Electric pile structure

Abstract

The utility model discloses a galvanic pile structure. The galvanic pile structure comprises a battery and an end plate, the number of the batteries is multiple, and the multiple batteries are arranged in a stacked mode. The number of the end plates is at least two, and the end plates are respectively arranged at two ends of the plurality of batteries; a plurality of fastening bolts are connected between the end plates, and the fastening bolts are connected with the end plates to clamp the battery; the plurality of fastening bolts are divided into two groups, and the two groups of fastening bolts are respectively positioned on one group of opposite side edges of the end plate; and the end plate has initial deflection opposite to the direction of the battery from the central axis to the two side edges connected with the fastening bolts. By arranging the end plates with initial deflection, the stress uniformity of the battery is improved, the electrochemical reaction uniformity of the battery is higher, the working efficiency of the galvanic pile is improved, the problem of structural damage can be reduced, and the service life is prolonged.

Description

Technical Field

[0001] The present application relates to the technical field of electrochemistry, and in particular to a battery stack structure. Background Art

[0002] End plates are used in electrochemical equipment such as fuel cells and electrolyzer stacks to apply preload to the battery. Sufficient preload is applied to ensure overall sealing performance and reduce interface contact resistance.

[0003] In the related art, the end plate is fixed and pre-tightened, and the main method is to use pre-tightening bolts to surround the edge of the end plate. In the process of applying the pre-tightening force to the end plate, the end plate will inevitably deform, causing the force applied by the end plate on the battery to be uneven, which will cause flow resistance, resistance differences, interface reaction rate differences, etc., resulting in local uneven reaction problems, resulting in reduced working efficiency and shortened life of the fuel cell and electrolyzer stack. Utility Model Content

[0004] In view of this, the purpose of this application is to provide a battery stack structure to overcome the problem of uneven pre-tightening force applied to the battery due to deformation of the end plate in the existing technology, improve the uniformity of the reactions of various parts of the battery, improve the working efficiency of the fuel cell and electrolyzer stack, and extend the service life.

[0005] To achieve at least one of the above objectives, this application provides the following technical solutions:

[0006] An embodiment of the present application provides a battery stack structure, including batteries and end plates;

[0007] There are multiple batteries, and the multiple batteries are stacked and arranged;

[0008] There are at least two end plates, which are respectively arranged at both ends of the plurality of batteries;

[0009] A plurality of fastening bolts are connected between the end plates, and the fastening bolts are connected to the end plates to clamp the battery;

[0010] The plurality of fastening bolts are divided into two groups, and the two groups of fastening bolts are respectively located on opposite sides of one group of the end plates;

[0011] The end plates have an initial deflection from the central axis to the two side edges connected with the fastening bolts in the direction away from the battery.

[0012] In some embodiments, the initial deflection gradually increases from the center axis of the end plate toward the two side edges connected by the fastening bolts.

[0013] In some embodiments, when the fastening bolt applies a set pre-tightening force to the end plate, the surface of the end plate facing the battery is parallel to the surface of the battery facing the end plate.

[0014] In some embodiments, the end plate is rectangular;

[0015] The two groups of fastening bolts are respectively arranged along the two long sides of the end plate.

[0016] In some embodiments, the initial deflection of the end plate satisfies the following relationship:

[0017]

[0018] The initial deflection of the end plate is equal to δ;

[0019] in, P = qbL1;

[0020] E is the Young's modulus of the end plate material;

[0021] L1 is the size of the battery in the first direction

[0022] L2 is the vertical distance in the first direction between the forces applied by the two sets of fastening bolts on the end plate.

[0023] b is the distance between two adjacent fastening bolts in the same group;

[0024] h is the thickness of the end plate;

[0025] x is the distance from the symmetry plane of the two sets of fastening bolts;

[0026] P is the load applied by each of the fastening bolts to the end plate;

[0027] q is the uniformly distributed load between the battery and the end plate;

[0028] The first direction is the arrangement direction of the two sets of fastening bolts.

[0029] In some embodiments, a positioning piece is provided on the end plate, and the side surface of the battery is in contact with the positioning piece to define the position of the battery relative to the end plate;

[0030] There are at least two positioning members, two of which are respectively used to abut against two adjacent side surfaces of the battery.

