Lithium ion battery roll core and battery
By setting expansion pads and flattening tape at the corners inside the lithium-ion battery core and setting protective tape at the outer edge, the structural imbalance caused by the gap between the inner rings of the core is solved, thus improving the stability and safety of the battery.
Patent Information
- Application Number
- CN202423201444.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-25
- Publication Date
- 2026-01-09
- Estimated Expiration
- 2034-12-25
AI Technical Summary
In lithium-ion battery cores, if the positive and negative electrode sheets cannot be fully inserted to the bottom, gaps will exist at the inner corners. Over time, the electrode sheets will expand and thicken, resulting in uneven stress in the internal structure of the core, which will affect lithium-ion migration and may cause battery surface warping and safety risks.
An expansion padding tape is placed at the corner position inside the core. The high-temperature formation process is used to expand it and fill the corner gap. A finishing protective tape is placed on the outside to prevent electrode displacement and optimize the core structure.
By filling the corner gaps with expansion pads and flat tape, the internal structure of the core is balanced, reducing arching and deformation on the battery surface, and improving the stability and safety of battery use.
Smart Images
Figure CN223785156U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to lithium ion battery technical field, concretely relates to a lithium ion battery roll core and battery. BACKGROUND
[0002] The roll core of winding structure in lithium ion battery, many roll core structures have the problem that the innermost circle positive and negative pole piece cannot be inserted to the bottom, the pole piece cannot be inserted to the bottom can make the roll core inner circle corner gap, in the long-term use after the battery leaves factory, the pole piece charge and discharge thickening, the roll core internal first fold corner gap can be even bigger, causes the stress of roll core internal structure to be unbalanced, influences lithium ion migration between pole piece, causes the battery pole piece lithium precipitation, thereby causes the battery surface easy to appear warping, arching etc. UTILITY MODEL CONTENTS
[0003] The utility model provides a lithium ion battery roll core and battery to solve the above problems, and the technical scheme provided by the utility model is:
[0004] A lithium ion battery roll core, including positive pole piece, negative pole piece and diaphragm, the positive pole piece, negative pole piece and diaphragm are wound into roll core structure;
[0005] In the roll core structure, the pole piece on the roll core internal corner position is provided with expansion pad flat adhesive tape, the expansion pad flat adhesive tape can be expanded to form the filler in the roll core structure internal corner after roll core formation;
[0006] The pole piece of the roll core internal corner position provided with expansion pad flat adhesive tape is positive pole piece or negative pole piece, and the expansion pad flat adhesive tape is arranged on the pole piece powder layer on the inside of the roll core internal corner position.
[0007] To optimize the above technical scheme, the specific measures taken further include:
[0008] Further, the expansion pad flat adhesive tape and the expansion pad flat adhesive tape are staggered between the roll core internal pole piece head end.
[0009] The filler formed by the expansion pad flat adhesive tape after the roll core formation is tightly attached to the roll core internal pole piece head end provided with the expansion pad flat adhesive tape.
[0010] Further, the distance between the pole piece corner point of the inside surface of the roll core internal corner and the roll core internal pole piece head end on the inside is 2-5mm, and the width of the expansion pad flat adhesive tape is less than the distance.
[0011] The roll core internal corner is the internal corner of the first fold or the second fold of the roll core, and the inside of the roll core internal corner has the roll core internal pole piece head end.
[0012] Further, the outer side of the roll core structure is provided with a tail protection tape, and the tail protection tape is located at the tail end of the roll core pole piece.
[0013] The tail protection tape forms a smooth connection between the tail end of the roll core pole piece and the outer side of the pole piece of the roll core.
[0014] Further, at the tail end of the roll core pole piece, if there is no other tail end of the roll core pole piece on the inner side, the tail protection tape connects the outer side of the end of the tail end of the roll core pole piece and the pole piece on the front side of the tail end of the roll core pole piece; at the tail end of the roll core pole piece, if there is other tail end of the roll core pole piece on the inner side, the tail protection tape connects the outer side of the end of the tail end of the roll core pole piece and the pole piece on the front side of the other tail end of the roll core pole piece on the inner side.
[0015] The expansion pad flat tape is a thermal expansion tape.
[0016] The tail protection tape is a common tape.
[0017] The utility model discloses still protect a kind of lithium ion battery, containing the lithium ion battery roll core of above.
