A flow battery stack assembly device and stack

Abstract

The utility model provides a kind of liquid flow battery stack assembly device and stack, belong to liquid flow battery field.The device includes two groups of same structure electric pile assembly unit, trapezoidal lead screw and fastening device, two groups of electric pile assembly unit are symmetrically arranged and are connected as a whole by trapezoidal lead screw, and each group of electric pile assembly unit includes end plate spring subassembly, first steel end plate, insulating plate, current collector plate, lower pull rod subassembly, upper pull rod subassembly and support block.The utility model designs end plate spring subassembly, eliminates the problem of the deformation and vibration or thermal expansion caused by long screw rod when pressing, and the increase of local contact resistance, guarantees the performance of electric pile;And adopt integral type tight stack structure, structure simplification, substantially reduce the number of end plate and power unit container overall weight, improve the electric pile power and container space utilization, reduce material and manufacturing cost;Upper and lower pull rod subassembly is positioned to battery unit and upper pull rod subassembly can be opened and closed, improve installation and maintenance efficiency.

Description

Technical Field

[0001] This utility model belongs to the field of flow battery technology, specifically relating to a flow battery stack assembly device and a flow battery stack. Background Technology

[0002] Clean energy sources such as solar, wind, and tidal power have been widely used in power generation, but their inherent intermittency, volatility, and randomness pose significant challenges to power grid operation. These unstable factors can cause problems such as grid frequency fluctuations and voltage deviations, directly affecting power quality and system reliability, and thus threatening the overall security of the power network. To effectively address this contradiction, the development of efficient energy storage technology has become an important support for modern power systems.

[0003] Energy storage systems can be divided into two major technical systems based on energy conversion principles: physical energy storage and chemical energy storage. Physical energy storage technologies mainly include three mature solutions: flywheel energy storage, which uses the kinetic energy of a rotating body to store energy; pumped hydro storage, which stores energy through potential energy conversion; and compressed air energy storage, which relies on the compression and release process of high-pressure gas. Chemical energy storage, on the other hand, is based on battery technology and has formed a diversified technical route including lead-acid batteries, lithium-ion batteries, flow batteries, and sodium-sulfur batteries.

[0004] Among numerous energy storage solutions, vanadium redox flow batteries (VRFB) exhibit significant technological advantages: their cycle life can exceed 10,000 cycles, their energy conversion efficiency exceeds 80%, their system design features modular scalability, they support deep discharge, and their maintenance costs are low. In practical applications, they can serve as supporting energy storage devices for intermittent power sources such as wind, solar, and hydropower, and can also undertake key functions such as grid peak shaving and load balancing, effectively improving the operational stability and dispatch flexibility of the power system. Therefore, they are considered an important technological choice for building new power systems.

[0005] The existing assembly sequence for vanadium redox flow battery stacks is as follows: end plate, insulating plate, current collector, bipolar plate, sealant, electrode frame, sealant, electrode, ion exchange membrane, electrode, sealant, electrode frame, sealant, bipolar plate, current collector, insulating plate, end plate, and spring. A screw passes through two end plates and the spring, and a nut is used to tighten the spring to ensure a certain degree of deformation. Each stack typically has up to 70 cells, requiring 10-40 springs and matching screws to provide uniform clamping force. However, depending on the user's requirements, a single power unit container in the system needs to hold 5-30 independent stacks, each requiring an independent end plate and fastening assembly. This technology has the following significant drawbacks:

[0006] (1) Redundancy structure and reliability issues: Traditional fuel cell stacks rely on a large number of screws and springs to work together to maintain the stability of the overall structure. In order to ensure the installation accuracy of the screws, the number of battery cells in the fuel cell stack should not exceed 70. The more battery cells there are, the longer the screws will be. When the screws are subjected to axial fuel cell stack clamping force, their ability to resist bending deformation (stiffness) will decrease. The screws are more likely to bend longitudinally and are prone to clamping force attenuation due to vibration or thermal expansion, resulting in increased local contact resistance and affecting the overall performance and life of the fuel cell stack. Furthermore, after the fuel cell stack is installed inside the container, the clamping force can only be adjusted after disassembly. Otherwise, the clamping force cannot be adjusted directly.

[0007] (2) Regarding the performance of the fuel cell stack, the existing fuel cell stacks adopt a multi-section assembly method. The end plates on both sides of the stack are flat plates made of steel or other materials. During the fastening and operation of the fuel cell stack, the end plates will deform outward under stress, causing the core components inside the stack to deform accordingly. This deformation will be transmitted to the core components inside the stack, causing their structural instability. The resulting structural inconsistency will reduce the stack efficiency and have a serious impact on the reliability of the system.

