Current density detection composite plate and battery current density online detection device

Abstract

The present invention provides a current density detection composite plate, comprising: a detection plate, the detection plate comprising a plate body, a detection unit, a first insulating member and a circuit board or a first conductive wire; the detection unit comprising two conductive sheets spaced apart from each other, and a standard resistor whose two ends are connected to the two conductive sheets in a one-to-one correspondence; a flow field plate, one side of the flow field plate is fitted and connected to one side of the plate body and is conductive with one of the conductive sheets, and a flow channel is provided on the other side of the flow field plate. An online detection device for the internal current density of a battery comprises the above-mentioned current density detection composite plate. The current density detection composite plate provided by the present invention can be matched with different flow field plates through a detection plate to achieve the purpose of being able to detect the current density of bipolar plates, anode plates and cathode plates of different designs and any position in the battery stack, and has good interchangeability. At the same time, it does not need to have a gas isolation function, and it is not necessary to process the flow channel on the conductive sheet of the detection unit, which reduces the difficulty of making the detection plate.

Description

Technical Field

[0001] The invention belongs to the technical field of fuel cell testing, and more specifically, relates to a current density detection composite plate and an online measuring device for detecting current density in a fuel cell. Background Art

[0002] Fuel cells are power generation devices that convert chemical energy in fuels directly into electrical energy through electrochemical reactions. Fuel cells have been around for more than 100 years since their invention. As energy and environment have become key issues for the survival of human society, over the past 20 years, fuel cells, a highly efficient and clean energy conversion device, have received widespread attention from governments, developers and research institutions around the world, and have shown broad application prospects in civil and military fields such as transportation, portable power supplies, decentralized power stations, aerospace and underwater submersibles.

[0003] The current density inside the fuel cell is a comprehensive reflection of the electrochemical reaction under the influence of factors such as reactants, temperature and water distribution in the battery. If the current density distribution is uneven, it means that the utilization rate of each area of ​​the active area is uneven, resulting in local voltage differences and in-plane current, causing potential loss. In addition, when the membrane electrode passes through the hole, the current density will reverse.

[0004] Online partitioned current density testing technology can test the local current density distribution of the fuel cell in real time and accurately, thereby reflecting the differences in electrochemical reactions inside the battery. It is of great significance to improving battery flow field design and avoiding major safety accidents caused by membrane electrode attenuation through the hole.

[0005] At present, the main current density tests include the inertial network resistance method, the first circuit board method and the Hall sensor method. The inertial network resistance method is mainly used for single-cell current density testing. The first circuit board method cannot process the flow channel due to printing thickness limitations, so it cannot be placed as a bipolar plate at any position inside the battery stack for current density measurement. The installation steps of the Hall sensor inside the plate are cumbersome and the detection accuracy is not high, so it is not suitable for current density detection at any position inside the battery stack. Different detection devices need to be replaced for different flow fields, and the interchangeability is poor, which increases the cost of the detection device. Summary of the invention

[0006] The object of the present invention is to provide a current density detection composite plate to solve the technical problem in the prior art that different detection devices need to be replaced for different flow fields, which increases the cost of the detection device.

[0007] To achieve the above object, the technical solution adopted by the present invention is: to provide a current density detection composite plate, comprising:

[0008] A detection board, the detection board comprising a board body with a middle active area, the middle active area being divided into a plurality of first partitions distributed in a matrix, the middle active area also being provided with a through slot; the detection board further comprising a detection unit at least partially disposed in the through slot and corresponding to the first partition, a first insulating member disposed between adjacent detection units, and a circuit board or a first wire embedded in the board body and electrically connected to the detection unit; the detection unit comprising two conductive sheets disposed at intervals from each other, and a standard resistor having two ends connected to the two conductive sheets in a one-to-one correspondence; the two conductive sheets are disposed close to two side surfaces of the board body, respectively; the standard resistor is disposed in the through slot, or the standard resistor is placed outside the board body;

[0009] A flow field plate, wherein the flow field plate is made of a conductive material, one side of the flow field plate is bonded and connected to one side of the plate body and is conductively connected to one of the conductive sheets, and a flow channel is provided on the other side of the flow field plate, wherein the flow channel is the same as the flow field in the fuel cell, and the detection plate can be bonded and connected to different flow field plates with different flow channels.

[0010] Furthermore, a cooling plate for heat dissipation and temperature reduction is attached to the other side of the plate body.

[0011] Furthermore, both sides of the plate body are smooth surfaces, and the flow field plate and the cooling plate are in contact with the plate body with smooth surfaces.

[0012] Furthermore, a first air hole communicating with the flow channel is opened at both ends of the flow field plate, a second air hole is opened at both ends of the plate body, and a third air hole is opened at both ends of the cooling plate. The first air hole, the second air hole and the third air hole are arranged in correspondence with each other, and a first sealing ring and a second sealing ring are respectively provided at both ends of the second air hole to prevent gas from entering the plate body.

[0013] Furthermore, one side of the flow field plate has second partitions corresponding to the detection units, and the second partitions are insulated from each other.

