A proton exchange membrane fuel cell stack

Abstract

The application discloses a proton exchange membrane fuel cell stack, which comprises a front end plate, a current collecting plate, a tail plate bipolar plate, a proton exchange membrane membrane electrode, a hydrogen fuel cell core, a rear end plate, a butterfly spring assembly, a pressure bearing plate, an upper guard plate, a lower guard plate, a CVP wire harness, a CVP connector and a first CVP insert piece. The front end plate is located at the front end of the stack, and hydrogen, air and cooling liquid inlet and outlet cavities are arranged at the outer end of the front end plate; a first nut matched with a first bolt is embedded at the upper end of the front end plate; and a steel belt groove is arranged at the outer periphery of the front end plate. The front and rear current collecting plates are made of conductive materials, and the main plate-shaped structures are orthogonally arranged with tab terminals and through holes, and are fixed with the front and rear end plates through bolts and nuts. The outer side of the front and tail plate bipolar plates is provided with a recessed part and a cylindrical boss, which are matched with the recessed part and the through hole of the first CVP insert piece to be clamped and fastened. The rear end plate is formed by resin injection molding, and is provided with a recessed part and a cylindrical boss to limit the butterfly spring assembly; and the pressure bearing plate is provided with an annular air-avoiding groove and a cylindrical boss to guide the butterfly spring assembly and the guide pad.

Description

Technical Field

[0001] This specification relates to the field of hydrogen fuel cell technology, and in particular to a proton exchange membrane hydrogen fuel cell stack. Background Technology

[0002] Hydrogen fuel's greatest advantages as an energy source are its pollution-free nature, high efficiency, and recyclability, making it a future direction for new energy development and one of the main energy development directions for fuel cell vehicles. In clean energy power applications, hydrogen fuel cell stacks have become one of the most promising, commercially viable, green, low-carbon, and widely applicable technological development directions. With the advancement of national policies, the commercialization process of hydrogen fuel cell stacks is gradually accelerating. The electrochemical reaction in a hydrogen fuel cell occurs within the stack core. Each hydrogen fuel cell stack consists of multiple fuel cell cells that convert the chemical energy of the fuel into electrical energy. Existing hydrogen fuel cell stacks suffer from significant weight issues, and poor temperature uniformity between different fuel cell cells within the stack affects the overall performance of the hydrogen fuel cell stack.

[0003] Therefore, it is necessary to improve the structure of existing hydrogen fuel cell stacks. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the embodiments of this specification are implemented as follows: The present invention provides a proton exchange membrane fuel cell stack, comprising:

[0005] Front end plate, front current collector plate, rear end plate bipolar plate, proton exchange membrane electrode assembly, hydrogen fuel cell stack core, rear end plate, several butterfly spring assemblies, pressure plate, first CVP insert, second CVP insert and rear current collector plate.

[0006] The front end plate is located at the very front of the hydrogen fuel cell stack. The outer end of the front end plate has a fuel gas hydrogen chamber inlet, a hydrogen chamber outlet after the reaction, an oxidizer gas air chamber inlet, a oxidizer gas air chamber outlet after the reaction, a cooling medium coolant inlet, and a coolant outlet after heat exchange.

[0007] The front end plate is obtained by injection molding using resin material as the base material; the upper end of the front end plate is provided with a first nut for fastening with the first bolt by pre-embedding, and the first nut is integrally formed with the front end plate during the injection molding process by pre-embedding.

[0008] The front current collector is made of conductive material. The main body of the front current collector is a first plate-shaped structure. A first electrode is integrally provided at the middle position of the upper end of the first plate-shaped structure. The first electrode is orthogonally arranged with the first plate-shaped structure. Several first through holes are opened on the first electrode. After the first bolt is screwed into the first through holes and tightened with the pre-embedded first nut, the front current collector is fixed to the front end plate. This makes the plate-shaped structure of the front current collector fit tightly against the inner end of the front end plate.

[0009] The hydrogen fuel cell stack is located at the rear end of the front current collector. The hydrogen fuel cell stack is composed of multiple stacked single cells. A front tail plate bipolar plate is located at the front end of the hydrogen fuel cell stack, and a rear tail plate bipolar plate is located at the rear end of the hydrogen fuel cell stack. A first recess is provided near the outer side of the front tail plate bipolar plate. A cylindrical boss is provided in the middle of the first recess. A second through hole is provided at the mounting position of the first CVP insert. The size of the second through hole matches the size of the cylindrical boss. The shape of the first recess matches the shape of the mounting position, so that after the cylindrical boss is inserted into the second through hole, the mounting position and the first recess are locked together. The second CVP insert is fixedly provided on the rear tail plate bipolar plate.

[0010] The hydrogen fuel cell stack is composed of multiple sets of bipolar plates and the proton exchange membrane electrode assembly.

[0011] The rear current collector is disposed behind the bipolar plate of the rear tail plate, and the rear end plate is disposed behind the rear current collector. The rear end plate is injection molded using a resin material matrix. A second nut for fastening with a second bolt is pre-embedded at the upper end of the rear end plate. The second nut is integrally formed with the rear end plate during injection molding. The rear current collector is made of conductive material, and its main body is a second plate-shaped structure. A second electrode lug is integrally disposed at the middle position of the upper end of the second plate-shaped structure, and the second electrode lug is orthogonally arranged to the second plate-shaped structure. Several second through holes are formed on the second electrode lug. After the second bolt is screwed into the second through holes and tightened with the pre-embedded second nut, the rear current collector and the rear end plate are fixed, ensuring that the plate-shaped main body of the rear current collector is flush against the inner end of the rear end plate.

[0012] During the injection molding process, the rear end plate has several second recesses integrally injection molded on its outer end. Each of the several second recesses has a second columnar boss injection molded inside. The second columnar boss is used to limit the movement of the butterfly spring assembly. The butterfly spring assembly includes a guide pad and several disc springs. The guide pad includes an integrally formed base and an annular guide shaft. The guide pad has a contraction opening on one side of the axial direction. The inner diameter of the disc spring matches the outer diameter of the annular guide shaft.

