Metal-air battery and manufacturing method thereof

Abstract

The invention relates to the technical field of batteries, and provides a metal-air battery and a manufacturing method thereof, the metal-air battery comprises: a plurality of bipolar plates which are stacked in sequence; the liquid cavities are arranged between every two adjacent bipolar plates, each liquid cavity is provided with a first side and a second side which respectively face the two adjacent bipolar plates, and the first side is in sealed connection with the bipolar plate close to the first side through welding; the positive plate is arranged between the second side and the bipolar plate close to the second side, one side of the positive plate is connected with the bipolar plate in a hot pressing manner through a conductive adhesive, and the other side of the positive plate is connected with the second side in a sealing and pressing manner through an alkali-resistant material. According to the metal-air battery, reliable sealing connection between the two sides of the liquid cavity and the bipolar plate and the positive plate is guaranteed, the structural reliability is high, electrolyte leakage is prevented, the cycle service life of the battery is prolonged, meanwhile, the size of the battery is reduced, the energy efficiency is improved, and continuous production is facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and particularly to a metal-air battery and a manufacturing method thereof. Background Art

[0002] A metal-air battery is an efficient and environmentally friendly chemical power source, whose principle is based on the electrochemical reaction between a metal and oxygen in the air to achieve the conversion of chemical energy into electrical energy. For example, zinc-air batteries are regarded as a potential direction for next-generation energy storage technologies due to their advantages such as high energy density, low raw material cost, and environmental friendliness, and have broad application prospects especially in fields such as micro energy storage systems, portable electronic devices, and Internet of Things terminals.

[0003] Traditional metal-air batteries are usually assembled by mechanical pressing or sealant encapsulation. Mechanical pressing relies on physical pressure to maintain component contact, and long-term vibration or temperature fluctuations are likely to cause component loosening, resulting in electrolyte leakage, low structural reliability, and affecting the cycle service life. Sealant encapsulation is prone to corrosion cracking due to thermal cycling or chemical reactions, causing electrolyte leakage and short seal life. Summary of the Invention

[0004] The present invention provides a metal-air battery and a manufacturing method thereof to solve the problem that the assembly method of the metal-air battery in the prior art is prone to electrolyte leakage.

[0005] The present invention provides a metal-air battery and a manufacturing method thereof, including: Multiple bipolar plates, which are stacked in sequence; A liquid cavity is provided between every two adjacent bipolar plates. The liquid cavity has a first side and a second side respectively facing the adjacent two bipolar plates. The first side is hermetically connected to the bipolar plate close to it by welding. A positive electrode sheet is provided between the second side and the bipolar plate close to it. One side of the positive electrode sheet is thermocompression bonded to the bipolar plate by a conductive adhesive, and the other side of the positive electrode sheet is hermetically pressed with the second side by an alkali-resistant material.

[0006] According to a metal-air battery provided by the present invention, it further includes: A negative electrode metal sheet is provided between the first side and the bipolar plate close to it. The negative electrode metal sheet is thermocompression bonded to the bipolar plate by a conductive adhesive.

[0007] According to a metal-air battery provided by the present invention, the outer peripheral edge of the negative electrode metal sheet is pressed between the liquid cavity and the bipolar plate.

[0008] A metal-air battery provided according to the present invention, the bipolar plate for welding with the liquid chamber includes: a plate body and a conductive metal foil, the conductive metal foil is thermally pressed and joined with the plate body through the conductive adhesive, a negative electrode metal paste is coated on the conductive metal foil, and the negative electrode metal paste is received in a receiving space formed by enclosing the conductive metal foil, the liquid chamber and the positive electrode sheet; A separator is provided between the positive electrode sheet and the liquid chamber adjacent to it, one side of the separator is sealed and pressed with the positive electrode sheet through an alkali-resistant material, and the other side of the separator is sealed and pressed with the second side through an alkali-resistant material.

[0009] A metal-air battery provided according to the present invention, the alkali-resistant material is hot melt adhesive, alkali-resistant adhesive or carbon fiber board.

[0010] A metal-air battery provided according to the present invention, a gas flow channel is provided on the bipolar plate adjacent to the positive electrode sheet, and the gas flow channel is located on the side of the bipolar plate close to the positive electrode sheet.

[0011] A metal-air battery provided according to the present invention, the plurality of bipolar plates include: a first bipolar plate, a second bipolar plate and a third bipolar plate, at least one of the third bipolar plates is stacked between the first bipolar plate and the second bipolar plate, and inspection structures are provided on the first bipolar plate and the second bipolar plate.

