Single cell shaping method and device of fuel cell

Abstract

The invention provides a single cell shaping method and device of a fuel cell, the method is carried out through the shaping device, the shaping device comprises a first upper tool and a first lower tool which are oppositely arranged, the surface of one side, close to the first lower tool, of the first upper tool is a flat surface, and the surface of one side, close to the first upper tool, of the first lower tool is a flat surface; the method comprises the following steps: preheating a single battery in a free state and / or a shaping device, putting the single battery into the shaping device when the single battery is preheated to a first temperature, enabling a first surface of the single battery to be in contact with a first upper tool, and enabling a second surface of the single battery to be in contact with a first lower tool; carrying out heat preservation on the single battery and the shaping device at a first temperature in a first preset time period, and applying shaping force to the single battery until shaping of the single battery is completed; and cooling treatment is performed after the first preset time period ends, and shaping is completed after the second temperature is reached. According to the invention, the shaping force is applied to the single battery for full shaping, and the shaping temperature is controlled to avoid the extrusion and glue overflow problems of the hot melt adhesive film.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a single cell shaping method and device for a fuel cell. Background Art

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

[0003] After hot pressing, single cells experience significant warping due to internal stress. This warping affects the contact state of the stack assembly, causes local stress concentration, and increases battery stack assembly deviation. Warping also affects the distribution of water and gas within the battery, impacting the performance of the stack. Therefore, it is necessary to thermally reshape the single cells to release internal stress, improve the flatness of the cells, and thereby improve the contact state of the stack, reduce stack assembly deviation, and enhance the uniformity of water and gas distribution within the stack.

[0004] In the existing technology, the residual heat after hot pressing of a single cell is usually used to reshape the single cell; vacuum is required during the shaping process to remove part of the heat and improve the contact heat transfer effect; in the patent, a cooling medium is introduced into the lower pressing unit and the supporting unit to reduce the temperature. Through the implementation of the patented method, the single cell enters the natural cooling stage after hot pressing, but the temperature fluctuation range in this stage is large and uncontrollable, which affects the thermal shaping effect of the single cell; or, in the existing technology, a clamping assembly and a temperature regulating structure are used to perform the bonding shaping of the bipolar plate. In the patent, temperature control is performed through the temperature regulating structure, including heating and cooling. The core purpose of heating is to soften the plate so that the plate can be flattened and improve the bonding effect. However, it does not address the problem of bonding deformation of the adhesive film. Summary of the Invention

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

[0006] On the one hand, an embodiment of the present application provides a method for shaping a single cell of a fuel cell. The method is performed using a shaping device, the shaping device including a first upper tooling member and a first lower tooling member, the first upper tooling member being disposed opposite the first lower tooling member, the surface of the first upper tooling member adjacent to the first lower tooling member being a flat surface, and the surface of the first lower tooling member adjacent to the first upper tooling member being a flat surface. The method includes: Preheating the single cell and / or preheating the shaping device, wherein the single cell and the shaping device are in a free state; When preheated to a first temperature, the single cell is placed in a shaping device, wherein a first surface of the single cell contacts the first upper tooling and a second surface of the single cell contacts the first lower tooling; During a first preset time period, the single cell and the shaping device are kept at a first temperature, and a shaping force is applied to the single cell by the shaping device; After the first preset time period ends, the single cell and the shaping device are cooled down, and when the second temperature is reached, the shaping of the single cell is completed; wherein, the shaping device applies a shaping force to the single cell until the shaping of the single cell is completed.

[0007] In one embodiment, the shaping device further comprises: a second upper tooling and a second lower tooling arranged 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 a thickness of the second upper tooling is less than a depth of the first groove; 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 a thickness of the second lower tooling is less than a depth of the second groove; Placing the single cell into the shaping device includes: contacting the reaction distribution area of the single cell with the inner surfaces of the second upper tooling and the second lower tooling, and contacting the adhesive film bonding area of the single cell 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; Applying a shaping force to the single cell by the shaping device includes: applying a first leveling force to the reaction area and distribution area of the single cell by the second upper tooling, and applying a second leveling force to the adhesive film bonding area of the single cell by the first upper tooling; wherein the shaping force is the sum of the first leveling force and the second leveling force.

