Roll core structure and battery
By designing flat and arc-shaped current collectors in the core structure without coating them with active material and using insulating adhesive paper, the problem of cell deformation caused by uneven core thickness is solved, the bonding consistency between the electrode and the separator is improved, and the battery life is extended.
Patent Information
- Application Number
- CN202423121165.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-17
- Publication Date
- 2025-12-19
- Estimated Expiration
- 2034-12-17
AI Technical Summary
The uneven thickness of existing wound battery cells leads to uneven pressure during the high-temperature clamping process, affecting the bonding consistency between the electrode and the separator, and making them prone to deformation during charging and discharging.
The core structure is formed by winding a positive current collector, a diaphragm, and a negative current collector. It includes a flat area and an arc area. The current collectors on both sides of the arc area are not coated with active material, and the uncoated areas are covered with insulating tape to increase the thickness uniformity of the core and the bonding consistency between the electrode and the diaphragm.
It improves the uniformity of cell thickness, reduces deformation during charging and discharging, and extends battery life.
Smart Images
Figure CN223693179U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of lithium-ion battery technology, and in particular to a core structure and battery. Background Technology
[0002] For some wound-structured battery cells, the tab connection position is generally located on the current collector in the straight section of the wound structure. One end of the tab needs to extend into the battery cell and connect to the pre-set tab connection position on the current collector; such as Figure 1 As shown, the total longitudinal thickness at position II is the thinnest. Compared with position I, position II is thinner by the thickness of a positive electrode tab and the thickness of a layer of negative electrode active material at point ①. Compared with position III, position II is thinner by the thickness of a negative electrode tab and the thickness of a layer of positive electrode active material at point ②. Therefore, the core thickness of existing wound-type battery cells is uneven, and the thickness difference at some local locations is too large.
[0003] In the high-temperature pressure formation process of battery cells, the uneven thickness of the existing wound-type battery cells leads to uneven pressure on the flat areas of the cell (positions I and III have greater thickness and therefore experience greater pressure), thus affecting the bonding consistency between the positive and negative electrodes and the separator. Furthermore, during charging and discharging, the cell electrodes undergo expansion and contraction, which can easily cause deformation in cells with poor bonding between the positive and negative electrodes and the separator.
[0004] The above information is provided as background information only to aid in understanding this disclosure and does not constitute an assertion or admission that any of the above content can be used as prior art relative to this disclosure. Utility Model Content
[0005] The purpose of this invention is to provide a core structure and battery to solve or at least partially solve the technical problems existing in the prior art.
[0006] To achieve this objective, the present invention adopts the following technical solution:
[0007] In a first aspect, the present invention provides a wound core structure, which is formed by winding a positive current collector, a diaphragm and a negative current collector stacked in sequence, including a straight region and two arc regions, wherein the two arc regions are respectively located on both sides of the straight region along a first direction;
[0008] The positive current collector includes a first straight section located in the straight region for connecting the positive electrode tab; the negative current collector includes a second straight section located in the straight region for connecting the negative electrode tab; the first straight section is not coated with positive active material, and the second straight section is not coated with negative active material.
[0009] Optionally, the positive current collector further comprises two first arc-shaped segments respectively connected to two ends of the first flat segment, and the two first arc-shaped segments are respectively located in the two circular arc regions;
[0010] The negative current collector further comprises two second arc-shaped segments respectively connected to two ends of the second flat segment, and the two second arc-shaped segments are respectively located in the two circular arc regions.
[0011] The first arc-shaped segment is not coated with positive active material, or at least a part of the first arc-shaped segment adjacent to the first flat segment is not coated with positive active material; and the second arc-shaped segment is not coated with negative active material, or at least a part of the second arc-shaped segment adjacent to the second flat segment is not coated with negative active material.
[0012] Optionally, the central angle of the region on the first arc-shaped segment which is not coated with positive active material is greater than 0° and less than or equal to 180°; and the central angle of the region on the second arc-shaped segment which is not coated with negative active material is greater than 0° and less than or equal to 180°.
[0013] Optionally, the first flat segment, the second flat segment, the region on the first arc-shaped segment which is not coated with positive active material, and the region on the second arc-shaped segment which is not coated with negative active material are all attached with insulating adhesive tape.
[0014] Optionally, the winding core structure further comprises a fixing tape; one end of the fixing tape is bonded to the winding end of the positive current collector, and the other end of the fixing tape is bonded to the surface of the winding core structure.
[0015] Optionally, the total length of the winding of the positive current collector is greater than the total length of the winding of the negative current collector, but the area of the negative current collector covered by the negative active material is greater than the area of the negative current collector covered by the positive active material.
[0016] Optionally, the positive current collector further comprises a third flat segment adjacent to the first flat segment in the flat region; and the third flat segment is located on the side of the first flat segment away from the second flat segment.
