Thermal management system and method, and stacked electrochemical reactor

Abstract

The invention relates to the technical field of thermal management, and discloses a thermal management system and method and a stacked electrochemical reactor, the reactor comprises a plurality of electrochemical reaction units, each unit comprises a bipolar plate pair and an electrochemical reaction medium, the two sides of each bipolar plate are provided with tabs, and the tabs are connected with the electrochemical reaction medium. The width of the tabs is at least a preset proportion of the short side length of the bipolar plate, and the thermal management system comprises two switch device combinations which are respectively positioned on two sides of the electrochemical reaction units and are connected with the tabs on the corresponding sides; the control device is used for controlling the combined action of the two switch devices to enable the bipolar plates to be connected in series or in parallel when the reactor is in a heat preservation stage, and inputting a first preset current to the reactor, so that effective heat preservation of the electrochemical reactor is realized; compared with electrolyte circulation or external heat exchange methods, the method has higher energy efficiency and uniformity of temperature management of the electrochemical reactor.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of thermal management, in particular to a thermal management system and method, and a stacked electrochemical reactor. BACKGROUND

[0002] With the gradual advent of the new energy power era, the following trends / demands arise: 1) electricity prices are steadily declining; 2) electricity generated in the new energy power grid needs to be absorbed; 3) there is a higher demand for low-carbon chemical technology. Therefore, electrochemical industry technology, as a promising development direction of chemical industry, is gradually emerging. The core of electrochemical industry technology is an electrochemical reactor that couples electrical energy and chemical energy. It can achieve chemical conversion through electrical energy input, such as water electrolysis to produce hydrogen, and it can also achieve electrical energy output through chemical conversion, such as hydrogen fuel cells.

[0003] Among these electrochemical reactors, a stacked structure can maximize the utilization efficiency of the reactor material, and it is one of the most widely used electrochemical reactor structures. A stacked electrochemical reactor generally includes a bipolar plate for electrical conduction and an electrochemical reaction medium between the bipolar plates.

[0004] Electrochemical reactions usually need to be carried out at a certain temperature, for example, the reaction temperature of alkaline water electrolysis is 80°C, which is to ensure the electrical conductivity of the electrolyte. In addition, the storage temperature of the electrochemical reactor cannot be lower than a certain value. For example, in a new energy power station, the ambient temperature is usually lower than the normal operating temperature of the electrochemical reactor (such as a water electrolysis cell), at which time the heat preservation of the electrochemical reactor becomes extremely important. Too low a temperature causes the electrolyte to freeze, and the ice crystals produced can damage the ion exchange membrane therein. The above operations such as heating and heat preservation of the electrochemical reactor can be regarded as thermal management of the electrochemical reactor, which plays a crucial role in the operation of the electrochemical reactor.

[0005] Currently, there are mainly two methods to achieve thermal management of the electrochemical reactor. One is to achieve heating or heat preservation of the electrochemical reactor through electrolyte circulation, which relies on external electrolyte heating devices and circulation devices, and has low energy utilization efficiency and cannot guarantee uniform thermal management of the electrochemical reactor. The second method is to use external infrared heating devices, or heating blankets, phase change latent heat materials, etc. to heat the electrochemical reactor from the outside to protect the electrochemical reactor in a low temperature environment. The energy utilization efficiency of this method is also low, and the effect of thermal management on a large-scale electrochemical reactor (size greater than 0.5m 3 ), SUMMARY

[0006] The present application aims to provide a thermal management system and method, and a stacked electrochemical reactor, which can realize effective heat preservation of the electrochemical reactor, and has higher energy efficiency and uniformity of the electrochemical reactor temperature management compared to the method of electrolyte circulation or external heat exchange.

[0007] To achieve the above-mentioned purpose, one aspect of the present application provides a thermal management system suitable for a stacked electrochemical reactor, the stacked electrochemical reactor comprising a plurality of electrochemical reaction units, each of the electrochemical reaction units comprising a pair of bipolar plates and an electrochemical reaction medium, wherein both sides of each bipolar plate are configured with tabs, the width of the tabs being at least a preset proportion of the length of the short side of the bipolar plate, the thermal management system comprising: two switch device combinations respectively located on both sides of the plurality of electrochemical reaction units and connected with the tabs on the corresponding side; and a control device for, when the stacked electrochemical reactor is in a heat preservation stage, controlling the two switch device combinations to connect the bipolar plates in series or in parallel, and inputting a first preset current to the stacked electrochemical reactor.

[0008] Preferably, when the control device is used to control the two switch device combinations to connect the bipolar plates in parallel, the control device is further used to, when the stacked electrochemical reactor is in a pre-reaction temperature rising stage, control the two switch device combinations to connect the bipolar plates in series, and input a second preset current to the stacked electrochemical reactor, wherein the second preset current is equal to or greater than the first preset current.

