Cylindrical battery cell and cylindrical battery

Abstract

The utility model provides a cylindrical battery cell and a cylindrical battery, the cylindrical battery cell comprises a positive plate, a negative plate and a diaphragm, the diaphragm separates the positive plate and the negative plate, and the edge of one end, close to the center of the cylindrical battery cell, of the positive plate is the inner end edge of the positive plate; the cylindrical battery cell further comprises one or more protective parts, the protective parts are connected with the positive plates or the diaphragms, and the protective parts cover at least one part of the edge of the inner end. The cylindrical battery cell is beneficial to reducing the risk of internal short circuit when the cylindrical battery cell collapses towards the center, and the cylindrical battery cell is relatively high in safety.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a cylindrical battery cell and a cylindrical battery. Background Technology

[0002] After multiple charge-discharge cycles, the negative electrode of a battery cell expands. For cylindrical batteries, the cell is cylindrical, and this expansion causes a portion of the cell to collapse towards its center. The central area of ​​the cylindrical cell experiences the most significant collapse and deformation. When this collapse occurs, the negative electrode, separator, and positive electrode press against each other, making the separator susceptible to punctures, tears, cuts, or damage. This can lead to internal short circuits within the cylindrical cell. Utility Model Content

[0003] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a cylindrical battery cell with a low risk of internal short circuit when the cylindrical battery cell collapses towards its center.

[0004] This utility model also proposes a cylindrical battery including the above-mentioned cylindrical cells.

[0005] A cylindrical battery cell according to a first aspect of the present invention includes a positive electrode, a negative electrode, and a separator, wherein the separator separates the positive electrode and the negative electrode, and one end edge of the positive electrode near the center of the cylindrical battery cell is the inner end edge of the positive electrode; the cylindrical battery cell further includes one or more protective members, the protective members being connected to the positive electrode or the separator, and the protective members covering at least a portion of the inner end edge.

[0006] The cylindrical battery cell according to the first aspect of this utility model has at least the following beneficial effects: In the prior art, when a cylindrical battery cell collapses towards its center, the inner edge of the positive electrode is prone to damage to the outer and inner separator layers adjacent to the inner edge, thereby making the cylindrical battery cell prone to internal short circuits. However, for the cylindrical battery cell of this application, since the protective component covers at least a portion of the inner edge, the protective component can reduce the direct contact between at least one of the outer and inner separator layers and the inner edge, thereby reducing the risk of the separator being damaged by the inner edge, and further reducing the risk of internal short circuits when the cylindrical battery cell collapses towards its center. Therefore, the cylindrical battery cell of this application has higher safety.

[0007] According to some embodiments of the present invention, the protective member completely covers the inner edge.

[0008] According to some embodiments of the present invention, in the circumferential direction of the cylindrical battery cell, a portion of the protective member protrudes beyond the inner end edge; in the axial direction of the cylindrical battery cell, the inner end edge is located between the two ends of the protective member.

[0009] According to some embodiments of the present invention, in the radial direction of the cylindrical battery cell, the protective member is located outside the inner end edge; or, in the radial direction of the cylindrical battery cell, the protective member is located inside the inner end edge; or, the cylindrical battery cell includes at least two protective members, in the radial direction of the cylindrical battery cell, at least one of the protective members is located inside the inner end edge, and at least one of the protective members is located outside the inner end edge.

[0010] According to some embodiments of the present invention, the protective member is elastic; and / or, the surface of the protective member opposite to the inner end edge is insulated.

[0011] According to some embodiments of the present invention, the protective component includes: an adhesive layer bonded to the positive electrode sheet; a buffer layer having elasticity; and an insulating layer, wherein the insulating layer, the buffer layer, and the adhesive layer are stacked on top of each other in the radial direction of the cylindrical battery cell, and the buffer layer is disposed between the insulating layer and the adhesive layer.