[0008] In one embodiment, the first leveling force is calculated based on the surface pressure when multiple single cells are assembled to form a battery stack, combined with the area of the single cell reaction distribution zone; the second leveling force is obtained based on the leveling force curve of the film bonding area.

[0009] 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 the single cell and the shaping device are cooled, the cooling rate of the single cell and the shaping device is controlled to be less than or equal to 5°C / min.

[0010] In one embodiment, during the entire thermal shaping process, the humidity of the environment in which the single cell and the shaping device are located is controlled within a range of 40%-80%.

[0011] In one embodiment, before preheating the single cell and / or preheating the shaping device, the process further includes: placing the single cell on a measuring platform to measure a first warpage value of the single cell; 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, there is no need to shape the single cell; if not, the single cell needs to be shaped.

[0012] In one embodiment, after the single cell shaping is completed, the process further includes: placing the shaped single cell on a measuring platform, measuring and obtaining a second warpage value of the shaped single cell; comparing the second warpage value with a qualified value to determine whether the second warpage value is less than or equal to the qualified value; if so, terminating the shaping; if not, shaping the shaped single cell again until the single cell reaches the qualified value.

[0013] On the other hand, in one embodiment, the present application further provides a single cell shaping device for a fuel cell, which is applied to the single cell shaping method for a fuel cell according to any of the above embodiments, comprising: 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; Among them, 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 area 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.

[0014] In one embodiment, the shaping device further comprises: at least one limit block, the limit block being located between the first upper tooling and the first lower tooling, and the limit block being used to limit the pressing height of the shaping device.

[0015] In one embodiment, the shaping device also includes: at least two first positioning grooves, the first positioning grooves are arranged in the third area of the first upper tooling; at least two second positioning grooves, the second positioning grooves are arranged in the fourth area of the first lower tooling; the second positioning grooves correspond one-to-one to the first positioning grooves; at least two positioning members, the positioning members position the first upper tooling and the first lower tooling through the first positioning grooves and the second positioning grooves; wherein 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.

[0016] The beneficial effects of this application compared with the prior art are: The present application preheats a free-state cell and / or shaping device, and when preheated to a first temperature, places the cell into the shaping device; maintains the cell and shaping device at the first temperature for a first preset time period, and applies a shaping force to the cell until shaping is complete; after the first preset time period, cools the cell and shaping device to a second temperature, completing shaping. The present application applies a shaping force to the cell to fully shape it, and controls the shaping temperature to avoid extrusion and overflow of the hot-melt adhesive film. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 This is a schematic diagram of the first structure of a shaping device according to an embodiment of the present application; Figure 2 A schematic diagram of a single cell structure of a fuel cell according to an embodiment of the present application; Figure 3 This is a schematic diagram of a second structure of a shaping device according to an embodiment of the present application; Figure 4 This is a schematic diagram of the steps of shaping method 1 according to an embodiment of the present application; Figure 5 A schematic diagram of temperature and pressure curves during the single cell shaping process is shown for one embodiment of the present application; Figure 6 This is a schematic diagram of the steps of the second shaping method according to an embodiment of the present application; Figure 7 This is an embodiment of the present application. Figure 3 An enlarged schematic diagram of a local A; Figure 8 A schematic diagram of a leveling force curve of a film bonding area according to an embodiment of the present application; Figure 9 This is a schematic diagram showing steps before step S410 according to an embodiment of the present application; Figure 10 This is a schematic diagram of a method for evaluating the warpage of a single cell according to an embodiment of the present application; Figure 11 This is an embodiment of the present application. Figure 9 A schematic diagram of the steps after step S430 is included.

[0019] The above drawings include the following reference numerals: 1-single cell; 2-reaction distribution area; 3-film bonding area; 4-shaping device; 5-first upper tooling; 6-first lower tooling; 7-second upper tooling; 8-second lower tooling; 9-first area; 10-second area; 11-third area; 12-fourth area; 13-first positioning groove; 14-second positioning groove; 15-positioning piece; 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 DESCRIPTION

[0020] The terms "first", "second", "third", etc. are only used to distinguish and describe, and do not indicate the order of arrangement, nor can they be understood as indicating or implying relative importance.

