Cylindrical roll core structure and cylindrical battery

Abstract

The utility model relates to the technical field of batteries, and discloses a cylindrical roll core structure and a cylindrical battery. The cylindrical roll core structure comprises a pole piece assembly and a supporting assembly. The pole piece assembly is wound into a cylindrical winding core, and the winding core is provided with a plurality of winding layers along the radial direction; the supporting assembly comprises a plurality of arc-shaped supporting frames, and the multiple supporting frames are arranged around the center axis of the roll core and cover the whole circumference; the supporting frames are located between the adjacent winding layers. According to the utility model, the supporting assembly is arranged in the winding layer of the winding core, and a plurality of supporting frames in the supporting assembly are used as a stable supporting structure, so that a rigid supporting effect can be achieved on the pole piece assembly in a normal charging and discharging process, a rigid constraint is provided in the middle of the battery, and uneven interlayer expansion is improved; reduction of electric performance and safety performance in the later period of battery circulation is avoided; compared with a roll core structure of a cylindrical battery in the prior art, the roll core structure can improve the infiltration performance of a battery electrolyte and comprehensively improve the electrical performance and the safety performance of the battery.

Description

Technical Field

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

[0002] Because lithium-ion batteries have the advantages of good rate performance, high safety, large capacity, long cycle life, and green environmental protection, cylindrical lithium-ion batteries have a symmetrical structure, strong flexibility in system integration design, simple structure, and low structural component cost, and are widely used in consumer, power, and energy storage fields.

[0003] However, current cylindrical batteries have problems such as slow electrolyte infiltration, uneven absorption and expansion, which affect the performance of the battery. In particular, larger cylindrical batteries have many winding layers, uneven tension, uneven electrolyte absorption and infiltration, and uneven expansion, which seriously restricts the development and application of cylindrical batteries. Utility Model Content

[0004] In view of this, the utility model provides a cylindrical winding core structure and a cylindrical battery to solve the problems of uneven liquid absorption and uneven expansion of cylindrical batteries.

[0005] In the first aspect, the utility model provides a cylindrical winding core structure, including a pole piece assembly and a support assembly. The pole piece assembly is wound into a cylindrical winding core, and the winding core has multiple winding layers along the radial direction; the support assembly includes multiple arc-shaped support frames, and the multiple support frames are arranged around the central axis of the winding core and cover the entire circumference; the support frames are located between adjacent winding layers.

[0006] Beneficial effects: By arranging a support assembly in the winding layer of the core, the multiple support frames in the support assembly serve as a stable support structure, which can provide rigid support for the electrode assembly during normal charging and discharging, provide a rigid constraint in the middle of the battery, improve uneven expansion between layers, and avoid the degradation of electrical performance and safety performance in the later stage of battery cycle; compared with the core structure of cylindrical batteries in related technologies, it can improve the wetting performance of battery electrolyte and comprehensively improve the electrical performance and safety performance of the battery.

[0007] In an optional embodiment, along the circumference of the winding core, the sector-shaped areas corresponding to adjacent support frames do not overlap.

[0008] In an optional embodiment, among the multiple support frames, at least two support frames have different radii.

[0009] In an optional embodiment, the support frame includes an inner layer support and an outer layer support, and the two ends of the inner layer support and the outer layer support are connected along the circumference of the support frame; there is a gap between the inner layer support and the outer layer support, and along the axial direction of the support frame, the gap runs through the two ends of the support frame; the support frame is made of expandable material, and the support frame is suitable for radial and / or axial expansion along the core.

[0010] In an optional embodiment, the inner layer support and / or the outer layer support is provided with a plurality of through holes, and the through holes are connected to the gap.

[0011] In an optional embodiment, the through hole is filled with a lithium supplement.

[0012] In an optional embodiment, at least one liquid-absorbing layer is provided in the gap.