[0009] Preferably, when the control device is used to control the two switch device combinations to connect the bipolar plates in series or in parallel, the control device is further used to, when the stacked electrochemical reactor is in a pre-reaction temperature rising stage, control the two switch device combinations to connect the bipolar plates in the same way as in the heat preservation stage, and input a second preset current to the stacked electrochemical reactor, wherein the second preset current is greater than the first preset current.

[0010] Preferably, the switch device combination comprises: a plurality of control switch pairs, the control switches in the control switch pairs being connected in series with the corresponding bipolar plates in the pair of bipolar plates via the corresponding tabs; and a plurality of connection switches, the connection switches connecting two adjacent control switches.

[0011] Preferably, the switch device combination comprises: a plurality of control switches distributed in a two-part management structure.

[0012] Preferably, the thermal management system further comprises a voltage patrol device for monitoring the electromotive force between any two bipolar plates when the stacked electrochemical reactor is in the reaction stage.

[0013] By the above technical solution, the present application sets wider tabs on both sides of the bipolar plate and sets two switch devices in the external circuit, when the stacked electrochemical reactor is in the heat preservation stage, the bipolar plates are connected in series or parallel by controlling the combined action of the two switch devices, and a first preset current is input to the stacked electrochemical reactor, thereby realizing effective heat preservation of the electrochemical reactor, and compared with the electrolyte circulation or external heat exchange method, the present application has higher energy efficiency and uniformity of electrochemical reactor temperature management.

[0014] The second aspect of the present application provides a thermal management method, characterized by being applicable to a stacked electrochemical reactor, the stacked electrochemical reactor comprising a plurality of electrochemical reaction units, each of the electrochemical reaction units comprising a bipolar plate pair and an electrochemical reaction medium, wherein both sides of each bipolar plate are configured with tabs for connecting an external circuit, the width of the tab is at least a preset proportion of the length of the short side of the bipolar plate, the thermal management method comprising: judging the stage of the stacked electrochemical reactor; and when the stacked electrochemical reactor is in the heat preservation stage, connecting the bipolar plates in series or parallel by controlling the combined action of two switch devices, and inputting a first preset current to the stacked electrochemical reactor, wherein the two switch devices are respectively located on both sides of the plurality of electrochemical reaction units and connected with the tabs on the corresponding side.

[0015] Preferably, in the case of connecting the bipolar plates in parallel by controlling the combined action of the two switch devices, the control method further comprises: when the stacked electrochemical reactor is in the pre-reaction heating stage, connecting the bipolar plates in series by controlling the combined action of the two switch devices, and inputting a second preset current to the stacked electrochemical reactor, wherein the second preset current is equal to or greater than the first preset current.

[0016] Preferably, in the case of connecting the bipolar plates in series or parallel by controlling the combined action of the two switch devices, the control method further comprises: when the stacked electrochemical reactor is in the pre-reaction heating stage, connecting the bipolar plates in the same way as in the heat preservation stage by controlling the combined action of the two switch devices, and inputting a second preset current to the stacked electrochemical reactor, wherein the second preset current is greater than the first preset current.

[0017] The specific details and benefits of the thermal management system provided by the embodiments of the present application can be referred to the description of the thermal management method above, and will not be repeated here.

[0018] One embodiment of the present application provides a stacked electrochemical reactor, which comprises the heat management system.

[0019] Other features and advantages of the present application will be illustrated in the following detailed description. BRIEF DESCRIPTION OF DRAWINGS

[0020] The accompanying drawings are included to provide a further understanding of embodiments of the application, and are incorporated in and constitute a part of this specification, illustrate embodiments of the application, and together with the description serve to explain embodiments of the application. In the drawings:

[0021] Figure 1a is a structural schematic diagram of a stacked electrochemical reactor provided by one embodiment of the present application;

[0022] Figure 1b is a schematic diagram of a normal current I working mode of a stacked electrochemical reactor provided by one embodiment of the present application;

[0023] Figure 2 is a schematic diagram of a bipolar plate connection external circuit design in a full road management mode provided by one embodiment of the present application;

[0024] Figure 3 is a schematic diagram of a touch electric design for monitoring an electromotive force of an electrochemical reaction unit provided by one embodiment of the present application;

[0025] Figure 4 is a schematic diagram of a bipolar plate connection external circuit design in a two-part management mode provided by one embodiment of the present application;

[0026] Figure 5 is a schematic diagram of a current II working mode of a stacked electrochemical reactor provided by one embodiment of the present application;

[0027] Figure 6 is a schematic diagram of a current II working mode of a stacked electrochemical reactor provided by one embodiment of the present application;

[0028] Figure 7 a is a structural schematic diagram of a stacked electrochemical reaction unit provided by one embodiment of the present application; and

[0029] Figure 7 b-7f are respectively results of temperature rise caused by heat conduction of bipolar plate Joule heat in a stacked electrochemical reaction unit through different times simulated by finite element simulation provided by one embodiment of the present application. DETAILED DESCRIPTION

[0030] The specific embodiments of the present application are described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative and explanatory in nature and are not intended to limit the application.

