Pole piece structure and battery

Abstract

The utility model belongs to the technical field of battery production and manufacturing, and particularly relates to a pole piece structure which comprises a current collector, the active material layer is arranged on the surface of the current collector; a plurality of stripes disposed on the surface of the active material layer; wherein at least part of the stripes are arranged in an inclined mode, and / or at least part of the stripes are arranged in a crossed mode. According to the utility model, by optimizing the surface structure of the pole piece, the lithium embedding tunnel can be increased under the condition of ensuring the laser ablation distance, and the charging performance of the battery can be improved.

Description

Technical Field

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

[0002] As a new type of secondary battery, lithium-ion batteries have the advantages of high energy density and power density, high working voltage, light weight, small size, long cycle life, good safety, and environmental friendliness, and have broad application prospects in portable electrical appliances, electric tools, large-scale energy storage, and electric vehicle power sources.

[0003] With the increasing charging rate and energy density of lithium-ion batteries, the negative electrode laser ablation technology is gradually used in the industry to improve the charging performance of thick electrodes.

[0004] In the process of implementing the present utility model, the inventor found that there are at least the following problems in the prior art: to obtain higher charging performance, more lithium insertion tunnels are required. The existing structure only increases the number of laser ablation lines by reducing the spacing, but too small a spacing will cause anode powder falling, resulting in insufficient anode CB and the risk of lithium plating. Summary of the Utility Model

[0005] One of the purposes of the present utility model is to provide an electrode structure, which can increase the lithium insertion tunnels while ensuring the laser ablation spacing by optimizing the surface structure of the electrode, thereby helping to improve the charging performance of the battery.

[0006] To achieve the above purpose, the present utility model adopts the following technical solutions:

[0007] An electrode structure includes a current collector; an active material layer disposed on the surface of the current collector; and a plurality of stripes disposed on the surface of the active material layer; wherein at least part of the stripes are inclined, and / or at least part of the stripes are crosswise arranged.

[0008] Preferably, at least part of the stripes crosswise enclose a rhombus.

[0009] Preferably, the spacing between two adjacent stripes is 2 mm - 4 mm.

[0010] Preferably, the ratio of the depth of the stripes to the thickness of the active material layer is 0.2 - 0.5.

[0011] Preferably, the depth of the stripes is 5 μm - 40 μm, and the cross-sectional width of the stripes is 10 μm - 100 μm.

[0012] Preferably, an angle α is formed between the stripes and the edge of the current collector, where 0° < α < 180°.

[0013] Preferably, the included angle α formed between the stripe and the edge of the current collector is 45°.

[0014] Preferably, the cross-sectional shape of the stripe is an arc-shaped concave structure.

[0015] Preferably, the area of the active material layer is smaller than the area of the current collector, and at least one end of the current collector is exposed on the surface of the electrode structure.

[0016] A second object of the present invention is to provide a battery including the above-mentioned electrode structure.

[0017] One of the above technical solutions has the following beneficial effects

[0018] By optimizing the surface structure of the electrode, the present invention changes the vertical stripes to oblique stripes, and the oblique stripes are cross-connected to each other, which can increase the total length of the stripes per unit area at the same stripe spacing, that is, on the premise of ensuring the intercalation lithium tunnel gap, by increasing the total length of the intercalation lithium tunnels on the electrode surface, it helps to improve the battery charging performance. At the same time, it prevents the anode powder from falling off due to too small a gap, resulting in insufficient CB of the anode, thereby improving the capacity margin of the negative electrode and reducing the risk of lithium deposition in the battery. Description of the Drawings

[0019] The features, advantages and technical effects of the exemplary embodiments of the present invention will be described below with reference to the drawings.

[0020] Figure 1 It is a schematic structural diagram of Embodiment 1 in the present invention.

[0021] Figure 2 It is a schematic cross-sectional diagram of Embodiment 1 in the present invention.

[0022] Figure 3 It is a schematic structural diagram of Embodiment 2 in the present invention.

[0023] Figure 4 It is a schematic structural diagram of Embodiment 3 in the present invention.

[0024] Among them, the reference numerals are explained as follows:

[0025] 1 - Current collector;

[0026] 2 - Active material layer;

[0027] 3 - Stripe. Specific Embodiments

[0028] 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 distinguish components by the difference in names, but by the difference in their functions. As used throughout the specification and claims, the term "comprising" is an open-ended term and should be interpreted as "including but not limited to". "Substantially" means within an acceptable error range, and those skilled in the art can solve technical problems within a certain error range and basically achieve the technical effect.

