Roll core structure and lithium ion battery

Abstract

The embodiment of the invention provides a roll core structure and a lithium ion battery, and relates to the technical field of lithium ion batteries. The roll core structure comprises a first pole piece, a diaphragm and a second pole piece which are formed by winding; and a first soft tab part and a second soft tab part which are arranged at an interval are arranged on the current collector of the first pole piece. When the roll core structure is in a low-temperature environment, the first soft tab part and the second soft tab part are electrically connected with the first power supply respectively, and the first pole piece can serve as a heating resistor to heat the roll core structure, so that the temperature of the roll core structure is increased, and the problem of lithium precipitation of the lithium ion battery when the lithium ion battery is charged at a low temperature and a high rate can be avoided; and the cycle life of the lithium ion battery is prolonged.

Description

Technical Field

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

[0002] Lithium-ion batteries are highly favored for their excellent characteristics such as high energy density, long cycle life, and environmental friendliness. With the large-scale application of lithium-ion batteries, higher requirements are put forward for the energy density, fast charging capability, and charge and discharge rate of lithium-ion batteries, that is, fast charging at a high rate at low temperature, shortening the charging time, and improving the charging efficiency.

[0003] In the related art, lithium-ion batteries use low-temperature electrolytes to improve the charge and discharge capacity retention rate of lithium batteries at low temperatures.

[0004] However, lithium-ion batteries will still release lithium when charged at a high rate at low temperature, which reduces the cycle life of lithium-ion batteries. Summary of the invention

[0005] The embodiments of the present invention provide a roll core structure and a lithium-ion battery to solve the problem that lithium ions are still deposited in the lithium-ion battery under low-temperature and high-rate charging state, thereby reducing the cycle life of the lithium-ion battery.

[0006] On the one hand, an embodiment of the present invention provides a winding core structure, including a first pole piece, a diaphragm and a second pole piece formed by winding;

[0007] The current collector of the first pole piece is provided with a first soft pole ear portion and a second soft pole ear portion which are spaced apart from each other;

[0008] A projection of the first soft electrode ear portion in the thickness direction of the winding core structure does not overlap with a projection of the second soft electrode ear portion.

[0009] In a possible implementation manner, a pole tab groove is provided on the active material layer of the second pole piece, a second pole tab is provided in the pole tab groove, and the second pole tab is electrically connected to the current collector of the second pole piece;

[0010] The first soft pole ear portion, the second soft pole ear portion and the second pole ear are arranged at intervals in the width direction of the winding core structure;

[0011] In a possible implementation manner, in the height direction of the winding core structure, the first soft pole ear portion, the second soft pole ear portion, and the second pole ear are located on the same side of the winding core structure.

[0012] In a possible implementation manner, the first soft electrode ear portion includes a plurality of first soft electrode ears, the projection area of ​​the first soft electrode ears in the thickness direction of the winding core structure is a first area, and the overlapping area of ​​the projections of the plurality of first soft electrode ears in the thickness direction of the winding core structure is greater than or equal to 3 / 5 of the first area;

[0013] The second soft pole ear portion includes multiple second soft pole ears, the projection area of ​​the second soft pole ears in the thickness direction of the winding core structure is a second area, and the overlapping area of ​​the projections of the multiple second soft pole ears in the thickness direction of the winding core structure is greater than or equal to 3 / 5 of the second area.

[0014] In a possible implementation manner, in the width direction of the winding core structure, a minimum interval between the first soft pole ear closest to the second soft pole ear portion and the second soft pole ear closest to the first soft pole ear portion is 2 to 10 mm.

[0015] In a possible implementation manner, the width of the first soft electrode tab in the width direction of the winding core structure is equal to the width of the second soft electrode tab in the width direction of the winding core structure.

[0016] In a possible implementation manner, the number of the first soft electrode tabs is the same as the number of the second soft electrode tabs; or, the number of the first soft electrode tabs is different from the number of the second soft electrode tabs.

[0017] In a possible embodiment, the winding core structure has a central axis, and in the thickness direction of the winding core structure, the multiple first soft pole ears of the first soft pole ear portion are located on one side of the central axis; or, in the thickness direction of the winding core structure, the multiple first soft pole ears of the first soft pole ear portion are respectively located on both sides of the central axis.

