Single cell testing method, battery stack preparation method, and fuel cell

Abstract

The present application provides a single-cell battery testing method, a method for preparing a fuel cell stack, and a fuel cell. The single-cell battery testing method includes: installing a single-cell battery on a substrate; lowering a pressure plate, with a first preset spacing between the pressure plate and the substrate, the first preset spacing being equal to the designed thickness of the single-cell battery; measuring multiple first pressures between the pressure plate and the single-cell battery using multiple pressure sensors; and determining whether the single-cell battery is qualified in its initial state based on the multiple first pressures. After the pressure plate and the substrate have the first preset spacing, the present application uses multiple pressure sensors on the pressure plate to measure the multiple first pressures between the plate and the single-cell battery. The multiple first pressures can be used to determine whether the single-cell battery is qualified across its entire area, allowing for a more comprehensive assessment of whether the single-cell battery meets standards and avoiding the phenomenon of local defects in the single-cell battery going unidentified.

Description

Technical Field

[0001] The present application relates to the field of new energy technology, and specifically to a single cell battery testing method, a battery stack preparation method, and a fuel cell. Background Art

[0002] Currently, a fuel cell stack can be formed by stacking multiple single cells. Each cell includes a membrane electrode (MEA) and cathode and anode plates located on either side of the MEA. A hydrogen flow field is formed between the anode plate and the MEA, while an oxygen flow field is formed between the cathode plate and the MEA. During the reaction, hydrogen on the anode side of the MEA reacts to produce protons, which then pass through oxygen on the cathode side of the MEA to produce water. Because a large amount of heat is generated during the reaction, a sealed cooling water flow field is required between adjacent cells through seals to absorb the heat generated by the reaction.

[0003] After multiple single cell stacks are assembled to form a fuel cell stack, it is usually necessary to apply a certain amount of pressure to the stack to ensure the sealing and conductivity between adjacent single cells. Since applying pressure to the stack will cause the single cells to be compressed, the size of the stack after compression is uncontrollable, so currently the single cells are usually subjected to compression testing. However, the current single cell compression test method is usually to apply a specific pressure on the single cell and measure the thickness of the single cell to determine whether it meets the standard. Due to the large area of ​​the single cell, it is difficult to comprehensively evaluate whether the single cell is qualified over the entire area. Summary of the Invention

[0004] The present application provides a single cell testing method, a method for preparing a fuel cell stack, and a fuel cell, aiming to solve the technical problem that the current single cell testing method is difficult to comprehensively evaluate whether the single cell is qualified.

[0005] In a first aspect, the present application provides a single-cell battery testing method, which is applied to a single-cell battery testing device. The single-cell battery testing device includes a pressure plate and a base plate arranged relative to each other, and a plurality of pressure sensors are arranged on a side of the pressure plate facing the base plate. The method includes:

[0006] Mounting single cells on a substrate;

[0007] Lowering the pressing plate causes the single battery to assume an initial state, wherein the initial state is a state in which the single battery contacts the pressing plate when the pressing plate is lowered to a first preset distance from the base plate, wherein the first preset distance is equal to the design thickness of the single battery, which is the ideal thickness of the single battery before the surface is flat and compressed;

[0008] Measuring a plurality of first pressures between the pressure plate and the single battery cells by using a plurality of pressure sensors;

[0009] It is determined whether the single battery is qualified in the initial state according to the plurality of first pressures.

[0010] In some embodiments, the step of determining whether a single battery is qualified based on the plurality of first pressures includes:

[0011] When any of the first pressures is greater than a first preset value, the single battery is judged to be unqualified in the initial state;

[0012] When the plurality of first pressures are all less than the first preset value, it is determined that the single battery is qualified in the initial state.

[0013] In some embodiments, the step of determining whether a single battery is qualified in an initial state based on a plurality of first pressures includes:

[0014] Calculating an average pressure based on first pressures measured by any adjacent pressure sensors;

[0015] When the average pressure of the first pressure measured by any adjacent pressure sensors is greater than a second preset value, the single battery is judged to be unqualified in the initial state;

[0016] When the average pressure of the first pressure measured by any adjacent pressure sensors is less than the second preset value, it is determined that the single battery is qualified in the initial state.