[0029] 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.

[0030] In a utility model, unless otherwise clearly specified and defined, terms such as "installed", "connected", "coupled", "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 elements. For those of ordinary skill in the art, the specific meanings of the above terms in this utility model can be understood according to specific circumstances.

[0031] The following further describes the present utility model in detail with reference to the accompanying drawings, but it is not a limitation to the present utility model.

[0032] Embodiment 1

[0033] Since more lithium-insertion tunnels need to be obtained to achieve higher charging performance, the existing structure only increases the number of laser ablation lines by reducing the spacing. However, if the spacing is too small, anode powder shedding will occur, resulting in insufficient anode CB and a risk of lithium plating.

[0034] The electrode sheet structure of the present utility model includes a current collector 1; an active material layer 2 provided on the surface of the current collector 1; and a plurality of stripes 3 provided on the surface of the active material layer 2. Among them, some of the stripes 3 are arranged crosswise. By optimizing the surface structure of the electrode sheet, the present utility model changes the vertical stripes to oblique stripes 3, and the oblique stripes 3 are cross-connected to each other. It can increase the total length of the stripes 3 per unit area at the same stripe 3 spacing, that is, on the premise of ensuring the gap of the lithium-insertion tunnels, by increasing the total length of the lithium-insertion tunnels on the surface of the electrode sheet, it helps to improve the battery charging performance. At the same time, it can prevent the situation that the gap is too small, resulting in anode powder shedding and insufficient anode CB, thereby improving the capacity margin of the negative electrode and reducing the risk of lithium plating in the battery.

[0035] In the pole piece structure according to the present utility model, the ratio of the depth of the stripe 3 to the thickness of the active material layer 2 is 0.2 - 0.5. For example, the ratio of the depth of the stripe 3 to the thickness of the active material layer 2 can be 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, etc., to prevent the depth of the stripe 3 from being too large, resulting in a reduction in the thickness of the active material layer 2 and affecting the energy density of the battery. Among them, the depth of the stripe 3 is preferably 5μm - 40μm. For example, the depth of the stripe 3 is preferably 5μm, 10μm, 15μm, 20μm, 25μm, 30μm, 35μm or 40μm, etc., but the present utility model is not limited thereto and can be adjusted according to the actual size of the pole piece.

[0036] In the pole piece structure according to the present utility model, the cross-sectional width of the stripe 3 is 10μm - 100μm. For example, the cross-sectional width of the stripe 3 is 10μm, 20μm, 30μm, 40μm, 50μm, 60μm, 70μm, 80μm, 90μm or 100μm, etc., to prevent the cross-sectional width of the stripe 3 from being too large, affecting the overall coating amount of the active material layer 2 and the energy density of the battery. However, the present utility model is not limited thereto and can be adjusted according to the actual size of the pole piece.

[0037] It should be noted that: the pole piece structure of the present utility model can be applied to the negative electrode of the battery. Using a laser ablation device, laser ablation is performed on the surface of the negative electrode to form a plurality of stripes 3 on the surface of the pole piece. The stripes 3 are punched with left-right intersections, and the plurality of stripes 3 enclose a diamond structure. In some embodiments, it can be understood that some of the stripes 3 intersect to form a network structure, and the shape of the mesh holes of the network structure is diamond-shaped, square, polygonal, or other regular shapes, which are not limited here. Among them, the cross-sectional shape of the stripe 3 is an arc-shaped concave structure and extends along a preset direction. The concave structure includes but is not limited to an arc shape. In some embodiments, it can also be one of a U shape, a semi-circular shape, and a square shape, or other regular or irregular shapes, which are not limited here, as long as the requirements of the lithium insertion tunnel are met.

[0038] In addition, the present utility model characterizes the charging ability of the present utility model through the ablation line-to-surface ratio P;

[0039] The ablation line-to-surface ratio P = L / S, where L is the laser ablation length and S is the area of the pole piece.

