Composite grid, pole plate, manufacturing method of pole plate and storage battery using pole plate

Abstract

The invention discloses a composite grid, a pole plate, a manufacturing method of the pole plate and a storage battery using the pole plate, and relates to a lead-acid storage battery. The plastic-lead composite grid solves the problems that the existing plastic-lead composite grid exists or occupies more space of active substances, or ribs in a frame are insufficiently protected, and the ribs of the grid are easy to damage during lead plaster coating. The invention designs a composite grid which is characterized in that a grid body (2) is fixed on a single surface of a foldable acid-resistant porous base material (1) which is not smaller than the grid body (2), and the tensile strength of the base material (1) is greater than that of the grid body (2). After the grid body (2) is coated with lead plaster, the part, larger than the designed area of the pole plate, of the base material (1) is folded to the lead plaster coating (3) and pressed to form the pole plate. The manufacturing method of the polar plate comprises the following steps: 1, manufacturing the composite grid; step 2, coating lead paste; and 3, manufacturing a polar plate. The storage battery comprises the polar plate. The method is suitable for manufacturing bag type laminated lead-acid storage batteries, bag type wound lead-acid storage batteries, bag type folded lead-acid storage batteries, bag type lead-carbon lead-acid storage batteries and the like.

Description

Technical Field

[0001] This invention relates to the field of lead-acid batteries, specifically to a composite grid, an electrode plate containing the composite grid, a method for manufacturing the electrode plate, and a battery using the electrode plate. Background Technology

[0002] The lead material used in making lead-acid battery grids is relatively heavy, which greatly reduces the specific energy of lead-acid batteries. Lightweighting the grids is an important research direction for improving the specific energy of lead-acid batteries. Battery manufacturers and researchers at relevant research institutes have long designed numerous beneficial technical solutions to reduce the amount of lead used in the grids without compromising strength and performance. One such technical approach is to make some of the frame and ribs from acid-resistant plastic materials.

[0003] For example, announcement number CN109742407A, entitled "A Composite Grid for Lead-Acid Batteries," discloses that the upper frame ribs, vertical ribs, and horizontal ribs are made of lead alloy, while the lower frame ribs and side frame ribs are made of polymer. Therefore, compared to grids made entirely of lead alloy, the total lead consumption is reduced, the battery production cost is lowered, and the performance of the lead-acid battery is not affected. This also improves the gravimetric energy density of the lead-acid battery.

[0004] The patent, published under CN207883813U, is titled "An Ultra-Thin Composite Grid for Power Batteries," and includes a frame and reinforcing ribs. The frame comprises a conductive inner frame and an insulating outer frame fitted over the conductive inner frame. The thickness of the insulating outer frame is greater than that of the conductive inner frame. The reinforcing ribs are connected to the conductive inner frame. This solution utilizes a composite structure of an insulating outer frame and a conductive inner frame for the power battery grid, which effectively reduces the grid thickness of the conductive portion and improves the specific capacity of the battery.

[0005] Utility model patent CN204991849U discloses a composite grid, comprising a conductive grid and a paste carrier grid. The conductive grid has a fork-shaped structure, including lugs, busbars, and conductive strips. The paste carrier grid has a rectangular grid structure, including four fixed frames, horizontal grids, mounting grooves, and reinforcing ribs. The conductive grid and the paste carrier grid are connected together by injection molding, insertion, or embedded composite bonding. This significantly reduces the overall weight of the grid.

[0006] The aforementioned patented technology, through structural innovation, introduces non-conductive materials as the frame and ribs to support the active material. While maintaining grid strength, this allows the amount of active material coated on the plates to exceed the height of the conductive grid, reducing lead consumption and thus increasing the battery's specific energy. Furthermore, compared to composite grids made of light metals and lead, it offers advantages such as stability, reliability, and lighter weight in acidic environments.