[0017] In some embodiments, some pressure sensors are arranged in a matrix, and the step of calculating the average pressure based on the first pressures measured by any adjacent pressure sensors includes:

[0018] Calculating an average pressure based on first pressures measured by adjacent pressure sensors located in the same row; and / or

[0019] An average pressure is calculated according to first pressures measured by adjacent pressure sensors located in the same column.

[0020] In some embodiments, after determining that the single battery is qualified in the initial state, the method further includes:

[0021] The pressing plate is further lowered so that the single cell is compressed from its designed thickness to a compressed thickness, which is the ideal thickness of the single cell when the fuel cell stack is pressed;

[0022] measuring, by means of a plurality of pressure sensors, a plurality of second pressures of the single battery when the battery is in any compression size during the compression process, where the compression size is smaller than the design thickness and larger than the compression thickness;

[0023] Whether the single battery is qualified when it is in any compressed size during the compression process is determined according to the multiple second pressures.

[0024] In some embodiments, the step of determining whether a single battery is qualified at any compression size during the compression process based on a plurality of second pressures includes:

[0025] When any second pressure does not meet the preset range value, it is determined that the single battery is unqualified when it is in the corresponding compressed size during the compression process;

[0026] When the plurality of second pressures are within the preset range, it is determined that the single battery is qualified when it is in the corresponding compressed size during the compression process.

[0027] In some embodiments, after determining that the battery cell is qualified at any compressed size during the compression process, the method further includes:

[0028] Continue to lower the pressing plate so that the single battery cell presents a target compression state, where the target compression state is the compression state of the single battery cell when the pressing plate is lowered to a target preset distance from the base plate, and the target preset distance is equal to the compressed thickness of the single battery cell;

[0029] measuring a plurality of third pressures between the pressure plate and the single battery cells by using a plurality of pressure sensors;

[0030] It is determined whether the single battery is qualified under the target compression state according to the plurality of third pressures.

[0031] In some embodiments, the step of determining whether the battery cell is qualified under the target compression state according to the plurality of third pressures includes:

[0032] determining a pressure mean and a pressure variance based on the plurality of third pressures;

[0033] When the pressure mean and the pressure variance meet the preset conditions, the single battery is judged to be qualified under the target compression state.

[0034] In a second aspect, the present application provides a method for preparing a fuel cell stack, comprising:

[0035] Providing a plurality of single cells that have passed the test according to the method of the first aspect;

[0036] Multiple single cells are stacked in sequence, and a preset pressure is applied to the stacked single cells to form a battery stack with a preset pressure.

[0037] In a third aspect, the present application provides a fuel cell comprising a fuel cell stack prepared by the method described in the second aspect.

[0038] After establishing a first preset spacing between the pressure plate and the base plate, the present invention uses multiple pressure sensors on the pressure plate to measure multiple first pressures between the plate and the individual cells. These multiple first pressures are used to determine whether the individual cells are qualified across their entire area. This allows for a more comprehensive assessment of whether the individual cells meet standards and avoids the phenomenon of unidentified local defects in individual cells. Furthermore, by continuously monitoring the thickness of the individual cells and the multiple second pressures between the measurement plate and the individual cells during the lowering of the pressure plate, defects in individual cells can be identified as quickly as possible, without having to wait for all tests to be completed before making a judgment, thereby improving detection efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0040] Figure 1 This is a schematic diagram of a scenario of a single cell battery testing system provided in an embodiment of the present application;

[0041] Figure 2 This is a flow chart of a single cell battery testing method provided in an embodiment of the present application;

[0042] Figure 3 This is a schematic diagram of a single cell pressure measurement provided in an embodiment of the present application;

[0043] Figure 4 is another schematic diagram of single cell pressure measurement provided in an embodiment of the present application;

[0044] Figure 5 This is a flow chart of determining whether a single battery is qualified during the compression process provided in an embodiment of the present application;

[0045] Figure 6 This is a flow chart of determining whether a single battery is qualified under a target compression state provided in an embodiment of the present application;

[0046] Figure 7 It is a flow chart of the method for preparing a battery stack provided in an embodiment of the present application. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0048] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot 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 said features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0049] In this application, the word "exemplary" is used to mean "serving as an example, illustration, or illustration." Any embodiment described in this application as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. The following description is given to enable any person skilled in the art to make and use the invention. In the following description, details are listed for the purpose of explanation. It should be understood that one of ordinary skill in the art will recognize that the invention can be practiced without these specific details. In other instances, well-known structures and processes are not described in detail to avoid obscuring the description of the invention with unnecessary detail. Therefore, the present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein.