[0031] In some embodiments, the positioning member includes a connecting plate and a positioning plate disposed on the connecting plate;

[0032] The connecting plate is connected to the end plate;

[0033] A clearance groove is provided on the end plate, and the positioning plate is located in the clearance groove in the pre-tightened state. When the end plate has an initial deflection state, the end of the positioning plate away from the connecting plate protrudes from the clearance groove to the surface of the end plate facing the battery side.

[0034] In some embodiments, a plug-in slot is provided on the end plate, and the connecting plate is inserted into the plug-in slot and fixed relative to the end plate.

[0035] In some embodiments, in a pre-tightened state, a surface of the positioning plate facing the battery is flush with a surface of the end plate facing the battery.

[0036] In some embodiments, the end of the positioning member that is in contact with the battery is fixedly connected to an elastic abutment member.

[0037] In the above technical solution, by providing an end plate with an initial deflection, when the pre-tightening force is applied to the battery using a fastening bolt, the problem of uneven pre-tightening force applied by the end plate to various areas of the battery can be alleviated, the uniformity of the force applied to the battery can be improved, the electrochemical reaction of the battery can be more uniform, the working efficiency of the battery stack can be improved, and the problem of structural damage can be reduced, thereby extending the service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0039] Figure 1 This is a schematic diagram of a battery stack structure in the related art;

[0040] Figure 2 Schematic diagram of the force applied to the battery in the battery stack structure under pre-tightening state in the related art;

[0041] Figure 3 Schematic diagram of a battery stack structure in an unprestressed state provided in other embodiments of the present application;

[0042] Figure 4 Schematic diagram of a battery stack structure in a pre-tightened state provided in other embodiments of the present application;

[0043] Figure 5 This is a schematic structural diagram of the end plate and the positioning member in some embodiments of the present application;

[0044] Figure 6 for Figure 5 A magnified schematic diagram of part A;

[0045] Figure 7 This is a schematic diagram of the positional relationship of the positioning member relative to the end plate when the end plate is in a pre-tightened state in some embodiments of the present application;

[0046] Figure 8 for Figure 7 An enlarged schematic diagram of part B;

[0047] Figure 9 A schematic diagram of a battery stack structure from another perspective provided in some other embodiments of the present application;

[0048] Figure 10 Schematic diagram of the force on the constructed cantilever beam module;

[0049] Figure 11 Schematic diagram of the relative relationship between the blank and the end plate with initial deflection.

[0050] The reference numerals are as follows:

[0051] 1. End plate, 11. Connecting slot, 12. Giving way slot;

[0052] 2. Battery;

[0053] 3. Tighten the bolts;

[0054] 4. Positioning piece, 41. Connecting plate, 42. Positioning plate;

[0055] 5. Elastic abutment. DETAILED DESCRIPTION

[0056] The present application will be further described in detail below through the accompanying drawings and examples, through which the features and advantages of the present application will become more clear and distinct.

[0057] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by technicians in the technical field to which this application belongs; the terms used in this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification of this application and the above-mentioned drawings and any variations thereof are intended to cover non-exclusive inclusions.

[0058] The phrase "embodiment" mentioned in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it refer to independent or alternative embodiments that are mutually exclusive with other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0059] The term "exemplary" is used herein to mean "serving as an example, embodiment, or illustration." Any embodiment described as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. Although various aspects of the embodiments are shown in the drawings, the drawings are not necessarily drawn to scale unless otherwise indicated.

[0060] In the description of this application, the technical terms "first", "second", "third", etc. are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity, specific order or primary and secondary relationship of the indicated technical features.

[0061] In the description of this application, the technical term "and / or" is simply a description of the association relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the related objects are in an "or" relationship.

[0062] In the description of this application, the orientations or positional relationships indicated by technical terms such as "upper", "lower", "inside", "outside", "front", "back", "left", "right", "top", and "bottom" are orientations or positional relationships based on the working state of this application. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on this application.

[0063] In the description of this application, unless otherwise specified or limited, technical terms such as "mounted," "connected," "connect," and "fixed" should be understood broadly. For example, these terms may refer to fixed connections, removable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediary; and internal connections between two components or interactions between two components. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0064] In the description of this application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, a first feature being "above," "above," and "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is at a higher level than the second feature. A first feature being "below," "below," and "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0065] In the description of the present application, “a plurality of” means two or more (including two), unless otherwise clearly and specifically defined.

[0066] In the description of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, and other dimensions of the integrated device shown in the drawings are merely illustrative and do not constitute any limitation on this application.