[0013] In an optional embodiment, the electrode assembly includes a positive electrode sheet, a negative electrode sheet and a separator, the separator is located between the positive electrode sheet and the negative electrode sheet; a support frame is arranged between the positive electrode sheet and the separator, and / or the support frame is arranged between the negative electrode sheet and the separator; in a winding layer provided with a support frame, along the circumferential direction, the separator includes a conventional segment corresponding to the position of the support frame and a thickened segment offset from the support frame, the thickness of the thickened segment is greater than the thickness of the conventional segment, and the conventional segment and the thickened segment form a whole circle.

[0014] In an optional embodiment, along the thickness direction of the isolation membrane, the thickened section of the isolation membrane includes a base membrane and a conventional coating and / or a functional coating provided on the surface of the base membrane, and the functional coating includes a polymer bonding layer, a gas generating layer or a thermal insulation layer.

[0015] In a second aspect, the utility model also provides a cylindrical battery, comprising a shell, a cover plate assembly, and a cylindrical winding core structure of any one of the above technical solutions. The shell is cylindrical, and the shell is provided with an open end; the cover plate assembly is provided at the open end of the shell; and the cylindrical winding core structure is encapsulated in the shell by the cover plate assembly.

[0016] Beneficial effect: Because the cylindrical battery includes a cylindrical core structure, it has the same effect as the cylindrical core structure and will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 A radial cross-sectional view of a cylindrical winding core structure according to an embodiment of the utility model;

[0019] Figure 2 A schematic diagram of the structural distribution of a support frame in a support assembly;

[0020] Figure 3 It is another schematic diagram of the structural distribution of the support frame in the support assembly;

[0021] Figure 4 is a schematic diagram of the three-dimensional structure of the support frame before expansion;

[0022] Figure 5 for Figure 4 A top view of the support frame shown;

[0023] Figure 6 for Figure 4 The three-dimensional structure schematic diagram of the support frame after expansion is shown;

[0024] Figure 7 It is a schematic diagram of the structure of the thickened section of the isolation membrane.

[0025] Description of reference numerals:

[0026] 1. Pole plate assembly; 11. Positive electrode plate; 12. Negative electrode plate; 13. Isolation film; 131. Base film; 132. Conventional coating; 133. Functional coating; 14. Rolling adhesive tape; 2. Support assembly, 21. Support frame; 211. Inner support; 212. Outer support; 213. Through hole; 214. Liquid absorption layer; 215. Gap. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the utility model.

[0028] Combine the following Figures 1 to 7 , describing an embodiment of the utility model.

[0029] According to an embodiment of the utility model, on the one hand, a cylindrical winding core structure is provided, comprising a pole piece assembly 1 and a support assembly 2. The pole piece assembly 1 is wound into a cylindrical winding core, and the winding core has multiple winding layers along the radial direction; the support assembly 2 comprises multiple arc-shaped support frames 21, and the multiple support frames 21 are arranged around the central axis of the winding core and cover the entire circumference; the support frames 21 are located between adjacent winding layers.

[0030] By arranging a support assembly 2 in the winding layer of the winding core, the multiple support frames 21 in the support assembly 2 serve as a stable support structure, which can provide a rigid support for the pole piece assembly 1 during normal charging and discharging, provide a rigid constraint in the middle of the battery, improve uneven expansion between layers, and avoid the degradation of electrical performance and safety performance of the battery in the later stage of the cycle; compared with the winding core structure of the cylindrical battery in the related technology, it can improve the wetting performance of the battery electrolyte and comprehensively improve the electrical performance and safety performance of the battery.

[0031] Since a plurality of support frames 21 are provided, the plurality of support frames 21 are arranged around the central axis of the winding core and can cover the entire circumference, thus ensuring that the expansion unevenness between winding layers of the winding core can be improved along the radial direction on the entire circumference.

[0032] It should be noted that the “plurality” here includes two.

[0033] Regarding “multiple support frames 21 are arranged around the central axis of the winding core and cover the entire circumference”, the “entire circumference” mentioned here means that when different winding layers are inserted into the support frames 21, the central angle of all the support frames 21 around the center of the circle can reach 360°, such as Figure 2 or Figure 3 shown.