[0018] In a possible embodiment, the winding core structure has a central axis, and in the thickness direction of the winding core structure, each second soft pole ear of the second soft pole ear portion is located on one side of the central axis; or, in the thickness direction of the winding core structure, each second soft pole ear of the second soft pole ear portion is located on both sides of the central axis.

[0019] In a possible implementation manner, a plurality of bending lines are formed during the winding process of the first pole piece, and in the winding direction of the winding core structure, the plurality of bending lines separate the first pole piece into a plurality of separation segments;

[0020] Each first soft pole ear of the first soft pole ear portion and each second soft pole ear of the second soft pole ear portion are both on adjacent said partition segments; or each first soft pole ear of the first soft pole ear portion and each second soft pole ear of the second soft pole ear portion are both on non-adjacent said partition segments.

[0021] In a possible implementation manner, the first pole piece includes a first section, a second section, and a third section connected in sequence, the first soft pole ear portion is located in the first section, and the second soft pole ear portion is located in the third section.

[0022] In a possible implementation manner, the plurality of first soft pole tabs of the first soft pole tab portion are welded to the first hard pole tab, and the plurality of second soft pole tabs of the second soft pole tab portion are welded to the second hard pole tab.

[0023] In a possible implementation manner, the first pole piece includes a single-sided region and a double-sided region connected to each other, a first active material layer is disposed on one side of the current collector of the single-sided region, and the first active material layer is disposed on both sides of the current collector of the double-sided region;

[0024] The first soft pole ear portion is located in the double-sided area and / or the single-sided area, and the second soft pole ear portion is located in the double-sided area and / or the single-sided area.

[0025] On the other hand, an embodiment of the present invention provides a lithium-ion battery, comprising the roll core structure as described above.

[0026] An embodiment of the present invention provides a winding core structure and a lithium-ion battery. When the winding core structure is in a low-temperature environment, a first soft pole ear portion and a second soft pole ear portion are arranged at intervals on the current collector of the first pole piece, and the first soft pole ear portion and the second soft pole ear portion are electrically connected to a first power source, respectively. The first pole piece can act as a heating resistor to heat the winding core structure, so that the temperature of the winding core structure increases, thereby avoiding the problem of lithium plating when the lithium-ion battery is charged at a low temperature and a large rate, thereby improving the cycle life of the lithium-ion battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0028] Figure 1 A cross-sectional schematic diagram of a winding core structure provided by an embodiment of the present invention;

[0029] Figure 2 A schematic structural diagram of a first pole piece provided by an embodiment of the present invention;

[0030] Figure 3 A schematic structural diagram of a second first pole piece provided in an embodiment of the present invention;

[0031] Figure 4 A schematic structural diagram of a second first pole piece provided in an embodiment of the present invention;

[0032] Figure 5 for Figure 1 A schematic top view of a core structure of the type shown in FIG.

[0033] Figure 6 for Figure 1 Schematic diagram of the left view of the core structure of the scroll.

[0034] Description of reference numerals:

[0035] 10- first pole piece;

[0036] 10a-double-sided area;

[0037] 10b - single-sided area;

[0038] 10c - empty foil area;

[0039] 11- first soft pole ear;

[0040] 111- first soft pole ear;

[0041] 12- second soft pole ear;

[0042] 121- second soft pole ear;

[0043] 20- second pole piece;

[0044] 21- second pole lug;

[0045] 30 - diaphragm;

[0046] 31-first hard tab;

[0047] 32-Second hard pole ear. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] 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 the indicated technical features. 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 invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0050] 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 one; 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.

[0051] In the present invention, 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.

[0052] 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 present invention. 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.

[0053] In the related art, lithium-ion batteries use low-temperature electrolytes to improve the charge and discharge capacity retention rate of lithium-ion batteries at low temperatures. However, lithium-ion batteries will still release lithium when charged at a high rate at low temperatures, which reduces the cycle life of lithium-ion batteries.

[0054] In order to solve the above problems, an embodiment of the present invention provides a winding core structure and a lithium-ion battery, in which the pole piece of the winding core structure acts as a heating resistor to heat the winding core structure, so that the temperature of the winding core structure increases, thereby avoiding the problem of lithium plating when the lithium-ion battery is charged at a low temperature and a high rate, thereby improving the cycle life of the lithium-ion battery.

[0055] The winding core structure and the lithium-ion battery provided by the embodiments of the present invention are described in detail below in conjunction with specific embodiments.