[0067] As part of the creative concept of the present application, before describing the embodiments of the present application, it is necessary to analyze the reasons why the end plate applies uneven pre-tightening force to the battery in the related technology, resulting in uneven electrochemical reaction of the battery, and obtain the technical solution of the embodiments of the present application through reasonable analysis.

[0068] In related technologies, fuel cells and electrolyzer stack structures use end plates to clamp multiple cells and apply a preload to the cells. Two end plates are placed at either end of a stack of cells, and the two end plates are preloaded with bolts. Multiple bolts are placed around the end plates, applying a preload toward the cells. This preload inevitably deforms the end plates, meaning the area where the end plates are connected to the bolts shifts in the direction of the force. This acts on the end plates as a whole, causing the edges of the end plates to bend in the direction of the force, i.e., the side where the cells are located, and the middle to arch away from the cells.

[0069] refer to Figure 1 and Figure 2 ,in, Figure 1 shows an existing battery stack structure, Figure 2 The figure shows the distribution of the preload applied by the end plate 1 to the battery 2 in various regions in the existing structure. In the existing structure, the end plate 1 is located at the end of multiple stacked batteries 2, with only one end plate 1 shown in the figure. Under the preload applied by the bolts, the end plate 1 forms a spherical structure with the center arching away from the battery 2. This results in different preloads applied by the end plate 1 to different regions of the battery 2, resulting in uneven force on the battery 2, with the active reaction zone in the center receiving less preload, or even no preload at all.

[0070] Uneven force on battery 2 will cause uneven spatial distribution of resistance, flow resistance, and interface contact pressure, which will cause uneven electrochemical reaction, resulting in reduced efficiency of fuel cells and electrolyzer stacks and shortened service life.

[0071] To this end, the present application provides a battery stack structure to solve the technical problem in the prior art that the pre-tightening force applied by the end plate 1 to the battery 2 is uneven, resulting in uneven electrochemical reaction of the battery 2, reduced efficiency of the fuel cell and electrolyzer, and shortened service life.

[0072] The technical solutions of the embodiments of the present application are described in detail below with reference to the accompanying drawings. The technical features involved in the different implementation modes of the present application described below can be combined with each other as long as there is no conflict between them.

[0073] refer to Figure 3 In an embodiment of the present application, a battery stack structure is provided, including a battery 2, an end plate 1 and a fastening bolt 3. There are multiple batteries 2, and the multiple batteries 2 are stacked with their large surfaces attached to each other; there are two end plates 1, which are respectively arranged at the two ends of the multiple stacked batteries 2. In other embodiments, four, six or other end plates 1 can also be set. The embodiment of the present application takes two as an example for illustration.

[0074] Multiple fastening bolts 3 are connected between the two end plates 1, applying a pre-tightening force to the end plates 1 toward the battery cells 2, thereby clamping the end plates 1 against the battery cells 2. The multiple fastening bolts 3 are divided into two groups, each located on one of the opposite sides of the end plates 1. It should be understood that the fastening bolts 3 located on the side of the end plates 1 refer to the fastening bolts 3 being located near the edge of the end plates 1 and arranged along the edge of the end plates 1.

[0075] The end plate 1 has an initial deflection from the central axis to the two side edges connected to the fastening bolts 3, which is away from the battery 2. That is, from the central axis of the end plate 1 to the two side edges where the fastening bolts 3 are located, the end plate 1 bends in the direction away from the battery 2; wherein, the central axis is parallel to the edge of the end plate 1 where the fastening bolts 3 are located.

[0076] The end plate 1 is provided with an initial deflection in the direction away from the battery 2, so as to offset the deformation of the end plate 1 caused by the pre-tightening force applied by the fastening bolts 3 to the end plate 1, thereby improving the uniformity of the force between the end plate 1 and the battery 2; in this way, the uniformity of the electrochemical reaction of the battery 2 can be improved, and correspondingly, the working efficiency of the fuel cell and the electrolyzer can be improved, and the service life can be extended.