[0008] (3) As the number of fuel cell stacks increases, the number of end plates, springs and screws increases exponentially, resulting in higher material costs. At the same time, the multi-fuel cell stack layout requires repeated assembly of fasteners, further increasing labor and time costs.

[0009] (4) Traditional fuel cell stacks are large in size and weight. Each stack needs to be assembled separately and installed into the container one by one. Lifting equipment is required during installation, which increases safety risks and installation costs.

[0010] (5) Traditional independent stack design requires the reservation of assembly gap between adjacent stacks, and the end plates and fasteners of each stack occupy a lot of extra space, which limits the total capacity of the stack battery cells in the container and reduces the number of battery cells per unit volume.

[0011] (6) Traditional battery stack packaging process rigidly solidifies multiple single cell units into an indivisible whole. Even if a single cell unit fails (such as membrane damage or electrode corrosion), the entire battery stack module needs to be disassembled for repair or replacement. The entire stack also requires the use of lifting equipment when disassembling. Furthermore, the stack cannot be disassembled directly on the project site and needs to be transported back to the production base, increasing transportation, maintenance, and time costs. Utility Model Content

[0012] The purpose of this invention is to provide a flow battery stack assembly device that eliminates the problem of increased local contact resistance caused by deformation, vibration or thermal expansion of the long screw during clamping, ensures the performance of the stack, reduces the number of end plates and the overall weight of the power unit container, improves the stack power and container space utilization, enhances installation and maintenance efficiency, and reduces material and manufacturing costs.

[0013] To achieve the above objectives, this utility model provides a flow battery stack assembly device, including two sets of stack assembly units with identical structures, trapezoidal lead screws 8 and fastening devices 9. The two sets of stack assembly units are symmetrically arranged and connected into a whole by several trapezoidal lead screws 8. Each set of stack assembly units includes a first steel end plate 1, an insulating plate 2, a current collector 3, an upper pull rod assembly 4, a lower pull rod assembly 5, a support block 6 and an end plate spring assembly 7.

[0014] There are multiple pull-down rod assemblies 5, which are located on the same horizontal plane and have one end fixed to the lower part of the first steel end plate 1 and the other end fixed to the support block 6, for supporting and limiting the battery unit.

[0015] There are multiple support blocks 6, and the tops of the multiple support blocks 6 are respectively connected to the middle and end of the pull-down rod assembly 5 to support the pull-down rod assembly and prevent the pull-down rod assembly from generating bending moment due to large force, which would affect the performance of the battery.

[0016] There are multiple upper pull rod assemblies 4. The multiple upper pull rod assemblies 4 are openable rods arranged along the top of the first steel end plate 1 and located on the same horizontal plane, used to limit the battery unit; one end of the upper pull rod assembly 4 is fixed to the first steel end plate 1, and the other end is movably connected to the end plate spring assembly 7.

[0017] The end plate spring assembly 7 is disposed opposite to the first steel end plate 1 and is movably connected between the upper pull rod assembly 4 and the lower pull rod assembly 5;

[0018] The insulating plate 2 is connected to the inner wall of the first steel end plate 1; there are two current collectors 3 in total, and the two current collectors 3 are respectively connected to the inner wall of the insulating plate 2 and the inner wall of the end plate spring assembly 7.

[0019] The trapezoidal lead screw 8 is provided in two sets, with multiple screws in each set. The two ends of one set of trapezoidal lead screw 8 pass through the upper part of the end plate spring assembly 7 of the two sets of fuel cell stack assembly units and are screwed to the corresponding upper pull rod assembly 4. The two ends of the other set of trapezoidal lead screw 8 pass through the lower part of the end plate spring assembly 7 of the two sets of fuel cell stack assembly units and are screwed to the corresponding lower pull rod assembly 5.

[0020] The fastening device 9 is located on the outside of the end plate spring assembly 7 and is used to provide a clamping force to move the end plate spring assembly 7 along the upper pull rod assembly 4 and the lower pull rod assembly 5 to press the battery unit between the end plate spring assembly 7 and the first steel end plate 1, and to fix the end plate spring assembly 7 by means of nuts and each trapezoidal lead screw 8.

[0021] According to some embodiments of the present invention, a flow battery stack assembly device includes an upper pull rod assembly 4 comprising a screw fastener 41, an upper pull rod body 42, a first PTFE plate 43, and a nut fastener 44. The two ends of the upper pull rod body 42 are respectively fastened to the screw fastener 41 and the nut fastener 44, with a draft angle of 1° to 10° at the connection point. A screw is welded to the front end of the screw fastener 41, which is connected to the first steel end plate 1 in conjunction with a nut. The nut fastener 44 has internal threads that connect with a trapezoidal lead screw 8. The first PTFE plate 43 is mounted on the lower surface of the upper pull rod body 42.

