Fuel cell single cell shaping method and apparatus

Abstract

The application provides a single cell shaping method and device of a fuel cell. The method is performed by a shaping device. The shaping device comprises a first upper tool and a first lower tool arranged oppositely. The surface of the first upper tool close to one side of the first lower tool is a flat surface. The surface of the first lower tool close to one side of the first upper tool is a flat surface. The method comprises: preheating the single cell in a free state and / or the shaping device, placing the single cell into the shaping device when the preheating reaches a first temperature, the first surface of the single cell being in contact with the first upper tool, and the second surface being in contact with the first lower tool; maintaining the single cell and the shaping device at the first temperature for a first preset time period, and applying a shaping force to the single cell until the single cell shaping is completed; and performing a cooling process after the first preset time period, and completing the shaping when a second temperature is reached. The application applies a shaping force to the single cell for sufficient shaping, and controls the shaping temperature to avoid the extrusion and overflow of hot melt adhesive film.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a method and apparatus for shaping a single cell of a fuel cell. Background Technology

[0002] A single cell is an independent power generation unit formed by bonding an anode single plate, a membrane electrode, and a cathode single plate together with a film through hot pressing. Because the structure of a single cell is not an absolutely symmetrical structure, and the shrinkage of the plates, membrane electrodes, and film during the cooling process is inconsistent, and the influence of factors such as hot pressing process parameters, stress concentration occurs inside the single cell, which in turn causes the single cell to warp.

[0003] After hot pressing, individual cells exhibit significant warping deformation due to internal stress. This warping deformation affects the contact state of the fuel cell stack assembly, causing localized stress concentration, increasing stacking deviations, and impacting the distribution of water and gas within the cell, thus affecting the fuel cell stack performance. Therefore, it is necessary to perform thermal shaping on individual cells to release internal stress, improve the flatness of the cells, thereby improving the contact state of the fuel cell stack, reducing assembly deviations, and enhancing the uniformity of water and gas distribution within the stack.

[0004] In existing technologies, the residual heat after hot pressing of a single cell is typically used to shape it. This shaping process requires vacuuming to remove some heat and improve contact heat transfer. The patent describes introducing a cooling medium to the pressing unit and the supporting unit for cooling. While this patented method allows the single cell to enter a natural cooling phase after hot pressing, the temperature fluctuations during this phase are large and uncontrollable, affecting the thermal shaping effect. Alternatively, existing technologies use pressing components and temperature regulation structures for bipolar plate bonding and shaping. The patent uses a temperature regulation structure for temperature control, including both heating and cooling. The core purpose of heating is to soften the plates so they can be flattened, improving adhesion. However, it does not address the issue of adhesive film deformation. Summary of the Invention

[0005] The purpose of this application is to provide a method and apparatus for shaping a single cell of a fuel cell, which can apply a shaping force to the single cell to fully shape it, and avoid the problems of hot melt adhesive film extrusion and overflow by controlling the shaping temperature.

[0006] On one hand, one embodiment of this application provides a method for shaping a single cell of a fuel cell. The method is performed by a shaping device, which includes a first upper fixture and a first lower fixture. The first upper fixture and the first lower fixture are disposed opposite to each other. The surface of the first upper fixture near the first lower fixture is a flat surface, and the surface of the first lower fixture near the first upper fixture is also a flat surface. The method includes:

[0007] Preheating of the single cell and / or preheating of the shaping device, wherein the single cell and the shaping device are in a free state;

[0008] When the temperature is preheated to the first temperature, the single cell is placed in the shaping device, wherein the first surface of the single cell is in contact with the first upper tooling and the second surface of the single cell is in contact with the first lower tooling.

[0009] During a first preset time period, the single battery and the shaping device are kept at a first temperature, and a shaping force is applied to the single battery through the shaping device.

[0010] After the first preset time period ends, the single cell and the shaping device are cooled down. Once the second temperature is reached, the shaping of the single cell is completed. The shaping device applies a shaping force to the single cell until the shaping is complete.

[0011] In one embodiment, the shaping device further includes: a second upper tooling and a second lower tooling disposed opposite to each other, wherein a first region of the first upper tooling has a first groove, the second upper tooling is embedded in the first groove, and the thickness of the second upper tooling is less than the depth of the first groove; and a second region of the first lower tooling has a second groove, the second lower tooling is embedded in the second groove of the first lower tooling, and the thickness of the second lower tooling is less than the depth of the second groove.

