Pole piece structure of battery, battery and electric device

Abstract

The utility model belongs to the technical field of battery production and manufacturing, and particularly relates to a pole piece structure of a battery, the battery and an electric device. The first film surface is arranged on one surface of the current collector; the second film surface is arranged on the other surface of the current collector; a plurality of through holes are formed in the surface of the current collector, and at least one of the first film surface and the second film surface partially extends into the through holes, so that the first film surface is connected with the second film surface. By optimizing the pole piece structure, the lithium separation problem caused by the fact that the anode cannot be completely embedded into lithium ions of the cathode is solved.

Description

Technical Field

[0001] The utility model belongs to the technical field of battery production and manufacturing, and particularly relates to an electrode structure of a battery, a battery and an electrical device using the same. Background Art

[0002] Secondary batteries have the advantages of high energy density, high power density, high working voltage, light weight, small volume, long cycle life, good safety, environmental friendliness, etc., and have broad application prospects in portable electrical appliances, electric tools, large-scale energy storage, electric vehicle power sources, etc.

[0003] Among them, button batteries, also known as coin cells, have a relatively large diameter and a relatively small thickness. The CB values of the long film surface and the short film surface of the button cell core are inconsistent, and there is a difference of 0.001 - 0.100 between the CB value of the long film surface and the CB value of the short film surface.

[0004] In the process of implementing the present utility model, the inventors found that there are at least the following problems in the prior art

[0005] Since the button cell core is circular or oval, and there is a length difference between the inner circle and the outer circle of the electrode, it is easy to occur that the anode cannot fully embed the lithium ions in the cathode, resulting in easy lithium deposition in the inner circle of the button cell core, which has a great impact on the performance of the button cell core. Summary of the Utility Model

[0006] One of the purposes of the present utility model is to provide an electrode structure of a battery to solve the problem of lithium deposition caused by the anode not being able to fully embed the lithium ions in the cathode by optimizing the electrode structure in view of the deficiencies of the prior art.

[0007] To achieve the above purpose, the present utility model adopts the following technical solutions:

[0008] An electrode structure of a battery, comprising a current collector; a first film surface disposed on one side of the current collector; a second film surface disposed on the other side of the current collector; a plurality of through holes are provided on the surface of the current collector, and at least one of the first film surface and the second film surface partially extends into the through holes to connect the first film surface and the second film surface.

[0009] Preferably, the width of the through hole is d, 100μm ≤ d ≤ 1500μm, the thickness of the current collector is h, 2μm ≤ h ≤ 30μm, the thickness of the first film surface and the second film surface is h1, 50μm ≤ h1 ≤ 500μm, the depth of the through hole is d1, and the depth of the through hole and the thickness of the current collector satisfy the relationship: d1 = h.

[0010] Preferably, the length of the first film surface is L, and the distance between adjacent via holes is B. The distance between adjacent via holes and the length of the first film surface satisfy the relational expression: L / 30 ≤ B ≤ L / 5.

[0011] Preferably, the first film surface includes a first head and a first tail, which are respectively arranged at both ends of the first film surface in the length direction. A plurality of via holes enclose a punching area. The maximum distance between the first head of the first film surface and the edge of the punching area is L1, and it satisfies the relational expression with the length of the first film surface: 0 < L1 ≤ 0.25L.

[0012] Preferably, the difference between the length of the first film surface and the length of the second film surface is x, and it satisfies the relational expression: 0.25π*D ≤ x ≤ 0.5π*D, where D is the diameter of the battery cell.

[0013] Preferably, the second film surface includes a second head and a second tail, which are respectively arranged at both ends of the second film surface in the length direction. The projections of the first head and the second head in the thickness direction of the current collector are staggeredly arranged, and the projections of the first tail and the second tail in the thickness direction of the current collector overlap.

[0014] Preferably, a slurry is coated on a part of the surface of the current collector to form the first film surface or the second film surface. The length of the first film surface is less than the length of the second film surface, and the length of the second film surface is less than the length of the current collector.

[0015] Preferably, the via holes penetrate the current collector along the thickness direction of the current collector. The via holes are evenly spaced on the current collector, and the shape of the via holes is circular, square or oval.

[0016] The second object of the present invention is to provide a battery, including the electrode structure of the above battery.

[0017] The third object of the present invention is to provide an electrical device, including the above battery.