[0014] Furthermore, the first insulating member is insulating glue; the conductive sheet is a copper sheet, a gold sheet, a silver sheet or a stainless steel sheet; the plate body is made of glass fiber material or PEI material; and the flow field plate is made of graphite or stainless steel material.

[0015] Preferably, the detection board comprises two first circuit boards stacked together, the first circuit boards having welding areas distributed in a matrix, the welding areas of the two first circuit boards being distributed one-to-one, the first circuit boards being provided with through holes corresponding one-to-one to the welding areas, the through holes of the two first circuit boards being correspondingly connected; the first circuit boards being provided with circuit traces electrically connected to the respective welding areas, the first circuit boards being provided with pin sockets at the ends of the circuit traces;

[0016] The plate body includes two insulating frames arranged in a stacked manner, each of the insulating frames has a receiving groove for receiving one of the first circuit boards, two of the first circuit boards are respectively embedded and clamped between the two insulating frames, the insulating frames are provided with mounting holes for receiving the conductive sheets in a one-to-one correspondence on the bottom surface of the receiving groove, the mounting holes are arranged in a one-to-one correspondence with the welding areas, the number of mounting holes of one of the insulating frames is equal to the number of welding areas of one of the first circuit boards, and the insulating frames are provided with insulating ribs between adjacent mounting holes for insulating adjacent conductive sheets; the first insulating member is filled between the conductive sheets and the insulating ribs;

[0017] The number of the standard resistors is equal to the number of the welding areas of one of the first circuit boards, the standard resistors are respectively installed in the through holes corresponding to the two first circuit boards, and the two ends of the standard resistors are respectively electrically connected to the side surfaces of the through holes of the two first circuit boards;

[0018] Each group of the conductive sheets is electrically connected to the outer side surface of each welding area of ​​the first circuit board, and the conductive sheets cover the corresponding through holes;

[0019] The first circuit board is provided with two circuit traces electrically connected to the respective welding areas; the resistance is measured by four wires, and two first test points are respectively provided at the corresponding two welding areas to form two pairs of first test points, one pair of the first test points is connected to the two welding areas as a current supply, and the other pair of the first test points is used to measure voltage and is respectively provided at the two welding areas;

[0020] The first circuit board has a mounting arm, the circuit wiring extends to the mounting arm, the pin socket is provided on the mounting arm; the insulating frame is provided with a through hole for the mounting arm to pass through.

[0021] Preferably, the two conductive sheets are isolated by two second circuit boards, the two second circuit boards are respectively embedded in the board body and at least partially exposed outside the board body, the two conductive sheets are respectively electrically connected to the two second circuit boards, and each standard resistor is respectively attached to the portion of the second circuit board exposed outside the board body.

[0022] Preferably, the plate body is a single-layer structure, a second insulating member is provided between the two conductive sheets, and the standard resistor is provided at the side edges of the two conductive sheets; or, the standard resistor is embedded in the second insulating member; or, the standard resistor is provided on an external third circuit board, and both ends are electrically connected to the two conductive sheets through a second wire respectively; both ends of the standard resistor are connected to a first wire, and the controller is electrically connected to the standard resistor through the first wire to measure the voltage drop across the standard resistor;

[0023] The standard resistor is measured using four wires, and two second test points are respectively set at both ends of the standard resistor, one pair of the second test points is directly connected to the two ends of the standard resistor as a current supply, and the other pair of the second test points is used to measure voltage and is set close to the two ends of the standard resistor;

[0024] The number of the first wires corresponding to one detection unit is four, and one of the connections between the conductive sheets and the standard resistor and one of the connections between the other conductive sheets and the standard resistor in the same detection unit are respectively connected to one of the first wires, and each of the conductive sheets is respectively connected to one of the first wires.

[0025] The present invention also provides an online measurement device for detecting current density in a fuel cell, comprising a fuel cell, the above-mentioned current density detection composite plate arranged in the fuel cell, a controller electrically connected to the fuel cell, and a host computer electrically connected to the controller; the fuel cell comprises a first end plate, a first current collecting plate, an anode plate, a membrane electrode assembly, a cathode plate, a second current collecting plate and a second end plate connected in sequence; the current density detection composite plate is used to replace the anode plate or the cathode plate to detect current density, and the online measurement device for detecting current density in the fuel cell also comprises a voltmeter, and both ends of the voltmeter are respectively connected to the two conductive sheets.

[0026] The beneficial effect of the current density detection composite plate provided by the present invention is that: compared with the prior art, the current density detection composite plate of the present invention includes a detection plate and a flow field plate, by separating the flow field plate from the detection plate, and integrating the plate body, detection unit and circuit board with high manufacturing cost into the detection plate, and setting the flow channel in the flow field plate with low manufacturing cost, so that the flow field plate with different flow channels can be designed according to the needs, and the cathode flow field, the anode flow field and the bipolar flow field can also be designed, so that a detection plate can be matched with different flow field plates to achieve the current density detection of bipolar plates with different designs, and the current density distribution of the anode and cathode plates can be measured or placed at any position in the battery stack for current density detection, which is flexible and risk-free to use and has good interchangeability. In addition, because the flow channel is opened on the other side of the flow field plate, the detection unit does not directly contact the reaction gas in the flow channel during the test, and the detection plate only needs to have a good conductive function, and does not need to have a gas isolation function, and there is no need to process the flow channel on the conductive sheet of the detection unit, which greatly reduces the difficulty of making the detection plate and greatly improves the reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0028] Figure 1 A three-dimensional schematic diagram of a current density detection composite plate provided by the present invention;