[0012] Placing a single cell into the shaping device includes: the reaction distribution area of ​​the single cell contacting the inner surfaces of the second upper tooling and the second lower tooling; the adhesive film bonding area of ​​the single cell contacting the third area of ​​the first upper tooling and the fourth area of ​​the first lower tooling; the third area is located on both sides of the first area, and the fourth area is located on both sides of the second area.

[0013] Applying a shaping force to a single cell using a shaping device includes: applying a first leveling force to the reaction zone and distribution zone of the single cell using a second upper tooling, and applying a second leveling force to the adhesive film bonding zone of the single cell using the first upper tooling; wherein the shaping force is the sum of the first leveling force and the second leveling force.

[0014] In one embodiment, the first leveling force is calculated based on the surface pressure when multiple single cells are assembled to form a stack, combined with the area of ​​the reaction distribution region of the single cell; the second leveling force is obtained based on the leveling force curve of the adhesive film bonding region.

[0015] In one embodiment, the first temperature is 5-10°C above the softening point of the single cell; the first preset time period is less than or equal to 1 minute; when cooling the single cell and the shaping device, the cooling rate of the single cell and the shaping device is controlled to be less than or equal to 5°C / min.

[0016] In one embodiment, the ambient humidity of the single battery and the shaping device is controlled within the range of 40%-80% throughout the entire thermal shaping process.

[0017] In one embodiment, before preheating the single battery and / or preheating the shaping device, the method further includes: placing the single battery on a measuring platform and measuring a first warpage value of the single battery; comparing the measured first warpage value with a qualified value to determine whether the first warpage value is less than or equal to the qualified value; if so, then no shaping is required for the single battery; if not, then shaping is required for the single battery.

[0018] In one embodiment, after the single cell is shaped, the method further includes: placing the shaped single cell on a measuring platform and measuring the second warpage value of the shaped single cell; comparing the second warpage value with the qualified value to determine whether the second warpage value is less than or equal to the qualified value; if so, the shaping is ended; if not, the shaped single cell is shaped again until the single cell reaches the qualified value.

[0019] On the other hand, in one embodiment, this application also provides a single-cell shaping device for a fuel cell, which is applied to the single-cell shaping method for a fuel cell in any of the above embodiments, including: a first upper tooling and a first lower tooling, wherein the inner surface of the first upper tooling corresponds to the inner surface of the first lower tooling and both are flat surfaces; a second upper tooling and a second lower tooling, wherein the inner surface of the second upper tooling corresponds to the inner surface of the second lower tooling and both are flat surfaces;

[0020] The first upper tooling has a first groove in its first region, and the second upper tooling is embedded in the first groove, with the thickness of the second upper tooling being less than the depth of the first groove; the first lower tooling has a second groove in its second region, and the second lower tooling is embedded in the second groove of the first lower tooling, with the thickness of the second lower tooling being less than the depth of the second groove.

[0021] In one embodiment, the shaping device further includes at least one limiting block located between the first upper tooling and the first lower tooling, the limiting block being used to limit the downward pressing height of the shaping device.

[0022] In one embodiment, the shaping device further includes: at least two first positioning grooves disposed in a third region of a first upper tooling; at least two second positioning grooves disposed in a fourth region of a first lower tooling; the second positioning grooves correspond one-to-one with the first positioning grooves; and at least two positioning members that position the first upper tooling and the first lower tooling through the first positioning grooves and the second positioning grooves; wherein the third region is located on both sides of the first region, and the fourth region is located on both sides of the second region.

[0023] The advantages of this application compared to the prior art are:

[0024] This application preheats a single cell and / or a shaping device in a free state. When the preheated temperature reaches a first temperature, the single cell is placed in the shaping device. For a first preset time period, the single cell and the shaping device are kept at the first temperature, and a shaping force is applied to the single cell until shaping is complete. After the first preset time period ends, the single cell and the shaping device are cooled down until a second temperature is reached, completing the shaping process. This application achieves sufficient shaping by applying a shaping force to the single cell and controls the shaping temperature to avoid problems such as extrusion and overflow of the hot melt adhesive film. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of a first structure of a shaping device according to an embodiment of this application;

[0027] Figure 2 This is a schematic diagram of a single-cell structure of a fuel cell according to an embodiment of this application;

[0028] Figure 3 This is a schematic diagram of a second structure of the shaping device according to an embodiment of this application;

[0029] Figure 4 This is a schematic diagram illustrating the steps of a shaping method according to an embodiment of this application;

[0030] Figure 5 This application provides a schematic diagram of the temperature and pressure curves during the single-cell shaping process, illustrating one embodiment of the present application.