[0021] Furthermore, terms such as "horizontal," "vertical," and "overhanging" do not necessarily imply that a component must be absolutely horizontal or overhanging, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but rather that it can be slightly tilted.

[0022] In the description of this application, it should be noted that the terms "inside", "outside", "left", "right", "up", "down", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are the directions or positional relationships in which the product of the application is usually placed when 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 direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limitations on this application.

[0023] In the description of this application, unless otherwise clearly specified and limited, the terms "set", "install", "connected" and "connect" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be a connection between the internal parts of two elements.

[0024] During the hot pressing process, cells are subjected to high temperature and high pressure to achieve full wetting and bonding of the adhesive film. To ensure efficient bonding, this is often accompanied by rapid cooling. This high temperature, high pressure, and rapid cooling can cause significant warping in the cells. Therefore, to flatten the cells, improve contact with the stack, mitigate assembly deviations, and enhance uniformity of water vapor distribution within the stack, the cells need to be reshaped.

[0025] The present application provides a single cell shaping device for a fuel cell, which is used in a single cell shaping method for a fuel cell. Figure 1 This is a schematic diagram of the first structure of the shaping device shown in an embodiment of the present application, as shown in FIG. Figure 1 As shown, the shaping device includes a first upper fixture 5 and a first lower fixture 6. The inner surface of the first upper fixture 5 corresponds to the inner surface of the first lower fixture 6 and both are flat. During the shaping process, the cell 1 is placed between the first upper fixture 5 and the first lower fixture 6, with the first surface (i.e., top surface) of the cell 1 contacting the first upper fixture 5 and the second surface (i.e., bottom surface) of the cell 1 contacting the first lower fixture 6. The first upper fixture 5 and the first lower fixture 6 apply a shaping force to the cell 1. The shaping device 4 is made of a high-thermal-conductivity material for rapid heat conduction. The high-thermal-conductivity material can be copper, for example.

[0026] In another embodiment, Figure 2 This is a schematic diagram of a single cell structure of a fuel cell according to an embodiment of the present application. Figure 3 This is a schematic diagram of the second structure of the shaping device shown in an embodiment of the present application, as shown in FIG. Figure 2-3 As shown, the single cell 1 includes a reaction distribution area 2 and a film bonding area 3. The shaping device 4 includes a first upper tool 5, a first lower tool 6, a second upper tool 7, and a second lower tool 8. The inner surface of the first upper tool 5 corresponds to the inner surface of the first lower tool 6 and is flat. The inner surface of the second upper tool 7 corresponds to the inner surface of the second lower tool 8 and is flat. The first upper tool 5 includes a first region 9 having a first groove, into which the second upper tool 7 is embedded. The thickness of the second upper tool 7 is less than the depth of the first groove. The first lower tool 6 includes a second region 10 having a second groove, into which the second lower tool 8 is embedded. The thickness of the second lower tool 8 is less than the depth of the second groove. The first upper tool 5 also includes a third region 11, which is located on either side of the first region 9. The first lower tool 6 also includes a fourth region 12, which is located on either side of the second region 10.

[0027] 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 area 11 of the first upper tooling 5 and the fourth area 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 area 11 of the first upper tooling 5 and the fourth area 12 of the first lower tooling 6.

[0028] In one embodiment, the shaping device 4 further includes at least one stopper (not shown) located between the first upper fixture 5 and the first lower fixture 6. The stopper is used to limit the downward pressure of the shaping device 4, preventing the first upper fixture 5 and the second upper fixture 7 from approaching the first lower fixture 6 and the first lower fixture 6 too closely, potentially damaging the battery cells 1. When the first upper fixture 5 and the second upper fixture 7 reach a predetermined distance relative to the first lower fixture 6 and the first lower fixture 6, the stopper prevents the first upper fixture 5 and the second upper fixture 7 from approaching the first lower fixture 6 and the first lower fixture 6 any further. The predetermined distance can be set by the user.

[0029] Furthermore, the limit block can be protruding from the third area 11 of the first upper tooling 5, and a corresponding groove can be set in the fourth area 12 of the first lower tooling 6; or the limit block can be protruding from the fourth area 12 of the first lower tooling 6, and a corresponding groove can be set in the third area 11 of the first upper tooling 5; or grooves can be set correspondingly in the third area 11 of the first upper tooling 5 and the fourth area 12 of the first lower tooling 6. When using the shaping device 4, the limit block is placed in the groove corresponding to the fourth area 12 of the first lower tooling 6, and then the first upper tooling 5 and the first lower tooling 6 are installed through the limit block and the groove in the third area 11.

