Electrode assembly, battery and electric device

Abstract

The utility model provides an electrode assembly, a battery and a power utilization device, the electrode assembly comprises a pole piece and a diaphragm, the electrode assembly is formed by winding the pole piece and the diaphragm along one direction after the pole piece and the diaphragm are laminated, and a plurality of electrode layers are formed along the radial direction of the electrode assembly after the electrode assembly is wound. Each electrode layer comprises a tab and a coating area coated with an active material, a plurality of conducting strips are arranged between the tabs of the two adjacent electrode layers at intervals in the circumferential direction, each conducting strip is in contact with and electrically connected with the tabs on the two sides, and the conducting strips of each layer have overlapped partial projections in the radial direction of the electrode assembly. According to the electrode assembly, the battery and the electric device disclosed by the utility model, the welding of the tab and the corresponding part can be realized without shaping the tab, so that the short circuit risk caused by the fact that the tab is broken to generate metal slag in the shaping process and the metal slag falls into the battery cell is avoided; in addition, the thickness of a welding area is consistent, the welding explosion point / diaphragm scalding risk is reduced, and the process stability is improved.

Description

Technical Field

[0001] The utility model relates to the field of batteries, and in particular to an electrode assembly, a battery and an electrical device. Background Art

[0002] The advantages of high-energy-density battery structures have become a design solution adopted by major automotive OEMs. Based on market demand, new energy batteries are competing on the basis of long battery life and fast charging capabilities. Simplifying cylindrical structures and improving welding current capacity are the directions for continuous product improvement. Currently, there are two main methods for shaping cylindrical battery tabs on the market: full-tab flattening and multi-tab flattening. Both methods cause metal shavings to enter the battery due to external pressure and friction, which cannot be removed. This can easily cause battery self-discharge, posing a safety hazard. Furthermore, gaps between tab layers exist, and uneven and unstable voids remain within the flattened surface after pressure. This can lead to unstable weld connections, uneven current density, or even cold welds. Furthermore, these two methods result in different overlap thicknesses between tabs in different areas, resulting in differences in tab thickness at different weld mark locations, increasing the risk of weld explosions and diaphragm burns. In addition, since the material of the tab is relatively thin, when the tabs are bent one by one, the uneven external force causes the edge of the tab to easily bend into the inside of the pole piece, causing a short circuit in the battery, and it is impossible to form a good plane. The internal space is uneven, and the busbar needs to be relied upon for welding pressure and stress adjustment, which can easily lead to poor welding.

[0003] In view of this, it is necessary to improve the existing electrode assembly to solve the above problems. Utility Model Content

[0004] The purpose of the utility model is to provide an electrode assembly to solve the problem that the existing welding connection is unstable or easily causes a short circuit.

[0005] To achieve the above-mentioned purpose, the electrode assembly of the present invention includes a pole piece and a diaphragm, and the electrode assembly is formed by stacking the pole piece and the diaphragm and winding them in one direction. After the electrode assembly is wound, a multi-layer electrode layer is formed along its radial direction. Each electrode layer includes a pole ear and a coating area coated with an active material. A plurality of conductive sheets are arranged circumferentially between the pole ears of two adjacent electrode layers. Each conductive sheet is in contact with and electrically connected to the pole ears on both sides. Along the radial direction of the electrode assembly, there is a projection of overlapping portions of the conductive sheets of each layer.

[0006] As a further improvement of the present invention, the symmetry planes of adjacent conductive sheets between adjacent electrode layers overlap.

[0007] As a further improvement of the present invention, at least one side of adjacent conductive sheets between adjacent electrode layers are coplanar.

[0008] As a further improvement of the present invention, each electrode layer has the same number of conductive sheets, and each electrode layer has three to six conductive sheets.

[0009] As a further improvement of the present invention, the electrode assembly has a conductive area composed of adjacent conductive sheets and tabs, and a welding area for welding, and the axial projection of the welding area is located within the conductive area.

[0010] As a further improvement of the present invention, the thickness of the conductive sheet is greater than the distance between the two adjacent layers of the pole ears; and / or the height difference between the end of the conductive sheet away from the coating area and the end of the pole ear away from the coating area is greater than or equal to 0 and less than or equal to 1 mm.

[0011] As a further improvement of the present invention, one side of the conductive sheet is welded to the pole tab, and the other side of the conductive sheet is provided with conductive glue to bond with the adjacent pole tab; and / or, the conductive sheet and the pole sheet are made of the same material.

[0012] The present invention also provides a battery, which includes the electrode assembly as described above, a battery shell for accommodating the electrode assembly, and a current collector, wherein the conductive sheet of the electrode assembly is welded to one of the battery shell and the current collector.

