Energy storage battery and battery cell

Abstract

The utility model provides an energy storage battery and a battery cell, a positive plate comprises a first positive plate and a second positive plate which are arranged in parallel, a middle positive active material layer can also be arranged between the first positive plate and the second positive plate, and the middle positive active material layer contains positive active conductive particles which are partially or completely fixed in a non-adhesive manner and are in a stacked state. The first positive plate and the second positive plate are respectively provided with a positive current collector, and two sides of the positive current collector are respectively coated with a positive material active layer. The negative plate is provided with a negative current collector, and two layers of the negative current collector are respectively coated with a negative active material layer. And the first positive current collector, the second positive current collector and the negative current collector are metal wire meshes. The electrode plates of the energy storage battery and the battery cell have relatively large length, width and thickness, the electrode material layer is not easy to fall off under the condition that the electrode plates are large and relatively thick, and the energy storage battery and the battery cell are suitable for large-capacity energy storage application scenes and have very high safety and reliability.

Description

Technical Field

[0001] The utility model relates to the field of lithium batteries, and in particular to an energy storage battery and a battery core. Background Art

[0002] Energy storage is an important supporting technology for the large-scale development of new energy, and new energy + energy storage will be an important technology and industry direction for the next decade. Lithium-ion batteries are new high-energy batteries that use lithium-embedded compounds as positive and negative electrode materials. Currently, electrochemical energy storage using lithium-ion batteries as carriers is one of the most widely used forms of energy storage. In recent years, the capacity of lithium-ion batteries used for energy storage has become larger and larger. In the scenario of capacity-type long-term energy storage, the charging and discharging time is relatively long, and energy storage lithium batteries can be charged and discharged at a lower rate, which is suitable for the application of thick electrode batteries. The low-cost preparation of thick electrode large-capacity energy storage lithium batteries has become the development direction of long-term energy storage lithium batteries. However, at present, there are still many problems with the use of thick electrode design, such as the separation of electrode materials and current collectors, and the penetration of electrolytes. Utility Model Content

[0003] In view of the above problems, the utility model provides an energy storage battery and a battery cell. In the battery cell of the energy storage battery, the positive electrode sheet includes a first positive electrode sheet and a second positive electrode sheet arranged in parallel, and an intermediate positive electrode active material layer can also be arranged between the first positive electrode sheet and the second positive electrode sheet, and the intermediate positive electrode active material layer contains part or all of the non-bonded and fixed stacked positive active conductive particles. The first positive electrode sheet and the second positive electrode sheet are both provided with a positive electrode current collector, and the positive electrode material active layer is coated on both sides of the positive electrode current collector. The negative electrode sheet is provided with a negative electrode current collector, and the negative electrode active material layer is coated on both sides of the negative electrode current collector. The first positive electrode current collector, the second positive electrode current collector and the negative electrode current collector are metal wire meshes. The electrode sheet of the energy storage battery cell has a large length and width and a thick thickness. In the case of a large electrode sheet and a thick electrode sheet, the electrode material layer is not easy to fall off, which is suitable for large-capacity energy storage application scenarios and has very high safety and reliability.

[0004] The technical solution provided by the utility model is as follows:

[0005] According to the utility model, a battery cell of an energy storage battery is provided, which is composed of a positive electrode sheet and a negative electrode sheet cross-stacked, and an isolation layer is arranged between the positive electrode sheet and the negative electrode sheet. The length of the positive electrode sheet is about 200-1200 mm, the width is about 100-500 mm, and the thickness is about 0.4-3.5 mm. The positive electrode sheet includes a first positive electrode sheet and a second positive electrode sheet. The first positive electrode sheet includes a first positive electrode collector, a first inner positive electrode active material layer and a first outer positive electrode active material layer covering both sides of the first positive electrode collector, and a first positive electrode ear connected to or integrally formed with the first positive electrode collector. The second positive electrode sheet includes a second positive electrode collector, a second inner positive electrode active material layer and a second outer positive electrode active layer covering both sides of the second positive electrode collector, and a second positive electrode ear connected to or integrally formed with the second positive electrode collector. The first positive electrode sheet and the second positive electrode sheet are arranged side by side to form positive electrode sheets in a manner that the first inner positive electrode active material layer and the second inner positive electrode active material layer are arranged opposite to each other. The length of the negative electrode sheet is about 200-1200 mm, the width is about 100-500 mm, and the thickness is about 0.2-1.5 mm. The negative electrode sheet includes a negative electrode current collector, a negative electrode active material layer covering both sides of the negative electrode current collector, and a negative electrode tab connected to or integrally formed with the negative electrode current collector. Insulating strips are arranged around the first positive electrode sheet, the second positive electrode sheet, and the negative electrode sheet. The first positive electrode current collector, the second positive electrode current collector, and the negative electrode current collector are metal wire meshes, the mesh width of the metal wire mesh is about 0.1-0.3 mm, the wire diameter is about 0.03-0.1 mm, and the ratio of the mesh width to the wire diameter is about 2:1-8:1, preferably 4:1-5:1. By controlling the parameters of the mesh width and wire diameter of the metal wire mesh, a current collector with appropriate thickness and porosity can be selected to balance the three requirements of the porous metal wire mesh current collector conductivity, light weight, and traction strength of the double-sided electrode material, thereby achieving efficient current collection of the current collector substrate, high-strength adhesion of the double-sided electrode material, and high energy density of the thick electrode sheet.

