Battery cell winding structure, cylindrical battery monomer and battery pack

Abstract

The utility model provides a battery core winding structure, a cylindrical battery monomer and a battery pack, and belongs to the technical field of batteries, the battery core winding structure comprises a winding battery core body, the winding battery core body comprises pole pieces and diaphragms, the pole pieces comprise a positive pole piece and a negative pole piece, and the diaphragms comprise a first diaphragm and a second diaphragm; the wound battery cell body is formed by winding a negative plate, a first diaphragm, a positive plate and a second diaphragm which are stacked in sequence; the adhesive tape body is attached to the ending end of the outermost pole piece of the winding battery cell body, and the viscosity of the adhesive tape body is increased along with the temperature rise of the winding battery cell body; and the green glue wraps the peripheral surface of the winding battery cell body. The battery has the beneficial effects that the adhesive tape body is attached to the ending end of the outermost pole piece of the wound battery cell, and the viscosity of the adhesive tape body can be increased along with temperature rise, so that the binding force of the outermost pole piece can be directly enhanced, and the outer ring looseness caused by repeated expansion of the battery cell in the charging and discharging process of the battery cell is prevented; and the problem of lithium-ion chromatography outside the battery core caused by increase of the distance between the pole pieces is avoided.

Description

Technical Field

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

[0002] The core winding structure is formed by winding materials such as positive electrode sheets, negative electrode sheets, and separators in a certain order and process requirements to form a wound core (or called a bare core) with a specific shape and size. It is widely used in cylindrical or square lithium-ion batteries and is one of the key links in the battery manufacturing process.

[0003] As Figure 1 shown, the current end process of the core winding structure is usually to make the separator extend one or two circles longer than the negative electrode sheet, and wind the separator one or two extra circles during the winding end, and then use green glue to attach it to the end position of the separator. The length of the green glue is usually slightly less than the circumference of the wound core to ensure that it can tightly wrap the surface of the bare core.

[0004] However, in this end method, the green glue is directly attached to the separator, and its binding force mainly acts on the separator itself, rather than effectively fixing the end of the outermost electrode sheet directly. This results in that after the battery undergoes multiple charge and discharge cycles, the outermost electrode sheet of the core is prone to loosen due to lack of sufficient binding force, thereby affecting the overall performance and stability of the battery. In addition, as a material with large elasticity, the separator will deform with the expansion and contraction of the electrode sheet during the charge and discharge process of the core, resulting in the relaxation of the separator itself, thereby reducing the binding effect of the separator on the outermost positive and negative electrode sheets, and even may cause the increase of the distance between the outermost electrode sheets and problems such as lithium deposition. Content of the Utility Model

[0005] In order to solve the above technical problems, the utility model provides a core winding structure, a cylindrical battery cell, and a battery pack.

[0006] The technical problems solved by the utility model can be realized by the following technical solutions:

[0007] A core winding structure, comprising:

[0008] A wound core body, comprising electrode sheets and a separator. The electrode sheets include a positive electrode sheet and a negative electrode sheet. The separator includes a first separator and a second separator. The wound core body is wound by sequentially stacking the negative electrode sheet, the first separator, the positive electrode sheet, and the second separator;

[0009] A tape body, the tape body is attached to the end of the outermost electrode sheet of the wound core body, and the viscosity of the tape body increases with the increase of the temperature of the wound core body;

[0010] Green glue, and the green glue is wrapped around the outer peripheral surface of the wound battery cell body.

[0011] Preferably, the outermost electrode sheet of the wound battery cell body is the positive electrode sheet.

[0012] Preferably, the tape body is hot melt adhesive.

[0013] Preferably, the hot melt adhesive includes double-sided hot melt adhesive.

[0014] Preferably, the double-sided hot melt adhesive includes an opposite first side and a second side. The first side is attached to the end of the positive electrode sheet and the first separator, and the second side is attached to the second separator.

[0015] Preferably, during baking or charge and discharge of the wound battery cell body, the temperature of the wound battery cell body rises, and the viscosity of the tape body increases.

[0016] Preferably, the length of the green glue is less than the circumference of the wound battery cell body.

[0017] Preferably, the number of winding turns of the separator is more than the number of winding turns of the electrode sheet.

[0018] The present invention also provides a cylindrical battery cell, and the cylindrical battery cell includes a battery housing, and the above-mentioned battery cell winding structure is installed in the battery housing.

[0019] The present invention also provides a battery pack, and a plurality of the above-mentioned cylindrical battery cells are integrated in the battery pack.