[0012] According to some embodiments of this utility model, the adhesive layer is made of one of acrylic acid, acrylate, silicone, polyurethane, epoxy resin, polyvinylidene fluoride, sodium carboxymethyl cellulose, and styrene-butadiene rubber; and / or, the elastic modulus of the buffer layer is not less than 0.3 GPa and not greater than 5 GPa; and / or, the insulating layer is made of one of polypropylene, polyethylene terephthalate, and polyimide.

[0013] According to some embodiments of the present invention, the ratio of the thickness of the insulating layer to the thickness of the protective component is not less than 0.3.

[0014] According to some embodiments of the present invention, the thickness of the protective component is not less than 0.02 mm and not more than 0.1 mm; and / or, the positive electrode sheet includes a positive electrode active material layer, the protective component is bonded to the positive electrode active material layer, and the porosity of the protective component is not less than 10% and not more than 40%.

[0015] A cylindrical battery according to a second aspect of the present invention includes a casing and a cylindrical cell as described in the first aspect embodiment, the cylindrical cell being located inside the casing.

[0016] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0018] Figure 1 This is a schematic diagram of the cross-section of a cylindrical battery cell in the prior art;

[0019] Figure 2 This is a schematic diagram of the cross-section of the cylindrical battery cell according to the first embodiment of the present invention;

[0020] Figure 3 This is a partial schematic diagram of the inner edge of the cylindrical battery cell in the first embodiment;

[0021] Figure 4 This is a schematic diagram of the positive electrode plate and positive electrode tab in the first embodiment;

[0022] Figure 5 This is a schematic diagram showing the positional relationship between the inner edge and the protective component in the first embodiment;

[0023] Figure 6 This is a schematic diagram of the cross-section of the protective component in the first embodiment;

[0024] Figure 7 This is a schematic diagram showing the positional relationship between the inner edge and the protective component in the second embodiment of this utility model;

[0025] Figure 8 This is a schematic diagram showing the positional relationship between the inner edge and the protective component in the third embodiment of this utility model;

[0026] Figure 9 This is a partial schematic diagram of the cylindrical battery cell according to the fourth embodiment of the present invention;

[0027] Figure 10 This is a partial schematic diagram of the cylindrical battery cell according to the sixth embodiment of this utility model.

[0028] Reference numerals: 101-Cylindrical cell, 102-Positive electrode sheet, 103-Inner edge, 104-Negative electrode sheet, 105-Separator, 106-Protective component, 107-First adjacent ring, 108-Second adjacent ring, 109-Positive tab, 110-Positive active material layer, 111-Taper groove, 112-Positive current collector, 113-First edge, 114-Second edge, 115-Insulating layer, 116-Buffer layer, 117-Adhesive layer, 118-Center hole. Detailed Implementation

[0029] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0030] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0031] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0032] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0033] Figure 1 A cross-section of a cylindrical battery cell 101 in the prior art is shown, such as... Figure 1 As shown, the cylindrical cell 101 includes a positive electrode 102, a negative electrode 104, and a separator 105 wound together, with the separator 105 separating the positive electrode 102 and the negative electrode 104. The center of the cylindrical cell 101 is hollow, and a central hole 118 is formed in the center of the cylindrical cell 101.

[0034] After multiple charge-discharge cycles, the negative electrode 104 of the cylindrical battery cell 101 will expand. In particular, to improve battery capacity and energy density, some cells use a composite material of graphite and silicon for the active material of the negative electrode 104, and silicon-containing negative electrode 104s have a relatively high expansion rate. Even if the negative electrode 104 does not contain silicon, it will still expand to some extent. Figure 1As shown, because a central hole 118 is formed in the center of the cylindrical cell 101, the expansion of the negative electrode 104 will cause a portion of the cylindrical cell 101 to collapse towards the center of the cylindrical cell 101. When the cylindrical cell 101 collapses, the negative electrode 104, the separator 105, and the positive electrode 102 will squeeze each other and the pressure between them will be relatively large. This makes the separator 105 easy to be punctured, torn, cut, or crushed, which will easily lead to an internal short circuit in the cylindrical cell 101.

