Individual batteries, battery packs, and electronic devices

Abstract

The present invention provides a standalone battery that can solve the problem of the outer ring tab of the electrode member bending outward due to the force received during the process of inserting the electrode member into the case. [Solution] The present invention provides a standalone battery, a battery pack, and an electronic device. The standalone battery includes a case, an electrode member, and a current collector. The first extension of the current collector extends outward from the outer edge of the main body in the radial direction of the main body and contacts the outer ring tab. The second extension is connected at one end to the main body between two adjacent first extensions, and the other end is electrically connected to a roller groove. The outer edge of the second extension forms an outer edge surface along the circumferential direction, and the outer edge surface is orthogonally projected onto a plane perpendicular to the height direction in which the outer ring tab is located along the height direction of the electrode member to form an outer edge surface projection, and the outer edge surface projection at least partially overlaps with each outer ring tab between two adjacent first extensions. As a result, the problem of case insertion failure due to an increased electrode member diameter can be solved.

Description

Technical Field

[0001] The present invention relates to the field of batteries, and more specifically, to single cells, battery packs, and electronic devices.

Background Art

[0002] In recent years, with the rapid development of electric vehicles, consumer electronic devices, and new energy storage systems, for electric vehicles, battery technology has become an important factor related to their development.

[0003] In the development of battery technology, how to improve the assembly efficiency of batteries is a technical problem that needs to be urgently solved in battery technology.

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present invention is to provide a single cell that can solve the problem that the outer ring tab of the electrode member warps outward due to the force received during the process steps when the electrode member is inserted into the case.

Means for Solving the Problems

[0005] A first aspect of the present invention provides a single battery, comprising a case, an electrode member, and a current collector. The case includes a cylindrical side wall, one end of which includes an opening, and the side wall forms a roller groove recessed into the case near the opening. The electrode member is housed within the case, and the roller groove restricts the movement of the electrode member within the case in the height direction of the single battery. One end of the electrode member near the roller groove in the height direction has a tab, which is bent toward the central hole of the electrode member, and the tab closest to the outer edge of the electrode member constitutes the outer ring tab of the electrode member. The current collector comprises a main body, a plurality of first extensions, and a plurality of second extensions, the main body being positioned between the roller groove and the electrode member, and one side surface of the main body being electrically connected to the tab. The first extensions are coplanar with the main body and extend outward from the outer edge of the main body in the radial direction of the main body to contact the outer ring tab. One end of the second extension is connected to the main body between two adjacent first extensions, and the other end is electrically connected to the roller groove. The outer edge of the second extension forms an outer edge surface along the circumferential direction, and the outer edge surface is orthogonally projected onto a plane perpendicular to the height direction in which the outer ring tabs are located along the height direction of the electrode member to form an outer edge surface projection, which overlaps with at least a portion of each outer ring tab between two adjacent first extensions.

[0006] In a single battery of an optional technical proposal of the present invention, the second extension portion includes a roller groove fixing portion and a bridge portion, the ends of which are connected to the outer edge of the main body portion and the roller groove fixing portion, respectively, the roller groove fixing portion is welded to the surface of the roller groove away from the electrode member, and the bridge portion is bent to undergo stress deformation toward the roller groove, or the tab is a cut-and-stacked tab.

[0007] In the single battery of the selectable technical proposal of the present invention, the stress deformation is elastic deformation, and when the fixing of the second extension portion and the roller groove is released, the end of the bridge portion closest to the roller groove elastically recovers so as to deform in a direction away from the electrode member.

[0008] In a single battery of the selectable technical proposal of the present invention, the second extension is electrically connected to the roller groove by welding, and each roller groove fixing portion is welded and fixed to the roller groove using a plurality of weld marks that are separated from each other.

[0009] In the single battery of the selectable technical proposal of the present invention, the weld mark is a linear weld mark extending along the circumferential direction.

[0010] In the single battery of the selectable technical proposal of the present invention, the length L of each weld mark satisfies 2 mm ≤ L ≤ (W - (n + 1)) / n mm, where W is the maximum circumferential length of each roller groove fixing part, both L and W are in mm, and n is the number of weld marks on each roller groove fixing part. More preferably, n = 2, and the range of the value of W is 14 mm to 18 mm.

[0011] In a single battery of the selectable technical proposal of the present invention, the current collector has four first extensions evenly distributed along the circumferential direction and four second extensions evenly distributed along the circumferential direction, the first extensions and second extensions are installed sequentially at intervals, and each first extension and each second extension leaves a gap around the outer edge of the main body.

[0012] A single battery of an optional technical proposal of the present invention further includes a cover used to seal the opening of the case. The other end of the side wall includes an end wall, the end wall having mounting holes used for mounting poles. Between the poles and the end wall, an insulating component is further provided, used to electrically insulate the end wall from the poles. The diameter d of the cylindrical battery and the depth D of the roller groove satisfy the formula relation: 12 ≤ d / D ≤ 23. More preferably, the depth D of the roller groove satisfies D ≤ 4 mm.

[0013] A second aspect of the present invention provides a battery pack including a single battery provided in the first aspect of the present invention.

[0014] A third aspect of the present invention provides an electronic device including a battery pack provided in the second aspect of the present invention. [Effects of the Invention]

[0015] The single battery, battery pack, and electronic device of the present invention can solve the problem that during the process of inserting the electrode member into the case, the outer ring tab warps outward from the electrode member due to the force received during the steps of the assembly process, the diameter of the electrode member increases, and poor case insertion occurs.

