A stack end plate embedded with a current collecting plate, a stack and a fuel cell

Abstract

The present invention discloses a stack end plate, a stack, and a fuel cell having an embedded current collecting plate. The stack end plate having an embedded current collecting plate is an integrally injection-molded insulating end plate. The stack end plate comprises an end plate body and a current collecting plate. The end plate body comprises a first plate surface and a second plate surface, the current collecting plate being adjacent to the first plate surface. The first plate surface is provided with a current collecting plate embedding groove, the current collecting plate being embedded in the current collecting plate embedding groove, and a groove is provided along the inner edge of the current collecting plate embedding groove. The present invention solves the problem of bipolar plate damage caused by the flatness and dimensional tolerance of the injection molded surface, ensures the sealing of the stack, and not only solves the safety hazards caused by gas leakage, but also improves the power density of the stack. Furthermore, the product qualification rate and production efficiency of the stack are improved, and the production cost of the stack is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical power sources, and in particular to a stack end plate embedded with a current collecting plate, a stack and a fuel cell. Background Art

[0002] Fuel cells offer significant advantages over lithium-ion batteries, including superior low-temperature start-up capability, short refueling times, and long driving range after a single refueling, attracting significant market attention. However, fuel cell cost, durability, low-temperature performance, and power density remain in urgent need of improvement, hindering industrialization. The fuel cell stack, the core component of a fuel cell and the source of external power output, accounts for approximately 42% to 62% of the total fuel cell system cost, making its development crucial for the widespread application of fuel cells. my country's fuel cell technology development roadmap calls for increasing the stack power density from 2.5kW / L to 4-4.5kW / L and increasing the localization rate of key components from 50% to 90-98%. Stack end plates and insulation plates are key components in the development and design of fuel cells, and their material selection and structural design are key factors influencing stack performance, lifespan, and cost.

[0003] In existing technology, a fuel cell stack consists of end plates, insulating plates, seals, bipolar plates, gas diffusion layers, MEAs, and fasteners. The bipolar plates, gas diffusion layers, and MEAs constitute the stack core. Stacks place high demands on the sealing performance of their packaging. Poor stack sealing can easily lead to gas leakage, posing a safety hazard and impacting stack power density. To ensure sealing, the stack assembly or packaging process requires packaging forces or component fastening forces.

[0004] The insulating plate on the battery stack needs to be embedded in the current collecting plate. Since the insulating plate is an injection-molded part, its flatness and dimensional tolerance are difficult to control. This will form an upward convex step at the joint between the current collecting plate and the insulating plate. The current collecting plate is a metal part that contacts the bipolar plates of the battery cells. The external force during the assembly or packaging process of the battery stack will cause the bipolar plates to break. Currently, the bipolar plates that can be mass-produced on the market are graphite bipolar plates. Graphite bipolar plates are relatively brittle, and their toughness and hardness are far inferior to those of metal current collecting plates. The upward convex step formed above is also subject to external packaging forces or component tightening forces. If the step height is too large, the graphite will be damaged or even directly cracked, causing damage to the bipolar plate, affecting the power density of the battery stack, and thus affecting the product qualification rate and production cost of the battery stack. To address this problem, existing technologies have eliminated the need for grooves and instead fabricated the entire current collector plate into a uniform shape, directly attaching it to one side of the insulating plate. However, this approach places increased demands on the current collector plate, requiring the design of air inlet and outlet holes and other perforations. This also introduces a significant problem: sealing the current collector plate. This significantly increases production costs and process flow, while reducing efficiency. Summary of the Invention

[0005] In response to the above-mentioned industry challenges in the existing technology, R&D personnel have continuously improved designs and conducted experiments, and found that designing a groove on one side of the insulating end plate that is compatible with the thickness of the current collector is the most economical solution. However, this also requires solving the serious problems caused by the flatness and dimensional tolerance of the injection molded part surface. R&D personnel worked together to design a groove on the inner edge of the current collector embedded in the groove to alleviate or eliminate the step height of the current collector protrusion caused by the flatness and dimensional tolerance of the injection molded part surface. This ensures the sealing of the fuel cell stack, not only solves the safety hazards caused by gas leakage, but also increases the power density of the fuel cell stack. In addition, it improves the product qualification rate and production efficiency of the fuel cell stack, and reduces the production cost of the fuel cell stack.