[0031] In the process of normal operation of the stacked electrochemical reactor (i.e. the stacked electrochemical reactor is in the reaction stage), the current flows from one end to the other end of the stacked structure, and a voltage drop is generated in each electrochemical reaction unit, which drives the conversion between electrical energy and chemical energy. This operating mode is referred to as normal current I, as shown in Figure 1b . The inventors have found that in the direction of Figure 1b current, in the working mode of normal current I, the current flows from the current inlet A, and the potential in the bipolar plate is relatively uniform, and the current II is smaller than the normal current I. Generally, the normal current I mode is the main working mode of the stacked electrochemical reactor, and the current in the entire reactor is mainly perpendicular to the bipolar plate, which is conducted through the electron-conducting bipolar plate and the ion-conducting electrochemical reaction medium, thereby realizing the mutual conversion between electrical energy and chemical energy in the electrochemical reaction medium. In this process, the generated current generates Joule heat Q on the bipolar plate, and the thermal power value is P = I 2 R. Wherein I is the surface current density on the bipolar plate, and R is the surface resistance of the bipolar plate. In the normal current I mode, the current and voltage of the electrochemical reactor follow the I-V characteristic curve of the electrocatalytic reaction. For an electrolytic cell, the current I of the electrolytic cell must be greater than the electrochemical equilibrium electromotive force E to significantly increase, and at this time the electrochemical reaction occurs in the electrolytic cell, so the Joule heat Q at this time cannot be used to realize the heat management of the electrolytic cell when it is not working.

[0032] The present application mainly realizes the heat preservation or heating process of the working mode of current II (as shown in Figure 5 or Figure 6 , etc.) through the circuit connection topology (as shown in Figure 2 or Figure 4 ), thereby realizing the heat management of the stacked electrochemical reactor. Specifically, the current flows from the current inlet A, and the potential in the bipolar plate presents a gradient distribution along the long side direction, and the current II is the main current in the stacked electrochemical reactor, and there is almost no or no normal current. In this operating mode, the Joule heat Q generated in the bipolar plate of the electrochemical reactor is used for heat preservation or heating of the reactor.

[0033] An embodiment of the present application provides a heat management system, which is applicable to a stacked electrochemical reactor 1 as shown in Figure 1a , and the heat management system can include two switch device combinations 10 and a control device (not shown), as shown in Figure 2 .

[0034] Depending on the choice of bipolar plate (3) and electrochemical reaction medium (6), the stacked electrochemical reactor 1 can include, but is not limited to, water electrolyzer for splitting water into hydrogen and oxygen, hydrogen fuel cell for converting hydrogen and oxygen into water and electricity, electrolyzer for converting carbon dioxide into high value-added chemicals, etc.

[0035] The stacked electrochemical reactor 1 is first introduced as shown in Figure 1a or Figure 1b .

[0036] The stacked electrochemical reactor 1 includes a plurality of electrochemical reaction units 2, wherein each electrochemical reaction unit 2 includes a bipolar plate pair (including two bipolar plates 3) and an electrochemical reaction medium 4. Each bipolar plate has two sides configured with tabs 31 for connecting external circuit, and the width of the tabs 31 is at least a preset proportion (e.g., 2 / 3) of the short side length of the bipolar plate 3, as shown in Figure 1a or Figure 1b . In addition, Figure 1a the circulation inlet and outlet of electrolyte / reaction liquid 32-35 are also shown. In different designs of electrochemical reactors, the inlet can be on the same side or on both sides (such as the reactor structure of Hydrogenics company).

[0037] The stacked electrochemical reactor includes at least two electrochemical reaction units. Each electrochemical reaction unit is an independent basic structure that can realize the conversion of electrical energy to chemical energy or the conversion of chemical energy to electrical energy. The entire stacked electrochemical reactor is composed of alternating bipolar plates and electrochemical reaction media, and the interior of the adjacent two bipolar plates constitutes the above-mentioned electrolytic unit.

[0038] The bipolar plate is made of titanium, stainless steel, nickel alloy or carbon material, or a combination of several materials. The surface of the bipolar plate has or does not have a coating, which aims to enhance the stability of the bipolar plate under electrochemical reaction conditions. The electrochemical reaction medium includes, but not necessarily all of the following components: porous transport layer, electrolyte, and electrocatalyst. The porous transport layer is a porous material with pore diameters between nanometers and microns. The electrolyte can be an electrolyte, a gel electrolyte, and a solid electrolyte. The electrocatalyst catalyzes a specific electrochemical reaction, which can be coated on the surface of the diffusion layer, the surface of the gel electrolyte, or the surface of the solid electrolyte, or can exist in a self-supporting form.

