Secondary battery and electric equipment

Abstract

The embodiment of the invention discloses a secondary battery and electric equipment. The secondary battery comprises a shell, a first electrode assembly and a second diaphragm, the shell comprises a shell body and a first active substance layer, the shell body is provided with an accommodating cavity and comprises a first sealing plate and a side wall, the side wall is wound on the first sealing plate, the first active substance layer is arranged on the surface, facing the accommodating cavity, of the first sealing plate, and the first sealing plate and the first active substance layer form a first edge electrode; the first electrode assembly comprises a first pole piece, a second pole piece and a first diaphragm, the first pole piece is electrically connected with the shell body, the second pole piece comprises a second sub-pole piece, and the second sub-pole piece is located on the outermost side in the thickness direction of the first electrode assembly in the first direction and stacked with the first edge electrode; along the first direction, the second diaphragm is arranged between the second sub-pole piece and the first edge electrode. According to the embodiment of the invention, the internal space of the secondary battery can be fully utilized, and the energy density of the secondary battery is improved.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of batteries, and in particular, to a secondary battery and an electrical device using the same. Background Art

[0002] A secondary battery refers to a battery that can restore electrical energy through charging and be reused, such as a lithium-ion battery, a nickel-metal hydride battery, or a lead-acid battery, etc. Secondary batteries are widely used in consumer electronic devices or energy storage devices, etc. At present, how to improve the energy density of secondary batteries has attracted the close attention of researchers. Summary of the Invention

[0003] The inventors of the present application have found through research that currently, the current collector on the outermost side of the electrode assembly of a secondary battery is only coated with active material on one side, failing to make full use of the internal space of the secondary battery and reducing the energy density of the secondary battery.

[0004] The embodiments of the present application aim to provide a secondary battery and an electrical device using the same, which can improve the energy density.

[0005] To solve the above technical problems, one technical solution adopted in the embodiments of the present application is: to provide a secondary battery, including a housing, a first electrode assembly, and a second separator; the housing includes a housing body and a first active material layer, the housing body is provided with a receiving cavity, the housing body includes a first sealing plate and a side wall, the side wall is wound around the first sealing plate, the first active material layer is provided on the surface of the first sealing plate facing the receiving cavity, and the first sealing plate and the first active material layer form a first edge electrode; the first electrode assembly includes a first electrode plate, a second electrode plate, and a first separator, the first electrode plate and the second electrode plate are alternately arranged in the receiving cavity, the first separator is arranged between adjacent first electrode plates and second electrode plates, the first electrode plate is electrically connected to the housing body, the second electrode plate includes a second sub-electrode plate, along a first direction, the second sub-electrode plate is located on the outermost side in the thickness direction of the first electrode assembly and is stacked with the first edge electrode; the first direction is the thickness direction of the first electrode assembly; along the first direction, the second separator is arranged between the second sub-electrode plate and the first edge electrode.

[0006] In the present application, the first sealing plate and the first active material layer of the housing body form a first edge electrode. Among them, the first edge electrode uses the first sealing plate of the housing body as the current collector of the first edge electrode, without introducing an additional current collector carrier as the current collector of the first edge electrode, which can make full use of the space of the receiving cavity of the housing body, that is, make full use of the internal space of the secondary battery and improve the energy density of the secondary battery.

[0007] In some embodiments, the outer casing includes a conductive layer, and the conductive layer includes a first conductive layer. Along a first direction, a first sealing plate, the first conductive layer, and a first active material layer are stacked, and the first conductive layer is disposed between the first sealing plate and the first active material layer. The conductivity of the first conductive layer is greater than that of the first sealing plate to improve the conductivity of the first edge electrode. By providing the first conductive layer, the conductivity of the first edge electrode can be improved.

[0008] In some embodiments, along the first direction, the thickness of the first conductive layer is H1, and H1 satisfies: H1 ≤ 100 um. By setting H1 ≤ 100 um, it is possible to prevent the first conductive layer from being too thick and reduce the energy density of the secondary battery.

[0009] In some embodiments, H1 satisfies: 0.1 um ≤ H1 ≤ 5 um. By setting 0.1 um ≤ H1, the risk of wear and failure of the first conductive layer during long-term use due to the first conductive layer being too thin can be reduced; by setting H1 ≤ 5 um, not only can the reduction of the energy density of the secondary battery caused by the first conductive layer being too thick be further avoided, but also the increase of the internal resistance and heat loss of the first conductive layer caused by the first conductive layer being too thick can be avoided.