Brief Description of the Drawings

[0016] [Figure 1] It is an explanatory diagram of the structure of the electrode member in the present embodiment. [Figure 2] It is an explanatory diagram of the structure of the negative electrode tab in the present embodiment. [Figure 3] It is a perspective explanatory diagram of the first current collector in the present embodiment. [Figure 4] It is an explanatory diagram of the upper surface of the first current collector in the present embodiment. [Figure 5] It is a projection explanatory diagram on the plane where the outer ring tab along the Z direction of the first current collector is located after welding the first current collector and the negative electrode tab in the present embodiment. [Figure 6] It is an explanatory diagram of the state where the electrode member welded with the first current collector is inserted into the case in the present embodiment. [Figure 7] [[ID=...]] It seems there are some line numbers skipped in the original for better readability. If you want to continue the translation for the remaining parts, please provide the complete text. It is a state explanatory diagram of the welding connection process between the first current collector and the case in the present embodiment. [Figure 8] It is an explanatory diagram of the fitting between the press-fitting jig and the roller groove fixing part in the present embodiment. [Figure 9] It is an explanatory diagram of the structure of the single battery in the present embodiment. [Figure 10] It is a partially enlarged view of FIG. 9. [Figure 11] It is an explanatory diagram of the upper surface of the single battery in the present embodiment after removing the cover. [Figure 12] It is a partially enlarged view of FIG. 11. [Figure 13] It is an explanatory diagram of the battery pack in the present embodiment. [Figure 14] It is an explanatory diagram of the electronic device in the present embodiment. [Figure 15]This is an explanatory diagram of the partial structure of a single cell in this embodiment.

Embodiments for Carrying out the Invention

[0017] It should be noted that hereinafter, the structural features and advantages of the single cell according to the present invention will be described by way of an exemplary method. However, all descriptions are provided only for illustrative purposes and do not form any limitation to this application.

[0018] In addition, with respect to any single technical feature described or implied in the embodiments referred to in the text, or any single technical feature shown or implied in each attached drawing, this application still permits any combination or reduction among these technical features (or their equivalents) to be continuously carried out, and there is no technical obstacle, thereby enabling the obtaining of more other embodiments of this application that may not be directly referred to in the text.

[0019] <Summary> In a conventional single cell, its electrode member is formed by winding a positive electrode sheet, a separator, and a negative electrode sheet. A tab is installed at the end of the electrode member, and it is made parallel to the end face of the electrode member by shaping such as bending, and then welded to the main body part of the current collector. After the welding is completed, the electrode member and the current collector are inserted into the case together, and the extending part of the current collector is welded to the inner circumference of the case.

[0020] However, in the process of inserting the electrode member into the case, the outer-ring tab may warp due to the force received in the process steps, the diameter of the electrode member increases, which affects the assembly accuracy. In addition, there are difficulties in the welding operation between the extending part of the current collector and the inner circumference of the case, and the situation of poor welding is likely to occur, further affecting the overall performance and reliability of the battery.

[0021] Referring generally to the figures, an exemplary embodiment shows an electrode member 2, a first current collector 3 connected to the negative electrode tab 20 of the electrode member 2, a case 1 housing the electrode member 2 and electrically connected to the first current collector 3, and a standalone battery 100 having the above-mentioned components. By improving the design of the first current collector 3 and the coupling structure between the first current collector 3 and the case 1, advantages such as easier assembly of the standalone battery 100 and enhanced stability of the connection structure of the standalone battery 100 are obtained.

[0022] <Electrode Member 2> Figure 1 is a diagram illustrating the structure of the electrode member 2 in this embodiment. The electrode member 2 is formed by winding a positive electrode sheet, a separator, and a negative electrode sheet. The positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer. The positive electrode current collector includes a coated region and an uncoated region. The positive electrode active material layer is coated on the coated region of the positive electrode current collector, and the uncoated region of the positive electrode current collector forms a positive electrode tab. The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer. The negative electrode current collector includes a coated region and an uncoated region. The negative electrode active material layer is coated on the coated region of the negative electrode current collector, and the uncoated region of the negative electrode current collector forms a negative electrode tab 20.

[0023] As a specific example, the material of the positive electrode current collector may be aluminum, and the positive electrode active material layer may contain a positive electrode active material, which may be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. The material of the negative electrode current collector may be copper, and the negative electrode active material layer may contain a negative electrode active material, which may be carbon or silicon. The material of the diaphragm may be PP (polypropylene) or PE (polyethylene), etc. To provide protection and insulation to the electrode member 2, an insulating film can be further coated on its exterior, and the insulating film can be synthesized from PP, PE, PET, PVC, or other polymer materials.

[0024] Continuing to refer to Figure 1, the multiple negative electrode tabs 20 are shown in a bent and stacked state. Several methods can be employed to form the negative electrode tabs 20 as shown in Figure 1. For example, one specific implementation method involves making cuts in the uncoated area of ​​the negative electrode current collector and folding it, dividing it into multiple tabs, then performing a flattening process from the height direction of the electrode member to make the negative electrode tabs 20 parallel to the end face of the electrode member 2, thereby facilitating welding with the first current collector 3, which will be described later. Although the state of the positive electrode tabs is not shown in Figure 1, it can be understood that the positive electrode tabs can have a similar state to the negative electrode tabs 20, and will not be described in detail here.