[0035] For example, such as Figure 1 As shown, the inner edge 103 of the positive electrode 102, located near the center of the cylindrical cell 101, is the end edge of the positive electrode 102. The negative electrode 104 is longer than the positive electrode 102, and a portion of the negative electrode 104 is located inside the inner edge 103 in the radial direction of the cylindrical cell 101. This is mainly to increase the amount of lithium ions that the negative electrode 104 can absorb, thereby reducing the risk of lithium plating on the surface of the negative electrode 104. When the cylindrical cell 101 collapses towards its center, the inner edge 103 will press against the adjacent separator 105, potentially puncturing, breaking, or damaging the separator 105. After the separator 105 is damaged, the inner edge 103 may come into contact with the negative electrode 104, resulting in an internal short circuit.

[0036] In some other prior art (not shown), the cylindrical cell 101 also includes a central tube (not shown) that passes through a central hole 118. Since the central tube is stronger than the electrode and separator 105, it can support the electrode and separator 105, thereby reducing the risk of the cylindrical cell 101 collapsing towards its center, and consequently reducing the risk of internal short circuits due to collapse. However, adding a central tube significantly increases the cost of the cylindrical cell 101. Furthermore, adding a central tube increases the weight proportion of inactive materials in the cylindrical cell 101, thereby reducing the battery's energy density. In addition, although the central tube can reduce the risk of internal short circuits due to the cylindrical cell 101 collapsing towards its center, it can still deform or even break when the cell is subjected to a heavy impact or puncture. A deformed or broken central tube may puncture the separator 105, leading to an internal short circuit in the cylindrical cell 101.

[0037] Therefore, this application proposes a cylindrical battery cell 101. This application eliminates the need for a central tube and addresses the risk of internal short circuits caused by the cylindrical battery cell 101 collapsing towards the center through a different technical concept. Specifically, the battery cell of this application includes a positive electrode 102, a negative electrode 104, a separator 105, and a protective element 106. The separator 105 is insulating and separates the positive electrode 102 and the negative electrode 104. One or more protective elements 106 are provided, and the protective element 106 is connected to the positive electrode 102 or the separator 105. The protective element 106 covers at least a portion of the inner edge 103, thereby reducing the risk of internal short circuits caused by the cylindrical battery cell 101 collapsing towards the center.

[0038] In the prior art, when the cylindrical cell 101 collapses towards the center, the inner edge 103 of the positive electrode 102 is prone to damage to the outer separator layer (e.g., the second adjacent ring 108 hereinafter) and the inner separator layer (e.g., the first adjacent ring 107 hereinafter) adjacent to the inner edge 103, thereby making the cylindrical cell 101 prone to internal short circuit. However, for the cylindrical cell 101 of this application, since the protective member 106 covers at least a portion of the inner edge 103, the protective member 106 can reduce the direct contact between at least one of the outer and inner separator layers and the inner edge 103, thereby reducing the risk of the separator 105 being damaged by the inner edge 103, and thus reducing the risk of internal short circuit when the cylindrical cell 101 collapses towards its center.

[0039] Figure 2 A cross-section of the cylindrical battery cell 101 according to the first embodiment of this application is shown. Figure 3 It shows Figure 2 A portion of the cross-section. In the first embodiment, the protective member 106 is located inside the inner end edge 103 in the radial direction of the cylindrical cell 101. For example... Figure 3 As shown, the diaphragm 105 in a wound state is divided into multiple turns, including a first adjacent turn 107 and a second adjacent turn 108. In the radial direction of the cylindrical cell 101, the first adjacent turn 107 is located inside the second adjacent turn 108, and the inner end edge 103 is located between the first adjacent turn 107 and the second adjacent turn 108. Since the protective member 106 is located inside the inner end edge 103, the protective member 106 can reduce the direct contact area between the inner end edge 103 and the first adjacent turn 107 (compared to...). Figure 1 (As shown in the prior art). When the cylindrical cell 101 collapses towards the center, the relatively sharp inner edge 103 directly contacts less of the first adjacent ring 107, and the first adjacent ring 107 is not easily damaged by the inner edge 103, so the risk of internal short circuit in the cylindrical cell 101 is low.

