Bipolar plate and bipolar battery

Abstract

The bipolar plate comprises a conductive substrate, a first conductive layer and a second conductive layer are respectively arranged on the front surface and the back surface of the conductive substrate, and the first conductive layer is formed by welding a conductive network on the front surface of the conductive substrate and / or spraying or plating conductive particles on the front surface of the conductive substrate; the second conductive layer is formed by welding a conductive network on the reverse side of the conductive substrate and / or spraying or plating conductive particles on the reverse side of the conductive substrate; a positive active material layer is loaded on the surface of the first conductive layer, a negative active material layer is loaded on the surface of the second conductive layer, and the first conductive layer and the second conductive layer are rolled to form a whole. The arrangement of the first conductive layer and the second conductive layer provides a good adhesion basis for the positive active material layer and the negative active material layer, the roughness and the specific surface area of the surface of the bipolar plate are increased by the conductive network and the conductive particles, so that the active material can be better adhered to the bipolar plate, and the active material can be better adhered to the bipolar plate through rolling treatment. The active material can be more tightly combined with the conductive layer to form a whole, so that the binding force between the bipolar plate and the electrode material is enhanced, the high-power charge-discharge performance of the battery is improved, the stability of the battery structure is ensured, and the performance and the cycle life of the battery are further improved.

Description

Technical Field

[0001] This utility model belongs to the field of secondary batteries and relates to a bipolar plate and a bipolar battery. Background Technology

[0002] Nickel-metal hydride (NiMH) batteries, as a type of green and environmentally friendly rechargeable battery, have advantages such as high energy density, long cycle life, and no memory effect, and are widely used in electric vehicles, portable electronic devices, and other fields. Currently, NiMH batteries have a relatively low energy density (60–120 Wh / kg) due to their voltage of 1.2–1.3V, while bipolar NiMH batteries have a higher energy density (150–200 Wh / kg), approaching the level of lithium-ion batteries (150–250 Wh / kg).

[0003] Bipolar plates are one of the key components of nickel-metal hydride (NiMH) batteries, and their performance directly affects the overall performance of the battery. Traditional NiMH battery bipolar plates suffer from problems such as poor conductivity and insufficient bonding with electrode materials, leading to increased internal resistance and reduced charge-discharge efficiency, which in turn affects the battery's performance and lifespan. Utility Model Content

[0004] The purpose of this invention is to provide a bipolar plate and a bipolar battery to solve the technical problems of poor conductivity and insufficient bonding force of electrode materials in existing bipolar plates, thereby improving the performance and cycle life of nickel-metal hydride batteries.

[0005] The technical solution of this utility model is as follows:

[0006] This utility model provides a bipolar plate, including a conductive substrate. The front and back sides of the conductive substrate are respectively provided with a first conductive layer and a second conductive layer. The first conductive layer is formed by welding a conductive network on the front side of the conductive substrate and / or spraying or plating conductive particles on the front side of the conductive substrate.

[0007] The second conductive layer is formed by welding a conductive network to the reverse side of a conductive substrate, and / or by spraying or plating conductive particles on the reverse side of a conductive substrate.

[0008] The surface of the first conductive layer is loaded with a positive electrode active material layer, and the surface of the second conductive layer is loaded with a negative electrode active material layer. They are formed into a whole by rolling.

[0009] The technical effects of the above-mentioned technical solution are as follows: The setting of the first and second conductive layers provides a good adhesion base for the positive and negative active material layers. The conductive network and conductive particles increase the surface roughness and specific surface area of ​​the bipolar plate, allowing the active material to adhere better to the bipolar plate. Through the rolling process, the active material can be more tightly bonded to the conductive layer to form a whole, thereby enhancing the bonding force between the bipolar plate and the electrode material. This tight bonding can effectively prevent the active material from falling off during battery charging and discharging, enhance the conductive interface between the active material and the bipolar plate, improve the high-power charging and discharging performance of the battery, ensure the stability of the battery structure, and thus improve the battery performance and cycle life.