[0039] The tabs 4 on the short sides of the bipolar plate 3 are connected to the external circuit, ensuring good circuit connection and minimizing contact resistance. The width of the tabs needs to be at least 2 / 3 of the short side length of the bipolar plate to maximize the in-plane potential gradient distribution of the bipolar plate close to the one-dimensional model. At the same time, wider tabs and corresponding larger contact area can reduce the resistance of the circuit connection.

[0040] Next, the specific content of the heat management system suitable for the stacked electrochemical reactor 1 is described.

[0041] As shown in Figure 4 , the heat management system includes two switch device combinations 10 respectively located on both sides of the plurality of electrochemical reaction units 2 and connected with the tab 31 of the corresponding side, and a control device (not shown) for connecting the bipolar plates 3 in series or in parallel by controlling the action of the two switch device combinations 10 when the stacked electrochemical reactor 1 is in the heat preservation stage, and inputting a first preset current to the stacked electrochemical reactor 1.

[0042] Since the surface resistance of the bipolar plate (metallic conduction) is much smaller than the resistance of the electrochemical reaction medium (solution, gel electrolyte, solid electrolyte conduction), the current flows from the bipolar plate surface, and this mode of operation is called surface current II. This embodiment provides an efficient internal heat preservation and heating method by changing the connection mode of the bipolar plates in the electrochemical reactor.

[0043] Two embodiments of the switch device combination are given below, of course, the present application is not limited to the following two embodiments, and reasonable variations based thereon are within the scope of the present application.

[0044] In one embodiment, as shown in Figure 2 , the switch device combination 10 includes a plurality of control switch pairs 12, the control switches (such as control switches 121, 122) in the control switch pair are connected in series with the corresponding bipolar plate 3 via the corresponding tab, and a plurality of connection switches 13, the connection switches (such as connection switch 131) connect adjacent two control switches (such as control switches 121, 122).

[0045] Specifically, the control switches (such as control switches 121-12n) in the plurality of control switch pairs 12 are connected to the corresponding tab 31 by the copper bar 11 to form a series circuit with the corresponding bipolar plate 3, as shown in the full road management structure. Figure 2 The tabs of the bipolar plates are connected with the external circuit to minimize the contact resistance and reduce the heat generation at the connection. The plurality of control switch pairs 12 are individual control switches for the bipolar plate circuit branch, and the plurality of connection switches 13 are connection switches on the main circuit. Preferably, any switch in the switch device combination is programmed and controlled by a computer to realize the freedom of external circuit connection, and when the state of the switch group is changed, the connection mode between the bipolar plates 3 will change. And the switch group covered by the switch device combination 1010 is placed in an insulating box to avoid the danger that may be caused by the electric arc generated in the process of switch action.

[0046] Accordingly, the control device (not shown) is used to control the combined operation of the two switching devices to cause the bipolar plates to be connected in series by: controlling the corresponding control switches in the plurality of control switch pairs located on both sides of the plurality of electrochemical reaction units to close at every N switches; controlling the corresponding connection switches in the plurality of connection switches located on one side of the plurality of electrochemical reaction units to close at every N+1 switches; and controlling the corresponding connection switches in the plurality of connection switches located on the other side of the plurality of electrochemical reaction units to close in a complementary manner.

[0047] by Figure 2 For example (i.e., N=0), the stacked electrochemical reactor stops operating. When it is detected that it requires heat preservation (i.e., it is in the heat preservation stage), all control switches 12 are closed. Simultaneously, on one side, connecting switches 131, 133, 135, 137… are closed intermittently, and on the other side, connecting switches 132, 134, 136, 138… are closed intermittently, thus forming a… Figure 5 The circuit shown is a series circuit. As an example, if the bipolar plate is made of 316L stainless steel, is 50.00 cm long, and 0.10 cm thick, the surface resistance is 0.1 Ω·cm according to the current connection method. 2 If 1-5 A·cm –2 If the current is such that the Joule heating power generated is P = 0.1~2.5W·cm, then the Joule heating power generated is P = 0.1~2.5W·cm. –2 Considering the rate of heat exchange between the electrochemical reactor and the external environment, adjusting the heat power can achieve the purpose of heat preservation.

