Solid-state battery and manufacturing method of solid-state battery

Abstract

The invention belongs to the technical field of solid-state batteries, and discloses a solid-state battery and a manufacturing method of the solid-state battery, the solid-state battery comprises a pole piece and a solid-state electrolyte, the pole piece comprises a pole piece body and a tab, the surface of the tab is coated with a reinforcing layer, and the reinforcing layer at least covers the joint of the pole piece body and the tab. And the ratio of the size of the reinforcing layer along the first direction to the size of the tab along the first direction is 0.2-1.2. According to the solid-state battery, the phenomenon of brittle failure of the tabs under relatively high pressure can be well avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of solid-state batteries, and in particular to a solid-state battery and a method for manufacturing the solid-state battery. Background Art

[0002] The assembly process of all-solid-state batteries requires great pressure for pressing. Generally, an isostatic press or a warm isostatic press is used with a pressure range of 200MPa-1000MPa. Under high pressure, the material of the pole ear on the pole piece becomes brittle, and the pole ear is prone to brittle fracture under shear force, resulting in a short circuit between the battery and the external part, making it impossible to test. Summary of the invention

[0003] The first object of the present invention is to provide a solid-state battery that can better avoid the brittle fracture of the tab under high pressure.

[0004] The second object of the present invention is to provide a method for manufacturing a solid-state battery, which can better avoid the problem of tab breakage during the process of pressing the pole pieces.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] The present invention discloses a solid-state battery, comprising a pole piece and a solid electrolyte, wherein the pole piece comprises a pole piece body and a pole ear, wherein the surface of the pole ear is coated with a reinforcing layer, and the reinforcing layer at least covers the connection between the pole piece body and the pole ear; wherein the ratio of the size of the reinforcing layer along a first direction to the size of the pole ear along the first direction is 0.2-1.2, and the first direction is the direction in which the pole ear is led out relative to the pole piece body.

[0007] The beneficial effects of the solid-state battery of the present invention are as follows: since the surface of the pole ear is coated with a reinforcing layer, the reinforcing layer covers the connection between the pole piece body and the pole ear, thereby improving the strength of the pole ear. Under higher pressure, the shrinkage of the pole ear with greater strength is relatively small, and it is not easy to shrink and become brittle, thereby avoiding the phenomenon of brittle fracture of the pole ear. And the ratio of the size of the reinforcing layer along the first direction to the pole ear along the first direction is controlled within the range of 0.2-1.2, on the one hand, it is ensured that the reinforcing layer can cover enough pole ear areas to ensure the reinforcing effect on the pole ear, and on the other hand, it avoids the problem of material waste and useless size increase caused by the excessive size of the reinforcing layer.

[0008] The present invention also discloses a method for manufacturing a solid-state battery, comprising the following steps:

[0009] Forming reinforcement layers on the positive electrode ear of the positive electrode sheet and the negative electrode ear of the negative electrode sheet respectively;

[0010] The plurality of positive electrode sheets and the plurality of negative electrode sheets are stacked in sequence and pressed into a battery cell, the positive electrode ears of the plurality of positive electrode sheets are stacked to form a positive electrode ear piece, and the negative electrode ears of the plurality of negative electrode sheets are stacked to form a negative electrode ear piece;

[0011] The positive electrode connector and the negative electrode connector are respectively connected to the positive electrode ear member and the negative electrode ear member to serve as the lead-out structure of the battery cell.

[0012] The beneficial effects of the manufacturing method of the solid-state battery of the present invention are as follows: in the actual processing process, the tabs of the positive electrode sheet and the negative electrode sheet are subjected to secondary processing, and a conductive metal foil is fixed to the tabs by bonding or pressing as a reinforcement layer. After the pretreatment is completed, multiple positive electrode sheets and multiple negative electrode sheets are pressed together to form a battery cell. During the pressing process, since the reinforcement layer is provided on both the positive electrode tab and the negative electrode tab, the strength of the positive electrode tab and the negative electrode tab is improved. Under higher pressure, the positive electrode tab and the negative electrode tab with greater strength shrink relatively less, and are not prone to shrinkage and brittleness, thereby avoiding the brittle fracture of the positive electrode tab and the negative electrode tab.

[0013] The present invention also discloses a method for manufacturing a solid-state battery, comprising the following steps:

[0014] The plurality of positive electrode sheets and the plurality of negative electrode sheets are stacked in sequence, a solid electrolyte is arranged between the positive electrode sheets and the negative electrode sheets, and then pressed into a battery cell, and the positive electrode ears of the plurality of positive electrode sheets are stacked to form a positive electrode ear piece, and the negative electrode ears of the plurality of negative electrode sheets are stacked to form a negative electrode ear piece;

[0015] Disposing a reinforcement layer on the outer side of the negative electrode ear piece and / or the positive electrode ear piece;

[0016] The positive electrode connector and the negative electrode connector are respectively connected to the positive electrode ear member and the negative electrode ear member to serve as the lead-out structure of the battery cell.