[0007] However, the shortcomings of the aforementioned patent are as follows: the non-conductive ribs, such as the paste-carrying grid or other structures that protect and replace the conductive ribs within the frame, occupy the space of the active material. Furthermore, this non-conductive material, located within the active material, affects the electrochemical reactions between the grid and this portion of the active material, as well as the electrochemical reactions and lead ion migration within the active material itself. If the non-conductive ribs within the frame are reduced as a result, and the grid is made lighter and the amount of lead used in the grid is reduced, the conductive ribs lack sufficient tensile strength, making them prone to damage, at least during lead paste application. Summary of the Invention

[0008] The purpose of this invention is to address the problems of existing grids: they occupy too much space for active material, affecting the electrochemical reaction of the plates, or they provide insufficient protection for the inner ribs of the frame, making the grid ribs easily damaged during lead paste application. Therefore, this invention provides a composite grid, plates, a method for manufacturing the plates, and a battery using these plates.

[0009] The technical solution of this invention is:

[0010] A composite grid includes a substrate and a grid body, the grid body being fixed to one side of the substrate, the grid body having at least one tab, the substrate being a foldable acid-resistant porous substrate, and the tensile strength of the substrate being greater than the tensile strength of the grid body.

[0011] This invention specifies that the grid body is fixed on one side of a foldable, acid-resistant porous substrate, rather than both sides. This is significant because it allows for the selection of composite grid substrates with insulating properties, enabling the fabrication of bag-type electrode plates. It can even replace separators, provided the density of the selected composite grid substrate is comparable to that of the separator and its liquid storage capacity meets the requirements of the electrode plate. In other words, acid-resistant, foldable separator materials with tensile strength greater than that of the grid body 2 are also suitable as substrates for composite grids.

[0012] Alternatively, a low-density substrate can be selected as needed, and higher porosity can result in better ion migration performance.

[0013] Furthermore, one side of the grid body is bonded and fixed to one side of the substrate using an acid-resistant adhesive.

[0014] Preferably, the grid body is sewn and fixed to one side of the substrate 1 by acid-resistant sewing thread segments.

[0015] Preferably, the number of vertical ribs in the grid body is greater than the number of horizontal ribs. Alternatively, the horizontal ribs can be completely removed.

[0016] Furthermore, the grid body is sewn and fixed to one side of the substrate by acid-resistant sewing thread segments.

[0017] Furthermore, the substrate is provided with a tab avoidance structure.

[0018] The present invention also provides an electrode plate employing a composite grid, comprising a composite grid and a lead paste coating, wherein the substrate in the composite grid is larger than the designed area of ​​the electrode plate, and the other side of the grid body is coated with the lead paste coating; the composite grid, which is larger than the designed area of ​​the electrode plate, is folded onto the lead paste coating from at least one point, at least one edge of the electrode plate is closed by the composite grid, and one side of the substrate in the composite grid is entirely on the outermost layer of the electrode plate.

[0019] Furthermore, a composite grid larger than the electrode plate encloses and seals the electrode plate into a bag-type electrode plate. This invention is suitable for manufacturing bag-type stacked electrode plates, bag-type wound electrode plates, bag-type folded electrode plates, and bag-type high-carbon electrode plates.

[0020] Preferably, the folded composite grating substrate is glued and fixed onto the overlapping substrate.

[0021] The present invention also provides a method for manufacturing an electrode plate, which includes the following steps:

[0022] Step 1: Preliminary fabrication of composite grating;

[0023] A composite grid is formed by fixing the grid body on a single side of a substrate with an area larger than the designed area of ​​the electrode plate.

[0024] Step 2: Apply lead paste coating;

[0025] Apply lead paste coating to the grid body fixed on the substrate;

[0026] Step 3: Fabricating the electrode plates;

[0027] Fold the portion of the composite grid that is larger than the designed area of ​​the electrode plate onto the lead paste coating, and press the composite grid and the lead paste coating together before the lead paste coating solidifies.

