Buffer and fuel cell stack

Abstract

The present invention provides a buffer and a fuel cell stack, relating to the technical field of fuel cells. The buffer includes a guiding seat, an outer pressing plate, an inner pressing plate, a first buffer member, and a second buffer member. The outer pressing plate and the inner pressing plate are both slidably connected to the guiding seat along the axial direction. The outer pressing plate has a first pressing portion and a second pressing portion. The first end of the first buffer member is fixed relative to the guiding seat, and the second end of the first buffer member abuts against the first pressing portion. The first end of the second buffer member is fixed relative to the guiding seat, and the second end of the second buffer member abuts against the inner pressing plate. A gap is left between the second pressing portion and the inner pressing plate, and the maximum elastic deformation amount of the first buffer member is greater than the gap. The fuel cell stack includes the buffer. It solves the technical problem of poor stability of the stack core in the prior art and achieves the technical effect of stabilizing the stack core size.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and more particularly to a buffer and a fuel cell stack. Background Art

[0002] A fuel cell is an electrochemical energy converter that directly converts the chemical energy in fuel into direct current electricity. A fuel cell stack (referred to as a stack for short) is composed of multiple single cells connected in series. Each single cell includes two electrodes, an anode and a cathode, and an electrolyte element is provided between the two electrodes. By supplying fuel to the anode electrode and air or oxygen to the cathode electrode, an electrochemical reaction is realized, and then a potential difference is generated between the two electrodes, thereby generating electric energy. Because of its advantages such as zero emissions, no noise, long life, and high conversion efficiency, it is widely used in many fields.

[0003] In the prior art, due to the problem of elastic stabilization of the stack core in high-power stacks, the pressing force in the stack core will decay over time, resulting in a reduction in the size of the stack core. This phenomenon is particularly obvious in high-power stacks, and ultimately it will cause the fastening device to become loose, resulting in a decrease in the airtightness and performance of the entire stack, thereby affecting the service life of the battery. At the same time, for extra-high-power stacks applied to large trucks, heavy trucks, and off-road vehicles, a relatively large impact will be generated on the stack core during the driving of the vehicle. Especially in the case of a small car accident, the instantaneous impact can reach dozens of times that of the normal road surface impact. This situation may not cause much damage to the vehicle body, but this relatively large impact will cause irreversible damage to the life stability of the stack core, resulting in the failure of the stabilizer, the loosening of the fastening device, the decrease in the airtightness and performance of the entire stack, and ultimately the damage of the stack, which greatly increases the maintenance cost. Therefore, ensuring the stability of the stack core size is a problem that must be solved for extra-high-power stacks.

[0004] Currently, the methods for eliminating the elastic size of the stack core include bolts, gaskets, and helical springs, etc.; in terms of shock resistance, the method of fixing the helical spring to the vehicle body is mainly adopted.

[0005] However, no matter which of the above methods is adopted, the stability of the stack core is poor. Summary of the Invention

[0006] The purpose of the present invention is to provide a buffer and a fuel cell stack to alleviate the technical problem of poor stability of the stack core existing in the prior art.

[0007] In a first aspect, the present invention provides a buffer, comprising: a guiding seat, an outer pressing plate, an inner pressing plate, a first buffer member, and a second buffer member; the outer pressing plate and the inner pressing plate are both slidably connected to the guiding seat along the axial direction, and the outer pressing plate has a first pressing portion and a second pressing portion; a first end of the first buffer member is fixed relative to the guiding seat, and a second end of the first buffer member abuts against the first pressing portion; a first end of the second buffer member is fixed relative to the guiding seat, and a second end of the second buffer member abuts against the inner pressing plate; the elastic deformation directions of the first buffer member and the second buffer member are consistent with the axial direction; there is a gap between the second pressing portion and the inner pressing plate, and the maximum elastic deformation amount of the first buffer member is greater than the gap.

[0008] Further, an avoidance hole is provided on the inner pressing plate, and the aperture of the avoidance hole is not less than the outer peripheral dimension of the second end of the first buffer member and the outer peripheral dimension of the first pressing portion; the second buffer member is coaxially sleeved outside the first buffer member, the axial dimension of the first buffer member is greater than the axial dimension of the second buffer member, and the first end of the first buffer member is arranged in the avoidance hole in an uncompressed state.

[0009] Further, the guiding seat includes a bottom plate and a positioning column fixedly connected to the bottom plate; the outer pressing plate and the inner pressing plate are both slidably sleeved on the positioning column; the second ends of the first buffer member and the second buffer member both abut against or are fixedly connected to the bottom plate.