[0030] In one embodiment, the shaping device 4 also includes: at least two first positioning grooves 13, at least two second positioning grooves 14 and at least two positioning members 15; wherein, the second positioning grooves 14 correspond one-to-one to the first positioning grooves 13; the first positioning grooves 13 are arranged in the third area 11 of the first upper tooling 5; the second positioning grooves 14 are arranged in the fourth area 12 of the first lower tooling 6; the positioning members 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.

[0031] In one embodiment, the present application also provides a single cell shaping method for a fuel cell, which is performed by the shaping device 4 described above. Figure 4 This is a schematic diagram of the steps of the shaping method 1 shown in an embodiment of the present application. Figure 1 When the first structure of the single cell shaping device is used to shape a single cell, Figure 1 and Figure 4 As shown, the method includes: Step S410: preheating the battery cell 1 and / or preheating the shaping device 4, wherein the battery cell 1 and the shaping device 4 are in a free state.

[0032] Among them, preheating is carried out in a free state, and the internal stress of the single cell 1 can be fully released during the preheating process, so that the film can be softened; at the same time, the shaping tooling can also be preheated together, and the single cell 1 and the shaping tooling are preheated to the same temperature state for shaping, which can improve the shaping effect.

[0033] Step S420: When preheated to the first temperature, the single cell 1 is placed in the shaping device 4. Within a first preset time period, the single cell 1 and the shaping device 4 are kept warm at the first temperature, and a shaping force is applied to the single cell 1 by the shaping device 4.

[0034] After reaching the first temperature, the battery is kept warm, and at the same time, the first surface of the single battery 1 is in contact with the first upper tooling 5, and the second surface of the single battery 1 is in 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 so that the adhesive film is uniformly distributed; wherein the shaping force is a fixed value; the first temperature can be set by the user.

[0035] Step S430: After the first preset time period ends, the battery cell 1 and the shaping device 4 are cooled down. When the second temperature is reached, the shaping of the battery cell 1 is completed. The shaping device 4 applies a shaping force to the battery cell 1 until the shaping of the battery cell 1 is completed.

[0036] The single cell 1 and the shaping device 4 are slowly cooled to reach a second temperature, the adhesive film is re-solidified, and the pressure is released after reaching the second temperature. The shaping of the single cell 1 is completed, and the shaped single cell 1 is taken out; the shaping force is a fixed value; the second temperature can be set by the user, or can be the room temperature of the environment in which the single cell 1 and the shaping device 4 are located before preheating; the first preset time period can be set by the user.

[0037] Figure 5 A schematic diagram of the temperature and pressure curves during the single cell shaping process is shown in FIG. Figure 5 As shown, during the preheating phase of the cell 1, taking into account the thermal properties of the hot-melt adhesive film, the cell 1 is preheated to 5-10°C above the softening point of the cell 1. This allows the film to fully soften while preventing excessive fluidity and overflow during the shaping process. During the heat preservation phase of the cell 1, the primary function is to achieve uniform temperature distribution within the cell 1. Since the cell 1 has a thin-walled structure and heat conduction is rapid, the duration of this phase is controlled to be ≤1 minute. During the slow cooling phase of the cell 1, the cooling rate of the cell 1 needs to be controlled to ≤5°C / min to prevent rapid shrinkage of the adhesive film after rapid cooling, eliminate residual stress, and avoid internal stress concentration caused by the rapid cooling process, thereby achieving the shaping of the cell 1. Specifically, the first temperature is 5-10°C above the softening point of the cell 1; the first preset time period is ≤1 minute; and during the cooling process of the cell 1 and the shaping device 4, the cooling rate of the cell 1 and the shaping device 4 is controlled to be ≤5°C / min.

[0038] Specifically, the single cell 1 and / or the shaping device 4 in a free state are preheated at the second temperature. When preheated to the first temperature (5-10°C above the softening point of the single cell 1), the single cell 1 is moved 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 within 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, 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, wherein the second temperature is the room temperature of the environment in which the single cell 1 and the shaping device 4 are located.

