Roll core structure and lithium ion battery

Abstract

The embodiment of the utility model provides a roll core structure and a lithium ion battery, and relates to the technical field of batteries. The roll core structure comprises a first pole piece; the first pole piece is provided with a first pole arc-shaped section in the bending area of the roll core structure, the first pole arc-shaped section is provided with at least one first protection part, and the first protection part corresponds to one end corner of the shell so as to prevent the first pole piece from puncturing the end corner of the shell. According to the lithium ion battery, at least one first protection part is arranged on the first pole arc-shaped section of the first pole piece, and the first protection part corresponds to one end corner of the shell, so that the first protection part can prevent the first pole piece from puncturing the end corner of the shell after expansion in the cycle process of the lithium ion battery, the end corner of the shell can be protected, and the service life of the lithium ion battery is prolonged. And the safety performance of the lithium ion battery is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a winding core structure and a lithium ion battery. Background Art

[0002] Lithium-ion batteries are highly favored due to their excellent characteristics such as high energy density, long cycle life, and environmental friendliness. With the large-scale application of lithium-ion batteries, the performance and manufacturing process of lithium-ion batteries have been continuously explored and improved, especially the cycle life and safety performance of lithium-ion batteries.

[0003] In the related art, the energy density is improved by reducing the gap between the core structure and the packaging shell to improve the utilization rate of the internal space of the packaging shell.

[0004] However, during the cycle of lithium-ion batteries, the expansion of the pole pieces can puncture the corners of the shell, reducing the safety performance of lithium-ion batteries. Utility Model Content

[0005] The embodiments of the utility model provide a winding core structure and a lithium-ion battery to solve the problem that during the cycle of the lithium-ion battery, the expansion of the pole piece may puncture the end corner of the shell, thereby reducing the safety performance of the lithium-ion battery.

[0006] On the one hand, an embodiment of the utility model provides a winding core structure, which is encapsulated in a housing of a lithium-ion battery, and includes a first pole piece located at the outermost side of the winding core structure;

[0007] The winding core structure has a straight area and a curved area, the first pole piece has a first pole arc segment in the curved area, at least one first protection portion is provided on the first pole arc segment, and the first protection portion corresponds to an end angle of the shell;

[0008] The first pole piece has a first pole straight section connected to the first pole arc section in the straight region, and the first protection portion is at least partially located on the first pole straight section.

[0009] In a possible implementation manner, a first protection portion is provided at least at one end of the first arc-shaped segment in the width direction of the lithium-ion battery.

[0010] In a possible embodiment, the first pole piece includes, in an extending direction from the tail end of the winding core structure toward the starting end thereof, a first pole straight segment 1, a first pole arc segment 1, a first pole straight segment 2, a first pole arc segment 2 and a first pole straight segment 3 connected in sequence, the first pole straight segment 1 is parallel to the first pole straight segment 2, and the first pole arc segment 1 and the first pole arc segment 2 are respectively located on both sides of the first pole straight segment 1 in the length direction of the lithium-ion battery;

[0011] The first pole arc segment 1 is provided with a first protection portion at at least one end in the width direction of the lithium ion battery; and / or the first pole arc segment 2 is provided with a first protection portion at at least one end in the width direction of the lithium ion battery.

[0012] In a possible embodiment, it also includes a second pole piece, which has a second pole arc segment in the bending area, and at least one second protective portion is arranged on the second pole arc segment, and the projection of the first protective portion on the first pole arc segment adjacent to the second pole arc segment on the second pole arc segment is located on the inner side of the edge of the second protective portion on the second pole arc segment.

[0013] In a possible implementation, the first pole piece further includes a first pole arc segment 3, a first pole straight segment 4 and a first pole arc segment 4 connected in sequence in the extension direction from the tail end of the winding core structure toward the starting end thereof, the first pole arc segment 3 is connected to the first pole straight segment 3, the second pole piece further includes a second pole arc segment 1, a second pole straight segment 1 and a second pole arc segment 2 connected in sequence in the extension direction from the tail end of the winding core structure toward the starting end thereof, the second pole arc segment 1 and the first pole arc segment 3 are adjacently arranged, and the second pole arc segment 2 and the first pole arc segment 4 are adjacently arranged;

[0014] The first pole arc segment three and the first pole arc segment four are each provided with a first protection portion at both ends in the width direction of the lithium ion battery, and the second pole arc segment one and the second pole arc segment two are each provided with a second protection portion at both ends in the width direction of the lithium ion battery.