[0013] The pressure plate is provided behind the rear end plate. The side of the pressure plate that is in contact with the rear end plate has a plurality of annular clearance grooves. The opening position of each of the plurality of annular clearance grooves corresponds to the opening position of the second recess at the corresponding position. A third columnar boss is provided in each of the plurality of annular clearance grooves. The third columnar boss is used to extend into the opening at the upper end of the annular guide shaft at the corresponding position.

[0014] Preferably, a plurality of reinforcing ribs are provided on the other side of the pressure plate. The reinforcing ribs are used to locally reinforce the stress area of ​​the pressure plate to improve the local stiffness and local strength of the pressure plate.

[0015] Preferably, the outer periphery of the front end plate and the rear end plate are provided with equally spaced steel strip grooves;

[0016] The battery stack also includes several steel strips. Each steel strip passes through a corresponding steel strip groove and is wound around the outermost periphery of the hydrogen fuel cell stack to maintain the bearing force of the hydrogen fuel cell stack. The steel strips are made of stainless steel.

[0017] Preferably, the front end plate structure has a solid surface in the middle for overall structural reinforcement; wherein the draft depth on the left and right sides of the solid surface is equal to reduce the deformation of the front end plate caused by uneven thermal expansion and contraction after demolding; wherein a rectangular grid structure is provided on the left and right sides of the solid surface.

[0018] Preferably, the battery stack further includes an upper protective plate and a lower protective plate, both of which have a structure with uniformly distributed micropores; the upper protective plate is disposed above the hydrogen fuel cell stack core, and the lower protective plate is disposed below the hydrogen fuel cell stack core; the upper and lower protective plates are used to improve electrical insulation strength and protect the hydrogen fuel cell stack core; both the upper and lower protective plates are made of insulating material.

[0019] Preferably, the battery stack further includes a CVP harness and a CVP connector; wherein the CVP harness is connected to the CVP connector for transmitting electrical signals and data acquisition; and the CVP connector is used to enable electrical signal conduction between the first CVP insert and the CVP harness.

[0020] Preferably, the front end plate and the rear end plate are provided with several grid structures at their outer ends during the injection molding process to reduce weight.

[0021] One embodiment of this specification can achieve the following beneficial effects:

[0022] 1. The front and rear current collectors are made of conductive materials and are tightly fixed to the front and rear end plates with bolts and nuts to ensure efficient current conduction and collection. The bipolar plates of the front and rear end plates and the first CVP insert are snapped together to prevent problems such as poor contact and increased resistance caused by loosening or displacement of components, thereby improving the overall conductivity and stability of the stack and ensuring power generation efficiency.

[0023] 2. Resin injection molding of the front and rear end plates shortens the manufacturing cycle, improves dimensional accuracy and consistency, reduces energy consumption and cost compared to traditional machined end plates, and offers design flexibility, such as the layout of solid surfaces and grid structures on the front end plate. This enhances structural strength while optimizing the molding process through draft design, reducing defects, and improving production efficiency and product quality.

[0024] 3. The end plate pre-embedded nut process integrates the nut and the end plate, enhancing connection reliability. During assembly, the bolt is directly screwed into the pre-embedded nut, eliminating the need for additional nut installation procedures, improving efficiency and making the connection more secure. This maintains the stability of the fuel cell stack structure under complex operating conditions, reduces the risk of failure caused by loose connections, and ensures long-term stable operation of the fuel cell stack.

[0025] 4. The end plates are precisely positioned with hydrogen, air, and coolant inlets and outlets, creating a smooth channel for the introduction of reaction gases and heat exchange. Hydrogen and air arrive at the electrode area in an orderly manner through the inlets, where they react efficiently at the proton exchange membrane electrode. The coolant circulates through the inlets, carrying away heat in a timely manner, ensuring that all components of the fuel cell stack operate within a suitable temperature range, maintaining the stability of the proton exchange membrane performance and the high efficiency and continuity of the electrochemical reaction, and solving the problem of performance loss due to uneven temperature.

[0026] 5. The end plate wraps around the edge of the current collector, which greatly reduces the rate of heat loss. Since the injection-molded end plate material has extremely low thermal conductivity, this maximizes the temperature of the first and last cells and the core, improving the performance consistency of each cell in the stack.

[0027] 6. One side of the pressure plate is tightly fitted to the rear end plate, and the other side is provided with several reinforcing ribs. The layout of the reinforcing ribs can be determined by precise mechanical analysis and distributed in a well-organized manner according to the density of the pressure plate. The ribs are denser in areas bearing greater pressure and stress concentration, such as near the center of the fuel cell stack or fixed points, so that the overall force is reasonably distributed to various local areas, avoiding stress concentration that could cause deformation or damage, improving local stiffness and strength, and steadily maintaining the structural shape of the fuel cell stack.

[0028] Of course, implementing any product or method of the present invention does not necessarily require achieving all of the advantages described above at the same time. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments or prior art of this specification, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is an exploded view of the structure of a proton exchange membrane fuel cell stack provided in the embodiments of this specification;

[0031] Figure 2 This is a schematic diagram of the overall structure of the proton exchange membrane fuel cell stack and its working chamber provided in the embodiments of this specification.

[0032] Figure 3 This is a schematic diagram of the front-end plate assembly in the proton exchange membrane fuel cell stack provided in the embodiments of this specification.

[0033] Figure 4 This is a schematic diagram of the first CVP insert and its mounting position in the proton exchange membrane fuel cell stack provided in the embodiments of this specification;

[0034] Figure 5 This is an assembly diagram of the front-end plate assembly in the proton exchange membrane fuel cell stack provided in the embodiments of this specification;

[0035] Figure 6 This is an assembly diagram of the back-end plate assembly of the proton exchange membrane fuel cell stack provided in the embodiments of this specification;

[0036] Figure 7 An exploded view of the back-end plate assembly and steel strip in the proton exchange membrane fuel cell stack provided in the embodiments of this specification;

[0037] Figure 8 This is a structural diagram of the injection-molded end plate of the proton exchange membrane fuel cell stack provided in the embodiments of this specification;

[0038] Figure 9 This is a schematic diagram of the structure of the butterfly spring assembly in the proton exchange membrane fuel cell stack provided in the embodiments of this specification;

[0039] Figure 10 This is a schematic diagram of the condensate droplets that may be generated when using the proton exchange membrane fuel cell stack provided in the embodiments of this specification.