[0012] The present invention also provides a method for manufacturing a metal-air battery, including the steps of: Welding and sealingly connecting the first bipolar plate with the first side of a liquid chamber to obtain a first component; Thermally pressing and joining the second bipolar plate with a positive electrode sheet through a conductive adhesive to obtain a second component; Thermally pressing and joining one side of the third bipolar plate with a positive electrode sheet through a conductive adhesive, and welding and sealingly connecting the other side of the third bipolar plate with the first side of a liquid chamber to obtain a third component; Sealing and pressing the second side of the liquid chamber in the first component with the positive electrode sheet in the third component through an alkali-resistant material, and sealing and pressing the second side of the liquid chamber in the third component with the positive electrode sheet in the second component through an alkali-resistant material.

[0013] A method for manufacturing a metal-air battery provided according to the present invention, before welding and sealingly connecting the first bipolar plate with the first side of a liquid chamber, further includes: thermally pressing and joining the first bipolar plate with a negative electrode metal sheet through a conductive adhesive; Before welding and sealingly connecting the other side of the third bipolar plate with the first side of a liquid chamber, further includes: thermally pressing and joining the other side of the third bipolar plate with a negative electrode metal sheet through the conductive adhesive.

[0014] According to a method for manufacturing a metal-air battery provided by the present invention, a plurality of the third components are manufactured, and a plurality of the third components are stacked between the first component and the second component, and each adjacent two of the third components are hermetically pressed together by an alkali-resistant material.

[0015] For the metal-air battery and its manufacturing method provided by the present invention, by welding one side of the liquid chamber to the bipolar plate, hermetically pressing the other side of the liquid chamber to the positive electrode plate by an alkali-resistant material, and thermally pressing and bonding the positive electrode plate to the bipolar plate by a conductive adhesive, it is ensured that both sides of the liquid chamber are reliably sealed and connected to the bipolar plate and the positive electrode plate respectively, with high structural reliability, preventing electrolyte leakage, and improving the cycle service life of the battery; welding the liquid chamber and the bipolar plate eliminates the need for additional sealant, and the high-strength adhesiveness of the conductive adhesive can achieve a tight connection between the positive electrode plate and the bipolar plate and reduce the thickness of the adhesive layer, thereby reducing the volume of the battery; a thinner conductive adhesive thickness can avoid glue overflow and shorten the curing time, facilitating continuous production; the conductive adhesive can also reduce the internal resistance loss of the battery and improve the energy efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0017] Figure 1 is one of the exploded structural schematic diagrams of the metal-air battery provided by the present invention.

[0018] Figure 2 is Figure 1 another perspective schematic diagram of the exploded structure of the metal-air battery in

[0019] Figure 3 is one of the component exploded schematic diagrams of the exploded structure of the metal-air battery provided by the present invention.

[0020] Figure 4 is the second exploded structural schematic diagram of the metal-air battery provided by the present invention.

[0021] Figure 5 is Figure 4 another perspective schematic diagram of the exploded structure of the metal-air battery in

[0022] Figure 6 is the second component exploded schematic diagram of the exploded structure of the metal-air battery provided by the present invention.

[0023] Reference Signs: 1. Bipolar plate; 11. Plate body; 12. Conductive metal foil; 13. Gas flow channel; 1a. First bipolar plate; 1b. Second bipolar plate; 1c. Third bipolar plate; 2. Liquid cavity; 21. First side; 22. Second side; 3. Positive electrode plate; 4. Negative metal sheet; 5. Negative metal paste; 6. Separator; 100. First component; 200. Second component; 300. Third component. Detailed implementation mode

[0024] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below with reference to the accompanying drawings in the present invention. Apparently, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without creative efforts shall fall within the protection scope of the present invention.

[0025] In the description of the embodiments of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "first", "second", and "third" are used for numbering product components for clear description and do not represent any substantial difference. The terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances. In addition, the meaning of "a plurality" is two or more.

[0026] The following will be combined with Figures 1-6 Describe the metal-air battery and its manufacturing method of the present invention.

[0027] As Figure 1 and Figure 2 shown, the metal-air battery provided by the embodiment of the present invention includes a liquid cavity 2, a positive electrode plate 3, and a plurality of bipolar plates 1. The plurality of bipolar plates 1 are stacked in sequence. A liquid cavity 2 is provided between every two adjacent bipolar plates 1. The liquid cavity 2 has a first side 21 and a second side 22 respectively facing the two adjacent bipolar plates 1. The first side 21 is hermetically connected to the adjacent bipolar plate 1 by welding, and a positive electrode plate 3 is provided between the second side 22 and the adjacent bipolar plate 1. One side of the positive electrode plate 3 is thermally pressed and joined to the bipolar plate 1 through a conductive adhesive, and the other side of the positive electrode plate 3 is hermetically pressed and joined to the second side 22 through an alkali-resistant material.