[0048] by Figure 2 For example (i.e., N=1), when the stacked electrochemical reactor stops operating and it is detected that it needs to be kept warm (i.e., it is in the heat preservation stage), the control switches 121, 123, 125, 127... in control switch pair 12 can be closed on one side, and the connecting switches 131, 132, 135, 136... can be closed simultaneously; on the other side, the control switches 121, 123, 125, 127... in control switch pair 12 can be closed simultaneously, and the connecting switches 133, 134, 137, 138... can be closed, thus forming a... Figure 6 The circuit shown is a series circuit. In this case, the bipolar plates within the stacked electrochemical reactor are heated intermittently, suitable for applications where heat supply requirements are not high. Figure 6 In the connection shown, the bipolar plates 3 are partially connected in series, which allows for the regulation of the electrothermal power P in the entire stacked electrochemical reactor, thus enabling more precise thermal management.

[0049] Of course, the present invention is not limited to the two specific switch connection methods mentioned above; that is, N can also be other positive integer values.

[0050] In another embodiment, such asFigure 4 As shown, the switch assembly 10 includes a plurality of control switches (e.g., control switches 12a, 12b, 12c) distributed in a binary management structure.

[0051] Specifically, the control switch in the first-level control switch 12a is connected to the corresponding tab 31 via the copper busbar 11 to form a series circuit with the corresponding bipolar plate 3, such as... Figure 4 As shown, of course, Figure 4 The corresponding switch assembly 10 on the left side is omitted. Each bipolar plate in the stacked electrochemical reactor is controlled by an independent switch in control switch 12a (level 1, 2k switches). To the right of level 1 control switch 12a, every two branches are controlled by a control switch, forming level 2 control switches 12b (level 2, k switches). Similarly, to the right of level 2 control switches 12b, every two branches are controlled by a control switch, forming level 3 control switches 12c (level 3, k / 2 (k is even) or (k+1) / 2 (k is odd) switches), and so on until the final level 1 switch, controlling the entire circuit. Here, 2k represents the number of bipolar plates.

[0052] Accordingly, the control device (not shown) is used to connect the bipolar plates in series by controlling the combined action of the two switching devices, including: controlling the first-level control switch to close and controlling the other control switches at each level on the branch corresponding to the last bipolar plate to close on one side of the reactor; and controlling the first-level control switch to close and the second-level control switch to close on the other side of the reactor.

[0053] by Figure 4 For example, on one side, close the first-level control switch 12a and all switches in the last branch (corresponding to the last bipolar plate); on the other side, close the first-level control switch 12a and the second-level control switch 12b to form a configuration as follows: Figure 5 The series circuit shown.

[0054] The control device (not shown) is used to connect the bipolar plates in series by controlling the combined action of the two switching devices, including: for one side of the reactor, controlling the odd-numbered switch in the first-level control switch to close, controlling the second-level control switch to close, and controlling the other control switches at each level on the branch corresponding to the last bipolar plate to close; for the other side of the reactor, controlling the first-level control switch to close, and controlling the second-level control switch to close.

[0055] by Figure 4For example, on one side, close the odd-numbered switch of the first-level control switch 12a, all switches of the second-level control switch 12b, and all switches of the last branch (corresponding to the last bipolar plate); on the other side, close the odd-numbered switch of the first-level control switch 12a except for the first switch, close all switches of the second-level control switch 12b, and close all switches of the third-level control switch 12c.

[0056] The characteristic of the binary management structure is that it simplifies the structure of the main circuit in the external circuit as much as possible, minimizes the number of switching changes when the circuit connection method changes, and enhances the stability of the circuit system.

[0057] In one embodiment, the control device (not shown) for controlling the combined action of the two switching devices to connect the bipolar plates in parallel includes: controlling the plurality of control switches and the plurality of connection switches to close.

[0058] by Figure 2 For example, multiple control switch pairs 12 and multiple connection switches 13 in the switch assembly 10 on both sides are closed to form a parallel connection of all bipolar plates.

[0059] In another embodiment, the control device (not shown) is used to cause the bipolar plates to be connected in parallel by controlling the combined action of the two switching devices, including controlling the multiple control switches distributed in a binary management structure to close.

[0060] by Figure 4 For example, all control switches (level 1 control switches 12a, 12b, 12c) in the switch assembly 10 on both sides of the control are closed in a bipolar management structure to form a parallel connection of all bipolar plates.

[0061] The connection control methods for the external circuit switching devices can be divided into full-circuit management mode and two-part management mode. In full-circuit management mode, each bipolar plate corresponds to an on / off switching device, and also to a switching device connected to the main circuit line. The connection mode of the bipolar plates in the electrochemical reactor can be adjusted by closing / cutting off the corresponding switches. In two-part management mode, the bipolar plates are managed in a hierarchical manner, requiring a division into 2k, k, and k / 2 / (k+1) / 2 levels, which allows for rapid switching between several bipolar plate connection modes. The advantage of full-circuit management mode is that it provides the maximum controllability and flexibility of the bipolar plate connection mode. However, it inevitably introduces greater load fluctuations and arc voltages into the main circuit, increasing its uncertainty and the requirements for the corresponding switches. The advantage of two-part management mode is that it overcomes this uncertainty by not installing electrical switches on the main circuit. Consequently, its control flexibility decreases.