[0018] One of the above technical solutions has the following beneficial effects

[0019] The utility model optimizes the structure of the electrode sheet, punches one or more through holes in the current collector, and then coats the slurry on the current collector to form a first film surface and a second film surface respectively. When forming the first film surface by coating, the slurry of the first film surface enters the through holes, so that a part of the first film surface extends into the through holes, and a part of the first film surface extending into the through holes is in direct contact with the second film surface, realizing the conduction connection between the first film surface and the second film surface. When the number of lithium ions received by the first film surface is greater than its bearing capacity, the excess lithium ions can be transferred to the second film surface through the through holes for reception, enabling the anode to absorb more lithium ions, improving the lithium intercalation capacity of the anode, avoiding the lithium deposition problem caused by insufficient CB value of the battery cell, reducing the risk of low lithium deposition in the battery, and thus prolonging the service life of the button cell. Description of the Drawings

[0020] The features, advantages and technical effects of the exemplary embodiments of the present utility model will be described below with reference to the drawings.

[0021] Figure 1 It is a schematic cross-sectional structure diagram of the electrode sheet of the present utility model.

[0022] Figure 2 It is a schematic cross-sectional structure diagram of the battery of the present utility model.

[0023] Among them, the reference numerals are explained as follows:

[0024] 1 - Current collector; 11 - First film surface; 12 - Second film surface; 111 - First head; 112 - First tail; 121 - Second head; 122 - Second tail;

[0025] 2 - Through hole;

[0026] d - Width of the through hole; d1 - Depth of the through hole;

[0027] h - Thickness of the current collector; h1 - Thickness of the first film surface and the second film surface;

[0028] L - Length of the first film surface; B - Spacing between adjacent through holes;

[0029] L1 - Maximum distance between the first head of the first film surface and the edge of the punching area;

[0030] x - Difference between the length of the first film surface and the length of the second film surface;

[0031] a - Length direction; b - Thickness direction;

[0032] 31 - Aluminum foil; 32 - Positive electrode slurry;

[0033] 41 - Copper foil; 42 - Negative electrode slurry;

[0034] 5 - Positive electrode tab; 6 - Negative electrode tab;

[0035] 7 - Green glue. Specific embodiments

[0036] As used in the specification and claims, certain terms are used to refer to specific components. Those skilled in the art should understand that hardware manufacturers may use different terms to refer to the same component. The specification and claims do not use the difference in names as a way to distinguish components, but rather use the difference in functions of components as the criterion for distinction. As used throughout the specification and claims, the term "comprising" is an open - ended term and should be interpreted as "comprising but not limited to". "Substantially" means within an acceptable error range. Those skilled in the art can solve technical problems within a certain error range and basically achieve the technical effect.

[0037] In addition, terms such as "first", "second", etc. are used only for descriptive purposes and should not be construed as indicating or implying relative importance.

[0038] In the utility model, unless otherwise clearly specified and limited, terms such as "installed", "connected", "connected to", "fixed", etc. 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 directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the utility model can be understood according to specific circumstances.

[0039] The following further elaborates on the present utility model in conjunction with the accompanying drawings, but does not limit the present utility model.

[0040] Embodiment 1

[0041] Since the button cell is circular or oval, and there is a length difference between the inner and outer circles of the electrode sheet, it is easy for the anode to be unable to fully embed the lithium ions in the cathode, resulting in easy lithium deposition in the inner circle of the button cell, which has a great impact on the electrical performance of the button cell.

[0042] The electrode structure of the battery of the present utility model includes a current collector 1; a first film surface 11 disposed on one side of the current collector 1; a second film surface 12 disposed on the other side of the current collector 1; a plurality of via holes 2 are provided on the surface of the current collector 1, and at least one of the first film surface 11 and the second film surface 12 partially extends into the via holes 2 so that the first film surface 11 and the second film surface 12 are connected. By optimizing the electrode structure, the present utility model punches one or more via holes 2 in the current collector 1, and then coats the slurry on the current collector 1 to form the first film surface 11 and the second film surface 12 respectively. When the first film surface 11 is formed by coating, the slurry of the first film surface 11 enters the via holes 2, so that the first film surface 11 partially extends into the via holes 2. A part of the first film surface 11 extending into the via holes 2 is in direct contact with the second film surface 12, realizing the conduction connection between the first film surface 11 and the second film surface 12. When the amount of lithium ions received by the first film surface 11 is greater than its receiving capacity, the excess lithium ions can be transferred to the second film surface 12 through the via holes 2 for reception, enabling the anode to absorb more lithium ions, improving the lithium intercalation capacity of the anode, avoiding the problem of lithium deposition caused by insufficient CB value of the battery cell, reducing the risk of low lithium deposition in the battery, and thus extending the service life of the button cell.