[0028] Among them, the liquid cavity 2 is a ring structure, as Figure 1In the shown rectangular ring structure, bipolar plates 1 and a positive electrode plate 3 are respectively connected to both sides of the liquid chamber 2 to enclose a containing space. The two side surfaces of the liquid chamber 2 are parallel to each other, making the thickness of the containing space uniform and optimizing the stability of electrolyte distribution. On the side of the positive electrode plate 3 away from the liquid chamber 2, another bipolar plate 1 is connected, and this another bipolar plate 1 is used to provide structural support for the positive electrode plate 3. A liquid injection port is provided on the liquid chamber 2, and electrolyte is injected into the containing space through the liquid injection port.

[0029] This metal-air battery can be a zinc-air battery, a lithium-air battery, a magnesium-air battery, etc. Taking the zinc metal-air battery as an example, the electrolyte includes but is not limited to aqueous solvents such as KOH and (CH3COO) 2 Zn. Optionally, the concentration of KOH is selected as 6 mol / L, and the concentration of (CH3COO) 2 Zn is 0.2 mol / L.

[0030] The number of bipolar plates 1 is at least two. When the number of bipolar plates 1 is two, there is one liquid chamber 2 between the two bipolar plates 1, and a positive electrode plate 3 is provided between the liquid chamber 2 and one of the bipolar plates 1, thereby forming a metal-air battery structure with only a single cell. When a battery with a larger capacity is needed, more bipolar plates 1 can be set. One liquid chamber 2 and one positive electrode plate 3 are provided between every two adjacent bipolar plates 1 to form a metal-air battery structure with multiple cells connected in series. Every two adjacent cells share one bipolar plate 1. Define the side of the bipolar plate 1 for connecting the positive electrode plate 3 as the positive electrode side, and the side for connecting the negative metal as the negative electrode side.

[0031] Among them, the liquid chamber 2 and the bipolar plate 1 are hermetically connected by welding, which can ensure reliable sealing connection between the two, and it is not easy for the components to loosen due to long-term vibration or temperature fluctuation. Optionally, the material of the liquid chamber 2 is transparent or semi-transparent polypropylene material, and the material of the bipolar plate 1 is non-transparent polypropylene-based composite material. The two can be welded from the side of the liquid chamber 2 by a laser welding process. The bipolar plate 1 and the liquid chamber 2 can also be other materials suitable for laser welding, such as a combination of polyolefin-based, fluoropolymer-based or their modified materials.

[0032] It should be noted that the liquid chamber 2 and the bipolar plate 1 are not limited to being welded by a laser welding process. For example, they can also be welded by a thermoplastic welding process. The embodiments of the present invention do not specifically limit the materials of the bipolar plate 1 and the liquid chamber 2, and can be selected according to actual conditions and needs, as long as the material of the joint surface of the bipolar plate 1 and the liquid chamber 2 is adapted to the corresponding welding process.

[0033] The positive electrode sheet 3 serves as an air electrode and can be selected as carbon paper, such as the carbon paper of the Freudenberg H24CX483 model. Its surface contains polytetrafluoroethylene (PTFE), and PTFE has hydrophobic properties, which can reduce the hydrophilicity of the carbon paper surface, making the carbon paper have a hydrophobic effect, effectively isolating the electrolyte, and only realizing the transmission of air. Of course, the positive electrode sheet 3 can also use other carbon-based materials or non-carbon materials, and the embodiments of the present invention do not limit this.

[0034] The joint surface between the liquid chamber 2 and the positive electrode sheet 3 is sealed and pressed by an alkali-resistant material. Optionally, the alkali-resistant material is hot melt adhesive, alkali-resistant glue or carbon fiber board. Among them, the hot melt adhesive uses alkali-resistant hot melt adhesive, and the hot melt adhesive or carbon fiber board makes the liquid chamber 2 and the positive electrode sheet 3 be sealed and joined through a hot pressing process. The alkali-resistant glue makes the liquid chamber 2 and the positive electrode sheet 3 be sealed and joined through a normal temperature pressing process. Of course, the embodiments of the present invention do not specifically limit the alkali-resistant material, and it can be selected according to actual conditions and needs, as long as it can meet the requirements of not reacting with the electrolyte and enabling the sealed joint of the liquid chamber 2 and the positive electrode sheet 3.

[0035] The joint surface between the side of the positive electrode sheet 3 away from the liquid chamber 2 and the bipolar plate 1 is hot-pressed and joined by a conductive adhesive. The conductive adhesive is a material with both conductivity and adhesiveness. The conductive adhesive can reduce the internal resistance loss of the battery during charge and discharge, improving the energy efficiency; and the conductive adhesive has high adhesive strength, which can greatly reduce the thickness of the adhesive layer to avoid glue overflow, and has a short curing time, making it easy to adapt to continuous production, which is beneficial to the miniaturized design of the battery volume.