[0017] The manufacturing method of the solid-state battery of the present invention has the beneficial effects of: the positive ear piece and the negative ear piece are subjected to secondary processing, and a conductive metal foil is fixed to the positive ear piece and / or the negative ear piece by bonding or pressing as a reinforcement layer. In the multi-layer positive ear, the inner positive ear is reinforced by the outer positive ear, and the outer positive ear is reinforced by the reinforcement layer; in the multi-layer negative ear, the inner negative ear is reinforced by the outer negative ear, and the outer negative ear is reinforced by the reinforcement layer, thereby improving the strength of the positive ear piece and the negative ear piece. Under higher pressure, the positive ear piece and the negative ear piece with greater strength shrink relatively less, and are not prone to shrinkage and brittleness, thereby avoiding the brittle fracture of the positive ear piece and the negative ear piece.

[0018] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic structural diagram of a positive electrode sheet according to an embodiment of the present invention;

[0020] Figure 2 yes Figure 1 A schematic cross-sectional view of the positive electrode sheet in FIG.

[0021] Figure 3 is a schematic structural diagram of a negative electrode sheet according to an embodiment of the present invention;

[0022] Figure 4 yes Figure 3 A schematic cross-sectional view of the negative electrode sheet in FIG.

[0023] Figure 5 Schematic diagram of the structure of the pole piece of the embodiment of the present invention.

[0024] Reference numerals:

[0025] 100, pole piece body; 200, pole ear; 300, reinforcement layer; 400, insulation layer; 500, arc-shaped transition portion. DETAILED DESCRIPTION

[0026] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0027] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" 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 a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] In the description of this embodiment, the terms "upper", "lower", "left", "right", "front", "rear" and other directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operate in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0029] Reference below Figure 1-Figure 5 The specific structure of the solid-state battery of a specific embodiment of the present invention is described.

[0030] The present invention discloses a solid-state battery, comprising a pole piece and a solid-state electrolyte, Figure 1 and Figure 3 As shown, the pole piece includes a pole piece body 100 and a pole lug 200, and the surface of the pole lug 200 is coated with a reinforcing layer 300, and the reinforcing layer 300 at least covers the connection between the pole piece body 100 and the pole lug 200, and the ratio of the size of the reinforcing layer 300 along the first direction to the size of the pole lug 200 along the first direction is 0.2-1.2, and the first direction is the direction in which the pole lug 200 is led out relative to the pole piece body 100. First of all, it should be noted that the solid-state battery includes a positive pole piece and a negative pole piece, and the above-mentioned reinforcing layer 300 is provided on both the positive pole piece and the negative pole piece, or is provided on only one of the positive pole piece and the negative pole piece, but because the working principle of the reinforcing layer 300 is the same, the pole piece is used as the description object in the description of the parameters related to the reinforcing layer 300 below, and the positive pole piece and the negative pole piece are not distinguished.

[0031] It is understandable that in the solid-state battery disclosed in the present invention, since the surface of the pole tab 200 is coated with a reinforcing layer 300, the reinforcing layer 300 covers the connection between the pole piece body 100 and the pole tab 200, thereby improving the strength of the pole tab 200. Under higher pressure, the pole tab 200 with greater strength shrinks relatively less, and is not prone to shrinkage and brittleness, thereby avoiding the phenomenon of brittle fracture of the pole tab 200. The ratio of the size of the reinforcing layer 300 along the first direction to the size of the pole tab 200 along the first direction can be 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, and other values ​​between 0.2-1.2 can also be selected, and are not limited to the above examples. In the actual lamination process, if the ratio of the size of the reinforcing layer 300 along the first direction to the size of the tab 200 along the first direction is too small, the reinforcing layer 300 will only cover a small part of the tab 200, and the reinforcing effect on the tab 200 will be limited, thereby increasing the risk of the tab 200 breaking during the lamination process. If the ratio of the size of the reinforcing layer 300 along the first direction to the size of the tab 200 along the first direction is too large, the length of the reinforcing layer 300 extending out of the tab 200 along the first direction will be too large, affecting the effective welding area of ​​the tab 200. In this embodiment, the ratio of the size of the reinforcing layer 300 along the first direction to the size of the tab 200 along the first direction is controlled within the range of 0.2-1.2, which, on the one hand, ensures that the reinforcing layer 300 can cover a sufficient area of ​​the tab 200 to ensure the reinforcing effect on the tab 200, and on the other hand, avoids the phenomenon that the effective welding area of ​​the tab 200 is reduced due to the excessive size of the reinforcing layer 300.

[0032] Optionally, the size of the tab 200 along the first direction is 3 mm-60 mm, and the size of the reinforcing layer 300 along the first direction is 0.5 mm-90 mm. Thus, on the one hand, it is ensured that the reinforcing layer 300 can cover a sufficient area of ​​the tab 200 to ensure the reinforcing effect on the tab 200, and on the other hand, it is avoided that the size of the reinforcing layer 300 is too large, resulting in a decrease in the effective welding area of ​​the tab 200.