[0031] Figure 6 This is a schematic diagram illustrating the steps of a second shaping method according to an embodiment of this application;

[0032] Figure 7 As shown in one embodiment of this application Figure 3 A magnified schematic diagram of part A;

[0033] Figure 8 This is a schematic diagram of the leveling force curve of the adhesive film bonding area shown in an embodiment of this application;

[0034] Figure 9 This is a schematic diagram illustrating steps preceding execution step S410, as shown in an embodiment of this application.

[0035] Figure 10 This is a schematic diagram illustrating a single-cell warpage evaluation method according to an embodiment of this application;

[0036] Figure 11 As shown in one embodiment of this application Figure 9 It includes a schematic diagram of the steps following step S430.

[0037] The above figures include the following reference numerals:

[0038] 1-Single cell; 2-Reaction distribution area; 3-Film bonding area; 4-Shaping device; 5-First upper fixture; 6-First lower fixture; 7-Second upper fixture; 8-Second lower fixture; 9-First region; 10-Second region; 11-Third region; 12-Fourth region; 13-First positioning groove; 14-Second positioning groove; 15-Positioning component; 16-Membrane electrode; 17-Anode plate; 18-Anode film; 19-Anode frame; 20-Cathode frame; 21-Cathode film; 22-Cathode plate; 23-Anode plate flow channel; 24-Anode GDL; 25-Cathode GDL; 26-Cathode plate flow channel; 27-Third surface; 28-Fourth surface; 29-Fifth surface; 30-Sixth surface. Detailed Implementation

[0039] The terms “first,” “second,” “third,” etc., are used only for distinguishing descriptions and do not indicate a sequence number, nor should they be interpreted as indicating or implying relative importance.

[0040] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0041] In the description of this application, it should be noted that the terms "inner", "outer", "left", "right", "upper", "lower", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this application is in use. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0042] In the description of this application, unless otherwise expressly specified and limited, the terms “set up,” “install,” “connect,” and “link” shall be interpreted broadly, for example, as a fixed connection, a detachable connection, or an integral connection; as a mechanical connection or an electrical connection; as a direct connection or an indirect connection through an intermediate medium; or as a connection within two components.

[0043] During the hot-pressing process, a high-temperature, high-pressure method is used to achieve full wetting and bonding of the cell adhesive film. To ensure bonding efficiency, rapid cooling is usually employed. This combination of high temperature, high pressure, and rapid cooling leads to significant warping of the cell. Therefore, to flatten the cell, improve the contact condition of the fuel cell stack, reduce assembly deviations, and enhance the uniformity of moisture distribution within the stack, cell reshaping is necessary.

[0044] This application provides a single-cell shaping device for a fuel cell and a single-cell shaping method for a fuel cell. Figure 1 This is a schematic diagram of a first structure of a shaping device according to an embodiment of this application, as shown below. Figure 1 As shown, the shaping device includes a first upper fixture 5 and a first lower fixture 6; wherein the inner surface of the first upper fixture 5 corresponds to the inner surface of the first lower fixture 6 and both are flat surfaces. During the shaping process, a single battery 1 is placed between the first upper fixture 5 and the first lower fixture 6, with the first surface (i.e., the upper surface) of the single battery 1 in contact with the first upper fixture 5 and the second surface (i.e., the lower surface) of the single battery 1 in contact with the first lower fixture 6. A shaping force is applied to the single battery 1 through the first upper fixture 5 and the first lower fixture 6 for shaping. The shaping device 4 uses a high thermal conductivity material for rapid heat conduction; the high thermal conductivity material can be copper, etc.