[0018] Compared with prior art, the utility model has the beneficial effects that:
[0019] The utility model is applied to the roll core with gap in inner circle corner, and the positive plate or negative plate of the roll core inner circle cannot be flush with the edge of the innermost side of the inner circle, and there is a certain gap; the utility model is attached to the position close to the corner of the positive plate or negative plate during winding of the roll core, and the tape promotes swelling expansion under high-temperature condition of battery formation process, to fill the gap of the roll core corner, balance and support the internal structure of the battery, effectively eliminate the defect that the internal stress of the roll core is unbalanced due to corner gap, make the internal structure of the battery more stable, and reduce the arching and deformation of the battery surface in the subsequent charging and discharging process.
[0020] The utility model discloses still roll core structure's outer side is provided with tail protection tape, and tail protection tape is located at the tail end of roll core pole piece, and it is prevented that pole piece displacement is attached to tail protection tape in the outermost circle of roll core. ACCURACY
[0021] Figure 1 It is the A structure roll core structure schematic diagram before pressurization formation;
[0022] Figure 2 It is the A structure roll core structure schematic diagram after pressurization formation;
[0023] Figure 3 It is the B structure roll core structure schematic diagram before pressurization formation;
[0024] Figure 4A structure schematic diagram of the B structure roll core after pressure formation;
[0025] In the figure: 1-positive electrode sheet, 2-negative electrode sheet, 3-first corner expansion pad flat tape, 4-second corner expansion pad flat tape, 5-first corner expansion pad flat tape after expansion, 6-second corner expansion pad flat tape after expansion, 7-third corner expansion pad flat tape, 8-third corner expansion pad flat tape after expansion, 9-first end protection tape, 10-second end protection tape, 11-third end protection tape. DETAILED DESCRIPTION
[0026] The above content of the utility model will be further described in the form of examples, but this should not be understood as the scope of the above subject matter of the utility model is limited to the following examples, and any technology realized based on the above content of the utility model belongs to the scope of the utility model.
[0027] In the description of the utility model, it also needs to be explained that:
[0028] The orientation or positional relationship therein is based on the relationship shown in the drawings, which is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the indicated device or component must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the utility model.
[0029] The utility model provides a kind of lithium ion battery roll core, including positive electrode sheet 1, negative electrode sheet 2 and diaphragm, positive electrode sheet 1, negative electrode sheet 2 and diaphragm are wound into roll core structure;
[0030] In the roll core structure, expansion pad flat tape is arranged on the electrode sheet at the corner position inside the roll core, and the expansion pad flat tape can be expanded to form a filler after the roll core formation to fill the corner inside the roll core structure;
[0031] The electrode sheet with expansion pad flat tape at the corner position inside the roll core is positive electrode sheet or negative electrode sheet, and the expansion pad flat tape is arranged on the electrode sheet powder layer on the inside of the corner position inside the roll core.
[0032] The scheme of the application is applied to the roll core with gap at the corner of inner ring, and the positive electrode sheet 1 or negative electrode sheet 2 of the roll core inner ring cannot be flush with the edge of the innermost side of the inner ring, and there will be a certain gap;The application is attached to the position close to the corner of positive electrode sheet 1 or negative electrode sheet 2 when winding the roll core, and the adhesive tape promotes swelling and expansion under high temperature conditions in the battery formation process, thereby filling the gap of the corner of the roll core, and playing the role of balancing and supporting the internal structure of the battery.
[0033] In the applied roll core structure, each positive and negative electrode stack is considered as a layer, and the number of winding layers is less than or equal to 35 and greater than or equal to 2.
[0034] In some embodiments, the expansion pad flat tape is arranged alternately with the head end of the inner pole piece of the jelly-roll at the position where the expansion pad flat tape is arranged.
[0035] The filling body formed by the expansion of the expansion pad flat tape after the jelly-roll formation is in close contact with the head end of the inner pole piece of the jelly-roll at the position where the expansion pad flat tape is arranged.
[0036] The distance between the corner point of the inner pole piece of the inner side of the corner of the jelly-roll and the head end of the inner pole piece of the jelly-roll at the position is 2-5 mm, the width of the expansion pad flat tape (a section shown in the picture) is less than the distance, and the length of the adhesive tape (perpendicular to the paper surface in the picture) = the width of the pole piece + 1-2 mm.