[0043] It should be noted that in this embodiment, the length of the first film surface 11 is less than the length of the second film surface 12. The first film surface 11 can be understood as the short film surface, and the second film surface 12 can be understood as the long film surface. Generally, the current collector 1 is coated with the long film surface first and then the short film surface. The connecting material in the via holes 2 will be formed when the short film surface is coated, serving as a channel connecting the two sides of the current collector 1. However, the present utility model is not limited thereto. The connecting material in the via holes 2 can also be formed when the long film surface is coated, that is, the connecting material is the part of the second film surface 12 extending into the via holes 2. In some embodiments, it is formed when the long film surface and the short film surface are coated simultaneously, that is, the connecting material is the part of the first film surface 11 extending into the via holes 2 and the part of the second film surface 12 extending into the via holes 2, and the two parts are connected. Here, it is not limited. Among them, the current collector 1 is a foil material, and the part of the current collector 1 where the slurry is not coated is the empty foil. When the current collector 1 is wound, the tab is welded to the empty foil of the current collector 1, with the long film surface facing the inside of the battery cell and the short film surface facing the outside of the battery cell.

[0044] The CB value can be understood as the ratio of the anode capacity to the cathode capacity in the same stage. When the CB value is insufficient to a certain extent, the cathode cannot be fully utilized, and the anode cannot fully intercalate the lithium ions of the cathode, resulting in lithium deposition.

[0045] In the electrode sheet structure of the battery according to the present utility model, the width of the via hole 2 is d, where 100 μm ≤ d ≤ 1500 μm, the thickness of the current collector 1 is h, where 2 μm ≤ h ≤ 30 μm, and the thicknesses of the first film surface 11 and the second film surface 12 are h1, where 50 μm ≤ h1 ≤ 500 μm. For example, the width d of the via hole 2 is 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1000 μm, 1100 μm, 1200 μm, 1300 μm, 1400 μm, 1500 μm, etc., to prevent the via hole 2 from being too wide and affecting the overall mechanical strength of the current collector 1; the thickness h of the current collector 1 is 2 μm, 4 μm, 6 μm, 8 μm, 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm, 22 μm, 24 μm, 26 μm, 28 μm, 30 μm, etc., to prevent the current collector 1 from being too thick and causing an increase in production cost; the thickness h1 of the first film surface 11 and the second film surface 12 is 50 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm, 500 μm, etc., to prevent the thickness of the slurry coating from being too large and causing an increase in the production cost of the battery. In addition, the depth of the via hole 2 is d1, and the current collector 1 is a foil. If there is no difference in the thickness of the foil and the thickness of each region is h, then the depth of the via hole 2 and the thickness of the current collector 1 satisfy d1 = h, ensuring that the current collector 1 can be penetrated and the via hole 2 penetrates the current collector 1 along the thickness direction b of the current collector 1.

[0046] In the electrode sheet structure of the battery according to the present utility model, the length of the first film surface 11 is L, and the spacing between adjacent via holes 2 is B. The spacing between adjacent via holes 2 and the length of the first film surface 11 satisfy the relationship: L / 30 ≤ B ≤ L / 5. Specifically, adjacent via holes 2 are arranged at intervals, and the spacing between adjacent via holes 2 is the same. By limiting the spacing between adjacent via holes 2 in this embodiment, it is prevented that the spacing between adjacent via holes 2 is too large and affects the conduction effect of the first film surface 11 and the second film surface 12.

[0047] In the electrode structure of the battery according to the present utility model, the first film surface 11 includes a first head 111 and a first tail 112. The first head 111 and the first tail 112 are respectively arranged at both ends of the first film surface 11 in the length direction a. A plurality of via holes 2 enclose a punching area. The maximum distance from the first head 111 of the first film surface 11 to the edge of the punching area is L1, and it satisfies the relationship with the length of the first film surface 11: 0 < L1 ≤ 0.25L. In this embodiment, the cross-section of the current collector 1 has four via holes 2, and the via holes 2 are evenly spaced on the current collector 1. The four via holes 2 enclose a punching area. The via hole 2 close to the first head 111 is the first via hole, and so on. The via hole 2 close to the first tail 112 is the fourth via hole. The range of the punching area is approximately the distance between the edges of the first via hole and the fourth via hole. Among them, as shown in Figure 1 The maximum distance is L1. Starting from the first head 111 of the first film surface 11, it is the maximum distance to the edge of the punching area. It can also be understood as starting from the end face of the first head 111 to the edge of the fourth via hole.

[0048] In the electrode structure of the battery according to the present utility model, the difference in length between the first film surface 11 and the second film surface 12 is x, which satisfies the relationship: 0.25π*D ≤ x ≤ 0.5π*D, where D is the diameter of the battery cell. In this embodiment, the length of the first film surface 11 is the distance between the two end faces in the length direction a of the first film surface 11, and the length of the second film surface 12 is the distance between the two end faces in the length direction a of the second film surface 12. Limiting the difference in their lengths can prevent the difference in the lengths of the two faces from being too large and affecting the capacity of the electrode.