[0033] Optionally, the first end of the reinforcing layer 300 along the first direction is flush with the connection between the pole piece body 100 and the pole tab 200. It is understandable that during the processing of the pole piece, the pole piece body 100 includes a current collector and an active material layer covering the current collector, and the reinforcing layer 300 is flush with the first end of the pole tab 200 lead-out direction and the connection between the pole piece body 100 and the pole tab 200. It should be noted that if the reinforcing layer 300 extends onto the active material layer, the distance between the pole piece and the adjacent pole piece will be increased, thereby increasing the transmission impedance of lithium ions between the pole pieces. In this embodiment, the first end of the reinforcing layer 300 along the lead-out direction of the pole tab 200 and the connection between the pole piece body 100 and the pole tab 200 are flush to ensure that the reinforcing layer 300 will not contact the active material layer on the pole piece body 100 during the process of reinforcing the pole tab 200, thereby avoiding the reinforcing layer 300 from causing adverse effects on the active material layer.

[0034] Optionally, the second end of the reinforcing layer 300 along the first direction is aligned with the end of the pole lug 200 away from the pole piece body 100. It is understandable that in the process of actually attaching the reinforcing layer 300 to the pole piece body 100, it is convenient to take the reinforcing layer 300 or to coat it, which is beneficial for the operator to form the reinforcing layer 300 on the pole lug 200. At the same time, it is also possible to achieve uniform reinforcement of the pole lug 200, further reducing the risk of the pole lug 200 breaking. Further preferably, the second end of the reinforcing layer 300 along the direction of the pole lug 200 leading out exceeds the end of the pole lug 200, that is, the reinforcing layer 300 is formed into a U-shaped structure wrapped on the pole lug 200. When the reinforcing layer 300 is a sheet material bonded or pressed on the pole lug 200, this structure can improve the connection strength between the reinforcing layer 300 and the pole lug 200, and avoid the reinforcing layer 300 from falling off the pole lug 200.

[0035] Optionally, the thickness of the reinforcing layer 300 is 3 μm-100 μm. The thickness of the reinforcing layer 300 can be 3 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm. Of course, the thickness of the reinforcing layer 300 can also be other values ​​of 3 μm-100 μm, and is not limited to the above examples. It should be noted that, in the actual lamination process, if the thickness of the reinforcing layer 300 is too small, on the one hand, it is not easy to attach the reinforcing layer 300 to the pole lug 200, and the thinner reinforcing layer 300 is easily damaged or falls off the reinforcing layer 300, and on the other hand, the reinforcing effect on the pole lug 200 is limited, thereby increasing the risk of the pole lug 200 breaking during the lamination process; if the thickness of the reinforcing layer 300 is too large, the thickness of some areas of the pole piece will be too large, and the excessive thickness is not conducive to lamination and will reduce the energy density of the solid-state battery. In this embodiment, the thickness of the reinforcing layer 300 is controlled within 3μm-100μm. On the one hand, the reinforcing layer 300 can be easily attached to the pole lug 200 and the probability of the reinforcing layer 300 being damaged can be reduced. On the other hand, the thickness of the entire pole piece can be controlled, ensuring that the pole lug 200 has sufficient strength to avoid the pole lug 200 from breaking while improving its energy density.

[0036] Optionally, the ratio of the thickness of the reinforcing layer 300 to the thickness of the tab 200 is 0.1-15. The ratio of the thickness of the reinforcing layer 300 to the thickness of the tab 200 can be 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15. Of course, the ratio of the thickness of the reinforcing layer 300 to the thickness of the tab 200 can also be other values ​​within the range of 0.1-15, and is not limited to the above examples. It should be noted that in the actual production and manufacturing process, for certain specific types of pole pieces, the pole lug 200 may be too thin or too thick relative to the common size. For the pole lug 200 of special thickness, limiting the thickness of the reinforcement layer 300 by a specific size may not be able to meet special needs well. In this embodiment, the ratio of the thickness of the reinforcement layer 300 to the thickness of the pole lug 200 is used as a limitation on the thickness of the reinforcement layer 300. In this way, no matter what the specific thickness of the pole lug 200 is, the thickness of the reinforcement layer 300 can be selected according to the above ratio, so that the reinforcement layer 300 can be easily attached to the pole lug 200 and the probability of the reinforcement layer 300 being damaged can be reduced, and the thickness of the entire pole piece can be controlled, which is beneficial to improving its energy density.

[0037] Of course, in other embodiments of the present invention, according to the strength requirements of the pole lug 200 and the parameter sizes of the pole lug 200, the thickness of the reinforcing layer 300 and the ratio of the thickness of the reinforcing layer 300 to the thickness of the pole lug 200 can be adjusted according to specific needs and are not limited to the above-mentioned limited range.