[0077] refer to Figure 3The initial deflection of the end plate 1 gradually increases in the direction from the central axis of the end plate 1 toward the edges on both sides of the end plate 1 where the fastening bolts 3 are connected. Due to the characteristic that the bolts exert a pre-tightening force on the end plate 1, causing deformation of the end plate 1, the closer to the edge where the fastening bolts 3 are connected, the greater the deformation of the end plate 1. Therefore, the closer the end plate 1 is to the position where the fastening bolts 3 are connected, the greater the initial deflection in the direction away from the battery 2. After being deformed by the pre-tightening force exerted by the fastening bolts 3, the final state of the end plate 1 is closer to horizontal. Here, horizontal means that the end plate 1 and the battery 2 remain in close contact.

[0078] refer to Figure 4 , shows the state after a set preload force is applied to the end plate 1 and battery 2 by tightening bolts 3. The surface of the end plate 1 facing the battery 2 is parallel to the surface of the battery 2 facing the end plate 1, that is, the end plate 1 and battery 2 are in close contact. The set preload force refers to the amount of preload force required to be applied to the battery 2, determined during the stack design process. How to determine this value is well known to those skilled in the art and will not be further described here.

[0079] In this case, the end plate 1 and various areas of the battery 2 maintain a flat state, which can ensure that the set preload force applied by the end plate 1 is evenly transmitted to various areas on the battery 2, and the electrochemical reaction in various areas of the battery 2 remains uniform, thereby improving the working efficiency of the battery stack structure and extending its service life.

[0080] Exemplarily, the end plate 1 is rectangular, and the two groups of fastening bolts 3 are respectively arranged along the two long sides of the end plate 1 .

[0081] During the assembly of the battery stack, it is necessary to ensure that the position of the battery 2 relative to the end plate 1 is accurate, so as to avoid the problem of deflection of the pressure applied to the battery 2 during the subsequent pressurization process. In order to achieve the positioning of the battery 2 relative to the end plate 1 more conveniently and accurately, refer to Figure 5 A positioning member 4 for limiting the position of the battery 2 is provided on the end plate 1.

[0082] Specifically, there are at least two positioning members 4, two of which are respectively used to abut two adjacent side surfaces of the battery 2. The side surfaces of the battery 2 abut the positioning members 4, thereby defining the position of the battery 2 relative to the end plate 1. In other embodiments, there may be three, four, or five positioning members 4, etc., and the positioning members 4 may be respectively provided relative to different side surfaces of the battery 2, with multiple positioning members 4 provided corresponding to one or more side surfaces of the battery 2.

[0083] By presetting the position of the battery 2 and using the positioning member 4 to limit the position of the battery 2, during the assembly process, there is no need to use additional measurement or other means to ensure that the position of the battery 2 relative to the end plate 1 meets the set requirements. This improves the convenience of the assembly process, and it is more convenient and accurate to determine the position of the battery 2, which can improve work efficiency. It can also reduce the problem of deviation in the position of the battery 2 relative to the end plate 1 during the assembly process, which leads to a decrease in the quality of the battery 2 and reduced work efficiency, thereby ensuring the quality of the battery stack.

[0084] For example, refer to Figure 5 and Figure 6 The positioning member 4 includes a connecting plate 41 and a positioning plate 42, which are integrally formed. Of course, in other embodiments, the connecting plate 41 and the positioning plate 42 can also be provided as separate structures, which are fixedly connected by welding, bonding, hot melting, etc. In this application, the integral formation of the two is used as an example for explanation.

[0085] The connecting plate 41 is used to connect to the end plate 1. The end plate 1 is provided with a plug-in slot 11 corresponding to the connecting plate 41. The connecting plate 41 is inserted into the plug-in slot 11 and fixed relative to the end plate 1 to achieve the connection between the positioning member 4 and the end plate 1. The fixing of the connecting plate 41 relative to the end plate 1 can be achieved by bonding, or by providing an interference fit between the connecting plate 41 and the plug-in slot 11 to achieve the fixing of the connecting plate 41 relative to the end plate 1, or by using a snap-fit ​​method, as long as the fixing of the connecting plate 41 relative to the end plate 1 is guaranteed.

[0086] In addition, the end plate 1 is provided with a clearance groove 12 adapted to the positioning plate 42. Figure 5 and Figure 6 , when the end plate 1 has an initial deflection, the end of the positioning plate 42 away from the connecting plate 41 protrudes from the surface of the end plate 1 facing the battery 2 in the clearance groove 12; Figure 7 and Figure 8 , in the pre-tightened state, the positioning plate 42 is located in the clearance groove 12;

[0087] The pre-tightened state refers to the state in which the end plate 1 applies a pre-tightening force to the battery 2 under the action of the fastening bolts 3. In this state, the surface of the end plate 1 facing the battery 2 is in contact with the surface of the battery 2 facing the end plate 1. The end plate 1 has an initial deflection, that is, the end plate 1 is naturally bent.