[0010] In some embodiments, the shell body includes a second sealing plate, and a side wall is wound around the second sealing plate. The first sealing plate, the side wall, and the second sealing plate together form a receiving cavity. Along the first direction, the second sealing plate is disposed opposite to the first sealing plate; the outer casing further includes a second active material layer, and the second active material layer is disposed on the surface of the second sealing plate facing the receiving cavity. The second sealing plate and the second active material layer constitute a second edge electrode; the number of second sub-electrode plates is two. Along the first direction, the two second sub-electrode plates are respectively located on the outermost two sides in the thickness direction of the first electrode assembly and are respectively stacked with the first edge electrode and the second edge electrode; the secondary battery further includes a third separator. Along the first direction, the second separator is disposed between one second sub-electrode plate and the first edge electrode, and the third separator is disposed between the other second sub-electrode plate and the second edge electrode. Among them, the second edge electrode uses the second sealing plate of the shell body as the current collector of the second edge electrode, and there is no need to introduce an additional current collector carrier as the current collector of the second edge electrode, which can further utilize the space of the receiving cavity of the shell body, that is, further utilize the internal space of the secondary battery and further improve the energy density of the secondary battery.

[0011] In some embodiments, the polarity of the second edge electrode is the same as that of the first edge electrode. By setting the polarity of the second edge electrode to be the same as that of the first edge electrode, the materials of the first sealing plate and the second sealing plate of the shell body can be the same, simplifying the structure of the shell body.

[0012] In some embodiments, the outer casing includes a conductive layer, and the conductive layer includes a second conductive layer. Along the first direction, the second sealing plate, the second conductive layer, and the second active material layer are stacked, and the second conductive layer is disposed between the second sealing plate and the second active material layer. The conductivity of the second conductive layer is greater than that of the second sealing plate to improve the conductivity of the second edge electrode. By providing the second conductive layer, the conductivity of the second edge electrode can be improved.

[0013] In some embodiments, along the first direction, the thickness of the second conductive layer is defined as H2, and H2 satisfies: H2 ≤ 100 um. By setting H2 ≤ 100 um, it is possible to avoid a relatively thick second conductive layer and reduce the energy density of the secondary battery.

[0014] In some embodiments, H2 satisfies: 0.1 um ≤ H2 ≤ 5 um. By setting 0.1 um ≤ H2, the risk of wear and failure of the second conductive layer during long-term use due to a relatively thin second conductive layer can be reduced; by setting H2 ≤ 5 um, not only can the reduction of the energy density of the secondary battery caused by a relatively thick second conductive layer be further avoided, but also the increase in the internal resistance and heat loss of the second conductive layer caused by a relatively thick second conductive layer can be avoided.

[0015] In some embodiments, the first edge electrode is an anode. By setting the first edge electrode as an anode, the first sealing plate can be made of steel, so that the shell body corresponds to a steel shell, improving the structural strength of the secondary battery.

[0016] In some embodiments, the material of the conductive layer includes metals such as copper, silver, nickel, and titanium. By setting the material of the conductive layer as metals such as copper, silver, nickel, and titanium, the resistance of the conductive layer can be reduced, enabling the conductive layer to have good conductivity.

[0017] In some embodiments, the shell body further includes a conductive terminal, and the conductive terminal is disposed on the side wall and electrically connected to the first electrode plate. By disposing the conductive terminal on the side wall and leading out the polarity of the shell body from the side wall, the resistance of the current path can be minimized, improving the current transmission efficiency.

[0018] To solve the above technical problems, another technical solution adopted in the embodiments of the present application is: to provide an electrical device including the above secondary battery.

[0019] The beneficial effects of the embodiments of the present application are as follows: Different from the prior art, the secondary battery of the embodiments of the present application includes a housing, a first electrode assembly, and a second separator; the housing includes a housing body and a first active material layer, the housing body is provided with a receiving cavity, the housing body includes a first sealing plate and a side wall, the side wall is wound around the first sealing plate, the first active material layer is disposed on the surface of the first sealing plate facing the receiving cavity, and the first sealing plate and the first active material layer form a first edge electrode; the first electrode assembly includes a first electrode tab, a second electrode tab, and a first separator, the first electrode tab and the second electrode tab are alternately disposed in the receiving cavity, the first separator is disposed between the adjacent first electrode tab and the second electrode tab, the first electrode tab is electrically connected to the housing body, the second electrode tab includes a second sub-electrode tab, along a first direction, the second sub-electrode tab is located on the outermost side in the thickness direction of the first electrode assembly and is stacked with the first edge electrode; the first direction is the thickness direction of the first electrode assembly; along the first direction, the second separator is disposed between the second sub-electrode tab and the first edge electrode.