[0050] The embodiments of the present application provide a single cell testing method, a method for preparing a battery stack, and a fuel cell, which are described in detail below.

[0051] First, see Figure 1 , Figure 1A schematic diagram of a single cell battery test system in an embodiment of the present application is shown. In the single cell battery test scenario, after a first preset distance is established between the pressure plate and the base plate, multiple pressure sensors on the pressure plate measure multiple first pressures between the plate and the single cell. The multiple first pressures can be used to determine whether the single cell is qualified over the entire area. Figure 1 As shown, the single cell battery testing system includes a server 101 , a single cell battery testing device 102 , a network 103 and a storage device 104 .

[0052] The server 101 can receive and / or process data and / or information from at least one component in the single cell battery test system or an external data source (e.g., the storage device 104 or the single cell battery test device 102). For example, the server 101 can receive pressure data detected by the pressure plate of the single cell battery test device 102; for another example, the server 101 can receive pressure data of the single cell battery sent by the storage device 104. In some embodiments of the present application, the server 101 can be a single server or a server group. In some embodiments of the present application, the server can be a host computer directly connected to the circuit breaker system, or a master station or remote server on a communication bus.

[0053] The single-cell battery testing device 102 can perform compression tests on single cells to determine whether they are qualified. The single-cell battery testing device 102 includes a base plate and a pressure plate. The base plate surface is used to mount the single cells. The pressure plate is equipped with multiple pressure sensors on the side facing the base plate. The pressure plate is raised and lowered to change the distance between it and the base plate to perform compression tests on the single cells. For example, the raising and lowering of the pressure plate can be achieved using a linear motion mechanism such as a pneumatic telescopic rod or a hydraulic telescopic rod.

[0054] The network 103 connects the various components in the single cell battery testing system so that the components can communicate with each other to facilitate the exchange of information and / or data. In some embodiments, at least one component in the single cell battery testing system (e.g., the server 101, the storage device 104, the single cell battery testing device 102) can send information and / or data (e.g., the first pressure, the second pressure, and the third pressure detected by the pressure sensor) to other components via the network 103. In some embodiments, the network between the various components in the single cell battery testing system can be any one or more of a wired network or a wireless network. For example, the network 103 can include a cable network, a wired network, a fiber optic network, a telecommunications network, an intranet, the Internet, a local area network, an in-device bus, an in-device line, a cable connection, etc., or any combination thereof.

[0055] The storage device 104 can store data and / or instructions. In some embodiments, the storage device 104 can store the first pressure, the second pressure, and the third pressure of the single cell obtained from the thickness detection sensor 102. For another example, the storage device 104 can store logs related to the single cell testing system. In some embodiments, the storage device 104 can store data and / or instructions that can be executed by the server 101. In some embodiments, the storage device 104 may include a large-capacity memory, a removable memory, a volatile read-write memory, a read-only memory (ROM), etc., or any combination thereof. Exemplarily, the large-capacity memory may include a magnetic disk, an optical disk, a solid-state disk, etc. In some embodiments, the storage device 104 can be implemented on a cloud platform.

[0056] It should be noted that the above description of the single-cell battery testing system is for illustrative purposes only and does not limit the scope of application of this application. Those skilled in the art will appreciate the guidance of this application and will be able to make various modifications and changes to the single-cell battery testing system. For example, a reminder device may be provided to alert personnel when a single cell is detected as unqualified.

[0057] Continue reading Figure 2 as well as Figure 3 , Figure 2 A schematic diagram of a process for testing a single cell battery in an embodiment of the present application is shown. Figure 3 A schematic diagram of a single cell pressure measurement in an embodiment of the present application is shown, wherein a single cell testing method is applied to a single cell testing device. The single cell testing device includes a pressing plate and a base plate arranged opposite to each other. A plurality of pressure sensors are arranged on the side of the pressing plate facing the base plate. The single cell testing method includes:

[0058] Step S201, installing single cells on a substrate;

[0059] Specifically, the substrate has a surface parallel to the horizontal plane, and the side of the pressure plate facing the substrate is parallel to the horizontal plane, so that after the pressure plate is lowered, it can fully contact the surface of the single cell and perform testing. In some embodiments of the present application, some pressure sensors on the side of the pressure plate facing the substrate are arranged in a matrix. Some of the pressure sensors in this matrix arrangement can correspond to the flow field areas of the single cell, so that the partial pressure sensors arranged in the matrix can comprehensively determine whether the flow field area of ​​the single cell is qualified. It is understandable that some pressure sensors are also located at the edge of the single cell to determine whether the edge area of ​​the single cell is qualified, thereby ensuring the sealing of adjacent single cells after the fuel cell stack is pressed.