[0006] A single first positive electrode sheet or a second positive electrode sheet may be used at the outermost side of the battery cell or battery cell unit, and the remaining positive electrode sheets of the battery cell or battery cell unit all adopt a double-sheet structure, that is, the first positive electrode sheet and the second positive electrode sheet arranged side by side. The first positive electrode sheet and the second positive electrode sheet arranged side by side may not be connected to each other, or may be connected by an adhesive, and the adhesive may be conductive or non-conductive. The structure of the first positive electrode sheet and the second positive electrode sheet may be the same, and both are coated with positive electrode active material layers on both sides of the positive electrode current collector metal wire mesh. The thickness of the first positive electrode sheet and the second positive electrode sheet may be 0.2 to 1.5 mm. The negative electrode sheet is coated with negative electrode active material layers on both sides of the negative electrode current collector metal wire mesh. By setting a metal wire mesh with large mesh, fine wire diameter, and a large mesh width to wire diameter ratio, the electrode active material layers on both sides of the current collector can fully penetrate and fuse through the large mesh of the metal wire mesh during the coating process, thereby forming a firm attachment to the metal wire mesh. After the electrode sheets are dried, the electrode active material layers on both sides of the metal mesh form a whole, the electrode material layers on both sides pull each other, and have a greater grip on the metal mesh in the middle, so that the electrode material layers are not easy to fall off the metal mesh. In addition, a double-layer first positive electrode sheet and a second positive electrode sheet are arranged inside the battery cell, and a single-layer first positive electrode sheet or a second electrode sheet is arranged on the outermost side, so that there is no need to prepare edge electrode sheets separately, and all electrode materials can be fully utilized in a simple way to ensure the consistency of all battery cell units.

[0007] The positive electrode active material layer contains a positive electrode active material, a conductive agent, and a binder. The mass ratio of the positive electrode active material, the conductive agent, and the binder can be 90-98:0.5-5:0.5-5. The negative electrode active material layer contains a negative electrode active material, a conductive agent, and a binder. The mass ratio of the negative electrode active material, the conductive agent, and the binder of the negative electrode active material layer can be 90-98:0.5-5:0.5-5. The positive electrode active material may be one or more of lithium iron phosphate, lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium vanadium oxide, vanadium oxide, lithium manganese-based oxide (lithium manganese chromium oxide, lithium manganese cobalt oxide, lithium manganese nickel oxide, lithium manganese copper oxide), V[LiM]O4 (M = nickel or cobalt), polyatomic anion positive electrode materials (VOPO4, NASICON, silicates, titanates, sulfates, borates, R-Li3Fe2(PO4)3, Li3FeV(PO4)3, TiNb(PO4)3, LiFeNb(PO4)3), iron compounds, molybdenum oxides, etc. The negative electrode active material may be a carbon-based negative electrode material, nitride, silicon and silicide, tin-based oxide, selenide, alloy negative electrode material, titanium oxide, transition metal oxide, phosphide or metallic lithium, etc. Carbon-based negative electrode materials include one or more of graphite, mesophase carbon microspheres, graphitized carbon fibers, amorphous carbon materials, soft carbon, hard carbon, fullerenes, carbon nanotubes, carbon-cobalt composites, carbon-tin composites, and carbon-silicon composites; alloy negative electrode materials include one or more of tin-based alloys, silicon-based alloys, antimony-based alloys, germanium-based alloys, aluminum-based alloys, and lead-based alloys; transition metal oxides include one or more of cobalt oxides, nickel oxides, copper oxides, iron oxides, chromium oxides, and manganese oxides. Conductive agents may be one or more of carbon black, graphene, carbon nanotubes, carbon fibers, amorphous carbon, metal conductive particles, and metal conductive fibers. The material of the metal conductive particles or fibers may be aluminum, stainless steel, or silver. The adhesive may be SBR, polyacrylate, polytetrafluoroethylene, polyethylene oxide, sodium carboxymethyl cellulose, and alginate.