[0006] Therefore, on one hand, the present invention proposes a fuel cell stack end plate embedded with a current collecting plate, wherein the fuel cell stack end plate is an insulating end plate, and the fuel cell stack end plate includes: an end plate body and a current collecting plate, the end plate body includes a first plate surface and a second plate surface, the current collecting plate is adjacent to the first plate surface; the first plate surface is provided with a current collecting plate embedding groove; the current collecting plate is embedded in the current collecting plate embedding groove; it is characterized in that a groove is provided along the inner edge of the current collecting plate embedding groove.

[0007] The insulating end plate of the present invention is integrally injection-molded, and serves as both an insulating plate and an end plate package. In practice, the functions of the end plate and insulating plate in the prior art are combined into one insulating end plate.

[0008] The grooves described in this invention are intended to mitigate or eliminate the raised step height of the collector plate caused by surface flatness and dimensional tolerances in the plastic part. In this invention, "raised step" and "raise" have the same meaning, and "raise" is primarily used in this disclosure. The cross-sectional shape of the grooves is not limited and can be regular or irregular. The groove sides can be vertical or inclined, and the cross-sectional shape of the grooves can be rectangular, trapezoidal, or other shapes.

[0009] Furthermore, through repeated DOA experiments, researchers discovered that when the protrusions exceed 0.3mm in height, they can cause cracking at the edges of the graphite bipolar plates. However, by designing the groove dimensions and other characteristics, these protrusions can be completely eliminated.

[0010] Furthermore, in the stack end plate with embedded current collecting plates described in the present invention, after the current collecting plates are embedded in the current collecting plate embedding grooves, protrusions are formed on the edges of the current collecting plates, the protrusions are embedded in the grooves, and the height of the protrusions is less than 0.30 mm.

[0011] Furthermore, the height of the protrusion in the stack end plate embedded with the current collecting plate described in the present invention is ≦0.00 mm.

[0012] Furthermore, in the stack end plate embedded with the current collecting plate described in the present invention, the distance from the bottom surface of the groove to the bottom surface of the groove in which the current collecting plate is embedded is the depth of the groove, the depth of the groove is H, and the width of the groove is W; wherein H=0.1mm~0.3mm, W=0.1mm~1mm.

[0013] According to the thickness of the existing current collecting plate, the depth of the current collecting plate embedded in the groove matches the thickness of the current collecting plate, and there is a small range of error between the two. The main function of the current collecting plate is to collect the current generated by the core and output it. However, from this perspective, the larger the contact surface between the current collecting plate and the core, the better. Therefore, the design of the groove should be as small as possible, but it must be ensured that it can accommodate the protrusions described above. This puts higher requirements on the design of the groove accommodation space. Based on a comprehensive study of various reasons, the present invention achieves the design purpose by setting the depth H of the groove and the width W of the groove.

[0014] Furthermore, the depth H and the width W of the groove in the stack end plate embedded with the current collecting plate of the present invention satisfy the relationship: W=(36.67*H-19.17)*H+2.55.

[0015] Furthermore, the stack end plate embedded with the current collecting plate described in the present invention is an air intake end plate.

[0016] Furthermore, in the stack end plate embedded with the current collecting plate described in the present invention, the first channel, the second channel, and the third channel are respectively provided on both sides of the current collecting plate embedding groove, which pass through the first plate surface and the second plate surface; the second plate surface is provided with a mounting hole.

[0017] The stack end plate in which the current collecting plate is embedded in the fuel cell stack structure is an insulating end plate, which is located at two ends of the battery core respectively. The design structure of the stack end plate in the present invention can be used on any insulating end plate of the stack structure for embedding the current collecting plate.

[0018] Furthermore, the stack end plate embedded with the current collecting plate described in the present invention is a blind end plate, and a mounting hole is provided on the plate surface of the second plate surface.

[0019] On the other hand, the present invention also proposes a fuel cell stack, which includes: a core, a fastener, the above-mentioned air intake end plate, and the above-mentioned blind end plate; the core is located between the first plate surface of the air intake end plate and the first plate surface of the blind end plate, and the fastener is detachably connected to the air intake end plate and the blind end plate respectively.