[0037] The inner corner of the jelly-roll is the inner corner of the first fold or the second fold of the jelly-roll, and the inner side of the inner corner of the jelly-roll has the head end of the inner pole piece.
[0038] In some embodiments, the outer side of the jelly-roll structure is provided with an end protection tape, and the end protection tape is located at the end of the pole piece of the jelly-roll. The end protection tape is attached to the outermost circle of the jelly-roll to prevent displacement of the pole piece.
[0039] The end protection tape forms a smooth connection between the end of the pole piece of the jelly-roll and the outer side of the pole piece of the jelly-roll.
[0040] In some embodiments, the area of the end protection tape of the jelly-roll is less than the actual compression area of the jelly-roll, and the length of the end protection tape (perpendicular to the paper surface in the picture) is not greater than the width of the pole piece.
[0041] At the end of the pole piece of the jelly-roll, if there is no other end of the pole piece of the jelly-roll inside, the end protection tape connects the outer side of the end of the pole piece of the jelly-roll to the pole piece in front of the end of the pole piece of the jelly-roll; at the end of the pole piece of the jelly-roll, if there is other end of the pole piece of the jelly-roll inside, the end protection tape connects the outer side of the end of the pole piece of the jelly-roll to the pole piece in front of the other end of the pole piece of the jelly-roll inside.
[0042] The expansion pad flat tape of the present application uses a heat expansion tape, such as a heat expansion tape with TPU as the base on the market, and the adhesive used is mainly modified acrylate. The total thickness of the heat expansion tape is 20-40 um, the thickness of the base is 8-16 um, and the thickness will expand at high temperature. After expansion, the total thickness is between 40-80 um.
[0043] The end protection tape of the present application uses a general adhesive tape.
[0044] In some embodiments, the battery cell of the present application is prepared as follows:
[0045] The positive electrode sheet uses 8-15 um aluminum foil as the base material, and is coated with positive electrode powder. The thickness of the positive electrode sheet is 60-180 um, the width of the positive electrode sheet after slitting is 20-150 mm, and the length of the positive electrode sheet powder is 0.6-3 m. The negative electrode sheet uses 4-8 um copper foil as the base material, and is coated with negative electrode powder. The thickness of the negative electrode sheet is 60-180 um, the width of the negative electrode sheet after slitting is 20-150 mm, and the length of the negative electrode sheet powder is 0.6-3 m.
[0046] The positive electrode sheet powder site corresponds to the negative electrode material, and the width of the separator is 1.5-3.0 mm less than the width of the negative electrode sheet after slitting. The width of the negative electrode sheet after slitting is 1.0-3.0 mm less than the width of the positive electrode sheet after slitting. The thickness of the separator is 5-18 um, and the positive and negative electrode sheet sites are all separated by the separator, which completely covers the positive and negative electrode sheets in the length and width directions.
[0047] The pressure formation process of the battery production is as follows: the formation temperature is 70-90℃, the formation pressure is (10-20) kgf / cm 2 , and the formation time is 0.5-4 h.
[0048] The following will be further described in detail in combination with the drawings and specific examples:
[0049] Example 1
[0050] As Figure 1 shown, the roll core A is spirally wound in the form of positive and negative electrode overlap, and the roll core A structure includes positive electrode sheet 1, negative electrode sheet 2, separator, first corner expansion pad flat tape 3, second corner expansion pad flat tape 4, and first end protection tape 9. The thickness of the expansion pad flat tape before expansion is 30 um.
[0051] The first corner expansion pad flat tape 3 is attached to the electrode powder coating area at the first left corner of the roll core; the second corner expansion pad flat tape 4 is attached to the electrode powder coating area at the first right corner of the roll core. The position of the electrode sheet head in the roll core is used for positioning, and the roll core is disassembled to confirm that the tape is pasted at the first corner gap. Subsequent production is positioned according to the size to ensure the quality and stability of production. Figure 1 The corner expansion pad flat tape is observed from the perspective direction, and the tape pasting position can be visually inspected to reduce the probability of incorrect tape pasting position.
[0052] Further in the formation process, the battery is formed by charging and discharging activation at a formation temperature of about 80℃, and the formation time is 2 h. The corner expansion pad flat tape swells in the high-temperature environment of the formation, and the thickness of the tape in the thickness direction based on the thickness of the tape itself swells. The total thickness after swelling is 80 um, which fills the corner gap. As Figure 2As shown, the expanded positive electrode sheet corner expansion pad flat tape 5 and the expanded second corner expansion pad flat tape 6 swell and expand to fill the corner gap under the high-temperature environment in the battery formation process, thereby balancing and supporting the internal structure of the battery, and reducing the problems of drum edge, arching, and unevenness on the surface of the battery during use.