[0022] According to some embodiments of the present invention, a flow battery stack assembly device includes a pull rod assembly 5 comprising a pull rod body 51 and a second PTFE plate 52; one end of the pull rod body 51 is welded with a screw, which is connected to the first steel end plate 1 in cooperation with a nut; the other end of the pull rod body 51 is internally threaded and is connected to a trapezoidal lead screw 8; the second PTFE plate 52 is mounted on the upper surface of the pull rod body 51.

[0023] According to some embodiments of the present invention, in a flow battery stack assembly device, each trapezoidal lead screw 8 has its left and right sides having opposite thread directions with the middle position as the reference, ensuring that the tie rods of the two sets of stack assembly units can be installed symmetrically at the same time.

[0024] According to some embodiments of the present invention, a flow battery stack assembly device includes an epoxy resin end plate 71, a spring 72, a second steel end plate 73, and an end plate bolt assembly 74. The outer wall of the epoxy resin end plate 71 is connected to a current collector 3. The inner wall of the epoxy resin end plate 71 and the inner wall of the second steel end plate 73 are provided with a plurality of spring countersunk holes opposite to each other. The spring 72 is installed in the spring countersunk holes, and the epoxy resin end plate 71, the second steel end plate 73, and the spring 72 between them are fixedly clamped by the end plate bolt assembly 74.

[0025] According to some embodiments of the present invention, a flow battery stack assembly device has several first slots on the top edge of the epoxy resin end plate 71, and the upper pull rod assembly 4 is movably connected to the first slots and can slide relative to each other along the first slots; the bottom edge of the epoxy resin end plate 71 has several second slots, and the lower pull rod assembly 5 is movably connected to the second slots and can slide relative to each other along the second slots; the second steel end plate 73 is provided with several through holes for the trapezoidal lead screw 8 to pass through, and the through holes are clearance-fitted with the trapezoidal lead screw 8.

[0026] According to some embodiments of the present invention, in a flow battery stack assembly device, the thickness of the first steel end plate 1 is 50-80mm; the thickness of the epoxy resin end plate 71 is 30-35mm, preferably 30mm.

[0027] According to some embodiments of the present invention, a flow battery stack assembly device includes a fastening device 9 using a jack, and an end plate spring assembly 7 further including an anti-deformation pad 75, a jack support plate 76, and a pad bolt assembly 77. The anti-deformation pad 75 is connected to the middle of the outer wall of the second steel end plate 73 via the pad bolt assembly 77 to prevent uneven force distribution when the jack directly contacts the second steel end plate during clamping. The jack support plate 76 is located in the middle of the anti-deformation pad 75 and is used to place the jack to ensure that the jack does not become eccentric during use.

[0028] According to some embodiments of the present invention, in a flow battery stack assembly device, the length ratio of the second steel end plate 73 to the length of the anti-deformation pad 75 is 2 to 2.5.

[0029] According to some embodiments of the present invention, a flow battery stack assembly device is provided, wherein the fastening device 9 adopts a worm gear reducer, the worm gear reducer is used in conjunction with a trapezoidal lead screw 8, a single-headed worm is designed in the middle position of the trapezoidal lead screw 8, and a threaded hole is provided on the second steel end plate 73, and the trapezoidal lead screw 8 is threadedly connected to the threaded hole.

[0030] According to some embodiments of the present invention, a flow battery stack assembly device further includes a displacement sensor 10, which is disposed inside the epoxy resin end plate 71. The displacement sensor 10 monitors the spring elongation by monitoring the displacement of the second steel end plate 73 during long-term operation. When the spring elongation exceeds the set value, an alarm is triggered to facilitate timely maintenance.

[0031] This utility model also provides a battery stack, including a plurality of battery cells and the above-mentioned flow battery stack assembly device.

[0032] Compared with the prior art, the beneficial effects of this utility model are:

[0033] 1) Simplified Structure and Enhanced Reliability: The screwless design eliminates the problem of increased local contact resistance caused by deformation, vibration, or thermal expansion of long screws during clamping. Contact resistance fluctuation is reduced by 20%-30%, and the stack cycle life is extended by more than 20%. Combined with a new double-end plate structure, elastic support is built for the middle position of the end plate, which significantly improves the bending stiffness of the end plate and effectively reduces the out-of-plane buckling deformation in the central area caused by non-uniform clamping force field from 1.6mm to less than 0.7mm. This ensures uniform stress on the internal components of the stack and guarantees the continuous stability of the stack performance. Furthermore, the simplified structure reduces the number of rear end plates by more than 90%, and the overall weight of the power unit container is reduced by at least 40%.