[0034] Regarding “the support frame 21 is located between adjacent winding layers”, specifically, the electrode assembly 1 includes a positive electrode sheet 11, a negative electrode sheet 12 and a separator 13, and the separator 13 is located between the positive electrode sheet 11 and the negative electrode sheet 12; the support frame 21 is located between adjacent winding layers including the positive electrode sheet 11 and the negative electrode sheet 12. Figure 1 In the cylindrical winding core structure shown, the winding layer located at the outer peripheral portion does not have a positive electrode sheet 11 or a negative electrode sheet 12, and at this time there is no support frame 21.

[0035] The pole piece assembly is wound to form a winding core, and the end is fixed with a winding adhesive tape 14.

[0036] As one embodiment, a plurality of support frames 21 are respectively disposed at different winding layers.

[0037] In some embodiments, along the circumference of the winding core, the sector-shaped areas corresponding to adjacent support frames 21 do not overlap.

[0038] By arranging the sector-shaped areas corresponding to the adjacent support frames 21 to be non-overlapping, it is possible to ensure that the adjacent ends of the two support frames 21 do not overlap in the radial direction, thereby ensuring that the thickness of each winding layer is uniform.

[0039] In some embodiments, Figure 2 As shown, among the multiple support frames 21, there are at least two support frames 21 with different radii.

[0040] The radii of the two support frames 21 are different, that is, along the radial direction of the winding core, the two support frames 21 are distributed in different winding layers. In this way, along the radial direction, from the center of the winding core to the outer layer, the infiltration effect of the electrolyte can be improved.

[0041] In some embodiments, Figure 3 As shown, the radii of the multiple support frames 21 are not equal, so that along the radial direction, from the center of the winding core to the outer layer, the electrolyte infiltration effect can be improved as much as possible, while alleviating the electrical performance failure of the battery caused by uneven expansion on the radial gradient.

[0042] In some embodiments, along the radial direction of the winding core, a plurality of support frames 21 are evenly spaced and arranged at different winding layers.

[0043] In some embodiments, the support frame 21 includes an inner layer support 211 and an outer layer support 212. Along the circumference of the support frame 21, the two ends of the inner layer support 211 and the outer layer support 212 are connected; there is a gap 215 between the inner layer support 211 and the outer layer support 212, and along the axial direction of the support frame 21, the gap 215 runs through the two ends of the support frame 21; the support frame 21 is made of expandable material, and the support frame 21 is suitable for radial and / or axial expansion along the core.

[0044] Specifically, the support frame 21 is a double-layer structure with a gap 215 in the middle. The gap 215 can be used to circulate electrolyte and gas. In this way, the gap 215 between the inner layer support 211 and the outer layer support 212 helps the electrolyte to infiltrate along the axial and radial directions of the winding core, further improving the electrolyte infiltration rate.

[0045] In addition, the cylindrical battery in the related art has a tightly wound cell inside and a compact space between the cell and the shell, which generates a lot of heat and is difficult to dissipate, which can easily cause thermal runaway inside the battery and bring safety hazards. The cylindrical winding core structure provided in this embodiment has a support frame 21, and the support frame 21 has a gap 215. Under abnormal conditions such as thermal runaway, an exhaust channel can be provided during the thermal runaway of the battery. The gas generated by the battery can be quickly discharged and depressurized through the gap 215, thereby improving the safety and stability of the battery.

[0046] Furthermore, since the support frame 21 is made of expandable material, specifically, during the abnormal gas production process caused by heat inside the battery, the support frame 21 expands due to heat, and the gap 215 is further enlarged to form a larger exhaust channel, thereby accelerating exhaust and improving the safety performance of the battery cell.

[0047] Specifically, the material of the support frame 21 includes polypropylene, polyurethane, expandable graphite, inorganic oxide, or metal.

[0048] In some embodiments, the inner support 211 and / or the outer support 212 are provided with a plurality of through holes 213 , and the through holes 213 are connected to the gaps 215 .