[0008] Preferably, the first positive current collector, the second positive current collector and the negative current collector are stainless steel wire mesh. The thickness of the stainless steel wire mesh can be 1μm to 2000μm, preferably 50μm to 1000μm. The current collector may also include an interface improvement layer, which may be compounded on the surface of the current collector by one or more of vacuum evaporation, magnetron sputtering, plasma deposition, spraying, bonding, mechanical pressing, printing or inkjet printing. The material of the interface improvement layer includes a conductive agent and a binder, and the mass ratio of the binder to the conductive agent may be 0.5 to 20: 99.5 to 80, or the interface improvement layer may only include a conductive agent.

[0009] In the positive electrode sheet, an intermediate positive electrode active material layer may also be provided between the first positive electrode sheet and the second positive electrode sheet. The thickness of the intermediate positive electrode active material layer may be 0.4 to 3 mm. The intermediate positive electrode active material layer contains part or all of the non-bonded and fixed positive electrode active conductive particles in a stacked state, and the stacked state includes powder stacking, pressed sheets or pressed blocks. In the liquid-free battery cell, the stacked porosity of the non-bonded and fixed positive electrode active conductive particles may be greater than 5% and less than 60%. When immersed in an electrolyte, the non-bonded and fixed positive electrode active conductive particles can move in the electrolyte and form a positive electrode slurry. In the intermediate positive electrode active material layer, the mass ratio of the positive electrode active material to the conductive agent may be 20 to 98: 80 to 2. The first positive electrode sheet and the second positive electrode sheet located on both sides of the intermediate positive electrode active material layer can prevent the positive electrode active conductive particles of the intermediate positive electrode active material layer in a slurry state from leaking from both sides. The insulating strip of the first positive electrode sheet is sealed and fitted with the insulating strip of the second positive electrode sheet, such as by bonding or hot melting, so as to prevent the positive active conductive particles of the intermediate positive electrode active material layer in the slurry state from leaking from the edges around the positive electrode sheet. By providing the intermediate positive electrode material active layer, the thickness of the positive electrode sheet can be further increased while avoiding the defect of material shedding caused by the excessive thickness of the electrode material layer coated on the first positive electrode sheet and the second positive electrode sheet. In addition, the internal slurry-state intermediate positive electrode active material layer can form a dynamic conductive network, making the conductive link inside the electrode better.

[0010] The coating thickness of the first inner positive electrode active material layer and the first outer positive electrode active material layer of the first positive electrode sheet may be different, and the coating thickness of the second inner positive electrode active material layer and the second outer positive electrode active material layer of the second positive electrode sheet may be different. The thickness of the first inner positive electrode active material layer and the second inner positive electrode active material layer may be the same, and the thickness of the first outer positive electrode active material layer and the second outer positive electrode active material layer may be the same. The thickness of the first inner positive electrode active material layer and the second inner positive electrode active material layer may be greater than the thickness of the first outer positive electrode active material layer and the second outer positive electrode active material layer. The thickness ratio of the inner positive electrode active material layer to the outer positive electrode active material layer is 1.2:1 to 4:1. The purpose of having different thicknesses of the inner positive electrode active material layer and the outer positive electrode active material layer is to enable the asymmetric positive electrode sheet to have the characteristics of small current, large capacity output and instantaneous high rate at the same time. For example, the inner positive electrode active material layer of the asymmetric positive electrode sheet can make the electrode sheet have a large capacity output at a small current, and the outer positive electrode active material layer of the asymmetric electrode sheet can make the electrode sheet have good instantaneous high rate characteristics. When the battery needs to be charged and discharged instantly and quickly, the outer positive electrode active material layer of the asymmetric electrode sheet will provide this characteristic; when the battery needs to have a large capacity and a small current output, the inner positive electrode active material layer of the asymmetric electrode sheet will provide this characteristic. Therefore, unlike traditional batteries that only unilaterally strengthen a certain characteristic of the battery, the asymmetric positive electrode sheet can take into account both the small current and large capacity output and the instantaneous high rate characteristics of the battery.

[0011] In the battery cell structure, the first positive pole ear and the second positive pole ear are located on one side of the battery cell, and the negative pole ear is located on the opposite side of the battery cell. The first positive pole ear and the second positive pole ear are arranged along the length direction of the positive electrode sheet. The length of the first positive pole ear and the second positive pole ear can be 15 to 50 mm, and the negative pole ear is arranged along the length direction of the negative electrode sheet, and the length of the negative pole ear can be 15 to 50 mm. The battery cell can be divided into multiple battery cell units, and all the positive pole ears of each battery cell unit are folded and welded into a positive pole ear cluster, and all the negative pole ears of each battery cell unit are folded and welded into a negative pole ear cluster. m pairs of mutually spaced positive electrode tab connecting sheets are welded on the positive electrode tab cluster of each battery cell unit, the positive electrode tab connecting sheets of multiple battery cell units are aligned up and down to form m groups of positive electrode tab connecting sheets, and the m groups of positive electrode tab connecting sheets are respectively welded together with the pole connecting sheets of m positive poles; m pairs of mutually spaced negative electrode tab connecting sheets are welded on the negative electrode tab cluster of each battery cell unit, the negative electrode tab connecting sheets of multiple battery cell units are aligned up and down to form m groups of negative electrode tab connecting sheets, and the m groups of negative electrode tab connecting sheets are respectively welded together with the pole connecting sheets of m negative poles, 2≤m≤10, preferably, 3≤m≤5.