[0020] On the other hand, the present invention further proposes a fuel cell, comprising a housing and the above-mentioned fuel cell stack, wherein the fuel cell stack is arranged in the housing.

[0021] The advantages of the present invention are as follows:

[0022] The present invention provides a stack end plate embedded with a current collector. By designing a groove structure on the inner edge of the current collector embedding slot, this structure alleviates or eliminates the step height of the current collector protrusion caused by the flatness and dimensional tolerance of the injection molded part surface, thereby resolving the problem of bipolar plate damage caused by the flatness and dimensional tolerance of the injection molded part surface. This ensures the sealing of the stack, not only resolving the safety hazards caused by gas leakage, but also increasing the stack power density. Furthermore, it improves the product qualification rate and production efficiency of the stack, and reduces the production cost of the stack. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the installation structure of the air intake end plate and the collecting plate of the present invention;

[0024] Figure 2 This is a schematic diagram of the first plate surface structure of the air intake end plate of the present invention;

[0025] Figure 3 This is a schematic diagram of the second plate surface structure of the air intake end plate of the present invention;

[0026] Figure 4 1 is a schematic cross-sectional view of the air intake end plate of the present invention along the AA' plane;

[0027] Figure 5Schematic diagram of the battery stack structure of the present invention;

[0028] The figures are marked as follows: 100-end plate body, 600-current collecting plate, 103-first plate surface, 104-second plate surface, 101-current collecting plate embedded groove, 102-groove, 201-first channel, 202-second channel, 203-third channel, 131-mounting hole, 300-inlet end plate, 500-core, 400-blind end plate. DETAILED DESCRIPTION

[0029] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0030] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0031] Those skilled in the art will understand that, as mentioned in the background art, in the prior art, the battery stack has very high requirements for the sealing of the package. The battery stack has poor sealing performance, which can easily cause gas leakage. On the one hand, it will be a safety hazard, and on the other hand, it will affect the power density of the battery stack. In order to ensure the sealing, the battery stack assembly or packaging process needs to be subjected to the action of packaging force or component tightening force. The insulating end plate on the battery stack needs to be embedded in the current collecting plate. Since the insulating end plate is an injection molded part, its flatness and dimensional tolerance are difficult to control. This will form an upward convex step at the joint between the current collecting plate and the insulating end plate. The current collecting plate is a metal part. The current collecting plate is in contact with the bipolar plate of the battery cell. The external force during the battery stack assembly or packaging process will cause the bipolar plate to be damaged. Currently, the only bipolar plates that can be mass-produced on the market are graphite bipolar plates. Graphite bipolar plates are relatively brittle, and their toughness and hardness are far inferior to those of metal current collector plates. The upwardly convex step formed above is also subject to external packaging forces or component tightening forces. If the step height is too large, it will damage the graphite or even directly crack it, causing damage to the bipolar plate, affecting the power density of the battery stack, and thus affecting the product qualification rate and production cost of the battery stack. To solve this problem, the existing technology does not adopt a groove design. Instead, the entire current collector is prepared as a plate with a shape consistent with the insulating end plate and directly attached to one side of the insulating end plate. However, this increases the requirements for current collector plate preparation and requires the design of inlet and outlet holes and other channels on the current collector. At the same time, a major problem is introduced: the sealing problem of the current collector; this greatly increases production costs and process flow, and reduces production efficiency.

[0032] In view of this, the technical solution of the embodiment of the present application provides a fuel cell stack end plate embedded with a current collecting plate, and a fuel cell stack and a fuel cell including the end plate.

[0033] See also Figures 1 to 5 As shown, in some embodiments of the present invention, a stack end plate with an embedded current collecting plate is provided, which can be used in a fuel cell. The stack end plate with an embedded current collecting plate is an insulating end plate and includes: an end plate body 100 and a current collecting plate 600. The end plate body 100 includes a first plate surface 103 and a second plate surface 104, with the current collecting plate 600 adjacent to the first plate surface 103; the first plate surface is provided with a current collecting plate embedding groove 101; the current collecting plate 600 is embedded in the current collecting plate embedding groove 101; and the current collecting plate 600 is characterized in that a groove 102 is provided along the inner edge of the current collecting plate embedding groove 101.