[0049] With this arrangement, ions can be transported between winding layers through the through holes 213 on the support frame 21, and the gaps 215 of the support frame 21 provide a path for electrolyte infiltration and abnormal gas exhaust. Specifically, the electrolyte at the head and top of the battery can diffuse downward through the gaps 215, and further diffuse laterally from the through holes 213, thereby improving the electrolyte infiltration performance and improving the consistency of the electrolyte infiltration of the pole pieces between the winding layers of the battery, thereby improving the electrical performance of the battery.

[0050] At the same time, during the abnormal gas production process caused by heat inside the battery, the support frame 21 expands due to the heat, the through hole 213 on the support frame 21 expands, the inner layer support 211 and the outer layer support 212 expand, the gap 215 expands, and the abnormal gas enters the gap 215 through the through hole 213. The gas is transported from the middle of the support frame 21 to the top or bottom of the battery, and reaches the vicinity of the battery explosion-proof valve, which is depressurized and exhausted in time to avoid the accumulation of combustible gas under internal overheating conditions and cause fire and explosion.

[0051] In some embodiments, the through hole 213 is filled with a lithium supplement.

[0052] By filling the lithium supplement agent in the through hole 213, the active lithium can be supplemented in the middle and late stages of the cycle, thereby improving the cycle performance of the battery cell.

[0053] In some embodiments, at least one liquid absorbing layer 214 is disposed in the gap 215 .

[0054] By arranging the liquid absorption layer 214 in the gap 215, the liquid absorption layer 214 can absorb electrolyte into the gap 215 along the axial direction, and the electrolyte in the liquid absorption layer 214 is squeezed out during the charge and discharge process, which is more conducive to the uniform distribution of the electrolyte during the charge and discharge process.

[0055] Specifically, the liquid absorbing layer 214 may be composited on the inner layer support 211 and / or the outer layer support 212 .

[0056] The material used for the liquid absorbing layer 214 includes chemical liquid absorbing cotton or polyurethane sponge.

[0057] In some embodiments, the electrode assembly 1 includes a positive electrode sheet 11, a negative electrode sheet 12 and an isolation membrane 13, wherein the isolation membrane 13 is located between the positive electrode sheet 11 and the negative electrode sheet 12; the support frame 21 is arranged between the positive electrode sheet 11 and the negative electrode sheet 12, specifically, the support frame 21 is arranged between the positive electrode sheet 11 and the isolation membrane 13, and / or, the support frame 21 is arranged between the negative electrode sheet 12 and the isolation membrane 13; in the winding layer provided with the support frame 21, along the circumferential direction, the isolation membrane 13 includes a conventional segment corresponding to the position of the support frame 21 and a thickened segment offset from the support frame 21, the thickness of the thickened segment is greater than the thickness of the conventional segment, and the conventional segment and the thickened segment form a whole circle.

[0058] Specifically, the support frame 21 is located in the winding layer where the isolation membrane 13 is located. The conventional section of the isolation membrane 13 is the isolation membrane 13 in the related art. The thickened section is different from the conventional section. The thickness of the thickened section is greater than that of the conventional section, which can make up for the thickness difference between the position with the support frame 21 and the position without the support frame 21 in the same winding layer, avoiding uneven ion transmission caused by the thickness difference. On the other hand, by setting the functional coating 133, other functions can be brought.

[0059] In some embodiments, along the thickness direction of the isolation membrane 13, the thickened section of the isolation membrane 13 includes a base membrane 131 and a conventional coating 132 and / or a functional coating 133 provided on the surface of the base membrane 131, and the functional coating 133 includes a polymer bonding layer, a gas generating layer or a thermal insulation layer.

[0060] Conventional coating 132 is a coating used for separator 13 in related art. By providing a polymer bonding layer, the interface contact consistency and stability can be improved. By providing a gas generating layer, non-flammable gas can be generated when the battery is heated, forming a gas layer between the pole pieces, blocking the ion transmission channel, and preventing the battery from further deteriorating and causing thermal runaway.

[0061] The heat-insulating layer can play a role in heat insulation and insulation. During the process of heating and gas generation of the battery, it can prevent the isolation film 13 from being heated and shrinking prematurely, causing a short circuit, and can further enhance the safety performance of the battery.