[0040] Wherein, 1 represents the front end plate, where 101 represents the fuel gas hydrogen chamber inlet, 102 represents the combustion-supporting gas air chamber inlet, 103 represents the cooling medium coolant inlet, 104 represents the hydrogen chamber outlet remaining after the reaction, 105 represents the combustion-supporting gas air chamber outlet remaining after the reaction, 106 represents the coolant outlet after heat exchange, 107 represents the steel strip groove, and 108 represents the first nut; 2 represents the front manifold, where 201 represents the first plate-shaped structure, 202 represents the first electrode lug, and 2021 represents the first through hole; 3 represents the front and rear bipolar plates, where 301 represents the first recess, and 302 represents the first cylindrical boss; 4 represents the steel strip, 5 represents the proton exchange membrane electrode, and 6 represents the... The diagram shows the hydrogen fuel cell stack core. 7 represents the rear end plate, 8 represents the disc spring assembly, where 81 represents the guide pad, 82 represents the disc spring, 811 represents the base, and 812 represents the annular guide shaft; 9 represents the pressure plate, 10 represents the upper guard plate, 11 represents the lower guard plate, 12 represents the CVP wiring harness, and 13 represents the CVP connector; 14 represents the first CVP insert, where 1401 represents the mounting part and 1402 represents the second through hole; 15 represents the rear manifold, 16 represents the second cylindrical boss, 17 represents the annular clearance groove, 18 represents the third cylindrical boss, 19 represents the second recess, 20 represents the contraction opening, 21 represents the reinforcing rib, 22 represents the solid surface, 23 represents the condensate droplet, and 24 represents the line contact. Detailed Implementation

[0041] The following description is provided to enable those skilled in the art to implement the invention. Other obvious substitutions, modifications, and variations will arise for those skilled in the art. Therefore, the scope of protection of this invention should not be limited to the exemplary embodiments described herein.

[0042] Those skilled in the art will understand that, unless specifically indicated herein, the term “a” should be understood as “at least one” or “one or more”, meaning that in one embodiment the number of an element may be one, while in another embodiment the number of the element may be multiple.

[0043] Those skilled in the art should understand that, unless specifically indicated herein, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., refer to the orientation or position based on the accompanying drawings, and are merely for the convenience of describing the invention, and do not indicate or imply that the devices or elements involved must have a specific orientation or position. Therefore, the above terms should not be construed as limiting the invention.

[0044] The technical solutions 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 only some embodiments of the present invention, and not all embodiments.

[0045] Figure 1 This is an exploded view of the structure of a proton exchange membrane fuel cell stack provided in the embodiments of this specification; Figure 2 This is a schematic diagram of the overall structure of the battery stack and its working chamber. Figure 3 This is a schematic diagram of the front-end board assembly in a battery stack. Figure 4 This is a schematic diagram of the first CVP insert and its mounting position in the battery stack; Figure 5 This is an assembly diagram of the front-end board assembly in a battery stack. Figure 6 This is an assembly diagram of the back-end plate assembly of the proton exchange membrane fuel cell stack provided in the embodiments of this specification; Figure 7 This is an exploded view of the rear end plate assembly and steel strip in the battery stack. Figure 8 This is a structural diagram of the injection molding of the middle end plate of the fuel cell stack. Figure 9 This is a schematic diagram of the butterfly spring assembly in a battery stack. Figure 10 This is a schematic diagram illustrating the possible condensation droplets that may occur when using the proton exchange membrane fuel cell stack provided in the embodiments of this specification. The following refers to the accompanying drawings. Figures 1 to 10 The technical solutions of the embodiments of the present invention will be described in detail.

[0046] As shown in the figure, the proton exchange membrane fuel cell stack provided in the embodiments of this specification includes a front end plate 1, a front current collector plate 2, a rear end plate bipolar plate 3, a proton exchange membrane electrode 5, a hydrogen fuel cell stack core 6, a rear end plate 7, several butterfly spring assemblies 8, a pressure plate 9, a first CVP insert 14, a second CVP insert, and a rear current collector plate 15.

[0047] The front-end plate 1, located at the very front of the hydrogen fuel cell stack, primarily serves as a supporting structure, ensuring the stack's stability and safety. Specifically, the front-end plate 1 includes inlets and outlets for reactant gases and cooling media, making it a crucial component of the entire stack structure. Figure 2 As shown, Figure 2The diagram shows the working chamber of the battery stack, which has a hydrogen gas chamber inlet 101, a hydrogen gas outlet 104 after the reaction, an air gas chamber inlet 102, an air gas outlet 105 after the reaction, a coolant liquid inlet 103, and a coolant liquid outlet 106 after heat exchange at the outer end of the front end plate 1.

[0048] In this structure, reactant gases (hydrogen and oxygen) are precisely introduced into the electrode region inside the fuel cell stack through specific openings, supplying raw materials for the electrochemical reactions in the core area of ​​the proton exchange membrane fuel cell. Hydrogen enters the anode side through a dedicated opening, while oxygen reaches the cathode side through a corresponding opening. The two react at the proton exchange membrane electrode, driving the directional movement of electrons to form an electric current. Simultaneously, a cooling medium (such as water or coolant) circulates through specific inlet and outlet openings. When the fuel cell stack generates heat during operation, the cooling medium efficiently absorbs heat and removes it from the stack system through heat exchange, maintaining suitable operating temperatures for all components. This ensures the stable performance of key components such as the proton exchange membrane and electrodes, and the continuous and efficient electrochemical reactions. It is an indispensable key structural element for stable and reliable power generation, improving the overall performance of the fuel cell stack and extending its service life.

[0049] Existing hydrogen fuel cell stack end plates are formed by machining, meaning they are manufactured using traditional mechanical processing methods (such as turning, milling, drilling, etc.). This method typically requires a long processing cycle, has low dimensional accuracy consistency, and relatively high production energy consumption and cost. To address this issue, the front end plate 1 in this application is injection molded using resin material as the base material. A first nut 108 for fastening with a first bolt is pre-embedded at the upper end of the front end plate 1. The first nut 108 is integrally formed with the front end plate 1 during the injection molding process using a pre-embedding process.