[0025] Among the multiple negative electrode tabs 20, the negative electrode tab 20 that is bent toward the central hole 21 of the electrode member 2 and is closest to the outer edge of the electrode member 2 constitutes the outer ring tab 201 of the electrode member 2. Note that the outer ring tab 201 refers to the negative electrode tab 20 that is bent at the outermost edge, and is not necessarily the outermost negative electrode tab 20. This is because, in some embodiments, as shown in Figure 2 (direction A is the direction away from the central hole 21), the outermost negative electrode tab 20 is not bent, and this negative electrode tab 20 is not the outer ring tab 201 described in this text.

[0026] <First current collector 3> Figure 3 shows a perspective view of the first current collector 3 in this embodiment. Figure 4 shows a top view of the first current collector 3 in this embodiment. The first current collector 3 in Figure 4 does not show the holes shown in Figure 3, but it can be understood that the first current collector 3 in Figure 4 can actually have similar holes, they are just not shown in the figure.

[0027] As shown in Figure 3, the first current collector 3 includes a main body 30, a plurality of first extensions 31, and a plurality of second extensions 32. The main body 30 has an annular shape, and the four first extensions 31 are located on the same plane as the main body 30. The first extensions 31 extend outward from the outer edge of the main body 30 in the radial direction, forming a shape similar to a flower petal. Here, the statement that the first extensions 31 and the main body 30 are located on the same plane means that both the first extensions 31 and the main body 30 are electrically connected mainly to the negative electrode tab 20 of the electrode member 2, and since the negative electrode tab 20 is basically located on the same plane, the first extensions 31 and the main body 30 are also basically located on the same plane. Note that "same plane" here includes the same plane or approximately the same plane. This is because, after a single battery undergoes chemical formation and charging / discharging, some deformation may occur in the first extension portion 31 and the main body portion 30, but even then they remain close to or substantially on the same plane. The second extension portion 32 includes a roller groove fixing portion 321 and a bridge portion 322. One end of the roller groove fixing portion 321 is connected to the main body portion 30 between two adjacent first extension portions 31, and the other end is connected to the roller groove fixing portion 321. The roller groove fixing portion 321 is used to make a conductive connection with the roller groove 101 of the case 1, which will be described in detail later. Note that the plane in which the roller groove 101 of the case 1 is located and the plane in which the negative electrode tab 20 is located are offset in the height direction of the electrode member 2, i.e., in the Z direction. Therefore, as shown in Figure 3, the roller groove fixing portion 321 is offset in the Z direction from the main body portion 30 and the first extension portion 31, and the bridge portion 322 has a height in the Z direction.

[0028] As shown in Figure 4, the outer edges of the multiple first extensions 31 and the multiple second extensions 32 achieve 360° coverage in the circumferential direction. The advantages of this installation will be described in detail later.

[0029] To ensure that it is understood that the shape of the main body 30, the number and shape of the first extensions 31, and the number and shape of the second extensions 32 shown in the illustrated embodiments are merely examples and do not constitute a limitation on the present invention. In other embodiments, the number of the first extensions 31 and the second extensions 32 may be three or six.

[0030] <Assembly process> The following describes the process by which the first current collector 3 connects to the electrode member 2 and the case 1, respectively.

[0031] First, the first current collector 3 is connected to the negative electrode tab 20 by welding, and the main body portion 30 and the first extension portion 31 of the first current collector 3 are connected to the negative electrode tab 20, ensuring that the first extension portion 31 maintains contact with the outer ring tab 201. Next, the electrode member 2 to which the first current collector 3 has been welded is inserted into the case 1, that is, the case insertion process is performed.

[0032] Figure 5 is a projected diagram illustrating the plane in which the outer ring tab 201 of the first current collector 3 is located along the Z direction, after welding the first current collector 3 and the negative electrode tab 20 in this embodiment.

[0033] As shown in Figure 5, the gray area represents the projection 903 of the first current collector. Here, the first extension 31 is parallel to the plane on which the negative electrode tab 20 is located, and the first extension 31 is connected to the negative electrode tab 20, so the projection 9031 of the first extension 9031 and the first extension 31 basically completely overlap in shape.

[0034] Referring to Figure 5, taking as an example the two upper first extension projections 9031 in Figure 5 and the outer edge projection 9032 between the two first extension projections 9031, the left first extension projection 9031 overlaps with at least a portion of the outer ring tabs 201a, 201b, 201c, 201d, and 201e (each of the outer ring tabs 201a, 201b, 201c, 201d, and 201e corresponds to one tab), and the right first extension projection 9031 overlaps with at least a portion of the outer ring tabs 201j, 201k, 201m, and 201n. Each of the outer ring tabs 201f, 201g, 201h, and 201i between the two first extension projections 9031 (i.e., between the two first extensions 31 corresponding to the two first extension projections 9031) all overlaps, at least partially, with the outer edge surface projection 9032 of the second extension 32.

[0035] The fact that the left-hand projection of the first extension portion 9031 in the above text overlaps with at least a portion of the outer ring tabs 201a, 201b, 201c, 201d, and 201e indicates that the first extension portion 31 corresponding to the first extension portion projection 9031 is in contact with the outer ring tabs 201a, 201b, 201c, 201d, and 201e, thereby preventing the outer ring tabs 201a, 201b, 201c, 201d, and 201e from warping due to the influence of process steps (e.g., airflow) during the case insertion process. Similarly, the fact that the right-side first extension projection 9031 overlaps with at least a portion of the outer ring tabs 201j, 201k, 201m, and 201n indicates that the first extension 31 corresponding to the first extension projection 9031 is in contact with the outer ring tabs 201j, 201k, 201m, and 201n, thereby preventing warping of the outer ring tabs 201j, 201k, 201m, and 201n. Furthermore, the fact that the outer edge surface projection 9032 of the second extension portion 32 between the two first extension portion projections 9031 overlaps with at least a portion of each of the outer ring tabs 201f, 201g, 201h, and 201i indicates that the outer edge surface of the second extension portion 32 corresponding to the outer edge surface projection 9032 prevents warping of the outer ring tabs 201f, 201g, 201h, and 201i during the case insertion process and avoids affecting the diameter of the electrode member 2.

