A battery stack bundling assembly and fuel cell

Abstract

The present invention discloses a battery stack bundling assembly and a fuel cell. The battery stack bundling assembly comprises: a rolled strip, a support plate and a buffer plate. The buffer plate is tightly matched with the stack core. The end interface of the tie is welded to form a fixed ring band to form the fastening force required by the battery stack structure. The operation is simple and the sealing of the battery stack will not be affected by the problem of long use time. By arranging the support plate and the buffer plate between the rolled strip and the stack core, on the one hand, the stack core is protected. On the other hand, the fastening force of the rolled strip is further increased by designing the support plate, thereby also improving the battery stack power density of the fuel cell using the battery stack bundling assembly.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical power sources, and in particular to a battery stack bundling assembly and a fuel cell. Background Art

[0002] A fuel cell is a device that directly converts the chemical energy of a fuel into electrical energy. Fuel cell power generation is not limited by the Carnot cycle. Currently, the energy conversion efficiency of fuel cells is about 40% to 60%, and the power generation efficiency is high. Fuel cells emit almost no nitrogen and sulfur oxides, which reduces air pollution. The emission of carbon dioxide is reduced by more than 40% compared to the heat engine process, which is very important for alleviating the greenhouse effect of the earth. The actual specific energy of fuel cells is much higher than that of ordinary batteries.

[0003] Compared with lithium batteries, fuel cells have obvious advantages: the good thermal energy of hydrogen as a fuel, the reaction efficiency when working, especially its excellent low-temperature starting ability, short-time refueling ability and long endurance after a single refueling, which have become important incentives for it to be valued in the current market.

[0004] In the future, as downstream applications demand increased performance, fuel cells will also develop in the direction of higher operating temperatures, greater efficiency, and lower costs, requiring major innovations in the materials and designs of each component.

[0005] At present, the cost, durability, low temperature performance and power density of fuel cells still need to be improved. As the core component of fuel cells, the stack is the core of external power output, and its cost accounts for about 42% to 62% of the total cost of the fuel cell system. Therefore, the development of the stack is crucial to the promotion and application of fuel cells.

[0006] The design process of the fuel cell stack includes the materials, dimensions, performance indicators, sealing and packaging methods of each component of the fuel cell stack. The plate in the stack is one of the important components. In the current market, graphite bipolar plates have basically been domestically produced. Graphite bipolar plates have good electrical and thermal conductivity and ductility, and low process costs. There are also metal bipolar plates, but the development of high-performance metal plates is difficult. The surface of the metal bipolar plate is more susceptible to corrosion, and a metal passivation film is formed on the surface, which increases the contact resistance. This will reduce the performance of the stack and reduce its service life. Regardless of the above-mentioned bipolar plate, the sealing and packaging method of the stack are important links.

[0007] In the process of designing the battery stack, in order to obtain the desired power generation performance and play the sealing function, the battery stack needs to apply appropriate tightening force. In the prior art, the fastening parts of the battery stack are generally fastened with bolts according to the packaging form. The bolt fastening is composed of screws, nuts and gaskets, and the strap fastening method is composed of steel strips and spring washers. The installation process is cumbersome, which affects the assembly efficiency and has high production costs, such as CN113745623A; at the same time, as the use time increases, the bolts are easy to loosen, affecting the sealing of the battery stack, and then affecting the power density and output power of the battery stack. Summary of the invention

[0008] In order to overcome the defects of the prior art, the present invention has been found through continuous research and development experiments that the interfaces at both ends of the metal cable tie are welded to form a fixed ring belt, and a tightening force is applied to the structure on the battery stack. The operation is simple, and the sealing of the battery stack will not be affected by the problem of long use time, thereby improving the power density and output power of the battery stack. However, while strengthening the sealing of the battery stack, it should not cause external force damage to the core, and the sealing failure problem caused by the misalignment of the single cell under the impact of external force. Therefore, the battery stack bundling assembly was improved after further research. By arranging a support plate and a buffer plate between the rolling strip and the core, on the one hand, the core is protected, and the sealing failure problem caused by the misalignment of the single cell under the impact of external force is solved. On the other hand, the tightening force of the rolling strip is further increased by designing the support plate, thereby improving the power density and output power of the battery stack.