[0056] See also Figure 1 As shown, an embodiment of the present invention provides a core structure. The X-axis direction is the width direction of the core structure; the Y-axis direction is the thickness direction of the core structure; and the Z-axis direction is the height direction of the core structure (see Figure 5 and Figure 6 ). The X-axis, Y-axis, and Z-axis are perpendicular to each other.

[0057] The winding core structure includes a first pole piece 10 , a second pole piece 20 and a diaphragm 30 which are wound into shape.

[0058] After stacking the first pole piece 10, the diaphragm 30 and the second pole piece 20 in sequence, they are wound from the starting end to the ending end to form a roll core structure. 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, and the starting end of the roll core structure 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, and the ending end of the roll core structure is located on the outer side of the lithium-ion battery. The winding direction of the roll core structure is the extension direction from the starting end of the roll core structure toward the ending end.

[0059] The first pole piece 10 is located at the outermost side of the winding core structure. The first pole piece 10 can be a positive pole piece or a negative pole piece. It can be understood that when the first pole piece 10 is a positive pole piece, the second pole piece 20 is a negative pole piece, and when the first pole piece 10 is a negative pole piece, the second pole piece 20 is a positive pole piece. In this embodiment, the first pole piece 10 is a positive pole piece, and the second pole piece 20 is a negative pole piece.

[0060] The first electrode sheet 10 includes a first electrode current collector and a first active material layer coated on two opposite sides of the first electrode current collector. In some examples, aluminum foil or a composite current collector can be used as the first electrode current collector, and the composite current collector can include a polymer layer and two aluminum layers located on opposite sides of the polymer layer.

[0061] Figures 2 to 4 The first pole piece 10 in FIG. 1 is a schematic diagram of being unfolded after being wound. Figures 2 to 4As shown, the length direction of the first pole piece 10 is the X1 axis direction, the width direction of the first pole piece 10 is the Y1 axis direction, and the X1 axis and the Y1 axis are perpendicular to each other. The side of the first pole piece 10 in the -X1 axis direction is the left side of the first pole piece 10, and the side of the first pole piece 10 in the +X1 axis direction is the right side of the first pole piece 10.

[0062] The width direction of the first pole piece 10 is parallel to the height direction of the winding core structure.

[0063] See also Figure 2 As shown, the first pole piece 10 includes a double-sided region 10 a and a single-sided region 10 b connected to each other.

[0064] The first active material layer is disposed on both sides of the first current collector in the double-sided area 10a.

[0065] The first active material layer is disposed on one side of the first current collector in the single-sided area 10 b , and the first active material layer is not disposed on the other side of the first current collector in the single-sided area 10 b .

[0066] The first pole piece 10 also includes an empty foil area 10c connected to the single-sided area 10b. The portion of the first pole piece 10 where the first active material layer is not provided is the empty foil area 10c, that is, the empty foil area 10c only includes the first current collector.

[0067] A first soft electrode ear portion 11 and a second soft electrode ear portion 12 are disposed on the first current collector of the first electrode sheet 10 , and the first soft electrode ear portion 11 and the second soft electrode ear portion 12 are electrically connected to the first current collector, respectively.

[0068] The first soft electrode ear portion 11 and the second soft electrode ear portion 12 may be located on the same side of the first current collector in the height direction of the winding core structure, or may be located on both sides of the first current collector in the height direction of the winding core structure.

[0069] The first soft electrode ear portion 11 and the second soft electrode ear portion 12 may be electrically connected to a first power source, respectively.

[0070] See also Figure 5 and Figure 6 As shown, the first soft pole ear portion 11 is welded to the first hard pole ear 31. The first power source is electrically connected to the first soft pole ear portion 11 through the first hard pole ear 31.

[0071] See also Figure 5 and Figure 6 As shown, the second soft pole ear portion 12 is welded to the second hard pole ear 32. The first power source is electrically connected to the second soft pole ear portion 12 through the second hard pole ear 32.

[0072] In some examples, the minimum current of the first power source may be 5 A. This configuration ensures that the first power source can heat the lithium-ion battery.

[0073] In some examples, the maximum current of the first power supply may be 50 A. Such a configuration can prevent the first soft pole ear portion 11 and the second soft pole ear portion 12 from melting due to excessive current.

[0074] When the temperature of the winding core structure is lower than the preset temperature, the winding core structure is in a low temperature environment, that is, the lithium-ion battery is in a low temperature environment. In some examples, the preset temperature is 25°C.