[0020] In the present application, the first sealing plate and the first active material layer of the housing body form the first edge electrode. Among them, the first edge electrode uses the first sealing plate of the housing body as the current collector of the first edge electrode, without introducing an additional current collector carrier as the current collector of the first edge electrode, and can make full use of the space of the receiving cavity of the housing body, that is, make full use of the internal space of the secondary battery, and improve the energy density of the secondary battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the specific embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. In all the drawings, similar elements or parts are generally denoted by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0022] Figure 1 is a schematic diagram of the overall structure of the secondary battery provided by the embodiments of the present application;

[0023] Figure 2 is a schematic diagram of a partial structure of the secondary battery provided by the embodiments of the present application Figure 1 ;

[0024] Figure 3 is a schematic diagram of a partial structure of the secondary battery provided by the embodiments of the present application Figure 2 ;

[0025] Figure 4 is a schematic diagram of a partial structure of the secondary battery provided by the embodiments of the present application Figure 3 ;

[0026] Figure 5 is a schematic diagram of the structure of an embodiment of the housing body of the secondary battery provided by the embodiments of the present application;

[0027] Figure 6 It is a schematic structural diagram of the first region and the second region of the first sealing plate of the secondary battery provided by the embodiment of the present application;

[0028] Figure 7 It is a schematic structural diagram of the third region and the fourth region of the second sealing plate of the secondary battery provided by the embodiment of the present application;

[0029] Figure 8 It is a schematic structural diagram of another embodiment of the housing body of the secondary battery provided by the embodiment of the present application.

[0030] Explanation of reference numerals:

[0031] 1 Outer shell, 11 Housing body, 111 Receiving cavity, 112 First sealing plate, 1121 First region, 1122 Second region, 113 Second sealing plate, 1131 Third region, 1132 Fourth region, 114 Side wall, 115 Bottom frame, 12 First active material layer, 13 Second active material layer;

[0032] 2 First electrode assembly, 21 First electrode tab, 22 Second electrode tab, 221 Second sub-electrode tab, 23 First separator;

[0033] 3 Second separator;

[0034] 4 Third separator;

[0035] 100 Secondary battery;

[0036] X First direction. Detailed implementation manners

[0037] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application.

[0038] Referring to "embodiment" in the present application means that the specific features, structures or characteristics described in connection with the embodiment may be included in at least one embodiment of the present application. The phrase appears in various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments.

[0039] In the description of the embodiments of the present application, technical terms such as "first" and "second" are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity, specific order or primary-secondary relationship of the indicated technical features. In the description of the embodiments of the present application, "a plurality of" means more than two, unless otherwise specifically defined.

[0040] In the description of the embodiments of the present application, the term "and / or" is merely a description of the association relationship between associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this article generally represents an "or" relationship between the preceding and following associated objects.

[0041] The term "vertical" is used to describe the ideal state between two components. In the actual production or use state, there can be a state approximately vertical between two components. For example, in combination with numerical descriptions, vertical can refer to the included angle range between two straight lines being between 90 ± 10°, vertical can also refer to the dihedral angle range between two planes being between 90 ± 10°, and vertical can also refer to the included angle range between a straight line and a plane being between 90 ± 10°. The two components described as "vertical" may not be absolute straight lines or planes, and can also be approximately straight lines or planes. From a macroscopic perspective, as long as the overall extension direction is a straight line or a plane, the components can be considered "straight lines" or "planes".

[0042] The first direction X, the second direction Y, and the third direction Z of the present application are two-way directions, that is, the first direction X includes the direction indicated by the arrow in the drawing and its opposite direction, the second direction Y includes the direction indicated by the arrow in the drawing and its opposite direction, and the third direction Z includes the direction indicated by the arrow in the drawing and its opposite direction.

[0043] Without conflict, the different embodiments of the present application described below and the technical features involved in the embodiments can be combined with each other.

[0044] A secondary battery refers to a battery that can restore electrical energy through charging and be reused, such as: lithium-ion batteries, nickel-metal hydride batteries, or lead-acid batteries, etc. Secondary batteries are widely used in consumer electronic devices or energy storage devices, etc. Currently, how to improve the energy density of secondary batteries is a problem closely concerned by researchers.

[0045] Based on this, the present application provides an embodiment of a secondary battery 100, which can improve the energy density of the secondary battery 100 and improve the energy storage capacity of the secondary battery 100.