[0050] A front current collector 2 is installed behind the front-end board 1 to efficiently collect the current generated by the single cell on the anode side, such as... Figure 3 As shown, Figure 3 This is a structural diagram of the front-end board assembly. Figure 3In the first plate, the main body of the front current collector 2 is a first plate structure 201. This structure can be customized according to the internal layout and mechanical principles of the fuel cell stack. While ensuring stability, it provides reasonable space for the flow of gas and coolant, effectively avoiding channel blockage and flow interference, ensuring smooth transmission of the reaction medium, and maintaining the stability of the electrochemical reaction. A first tab 202 is integrally provided at the middle position of the upper end of the first plate structure 201. The integrally formed first tab 202 is orthogonally arranged with the first plate structure 201. This arrangement can significantly shorten the current transmission path and reduce resistance, creating favorable conditions for efficient current collection and discharge, ensuring that electrical energy is rapidly conducted to the external circuit and enhancing the power output capability of the fuel cell stack. Several first through holes 2021 are provided on the first tab 202. The diameter of the first through holes 2021 is precisely matched with the first bolt, with tolerances controlled within the allowable range to ensure a tight fit. After the first bolt is screwed into the first through hole 2021 and tightened with the pre-embedded first nut 108, the fuel cell stack can be fully opened. The front current collector 2 is fixed to the front end plate 1, and the plate structure of the front current collector 2 is tightly attached to the inner end of the front end plate 1 to ensure good electrical contact and mechanical stability. This prevents faults such as poor contact and sudden resistance changes caused by loosening during operation, and effectively ensures the reliable operation and stable performance of the fuel cell stack. At the same time, this is equivalent to providing an end plate structure style for embedded installation of the current collector. This design allows the end plate to wrap around the edge of the current collector, thereby greatly reducing the rate of temperature loss. Since the injection-molded end plate material has extremely low thermal conductivity, this maximizes the temperature of the first and last cells and the core of the stack to be kept close, improving the performance consistency of each cell in the fuel cell stack. Considering that temperature is one of the most sensitive factors for hydrogen fuel cell stacks during operation, when the current collector is exposed to the air, excessive heat loss from the beginning and end of the stack core can lead to a decline in the performance of the individual cells at the beginning and end. In this case, since the current collector is typically made of highly conductive materials (such as copper, aluminum, and their alloys), which are also good thermal conductors, a significant amount of heat is lost to the air during fuel cell operation. This results in a temperature difference between the beginning and end of the stack and the core, which may affect the efficiency and performance consistency of the hydrogen fuel cell stack. The embedded current collector installation method in this application allows the end plates to wrap around the edges of the current collector, significantly reducing the rate of heat loss. Because the injection-molded end plate material has extremely low thermal conductivity, it maximizes the temperature of the beginning and end cells to be close to that of the core, improving the performance consistency of each cell in the stack.

[0051] The front current collector 2 is typically made of metallic materials with multiple properties such as high conductivity, low contact resistance, and corrosion resistance, such as copper, aluminum, and titanium. These materials have low resistance and high conductivity, which ensures smooth current conduction in the current collector and reduces power loss. During stack operation, the current collector can effectively collect the current generated by each cell in the hydrogen fuel cell stack, aggregate and integrate it, and transmit it to the external circuit to provide a stable power supply to the load. The current collector also has good thermal conductivity while collecting and transmitting current.

[0052] A hydrogen fuel cell stack core 6 is set at the rear end of the front current collector 2. The hydrogen fuel cell stack core, as the core component of the stack, is composed of multiple single cells stacked in an orderly manner. A front tail plate bipolar plate 3 is set at the front end of the hydrogen fuel cell stack core 6, and a rear tail plate bipolar plate is set at the rear end of the hydrogen fuel cell stack core 6. Figure 4 This is a schematic diagram of the first CVP insert and its mounting position in the battery stack, as shown below. Figure 4 As shown in the right-hand sub-figure, a first recess 301 is provided on the front and rear bipolar plate 3 near the outer side, and a first columnar boss 302 is provided in the middle of the first recess 301. Figure 3As shown in the left sub-figure, a second through hole 1402 is provided at the mounting portion 1401 of the first CVP insert 14. The size of the second through hole 1402 matches the size of the first cylindrical boss 302, and the shape of the first recess 301 matches the shape of the mounting portion 1401. During assembly, the first cylindrical boss 302 smoothly inserts into the second through hole 1402, so that the mounting portion 1401 and the first recess 301 are tightly engaged and secured together, forming a stable and reliable connection structure. The installation of the metal sheet used for voltage acquisition of single cells in existing hydrogen fuel cell stacks is relatively troublesome, mainly because conductive adhesive is required for bonding and fixing before bonding the bipolar plates and single cells. This process is not only time-consuming and reduces the overall production efficiency of the product, but also makes it difficult to precisely control the amount of conductive adhesive: if too much adhesive is used, it may cause local cracking when the bipolar plates and single cells are bonded after curing; if too little adhesive is used, it will lead to unreliable bonding and easy detachment. In this application's technical solution, the first recessed portion 301 is used for the installation of the first CVP insert 14, and is assembled with the mounting portion 1401 with tolerance matching, thereby simplifying the installation process. It eliminates the need for conductive adhesive, making assembly simple, quick, and saving on auxiliary materials during the hydrogen fuel cell stack production process. This not only improves production efficiency but also reduces problems that may arise from improper use of conductive adhesive, such as localized cracking due to excessive hardening or weak bonding due to insufficient adhesive. Similarly, one end of the bipolar plate on the rear tail plate is connected to the second CVP insert via a similar boss structure design. The hydrogen fuel cell stack core 6 is composed of multiple sets of bipolar plates and proton exchange membrane electrode 5 stacked together. Each single cell in the stack core also has a CVP insert. The proton exchange membrane electrode is the site of the electrochemical reaction between hydrogen and oxygen, generating electrical energy. It isolates the anode and cathode from air and hydrogen and conducts protons. Specifically, in this process, hydrogen gas is introduced to the anode side, where hydrogen molecules decompose into protons and electrons. Protons pass through the proton exchange membrane to the cathode, while electrons flow through an external circuit to form an electric current. At the cathode side, oxygen combines with protons and electrons to form water, releasing heat energy. Throughout the process, the proton exchange membrane not only conducts protons but also isolates gases, ensuring the safe conduct of the reaction.