[0036] Figure 6 shows an explanatory diagram of the state after the electrode member 2, to which the first current collector 3 has been welded, has been inserted into the case 1 in this embodiment. As shown in Figure 6, the free end of the bridge portion 322 (i.e., the end away from the main body portion 30) curves upward in the Z direction, thereby avoiding the rolling cutter 500 for processing the roller groove 101, and preventing interference from the first current collector 3 during the process of processing the roller groove 101.

[0037] Figure 7 shows an explanatory diagram of the welding connection process between the first current collector 3 and the case 1 in this embodiment. Referring to Figure 7, after inserting the electrode member 2, to which the first current collector 3 has been welded, into the case 1, a roller groove 101 recessed inside the case 1 can be formed near the opening 12 in the side wall 10 of the case 1 using a tool such as a rolling cutter 500. The roller groove 101 has a first wall 1011 and a second wall 1012 separated in the Z direction. The second wall 1012 can restrict the movement of the electrode member 2 along the Z direction inside the case 1. A roller groove fixing part 321 is connected to the free end of the bridge part 322. In order to avoid the rolling cutter 500 described above, when there is no external force acting on it, the roller groove fixing part 321 bends upward, thereby maintaining a certain distance from the first wall 1011. A press-fit jig 8 can be used to weld the roller groove fixing part 321 to the first wall 1011. The press-fitting jig 8 applies external force to the second extension portion 32, bending the bridge portion 322 and bringing the roller groove fixing portion 321 into close contact with the first wall 1011.

[0038] Figure 8 is an explanatory diagram of the arrangement of the press-fitting jig 8 and the roller groove fixing part 321 in this embodiment. Referring to Figure 8, the press-fitting jig 8 includes a first press-fitting member 81, a second press-fitting member 82, and a third press-fitting member 83. The first press-fitting member 81 and the second press-fitting member 82 each press down on both ends of the roller groove fixing part 321, while the third press-fitting member 83 presses down on the intermediate position of the roller groove fixing part 321. With the first press-fitting member 81, the second press-fitting member 82, and the third press-fitting member 83 pressing down on both ends and the intermediate position of the roller groove fixing part 321, welding is performed between the first press-fitting member 81 and the third press-fitting member 83, and between the second press-fitting member 82 and the third press-fitting member 83, forming two short, straight weld marks 4.

[0039] According to the welding method described above, by using a press-fitting jig 8 having a third press-fitting member 83, one crimping point is added in the middle of the roller groove fixing portion 321, and a welding method that forms two short, straight weld marks 4 is used, replacing the conventional welding method that forms one relatively long arc-shaped weld mark. In this way, since the welding adopts the form of a short, straight weld mark 4, there is no need to rotate the electrode member 2 during the welding process, thereby reducing the difficulty of welding and improving the stability of the welding. At the same time, this method can effectively avoid the problem that can occur when forming a relatively long arc-shaped weld mark in the conventional method, where an explosion point may occur in the middle of the weld mark, potentially causing poor contact.

[0040] Subsequently, the opening 12 of case 1 can be sealed using cover 5 to obtain a single battery 100 as shown in Figure 9.

[0041] In the above text, welding was used as an example to describe a conductive connection method between the first current collector 3, the negative electrode tab 20, and the roller groove 101, but the present invention is not limited thereto. As long as a conductive connection between the first current collector 3, the negative electrode tab 20, and the roller groove 101 can be achieved, there are no special limitations on the specific conductive connection method. To make it clear, the assembly process described above is merely one preferred method of implementation and does not constitute a limitation on the present invention.

[0042] <Single battery 100> Figure 9 shows a diagram illustrating the structure of a single battery 100 in this embodiment. As shown in Figure 9, as a specific example, the single battery 100 is a cylindrical battery. The single battery 100 includes a case 1, electrode members 2, pole posts 7, a cover 5, a first current collector 3, and a second current collector 6. The case 1 includes a cylindrical side wall 10 and an end wall 13 located at one end of the side wall 10. The electrode members 2 are housed inside the case 1. The pole posts 7 penetrate mounting holes in the end wall 13 and are insulated from the end wall 13 through an insulating member. The cover 5 covers and seals an opening 12 at one end of the side wall 10 away from the end wall 13. The side wall 10 forms a roller groove 101 that is recessed into the inside of the case 1 near the opening 12. The first current collector 3 is connected to the negative pole end of the electrode member 2 and to the case 1 (roller groove 101), and the second current collector 6 is connected to the positive pole end of the electrode member 2 and to the pole post 7.

[0043] Here, the specific dimensions of case 1 can be determined based on the specific dimensions of electrode member 2, for example, a diameter of 46 mm and a height of 80 mm, 95 mm, or 120 mm. The material of case 1 can be various, for example, copper, iron, aluminum, steel, or aluminum alloy. To prevent case 1 from rusting during long-term use, a layer of rust-preventive material such as metallic nickel can be electroplated onto the surface of case 1.