[0015] In a possible implementation manner, the first protection portion is a first arc-shaped notch, and in the winding direction of the winding core structure, the difference between the width of each first arc-shaped notch and the circumference of the corresponding first pole arc segment is 3 to 10 mm;

[0016] The depth of each of the first arc-shaped notches in the width direction of the lithium-ion battery is greater than 2 mm, and the depth of the first arc-shaped notches is less than 5 mm.

[0017] In a possible implementation, the first protection portion is a first arc-shaped notch, the second protection portion is a second arc-shaped notch, and in the winding direction of the winding core structure, the difference between the width of the first arc-shaped notch and the width of the second arc-shaped notch is 0.5 to 2 mm;

[0018] In the width direction of the lithium-ion battery, the difference between the depth of the first arc-shaped notch and the depth of the second arc-shaped notch is 0.5 to 2 mm.

[0019] In a possible implementation manner, the first protection portion is a buffer layer, the first protection portion is attached to the corresponding first pole arc segment, and in the winding direction of the winding core structure, the difference between the width of the first protection portion and the circumference of the corresponding first pole arc segment is 3 to 10 mm;

[0020] The first protection portion exceeds the first arc segment by 1 to 5 mm in the width direction of the lithium-ion battery.

[0021] In a possible implementation manner, the first pole arc segment is provided with two connected first protection parts in the width direction of the lithium-ion battery, and the difference between the length of the two first protection parts and the width of the first pole piece in the width direction of the lithium-ion battery is 2 to 10 mm; or,

[0022] The first pole arc segment is provided with two first protection parts spaced apart in the width direction of the lithium-ion battery. In the width direction of the lithium-ion battery, the length of the first protection part is greater than or equal to 8 mm, and the difference between the length of the first protection part and the width of the first pole piece is less than or equal to 10 mm.

[0023] On the other hand, an embodiment of the present invention provides a winding core structure, including the winding core structure as described above.

[0024] The embodiment of the utility model provides a winding core structure and a lithium-ion battery, including a first pole piece; the first pole piece has a first pole arc segment in the bending area of ​​the winding core structure, and at least one first protection portion is arranged on the first pole arc segment, and the first protection portion corresponds to an end angle of the shell to prevent the first pole piece from piercing the end angle of the shell. By arranging at least one first protection portion on the first pole arc segment of the first pole piece, and the first protection portion corresponds to an end angle of the shell, during the circulation process of the lithium-ion battery, the first protection portion can prevent the first pole piece from piercing the end angle of the shell after expansion, thereby protecting the end angle of the shell and improving the safety performance of the lithium-ion battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0026] Figure 1 It is a schematic diagram of the structure of a lithium-ion battery in the related art;

[0027] Figure 2A schematic diagram of a winding core structure provided in Embodiment 1 of the present utility model;

[0028] Figure 3 A schematic diagram of the structure of the first pole piece provided in the first embodiment of the utility model;

[0029] Figure 4 for Figure 3 A schematic diagram of a first side of a first pole piece in FIG.

[0030] Figure 5 for Figure 3 A schematic diagram of a second side of the first pole piece in FIG.

[0031] Figure 6 A schematic diagram of the structure of the second pole piece provided in the first embodiment of the utility model;

[0032] Figure 7 for Figure 6 A schematic diagram of a first side of a second pole piece in FIG.

[0033] Figure 8 A schematic diagram of a winding core structure provided in the second embodiment of the present utility model;

[0034] Fig. 9 A schematic diagram of the structure of the first pole piece provided in the second embodiment of the utility model;

[0035] Fig.10 for Fig. 9 A schematic diagram of a first side of a first pole piece in FIG.

[0036] Fig.11 This is a schematic diagram of the structure of the first pole piece provided in Embodiment 3 of the present utility model.

[0037] Description of reference numerals:

[0038] 100- winding core structure; 10- first pole piece;

[0039] 110 - first electrode current collector; 120 - first electrode active material layer;

[0040] 101-first pole straight segment 1; 102-first pole arc segment 1;

[0041] 103-first pole straight segment 2; 104-first pole arc segment 2;

[0042] 105-first pole straight segment three; 106-first pole arc segment three;

[0043] 107-first pole straight segment four; 108-first pole arc segment four;

[0044] 20-second pole piece; 210-second pole current collector;

[0045] 220 - second pole active material layer; 201 - second pole arc segment 1;

[0046] 202-the second pole straight segment 1; 203-the second pole arc segment 2;

[0047] 30-first protection part; 40-second protection part;

[0048] 200-housing; 20a-end angle. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0050] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present utility model, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0051] In the present invention, unless otherwise clearly specified and limited, the terms "installation", "connection", "fixation" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0052] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0053] In the above description, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0054] As described in the background technology, Figure 1 As shown, during the cycle of the lithium-ion battery, the expansion of the positive electrode sheet of the core structure 100 will puncture the end corner 20a of the shell 200, reducing the safety performance of the lithium-ion battery. The inventors have found that the reason for this problem is that during the cycle of the lithium-ion battery, the negative electrode sheet of the core structure 100 expands in its width direction, and then drives the positive electrode sheet to expand in its width direction through the diaphragm, causing the edge of the positive electrode sheet to puncture the end corner 20a of the shell 200, reducing the safety performance of the lithium-ion battery.

