Battery

Abstract

Battery characterized in that it comprises the following: a housing (1) on which a battery terminal assembly (31) is arranged; a cylindrical winding cell (2) comprising a winding cell body (222) and several connecting tabs (221) serving for electrical connection with the battery terminal assembly (31) or the housing (1), wherein the several connecting tabs (221) are arranged in several layers in the radial direction of the winding cell body (222); wherein in the unfolded state of the cylindrical winding cell (2) the width of a single connecting tab (221) in the longitudinal direction of the cylindrical winding cell (2) is designated as E, where: 2 mm ≤ E ≤ 9 mm; where the difference between the maximum thickness and the minimum thickness of the coiled cell body (222) is called d and the number of coiled layers of the coiled cell body (222) is called n, where: 0.08 ≤ d · n ≤ 0.9.

Description

Technical field

[0001] The present invention relates to the field of battery technology, in particular a battery. Technical background

[0002] In the prior art, the electrical connection in a battery cell is often made via connecting tabs and the battery terminal, or via an adapter plate. For example, if a direct electrical connection between the connecting tabs and the battery terminal is required, several connecting tabs are cut from an edge of the terminal section during the battery cell manufacturing process. After the terminal section is wound, the connecting tabs are flattened at the appropriate points to establish an electrical connection with the battery terminal.

[0003] However, since the terminal section includes a current collector and an active substance layer, an uneven thickness of the terminal section can occur after the active substance is applied to the current collector and the subsequent rolling process. This leads to a larger gap between the front and back layers after winding, which in turn results in poor alignment of the terminal tabs in the radial direction of the battery cell. This can later lead to a reduction in the weld area between the terminal tabs and the battery terminal, which in turn leads to insufficient current conductivity. Content of the invention

[0004] Against this background, the present invention offers a battery with which the problem of insufficient current conductivity due to poor alignment of the terminal tabs in the radial direction of the battery cell can be solved.

[0005] The present invention provides a battery comprising the following: a housing on which a battery terminal assembly is arranged; a cylindrical winding cell comprising a winding cell body and several connecting tabs for electrical connection to the battery terminal assembly or housing, wherein the several connecting tabs are arranged in multiple layers in the radial direction of the winding cell body; where, in the unfolded state of the cylindrical winding cell, the width of a single connecting tab in the longitudinal direction of the cylindrical winding cell is designated as E, where: 2 mm ≤ E ≤ 9 mm; where the difference between the maximum thickness and the minimum thickness of the coiled cell body is denoted as d and the number of coiled layers of the coiled cell body is denoted as n, where: 0.08 ≤ d · n ≤ 0.9. Beneficial effects:

[0006] In the battery according to the embodiment of the present invention, good alignment of the terminal tabs is achieved by controlling the ratio between the number of winding layers and the thickness difference of the winding cell body. This ensures a sufficient welding surface for the terminal tabs and guarantees current conductivity. Furthermore, limiting the width E of the individual terminal tabs to 2 mm ≤ E ≤ 9 mm ensures that each terminal tab is small and narrow. Several terminal tabs extend from the winding cell body of the cylindrical winding cell, with cut edges formed between them. This allows the terminal tabs to overlap after winding the cylindrical winding cell, thus forming a terminal area and ensuring a sufficient welding surface.If, however, a single large terminal tab is used, wrinkling or even buckling of the terminal tab can occur during winding of the cylindrical winding cell, which negatively affects the weld area. Therefore, the large terminal tab is divided into several smaller terminal tabs by incorporating cut lines to prevent wrinkling during winding. However, due to the thickness difference of the pole piece, layer misalignment of the terminal tabs can easily occur during winding. Furthermore, since small terminal tabs are used, a gap exists between individual terminal tabs adjacent to each other in the circumferential direction of the cylindrical winding cell, increasing the risk of layer misalignment. Therefore, the ratio between the thickness difference d and the number of winding layers n must be strictly controlled to avoid significant layer misalignment and a resulting inadequate electrical connection area. Images

[0007] To better illustrate the technical solutions in the specific embodiments of the present invention or from the prior art, the accompanying drawings used to describe the specific embodiments or the prior art are briefly presented below. It is evident that the accompanying drawings depict some embodiments of the present invention in the following description, from which further drawings can be derived by a person skilled in the art without any inventive step. These drawings show Fig. 1 a schematic representation of a battery according to the invention; Fig. 2 a schematic exploded view of a battery according to the invention; Fig. 3 a schematic representation of a cylindrical winding cell according to the invention in a top view; Fig. 4 a schematic representation of a pole piece according to the invention in the unfolded state; Fig. 5 a schematic representation of a multi-point measurement in the unfolded state of a pole piece according to the invention; Fig. 6 a schematic representation of section AA in Fig. 5; Fig. 7 a schematic representation of another type of connecting tabs in the unfolded state of a pole piece according to the invention. Reference symbol list