[0044] Figure 10 is a partially enlarged view of Figure 9. Figure 11 shows a top view of the single battery 100 in this embodiment after the cover 5 has been removed.

[0045] Referring to Figure 10, the main body portion 30 of the first current collector 3 is located between the roller groove 101 and the electrode member 2 in the Z direction, and one side surface of the main body portion 30 facing the electrode member 2 is electrically connected to the negative electrode tab 20 (not shown in Figure 9) of the negative electrode of the electrode member 2.

[0046] Referring to Figures 10 and 15, the single battery 100 is a cylindrical battery. In the cylindrical battery, the electrode member 2 is inserted into the case 1 from the negative electrode side and sealed at the negative electrode side. The cylindrical battery has an explosion-proof valve 400 installed on the negative electrode side to release pressure at the negative electrode. Therefore, the assembly process, assembly quality, and structure from the insertion of the electrode member 2 into the case 1 to sealing affect the pressure release effect of the cylindrical battery. The main functions of the explosion-proof valve include pressure release, explosion prevention, protection of the battery structure, and safety protection. When the pressure inside the lithium battery rises abnormally, the explosion-proof valve opens automatically, releasing the gas accumulated inside, thereby reducing the pressure and preventing the battery from rupturing or exploding.

[0047] Referring to Figures 10 and 11, the first extension 31 of the first current collector 3 is coplanar with the main body 30 and extends outward radially from the outer edge of the main body 30. The second extension 32 has one end connected to the main body 30 between two adjacent first extensions 31, and the other end conductively connected to the first wall 1011 of the roller groove 101. The depth D of the roller groove 101 satisfies D ≤ 4 mm. The depth D of the roller groove 101 refers to the depth to which the roller groove 101 is recessed against the side wall 10 of the case 1, specifically the depth along the radial direction of the case 1 in Figure 10.

[0048] In the illustrated embodiment, the cross-section of the roller groove 101 is U-shaped, and the second extension portion 32 is fixed to the first wall 1011 of the roller groove 101, but the present invention is not limited thereto. As long as the structure has a recessed groove formed from the side wall 10 toward the inside of the case 1, it is within the technical scope of the roller groove 101 described by the present invention. The second extension portion 32 can be fixed at any position on the roller groove 101 suitable for conductive connection, and there are no particular limitations. The depth D of the roller groove 101 is generally relatively small, for example, 4 mm or less, but in other embodiments, the depth D may be greater than 4 mm.

[0049] Figure 11 shows a top view of the standalone battery 100 in this embodiment after the cover 5 has been removed. At this time, the first current collector 3 is electrically connected to both the negative electrode tab 20 and the roller groove 101. Figure 5 shows a projected view in this embodiment of the plane in which the outer ring tab 201 of the first current collector 3 is located along the Z direction, when the first current collector 3 is electrically connected to the negative electrode tab 20 but not yet electrically connected to the roller groove 101. There is some change in the position of the second extension portion 32 before and after the conductive connection with the roller groove 101, but this change is minute. Therefore, by referring to Figure 5, it is possible to understand the projected view in the plane in which the outer ring tab 201 of the first current collector 3 is located along the Z direction in the standalone battery 100 after shipment.

[0050] Referring to Figures 11 and 5, the first extension portion 31 extends radially outward from the outer edge of the main body portion 30 and contacts the outer ring tab 201. The outer edge of the second extension portion 32 forms an outer edge surface along the circumferential direction, and the outer edge surface is orthogonally projected onto the plane on which the outer ring tab 201 is located along the height direction of the electrode member 2 (this plane is basically perpendicular to the Z direction) to form an outer edge surface projection 9032, which overlaps with at least a portion of each outer ring tab 201 between two adjacent first extension portions 31. Specifically, the outer edge surface can be formed by the plane on which the roller groove fixing portion 321 is located, or by the plane on which the roller groove fixing portion 321 and its circumferential extension portion are located.

[0051] The contact between the first extension portion 31 and the outer ring tab 201 allows the first extension portion 31 to effectively hold down the corresponding outer ring tab 201, preventing warping during the case insertion process. At the same time, the contact between the first extension portion 31 and the outer ring tab 201 also contributes to reducing internal resistance. As for the second extension portion 32, since its outer edge projection 9032 overlaps at least partially with the outer ring tab 201, when the first current collector 3 is welded to the electrode member 2 and inserted into the case 1, it limits the degree of warping of the corresponding outer ring tab 201 (i.e., the degree to which it deviates from the Z direction away from the central hole 21), thus preventing the outer ring tab 201 from warping outward from the electrode member 2. Furthermore, since the second extension portion 32 does not apply pressure to the outer ring tab 201, it is advantageous for smooth pressure release when the battery cell experiences thermal runaway, and is particularly effective in cylindrical batteries where pressure release occurs at the negative electrode. Furthermore, by having the outer edge projection 9032 of the second extension portion 32 overlap with at least a portion of each outer ring tab 201 between two adjacent first extension portions 31, it is ensured that each outer ring tab 201 is subject to direct contact with the first extension portion 31 or limitations on the degree of curvature by the second extension portion 32 during the case insertion process, thereby preventing an increase in the diameter of the electrode member 2. By installing multiple first extension portions 31 and multiple second extension portions 32, not only can the above-mentioned curvature prevention effect be achieved, but it is also possible to reduce the overall weight of the first current collector 3 while ensuring functionality. Note that the outer ring tab 201 corresponding to the second extension portion 32 may have a certain degree of curvature, but if the degree of curvature is large, it will be limited by the second extension portion 32, preventing further curvature outward of the electrode member 2 and avoiding any impact on the diameter of the electrode member 2. Here, when we say that the outer ring tab 201 bends outward from the electrode member 2, we mean that the projection of the endpoint of the outer ring tab 201 away from the electrode member 2 onto a plane perpendicular to the Z direction exceeds the range in which the end face of the electrode member 2 is located.