[0017] The negative current collector further comprises a fourth flat segment adjacent to the second flat segment in the flat region; and the fourth flat segment is located on the side of the second flat segment away from the first flat segment.
[0018] The third flat segment and the fourth flat segment are also respectively attached with insulating adhesive tape on the side close to each other.
[0019] Optionally, the separator is an insulating separator.
[0020] The utility model provides a battery, including roll core, positive pole lug and negative pole lug, its characterized in be, the roll core adopts a roll core structure as above.
[0021] Optionally, the battery is a lithium ion battery.
[0022] Compared with the prior art, the utility model has the following beneficial effects:
[0023] The roll core structure provided by the utility model solves the problem of cell deformation in the charging and discharging process caused by uneven cell thickness, further solves the problem of excessive thickness expansion caused by cell deformation, and effectively increases the service life of the battery in charging and discharging.
[0024] The utility model has other characteristics and advantages, which will be apparent or will be described in detail in the accompanying drawings and subsequent specific embodiments incorporated herein, which are used together to explain the specific principles of the utility model. BRIEF DESCRIPTION OF DRAWINGS
[0025] In order to more clearly illustrate the technical scheme in the embodiments of the utility model or the prior art, the accompanying drawings needed to be used in the embodiment or the prior art description will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the utility model, and those skilled in the art can also obtain other accompanying drawings according to these accompanying drawings without creating any creative labor.
[0026] Figure 1 It is the structural principle diagram of the roll core of the prior art.
[0027] Figure 2 It is the structural principle diagram of the roll core provided by the embodiment of the utility model.
[0028] Figure 3 It is the partial structure enlarged view in Figure 2
[0029] In the drawing: 10, positive current collector; 100, first straight section; 101, positive pole lug; 102, first circular arc section; 20, negative current collector; 200, second straight section; 201, negative pole lug; 202, second circular arc section; 21, negative active material; 30, diaphragm; 40, insulating adhesive tape; 50, straight area; 60 circular arc area; 70, fixing adhesive tape. DETAILED DESCRIPTION
[0030] To explain possible application scenarios, technical principles, specific implementation schemes, and the purposes and effects of the present application in detail, the following embodiments are described in conjunction with the accompanying drawings. The embodiments described herein are only used to more clearly illustrate the technical solutions of the present application, and therefore only serve as examples, and cannot limit the protection scope of the present application.
[0031] In this paper, the term "embodiment" means that the specific features, structures or characteristics described in conjunction with the embodiment can be included in at least one embodiment of the present application. The term "embodiment" appearing at various places in the specification does not necessarily refer to the same embodiment, and does not particularly limit its independence or association with other embodiments. In principle, in the present application, as long as there is no technical contradiction or conflict, each technical feature mentioned in each embodiment can be combined in any way to form a corresponding implementable technical solution.
[0032] Unless otherwise defined, the meaning of the technical terms used herein is the same as that generally understood by those skilled in the art to which the present application belongs; the use of related terms herein is only for the purpose of describing specific embodiments, and is not intended to limit the present application.
[0033] In the description of the present application, the phrase "and / or" is a description of the logical relationship between the objects, which means that there can be three relationships, for example, A and / or B, which means that there are three cases: A exists, B exists, and A and B exist at the same time. In addition, the character " / " in this paper generally represents that the associated objects before and after are a "or" logical relationship.
[0034] In the present application, terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual quantity, primary and secondary or order relationship between the entities or operations.
[0035] Without more limitations, in the present application, the phrases "include", "contain", "have" or other similar expressions used in the sentence are intended to cover non-exclusive inclusion, and these expressions do not exclude the presence of other elements in the process, method or product including the described elements, so that the process, method or product including a series of elements can not only include those limited elements, but also include other elements not explicitly listed, or also include elements inherent to such process, method or product.
[0036] As the same understanding in the "Examination Guidelines", in the present application, "greater than", "less than", "exceed" and the like are understood as not including the number; "above", "below", "within" and the like are understood as including the number. In addition, in the description of the embodiments of the present application, the meaning of "multiple" is more than two (including two), and similar expressions related to "multiple" are also understood in this way, for example, "multiple groups", "multiple times" and the like, unless otherwise explicitly specified.
[0037] In the description of the embodiments of the present application, the spatially related expressions used, such as "center", "longitudinal", "transverse", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "vertical", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like, indicate the orientation or positional relationship based on the orientation or positional relationship shown in the specific embodiment or the drawing, and are only for the convenience of describing the specific embodiments of the present application or for the reader to understand, and do not indicate or imply that the indicated device or component must have a specific position, a specific orientation, or be constructed or operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.