[0053] Continuing with the description of the battery stack structure provided in the embodiments of this specification, a rear current collector 15 is provided after the bipolar plate of the rear tail plate for collecting the current of the single cell on the cathode side and conducting it to the external load. A rear end plate 7 is provided after the rear current collector 15. The rear end plate 7 is injection molded using a resin material as the matrix. A second nut for fastening with a second bolt is provided at the upper end of the rear end plate by a pre-embedding method. The second nut is integrally formed with the rear end plate 7 during the injection molding process using a pre-embedding process. The rear current collector 15 is made of conductive material, and the main body of the rear current collector 15 is a second plate-shaped structure. The upper end of the second plate-shaped structure... A second electrode lug is integrally provided in the middle position, and the second electrode lug is orthogonally arranged with the second plate structure. Several second through holes are opened on the second electrode lug. After the second bolt is screwed into the second through hole and tightened with the pre-embedded second nut, the rear collector plate 15 and the rear end plate 7 are fixed, so that the plate body of the rear collector plate 15 is close to the inner end of the rear end plate 7. The material of the rear collector plate 15 is the same as that of the front collector plate 2, and will not be described again here. At the same time, in this structure, the rear end plate 7 also wraps around the edge of the rear collector plate 15, thereby greatly reducing the rate of temperature loss. The relevant technical effects have been described in detail above, and will not be described again here.

[0054] During injection molding, the rear end plate 7 has several second recesses 19 integrally injection molded on its outer end. Each of these second recesses has a second columnar boss 16 injection molded within it. The second columnar boss 16 is used to limit the movement of the disc spring assembly 8. The disc spring assembly 8 includes a guide pad 81 and several disc springs 82. The guide pad 81 includes an integrally formed base 811 and an annular guide shaft 812. The guide pad 81 has a contraction opening 20 on one axial side. The inner diameter of the disc springs 82 matches the outer diameter of the annular guide shaft 812. The base 811 provides a stable support platform for the disc springs 82, ensuring accurate vertical positioning of the springs, maintaining operational stability, and preventing performance fluctuations and structural damage caused by lateral displacement. The annular guide shaft 812 precisely matches the inner diameter of the disc springs 82, providing a tight fit and radial positioning of the springs, constraining radial displacement, ensuring that compression rebound follows a predetermined axial path, and guaranteeing stable and reliable mechanical performance of the assembly. The shape and size of the contraction port 20 are determined according to the mechanical characteristics and working stroke of the disc spring 82, reserving sufficient space for dynamic changes in the spring shaft diameter, buffering and absorbing the complex stress generated by the operation of the fuel cell stack, effectively preventing stress concentration damage to components, and improving the service life and reliability of the assembly. The disc spring 82 is the core elastic element, which can be made of high-quality steel and precision machined. Multiple disc springs 82 are precisely stacked according to design requirements to form an elastic energy storage and release unit. The springs work closely together to ensure uniform force distribution and avoid local stress concentration failure. The guide pad 81 can be made of high-strength, high-toughness, wear-resistant engineering plastics or metal alloys with good self-lubricating properties, such as polyetheretherketone plastic, copper-based or nickel-based alloys, to provide solid support for the stable and reliable operation of the disc spring assembly.

[0055] Continuing with the description of the battery stack structure, a pressure plate 9 is set behind the rear end plate 7. Several annular clearance grooves 17 are opened on the side of the pressure plate 9 that is in contact with the rear end plate 7. The opening position of each annular clearance groove corresponds to the opening position of the second recess at the corresponding position. A third columnar boss 18 is provided in each annular clearance groove. The third columnar boss 18 is used to extend into the opening at the upper end of the annular guide shaft 812 at the corresponding position, so that the upper end of the annular guide shaft 812 extends into the groove of the annular clearance groove.

[0056] As mentioned earlier, in this application's technical solution, the front end plate 1 and the rear end plate 7 are obtained by injection molding using resin material as the base material. Specifically, thermoplastic or thermosetting resin is heated to a molten state, then injected under high pressure into a pre-designed mold, and after cooling and solidification, it forms a component of the required shape and size. During the injection molding process, the front end plate 1 and the rear end plate 7 may have several grid structures at their outer ends (the grid structures are composed of...). Figure 3As can be seen, to reduce weight, the grid structure can have a uniform wall thickness. This refers to the grid-like structure used in the endplate design of the hydrogen fuel cell stack, where the wall thickness is uniform. This design facilitates draft molding via injection molding, improving production efficiency and product quality. The internal structure of the endplate (such as front plate 1 or rear plate 7) can use grids of different shapes, not limited to rectangles, but also rings or rhombuses. The grid structure helps achieve lightweight design, avoiding the problems of large volume and weight caused by overall thickening, as well as uneven material shrinkage and large dimensional deviations. During injection molding, a double-sided draft molding process can be used to remove the front plate 1 and rear plate 7 from the mold. Double-sided draft molding refers to a small-angle inclination on the inner or outer wall of the mold for easy demolding. This design makes it easier to remove the molded part from the mold, avoiding jamming problems caused by vertical surfaces. In the end plate structure of the technical solution of this application, the draft angle can be 3°, or it can be 1°, 2°, etc., in order to reduce defects generated during injection molding and improve production efficiency.

[0057] The first nut 108 fitted to the upper end of the front-end plate 1 functions to tightly engage with the first bolt for a fastening effect. This nut is pre-embedded and integrated with the front-end plate 1 during injection molding. Specifically, at the start of the injection molding process of the front-end plate 1, the first nut 108 is precisely positioned in a specific location in the mold. As the thermoplastic or thermosetting resin melts under heat, it is injected into the mold cavity under high pressure. After cooling and solidification, the resin material evenly coats the nut, making it firmly embedded in the internal structure of the front-end plate 1, ultimately achieving an integral molding state between the nut and the front-end plate 1. In this way, during the subsequent assembly of the hydrogen fuel cell stack, it is only necessary to screw the first bolt directly into the pre-embedded first nut 108 to efficiently achieve a stable connection between the front-end plate 1 and related components. This not only significantly reduces the complicated process of installing additional nuts and improves the overall assembly efficiency, but also greatly enhances the bonding strength between the nut and the front-end plate 1 due to the integrated structural characteristics, effectively ensuring the stability and safety of the overall architecture of the hydrogen fuel cell stack under complex operating conditions.