[0034] 2) Significantly increased battery stack power: The integrated compact stack structure allows the battery stack to hold at least 200 battery cells with only a few end plates and 20-40 springs, significantly increasing the battery stack power per unit volume by at least 5%.

[0035] 3) Increased space utilization: By adopting a clustered integrated design for the fuel cell stack, the redundant endplate structure and assembly buffer gaps between units of traditional independent fuel cell stack units are completely eliminated. Optimized calculations show that the effective loading volume within a single container increases by 21.7%.

[0036] 4) Significantly improved installation and maintenance efficiency: Battery units can be placed individually in the overall assembly device, eliminating the need to assemble individual battery stacks one by one, thus improving installation efficiency by more than 60%; during later maintenance, a single faulty unit can be directly replaced by opening the upper pull rod assembly, eliminating the need for replacing the entire stack, reducing maintenance time and significantly lowering operation and maintenance costs. Attached Figure Description

[0037] Figure 1 This is an isometric schematic diagram of a flow battery stack assembly device according to an embodiment of this utility model.

[0038] Figure 2 This is a schematic diagram of the upper pull rod assembly in an embodiment of the present invention; wherein (a) is an overall structural diagram and (b) is an assembly diagram.

[0039] Figure 3 This is a schematic diagram of the pull rod assembly structure in an embodiment of this utility model.

[0040] Figure 4 This is a schematic diagram of the end plate spring assembly structure in an embodiment of the present invention; wherein (a) is the assembly front view and (b) is the assembly exploded view.

[0041] Figure 5 This is a fastening device for the worm gear reducer in this embodiment of the utility model.

[0042] Figure 6This is a stress analysis diagram of the existing fuel cell stack endplate.

[0043] Figure 7 This is a diagram showing the layout and force analysis of the end plate springs in an embodiment of this utility model; where (a) is the layout of the epoxy resin end plate springs and (b) is the force analysis of the epoxy resin end plate.

[0044] Figure 8 This is a comparative example of the epoxy resin end plate spring layout analysis diagram; where (a), (b), (c), and (d) are schematic diagrams of different spring layouts on the epoxy resin end plate, respectively.

[0045] Figure 9 These are finite element analysis diagrams of the second steel end plate and the anti-deformation pad under stress; where (a) and (b) are the front view and top view of the mechanical analysis of the second steel end plate without the anti-deformation pad, respectively, and (c) and (d) are the front view and top view of the mechanical analysis of the second steel end plate after the anti-deformation pad is installed, respectively.

[0046] Figure 10 These are the mechanical finite element analysis diagrams of the pull rod assembly under stress; where (a) is the mechanical finite element analysis diagram of the pull rod assembly without support blocks, and (b) is the mechanical finite element analysis diagram of the pull rod assembly with support blocks.

[0047] In the diagram: 1 First steel end plate; 2 Insulating plate; 3 Current collector; 4 Upper pull rod assembly; 5 Lower pull rod assembly; 6 Support block; 7 End plate spring assembly; 8 Trapezoidal lead screw; 9 Fastening device; 10 Displacement sensor; 11 Battery unit; 12 Worm gear reducer; 41 Screw fastener; 42 Upper pull rod body; 43 First PTFE plate; 44 Nut fastener; 51 Lower pull rod body; 52 Second PTFE plate; 71 Epoxy resin end plate; 72 Spring; 73 Second steel end plate; 74 End plate bolt assembly; 75 Anti-deformation pad; 76 Jack support plate; 77 Pad bolt assembly. Detailed Implementation

[0048] The principles and features of this utility model are described below with reference to the accompanying drawings. The examples given are only for explaining this utility model and are not intended to limit the scope of this utility model.

[0049] This embodiment provides a flow battery stack assembly device, such as... Figure 1 As shown, it includes two sets of identical fuel cell stack assembly units, trapezoidal lead screws 8 and fastening devices 9. The two sets of fuel cell stack assembly units are symmetrically arranged and connected into a whole by several trapezoidal lead screws 8. Each set of fuel cell stack assembly units includes a first steel end plate 1, an insulating plate 2, a current collector 3, an upper pull rod assembly 4, a lower pull rod assembly 5, a support block 6 and an end plate spring assembly 7.

[0050] There are multiple pull rod assemblies 5, which are located on the same horizontal plane and have one end fixed to the lower part of the first steel end plate 1 and the other end fixed to the support block 6, for supporting and limiting the battery unit.