[0038] Optionally, the reinforcing layer 300 is a conductive material. Conductive materials include, but are not limited to, aluminum, copper, nickel, stainless steel, and other materials. During the processing of the solid-state battery, after the pressing is completed, the pole tabs 200 between the multiple pole pieces need to be connected to the structure. The reinforcing layer 300 is made of a conductive material, which ensures that the strength of the pole tabs 200 is improved while not affecting the conduction between the multiple pole tabs 200, which is conducive to ensuring the reliability of the solid-state battery.

[0039] Optionally, when the ratio of the thickness of the reinforcing layer 300 to the thickness of the tab 200 is less than 0.1, the ratio of the dimension of the reinforcing layer 300 along the first direction to the dimension of the tab 200 along the first direction is 0.3-1.

[0040] Optionally, the electrode sheet includes a positive electrode sheet and a negative electrode sheet, and the thickness of the reinforcing layer 300 on the positive electrode ear of the positive electrode sheet is 3μm-100μm. The thickness of the reinforcing layer 300 on the negative electrode ear of the negative electrode sheet is 3μm-50μm. It can be understood that, under normal circumstances, the material for manufacturing the positive electrode sheet is copper, and the material for manufacturing the negative electrode sheet is copper. Compared with the negative electrode ear, the risk of fracture of the positive electrode ear may be greater, which is fed back to the reinforcing layer 300. The thickness of the reinforcing layer 300 on the positive electrode ear is also relatively thicker than the reinforcing layer 300 on the negative electrode ear. In this embodiment, the thickness of the reinforcing layer 300 on the positive electrode ear of the positive electrode sheet is 3μm-100μm. The thickness of the reinforcing layer 300 on the negative electrode ear of the negative electrode sheet is 3μm-50μm, which can ensure the strength of the positive and negative electrodes, thereby ensuring the structural stability of the positive and negative electrodes.

[0041] Optionally, the positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer, the material of the positive electrode current collector may be metal aluminum or an aluminum alloy, and when the thickness of the positive electrode active material layer is greater than or equal to 240 μm, the thickness of the reinforcing layer 300 on the positive electrode ear is 10 μm-100 μm. It can be understood that when the thickness of the positive electrode active material layer is greater than or equal to 240 μm, the stress difference between the positive electrode active material layer and the positive electrode current collector is large, and the risk of fracture at the connection between the positive electrode current collector and the positive electrode ear increases. Therefore, controlling the thickness of the reinforcing layer 300 on the positive electrode ear within the range of 10 μm-100 μm is conducive to reducing the risk of fracture at the connection between the positive electrode current collector and the positive electrode ear, and ensuring the structural stability of the positive electrode sheet.

[0042] Further optionally, the thickness of the positive electrode active material layer is 240μm-500μm. Specifically, the thickness of the positive electrode active material layer can be 240μm, 250μm, 260μm, 270μm, 280μm, 290μm, 300μm, 310μm, 320μm, 330μm, 340μm, 350μm, 360μm, 370μm, 380μm, 390μm, 400μm, 410μm, 420μm, 430μm, 440μm, 450μm, 460μm, 470μm, 480μm, 490μm, 500μm.

[0043] For the pole piece body 100, the pole piece body 100 generally includes a current collector and an active material layer covering the current collector, and the ratio of the thickness of the active material layer to the thickness of the current collector is greater than or equal to 10. The ratio of the size of the reinforcing layer 300 along the second direction to the size of the pole tab 200 along the second direction is in the range of 0.5-1, and the second direction is perpendicular to the first direction; the ratio of the size of the reinforcing layer 300 along the first direction to the pole tab 200 along the first direction is 0.35-1.2. It can be understood that since the ratio of the active material layer thickness to the current collector is greater than or equal to 10, the thickness difference between the two is relatively large. During the transportation or charging and discharging process of the electrode, the stress difference between the two is relatively large, and the risk of fracture at the connection between the electrode body 100 and the electrode tab 200 increases. In this embodiment, the ratio of the size of the reinforcement layer 300 along the second direction to the size of the electrode tab 200 along the second direction is controlled within the range of 0.5-1, and the ratio of the size of the reinforcement layer 300 along the first direction to the electrode tab 200 along the first direction is controlled within the range of 0.35-12, which is beneficial to reduce the risk of fracture at the connection between the electrode body 100 and the electrode tab 200.

[0044] Optionally, the reinforcing layer 300 is arranged around the circumference of the pole tab 200, and the reinforcing layer 300 has a head end and a tail end, and the head end and the tail end have an overlapping area or the head end and the tail end are butted in the direction around the pole tab 200; wherein: the ratio of the size of the reinforcing layer 300 along the first direction to the pole tab 200 along the first direction is 0.25-1. It can be understood that, compared with the reinforcing layer 300 attached to both sides of the pole tab 200 along its thickness direction, the reinforcing layer 300 structure wound on the pole tab 200 is selected in this embodiment, and this reinforcing layer 300 has a better reinforcing effect, so the length of the pole tab 200 covered along the first direction can be relatively small. In this embodiment, it is only necessary to control the ratio of the size of the reinforcing layer 300 along the first direction to the pole tab 200 along the first direction within the range of 0.25-1 to ensure that the pole tab 200 will not break.

