High-power stack for vanadium cell

Abstract

The application discloses a high-power stack for a vanadium battery, which comprises a current collector, end electrode frames and single cells stacked in sequence, wherein the single cell comprises an electrode frame, a bipolar plate, a membrane, a sub-electrode frame and an electrode, the end electrode frames are arranged at opposite ends of the single cell assembly stacked in sequence, and in the projection direction of the bipolar plate and the current collector: the electrode reaction area of the bipolar plate of the single cell at the opposite ends of the stack is projected in the projection area of the current collector, and the current collector is arranged separately from the end electrode frame. In the high-power stack for the vanadium battery provided in the application, in the projection direction of the bipolar plate and the current collector: the electrode reaction area of the bipolar plate of the single cell at the opposite ends of the stack is projected in the projection area of the current collector, and the current collector is arranged separately from the end electrode frame, so that the electrode reaction area of the bipolar plate is prevented from being pressed and damaged by the current collector, and therefore, the safety of the high-power stack for the vanadium battery provided in the application is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery energy storage, in particular to a high-power stack for vanadium battery. BACKGROUND

[0002] The high-power stack for vanadium battery, for example, is a 25kW product. Figure 1 and Figure 2 As shown in the drawings, the electrode frame structure of the stack does not play a sealing and supporting role at the edge, and only the sealing ribs and grooves contact each other between the adjacent electrode frames 01 of the assembled stack. When the number of stack sheets increases and the electrolyte is full, sagging occurs at the middle position of the stack.

[0003] At the same time, the sealing assembly of the stack is sealed by a sealing ring at the end, and the outer sealing of the last sheet of the stack is achieved by pressing the sealing ring by the end bipolar plate and the electrode frame 01 of the last sheet. The sealing ring is installed in the sealing groove of the electrode frame of the last sheet, and then the end current collector is installed. The end current collector needs to be well attached to the end bipolar plate to realize conduction. The end current collector is a rectangular copper plate with a size of 1-2mm, which is smaller than the end bipolar plate and smaller than the electrode reaction area. Since the end current collector is a copper plate, it is difficult to meet the requirement of flatness, and the four corners may be raised, which may cause the end current collector to press the end bipolar plate and cause the end bipolar plate to crack after a long time, resulting in a risk of electrolyte leakage, thereby reducing the use safety of the high-power stack for vanadium battery.

[0004] Therefore, how to improve the use safety of the high-power stack for vanadium battery is a technical problem to be solved by those skilled in the art. SUMMARY

[0005] The purpose of the present application is to provide a high-power stack for vanadium battery, which improves the use safety of the high-power stack for vanadium battery.

[0006] To achieve the above-mentioned purpose, the present application provides a high-power stack for vanadium battery, comprising a current collector, an end electrode frame and single cells stacked in sequence, wherein the single cell comprises an electrode frame, a bipolar plate, a membrane, a sub-electrode frame and an electrode, the end electrode frame is arranged at opposite ends of the single cell assembly stacked in sequence, and the electrode reaction area of the bipolar plate of the single cell at the opposite ends of the stack is projected in the projection area of the current collector in the projection direction of the bipolar plate and the current collector, and the current collector and the end electrode frame are arranged separately.

[0007] Preferably, the outer periphery of the electrode frame is provided with a reinforcing rib outwardly protruding, and the reinforcing ribs of two adjacent electrode frames abut.

[0008] Preferably, the reinforcing rib is integrally formed with the electrode frame.

[0009] Preferably, the reaction area of the single cell is 1800cm2 -2500cm 2 , the single cell thickness is 2.5 mm -4.5mm.

[0010] Preferably, the number of sheets of the single cell of the stack is 120 sheets-150 sheets.

[0011] Preferably, the proton exchange membrane thickness of the stack is 25 μm -55 μm.

[0012] Preferably, the thickness of the electrode is 3 mm -6mm.

[0013] Preferably, the flow channel length of the single cell is 1.5 m -2.5m.

[0014] In the above technical solution, the high-power stack for vanadium battery provided by the application comprises a current collector, an end electrode frame, and single cells stacked in sequence, the single cell comprises an electrode frame, a bipolar plate, a membrane, a sub-electrode frame, and an electrode, the end electrode frame is arranged at opposite ends of the single cell assembly stacked in sequence, and the electrode reaction area of the bipolar plate of the single cell at the opposite ends of the stack is projected into the projection area of the current collector in the projection direction of the bipolar plate and the current collector stacked in sequence, and the current collector is isolated from the end electrode frame.

[0015] As can be seen from the above description, in the high-power stack for vanadium battery provided by the application, the electrode reaction area of the bipolar plate of the single cell at the opposite ends of the stack is projected into the projection area of the current collector in the projection direction of the bipolar plate and the current collector stacked in sequence, and the current collector is isolated from the end electrode frame, thereby avoiding the electrode reaction area of the bipolar plate being crushed by the current collector, and thus the safety of the high-power stack for vanadium battery provided by the application is improved. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description only constitute the embodiments of the application, and for those skilled in the art, other drawings can also be obtained without creative labor based on the provided drawings.