[0045] In another embodiment, Figure 2 This is a schematic diagram of a single-cell structure of a fuel cell according to an embodiment of this application. Figure 3 This is a schematic diagram of a second structure of the shaping device according to an embodiment of this application, as shown below. Figure 2-3 As shown, the single cell 1 includes a reaction distribution region 2 and a film bonding region 3. The shaping device 4 includes: a first upper tooling 5, a first lower tooling 6, a second upper tooling 7, and a second lower tooling 8; wherein the inner surface of the first upper tooling 5 corresponds to the inner surface of the first lower tooling 6 and both are flat surfaces; the inner surface of the second upper tooling 7 corresponds to the inner surface of the second lower tooling 8 and both are flat surfaces. The first upper tooling 5 includes a first region 9, which has a first groove, and the second upper tooling 7 is embedded in the first groove, with the thickness of the second upper tooling 7 being less than the depth of the first groove; the first lower tooling 6 includes a second region 10, which has a second groove, and the second lower tooling 8 is embedded in the second groove of the first lower tooling 6, with the thickness of the second lower tooling 8 being less than the depth of the second groove. The first upper tooling 5 also includes a third region 11, located on both sides of the first region 9, and the first lower tooling 6 also includes a fourth region 12, located on both sides of the second region 10.

[0046] During the shaping process, the reaction distribution area 2 of the single cell 1 is brought into contact with the inner surfaces of the second upper tooling 7 and the second lower tooling 8, and the adhesive film bonding area 3 of the single cell 1 is brought into contact with the third region 11 of the first upper tooling 5 and the fourth region 12 of the first lower tooling 6; a first leveling force is applied to the reaction distribution area 2 by the second upper tooling 7 and the second lower tooling 8, and a second leveling force is applied to the adhesive film bonding area 3 of the single cell 1 by the third region 11 of the first upper tooling 5 and the fourth region 12 of the first lower tooling 6.

[0047] In one embodiment, the shaping device 4 further includes at least one limiting block (not shown in the figure), located between the first upper tooling 5 and the first lower tooling 6. The limiting block limits the downward pressure height of the shaping device 4, preventing the first upper tooling 5 and the second upper tooling 7 from getting too close to the first lower tooling 6 and the second lower tooling 8, thus preventing damage to the single battery 1. When the first upper tooling 5 and the second upper tooling 7 move a preset distance relative to the first lower tooling 6 and the second lower tooling 8, the limiting block prevents the first upper tooling 5 and the second upper tooling 7 from getting any closer to the first lower tooling 6 and the second lower tooling 8. The preset distance can be set by the user.

[0048] Furthermore, the limiting block can be a protrusion provided in the third region 11 of the first upper tooling 5, and a corresponding groove provided in the fourth region 12 of the first lower tooling 6; or the limiting block can be a protrusion provided in the fourth region 12 of the first lower tooling 6, and a corresponding groove provided in the third region 11 of the first upper tooling 5; or grooves can be provided in the third region 11 of the first upper tooling 5 and the fourth region 12 of the first lower tooling 6 respectively. When using the shaping device 4, the limiting block is placed in the corresponding groove in the fourth region 12 of the first lower tooling 6, and then the first upper tooling 5 and the first lower tooling 6 are installed by the cooperation of the limiting block and the groove in the third region 11.

[0049] In one embodiment, the shaping device 4 further includes: at least two first positioning grooves 13, at least two second positioning grooves 14, and at least two positioning elements 15; wherein, the second positioning grooves 14 correspond one-to-one with the first positioning grooves 13; the first positioning grooves 13 are disposed in the third region 11 of the first upper tooling 5; the second positioning grooves 14 are disposed in the fourth region 12 of the first lower tooling 6; the positioning elements 15 position the first upper tooling 5 and the first lower tooling 6 through the first positioning grooves 13 and the second positioning grooves 14.

[0050] In one embodiment, this application also provides a method for shaping a single cell of a fuel cell, the method being performed using the aforementioned shaping device 4. Figure 4 This is a schematic diagram illustrating the steps of a shaping method according to an embodiment of this application. When using... Figure 1 When the first structure of the single-cell shaping device shown shapes a single cell, such as... Figure 1 and Figure 4As shown, the method includes:

[0051] Step S410: Preheat the single cell 1 and / or preheat the shaping device 4, wherein the single cell 1 and the shaping device 4 are in a free state.

[0052] In this process, preheating is performed in a free state, which can fully release internal stress and soften the film. At the same time, the shaping fixture can also be preheated. When the single cell 1 and the shaping fixture are preheated to the same temperature, the shaping effect can be improved.

[0053] Step S420: When preheated to the first temperature, the single battery 1 is placed in the shaping device 4. During the first preset time period, the single battery 1 and the shaping device 4 are kept warm at the first temperature, and a shaping force is applied to the single battery 1 through the shaping device 4.