[0036] The metal-air battery provided by the embodiments of the present invention ensures reliable sealed connections between the two sides of the liquid chamber 2 and the bipolar plate 1 and the positive electrode sheet 3 respectively by welding one side of the liquid chamber 2 to the bipolar plate 1, sealing and pressing the other side of the liquid chamber 2 to the positive electrode sheet 3 through an alkali-resistant material, and hot-pressing and joining the positive electrode sheet 3 to the bipolar plate 1 through a conductive adhesive. It has high structural reliability, prevents electrolyte leakage, and improves the cycle service life of the battery; welding the liquid chamber 2 and the bipolar plate 1 does not require additional sealant, and the high-strength adhesiveness of the conductive adhesive can achieve a tight connection between the positive electrode sheet 3 and the bipolar plate 1 and reduce the thickness of the adhesive layer, thereby reducing the volume of the battery; a thinner conductive adhesive thickness can avoid glue overflow and shorten the curing time, which is beneficial to continuous production; the conductive adhesive can also reduce the internal resistance loss of the battery and improve the energy efficiency. The metal-air battery provided by the embodiments of the present invention provides a lightweight and long-endurance power solution, and at the same time lays a key technical foundation for the large-scale application of metal-air batteries under complex working conditions.

[0037] Verified by experiments, compared with the metal-air battery with a traditional structure, the electrolyte leakage rate of the metal-air battery provided by the embodiment of the present invention is reduced from 5% to less than 0.5%, and the service life is significantly improved; the volume is reduced by 15% and the thickness is thinned by 15%; the use of the laser welding process shortens the assembly cycle by 30% compared with manual mechanical pressing.

[0038] The metal-air battery provided by the embodiment of the present invention further includes a negative electrode metal sheet 4. A negative electrode metal sheet 4 is provided between the first side 21 of the liquid chamber 2 and the bipolar plate 1 adjacent thereto. The negative electrode metal sheet 4 and the bipolar plate 1 are thermocompression bonded through a conductive adhesive. That is, the negative electrode side of the bipolar plate 1 and the negative electrode metal sheet 4 are thermocompression bonded through a conductive adhesive and welded to the liquid chamber 2, and the positive electrode side of the bipolar plate 1 and the positive electrode sheet 3 are thermocompression bonded through a conductive adhesive.

[0039] Optionally, the negative electrode metal sheet 4 is a zinc sheet, a lithium sheet, a magnesium sheet, etc. The negative electrode metal sheet 4 and the bipolar plate 1 are thermocompression bonded through a conductive adhesive, which can reduce the internal resistance loss during the charge and discharge process of the battery and improve the energy efficiency. The conductive adhesive with high bonding strength can greatly reduce the thickness of the adhesive layer to avoid glue overflow, and has a short curing time, is easy to adapt to continuous production, and is beneficial to the miniaturized design of the battery volume.

[0040] It should be noted that when the bipolar plate 1 is made of a material that does not react with the electrolyte, for example, the bipolar plate 1 is a polypropylene bipolar plate, the negative electrode metal sheet 4 may not be provided additionally. During battery charging, metal ions in the electrolyte will be reduced and attached to the polypropylene bipolar plate, and then discharge occurs.

[0041] As Figure 1 and Figure 2 As shown in

[0042] As Figure 4 and Figure 5As shown in the figure, in some other embodiments of the present invention, the bipolar plate 1 for welding with the liquid chamber 2 includes a plate body 11 and a conductive metal foil 12. The conductive metal foil 12 is thermocompression bonded to the plate body 11 through a conductive adhesive, and a negative electrode metal paste 5 is coated on the conductive metal foil 12. The negative electrode metal paste 5 is received in the accommodation space formed by enclosing the conductive metal foil 12, the liquid chamber 2 and the positive electrode sheet 3. A separator 6 is provided between the positive electrode sheet 3 and the adjacent liquid chamber 2. One side of the separator 6 is hermetically pressed with the positive electrode sheet 3 through an alkali-resistant material, and the other side of the separator 6 is hermetically pressed with the second side 22 of the liquid chamber 2 through an alkali-resistant material.

[0043] It can be understood that the conductive metal foil 12 is located between the plate body 11 and the liquid chamber 2, and the liquid chamber 2 is located between the conductive metal foil 12 and the positive electrode sheet 3. The three enclose to form an accommodation space, and the negative electrode metal paste 5 adheres to the conductive metal foil 12 and is located in this accommodation space. In this way, the negative electrode metal paste 5 can be set to a certain thickness, such as 80% of the thickness of the liquid chamber 2. In this way, more volume of the negative electrode metal paste 5 can be accommodated, increasing the capacity of the metal-air battery.