[0010] As a further improvement to the above technical solution, the conductive substrate is a metal substrate, preferably a composite plate of one or two of the following materials: nickel-plated steel plate, nickel-plated copper plate, nickel plate, and stainless steel plate.

[0011] As a further improvement to the above technical solution, the conductive network includes a composite network of one or two of the following materials: nickel mesh, copper mesh, stainless steel mesh, nickel-plated steel mesh, titanium-plated steel mesh, titanium mesh, and carbon-plated steel mesh.

[0012] The technical effects of the above solution are as follows: By welding conductive networks on both sides of the conductive substrate, these metal networks have good conductivity and can form efficient electron conduction channels within the bipolar plate, reducing the resistance of electron transmission. Compared with traditional bipolar plates, electrons can flow more quickly and smoothly within the plates, thereby effectively improving the overall conductivity of the bipolar plate, reducing the internal resistance of the battery, and improving the charging and discharging efficiency of the battery.

[0013] As a further improvement to the above technical solution, the conductive particles are carbon-based conductive particles or metal conductive particles, preferably one or more of carbon black, graphene, carbon nanotubes, silver powder, nickel powder, cobalt powder, and titanium powder.

[0014] The technical effects of the above-mentioned technical solution are as follows: By spraying or plating conductive particles on both sides of the conductive substrate, the conductivity of the bipolar plate can be further enhanced. At the same time, the surface of the conductive substrate can be roughened to enhance the bonding force between the electrode material and the conductive substrate, preventing the active material from peeling off or falling off from the conductive substrate. Carbon-based conductive particles have a large specific surface area and good electron mobility, which can fill the gaps between the conductive substrate and the conductive network to form additional conductive paths. Metal conductive particles, with their excellent conductivity, further optimize the electron conduction path, thereby significantly improving the conductivity of the bipolar plate.

[0015] As a further improvement to the above technical solution, the welding portion between the conductive network and the conductive substrate is elongated, and the number of welding portions is several, with the welding portions located along the length direction of the conductive substrate; the cross-sectional area of ​​the conductive network is less than or equal to the cross-sectional area of ​​the conductive substrate.

[0016] The technical effects of the above solution are as follows: By welding and fixing the conductive network to the conductive substrate through multiple horizontally arranged welding points, the connection stability between the conductive network and the conductive substrate is improved. At the same time, the conductive substrate is divided into several regions, and the region between two welding points is the active material loading region. There is no active material in the welding points, which helps to shorten the electron transmission distance and improve its high current charging and discharging capability.

[0017] This utility model also provides a bipolar battery, comprising a positive monopolar plate, the bipolar plate, a negative monopolar plate, and a separator disposed between the positive and negative electrodes. Attached Figure Description

[0018] To more clearly illustrate the technical solution of this utility model, the following figures provide a brief description. The figures described below are merely some examples of embodiments of this utility model; those skilled in the art can apply them based on the figures and actual production conditions without any creative effort.

[0019] Figure 1 This is a schematic diagram showing the positions of the conductive network and conductive substrate in Example 1;

[0020] Figure 2 This is a front view of the conductive substrate with the welded conductive network in Example 1;

[0021] Figure 3 for Figure 2 Side view;

[0022] Figure 4 This is a schematic diagram of spraying conductive particles 5 onto a conductive substrate of a welded conductive network in Example 1.

[0023] Figure 5 This is a schematic diagram of the bipolar plate in Example 1;

[0024] Figure 6 for Figure 5 A magnified view of a portion of the image;

[0025] Figure 7 This is a flowchart of the fabrication process of a bipolar plate.

[0026] Figure 8 This is a cross-sectional view of the main body of a bipolar nickel-metal hydride battery;

[0027] Labeling explanation: 1-Conductive substrate, 2-First conductive layer, 3-Second conductive layer, 4-Conductive network, 5-Conductive particles, 6-Positive electrode active material layer, 7-Negative electrode active material layer, 8-Welding part, 9-Sealing frame, 10-Separator, 11-Positive monopolar plate, 12-Negative monopolar plate. Detailed Implementation

[0028] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0029] It should be noted that the terms "up," "down," "left," "right," "front," and "back" used in this document to describe directions, unless otherwise specified, do not specifically refer to that direction. They are used merely for ease of description, and the descriptions may differ depending on the placement of the product. Any directions that can be understood by those skilled in the art without inventive effort are within the scope of protection of this utility model.