[0054] After reaching the first temperature, the battery is kept warm. At the same time, the first surface of the single battery 1 is brought into contact with the first upper tooling 5, and the second surface of the single battery 1 is brought into contact with the first lower tooling 6. The first upper tooling 5 and the second lower tooling 8 of the shaping device 4 apply a shaping force to the battery to make the film uniformly distributed. The shaping force is a fixed value. The first temperature can be set by the user.

[0055] Step S430: After the first preset time period ends, the single battery 1 and the shaping device 4 are cooled down. After the second temperature is reached, the shaping of the single battery 1 is completed. The shaping device 4 applies a shaping force to the single battery 1 until the shaping of the single battery 1 is completed.

[0056] In this process, the single battery 1 and the shaping device 4 are slowly cooled to reach the second temperature, the adhesive film is re-cured, the pressure is released after reaching the second temperature, the shaping of the single battery 1 is completed, and the shaped single battery 1 is taken out; the shaping force is a fixed value; the second temperature can be set by the user or is the room temperature of the environment in which the single battery 1 and the shaping device 4 were placed before preheating; the first preset time period can be set by the user.

[0057] Figure 5 This application provides a schematic diagram illustrating the temperature and pressure curves during the single-cell shaping process, as shown in the embodiment of the present application. Figure 5As shown, in the preheating stage of single cell 1, considering the thermal properties of the hot melt adhesive film, single cell 1 is preheated to 5-10°C above its softening point. This ensures the film softens sufficiently while preventing excessive fluidity and adhesive overflow during the shaping process. In the heat preservation stage of single cell 1, the main function is to ensure uniform temperature distribution within the cell. Since single cell 1 has a thin-walled structure and conducts heat quickly, this stage is controlled to last ≤1 minute. In the slow cooling stage of single cell 1, the cooling rate needs to be controlled to ≤5°C / min to prevent rapid shrinkage of the film after rapid cooling, eliminate residual stress, and avoid stress concentration caused by rapid cooling, thus achieving the shaping of single cell 1. Specifically, the first temperature is 5-10°C above the softening point of single cell 1; the first preset time period is ≤1 minute; and when cooling single cell 1 and shaping device 4, the cooling rate of both is controlled to be ≤5°C / min.

[0058] Specifically, the single cell 1 and / or the shaping device 4 in a free state are preheated at the second temperature. When the preheating reaches the first temperature (5-10°C above the softening point of the single cell 1), the single cell 1 is transferred into the shaping device 4, and a shaping force is applied to both the single cell 1 and the shaping device 4. The single cell 1 and the shaping device 4 are kept warm for a first preset time period (t1-t2), wherein the first preset time period is less than or equal to 1 minute. After the first preset time period ends, the single cell 1 and the shaping device 4 are slowly cooled down, and the cooling rate of the single cell 1 and the shaping device 4 is controlled to be less than or equal to 5°C / min. After the temperature of the single cell 1 and the shaping device 4 reaches the second temperature, the shaping of the single cell 1 is completed. The second temperature is the room temperature of the environment in which the single cell 1 and the shaping device 4 are located.

[0059] The shaping method provided in this application includes: preheating the single cell 1 in a free state to fully release its internal stress; and a slow cooling process after the first preset time period to allow the adhesive film to solidify slowly, avoiding rapid cooling and shrinkage of the adhesive film and improving the shaping effect of the single cell 1; while preheating to the first temperature, maintaining temperature and pressure during the shaping of the single cell 1 to make the thickness distribution of the adhesive film more uniform and improve the bonding quality of the single cell 1. Furthermore, accurate temperature control during the shaping process prevents the extrusion of the hot melt adhesive film during the shaping process; and the shaping process of the single cell 1 in this application simulates the assembly state of the single cell 1 in the battery stack, which can improve the shaping effect and the contact state of the battery in the battery stack assembly.

[0060] In one embodiment, Figure 6 This is a schematic diagram illustrating the steps of a second shaping method according to an embodiment of this application. When using Figure 3 When the second structure of the shaping device shown shapes a single cell, such as Figure 2-6As shown, step S420 includes:

[0061] Step S421: The reaction distribution area 2 of the single cell 1 is brought into contact with the inner surfaces of the second upper tooling 7 and the second lower tooling 8, and the adhesive film bonding area 3 of the single cell 1 is brought into contact with the third area 11 of the first upper tooling 5 and the fourth area 12 of the first lower tooling 6.