[0088] In this way, in the natural state, the end of the positioning plate 42 is located outside the clearance groove 12 and protrudes from the surface of the end plate 1. At this time, the battery 2 is placed on the end plate 1, and the positioning plate 42 is used to assist in determining the position of the battery 2 relative to the end plate 1; then pressure is applied to the end plate 1 to make the battery stack reach a pre-tightened state, and the end plate 1 is transformed into a "straight" state. During this process, the positioning plate 42 is received in the clearance groove 12.

[0089] During the assembly process, the positioning plate 42 can position the battery 2, and after the assembly is completed, the positioning plate 42 is automatically accommodated in the clearance groove 12, avoiding the problem that the positioning plate 42 always protrudes from the end plate 1 and affects other components or subsequent work of the battery stack.

[0090] Illustratively, in the pre-tightened state, a surface of the positioning plate 42 facing the battery 2 is flush with a surface of the end plate 1 facing the battery 2 .

[0091] In addition, reference Figure 6 , the end of the positioning plate 42 away from the connecting plate 41 is fixedly connected with an elastic abutment 5, illustratively, the elastic abutment 5 is a rubber block. When the pre-tightening force is applied to the battery stack and the end plate 1 is deformed, the problem of excessive abutment between the positioning plate 42 and the battery 2, which may cause damage to the battery 2, is avoided, and a certain protection effect is played on the battery 2. It should also be noted that in the actual production process, the deflection of the end plate 1 is a small value, and the amount of deformation generated is also small. In the corresponding process, the distance that the positioning plate 42 is offset relative to the battery 2 is also small. By setting the elastic abutment 5, the problem of wear between the positioning plate 42 and the battery 2 can be better avoided.

[0092] In addition, the present application also provides a production process for a fuel cell stack structure, which first determines the initial deflection of the end plate 1, then processes the end plate 1 according to the determined initial deflection, and then assembles the fuel cell stack; specifically, the production process includes the following steps.

[0093] 001. Construct a cantilever beam model

[0094] refer to Figure 9 and Figure 10 , the end plate 1 is divided into multiple force-bearing units extending along the first direction, and the multiple force-bearing units are arranged along the second direction; the first direction is the arrangement direction of the two groups of fastening bolts 3, and the second direction is the arrangement direction of the multiple fastening bolts 3 in each group of fastening bolts 3, and the two are perpendicular to each other.

[0095] One of the fastening bolts 3 in each group is located on the central axis of the force-bearing unit in the first direction, that is, the multiple fastening bolts 3 in the two groups of fastening bolts 3 correspond to each other one by one, and each two corresponding fastening bolts 3 are located at both ends of the same force-bearing unit. The two corresponding fastening bolts 3 are arranged along the first direction and are located on the central axis of the force-bearing unit along the first direction.

[0096] Each force-bearing unit is separated by a symmetry plane parallel to the second direction (the symmetry plane is also perpendicular to the first direction) to form two cantilever beam modules; wherein, the cantilever beam model has one end at the symmetry plane as a fixed end and the end away from the symmetry plane as a free end.

[0097] 002. Determine the force of the cantilever beam model

[0098] Under the action of the fastening bolts 3, the end plate 1 applies a pre-tightening force to the battery 2. The force applied by the fastening bolts 3 to the end plate 1 is concentrated at the connection position with the end plate 1, and the force applied by the battery 2 to the end plate 1 is evenly distributed in the contact area between the end plate 1 and the battery 2.

[0099] Therefore, it is determined that the forces acting on the cantilever beam module include the concentrated load P applied by the fixing bolts and the reaction load q applied by the battery 2, wherein the load q is evenly distributed in the area where the cantilever beam module is in contact with the battery 2, which is a uniformly distributed load; the initial deflection of the cantilever beam is determined by the concentrated load P and the uniformly distributed load q.

[0100] 003. Get the dimensional information related to the cantilever beam model

[0101] The dimension 2L1 of the battery 2 in the first direction is obtained, that is, the distance between the farthest end of the uniformly distributed load q on the cantilever beam module and the fixed end of the cantilever beam module is L1.