[0051] There are multiple support blocks 6, and the tops of the multiple support blocks 6 are respectively connected to the middle and end of the pull rod assembly 5 to support the pull rod assembly and prevent the pull rod assembly from generating bending moment due to large force, which would affect the performance of the battery.

[0052] There are multiple upper pull rod assemblies 4. The multiple upper pull rod assemblies 4 are openable rods arranged along the top of the first steel end plate 1 and located on the same horizontal plane, used to limit the battery unit; one end of the upper pull rod assembly 4 is fixed on the first steel end plate 1, and the other end is movably connected to the end plate spring assembly 7.

[0053] The end plate spring assembly 7 is disposed opposite to the first steel end plate 1 and is movably connected between the upper pull rod assembly 4 and the lower pull rod assembly 5;

[0054] The insulating plate 2 is connected to the inner wall of the first steel end plate 1; there are two current collectors 3, and the two current collectors 3 are respectively connected to the inner wall of the insulating plate 2 and the inner wall of the end plate spring assembly 7.

[0055] Two sets of trapezoidal lead screws 8 are provided, with multiple sets in each set. The two ends of one set of trapezoidal lead screws 8 pass through the upper part of the end plate spring assembly 7 of the two sets of fuel cell stack assembly units and are screwed to the corresponding upper pull rod assembly 4. The two ends of the other set of trapezoidal lead screws 8 pass through the lower part of the end plate spring assembly 7 of the two sets of fuel cell stack assembly units and are screwed to the corresponding lower pull rod assembly 5.

[0056] The fastening device 9 is located on the outside of the end plate spring assembly 7 and is used to provide clamping force to move the end plate spring assembly 7 along the upper pull rod assembly 4 and the lower pull rod assembly 5 to press the battery unit between the end plate spring assembly 7 and the first steel end plate 1, and fix the position of the end plate spring assembly 7 by cooperating with each trapezoidal lead screw 8 through the nut.

[0057] Specifically, the end plate spring assembly 7 includes an epoxy resin end plate 71, a spring 72, a second steel end plate 73, and an end plate bolt assembly 74. The inner walls of the epoxy resin end plate 71 and the second steel end plate 73 are provided with several countersunk spring holes facing each other. The spring 72 is installed in the countersunk spring holes, and the epoxy resin end plate 71, the second steel end plate 73, and the spring 72 between them are fixedly clamped together by the four end plate bolt assemblies 74. Figure 1 and Figure 4As shown in (b), the top edge of the epoxy resin end plate 71 has three first slots, and the upper pull rod assembly 4 is movably connected to the first slots and can slide along the first slots; the bottom edge of the epoxy resin end plate 71 has three second slots, and the lower pull rod assembly 5 is movably connected to the second slots and can slide along the second slots; the second steel end plate 73 is provided with through holes for the trapezoidal lead screw 8 to pass through at the positions corresponding to the six slots, and the through holes are clearance-fitted with the trapezoidal lead screw 8.

[0058] A displacement sensor 10 is installed on the inner side of the epoxy resin end plate 71. The spring elongation is monitored by monitoring the displacement of the second steel end plate 73 during long-term operation. An alarm is triggered when the spring elongation exceeds the set value, which facilitates timely maintenance.

[0059] The first steel end plate 1 is installed inside the container and is positioned opposite to the epoxy resin end plate 71 of the end plate spring assembly 7; the insulating plate 2 is connected to the inner wall of the first steel end plate 1 by screws; the two current collectors 3 are respectively connected to the inner wall of the insulating plate 2 and the inner wall of the epoxy resin end plate 71 by screws.

[0060] like Figure 1 As shown, three pull-down rod assemblies 5 are provided, and the three pull-down rod assemblies 5 are evenly distributed along the length direction of the first steel end plate 1. The battery units 11 are arranged sequentially on the pull-down rod assemblies 5. Figure 3 As shown, each pull rod assembly 5 includes a pull rod body 51 and a second PTFE plate 52; one end of the pull rod body 51 is welded with a screw, which is connected to the first steel end plate 1 in conjunction with a nut; the other end of the pull rod body 51 is fixed to the top of the support block 6 and has an internal thread machined at the end, which is connected to the trapezoidal lead screw 8 passing through the second steel end plate 73; the second PTFE plate 52 is installed on the upper surface of the pull rod body 51.

[0061] like Figure 1 As shown, the tops of multiple support blocks 6 are respectively connected to the middle and end of the pull rod assembly 5, and the bottom surface of the support block 6 is kept horizontal with the bottom surface of the first steel end plate 1 to ensure the overall stability of the structure.