[0039] The shaping method provided by the present application includes: preheating the single cell 1 in a free state to fully release the internal stress of the single cell 1; and, after the first preset time period, slowly cooling the single cell 1 to slowly solidify the adhesive film, thereby avoiding rapid cooling and shrinkage of the adhesive film and improving the shaping effect of the single cell 1; when preheating to the first temperature, shaping the single cell 1 while maintaining the temperature and pressure, so that the thickness distribution of the adhesive film is more uniform, thereby improving the bonding quality of the single cell 1. In addition, the temperature is accurately controlled during the shaping process to prevent the single cell 1 from having the problem of hot melt adhesive film extrusion during the shaping process; and the shaping process of the single cell 1 of the present application simulates the assembly state of the single cell 1 in the battery stack, which can improve the shaping effect and improve the contact state of the battery in the battery stack assembly.

[0040] In one embodiment, Figure 6 This is a schematic diagram of the steps of the shaping method 2 shown in an embodiment of the present application. Figure 3 When the second structure of the shaping device shown is used to shape a single cell, Figure 2-6 As shown, step S420 includes: Step S421 : contact the reaction distribution area 2 of the cell 1 with the inner surfaces of the second upper tooling 7 and the second lower tooling 8 , and contact the adhesive film bonding area 3 of the cell 1 with the third area 11 of the first upper tooling 5 and the fourth area 12 of the first lower tooling 6 .

[0041] Further, Figure 7 This is an embodiment of the present application. Figure 3 The enlarged schematic diagram of local A is as follows: Figure 2-7As shown, in order to prevent the single cell 1 from being twisted, stretched, or damaged during the shaping process, and to ensure the flatness and centering of the membrane electrode 16 during the pressurized shaping process, the single cell 1 needs to be shaped with the membrane electrode 16 as a reference. In order to ensure that the membrane electrode 16 is always used as a 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 in contact with the film bonding area 3 is set as the third surface 27, and the second lower tooling 8 is set as the third surface 27. The surface of the upper tooling 7 in contact with the reaction distribution area 2 is set as the fourth surface 28, and 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 in contact with the film bonding area 3 is set as the fifth surface 29, and the surface of the second lower tooling 8 in contact with the reaction distribution area 2 is set as the sixth surface 30, and 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, it is ensured that the membrane electrode 16 is used as the reference line for shaping.

[0042] like Figure 7 As shown, in the bonding area, above the baseline membrane electrode 16 are the anode plate 17, anode film 18, and anode frame 19 of the single cell 1; below the baseline membrane electrode 16 are the cathode frame 20, cathode film 21, and cathode plate 22. In the reaction distribution area 2, above the baseline membrane electrode 16 are the anode plate flow channel 23 and anode GDL 24 (Gas Diffusion Layer), and below the baseline membrane electrode 16 are the cathode GDL 25 (Gas Diffusion Layer) and cathode plate flow channel 26. The first height difference H12 and the second height difference H13 are calculated using the following formulas: H12=H7+H8*(compression rate of anode GDL24)+H9-H1-H2-H3; (1) H13=H11+H10*(cathode GDL25 compression ratio)-H4-H5-H6; (2) Among them, H1 is the anode plate 17 of the single cell 1, H2 is the anode film 18, H3 is the anode frame 19, H4 is the cathode frame 20, H5 is the cathode 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.

[0043] Step S422: Apply a first leveling force to the reaction area and distribution area of the single cell 1 through the second upper tool 7, and apply a second leveling force to the film bonding area 3 of the single cell 1 through the first upper tool 5; wherein the leveling force is the sum of the first leveling force and the second leveling force.

[0044] Specifically, the first leveling force is calculated based on the surface pressure when multiple cells 1 are assembled to form a stack, combined with the area of the reaction distribution area 2 of the cell 1. The specific formula is as follows: F1=P*S; (3) Wherein, F1 is the first leveling force, P is the surface pressure of the battery stack formed by the single cell 1 in the assembled state, and S is the area of the reaction distribution area 2 of the single cell 1.