[0062] The above embodiments all involve the need for heat preservation treatment, by regulating several groups of electrical switches in the external circuit, so that the bipolar plates in the stacked electrochemical reactor are connected in series / parallel; by setting a suitable first preset current in the external circuit, so that the total Joule heat Q of the bipolar plates reaches the necessary condition for the heat preservation of the stacked electrochemical reactor: the balance of heat dissipation and heat supply. Wherein, the first preset current is in the range of 1-5 A·cm –2 The total Joule heat power P of the bipolar plate 3 is in the range of 0.1-2.5 W·cm –2

[0063] In the following two embodiments, the specific content of the thermal management system in the pre-reaction warming stage will be introduced. In this stage, more heat energy needs to be provided to achieve the warming condition.

[0064] In an embodiment, in the case where the control device is used to control the combined action of the two switch devices to connect the bipolar plates in parallel, the control device is also used to control the combined action of the two switch devices to connect the bipolar plates in series and input a second preset current to the stacked electrochemical reactor when the stacked electrochemical reactor is in the pre-reaction warming stage, wherein the second preset current is equal to or greater than the first preset current.

[0065] If the parallel connection of the bipolar plates is achieved by controlling the combined action of the switch devices in the heat preservation stage, more heat energy is needed for the overall warming before the stacked electrochemical reactor (1) starts to react (i.e. the pre-reaction warming stage), so by regulating several groups of electrical switches in the external circuit, the bipolar plates 3 in the stacked electrochemical reactor can be connected in a different way than in the heat preservation stage-serial connection, and the same or larger current as in the heat preservation stage can be input to make the total Joule heat Q of the bipolar plates 3 reach the necessary condition for the warming of the stacked electrochemical reactor: the warming of the bipolar plates 3 and the electrochemical reaction medium 4 in the reactor, and the balance of heat dissipation and heat supply of the reactor. Compared with the parallel connection circuit structure in the heat preservation stage, the resistance of the series connection circuit structure in this warming stage is larger, so the same or larger current can be used to provide more heat energy to achieve the purpose of warming.

[0066] In another embodiment, in the case where the control device is used to control the combined action of the two switch devices to connect the bipolar plates in series or parallel, the control device is also used to control the combined action of the two switch devices to connect the bipolar plates in the same way as in the heat preservation stage and input a second preset current to the stacked electrochemical reactor when the stacked electrochemical reactor is in the pre-reaction warming stage, wherein the second preset current is greater than the first preset current.

[0067] ​If the same connection method as the heat preservation stage is used during the heating stage, then more heat energy needs to be generated by adjusting the input current of the heating stage - the second preset current.

[0068] by Figure 2 For example (i.e., N=1), when the stacked electrochemical reactor is about to start operation and a temperature increase is detected (i.e., the pre-reaction temperature increase stage), switches 121, 123, 125, 127... in control switch pair 12 can be closed on one side, while connecting switches 131, 132, 135, 136... can be closed simultaneously; on the other side, switches 121, 123, 125, 127... in control switch pair 12 can be closed simultaneously, while connecting switches 133, 134, 137, 138... can be closed, thus forming... Figure 6 The circuit shown is a series circuit. As an example, if the bipolar plate is made of 316L stainless steel, is 50.00 cm long, and 0.10 cm thick, the surface resistance is 0.1 Ω·cm according to the current connection method. 2 If 5-15 A·cm –2 If the current is such that the Joule heating power P is 2.5–22.5 W·cm⁻¹, then the generated Joule heating power is P = 2.5–22.5 W·cm⁻¹. –2 Considering the electrolyte circulation rate in the electrochemical reactor, adjusting the thermal power can achieve the purpose of raising its temperature.

[0069] It should be noted that for the pre-reaction heating stage, the control method described above for the heat preservation stage can be used to control the switching device combination, thereby achieving the purpose of series / parallel connection of bipolar plates. The tab width of the bipolar plates, as well as the width and cross-sectional area of ​​the contact surface with the array, should be as large as possible. The tab width should be at least 2 / 3 of the short side of the bipolar plate to minimize heat generation at the connection point and thus prevent melting. The switching device combination for the external circuit should be kept in a sealed state as much as possible. During the external circuit connection operation, the electric arc generated by the switching device should be effectively contained within the insulation device to avoid possible combustion and explosion accidents, especially in water electrolyzers or hydrogen fuel cells, where H2 released from the environment may cause such dangers.

[0070] In one embodiment, the thermal management system further includes a voltage monitor for monitoring the electromotive force between any two bipolar plates when the stacked electrochemical reactor is in the reaction phase.