[0013] As a further improvement of the present invention, each electrode layer is provided with pole ears at both ends along the axial direction, one end is a positive pole ear, and the other end is a negative pole ear. The positive pole ear and the negative pole ear are correspondingly provided with conductive sheets between the electrode layers. The positive pole ear is welded and fixed to the current collector, and the negative pole ear is welded and fixed to the bottom of the battery shell.

[0014] The utility model also provides an electrical device, which includes the battery as described above.

[0015] The beneficial effects of the present invention are as follows: the electrode assembly, battery and electrical device of the present invention can realize welding of the pole ear and the corresponding component without shaping the pole ear, thereby avoiding the pole ear breaking and generating metal slag during the shaping process, which falls into the battery cell and causes the risk of short circuit; in addition, the thickness of the welding area is ensured to be consistent, the risk of welding explosion point / diaphragm burns is reduced, and the process stability is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0017] Figure 1 This is a schematic diagram of the front structure of the battery of the present utility model;

[0018] Figure 2 This is a front structural diagram of the electrode assembly of the present utility model;

[0019] Figure 3 It is a schematic diagram of the top view of the electrode assembly of the present invention.

[0020] Figure numerals: 100, battery; 1, electrode assembly; 11, pole piece; 12, diaphragm; 13, electrode layer; 131, coating area; 132, pole ear; 133, conductive sheet; 2, battery case; 3, current collecting member; 4, welding wire. DETAILED DESCRIPTION

[0021] The following is a clear and complete description of the technical solution of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0022] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating positions or relationships, are based on the positions or relationships shown in the accompanying drawings and are intended solely to facilitate the description of this utility model and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0023] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be internal communication between two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0024] The pole piece includes a current collector (usually a metal foil), and the surface of the current collector has a coated area and a non-coated area. The coated area is used to coat the active material layer, and the non-coated area is used as a pole ear, which is the current output port of the current collector. Since there is no active material layer coated on the pole ear, when the pole piece is wound to form a battery cell, there is a gap between the pole ears of each layer of pole pieces. Therefore, the pole ear cannot usually be directly welded, but needs to be shaped first, for example, by kneading or flattening, so that each pole ear is bent toward the end face of the battery cell, so that each pole ear "lies" on the end face of the battery cell. However, the existing kneading and flattening methods have the technical problems described in the background technology. The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

[0025] like Figures 1 to 3 As shown, the electrical device of the present invention includes a battery 100 , and the battery 100 includes an electrode assembly 1 , a battery housing 2 for accommodating the electrode assembly 1 , and a current collector 3 .

[0026] like Figure 2 and Figure 3 As shown, the electrode assembly 1 includes a pole piece 11 and a separator 12. The electrode assembly 1 is formed by stacking the pole piece 11 and the separator 12 and winding them in one direction. After the electrode assembly 1 is wound, a multi-layer electrode layer 13 is formed along its radial direction.

[0027] The electrode assembly 1 has a conductive area composed of adjacent conductive sheets 133 and tabs 132 and a welding area for welding. The projection of the welding area along the axial direction is located within the conductive area.

[0028] Each electrode layer 13 includes a pole ear 132 and a coating area 131 coated with active material. A plurality of conductive sheets 133 are arranged circumferentially between the pole ears 132 of two adjacent electrode layers 13. Each conductive sheet 133 is in contact with and electrically connected to the pole ears 132 on both sides. Along the radial direction of the electrode assembly 1, there is a projection of overlapping portions of the conductive sheets 133 of each layer. Such an arrangement allows the overlapping portions along the radial direction to be welded.

[0029] Each electrode layer 13 has the same number of conductive sheets 133, which are spaced circumferentially. Optionally, each electrode layer 13 has three to six conductive sheets 133. In this embodiment, three conductive sheets 133 are provided on each layer. Thus, the welding area for welding is formed by the conductive sheets 133 between different electrode layers 13. The corresponding three welding areas are arranged in an array along the circumferential direction, improving the welding effect and avoiding the problem of uneven force on the electrode assembly 1.

[0030] The symmetry planes of adjacent conductive sheets 133 between adjacent electrode layers 13 coincide. Furthermore, at least one side of adjacent conductive sheets 133 between adjacent electrode layers 13 is coplanar. In this embodiment, both sides of adjacent conductive sheets 133 between adjacent electrode layers 13 are coplanar, resulting in a fan-shaped weld area. The weld wires 4 extend radially, and each weld area corresponds to multiple weld wires 4, which are also distributed in a fan-shaped pattern. This improves the utilization of the conductive sheets 133.