[0029] Figure 2 for Figure 1 Schematic diagram of the decomposition of the composite plate for medium current density detection;

[0030] Figure 3 for Figure 1 The structural diagram of the detection board;

[0031] Figure 4 for Figure 1 Schematic diagram of the structure of the mid-flow field plate;

[0032] Figure 5 A schematic diagram of the structure of an online detection device for current density in a fuel cell provided by an embodiment of the present invention;

[0033] Figure 6 A front schematic diagram of a current density detection composite plate provided in Embodiment 1 of the present invention;

[0034] Figure 7 for Figure 1 A schematic diagram of the inner side of the middle insulating frame;

[0035] Figure 8 for Figure 1 A schematic diagram of an internal circuit of the first circuit board;

[0036] Fig. 9 for Figure 8 A partial enlarged view of

[0037] Fig.10 for Figure 6 A partial cross-sectional view of

[0038] Fig.11 A partial schematic diagram of a current density detection composite plate provided in the second embodiment of the present invention;

[0039] Fig.12 This is a partial schematic diagram of the current density detection composite plate provided in the third embodiment of the present invention. DETAILED DESCRIPTION

[0040] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0041] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0042] It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0043] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0044] Please also read Figures 1 to 4Now, the current density detection composite plate 1000 provided by the present invention is described. The current density detection composite plate 1000 includes a detection plate 100 and a flow field plate 200 .

[0045] The detection board 100 includes a board body 1 having a middle active area, the middle active area of ​​the board body 1 is provided with a through groove, and the middle active area is divided into a plurality of first partitions 10 distributed in a matrix; the detection board 100 also includes detection units 2, a first insulating member 3, a circuit board 4 or a first wire, the detection units 2 are at least partially disposed in the through groove and correspond one to one with the first partitions 10, the first insulating member 3 is disposed between adjacent detection units 2, and the circuit board 4 or the first wire is embedded in the board body 1 and electrically connected to the detection units 2; please refer to Fig.12 The detection unit 2 includes two conductive sheets 21 spaced apart from each other, and a standard resistor 22 whose two ends are connected to the two conductive sheets 21 in a one-to-one correspondence, and the two conductive sheets 21 are respectively arranged close to the two side surfaces of the plate body 1. The standard resistor 22 is arranged in the through slot, or the standard resistor 22 is placed outside the plate body 1, that is, as long as the detection unit 2 meets the detection function of the flow field, the standard resistor 22 can be integrated into the plate body 1 or placed outside the plate body 1, which is not limited here.

[0046] The flow field plate 200 is made of conductive material, one side of the flow field plate 200 is connected with one side of the plate body 1 and is in conduction with one of the conductive sheets 21, and the other side of the flow field plate 200 is provided with a flow channel 210, and the detection plate 100 can be connected with different flow field plates 200 with different flow channels 210. The flow channel 210 is the same as the flow field in the fuel cell, and the flow channel 210 can be an anode flow field or a cathode flow field, and the processed flow channel 210 can be of any type.

[0047] When performing current density detection, the current density detection composite plate 1000 is installed at the position to be tested in the battery stack or fuel cell, and then the detection interface (not shown) of the host computer is connected to the circuit board or the first wire, and the voltage drop between the two conductive sheets 21 corresponding to the upper and lower parts of each first partition 10 is detected by fast switching through the existing control circuit. The current density of each first partition 10 can be calculated by dividing the voltage drop by the resistance 22 and area of ​​each first partition 10, that is, the following formula is used:

[0048]

[0049] Wherein, J is the current density, I is the current of each first partition 10 , U is the voltage drop of each first partition 10 , R is the resistance of each first partition 10 , and A is the area size of the first partition 10 .

[0050] The current density detection composite plate 1000 provided by the present invention includes a detection plate 100 and a flow field plate 200. The flow field plate 200 is separated from the detection plate 100, and the plate body 1, the detection unit 2 and the circuit board 4 with high manufacturing cost are integrated into the detection plate 100, and the flow channel 210 is arranged in the flow field plate 200 with low manufacturing cost. In this way, the flow field plate 200 with different flow channels 210 can be designed as needed, and the cathode flow channel 210, the anode flow field and the bipolar flow field can also be designed, so that a detection plate 100 can be matched with different flow field plates 200 to achieve the current density detection of bipolar plates with different designs, and the current density distribution of the cathode and anode plates 4000 can be measured or placed at any position in the battery stack for current density detection. It is flexible to use and risk-free, and has good interchangeability. In addition, because the flow channel 210 is opened on the other side of the flow field plate 200, the detection unit 2 does not directly contact the reaction gas in the flow channel 210 during testing. The detection plate 100 only needs to have a good conductive function and does not need to have a gas isolation function. There is no need to process the flow channel 210 on the conductive sheet 21 of the detection unit 2, which greatly reduces the difficulty of manufacturing the detection plate 100 and greatly improves its reliability.