[0060] The single cell includes an anode plate, a cathode plate and a membrane electrode that are combined with each other, wherein the anode plate and the cathode plate are made of a conductive material (such as metal or graphite), a hydrogen flow field is formed between the anode plate and the membrane electrode, and an air (or oxygen) flow field is formed between the cathode plate and the membrane electrode, and a sealing ring is also provided between the anode plate and the cathode plate, and between the cathode plate and the membrane electrode to seal the hydrogen flow field between the anode plate and the membrane electrode, and the oxygen flow field between the cathode plate and the membrane electrode. At the same time, in order to facilitate gas dispersion, both the anode plate and the cathode plate have arranged flow channels so that the reaction gas is evenly distributed on both sides of the membrane electrode while conducting electricity. Exemplarily, the flow channels of the anode plate and the cathode plate can be straight, serpentine or U-shaped flow channels.

[0061] The membrane electrode mainly includes a proton exchange membrane, an anode catalyst layer, a cathode catalyst layer, an anode gas diffusion layer, and a cathode gas diffusion layer. When hydrogen gas introduced into the anode plate reaches the anode catalyst layer through the anode gas diffusion layer, the hydrogen reacts after catalysis and produces hydrogen ions. The hydrogen ions pass through the proton exchange membrane and enter one side of the cathode plate, where they react with oxygen on the cathode side to form water, generating electricity during the above-mentioned redox reaction. For example, the proton exchange membrane can be a perfluorosulfonic acid membrane, a partially fluorinated polymer proton exchange membrane, a composite proton exchange membrane, or a non-fluorinated polymer proton exchange membrane.

[0062] Step S202: Lowering the pressing plate so that the single battery cell is in an initial state. The initial state is when the pressing plate is lowered to a first predetermined distance from the base plate, and the single battery cell is in contact with the pressing plate. The first predetermined distance is equal to the designed thickness of the single battery cell. The designed thickness is the ideal thickness of the single battery cell before compression when the surface is flat.

[0063] The design thickness of the single cell refers to the ideal thickness when the surface of the single cell is flat and not compressed. Since the first preset distance is equal to the design thickness of the single cell, the pressure plate can contact the surface of the single cell after it is lowered. At this time, the single cell is in its initial state.

[0064] It should be noted that if Figure 3 As shown, the pressure measurement points of the single cells correspond one-to-one to the pressure sensors on the pressure plate. The surface of the single cell can refer to the side of the cathode plate facing away from the membrane electrode, or the side of the anode plate facing away from the membrane electrode. The side of the anode plate or the cathode plate facing away from the membrane electrode usually has a flow field area and a distribution area. The distribution area is provided with a guide column structure, and the flow field area is provided with valleys and ridges that form flow channels. The pressure measurement points of the single cells can be located at the ridge of the flow channel, the guide column or the edge of the electrode plate. That is to say, when there is a first preset distance between the pressure plate and the substrate, the pressure plate can contact the ridge, the guide column or the edge of the electrode plate flow channel.

[0065] Step S203, measuring a plurality of first pressures between the pressure plate and the single battery cells by using a plurality of pressure sensors;

[0066] Since the surface of a single cell is not absolutely flat in actual situations and has some protrusions or depressions, multiple first pressures between the pressure plate and the single cell are measured by multiple pressure sensors. The first pressures can reflect the protrusion deformation of different pressure measurement points of the single cell. For example, when the protrusion deformation of a certain pressure measurement point on the surface of the single cell is greater, the first pressure is greater; conversely, when the protrusion deformation of a certain pressure measurement point on the surface of the single cell is smaller, the first pressure is smaller.

[0067] It can be understood that when the first pressure corresponding to a certain pressure measurement point of the single battery is equal to 0, it can be indicated that the pressure measurement point meets the size design requirements or has a concave situation.

[0068] Step S204 : judging whether the single battery is qualified in the initial state according to the multiple first pressures.