[0009] On the one hand, the present invention proposes a battery stack bundling assembly, comprising: a rolled strip, on which pin holes are provided; a support plate, the support plate comprising: a first side surface and a second side surface, the first side surface of the support plate having a recessed groove for accommodating the rolled strip; and a buffer plate, the buffer plate being adjacent to the second side surface of the support plate.

[0010] One end of the rolled strip is fixed, and the other end surrounds the battery stack body and merges with one end of the rolled strip. The rolled strip is tightened using a pre-tensioning structure to achieve welding of the rolled strip interface.

[0011] The pin hole is used to cooperate with the pre-tensioning structure to achieve the tightening welding of the rolling strip. A pin is provided at one end of the pre-tensioning structure. The pin is inserted into the pin hole to provide the rolling strip tension under the action of external force. The tension is evenly applied to various components of the stack, so that the core is tightened and sealed, and the core and other structures are prevented from loosening during the assembly process of the stack. The pin hole is generally provided near the interface at one end of the rolling strip, so that a more uniform tension can be applied to the entire core.

[0012] The buffer plate can be in a close fit with the support plate and the core. The rolling strip transmits the fastening force to the outside of the core through the end plates at both ends of the core, and transmits the fastening force to the core through the support plate and the buffer plate on both sides of the single cell stack.

[0013] In addition, when an impact occurs, the battery stack binding assembly can prevent the failure of sealing due to the misalignment of single cells. The battery stack of the core is maintained by the fastening load of the battery stack binding assembly, its reaction force, and the friction binding force generated by the friction coefficient between the batteries. When a large impact exceeding the friction binding force is applied, the inertial force generated by the impact in the battery stack causes the battery stack to move dynamically, and the fastening force provided by the buffer plate and the support plate can suppress the displacement of the batteries in the battery stack to a specified value. At the same time, the contact design between the support plate and the rolling strip can be used to suppress the displacement between the batteries below the specified value by utilizing the reaction force during intentional contact.

[0014] Furthermore, in the battery stack bundling assembly of the present invention, the depth of the two ends of the trough is greater than the depth in the middle, and the bottom surface of the trough has a highest point A and a lowest point B, wherein the angle between the AB line and the core stacking direction is α, and 7°≤α≤12°.

[0015] Furthermore, the maximum depth of the sink in the battery stack bundling assembly of the present invention is 1.5 mm to 3 mm.

[0016] The bottom surface of the sink in the battery stack bundling assembly of the present invention may be designed to be arc-shaped.

[0017] Whether it is the graphite bipolar plate with mature technology in the current market or the metal bipolar plate in the technical public relations stage, its thickness is at the level of several millimeters. For example, the thickness of the commercially available engraved graphite bipolar plate is about 1.5 to 2.5 mm. Bipolar plates are extremely susceptible to damage during assembly, packaging, and use. Here, only bipolar plates are used as an example, but the types of plates are not limited. Through the structural design of the support plate sink groove, intentional contact between the support plate and the rolling strip is achieved when the battery stack is impacted, and the reaction force during intentional contact is used to suppress the displacement between the batteries below the specified value.

[0018] Furthermore, the sink in the battery stack bundling assembly of the present invention is provided with a groove corresponding to the pin hole.

[0019] The groove and the pin hole correspond to provide an insertion space for the pre-fastening structure, so as to better apply the pre-fastening force.

[0020] Furthermore, the first side surface of the support plate in the battery stack bundling assembly of the present invention is provided with a strip tunnel perpendicular to the extension direction of the sinking groove, and the depth of the strip tunnel is greater than the depth of the sinking groove.

[0021] The strip-shaped tunnel provides space for using disassembly tools when disassembling the rolled strip, thereby preventing damage to the support plate.

[0022] Furthermore, the rolled strip material in the battery stack bundling assembly of the present invention is a metal material, and the metal material is preferably stainless steel, and the thickness of the stainless steel plate is 0.3mm~2mm; the buffer plate material is an elastic material, and the elastic material can be selected from silicone, EPDM rubber, fluororubber, silicone and polyisobutylene, etc.

[0023] The buffer plate material preferably selects a material whose elastic modulus changes greatly with the input speed, and can be used in a compressed state during assembly. The battery stack has improved impact resistance by supporting bending and suppressing unit dislocation, thereby ensuring impact resistance in the event of a collision.

[0024] Furthermore, the support plate in the battery stack bundling assembly of the present invention is an integral injection-molded structure.