[0055] In order to solve the above problems, an embodiment of the utility model provides a winding core structure and a lithium-ion battery, wherein a first pole piece located at the outermost side of the winding core structure has a first pole arc segment in the bending area of ​​the winding core structure, and at least one first protective portion is arranged on the first pole arc segment, and the first protective portion corresponds to an end corner of the shell. During the circulation process of the lithium-ion battery, the first protective portion can prevent the first pole piece from puncturing the end corner of the shell after expansion, thereby protecting the end corner of the shell and improving the safety performance of the lithium-ion battery.

[0056] In the present application, the shell is generally a structure such as an aluminum-plastic film, a transparent packaging film, etc., which can encapsulate the roll core to form a soft-pack lithium-ion battery cell.

[0057] The winding core structure and lithium-ion battery provided by the utility model embodiments are described in detail below in conjunction with specific embodiments.

[0058] like Figure 2 As shown, the present invention provides a winding core structure 100, which is encapsulated in a housing 200 of a lithium-ion battery (see Figure 1 The housing 200 has four corners 20a in the width direction of the lithium-ion battery.

[0059] A direct coordinate system is established for the lithium-ion battery. The X-axis direction is the length direction of the lithium-ion battery; the Y-axis direction is the width direction of the lithium-ion battery; and the Z-axis direction is the thickness direction of the lithium-ion battery.

[0060] The length direction of the core structure 100 is the same as the length direction of the lithium-ion battery, the width direction of the core structure 100 is the same as the width direction of the lithium-ion battery, the thickness direction of the core structure 100 is the same as the thickness direction of the lithium-ion battery, and the X-axis, Y-axis and Z-axis are perpendicular to each other.

[0061] The winding core structure 100 includes a first pole piece 10 (see Figure 3 As shown), the second pole piece 20 (see Figure 6 The first pole piece 10, the diaphragm and the second pole piece 20 are stacked together in sequence, and then wound from the starting end to the ending end to form a roll core structure 100 of the lithium-ion battery. It should be noted that the starting end of the first pole piece 10 and the second pole piece 20 is the starting end of the roll core structure 100, and the starting end of the roll core structure 100 is located on the inner side of the lithium-ion battery, and the ending end of the first pole piece 10 and the second pole piece 20 is the ending end of the roll core structure 100, and the ending end of the roll core structure 100 is located on the outer side of the lithium-ion battery. The winding direction of the roll core structure 100 is the extension direction from the starting end of the roll core structure 100 toward the ending end.

[0062] The core structure 100 has a straight region and a curved region. In the winding direction of the core structure 100, the straight portion is the straight region, and the curved portion is the curved region.

[0063] The first electrode sheet 10 is located at the outermost side of the winding core structure 100. The first electrode sheet 10 can be a positive electrode sheet or a negative electrode sheet. It can be understood that when the first electrode sheet 10 is a positive electrode sheet, the second electrode sheet 20 is a negative electrode sheet, and when the first electrode sheet 10 is a negative electrode sheet, the second electrode sheet 20 is a positive electrode sheet. In this embodiment, the first electrode sheet 10 is a positive electrode sheet, and the second electrode sheet 20 is a negative electrode sheet.

[0064] Figure 3 One side of the first pole piece 10 in the +K axis direction is a first side, and one side in the -K axis direction is a second side.

[0065] like Figures 3 to 5 As shown, the first electrode sheet 10 includes a first electrode current collector 110, and a first electrode active material layer 120 coated on two opposite sides of the first electrode current collector 110. In some examples, an aluminum foil or a composite current collector can be used as the first electrode current collector 110, and the composite current collector can include a polymer layer and two aluminum layers respectively located on opposite sides of the polymer layer.

[0066] The width direction of the first pole piece 10 is the same as the width direction of the lithium-ion battery.

[0067] The first pole piece 10 has a first pole arc segment in the bending area of ​​the winding core structure 100, and at least one first protective portion 30 is arranged on the first pole arc segment. The first protective portion 30 corresponds to an end corner 20a of the shell 200 to prevent the first pole piece 10 from piercing the end corner 20a of the shell 200.