[0045] Optionally, an arc-shaped transition portion 500 is provided between the pole tab 200 and the pole piece body 100, and the ratio of the size of the reinforcing layer 300 along the first direction to the pole tab 20) along the first direction is 0.2-1. It can be understood that the arc-shaped transition portion 500 is provided between the pole tab 200 and the pole piece body 100, and the arc-shaped transition portion 500 can improve the stress condition at the connection between the pole tab 200 and the pole piece body 100, and the arc-shaped transition portion 500 itself can play a certain role in preventing the pole tab 200 from breaking. Therefore, in this embodiment, it is only necessary to control the ratio of the size of the reinforcing layer 300 along the first direction to the pole tab 200 along the first direction within the range of 0.2-1 to ensure that the pole tab 200 will not break.

[0046] Further optionally, the reinforcement layer 300 is disposed to cover the arc-shaped transition portion 500 , thereby better ensuring the reinforcement effect of the reinforcement layer 300 on the tab 200 .

[0047] In the prior art, under high pressure, if there is no brittle fracture at the pole ear 200, a short circuit problem is prone to occur. This is because the shear force generated at the stack between the pole pieces under high pressure is caused. In order to solve this problem, an insulating layer 400 can also be provided on the reinforcing layer 300. Specifically, the pole piece includes a positive pole piece and a negative pole piece, and an insulating layer 400 is also provided on the side of the reinforcing layer 300 disposed on the positive pole piece away from the pole ear 200. In this embodiment, by adding an insulating layer 400 to the outer side of the reinforcing layer 300 of the positive pole piece, the insulating layer 400 can ensure that the positive pole ear of the positive pole piece and the negative pole ear of the negative pole piece will not short-circuit even when the shear force generated under high pressure causes the two to contact, thereby helping to improve the reliability of the solid-state battery.

[0048] Optionally, the thickness of the insulating layer 400 is 3 μm-100 μm. The thickness of the insulating layer 400 can be 3 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm. Of course, the thickness of the insulating layer 400 can also be other values ​​of 3 μm-100 μm, and is not limited to the above examples. It should be noted that in the actual lamination process, if the thickness of the insulating layer 400 is too small, it is not easy to attach the insulating layer 400 to the reinforcing layer 300, and the thinner insulating layer 400 is easily damaged or falls off from the reinforcing layer 300; if the thickness of the insulating layer 400 is too large, the thickness of some areas of the pole piece will be too large, and excessive thickness is not conducive to lamination and will reduce the energy density of the solid-state battery. In this embodiment, the thickness of the insulating layer 400 is controlled within 3μm-100μm. On the one hand, the insulating layer 400 can be easily attached to the pole ear 200 and the probability of the insulating layer 400 being damaged can be reduced. On the other hand, the thickness of the entire pole piece can be controlled, which is beneficial to improving its energy density.

[0049] Optionally, the size of the insulating layer 400 along the second direction is greater than or equal to the size of the reinforcing layer 300 along the second direction. Thus, the insulating effect of the insulating layer 400 can be ensured, the possibility of contact between the reinforcing layer 300 on the positive electrode ear and the reinforcing layer 300 on the negative electrode ear can be avoided, and the short circuit phenomenon of the solid-state battery can be minimized.

[0050] Optionally, the size of the negative electrode sheet along the second direction is greater than the size of the positive electrode sheet along the second direction, and the difference between the size of the negative electrode sheet along the second direction and the size of the positive electrode sheet along the second direction is set as a reference size, and the difference between the size of the insulating layer 400 along the second direction and the reference size is 0.1mm-10mm. The difference between the size of the insulating layer 400 along the second direction and the reference size can be 0.1mm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, 10mm. Of course, the difference between the size of the insulating layer 400 along the second direction and the reference size can also be other values ​​within the range of 0.1mm-10mm, and is not limited to the above examples. It is understandable that in the field of solid-state battery technology, the portion of the negative electrode sheet that exceeds the positive electrode sheet is called the Overhang area. The main function of the Overhang area is to allow the negative electrode sheet to have sufficient lithium storage space to prevent the lithium ions released from the positive electrode sheet from reaching the negative electrode sheet. If there is not enough lithium insertion space, lithium deposition will occur on the negative electrode sheet. In this embodiment, the area of ​​the Overhang area is used as the design basis for the size of the insulating layer 400 along the second direction, which can ensure that after the insulating layer 400 is added to the tab 200 of the positive electrode sheet, lithium deposition on the negative electrode sheet can be avoided to the greatest extent, and the short circuit between the positive electrode sheet and the negative electrode sheet can be avoided, thereby ensuring the working reliability of the solid-state battery.