[0062] like Figure 2 As shown, three upper pull rod assemblies 4 are provided. Each upper pull rod assembly 4 includes a screw fastener 41, an upper pull rod body 42, a first PTFE plate 43, and a nut fastener 44. The screw fastener 41 and the nut fastener 44 are machined with slots. The upper pull rod body 42 has structures at both ends that mate with the slots, and are connected to the screw fastener 41 and the nut fastener 44 by fastening. The connection is designed with a draft angle of 1° to 10°. A screw is welded to the front end of the screw fastener 41 and is connected to the first steel end plate 1 with a nut. The nut fastener 44 has internal threads and is connected to the trapezoidal lead screw 8 that passes through the second steel end plate 73. The first PTFE plate 43 is installed on the lower surface of the upper pull rod body 42.

[0063] The upper pull rod assembly 4 is placed on the first groove on the upper edge of the epoxy resin end plate 71, and the second groove on the lower edge of the epoxy resin end plate 71 is placed on the lower pull rod assembly 5. The end plate spring assembly 7 can move smoothly along the upper pull rod assembly 4 and the lower pull rod assembly 5, encapsulating the battery unit between it and the first steel end plate 1, as well as the upper pull rod assembly 4 and the lower pull rod assembly 5. The position of the end plate spring assembly 7 is fixed by the cooperation of the nuts with each trapezoidal lead screw 8.

[0064] Each trapezoidal lead screw 8 is based on the middle position, with the left and right sides having opposite spiral directions, ensuring that it can be installed symmetrically with the tie rods of the two sets of fuel cell stack assembly units at the same time.

[0065] The fastening device 9 includes a mechanical jack, a hydraulic jack, or a worm gear reducer.

[0066] When the fastening device 9 uses a jack, the end plate spring assembly 7 also includes an anti-deformation pad 75, a jack support plate 76, and a pad bolt assembly 77. The anti-deformation pad 75 has a concave design and is connected to the middle of the outer wall of the second steel end plate 73 by four pad bolt assemblies 77 to prevent the jack from directly contacting the second steel end plate and causing uneven force during clamping. The jack support plate 76 is located in the middle of the anti-deformation pad 75 and is used to place the jack to ensure that the jack does not become eccentric during use.

[0067] When the fastening device 9 uses a worm gear reducer to achieve precise displacement control, such as Figure 5 As shown, the worm gear reducer 12 is used in conjunction with the trapezoidal lead screw 8. The trapezoidal lead screw 8 has a single-headed worm at the middle position and a threaded hole on the second steel end plate 73. The trapezoidal lead screw 8 is threadedly connected to the threaded hole.

[0068] This utility model embodiment also provides a battery stack, including a plurality of battery cells and the above-described flow battery stack assembly device.

[0069] like Figure 6 The diagram shows the stress analysis of the existing fuel cell stack endplate. The endplate is 1100 mm long, 570 mm wide, and 30 mm thick. The material has a tensile strength of 235 MPa and a bending strength of 215 MPa. Its inner side is supported by the core component, while its outer perimeter is subjected to the locking force of fasteners. The opposing forces from both sides cause deformation of the endplate, manifested as an outward bulge in the central area. Simulation calculations show that the maximum deformation of the central bulge is 1.56 mm, and the central stress is 190 MPa.

[0070] like Figure 7This diagram illustrates the layout and force analysis of the epoxy resin end plate springs in the novel structure of this embodiment. By integrating a pre-compression spring array between the relatively disposed epoxy resin end plate 71 and the second steel end plate 73, elastic support is constructed for the midpoint between the epoxy resin end plate 71 and the second steel end plate 73. Figure 7 (a) The epoxy resin end plate has a length of 900 mm, a width of 450 mm, a thickness of 30 mm, a tensile strength of 90 MPa, and a bending strength of 120 MPa. Seven springs are evenly spaced along its upper and lower edges to form a rigid frame to bear the boundary load. In the middle row, only one spring is placed at the center of each of the left and right ends of the epoxy resin end plate to create an elastic transition zone to guide force flow and avoid stress concentration. Two springs are placed on each side of the focal row at the center of the epoxy resin end plate to control core deformation and reserve space for stress release. According to the simulation analysis results, the central deformation of the epoxy resin end plate is 0.7 mm, and the central stress is 82 MPa. The results show that this design significantly improves the bending stiffness of the end plate and effectively reduces the out-of-plane buckling deformation in the central area caused by the non-uniform clamping force field, thereby greatly reducing the risk caused by uneven internal contact stress distribution due to end plate deflection.