[0031] The length l0 of the conductive sheet 133 satisfies l0>n*(l 焊线 +l 热影响 ), n is the number of welding wires 4 in the same welding area, l 焊线 is the width of a single welding line 4, l 热影响 is the width of the heat-affected zone of a single welding line 4.

[0032] In this embodiment, the thickness of the conductive sheet 133 is greater than the distance between two adjacent layers of pole tabs 132. Furthermore, by setting the difference between the thickness of the conductive sheet 133 and the distance between two adjacent layers of pole tabs 132 to be greater than 0 mm and less than or equal to 2 mm, the conductive sheet 133 is slightly larger than the distance between two adjacent layers of pole tabs 132, so as to ensure that there is no gap between the pole tabs 132 on both sides of the conductive sheet 133, which is conducive to the subsequent direct welding of the pole tabs 132 and the corresponding components.

[0033] The height S of the conductive sheet 133 is less than l 极耳 , l 极耳 is the height of the tab 132. Furthermore, in this embodiment, the height difference between the end of the conductive sheet 133 away from the coating area 131 and the end of the tab 132 away from the coating area 131 is greater than or equal to 0 and less than or equal to 1 mm, with the optimal height difference being 0 mm. That is, the end of the conductive sheet 133 can be slightly lower than the end of the tab 132, or slightly higher than the end of the tab 132, but should not be too high or too low. If the height difference is too large, the tab 132 or the conductive sheet 133 may be bent due to downward pressure on the components during welding. Bending and extrusion may result in metal debris, so the height difference needs to be limited to an appropriate range.

[0034] In this embodiment, one side of the conductive sheet 133 is welded to the tab 132, and the other side of the conductive sheet 133 is provided with conductive adhesive to bond to the adjacent tab 132. The adhesive layer tightly bonds the electrode layers 13 together. This design further ensures that there are no gaps between the tabs 132 of each layer, ensuring a good welding effect between the tabs 132 and the corresponding components. In some embodiments, the conductive adhesive may not be applied to the other side of the conductive sheet 133.

[0035] The conductive sheet 133 is made of the same material as the electrode 11. If the electrode 11 is made of aluminum, the conductive sheet 133 is also made of aluminum. If the electrode 11 is made of copper, the conductive sheet 133 is also made of copper. The same material is conducive to welding effect and ensuring consistent temperature rise. Of course, the material of the conductive sheet 133 can also be selected from other materials, as long as it is conductive and does not affect the welding of the tabs and corresponding components. The conductive sheet 133 is made of the same material as the electrode 11, which can provide a larger conductive and thermal conduction channel, improve the battery rate performance, and increase the heat dissipation area to reduce the temperature rise.

[0036] In this embodiment, the electrode sheet 11 can be a positive electrode sheet or a negative electrode sheet, and the positive electrode tab 132 and the negative electrode tab 132 can be located at two axial ends of the electrode assembly 1 respectively, or at the same axial end.

[0037] The conductive sheet 133 of the electrode assembly 1 is welded to one of the battery housing 2 and the current collector 3 .

[0038] Specifically in this embodiment, each electrode layer 13 is provided with tabs 132 at both ends along the axial direction, one end being a positive tab 132 and the other end being a negative tab 132. Both the positive tab 132 and the negative tab 132 are provided with corresponding conductive sheets 133 between the electrode layers 13. The positive tab 132 is welded to the current collector 3 and then welded to the positive electrode post, or it can be welded directly to the positive electrode post. The negative tab 132 is welded to the bottom of the battery case 2. If both the positive tab 132 and the negative tab 132 are welded directly to the battery case 2, the busbar can be eliminated, thereby reducing the weight of the battery 100. The excess space can be used to increase the width of the coating area 131, thereby increasing volume utilization and improving energy density.

[0039] If the positive electrode tab 132 and the negative electrode tab 132 are at the same end of the electrode assembly 1 , it is sufficient to simply adjust the electrical connection relationship.

[0040] The electrode assembly of the present invention is manufactured using the following preparation method.

[0041] Step 1: Prepare the positive electrode sheet: Coat the positive electrode active material in the positive electrode coating area 131. Then, for the positive electrode sheet coated with the positive electrode active material, roll-weld the corresponding conductive sheet 133 at the positive electrode ear 132 at the preset position along its length extension direction. The spacing between the conductive sheets 133 increases accordingly with the number of winding turns, ensuring that the conductive sheets 133 in each welding area are continuous and concentrated after winding.

[0042] Step 2: Prepare the negative electrode sheet: Coat the negative electrode active material in the negative electrode coating area 131. For the negative electrode sheet coated with the negative electrode active material, roll-weld the corresponding conductive sheet 133 at the negative electrode ear 132 at the preset position along its length extension direction. The spacing between the conductive sheets 133 increases accordingly with the increase in the number of winding turns to ensure that the conductive sheets 133 in each welding area are continuous and concentrated after winding.