[0102] Obtain the vertical distance 2L2 in the first direction of the forces respectively applied by the two sets of fastening bolts 3 on the end plate 1 , that is, the distance between the position where the concentrated load P acts on the cantilever beam module and the fixed end is L2 .

[0103] Obtain the distance b between two adjacent fastening bolts 3 in the same group and the thickness h of the end plate 1, and thereby determine that the lengths of two adjacent sides of the rectangular area where the uniformly distributed load q acts on the cantilever beam module are L1 and h respectively;

[0104] The values ​​of the concentrated load P and the uniformly distributed load q are obtained, and the concentrated load P is determined according to the value of the uniformly distributed load q and the relationship of the force balance in the final state of each cantilever beam module.

[0105] 004. Determine the relationship between the deflection of the cantilever beam model and its position

[0106] According to the relationship between the deflection generated by the force on the cantilever beam module, and the state in which the cantilever beam module ultimately remains parallel to the surface of the battery 2 facing the end plate 1 under the action of loads P and q, the measured deflection of the cantilever beam module generated at different positions from the symmetry plane to the connection with the fastening bolt 3 is determined; the initial deflection is the same as the measured deflection in magnitude but opposite in direction.

[0107] refer to Figure 10 , is the constructed cantilever beam module, where A represents the fixed end, B is the position farthest from A where the uniformly distributed load q acts on the cantilever beam module, and C is the free end of the cantilever beam module; it should be understood that the free end of the cantilever beam module here is not the outermost edge of the end plate 1, but the position where the fastening bolt 3 is connected to the end plate 1.

[0108] The metrological deflection at a position perpendicular to the symmetry plane at a distance x is δ, then δ satisfies:

[0109] δ=δ P -δ q , forx≤L1;

[0110] δ=δ P -y B -(x-L1)tanθ B , for L1 <x≤L2;

[0111] Where x is the distance from the fixed end A, δ P is the deflection of the cantilever beam module under the concentrated load P, δ q is the deflection of the cantilever beam module under the action of uniformly distributed load q, y B is the deflection of the cantilever beam module at point B under the uniform load q, θ B is the rotation angle of the cantilever beam module at point B under the action of uniformly distributed load q.

[0112] Specifically, based on the deflection relationship of the cantilever beam under concentrated load and uniformly distributed load, the following relationship can be obtained:

[0113]

[0114] P = qbL1;

[0115] This part can be directly obtained by those skilled in the art through existing technology and will not be described in detail. Among them, E is the Young's modulus of the material used for the end plate 1.

[0116] It can be obtained that the metrological deflection δ satisfies the following relationship:

[0117]

[0118] The initial deflection of the end plate 1 is the same as the measured deflection in magnitude but opposite in direction, thereby the initial deflection at each position of the end plate 1 can be determined.

[0119] It should be noted that in the embodiment of the present application, the free end of the cantilever beam module is the point where the fastening bolts 3 connect to the end plate 1, rather than the outermost edge of the end plate 1. The portion from the fastening bolt 3 connection point to the edge of the end plate 1 does not experience deformation due to applied force during actual use, and therefore this portion will not be described in detail. In actual processing, this portion can be processed into a flat plate structure or a quasi-arc structure according to actual needs, and a smooth transition can be achieved with the portion of the end plate 1 that deforms under the action of the preload force.

[0120] 005. Determination of relevant dimensions of end plate 1

[0121] According to the above relationship, it can be determined that the maximum initial deflection of the end plate 1 is located at point C, that is, the size of δ when the x value is L2, that is,

[0122] In addition, the maximum stress on the surface of the end plate 1 should be less than the yield strength σ of the material of the end plate 1. The end plate 1 deforms under the action of the preload, and the stress generated on the surface of the symmetry plane perpendicular to the first direction is the largest. It can be obtained that:

[0123] σ max =σ Pmax -σ qmax ;

[0124]

[0125] Where y is the distance between the symmetry plane of the end plate 1 and the surface of the end plate 1, and the symmetry plane is parallel to the first direction and the second direction. When the value of y is h / 2, combined with P=qbL1, we have:

[0126] Therefore, the end plate 1 should meet the following requirements: Among them, q, L1 and σ are the values ​​that can be determined in the actual end plate 1. From this, the relationship between b, h and L2 can be determined. When designing the size of the end plate 1, the above relationship is guaranteed to be satisfied. For example, by first determining two of the three values, the value range of the other value can be determined, and the appropriate size value can be determined accordingly.