[0051] Preferably, in this embodiment, please refer to Figure 1 and Figure 2 , a cooling plate 300 is also attached to the other side of the plate body 1, and the cooling plate 300 is used to dissipate the heat generated inside the fuel cell and has a cooling effect. It can be understood that in other embodiments of the present invention, the cooling plate 300 may not be attached to the other side of the plate body 1, but may be set at other parts of the fuel cell. For example, when the current density detection composite plate 1000 is used to replace the cathode plate of the fuel cell, the cooling plate 300 may be set between the current collecting plate and the anode plate, and vice versa, which is not limited here.

[0052] Preferably, in this embodiment, please refer to Figures 1 to 4 Both sides of the plate body 1 are smooth, and the flow field plate 200 and the cooling plate 300 are in contact with the plate body 1 with smooth surfaces. In this way, the two sides of the plate body 1 can be tightly fitted with the flow field plate 200 and the cooling plate 300 respectively, with good sealing effect, which can prevent gas from entering the detection unit 2 of the detection plate 100 to affect the detection result.

[0053] Furthermore, first air holes 220 communicating with the flow channel 210 are provided at both ends of the flow field plate 200, second air holes 110 are provided at both ends of the plate body 1, and third air holes 310 are provided at both ends of the cooling plate 300. The first air holes 220, the second air holes 110 and the third air holes 310 are arranged in correspondence with each other, and the first sealing ring 400 and the second sealing ring 500 are respectively provided at both ends of the second air hole 110 to prevent gas from entering the plate body 1. Through the arrangement of the first sealing ring 400 and the second sealing ring 500, the gas in the flow channel 210 can be further prevented from entering the detection unit 2 in the plate body 1 through the air holes, thereby ensuring that the detection effect of the detection unit 2 is good.

[0054] Specifically, a first sealing groove 230 is provided on one side of the flow field plate 200, the first sealing groove 230 is arranged around the periphery of the first air hole 220, and a first sealing ring 400 is partially arranged in the first sealing groove 230 and abuts between the flow field plate 200 and the plate body 1. Similarly, a second sealing groove 320 is provided on one side of the cooling plate 300 that is in contact with the plate body 1, the second sealing groove 320 is arranged around the periphery of the third air hole 310, and a second sealing ring 500 is partially arranged in the second sealing groove 320 and abuts between the cooling plate 300 and the plate body 1.

[0055] In this example, see Figure 4 , a second partition 240 corresponding to each detection unit 2 is provided on one side of the flow field plate 200, and each second partition 240 is insulated from each other. Specifically, the second partition 240 can be formed by milling a groove on one side of the flow field plate 200, and the milling groove is filled with insulating glue for blocking. One second partition 240 corresponds to one detection unit 2, and the side of the flow field plate 200 opposite to the second partition 240 is the flow channel 210. In this way, one second partition 240 is combined with one detection unit 2 to form a partition unit for detecting the flow channel 210, and cooperates with the data acquisition system to scan and detect the voltage drop of each detection unit in turn.

[0056] Preferably, in this embodiment, adjacent detection units 2 are spaced apart, and the first insulating member 3 is an insulating resin. Gaps are left between the first partitions 10, and insulating resin is filled to insulate them from each other, so as to ensure the relative independence of the test results of each first partition 10. It can be understood that in other embodiments of the present invention, the first insulating member 3 can also be other high temperature resistant insulating glue, which is not limited here.

[0057] Preferably, in this embodiment, the conductive sheet 21 is a copper sheet, both sides of the copper sheet are smooth, and the standard resistor 22 is connected to the copper sheet by welding. It can be understood that in other embodiments of the present invention, the conductive sheet 21 can also be a gold sheet, a silver sheet or a stainless steel sheet, which is not limited here.

[0058] Preferably, in this embodiment, the plate body 1 is made of glass fiber material or PEI material, which is not only insulating but also has the property of high temperature resistance.

[0059] Preferably, in this embodiment, the flow field plate 200 is made of graphite, which is conductive and easy to process various flow channels 210. It can be understood that in other embodiments of the present invention, the flow field plate 200 can also use other conductive and easy to process materials, such as stainless steel, which is not limited here.

[0060] See also Figure 5 The present invention also provides an online measuring device for detecting current density in a fuel cell. The online measuring device for detecting current density in a fuel cell comprises a fuel cell, a current density detection composite plate 1000 arranged in the fuel cell, a controller electrically connected to the fuel cell, and a host computer electrically connected to the controller; the fuel cell comprises a first end plate 2000, a first current collecting plate 3000, an anode plate 4000, a membrane electrode assembly 5000, a cathode plate 6000, a second current collecting plate 7000 and a second end plate 8000 connected in sequence. The current density detection composite plate 1000 is used to replace the anode plate 4000 or the cathode plate 6000 to detect current density. The online measuring device for detecting current density in a fuel cell also comprises a voltmeter 9000, and both ends of the voltmeter 9000 are respectively connected to two conductive sheets 21.