[0068] The first pole piece 10 has a plurality of first pole arc segments and a plurality of first pole straight segments which are alternately connected after being wound.

[0069] After the first pole piece 10 is wound, the shape of the first pole arc segment is arc-shaped, and the shape of the first pole straight segment is straight-line-shaped.

[0070] The first pole piece 10 may be provided with at least one first protection portion 30 on one first pole arc segment, or may be provided with at least one first protection portion 30 on multiple first pole arc segments.

[0071] A first protection portion 30 corresponds to an end corner 20a of the shell 200. During the cycle of the lithium-ion battery, the first protection portion 30 can prevent the first pole piece 10 from expanding and piercing the end corner 20a of the shell 200, thereby protecting the end corner 20a of the shell 200 and improving the safety performance of the lithium-ion battery.

[0072] In a possible implementation, a first protection portion 30 is provided at least at one end of the first arc segment in the width direction of the lithium-ion battery.

[0073] Among them, the first protection portion 30 may be partially located on the first pole arc segment, and the other part may be located on the first pole straight segment, that is, the first protection portion 30 is at least partially located on the first pole straight segment, and it can be understood that the first protection portion 30 on the first pole arc segment may extend to the first pole straight segment connected to the first pole arc segment, thereby increasing the protection range of the first protection portion 30. In other embodiments, the first protection portion 30 may also be entirely disposed on the corresponding first pole arc segment.

[0074] Figures 3 to 5 The first pole piece 10 is a schematic diagram of being unfolded after being wound.

[0075] For example, Figures 3 to 5 As shown, the first pole piece 10 includes a first pole straight segment 101, a first pole arc segment 102, a first pole straight segment 103, a first pole arc segment 2 104 and a first pole straight segment 3 105 which are connected in sequence in the extending direction from the tail end of the winding core structure 100 toward its starting end. After the first pole piece 10 is wound, the first pole straight segment 101 is parallel to the first pole straight segment 103, and the first pole arc segment 102 and the first pole arc segment 2 104 are located on both sides of the first pole straight segment 101 in the length direction of the lithium-ion battery.

[0076] It should be noted that the extension direction of the tail end of the core structure 100 toward the starting end thereof is the opposite direction of the winding direction of the core structure 100 .

[0077] The first pole arc segment 1 102 is provided with a first protection portion 30 at least at one end in the width direction of the lithium-ion battery; and / or, the first pole arc segment 2 104 is provided with a first protection portion 30 at least at one end in the width direction of the lithium-ion battery. Specifically, in the first example, the first pole arc segment 1 102 can be provided with a first protection portion 30 at least at one end in the width direction of the lithium-ion battery. In the second example, the first pole arc segment 2 104 can be provided with a first protection portion 30 at least at one end in the width direction of the lithium-ion battery. In the third example, both the first pole arc segment 1 102 and the first pole arc segment 2 104 can be provided with a first protection portion 30 at least at one end in the width direction of the lithium-ion battery.

[0078] For example, Figure 4 and Figure 5 As shown, a first protection portion 30 is respectively provided at both ends of the first pole arc segment 102 in the width direction of the lithium ion battery, and a first protection portion 30 is respectively provided at both ends of the first pole arc segment 104 in the width direction of the lithium ion battery. The first protection portion 30 on the first pole arc segment 102 can extend to the first pole straight segment 101 and the first pole straight segment 103, and the first protection portion 30 on the first pole arc segment 104 can extend to the first pole straight segment 103 and the first pole straight segment 3 105, so that the two first protection portions 30 on the first pole arc segment 102 and the two first protection portions 30 on the first pole arc segment 104 can respectively correspond to the four end corners 20a of the shell 200, thereby preventing the first pole arc segment 102 and the first pole arc segment 104 of the first pole piece 10 from piercing the end corner 20a of the shell 200.

[0079] Further, the first protection portion 30 on the first pole arc segment 1 102 and the first pole arc segment 2 104 can both be a first notch.

[0080] The first notch may be formed by cutting the first pole piece 10 . It can be understood that the first notch is formed by cutting off a portion of the first pole piece 10 .

[0081] The shape of the first notch may be arc-shaped, square-shaped, or other shapes, as long as the first notch can prevent the first pole piece 10 from puncturing the end corner 20a of the shell 200 after expansion, thereby protecting the end corner 20a of the shell 200.

[0082] Exemplarily, the first notch is a first arc-shaped notch, and the first protection portions 30 on the first pole arc-shaped segment 1 102 and the first pole arc-shaped segment 2 104 are both first arc-shaped notches.

[0083] The shape of the first arc-shaped notch may be semicircular or semi-elliptical.