[0127] 006. End plate 1 processing

[0128] First, process the raw materials to obtain the cuboid blank, refer to Figure 11 The length of the cuboid blank is determined by the size of battery 2, the width is 2L, the thickness is h and δ max where 2L is the sum of 2L2 and the width reserved on the end plate 1 for connecting the fastening bolts 3.

[0129] The bolt holes for the fastening bolts 3 to pass through are machined on the blank, and the diameter of the bolt holes should be slightly larger than the diameter of the fastening bolts 3 ; here, slightly larger means the margin required to allow the end plate 1 to deform.

[0130] The end plate 1 with the initial deflection is obtained by cutting in a manner of electric spark wire cutting or laser cutting, in accordance with the relationship that the initial deflection and the measured deflection δ are equal in magnitude and opposite in direction.

[0131] 007. Stack assembly

[0132] Place one of the end plates 1 at the bottom, with the middle part of the end plate 1 arched upward, and install the fastening bolts 3 on the bottom end plate 1; install the battery 2 on the bottom end plate 1. For example, the battery 2 is composed of a multi-layer structure. When installing the battery 2, the insulating layer, the ear, the sealing rubber, the porous diffusion layer, the sintered titanium, the proton membrane, the sintered titanium, the porous diffusion layer, the sealing rubber, and the bipolar plate are installed in sequence on the bottom end plate 1 and stacked in sequence; place another end plate 1 on the top, with the middle part of the top end plate 1 concave downward, use a hydraulic press or other equipment to apply a set pre-tightening force to the end plate 1, and use the fastening bolts 3 to connect the two end plates 1 at the bottom and top. After the connection is completed, remove the pressure of the hydraulic press to complete the battery stack assembly.

[0133] Using the above-mentioned production process, the processed end plate 1 has an initial deflection in the direction away from the battery 2. The end plate 1 is fixed with the fastening bolts 3. When a set pre-tightening force is applied to the battery 2, the pre-tightening force applied by the end plate 1 to the battery 2 is ensured to be uniform, that is, the electrochemical reaction in each area of ​​the battery 2 is ensured to be uniform. When used in structures such as fuel cells and electrolyzers, it can improve work efficiency and extend the service life of the equipment.

[0134] In another embodiment, a different method is used to determine the relationship between the deflection of the cantilever beam model and the position, which is different from steps 003 and 004 of the above embodiment. Specifically, based on the above steps 001, 002, 005, 006, and 007, the difference is that this embodiment includes the following steps in place of the original steps 003 and 004:

[0135] 01. Obtain the dimension 2L1 of the battery 2 in the first direction, that is, the distance between the farthest end of the uniformly distributed load q on the cantilever beam module and the fixed end of the cantilever beam module is L1.

[0136] Obtain the vertical distance 2L2 in the first direction of the forces respectively applied by the two sets of fastening bolts 3 on the end plate 1 , that is, the distance between the position where the concentrated load P acts on the cantilever beam module and the fixed end is L2 .

[0137] 02. Use mechanical analysis tools such as Ansys, COMSOL Multiphysics, Abaqus, etc. to model and simulate the constructed cantilever beam module, apply the corresponding concentrated load P and uniformly distributed load q, and obtain the primary deflection δ1 at each position of the cantilever beam module; the initial deflection δ 1 It is the same size as the primary deflection δ1 but in the opposite direction.

[0138] 03. For the initial deflection δ 1 The cantilever beam module is modeled and simulated, and the corresponding concentrated load P and uniform load q are applied to obtain the secondary deflection δ2 of each position of the cantilever beam module. If the value of the obtained secondary deflection δ2 is zero, it means that the initial deflection δ 1This is the final determined initial deflection of the end plate 1. However, considering the actual production needs, if Then δ 1 It is the initial deflection of end plate 1.

[0139] 04. If you are not satisfied This shows that with initial deflection δ 1 The end plate 1, when the pre-tightening force is applied to the battery 2 by tightening the bolts 3, cannot meet the requirement of complete fit between the end plate 1 and the battery 2. There is still a large error. It is necessary to adjust the initial deflection δ 1 Continue making adjustments.