[0061] The current density detection composite plate 1000 is used to replace the anode plate 4000 or the cathode plate 6000. The current density detection composite plate 1000 is placed at different positions in the fuel cell or the stack according to the needs to realize the online monitoring of the current density in the stack. In addition, the outer side surface of all the conductive sheets 21 located on one side is provided with a flow channel 210, and the flow field structure is completely consistent with the standard single cell flow field actually used in the stack. No new interference factors are introduced due to the measurement, and the stack structure, flow field structure and contact parts are not changed, and the structure of the stack is not affected.

[0062] Embodiment 1:

[0063] See also Figures 6 to 10The detection board 100 includes two first circuit boards 40 stacked together. The first circuit boards 40 have welding areas 41 distributed in a matrix. The welding areas 41 of the two first circuit boards 40 are distributed one by one. The first circuit boards 40 are provided with through holes 42 corresponding to the welding areas 41. The through holes 42 of the two first circuit boards 40 are connected to each other. The first circuit boards 40 are provided with circuit traces 43 electrically connected to the respective welding areas 41. The first circuit boards 40 are provided with pin sockets 44 at the ends of the circuit traces 43. The board body 1 includes two insulating frames 10 stacked together. Each insulating frame 10 has a In the receiving groove 11 for receiving a first circuit board 40, two first circuit boards 40 are respectively embedded and clamped between two insulating frames 10. The insulating frame 10 is provided with mounting holes 12 on the bottom surface of the receiving groove 11 for correspondingly receiving the conductive sheets 21. The mounting holes 12 are arranged in a one-to-one correspondence with the welding areas 41. The number of mounting holes 12 of an insulating frame 10 is equal to the number of welding areas 41 of a first circuit board 40. The insulating frame 10 is provided with insulating ribs 13 between adjacent mounting holes 12 for insulating adjacent conductive sheets 21. The corresponding two mounting holes 12 and two through holes 42 are combined to form the above-mentioned through groove. The number of standard resistors 22 is equal to the number of welding areas 41 of a first circuit board 40. The standard resistors 22 are respectively installed in the corresponding through holes 42 of the two first circuit boards 40, and the two ends of the standard resistors 22 are respectively electrically connected to the side surfaces of the through holes 42 of the two first circuit boards 40; each group of conductive sheets 21 is electrically connected to the outer side surfaces of each welding area 41 of a first circuit board 40, and the conductive sheets 21 cover the corresponding through holes 42. One conductive sheet 21 in one group of conductive sheets 21, the corresponding welding area 41 of the first circuit board 40, the corresponding standard resistor 22, the corresponding welding area 41 of another first circuit board 40, and the corresponding conductive sheet 21 in another group of conductive sheets 21 are connected in series, and a first partition 10 is formed in the area where the two conductive sheets 21 are located.

[0064] A standard resistor 22 is installed in the through hole 42 of two first circuit boards 40, and the two ends of the standard resistor 22 are respectively connected to the side surfaces of the through holes 42 of the two first circuit boards 40. The first circuit boards 40 are embedded and installed in two insulating frames 10 to form a composite board, thereby obtaining a current density detection composite board 1000. The standard resistor 22 used has the advantages of small size, high precision and very small temperature coefficient, which can greatly improve the measurement accuracy of current density. In addition, the installation steps of the standard resistor 22 are simple and the operation is easy; the embedded installation can avoid affecting the battery structure, and at the same time can greatly reduce the thickness of the current density detection composite plate 1000, which is very convenient to install at any position of the battery stack, and realize the current density measurement at any position in the three-dimensional space inside the battery stack, and the measurement is stable and reliable; the use of the first circuit board 40 can make the wiring neat and reliable, and can avoid the short circuit phenomenon in each area, greatly reducing the complexity of assembly and low production cost. The pin socket 44 is opened on the first circuit board 40, which is very convenient for voltage collection and wiring during current density measurement; the conductive sheet 21 is installed on the first circuit board 40 to realize the processing of the flow channel 210, which solves the problem that the copper foil is too thin to process the flow channel 210 when the first circuit board 40 is used directly.

[0065] It can be understood that in the present invention, the first circuit board 40 is a printed circuit board, and can also be a flexible circuit board, which is not limited here.

[0066] The first circuit board 40 has a positioning hole 45. The positioning holes 45 of the two first circuit boards 40 are aligned and welded to prevent the first circuit boards 40 from being misaligned when other parts are welded. The through hole 42 of the first circuit board 40 is a square hole or a circular hole, which is easy to process and facilitates the welding of the end of the standard resistor 22 to the side of the through hole 42 of the first circuit board 40.

[0067] The conductive sheet 21 is rectangular, and the welding area 41 is rectangular in shape, which is easy to shape and can be very convenient for positioning the conductive sheet 21 during welding. The welding area 41 includes a rectangular portion and a frame portion connected to one side of the rectangular portion. A filling area for filling solder is provided in the rectangular portion, and a through hole 42 is provided in the frame portion. This structure is easy to shape and is convenient for connecting the conductive sheet 21 to the welding area 41.