[0038] Unless otherwise explicitly specified or limited, in the description of the embodiments of the present application, the terms "mount", "connect", "connect", "fix", "set" and the like should be broadly understood. For example, the "connection" can be fixed connection, or detachable connection, or integral setting; it can be mechanical connection, or electrical connection, or communication connection; it can be directly connected, or indirectly connected through an intermediate medium; it can be the communication or interaction relationship between two elements. For those skilled in the art to which the present application belongs, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.
[0039] Embodiment one:
[0040] Please refer to Figure 2 and Figure 3 , Figure 2 is a structural principle diagram of a winding core provided by the embodiment of the present application, Figure 3 is Figure 2 an enlarged view of part of the structure in
[0041] As shown in Figure 2 and Figure 3 , the winding core structure is formed by sequentially stacking the positive current collector 10, the separator 30 and the negative current collector 20 through winding;
[0042] The winding core structure includes a flat area 50 and two circular arc areas 60, and the two circular arc areas 60 are located on both sides of the flat area 50 along a first direction; in the present embodiment, the first direction refers toFigure 2 Horizontal;
[0043] Specifically, the positive current collector 10 includes a first straight section 100 located in the straight region 50 for connecting the positive electrode tab 101; the negative current collector 20 includes a second straight section 200 located in the straight region 50 for connecting the negative electrode tab 201.
[0044] The first straight section 100 is not coated with positive electrode active material 11, and the second straight section 200 is not coated with negative electrode active material 21.
[0045] The improved core structure, compared to positions I and III, has only one less positive tab 101 or negative tab 201 in position II, which reduces the core thickness difference in the flat area 50, improves the thickness flatness of the battery cell, and consequently improves the pressure uniformity in the flat area of the battery cell, and the bonding consistency between the positive and negative electrodes and the separator is also improved accordingly.
[0046] Furthermore, the positive current collector 10 also includes two first arc-shaped segments 102 respectively connected to the two ends of the first straight segment 100, and the two first arc-shaped segments 102 are respectively located in two circular arc regions 60;
[0047] The negative electrode current collector 20 also includes two second arc-shaped segments 202 connected to the two ends of the second straight segment 200, and the two second arc-shaped segments 202 are located in two circular arc regions 60 respectively;
[0048] Among them, the first arc segment 102 is Figure 2 The current collector at position ③ in the middle, the second arc segment 202 is... Figure 2 The current collector section at position ④ in the middle;
[0049] In this embodiment, the positive electrode active material 11 is not coated on the first arc segment 102, or at least a portion of the first arc segment 102 adjacent to the first straight segment 100 is not coated with the positive electrode active material 11; the negative electrode active material 21 is not coated on the second arc segment 202, or at least a portion of the second arc segment 202 adjacent to the second straight segment 200 is not coated with the negative electrode active material 21.
[0050] Specifically, the areas on the first arc segment 102 where the positive electrode active material 11 is not coated and the areas on the second arc segment 202 where the negative electrode active material 21 is not coated are both arc-shaped.
[0051] In this embodiment, the central angle of the area on the first arc segment 102 where the positive electrode active material 11 is not coated is greater than 0° and less than or equal to 180°; the central angle of the area on the second arc segment 202 where the negative electrode active material 21 is not coated is greater than 0° and less than or equal to 180°.
[0052] For example, such asFigure 2 As shown, a represents the angle of the central angle of the above-mentioned arc; when a is 180 degrees, it represents that no active material is coated on the first arc segment 102 or the second arc segment 202; when a is 0 degrees, it represents that all the first arc segment 102 or the second arc segment 202 is coated with active material; therefore, in this embodiment, in order to avoid the flow of active material into the flat area 50, a part of the buffer area is reserved on the current collector of the arc area 60.
[0053] Further, the first flat segment 100, the second flat segment 200, the region of the first arc segment 102 on which no positive active material 11 is coated, and the region of the second arc segment 202 on which no negative active material 21 is coated are all pasted with insulating adhesive tape 40.
[0054] Because the current equipment or process cannot achieve a completely smooth current collector, there are more or less some "burrs" on the current collector, in order to avoid the phenomenon that the burrs pierce the diaphragm 30 and cause liquid leakage, the insulating adhesive tape 40 is pasted in the region where no active material is coated in this embodiment.
[0055] Further, the positive current collector 10 further comprises a third flat segment located in the flat area 50 and adjacent to the first flat segment 100; the third flat segment is located on the side of the first flat segment 100 away from the second flat segment 200;
[0056] The negative current collector 20 further comprises a fourth flat segment located in the flat area 50 and adjacent to the second flat segment 200; the fourth flat segment is located on the side of the second flat segment 200 away from the first flat segment 100;
[0057] As shown, the side of the third flat segment and the fourth flat segment close to each other (i.e. the lower side of the third flat segment and the upper side of the fourth flat segment) is also respectively bonded with insulating adhesive tape 40. Figure 2
[0058] In this embodiment, the winding end of the positive current collector 10 is bonded on the surface of the core structure by the fixing adhesive tape 70, specifically, one end of the fixing adhesive tape 70 is bonded at the winding end of the positive current collector 10, and the other end of the fixing adhesive tape 70 is bonded on the surface of the core structure.