[0012] A three-dimensional staggered channel guide plate may be arranged between two adjacent battery cell units. The three-dimensional staggered channel guide plate may include a first guide plate provided with a first guide hole and a second guide plate provided with a second guide hole. The first guide hole includes a plurality of first peripheral introduction holes located at the periphery of the first guide plate and opening toward the outside of the first guide plate, and a plurality of first internal guide holes located inside the first guide plate. The second guide hole includes at least a plurality of second internal guide holes located inside the second guide plate, and may also include a plurality of second peripheral introduction holes located at the periphery of the second guide plate and opening toward the outside of the second guide plate. The first guide hole and the second guide hole cross-overlap to form a three-dimensional staggered connecting channel extending between two adjacent battery cell units, so that the fluid can enter between two adjacent battery cell units from the periphery of the battery cell unit in multiple directions. By staggering and overlapping the guide holes on multiple guide plates, a three-dimensional connecting channel is formed to realize fluid transportation from the periphery of the three-dimensional staggered channel guide plate to its center, and then the fluid is promptly and quickly transported to the battery cell unit adjacent to the three-dimensional staggered channel guide plate, thereby solving the problem of slow infiltration speed or even inability to fully infiltrate the battery cell. The three-dimensional staggered channel guide plate can also be made of flexible plates, for example, a flexible first guide plate is wrapped on the outside of a battery cell unit, and a flexible second guide plate is wrapped on the outside of another battery cell unit. When the two battery cells are stacked, a three-dimensional staggered channel guide plate is formed between the two battery cells. The first guide hole and the second guide hole can form an inclination angle with the length direction of the guide plate, and the inclination angle is 15° to 75°. The inclined guide hole can make the guide plate not easy to warp and deform when wrapping the battery cell, even if it is subjected to tension parallel to and perpendicular to the direction of the battery cell unit, and can automatically form a staggered overlapping structure when the guide plate wraps the battery cell, without the need to repeatedly design multiple guide plate structures, which is convenient for process operation.

[0013] According to the utility model, an energy storage battery is also provided, which includes the battery cell as described above. The shell of the energy storage battery can adopt a semi-open structure, that is, an injection port for injecting fluid into the battery and a discharge port for discharging fluid from the battery are provided on the shell of the energy storage battery. Fluids such as electrolyte or safety agent can be injected into the battery through the injection port, and fluids such as electrolyte or safety agent can be discharged from the battery through the discharge port. The discharge port can also be used for routine exhaust. Combined with the characteristics of the semi-open energy storage battery, the battery isolation layer may not contain electrolyte when the battery leaves the factory, so that when the battery is transported to the user end or transfer station, no electrochemical reaction occurs inside the battery, and it can be safely transported as non-dangerous goods. The energy storage battery can be activated by injecting electrolyte into the battery through the injection port after the battery is safely transported to the user end or transfer station as non-dangerous goods when leaving the factory. At the same time, the energy storage battery can be maintained through the injection port and the discharge port for daily rehydration, exhaust and other maintenance, as well as emergency exhaust, discharge and injection of safety agent when the battery fails.

[0014] In the description of the present invention, it needs to be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right" and "top, bottom, inside, outside" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise stated, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention.

[0015] The advantages of the utility model are:

[0016] 1) The double-sided electrode coating is pulled and connected to each other on both sides of the metal wire mesh of the porous current collector, which solves the problem that the electrode active material is easily separated from the current collector after the thick electrode is dried;

[0017] 2) By setting up a multi-layer electrode active layer, the electrode active material can be utilized to the maximum extent. A non-bonded intermediate positive electrode active material layer can be set between the first positive electrode sheet and the second positive electrode sheet, which is conducive to forming a dynamic conductive network inside the electrode after liquid injection, thereby improving the electrode rate performance;

[0018] 3) A three-dimensional connecting channel is formed by staggered overlap of the guide holes on the multiple guide plates, so as to realize fluid transportation from the periphery of the three-dimensional staggered channel guide plate to the center thereof, and then the fluid is promptly and quickly transported to the battery cell unit adjacent to the three-dimensional staggered channel guide plate, thereby solving the problem of slow infiltration speed or even inability to fully infiltrate the battery cell, which is particularly suitable for large batteries and realizes rapid and full infiltration of the battery cell in a simple and reliable manner;

[0019] 4) The semi-open energy storage battery according to the utility model can realize battery maintenance, safe operation and safe transportation. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic cross-sectional view of a battery cell according to a first embodiment;

[0021] Figure 2 is a schematic cross-sectional view of a battery cell according to a second embodiment;

[0022] Figure 3 is a schematic cross-sectional view of a battery cell according to a third embodiment;

[0023] Figure 4 is a three-dimensional schematic diagram of a battery cell including a plurality of battery cell units;

[0024] Figure 5 is a schematic cross-sectional view of a battery cell including a plurality of battery cell units;

[0025] Figure 6(a)-Figure 6(c)It is a plan view of a three-dimensional staggered channel guide plate.