[0075] The second pole piece 20 includes a second current collector and a second active material layer coated on the second current collector.

[0076] The second active material layer of the second pole piece 20 is provided with a pole lug groove, and the second pole lug 21 is provided in the pole lug groove. The second pole lug 21 is electrically connected to the second current collector of the second pole piece 20. It can be understood that the second pole lug 21 is provided on the second current collector of the second pole piece 20. When the first pole piece 10 is a positive pole piece and the second pole piece 20 is a negative pole piece, the first hard pole lug 31 and the second pole lug 21 can be used as charging and discharging pole lugs.

[0077] In some examples, the first hard electrode tab 31 and the second electrode tab 21 may be electrically connected to a second power source, respectively.

[0078] The second electrode tab 21 is located on one side of the second current collector in the height direction of the winding core structure.

[0079] When the core structure is in a low temperature environment, the first hard pole ear 31 of the core structure can be electrically connected to the positive electrode of the first power supply, and the second hard pole ear 32 can be electrically connected to the negative electrode of the first power supply. At this time, a first power supply circuit is formed, and the first pole piece 10 acts as a heating resistor to heat the core structure, so that the temperature of the core structure increases, thereby gradually increasing the internal temperature of the lithium-ion battery until it reaches the required preset temperature. It should be noted that in other embodiments, the first hard pole ear 31 can also be electrically connected to the negative electrode of the first power supply, and the second hard pole ear 32 can also be electrically connected to the positive electrode of the first power supply. The preset temperature can be 25°C.

[0080] When the lithium-ion battery is heated to a preset temperature, the second power supply is started to charge the lithium-ion battery. At this time, the positive electrode of the second power supply is connected to the first hard pole ear 31, and the negative electrode of the second power supply is connected to the second pole ear 21. At this time, a second power supply circuit is formed, and the lithium-ion battery is charged and discharged at a preset temperature.

[0081] It should be noted that when the lithium-ion battery is in a low temperature environment, the first power source is used to heat the lithium-ion battery. When the lithium-ion battery is heated to a preset temperature, the first power source and the second power source can work together to heat the lithium-ion battery while charging the lithium-ion battery.

[0082] The winding core structure provided in the embodiment of the present invention is electrically connected to the first power supply through the first soft pole ear portion 11 and the second soft pole ear portion 12 respectively when the winding core structure is in a low temperature environment. The first pole piece 10 can act as a heating resistor to heat the winding core structure, so that the temperature of the winding core structure increases, thereby avoiding the problem of lithium plating when the lithium-ion battery is charged at a low temperature and a large rate, thereby improving the cycle life of the lithium-ion battery.

[0083] In one possible implementation, see Figure 1 , Figure 5 and Figure 6 As shown, the projection of the first soft pole ear portion 11 in the thickness direction of the winding core structure does not overlap with the projection of the second soft pole ear portion 12. This arrangement can avoid the problem of short circuit between the first soft pole ear portion 11 and the second soft pole ear portion 12 when the first soft pole ear portion 11 is welded to the first hard pole ear 31 and the second soft pole ear portion 12 is welded to the second hard pole ear 32.

[0084] In the height direction of the winding core structure, the first soft pole ear portion 11 , the second soft pole ear portion 12 and the second pole ear 21 are located on the same side of the winding core structure.

[0085] The first soft pole ear portion 11 may be located in the double-sided area 10a, the single-sided area 10b, or the empty foil area 10c of the first pole piece 10. In other embodiments, a portion of the first soft pole ear portion 11 may be located in the double-sided area 10a and another portion in the single-sided area 10b.

[0086] The second soft pole ear portion 12 may be located in the double-sided area 10a, the single-sided area 10b, or the empty foil area 10c of the first pole piece 10. In other embodiments, a portion of the second soft pole ear portion 12 may be located in the double-sided area 10a and another portion in the single-sided area 10b.

[0087] For some examples, see Figure 2 As shown, the first soft pole ear portion 11 and the second soft pole ear portion 12 are both located in the double-sided region 10 a of the first pole piece 10 .

[0088] The position of the first soft electrode ear portion 11 on the double-sided region 10 a is not particularly limited.

[0089] The position of the second soft electrode ear portion 12 on the double-sided region 10 a is not particularly limited.