[0071] like Figure 8 This is a comparative example diagram of the epoxy resin end plate spring layout of this utility model. The epoxy resin end plate has a length of 900mm, a width of 450mm, a thickness of 30mm, a tensile strength of 90MPa, and a bending strength of 120MPa. (As shown...) Figure 8 The layout shown in (a) involves evenly distributing seven springs along the upper and lower edges and the middle row of the epoxy resin end plate. Theoretically, this can initially disperse the load borne by the end plate and maintain in-plane force balance to a certain extent. However, in actual working conditions, this "functional superposition" layout ignores the mechanical transmission logic and structural adaptability of the end plate. Under complex loads, it is prone to local overload, premature failure of the end plate or springs, and overall stability and reliability are affected. Simulation calculations show that the center deformation of the end plate is 1.4 mm and the stress is 151.9 MPa. Figure 8 The layout schemes shown in (b), (c), and (d) all employ a planar cover to balance the load and utilize the symmetry of the row and column arrangement to initially guide the uniform transmission of force flow, theoretically providing some support to the end plate and mitigating deformation. However, their layout logic and the mechanical properties of the end plate are not well-matched: on the one hand, the excessively dense spring arrangement (such as a partially full-coverage layout) results in stiffness redundancy, strong mechanical coupling between adjacent springs, which easily leads to mutual interference of internal stresses and a chain reaction of single spring failures, while also increasing cost and installation complexity; on the other hand, the unevenly distributed intermediate layout disrupts the continuity of force flow in the end plate, failing to accurately bear the load transfer, resulting in local stress concentration and an imbalance in stiffness matching between the boundary and the center. Simulation calculations... Figure 8 (b) The central deformation of the scheme shown is 1.8 mm, and the stress is 190.8 MPa. Figure 8 In scheme (c), the central deformation is 1.6 mm and the stress is 175.6 MPa. Figure 8 The central deformation of the scheme shown in (d) is 0.9 mm, and the stress is 108 MPa.

[0072] Depend on Figure 9 The simulation analysis diagram shows that the deformation of the second steel end plate 73 under stress is 4.68 mm. Adding the anti-deformation pad 75, which has a concave design to disperse stress concentration on the jack, results in an overall deformation of 1.48 mm under stress after the anti-deformation pad is installed. Furthermore, the color scale indicates that there are no stress concentration points on the end plate, demonstrating that the anti-deformation pad effectively distributes force evenly.

[0073] Depend on Figure 10 The simulation analysis diagram shows that the maximum deformation of the pull rod assembly 5 without support is about 1.35 mm. After adding the support block 6, the deformation is reduced to 0.06 mm, which improves the stability of the fuel cell stack during operation.

[0074] The embodiments of this utility model are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the utility model to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical applications of this utility model, and to enable those skilled in the art to understand this utility model and design various embodiments with various modifications suitable for a particular purpose.

Claims

1. A flow battery stack assembly device, characterized in that, It includes two sets of identical fuel cell stack assembly units, trapezoidal lead screws (8) and fastening devices (9). The two sets of fuel cell stack assembly units are symmetrically arranged and connected as a whole by several trapezoidal lead screws (8). Each set of fuel cell stack assembly units includes a first steel end plate (1), an insulating plate (2), a current collector plate (3), an upper pull rod assembly (4), a lower pull rod assembly (5), a support block (6) and an end plate spring assembly (7). There are multiple pull rod assemblies (5), and the multiple pull rod assemblies (5) are located on the same horizontal plane. One end is fixed to the lower part of the first steel end plate (1), and the other end is fixed to the support block (6) for bearing and limiting the battery unit. There are multiple support blocks (6), and the tops of the multiple support blocks (6) are respectively connected to the middle and end of the pull-down rod assembly (5) to support the pull-down rod assembly; There are multiple upper pull rod assemblies (4). Each upper pull rod assembly (4) is an openable rod body arranged along the top of the first steel end plate (1) and located on the same horizontal plane, used to limit the battery unit. One end of the upper pull rod assembly (4) is fixed on the first steel end plate (1), and the other end is movably connected to the end plate spring assembly (7). The end plate spring assembly (7) is disposed opposite to the first steel end plate (1) and is movably connected between the upper pull rod assembly (4) and the lower pull rod assembly (5); The insulating plate (2) is connected to the inner wall of the first steel end plate (1); there are two current collectors (3), and the two current collectors (3) are respectively connected to the inner wall of the insulating plate (2) and the inner wall of the end plate spring assembly (7); The trapezoidal lead screw (8) is provided in two sets, with multiple screws in each set. The two ends of one set of trapezoidal lead screw (8) pass through the upper part of the end plate spring assembly (7) of the two sets of fuel cell stack assembly units and are screwed to the corresponding upper pull rod assembly (4). The two ends of the other set of trapezoidal lead screw (8) pass through the lower part of the end plate spring assembly (7) of the two sets of fuel cell stack assembly units and are screwed to the corresponding lower pull rod assembly (5). The fastening device (9) is located on the outside of the end plate spring assembly (7) and is used to provide a clamping force to make the end plate spring assembly (7) move along the upper pull rod assembly (4) and the lower pull rod assembly (5) to press the battery unit between the end plate spring assembly (7) and the first steel end plate (1), and fix the end plate spring assembly (7) by cooperating with each trapezoidal screw (8) through a nut.

