipe 14, and the cold end electrolyte is driven to flow through the lower cooler through the circulating pump 11 so that it can exchange heat with the object to be cooled. The hot end region of the reactor is connected to the upper heat sink 12 via the connecting pipe 14, and the hot end electrolyte is driven to flow through the upper heat sink 12 via the circulating pump 11, so that it releases heat to the external environment. (4) By applying a constant voltage to both ends of the reactor, an electrochemical Peltier refrigeration device is obtained.

[0044] The technical solution of the present invention will be further described in detail below with reference to the embodiments: The present invention provides 6 sets of examples (Examples 1 to 6) and 6 sets of comparative examples (Comparative Examples 1 to 6) to verify the effectiveness of the method of the present invention in preparing electrochemical Peltier refrigeration devices.

[0045] All embodiments and comparative examples are in accordance with Figure 1 The electrochemical Peltier cooling device shown was prepared. The device consists of a reactor, a lower cooler, an upper radiator, and a water-DMF binary solution. The reaction chamber is hollow, with a volume of 1 mL and dimensions of 1 × 1 × 1 cm. 3 The center of the reaction chamber is filled with a porous polyurethane membrane, measuring 1×1×0.3 cm. 3 The density is 35 ppi. The effective reaction area of ​​the electrode is 1 cm². 2 The size of the current collector is 0.5 × 1 × 1 cm. 3 The cold-end and hot-end current collectors are made of graphite plates, while the cold-end and hot-end electrodes are made of carbon felt. A water-DMF binary solution is injected into the reaction chamber through a fluid opening and sealed with a rubber stopper to prevent leakage. Finally, an external power supply is connected to the cold-end and hot-end current collectors, and a driving voltage is applied, thus completing the preparation of the electrochemical Peltier cooling device. During operation, an endothermic reaction occurs at the cold-end electrode interface and acts on the object to be cooled through the lower cooler, while the heat generated at the hot-end electrode interface is dissipated through the upper radiator, thereby achieving localized active cooling.

[0046] In each embodiment, the water-DMF binary solution was prepared according to the final concentration. Specifically, according to the ratio of CuCl concentration of 0.2 mol / L, CuCl2 concentration of 0.2 mol / L, NH3 concentration of 2 mol / L, and DMF concentration of 2 mol / L, the corresponding amounts of CuCl, CuCl2, ammonia, DMF, and deionized water were added respectively. After mixing, the solution was stirred with a magnetic stirrer until the solute was completely dissolved, yielding a solution containing [Cu(NH3)2]. + and [Cu(NH3)4] 2+ A water-DMF binary solution. The volume fraction of DMF in the final solution is approximately 16%. The differences between the various embodiments lie in the applied voltage, which are 0.1V, 0.2V, 0.4V, 0.6V, 0.8V, and 1.0V, respectively.

[0047] Each comparative solution was prepared according to the final concentration. Specifically, to achieve a final solution with CuCl concentration of 0.2 mol / L, CuCl2 concentration of 0.2 mol / L, and NH3 concentration of 2 mol / L, appropriate amounts of CuCl, CuCl2, ammonia, and deionized water were added, respectively. The mixture was then stirred with a magnetic stirrer until the solute was completely dissolved, yielding a solution containing [Cu(NH3)2]. + and [Cu(NH3)4] 2+The aqueous copper-ammonia complex solution. The difference between the various comparative examples lies in the applied voltage, which is 0.1V, 0.2V, 0.4V, 0.6V, 0.8V, and 1.0V respectively.

[0048] Performance testing: 1. The thermoelectric potential of the electrolyte solutions prepared in Examples 1-6 and Comparative Examples 1-6 was tested as a function of temperature. The results are as follows: Figure 2 As shown, Examples 1-6 α It is 3.51 mV / K; Comparative Examples 1~6 α It is 2.18 mV / K.

[0049] The specific heat capacity was calculated based on the electrolyte ratios of Examples 1-6 and Comparative Examples 1-6. The specific heat capacity of Examples 1-6... c p It is 3.68 J·g -1 K -1 Comparative Examples 1-6 c p 4.0 J·g -1 K -1 .

[0050] 2. The refrigeration performance of the electrochemical Peltier refrigeration devices prepared in Examples 1-6 and Comparative Examples 1-6 was tested, and the results are as follows. See Figure 5 , 6 As shown in the image. Figure 4 The diagram shows the temperatures at the hot and cold ends of the electrochemical Peltier refrigeration device constructed in the embodiment at different voltages.

[0051] Example 1: Applied voltage 0.1 V; cold junction temperature drop 0.18 K; COP is 14.43.

[0052] Example 2: Applied voltage 0.2 V; cold junction temperature drop 0.54 K; COP 4.73.

[0053] Example 3: Applied voltage 0.4 V; cold junction temperature drop 0.61 K; COP 2.11.

[0054] Example 4: Applied voltage 0.6 V; cold junction temperature drop 0.72 K; COP 1.24.

[0055] Example 5: Applied voltage 0.8 V; cold junction temperature drop 0.94 K; COP 0.81.

[0056] Example 6: Applied voltage 1.0 V; cold junction temperature drop 1.19 K; COP 0.55.