[0051] Optionally, the insulating layer 400 includes at least one of an insulating tape and an epoxy resin coating. It is understandable that, in the actual processing, the insulating tape can be directly attached to the reinforcing layer 300, or the epoxy resin coating can be sprayed on the surface of the reinforcing layer 300 to form the insulating layer 400. Of course, the insulating layer 400 can also be a multi-layer mixed structure. In the embodiment of the present invention, the insulating layer 400 only needs to ensure the insulation effect, and the specific material and formation method can be selected according to the actual processing needs.

[0052] Optionally, the pole piece includes a plurality of stacked pole piece bodies 100, and the reinforcing layer 300 is arranged on the outer pole ear 200 among the plurality of pole ears 200. It is understandable that in the actual production process, the pole piece may only include one pole piece body 100 and the pole ear 200 connected to the pole piece body 100. Of course, the pole piece may also be a structure stacked by a plurality of pole piece bodies 100. In this case, the pole ear 200 of the pole piece is also a multi-layer structure, and the strength of the inner pole ear 200 is strengthened by the outer pole ear 200, and the outer pole ear 200 is strengthened by setting the reinforcing layer 300, so that each pole ear 200 can play a good reinforcing role, thereby avoiding the pole ear 200 from breaking.

[0053] The present invention also discloses a method for manufacturing a solid-state battery, which includes the following steps: forming a reinforcing layer 300 on the positive ear of the positive electrode sheet and the negative ear of the negative electrode sheet respectively; stacking a plurality of positive electrode sheets and a plurality of negative electrode sheets in sequence, arranging a solid electrolyte between the positive electrode sheets and the negative electrode sheets, and then pressing them into a battery cell, and the positive electrode ears of the plurality of positive electrode sheets are stacked to form a positive electrode ear piece, and the negative electrode ears of the plurality of negative electrode sheets are stacked to form a negative electrode ear piece; connecting the positive electrode connector and the negative electrode connector to the positive electrode ear piece and the negative electrode ear piece respectively to serve as the lead-out structure of the battery cell.

[0054] It is understandable that the manufacturing process of the positive electrode sheet and the negative electrode sheet can be selected according to actual needs, and the processing process of the positive electrode sheet and the negative electrode sheet is not limited here. In the actual processing process, the tabs 200 of the positive electrode sheet and the negative electrode sheet are subjected to secondary processing, and a conductive metal foil is fixed to the tabs 200 by bonding or pressing as a reinforcing layer 300. After the pre-processing is completed, multiple positive electrode sheets and multiple negative electrode sheets are pressed to form a battery cell. During the pressing process, since the reinforcing layer 300 is provided on both the positive electrode tab and the negative electrode tab, the strength of the positive electrode tab and the negative electrode tab is improved. Under higher pressure, the shrinkage of the stronger positive electrode tab and the negative electrode tab is relatively small, and it is not easy to shrink and become brittle, thereby avoiding the brittle fracture of the positive electrode tab and the negative electrode tab. After the connection is completed, the positive connector and the negative connector are respectively connected to the positive ear piece and the negative ear piece to serve as the lead-out structure of the battery cell. This can facilitate the lead-out of the battery cell. The positive connector and the negative connector can be selected according to actual needs, and the connection method can also be adjusted according to actual needs.

[0055] It should be supplemented that, in the prior art, in order to ensure the current flow capacity, each positive electrode sheet and each negative electrode sheet must be provided with a positive electrode ear and a negative electrode ear respectively, and in the present embodiment, by adding a conductive reinforcement layer 300, the current flow capacity of the positive electrode ear and the negative electrode ear is enhanced. In the actual assembly process, it is not necessary to provide a positive electrode ear and a negative electrode ear on each positive electrode sheet and each negative electrode sheet as in the prior art. The number of positive electrode ears and negative electrode ears can be appropriately reduced, that is, a part of the electrode sheets without electrode ears are used for stacking, which is conducive to reducing costs.

[0056] Optionally, after winding at least one circle of the reinforcing layer 300 on the positive electrode ear, the reinforcing layer 300 is covered with the insulating layer 400; or at least one reinforcing layer 300 is provided on both sides of the positive electrode ear, and the reinforcing layer 300 is covered with the insulating layer 400. By adding an insulating layer 400 on the outer side of the reinforcing layer 300 of the positive electrode sheet, the insulating layer 400 can ensure that the positive electrode ear of the positive electrode sheet and the negative electrode ear of the negative electrode sheet will not short-circuit even when the shear force generated under high pressure causes the two to contact, thereby helping to improve the reliability of the solid-state battery.