[0069] The initial state of a single cell refers to the state in which the cell has not been compressed to a thickness less than the designed thickness, that is, the state of the cell when a first preset distance exists between the pressure plate and the base plate. After obtaining multiple first pressures between the pressure plate and the cell, it can be determined whether the cell is qualified in the initial state. In some embodiments of the present application, when any one of the first pressures is greater than a first preset value, the cell can be determined to be unqualified in the initial state; when multiple first pressures are all less than the first preset value, the cell can be determined to be qualified in the initial state.

[0070] For example, the first preset value is 10N. When the first pressure corresponding to a certain pressure measurement point of the single cell is 12N, it can be judged that the single cell is unqualified in the initial state; when the first pressures corresponding to all pressure measurement points of the single cell are less than 10N, it can be judged that the single cell is qualified in the initial state.

[0071] In an embodiment of the present application, after a first preset distance is established between the pressure plate and the base plate, multiple pressure sensors on the pressure plate are used to respectively measure multiple first pressures between the plate and the single cells. The multiple first pressures are used to determine whether the single cells are qualified over the entire area. This can more comprehensively evaluate whether the single cells meet the standards and avoid the phenomenon of local defects of the single cells not being identified.

[0072] Due to the limited number of pressure sensors, when the pressure plate contacts the surface of the single cell, the pressure measurement points of the single cell do not completely correspond to the protrusions on the surface of the single cell. There may be a phenomenon where the protrusions are located between adjacent pressure measurement points. In order to more accurately determine whether the single cell is qualified in the initial state, in some other embodiments of the present application, the step of determining whether the single cell is qualified in the initial state based on multiple first pressures includes:

[0073] Calculating an average pressure based on first pressures measured by any adjacent pressure sensors;

[0074] When the average pressure of the first pressure measured by any adjacent pressure sensors is greater than a second preset value, the single battery is judged to be unqualified in the initial state;

[0075] When the average pressure of the first pressure measured by any adjacent pressure sensors is less than the second preset value, it is determined that the single battery is qualified in the initial state.

[0076] In the above embodiment, by calculating the average pressure of the first pressures measured by adjacent pressure sensors, when the protrusions on the surface of the single cell are located between adjacent pressure measurement points, the average pressure can better feedback the protrusion conditions on the surface of the single cell, and further, when the average pressure of the first pressures measured by any adjacent pressure sensors is greater than the second preset value, the single cell can be judged to be unqualified in the initial state; when the average pressure of the first pressures measured by any adjacent pressure sensors is less than the second preset value, the single cell can be judged to be qualified in the initial state, which is conducive to more accurately judging whether the single cell is qualified in the initial state.

[0077] In some embodiments of the present application, for example, for an embodiment of calculating an average pressure based on first pressures measured by any adjacent pressure sensors, see Figure 4 , Figure 4 A schematic diagram of single cell pressure measurement in an embodiment of the present application is shown. Some pressure sensors are arranged in a matrix. The step of calculating the average pressure based on the first pressure measured by any adjacent pressure sensors includes:

[0078] Calculating an average pressure based on first pressures measured by adjacent pressure sensors located in the same row; and / or

[0079] An average pressure is calculated according to first pressures measured by adjacent pressure sensors located in the same column.

[0080] It is understandable that the first pressures measured by four pressure sensors in two adjacent rows and two adjacent columns may be used to calculate the average pressure; or the pressure sensors may be arranged in other ways, such as a diamond arrangement.

[0081] Furthermore, after determining that the single battery is qualified in the initial state, in order to further test whether the single battery is qualified in the compressed state, continue to refer to Figure 5 , Figure 5 A schematic diagram of a process for determining whether a single battery is qualified during the compression process in an embodiment of the present application is shown, wherein the steps of determining whether a single battery is qualified during the compression process include:

[0082] Step S501, continuing to lower the pressing plate so that the single cell is compressed from the designed thickness to the compressed thickness, where the compressed thickness is the ideal thickness of the single cell when the fuel cell stack is compressed;

[0083] Step S502 , measuring, by means of a plurality of pressure sensors, a plurality of second pressures of the single battery cell when it is at any compression size during the compression process, where the compression size is smaller than the design thickness and larger than the compression thickness;

[0084] Step S503 : judging whether the single battery is qualified at any compression size during the compression process according to the plurality of second pressures.