[0028] Furthermore, step three also includes sealing the electrode plates before pressing. Because the electrode plates are folded, wrapped, and glued shut by the composite grid substrate, the lead paste will not be squeezed out during pressing. The lead paste moves from high-density areas to low-density areas, achieving a uniform density across all parts. Alternatively, the overlapping parts of the substrate may not be glued; instead, the electrode plates may be completely covered, and the stability of the folded edges may be maintained by winding or folding. This can be considered as an implementation option.

[0029] The present invention also provides a storage battery comprising the aforementioned plates.

[0030] Preferably, the area of ​​the grid body is less than or equal to the area of ​​the substrate.

[0031] In addition, as needed, the present invention can use various pure lead grids, expanded metal grids and other frameless grids, ultra-thin grids, curved grids, grids with fewer or no horizontal ribs, and grids with uniform current distribution, and fix them on a foldable acid-resistant porous substrate to be used as composite grids.

[0032] The foldable, acid-resistant, porous substrate used in this invention can be: chemical fiber cloth, glass fiber cloth, non-woven fabric, and also includes polymer plastic film and other materials, or existing partition materials. As long as it is foldable, acid-resistant, porous, and has a tensile strength greater than that of the plate grid it is combined with, it is within the scope of application of this invention.

[0033] Among them, composite grids using chemical fiber cloth as the substrate are characterized by high strength. Composite grids using glass fiber cloth as the substrate have the advantage of high temperature resistance. Composite grids using acid-resistant porous polymer plastic film as the substrate and composite grids using chemical fiber non-woven fabric as the substrate have the processing advantage of being able to be thermally melt-bonded.

[0034] The plate grid body of the present invention can be bonded and fixed to one side of the substrate using a variety of acid-resistant adhesives, such as hot melt adhesive, epoxy resin, conductive adhesive, self-adhesive sticker, and other colloids suitable for acidic environments.

[0035] In this invention, one side of the grid is completely coated with adhesive and fully bonded to the substrate, thus protecting all the grid ribs. Alternatively, a portion of the grid may be coated with adhesive but not bonded to the substrate. The purpose of the adhesive is to slow down the corrosion rate of the grid in acidic environments, preventing rib breakage in the later stages of battery use, thereby extending the battery's lifespan. Curved grid panels can be used, with the portion close to the substrate bonded and fixed to it. Alternatively, a two-stage adhesive application can be used: the first application forms a protective layer on one or a large area of ​​a single rib, and the second application fixes it to the substrate only in selected areas. All ribs can also be coated with adhesive, but the adhesive width is less than the rib width.

[0036] The present invention can also use acid-resistant thread segments to sew and fix the grid body to one side of the substrate, and further use conductive acid-resistant thread segments to sew and fix the grid body to one side of the substrate. Even further, one side of the grid body uses conductive acid-resistant thread segments, and the other side of the substrate uses non-conductive acid-resistant thread segments to sew and fix the grid body to one side of the substrate.

[0037] Acid-resistant conductive wire segments can be made of carbon fiber, lead-plated metal wire that meets sewing strength requirements, lead-plated polymer wire, fiberglass with a lead material layer on the surface, or wire segments that are hinged together with lead wire and acid-resistant high-strength wire segments.

[0038] The present invention also provides an electrode plate comprising a composite grid and a lead paste coating applied to the composite grid, wherein at least one of the substrates of the composite grid is larger than the designed area of ​​the electrode plate, the composite grid larger than the designed area of ​​the electrode plate is folded onto the lead paste coating from at least one point, at least one edge of the electrode plate is closed by the composite grid, and one side of the composite grid substrate is entirely on the outermost layer of the electrode plate.