[0025] On the other hand, the present invention also provides a fuel cell, comprising: a stack body and the stack bundling assembly described above; the stack body comprises a first end plate, a second end plate and a core; the core is composed of a plurality of stacked single cell assemblies, with current collecting plates provided at both ends, located between the first end plate and the second end plate; the cable tie is wound around the stack body.

[0026] Furthermore, in the fuel cell of the present invention, the lengths of the support plate and the buffer plate are both less than the core height, the length of the buffer plate is greater than or equal to the length of the support plate, and the width of the buffer plate is greater than or equal to the width of the support plate.

[0027] The support plate cooperates with the core in the fuel cell stack and is located between the two end plates of the fuel cell stack. On the one hand, it is used to provide support for the rolling strip and limit the lateral displacement of the rolling strip; on the other hand, it protects the core from damage caused by the collision of the rolling strip. If the length of the support plate is greater than the height of the core in the stacking direction, the core will not get the appropriate fastening force and will become loose and unable to be sealed. During the stacking process of the single cells of the core under the action of gravity, there are tiny gaps between the single cell layers. Under the action of the external fastening force, such gaps will be eliminated and sealing will be achieved, and then the stacking height of the core will decrease. If the length of the support plate is equal to the height of the core in the stacking direction, the core will not get the appropriate fastening force and will become loose and unable to be sealed. The design of the length of the buffer plate also has the same situation as above.

[0028] Furthermore, in the fuel cell of the present invention, both side surfaces of the first end plate and the second end plate are respectively provided with slots that cooperate with the support plate.

[0029] The slots of the first and second end plates are used to limit the left-right displacement of the support plate. The slot structure can replace the concave design on the end plates for accommodating the rolled strip.

[0030] Furthermore, the fuel cell of the present invention comprises at least two sets of the battery stack binding assemblies. The battery stack binding assemblies in the fuel cell are designed mainly to ensure the sealing of the battery stack, so at least two sets of the battery stack binding assemblies can achieve the desired effect.

[0031] The advantages of the present invention are as follows:

[0032] The present invention welds the metal tie interface to form a fixed ring belt, applies a fastening force to the battery stack body structure, is easy to operate, and does not affect the sealing of the battery stack due to long-term use, thereby improving the power density and output power of the battery stack.

[0033] The present invention provides a support plate and a buffer plate between the rolling strip and the core, which can protect the core on the one hand and further increase the fastening force of the rolling strip by designing the structure of the support plate on the other hand. It also solves the sealing failure problem caused by the misalignment of single cells under external impact, thereby improving the power density and output power of the stack. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Schematic diagram of the overall structure of the battery stack bundle assembly

[0035] Figure 2 Schematic diagram of explosion of battery stack bundled components

[0036] Figure 3 Schematic diagram of pre-tensioning structure for strip welding

[0037] Figure 4 Overall schematic diagram of the support plate structure

[0038] Figure 5 Schematic diagram of the cross section of the support plate along the DD' plane

[0039] Figure 6 Schematic diagram of top view of battery stack bundle assembly

[0040] Figure 7 Schematic diagram of the overall structure of a fuel cell

[0041] The figure numbers are as follows: 100-fuel cell stack bundling assembly, 110-buffer plate, 130-rolled strip, 131-pin hole, 120-support plate, 122-sink, 110-buffer plate, 132-rolled strip interface, 124-strip tunnel, 500-pre-tightening structure, 200-core, 400-first end plate, 300-second end plate, 600-fuel cell stack body. DETAILED DESCRIPTION

[0042] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific implementation methods of the present invention are now described in detail with reference to the accompanying drawings. The described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. If the specific conditions are not specified in the specific implementation methods, they shall be carried out according to the conventional conditions or the conditions recommended by the manufacturer.

[0043] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0044] The terminology used in the present disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure.

[0045] like Figures 1 to 7 As shown, a battery stack binding assembly 100 according to an embodiment of the present invention includes: a rolling strip 130, on which a pin hole 131 is provided; a support plate 120, the support plate 120 includes: a first side surface and a second side surface, the first side surface of the support plate 120 has a sink 122 for accommodating the rolling strip;

[0046] A buffer plate is adjacent to the second side surface of the support plate 120 .

[0047] The pin hole 131 cooperates 500 with the pre-tightening structure of the rolling strip 130 during the welding process to complete the welding and sealing of the interfaces 132 at both ends of the rolling strip 130 .