[0085] After determining that the single cell is qualified in the initial state, the pressure plate can be lowered to compress the single cell to determine whether the single cell is qualified at any compressed dimension during the compression process. The compressed thickness of the single cell refers to the ideal thickness of the single cell when the fuel cell stack is compressed. During the compression process, the compressed dimension of the single cell compressed by the pressure plate is less than the design thickness but greater than the compressed thickness. For example, the design thickness of the single cell is 4mm, and its compressed thickness is 3mm. Any compressed dimension of the single cell during the compression process by the pressure plate is between 3mm and 4mm. For example, one compressed dimension of the single cell during the compression process by the pressure plate is 3.5mm.

[0086] In an embodiment of the present application, the measured second pressure may correspond to a concave state or a convex state of a certain pressure measurement point of the single cell. If a certain pressure measurement point is in a concave state, the second pressure is smaller. Conversely, if a certain pressure measurement point is in a convex state, the second pressure is larger. By judging the single cell based on the measured multiple second pressures, it is possible to identify whether there are uneven concave and convex phenomena on the surface of the single cell during the compression process, which is conducive to identifying hidden defects in the single cell.

[0087] In some embodiments of the present application, it is possible to determine whether each second pressure is within a preset range, thereby determining whether the battery is qualified at any compressed size during the compression process. For example, if each second pressure is within the preset range, the battery can be determined to be qualified at the corresponding compressed size; otherwise, the battery is determined to be unqualified.

[0088] In some embodiments of the present application, the step of determining whether a single battery is qualified at any compression size during the compression process according to a plurality of second pressures includes:

[0089] When any second pressure does not meet the preset range value, it is determined that the single battery is unqualified when it is in the corresponding compressed size during the compression process;

[0090] When the plurality of second pressures are within the preset range, it is determined that the single battery is qualified when it is in the corresponding compressed size during the compression process.

[0091] For example, the preset range value is 2.9Mpa to 3.1Mpa. When a certain second pressure detected is 3.2Mpa, it means that the pressure measurement point corresponding to the second pressure is convex, and it can be judged that the single battery is unqualified when it is in the corresponding compressed size during the compression process; when a certain second pressure detected is 2.8Mpa, it means that the pressure measurement point corresponding to the second pressure is concave, and it can be judged that the single battery is unqualified when it is in the corresponding compressed size during the compression process; when the second pressures corresponding to all pressure detection points are between 2.9Mpa and 3.1Mpa, it can be judged that the single battery is qualified when it is in the corresponding compressed size during the compression process.

[0092] It is understandable that the compression size can be set according to the test requirements, for example, the compression size can be set to 3.1mm, 3.2mm...3.9mm. When the single battery fails at any compression size during the compression process, subsequent testing can be stopped to simplify the testing process.

[0093] Furthermore, after confirming that the single cell is qualified at any compression size during the compression process, in order to further test whether the single cell is qualified in the stacked state, continue to refer to Figure 6 , Figure 6 A schematic diagram of a process for determining whether a single cell battery is qualified under a target compression state in an embodiment of the present application is shown, wherein the steps of determining whether a single cell battery is qualified under a target compression state include:

[0094] Step S601, continuing to lower the pressing plate so that the single battery cell is in a target compression state, where the target compression state is the compression state of the single battery cell when the pressing plate is lowered to a target preset distance from the base plate, where the target preset distance is equal to the compressed thickness of the single battery cell;

[0095] Step S602 , measuring a plurality of third pressures between the pressure plate and the single battery cells by using a plurality of pressure sensors;

[0096] Step S603 : judging whether the single battery is qualified under the target compression state according to the plurality of third pressures.

[0097] After determining that the individual cells are qualified at any compressed dimension during the compression process, the compression plate can be lowered to compress the individual cells to determine whether the individual cells are qualified at the target compression state. Since the target preset spacing is equal to the compressed thickness of the individual cells, that is, the thickness of the individual cells at this time is equal to the ideal thickness of the individual cells when the fuel cell stack is compressed, the target compression state of the individual cells is the state corresponding to the fuel cell stack when compressed. For example, if the compressed thickness of the individual cells is 3mm, the target preset spacing can be 3mm.

[0098] In an embodiment of the present application, multiple third pressures are used to judge the target compression state of the single cell, which is conducive to further identifying whether there are defects when the compression thickness of the single cell is at the compression thickness, so as to avoid hidden defects when the single cell is compressed to the compression thickness and cause the fuel cell stack to fail (such as leakage).