[0020] The advantages or beneficial effects of the technical solution of the present utility model are as follows:

[0021] By attaching the tape body to the end of the outermost electrode sheet of the wound battery cell, and the viscosity of the tape body increases with the increase of temperature, the present utility model can directly enhance the binding force of the outermost electrode sheet, prevent the outer ring from loosening caused by the repeated expansion of the battery cell during the charge and discharge process of the battery cell, and thus avoid the problem of lithium deposition on the outer layer of the battery cell caused by the increase of the electrode sheet spacing. Description of the Drawings

[0022] Figure 1 It is a schematic structural diagram of a battery cell winding structure in the prior art; Figure 1 The green line represents the separator, the black line represents the negative electrode sheet, and the orange line represents the positive electrode sheet;

[0023] Figure 2 It is a schematic structural diagram of a cylindrical battery cell in a preferred embodiment of the present utility model; Figure 2 In it, the yellow line represents the negative electrode sheet, the blue line represents the positive electrode sheet, the black line represents the separator, and the green line represents the green glue;

[0024] Figure 3 In a preferred embodiment of the present utility model, it is a schematic diagram of the appearance of hot melt adhesive application.

[0025] Figure 4 In a preferred embodiment of the present utility model, it is a schematic diagram of double-sided hot melt adhesive application.

[0026] Explanation of reference numerals in the drawings:

[0027] 1. Wound battery cell body; 2. Positive electrode sheet; 3. Negative electrode sheet; 4. First separator; 5. Second separator; 6. Tape body; 7. Green glue; 8. Battery housing. Specific embodiments

[0028] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present utility model.

[0029] It should be noted that, without conflict, the embodiments in the present utility model and the features in the embodiments can be combined with each other.

[0030] Next, the present utility model will be further described in conjunction with the accompanying drawings and specific embodiments, but it is not a limitation of the present utility model.

[0031] See Figure 2 、 Figure 3 and Figure 4 , in a preferred embodiment of the present utility model, based on the above problems existing in the prior art, a battery cell winding structure for enhancing the binding force of the outermost electrode sheet is provided, including:

[0032] A wound battery cell body 1, including electrode sheets and separators. The electrode sheets include a positive electrode sheet 2 and a negative electrode sheet 3, and the separators include a first separator 4 and a second separator 5. The wound battery cell body 1 is wound by sequentially stacking a negative electrode sheet 3, a first separator 4, a positive electrode sheet 2, and a second separator 5;

[0033] A tape body 6, which is attached to the end of the outermost electrode sheet of the wound battery cell body 1, and the viscosity of the tape body 6 increases as the temperature of the wound battery cell body 1 rises;

[0034] Green glue 7, which wraps around the outer peripheral surface of the wound battery cell body 1.

[0035] Specifically, the embodiment of the present utility model provides a new method of applying adhesive tape during the finishing process of the core winding structure. By applying the tape body 6 to the end of the outermost pole piece of the wound core, the binding force can be directly applied to the outermost pole piece of the wound core, preventing the outer ring from loosening due to the repeated expansion of the core during the charging and discharging process of the core, thereby avoiding the problem of lithium deposition on the outer layer of the core caused by the increase in the pole piece spacing.

[0036] Meanwhile, in the subsequent production process of the core, as the temperature of the tape body 6 increases, its viscosity will increase, realizing the enhancement of the adhesive force of the applied tape and further enhancing the binding force of the outermost pole piece.

[0037] As a preferred embodiment, the outermost pole piece of the wound core body 1 is the positive pole piece 2.

[0038] Specifically, the tape body 6 is directly applied to the end position of the positive pole piece 2 of the wound core, bonding the positive pole piece 2 and the wound core body 1. Since the tape body 6 is directly applied to the positive pole piece 2, its binding force will directly act on the positive pole piece 2, and the end pole piece can be directly bound.

[0039] As a preferred embodiment, the tape body 6 is a hot melt adhesive.

[0040] As a preferred embodiment, the hot melt adhesive includes a double-sided hot melt adhesive.

[0041] As a preferred embodiment, the double-sided hot melt adhesive includes an opposite first side and a second side. The first side is applied to the end of the positive pole piece 2 and the first separator 4, and the second side is applied to the second separator 5.

[0042] Specifically, the double-sided hot melt adhesive is applied to the end position of the outermost positive pole piece 2 of the wound core. The first side of the double-sided hot melt adhesive is applied to the end of the positive pole piece 2 and the outer side of the inner ring separator, and the second side of the double-sided hot melt adhesive is applied to the inner side of the outer ring separator.

[0043] The first separator 4 is the inner ring separator, and the second separator 5 is the outer ring separator.

[0044] The inner side is the side facing the center of the wound core, and the outer side is the side facing away from the center of the wound core.