[0068] The standard resistor 22 can be a chip standard resistor 22 or a color ring standard resistor 22, which has the advantages of small size, high precision and very small temperature coefficient. The size of the standard resistor 22 is not greater than 10mm*10mm*2mm, the resistance of the standard resistor 22 is 5-10 milliohms, the power of the standard resistor 22 is greater than 1W, and it can withstand a large current of at least 10A. At the same time, when the temperature changes from 25℃ to 120℃, the temperature coefficient of the standard resistor 22 is not greater than 1%. The volume of the chip standard resistor 22 is 5mm*3mm*0.6mm.

[0069] Furthermore, the first insulating member 3 (insulating glue) is filled between the conductive sheet 21 and the insulating rib 13, and the insulating glue is also filled between the insulating frame 10 and the first circuit board 40. The insulating glue has strong bonding force, high temperature resistance, and corrosion resistance, and achieves insulation and sealing. The insulating glue adopts a single-component epoxy resin or other structural glue with strong bonding, high temperature resistance (applicable temperature -40°C to 140°C), and corrosion resistance, which can achieve insulation between the partitions of the current density detection composite board 1000.

[0070] For further information, see Figure 8 , Fig. 9 , the first circuit board 40 is provided with two circuit traces 43 corresponding to each welding area 41 and electrically connected; the standard resistor 22 adopts four-wire measurement, and two corresponding welding areas 41 are respectively provided with two first test points to form two pairs of first test points, one pair of first test points is connected to the two welding areas 41 (i.e., the two ends of the standard resistor 22) as current supply, and the other pair of first test points is used to measure voltage and is respectively provided in the two welding areas 41 and is provided close to the two ends of the standard resistor 22. The first test point for measuring voltage is closer to the end of the standard resistor 22 than the first test point for current supply, and the pair of first test points for measuring voltage is inside, and the pair of first test points for current supply is outside. The first circuit boards 40 corresponding to the upper and lower parts each lead out two circuit traces 43 to the pin socket 44, which is convenient for accurate calibration of the standard resistors 22 in each partition after installation. The resistance value of the standard resistor 22 changes with temperature. The four-wire method is used to measure the resistance value of the standard resistor 22, eliminating the influence of the measuring line resistance. Since the impedance of the voltage measurement loop is very high, the current flowing through the voltage lead is very small and can be ignored, so the resistance value of the measured standard resistor 22 is equal to the voltage measured by the voltage lead divided by the current passing through the current lead, effectively eliminating the error caused by the lead standard resistor 22, and achieving accurate measurement of the resistance value of the measured standard resistor 22. This method accurately calibrates the standard resistor 22 value of each standard resistor 22 used for current density measurement at any operating temperature at any time, ensuring accurate measurement of the voltage drop across the standard resistor 22 and avoiding temperature interference causing current density calculation errors.

[0071] For further information, see Figure 5 , Figure 6 , Figure 8 , Fig. 9 The first circuit board 40 has a mounting arm 46, the circuit trace 43 extends to the mounting arm 46, and the pin socket 44 is provided on the mounting arm 46; the insulating frame 10 is provided with a through hole 17 for the mounting arm 46 to pass through. This structure facilitates the insertion of the detection interface of the host computer into the pin socket 44 of the first circuit board 40, and facilitates the assembly of the mounting arm 46 on the insulating frame 10, so that the overall structure has a small thickness.

[0072] Furthermore, the first circuit board 40 has at least two mounting arms 46. The mounting arms 46 of the two first circuit boards 40 are staggered. This structure is easy to form and assemble, and is convenient for inserting the detection interface of the host computer into the pin socket 44 of the first circuit board 40, so as to perform current density tests on more partitions. The mounting arms 46 are distributed on both sides of the first circuit board 40, so as to insert the detection interface of the host computer into the pin socket 44 of the first circuit board 40, so as to perform current density tests on more partitions.

[0073] Furthermore, the two ends of the standard resistor 22 are electrically connected to the side surfaces of the through holes 42 of the two first circuit boards 40 by welding; this structure is easy to form and realizes the electrical connection between the two. Each group of conductive sheets 21 is electrically connected to the outer side surfaces of each welding area 41 of a first circuit board 40 by welding. This structure is easy to form and realizes the electrical connection between the two.

[0074] For further information, see Figure 8 and Fig. 9 The first circuit board 40 is provided with a filling groove 47 corresponding to the welding area 41, and the filling groove 47 is filled with solder. The filling groove 47 is in an I-shaped shape, and the solder is applied to the end of the filling groove 47 away from the standard resistor 22, so as to accommodate enough solder to weld the conductive sheet 21. At the same time, the filling of tin in the filling groove 47 can increase the maximum current value that each partition can withstand. The solder in the filling groove 47 is heated to a molten state with an electric soldering iron, and then the conductive sheet 21 is quickly covered and aligned with the welding area 41 pre-arranged on the first circuit board 40, and the electric soldering iron is adjusted to 400°C to heat the corresponding part of the filling groove 47 on the upper surface of the conductive sheet 21 until the conductive sheet 21 is completely fitted and soldered to the first circuit board 40.