[0062] Furthermore, Figure 7 As shown in one embodiment of this application Figure 3 An enlarged schematic diagram of part A, as shown below. Figure 2-7 As shown, to prevent damage to the Catalyst Coated Membrane (CCM) 16 during the shaping process of the single cell 1 due to twisting or stretching, and to ensure the flatness and alignment of the CCM 16 during the pressure shaping process, the single cell 1 needs to be shaped using the CCM 16 as a reference. To ensure that the CCM 16 is always used as the reference line during the shaping process, the thickness of the second upper tooling 7 is less than the depth of the first groove; the thickness of the second lower tooling 8 is less than the depth of the second groove. That is, the surface of the first upper tooling 5 that contacts the adhesive film bonding area 3 is set as the third surface 27. The surface of the upper tooling 7 that contacts the reaction distribution area 2 is designated as the fourth surface 28. A first height difference H12 is set between the third surface 27 and the fourth surface 28. The surface of the first lower tooling 6 that contacts the adhesive film bonding area 3 is designated as the fifth surface 29. The surface of the second lower tooling 8 that contacts the reaction distribution area 2 is designated as the sixth surface 30. A second height difference H13 is set between the fifth surface 29 and the sixth surface 30. That is, by setting the first height difference H12 and the second height difference H13, the shaping is ensured with the membrane electrode 16 as the reference line.

[0063] like Figure 7 As shown, in the bonding area, above the reference line film electrode 16 are the anode plate 17, anode adhesive film 18, and anode frame 19 of the single cell 1; below the reference line film electrode 16 are the cathode frame 20, cathode adhesive film 21, and cathode plate 22. In the reaction distribution area 2, above the reference line film electrode 16 are the anode plate channel 23 and the anode GDL 24 (Gas Diffusion Layer); below the reference line film electrode 16 are the cathode GDL 25 (Gas Diffusion Layer) and the cathode plate channel 26. The first height difference H12 and the second height difference H13 are calculated using the following formulas:

[0064] H12 = H7 + H8 * (anode GDL24 compression ratio) + H9 - H1 - H2 - H3; (1)

[0065] H13 = H11 + H10 * (cathode GDL25 compression ratio) - H4 - H5 - H6; (2)

[0066] Wherein, H1 is the anode plate 17 of single cell 1, H2 is the anode gel film 18, H3 is the anode frame 19, H4 is the cathode frame 20, H5 is the cathode gel film 21, H6 is the cathode plate 22, H7 is the anode plate flow channel 23, H8 is the anode GDL 24, H9 is the membrane electrode 16, H10 is the cathode GDL 25, and H11 is the cathode plate flow channel 26.

[0067] Step S422: Apply a first leveling force to the reaction zone and distribution zone of the single cell 1 through the second upper tooling 7, and apply a second leveling force to the adhesive film bonding zone 3 of the single cell 1 through the first upper tooling 5; wherein, the leveling force is the sum of the first leveling force and the second leveling force.

[0068] Specifically, the first leveling force is calculated based on the surface pressure when multiple individual cells 1 are assembled to form a stack, combined with the area of ​​the reaction distribution region 2 of the individual cell 1. The specific formula is as follows:

[0069] F1 = P * S; (3)

[0070] Where F1 is the first leveling force, P is the surface pressure of the stack formed by the single cell 1 in the assembled state, and S is the area of ​​the reaction distribution region 2 of the single cell 1.

[0071] Specifically, Figure 8 This is a schematic diagram of the leveling force curve of the adhesive film bonding area shown in an embodiment of this application, as follows: Figure 7 As shown, the second leveling force is obtained from the leveling force curve of the adhesive film bonding area.

[0072] Specifically, the second leveling force F2 in the bonding area is calibrated by adjusting the leveling force in the bonding area of ​​single cell 1. The calibrated leveling displacement versus leveling force curve is shown below. Figure 7 As shown, when the leveling displacement is less than S1, the generated force is the leveling force to overcome the warping of the bonding area of ​​single cell 1. When the leveling displacement is greater than S1, the generated force is the elastic deformation force to overcome the bonding area. This part is approximately a straight line. The method for determining F2 is as follows: the vertical coordinate of the intersection point of the tangent line overcoming the elastic deformation force of the bonding area and the curve overcoming the leveling force overcoming the warping of the bonding area of ​​single cell 1 is the leveling force F2 of the bonding area; S1 is the horizontal coordinate of the intersection point of the tangent line overcoming the elastic deformation force of the bonding area and the curve overcoming the leveling force overcoming the warping of the bonding area of ​​single cell 1.