[0044] Among them, the conductive metal foil 12 can be a tin-plated copper foil, an indium-plated copper foil, a tin-plated stainless steel foil or an indium-plated stainless steel foil, etc. The negative electrode metal paste 5 can be a zinc paste. The zinc paste contains zinc powder, a high-concentration KOH electrolyte, a gelling agent, and an inhibitor. The metal coating on the conductive metal foil 12 is used to prevent the conductive metal foil 12 from reacting with metal ions in the electrolyte. The separator 6 is a carboxylated non-woven fabric separator with hydrophilicity. Setting the separator 6 between the positive electrode sheet 3 and the liquid chamber 2 can effectively isolate the positive and negative electrodes and at the same time realize the transmission of the electrolyte and air. The conductive metal foil 12 is thermocompression bonded to the plate body 11 through a conductive adhesive, which can reduce the internal resistance loss during the charge and discharge process of the battery and improve the energy efficiency. The high-bonding-strength conductive adhesive can greatly reduce the thickness of the adhesive layer to avoid glue overflow, and has a short curing time, is easy to adapt to continuous production, and is beneficial to the miniaturized design of the battery volume.

[0045] When the materials of the liquid chamber 2 and the bipolar plate 1 meet the requirements for direct welding, for example, both the liquid chamber 2 and the bipolar plate 1 are made of polypropylene-based materials, the covering area of the conductive metal foil 12 can be set to be smaller than the outer frame area of the liquid chamber 2, that is, the outer peripheral edges of the conductive metal foil 12 and the separator 6 are both pressed between the liquid chamber 2 and the conductive metal foil 12, and the first side 21 of the liquid chamber 2 is welded to the bipolar plate 1 in a "return" shaped area.

[0046] When the materials of the liquid chamber 2 and the bipolar plate 1 do not meet the requirements for direct welding, for example, the liquid chamber 2 is made of polypropylene and the bipolar plate 1 is made of graphite, the covering area of the conductive metal foil 12 can be set to be larger than the outer frame area of the liquid chamber 2, and the first side 21 of the liquid chamber 2 is hermetically connected to the conductive metal foil 12 by laser welding.

[0047] Furthermore, the outer peripheral edge of the diaphragm 6 is pressed between the liquid cavity 2 and the positive electrode sheet 3. In this way, the diaphragm 6 can cover the inner frame area of ​​the liquid cavity 2, so that the air distribution is more uniform. It can be understood that the outer peripheral area of ​​the diaphragm 6 is larger than the inner frame area of ​​the liquid cavity 2 and smaller than the outer frame area of ​​the liquid cavity 2, that is, the diaphragm 6 covers a part of the joint surface between the liquid cavity 2 and the positive electrode sheet 3 to ensure that the sealing and pressing area between the liquid cavity 2 and the positive electrode sheet 3 is in a complete "U" shape, so that the diaphragm 6 can be prevented from conducting the electrolyte out of the liquid cavity 2 and electrolyte leakage.

[0048] In the embodiment of the present invention, a gas flow channel 13 is provided on the bipolar plate 1 adjacent to the positive electrode sheet 3 , and the gas flow channel 13 is located on a side of the bipolar plate 1 close to the positive electrode sheet 3 .

[0049] Specifically, Figure 2 As shown, a gas flow channel 13 is provided on the positive side of the bipolar plate 1. The gas flow channel is a groove opened on the bipolar plate 1, and the groove runs through both ends of the bipolar plate 1. A plurality of parallel and spaced gas flow channels 13 are provided on the bipolar plate 1. After the positive electrode sheet 3 and the bipolar plate 1 are hot-pressed and bonded by conductive adhesive, a plurality of parallel airflow channels are formed between the positive electrode sheet 3 and the bipolar plate 1 for air circulation. The gas flow channel can be linear or curved, and this embodiment does not impose any specific restrictions on this.

[0050] In a specific embodiment of the present invention, see Figure 1 , Figure 2 , Figure 4 and Figure 5 The plurality of bipolar plates 1 include a first bipolar plate 1a, a second bipolar plate 1b and a third bipolar plate 1c. At least one third bipolar plate 1c is stacked between the first bipolar plate 1a and the second bipolar plate 1b. Inspection structures are provided on the first bipolar plate 1a and the second bipolar plate 1b, and the inspection structures are used to monitor the status of the metal-air battery, such as temperature, pressure, etc.

[0051] It can be understood that the metal-air battery of this embodiment includes at least three bipolar plates 1 , at least two liquid chambers 2 and at least two positive electrode sheets 3 , and in some embodiments also includes at least two negative electrode metal sheets 4 .

[0052] As a specific embodiment, when the number of the third bipolar plates 1c is one, the numbers of the liquid chambers 2, the positive plates 3 and the negative metal plates 4 are all two. One liquid chamber 2 is disposed between the first bipolar plate 1a and the third bipolar plate 1c, and the other liquid chamber 2 is disposed between the second bipolar plate 1b and the third bipolar plate 1c. A negative metal plate 4 and a positive plate 3 are respectively disposed on two sides of each liquid chamber 2. The first side 21 of each liquid chamber 2 is welded to the joint surface of the bipolar plate 1 adjacent thereto, and a positive plate 3 is provided between the second side 22 of each liquid chamber 2 and the bipolar plate 1 adjacent thereto. One side of each positive plate 3 is thermocompression bonded to the joint surface of the bipolar plate 1 through a conductive adhesive, and the other side is hermetically press-fitted to the joint surface of the second side 22 of the liquid chamber 2 through an alkali-resistant material. Thus, a metal-air battery structure with two batteries connected in series is formed.