[0017] Figure 1 is a traditional adjacent electrode frame edge structure position diagram;

[0018] Figure 2 is a traditional end electrode frame mounting position diagram;

[0019] Figure 3 is a three-dimensional structure diagram of the stack provided by the embodiment of the application;

[0020] Figure 4 is a front view of the stack provided by the embodiment of the application;

[0021] Figure 5 A side view of the stack provided by the embodiment of the present application;

[0022] Figure 6 An end seal position exploded view of the stack provided by the embodiment of the present application;

[0023] Figure 7 An exploded view of the current collector and the single cell provided by the embodiment of the present application;

[0024] Figure 8 A position view of the adjacent electrode frame edge structure provided by the embodiment of the present application;

[0025] Figure 9 A partial enlarged three-dimensional structure view of the current collector and the single cell provided by the embodiment of the present application;

[0026] Figure 10 A partial sectional view of the current collector and the single cell provided by the embodiment of the present application;

[0027] Figure 11 A partial installation position view of the current collector and the single cell provided by the embodiment of the present application.

[0028] Wherein Figures 1-11 The core of the present application is to provide a high-power stack for vanadium battery, which improves the safety in use.

[0029] 01-electrode frame, 02-installation position

[0030] 1-single cell, 2-current collector, 3-electrode frame, 4-stiffener, 5-sealing ring, 6-end bipolar plate, 7-sub-electrode frame, 8-electrode, 9-end electrode frame, 10-end plate. DETAILED DESCRIPTION

[0031] The core of the present application is to provide a high-power stack for vanadium battery, which improves the safety in use.

[0032] In order for those skilled in the art to better understand the technical solutions of the present application, the present application will be further described in detail below in combination with the drawings and embodiments.

[0033] Please refer to Figures 3 to 11 .

[0034] In a specific embodiment, the high-power stack for vanadium battery provided by the embodiment of the present application comprises a current collector 2, an end electrode frame and single cells 1 stacked in sequence. The single cell 1 comprises an electrode frame 3, a bipolar plate, a membrane, a sub-electrode frame 7 and an electrode 8. The end electrode frame 9 is arranged at opposite ends of the single cell 1 assembly stacked in sequence, i.e. there are two end electrode frames 9, and one end electrode frame 9 is arranged at each of the opposite ends after the single cell 1 is assembled in sequence.

[0035] In the projection direction of the bipolar plate and the current collector 2: the electrode reaction area of the bipolar plate of the single cell 1 at the opposite ends of the stack is projected in the projection area of the current collector 2, and the current collector 2 is isolated from the end electrode frame 9.

[0036] In the specific manufacturing, the size of the end current collector 2 is increased to completely cover the electrode reaction area without affecting the structure of the end sealing ring 5. In the specific processing, only the edge of the inner area of the electrode frame 3 is trimmed, a gap is provided between the end current collector 2 and the end electrode frame 9, and the length and width of the end current collector 2 can be increased.

[0037] As described above, in the high-power stack for vanadium battery provided in the application, in the projection direction of the bipolar plate and the current collector 2: the electrode reaction area of the bipolar plate of the single cell 1 at the opposite ends of the stack is projected in the projection area of the current collector 2, and the current collector 2 is isolated from the end electrode frame 9. The combination part of the end current collector 2 and the end electrode frame 9 is moved to the position supported by the sub-electrode frame 7, the edge of the current collector 2 is on the sub-electrode frame 7, the end current collector 2 is in the center of the end electrode frame 9, and it is suspended relative to the end electrode frame 9. When the stack is pressed, the pressure is transmitted to the electrode frame and the sub-electrode frame 7, and the end bipolar plate 6 will not be cracked. Therefore, the use safety of the high-power stack for vanadium battery provided in the application is improved.

[0038] In a specific embodiment, the outer periphery of the electrode frame 3 is externally convexly provided with a reinforcing rib 4, and the reinforcing ribs 4 of two adjacent electrode frames 3 abut.

[0039] Specifically, the reinforcing rib 4 is located on one side of the electrode frame 3, or reinforcing ribs 4 are provided on both sides of the electrode frame 3. In order to improve the processing efficiency, the reinforcing rib 4 is preferably integrally formed with the electrode frame 3. By providing the reinforcing rib 4, the edge thickness of the electrode frame 3 is increased, and the edges of adjacent electrode frames are tightly fitted when the stack is pressed. In principle, it only plays a supporting role, and the sealing of the stack is still in the internal rib groove. Through actual electrolyte filling test, the middle of the stack does not sag, and this structure can also increase the number of stack pieces.

[0040] In a specific embodiment, the reaction area of the single cell 1 is 1800cm 2 -2500cm 2 , and the thickness of the single cell 1 is 2.5mm -4.5mm. Specifically, the thickness of the single cell 1 can be 3mm-4mm. The number of single cells 1 of the stack is 120-150, and specifically, the number of single cells 1 of the stack is 130-140. The biggest advantage is to improve the efficiency of the battery, and more than 90% of the components of the previous generation 25kW stack can be shared.