[0140] Then the initial deflection δ of end plate 1 is 2 Satisfaction: δ 2 =δ 1 -δ2. Among them, it is limited to δ 1 If the direction of δ2 is positive, then 1 , then δ2 is negative; if the direction of δ2 is the same as δ 1 , then δ2 is positive.

[0141] It should be noted that the δ 1 The direction of δ2 refers to the deflection direction of the end plate 1 under the action of the concentrated load P and the uniformly distributed load q, rather than the deflection direction when the end plate 1 is installed on the stack structure.

[0142] That is, the initial deflection δ 2 and initial deflection δ 1 And the vector sum of the secondary deflection δ2 is the same in magnitude but opposite in direction.

[0143] 05. For the initial deflection δ 2 The cantilever beam module is modeled and simulated, and the corresponding concentrated load P and uniform load q are applied to obtain the secondary deflection δ3 of each position of the cantilever beam module. If it satisfies, the initial deflection of end plate 1 is δ 2 If not satisfied, refer to δ 1 Determine the initial deflection δ with δ2 2 The initial deflection of the end plate 1 is further modified by δ 2 Determine the initial deflection δ of end plate 1 with δ3 3 .

[0144] 06. Repeat the above steps 04 and 05, and use the mechanical analysis tool to analyze the initial deflection δ n-1 Apply concentrated load P and uniform load q to the cantilever beam module; obtain the nth deflection δ at each position of the cantilever beam module n , until it satisfies: δn-1 It is the initial deflection of end plate 1.

[0145] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A battery stack structure, characterized in that: Including batteries and end plates; There are multiple batteries, and the multiple batteries are stacked and arranged; There are at least two end plates, which are respectively arranged at both ends of the plurality of batteries; A plurality of fastening bolts are connected between the end plates, and the fastening bolts are connected to the end plates to clamp the battery; The plurality of fastening bolts are divided into two groups, and the two groups of fastening bolts are respectively located on opposite sides of one group of the end plates; The end plates have an initial deflection from the central axis to the two side edges connected with the fastening bolts in the direction away from the battery.

2. The battery stack structure according to claim 1, characterized in that: The initial deflection gradually increases from the center axis of the end plate toward the two side edges connected by the fastening bolts.

3. The battery stack structure according to claim 2, characterized in that: When the fastening bolt applies a set pre-tightening force to the end plate, the surface of the end plate facing the battery is parallel to the surface of the battery facing the end plate.

4. The battery stack structure according to claim 1, characterized in that: The end plate is rectangular; The two groups of fastening bolts are respectively arranged along the two long sides of the end plate.

5. The fuel cell stack structure according to any one of claims 1 to 4, characterized in that: The initial deflection of the end plate satisfies the following relationship: ,for ; ,for ; The initial deflection of the end plate is equal to δ; in, , ; E is the Young's modulus of the end plate material; L1 is the size of the battery in the first direction ; L2 is the vertical distance in the first direction between the forces applied by the two sets of fastening bolts on the end plate. ; b is the distance between two adjacent fastening bolts in the same group; h is the thickness of the end plate; x is the distance from the symmetry plane of the two sets of fastening bolts; P is the load applied by each of the fastening bolts to the end plate; q is the uniformly distributed load between the battery and the end plate; The first direction is the arrangement direction of the two sets of fastening bolts.

6. The battery stack structure according to claim 1, characterized in that: A positioning piece is provided on the end plate, and the side surface of the battery is in contact with the positioning piece to define the position of the battery relative to the end plate; There are at least two positioning members, two of which are respectively used to abut against two adjacent side surfaces of the battery.

7. The battery stack structure according to claim 6, characterized in that: The positioning member includes a connecting plate and a positioning plate arranged on the connecting plate; The connecting plate is connected to the end plate; A clearance groove is provided on the end plate, and the positioning plate is located in the clearance groove in the pre-tightened state. When the end plate has an initial deflection state, the end of the positioning plate away from the connecting plate protrudes from the clearance groove to the surface of the end plate facing the battery side.

8. The battery stack structure according to claim 7, characterized in that: The end plate is provided with an inserting slot, the connecting plate is inserted into the inserting slot and is fixed relative to the end plate.

9. The battery stack structure according to claim 7, characterized in that: In the pre-tightened state, the surface of the positioning plate facing the battery is flush with the surface of the end plate facing the battery.

10. The battery stack structure according to claim 6, characterized in that: The end of the positioning member that is in contact with the battery is fixedly connected with an elastic abutting member.

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