[0057] Comparative Example 1: Applied voltage 0.1 V; cold junction temperature drop 0.07 K; COP 8.72.

[0058] Comparative Example 2: Applied voltage 0.2 V; cold junction temperature drop 0.10 K; COP 2.73.

[0059] Comparative Example 3: Applied voltage 0.4 V; cold junction temperature drop 0.17 K; COP 1.11.

[0060] Comparative Example 4: Applied voltage 0.6 V; cold junction temperature drop 0.26 K; COP 0.58.

[0061] Comparative Example 5: Applied voltage 0.8 V; cold junction temperature drop 0.3 K; COP 0.31.

[0062] Comparative Example 6: Applied voltage 1.0 V; cold junction temperature drop 0.4 K; COP 0.15.

[0063] 3. The response current and output power density curves of the electrochemical Peltier refrigeration devices constructed in each embodiment under different voltages are shown below. Figure 3 As shown.

[0064] By comparing the thermoelectric potential, specific heat capacity, and refrigeration performance of Examples 1-6 with those of Comparative Examples 1-6, Figure 4-6 The test results clearly show that the optimization of the solution composition in this invention significantly improves the performance of the electrochemical Peltier refrigeration device. Examples 1-6 α The direct temperature drop and COP are significantly higher than those of Comparative Examples 1-6, indicating that the method of the present invention can significantly improve the refrigeration performance of the electrochemical Peltier refrigeration device. Example 6 Input: 0.01 W / cm² 2 Direct cooling at 1.19 K can be achieved with low power density. Figure 5 Furthermore, Example 1 achieves a coefficient of performance (COP) of 14.4. Figure 6 This demonstrates the advantages of this invention in high-efficiency refrigeration.

[0065] The above specific embodiments further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A copper-ammonia complex ion binary solution for electrochemical Peltier cooling, characterized in that, The solution comprises a transition metal salt, an auxiliary ligand, an organic solvent, and deionized water; The transition metal salt includes CuCl and CuCl2, the auxiliary ligand is NH3, and the organic solvent is N,N-dimethylformamide; The concentration of CuCl in the solution is 0.1–0.2 mol / L, the concentration of CuCl2 is 0.1–0.2 mol / L, the concentration of NH3 is 1–4 mol / L, and the concentration of N,N-dimethylformamide is 0.5–3 mol / L.

2. A copper-ammonia complex ion binary solution for electrochemical Peltier cooling according to claim 1, characterized in that, The metal-auxiliary ligand complex ion formed by the transition metal salt and the auxiliary ligand in the solution is [Cu(NH3)2]. + and [Cu(NH3)4] 2+ The concentration of the metal-auxiliary ligand complex ion is 0.2–0.4 mol / L.

3. An electrochemical Peltier refrigeration device, characterized in that, The device includes a reactor, a radiator, and a cooler. The reactor includes a reaction chamber, a cold-end current collector, a cold-end electrode, a hot-end current collector, a hot-end electrode, and a porous membrane. The porous membrane is located inside the reaction chamber and divides the reaction chamber into a cold-end region and a hot-end region. The cold-end electrode and the hot-end electrode are located at opposite ends of the reaction chamber. The cold-end current collector is located outside the cold-end electrode, and the hot-end current collector is located outside the hot-end electrode. Both the cold-end region and the hot-end region are filled with a copper-ammonia complex ion binary solution as described in any one of claims 1 to 2. The radiator is connected to the cold end and hot end of the reaction chamber through a connecting pipe to form a hot end circulation path, which is used to introduce the copper ammonia complex ion binary solution located in the hot end area into the radiator and flow to the cold end area. The cooler is connected to the cold end and hot end of the reaction chamber through connecting pipes to form a cooling circulation path, which is used to introduce the copper ammonia complex ion binary solution located in the cold end area into the cooler and flow to the hot end area. The cooler is in contact with the object to be cooled.

4. The electrochemical Peltier refrigeration device according to claim 3, characterized in that, Both the cold-end current collector and the hot-end current collector are made of graphite plates, and both the cold-end electrode and the hot-end electrode are made of carbon felt.

5. An electrochemical Peltier refrigeration device according to claim 3, characterized in that, The porous diaphragm is made of polyurethane cotton.

6. The electrochemical Peltier refrigeration device according to claim 3, characterized in that, The cold end electrode and the cold end current collector, as well as the hot end electrode and the hot end current collector, are all sealed with thermosetting adhesive.

7. An electrochemical Peltier refrigeration device according to claim 3, characterized in that, Both the hot-end circulation path and the cold-end circulation path are equipped with circulation pumps on their connecting pipes.

8. An electrochemical Peltier refrigeration device according to claim 3, characterized in that, Fluid openings are provided on both the cold end current collector and the hot end current collector, and each fluid opening is connected to a corresponding connecting pipe. Each opening is provided with a sealing plug.

9. An electrochemical Peltier refrigeration device according to claim 3, characterized in that, The radiator has a hot liquid inlet and a hot liquid outlet at both ends, and the cooler has a cold liquid inlet and a cold liquid outlet at both ends.

10. An electrochemical Peltier refrigeration device according to claim 3, characterized in that, The input voltage of the device is 0~1V.

Images