[0052] In some embodiments, referring to Figure 11, the second extension 32 includes a roller groove fixing portion 321 and a bridge portion 322, the ends of which are connected to the outer edge of the main body portion 30 and the roller groove fixing portion 321, respectively, and the roller groove fixing portion 321 is welded to the surface of the roller groove 101 away from the electrode member 2. Because the roller groove fixing portion 321 is welded to the surface of the roller groove 101 away from the electrode member 2, the stress of the bridge portion 322 connected to the roller groove fixing portion 321 toward the roller groove 101 is appropriate, resulting in better adhesion between the roller groove fixing portion 321 and the roller groove 101. This is advantageous for improving welding operability and welding quality. Preferably, the bridge portion 322 and the adjacent first extension portions 31 on both sides are separated, which is advantageous for reducing the overall weight of the first current collector 3 and for smooth pressure release during thermal runaway. In the illustrated embodiment, the bridge portion 322 has a uniform width, but in other embodiments, the bridge portion 322 may have curved sides.

[0053] In some embodiments, the bridge portion 322 is bent to undergo stress deformation toward the roller groove 101. This stress deformation is elastic deformation, and when the second extension portion 32 and the roller groove 101 are released, the end of the bridge portion 322 closest to the roller groove 101 elastically returns to its original position, deforming away from the electrode member 2. Refer to Figure 6 and the above description of the assembly process for assembly. After the electrode member 2, to which the first current collector 3 is welded, is inserted into the case 1, the free end of the bridge portion 322 is higher in the Z direction than the position for forming the roller groove 101 on the side wall 10, thereby avoiding interference between the jig for machining the roller groove 101 (such as a rolling cutter 500) and the first current collector 3. Therefore, when the bridge portion 322 is not subjected to external force, its free end is offset from the roller groove 101 in the Z direction, and it is necessary to achieve a conductive connection between the roller groove fixing portion 321 and the roller groove 101 through bending by external force. Specifically, the bridge portion 322 is bent to undergo stress deformation toward the roller groove 101, and the roller groove fixing portion 321 connected to the free end of the bridge portion 322 is electrically connected to the roller groove 101. Because the bridge portion 322 is bent to undergo stress deformation toward the roller groove 101, when the fixing between the second extension portion 32 and the roller groove 101 is released, for example, after the bridge portion 322 electrically connected to the roller groove 101 is cut, the bridge portion 322 elastically returns to a direction away from the electrode member 2 in the Z direction.

[0054] In some embodiments, the height of the outer ring tab 201 in the freely extended state is H1, which can also be defined as the distance from the edge of the negative electrode current collector in the electrode member 2 to the edge of the active material layer. As shown in Figure 10, in the assembled state, the distance from the first extended portion 31 to the second extended portion 32 is H2, and the range of the value of H1 / H2 is 1.1 to 2. The height H1 of the outer ring tab 201 is slightly greater than H2, and this range of values ​​effectively prevents warping of the outer ring tab 201 and prevents the second extended portion 32 from applying pressure to the outer ring tab 201 when assembled, thus facilitating smooth pressure release during thermal runaway.

[0055] In some embodiments, as shown in Figure 10, the diameter d of a cylindrical battery-type individual battery 100 and the depth D of the roller groove 101 satisfy the following mathematical relationship: 12 ≤ d / D ≤ 23. Here, the diameter d of the individual battery 100 refers to the maximum diameter of the cross-section of the cylindrical battery, which in some cases is the outer diameter of the case 1. The depth D of the roller groove 101 includes the thickness of the case 1. In some embodiments, the depth D of the roller groove 101 is 4 mm or less.

[0056] As shown in Figure 11, each roller groove fixing part 321 is welded to the roller groove 101 using multiple spaced weld marks 4, and the weld marks 4 are linear weld marks 4 extending in the circumferential direction. In conjunction with Figure 8 and the above-described assembly process, each roller groove fixing part 321 is welded to the roller groove 101 by multiple spaced weld marks 4, thereby effectively ensuring the vortex area and avoiding the problem of welding defects caused by explosion points in the middle of relatively long weld marks. Specifically, if a single weld mark is used, the weld mark needs to have a certain length in order to ensure the vortex area. However, for the following two reasons, relatively long weld marks tend to cause explosion points in the middle and lead to poor contact. On the one hand, for the reasons mentioned above, the second extension part 32 is pressed onto the roller groove 101 by the force it receives and has a certain elastic stress. On the other hand, the surface of the roller groove 101 is not perfectly flat, making it difficult to make complete contact with the roller groove fixing part 321. The multiple separated, relatively short weld marks 4 provided in this embodiment can effectively avoid problems that may arise from relatively long weld marks.