[0053] See Figure 1 and Figure 2 , as another specific embodiment, the number of the third bipolar plates 1c is two, and the corresponding numbers of the liquid chambers 2, the positive plates 3 and the negative metal plates 4 are all three. A negative metal plate 4 is provided between the liquid chamber 2 closest to the first bipolar plate 1a and the first bipolar plate 1a, and a positive plate 3 is provided between the liquid chamber 2 closest to the second bipolar plate 1b and the second bipolar plate 1b. A positive plate 3, a third bipolar plate 1c and a negative metal plate 4 are provided between every two adjacent liquid chambers 2. The connection relationships among the bipolar plates 1, the negative metal plates 4, the liquid chambers 2 and the positive plates 3 are as described in the above embodiments, and will not be elaborated herein.

[0054] It should be noted that the negative metal plates 4 in the above-listed embodiments can be replaced with conductive metal foils 12 and negative metal pastes 5, and a separator 6 is provided between adjacent liquid chambers 2 and positive plates 3.

[0055] The embodiment of the present invention further provides a manufacturing method of a metal-air battery. The manufacturing method of the metal-air battery can be applied to the metal-air battery described in any of the above embodiments, and includes the following steps: Step S1, hermetically connecting the first bipolar plate 1a and the first side 21 of a liquid chamber 2 through welding to obtain a first component 100, see Figure 3 and Figure 6 .

[0056] Step S2, thermocompression bonding the second bipolar plate 1b and a positive plate 3 through a conductive adhesive to obtain a second component 200, see Figure 3 and Figure 6 .

[0057] Step S3, thermocompression bonding one side of the third bipolar plate 1c and a positive plate 3 through a conductive adhesive, and hermetically connecting the other side of the third bipolar plate 1c and the first side 21 of a liquid chamber 2 through welding to obtain a third component 300, see Figure 3 andFigure 6 。

[0058] In step S4, the second side 22 of the liquid chamber 2 in the first component 100 is hermetically press-fitted to the positive electrode plate 3 in the third component 300 through an alkali-resistant material, and the second side 22 of the liquid chamber 2 in the third component 300 is hermetically press-fitted to the positive electrode plate 3 in the second component 200 through an alkali-resistant material.

[0059] In step S1, first, the negative electrode side of the first bipolar plate 1a is attached to the first side 21 of a liquid chamber 2, and then the two are welded to form a sealed connection, thereby obtaining the first component 100.

[0060] In step S2, first, the conductive adhesive is applied to the positive electrode side of the second bipolar plate 1b, and then the positive electrode plate 3 is attached thereto and thermally pressed and joined therewith, thereby obtaining the second component 200. For example, hot pressing is performed at 70 °C and cured for 15 minutes.

[0061] Step S3 specifically includes: Step S31, applying the conductive adhesive to the positive electrode side of the third bipolar plate 1c, attaching the positive electrode plate 3 thereto and thermally pressing and joining therewith. For example, hot pressing is performed at 70 °C and cured for 15 minutes. Step S32, the negative electrode side of the third bipolar plate 1c is hermetically connected to the first side 21 of a liquid chamber 2 by welding. Among them, step S31 and step S32 do not have a sequential order.

[0062] Among them, the specific welding process in step S1 and step S32 can be determined according to the materials of the corresponding liquid chamber 2 and bipolar plate 1, such as laser welding or thermoplastic welding, etc. For example, in the case where the bipolar plate 1 is a non-transparent polypropylene-based composite material and the liquid chamber 2 is made of transparent polypropylene material, laser welding or thermoplastic welding can be used. For another example, in the case where both the bipolar plate 1 and the liquid chamber 2 are made of non-transparent polypropylene material, thermoplastic welding can be used.

[0063] Before performing the welding operations in step S1 and step S32, the first side 21 of the liquid chamber 2 is roughened and surface treatment agent is applied to improve the welding effect.

[0064] Step S4 includes: Step S41, hermetically press-fitting the second side 22 of the liquid chamber 2 in the first component 100 to the positive electrode plate 3 in the third component 300 through an alkali-resistant material. Step S42, hermetically press-fitting the second side 22 of the liquid chamber 2 in the third component 300 to the positive electrode plate 3 in the second component 200 through an alkali-resistant material. Among them, step S41 and step S42 do not have a sequential order.