[0084] The difference between the width m1 of each first arc-shaped notch and the circumference of the corresponding first pole arc segment is 3 to 10 mm. It can be understood that the width m1 of the first arc-shaped notch is greater than the circumference of the corresponding first pole arc segment, so that the first arc-shaped notch is partially located on the first pole straight segment, which can increase the protection range of the first arc-shaped notch and can prevent the first pole piece 10 from piercing the end corner 20a of the shell 200 after expansion. Specifically, when the first protection portion 30 on the first pole arc segment 102 is the first arc-shaped notch, the difference between the width m1 of the first arc-shaped notch and the circumference of the first pole arc segment 102 is 3 to 10 mm, which can make the first arc-shaped notch partially located on the first pole straight segment 101 and the first pole straight segment 2 103, which can prevent the first pole arc segment 1 102 from piercing the end corner 20a of the shell 200 and reduce the possibility of the first pole straight segment 101 and the first pole straight segment 2 103 piercing the shell 200. When the first protection portion 30 on the first pole arc segment 104 can be a first arc-shaped notch, the difference between the width m1 of the first arc-shaped notch and the circumference of the first pole arc segment 104 is 3 to 10 mm, so that the first arc-shaped notch can be partially located on the first pole straight segment 103 and the first pole straight segment 105, which can prevent the first pole arc segment 104 from piercing the end corner 20a of the shell 200 and reduce the possibility of the first pole straight segment 103 and the first pole straight segment 105 piercing the shell 200.

[0085] The width m1 of the first arc-shaped notch is the width of the first arc-shaped notch in the winding direction of the winding core structure 100; Figure 4 and Figure 5 The distance between the leftmost and rightmost sides of the first arc-shaped notch can be regarded as the width m1 of the first arc-shaped notch.

[0086] The circumference of the first pole arc segment is the circumference of the first pole arc segment in the winding direction of the winding core structure 100. Figure 4 and Figure 5 The distance between the leftmost and rightmost sides of the first pole arc segment 102 can be regarded as the circumference of the first pole arc segment 102 , and the distance between the leftmost and rightmost sides of the first pole arc segment 104 can be regarded as the circumference of the first pole arc segment 104 .

[0087] In the width direction of the lithium-ion battery, the depth h1 of each first arc-shaped notch is greater than 2 mm, so that the first pole piece 10 can have sufficient expansion space in the width direction of the lithium-ion battery; the depth h1 of each first arc-shaped notch is less than 5 mm, which can avoid the notch being too large, resulting in greater loss of positive electrode active material, affecting capacity and reducing energy density.

[0088] The depth h1 of the first arc-shaped notch is the depth of the first arc-shaped notch in the width direction of the lithium-ion battery; Figure 4 and Figure 5 The distance between the uppermost side and the lowermost side of the first arc-shaped notch can be regarded as the depth h1 of the first arc-shaped notch.

[0089] Figure 6 One side of the second pole piece 20 in the +K axis direction is a first side, and one side in the −K axis direction is a second side. Figure 6 and Figure 7 The second pole piece 20 is a schematic diagram of being unfolded after being wound.

[0090] like Figure 6 and Figure 7 As shown, the second electrode sheet 20 includes a second electrode current collector 210 and a second electrode active material layer 220 coated on two opposite surfaces of the second electrode current collector 210 .

[0091] The width direction of the second pole piece 20 is the same as the width direction of the lithium-ion battery.

[0092] In a possible embodiment, the second pole piece 20 has a second pole arc segment in the bending area of ​​the winding core structure 100, and at least one second protection portion 40 is arranged on the second pole arc segment, and the projection of the first protection portion 30 on the first pole arc segment adjacent to the second pole arc segment on the second pole arc segment is located on the inner side of the edge of the second protection portion 40 on the second pole arc segment. The inner side of the edge of the second protection portion 40 refers to the side of the edge of the second protection portion 40 facing the second pole piece 20 (at Figure 7 In the embodiment, the side of the edge of the second protection portion 40 in the direction of the arrow in the second protection portion 40 is the inner side of the edge of the second protection portion 40). With such arrangement, when the first electrode sheet 10 is a positive electrode sheet and the second electrode sheet 20 is a negative electrode sheet, the edge of the negative electrode active material exceeds or wraps the edge of the positive electrode active material, thereby avoiding the problem that the positive electrode active material on the positive electrode sheet has no corresponding negative electrode active material, resulting in the release of lithium ions without the negative electrode receiving and lithium deposition.