[0008] 1. Housing; 2. Cylindrical wound cell; 21. Terminal tab area; 22. Terminal piece; 221. Terminal tab; 222. Wound cell body; 223. Single-layer terminal tab assembly; 224. Thinned area; 3. Cover; 31. Battery terminal assembly; 32. Adapter plate. Description of embodiments

[0009] To better understand the problem, the embodiments, and the advantages of the exemplary embodiments of the present invention, the embodiments of the exemplary embodiments of the present invention are described clearly and completely below with reference to the drawings. It is obvious that the exemplary embodiments described represent only a portion of all the exemplary embodiments of the present invention. Any further exemplary embodiment that can be derived by those skilled in the art from the exemplary embodiments of the present invention without any inventive step falls within the scope of protection of the present invention.

[0010] In the description of the present invention, the terms "central," "top," "bottom," "left," "right," "vertical," "horizontal," "inside," "outside," etc., are used in relation to their representation in the respective figure, solely to describe the present invention and, where necessary, to simplify the description. In other words, these terms do not implicitly or explicitly refer to the positioning, design, or operation of the device or element in question in a predetermined position, so there is no limitation of the present invention in this respect either. Furthermore, the terms "first," "second," and "third" should not be understood as implicitly or explicitly indicating a relative meaning, but serve only for descriptive purposes.

[0011] In the description of the present invention, it should be noted that the terms "attach," "connected," and "join" are to be understood in a broad sense unless expressly stated and defined otherwise. Thus, they can refer, for example, to a permanent, detachable, or one-piece connection, as well as a mechanical or electrical connection. Furthermore, direct connections, indirect connections, connections made via an intermediate piece, and internal connections between two elements are also conceivable. Those skilled in the art in this field can use the circumstances as a basis to determine the intended meaning of these terms within the context of the present invention.

[0012] Furthermore, the technical features contained in the various embodiments of the present invention described below can be combined with each other, provided they do not conflict with each other.

[0013] In the prior art, the electrical connection in a battery cell is often made via connecting tabs and the battery terminal, or via an adapter plate. For example, if a direct electrical connection between the connecting tabs and the battery terminal is required, several connecting tabs are cut from an edge of the terminal section during the battery cell manufacturing process. After the terminal section is wound, the connecting tabs are flattened at the appropriate points so that the flat connecting tabs overlap, thus forming a connecting tab welding area to facilitate welding to the battery terminal.

[0014] If all terminal tabs are ideally and evenly distributed after winding the terminal section, the effective area of ​​the terminal tab welding zone can be ensured. However, since the terminal section includes a current collector and an active substance layer, uneven thickness of the terminal section can occur after the application of the active substance to the current collector and the subsequent rolling process. This results in a larger gap between the front and back layers after winding, which in turn leads to poor alignment of the terminal tabs radially to the battery cell. This leads to excessive overlap of the terminal tabs, reducing the effective area of ​​the terminal tab welding zone; that is, the subsequent weld area between the terminal tabs and the battery terminal becomes smaller, which can easily lead to insufficient current conductivity.

[0015] In the battery according to the embodiment of the present invention, good alignment of the connection tabs is achieved by controlling the ratio between the number of winding layers and the thickness difference of a winding cell body 222 in order to subsequently ensure a sufficient welding surface for the connection tabs and to ensure current permeability.

[0016] The following will be based on the Fig. Sections 1 to 7 describe the embodiments of the present invention.

[0017] According to one embodiment of the present invention, a battery is provided comprising the following: a housing 1 on which a battery terminal assembly 31 is arranged; a cylindrical winding cell 2 comprising a winding cell body 222 and several connecting tabs 221 serving for electrical connection with the battery pole assembly 31 or the housing 1, wherein the several connecting tabs 221 are arranged in several layers in the radial direction of the winding cell body 222; wherein in the unfolded state of the cylindrical winding cell 2 the width of a single connecting tab 221 in the longitudinal direction of the cylindrical winding cell 2 is designated as E, where: 2 mm ≤ E ≤ 9 mm; where the difference between the maximum thickness and the minimum thickness of the coiled cell body 222 is called d and the number of coiled layers of the coiled cell body 222 is called n, where: 0.08 ≤ d · n ≤ 0.9.

[0018] The cylindrical winding cell 2 has a cylindrical structure, with the housing 1 being placed on the outside of the cylindrical winding cell 2. In the present embodiment, the housing 1 can be of any shape. For example, it can have the shape of a cylinder or a hexagonal prism, provided that the cylindrical winding cell 2 can be inserted into the housing 1 and thereby fixed in place.

[0019] The housing 1 includes a battery terminal assembly 31, which is used for subsequent electrical connection with other structures, for example with a busbar, to output current.

[0020] The housing 1 comprises a housing body and a cover 3, wherein the battery terminal assembly 31 can be arranged on the housing body or on the cover 3.