[0026] Reference numerals list

[0027] 1——Positive electrode

[0028] 1a——First positive electrode

[0029] 1b——Second positive electrode

[0030] 1c——Intermediate positive electrode active material layer

[0031] 101——Inner positive electrode active material layer

[0032] 102——Outer positive electrode active material layer

[0033] 2——Negative electrode

[0034] 201, 202——Negative electrode active material layer

[0035] 3 - Isolation layer

[0036] 401——Positive electrode tab

[0037] 402——Negative electrode tab

[0038] 4a——Aluminum mesh

[0039] 4b——Copper mesh

[0040] 4c——Stainless steel wire mesh

[0041] 5 - Insulation strip

[0042] 6——Battery Cell

[0043] 6a, 6b, 6c——Battery cell units

[0044] 7——Three-dimensional staggered channel guide plate

[0045] 701——First guide plate

[0046] 702——Second guide plate

[0047] 703——First diversion hole

[0048] 704——Second diversion hole DETAILED DESCRIPTION

[0049] The present invention will be further described below through embodiments in conjunction with the accompanying drawings.

[0050] Figure 1It is a schematic cross-sectional view of a battery cell according to the first embodiment. The battery cell 6 includes a cross-stacked positive electrode sheet 1 and a negative electrode sheet 2, and a separation layer 3 is arranged between the positive electrode sheet 1 and the negative electrode sheet 2. The positive electrode sheet 1 includes the same first positive electrode sheet 1a and the second positive electrode sheet 1b. A single first positive electrode sheet (or second positive electrode sheet) can be arranged on the outermost sides of the battery cell 6. Inside the battery cell 6, a positive electrode sheet 1 consisting of a first positive electrode sheet 1a and a second positive electrode sheet 1b arranged side by side can be arranged. The first positive electrode sheet 1a and the second positive electrode sheet 1b are coated with an inner positive electrode active material layer 101 and an outer positive electrode active material layer 102 of approximately the same thickness on both sides of a metal wire mesh such as an aluminum mesh 4a, and the inner positive electrode active material layer 101 of the first positive electrode sheet 1a is adjacent to the inner positive electrode active material layer 101 of the second positive electrode sheet 1b. An insulating strip 5 is arranged around the first positive electrode sheet 1a and the second positive electrode sheet 1b, and the insulating strip 5 can be coated on the edge of the metal wire mesh. The positive electrode tab 401 is electrically connected to or integrally formed with the metal wire mesh, and extends from one side of the battery cell 6. The negative electrode sheet 2 is a metal wire mesh such as a copper mesh 4b, on both sides of which negative electrode active material layers 201 and 202 of approximately the same thickness are respectively coated. An insulating strip 5 is provided around the negative electrode sheet 2, and the insulating strip 5 can be wrapped around the edge of the metal wire mesh. The negative electrode tab 402 is electrically connected to or integrally formed with the metal wire mesh, and extends from the other side of the battery cell 6. The length of the first positive electrode sheet 1a and the second positive electrode sheet 1b is 800mm, the width is 500mm, and the thickness is 1.1mm. The materials of the positive electrode active material layer are lithium iron phosphate, carbon nanotubes, and adhesives, with a mass ratio of 97:2:1. The length of the negative electrode sheet 2 is 800mm, the width is 500mm, and the thickness is 1.1mm. The materials of the negative electrode active material layer are graphite, conductive carbon black, and adhesives, with a mass ratio of 95:2:3. The mesh width of the metal wire mesh is about 0.3 mm, the wire diameter is about 0.06 mm, and the ratio of the mesh width to the wire diameter is about 5:1.