[0041] The application increases the reaction area of the single cell 1 by 20%, thins the single cell by 25%, increases the number of stack pieces by 30%, and increases the operating current density by more than 50%. In terms of battery parameters, the power is more than one time of the existing product, 50kW, and the maximum can reach 100kW. The voltage is increased from the existing 140V to 190-230V, and the current is increased from 140A to 330A-370A, and the maximum can run to 450A. That is, through structural optimization and the increase of current density, the single stack power is 50kW-100kW, the efficiency is more than 85%, and the current density is increased by 50% compared with the existing product.

[0042] In one specific embodiment, the proton exchange membrane of the stack has a thickness of 25μm-55μm. Specifically, the proton exchange membrane has a thickness of 35μm-45μm.

[0043] The thickness of the electrode 8 is 3mm-6mm, and specifically, the thickness of the electrode 8 is 4mm-5mm. Reducing the resistance, at the same time, thinning the thickness of the vanadium cell reaction electrode 8 and modifying the electrode 8 material itself to reduce the resistance, the test proves that the efficiency of the changed stack is higher than the existing product, and the operable current density is higher.

[0044] On the basis of the above-mentioned schemes, the flow channel length of the single cell 1 is 1.5m-2.5m, and specifically, the flow channel length of the single cell 1 is 1.7m-2.3m. The application replaces the function of the coil in the stack by increasing the inlet and outlet liquid flow channel length of the single cell 1. The inlet coil is cancelled in the stack, the reaction area of the single cell 1 of the stack is larger, the number of stack pieces is more than the existing one, and the power is more than twice of the existing one. The application only needs to slightly change the electrode frame inlet and outlet liquid flow channel of the single cell 1 by increasing the flow channel length of the single cell 1. The flow channel structure of the electrode frame 3 and the end electrode frame 9 is the same, except that the internal reaction area of the end electrode frame 9 is less than that of the electrode frame 3. Figure 10 As shown in the figure.

[0045] The growth of the flow channel length depends on the size of the electrode frame 3. The electrode frame 3 of the application is 20% larger than the existing one, so the flow channel length is correspondingly increased. The connection mode of the electrode frame 3 and other components is unchanged. Since the electrode frame is a PP injection product, it is easy to realize. The electrode frame adopts a self-sealing form of rib and groove interlocking. The rib and groove interlocking refers to the fact that the electrode frame or the end electrode frame itself has a rib and groove interlocking structure. One side of the electrode frame or the end electrode frame is a rib surface, and the other side is a groove surface. By pressing the adjacent electrode frame or end electrode frame, the rib is embedded into the groove of the other one, so as to realize sealing, and there is no risk of leakage.

[0046] Each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between each embodiment can be referred to each other.

[0047] The foregoing description of the disclosed embodiments enables one skilled in the art to make or use the application. Numerous modifications of those embodiments can be apparent to those skilled in the art, and the generic principles defined herein can be applied to other embodiments without the use of the innovation falling outside the spirit and scope of the application. Therefore, the application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A high-power fuel cell stack for vanadium batteries, characterized in that, The assembly includes a current collector (2), an end electrode frame (9), and a single cell (1) stacked sequentially. The single cell (1) includes an electrode frame (3), a bipolar plate, a membrane, a sub-electrode frame, and an electrode (8). The end electrode frame (9) is arranged at opposite ends of the stacked single cell (1) assembly. Projected along the stacking direction of the bipolar plate and the current collector (2): the electrode reaction region of the bipolar plate of the single cell (1) located at opposite ends of the stack is projected within the projection region of the current collector (2). The part where the current collector (2) and the end electrode frame (9) are joined is moved to a position supported by the sub-electrode frame. The edge of the current collector (2) is on the sub-electrode frame. The current collector (2) and the end electrode frame (9) are isolated from each other.

2. The high-power vanadium battery stack according to claim 1, characterized in that, The outer periphery of the electrode frame (3) is provided with reinforcing ribs (4), and the reinforcing ribs (4) of two adjacent electrode frames (3) abut against each other.

3. The high-power vanadium battery stack according to claim 2, characterized in that, The reinforcing rib (4) is integrally formed with the electrode frame (3).

4. The high-power vanadium battery stack according to claim 1, characterized in that, The reaction area of ​​a single cell (1) is 1800cm2-2500cm2, and the thickness of a single cell (1) is 2.5 mm-4.5 mm.

5. The high-power vanadium battery stack according to claim 1, characterized in that, The number of individual cells (1) in the stack is 120-150.

6. The high-power vanadium battery stack according to claim 1, characterized in that, The proton exchange membrane thickness of the fuel cell stack is 25 μm - 55 μm.

7. The high-power vanadium battery stack according to claim 1, characterized in that, The thickness of the electrode (8) is 3mm-6mm.

8. The high-power vanadium battery stack according to claim 1, characterized in that, The flow channel length of the single cell (1) is 1.5 m - 2.5 m.

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