[0045] As a preferred embodiment, during the baking or charging and discharging process of the wound core body 1, as the temperature of the wound core body 1 increases, the viscosity of the tape body 6 increases.

[0046] Specifically, during the subsequent baking process of the battery cell, under the action of high temperature, the viscosity of the hot melt adhesive increases, thereby increasing the adhesion between the positive electrode sheet 2 and the inner and outer separators, enhancing the restraint of the end of the positive electrode sheet 2, preventing the outer ring from loosening due to the repeated expansion of the battery cell during the charge and discharge process of the battery cell, and avoiding the problem of lithium plating on the outer layer of the battery cell due to the increase in the distance between the electrode sheets.

[0047] During the charge and discharge process of the battery, as the temperature of the wound battery cell body 1 increases, the viscosity of the hot melt adhesive also increases, thereby increasing the adhesion between the positive electrode sheet 2 and the inner and outer separators, enhancing the restraint of the outermost electrode sheet of the wound battery cell, preventing the outer ring from loosening due to the repeated expansion of the battery cell during the charge and discharge process of the battery cell, and avoiding the problem of lithium plating on the outer layer of the battery cell due to the increase in the distance between the electrode sheets.

[0048] As a preferred embodiment, the length of the green adhesive 7 is less than the circumference of the wound battery cell body 1.

[0049] As a preferred embodiment, the number of winding turns of the separator is more than the number of winding turns of the electrode sheet.

[0050] Specifically, the separator is one or two turns longer than the positive electrode sheet. The winding end separator winds one or two turns, and then the green adhesive is pasted to the end position of the separator. The length of the green adhesive is slightly less than the circumference of the cylindrical battery cell, so that the green adhesive can wrap the bare battery cell.

[0051] The present invention also provides a cylindrical battery cell. The cylindrical battery cell includes a battery housing 8, and the battery housing 8 is internally provided with a battery cell winding structure as described above.

[0052] The present invention also provides a battery pack, and a plurality of cylindrical battery cells as described above are integrated in the battery pack.

[0053] The advantages or beneficial effects of adopting the above technical solutions are as follows: By pasting the tape body at the end of the outermost electrode sheet of the wound battery cell, and the viscosity of the tape body increases with the increase of temperature, the restraint force of the outermost electrode sheet can be directly enhanced, preventing the outer ring from loosening due to the repeated expansion of the battery cell during the charge and discharge process of the battery cell, thereby avoiding the problem of lithium plating on the outer layer of the battery cell due to the increase in the distance between the electrode sheets.

[0054] The above are only the preferred embodiments of the present invention, and do not limit the implementation manners and protection scope of the present invention. For those skilled in the art, it should be realized that all equivalent replacements and obvious changes made by using the content of this specification and the drawings should be included in the protection scope of the present invention.

Claims

1. A core winding structure, characterized in that, Comprising: A wound cell body, the wound cell body comprising electrode sheets and a separator, the electrode sheets comprising a positive electrode sheet and a negative electrode sheet, the separator comprising a first separator and a second separator, the wound cell body being wound from the negative electrode sheet, the first separator, the positive electrode sheet, and the second separator stacked in sequence; A tape body, the tape body being attached to the end of the outermost electrode sheet of the wound cell body, and the viscosity of the tape body increasing as the temperature of the wound cell body rises; Green glue, the green glue being wrapped around the outer peripheral surface of the wound cell body.

2. The core winding structure according to claim 1, wherein The outermost electrode sheet of the wound cell body is the positive electrode sheet.

3. The core winding structure according to claim 1, characterized in that The tape body is a hot melt adhesive.

4. The core winding structure according to claim 3, wherein, The hot melt adhesive includes a double-sided hot melt adhesive.

5. The core winding structure according to claim 4, wherein, The double-sided hot melt adhesive includes opposite first and second surfaces, the first surface being attached to the end of the positive electrode sheet and the first separator, and the second surface being attached to the second separator.

6. The core winding structure according to claim 1, wherein During baking or charge and discharge of the wound cell body, the temperature of the wound cell body rises, and the viscosity of the tape body increases.

7. The core winding structure according to claim 1, characterized in that, The length of the green glue is less than the circumference of the wound cell body.

8. The core winding structure according to claim 1, wherein The number of winding turns of the separator is more than the number of winding turns of the electrode sheet.

9. A cylindrical battery cell, characterized in that, The cylindrical battery cell includes a battery housing, and the cell winding structure according to any one of claims 1-8 is installed inside the battery housing.

10. A battery pack, characterized in that, A plurality of cylindrical battery cells according to claim 9 are integrated in the battery pack.

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