[0051] Figure 2 is a schematic cross-sectional view of a battery cell according to a second embodiment. Figure 1The main difference of the embodiment shown is that an intermediate positive electrode active material layer 1c is also included in the positive electrode sheet 1. The intermediate positive electrode active material layer 1c contains all non-bonded and fixed pressed sheet-shaped positive electrode active conductive particles. When immersed in the electrolyte, the non-bonded and fixed positive electrode active conductive particles can move in the electrolyte and form a positive electrode slurry. The insulating strip 5 around the first positive electrode sheet 1a is sealed and connected with the insulating strip 5 around the second positive electrode sheet 1b to prevent the positive electrode slurry of the intermediate active material layer 1c from leaking from the edge of the positive electrode sheet 1. The thickness of the first positive electrode sheet 1a and the second positive electrode sheet 1b is 1.2mm. The materials of the positive electrode active material layer are lithium iron phosphate, carbon black, and adhesive, with a mass ratio of 92:5:3, and the thickness of the intermediate positive electrode active material layer 1c is 1mm. The materials of the intermediate positive electrode active material layer 1c are lithium iron phosphate and carbon black, with a mass ratio of 70:30. The thickness of the negative electrode sheet 2 is 1.2mm. The negative electrode active material layer is made of graphite, carbon black and binder in a mass ratio of 95:4:1. The positive electrode current collector and the negative electrode current collector are metal meshes such as stainless steel mesh 4c, the mesh width of the metal mesh is about 0.24 mm, the wire diameter is about 0.03 mm, and the ratio of the mesh width to the wire diameter is about 8:1.

[0052] Figure 3 is a schematic cross-sectional view of a battery cell according to a third embodiment. Figure 1 The main difference between the illustrated embodiments is that the first positive electrode sheet 1a and the second positive electrode sheet 1b are asymmetric electrode sheets. The thickness of the inner positive electrode active material layer 101 of the first positive electrode sheet 1a and the second positive electrode sheet 1b is greater than the thickness of the outer positive electrode active material layer 102, and the thickness ratio of the inner positive electrode active material layer 101 to the outer positive electrode active material layer 102 is 3:1. The thicker inner positive electrode active material layer 101 of the first positive electrode sheet 1a is adjacent to the thicker inner positive electrode active material layer 101 of the second positive electrode sheet 1b, and is located in the middle of the entire positive electrode sheet, which enables the electrode sheet to have a large capacity output at a low current. The thinner outer positive electrode active material layer 102 of the first positive electrode sheet 1a and the thinner outer positive electrode active material layer 102 of the second positive electrode sheet 1b are located on the outside of the entire positive electrode sheet, which enables the electrode sheet to have good instantaneous high rate characteristics.

[0053] Figure 4It is a three-dimensional schematic diagram of a battery cell with multiple groups of battery cell units. In this example, the battery cell is divided into three battery cell units 6a, 6b, and 6c. The positive pole tab 401 is located on one side of the battery cell, and the negative pole tab 402 is located on the opposite side of the battery cell. The length of the positive pole tab 401 is 25 mm, and the length of the negative pole tab 402 is 25 mm. All the positive pole tabs of each battery cell unit are welded into a positive pole tab cluster. In the welding position of the positive pole tab cluster, multiple groups of positive pole tab connecting plates can be welded at approximately equal intervals, and each group of positive pole tab connecting plates is located on the upper and lower sides of the positive pole tab cluster. In the case of three groups of battery cell units 6a, 6b, and 6c, each positive pole tab connecting plate has a total of six (one group) positive pole tab connecting plates aligned vertically (such as Figure 4 In the embodiment of the present invention, as shown by the dashed line in the middle, there are five groups (m=5) of positive electrode tab connecting pieces, and the five groups of positive electrode tab connecting pieces can be electrically connected to the positive electrode column connecting pieces of the five positive electrode columns. Similarly, all the negative electrode tabs of each battery cell unit are welded into a negative electrode tab cluster. At the welding position of the negative electrode tab cluster, multiple groups of negative electrode tab connecting pieces can be welded at approximately equal intervals, and each group of negative electrode tab connecting pieces is located on the upper and lower sides of the negative electrode tab cluster. In the case of three groups of battery cell units 6a, 6b, and 6c, the welding position of each negative electrode tab connecting piece has a total of six (one group) negative electrode tab connecting pieces aligned up and down, and a total of five groups of negative electrode tab connecting pieces, and the five groups of negative electrode tab connecting pieces can be electrically connected to the negative electrode column connecting pieces of the five negative electrode columns.

[0054] Figure 5 The cross-sectional schematic diagram of a battery cell of multiple groups of battery cell units. The battery cell is provided with three battery cell units 6a, 6b, and 6c, and each battery cell unit is provided with a positive electrode sheet, a separator, and a negative electrode sheet, wherein the positive electrode sheet located at the outermost side of the battery cell unit includes a first positive electrode sheet, and the positive electrode sheet located inside the battery cell unit includes the same first positive electrode sheet and a second positive electrode sheet adjacent to each other. The first positive electrode sheet and the second positive electrode sheet both include a positive electrode active material layer and a positive electrode current collector, and the negative electrode sheet includes a negative electrode active material layer and a negative electrode current collector, and the separator is located between the positive electrode sheet and the negative electrode sheet. A three-dimensional staggered channel guide plate 7 is provided between the first positive electrode sheet at the lowermost side of the upper battery cell unit and the first positive electrode sheet at the uppermost side of the lower battery cell unit. A double-layer first positive electrode sheet and a second positive electrode sheet are provided inside the two battery cell units, and a single-layer first positive electrode sheet is provided at the outermost side, so that all electrode materials can be fully utilized without separately preparing edge electrode sheets, thereby ensuring the consistency of all battery cell units. The three-dimensional staggered channel guide plate 7 at least includes a stacked first guide plate 701 and a second guide plate 702. The fluid can enter between adjacent battery cells through the three-dimensional staggered channel guide plate 7, and then enter the adjacent battery cells from the connecting channels in the three-dimensional staggered channel guide plate 7, thereby infiltrating the battery cells on both sides of the three-dimensional staggered channel guide plate 7.