[0010] Further, a bushing is provided on the bottom plate, and the bushing protrudes from the bottom plate along the axial direction and extends towards the outer pressing plate; the first buffer member is located inside the bushing, and the outer peripheral dimension of the first buffer member is adapted to the inner wall of the bushing; the second buffer member is slidably sleeved outside the bushing.

[0011] Further, a limiting structure is provided on the positioning column, the limiting structure extends along the radial direction of the positioning column, and the limiting structure abuts against the surface of the inner pressing plate facing the outer pressing plate.

[0012] Further, the limiting structure includes a first locking nut; the first locking nut is sleeved on the positioning column through a thread.

[0013] Further, both the first buffer member and the second buffer member are made of disc springs or helical springs.

[0014] Beneficial effects:

[0015] The buffer provided by the present invention has an outer pressure plate and an inner pressure plate both slidably connected to a guide seat along the axial direction. The elastic deformation directions of the first buffer member and the second buffer member are the same as the axial direction. Since the first end of the first buffer member is fixed relative to the guide seat and the second end of the first buffer member abuts against the first pressing portion, when the outer pressure plate slides along the guide seat under the action of an external pressing force, the first buffer member can be pressed to be compressed and absorb the tolerance dimension, playing a role in stabilizing the core dimension. At the same time, since there is a gap between the second pressing portion and the inner pressure plate and the maximum elastic deformation amount of the first buffer member is greater than the gap, during the process of continuously pressing the outer pressure plate, the second pressing portion can gradually approach the inner pressure plate and abut against the inner pressure plate. At this time, since the second end of the second buffer member abuts against the inner pressure plate, when the second pressing portion continues to press the inner pressure plate, the second buffer member will start to be stressed. At this time, most of the pressure is applied to the second buffer member, and the first buffer member for absorbing the tolerance can be protected by the second buffer member, and the impact energy can be well absorbed. When the buffer is applied to a fuel cell stack, the buffer has a dual function of preventing elastic dimension change of the core and protecting against collision and impact.

[0016] In a second aspect, the present invention provides a fuel cell stack, including: an outer frame, a core, and the buffer according to any one of the foregoing embodiments; the core is located inside the outer frame; the outer frame includes a movable blind end plate, and the buffer is located between the blind end plate and the core; the moving direction of the blind end plate is the same as the axial direction.

[0017] Further, the outer frame further includes an air port end plate, a fastening tie rod, and a second locking nut; the fastening tie rod is used to connect the blind end plate and the air port end plate, and both ends of the fastening tie rod are fixed by the second locking nut; the blind end plate can slide along the fastening tie rod, and the air port end plate is fixed relative to the fastening tie rod.

[0018] Further, a floating plate is provided inside the outer frame; the outer edges on both sides of the floating plate respectively abut against the inner sides of the opposite fastening tie rods; the floating plate is located between the buffer and the core.

[0019] Advantageous effects:

[0020] The fuel cell stack provided by the present invention includes the foregoing buffer. Therefore, the effects and advantages of the fuel cell stack also include the effects and advantages of the buffer, which will not be elaborated herein. Description of the drawings

[0021] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0022] Figure 1 Structural schematic diagram of the buffer provided by the embodiment of the present invention;

[0023] Figure 2 Top view of the buffer provided by the embodiment of the present invention;

[0024] Figure 3 is Figure 2 Cross-sectional view along line A-A;

[0025] Figure 4 Front view of the fuel cell stack provided by the embodiment of the present invention;

[0026] Figure 5 Side view of the fuel cell stack provided by the embodiment of the present invention.

[0027] Icon:

[0028] 100 - Guide seat; 110 - Bottom plate; 120 - Positioning column;

[0029] 200 - Outer pressure plate; 210 - First pressing part; 220 - Second pressing part;

[0030] 300 - Inner pressure plate; 310 - Avoidance hole;

[0031] 400 - First buffer member;

[0032] 500 - Second buffer member;

[0033] 600 - Bush;

[0034] 700 - First locking nut;

[0035] 800 - Outer frame body; 810 - Blind end plate; 820 - Air port end plate; 830 - Tightening pull rod; 840 - Second locking nut; 850 - Floating plate;

[0036] 900 - Stack core. Detailed implementation manners

[0037] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. Components of the embodiments of the present invention usually described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations.

[0038] Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0039] It should be noted that like reference numerals and letters denote like items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0040] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings or the orientation or positional relationship in which the inventive product is customarily placed during use. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive distinction and should not be construed as indicating or implying relative importance.

[0041] In addition, the terms "horizontal", "vertical", "overhanging", etc. do not mean that the components are required to be absolutely horizontal or overhanging, but may be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but may be slightly inclined.