[0021] The winding cell body 222 consists of a wound pole piece. In the present embodiment, the winding cell body 222 refers in particular to a region in which, in the unfolded state, the thinned region 224 is removed in the width direction of the pole piece.

[0022] The width of a single connecting tab 221 is understood to be the width of a single connecting tab 221 in the longitudinal direction of the cylindrical winding cell 2 in its unfolded state. For measurement, the winding cell body 222 can be laid flat, in which case the size of a connecting tab 221 measured in the longitudinal direction of the pole piece corresponds to the width of the connecting tab 221.

[0023] The design of a single connecting tab 221 can be varied. For example, it can be rectangular (as in Fig. 4 shown) or trapezoidal (as in Fig. 7 shown) or have a special form.

[0024] Since various design forms are conceivable for individual connection tabs 221, there are also differences regarding the measurement of the width E of the individual connection tabs 221. For a rectangular individual connection tab, the width refers to the dimension in the longitudinal direction of the cylindrical winding cell 2 in its unfolded state. For a trapezoidal individual connection tab, the width refers to the maximum dimension in the longitudinal direction of the cylindrical winding cell 2 in its unfolded state.

[0025] In the battery according to the embodiment of the present invention, good alignment of the terminal tabs is achieved by controlling the ratio between the number of winding layers and the thickness difference of a winding cell body 222, in order to subsequently ensure a sufficient welding surface for the terminal tabs and to guarantee current conductivity. Furthermore, by limiting the range of values ​​for the width E of the individual terminal tabs 221 to 2 mm ≤ E ≤ 9 mm, each terminal tab 221 is a small terminal tab with a narrow width. Several terminal tabs 221 extend from the winding cell body 222 of the cylindrical winding cell 2, with cut edges formed between them so that, after winding the cylindrical winding cell 2, the terminal tabs 221 can overlap each other and thus form a terminal tab area 21 to ensure a sufficient welding surface.If, however, a single large terminal tab is used, wrinkling or even buckling of the terminal tab can occur during the winding of the cylindrical winding cell 2, which adversely affects the weld area. Therefore, the large terminal tab is divided into several smaller terminal tabs by incorporating cut lines to prevent wrinkling during winding. However, due to the thickness difference of the pole piece, layer misalignment of the terminal tabs can easily occur during winding. Furthermore, since small terminal tabs are used, a gap exists between them, increasing the risk of layer misalignment. Therefore, the ratio between the thickness difference d and the number of winding layers n must be strictly controlled to avoid significant layer misalignment and a resulting inadequate electrical connection area.

[0026] In the present embodiment, the value for the width E of a single connecting tab 221 can be 2 mm or 3 mm or 4 mm or 5 mm or 6 mm or 8 mm or 9 mm etc.

[0027] In the present embodiment, an opening is formed on one side of the housing 1 along the axis, with the cover 3 covering the opening of the housing 1 and the cylindrical winding cell 2 arranged inside the housing 1. In a variant, the housing 1 can also form openings on both sides along the axis, with the cover 3 covering the openings of the housing 1.

[0028] The cylindrical winding cell 2 comprises a pole piece 22, which can in particular be subdivided into a positive pole piece and a negative pole piece, wherein the cylindrical winding cell 2 is produced by first stacking and then winding the positive pole piece, the negative pole piece and a separator.

[0029] After the winding of the cylindrical winding cell 2 is completed, the several connection tabs 221 are stacked in such a way that the connection tab area 21 is created, which serves for electrical connection with the battery terminal assembly 31 or the housing 1 in order to conduct the current of the cylindrical winding cell 2 out of the battery.

[0030] The battery terminal assembly 31 comprises a battery terminal and an adapter plate 32, wherein the adapter plate 32 is fixedly connected to the battery terminal on one side and to the connection tab area 21 on the other side.

[0031] In the present embodiment, the pole piece 22 comprises several connection tabs 221. The pole piece 22 is wound into a cell, with each layer of the cell comprising several connection tabs 221. The multiple connection tabs 221 located in the connection tab area 21 of the same layer of the cell form a single-layer connection tab group 223. If the thickness of the pole piece is well uniform, after winding the cylindrical cell 2, the distances between the layers are uniform in the radial direction and the adjacent single-layer connection tab groups 223 are well aligned, thus effectively ensuring the effective area of ​​the connection tab area 21 and thereby guaranteeing the weld area between the connection tab area 21 and the battery terminal. If, on the other hand, the thickness of the pole piece is uneven, i.e.,If the difference between the maximum and minimum thickness of the wound cell body 222 is large, the alignment of the radially adjacent single-layer terminal tab groups 223 is poor. With a larger number of winding layers, the layer misalignment of the terminal tabs is further increased, which in turn easily leads to an insufficient effective area of ​​the terminal tab region 21. This reduces the weld area between the terminal tab region 21 and the battery terminal and easily results in insufficient current conductivity. By comprehensively controlling the ratio of the difference d between the maximum and minimum thickness of the wound cell body 222 to the number of winding layers n of the cylindrical wound cell 2, the alignment of the terminal tabs in the radial direction of the battery cell can be ensured as far as possible, and the occurrence of terminal tab misalignment can be effectively reduced.