[0065] The above steps S1, S2, and S3 do not have a sequential order, and can be carried out sequentially in a single line, or can be carried out simultaneously in multiple lines. After completing the production of the first component 100, the second component 200, and the third component 300, step S4 is then carried out.

[0066] The traditional metal-air battery structure requires connecting multiple parts in sequence, namely the bipolar plate 1, the liquid chamber 2, and the positive electrode plate 3, layer by layer, resulting in low production efficiency. In the embodiments of the present invention, the metal-air battery structure is divided into three components, namely the first component 100, the second component 200, and the third component 300. The three components can be processed by three independent process steps, namely step S1, step S2, and step S3, respectively, and then the three components are hot-pressed and sealed together with an alkali-resistant material, improving the production efficiency. In actual production, the three components can be inventoried separately, and different capacity specifications of metal-air batteries can be conveniently produced by adjusting the quantity of the third component 300.

[0067] When the metal-air battery further includes a negative metal sheet 4, before the first bipolar plate 1a is hermetically connected to the first side 21 of a liquid chamber 2 by welding in step S1, it further includes: thermocompression bonding the first bipolar plate 1a to a negative metal sheet 4 with a conductive adhesive. Before the other side of the third bipolar plate 1c is hermetically connected to the first side 21 of a liquid chamber 2 by welding in step S3, it further includes: thermocompression bonding the other side of the third bipolar plate 1c to a negative metal sheet 4 with a conductive adhesive.

[0068] Wherein, when the materials of the bipolar plate 1 and the liquid chamber 2 meet the requirements for direct welding, after the negative metal sheet 4 is thermocompression bonded to the bipolar plate 1 with a conductive adhesive, the liquid chamber 2 is directly welded to the bipolar plate 1. When the materials of the bipolar plate 1 and the liquid chamber 2 do not meet the requirements for direct welding, for example, the bipolar plate 1 is made of graphite and the liquid chamber 2 is made of polypropylene, after the negative metal sheet 4 is thermocompression bonded to the bipolar plate 1 with a conductive adhesive, the first side 21 of the liquid chamber 2 is welded to the conductive metal foil 12 in the negative metal sheet 4.

[0069] Step S1 specifically includes: step S11, thermocompression bonding the negative side of the first bipolar plate 1a to a negative metal sheet 4 with a conductive adhesive. Specifically, the conductive adhesive is applied to the negative side of the first bipolar plate 1a, and a negative metal sheet 4 is attached thereto and thermocompression bonded. Step S12, the negative side of the first bipolar plate 1a is attached to the first side 21 of a liquid chamber 2, and then the two are welded to form a sealed connection. After step S11 is completed, step S12 is carried out to obtain the first component 100.

[0070] Before the other side of the third bipolar plate 1c is hermetically welded and connected to the first side 21 of a liquid chamber 2 as described in step S3, it specifically includes: Step S31, applying conductive adhesive on the positive electrode side of the third bipolar plate 1c, attaching the positive electrode sheet 3 thereto, and performing thermocompression bonding therewith. Step S33, applying conductive adhesive on the negative electrode side of the third bipolar plate 1c, attaching the negative metal sheet 4 thereto, and performing thermocompression bonding therewith. Step S31 and step S33 are not in a specific order. After completing step S31 and step S33, a three-in-one structure of the bipolar plate 1, the positive electrode sheet 3, and the negative metal sheet 4 is formed, and then step S32 is performed to hermetically weld and connect the three-in-one structure to the liquid chamber 2.

[0071] It should be noted that when the negative metal sheet 4 in the above embodiment is replaced with a conductive metal foil 12 and a negative metal paste 5, and a separator 6 is provided between the adjacent liquid chamber 2 and the positive electrode sheet 3, the specific steps of the above steps S1, S2, and S3 need to be adjusted accordingly. Before the first bipolar plate 1a is hermetically welded and connected to the first side 21 of a liquid chamber 2 as described in step S1, it further includes: thermocompression bonding a plate body 11 and a conductive metal foil 12 through conductive adhesive to obtain the first bipolar plate 1a; coating the negative metal paste 5 on the conductive metal foil 12 of the first bipolar plate 1a. Step S2 specifically includes: thermocompression bonding the second bipolar plate 1b and a positive electrode sheet 3 through conductive adhesive, and hermetically pressing and bonding the side of the positive electrode sheet 3 away from the second bipolar plate 1b to a separator 6 through an alkali-resistant material to obtain the second assembly 200. Before the side of the third bipolar plate 1c is thermocompression bonded to a positive electrode sheet 3 as described in step S3, it further includes: thermocompression bonding a plate body 11 and a conductive metal foil 12 through conductive adhesive to obtain the third bipolar plate 1c; coating the negative metal paste 5 on the conductive metal foil 12 of the third bipolar plate 1c.