[0040] In this embodiment, the protective member 106 is connected to the positive electrode 102. For example, the protective member 106 is bonded to the positive electrode 102. In other embodiments not shown, the protective member 106 may also be connected to the separator 105. For example, the protective member 106 is bonded to the first adjacent ring 107. Regardless of whether the protective member 106 is connected to the positive electrode 102 or the separator 105, it is sufficient that the protective member 106 can cover at least a portion of the inner edge 103.

[0041] Figure 4 The positive electrode 102 and positive electrode tab 109 of the first embodiment are shown. Figure 4 In the middle, the positive electrode 102 is in a flat state. Figure 4 (a) is a top view of the positive electrode 102. Figure 4 (b) is a front view of the positive electrode 102. (e.g.) Figure 4 As shown, in the first embodiment, the positive electrode 102 includes a positive current collector 112 and two positive active material layers 110, which are respectively disposed on both sides of the positive current collector 112. One of the positive active material layers 110 and the positive current collector 112 together define a tab groove 111, and a positive tab 109 is disposed in the tab groove 111 and welded to the positive current collector 112. Figure 4 As shown, the positive electrode tab 109 is approximately located in the middle of the positive electrode plate 102. The edge of the positive current collector 112 near the center of the cylindrical cell 101 is the first edge 113, and the edge of the positive active material layer 110 near the center of the cylindrical cell 101 is the second edge 114. The first edge 113 and the second edge 114 are flush, and the first edge 113 and the two second edges 114 together form the inner edge 103. Correspondingly, the protective member 106 can be bonded to the positive active material layer 110, that is, the protective member 106 is bonded to the surface of the positive active material layer 110 opposite to the positive current collector 112.

[0042] In some other embodiments not shown, the length of one of the positive electrode active material layers 110 may be shorter than that of the other positive electrode active material layer 110, with only one of the second edges 114 and the first edge 113 being flush. In this case, the flush first edge 113 and the second edge 114 together constitute the inner edge 103.

[0043] like Figure 5 As shown, in the first embodiment, the protective member 106 completely covers the inner edge 103. Compared to the case where the protective member 106 only covers a portion of the inner edge 103, the complete coverage of the inner edge 103 by the protective member 106 helps to further reduce the direct contact area between the inner edge 103 and the diaphragm 105, thereby further reducing the risk of the diaphragm 105 being damaged by the inner edge 103, and further reducing the risk of internal short circuit in the cylindrical cell 101.

[0044] To ensure that the protective element 106 completely covers the inner end edge 103, the protective element 106 may satisfy the following conditions: in the circumferential direction of the cylindrical cell 101, a portion of the protective element 106 protrudes beyond the inner end edge 103; in the axial direction of the cylindrical cell 101, the inner end edge 103 is located between the two ends of the protective element 106. For example, in Figure 5 In the middle, the two endpoints of the inner edge 103 on the axial direction of the cylindrical cell 101 are points A and B, respectively. Figure 5 Line segment AB represents the inner edge 103. A portion of the protective member 106 is located to the left of the inner edge 103 and connected to the positive electrode plate 102, while another portion of the protective member 106 is located to the right of the inner edge 103, protruding beyond it. The top of the protective member 106 is above the upper edge of the positive electrode plate 102, and the bottom of the protective member 106 is below the lower edge of the positive electrode plate 102. The inner edge 103 is entirely located between the top and bottom of the protective member 106.

[0045] The protective element 106 can be elastic. In this way, when the cylindrical cell 101 collapses towards the center, the elastic protective element 106 can buffer the impact, absorbing a portion of the force between the inner edge 103 and the separator 105. The separator 105 adjacent to the inner edge 103 experiences less pressure, which helps reduce the risk of damage to the separator 105, thereby reducing the risk of internal short circuit in the cylindrical cell 101. The surface of the protective element 106 facing away from the inner edge 103 is insulated. In this way, even if the separator 105 is damaged and the protective element 106 comes into contact with the negative electrode 104, the positive electrode 102 and the negative electrode 104 can still remain insulated, thus preventing internal short circuit in the cylindrical cell 101. Furthermore, since the protective element 106 is elastic and its edges are relatively soft (compared to the edges of the positive electrode 102), the edges of the protective element 106 are less likely to puncture the separator 105, which also helps to reduce the risk of internal short circuit when the cylindrical cell 101 collapses towards the center.