[0046] To facilitate the reader's understanding of the concept of the embodiments of the present application, the following describes the specific structure of the secondary battery 100:

[0047] For the above-mentioned secondary battery 100, please refer to Figures 1 to 3, the secondary battery 100 includes a housing 1, a first electrode assembly 2, and a second separator 3; the housing 1 includes a housing body 11 and a first active material layer 12, the housing body 11 has electrical conductivity, the housing body 11 is provided with a receiving cavity 111, the housing body 11 includes a first sealing plate 112 and a side wall 114, the side wall 114 is wound around the first sealing plate 112, the first active material layer 12 is disposed on the surface of the first sealing plate 112 facing the receiving cavity 111, and the first sealing plate 112 and the first active material layer 12 constitute a first edge electrode; the first electrode assembly 2 includes a first electrode tab 21, a second electrode tab 22, and a first separator 23, the first electrode tab 21 and the second electrode tab 22 are alternately disposed in the receiving cavity 111, the first separator 23 is disposed between the adjacent first electrode tab 21 and the second electrode tab 22, the first electrode tab 21 is electrically connected to the housing body 11, the second electrode tab 22 includes a second sub-electrode tab 221, along the first direction X, the second sub-electrode tab 221 is located on the outermost side in the thickness direction of the first electrode assembly 2 and is stacked with the first edge electrode; the first direction X is the thickness direction of the first electrode assembly 2; along the first direction X, the second separator 3 is disposed between the second sub-electrode tab 221 and the first edge electrode.

[0048] In the present application, the first sealing plate 112 and the first active material layer 12 of the housing body 11 constitute the first edge electrode. Among them, the first edge electrode uses the first sealing plate 112 of the housing body 11 as the current collector of the first edge electrode, without introducing an additional current collector carrier as the current collector of the first edge electrode, and can make full use of the space of the receiving cavity 111 of the housing body 11, that is, make full use of the internal space of the secondary battery, and improve the energy density of the secondary battery.

[0049] In some embodiments, the first active material is disposed on the surface of the first sealing plate 112 facing the receiving cavity 111 by coating to form the first active material layer 12. It can be understood that the first active material includes, but is not limited to, being disposed on the surface of the first sealing plate 112 facing the receiving cavity 111 by coating to form the first active material layer 12. For example, in some other embodiments, the first active material is disposed on the surface of the first sealing plate 112 facing the receiving cavity 111 by spraying to form the first active material layer 12.

[0050] Please refer to Figure 3, the housing 1 includes a conductive layer, and the conductive layer includes a first conductive layer (not shown in the figure). Along the first direction X, the first sealing plate 112, the first conductive layer, and the first active material layer 12 are stacked. The first conductive layer is disposed between the first sealing plate 112 and the first active material layer 12, and the conductivity of the first conductive layer is greater than that of the first sealing plate 112. When the conductivity of the first sealing plate 112 is poor, in order to avoid large losses of current in the first edge electrode during the conduction process, by disposing the first conductive layer with a conductivity greater than that of the first sealing plate 112 between the first sealing plate 112 and the first active material layer 12, the conduction efficiency of the first edge electrode can be improved. In some embodiments, the material of the first sealing plate 112 is steel, and the material of the first conductive layer is copper. Among them, the conductivity of copper is greater than that of steel, so that the conductivity of the first conductive layer is greater than that of the first sealing plate 112.

[0051] In some embodiments, the first conductive material is disposed on the surface of the first sealing plate 112 facing the receiving cavity 111 by electroplating to form the first conductive layer. It can be understood that the first conductive material includes, but is not limited to, being disposed on the surface of the first sealing plate 112 facing the receiving cavity 111 by electroplating. For example, in some other embodiments, the first conductive material is disposed on the surface of the first sealing plate 112 facing the receiving cavity 111 by coating, physical vapor sputtering, chemical vapor deposition, or the like to form the first conductive layer.

[0052] In order to avoid conflicts between the formation of the first active material layer 12 and the formation of the first conductive layer, there are requirements for the sequence of the formation of the first active material layer 12 and the formation of the first conductive layer. In some embodiments, first, the first conductive material is disposed on the surface of the first sealing plate 112 facing the receiving cavity 111 by electroplating to form the first conductive layer, and then, the first active material is disposed on the surface of the first conductive layer facing the receiving cavity 111 by coating to form the first active material layer 12. By the above method, the formation of the first active material layer 12 and the formation of the first conductive layer can avoid conflicts.

[0053] Please refer to Figure 3, in order to enable the first conductive layer to play a good conductive role, there are requirements for the thickness of the first conductive layer. In some embodiments, along the first direction X, the thickness of the first conductive layer is H1, and H1 satisfies: H1 ≤ 100 um. Among them, setting H1 ≤ 100 um can avoid the reduction of the energy density of the secondary battery caused by the relatively thick first conductive layer. In order to avoid the increase of the internal resistance and thermal loss of the first conductive layer and the reduction of the energy seal of the secondary battery caused by the relatively large thickness of the first conductive layer, there are further requirements for the thickness of the first conductive layer. In other embodiments, H1 satisfies: 0.1 um ≤ H1 ≤ 5 um. Among them, setting 0.1 um ≤ H1 can reduce the risk of wear and failure of the first conductive layer during long-term use due to the relatively thin first conductive layer; setting H1 ≤ 5 um can not only further avoid the reduction of the energy density of the secondary battery caused by the relatively thick first conductive layer, but also avoid the increase of the internal resistance and thermal loss of the first conductive layer caused by the relatively thick first conductive layer. In some embodiments, H1 can be 0.1 um, 0.2 um, 0.3 um, 0.5 um, 0.7 um, 1 um, 2 um, 5 um, 10 um, 15 um, 20 um, 30 um, 40 um, 50 um, 60 um, 70 um, 80 um, 90 um, 100 um or a range composed of any two of these values.