[0057] Furthermore, because the depth D of the roller groove 101 is relatively small, the main continuous contact surface between the second extension portion 32 and the roller groove 101 is located in the circumferential direction. Therefore, installing a linear weld mark 4 that extends in the circumferential direction is helpful in improving the stability of the weld. At the same time, adopting a linear weld mark 4 is also helpful in simplifying the welding process. Specifically, when arc welding is required, the electrode member 2 must rotate in accordance with the welding speed, which is relatively difficult to operate. However, the linear weld mark 4 in this embodiment avoids the problem of the complexity of arc welding operation.

[0058] In summary, by employing multiple linear weld marks 4, not only is welding quality guaranteed, but production efficiency is also significantly improved.

[0059] In some embodiments, referring to Figure 12, each roller groove fixing part 321 is welded to the roller groove 101 using a plurality of weld marks 4 spaced apart from each other, and the length L of each weld mark 4 satisfies 2 mm ≤ L ≤ (W - (n + 1)) / n mm, where W is the maximum circumferential length of each roller groove fixing part 321, i.e., the distance between the two farthest endpoints on the circumferential direction of the roller groove fixing part 321, and n is the number of weld marks 4 on each roller groove fixing part 321. When the length L of the weld marks 4 satisfies the above mathematical relationship, the length L of the weld marks 4 is not excessively short, thereby ensuring an overflow area, and at the same time, the length L of the weld marks 4 is not excessively long, thereby avoiding the occurrence of explosion points and being advantageous for improving welding quality.

[0060] Preferably, n=2, and the range of the value of W is 14mm to 18mm. When the number of weld marks 4 on each roller groove fixing part 321 is 2, the welding quality is better. When the number of weld marks 4 on each roller groove fixing part 321 exceeds 2, the welding efficiency may decrease, and problems such as instability of the laser device due to an excessively short welding length may occur. When the range of the value of the maximum circumferential length W of each roller groove fixing part 321 is 14mm to 18mm, it becomes easier to operate when welding multiple weld marks 4.

[0061] In the selectable technical proposals for a single battery of the present invention, the maximum circumference of the single battery is C, and the range of the C / W value is 7 to 11. Considering the ease of welding, the welding area, and the shielding effect on the negative electrode tab 20, C / W is preferably a value within 7 to 11. For example, when the diameter of the case 1 of the single battery 100 is 46 mm, C is 144.44 mm, and based on the preferred range of C / W, W is preferably a value such as 14 mm, 15 mm, 16 mm, or 17 mm.

[0062] In some embodiments, referring to Figure 11, each roller groove fixing portion 321 is welded to the roller groove 101 using a plurality of weld marks 4 that are separated from each other, and the current collector has four first extensions 31 and four second extensions 32 that are evenly distributed in the circumferential direction, and the first extensions 31 and second extensions 32 are installed sequentially at intervals, and each first extension 31 and each second extension 32 leaves a gap 33 in advance on the outer edge of the main body 30. With the above installation, the current in the first extensions 31 is effectively transmitted through the second extensions 32, forming a stable current path. In addition, by installing four first extensions 31 and four second extensions 32 that are evenly distributed in the circumferential direction, the angle between two adjacent first extensions 31 and two adjacent second extensions 32 can be set to 90°, and this symmetry is advantageous in production. For example, because the angles of the second extensions 32 are evenly spaced, precise angle control can be achieved when a single battery 100 rotates and welds another second extension 32. This simplifies the welding process and improves the consistency and stability of the weld. Furthermore, the pre-existing gap 33 releases the elastic stress of the second extension 32, preventing damage to the first current collector 3 due to tearing, and also avoids interference with the welding of the first extension 31 and the negative electrode tab 20.

[0063] As described above, the technical proposals in some embodiments of the present invention can be effectively applied to individual cylindrical batteries 100. Cylindrical batteries pursue extreme energy density and have a large group margin (group margin is the ratio of the maximum diameter of the electrode member 2 to the maximum inner diameter of the case 1, and the group margin of cylindrical batteries is generally 94% to 99%), which results in a very narrow tolerance range for the process of assembling the electrode member 2 into the case 1. However, by installing the first current collector 3 provided in some embodiments of the present invention, assembly efficiency can be effectively improved and the problem of assembly defects due to the excessive diameter of the electrode member 2 can be avoided.

[0064] <Battery Pack 700> Figure 13 shows an explanatory diagram of the battery pack 700 in this embodiment. As shown in Figure 13, the battery pack 700 includes a housing 710, a box lid 720, and a plurality of individual batteries 100. The plurality of individual batteries 100 are arranged in the housing 710 and connected to each other in series, parallel, or a combination of series and parallel. The box lid 720 covers the housing 710 and provides protection for the plurality of individual batteries 100. It should be noted that the battery pack 700 may include parts other than the individual batteries 100 of the present invention, such as a thermal management system and a circuit board. The battery pack 700 may be a battery module, a battery pack, or a power storage cabinet, and these will not be explained individually here.

[0065] <Electronic equipment 800> Figure 14 shows an explanatory diagram of the electronic device 800 in this embodiment. As shown in Figure 14, the electronic device 800 includes the battery pack 700 described above and a work unit 600 that is electrically connected to the battery pack 700. As an example, the electronic device 800 is a vehicle, which may be a fuel-fueled vehicle, a gasoline vehicle, or a new energy vehicle, and the new energy vehicle may be, but is not limited to, a pure electric vehicle, a hybrid vehicle, or a range extender vehicle. The work unit 600 is the vehicle body, and the battery pack 700 is installed at the bottom of the vehicle body and provides power assistance for the vehicle's movement or the operation of in-vehicle electrical components. However, in some other embodiments, the electronic device 800 may further be a mobile phone, a portable device, a laptop computer, a ship, an aircraft, an electric toy, and a power tool, etc. Aircraft include airplanes, rockets, space shuttles, and spacecraft, etc. The work unit 600 may be a unit component that can obtain power from the battery pack 700 and perform a corresponding task, such as a fan blade rotation unit or a vacuum cleaner dust collection unit. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric boat toys, and electric airplane toys. Power tools include metal cutting power tools, polishing 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. The embodiments of this application do not impose any special limitations on the electronic devices 800 described above.