[0039] In this invention, after coating one side of the composite grid body with lead paste, the portion of the composite grid larger than the designed electrode area is folded onto the lead paste coating from one, two, three, or four sides of the electrode, avoiding the tabs. This ensures that at least one side of the electrode is enclosed by the composite grid, and the upper layer of lead paste on the electrode is also partially or completely sealed by the composite grid. Folding and sealing the lower edge of the electrode prevents lead paste from falling into the electrolyte from below. Sealing both sides of the electrode protects the lead paste on both sides, especially when using mesh grids or other frameless grids, significantly reducing lead paste loosening and shedding. When three or four sides and the electrode are completely sealed, a bag-type electrode is directly formed, which not only more effectively prevents the active material from loosening and shedding but also allows for the filling of more lead paste.

[0040] Increasing the number of folded electrode edges and the area of ​​electrode enclosure does not increase costs far below the benefits of improved electrode and battery performance. It offers exceptional cost-effectiveness. Furthermore, it allows for greater technical flexibility in product manufacturing to meet the diverse needs of different consumer groups, catering to various situations and requirements.

[0041] In many cases, the area of ​​the grid body fixed on a foldable, acid-resistant porous substrate is larger than the designed area of ​​the electrode plate. In some cases, the area of ​​the grid body is not less than the area of ​​the lead paste coating; in other cases, the area of ​​the lead paste coating is larger than the area of ​​the grid body, but the difference is limited to the conductive range of the grid ribs. This does not affect the charging and discharging conduction of this portion of the lead paste coating by adjacent ribs.

[0042] The electrode plates produced by this invention can be widely used in starting batteries, start-stop batteries, power batteries, lead-carbon batteries, as well as large and giant batteries for energy storage and marine applications.

[0043] Compared with the prior art, the present invention has the following advantages:

[0044] 1. In the composite grid of the present invention, the non-conductive substrate 1 is located on the outer layer of the electrode plate and will not have an adverse effect or hinder the electrochemical reaction between the active material and the conductive ribs in the electrode plate, or between the active material itself.

[0045] 2. In this invention, the substrate 1 increases the strength of all parts of the fixed grid body 2. The grid frame can use the same amount of lead as the ribs, or the frame can be removed, reducing the amount of lead used in the grid. This solves the technical problems of easy shedding of active material in mesh-type grids and other frameless grids, and easy damage to the ribs of thin pure lead grids.

[0046] 3. The present invention can use a composite grid made of a substrate 1 with the same density as the partition and a grid body 2, which can also be used as a partition, thereby reducing production costs.

[0047] 4. During the coating of lead paste, the tensile and torsional stresses experienced by the composite grid of the present invention are largely borne by the substrate 1 of the composite grid. Its superior resistance to torsion and tension compared to the grid body 2 protects the grid body 2. Especially in the fabrication of wound electrodes, it effectively prevents electrode torsion and deformation during winding, as well as electrode breakage.

[0048] 5. The foldable acid-resistant porous substrate 1 in the composite grid of the present invention occupies less space than the non-conductive frame and ribs of the existing composite grid. It can be coated with more lead paste under the same specifications, which reduces the lead consumption of the grid and improves the specific energy of the battery.

[0049] 6. The present invention fixes the plate grid body 2 to the folded edge of the substrate 1, which can improve the strength of the easily damaged parts on the side of the bag-type electrode plate and the stability of the folded part.

[0050] 7. In this invention, the substrate 1 is transformed into part of the electrode plate by fixing the grid body 2 to one side of it. Instead of the foldable acid-resistant porous substrate 1 wrapping the outer layer of the electrode plate, it is a combination of the foldable acid-resistant porous substrate 1 and the grid body 2, i.e., a composite grid wrapping the outer layer of the electrode plate. This allows the substrate 1 to be more tightly bonded to the lead paste 3 through the fixed grid body 2, increasing the overall strength of the electrode plate.

[0051] 8. The grid body 2 of this invention is mainly composed of vertical ribs, which can reduce or eliminate horizontal ribs. The substrate 1 of the composite grid replaces the horizontal ribs to stabilize the vertical ribs and stabilize the lead paste. This allows for the use of less lead in the grid to create more vertical ribs, and more vertical ribs are more conducive to a more balanced distribution of current on the upper and lower plates. Attached Figure Description

[0052] Figure 1 This is a schematic diagram of a composite grid that can be folded into a bag-shaped electrode plate.