[0030] Example 1

[0031] like Figure 1-5 As shown, a bipolar plate includes a conductive substrate 1. A first conductive layer 2 and a second conductive layer 3 are respectively provided on the front and back sides of the conductive substrate 1. The first conductive layer 2 is formed by first welding a conductive network 4 on the front side of the conductive substrate 1, and then spraying or electroplating conductive particles 5.

[0032] The second conductive layer 3 is formed by first welding a conductive network 4 to the reverse side of a conductive substrate, and then spraying or electroplating conductive particles 5.

[0033] The surface of the first conductive layer is loaded with a positive electrode active material layer 6, and the surface of the second conductive layer is loaded with a negative electrode active material layer 7. They are formed into a whole by rolling.

[0034] In this embodiment, the conductive substrate 1 is a metal substrate, preferably a composite plate made of one or two of the following materials: nickel-plated steel plate, nickel-plated copper plate, nickel plate, and stainless steel plate. These metal substrates have good conductivity and a certain mechanical strength, and can provide a stable support structure for the subsequent conductive layer and active material.

[0035] In this embodiment, the conductive network 4 includes a composite mesh made of one or two of the following materials: nickel mesh, copper mesh, stainless steel mesh, nickel-plated steel mesh, titanium-plated steel mesh, titanium mesh, and carbon-plated steel mesh. These metal meshes have good conductivity. After being welded onto the conductive substrate, they can construct efficient electron conduction channels within the bipolar plate, greatly reducing the resistance during electron transport and significantly improving the overall conductivity of the bipolar plate.

[0036] In this embodiment, the conductive particles 5 are carbon-based conductive particles or metal conductive particles, preferably one or more of carbon black, graphene, carbon nanotubes, silver powder, nickel powder, cobalt powder, and titanium powder. The conductive particles can fill the gaps in the conductive substrate and conductive network, forming additional conductive pathways and further enhancing the conductivity of the bipolar plate. Simultaneously, spraying the conductive particles can roughen the surface of the conductive substrate, enhancing the adhesion to the electrode material and effectively preventing the active material from peeling off or falling off the conductive substrate during battery charging and discharging.

[0037] In this embodiment, conductive particles, binder, and solvent are dissolved and mixed evenly to form a conductive slurry, which facilitates the spraying of conductive particles onto both sides of the conductive substrate. Alternatively, the conductive particles can be thermally melted and then sprayed onto the conductive substrate using sputtering or spraying methods.

[0038] In this embodiment, the welding points 8 between the conductive network and the conductive substrate are elongated, and there are several welding points located along the length of the conductive substrate. The multiple laterally arranged welding points not only improve the connection stability between the conductive network and the conductive substrate but also divide the conductive substrate into several regions. The region between two welding points serves as an active material loading region, while the welding points themselves do not load active material. This design helps to shorten the electron transport distance and significantly improve the battery's high-current charge and discharge capability.

[0039] In this embodiment, the cross-sectional area of ​​the conductive network 4 is less than or equal to the cross-sectional area of ​​the conductive substrate 1.

[0040] like Figure 6 As shown, the method for preparing the above-mentioned bipolar plate includes:

[0041] Step 1: Prepare a first conductive layer on the front side of the conductive substrate, using any of the following methods:

[0042] 1.1 Directly weld the conductive network onto the front side of the polished and roughened conductive substrate; the increased surface roughness of the polished conductive substrate provides more adhesion sites for the welding points, making the welding stronger and enhancing the bonding force between the conductive network and the conductive substrate.