[0034] In the present invention, the insulating end plate is integrally injection-molded.

[0035] like Figure 1 As shown, in the present invention, the current collecting plate 600 is embedded in the current collecting plate embedding groove 101 .

[0036] In the present invention, groove 102 is used to mitigate or eliminate the raised step height of the collector plate caused by surface flatness and dimensional tolerances of the plastic part. "Raised step" and "raised" have the same meaning, and "raised" is primarily used in this disclosure. The cross-sectional shape of groove 102 is not limited.

[0037] In some embodiments, the groove 102 may be of a regular shape or an irregular shape.

[0038] In some embodiments, the side surface of the groove 102 can be vertical or inclined, and the cross-sectional shape of the groove can be rectangular, trapezoidal, etc.

[0039] In some embodiments of the present invention, after the current collecting plate 600 in the stack end plate 100 is embedded in the current collecting plate embedding groove 101, a protrusion is formed on the edge of the current collecting plate 600, and the protrusion is embedded in the groove 102, and the height of the protrusion is less than 0.30 mm.

[0040] Furthermore, the height of the protrusion in the stack end plate 100 embedded with the current collecting plate is ≦0.00 mm.

[0041] In this invention, researchers discovered through repeated DOA experiments that when the protrusion height exceeds 0.3mm, it will cause the edge of the graphite bipolar plate to crack. At the same time, by designing the groove size and other characteristics, the protrusion can be completely eliminated.

[0042] In some embodiments, as Figure 4As shown, the distance from the bottom surface of the groove 102 in the stack end plate embedded with the current collecting plate to the bottom surface of the current collecting plate embedded groove 101 is the depth of the groove 102, the depth of the groove 102 is H, and the width of the groove 102 is W; where H = 0.1mm~0.3mm, W = 0.1mm~1mm.

[0043] In some embodiments, the depth H of the groove 102 is 0.15 mm to 0.2 mm, and the width W of the groove 102 is 0.1 mm to 0.5 mm.

[0044] In some embodiments, the depth H of the groove 102 is 0.25 mm to 0.3 mm, and the width W of the groove 102 is 0.55 mm to 1 mm.

[0045] In some embodiments, the depth H of the groove 102 in the stack end plate embedded with the current collecting plate and the width W of the groove 102 satisfy the relationship: W=(36.67*H-19.17)*H+2.55.

[0046] In some embodiments, W=0.1 when H=0.3, or W=0.5 when H=0.15, or W=1 when H=0.1.

[0047] In the present invention, the stack end plate embedded with the current collecting plate may be an air intake end plate of the fuel cell stack or a blind end plate of the fuel cell stack.

[0048] See also Figure 2 As shown, in some embodiments of the present invention, the stack end plate embedded with the collecting plate is an intake end plate, including the end plate body 100 and the collecting plate 600 described in the above embodiments, the end plate body 100 includes a first plate surface 103 and a second plate surface 104, and the collecting plate 600 is adjacent to the first plate surface 103; the first plate surface is provided with a collecting plate embedding groove 101; the collecting plate 600 is embedded in the collecting plate embedding groove 101; it is characterized in that a groove 102 is provided along the inner edge of the collecting plate embedding groove 101; at the same time, the first channel 201, the second channel 202, and the third channel 203 that pass through the first plate surface 103 and the second plate surface 104 are respectively provided on both sides of the collecting plate embedding groove 101; a mounting hole 131 is provided on the plate surface of the second plate surface 104, and the mounting hole 131 is used to connect the stack and the fuel cell casing.

[0049] According to the above embodiment, the shapes of the first channel 201, the second channel 202, and the third channel 203 are not limited and can be regular or irregular. The sizes of the first channel 201, the second channel 202, and the third channel 203 are also not limited and can be designed according to the size of the fuel cell stack. The function of the channels is determined by the design requirements of the fuel cell stack.

[0050] In other embodiments of the present invention, the stack end plate embedded with the current collecting plate is a blind end plate, and a mounting hole is provided on the plate surface of the second plate surface.

[0051] According to the above embodiment, connection holes for installing screws can be provided on the air inlet end plate and the blind end plate, and limiting tunnels for binding with steel belts can also be provided.