[0093] Among them, Figure 4 and Figure 5As shown, the first pole piece 10 further includes the first pole arc segment 3 106, the first pole straight segment 4 107 and the first pole arc segment 4 108 connected in sequence in the extending direction from the tail end of the winding core structure 100 toward the starting end thereof, and the first pole straight segment 3 105 is connected to the first pole arc segment 3 106. It can be understood that, in the extending direction of the first pole piece 10 from the tail end of the winding core structure 100 toward the starting end thereof, the first pole straight segment 1 101, the first pole arc segment 1 102, the first pole straight segment 2 103, the first pole arc segment 2 104, the first pole straight segment 3 105, the first pole arc segment 3 106, the first pole straight segment 4 107 and the first pole arc segment 4 108 are connected in sequence.

[0094] After being wound, the second pole piece 20 has a plurality of second pole arc segments and a plurality of second pole straight segments which are alternately connected.

[0095] After the second pole piece 20 is wound, the shape of the second pole arc segment is arc-shaped, and the shape of the second pole straight segment is straight-line-shaped.

[0096] For example, Figure 6 and Figure 7 As shown, the second pole piece 20 includes a second pole arc segment 1 201, a second pole straight segment 1 202 and a second pole arc segment 2 203 connected in sequence in the extension direction from the tail end of the winding core structure 100 toward its starting end. The second pole arc segment 1 201 and the first pole arc segment 3 106 are adjacently arranged, and the second pole arc segment 2 203 and the first pole arc segment 4 108 are adjacently arranged.

[0097] In the winding core structure 100, in the length direction of the lithium-ion battery, the second pole arc segment 1 201 is located between the first pole arc segment 1 102 and the first pole arc segment 3 106, and the second pole arc segment 2 203 is located between the first pole arc segment 2 104 and the first pole arc segment 4 108.

[0098] The first pole arc segment 1 102, the first pole arc segment 2 104, the first pole arc segment 3 106 and the first pole arc segment 4 108 are each provided with a first protection portion 30 at both ends in the width direction of the lithium ion battery, and the second pole arc segment 1 201 and the second pole arc segment 2 203 are each provided with a second protection portion 40 at both ends in the width direction of the lithium ion battery.

[0099] The projection of the first protection portion 30 on the first pole arc segment 1 102 and the first pole arc segment 3 106 on the second pole arc segment 1 201 is located inside the edge of the second protection portion 40 on the second pole arc segment 1 201 .

[0100] The projection of the first protection portion 30 on the first pole arc segment 2 104 and the first pole arc segment 4 108 on the second pole arc segment 203 is located inside the edge of the second protection portion 40 on the second pole arc segment 203 .

[0101] In a possible implementation, Figures 3 to 7 As shown, the first protection portion 30 is a first arc-shaped notch, and the second protection portion 40 is a second arc-shaped notch. In the winding direction of the core structure 100, the width m1 of the first arc-shaped notch is greater than the width m2 of the second arc-shaped notch, and the difference between the width m1 of the first arc-shaped notch and the width m2 of the second arc-shaped notch is 0.5 to 2 mm; in the width direction of the lithium-ion battery, the depth h1 of the first arc-shaped notch is greater than the depth h2 of the second arc-shaped notch, and the difference between the depth h1 of the first arc-shaped notch and the depth h2 of the second arc-shaped notch is 0.5 to 2 mm, so that the projection of the first protection portion 30 on the first pole arc segment adjacent to the second pole arc segment on the second pole arc segment is located on the inner side of the edge of the second protection portion 40 on the second pole arc segment.

[0102] The width m2 of the second arc-shaped notch is the width of the second arc-shaped notch in the winding direction of the winding core structure 100; Figure 7 The distance between the leftmost and rightmost sides of the second arc-shaped notch can be regarded as the width m2 of the second arc-shaped notch.

[0103] The depth h2 of the second arc-shaped notch is the depth of the second arc-shaped notch in the width direction of the lithium-ion battery; Figure 7 The distance between the uppermost side and the lowermost side of the second arc-shaped notch can be regarded as the depth h2 of the second arc-shaped notch.

[0104] The second arc-shaped notch can be formed by cutting the second pole piece 20 . It can be understood that the second arc-shaped notch is formed by cutting off a portion of the second pole piece 20 .

[0105] The core structure 100 in the second embodiment differs from the core structure 100 in the first embodiment in that the first protection portion 30 of the first pole piece 10 in the core structure 100 in the second embodiment is a buffer layer, and the second pole piece 20 is not provided with the second protection portion 40 .

[0106] like Figures 8 to 10 As shown, the first protection portion 30 is a buffer layer, and the buffer layer is attached to the corresponding first pole arc segment.

[0107] The buffer layer may be adhesive tape, for example, rubber adhesive tape, acrylic adhesive tape, polypropylene adhesive tape or SIS (Styrene-Isoprene-Styrene) adhesive tape, etc., which are not limited here. The thickness of the adhesive tape may be 6 to 20 um, preferably 10 to 16 um.