[0042] In the description of the present invention, it should also be noted that unless otherwise clearly specified and defined, the terms "set", "installed", "connected", "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0043] The following will, in conjunction with the accompanying drawings, elaborate in detail some embodiments of the present invention. Without conflict, the features in the following embodiments and the embodiments can be combined with each other.

[0044] In some technologies, bolts, gaskets, disc springs, helical springs, U-shaped fastening devices, etc. are usually adopted to eliminate the elastic dimensions of the core; the method of fixing the helical spring to the vehicle body is adopted for shock resistance.

[0045] The above methods have at least the following problems: In the method of using bolts to eliminate the core size, the load-bearing is on the outer shell, and the core size tolerance is absorbed by relying on the internal end plate and the screwing length of the bolts. Its absorption effect is only once, and it cannot ensure the size stability of the core under long-term use.

[0046] In the method of using gaskets, due to the uncertain size of the tolerance, it is not easy to control the thickness and quantity of the gaskets;

[0047] In the method of using traditional disc springs, it will increase the force on the disc springs, and disc springs of larger sizes are required, which increases the layout cost and space. If the number of disc springs is reduced, the pressure-bearing capacity will be insufficient, resulting in elastic failure.

[0048] To alleviate the above technical problems, this embodiment provides a buffer. When the buffer is used for stabilizing the core size, by setting double disc springs, it can absorb the elastic tolerance of the core in the ±Y direction to alleviate the technical problem of poor stability of the core existing in the prior art. Next, the structure of the buffer will be specifically described with reference to the accompanying drawings.

[0049] Please refer to Figures 1 to 3 , this embodiment provides a buffer, which includes a guide seat 100, an outer pressure plate 200, an inner pressure plate 300, a first buffer member 400, and a second buffer member 500; both the outer pressure plate 200 and the inner pressure plate 300 are slidably connected to the guide seat 100 along the axial direction. The outer pressure plate 200 has a first pressing portion 210 and a second pressing portion 220; the first end of the first buffer member 400 is fixed relative to the guide seat 100, and the second end of the first buffer member 400 abuts against the first pressing portion 210; the first end of the second buffer member 500 is fixed relative to the guide seat 100, and the second end of the second buffer member 500 abuts against the inner pressure plate 300; the elastic deformation directions of the first buffer member 400 and the second buffer member 500 are consistent with the axial direction; there is a gap between the second pressing portion 220 and the inner pressure plate 300, and the maximum elastic deformation amount of the first buffer member 400 is greater than the gap.

[0050] In the buffer provided in this embodiment, the outer pressure plate 200 and the inner pressure plate 300 are both slidably connected to the guide seat 100 along the axial direction. The elastic deformation directions of the first buffer member 400 and the second buffer member 500 are consistent with the axial direction. Since the first end of the first buffer member 400 is fixed relative to the guide seat 100 and the second end of the first buffer member 400 abuts against the first pressing portion 210, when the outer pressure plate 200 slides along the guide seat 100 under the action of an external pressing force, the first buffer member 400 can be pressed to be compressed and absorb the tolerance dimension, playing a role in stabilizing the size of the core 900. At the same time, since there is a gap between the second pressing portion 220 and the inner pressure plate 300, and the maximum elastic deformation amount of the first buffer member 400 is greater than the gap, during the continuous pressing of the outer pressure plate 200, the second pressing portion 220 can gradually approach the inner pressure plate 300 and abut against the inner pressure plate 300. At this time, since the second end of the second buffer member 500 abuts against the inner pressure plate 300, when the second pressing portion 220 continues to press the inner pressure plate 300, the second buffer member 500 will start to be stressed. At this time, most of the pressure is applied to the second buffer member 500, and the first buffer member 400 for absorbing the tolerance can be protected by the second buffer member 500, and the impact energy can be well absorbed. When the buffer is applied to the fuel cell stack, the buffer has the dual functions of preventing the elastic size change of the core and protecting against collision and impact.

[0051] Under the same experimental conditions, it is known from the experimental results that the buffer of this embodiment has an impact resistance performance more than 20 times higher than that of a single set of disc springs.

[0052] This buffer is not limited to the use in small-power fuel cell stacks and can be used in ultra-high-power fuel cell stacks required for large trucks, heavy trucks, off-road vehicles, military vehicles, and extra-large mining trucks.