[0043] Step 3: stack the separator-negative electrode sheet-separator-positive electrode sheet in sequence and wind them to form an electrode assembly, one end of the electrode assembly is the positive electrode ear 132, and the other end is the negative electrode ear 132.

[0044] The electrode assembly, battery 100, and electrical device of the present invention can weld the tab 132 to the corresponding component without reshaping the tab 132, thus preventing the tab 132 from breaking during the reshaping process and generating metal debris that could fall into the battery cell and cause a short circuit. Furthermore, the thickness of the weld area is ensured to be consistent, reducing the risk of weld explosions and diaphragm burns and improving process stability. The conductive sheet 133 increases the flow area of ​​the battery 100 and improves its flow capacity. The conductive sheet 133 is a metal sheet that improves the heat dissipation capacity of the battery 100.

[0045] The electrical devices of this embodiment can be automobiles, mobile phones, portable devices, laptop computers, ships, spacecraft, electric toys, and electric tools, etc. Automobiles can be fuel-powered vehicles, gas-powered vehicles, or new energy vehicles. New energy vehicles can be pure electric vehicles, hybrid vehicles, or extended-range vehicles, etc.; spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc.; electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc.; electric tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. The present utility model does not impose any special restrictions on the above-mentioned electrical devices.

[0046] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0047] The above-described embodiments merely represent several implementations of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements fall within the scope of protection of the present invention. Therefore, the scope of protection of the present utility model patent shall be determined by the appended claims.

Claims

1. An electrode assembly, characterized in that: The electrode assembly (1) comprises a pole piece (11) and a diaphragm (12). The electrode assembly (1) is formed by stacking the pole piece (11) and the diaphragm (12) and winding them in one direction. After the electrode assembly (1) is wound, a multi-layer electrode layer (13) is formed along its radial direction. Each electrode layer (13) comprises a pole ear (132) and a coating area (131) coated with an active material. A plurality of conductive sheets (133) are arranged at intervals along the circumferential direction between the pole ears (132) of two adjacent electrode layers (13). Each conductive sheet (133) contacts and is electrically connected to the pole ears (132) on both sides. Along the radial direction of the electrode assembly (1), there is a projection of overlapping portions of the conductive sheets (133) of each layer.

2. The electrode assembly according to claim 1, wherein: Symmetrical planes of adjacent conductive sheets (133) between adjacent electrode layers (13) coincide with each other.

3. The electrode assembly according to claim 2, wherein: At least one side of adjacent conductive sheets (133) between adjacent electrode layers (13) is coplanar.

4. The electrode assembly according to any one of claims 1 to 3, characterized in that: Each electrode layer (13) has the same number of conductive sheets (133), and each electrode layer (13) has three to six conductive sheets (133).

5. The electrode assembly according to any one of claims 1 to 3, characterized in that: The electrode assembly (1) comprises a conductive area composed of adjacent conductive sheets (133) and tabs (132), and a welding area for welding, wherein the projection of the welding area in the axial direction is located within the conductive area.

6. The electrode assembly according to any one of claims 1 to 3, characterized in that: The thickness of the conductive sheet (133) is greater than the distance between two adjacent layers of the pole tabs (132); and / or the height difference between one end of the conductive sheet (133) away from the coating area (131) and one end of the pole tab (132) away from the coating area (131) is greater than or equal to 0 and less than or equal to 1 mm.

7. The electrode assembly according to any one of claims 1 to 3, characterized in that: One side of the conductive sheet (133) is welded to the pole lug (132), and the other side of the conductive sheet (133) is provided with conductive glue for bonding with the adjacent pole lug (132); and / or the conductive sheet (133) and the pole sheet (11) are made of the same material.

8. A battery, characterized in that: The battery (100) comprises an electrode assembly (1) according to any one of claims 1 to 7, a battery housing (2) for accommodating the electrode assembly (1), and a current collector (3); the conductive sheet (133) of the electrode assembly (1) is welded to one of the battery housing (2) and the current collector (3).

9. The battery according to claim 8, characterized in that: Each of the electrode layers (13) is provided with pole ears (132) at both ends along the axial direction, one end is a positive pole ear (132), and the other end is a negative pole ear (132), and the positive pole ear (132) and the negative pole ear (132) are both provided with conductive sheets (133) between the electrode layers (13), the positive pole ear (132) and the current collector (3) are welded and fixed, and the negative pole ear (132) and the bottom of the battery housing (2) are welded and fixed.

10. An electrical device, characterized in that: The electrical device comprises the battery (100) according to any one of claims 8 to 9.

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