[0032] If d·n is too large, i.e., if the difference between the maximum and minimum thickness of the wound cell body 222 is large, or if the number of winding layers is large, or if both are true, this can easily lead to poor alignment of the terminal tabs in the radial direction of the battery cell, reducing the weld area between the terminal tab area 21 and the battery terminal, which can easily lead to insufficient current conductivity.

[0033] If d·n is too small and the difference between the maximum and minimum thickness of the wound cell body 222 is small, strict requirements for the production process conditions are necessary, which complicates the implementation of the process and significantly increases production costs. If the number of winding layers is low, this easily leads to a low energy density of the battery.

[0034] The terminal 22 comprises a positive terminal and a negative terminal, the positive terminal comprising a positive current collector and a positive active substance layer, and the negative terminal comprising a negative current collector and a negative active substance layer. There are no particular restrictions on the positive current collector, provided it is conductive and does not cause adverse chemical changes in the battery. For example, the positive current collector can be made of stainless steel, aluminum, nickel, titanium, burnt carbon, or aluminum or stainless steel that has undergone a surface treatment with one of the following substances: carbon, nickel, titanium, or silver. The negative current collector can be made of copper, stainless steel, nickel, titanium, etc. In a specific embodiment, the positive terminal can be made of aluminum and the negative terminal of copper.

[0035] The positive active substance comprises a positive active material, including ternary nickel-cobalt-manganese materials, lithium iron phosphate materials, lithium manganese iron phosphate materials, etc. The negative active substance comprises a negative active material, including synthetic graphite, natural graphite, silicon-based materials, etc.

[0036] After the active substance is applied to the current collector and the subsequent rolling process, the thickness of the winding cell body 222 can be uneven. To determine the thickness of the winding cell body 222 and thus obtain its maximum and minimum thicknesses, the winding cell body 222 can be flattened during the actual measurement, and then a specific area in the central region, the front region, and the rear region (as in Fig. 5 shown: Select area X1, area X2, area X3) and perform multiple measurements (as shown in Fig. Figure 5 shows that the circles in areas X1, X2, and X3 represent random measurement points) to determine the respective maximum and minimum thickness in these areas (as shown in Figure 5). Fig. Figure 6 shows that the maximum thickness in region X1 is denoted as d1 and the minimum thickness as d2. The minimum thickness is then subtracted from the maximum thickness of these regions to determine the difference d between the maximum and minimum thickness of the winding cell body 222. In particular, in the present embodiment, the value for the area selected in the central region, the front region, and the rear region can be 2500 mm². 2 The number of measurement points is calculated as follows: 50 are randomly selected in each of the central area, the front section, and the rear area.

[0037] In some embodiments, several connecting tabs 221 are present in one and the same layer.

[0038] “Several” means two or more.

[0039] Several connecting tabs 221 extend from the winding cell body 222 of the cylindrical winding cell 2. Cut edges are formed between these tabs so that, after winding the cylindrical winding cell 2, the connecting tabs 221 can overlap each other, thus forming a connecting tab area 21 to ensure a sufficient welding surface. Since a gap also exists between the connecting tabs, increasing the risk of layer misalignment, the ratio between the thickness difference d and the number of winding layers n must be strictly controlled to avoid significant layer misalignments.

[0040] In some embodiments, the difference d between the maximum thickness and the minimum thickness of the winding cell body 222 ≤ 0.002 mm ≤ d ≤ 0.012 mm.

[0041] In the present embodiment, the difference d between the maximum thickness and the minimum thickness of the winding cell body 222 can be, in particular, 0.002 mm or 0.005 mm or 0.008 mm or 0.010 mm or 0.011 mm or 0.012 mm, etc.

[0042] By controlling the difference d between the maximum and minimum thickness of the winding cell body 222, good uniformity of the distances between the individual layers in the radial direction is achieved after winding the cylindrical winding cell 2, thus ensuring good alignment of the connection tabs. In this way, it is ensured that a sufficient welding surface is available for the connection tabs later to guarantee current conductivity.

[0043] If the difference d between the maximum and minimum thickness of the wound cell body 222 exceeds an upper limit, the thickness of the wound cell body 222 is uneven, which, after winding, easily leads to an increased gap between the front and back layers. This, in turn, leads to poor alignment of the terminal tabs in the radial direction of the battery cell, causing the terminal tabs 221 to overlap excessively. This reduces the effective area of ​​the terminal tab region 21, which in turn reduces the weld area between the terminal tab region 21 and the battery terminal, easily resulting in insufficient current conductivity.

[0044] If the difference d between the maximum and minimum thickness of the winding cell body 222 exceeds a lower limit, strict requirements for the production process conditions are necessary, which makes the implementation of the process more difficult and significantly increases production costs.