[0071] The aforementioned external circuit connection structure can also be used in the normal normal current I operating mode (i.e., the reaction stage). In this mode, the current in the stacked electrochemical reactor is injected from A and exits from B, closing the left control switch 121 and the right control switch 12n, while opening all other switches. Simultaneously, by… Figure 3 As shown, a voltage monitoring instrument 1b can also be connected to monitor the electromotive force between any two bipolar plates to obtain the performance data of the electrochemical reactor.

[0072] Specifically, the process of the Joule heat transfer in the stacked electrochemical reaction unit is given by the way of the finite element analysis theory calculation. Figure 7 As shown in FIG. a, for a typical electrochemical reaction unit 2, including a bipolar plate (upper) 3a; a bipolar plate (lower) 3b; a fluid distribution layer (upper) 4a in the electrochemical reaction medium; a porous transport layer (upper) 4b in the electrochemical reaction medium; a solid electrolyte and catalyst layer 4c in the electrochemical reaction medium; a porous transport layer (lower) 4d in the electrochemical reaction medium; a fluid distribution layer (lower) 4e in the electrochemical reaction medium. Assuming that the Joule heat power P = 20 W·cm –2 The temperature rising process in the structure unit at different times is simulated, Figure 7 b-7f is the temperature distribution from 0.3s to 1.5s, and it can be found that the temperature rises faster in the process of metal heat conduction, which proves the effectiveness of the heat management method in the present application from the side.

[0073] It should be noted that, in the normal working process of the stacked electrochemical reactor (i.e. the stacked electrochemical reactor is in the reaction stage), the current is injected from A and collected from B, and the stacked electrochemical reactor operates in the normal current I mode. Figure 2 For example, only the left control switch 121 and the right control switch 12n are closed, and all other switches are open. Thus, when switching from the reaction stage to other stages, the switches not mentioned in the control process are all in the default open state.

[0074] In summary, the present application sets a wider tab on both sides of the bipolar plate, and sets two switch devices in the external circuit. When the stacked electrochemical reactor is in the heat preservation stage, the two switch devices are combined to make the bipolar plate connected in series or parallel, and a first preset current is input to the stacked electrochemical reactor, so as to realize effective heat preservation of the electrochemical reactor. Compared with the method of electrolyte circulation or external heat exchange, it has higher energy efficiency and uniformity of electrochemical reactor temperature management.

[0075] An embodiment of the present application provides a thermal management method suitable for a stacked electrochemical reactor, the stacked electrochemical reactor comprising a plurality of electrochemical reaction units, each of the electrochemical reaction units comprising a pair of bipolar plates and an electrochemical reaction medium, wherein two sides of each of the bipolar plates are configured with tabs for connecting an external circuit, the width of the tabs being at least a preset proportion of the length of the short side of the bipolar plate, the thermal management method comprising: determining a stage in which the stacked electrochemical reactor is located; and when the stacked electrochemical reactor is in a heat preservation stage, connecting the bipolar plates in series or in parallel by controlling the combined action of two switching devices, and inputting a first preset current to the stacked electrochemical reactor, wherein the two switching devices are located on two sides of the plurality of electrochemical reaction units and connected to the tabs on the corresponding side.

[0076] Preferably, in the case of connecting the bipolar plates in parallel by controlling the combined action of the two switching devices, the control method further comprises: when the stacked electrochemical reactor is in a pre-reaction heating stage, connecting the bipolar plates in series by controlling the combined action of the two switching devices, and inputting a second preset current to the stacked electrochemical reactor, wherein the second preset current is equal to or greater than the first preset current.

[0077] Preferably, in the case of connecting the bipolar plates in series or in parallel by controlling the combined action of the two switching devices, the control method further comprises: when the stacked electrochemical reactor is in a pre-reaction heating stage, connecting the bipolar plates in the same way as in the heat preservation stage by controlling the combined action of the two switching devices, and inputting a second preset current to the stacked electrochemical reactor, wherein the second preset current is greater than the first preset current.

[0078] The specific details and benefits of the thermal management system provided by the embodiment of the present application can be referred to the description of the thermal management method above, and will not be described here.

[0079] An embodiment of the present application provides a stacked electrochemical reactor comprising the thermal management system.

[0080] The preferred embodiments of the present application are described in detail above with reference to the accompanying drawings, but the present application is not limited to the specific details in the above-described embodiments, and various simple modifications can be made to the technical solutions of the present application within the technical concept of the present application, and these simple modifications all belong to the protection scope of the present application.

[0081] In addition, it should be noted that various technical features described in the above embodiments can be combined in any suitable manner, and the present application will not be repeated in the description of various possible combinations.