[0108] In other embodiments, the buffer layer may also be a glue layer, for example, a rubber glue layer, an acrylic glue layer, a polypropylene glue layer or a SIS (Styrene-Isoprene-Styrene) glue layer, etc., which is not limited here. The thickness of the glue layer may be 4 to 20 um, preferably 6 to 12 um.

[0109] A buffer layer is respectively disposed at both ends of the first arc segment 102 in the width direction of the lithium-ion battery, and a buffer layer is respectively disposed at both ends of the first arc segment 2 104 in the width direction of the lithium-ion battery.

[0110] The width m3 of the buffer layer is greater than the circumference of the corresponding first pole arc segment, and the difference between the width m3 of the buffer layer and the circumference of the corresponding first pole arc segment is 3 to 10 mm. In this way, the first protection portion 30 on the first pole arc segment can extend to the first pole straight segment connected to the first pole arc segment, which can increase the protection range of the first protection portion 30.

[0111] The width m3 of the buffer layer is the width of the buffer layer in the winding direction of the core structure 100. Fig.10 and Fig.11 The distance between the leftmost and rightmost sides of the middle buffer layer can be regarded as the width m3 of the buffer layer.

[0112] The circumference of the first pole arc segment is the circumference of the first pole arc segment in the winding direction of the winding core structure 100. Fig.10 and Fig.11 The distance between the leftmost and rightmost sides of the first pole arc segment 102 can be regarded as the circumference of the first pole arc segment 102 , and the distance between the leftmost and rightmost sides of the first pole arc segment 104 can be regarded as the circumference of the first pole arc segment 104 .

[0113] Specifically, in the winding direction of the winding core structure 100, the width m3 of the buffer layer on the first pole arc segment 102 is greater than the circumference of the first pole arc segment 102, and the difference between the width m3 of the buffer layer on the first pole arc segment 102 and the circumference of the first pole arc segment 102 is 3 to 10 mm. In this way, the buffer layer on the first pole arc segment 102 can be extended to the first pole straight segment 101 and the first pole straight segment 2 103.

[0114] The width m3 of the buffer layer on the first pole arc segment 104 is greater than the circumference of the first pole arc segment 104, and the difference between the width m3 of the buffer layer on the first pole arc segment 104 and the circumference of the first pole arc segment 104 is 3-10 mm. In this way, the buffer layer on the first pole arc segment 104 can be extended to the first pole straight segment 103.

[0115] The length S of the buffer layer exceeding the first pole arc segment in the width direction of the lithium-ion battery is 1 to 5 mm, so that the buffer layer can expose the first pole piece 10 in the width direction of the lithium-ion battery, and the exposed portion of the buffer layer can be attached to the diaphragm of the winding core structure, and the exposed portion is flush with the diaphragm in the width direction of the lithium-ion battery or exceeds the diaphragm in the width direction of the lithium-ion battery. In this way, the risk of the buffer layer failing to cover the edge of the first pole current collector 110 due to excessive expansion of the first pole piece 10 can be avoided, and the buffer layer is attached to the diaphragm to prevent the buffer layer from falling off or folding.

[0116] It should be noted that, in the width direction of the lithium-ion battery, the diaphragm exceeds the first pole piece 10 , that is, the diaphragm exposes the first pole piece 10 .

[0117] like Fig.10 As shown, the first pole arc segment may have two connected buffer layers in the width direction of the lithium-ion battery, that is, the two buffer layers of the first pole arc segment in the width direction of the lithium-ion battery are formed in one piece. In the width direction of the lithium-ion battery, the length of the two buffer layers is greater than the width U of the first pole piece 10, and the difference between the length of the two buffer layers and the width U of the first pole piece 10 is 2 to 10 mm. In this embodiment, in the width direction of the lithium-ion battery, the length of the two buffer layers is T1.

[0118] In other embodiments, Fig.11 As shown, the first pole arc segment is provided with two spaced-apart buffer layers in the width direction of the lithium-ion battery, that is, the two buffer layers are not connected, and in the width direction of the lithium-ion battery, the length T2 of the buffer layer is greater than or equal to 8 mm, and the difference between the length T2 of the buffer layer and the width U of the first pole piece 10 is less than or equal to 10 mm.

[0119] An embodiment of the utility model provides a lithium-ion battery, comprising a roll core structure.

[0120] Among them, the core structure in this embodiment is the same as the core structure provided in any of the above embodiments, and can bring the same or similar technical effects, which will not be described one by one here, and the details can be referred to the description of the above embodiments.