[0045] In some embodiments, the radial dimension of the connecting tab 221 is designated as H, where: 240 ≤ H / d ≤ 5000.

[0046] The smaller the radial dimension H of the connection tab 221, the stricter the accuracy requirements between the offset layers. When the radial dimension H of the connection tab 221 is smaller, the cross-sectional area for current flow is smaller. In this case, the difference d must be smaller to ensure uniformity of the connection tab thickness, thereby reducing the risk of layer misalignment and preventing insufficient current conductivity.

[0047] In some embodiments, the terminal tab 221 comprises a positive terminal tab and a negative terminal tab, wherein the positive terminal tab and the negative terminal tab are located on the same side of the wound cell body 222 in the axial direction. One of the positive and negative terminal tabs is electrically connected to the battery terminal assembly 31 and the other to the housing 1, where: 0.12 ≤ d · n ≤ 0.8.

[0048] The positive and negative terminals are located on the same side of the wound cell body 222 in the axial direction. Because the positive and negative terminals extend from the same side, the battery terminal and the housing 1 each act as outputs and are electrically connected to the positive and negative terminals, respectively. This results in a shorter current path and lower resistance for the subsequent electrical connection. Conversely, if the positive and negative terminals extend from different sides, the current path of the terminal on one side must pass through the housing, making the current path longer and increasing resistance.

[0049] Since the positive and negative terminal tabs are located on the same side of the winding cell body 222 in the axial direction, they must share the area of ​​the same end face of the winding cell body 222, which reduces the area available for each terminal tab. Therefore, the area of ​​d·n is further optimized to 0.12 ≤ d·n ≤ 0.8 to further ensure the alignment of the terminal tabs, provide sufficient welding area for the terminal tabs, and guarantee current conductivity.

[0050] In some embodiments, the cylindrical winding cell 2 has a diameter D, where: 40 mm ≤ D ≤ 56 mm.

[0051] If the positive and negative terminal tabs are located on the same side of the winding cell body 222 in the axial direction, the layer offset of the terminal tabs worsens the insufficient current conductivity of the positive and negative poles. Therefore, the diameter of the cylindrical winding cell 2 must be designed to be relatively large in order to increase the available area for the positive and negative terminal tabs, respectively, and thus ensure sufficient current conductivity.

[0052] In the present embodiment, the value for the diameter D of the cylindrical winding cell 2 can be 40 mm or 42 mm or 45 mm or 47 mm or 49 mm or 50 mm or 52 mm or 56 mm, etc.

[0053] In some embodiments, the radial dimension of the connecting tab 221 is designated as H and the diameter of the cylindrical winding cell 2 as D, where: 0.05 ≤ H / D ≤ 0.25.

[0054] It should be noted that the dimension H of the connecting tab 221 in the radial direction can be measured as the distance between the end facing the winding cell body 222 and the end facing away from the winding cell body 222 of the connecting tab 221 in the width direction of the winding cell in the unfolded state of the cylindrical winding cell 2.

[0055] If the positive and negative terminal tabs exit from the same side, they share the same end face of the battery cell, resulting in a relatively small current-carrying area for each tab. Therefore, the height-to-diameter ratio (H / D) must be controlled. H / D must not be too small, as this would require more terminal tab layers, increasing the risk of layer misalignment. Conversely, H / D must not be too large, as this would increase the radial dimensions of the terminal tab and raise the risk of it buckling during winding.Furthermore, because the positive and negative connection tabs are located on the same side, there is a risk of short-circuiting if the radial dimension of the connection tab is too long, allowing the positive and negative connection tabs of the innermost layer, closest to the center of the winding cell, to easily overlap. The overlap of the positive and negative connection tabs can be further explained as follows: The connection tabs initially stand upright, are then flattened, and folded over towards the end face. If the connection tabs were too long, the risk of overlap between the innermost positive and negative connection tabs would increase.

[0056] In some embodiments, the connecting tab 221 is rectangular, where: 0.002 mm ≤ d ≤ 0.008 mm.

[0057] Alternatively, the connecting tab 221 is trapezoidal in shape, where: 0.002 mm ≤ d ≤ 0.01 mm.

[0058] With rectangular connecting tab 221, the gap between the connecting tabs of the same layer is larger, so the probability of a resulting offset further along is greater. Therefore, the area of ​​d must be smaller.

[0059] If the connecting tab 221 has the shape of a trapezoid, the gap between the connecting tabs of the same layer is smaller, so the probability of a subsequent misalignment is lower. Therefore, the area of ​​d can be somewhat larger.

[0060] In some embodiments, the multiple connecting tabs 221 are stacked in such a way that a connecting tab area is created which is fan-shaped in the radial direction, wherein: 0.003 mm ≤ d ≤ 0.012 mm.