[0099] In some embodiments of the present application, each third pressure is determined to be within a preset range, thereby determining whether the battery is qualified under the target compression state. For example, if each third pressure is within the preset range, the battery can be determined to be qualified; otherwise, the battery is determined to be unqualified.

[0100] In some other embodiments of the present application, the step of determining whether a single battery is qualified under a target compression state includes:

[0101] determining a pressure mean and a pressure variance based on the plurality of third pressures;

[0102] When the pressure mean and the pressure variance meet the preset conditions, the single battery is judged to be qualified under the target compression state.

[0103] For example, the pressure mean is 4.1 MPa and the pressure variance is 5 MPa. 2 , when the preset conditions are that the mean pressure must be between 3.8Mpa and 4.2Mpa, and the pressure variance is 4Mpa 2 to 5Mpa 6 When the pressure mean is 4.3Mpa and the pressure variance is 7Mpa, the single cell can be judged to be qualified under the target compression state; otherwise, when the pressure mean is 4.3Mpa and the pressure variance is 7Mpa 2 , it can be judged that the single battery is unqualified.

[0104] It is worth noting that the above content on the single cell battery testing method is intended to clearly illustrate the implementation verification process of this application. Under the guidance of this application, those skilled in the art can also make equivalent modified designs. For example, according to the second pressure, the corresponding pressure mean and pressure variance are determined to determine whether the single cell battery is qualified at any compression size during the compression process.

[0105] Furthermore, in order to better implement the single cell testing method in the embodiment of the present application, based on the single cell testing method, the present application also provides a method for preparing a battery stack, see Figure 7 , Figure 7 A schematic flow chart of a method for preparing a battery stack in an embodiment of the present application is shown, wherein the method for preparing a battery stack includes:

[0106] Step S701, providing a plurality of single cells that have passed the test according to any of the above-mentioned methods;

[0107] Step S702 : stacking a plurality of single cells in sequence, and applying a preset pressure to the stacked single cells to form a battery stack having a preset pressure.

[0108] During the fuel cell stacking process, since each single cell has passed the test method, the surface deformation of the single cell, the deformation during the compression process, and the deformation after compression are known. After the defects corresponding to the single cell in the initial state, compression process, and target compression state are discovered and the unqualified single cells are eliminated, the reliability of the stack after multiple single cells are stacked can be guaranteed, avoiding the phenomenon of stack manufacturing failure due to defects in a single single cell.

[0109] Furthermore, to better implement the method for preparing the battery stack in the embodiments of this application, the present application also provides a fuel cell, which includes a battery stack prepared by the method described in any of the above embodiments. Because the fuel cell in the embodiments of this application includes the qualified single cells tested in the above embodiments, it has all the beneficial effects of the single cells in the above embodiments and will not be further described here.

[0110] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, please refer to the detailed description of other embodiments above and will not be repeated here.

[0111] The basic concepts have been described above. It will be apparent to those skilled in the art that the detailed disclosure above is merely illustrative and does not limit the present application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and amendments to the present application. Such modifications, improvements, and amendments are suggested in the present application and remain within the spirit and scope of the exemplary embodiments of the present application.

[0112] At the same time, this application uses specific terms to describe the embodiments of this application. For example, "one embodiment," "an embodiment," and / or "some embodiments" refer to a certain feature, structure, or characteristic related to at least one embodiment of this application. Therefore, it should be emphasized and noted that "one embodiment," "an embodiment," or "an alternative embodiment" mentioned twice or multiple times in different locations in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of this application may be appropriately combined.

[0113] Similarly, it should be noted that, in order to simplify the presentation of this application and thus facilitate understanding of one or more embodiments of the invention, the foregoing descriptions of the embodiments of this application sometimes combine multiple features into a single embodiment, figure, or description thereof. However, this disclosure method does not mean that the subject matter of this application requires more features than those recited in the claims. In fact, an embodiment may have fewer features than all of the features of a single embodiment disclosed above.

[0114] In some embodiments, numbers are used to describe the quantity of components and attributes. It should be understood that such numbers used in the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise stated, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the description and claims are approximate values, which may change according to the required features of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the general method of retaining digits. Although the numerical domains and parameters used to confirm the breadth of their range in some embodiments of the present application are approximate values, in specific embodiments, the settings of such numerical values ​​are as accurate as possible within the feasible range.