[0046] like Figure 6 As shown, the protective member 106 includes an adhesive layer 117, a buffer layer 116, and an insulating layer 115 stacked radially on top of each other in the cylindrical cell 101. The adhesive layer 117 is bonded to the positive electrode 102. The buffer layer 116 is elastic, thereby making the protective member 106 elastic in the radial direction of the cylindrical cell 101. The insulating layer 115 is provided to achieve "insulation of the side surface of the protective member 106 facing away from the inner end edge 103". The buffer layer 116 is disposed between the insulating layer 115 and the adhesive layer 117, and the side surface of the insulating layer 115 facing away from the inner end edge 103 is the side surface of the protective member 106 facing away from the inner end edge 103.

[0047] The adhesive layer 117 can be made of one of the following materials: acrylic acid, acrylate, silicone, polyurethane, epoxy resin, polyvinylidene fluoride, sodium carboxymethyl cellulose, or styrene-butadiene rubber. The buffer layer 116 can be made of rubber, and its elastic modulus is not less than 0.3 GPa and not greater than 5 GPa to ensure sufficient elasticity. The insulating layer 115 can be made of one of the following materials: polypropylene, polyethylene terephthalate, or polyimide.

[0048] The positive current collector 112 of the positive electrode 102 is usually made of aluminum foil, which makes the edge of the positive electrode 102 relatively hard or sharp. According to the materials of the various structural layers of the protective component 106 described above, the edge of the protective component 106 is more flexible than the edge of the positive electrode 102. The edge of the protective component 106 is less likely to puncture the separator 105, which also helps to reduce the risk of internal short circuit when the cylindrical cell 101 collapses towards the center.

[0049] In other embodiments not shown, the protective member 106 may also consist only of an adhesive layer 117 and a buffer layer 116, but the buffer layer 116 is both elastic and insulating. In this way, both the surface of the protective member 106 facing away from the inner edge 103 is insulated and the protective member 106 is elastic can be satisfied at the same time.

[0050] The thickness of the protective component 106 can be no less than 0.02 mm and no more than 0.1 mm. A thickness of no less than 0.02 mm prevents the protective component 106 from being too thin, thus avoiding excessive processing difficulty. A thickness of no more than 0.1 mm prevents the protective component 106 from being too thick, thus preventing uneven thickness or flatness in the cylindrical cell 101. Simultaneously, because the thickness of the protective component 106 is no more than 0.1 mm, the edge hardness of the protective component 106 will not be too high, making it less likely to puncture the separator 105. The ratio of the thickness of the insulating layer 115 to the thickness of the protective component 106 is no less than 0.3 to ensure that the protective component 106 has sufficient strength, facilitating its attachment to the positive electrode plate 102 during the production of the cylindrical cell 101.

[0051] As described above, the protective element 106 is bonded to the positive electrode active material layer 110. Accordingly, a portion of the positive electrode active material layer 110 is shielded by the protective element 106. In this case, the protective element 106 can have pores that allow lithium ions to pass through, thus reducing the area of ​​the positive electrode active material layer 110 actually shielded by the protective element 106, thereby increasing the capacity and energy density of the cylindrical cell 101 (compared to the case where the protective element 106 has no pores at all). More specifically, each of the adhesive layer 117, buffer layer 116, and insulating layer 115 has pores. The porosity of the protective element 106 can be no less than 10% and no more than 40%. The porosity of the protective element 106 refers to the ratio of the volume of the pores to the total volume of the protective element 106; the higher the porosity, the more lithium ions can pass through the protective element 106. A porosity of no less than 10% allows the protective element 106 to effectively improve the capacity and energy density of the cylindrical cell 101. A porosity of no more than 40% is beneficial to prevent the protective component 106 from being insufficient in protecting the inner edge 103.