[0059] It should be noted that in this embodiment, the total length of the winding of the positive current collector 10 is greater than the total length of the winding of the negative current collector 20; however, according to the process requirement, the coating area of the negative active material 21 needs to be larger, therefore, in this embodiment, the area of the negative current collector 20 covered by the negative active material 21 is larger than the area of the negative current collector 20 covered by the positive active material 11.
[0060] In this embodiment, the diaphragm 30 is an insulating diaphragm.
[0061] In conclusion, the improved winding core structure provided in the embodiment solves the problem of deformation of the battery cell in the charging and discharging process caused by uneven thickness of the battery cell, and further solves the problem of excessive thickness expansion of the battery cell caused by deformation of the battery cell.
[0062] Embodiment Two
[0063] The embodiment provides a battery, which comprises a winding core, a positive electrode tab 101 and a negative electrode tab 201, and the winding core adopts the winding core structure as described in Embodiment One.
[0064] Based on the detailed description of the winding core structure in Embodiment One, the description will not be repeated in this embodiment.
[0065] Specifically, the battery is a lithium ion battery.
[0066] The battery provided in the embodiment adopts the improved winding core structure, and compared with the existing winding type structure battery cell, the thickness of the battery cell is more uniform, and the problem of deformation of the battery cell in the charging and discharging process is less likely to occur, thereby effectively increasing the service life of the battery in the charging and discharging process.
[0067] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than limit the present application; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced by equivalent features; and these modifications or replacements do not make the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.
Claims
1. A core structure formed by winding a positive current collector (10), a separator (30) and a negative current collector (20) in sequence, comprising a flat section (50) and two circular arc sections (60), the two circular arc sections (60) being located on both sides of the flat section (50) along a first direction. The positive current collector (10) comprises a first flat section (100) for connecting the positive tab (101) at the flat area (50); the negative current collector (20) comprises a second flat section (200) for connecting the negative tab (201) at the flat area (50); characterized in that, No positive active material (11) is coated on the first flat section (100), and no negative active material (21) is coated on the second flat section (200).
2. A core structure according to claim 1, wherein The positive current collector (10) further comprises two first arc sections (102) connected to both ends of the first flat section (100), respectively, and the two first arc sections (102) are located in the two circular arc sections (60), respectively. The negative current collector (20) further comprises two second arc sections (202) connected to both ends of the second flat section (200), respectively, and the two second arc sections (202) are located in the two circular arc sections (60), respectively. No positive active material (11) is coated on the first arc section (102), or at least no positive active material (11) is coated on a part of the first arc section (102) adjacent to the first flat section (100) ; and no negative active material (21) is coated on the second arc section (202), or at least no negative active material (21) is coated on a part of the second arc section (202) adjacent to the second flat section (200).
3. A core structure according to claim 2, wherein The central angle of the region on the first arc section (102) on which no positive active material (11) is coated is greater than 0° and less than or equal to 180°; and the central angle of the region on the second arc section (202) on which no negative active material (21) is coated is greater than 0° and less than or equal to 180°.
4. A core structure according to claim 3, wherein The first flat section (100), the second flat section (200), the region on the first arc section (102) on which no positive active material (11) is coated, and the region on the second arc section (202) on which no negative active material (21) is coated are all provided with an insulating adhesive tape (40).
5. A core structure according to claim 2, wherein A fixing tape (70) is further included, one end of the fixing tape (70) being adhered to the winding end of the positive current collector (10), and the other end of the fixing tape (70) being adhered to the surface of the core structure.
6. A core structure according to claim 2, wherein The total length of the winding of the positive current collector (10) is greater than the total length of the winding of the negative current collector (20), but the area of the negative current collector (20) covered by the negative active material (21) is greater than the area of the negative current collector (20) covered by the positive active material (11).
7. A core structure according to claim 4, wherein The positive current collector (10) further comprises a third flat section adjacent to the first flat section (100) in the flat section (50), and the third flat section is located on the side of the first flat section (100) away from the second flat section (200). The negative current collector (20) further comprises a fourth flat section located at the flat section (50) and adjacent to the second flat section (200); the fourth flat section is located at a side of the second flat section (200) away from the first flat section (100). The side of the third flat section and the fourth flat section close to each other is also bonded with an insulating adhesive tape (40) respectively.
8. A core structure according to claim 1, wherein The diaphragm (30) is an insulating diaphragm.
9. A battery comprising a jelly-roll, a positive electrode tab (101) and a negative electrode tab (201), characterized by, The winding core adopts the winding core structure as claimed in any one of claims 1-8.
10. The battery of claim 9, wherein The battery is a lithium ion battery.