[0040] Specifically, the distance between two adjacent stripes 3 is 2mm, the width of the pole piece is 80mm, the length of the pole piece is 1000mm, and the included angle α formed between the stripe 3 and the edge of the current collector 1 is 45°;

[0041] The number of stripes 3 located at the edge of the electrode tab is 80 / 2 - 1 = 39. The length of stripe 3 located at the edge of the electrode tab is 80 / cos45° = 94 mm. The total length of stripe 3 located at the edge of the electrode tab is 39 * 94 = 3666 mm;

[0042] The number of stripes 3 located in the middle of the electrode tab is (1000 - 80) / 2 - 1 = 459. The length of stripe 3 located in the middle of the electrode tab is 80 / cos45° = 94 mm. The total length of stripe 3 located in the middle of the electrode tab is 459 * 94 = 43146 mm;

[0043] The laser ablation length L of this embodiment is (3666 + 43146) * 2 = 93624 mm. The area S of the electrode tab is 80 * 1000 mm = 800000 mm². Therefore, the ablation line-to-surface ratio P1 of this embodiment is 1.17 mm -1 。

[0044] Embodiment 2

[0045] The difference from Embodiment 1 is that all or part of the stripes 3 in this embodiment can be inclined in the same or different directions. This structure can also increase the total length of the lithium intercalation tunnels on the surface of the electrode tab, which helps to improve the battery charging performance. An angle α is formed between stripe 3 and the edge of the current collector 1, where 0° < α < 180°. The angles α formed between different stripes 3 and the edge of the current collector 1 can be the same or different, and are not limited here.

[0046] Other structures are the same as those in Embodiment 1 and will not be elaborated here.

[0047] Embodiment 3

[0048] The difference from Embodiment 1 is that part of the stripes 3 in this embodiment are inclined and part of the stripes 3 are crossed. This structure can also increase the total length of the lithium intercalation tunnels on the surface of the electrode tab, which helps to improve the battery charging performance. The area of the active material layer 2 is smaller than the area of the current collector 1, and at least one end of the current collector 1 is exposed on the surface of the electrode tab structure. Specifically, the electrode tab includes a current collector 1 and an active material layer 2 coated on the surface of the current collector 1. The surface of the electrode tab has an empty foil area, and the thickness of the empty foil area is smaller than that of the normal area in the middle. Among them, the current collector 1 is exposed on the surface of the empty foil area of the electrode tab, and the empty foil area is at both ends or in the middle of the electrode tab. The tab welding position is set in the empty foil area. It can be understood that the tab can be set at the head of the electrode tab, but the present invention is not limited thereto. The tab welding position can also be set in the coating area, which can be understood as the tab being set in the middle of the electrode tab. In addition, the tabs can also be set at the head and in the middle of the electrode tab respectively. The position and number of the tab welding positions are not limited here.

[0049] Embodiment 4

[0050] Differences from Example 1: The distance between two adjacent stripes 3 in this example is 4 mm, which can be adjusted according to the actual size of the electrode. The distance between two adjacent stripes 3 is expanded to 4 mm, and no specific limitation is set here.

[0051] Other structures are the same as those in Example 1 and will not be elaborated here.

[0052] Comparative Example 1

[0053] Differences from Example 1: The stripes in this comparative example are vertical structures, and laser ablation is carried out along the width direction of the electrode to form multiple parallel vertical stripes. The gap between the vertical stripes is 2 mm, the width of the electrode is 80 mm, the length of the electrode is 1000 mm, the number of stripes = 1000 / 2 - 1 = 499, and the ablation length

[0054] = 499 * 80 = 39920 mm. According to the ablation line area ratio P = L / S, the ablation line area ratio of this comparative example is

[0055] P2 = 39920 / 80 / 1000 = 0.499 mm -1 .

[0056] Comparing the ablation line area ratio P1 of Example 1 and the ablation line area ratio P2 of Comparative Example 1, P1 / P2 = 2.34. It can be concluded that under the same stripe distance, the ablation length per unit area of the stripe 3 in the electrode structure of Example 1 is 2.34 times that of the vertical ablation. The ablation length per unit area of the electrode structure in Example 1 exceeds the vertical ablation of Comparative Example 1. That is, on the premise of ensuring the intercalation lithium tunnel gap, by increasing the total length of the intercalation lithium tunnels on the electrode surface, it helps to improve the charging performance of the battery. In addition, since both the rhombus and the vertical shape are evenly distributed on the plane, the larger the ablation length per unit area of the electrode structure of the present invention, the better the quality of the battery.