[0054] For the above-mentioned case body 11, the case body 11 includes, in addition to the first sealing plate 112, other parts of the case body 11. The first sealing plate 112 and the other parts of the case body 11 jointly enclose to form the case body 11.

[0055] For the other parts of the above-mentioned case body 11, as an example, please refer to Figures 2 to 4 , please refer to together Figure 5 , the case body 11 includes a second sealing plate 113, a side wall 114 is wound around the second sealing plate 113, the first sealing plate 112, the side wall 114, and the second sealing plate 113 jointly form a receiving cavity 111. Along the first direction X, the second sealing plate 113 is disposed opposite to the first sealing plate 112; the outer shell 1 further includes a second active material layer 13, and the second active material layer 13 is disposed on the surface of the second sealing plate 113 facing the receiving cavity 111. The second sealing plate 113 and the second active material layer 13 constitute a second edge electrode; the number of the second sub-electrode plates 221 is two. Along the first direction X, the two second sub-electrode plates 221 are respectively located on the outermost two sides in the thickness direction of the first electrode assembly 2 and are respectively stacked with the first edge electrode and the second edge electrode; the secondary battery 100 further includes a third separator 4. Along the first direction X, the second separator 3 is disposed between one second sub-electrode plate 221 and the first edge electrode, and the third separator 4 is disposed between the other second sub-electrode plate 221 and the second edge electrode. Among them, the polarities of the first edge electrode and the second edge electrode are the same, which can simplify the structure of the case body and facilitate the manufacture of the case body.

[0056] The second sealing plate 113 of the housing body 11 and the second active material layer 13 in this application form a second edge electrode. Among them, the second edge electrode uses the second sealing plate 113 of the housing body 11 as the current collector of the second edge electrode, without introducing an additional current collector carrier as the current collector of the second edge electrode, and can further utilize the space of the accommodation cavity 111 of the housing body 11, that is, further utilize the internal space of the secondary battery, and further improve the energy density of the secondary battery.

[0057] In some embodiments, the second active material is disposed on the surface of the second sealing plate 113 facing the accommodation cavity 111 by coating to form the second active material layer 13. It can be understood that the second active material includes, but is not limited to, being disposed on the surface of the second sealing plate 113 facing the accommodation cavity 111 by coating to form the second active material layer 13. For example, in some other embodiments, the second active material is disposed on the surface of the second sealing plate 113 facing the accommodation cavity 111 by spraying to form the second active material layer 13.

[0058] Among them, when the second active material is disposed on the surface of the second sealing plate 113 facing the accommodation cavity 111 by coating to form the second active material layer 13, during the production process of a batch of the second active material layers 13, the second active material can be continuously coated on a batch of the second sealing plates 113 respectively to form a batch of the second active material layers 13, improving the production efficiency.

[0059] Please refer to Figure 3 , the outer shell 1 includes a conductive layer, and the conductive layer includes a second conductive layer (not shown in the figure). Along the first direction X, the second sealing plate 113, the second conductive layer, and the second active material layer 13 are stacked. The second conductive layer is disposed between the second sealing plate 113 and the second active material layer 13, and the conductivity of the second conductive layer is greater than that of the second sealing plate 113. When the conductivity of the first sealing plate 112 is poor, in order to avoid large losses of current in the second edge electrode during the conduction process, by disposing the second conductive layer with a conductivity greater than that of the second sealing plate 113 between the second sealing plate 113 and the second active material layer 13, the conduction efficiency of the second edge electrode can be improved. In some embodiments, the material of the second sealing plate 113 is steel, and the material of the second conductive layer is copper. Among them, the conductivity of copper is greater than that of steel, so that the conductivity of the second conductive layer is greater than that of the second sealing plate 113.

[0060] In some embodiments, the second conductive material is disposed on the surface of the second sealing plate 113 facing the receiving cavity 111 by electroplating to form a second conductive layer. It can be understood that the second conductive material includes, but is not limited to, being disposed on the surface of the second sealing plate 113 facing the receiving cavity 111 by electroplating. For example, in some other embodiments, the second conductive material is disposed on the surface of the second sealing plate 113 facing the receiving cavity 111 by coating, physical vapor sputtering, chemical vapor deposition, or the like to form a second conductive layer.