[0058] Figure 9 This is a schematic diagram of the disc spring assembly in a proton exchange membrane fuel cell stack provided in the embodiments of this specification. In this embodiment, the disc spring assembly in the hydrogen fuel cell stack and its structure is equivalent to providing a guide pad structure with a shrinkage opening that has shaft diameter shrinkage and spacing guiding positioning functions. To maintain the holding force of the hydrogen fuel cell stack core, a disc spring assembly with buffering and compensating core assembly forces is required. The disc spring is a conical structure, and multiple disc springs make line contact through the apex of the cone during assembly (e.g., ...). Figure 9 As shown, Figure 9 The location indicated by reference numeral 24 (indicating contact line) has a small contact area. When a single disc spring shifts, it can easily increase the force on other disc spring assemblies, leading to uneven bearing force on the hydrogen fuel cell stack core. The guide pad's shaft diameter for mounting the disc spring is close to the inner diameter of the disc spring, eliminating the need for alignment and secondary correction during installation. When the disc spring is compressed and buffers, compensating for the stack bearing force, the shaft diameter can contract and rebound along with the inner diameter of the disc spring, always maintaining its directional state and preventing shifting or jamming.

[0059] The working principle of the disc spring assembly 8 mentioned above is explained below. During fuel cell stack assembly, the disc spring assembly 8 is placed at a specific position between the rear end plate 7 and the pressure plate 9. The second recess and the first columnar boss in the injection-molded part of the rear end plate 7, the annular clearance groove of the pressure plate 9 and the third columnar boss 18 in the groove work together to precisely limit and firmly lock the position of the disc spring assembly 8 in cooperation with the guide pad 81, preventing displacement from affecting the fuel cell stack performance. During fuel cell stack operation, changes in operating conditions generate complex stress and load fluctuations. When external pressure is applied to the pressure plate 9, the pressure is evenly transmitted to the disc spring assembly 8 through the pressure plate 9. The disc spring 82 is compressed under force, and the elastic potential energy increases with the increase of deformation, efficiently storing energy. During this process, the annular guide shaft 812, with its contraction opening design, can precisely constrain the radial displacement of the spring, ensuring stable compression and avoiding tilting and jamming. When the stack operating conditions change and the bearing force needs to be adjusted, the disc spring 82 releases energy and rebounds according to its own elastic properties, driving the pressure plate 9 to apply a reverse force to the stack to compensate for the change in bearing force and maintain stable operation of the structure. By precisely designing the specifications, quantity, and dimensions of the disc spring 82 and the guide pad 81, the disc spring assembly 8 can flexibly and accurately respond to the different operating conditions of the stack, ensuring a stable and appropriate bearing force for the core, improving the stack's reliability, durability, and overall performance, and providing a solid guarantee for the stable and efficient operation of the fuel cell system.

[0060] The center of the guide pad features an annular guide shaft that fits tightly into the inner hole of the disc spring. Its diameter is precisely designed according to the spring specifications, with strict tolerance control to ensure smooth, jam-free installation and excellent concentricity. The surface of the annular guide shaft is finely polished to ensure smooth sliding and flexible response during disc spring compression and rebound, reducing energy loss and wear. A carefully designed contraction groove on one edge of the guide pad not only provides ample space for changes in the disc spring shaft diameter but also allows for moderate deformation to buffer stress under load, ensuring the shaft diameter dynamically and precisely adjusts with the disc spring's inner hole, maintaining a tight and stable contact, and preventing relative displacement and jamming.

[0061] In the technical solution of this application, the nuts used for bolt fastening on the front end plate or rear end plate can be injection molded integrally by pre-embedding. Specifically, during the injection molding process of the end plate (such as the front end plate or rear end plate), the nuts are pre-embedded into the mold, so that the final molded end plate already contains these nuts. This design makes it easy to directly screw bolts into the pre-embedded nuts when fixing them later, thereby achieving the fastening of the hydrogen fuel cell stack assembly. This reduces the need for additional nut installation steps during subsequent assembly, improves production efficiency, and makes the connection between the nuts and the end plate more secure, thereby improving the stability and safety of the overall structure.

[0062] In an optional embodiment, a plurality of reinforcing ribs are provided on the other side of the pressure plate 9. These reinforcing ribs are used to locally reinforce the stress-bearing area of ​​the pressure plate 9, thereby improving its local stiffness and strength. In this embodiment, one side of the pressure plate 9 is tightly fitted to the rear end plate 7, while the other side has a plurality of reinforcing ribs. The layout of the reinforcing ribs can be determined through precise mechanical analysis, and is distributed according to the density of the stress on the pressure plate 9. The ribs are denser in areas bearing greater pressure and stress concentration, such as near the center of the fuel cell stack or fixed points, to reasonably distribute the overall stress to various local areas, avoiding stress concentration that could lead to deformation or damage, improving local stiffness and strength, and steadily maintaining the fuel cell stack structure. The reinforcing ribs and the pressure plate 9 are made of the same or compatible materials to ensure compatibility and synergistic effect in terms of physical and chemical properties. During manufacturing, the ribs are shaped by cutting and milling after molding, or by pre-setting the rib structure according to the mold in the injection molding and die casting integrated molding process. The material is filled and generated as a whole during molding. When the fuel cell stack is running, this structure provides stable support for the butterfly spring assembly 8, keeps the core pressure uniform and constant, and enables the fuel cell stack to operate reliably under complex working conditions and dynamic load changes.

[0063] In an optional embodiment, the outer periphery of the front end plate 1 and the rear end plate 7 are provided with equally spaced steel strip grooves 107; the battery stack also includes a number of steel strips 4, each of the steel strips 4 passes through the corresponding steel strip groove 107 and is wrapped around the outermost periphery of the hydrogen fuel cell stack to maintain the holding force of the hydrogen fuel cell stack. The steel strips 4 can be made of stainless steel.