[0082] Those skilled in the art can understand that all or part of the steps of the methods in the above embodiments can be completed by programs instructing relevant hardware, and the programs are stored in a storage medium, including a plurality of instructions for enabling a single-chip microcomputer, a chip or a processor to execute all or part of the steps of the methods described in various embodiments of the present application. The foregoing storage medium includes a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various media that can store program codes.

[0083] Those skilled in the art can understand that the embodiments of the present application can be provided as a method, a system or a computer program product. Therefore, the present application can be in the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. In addition, the present application can be in the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0084] The present application is described with reference to flowcharts and / or block diagrams of methods, devices (systems) and computer program products according to embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of flows and / or blocks in the flowcharts and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be provided to a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing devices to produce a machine, so that the instructions executed by the computer or other programmable data processing devices produce a device that implements the functions specified in one or more flows in the flowcharts and / or one or more blocks in the block diagrams.

[0085] In addition, various different embodiments of the present application can also be combined in any suitable manner, as long as they do not deviate from the idea of the present application, and they should also be considered as disclosed by the present application.

Claims

1. A thermal management system, characterized by, The application relates to a thermal management system suitable for a stacked electrochemical reactor, the stacked electrochemical reactor comprising a plurality of electrochemical reaction units, each of the electrochemical reaction units comprising a pair of bipolar plates and an electrochemical reaction medium, wherein each of the bipolar plates is configured with tabs on both sides, the width of the tabs being at least a preset proportion of the length of the short side of the bipolar plate, the thermal management system comprising: two switch device combinations, each of the switch device combinations being located on one side of the plurality of electrochemical reaction units and connected to the tabs on the corresponding side; and a control device configured to control the two switch device combinations to connect the bipolar plates in series or in parallel and input a first preset current to the stacked electrochemical reactor when the stacked electrochemical reactor is in a heat preservation stage.

2. The thermal management system of claim 1, wherein, In the case where the control device is configured to control the two switch device combinations to connect the bipolar plates in parallel, the control device is further configured to control the two switch device combinations to connect the bipolar plates in series and input a second preset current to the stacked electrochemical reactor when the stacked electrochemical reactor is in a pre-reaction heating stage, wherein the second preset current is equal to or greater than the first preset current.

3. The thermal management system of claim 1, wherein, In the case where the control device is configured to control the two switch device combinations to connect the bipolar plates in series or in parallel, the control device is further configured to control the two switch device combinations to connect the bipolar plates in the same way as in the heat preservation stage and input a second preset current to the stacked electrochemical reactor when the stacked electrochemical reactor is in a pre-reaction heating stage, wherein the second preset current is greater than the first preset current.

4. The thermal management system of any one of claims 1-3, wherein, The switch device combination comprises a plurality of control switch pairs, the control switches in the control switch pairs being connected in series with the corresponding bipolar plates via the corresponding tabs, and a plurality of connection switches, the connection switches connecting two adjacent control switches.

5. The thermal management system of any one of claims 1-3, wherein, The switch device combination comprises a plurality of control switches distributed in a two-part management structure.

6. The thermal management system of any one of claims 1-3, wherein, The thermal management system further comprises a voltage detector configured to monitor the electromotive force between any two bipolar plates when the stacked electrochemical reactor is in a reaction stage.

7. A thermal management method, characterized by, The application relates to a thermal management method suitable for a stacked electrochemical reactor, the stacked electrochemical reactor comprising a plurality of electrochemical reaction units, each of the electrochemical reaction units comprising a pair of bipolar plates and an electrochemical reaction medium, wherein each of the bipolar plates is configured with tabs on both sides for connecting an external circuit, the width of the tabs being at least a preset proportion of the length of the short side of the bipolar plate, the thermal management method comprising: determining the stage of the stacked electrochemical reactor; and controlling two switch device combinations to connect the bipolar plates in series or in parallel and input a first preset current to the stacked electrochemical reactor when the stacked electrochemical reactor is in a heat preservation stage, wherein each of the switch device combinations is located on one side of the plurality of electrochemical reaction units and connected to the tabs on the corresponding side.

8. The thermal management method of claim 7, wherein, In the case of connecting the bipolar plates in parallel by controlling the combined action of the two switching devices, the control method further comprises: In the case of connecting the bipolar plates in parallel by controlling the combined action of the two switching devices, the control method further comprises:

9. The thermal management method of claim 7, wherein, In the case of connecting the bipolar plates in series or in parallel by controlling the combined action of the two switching devices, the control method further comprises: In the case of connecting the bipolar plates in series or in parallel by controlling the combined action of the two switching devices, the control method further comprises:

10. A stacked electrochemical reactor characterized by, In the case of connecting the bipolar plates in series or in parallel by controlling the combined action of the two switching devices, the control method further comprises: The stacked electrochemical reactor comprises the thermal management system according to any one of claims 1-6.

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