[0053] The core of the embodiment 1 is also provided with a first end protection tape 9 connecting the end outside of the core electrode sheet tail end and the electrode sheet in front of the core electrode sheet tail end, which prevents the displacement of the electrode sheet by attaching the end protection tape to the outermost circle of the core.
[0054] Embodiment 2
[0055] As Figure 3 The core structure B comprises the wound positive electrode sheet 1, negative electrode sheet 2, separator, third corner expansion pad flat tape 7, and core end protection tape.
[0056] The third corner expansion pad flat tape 7 is attached to the powder coating area of the electrode sheet at the second left corner of the core. The tape attachment position is confirmed and the formation process is performed in the same way as in embodiment 1. Figure 4 As shown, the expanded third corner expansion pad flat tape 8 swells and expands to fill the corner gap under the high-temperature environment.
[0057] The core of the embodiment 2 is also provided with a second end protection tape 10 connecting the end outside of the core electrode sheet tail end and the electrode sheet in front of the core electrode sheet tail end, and a third end protection tape 11 connecting the end outside of the core electrode sheet tail end and the electrode sheet in front of the other core electrode sheet tail end inside, and the combination of the two end protection tapes makes the structure of the core electrode sheet more stable.
[0058] The above is only a preferred embodiment of the present application, and does not limit the present application in any form. Any skilled person in the art, without departing from the technical solution of the present application, according to the technical essence of the present application, any simple modification, equivalent replacement and improvement of the above embodiment, all still belong to the protection scope of the technical solution of the present application.
Claims
1. A lithium-ion battery core, characterized in that: It includes a positive electrode sheet, a negative electrode sheet, and a separator, wherein the positive electrode sheet, the negative electrode sheet, and the separator are wound into a core structure; In the aforementioned core structure, an expansion padding tape is provided on the electrode sheet at the corner position inside the core. The expansion padding tape can expand after the core is formed to form a filler that fills the corner position inside the core structure. The electrode with expansion pad tape at the corner position inside the core is either a positive electrode or a negative electrode. The expansion pad tape is placed on the electrode powder layer on the side of the electrode head end inside the core, inside the corner position.
2. The lithium-ion battery core according to claim 1, characterized in that: The expansion pad flat tape is staggered with the inner electrode head of the core where the expansion pad flat tape is installed; the filler formed by the expansion pad flat tape after the core is formed is closely attached to the inner electrode head of the core where the expansion pad flat tape is installed.
3. The lithium-ion battery core according to claim 1, characterized in that: The distance between the corner point of the electrode sheet on the inner side of the inner corner of the core and the head end of the inner electrode sheet on the inner side of the core is 2-5mm, and the width of the expansion pad tape is less than this distance.
4. The lithium-ion battery core according to claim 1, characterized in that: The inner corner of the core is the inner corner of the first fold or the second fold of the core, and the inner side of the inner corner of the core has the inner pole end of the core.
5. The lithium-ion battery core according to claim 1, characterized in that: The outer side of the core structure is provided with a protective tape for finishing, which is located at the finishing end of the core electrode sheet.
6. The lithium-ion battery core according to claim 5, characterized in that: The aforementioned protective tape at the end creates a smooth connection between the end of the core electrode sheet and the outer surface of the core electrode sheet.
7. The lithium-ion battery core according to claim 6, characterized in that: At the end of the core electrode sheet, if there are no other core electrode sheet ends on its inner side, the protective tape connects the outer side of the end of the core electrode sheet to the electrode sheet in front of the end of the core electrode sheet; if there are other core electrode sheet ends on its inner side, the protective tape connects the outer side of the end of the core electrode sheet to the electrode sheet in front of the other core electrode sheet ends on its inner side.
8. The lithium-ion battery core according to claim 1, characterized in that: The expansion pad tape mentioned above is a heat-expanding tape.
9. The lithium-ion battery core according to claim 5, characterized in that: The protective tape used for finishing the process is ordinary tape.
10. A lithium-ion battery, characterized in that: Contains a lithium-ion battery core as described in any one of claims 1-9.