[0064] Considering that uneven distribution of steel strips can lead to core stress imbalance and localized stress concentration, affecting battery performance and lifespan, this embodiment provides equally spaced steel strip grooves 107 on the outer periphery of the front end plate 1 and the rear end plate 7. Figure 3 Taking the front-end board 1 as an example, in the following explanation, Figure 3As can be seen, several equally spaced steel strip grooves are formed at corresponding positions on the upper and lower ends of the front end plate 1. Each steel strip groove has an arc-shaped surface. The equally spaced grooves ensure uniform distribution of the steel strip, maintaining a uniform distribution of the core's bearing force, balancing the core's stress, and reducing excessive local stress on the end plates. The arc-shaped steel strip grooves increase the effective contact area between the steel strip and the end plates, preventing steel strip failure due to excessive local stress at bends. The steel strip 4 can be made of stainless steel.

[0065] In an optional embodiment, a solid surface 22 for overall structural reinforcement is provided in the middle of the front end plate 1 structure; wherein the draft depth on the left and right sides of the solid surface is equal to reduce the deformation of the front end plate 1 caused by uneven thermal expansion and contraction after demolding; wherein a rectangular grid structure is provided on the left and right sides of the solid surface.

[0066] The applicant notes that the leakage of the core in existing hydrogen fuel cell stacks is mainly related to the stack's operating environment and structure. Specifically, in existing hydrogen fuel cell stacks, the core is exposed to the air. When gas seepage or leakage occurs between the cells during operation, liquid water droplets condense on the protective sheet. If these droplets contain impurities, they may cause short circuits between adjacent cells. To address this issue, in an optional embodiment of this application, the fuel cell stack may further include an upper protective plate 10 and a lower protective plate 11. Both the upper protective plate 10 and the lower protective plate 11 have a structure with uniformly distributed micropores. The upper protective plate 10 is positioned above the hydrogen fuel cell stack core, and the lower protective plate 11 is positioned below the hydrogen fuel cell stack core. The upper protective plate 10 and the lower protective plate 11 are used to improve electrical insulation strength and protect the hydrogen fuel cell stack core. Both the upper protective plate 10 and the lower protective plate 11 are made of insulating material. In this design, the upper protective plate 10 and the lower protective plate 11 can be made of materials with porous or microporous structures, which can isolate water droplets, allow air to pass through while providing insulation. This increases the electrical insulation strength between the steel strip and the hydrogen fuel cell stack core. It also allows the condensate droplets to be carried away by the purging gas through the micropores on the upper protective plate 10 and the lower protective plate 11 when there is leakage between multiple cells in the stack core or when the high-humidity purge gas condenses on the insulating sheet, or when the temperature of the hydrogen fuel cell stack core rises and the condensate droplets evaporate. This ultimately reduces the risk of short circuits between adjacent cells caused by condensate droplets.

[0067] In an optional embodiment, the fuel cell stack also includes a CVP harness 12 and a CVP connector 13. The CVP harness 12 and CVP connector 13 are connected for transmitting electrical signals and acquiring data. The CVP connector 13 connects the first CVP insert 14 and the CVP harness 12 to achieve electrical signal conduction. In the proton exchange membrane fuel cell stack structure, the CVP harness 12, as the core carrier for signal transmission, can be carefully twisted from multiple strands of wires with excellent conductivity. Its insulating outer sheath is tightly wrapped with a highly insulating, wear-resistant, and chemically corrosion-resistant material to ensure the stability and safety of signal transmission and effectively prevent signal interference and leakage. The CVP connector 13 is the pivotal component for achieving precise electrical signal conduction. Its internal structure includes multiple precisely designed metal contacts or pins, which are meticulously manufactured and precisely assembled according to strict electrical standards and tolerance requirements. During the connection process, the CVP connector 13, with its robust and reliable mechanical structure, ensures a tight, secure, and durable connection with the first CVP insert 14 and the CVP harness 12. This establishes a continuous, stable, and low-impedance transmission channel for electrical signals, effectively guaranteeing minimal signal loss and extremely high fidelity during transmission. During actual operation of the fuel cell stack, the CVP harness 12 and CVP connector 13 work closely together to efficiently collect and transmit electrical signals and data from various parts of the stack. These signals and data include key parameters such as voltage, current, and temperature of individual cells, providing crucial information for real-time monitoring of the stack's operating status. Utilizing advanced sensor technology and a sophisticated data acquisition system, relevant parameters can be collected and transmitted accurately in real-time with extremely high precision and frequency, providing solid data support for subsequent data analysis, fault diagnosis, and operational optimization. This mechanism allows for timely detection of abnormal conditions during stack operation, such as voltage fluctuations, current imbalances, and temperature exceeding limits. Based on this, targeted measures can be quickly taken for precise control and optimization, effectively ensuring the stack maintains a highly efficient, stable, and safe operating state.

[0068] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention 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 invention.

[0069] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0070] The above description is merely a specific embodiment of the invention, but the scope of protection of the invention is not limited thereto. Any variations or substitutions conceived without inventive effort should be included within the scope of protection of the invention. Therefore, the scope of protection of the invention should be determined by the scope defined in the claims.