[0072] Based on the above embodiments, the method for manufacturing a metal-air battery provided by the present invention further includes: manufacturing a plurality of third assemblies 300, and stacking and arranging a plurality of third assemblies 300 between the first assembly 100 and the second assembly 200, and hermetically pressing and bonding each adjacent two third assemblies 300 through an alkali-resistant material.

[0073] Specifically, step S3 is repeatedly executed multiple times to obtain a plurality of third assemblies 300. When the number of the third assemblies 300 is two, refer to Figure 1 and Figure 2, a metal-air battery structure with three batteries connected in series can be obtained. When the number of the third components 300 is three, a metal-air battery structure with three batteries connected in series can be obtained. And so on, different numbers of the third components 300 are selected according to different battery capacities. The first component 100, the third component 300, and the second component 200 are sequentially sealed and pressed through an alkali-resistant material, or the second component 200, the third component 300, and the first component 100 are sequentially sealed and pressed through an alkali-resistant material.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A metal-air battery, characterized in that: include: A plurality of bipolar plates, wherein the plurality of bipolar plates are stacked in sequence; A liquid cavity, wherein the liquid cavity is provided between each two adjacent bipolar plates, the liquid cavity having a first side and a second side facing the two adjacent bipolar plates respectively, the first side being sealed and connected to the bipolar plate adjacent thereto by welding; A positive electrode sheet is provided between the second side and the bipolar plate adjacent thereto, one side of the positive electrode sheet is hot-pressedly bonded to the bipolar plate by conductive adhesive, and the other side of the positive electrode sheet is sealed and pressed with the second side by alkali-resistant material.

2. The metal-air battery according to claim 1, characterized in that: Also includes: A negative electrode metal sheet is provided between the first side and the bipolar plate adjacent thereto, and the negative electrode metal sheet is hot-pressed and bonded to the bipolar plate by conductive adhesive.

3. The metal-air battery according to claim 2, characterized in that: The outer periphery of the negative electrode metal sheet is pressed between the liquid chamber and the bipolar plate.

4. The metal-air battery according to claim 1, characterized in that: The bipolar plate for welding with the liquid cavity comprises: a plate body and a conductive metal foil, the conductive metal foil and the plate body are hot-pressed and bonded by the conductive adhesive, the conductive metal foil is coated with a negative electrode metal paste, and the negative electrode metal paste is contained in a containing space formed by the conductive metal foil, the liquid cavity and the positive electrode sheet; A diaphragm is provided between the positive electrode sheet and the liquid cavity adjacent thereto, one side of the diaphragm is sealed and pressed with the positive electrode sheet via an alkali-resistant material, and the other side of the diaphragm is sealed and pressed with the second side via an alkali-resistant material.

5. The metal-air battery according to claim 1, characterized in that: The alkali-resistant material is hot melt adhesive, alkali-resistant adhesive or carbon fiber plate.

6. The metal-air battery according to claim 1, characterized in that: A gas flow channel is provided on the bipolar plate adjacent to the positive electrode sheet, and the gas flow channel is located on a side of the bipolar plate close to the positive electrode sheet.

7. The metal-air battery according to any one of claims 1 to 6, characterized in that: The plurality of bipolar plates include: a first bipolar plate, a second bipolar plate and a third bipolar plate, at least one of the third bipolar plates is stacked between the first bipolar plate and the second bipolar plate, and the first bipolar plate and the second bipolar plate are provided with inspection structures.

8. A method for manufacturing a metal-air battery, characterized in that: Includes steps: Sealing and connecting the first bipolar plate to the first side of a liquid chamber by welding to obtain a first assembly; The second bipolar plate is thermally pressed and bonded to a positive electrode sheet by means of a conductive adhesive to obtain a second assembly; Hot-pressing one side of the third bipolar plate to a positive electrode sheet by conductive adhesive, and sealingly connecting the other side of the third bipolar plate to a first side of a liquid chamber by welding to obtain a third assembly; The second side of the liquid cavity in the first component and the positive electrode sheet in the third component are sealed and pressed together through alkali-resistant material, and the second side of the liquid cavity in the third component and the positive electrode sheet in the second component are sealed and pressed together through alkali-resistant material.

9. The method for manufacturing a metal-air battery according to claim 8, characterized in that: Before the first bipolar plate is sealed and connected to the first side of a liquid chamber by welding, the method further includes: hot-pressing and bonding the first bipolar plate to a negative electrode metal sheet by conductive adhesive; Before the other side of the third bipolar plate is sealed and connected to the first side of a liquid chamber by welding, the method further includes: hot-pressing and bonding the other side of the third bipolar plate to a negative electrode metal sheet by using the conductive adhesive.

10. The method for manufacturing a metal-air battery according to claim 8 or 9, characterized in that: A plurality of the third components are manufactured and stacked between the first component and the second component, and each adjacent two third components are sealed and pressed together by an alkali-resistant material.

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