[0090] Further, see Figure 2As shown, from the left side to the right side of the first pole piece 10, the double-sided area 10a includes a first section 10a1, a second section 10a2 and a third section 10a3 connected in sequence. The third section 10a3 is connected to the single-sided area 10b. It should be noted that, from the left side to the right side of the first pole piece 10, the sizes of the first section 10a1, the second section 10a2 and the third section 10a3 are set as needed.

[0091] The first soft electrode ear portion 11 may be located in the first section 10a1, the second section 10a2, or the third section 10a3.

[0092] The second soft electrode ear portion 12 may be located in the first section 10a1, the second section 10a2, or the third section 10a3.

[0093] In the first example, see Figure 2 As shown, the first soft pole ear portion 11 is located in the first section 10a1, and the second soft pole ear portion 12 is located in the third section 10a3. It can be understood that there is no pole ear on the second section 10a2.

[0094] In the second example, see Figure 3 As shown, the first soft pole ear portion 11 is located in the first section 10a1, and the second soft pole ear portion 12 is located in the second section 10a2. It can be understood that there is no pole ear on the third section 10a3.

[0095] In the third example, see Figure 4 As shown, the first soft pole ear portion 11 is located in the second section 10a2, and the second soft pole ear portion 12 is located in the third section 10a3. It can be understood that there is no pole ear on the first section 10a1.

[0096] In one possible implementation, see Figure 1 and Figure 5 As shown, the first soft electrode ear portion 11 , the second soft electrode ear portion 12 and the second electrode ear 21 are arranged at intervals in the width direction of the winding core structure.

[0097] The order of the first soft electrode ear portion 11 , the second soft electrode ear portion 12 , and the second electrode ear 21 in the width direction of the winding core structure is not specifically limited.

[0098] Exemplarily, the order of the first soft pole ear portion 11, the second soft pole ear portion 12 and the second pole ear portion 21 in the width direction of the winding core structure can be the first soft pole ear portion 11, the second soft pole ear portion 12, the second pole ear portion 21, or the second soft pole ear portion 12, the first soft pole ear portion 11, the second pole ear portion 21, the first soft pole ear portion 11, the first soft pole ear portion 11, the second pole ear portion 21, the second soft pole ear portion 12, or the second pole ear portion 21, the first soft pole ear portion 11, the second soft pole ear portion 12.

[0099] In one possible implementation, see Figure 2 As shown, the first soft pole ear portion 11 includes a plurality of first soft pole ears 111, and the plurality of first soft pole ears 111 are welded to the first hard pole ear 31. The plurality of first soft pole ears 111 are arranged at intervals in the length direction of the first pole piece 10.

[0100] The material of the first soft electrode tab 111 may be the same as the material of the first current collector.

[0101] The number of the first soft electrode tabs 111 can be set according to actual needs. In some examples, the number of the first soft electrode tabs 111 can be 4 to 16.

[0102] The width of the first soft pole ear 111 in the width direction of the winding core structure can be 3 to 15 mm. In this way, it is possible to avoid the width of the first soft pole ear 111 being too small, which is not conducive to the alignment and overlap of multiple first soft pole ears 111 of the first soft pole ear portion 11, and increases the difficulty of manufacturing. It is also possible to avoid the width of the first soft pole ear 111 being too large, resulting in the first soft pole ear 111 occupying too much space, which is not conducive to the arrangement of the first soft pole ear portion 11 and the second soft pole ear portion 12, and the improvement of energy density.

[0103] In some examples, the width of the first soft electrode tab 111 in the width direction of the winding core structure is 5 to 10 mm.

[0104] The projection area of ​​the first soft pole ear 111 in the thickness direction of the winding core structure is the first area. In some examples, the overlapping area of ​​the projections of the multiple first soft pole ears 111 of the first soft pole ear portion 11 in the thickness direction of the winding core structure is greater than or equal to 3 / 5 of the first area. In this way, it can be ensured that there is sufficient contact area when the first soft pole ear portion 11 is welded with the first hard pole ear 31, avoiding the problem of desoldering and increased contact impedance caused by poor welding.

[0105] exist Figure 1 The dotted line L1 in FIG. 1 extends along the X-axis direction, that is, the dotted line L1 is parallel to the X-axis. The dotted line L1 is the central axis of the winding core structure, and the center of the winding core structure is located on the central axis.