Claims

1. A proton exchange membrane fuel cell stack, characterized in that, The battery stack includes: Front end plate (1), front current collector plate (2), tail end plate bipolar plate (3), proton exchange membrane electrode (5), hydrogen fuel cell stack core (6), rear end plate (7), several butterfly spring assemblies (8), pressure plate (9), first CVP insert (14), second CVP insert and rear current collector plate (15). The front end plate (1) is located at the front end of the hydrogen fuel cell stack. The outer end of the front end plate (1) is provided with a fuel gas hydrogen chamber inlet (101), a hydrogen chamber outlet after reaction (104), an auxiliary combustion gas air chamber inlet (102), an auxiliary combustion gas air chamber outlet after reaction (105), a cooling medium coolant inlet (103), and a coolant outlet after heat exchange (106). The front end plate (1) is obtained by injection molding using resin material as the base material; the upper end of the front end plate (1) is provided with a first nut (108) for fastening with the first bolt by pre-embedding, and the first nut (108) is integrally formed with the front end plate (1) during the injection molding process by pre-embedding. The front current collector (2) is made of conductive material. The main body of the front current collector (2) is a first plate-shaped structure (201). A first electrode (202) is integrally provided at the middle position of the upper end of the first plate-shaped structure (201). The first electrode (202) and the first plate-shaped structure (201) are orthogonally arranged. A plurality of first through holes (2021) are provided on the first electrode (202). After the first bolt is screwed into the first through hole (2021) and tightened with the pre-embedded first nut (108), the front current collector (2) is fixed to the front end plate (1). The plate-shaped structure of the front current collector (2) is close to the inner end of the front end plate (1). The hydrogen fuel cell stack (6) is disposed at the rear end of the front current collector (2). The hydrogen fuel cell stack (6) is composed of multiple single cells stacked together. A front tail plate bipolar plate (3) is disposed at the front end of the hydrogen fuel cell stack (6), and a rear tail plate bipolar plate is disposed at the rear end of the hydrogen fuel cell stack (6). A first recess (301) is provided on the front tail plate bipolar plate (3) near the outer side. A first columnar boss (302) is provided in the middle of the first recess (301). The first CVP insert (14) The mounting part (1401) of the first cylindrical boss (302) is provided with a second through hole (1402). The size of the second through hole (1402) matches the size of the first cylindrical boss (302). The shape of the first recess (301) matches the shape of the mounting part (1401), so that after the first cylindrical boss (302) is inserted into the second through hole (1402), the mounting part (1401) and the first recess (301) are snapped together. The second CVP insert is fixedly provided on the bipolar plate of the rear tail plate. The hydrogen fuel cell stack (6) is composed of multiple sets of bipolar plates and the proton exchange membrane electrode (5) stacked together; The rear collector plate (15) is disposed behind the bipolar plate of the rear tail plate, and the rear end plate (7) is disposed behind the rear collector plate (15); wherein, the rear end plate (7) is obtained by injection molding with resin material as matrix; the upper end of the rear end plate is provided with a second nut for fastening with the second bolt by pre-embedding, and the second nut is integrally formed with the rear end plate (7) during the injection molding process by pre-embedding; the rear collector plate (15) is made of conductive material, and the main body of the rear collector plate (15) is a second plate-shaped structure, and a second electrode ear is integrally disposed at the middle position of the upper end of the second plate-shaped structure, and the second electrode ear is orthogonally arranged with the second plate-shaped structure; a plurality of second through holes are opened on the second electrode ear; after the second bolt is screwed into the second through hole and tightened with the pre-embedded second nut, the rear collector plate (15) and the rear end plate (7) are fixed, and the plate-shaped main body of the rear collector plate (15) is close to the inner end of the rear end plate (7); During the injection molding process, the rear end plate (7) has a plurality of second recesses (19) integrally injection molded on its outer end. Each of the plurality of second recesses (19) has a second columnar boss (16) injection molded in it. The second columnar boss (16) is used to limit the movement of the butterfly spring assembly (8). The butterfly spring assembly (8) includes a guide pad (81) and a plurality of disc springs (82). The guide pad (81) includes an integrally formed base (811) and an annular guide shaft (812). The guide pad (81) has a contraction opening (20) on one side of the axial direction. The inner diameter of the disc spring (82) matches the outer diameter of the annular guide shaft (812). The pressure plate (9) is provided behind the rear end plate (7). The side of the pressure plate (9) that is in contact with the rear end plate (7) is provided with a plurality of annular clearance grooves (17). The opening position of each of the plurality of annular clearance grooves (17) corresponds to the opening position of the second recess at the corresponding position. A third columnar boss (18) is provided in each of the plurality of annular clearance grooves. The third columnar boss (18) is used to extend into the opening at the upper end of the annular guide shaft (812) at the corresponding position.

2. The proton exchange membrane fuel cell stack according to claim 1, characterized in that, Several reinforcing ribs are provided on the other side of the pressure plate (9). The reinforcing ribs are used to locally strengthen the stress area of ​​the pressure plate (9) to improve the local stiffness and local strength of the pressure plate (9).

3. The proton exchange membrane fuel cell stack according to claim 2, characterized in that, The outer periphery of the front end plate (1) and the rear end plate (7) are provided with equally spaced steel strip grooves (107). The battery stack also includes several steel strips (4), each of which passes through a corresponding steel strip groove (107) and is wound around the outermost periphery of the hydrogen fuel cell stack to maintain the holding force of the hydrogen fuel cell stack. The steel strips (4) are made of stainless steel.

4. The proton exchange membrane fuel cell stack according to claim 1, characterized in that, The front end plate (1) structure has a solid surface in the middle for overall structural reinforcement; wherein the draft depth on the left and right sides of the solid surface is equal to reduce the deformation of the front end plate (1) caused by uneven thermal expansion and contraction after demolding; wherein a rectangular grid structure is provided on the left and right sides of the solid surface.

5. The proton exchange membrane fuel cell stack according to claim 1, characterized in that, The battery stack also includes an upper protective plate (10) and a lower protective plate (11), both of which have a structure with uniformly distributed micropores; the upper protective plate (10) is disposed above the hydrogen fuel cell stack core (6), and the lower protective plate (11) is disposed below the hydrogen fuel cell stack core (6); the upper protective plate (10) and the lower protective plate (11) are used to improve electrical insulation strength and protect the hydrogen fuel cell stack core (6); both the upper protective plate (10) and the lower protective plate (11) are made of insulating material.

6. The proton exchange membrane fuel cell stack according to claim 1, characterized in that, The battery stack also includes a CVP harness (12) and a CVP connector (13); wherein the CVP harness (12) is connected to the CVP connector (13) for transmitting electrical signals and data acquisition; the CVP connector (13) is used to enable electrical signal conduction between the first CVP insert (14) and the CVP harness (12).

7. The proton exchange membrane fuel cell stack according to claim 1, characterized in that, The front end plate (1) and the rear end plate (7) are provided with several grid structures at their outer ends during the injection molding process to reduce weight.

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