[0075] Embodiment 2:

[0076] The technical features of the current density detection composite plate 1000 in this embodiment are substantially the same as those of the current density detection composite plate 1000 in the first embodiment, except that: in this embodiment, refer to Fig.11 , the standard resistor 22 is placed outside the board body 1. Specifically, the conductive sheets 21 are isolated by two second circuit boards 60, the two second circuit boards 60 are respectively embedded in the board body 1 and at least partially exposed outside the board body 1, the two conductive sheets 21 are respectively electrically connected to the two second circuit boards 60, and each standard resistor 22 is respectively attached to the portion of the second circuit board 60 exposed outside the board body 1.

[0077] In addition, the board body 1 may be composed of two insulating frames, in which case the two second circuit boards 60 are attached to each other and clamped between the two insulating frames; the board body 1 may also be directly a single-layer structure, in which case the two second circuit boards 60 are attached to each other and embedded between the board body 1, and at least partially exposed outside the board body 1.

[0078] Embodiment three:

[0079] The technical features of the current density detection composite plate 1000 in this embodiment are substantially the same as those of the current density detection composite plate 1000 in the first embodiment, except that: in this embodiment, refer to Fig.12 The board body 1 is a single-layer structure, a second insulating member 23 is provided between the two conductive sheets 21, and the standard resistor 22 is provided at the side edges of the two conductive sheets 21; or, the standard resistor 22 is embedded in the second insulating member 23; or, the standard resistor 22 is provided on an external third circuit board, and both ends are electrically connected to the two conductive sheets 21 through a second wire respectively; both ends of the standard resistor 22 are connected to a first wire 24, and an external controller is electrically connected to the standard resistor 22 through the first wire 24 to measure the voltage drop across the standard resistor 22.

[0080] In each detection unit 2, a second insulating member 23 is provided between two conductive sheets 21, and both ends of the standard resistor 22 are respectively connected to the two conductive sheets 21, with a compact structure. The controller measures the voltage drop across the standard resistor 22, and converts the current density by combining the standard resistor 22 with the area of ​​the conductive sheet 21. This realizes synchronous online monitoring of the current density inside the battery, and truly and vividly reflects the current density distribution during the battery operation process.

[0081] Preferably, the second insulating member 23 is an insulating glue, and the second insulating member 23 is bonded between the two conductive sheets 21 of the same detection unit 2. This structure is easy to assemble, and the assembly of the two conductive sheets 21 is realized, and the overall structure is compact.

[0082] Furthermore, in the present embodiment, the standard resistor 22 is measured by four wires, and two second test points are respectively set at both ends of the standard resistor 22, wherein a pair of the second test points are directly connected to both ends of the standard resistor 22 as current supply, and another pair of the second test points are used to measure the voltage and are set close to both ends of the standard resistor 22. The resistance of the standard resistor 22 changes with temperature, and the resistance of the standard resistor 22 is measured by the four-wire method, eliminating the influence of the measurement line resistance. Since the impedance of the measurement voltage loop is very high, the current flowing through the voltage lead is very small and can be ignored, so the resistance of the measured standard resistor 22 is equal to the voltage measured by the voltage lead divided by the current passing through the current lead, effectively eliminating the error caused by the lead standard resistor 22, and realizing the accurate measurement of the resistance of the measured standard resistor 22. This method accurately calibrates the standard resistor 22 value of each standard resistor 22 used for current density measurement at any operating temperature at any time, ensures accurate measurement of the voltage drop across the standard resistor 22, and avoids temperature interference causing current density calculation errors.

[0083] Furthermore, the number of first wires 24 corresponding to one detection unit 2 is four, and a first wire 24 is connected to the connection between one conductive sheet 21 and the standard resistor 22 and another conductive sheet 21 and the standard resistor 22 in the same detection unit 2, respectively, and each conductive sheet 21 is connected to a first wire 24. This structure is easy to connect, and the resistance value of the standard resistor 22 is measured by a four-wire method, eliminating the influence of the measurement line resistance, and facilitating accurate measurement of the voltage drop between the two conductive sheets 21.

[0084] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. Current density detection composite plate, characterized in that, include: A detection board, the detection board comprising a board body with a middle active area, the middle active area being divided into a plurality of first partitions distributed in a matrix, the middle active area also being provided with a through slot; the detection board further comprising a detection unit at least partially disposed in the through slot and corresponding to the first partition, a first insulating member disposed between adjacent detection units, and a circuit board or a first wire embedded in the board body and electrically connected to the detection unit; the detection unit comprising two conductive sheets disposed at intervals from each other, and a standard resistor having two ends connected to the two conductive sheets in a one-to-one correspondence; the two conductive sheets are disposed close to two side surfaces of the board body, respectively; the standard resistor is disposed in the through slot, or the standard resistor is placed outside the board body; A flow field plate, wherein the flow field plate is made of a conductive material, one side of the flow field plate is bonded and connected to one side of the plate body and is in conduction with one of the conductive sheets, and the other side of the flow field plate is provided with a flow channel, and the flow channel is the same as the flow field in the fuel cell, and the detection plate can be bonded and connected to different flow field plates with different flow channels; A cooling plate for heat dissipation and temperature reduction is also attached to the other side of the plate body; One side of the flow field plate has second partitions corresponding to the detection units, and the second partitions are insulated from each other.