[0052] Please refer to Figure 5 As shown, in other embodiments of the present invention, a fuel cell stack is provided, which includes: a core 500, fasteners, the air intake end plate 300 in the above embodiment, and the blind end plate 400 in the above embodiment; the core 500 is located between the first plate surface of the air intake end plate 300 and the first plate surface of the blind end plate 400, and the fasteners are detachably connected to the air intake end plate 300 and the blind end plate 400, respectively.

[0053] The present invention does not limit the structure and type of fasteners. In some embodiments, the fasteners are screw assemblies, and the stack is fastened with screws. In other embodiments, the fasteners are steel belt assemblies, and the stack is fastened with steel belts.

[0054] In other embodiments of the present invention, a fuel cell is provided, comprising a housing and the above-mentioned fuel cell stack, wherein the fuel cell stack is disposed within the housing.

[0055] The above-described embodiments of the present invention address the issue of bipolar plate damage caused by surface flatness and dimensional tolerances of injection-molded parts, ensuring the sealing of the fuel cell stack. This not only eliminates the safety hazard of gas leakage but also increases the stack power density. Furthermore, it improves the product qualification rate and production efficiency of the fuel cell stack, reducing its production cost.

[0056] In the description of the present invention, it should be understood that the terms "length", "width", "thickness", "height", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention 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 should not be understood as limiting the present invention.

[0057] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the quantity of the technical features indicated. Thus, features defined as "first" or "second" may explicitly or implicitly include at least one of these features.

[0058] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral molding. Unless otherwise specified or limited, those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0059] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples" or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0060] The present invention is described by the above-mentioned specific embodiments. It should be understood by those skilled in the art that various changes and equivalent substitutions may be made to the present invention without departing from the scope of the present invention. Parts not described in detail in the present specification are well-known technologies to those skilled in the art. In addition, various modifications may be made to the present invention for specific situations or specific circumstances without departing from the scope of this new use. Therefore, the present invention is not limited to the specific embodiments disclosed, but should include all embodiments falling within the scope of the claims of the present invention.

Claims

1. A stack end plate embedded with a current collecting plate, characterized in that: The stack end plate is an insulating end plate, comprising an end plate body and a current collecting plate. The end plate body comprises a first plate surface and a second plate surface, and the current collecting plate is adjacent to the first plate surface. The first plate surface is provided with a current collecting plate embedding groove. The current collecting plate is embedded in the current collecting plate embedding groove. A groove is provided along the inner edge of the current collecting plate embedding groove. After the current collecting plate is embedded in the current collecting plate embedding groove, a protrusion is formed on the edge of the current collecting plate, and the protrusion is embedded in the groove, and the height of the protrusion is less than 0.30 mm; The distance from the bottom surface of the groove to the bottom surface of the current collecting plate embedded in the groove is the depth of the groove, the depth of the groove is H, and the width of the groove is W; Among them, H = 0.1mm ~ 0.3mm, W = 0.1mm ~ 1mm; The depth H of the groove and the width W of the groove satisfy the relationship: W=(36.67*H-19.17)*H+2.

55.

2. The stack end plate embedded with a current collecting plate according to claim 1, characterized in that: The height of the protrusion is ≦0.00 mm.

3. The stack end plate embedded with a current collecting plate according to claim 1 or 2, characterized in that: The stack end plate is an air intake end plate.

4. The stack end plate embedded with a current collecting plate according to claim 3, characterized in that: A first channel, a second channel, and a third channel are respectively provided on both sides of the current collecting plate embedding groove, which pass through the first plate surface and the second plate surface; and a mounting hole is provided on the plate surface of the second plate surface.

5. The stack end plate embedded with a current collecting plate according to claim 1 or 2, characterized in that: The stack end plate is a blind end plate, and a mounting hole is provided on the plate surface of the second plate surface.

6. A fuel cell stack, characterized in that: The fuel cell stack includes: a core, fasteners, an air intake end plate as described in any one of claims 3-4, and a blind end plate as described in claim 5; the core is located between the first plate surface of the air intake end plate and the first plate surface of the blind end plate, and the fasteners are detachably connected to the air intake end plate and the blind end plate respectively.

7. A fuel cell comprising a housing and the fuel cell stack according to claim 6, wherein the fuel cell stack is arranged in the housing.

Images