[0053] Figure 2 This is a schematic diagram of the composite grid of the multi-pole wound or folded battery of the present invention, which has been coated with lead paste.

[0054] Figure 3 This is a schematic diagram of a composite grid of a stacked battery with a folded edge.

[0055] Figure 4 This is a schematic diagram of a composite plate grid with uniform current distribution, mainly composed of vertical ribs.

[0056] Figure 5 This is a schematic diagram of a laminated composite grid, including grating ribs and lead paste coating in the folded part.

[0057] Figure 6 This is a schematic diagram of a composite grid with lead paste applied to a narrow-edged, wound or folded battery.

[0058] Among them: 1. Substrate, 11. Folded part, 12. Overlapping part of substrate 1 after folding, 13. Avoidance notch at the corresponding tab of the substrate, 14. Folding point, 15. Second folding part, 2. Grid body, 21. Tab, 3. Lead paste coating. Detailed Implementation

[0059] Specific implementation method one: Combining Figure 1 This embodiment describes a process where, after coating the composite grid body 2 with lead paste coating 3, the folded portions 11 on the left and right sides, which are larger than the designed area of ​​the electrode plate, are folded towards the center and covered with the lead paste coating 3. Further, the overlapping portions 12 of the folded substrate 1 are glued together. Then, the upper and lower folded portions 11 are folded and glued to the substrate 1 of the left and right folded portions, forming a completely sealed bag-type electrode plate. Epoxy resin adhesive, hot melt adhesive, or self-adhesive stickers can be used for the adhesive application.

[0060] In this embodiment, the tab avoidance structure is a notch 13 of the base material 1 corresponding to the tab 21. The base material at the notch can be cut off or cut open and then bonded to the tab 21 as a whole, especially when the tab 21 needs to be strengthened.

[0061] The specific implementation includes the following steps:

[0062] Step 1: Preliminary fabrication of composite grating;

[0063] The plate grid body 2 is fixed on one side of the substrate 1 with an area larger than the designed area of ​​the electrode plate to form a composite plate grid.

[0064] Step 2: Apply lead paste coating 3;

[0065] A lead paste coating 3 is applied to the grid body 2 fixed on the substrate 1;

[0066] Step 3: Fabricating the electrode plates;

[0067] Fold the portion of the composite grid that is larger than the designed area of ​​the electrode plate onto the lead paste coating 3, seal it into a bag-type electrode plate, and press the composite grid and the lead paste coating 3 together before the lead paste coating 3 solidifies.

[0068] Specific Implementation Method Two: Combining Figure 2 In this embodiment, the lower foldable portion of the composite grid is folded upward from folding point 14, and its substrate 1 overlaps with the substrate 1 of the upper part and both ends that do not have grids and lead paste. The overlapping parts are further glued together, and a bag-type electrode plate can be formed by folding only once.

[0069] The lower part of the tab 21 is glued and fixed to the middle of the overlapping upper and lower layers of the foldable acid-resistant porous substrate 1. This is suitable for use when manufacturing high-tab electrode plates. It is particularly suitable for high-tab electrode plates that are wound or folded, because after winding or folding, the battery case width is not increased as with stacked electrode plates. However, when the electrode plate is sealed, at least the current transmission connection between the tab 21 and the outside of the electrode plate must not be sealed. Other components, connections, and implementation steps are the same as in Specific Embodiment 1.

[0070] Specific implementation method three: Combining Figure 3 This implementation method is described below. Figure 3 This is one of the most widely used implementation methods of stacked electrode plates. The grid body 2 is fixed on the substrate 1. The part of it that is larger than the electrode plate is folded upward from the bottom at the folding point 14. In the overlapping part, the grid rib density is less than that of other parts, and less lead paste is applied to other parts, so that the rib distribution of the folded part is as balanced as possible with other parts of the electrode plate.