[0053] Further, referring to Figure 3 , an avoidance hole 310 is provided on the inner pressure plate 300, and the aperture diameters of the avoidance holes 310 are not less than the outer peripheral dimensions of the second end of the first buffer member 400 and the outer peripheral dimensions of the first pressing portion 210. The second buffer member 500 is coaxially sleeved outside the first buffer member 400. The axial dimension of the first buffer member 400 is greater than the axial dimension of the second buffer member 500, and the first end of the first buffer member 400 is arranged in the avoidance hole 310 in the uncompressed state. With such a setting, the space utilization rate can be improved, and the overall layout can be made more reasonable and compact. The setting of the avoidance hole 310 can play a guiding role for the first buffer member 400 and the first pressing portion 210. Coaxially sleeving the second buffer member 500 outside the first buffer member 400 is beneficial to improving the deformation stability of the two.

[0054] Optionally, the avoidance hole 310 may be a circular hole or a rectangular hole. In this embodiment, the aperture of the avoidance hole 310 is larger than the outer peripheral dimension of the second end of the first buffer member 400 and the outer peripheral dimension of the first pressing portion 210. Such a setting is conducive to the installation of other components in the subsequent process.

[0055] Please continue to refer to Figure 3 , the guiding seat 100 includes a bottom plate 110 and a positioning column 120 fixedly connected to the bottom plate 110; both the outer pressing plate 200 and the inner pressing plate 300 are slidably sleeved on the positioning column 120; the second ends of both the first buffer member 400 and the second buffer member 500 are in contact with or fixedly connected to the bottom plate 110.

[0056] In this embodiment, the bottom end of the positioning column 120 is inserted into the bottom plate 110, that is, the two are detachably connected.

[0057] In other embodiments, the bottom end of the positioning column 120 and the bottom plate 110 may also be integrally provided.

[0058] Please refer to again Figure 3 , a bushing 600 is provided on the bottom plate 110. The bushing 600 protrudes axially from the bottom plate 110 and extends towards the outer pressing plate 200; the first buffer member 400 is located inside the bushing 600, and the outer peripheral dimension of the first buffer member 400 is adapted to the inner wall of the bushing 600; the second buffer member 500 is slidably sleeved outside the bushing 600. Such a setting is not only conducive to the installation of the first buffer member 400, and only needs to place the first buffer member 400 into the bushing 600. Among them, the inner hole dimension of the bushing 600 should be larger than the outer dimension of the first buffer member 400 to ensure that there is enough space when the first buffer member 400 expands radially outward during elastic deformation; but also conducive to the installation of the second buffer member 500, that is, the second buffer member 500 can be directly sleeved outside the bushing 600.

[0059] In addition, the setting of the bushing 600 is conducive to maintaining the stability of the first buffer member 400 and the second buffer member 500 during deformation on the premise of facilitating their installation, and further improves the stability of the buffer when bearing impact.

[0060] Furthermore, a limiting structure is provided on the positioning column 120. The limiting structure extends along the radial direction of the positioning column 120, and the limiting structure abuts against the surface of the inner pressing plate 300 facing the outer pressing plate 200. Such a setting plays a role in limiting the reverse movement of the inner pressing plate 300 (that is, during the process of the second buffer member 500 returning to the initial uncompressed state after the external force is eliminated).

[0061] Specifically, refer to Figure 1 or Figure 3, the limiting structure includes a first locking nut 700; the first locking nut 700 is sleeved on the positioning column 120 through a thread.

[0062] Based on the above embodiments, optionally, both the first buffer member 400 and the second buffer member 500 are made of disc springs or helical springs.

[0063] Refer to Figure 4 and Figure 5 , this embodiment also provides a fuel cell stack, which includes an outer frame 800, a stack core 900, and a buffer in front; the stack core 900 is located inside the outer frame 800; the outer frame 800 includes a movable blind end plate 810, and the buffer is located between the blind end plate 810 and the stack core 900; the moving direction of the blind end plate 810 is consistent with the axial direction. The fuel cell stack provided in this embodiment includes the aforementioned buffer. Therefore, the effects and advantages of this fuel cell stack also include the effects and advantages of the buffer, which will not be elaborated here.

[0064] Furthermore, the outer frame 800 further includes an air port end plate 820, a fastening tie rod 830, and a second locking nut 840; the fastening tie rod 830 is used to connect the blind end plate 810 and the air port end plate 820, and both ends of the fastening tie rod 830 are fixed by the second locking nut 840; the blind end plate 810 can slide along the fastening tie rod 830, and the air port end plate 820 is fixed relative to the fastening tie rod 830. With such a setting, on the basis of protecting the stack core 900, the outer frame 800 has a relatively stable structure and can stabilize the size of the stack core 900 in the horizontal direction.