[0052] As described above, in the first embodiment, only one protective member 106 is provided, and the protective member 106 is located inside the inner edge 103. However, in other embodiments, the protective member 106 may be arranged in other ways. For example, the protective member 106 may also be arranged in other ways. Figures 7 to 10 The settings are shown below.

[0053] like Figure 7 As shown, in the second embodiment, three protective members 106 are provided. Furthermore, in the radial direction of the cylindrical cell 101 (which may correspond to perpendicular to...), Figure 7 (In the orientation of the paper), all protective elements 106 are located on the same side of the inner edge. Adjacent protective elements 106 are spaced apart, with a portion of the inner edge 103 covered by a protective element 106, and the other portion of the inner edge 103 not covered by any protective element 106. Of course, based on Figure 7 In the embodiment shown, the number of protective components 106 can also be set to two or more, and the number of protective components 106 is not limited to three.

[0054] like Figure 8 As shown, in the third embodiment, only one protective member 106 is provided. Although a portion of the protective member 106 protrudes beyond the inner end edge 103 in the circumferential direction of the cylindrical cell 101, the length of the protective member 106 in the axial direction of the cylindrical cell 101 is less than the length of the inner end edge 103. Therefore, a portion of the inner end edge 103 is exposed outside the protective member 106.

[0055] Comparing the first to third embodiments, the first embodiment (where the protective element 106 completely covers the inner edge 103) provides better protection for the inner edge 103, and the risk of internal short circuit when the cylindrical cell 101 collapses towards the center is lower. The second and third embodiments, on the other hand, are advantageous in reducing the area of ​​the protective element 106, thus saving costs.

[0056] like Figure 9 As shown, in the fourth embodiment, all protective elements 106 (one or more protective elements 106) are located on the outer side of the inner end edge 103 in the radial direction of the cylindrical cell 101. In the first embodiment, since the protective element 106 is located on the inner side of the inner end edge 103, the protective element 106 is mainly used to reduce the risk of the inner end edge 103 damaging the first adjacent ring 107 of the separator 105, thereby reducing the risk of the inner end edge 103 contacting and short-circuiting with the inner negative electrode 104. In the fourth embodiment, since the protective element 106 is located on the outer side of the inner end edge 103, the protective element 106 is mainly used to reduce the risk of the inner end edge 103 damaging the second adjacent ring 108 of the separator 105, thereby reducing the risk of the inner end edge 103 contacting and short-circuiting with the outer negative electrode 104.

[0057] like Figure 10 As shown, in the fifth embodiment, the cylindrical cell 101 includes at least two protective members 106. In the radial direction of the cylindrical cell 101, at least one protective member 106 is located inside the inner end edge 103, and at least one protective member 106 is located outside the inner end edge 103. Compared to the first or third embodiment, the fifth embodiment has a lower risk of damage to the first adjacent ring 107 and the second adjacent ring 108 at the inner end edge 103, and a lower risk of internal short circuit when the cylindrical cell 101 collapses towards the center. Furthermore, compared to the fifth embodiment, the area of ​​the positive electrode active material layer 110 shielded by the protective member 106 in the first or third embodiment is smaller, resulting in higher capacity and energy density for the cylindrical cell 101.

[0058] Furthermore, based on the fifth embodiment, the two protective members 106 located on different sides of the inner edge 103 can be bonded together. This allows the two protective members 106 to wrap around the inner edge 103, thereby improving the protection effect on the inner edge 103 and reducing the risk of internal short circuit when the cylindrical cell 101 collapses towards the center.