[0062] In some embodiments, the pole pieces located on the inner and outer sides of the support frame 21 are both single-sided coated, and the positive pole piece 11 and the negative pole piece 12 are not coated with active materials on the side facing the support frame 21, so as to avoid the support frame 21 physically blocking the transmission of electrons and affecting the performance of the battery cell.

[0063] According to an embodiment of the utility model, on the other hand, a cylindrical battery is provided, comprising a shell, a cover plate assembly and a cylindrical winding core structure of any one of the above technical solutions. The shell is cylindrical and has an open end; the cover plate assembly is arranged at the open end of the shell; and the cylindrical winding core structure is encapsulated in the shell by the cover plate assembly.

[0064] Because the cylindrical battery includes a cylindrical core structure, it has the same effect as the cylindrical core structure and will not be described in detail here.

[0065] Although the embodiments of the present invention are described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A cylindrical winding core structure, characterized in that: include: A pole piece assembly (1), the pole piece assembly (1) being wound into a cylindrical winding core, the winding core having a plurality of winding layers in a radial direction; A support assembly (2), the support assembly (2) comprising a plurality of arc-shaped support frames (21), the plurality of support frames (21) being arranged around the central axis of the winding core and covering the entire circumference; the support frames (21) being located between adjacent winding layers.

2. The cylindrical winding core structure according to claim 1, characterized in that: Along the circumference of the winding core, the sector-shaped areas corresponding to adjacent support frames (21) do not overlap.

3. The cylindrical winding core structure according to claim 1 or 2, characterized in that: Among the plurality of support frames (21), at least two of the support frames (21) have unequal radii.

4. The cylindrical winding core structure according to claim 1 or 2, characterized in that: The support frame (21) includes an inner layer support (211) and an outer layer support (212), and along the circumference of the support frame (21), the two ends of the inner layer support (211) and the outer layer support (212) are connected; there is a gap (215) between the inner layer support (211) and the outer layer support (212), and along the axial direction of the support frame (21), the gap (215) runs through the two ends of the support frame (21); the support frame (21) is made of expandable material, and the support frame (21) is suitable for expanding along the radial and / or axial direction of the winding core.

5. The cylindrical winding core structure according to claim 4, characterized in that: The inner layer support (211) and / or the outer layer support (212) are provided with a plurality of through holes (213), and the through holes (213) are communicated with the gap (215).

6. The cylindrical winding core structure according to claim 5, characterized in that: The through hole (213) is filled with a lithium supplement.

7. The cylindrical winding core structure according to claim 4, characterized in that: At least one liquid absorbing layer (214) is provided in the gap (215).

8. The cylindrical winding core structure according to claim 1 or 2, characterized in that: The electrode assembly (1) comprises a positive electrode (11), a negative electrode (12) and a separator (13), wherein the separator (13) is located between the positive electrode (11) and the negative electrode (12); the support frame (21) is arranged between the positive electrode (11) and the separator (13), and / or the support frame (21) is arranged between the negative electrode (12) and the separator (13); In the winding layer provided with the support frame (21), along the circumferential direction, the isolation membrane (13) includes a conventional segment corresponding to the position of the support frame (21) and a thickened segment offset from the support frame (21), the thickness of the thickened segment is greater than the thickness of the conventional segment, and the conventional segment and the thickened segment form a full circle.

9. The cylindrical winding core structure according to claim 8, characterized in that: Along the thickness direction of the isolation membrane (13), the thickened section of the isolation membrane (13) includes a base membrane (131) and a conventional coating (132) and / or a functional coating (133) arranged on the surface of the base membrane (131), and the functional coating (133) includes a polymer adhesive layer, a gas generating layer or a thermal insulation layer.

10. A cylindrical battery, characterized in that: include: A shell, the shell is cylindrical and has an open end; A cover plate assembly, the cover plate assembly being arranged at an open end of the shell; The cylindrical winding core structure according to any one of claims 1 to 9, wherein the cylindrical winding core structure is encapsulated in the shell by the cover plate assembly.

Images