[0061] The terminal tab area 21 has a fan-shaped design, allowing it to adapt well to the shape of the battery cell. Stacking multiple terminal tabs 221 to create the terminal tab area 21 minimizes the risk of terminal tab misalignment, thus allowing for a larger permissible range for d.

[0062] Furthermore, the range of d in the present embodiment can preferably be as follows: 0.003 mm ≤ d ≤ 0.0085 mm.

[0063] Furthermore, the range of d in the present embodiment can preferably be as follows: 0.0035 mm ≤ d ≤ 0.011 mm.

[0064] In some further embodiments, the connecting tab 221 comprises a positive connecting tab and a negative connecting tab, wherein the positive connecting tab and the negative connecting tab are located on both sides of the winding cell body 222 in the axial direction. The radial dimension of the connecting tab 221 is designated as H and the diameter of the cylindrical winding cell 2 as D, where: 0.03 ≤ H / D ≤ 0.2.

[0065] In the present embodiment, the positive and negative terminal tabs are located axially on both sides of the cell body 222. This means that the positive and negative terminal tabs extend from different sides, so they do not have to share the area of ​​the same end face of the cell body 222. This ensures that the area for arranging the positive and negative terminal tabs is increased, allowing the H / D ratio to be set relatively small. This reduces the overlap of terminal tabs between adjacent layers and prevents the terminal tab area from becoming too thick after the tabs are folded over. This is particularly important because, during the processing of a battery cell, terminal tabs are first cut from the terminal section, initially standing upright and then bent over.If H is too large, the connecting tabs will overlap significantly after bending, increasing the thickness of the battery assembly's connecting tabs. This also increases the risk of the connecting tabs folding over during winding.

[0066] In some embodiments, the connecting tab 221 is rectangular, where: 0.003 mm ≤ d ≤ 0.0085 mm.

[0067] Alternatively, the connecting tab 221 is trapezoidal in shape, where: 0.0035 mm ≤ d ≤ 0.011 mm.

[0068] Since the positive and negative terminal tabs can be located on different end faces of the battery cell, the area of ​​the positive and negative terminal tabs can be made larger. Therefore, in an embodiment where the positive and negative terminal tabs extend from different sides, compared to an embodiment where the positive and negative terminal tabs extend from the same side, the difference d between the maximum and minimum thickness of the wound cell body 222 can be slightly increased in order to reduce the limitations regarding the process conditions during machining of the pole piece and to increase production efficiency.

[0069] In some embodiments, the difference between the number of connecting tabs 221 of the radially outermost layer and the number of connecting tabs 221 of the radially innermost layer is denoted as m, where m is greater than or equal to 3 and 0.002 mm ≤ d ≤ 0.01 mm.

[0070] Due to the thickness difference d, the terminal tabs of different winding layers can become misaligned after winding. If m is relatively small, e.g., if m is 1 or 2, the risk of an overall layer misalignment of the terminal tabs after winding is relatively low. However, if the difference m between the number of terminal tabs 221 of the outermost layer and the number of terminal tabs 221 of the innermost layer is relatively large, for example, if m is greater than or equal to 3, there is an increased risk of an overall layer misalignment after completion of the winding. This can lead to an increase in the circumferential distance between the terminal tabs of the outermost layer closest to the edge and the terminal tabs of the innermost layer closest to the edge. The terminal tabs and the battery terminal assembly are primarily welded together in the central area.As the risk of layer misalignment increases, the effective welding area decreases, leading to impaired current flow. Therefore, the value range of d must be controlled more precisely to further reduce the risk of layer misalignment.

[0071] Additionally, the difference m between the number of connecting tabs 221 of the outermost layer and the number of connecting tabs 221 of the innermost layer is such that m is less than or equal to 8.

[0072] Limiting the upper limit of m prevents the formation of too many layers and avoids limiting the thickness difference of the connecting tabs too strictly, which would lead to excessively strict conditions for the machining of the pole piece.

[0073] In some embodiments, such as in Fig. As shown in Figure 3, the connecting lines between the connecting tabs 221 of the radially outermost layer or the connecting tabs 221 of the radially innermost layer and the axis of the cylindrical winding cell 2 enclose an angle A, where: 0° < A ≤ 18°.

[0074] It should be noted that the connecting tabs of the radial outermost layer and the connecting tabs of the radial innermost layer refer to the connecting tabs of the outermost layer and the connecting tabs of the innermost layer that are closest to the edge, respectively.

[0075] By limiting the angle enclosed by the connecting lines between the terminal tabs of the outermost layer or the terminal tabs of the innermost layer and the axis of the cylindrical winding cell 2, the offset of the terminal tabs is limited to a certain area in order to avoid impairing the current flow area of ​​the terminal tabs further along.

[0076] In some embodiments, the thickness of the winding cell body 222 is designated as C, where: C ≥ 0.080 mm and 0.12 ≤ d · n ≤ 0.8.