[0073] In one embodiment, the ambient humidity of the single cell 1 and the shaping device 4 is controlled within the range of 40%-80%. During the thermal shaping process, as the shaping temperature rises, the membrane electrode 16 gradually loses water and warps, increasing the internal stress of the single cell 1 and affecting the shaping quality of the battery. Simultaneously, the water loss and warping of the membrane electrode 16 increases the risk of leakage or even breakage. Therefore, during the thermal shaping of the single cell 1, it is necessary to control the process humidity within the range of 40-80% to ensure that the membrane electrode 16 is thermally shaped under relatively humid conditions, thus preventing water loss and warping.

[0074] In one embodiment, Figure 9 This is a schematic diagram illustrating steps preceding execution step S410, as shown in an embodiment of this application. Figure 9 As shown, the procedure before performing step S410 also includes:

[0075] Step S910: Place the single cell 1 on the measurement platform and measure the first warpage value of the single cell 1.

[0076] in, Figure 10 This is a schematic diagram illustrating a warpage evaluation method for a single cell 1 according to an embodiment of this application, as shown below. Figure 10 As shown, a single battery 1 is placed on a measuring platform, and the height H of the maximum bulge of the single battery 1 to the measuring platform is measured, which is taken as the first warpage value of the single battery 1.

[0077] Step S920: Compare the measured first warpage value with the qualified value to determine whether the first warpage value is less than or equal to the qualified value; wherein, the qualified value can be a value defined by the user.

[0078] Step S930: If so, then there is no need to reshape the single cell 1.

[0079] Step S940: If not, then single cell 1 needs to be shaped.

[0080] In one embodiment, Figure 11 As shown in one embodiment of this application Figure 9 It includes a diagram of the steps following step S430, such as... Figure 11 As shown, after the single cell 1 is shaped in step S430, the process further includes:

[0081] Step S1110: Place the shaped single cell 1 on the measuring platform and measure the second warpage value of the shaped single cell 1.

[0082] Similarly, the shaped single cell 1 is placed on the measurement platform, and the height of the maximum bulge of the shaped single cell 1 to the measurement platform is measured, which is taken as the second warp value of the single cell 1.

[0083] Step S1120: Compare the second warping value with the qualified value to determine whether the second warping value is less than or equal to the qualified value; wherein, the qualified value can be a value defined by the user.

[0084] Step S1130: If yes, then end the procedure.

[0085] Step S1140: If not, reshape the single cell 1 after shaping until the single cell 1 reaches the qualified value.

[0086] In one embodiment, as shown in Table 1 below, the acceptable value for a single battery 1 is set to 4mm. The measured first warpage value (value before shaping) is compared with the acceptable value to determine whether the first warpage value (value before shaping) is less than or equal to the acceptable value of 4mm. If yes, no shaping is required for the single battery 1; otherwise, shaping is required. In Table 1, the first warpage value of battery 3 is less than or equal to the acceptable value of 4mm, so no shaping is required, and battery 3 does not have a warpage improvement ratio. Therefore, the value after shaping and the warpage improvement ratio are not filled in the table. The first warpage values ​​of batteries 1, 2, and 4 are greater than the acceptable value of 4mm, so shaping is required. After shaping, the warpage improvement ratio of batteries 1, 2, and 4 is calculated. The ratio of the difference between the value before shaping (first warpage value) and the value after shaping (second warpage value) to the value before shaping (first warpage value) is the warpage improvement ratio. As shown in Table 1, the warpage of the single cell 1 can be significantly improved by using the method and apparatus of this application to shape the single cell 1.

[0087] Table 1. Data on the improvement rate of warpage before and after single-cell reshaping

[0088]