[0065] Even further, a floating plate 850 is provided inside the outer frame 800; the outer edges on both sides of the floating plate 850 are respectively abutted against the inner sides of the opposite fastening tie rods 830; the floating plate 850 is located between the buffer and the stack core 900. With such a setting, it is convenient to fix the bottom plate 110, that is, the bottom plate 110 can be installed on the floating plate 850.

[0066] The buffer is not limited to one, and can be set to multiple according to actual requirements. Multiple buffers are arranged at intervals in the width direction of the stack core 900 on the floating plate 850.

[0067] When there are multiple buffers, multiple buffers can be installed on the floating plate 850 first, and then the floating plate 850 can be placed on the stack core 900.

[0068] Specifically, the floating plate 850 is also provided with a groove, and the bottom plate 110 is embedded in the groove, and this groove can play a certain limiting role on the bottom plate 110.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A buffer, characterized in that, it includes: a guide seat (100), an outer pressure plate (200), an inner pressure plate (300), a first buffer member (400) and a second buffer member (500); both the outer pressure plate (200) and the inner pressure plate (300) are axially slidably connected to the guide seat (100), and the outer pressure plate (200) has a first pressing portion (210) and a second pressing portion (220); a first end of the first buffer member (400) is fixed relative to the guide seat (100), and a second end of the first buffer member (400) abuts against the first pressing portion (210); a first end of the second buffer member (500) is fixed relative to the guide seat (100), and a second end of the second buffer member (500) abuts against the inner pressure plate (300); the elastic deformation directions of the first buffer member (400) and the second buffer member (500) are the same as the axial direction; a gap is left between the second pressing portion (220) and the inner pressure plate (300), and the maximum elastic deformation amount of the first buffer member (400) is greater than the gap; a relief hole (310) is provided on the inner pressure plate (300), and the first end of the first buffer member (400) is inserted into the relief hole (310) in an uncompressed state.

2. The buffer according to claim 1, characterized in that, the aperture diameter of the relief hole (310) is not less than the outer peripheral dimension of the second end of the first buffer member (400) and the outer peripheral dimension of the first pressing portion (210); the second buffer member (500) is coaxially sleeved outside the first buffer member (400), and the axial dimension of the first buffer member (400) is greater than the axial dimension of the second buffer member (500).

3. The buffer according to claim 2, characterized in that, the guide seat (100) includes a bottom plate (110) and a positioning column (120) fixedly connected to the bottom plate (110); both the outer pressure plate (200) and the inner pressure plate (300) are slidably sleeved on the positioning column (120); the second end of the first buffer member (400) and the second end of the second buffer member (500) both abut against or are fixedly connected to the bottom plate (110).

4. The buffer according to claim 3, characterized in that, a bushing (600) is provided on the bottom plate (110), and the bushing (600) protrudes from the bottom plate (110) along the axial direction and extends towards the outer pressure plate (200); the first buffer member (400) is located inside the bushing (600), and the outer peripheral dimension of the first buffer member (400) is adapted to the inner wall of the bushing (600); the second buffer member (500) is slidably sleeved outside the bushing (600).

5. The buffer according to claim 3, characterized in that, A limiting structure is provided on the positioning post (120), the limiting structure extends along the radial direction of the positioning post (120), and the limiting structure abuts against the side of the inner pressure plate (300) facing the outer pressure plate (200).

6. The buffer according to claim 5, wherein, the limiting structure includes a first locking nut (700); the first locking nut (700) is sleeved on the positioning post (120) through a thread.

7. The buffer according to any one of claims 1-6, wherein, both the first buffer member (400) and the second buffer member (500) are made of disc springs or helical springs.

8. A fuel cell stack, wherein, it includes: an outer frame (800), a stack core (900), and the buffer according to any one of claims 1-7; the stack core (900) is located inside the outer frame (800); the outer frame (800) includes a movable blind end plate (810), and the buffer is located between the blind end plate (810) and the stack core (900); the moving direction of the blind end plate (810) is the same as the axial direction.

9. The fuel cell stack according to claim 8, wherein, the outer frame (800) further includes an air port end plate (820), a fastening pull rod (830), and a second locking nut (840); the fastening pull rod (830) is used to connect the blind end plate (810) and the air port end plate (820), and both ends of the fastening pull rod (830) are fixed by the second locking nut (840); the blind end plate (810) can slide along the fastening pull rod (830), and the air port end plate (820) is fixed relative to the fastening pull rod (830).

10. The fuel cell stack according to claim 9, wherein, a floating plate (850) is provided inside the outer frame (800); the outer edges on both sides of the floating plate (850) respectively abut against the inner sides of the opposite fastening pull rods (830); the floating plate (850) is located between the buffer and the stack core (900).

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