[0057] The present invention also discloses a method for manufacturing a solid-state battery, comprising the following steps: stacking a plurality of positive electrode sheets and a plurality of negative electrode sheets in sequence, arranging a solid electrolyte between the positive electrode sheets and the negative electrode sheets, and then pressing them into a battery cell, and the positive electrode ears of the plurality of positive electrode sheets are stacked to form a positive electrode ear piece, and the negative electrode ears of the plurality of negative electrode sheets are stacked to form a negative electrode ear piece; a reinforcing layer is arranged on the outer side of the negative electrode ear piece and / or the positive electrode ear piece; and the positive electrode connector and the negative electrode connector are respectively connected to the positive electrode ear piece and the negative electrode ear piece to serve as the lead-out structure of the battery cell. In the actual processing process, the positive ear piece and the negative ear piece are subjected to secondary processing, and a conductive metal foil is fixed to the positive ear piece and / or the negative ear piece by bonding or pressing as a reinforcing layer 300. In the multi-layer positive ear, the inner positive ear is reinforced by the outer positive ear, and the outer positive ear is reinforced by the reinforcing layer 300; in the multi-layer negative ear, the inner negative ear is reinforced by the outer negative ear, and the outer negative ear is reinforced by the reinforcing layer 300, thereby improving the strength of the positive ear piece and the negative ear piece. Under higher pressure, the positive ear piece and the negative ear piece with greater strength shrink relatively less, and are not prone to shrinkage and brittleness, thereby avoiding the brittle fracture of the positive ear piece and the negative ear piece.

[0058] The function of the reinforcing layer 300 disclosed in the present invention is described in detail below with reference to the table.

[0059]

[0060] The ratio value is: the ratio of the size of the reinforcement layer 300 along the first direction to the size of the tab 200 along the first direction;

[0061] Tab 200 fracture rate = number of cells with tab 200 fractures in 100 cells / 100;

[0062] Tab 200 fracture rate test method: package the battery cell with a nylon bag and evacuate it, place the packaged battery cell in the isostatic pressing equipment cavity, apply pressure, and when the pressure reaches the set pressure value (the pressure value in this experiment is 600Mpa, of course, it can also be selected according to actual needs), maintain the pressure for 5-15 minutes, release the pressure and take out the battery cell to observe whether the tab 200 is broken.

[0063] The testing method of the effective welding area is as follows: the tab 200 is welded to the electrical connector, and then the tab 200 after welding is peeled off, and the residual area after peeling off / the preset welding area = the effective welding area.

[0064] According to Table 1, it can be seen from Examples 1-5 and Comparative Examples 1-3 that when the ratio value satisfies the range of 0.2-1.2, the fracture rate of the tab 200 is less than or equal to 5%, and the effective welding area is greater than 80%; in Comparative Examples 1-3, the ratio value in Comparative Example 1 is less than 0.2, the fracture rate of the tab 200 is greater than 50%, and the effective welding area is less than 80%; in Comparative Example 2, the ratio value is greater than 1.2, although the tab 200 does not break, the effective welding area is only 60%; in Comparative Example 3, the reinforcing layer 300 is not provided, the fracture rate of the tab 200 is as high as 92%, and due to the serious fracture of the tab 200, the effective welding area is only 20%. Therefore, according to Table 1, it can be explained that controlling the ratio of the size of the reinforcing layer 300 along the first direction to the size of the tab 200 along the first direction within the range of 0.2-1.2 can not only reduce the fracture rate of the tab 200, but also increase the effective welding area of ​​the tab 200.

[0065] In the description of this specification, the description with reference to the terms "some embodiments", "other embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0066] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A solid-state battery, characterized in that: The invention comprises a pole piece and a solid electrolyte, wherein the pole piece comprises a pole piece body (100) and a pole lug (200), wherein the surface of the pole lug (200) is coated with a reinforcing layer (300), and the reinforcing layer (300) at least covers the connection between the pole piece body (100) and the pole lug (200); wherein the ratio of the size of the reinforcing layer (300) along a first direction to the size of the pole lug (200) along the first direction is 0.2-1.2, and the first direction is the lead-out direction of the pole lug (200) relative to the pole piece body (100).

2. The solid-state battery according to claim 1, characterized in that: The first end of the reinforcement layer (300) along the first direction is arranged flush with the connection between the pole piece body (100) and the pole ear (200).

3. The solid-state battery according to claim 1, characterized in that: The second end of the reinforcement layer (300) along the first direction is aligned with the end of the pole ear (200) away from the pole piece body (100).

4. The solid-state battery according to claim 1, characterized in that: The thickness of the reinforcement layer (300) is 3 μm-100 μm; or: The ratio of the thickness of the reinforcement layer (300) to the thickness of the tab (200) is 0.1-15.

5. The solid-state battery according to claim 1, characterized in that: The pole pieces comprise a positive pole piece and a negative pole piece, the thickness of the reinforcing layer (300) on the positive pole ear of the positive pole piece is 3 μm-100 μm, and the thickness of the reinforcing layer (300) on the negative pole ear of the negative pole piece is 3 μm-50 μm.

6. The solid-state battery according to claim 5, characterized in that: The positive electrode sheet comprises a positive electrode current collector and a positive electrode active material layer. When the thickness of the positive electrode active material layer is greater than or equal to 240 μm, the thickness of the reinforcement layer (300) on the positive electrode tab is 10 μm-100 μm.

7. The solid-state battery according to claim 1, characterized in that: When the ratio of the thickness of the reinforcing layer (300) to the thickness of the pole tab (200) is less than 0.1, the ratio of the size of the reinforcing layer (300) along the first direction to the size of the pole tab (200) along the first direction is 0.3-1.