[0071] The design area of ​​the grid and lead paste coating is further increased, and the lead paste coating on the upper and lower parts of the electrode grid is more evenly distributed.

[0072] Furthermore, the ribs are staggered after folding, so that the grids of each part of the folded electrode are evenly distributed, thereby obtaining a uniform current distribution in each part of the electrode during charging and discharging.

[0073] In this embodiment, the substrate 1 below the folding point fixes the grid body 2. Utilizing the property that lead does not spring back after folding, the shape of the electrode plate at the folded part can be kept relatively stable, eliminating the need for separate fixing of the folded part. In the figure, the composite grid is folded at only one place, closing only one edge, which is one of the simpler embodiments of the present invention. The implementation steps are the same as in Embodiment 1.

[0074] Specific implementation method four: Combination Figure 4In this embodiment, the number of vertical ribs in the grid body 2 is greater than the number of horizontal ribs. This arrangement, as a preferred solution, allows the composite grid substrate 1 to replace the horizontal ribs in stabilizing the vertical ribs and lead paste. This allows more lead used in grid fabrication to be used for the vertical ribs, and more vertical ribs are more conducive to a more balanced current distribution on the electrode plates. The folded edge in the figure is stabilized through the folding at the secondary folding section 15 and adhesive bonding. The implementation steps are the same as in Embodiment 1.

[0075] Specific Implementation Method Five: Combining Figure 5 This embodiment describes an example where both the grid body 2 and the lead paste coating 3 are larger than the designed area of ​​the electrode plate. Its grid rib density is lower than that of other embodiments, and the thickness of the lead paste coating 3 is lower than that of other embodiments.

[0076] After applying lead paste coating 3 to the grid body 2, the portion 11 on the left side that is larger than the designed area of ​​the electrode plate is folded towards the middle, and then the portion 11 on the right side that is larger than the designed area of ​​the electrode plate is folded towards the middle. The overlapping portions of these portions on the substrate 1 are then glued together. After the upper and lower folded portions 11 of the composite grid that are larger than the designed area of ​​the electrode plate are folded, they are glued together with the overlapping portions of the folded substrate 1 on the left and right sides to form a stacked bag-type electrode plate. The paste application steps for the electrode plate are the same as in Embodiment 1.

[0077] Specific Implementation Method Six: Combination Figure 6 This embodiment describes a method for winding or folding an electrode plate. The grid lug 21 first passes through the notch in the substrate 1, and then the grid body 2 is glued and fixed to the substrate 1. The four sides of the folded portion 11, which is larger than the designed area of ​​the electrode plate, are folded onto the lead paste coating 3. The folded edges are narrow and do not form a pocket-shaped electrode plate. The overlapping parts of the folded substrate 1 are glued together, forming protection for the four sides of the electrode plate. The paste application steps for the electrode plate are the same as in Embodiment 1.

[0078] Specific Implementation Method Seven: The grid panels produced on the production line are directly bonded and fixed to the substrate 1 using hot melt adhesive, quick-drying adhesive, or self-adhesive stickers, which can meet the production line's requirement for rapid adhesive curing. Utilizing the heat generated during grid panel production with hot melt adhesive can reduce production costs. Alternatively, multiple sets of sewing machines can be used in parallel to simultaneously sew and fix the grid panels to the substrate 1, thus protecting the grid panels immediately. Furthermore, the produced composite grid panels are directly coated with lead paste, and even further, directly folded and flattened into electrode plates of the designed specifications. The specific implementation steps are the same as in Implementation Method One.

[0079] In implementing this invention, when folding the portion of the composite grid larger than the electrode design area onto the lead paste coating 3, the following convenient methods can be used as needed:

[0080] 1. The grid is made based on the specifications of the electrode plate. After the grid is fixed on the substrate 1 and lead paste is applied, the part of the substrate 1 that is larger than the grid is folded with the edge of the grid as the folding point.