[0077] If the thickness C of the winding cell body 222 ≥ 0.080 mm, the thickness of the winding cell body 222 is relatively large. After winding the cylindrical winding cell 2, the gap between the layers in the radial direction is relatively large, which increases the risk of layer misalignment of the connecting tabs and results in poor alignment of the radially adjacent single-layer connecting tab groups 223, so that a smaller value for d·n is required.

[0078] Furthermore, with larger thicknesses it is more difficult to control the uniformity of the pole piece's thickness during the rolling process.

[0079] In some embodiments, the cylindrical winding cell 2 comprises a thinned region 224, wherein the difference between the maximum thickness and the minimum thickness of the cylindrical winding cell 2 in the thinned region 224 is referred to as F, where: 8 µm ≤ F ≤ 60 µm.

[0080] As in Fig. As shown in Figure 6, the thinned area 224 designates specific regions of the coating on the terminal 22 where the applied material is thinner than in other regions, resulting in a gradient-distributed structure. The thickness of the thinned area is one of the most important parameters influencing battery performance. First, thinning the terminal reduces the battery's internal resistance, thereby increasing its discharge power and charging speed. Second, appropriate thinning increases the specific surface area of ​​the positive terminal, thus increasing the contact area between the electrode material and the electrolyte, and consequently, the battery's energy density and cycle life.However, if the thinned area is too thin, it can also lead to a reduction in the mechanical strength of the terminal piece and thus impair the safety of the battery.

[0081] The thinned area is located closer to the root of a terminal tab. Since the subsequent bending process of the terminal tab begins at a point near the root, the risk of terminal tab misalignment between different layers increases if the thickness varies significantly in the thinned area. If the difference F between the maximum and minimum thickness of the coiled cell body 222 in the thinned area exceeds the upper limit, the thickness of the coiled cell body 222 in the thinned area becomes uneven. This results in individual terminal tabs and front terminal tabs not being radially distributed, thereby increasing the terminal tab misalignment and reducing the effective area of ​​the terminal tab area 21, i.e., the subsequent weld area between the terminal tab area 21 and the battery terminal. This can easily lead to insufficient current conductivity.

[0082] If the difference F between the maximum and minimum thickness of the winding cell body 222 in the thinned area exceeds the lower limit, strict requirements for the production process conditions are necessary, which makes the implementation of the process more difficult and significantly increases production costs.

[0083] In some embodiments, the number of winding layers n of the cylindrical winding cell 2 n ≤ 200 applies.

[0084] If the number of winding layers n of the cylindrical winding cell 2 exceeds the upper limit, the cylindrical winding cell 2 has a relatively high number of winding layers. The accumulation of defects further increases the layer misalignment of the terminal tabs, which in turn easily leads to an insufficient effective area of ​​the terminal tab area 21. This reduces the weld area between the terminal tab area 21 and the battery terminal, easily resulting in insufficient current conductivity. Conversely, if the number of winding layers n of the cylindrical winding cell 2 exceeds the lower limit, this can easily lead to a low energy density of the battery.

[0085] In some embodiments, the cylindrical winding cell 2 comprises, as in Fig.Figure 3 shows a positive pole piece and a negative pole piece. After winding the cylindrical winding cell 2, the multiple connection tabs 221 of the positive pole piece are stacked to form a positive connection tab area, while the multiple connection tabs 221 of the negative pole piece are stacked to form a negative connection tab area. The positive connection tab area and the negative connection tab area are located on the same side of the cylindrical winding cell 2 in the axial direction and are spaced apart from each other.

[0086] It is obvious that the preceding embodiments serve only for clarification and do not represent a limitation of the embodiments. Although the embodiments of the present invention have been described in conjunction with the drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, all of which fall within the scope of the present invention.

[0087] The present invention relates to the field of battery technology and discloses a battery comprising: a housing including a battery terminal assembly; a cylindrical wound cell comprising a wound cell body and several connecting tabs extending from the wound cell body, which connecting tabs serve for electrical connection with the battery terminal assembly or the housing, wherein the several connecting tabs are arranged in multiple layers in the radial direction of the wound cell body. A single connecting tab has a width E, for which 2 mm ≤ E ≤ 9 mm. Furthermore, the difference between the maximum and minimum thickness of the wound cell body is referred to as d, and the number of winding layers of the wound cell body is referred to as n, wherein: 0.08 ≤ d · n ≤ 0.9.In the battery according to the invention, the alignment of the terminal tabs in the radial direction of the battery cell can be ensured as far as possible by comprehensively controlling the ratio of the difference d between the maximum and minimum thickness of the wound cell body to the number of winding layers n of the battery cell, and the occurrence of offset of the terminal tabs can be effectively reduced. This ensures a uniform gap between the front and rear layers after winding, which guarantees an effective welding surface and sufficient current conductivity.