8. The solid-state battery according to claim 1, characterized in that: The pole piece body (100) comprises a current collector and an active material layer covering the current collector, the ratio of the thickness of the active material layer to the thickness of the current collector being greater than or equal to 10, wherein: The ratio of the size of the reinforcement layer (300) along the second direction to the size of the pole tab (200) along the second direction is in the range of 0.5-1; the second direction is arranged perpendicular to the first direction; The ratio of the size of the reinforcement layer (300) along the first direction to the size of the tab (200) along the first direction is 0.35-1.

2.

9. The solid-state battery according to any one of claims 1 to 8, characterized in that: The pole pieces include a positive pole piece and a negative pole piece, and an insulating layer (400) is also provided on the side of the reinforcing layer (300) disposed on the positive pole piece away from the pole lug (200).

10. The solid-state battery according to claim 9, characterized in that: The thickness of the insulating layer (400) is 3 μm-100 μm.

11. The solid-state battery according to claim 9, characterized in that: The size of the insulating layer (400) along the second direction is greater than or equal to the size of the reinforcing layer (300) along the second direction, and the second direction is arranged perpendicular to the first direction.

12. The solid-state battery according to claim 9, characterized in that: The size of the negative electrode sheet along the second direction is greater than the size of the positive electrode sheet along the second direction, and the difference between the size of the negative electrode sheet and the positive electrode sheet is set as a reference size, and the difference between the size of the insulating layer (400) along the second direction and the reference size is: 0.1mm-10mm; wherein: The second direction is arranged perpendicular to the first direction.

13. The solid-state battery according to claim 9, characterized in that: The insulating layer (400) comprises at least one of an insulating tape and an epoxy resin coating.

14. The solid-state battery according to any one of claims 1 to 8, characterized in that: The reinforcement layer (300) is made of conductive material.

15. The solid-state battery according to any one of claims 1 to 8, characterized in that: The reinforcing layer (300) is arranged around the circumference of the pole lug (200), and the reinforcing layer (300) has a head end and a tail end; the head end and the tail end have an overlapping area in a direction around the pole lug (200) or the head end and the tail end are connected; wherein: The ratio of the size of the reinforcement layer (300) along the first direction to the size of the tab (200) along the first direction is 0.25-1.

16. The solid-state battery according to any one of claims 1 to 8, characterized in that: An arc-shaped transition portion (500) is provided between the pole tab (200) and the pole piece body (100), and the ratio of the size of the reinforcement layer (300) along the first direction to the size of the pole tab (200) along the first direction is 0.2-1.

17. The solid-state battery according to claim 16, characterized in that: The reinforcement layer (300) is arranged to cover the arc-shaped transition portion (500).

18. The solid-state battery according to any one of claims 1 to 8, characterized in that: The pole piece comprises a plurality of pole piece bodies (100) which are stacked, and the reinforcing layer (300) is arranged on the pole lugs (200) located on the outside among the plurality of pole lugs (200).

19. A method for manufacturing a solid-state battery, characterized in that: The steps include: Forming reinforcement layers (300) on the positive electrode tab of the positive electrode sheet and the negative electrode tab of the negative electrode sheet respectively; The plurality of positive electrode sheets and the plurality of negative electrode sheets are stacked in sequence, a solid electrolyte is arranged between the positive electrode sheets and the negative electrode sheets, and then pressed into a battery cell, and the positive electrode ears of the plurality of positive electrode sheets are stacked to form a positive electrode ear piece, and the negative electrode ears of the plurality of negative electrode sheets are stacked to form a negative electrode ear piece; The positive electrode connector and the negative electrode connector are respectively connected to the positive electrode ear member and the negative electrode ear member to serve as the lead-out structure of the battery cell.

20. The method for manufacturing a solid-state battery according to claim 19, characterized in that: After the reinforcing layer (300) is wound around the positive electrode tab for at least one turn, the reinforcing layer (300) is covered with an insulating layer (400); or; At least one of the reinforcing layers (300) is respectively disposed on both sides of the positive electrode ear, and an insulating layer (400) is covered on the reinforcing layer (300).

21. A method for manufacturing a solid-state battery, characterized in that: The steps include: A plurality of positive electrode sheets and a plurality of negative electrode sheets are stacked in sequence, a solid electrolyte is arranged between the positive electrode sheets and the negative electrode sheets, and then pressed into a battery cell, and the positive electrode ears of the plurality of positive electrode sheets are stacked to form a positive electrode ear piece, and the negative electrode ears of the plurality of negative electrode sheets are stacked to form a negative electrode ear piece; Disposing a reinforcement layer (300) on the outer side of the negative electrode ear piece and / or the positive electrode ear piece; The positive electrode connector and the negative electrode connector are respectively connected to the positive electrode ear member and the negative electrode ear member to serve as the lead-out structure of the battery cell.

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