[0048] One end of the rolling strip 130 is fixed, and the other end surrounds the stack body 600 and merges with one end of the rolling strip 130 . The pre-tightening structure 500 is used to tighten the rolling strip to achieve welding of the rolling strip interface 132 .

[0049] The pin hole 131 is used to cooperate with the pre-tensioning structure to achieve the fastening welding of the rolling strip 130. A pin is provided at one end of the pre-tensioning structure 500. The pin is inserted into the pin hole 131 to provide the rolling strip tension under the action of external force. The tension is evenly applied to various components of the stack, so that the core 200 is fastened and sealed, and the core and other structures are prevented from loosening during the assembly process of the stack. The pin hole 131 is generally set near the interface at one end of the rolling strip 130, so that a more uniform tension can be applied to the entire core.

[0050] In one embodiment of the present invention, the buffer plate 110 is generally in close cooperation with the support plate 120 and the core 200. The rolling strip 130 transmits the fastening force to the outside of the core 200 through the end plates at both ends of the core 200, and transmits the fastening force to the core 200 through the support plate 120 and the buffer plate 110 on both sides of the single cell stack.

[0051] In addition, when an impact occurs, the battery stack binding assembly 100 can prevent the failure of sealing due to the misalignment of the single battery. Through the contact design between the support plate 120 and the rolling belt 130, the displacement between the batteries is suppressed below the specified value by utilizing the reaction force during intentional contact.

[0052] Reference Figure 4 and Figure 5 In one embodiment of the present invention, the depth of the two ends of the sink 122 in the battery stack binding assembly is greater than the depth in the middle, and the bottom surface of the sink 122 has a highest point A and a lowest point B, wherein the angle between the AB line and the core stacking direction is α, and 7°≤α≤12°. The maximum depth of the sink 122 is 1.5mm~3mm. The bottom surface of the sink 122 can be designed to be arc-shaped.

[0053] Through the structural design of the support plate groove 122, intentional contact is achieved between the support plate 120 and the rolling strip 130 when the battery stack is impacted, and the reaction force during the intentional contact is used to suppress the displacement between the batteries below a specified value.

[0054] In one embodiment of the present invention, a groove 123 corresponding to the pin hole 131 is provided on the sink 122 of the battery stack binding assembly 100 .

[0055] The groove 123 and the pin hole 131 correspond to provide an insertion space for the pre-tightening structure, so as to better apply the pre-tightening force.

[0056] In one embodiment of the present invention, a strip tunnel 124 perpendicular to the extension direction of the sink 122 is disposed on the first side of the support plate 120 in the stack binding assembly 100 , and the depth of the strip tunnel 124 is greater than the depth of the sink 122 .

[0057] The strip tunnel 124 provides space for using disassembly tools when the rolling strip 130 is disassembled, thereby preventing damage to the support plate 120 .

[0058] In one embodiment of the present invention, the material of the rolled strip 130 in the stack bundling assembly 100 is stainless steel, and the thickness of the rolled strip 130 is 0.3 mm to 2 mm; the material of the buffer plate is silicone, EPDM rubber, fluororubber or polyisobutylene.

[0059] The material of the buffer plate 110 is preferably selected from a material whose elastic modulus varies greatly with the input speed, and can be used in a compressed state during assembly. The battery stack has improved impact resistance by supporting bending and suppressing unit dislocation, thereby ensuring impact resistance in the event of a collision.

[0060] In one embodiment of the present invention, the support plate 120 in the battery stack binding assembly 100 is an integral injection-molded structure.

[0061] Reference Figure 6 and Figure 7 According to another embodiment of the present invention, a fuel cell comprises: a stack body 600 and the above-mentioned stack bundling assembly 100; the stack body 600 comprises a first end plate 400, a second end plate 300 and a core 200; the core 200 is composed of a plurality of stacked single cell assemblies, with current collecting plates provided at both ends, located between the first end plate 400 and the second end plate 300; the rolling strip 130 is wound on the stack body 600.

[0062] In a fuel cell of another embodiment of the present invention, the lengths of the support plate 120 and the buffer plate 110 are both less than the core height, the length of the buffer plate 110 is greater than or equal to the length of the support plate 120 , and the width of the buffer plate 110 is greater than or equal to the width of the support plate 120 .