[0066] The foregoing are merely preferred embodiments of the present invention and are not intended to limit it. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should all be included within the scope of protection of the present invention. [Industrial applicability]

[0067] The individual battery, battery pack, and electronic device described in this application can be applied in the field of battery technology. [Explanation of symbols]

[0068] 100: Single battery 1: Case 10: Side wall 101: Roller groove 1011:First wall 1012:Second wall 12:Aperture 13: End wall 2: Electrode material 20: Negative electrode tab 201: Outer ring tab 21: Center hole 3: First current collector 30: Main body 31: 1st extension part 32:Second stretching section 321: Roller groove fixing part 322: Bridge section 903: 1st current collector projection 9031: First extension part projection 9032: Outer edge surface projection 33: Gap 4: Weld marks 5: Cover 6: Second current collector 7: Polar pillar 8: Press-fitting jig 81: First press-fit member 82: Second press-fit member 83: Third press-fit member 500: Rolling Cutter 600: Work Unit 700: Battery pack 710: Cabinet 720: Box lid 800:Electronic equipment 400: Explosion-proof valve

Claims

1. It is a single battery, A case including a cylindrical side wall, wherein one end of the side wall includes an opening, and the side wall has a roller groove formed in the interior of the case near the opening, An electrode member housed within the case, wherein the roller groove restricts the movement of the electrode member along the height direction of the single battery within the case, and the electrode member has a tab at one end near the roller groove along the height direction, the tab is bent toward the central hole of the electrode member, and the tab closest to the outer edge of the electrode member constitutes the outer ring tab of the electrode member, A current collector comprising a main body, a plurality of first extensions, and a plurality of second extensions, wherein the main body is installed between the roller groove and the electrode member, and one side surface of the main body is electrically connected to the tab, Includes, The first extension portion is located on the same plane as the main body portion, and the first extension portion extends outward from the outer edge of the main body portion in the radial direction of the main body portion and contacts the outer ring tab, The second extension is connected at one end to the main body between two adjacent first extensions, and at the other end is electrically connected to the roller groove. A single battery characterized in that the outer edge of the second extension portion has an outer edge surface formed along the circumferential direction, the outer edge surface is orthogonally projected onto a plane perpendicular to the height direction in which the outer ring tab is located along the height direction of the electrode member to form an outer edge surface projection, and the outer edge surface projection overlaps with at least a portion of each of the outer ring tabs between two adjacent first extension portions.

2. The second extension portion includes a roller groove fixing portion and a bridge portion, Both ends of the bridge section are connected to the outer edge of the main body and the roller groove fixing section, respectively. The roller groove fixing portion is welded and fixed to one side of the roller groove away from the electrode member. The bridge portion is bent to undergo stress deformation toward the roller groove, or The single battery according to claim 1, characterized in that the tab is a cut-and-stack tab.

3. The aforementioned stress deformation is elastic deformation, The single battery according to claim 2, characterized in that when the fixing of the second extension portion and the roller groove is released, one end of the bridge portion closest to the roller groove elastically recovers so as to deform in a direction away from the electrode member.

4. The second extension is electrically connected to the roller groove by welding, The single battery according to claim 2, characterized in that each of the roller groove fixing portions is welded and fixed to the roller groove using a plurality of welding marks that are separated from each other.

5. The aforementioned weld mark is a linear weld mark extending along the circumferential direction, or The length L of each weld mark satisfies 2 mm ≤ L ≤ (W - (n + 1)) / n mm. Here, W is the maximum circumferential length of each roller groove fixing portion. The units for L and W are both mm. The single battery according to claim 4, characterized in that n is the number of welding marks on each of the roller groove fixing portions.

6. n = 2, or The single battery according to claim 5, characterized in that the maximum circumference of the single battery is C, and the range of the C / W value is 7 to 11.

7. The current collector has four first extended portions and four second extended portions that are evenly distributed in the circumferential direction. The first extension and the second extension are installed sequentially at intervals from each other. The single battery according to claim 1, characterized in that each of the first extension portion and each of the second extension portion leaves a gap around the outer edge of the main body portion.

8. The case further includes a cover used to seal the opening, The other end of the side wall includes an end wall, the end wall is provided with mounting holes used for attaching pole poles, and an insulating member is further provided between the pole pole and the end wall for electrically insulating the end wall from the pole pole. The aforementioned single battery is a cylindrical battery, and the diameter d of the cylindrical battery and the depth D of the roller groove satisfy the mathematical relationship: 12 ≤ d / D ≤ 23. The cover includes an explosion-proof valve which is an annular notch on the cover, or The single battery according to claim 1, characterized in that the height of the outer ring tab is H1, the distance from the first extension to the second extension is H2, and the range of the value of H1 / H2 is 1.1 to 2.

9. A battery pack characterized by including a single battery as described in any one of claims 1 to 8.

10. An electronic device characterized by including the battery pack described in claim 9.

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