[0106] In the thickness direction of the winding core structure, the multiple first soft pole ears 111 of the first soft pole ear portion 11 may be located on one side of the central axis. In other embodiments, in the thickness direction of the winding core structure, the multiple first soft pole ears 111 of the first soft pole ear portion 11 may also be located on both sides of the central axis. The number of first soft pole ears 111 on both sides of the central axis may be the same or different.

[0107] A plurality of bending lines are formed during the winding process of the first pole piece 10 . Figure 2The dotted line L2 in FIG. 1 is a bending line on the double-sided area 10a of the first pole piece 10. In the winding direction of the winding core structure, a plurality of bending lines separate the first pole piece 10 into a plurality of separation segments.

[0108] The first soft pole ears 111 of the first soft pole ear portion 11 can be arranged on adjacent partitions of the first pole sheet 10, that is, in the winding direction of the winding core structure, the partitions where the first soft pole ears 111 of the first soft pole ear portion 11 are located are arranged adjacently. Alternatively, the first soft pole ears 111 of the first soft pole ear portion 11 can also be arranged on non-adjacent partitions of the first pole sheet 10, that is, in the winding direction of the winding core structure, the partitions where the first soft pole ears 111 of the first soft pole ear portion 11 are located are not arranged adjacently.

[0109] See also Figure 2 As shown, the second soft pole ear portion 12 includes a plurality of second soft pole ears 121, and the plurality of second soft pole ears 121 are welded to the second hard pole ears 32. The plurality of second soft pole ears 121 are arranged at intervals in the length direction of the first pole piece 10.

[0110] The material of the second soft electrode tab 121 may be the same as the material of the first current collector.

[0111] The number of the second soft electrode tabs 121 can be set according to actual needs. The number of the second soft electrode tabs 121 can be the same as the number of the first soft electrode tabs 111 , or can be different from the number of the first soft electrode tabs 111 .

[0112] In some examples, the number of the second soft electrode tabs 121 may be 4 to 16. In this embodiment, the number of the second soft electrode tabs 121 is equal to the number of the first soft electrode tabs 111.

[0113] The width of the second soft pole ear 121 in the width direction of the winding core structure can be 3 to 15 mm. In this way, it is possible to avoid the width of the second soft pole ear 121 being too small, which is not conducive to the alignment and overlap of multiple second soft pole ears 121 of the second soft pole ear portion 12, increasing the difficulty of manufacturing. It is also possible to avoid the width of the second soft pole ear 121 being too large, resulting in the first soft pole ear 111 occupying too much space, which is not conducive to the arrangement of the first soft pole ear portion 11 and the second soft pole ear portion 12, and the improvement of energy density.

[0114] In some examples, the width of the first soft electrode tab 111 in the width direction of the winding core structure is equal to the width of the second soft electrode tab 121 in the width direction of the winding core structure. The width of the second soft electrode tab 121 in the width direction of the winding core structure is 5-10 mm.

[0115] The projection area of ​​the second soft electrode tab 121 in the thickness direction of the winding core structure is the second area. In some examples, the second area is equal to the first area.

[0116] The overlapping area of ​​the projections of the plurality of second soft pole ears 121 of the second soft pole ear portion 12 in the thickness direction of the winding core structure is greater than or equal to 3 / 5 of the second area. This arrangement can ensure that the second soft pole ear portion 12 and the second hard pole ear 32 have sufficient contact area when welded, avoiding the problem of desoldering and increased contact impedance caused by poor welding.

[0117] In the thickness direction of the winding core structure, the plurality of second soft pole ears 121 of the second soft pole ear portion 12 may be located on one side of the central axis, that is, the plurality of second soft pole ears 121 of the second soft pole ear portion 12 may be located Figure 1 In other embodiments, in the thickness direction of the winding core structure, the plurality of second soft pole ears 121 of the second soft pole ear portion 12 may also be located on both sides of the central axis. The number of second soft pole ears 121 on both sides of the central axis may be the same or different.

[0118] Exemplarily, in the thickness direction of the winding core structure, the plurality of first soft electrode tabs 111 of the first soft electrode tab portion 11 and the plurality of second soft electrode tabs 121 of the second soft electrode tab portion 12 are located on the same side of the dotted line L1 .