[0061] To avoid conflicts between the formation of the second active material layer 13 and the formation of the second conductive layer, there are requirements for the sequence of the formation of the second active material layer 13 and the formation of the second conductive layer. In some embodiments, first, the second conductive material is disposed on the surface of the second sealing plate 113 facing the receiving cavity 111 by electroplating to form a second conductive layer, and then, the second active material is disposed on the surface of the second conductive layer facing the receiving cavity 111 by coating to form the second active material layer 13. By the above method, the formation of the second active material layer 13 and the formation of the second conductive layer can avoid conflicts.

[0062] Please refer to Figure 3 , to enable the second conductive layer to play a good conductive role, there are requirements for the thickness of the second conductive layer. In some embodiments, along the first direction X, the thickness of the second conductive layer is H2, and H2 satisfies: H2 ≤ 100 um. Among them, setting H2 ≤ 100 um can avoid the reduction of the energy density of the secondary battery caused by the relatively thick second conductive layer. To avoid the increase in the internal resistance and heat loss of the second conductive layer and the reduction of the energy density of the secondary battery due to the relatively large thickness of the second conductive layer, there are further requirements for the thickness of the second conductive layer. In some other embodiments, H2 satisfies: 0.1 um ≤ H2 ≤ 5 um. Among them, setting 0.1 um ≤ H2 can reduce the risk of wear failure of the second conductive layer during long-term use due to the relatively thin second conductive layer; setting H2 ≤ 5 um can not only further avoid the reduction of the energy density of the secondary battery caused by the relatively thick second conductive layer, but also avoid the increase in the internal resistance and heat loss of the second conductive layer due to the relatively large thickness of the second conductive layer. In some embodiments, H2 can be 0.1 um, 0.2 um, 0.3 um, 0.5 um, 0.7 um, 1 um, 2 um, 5 um, 10 um, 15 um, 20 um, 30 um, 40 um, 50 um, 60 um, 70 um, 80 um, 90 um, 100 um or a range composed of any two of these values.

[0063] Please refer to Figure 6 and Figure 7, in some embodiments, the surface of the first sealing plate 112 facing the receiving cavity 111 is provided with a first region 1121 and a second region 1122. The second region 1122 is disposed around the edge of the first region 1121. The first region 1121 is used to dispose a first active material to form a first active material layer 12, and the second region 1122 is used to connect to the surface of one end of the side wall 114; the surface of the second sealing plate 113 facing the receiving cavity 111 is provided with a third region 1131 and a fourth region 1132. The fourth region 1132 is disposed around the edge of the third region 1131. The third region 1131 is used to dispose a second active material to form a second active material layer 13, and the fourth region 1132 is used to connect to the surface of the other end of the side wall 114.

[0064] Wherein, when the first active material is disposed in the first region 1121 by spraying, and the second active material is disposed in the third region 1131 by spraying, if the first active material extends beyond the first region 1121 to the second region 1122, and the second active material extends beyond the third region 1131 to the fourth region 1132, the first active material in the second region 1122 and the second active material in the fourth region 1132 can be removed by laser cleaning.

[0065] In some embodiments, the area of the first region 1121 is equal to the cross-sectional area of the first active material layer 12. The cross-section of the first active material layer 12 is the cross-section of the first active material layer 12 along the first direction X; the area of the third region 1131 is equal to the cross-sectional area of the second active material layer 13. The cross-section of the second active material layer 13 is the cross-section of the second active material layer 13 along the first direction X; the areas of the first region 1121 and the third region 1131 are both equal to the cross-sectional area of the receiving cavity 111. The cross-section of the receiving cavity 111 is the cross-section of the receiving cavity 111 along the first direction X. Among them, the "equal" in the above statement includes absolute equality in the ideal state, and approximate equality within the allowable error range. For example: "equal" can be understood as absolute equality, or "equal" can be understood as approximate equality that is more than ten percent or less than ten percent based on absolute equality.

[0066] To improve the sealing and conductivity of the housing body 11, there are requirements for the connection of the structure of the housing body 11. In some embodiments, the first sealing plate 112 is welded to one end of the side wall 114, and the second sealing plate 113 is welded to the other end of the side wall 114. The first sealing plate 112, the second sealing plate 113 and the side wall 114 together form the housing body 11. Among them, welding includes but is not limited to laser welding, ultrasonic welding, arc welding, spot welding or brazing, etc.