[0121] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the utility model.

Claims

1. A roll core structure, encapsulated in a lithium-ion battery housing, characterized in that: comprising a first pole piece located at the outermost side of the winding core structure; The winding core structure has a straight area and a curved area, the first pole piece has a first pole arc segment in the curved area, at least one first protection portion is provided on the first pole arc segment, and the first protection portion corresponds to an end angle of the shell; The first pole piece has a first pole straight section connected to the first pole arc section in the straight region, and the first protection portion is at least partially located on the first pole straight section.

2. The winding core structure according to claim 1, characterized in that: The first arc segment is provided with a first protection portion at at least one end thereof in the width direction of the lithium-ion battery.

3. The winding core structure according to claim 2, characterized in that: The first pole piece includes a first pole straight section 1, a first pole arc section 1, a first pole straight section 2, a first pole arc section 2 and a first pole straight section 3 connected in sequence in the extending direction from the tail end of the winding core structure toward the starting end thereof, the first pole straight section 1 is parallel to the first pole straight section 2, and the first pole arc section 1 and the first pole arc section 2 are respectively located on both sides of the first pole straight section 1 in the length direction of the lithium ion battery; The first pole arc segment 1 is provided with a first protection portion at at least one end in the width direction of the lithium ion battery; and / or the first pole arc segment 2 is provided with a first protection portion at at least one end in the width direction of the lithium ion battery.

4. The winding core structure according to claim 2, characterized in that: It also includes a second pole piece, which has a second pole arc segment in the bending area, and at least one second protective portion is arranged on the second pole arc segment, and the projection of the first protective portion on the first pole arc segment adjacent to the second pole arc segment on the second pole arc segment is located on the inner side of the edge of the second protective portion on the second pole arc segment.

5. The winding core structure according to claim 4, characterized in that: The first pole piece further includes a first pole arc segment 3, a first pole straight segment 4 and a first pole arc segment 4 connected in sequence in the extending direction from the tail end of the winding core structure toward the starting end thereof, the first pole arc segment 3 is connected to the first pole straight segment 3, the second pole piece further includes a second pole arc segment 1, a second pole straight segment 1 and a second pole arc segment 2 connected in sequence in the extending direction from the tail end of the winding core structure toward the starting end thereof, the second pole arc segment 1 and the first pole arc segment 3 are adjacently arranged, and the second pole arc segment 2 and the first pole arc segment 4 are adjacently arranged; The first pole arc segment three and the first pole arc segment four are each provided with a first protection portion at both ends in the width direction of the lithium ion battery, and the second pole arc segment one and the second pole arc segment two are each provided with a second protection portion at both ends in the width direction of the lithium ion battery.

6. The winding core structure according to any one of claims 1 to 5, characterized in that: The first protection portion is a first arc-shaped notch, and in the winding direction of the winding core structure, the difference between the width of each first arc-shaped notch and the circumference of the first pole arc segment corresponding thereto is 3 to 10 mm; The depth of each of the first arc-shaped notches in the width direction of the lithium-ion battery is greater than 2 mm, and the depth of the first arc-shaped notches is less than 5 mm.

7. The winding core structure according to claim 4 or 5, characterized in that: The first protection portion is a first arc-shaped notch, the second protection portion is a second arc-shaped notch, and in the winding direction of the winding core structure, the difference between the width of the first arc-shaped notch and the width of the second arc-shaped notch is 0.5 to 2 mm; In the width direction of the lithium-ion battery, the difference between the depth of the first arc-shaped notch and the depth of the second arc-shaped notch is 0.5 to 2 mm.

8. The winding core structure according to any one of claims 1 to 3, characterized in that: The first protection portion is a buffer layer, and the first protection portion is attached to the corresponding first pole arc segment. In the winding direction of the winding core structure, the difference between the width of the first protection portion and the circumference of the corresponding first pole arc segment is 3 to 10 mm; The first protection portion exceeds the first arc segment by 1 to 5 mm in the width direction of the lithium-ion battery.

9. The winding core structure according to claim 8, characterized in that: The first pole arc segment is provided with two connected first protection parts in the width direction of the lithium ion battery, and the difference between the length of the two first protection parts and the width of the first pole piece in the width direction of the lithium ion battery is 2 to 10 mm; or, The first pole arc segment is provided with two first protection parts spaced apart in the width direction of the lithium-ion battery. In the width direction of the lithium-ion battery, the length of the first protection part is greater than or equal to 8 mm, and the difference between the length of the first protection part and the width of the first pole piece is less than or equal to 10 mm.

10. A lithium ion battery, characterized in that: The invention comprises the winding core structure as described in any one of claims 1 to 9.

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