[0059] It should be noted that the so-called reduction in the risk of internal short circuit when the cylindrical cell 101 collapses towards the center, as claimed in this application, is relative to... Figure 1 This refers to the prior art. For the first embodiment, the risk of its second adjacent ring 108 being damaged by the inner edge 103 is... Figure 1The existing technology shown is essentially the same, but in the first embodiment, the risk of the first adjacent ring 107 being destroyed by the inner edge 103 is obviously lower. Figure 1 The prior art shown. Therefore, in summary, the risk of an internal short circuit when the cylindrical cell 101 of the first embodiment collapses towards the center is lower than that of the prior art. Figure 1 The prior art is shown. Similarly, for the fourth embodiment, the risk of its first adjacent ring 107 being destroyed by the inner end edge 103 is similar to... Figure 1 The prior art shown is comparable, but in the fourth embodiment, the risk of the second adjacent ring 108 being destroyed by the inner edge 103 is obviously lower. Figure 1 The prior art shown. Therefore, in summary, the risk of an internal short circuit when the cylindrical cell 101 of the fourth embodiment collapses towards the center is lower than that of the prior art. Figure 1 The prior art shown.

[0060] The cylindrical cell 101 mentioned above can be used in cylindrical batteries, which also include a cylindrical casing, and the cylindrical cell 101 is disposed inside the casing.

[0061] In the description of this utility model, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this utility model. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

Claims

1. A cylindrical battery cell, characterized in that, It includes a positive electrode, a negative electrode, and a separator, wherein the separator separates the positive electrode and the negative electrode, and the edge of the positive electrode near the center of the cylindrical cell is the inner edge of the positive electrode. The cylindrical cell also includes one or more protective components, which are connected to the positive electrode or the separator, and the protective components cover at least a portion of the inner edge.

2. The cylindrical battery cell according to claim 1, characterized in that, The protective component completely covers the inner edge.

3. The cylindrical battery cell according to claim 2, characterized in that, In the circumferential direction of the cylindrical battery cell, a portion of the protective member protrudes beyond the inner end edge; Along the axial direction of the cylindrical battery cell, the inner end edge is located between the two ends of the protective member.

4. The cylindrical battery cell according to claim 1, characterized in that, In the radial direction of the cylindrical battery cell, the protective member is located outside the inner end edge; Alternatively, in the radial direction of the cylindrical cell, the protective member is located inside the inner end edge; Alternatively, the cylindrical cell may include at least two of the protective elements, wherein at least one of the protective elements is located inside the inner edge of the inner end and at least one of the protective elements is located outside the inner edge of the inner end in the radial direction of the cylindrical cell.

5. The cylindrical battery cell according to claim 1, characterized in that, The protective element is elastic; and / or, the surface of the protective element opposite to the inner edge is insulated.

6. The cylindrical battery cell according to claim 1, characterized in that, The protective component includes: An adhesive layer is bonded to the positive electrode sheet; A buffer layer, wherein the buffer layer is elastic; An insulating layer, a buffer layer, and an adhesive layer are stacked on top of each other in the radial direction of the cylindrical battery cell, and the buffer layer is disposed between the insulating layer and the adhesive layer.

7. The cylindrical battery cell according to claim 6, characterized in that, The adhesive layer is made of one of the following materials: acrylic acid, acrylate, silicone, polyurethane, epoxy resin, polyvinylidene fluoride, sodium carboxymethyl cellulose, and styrene-butadiene rubber. And / or, the elastic modulus of the material of the buffer layer is not less than 0.3 GPa and not greater than 5 GPa; And / or, the material of the insulating layer is one of polypropylene, polyethylene terephthalate, and polyimide.

8. The cylindrical battery cell according to claim 6, characterized in that, The ratio of the thickness of the insulating layer to the thickness of the protective component is not less than 0.

3.

9. The cylindrical battery cell according to claim 1, characterized in that, The thickness of the protective component is not less than 0.02 mm and not more than 0.1 mm; And / or, the positive electrode sheet includes a positive electrode active material layer, the protective component is bonded to the positive electrode active material layer, and the porosity of the protective component is not less than 10% and not more than 40%.

10. A cylindrical battery, characterized in that, It includes a housing and a cylindrical battery cell as claimed in any one of claims 1 to 9, wherein the housing is cylindrical and the cylindrical battery cell is located inside the housing.

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