[0115] Each patent, patent application, patent application publication, and other materials, such as articles, books, specifications, publications, and documents, cited in this application is hereby incorporated by reference in its entirety, except for any application history that is inconsistent with or conflicts with this application, and excluding any document (currently or subsequently appended to this application) that limits the broadest scope of the claims of this application. It should be noted that if the descriptions, definitions, and / or terminology used in the accompanying materials are inconsistent with or conflict with the content of this application, the descriptions, definitions, and / or terminology used in this application will control.

[0116] The above is a detailed introduction to a single cell testing method, a stack preparation method and a fuel cell provided in the embodiments of the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for those skilled in the art, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A single cell battery testing method, characterized in that: The method is applied to a single-cell testing device, which includes a pressing plate and a substrate arranged opposite to each other, wherein a plurality of pressure sensors are arranged on a side of the pressing plate facing the substrate. The method includes: Installing single cells on the substrate; Lowering the pressing plate causes the single battery to assume an initial state, wherein the initial state is a state in which the single battery contacts the pressing plate when the pressing plate is lowered to a first preset distance from the base plate, wherein the first preset distance is equal to the designed thickness of the single battery, and the designed thickness is an ideal thickness of the single battery before the surface is flat and not compressed; measuring a plurality of first pressures between the pressure plate and the single cells by using the plurality of pressure sensors; determining whether the single battery is qualified in an initial state according to the plurality of first pressures; The method further comprises: Continuing to lower the pressing plate causes the single cells to present a target compression state, wherein the target compression state is the compression state of the single cells when the pressing plate is lowered to a target preset distance from the base plate, wherein the target preset distance is equal to the compressed thickness of the single cells, and the compressed thickness is the ideal thickness of the single cells when the fuel cell stack is compressed; measuring a plurality of third pressures between the pressure plate and the single cells by the plurality of pressure sensors; determining a pressure mean and a pressure variance based on the plurality of third pressures; When the pressure mean and the pressure variance meet preset conditions, it is determined that the single battery is qualified under the target compression state.

2. The single cell battery testing method according to claim 1, wherein: The step of judging whether the single battery is qualified according to the plurality of first pressures includes: When any of the first pressures is greater than a first preset value, it is determined that the single battery is unqualified in the initial state; When the plurality of first pressures are all less than a first preset value, it is determined that the single battery is qualified in the initial state.

3. The single cell battery testing method according to claim 1, wherein: The step of judging whether the single battery is qualified in the initial state according to the multiple first pressures includes: Calculating an average pressure based on first pressures measured by any adjacent pressure sensors; When the average pressure of the first pressure measured by any adjacent pressure sensors is greater than a second preset value, it is determined that the single battery is unqualified in the initial state; When the average pressure of the first pressure measured by any adjacent pressure sensors is less than the second preset value, it is determined that the single battery is qualified in the initial state.

4. The single cell battery testing method according to claim 3, wherein: Some of the pressure sensors are arranged in a matrix, and the step of calculating the average pressure based on the first pressures measured by any adjacent pressure sensors includes: Calculating an average pressure based on first pressures measured by adjacent pressure sensors located in the same row; and / or An average pressure is calculated according to first pressures measured by adjacent pressure sensors located in the same column.

5. The single cell battery testing method according to claim 2 or 3, wherein: After determining that the single battery is qualified in the initial state, the method further includes: Continue to lower the pressing plate so that the single battery is compressed from the designed thickness to the compressed thickness; measuring, by the multiple pressure sensors, multiple second pressures of the single battery when it is in any compression size during the compression process, where the compression size is smaller than the designed thickness and larger than the compression thickness; Whether the single battery is qualified when it is in any compressed size during the compression process is determined according to the multiple second pressures.

6. The single cell battery testing method according to claim 5, wherein: The step of judging whether the single battery is qualified at any compression size during the compression process according to the plurality of second pressures includes: When any of the second pressures does not meet the preset range, it is determined that the single battery is unqualified when it is in the corresponding compressed size during the compression process; When the plurality of second pressures are all within a preset range, it is determined that the single battery is qualified when it is in the corresponding compressed size during the compression process.

7. A method for preparing a fuel cell stack, characterized in that: include: Providing a plurality of single cells that have passed the test of the single cell testing method according to any one of claims 1 to 6; A plurality of the single cells are stacked in sequence, and a preset pressure is applied to the stacked single cells to form a battery stack with a preset pressure.

8. A fuel cell, characterized in that: Including a fuel cell stack prepared by the preparation method as claimed in claim 7.

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