[0055] Figure 6(a)-Figure 6(c)It is a plan view of a three-dimensional staggered channel guide plate, wherein FIG. 6(a) is a plan view of a first guide plate, FIG. 6(b) is a plan view of a second guide plate, and FIG. 6(c) is a plan view of a stacked first guide plate and a second guide plate. The three-dimensional staggered channel guide plate 7 may include a first guide plate 701 and a second guide plate 702. As shown in FIG. 6(a), the first guide plate 701 is provided with a first guide hole 703 that penetrates the first guide plate, and a plurality of long strip-shaped first guide holes 703 are roughly evenly distributed on the first guide plate 701. The first guide hole 703 is further divided into a first peripheral introduction hole located at the periphery of the first guide plate and opening toward the outside of the first guide plate and a complete first internal guide hole located inside the first guide plate. The opening portion of the first peripheral introduction hole can introduce the fluid outside the three-dimensional staggered channel guide plate 7 into the three-dimensional staggered channel guide plate 7. The first guide hole 703 is inclined at an angle α relative to the length direction X of the guide plate, and the angle α can be 35°. As shown in FIG6(b), the second guide plate 702 is provided with a second guide hole 704 that passes through the second guide plate, and a plurality of long strip-shaped second guide holes 704 are roughly evenly distributed on the second guide plate 702. In this embodiment, the second guide hole 704 only includes a second internal guide hole. The second guide hole 704 is inclined at an angle β relative to the length direction X of the guide plate, and the angle β can be 35°. As shown in FIG6(c), when the first guide plate and the second guide plate are stacked, each first guide hole 703 (shown by a dotted line in the figure) has a portion that crosses and overlaps with the second guide hole 704, so that the fluid in the first guide hole 703 can flow into the second guide hole 704 that crosses and overlaps with it, and each second guide hole 704 also has a portion that crosses and overlaps with the first guide hole 703, so that the fluid in the second guide hole 704 can flow into the first guide hole 703 that crosses and overlaps with it. As shown in the figure, one end of the first peripheral introduction hole of the first guide plate overlaps with one end of the second internal guide hole of the second guide plate, and the other end of the second internal guide hole overlaps with one end of a first internal guide hole of the first guide plate, and the other end of the first internal guide hole overlaps with one end of another second internal guide hole of the second guide plate, and so on, thereby forming a three-dimensional staggered connecting channel between the first guide plate and the second guide plate.

[0056] The specific embodiments of the utility model are not intended to limit the utility model. Any technician familiar with the field can use the above-disclosed methods and technical contents to make many possible changes and modifications to the technical solution of the utility model without departing from the scope of the technical solution of the utility model, or modify it into an equivalent embodiment with equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the utility model without departing from the content of the technical solution of the utility model still falls within the scope of protection of the technical solution of the utility model.

Claims

1. A battery cell for an energy storage battery, characterized in that: The battery cell is composed of a positive electrode sheet and a negative electrode sheet cross-stacked, and an isolation layer is arranged between the positive electrode sheet and the negative electrode sheet. The positive electrode sheet is 200-1200 mm long, 100-500 mm wide, and 0.4-3.5 mm thick. The positive electrode sheet includes a first positive electrode sheet and a second positive electrode sheet. The first positive electrode sheet includes a first positive electrode collector, a first inner positive electrode active material layer and a first outer positive electrode active material layer covering both sides of the first positive electrode collector, and a first positive electrode tab connected to the first positive electrode collector. The second positive electrode sheet includes a second positive electrode collector, a second inner positive electrode active material layer and a second outer positive electrode material active layer covering both sides of the second positive electrode collector, and a second positive electrode tab connected to the second positive electrode collector. The first positive electrode sheet and The second positive electrode sheet is formed side by side in a manner that the first inner positive electrode active material layer and the second inner positive electrode active material layer are arranged opposite to each other. The length of the negative electrode sheet is 200-1200 mm, the width is 100-500 mm, and the thickness is 0.2-1.5 mm. The negative electrode sheet includes a negative electrode collector, a negative electrode active material layer covering both sides of the negative electrode collector, and a negative electrode tab connected to the negative electrode collector. Insulating strips are arranged around the first positive electrode sheet, the second positive electrode sheet, and the negative electrode sheet. The first positive electrode collector, the second positive electrode collector, and the negative electrode collector are metal wire meshes. The mesh width of the metal wire mesh is 0.1-0.3 mm, the wire diameter is 0.03-0.1 mm, and the ratio of the mesh width to the wire diameter is 2:1-8:

1.