[0119] The second soft pole ears 121 of the second soft pole ear portion 12 can be arranged on adjacent partitions of the first pole piece 10, that is, in the winding direction of the winding core structure, the partitions where the second soft pole ears 121 of the second soft pole ear portion 12 are located are arranged adjacently. Alternatively, the second soft pole ears 121 of the second soft pole ear portion 12 can also be arranged on non-adjacent partitions of the first pole piece 10, that is, in the winding direction of the winding core structure, the partitions where the second soft pole ears 121 of the second soft pole ear portion 12 are located are not arranged adjacently.

[0120] In some examples, each first soft pole ear 111 of the first soft pole ear portion 11 and each second soft pole ear 121 of the second soft pole ear portion 12 are on adjacent partition segments, that is, each first soft pole ear 111 of the first soft pole ear portion 11 is on adjacent partition segments, and each second soft pole ear 121 of the second soft pole ear portion 12 is on adjacent partition segments.

[0121] In other examples, each first soft pole ear 111 of the first soft pole ear portion 11 and each second soft pole ear 121 of the second soft pole ear portion 12 are on non-adjacent partition segments, that is, each first soft pole ear 111 of the first soft pole ear portion 11 is on a non-adjacent partition segment, and each second soft pole ear 121 of the second soft pole ear portion 12 is on a non-adjacent partition segment.

[0122] It should be noted that, for the first pole piece 10, in the length direction of the first pole piece 10, among the multiple first soft pole ears 111 of the first soft pole ear portion 11 and the multiple second soft pole ears 121 of the second soft pole ear portion 12, the larger the distance between the closest first soft pole ear 111 and the second soft pole ear 121, the faster the core structure heats up when heated.

[0123] Further, see Figure 5 As shown, the width of the first hard pole tab 31 in the width direction of the winding core structure is equal to the width of the second hard pole tab 32 in the width direction of the winding core structure.

[0124] The width of the first hard pole ear 31 in the width direction of the winding core structure can be 5 to 20 mm. This arrangement allows the first hard pole ear 31 to have sufficient welding contact area with the first soft pole ears 111 of the first soft pole ear portion 11, thereby avoiding the problem of increased ohmic impedance due to poor contact.

[0125] In some examples, the width of the first hard pole tab 31 is 6 to 12 mm, and the thickness of the first hard pole tab 31 in the thickness direction of the winding core structure is 0.6 to 1.5 mm.

[0126] The width of the second hard pole tab 32 in the width direction of the winding core structure can be 5 to 20 mm. This arrangement allows the second hard pole tab 32 to have sufficient welding contact area with the plurality of second soft pole tabs 121 of the second soft pole tab portion 12, thereby avoiding the problem of increased ohmic impedance due to poor contact.

[0127] In some examples, the width of the second hard pole tab 32 is 6 to 12 mm, and the thickness of the second hard pole tab 32 in the thickness direction of the winding core structure is 0.6 to 1.5 mm.

[0128] In a possible implementation, for the winding core structure, in the width direction of the winding core structure, the first soft pole ear 111 closest to the second soft pole ear 12 and the second soft pole ear 121 closest to the first soft pole ear 11 can be spaced at a minimum distance of 2 to 10 mm. This arrangement avoids the first soft pole ear 111 and the second soft pole ear 12 being welded together due to the close distance between the first soft pole ear 111 and the second soft pole ear 121, and thus failing to function as two pole ears.

[0129] For example, in the width direction of the winding core structure, the first soft pole ear 111 closest to the second soft pole ear portion 12 and the second soft pole ear 121 closest to the first soft pole ear portion 11 may be spaced at a minimum distance of 2 mm.

[0130] Therein, in the width direction of the winding core structure, the maximum distance between the first soft pole ear 111 closest to the second soft pole ear portion 12 and the second soft pole ear 121 closest to the first soft pole ear portion 11 is not specifically limited as long as it does not exceed the width of the winding core structure.

[0131] An embodiment of the present invention provides a lithium-ion battery, including a roll core structure.

[0132] 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.

[0133] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A winding core structure, characterized in that: It comprises a first pole piece (10) formed by winding, a diaphragm (30) and a second pole piece (20); The current collector of the first pole piece (10) is provided with a first soft pole ear portion (11) and a second soft pole ear portion (12) which are arranged at intervals; A projection of the first soft pole ear portion (11) in the thickness direction of the winding core structure does not overlap with a projection of the second soft pole ear portion (12).