[0063] The support plate 120 cooperates with the core in the stack and is located between the two end plates of the stack. On the one hand, it is used to provide support for the rolling strip 130 and limit the lateral displacement of the rolling strip; on the other hand, it protects the core 200 from damage caused by the collision of the rolling strip 130. If the length of the support plate 120 is greater than the height of the core 200 in the stacking direction, the core 200 will not get the appropriate fastening force and will become loose and unable to be sealed. During the stacking process of the single cells of the core 200 under the action of gravity, there are tiny gaps between the single cell layers. Under the action of the external fastening force, such gaps will be eliminated to achieve sealing, and then the stacking height of the core will decrease; if the length of the support plate is equal to the height of the core in the stacking direction, the core 200 will not get the appropriate fastening force and will become loose and unable to be sealed. The design of the length of the buffer plate 110 also has the same situation as above.

[0064] In another embodiment of the present invention, the first end plate 400 and the second end plate 300 in the fuel cell are provided with slots on both sides thereof that match the support plate 120. The slots of the first end plate 400 and the second end plate 300 are used to limit the left and right displacement of the support plate 120. This slot structure can replace the concave design on the end plate for accommodating the rolling strip.

[0065] In another embodiment of the present invention, the fuel cell comprises at least two sets of battery stack binding assemblies 100. The battery stack binding assemblies 100 in the fuel cell are mainly designed to ensure the sealing of the battery stack, so at least two sets of battery stack binding assemblies 100 are required to achieve the desired effect.

[0066] The above-mentioned embodiment of the present invention welds the metal tie interface to form a fixed ring belt, applies a tightening force to the battery stack body structure, is easy to operate, and will not affect the sealing of the battery stack due to the problem of long-term use, thereby improving the power density and output power of the battery stack. At the same time, by arranging a support plate and a buffer plate between the rolling belt and the core, on the one hand, the core is protected, and on the other hand, the tightening force of the rolling belt is further increased by designing the structure of the support plate. It also solves the problem of sealing failure caused by the misalignment of single cells under external force impact, thereby improving the power density and output power of the battery stack.

[0067] The above description is only a preferred embodiment of the present disclosure and is not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure shall be included in the scope of protection of the present disclosure. In addition, various modifications may be made to the present invention for specific circumstances or specific situations without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed, but should include all implementation methods that fall within the scope of the claims of the present invention.

[0068] It should be understood that the present disclosure is not limited to the exact structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims

1. A battery stack bundling assembly, characterized in that: include: A rolled strip, wherein the rolled strip is provided with pin holes; A support plate, the support plate comprising: a first side surface and a second side surface, the first side surface of the support plate having a sink groove for accommodating the rolled strip; a buffer plate, the buffer plate being adjacent to the second side surface of the support plate; Also included is a core composed of a plurality of stacked single cell assemblies; The depth of the two ends of the trough is greater than the depth of the middle part, and the bottom surface of the trough has a highest point A and a lowest point B, wherein the angle between the AB line and the stacking direction of the single cell assembly in the core is α, and 7°≤α≤12°.

2. The battery stack bundling assembly according to claim 1, characterized in that: The maximum depth of the sink is 1.5 mm to 3 mm.

3. The battery stack bundling assembly according to claim 2, characterized in that: The sink is provided with a groove corresponding to the pin hole.

4. The battery stack bundling assembly according to claim 3, characterized in that: A strip-shaped tunnel perpendicular to the length direction of the sinking trough is disposed on the first side surface of the support plate, and the depth of the strip-shaped tunnel is greater than the depth of the sinking trough.

5. The battery stack bundling assembly according to claim 4, characterized in that: The rolling strip material is a metal material, the buffer plate material is an elastic material, and the support plate is an integral injection molding structure.

6. A fuel cell, characterized in that: include: A battery stack body and a battery stack bundling assembly as described in any one of claims 1 to 5; the battery stack body comprises a first end plate, a second end plate and a core; the core is composed of a plurality of stacked single cell assemblies, current collecting plates are provided at both ends of the core, and the core is located between the first end plate and the second end plate; the rolled strip is wound on the battery stack body.

7. The fuel cell according to claim 6, characterized in that The lengths of the support plate and the buffer plate are both smaller than the core height, the length of the buffer plate is greater than or equal to the length of the support plate, and the width of the buffer plate is greater than or equal to the width of the support plate.

8. The fuel cell according to claim 6, characterized in that Both side surfaces of the first end plate and the second end plate are respectively provided with slots matched with the support plate.

9. The fuel cell according to claim 8, characterized in that The fuel cell comprises at least two sets of the fuel cell stack bundling assemblies.

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