2. The battery cell of the energy storage battery according to claim 1, characterized in that: The first positive electrode current collector, the second positive electrode current collector and the negative electrode current collector are stainless steel wire meshes.

3. The battery cell of the energy storage battery according to claim 1, characterized in that: In the positive electrode sheet, an intermediate positive electrode active material layer is arranged between the first positive electrode sheet and the second positive electrode sheet, and the intermediate positive electrode active material layer contains part or all of the non-bonded and fixed stacked positive electrode active conductive particles, and the stacked state includes powder stacking, pressed sheet or pressed block, and the insulating strip of the first positive electrode sheet is sealed and fitted with the insulating strip of the second positive electrode sheet.

4. The battery cell of the energy storage battery according to claim 1, characterized in that: The coating thicknesses of the first inner positive electrode active material layer and the first outer positive electrode active material layer of the first positive electrode sheet are different, the coating thicknesses of the second inner positive electrode active material layer and the second outer positive electrode active material layer of the second positive electrode sheet are different, the thickness of the first inner positive electrode active material layer and the second inner positive electrode active material layer are the same, the thickness of the first outer positive electrode active material layer and the second outer positive electrode active material layer are the same, and the thicknesses of the first inner positive electrode active material layer and the second inner positive electrode active material layer are greater than the thicknesses of the first outer positive electrode active material layer and the second outer positive electrode active material layer.

5. The battery cell of the energy storage battery according to claim 1, characterized in that: The first positive electrode tab and the second positive electrode tab are located on one side of the battery cell, and the negative electrode tab is located on the opposite side of the battery cell. The first positive electrode tab and the second positive electrode tab are arranged along the length direction of the positive electrode sheet, and the length of the first positive electrode tab and the second positive electrode tab is 15 to 50 mm. The negative electrode tab is arranged along the length direction of the negative electrode sheet, and the length of the negative electrode tab is 15 to 50 mm.

6. The battery cell of the energy storage battery according to claim 5, characterized in that: The battery cell is divided into a plurality of battery cell units, all positive pole tabs of each battery cell unit are folded and welded to form a positive pole tab cluster, and all negative pole tabs of each battery cell unit are folded and welded to form a negative pole tab cluster.

7. The battery cell of the energy storage battery according to claim 6, characterized in that: m pairs of mutually spaced positive pole tab connecting sheets are welded on the positive pole tab cluster of each battery cell unit, the positive pole tab connecting sheets of multiple battery cell units are aligned up and down to form m groups of positive pole tab connecting sheets, and the m groups of positive pole tab connecting sheets are respectively welded together with the pole tab connecting sheets of m positive poles; m pairs of mutually spaced negative pole tab connecting sheets are welded on the negative pole tab cluster of each battery cell unit, the negative pole tab connecting sheets of multiple battery cell units are aligned up and down to form m groups of negative pole tab connecting sheets, and the m groups of negative pole tab connecting sheets are respectively welded together with the pole tab connecting sheets of m negative poles, 2≤m≤10.

8. The battery cell of the energy storage battery according to claim 6, characterized in that: A three-dimensional staggered channel guide plate is arranged between two adjacent battery cell units, and the three-dimensional staggered channel guide plate includes a first guide plate provided with a first guide hole and a second guide plate provided with a second guide hole, the first guide hole includes a plurality of first peripheral introduction holes located at the periphery of the first guide plate and opening toward the outside of the first guide plate, and a plurality of first internal guide holes located inside the first guide plate, the second guide holes include at least a plurality of second internal guide holes located inside the second guide plate, the first guide holes cross-overlap with the second guide holes to form a three-dimensional staggered connecting channel extending between two adjacent battery cell units, so that the fluid can enter between two adjacent battery cell units from the periphery of the battery cell units along multiple directions.

9. The battery cell of the energy storage battery according to claim 8, characterized in that: The first guide hole and the second guide hole form an inclination angle with the length direction of the guide plate, and the inclination angle is 15° to 75°.

10. An energy storage battery, characterized in that: The energy storage battery comprises the battery cell as described in any one of claims 1 to 9, and the energy storage battery also comprises a shell, the battery cell is accommodated in the shell, and the shell is provided with an injection port for injecting fluid into the interior of the battery and a discharge port for discharging fluid from the interior of the battery.

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