2. The winding core structure according to claim 1, characterized in that: A pole lug groove is provided on the active material layer of the second pole piece (20), a second pole lug (21) is provided in the pole lug groove, and the second pole lug (21) is electrically connected to the current collector of the second pole piece (20); The first soft pole ear portion (11), the second soft pole ear portion (12) and the second pole ear (21) are arranged at intervals in the width direction of the winding core structure.

3. The winding core structure according to claim 2, characterized in that: In the height direction of the winding core structure, the first soft pole ear portion (11), the second soft pole ear portion (12) and the second pole ear (21) are located on the same side of the winding core structure.

4. The winding core structure according to claim 3, characterized in that: The first soft pole ear portion (11) comprises a plurality of first soft pole ears (111), the projection area of ​​the first soft pole ears (111) in the thickness direction of the winding core structure is a first area, and the overlapping area of ​​the projections of the plurality of first soft pole ears (111) in the thickness direction of the winding core structure is greater than or equal to 3 / 5 of the first area; The second soft pole ear portion (12) comprises a plurality of second soft pole ears (121), the projection area of ​​the second soft pole ears (121) in the thickness direction of the winding core structure is a second area, and the overlapping area of ​​the projections of the plurality of second soft pole ears (121) in the thickness direction of the winding core structure is greater than or equal to 3 / 5 of the second area.

5. The winding core structure according to claim 4, characterized in that: In the width direction of the winding core structure, the minimum interval between the first soft pole ear (111) closest to the second soft pole ear portion (12) and the second soft pole ear (121) closest to the first soft pole ear portion (11) is 2 to 10 mm.

6. The winding core structure according to claim 4, characterized in that: The width of the first soft electrode tab (111) in the width direction of the winding core structure is equal to the width of the second soft electrode tab (121) in the width direction of the winding core structure.

7. The winding core structure according to claim 4, characterized in that: The number of the first soft pole ears (111) is the same as the number of the second soft pole ears (121); or the number of the first soft pole ears (111) is different from the number of the second soft pole ears (121).

8. The winding core structure according to claim 4, characterized in that: The winding core structure has a central axis, and in the thickness direction of the winding core structure, the multiple first soft pole ears (111) of the first soft pole ear portion (11) are located on one side of the central axis; or, in the thickness direction of the winding core structure, the multiple first soft pole ears (111) of the first soft pole ear portion (11) are respectively located on both sides of the central axis.

9. The winding core structure according to claim 4, characterized in that: The winding core structure has a central axis, and in the thickness direction of the winding core structure, each second soft pole ear (121) of the second soft pole ear portion (12) is located on one side of the central axis; or, in the thickness direction of the winding core structure, each second soft pole ear (121) of the second soft pole ear portion (12) is located on both sides of the central axis.

10. The winding core structure according to claim 4, characterized in that: A plurality of bending lines are formed during the winding process of the first pole piece (10), and in the winding direction of the winding core structure, the plurality of bending lines separate the first pole piece (10) into a plurality of separation segments; Each first soft pole ear (111) of the first soft pole ear portion (11) and each second soft pole ear (121) of the second soft pole ear portion (12) are both on adjacent partition segments; or, each first soft pole ear (111) of the first soft pole ear portion (11) and each second soft pole ear (121) of the second soft pole ear portion (12) are both on non-adjacent partition segments.

11. The winding core structure according to any one of claims 1 to 10, characterized in that: The first pole piece (10) comprises a first section (10a1), a second section (10a2) and a third section (10a3) connected in sequence, the first soft pole ear (11) is located in the first section (10a1), and the second soft pole ear (12) is located in the third section (10a3).

12. The winding core structure according to any one of claims 4 to 10, characterized in that: The plurality of first soft pole ears (111) of the first soft pole ear portion (11) are welded to the first hard pole ear (31), and the plurality of second soft pole ears (121) of the second soft pole ear portion (12) are welded to the second hard pole ear (32).

13. The winding core structure according to any one of claims 1 to 10, characterized in that: The first pole piece (10) comprises a single-sided area (10b) and a double-sided area (10a) connected to each other, a first active material layer is arranged on one side of the current collector of the single-sided area (10b), and the first active material layer is arranged on both sides of the current collector of the double-sided area (10a); The first soft pole ear portion (11) is located in the double-sided area (10a) and / or the single-sided area (10b), and the second soft pole ear portion (12) is located in the double-sided area (10a) and / or the single-sided area (10b).

14. A lithium ion battery, characterized in that: It comprises the winding core structure as described in any one of claims 1 to 13.

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