[0043] 1.2 Spray the adhesive containing conductive particles onto the front side of the polished conductive substrate, and then dry it to obtain the first conductive layer. During the spraying process, the rough surface of the conductive substrate can better adsorb the conductive particles, so that the conductive particles and the substrate surface form a mechanical bond, which enhances the bonding force between the conductive particles and the substrate and ensures the stability of the conductive layer.

[0044] 1.3 First, a conductive network is welded onto the front side of the polished conductive substrate. Then, an adhesive containing conductive particles is sprayed onto the front side of the substrate, and finally, it is dried. This method combines the advantages of welding and spraying, which can further improve the conductivity and stability of the first conductive layer.

[0045] Step 2: Prepare a second conductive layer on the reverse side of the conductive substrate:

[0046] Its preparation process is similar to that of the first conductive layer, and there are also three methods, each of which is performed on the reverse side of the conductive substrate.

[0047] Step 3: The positive electrode active material is uniformly coated onto the surface of the first conductive layer, and the negative electrode active material is uniformly coated onto the surface of the second conductive layer. Then, a rolling process is performed to ensure a tight bond between the positive electrode active material layer, the first conductive layer, the conductive substrate, the second conductive layer, and the negative electrode active material layer, ultimately resulting in a bipolar plate. The rolling process allows the active material to bond more tightly with the conductive layer, forming a stable overall structure, effectively improving battery performance and cycle life.

[0048] Example 2

[0049] like Figure 7 As shown, a bipolar nickel-metal hydride battery mainly consists of a positive monopolar plate 11, a bipolar plate, a negative monopolar plate 12, and a separator 10 disposed between the positive and negative electrodes. The positive monopolar plate 11 and the negative monopolar plate 12 are responsible for collecting current from the positive and negative electrodes of the battery, respectively. The bipolar plate plays a crucial role in connecting and conducting current within the battery. The separator 10 isolates the positive and negative electrodes, preventing short circuits and ensuring the safe and stable operation of the battery. The battery is sealed around its perimeter using a sealing frame 9. The remaining technical details are common knowledge in the art and will not be elaborated upon here.

[0050] The above description is merely a preferred embodiment of this utility model, and the protection scope of this utility model is not limited to the above embodiments. For those skilled in the art, improvements and modifications obtained without departing from the technical concept of this utility model should also be considered within the protection scope of this utility model.

Claims

1. A bipolar plate, comprising a conductive substrate, wherein a first conductive layer and a second conductive layer are respectively disposed on the front and back sides of the conductive substrate, characterized in that, The first conductive layer is formed by welding a conductive network to the front side of a conductive substrate and / or by spraying or plating conductive particles on the front side of a conductive substrate. The second conductive layer is formed by welding a conductive network to the reverse side of a conductive substrate, and / or by spraying or plating conductive particles on the reverse side of a conductive substrate. The surface of the first conductive layer is loaded with a positive electrode active material layer, and the surface of the second conductive layer is loaded with a negative electrode active material layer. They are formed into a whole by rolling.

2. The bipolar plate according to claim 1, characterized in that, The conductive substrate is a metal substrate, which is a composite plate made of one or two of the following materials: nickel-plated steel plate, nickel-plated copper plate, nickel plate, and stainless steel plate.

3. The bipolar plate according to claim 1, characterized in that, The conductive network includes a composite mesh made of one or two of the following materials: nickel mesh, copper mesh, stainless steel mesh, nickel-plated steel mesh, titanium-plated steel mesh, titanium mesh, and carbon-plated steel mesh.

4. The bipolar plate according to claim 1, characterized in that, The conductive particles are carbon-based conductive particles or metal conductive particles.

5. A bipolar plate according to claim 1, characterized in that, The welding points between the conductive network and the conductive substrate are elongated, and the number of welding points is several. The welding points are located along the length of the conductive substrate. The cross-sectional area of ​​the conductive network is less than or equal to the cross-sectional area of ​​the conductive substrate.

6. A bipolar battery, characterized in that, It includes a positive monopolar plate, a bipolar plate as described in any one of claims 1 to 5, a negative monopolar plate, and a diaphragm disposed between the positive and negative electrodes.

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