[0081] 2. The mold frame is made based on the design specifications of the electrode plate. The composite plate grid completes the production processes such as filling lead paste, folding, sealing and pressing within the mold frame, which can more easily produce standard and consistent electrode plates.

[0082] 3. Cut base material 1 into an easily foldable shape, as per the instruction manual. Figure 1 , 5 As shown in Figures 6 and 7, this is used as the folding point.

[0083] In this invention, the composite grid is folded onto the lead paste coating 3, and the substrate 1 is fixed to the overlapping substrate 1 using adhesive. Alternatively, the lead material in the folded grid can be easily folded and does not spring back after folding, allowing the folded portion of the composite grid to achieve a relatively stable state. It is then installed into the battery box in this stable state. The required level of stability can be achieved by adjusting the amount and geometry of lead used in the folded portion, thereby reducing the steps required to fix the folded part of the composite grid.

[0084] When the composite grid is used to manufacture a wound folded electrode plate, the pressing effect of the composite grid on the part of the electrode plate that is wound and folded during the winding and folding process can be used to replace the fixing of the substrate 1 and other parts of the composite grid to the other side of the electrode plate. The folded part of the composite grid can also be kept relatively stable.

[0085] The technical solution of this invention can be widely used in batteries with pouch-type plates such as flat laminated, wound, folded, and lead-carbon plates. Especially for integrated plates used in wound and folded batteries, it reduces the number of plate sides and the manufacturing costs associated with plate segmentation and edge processing compared to laminated plates. This is something that conventional composite grid plastic frames and ribs can hardly achieve.

[0086] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A composite grating, characterized in that: It includes a substrate (1) and a grid body (2), the grid body (2) is fixed on one side of the substrate (1), the grid body (2) has at least one tab (21), the substrate (1) is a foldable acid-resistant porous substrate, and the tensile strength of the substrate (1) is greater than the tensile strength of the grid body (2).

2. The composite grid according to claim 1, characterized in that: One side of the grid body (2) is bonded to one side of the substrate (1) by an acid-resistant adhesive.

3. A composite grid according to claim 1, characterized in that: The grating body (2) is sewn and fixed to one side of the substrate (1) by acid-resistant sewing thread segments.

4. A composite grid according to claim 1, characterized in that: The substrate (1) has a tab (21) clearance structure.

5. A electrode plate employing the composite grid as described in claim 1, characterized in that: It includes a composite grid and a lead paste coating (3), wherein the substrate (1) in the composite grid is larger than the designed area of ​​the electrode plate. Among them, the other side of the grid body (2) is coated with lead paste coating (3); the composite grid larger than the designed area of ​​the electrode plate is folded onto the lead paste coating (3) from at least one place, at least one side of the electrode plate is closed by the composite grid, and one side of the substrate (1) in the composite grid is entirely on the outermost layer of the electrode plate.

6. An electrode plate according to claim 5, characterized in that: A composite grid larger than the electrode plate encloses and seals the electrode plate into a bag-like electrode plate.

7. An electrode plate according to claim 5, characterized in that: The composite grating folded substrate (1) is pasted and fixed onto the overlapping substrate (1).

8. A method for manufacturing the electrode plate according to claim 5, characterized in that: It includes the following steps: Step 1: Preliminary fabrication of composite grating; Select a substrate (1) with an area larger than the designed area of ​​the electrode plate to fix the grid body (2) to form a composite grid; Step 2: Apply lead paste coating (3); Apply lead paste coating (3) to the grid body (2) fixed on the substrate (1); Step 3: Fabricate the electrode plates; Fold the portion of the composite grid that is larger than the designed area of ​​the electrode plate onto the lead paste coating (3), and press the composite grid and the lead paste coating (3) together before the lead paste coating (3) solidifies.

9. The method for manufacturing an electrode plate according to claim 8, characterized in that: Step three also includes sealing the electrode plates before pressing.

10. A storage battery, characterized in that: It includes the electrode plate as described in any one of claims 5-9.

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