2. The flow battery stack assembly device according to claim 1, characterized in that, The upper pull rod assembly (4) includes a screw fastener (41), an upper pull rod body (42), a first PTFE plate (43), and a nut fastener (44). The two ends of the upper pull rod body (42) are connected to the screw fastener (41) and the nut fastener (44) respectively by fastening. The connection is designed with a draft angle of 1°~10°. The screw fastener (41) has a screw welded to its front end, which is connected to the first steel end plate (1) in cooperation with the nut. The nut fastener (44) has a thread inside, which is connected to the trapezoidal lead screw (8). The first PTFE plate (43) is installed on the lower surface of the upper pull rod body (42).

3. The flow battery stack assembly device according to claim 1, characterized in that, The pull rod assembly (5) includes a pull rod body (51) and a second PTFE plate (52); one end of the pull rod body (51) is welded with a screw, which is connected to the first steel end plate (1) in cooperation with a nut; the other end of the pull rod body (51) is internally threaded and connected to the trapezoidal lead screw (8); the second PTFE plate (52) is installed on the upper surface of the pull rod body (51).

4. The flow battery stack assembly device according to claim 1, characterized in that, Each trapezoidal lead screw (8) has its left and right threads in opposite directions, with the middle position as the reference.

5. The flow battery stack assembly device according to claim 1, characterized in that, The end plate spring assembly (7) includes an epoxy resin end plate (71), a spring (72), a second steel end plate (73), and an end plate bolt assembly (74); the outer wall of the epoxy resin end plate (71) is connected to a manifold (3); the inner wall of the epoxy resin end plate (71) and the inner wall of the second steel end plate (73) are provided with a plurality of spring countersunk holes opposite to each other, the spring (72) is installed in the spring countersunk holes, and the epoxy resin end plate (71), the second steel end plate (73), and the spring (72) between them are fixedly clamped by the end plate bolt assembly (74).

6. The flow battery stack assembly device according to claim 5, characterized in that, The first steel end plate (1) has a thickness of 50~80mm; the epoxy resin end plate (71) has a thickness of 30~35mm; the top edge of the epoxy resin end plate (71) has several first slots, the upper pull rod assembly (4) is movably connected to the first slots and can slide relative to each other along the first slots; the bottom edge of the epoxy resin end plate (71) has several second slots, the lower pull rod assembly (5) is movably connected to the second slots and can slide relative to each other along the second slots; the second steel end plate (73) is provided with several through holes for the trapezoidal lead screw (8) to pass through, and the through holes are clearance-fitted with the trapezoidal lead screw (8).

7. The flow battery stack assembly device according to claim 5, characterized in that, The fastening device (9) uses a jack, and the end plate spring assembly (7) also includes an anti-deformation pad (75), a jack support plate (76), and a pad bolt assembly (77); the anti-deformation pad (75) is connected to the middle of the outer wall of the second steel end plate (73) through the pad bolt assembly (77), and the length ratio of the second steel end plate (73) to the length of the anti-deformation pad (75) is 2~2.5; the jack support plate (76) is located in the middle of the anti-deformation pad (75) and is used to place the jack.

8. The flow battery stack assembly device according to claim 5, characterized in that, The fastening device (9) adopts a worm gear reducer. The worm gear reducer is used in conjunction with the trapezoidal screw (8). The trapezoidal screw (8) has a single-headed worm at the middle position and a threaded hole is provided on the second steel end plate (73). The trapezoidal screw (8) is threadedly connected to the threaded hole.

9. A flow battery stack assembly device according to claim 5, characterized in that, The fuel cell assembly device also includes a displacement sensor (10), which is located inside the epoxy resin end plate (71) and monitors the elongation of the spring by monitoring the displacement of the second steel end plate (73) during long-term operation.

10. A fuel cell stack, characterized in that, It includes several battery cells and a flow battery stack assembly device as described in any one of claims 1-9.

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