[0049] The working principle of the present utility model is:

[0050] The present utility model optimizes the electrode structure by punching one or more via holes 2 in the current collector 1, and then coating slurries on the current collector 1 to form the first film surface 11 and the second film surface 12 respectively. When coating to form the first film surface 11, the slurry of the first film surface 11 enters the via holes 2, so that a part of the first film surface 11 extends into the via holes 2. A part of the first film surface 11 extending into the via holes 2 is in direct contact with the second film surface 12, realizing the conductive connection between the first film surface 11 and the second film surface 12. When the first film surface 11 receives more lithium ions than its receiving capacity, the excess lithium ions can be transferred to the second film surface 12 through the via holes 2 for reception, enabling the anode to absorb more lithium ions, enhancing the lithium intercalation ability of the anode, avoiding the lithium precipitation problem caused by insufficient CB value of the battery cell, reducing the risk of low lithium precipitation in the battery, and thus extending the service life of the button battery cell.

[0051] Embodiment 2

[0052] Different from Embodiment 1: The second film surface 12 of this embodiment includes a second head 121 and a second tail 122. The second head 121 and the second tail 122 are respectively arranged at both ends of the second film surface 12 in the length direction a. The projections of the first head 111 and the second head 121 in the thickness direction b of the current collector 1 are staggeredly arranged, and the projections of the first tail 112 and the second tail 122 in the thickness direction b of the current collector 1 overlap. In this embodiment, the projections of the first tail 112 and the second tail 122 overlap, and the first head 111 and the second head 121 are staggeredly arranged. When the length of the first film surface 11 is less than the length of the second film surface 12, a welding space can be reserved at the empty foil on the side of the current collector 1 close to the first film surface 11, ensuring that the tab can be welded on the empty foil on the side of the current collector 1 close to the short film surface.

[0053] Other structures are the same as those in Embodiment 1 and will not be described in detail here.

[0054] Embodiment 3

[0055] Different from Embodiment 1: The surface of the current collector 1 in this embodiment is partially coated with slurry to form the first film surface 11 or the second film surface 12. Specifically, the pole piece is coated by a coater. First, one side of the current collector 1 is coated to form a long film surface, and then the other side of the current collector 1 is coated to form a short film surface. The length of the second film surface 12 is less than the length of the current collector 1. The shape of the via hole 2 includes but is not limited to circular, square or oval, and can also be other regular or irregular shapes, which are not limited here.

[0056] Other structures are the same as those in Embodiment 1 and will not be described in detail here.

[0057] Battery

[0058] The utility model includes the pole piece structures of the batteries in Embodiments 1 to 3.

[0059] Specifically, the battery includes a first pole piece, a separator, a second pole piece and an electrolyte. The first pole piece, the separator and the second pole piece are wound in sequence to form a bare battery cell. Tabs are welded on the first pole piece and the second pole piece respectively.

[0060] To avoid short circuit between the positive and negative pole pieces, a separator is arranged between every two adjacent pole pieces, and the pole pieces with opposite polarities are electrically isolated through the separator.

[0061] The first pole piece can be a positive pole piece (cathode piece) with a positive tab 5 welded thereon, and the second pole piece can be a negative pole piece (anode piece) with a negative tab 6 welded thereon. Green glue 7 is provided on both sides of the welding position; or, the first pole piece can be a negative pole piece (anode piece), and the second pole piece can be a positive pole piece (cathode piece), which is not limited here.

[0062] Among them, the negative electrode plate adopts the electrode plate structure of the present utility model. The negative electrode plate includes a copper foil 41. One side of the copper foil 41 is coated with a negative electrode paste 42 to form a short film surface, and the other side of the copper foil 41 is coated with the negative electrode paste 42 to form a long film surface. By setting a punching area on the surface of the copper foil 41 and punching holes, the short film surface and the long film surface are electrically connected through the via holes 2, increasing the fluidity inside the battery cell. The positive electrode plate includes an aluminum foil 31, and both sides of the aluminum foil 31 are coated with a positive electrode paste 32.

[0063] When the battery cell is charged and discharged, the positive electrode plate outputs lithium ions, and the negative electrode plate embeds lithium ions. When the lithium ions cannot be embedded by the negative electrode plate, lithium deposition will occur on the surfaces of the short film surface and the long film surface. However, in the present utility model, by punching holes in the copper foil 41, the short film surface and the long film surface are connected, which can increase the lithium embedding capacity of the negative electrode plate and reduce the risk of lithium deposition in the battery.