[0045] Specifically, Figure 8 FIG. 1 is a schematic diagram of a flattening force curve of a film bonding area according to an embodiment of the present application. Figure 7 As shown, the second leveling force is obtained according to the leveling force curve of the adhesive film bonding area.

[0046] Specifically, the second leveling force F2 of the bonding area is calibrated by calibrating the leveling force of the bonding area of the single cell 1. The calibrated leveling displacement and leveling force curve is as follows: Figure 7 As shown, when the leveling displacement is less than S1, the force generated is the leveling force to overcome the warpage of the bonding area of the single cell 1. When the leveling displacement is greater than S1, the force generated is the force to overcome the elastic deformation of the bonding area. This portion is approximately a straight line. F2 is determined by calculating the vertical coordinate of the intersection of the tangent line of the elastic deformation force to overcome the bonding area and the curve of the leveling force to overcome the warpage of the bonding area of the single cell 1 as the bonding area leveling force F2. S1 is the horizontal coordinate of the intersection of the tangent line of the elastic deformation force to overcome the bonding area and the curve of the leveling force to overcome the warpage of the bonding area of the single cell 1.

[0047] In one embodiment, the humidity of the environment surrounding the single cell 1 and the shaping device 4 is controlled within a 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 cell. Furthermore, this dehydration and warping of the membrane electrode 16 increases the risk of leakage and even damage. Therefore, during the thermal shaping process of the single cell 1, it is necessary to control the process humidity within a range of 40-80%, ensuring that the membrane electrode 16 performs thermal shaping in relatively humid conditions to prevent dehydration and warping.

[0048] In one embodiment, Figure 9 This is a schematic diagram showing an embodiment of the present application including steps before executing step S410, as shown in FIG. Figure 9 As shown, before executing step S410, the following steps are also included: Step S910 : placing the cell 1 on a measuring platform, and measuring and obtaining a first warpage value of the cell 1 .

[0049] in, Figure 10 This is a schematic diagram of a method for evaluating the warpage of a single cell 1 according to an embodiment of the present application. Figure 10 As shown, the single cell 1 is placed on a measuring platform, and the height H from the maximum bulge of the single cell 1 to the measuring platform is measured as the first warpage value of the single cell 1 .

[0050] Step S920: Compare 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; wherein the qualified value may be a value defined by the user.

[0051] Step S930: If yes, there is no need to reshape the battery cell 1 .

[0052] Step S940: If not, the battery cell 1 needs to be reshaped.

[0053] In one embodiment, Figure 11 This is an embodiment of the present application. Figure 9 The schematic diagram of the steps after step S430 is included in the embodiment, such as Figure 11 As shown, after the single cell 1 is shaped in step S430, the following steps are further included: Step S1110: placing the shaped single cell 1 on a measuring platform, and measuring and obtaining a second warpage value of the shaped single cell 1.

[0054] Similarly, the shaped cell 1 is placed on a measuring platform, and the height from the maximum bulge of the shaped cell 1 to the measuring platform is measured as the second warpage value of the cell 1 .

[0055] Step S1120: Compare the second warpage value with the qualified value to determine whether the second warpage value is less than or equal to the qualified value; wherein the qualified value may be a value defined by the user.

[0056] Step S1130: If yes, then end the shaping.

[0057] Step S1140: If not, the shaped cell 1 is shaped again until the cell 1 reaches a qualified value.

[0058] In one embodiment, as shown in Table 1 below, the passing value for cell 1 is set at 4 mm. The measured first warpage value (pre-shaping value) is compared with the passing value to determine whether the first warpage value (pre-shaping value) is less than or equal to the passing value of 4 mm. If so, cell 1 does not require shaping; otherwise, it requires shaping. In Table 1, cell number 3 has a first warpage value less than or equal to the passing value of 4 mm, so shaping is not required. Therefore, cell number 3 does not have a warpage improvement ratio, so the post-shaping value and warpage improvement ratio are not entered in the table. Cell numbers 1, 2, and 4 have first warpage values greater than the passing value of 4 mm, requiring shaping. After shaping is completed, the warpage improvement ratios for cells 1, 2, and 4 are calculated. The warpage improvement ratio is the ratio of the difference between the pre-shaping value (first warpage value) and the post-shaping value (second warpage value) to the pre-shaping value (first warpage value). As shown in Table 1, by shaping the single cell 1 using the method and apparatus of the present application, the warping of the single cell 1 can be greatly improved.