[0067] For other parts of the above housing body 11, as another example, please refer to Figures 2 to 4, and please refer to Figure 8 , the housing body 11 includes a second sealing plate 113. The second sealing plate 113 is integrally formed with the side wall 114 to form a bottom frame 115. The first sealing plate 112 and the bottom frame 115 together form a receiving cavity 111; the housing 1 further includes a second active material layer 13. The second active material layer 13 is disposed on the surface of the bottom of the bottom frame 115 facing the receiving cavity 111. The bottom of the bottom frame 115 and the second active material layer 13 constitute a second edge electrode; the secondary battery 100 further includes a third separator 4. The third separator 4 is disposed between the first electrode assembly 2 and the second edge electrode.

[0068] In some embodiments, the second active material is disposed on the surface of the bottom of the bottom frame 115 facing the receiving cavity 111 by coating to form the second active material layer 13. It can be understood that the second active material includes, but is not limited to, being disposed on the surface of the bottom of the bottom frame 115 facing the receiving cavity 111 by coating to form the second active material layer 13. For example, in some other embodiments, the second active material is disposed on the surface of the bottom of the bottom frame 115 facing the receiving cavity 111 by spraying to form the second active material layer 13.

[0069] In some embodiments, the second conductive material is disposed on the surface of the bottom of the bottom frame 115 facing the receiving cavity 111 by electroplating to form a second conductive layer. It can be understood that the second conductive material includes, but is not limited to, being disposed on the surface of the bottom of the bottom frame 115 facing the receiving cavity 111 by electroplating. For example, in some other embodiments, the second conductive material is disposed on the surface of the bottom of the bottom frame 115 facing the receiving cavity 111 by coating, physical vapor sputtering or chemical vapor deposition, etc. to form a second conductive layer.

[0070] To improve the sealing and conductivity of the housing body 11, requirements are imposed on the connection of the structure of the housing body 11. In some embodiments, one end of the first sealing plate 112 is welded to the bottom frame 115 so that the first sealing plate 112 and the bottom frame 115 together enclose to form the housing body 11, and one end of the first sealing plate 112 is electrically connected to the bottom frame 115. Compared with the first sealing plate 112, the second sealing plate 113 and the side wall 114 together enclosing to form the housing body 11, the above-mentioned first sealing plate 112 and the bottom frame 115 together enclosing to form the housing body 11 can reduce the number of welding times and the number of electrical connections.

[0071] In some embodiments, the first edge electrode is an anode. Setting the first edge electrode as an anode can enable the first sealing plate 112 to be made of steel, so that the housing body 11 corresponds to a steel shell, improving the structural strength of the secondary battery.

[0072] In some embodiments, both the first edge electrode and the second edge electrode are anodes. By setting both the first edge electrode and the second edge electrode as anodes, it is possible to make both the first sealing plate 112 and the second sealing plate 113 made of steel, or it is possible to make both the first sealing plate 112 and the bottom frame 115 made of steel, so that the housing body 11 corresponds to a steel shell, improving the structural strength of the secondary battery.

[0073] In some embodiments, the material of the conductive layer includes metals such as copper, silver, nickel, and titanium. By setting the material of the conductive layer as metals such as copper, silver, nickel, and titanium, the resistance of the conductive layer can be reduced, so that the conductive layer has good electrical conductivity. Among them, both the first conductive layer and the second conductive layer can be metals such as copper, silver, nickel, and titanium.

[0074] In some embodiments, the housing body 11 further includes a conductive terminal, the conductive terminal is disposed on the side wall 114, and the conductive terminal is electrically connected to the first electrode plate 21. By disposing the conductive terminal on the side wall 114 and leading out the polarity of the housing body 11 from the side wall 114, the resistance of the current path can be minimized, improving the current transmission efficiency.

[0075] The present application further provides an embodiment of an electrical device. The electrical device includes the above-mentioned secondary battery 100. For the specific structure and function of the above-mentioned secondary battery 100, reference can be made to the above embodiments, and details are not described herein again.

[0076] The secondary battery 100 according to an embodiment of the present application includes a housing 1, a first electrode assembly 2, and a second separator 3; the housing 1 includes a housing body 11 and a first active material layer 12, the housing body 11 is provided with a receiving cavity 111, the housing body 11 includes a first sealing plate 112 and a side wall 114, the side wall 114 is wound around the first sealing plate 112, the first active material layer 12 is disposed on the surface of the first sealing plate 112 facing the receiving cavity 111, and the first sealing plate 112 and the first active material layer 12 constitute a first edge electrode; the first electrode assembly 2 includes a first electrode tab 21, a second electrode tab 22, and a first separator 23, the first electrode tab 21 and the second electrode tab 22 are alternately disposed in the receiving cavity 111, the first separator 23 is disposed between the adjacent first electrode tab 21 and the second electrode tab 22, the first electrode tab 21 is electrically connected to the housing body 11, the second electrode tab 22 includes a second sub-electrode tab 221, along the first direction X, the second sub-electrode tab 221 is located on the outermost side in the thickness direction of the first electrode assembly 2 and is stacked with the first edge electrode; the first direction X is the thickness direction of the first electrode assembly 2; along the first direction X, the second separator 3 is disposed between the second sub-electrode tab 221 and the first edge electrode. In the present application, the first sealing plate 112 and the first active material layer 12 of the housing body 11 constitute the first edge electrode. Among them, the first edge electrode uses the first sealing plate 112 of the housing body 11 as the current collector of the first edge electrode, and there is no need to introduce an additional current collector carrier as the current collector of the first edge electrode, which can make full use of the space of the receiving cavity 111 of the housing body 11, that is, make full use of the internal space of the secondary battery and improve the energy density of the secondary battery.