[0064] Power-consuming device

[0065] The battery containing the electrode plate structure of the present utility model can also be used in different power-consuming devices. The power-consuming devices can be automobiles, mobile phones, portable devices, laptop computers, ships, spacecrafts, electric toys, and electric tools, etc. The automobiles can be fuel vehicles, gas vehicles, or new energy vehicles. The new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc.; The spacecrafts include airplanes, rockets, space shuttles, and spaceships, etc.; The electric toys include fixed or mobile electric toys. For example, game consoles, electric vehicle toys, electric ship toys, and electric airplane toys, etc.; The electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools, and railway electric tools. For example, electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact electric drills, concrete vibrators, and electric planers, etc. The embodiments of the present application do not impose special restrictions on the above-mentioned power-consuming devices.

[0066] According to the disclosure and teachings of the above specification, those skilled in the art of the present utility model can also make changes and modifications to the above embodiments. Therefore, the present utility model is not limited to the above specific embodiments. Any obvious improvements, substitutions, or variations made by those skilled in the art based on the present utility model fall within the protection scope of the present utility model. In addition, although some specific terms are used in this specification, these terms are only for convenience of description and do not constitute any limitation to the present utility model.

Claims

1. A battery pole piece structure, characterized in that: include: current collector(1); A first membrane surface (11) is arranged on one side of the current collector (1); A second membrane surface (12) is arranged on the other side of the current collector (1); The surface of the current collector (1) is provided with a plurality of conducting holes (2), and at least one of the first membrane surface (11) and the second membrane surface (12) partially extends into the conducting hole (2), so that the first membrane surface (11) and the second membrane surface (12) are connected.

2. A battery pole piece structure as claimed in claim 1, characterized in that: The width of the conductive hole (2) is d, 100 μm≤d≤1500 μm, the thickness of the current collector (1) is h, 2 μm≤h≤30 μm, the thickness of the first membrane surface (11) and the second membrane surface (12) is h1, 50 μm≤h1≤500 μm, the depth of the conductive hole (2) is d1, and the depth of the conductive hole (2) and the thickness of the current collector (1) satisfy the relationship: d1=h.

3. A battery pole piece structure as claimed in claim 2, characterized in that: The length of the first membrane surface (11) is L, the spacing between adjacent conductive holes (2) is B, and the spacing between two adjacent conductive holes (2) and the length of the first membrane surface (11) satisfy the relationship: L / 30≤B≤L / 5.

4. A battery pole piece structure as claimed in claim 3, characterized in that: The first membrane surface (11) comprises a first head portion (111) and a first tail portion (112), wherein the first head portion (111) and the first tail portion (112) are respectively arranged at two ends of the length direction of the first membrane surface (11), and a plurality of conductive holes (2) form a perforated area. The maximum distance between the first head portion (111) of the first membrane surface (11) and the edge of the perforated area is L1, and the length of the first membrane surface (11) satisfies the relationship: 0<L1≤0.25L.

5. A battery pole piece structure according to any one of claims 1 to 4, characterized in that: The difference between the length of the first membrane surface (11) and the length of the second membrane surface (12) is x, which satisfies the relationship: 0.25π*D≤x≤0.5π*D, wherein D is the diameter of the battery cell.

6. A battery pole piece structure as claimed in claim 4, characterized in that: The second membrane surface (12) comprises a second head portion (121) and a second tail portion (122), the second head portion (121) and the second tail portion (122) being respectively arranged at two ends of the length direction of the second membrane surface (12), the projections of the first head portion (111) and the second head portion (121) in the thickness direction of the current collector (1) being staggered, and the projections of the first tail portion (112) and the second tail portion (122) in the thickness direction of the current collector (1) being overlapped.

7. A battery pole piece structure according to any one of claims 1 to 4, characterized in that: The surface of the current collector (1) is partially coated with slurry to form the first membrane surface (11) or the second membrane surface (12), the length of the first membrane surface (11) is smaller than the length of the second membrane surface (12), and the length of the second membrane surface (12) is smaller than the length of the current collector (1).

8. A battery pole piece structure according to any one of claims 1 to 4, characterized in that: The conducting holes (2) penetrate the current collector (1) along the thickness direction of the current collector (1), the conducting holes (2) are evenly spaced on the current collector (1), and the shape of the conducting holes (2) is circular, square or elliptical.

9. A battery, characterized in that: A battery pole piece structure comprising any one of claims 1 to 8.

10. An electrical device, characterized in that: A battery comprising the battery of claim 9.

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