[0057] The working principle of the present invention is:

[0058] By optimizing the electrode surface structure, the present invention changes the vertical stripes to oblique stripes 3, and the oblique stripes 3 are cross-connected with each other, which can increase the total length of the stripes 3 per unit area under the same stripe 3 distance. That is, on the premise of ensuring the intercalation lithium tunnel gap, by increasing the total length of the intercalation lithium tunnels on the electrode surface, it helps to improve the battery charging performance. At the same time, it prevents the anode powder falling due to too small a gap, resulting in insufficient CB of the anode, thereby improving the capacity margin of the negative electrode and reducing the risk of lithium deposition in the battery.

[0059] Battery

[0060] The battery of the present invention includes the electrode structures of Examples 1 to 4.

[0061] The battery includes a first electrode sheet, a separator, and a second electrode sheet. The first electrode sheet, the separator, and the second electrode sheet are wound in sequence to form a bare battery cell, and at least one of the first electrode sheet and the second electrode sheet adopts the above structure.

[0062] The battery is encapsulated with an aluminum-plastic film or a metal shell, and it can also be a packaging shell or a packaging bag made of other materials, which is not limited here.

[0063] The battery may include at least two electrode sheets stacked on each other and having opposite polarities. The electrode sheets with opposite polarities are the positive electrode sheet and the negative electrode sheet of the battery respectively. To avoid short circuit between the positive and negative electrode sheets, a separator is provided between every two adjacent electrode sheets, and the electrode sheets with opposite polarities are electrically isolated through the separator.

[0064] To avoid short circuit between the positive and negative electrode sheets, the electrode sheets with opposite polarities are electrically isolated through the separator. The first electrode sheet and the second electrode sheet have opposite polarities and are stacked on each other.

[0065] The first electrode sheet can be a positive electrode sheet, and the second electrode sheet can be a negative electrode sheet; or the first electrode sheet can be a negative electrode sheet, and the second electrode sheet can be a positive electrode sheet, which is not limited here.

[0066] In addition, the battery containing the electrode sheet structure of the present invention can also be used in electrical devices. The electrical devices can be automobiles, mobile phones, portable devices, laptop computers, ships, spacecrafts, electric toys, and electric tools, etc. The automobile can be a fuel vehicle, a gas vehicle, or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid electric vehicle, or an extended-range electric vehicle, etc.; the spacecraft includes 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. This application does not impose special restrictions on the above electrical devices.

[0067] According to the disclosure and teachings of the above specification, those skilled in the art of the present invention can also make changes and modifications to the above embodiments. Therefore, the present invention 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 invention fall within the protection scope of the present invention. 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 invention.

Claims

1. A pole piece structure, characterized in that, Comprising: Current collector (1); Active material layer (2), disposed on the surface of the current collector (1); Multiple stripes (3), disposed on the surface of the active material layer (2); Wherein, at least part of the stripes (3) are inclined, and / or at least part of the stripes (3) are cross - arranged.

2. The kind of pole piece structure described in claim 1, characterized in that: At least part of the stripes (3) cross - enclose a rhombus.

3. The tab structure according to claim 2, characterized in that: The distance between two adjacent stripes (3) is 2 mm - 4 mm.

4. A pole piece structure according to any one of claims 1-3, characterized in that: The ratio of the depth of the stripes (3) to the thickness of the active material layer (2) is 0.2 - 0.

5.

5. A pole piece structure according to any one of claims 1-3, characterized in that: The depth of the stripes (3) is 5 μm - 40 μm, and the cross - sectional width of the stripes (3) is 10 μm - 100 μm.

6. A pole piece structure according to any one of claims 1-3, characterized in that: An angle α is formed between the stripes (3) and the edge of the current collector (1), 0° < α < 180°.

7. The tab structure according to claim 6, characterized in that: The angle α formed between the stripes (3) and the edge of the current collector (1) is 45°.

8. A pole piece structure according to any one of claims 1-3, characterized in that: The cross - sectional shape of the stripes (3) is an arc - shaped concave structure.

9. A pole piece structure according to any one of claims 1-3, characterized in that: The area of the active material layer (2) is smaller than the area of the current collector (1), and at least one end of the current collector (1) is exposed on the surface of the electrode structure.

10. A battery, characterized in that: Comprising the electrode structure according to any one of claims 1 - 9.

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