[0077] The above are only the embodiments of the present application, and do not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present application, or directly or indirectly applied to other related technical fields, shall be equally included in the patent protection scope of the present application.

Claims

1. A secondary battery, characterized in that, Comprising: A casing, including a casing body and a first active material layer. The casing body is provided with a receiving cavity. The casing body includes a first sealing plate and a side wall. The side wall surrounds the first sealing plate. The first active material layer is disposed on the surface of the first sealing plate facing the receiving cavity. The first sealing plate and the first active material layer constitute a first edge electrode; A first electrode assembly, including a first pole piece, a second pole piece, and a first separator. The first pole piece and the second pole piece are alternately disposed in the receiving cavity. The first separator is disposed between the adjacent first pole piece and the second pole piece; the first pole piece is electrically connected to the casing body; The second pole piece includes a second sub-pole piece. Along a first direction, the second sub-pole piece is located on the outermost side in the thickness direction of the first electrode assembly and is stacked with the first edge electrode; the first direction is the thickness direction of the first electrode assembly; A second separator. Along the first direction, the second separator is disposed between the second sub-pole piece and the first edge electrode.

2. The secondary battery according to claim 1, wherein The casing includes a conductive layer. The conductive layer includes a first conductive layer. Along the first direction, the first sealing plate, the first conductive layer, and the first active material layer are stacked. The first conductive layer is disposed between the first sealing plate and the first active material layer. The conductivity of the first conductive layer is greater than the conductivity of the first sealing plate.

3. The secondary battery according to claim 2, wherein Along the first direction, the thickness of the first conductive layer is H1, and H1 satisfies: H1 ≤ 100um.

4. The secondary battery according to claim 3, wherein H1 satisfies: 0.1um ≤ H1 ≤ 5um.

5. The secondary battery according to claim 1, wherein The casing body includes a second sealing plate. The side wall surrounds the second sealing plate. The first sealing plate, the side wall, and the second sealing plate jointly form the receiving cavity. Along the first direction, the second sealing plate is disposed opposite to the first sealing plate; The casing further includes a second active material layer. The second active material layer is disposed on the surface of the second sealing plate facing the receiving cavity. The second sealing plate and the second active material layer constitute a second edge electrode; The number of the second sub-pole pieces is two. Along the first direction, the two second sub-pole pieces are respectively located on the outermost two sides in the thickness direction of the first electrode assembly and are respectively stacked with the first edge electrode and the second edge electrode; The secondary battery further includes a third separator. Along the first direction, the second separator is disposed between one of the second sub-pole pieces and the first edge electrode, and the third separator is disposed between the other second sub-pole piece and the second edge electrode.

6. The secondary battery according to claim 5, wherein The polarity of the second edge electrode is the same as the polarity of the first edge electrode.

7. The secondary battery according to claim 5, wherein The outer shell includes a conductive layer, and the conductive layer includes a second conductive layer. Along the first direction, the second sealing plate, the second conductive layer, and the second active material layer are stacked, the second conductive layer is disposed between the second sealing plate and the second active material layer, and the conductivity of the second conductive layer is greater than that of the second sealing plate.

8. The secondary battery according to claim 7, wherein Along the first direction, the thickness of the second conductive layer is H2, and H2 satisfies: H2 ≤ 100 um.

9. The secondary battery according to claim 8, characterized in that, H2 satisfies: 0.1 um ≤ H2 ≤ 5 um.

10. The secondary battery according to any one of claims 1-9, characterized in that, The first edge electrode is an anode.

11. The secondary battery according to claim 2 or 7, characterized in that, The material of the conductive layer includes metals such as copper, silver, nickel, and titanium.

12. The secondary battery according to claim 1, wherein the housing body further includes a conductive terminal, the conductive terminal is disposed on the side wall, and the conductive terminal is electrically connected to the first electrode plate.

13. An electrical device, characterized in that, A secondary battery including any one of claims 1-12.

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