[0089] It should be noted that, where there is no conflict, the features in the embodiments of this application can be combined with each other. The above are merely preferred embodiments of this application and are not intended to limit this application. For those skilled in the art, this application can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for shaping a single cell of a fuel cell, characterized in that, The method is performed by a shaping device, which includes a first upper fixture and a first lower fixture. The first upper fixture and the first lower fixture are arranged opposite to each other. The surface of the first upper fixture near the first lower fixture is a flat surface, and the surface of the first lower fixture near the first upper fixture is also a flat surface. The method comprises: a second upper tooling and a second lower tooling are provided relative to each other; the first upper tooling has a first groove in a first region, and the second upper tooling is embedded in the first groove, the thickness of the second upper tooling being less than the depth of the first groove; the first lower tooling has a second groove in a second region, and the second lower tooling is embedded in the second groove of the first lower tooling, the thickness of the second lower tooling being less than the depth of the second groove; the method includes: The single cell is preheated and / or the shaping device is preheated, wherein the single cell and the shaping device are in a free state; When preheated to the first temperature, a single cell is placed in the shaping device, wherein the first surface of the single cell is in contact with the first upper tooling and the second surface of the single cell is in contact with the first lower tooling. During a first preset time period, the single battery and the shaping device are kept warm at a first temperature, and a shaping force is applied to the single battery through the shaping device. After the first preset time period ends, the single battery and the shaping device are cooled down. After the second temperature is reached, the shaping of the single battery is completed. The shaping device applies a shaping force to the single battery until the shaping of the single battery is completed. The step of placing a single battery into the shaping device includes: The reaction distribution area of ​​the single cell is in contact with the inner surfaces of the second upper tooling and the second lower tooling, and the adhesive film bonding area of ​​the single cell is in contact with the third area of ​​the first upper tooling and the fourth area of ​​the first lower tooling; the third area is located on both sides of the first area, and the fourth area is located on both sides of the second area; The application of a shaping force to the single cell via the shaping device includes: The second upper tooling applies a first leveling force to the reaction zone and distribution zone of the single cell, and the first upper tooling applies a second leveling force to the adhesive film bonding zone of the single cell. Wherein, the shaping force is the sum of the first leveling force and the second leveling force; The first leveling force is calculated based on the surface pressure when multiple single cells are assembled to form a stack, combined with the area of ​​the reaction distribution region of a single cell. The second leveling force is obtained based on the leveling force curve of the adhesive film bonding area; The first temperature is 5-10°C above the softening point of a single cell; The first preset time period is less than or equal to 1 minute; When cooling the single battery and the shaping device, the cooling rate of the single battery and the shaping device is controlled to be less than or equal to 5°C / min.

2. The single-cell shaping method for a fuel cell according to claim 1, characterized in that, include: Throughout the entire thermal shaping process, the ambient humidity of the single battery and the shaping device is controlled within the range of 40%-80%.

3. The single-cell shaping method for a fuel cell according to claim 1, characterized in that, Before preheating the single cell and / or preheating the shaping device, the method further includes: The single cell is placed on a measuring platform, and the first warpage value of the single cell is measured. The measured first warpage value is compared with the qualified value to determine whether the first warpage value is less than or equal to the qualified value. If so, then there is no need to reshape the single cell; If not, the single cell needs to be shaped.

4. The single-cell shaping method for a fuel cell according to claim 3, characterized in that, After the single-cell shaping is completed, the process also includes: The shaped single cell is placed on a measurement platform, and the second warp value of the shaped single cell is measured. Compare the second warping value with the qualified value to determine whether the second warping value is less than or equal to the qualified value; If so, then the plastic surgery will end; If not, the shaped single cell is shaped again until it reaches the qualified value.

5. A single-cell shaping device for a fuel cell, applied to the single-cell shaping method for a fuel cell according to any one of claims 1-4, characterized in that, include: The first upper fixture and the first lower fixture have their inner surfaces corresponding to each other and are both flat surfaces. The second upper fixture and the second lower fixture have their inner surfaces corresponding to each other and are both flat surfaces. Wherein, the first area of ​​the first upper tooling has a first groove, the second upper tooling is embedded in the first groove, and the thickness of the second upper tooling is less than the depth of the first groove; The second region of the first lower tooling has a second groove, and the second lower tooling is embedded in the second groove of the first lower tooling. The thickness of the second lower tooling is less than the depth of the second groove.

6. The single-cell shaping device for a fuel cell according to claim 5, characterized in that, Also includes: At least one limiting block is located between the first upper tooling and the first lower tooling, and the limiting block is used to limit the downward pressing height of the shaping device.

7. The single-cell shaping device for a fuel cell according to claim 5, characterized in that, include: At least two first positioning slots are provided in the third region of the first upper tooling; At least two second positioning slots are provided, and the second positioning slots are provided in the fourth region of the first lower tooling; the second positioning slots correspond one-to-one with the first positioning slots. At least two positioning elements, which position the first upper tooling and the first lower tooling through the first positioning groove and the second positioning groove; The third region is located on both sides of the first region, and the fourth region is located on both sides of the second region.

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