Claims

[1] Battery, characterized by that it includes the following: a housing (1) on which a battery terminal assembly (31) is arranged; a cylindrical winding cell (2) comprising a winding cell body (222) and several connecting tabs (221) serving for electrical connection with the battery terminal assembly (31) or the housing (1), wherein the several connecting tabs (221) are arranged in several layers in the radial direction of the winding cell body (222); wherein in the unfolded state of the cylindrical winding cell (2) the width of a single connecting tab (221) in the longitudinal direction of the cylindrical winding cell (2) is designated as E, where: 2 mm ≤ E ≤ 9 mm; where the difference between the maximum thickness and the minimum thickness of the coiled cell body (222) is called d and the number of coiled layers of the coiled cell body (222) is called n, where: 0.08 ≤ d · n ≤ 0.

9. [2] Battery according to claim 1, characterized by , that there are several connecting tabs (221) in one and the same layer. [3] Battery according to claim 1, characterized by , that for the difference d between the maximum thickness and the minimum thickness of the coiled cell body (222) 0.002 mm ≤ d ≤ 0.012 mm. [4] Battery according to claim 1, characterized by , that the dimension of the connecting tab (221) in the radial direction is designated as H, where: 240 ≤ H / d ≤ 5000. [5] Battery according to claim 1, characterized by , that the connection tab (221) comprises a positive connection tab and a negative connection tab, which are located on the same side of the wound cell body (222) in the axial direction, wherein one of the positive connection tabs and the negative connection tab is electrically connected to the battery terminal assembly (31) and the other to the housing (1), wherein: 0.12 ≤ d · n ≤ 0.

8. [6] Battery according to claim 5, characterized by , that the cylindrical winding cell (2) has a diameter D, where: 40 mm ≤ D ≤ 56 mm. [7] Battery according to claim 5, characterized by , that the dimension of the connecting tab (221) in the radial direction is designated as H and the diameter of the cylindrical winding cell (2) as D, where: 0.05 ≤ H / D ≤ 0.

25. [8] Battery according to claim 5, characterized by , that the connecting tab (221) is rectangular, wherein: 0.002 mm ≤ d ≤ 0.008 mm, or that the connecting tab (221) is trapezoidal, wherein: 0.002 mm ≤ d ≤ 0.01 mm. [9] Battery according to claim 1, characterized by , that the multiple connecting tabs (221) are stacked in such a way that a connecting tab area (21) is created which is fan-shaped in the radial direction, wherein: 0.003 mm ≤ d ≤ 0.012 mm. [10] Battery according to claim 1, characterized by, that the connecting tab (221) comprises a positive connecting tab and a negative connecting tab, which are located on both sides of the winding cell body (222) in the axial direction, wherein the dimension of the connecting tab (221) in the radial direction is designated as H and the diameter of the cylindrical winding cell 2 is designated as D, wherein: 0.03 ≤ H / D ≤ 0.

2. [11] Battery according to claim 10, characterized by , that the connecting tab (221) is rectangular, wherein: 0.003 mm ≤ d ≤ 0.0085 mm, or that the connecting tab (221) is trapezoidal, wherein: 0.0035 mm ≤ d ≤ 0.011 mm. [12] Battery according to claim 1, characterized by , that the difference between the number of connecting tabs (221) of the radially outermost layer and the number of connecting tabs (221) of the radially innermost layer is denoted as m, where m is greater than or equal to 3 and 0.002 mm ≤ d ≤ 0.01 mm. [13] Battery according to claim 1, characterized by, that the connecting lines between the connecting tabs (221) of the radially outermost layer or the connecting tabs (221) of the radially innermost layer and the axis of the cylindrical winding cell (2) enclose an angle A, where: 0° < A ≤ 18°. [14] Battery according to claim 1, characterized by , that the thickness of the coiled cell body (222) is designated as C, where: C >_ 0.080 mm and 0.12 ≤ d · n ≤ 0.

8. [15] Battery according to claim 1, characterized by , that the cylindrical winding cell (2) includes a thinned region, wherein the difference between the maximum thickness and the minimum thickness of the cylindrical winding cell (2) in the thinned region is called F, where: 8 µm ≤ F ≤ 60 µm. [16] Battery according to claim 12, wherein m is less than or equal to 8. [17] Battery according to claim 15, wherein the thickness of the thinned area is less than that of the coated area in the pole piece (22). [18] Battery according to claim 15 or 17, wherein the thinned area is closer to the root through which the terminal tab is connected to the cell body. [19] Battery according to any one of claims 1 to 18, wherein a shear joint is provided between adjacent connecting tabs (221) or a gap is provided between the connecting tabs (221). [20] Battery according to any one of claims 1 to 19, wherein the number of winding layers n of the cylindrical winding cell (2) is n ≤ 200. [21] Battery according to any one of claims 1 to 20, wherein the battery terminal assembly (31) comprises a battery terminal and an adapter plate (32), wherein the adapter plate (32) is fixedly connected to the battery terminal on one side and is connected to the connecting tabs (221) on the other side.

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