2. The current density detection composite plate according to claim 1, characterized in that: Both sides of the plate body are smooth surfaces, and the flow field plate and the cooling plate are in contact with the plate body with smooth surfaces.

3. The current density detection composite plate according to claim 1, characterized in that: The flow field plate is provided with a first air hole at both ends thereof which is communicated with the flow channel, the plate body is provided with a second air hole at both ends thereof, and the cooling plate is provided with a third air hole at both ends thereof. The first air hole, the second air hole and the third air hole are arranged in correspondence with each other and are communicated with each other. The first sealing ring and the second sealing ring are respectively provided at both ends thereof to prevent gas from entering the plate body.

4. The current density detection composite plate according to claim 1, characterized in that: The first insulating member is insulating glue; the conductive sheet is a copper sheet, a gold sheet, a silver sheet or a stainless steel sheet; the plate body is made of glass fiber material or PEI material; and the flow field plate is made of graphite or stainless steel material.

5. The current density detection composite plate according to any one of claims 1 to 4, characterized in that: The detection board comprises two first circuit boards stacked in layers, the first circuit boards having welding areas distributed in a matrix, the welding areas of the two first circuit boards being distributed one by one, the first circuit boards being provided with through holes corresponding to the welding areas one by one, the through holes of the two first circuit boards being connected to each other; the first circuit boards being provided with circuit traces electrically connected to the respective welding areas, the first circuit boards being provided with pin sockets at the ends of the circuit traces; The plate body includes two insulating frames arranged in a stacked manner, each of the insulating frames has a receiving groove for receiving one of the first circuit boards, two of the first circuit boards are respectively embedded and clamped between the two insulating frames, the insulating frames are provided with mounting holes for receiving the conductive sheets in a one-to-one correspondence on the bottom surface of the receiving groove, the mounting holes are arranged in a one-to-one correspondence with the welding areas, the number of mounting holes of one of the insulating frames is equal to the number of welding areas of one of the first circuit boards, and the insulating frames are provided with insulating ribs between adjacent mounting holes for insulating adjacent conductive sheets; the first insulating member is filled between the conductive sheets and the insulating ribs; The number of the standard resistors is equal to the number of the welding areas of one of the first circuit boards, the standard resistors are respectively installed in the through holes corresponding to the two first circuit boards, and the two ends of the standard resistors are respectively electrically connected to the side surfaces of the through holes of the two first circuit boards; Each group of the conductive sheets is electrically connected to the outer side surface of each welding area of ​​the first circuit board, and the conductive sheets cover the corresponding through holes; The first circuit board is provided with two circuit traces electrically connected to the respective welding areas; the standard resistance is measured by four wires, and two first test points are respectively provided at the corresponding two welding areas to form two pairs of first test points, one pair of the first test points is connected to the two welding areas as a current supply, and the other pair of the first test points is used to measure voltage and is respectively provided at the two welding areas; The first circuit board has a mounting arm, the circuit wiring extends to the mounting arm, the pin socket is provided on the mounting arm; the insulating frame is provided with a through hole for the mounting arm to pass through.

6. The current density detection composite plate according to any one of claims 1 to 4, characterized in that: The two conductive sheets are isolated by two second circuit boards, the two second circuit boards are respectively embedded in the board body and at least partially exposed outside the board body, the two conductive sheets are respectively electrically connected to the two second circuit boards, and each standard resistor is respectively attached to the portion of the second circuit board exposed outside the board body.

7. The current density detection composite plate according to any one of claims 1 to 4, characterized in that: The board body is a single-layer structure, a second insulating member is provided between the two conductive sheets, and the standard resistor is provided at the side edges of the two conductive sheets; or, the standard resistor is embedded in the second insulating member; or, the standard resistor is provided on an external third circuit board, and both ends are electrically connected to the two conductive sheets through a second wire respectively; both ends of the standard resistor are connected to a first wire, and the controller is electrically connected to the standard resistor through the first wire to measure the voltage drop across the standard resistor; The standard resistor is measured using four wires, and two second test points are respectively set at both ends of the standard resistor, one pair of the second test points is directly connected to the two ends of the standard resistor as a current supply, and the other pair of the second test points is used to measure voltage and is set close to the two ends of the standard resistor; The number of the first wires corresponding to one detection unit is four, and one of the connections between one of the conductive sheets and the standard resistor and one of the connections between another conductive sheet and the standard resistor in the same detection unit are respectively connected to a first wire, and each of the conductive sheets is respectively connected to a first wire.

8. An online measuring device for detecting current density in a fuel cell, characterized in that: It comprises a fuel cell, a current density detection composite plate as described in any one of claims 1 to 7 arranged in the fuel cell, a controller electrically connected to the fuel cell, and a host computer electrically connected to the controller; the fuel cell comprises a first end plate, a first current collecting plate, an anode plate, a membrane electrode assembly, a cathode plate, a second current collecting plate and a second end plate connected in sequence; the current density detection composite plate is used to replace the anode plate or the cathode plate to detect the current density, and the current density detection online measurement device in the fuel cell also comprises a voltmeter, and the two ends of the voltmeter are respectively connected to the two conductive sheets.

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