[0059] Table 1 Data table of the warpage improvement ratio of single cell before and after shaping

[0060] It should be noted that, unless there is a conflict, the features in the embodiments of this application may 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 may have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of this application shall be included in the scope of protection 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, the shaping device comprising a first upper tool and a first lower tool, the first upper tool being arranged opposite to the first lower tool, the surface of the first upper tool close to the first lower tool being a flat surface, and the surface of the first lower tool close to the first upper tool also being a flat surface; the method comprises: Preheating the single cell and / or preheating the shaping device, wherein the single cell and the shaping device are in a free state; When preheated to a first temperature, the single cell is placed in the shaping device, wherein the first surface of the single cell contacts the first upper tooling and the second surface of the single cell contacts the first lower tooling; During a first preset time period, the single cell and the shaping device are kept at a first temperature, and a shaping force is applied to the single cell by the shaping device; After the first preset time period ends, the single cell and the shaping device are cooled down, and when the temperature reaches the second temperature, the shaping of the single cell is completed; wherein the shaping device applies a shaping force to the single cell until the shaping of the single cell is completed.

2. The method for shaping a single fuel cell according to claim 1, wherein: The shaping device further includes: a second upper tooling and a second lower tooling arranged 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 a thickness of the second upper tooling is less than a depth of the first groove; The second area 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; Placing the single cell into the shaping device comprises: The reaction distribution area of the single cell contacts the inner surfaces of the second upper tooling and the second lower tooling, and the adhesive film bonding area of the single cell contacts 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; Applying a shaping force to the single cell by the shaping device includes: Applying a first leveling force to the reaction area and the distribution area of the single cell through the second upper tooling, and applying a second leveling force to the adhesive film bonding area of the single cell through the first upper tooling; The shaping force is the sum of the first leveling force and the second leveling force.

3. The method for shaping a single fuel cell according to claim 2, wherein: 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 single cell reaction distribution area; The second leveling force is obtained according to a leveling force curve of the adhesive film bonding area.

4. The method for shaping a single fuel cell according to claim 1, wherein: 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 the temperature of the single cell and the shaping device is lowered, the cooling rate of the single cell and the shaping device is controlled to be less than or equal to 5° C. / min.

5. The method for shaping a single fuel cell according to claim 1, wherein: include: During the entire thermal shaping process, the humidity of the environment in which the single cell and the shaping device are located is controlled within the range of 40%-80%.

6. The method for shaping a single fuel cell according to claim 1, wherein: Before preheating the single cell and / or preheating the shaping device, the method further includes: Placing the single cell on a measuring platform and measuring a first warpage value of the single cell; 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, there is no need to reshape the cell; If not, the single cell needs to be reshaped.

7. The method for shaping a single fuel cell according to claim 6, wherein: After the single cell shaping is completed, the method further includes: The shaped single cell is placed on a measuring platform, and a second warpage value of the shaped single cell is measured; 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 cell is shaped again until the cell reaches the qualified value.

8. 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 to 7, characterized in that: include: a first upper tooling piece and a first lower tooling piece, wherein the inner surface of the first upper tooling piece corresponds to the inner surface of the first lower tooling piece and both are flat surfaces; a second upper tooling piece and a second lower tooling piece, wherein the inner surface of the second upper tooling piece corresponds to the inner surface of the second lower tooling piece and both are flat surfaces; 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 area 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.

9. The single cell shaping device for a fuel cell according to claim 8, characterized in that: Also includes: At least one limit block is located between the first upper tooling and the first lower tooling, and the limit block is used to limit the pressing height of the shaping device.

10. The single cell shaping device for a fuel cell according to claim 8, characterized in that: include: at least two first positioning grooves, wherein the first positioning grooves are arranged in the third area of the first upper tooling; at least two second positioning grooves, the second positioning grooves being arranged in the fourth region of the first lower tooling; the second positioning grooves corresponding to the first positioning grooves one-to-one; at least two positioning members, the positioning members positioning the first upper tooling and the first lower tooling through the first positioning groove and the second positioning groove; 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.

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