Soft package battery corner lithium precipitation swelling prevention adhesive tape

Abstract

The utility model discloses a soft package battery corner lithium precipitation prevention swelling adhesive tape which comprises a base material, the base material is a swelling layer which can absorb swelling of battery electrolyte and is sticky to negative electrode slurry, one side of the swelling layer is compounded with an adhesive layer, the other side of the swelling layer is compounded with a release film layer, and therefore the composite swelling adhesive tape is formed. The swelling layer replaces an original diaphragm, after the swelling layer absorbs electrolyte and swells, the swelling layer has a little viscosity to the diaphragm and negative electrode slurry, since the electrolyte exists in the swelling layer after the swelling layer swells, the passing of LI + is not influenced, and the difference between the passing efficiency and the diaphragm is small; the proportion of an adhesive layer of the adhesive tape can be reduced by punching and the like, and the adhesive tape can be quickly and completely dissolved in a small amount of electrolyte; when the lithium ion battery is quickly charged, the adhesive tape is adhered to the inner layer of the wrap angle position, so that the transmission speed of lithium ions on the inner layer can be effectively reduced, the problem of lithium precipitation of a side wrap angle negative electrode of the battery is solved, and the fixation is reliable.

Description

Technical Field

[0001] The utility model relates to the technical field of battery tapes, in particular to a soft-pack battery corner anti-lithium swelling tape. Background Art

[0002] Currently, the charging process for lithium-ion batteries consists of two steps: the first is constant-current charging to the battery's maximum voltage, and the second is constant-voltage charging at that voltage. During constant-voltage charging, the current gradually decreases, and charging ends when the current reaches the set current. The constant-voltage charging phase is long and charges a small amount of capacity. The idea behind high-voltage overcharging is to reduce the constant-voltage charging ratio and increase the constant-current charging ratio. In lithium battery production, the separator is a key raw material. The quality of the separator determines the battery's interface structure and internal resistance, directly impacting characteristics such as rate capability, cycling performance, and safety. Separator thickness, porosity, and air permeability significantly influence the fast charging of lithium-ion batteries. Thin thickness, high porosity, and high air permeability minimize the barrier to lithium ion transfer from the positive electrode to the negative electrode, reducing polarization during charging. Separator thickness and porosity significantly influence the charging performance of lithium-ion batteries. When the battery is fast charged, when lithium ions are transferred from the positive electrode to the negative electrode through the diaphragm at the side corner of the battery, the transfer speed is too fast and too many lithium ions are transferred to the negative electrode, which makes it easy for lithium to be deposited at the side corner of the battery.

[0003] The current battery separator tape with a soluble adhesive layer has a poor effect in preventing subsequent lithium precipitation because the separator is not firmly fixed inside the battery and moves slowly after the adhesive layer dissolves. For example, patent CN117820972A discloses a double-sided protective tape for the welding part of the lithium-ion battery tab and its preparation method. One side of the substrate of the double-sided protective tape is a rubber layer, and the other side is a pressure-sensitive adhesive layer that can be dissolved in the electrolyte. Utility Model Content

[0004] In view of the shortcomings of the existing technology, the utility model provides a soft-pack battery corner anti-lithium precipitation swelling tape, so as to achieve the purpose of good anti-lithium precipitation effect on the soft-pack battery corner and reliable fixation.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] The soft-pack battery corner anti-lithium swelling tape includes a substrate, which is a swelling layer that can absorb the swelling of battery electrolyte and is sticky to the negative electrode slurry. One side of the swelling layer is compounded with an adhesive layer, and the other side of the swelling layer is compounded with a release film layer, thereby forming a composite swelling tape.

[0007] Further:

[0008] The composite swelling tape is a tape structure with holes arranged in a matrix.

[0009] The thickness of the swelling layer is 5 to 40 μm.

[0010] The thickness of the adhesive layer is 1 to 10 μm.

[0011] The interval between adjacent holes on the swelling tape is 0.8 to 2 mm.

[0012] The holes are circular and have a diameter of 0.8 to 1.5 mm.

[0013] The distance between the edge holes on the swelling tape and the edge of the tape is 4-6 mm.

[0014] Compared with the prior art, the present invention has the following advantages:

[0015] The soft pack battery corner anti-lithium swelling tape is reasonably designed. The swelling layer replaces the original diaphragm. After the swelling layer absorbs the electrolyte and swells, it has a little stickiness to the diaphragm and the negative electrode slurry. Since there is electrolyte inside the swelling layer after swelling, it does not affect the LI + The tape can pass through the battery, and the efficiency is little different from that of the diaphragm; by punching and other methods, the proportion of the tape layer can be reduced, and it can be quickly and completely dissolved in a small amount of electrolyte; it can solve the problem of lithium-ion batteries being fast-charged by applying this tape on the inner layer at the corner position, which can effectively reduce the speed of lithium ion transmission in the inner layer, solve the problem of lithium plating on the negative electrode at the side corner of the battery, and is reliably fixed. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The following is a brief description of the contents and symbols in the drawings of this specification:

[0017] Figure 1 This is a schematic diagram of the tape layer structure of the utility model.

[0018] Figure 2 This is a schematic diagram of the punching layout of the tape of this utility model.

[0019] In the picture:

[0020] 1. Adhesive layer, 2. Swelling layer, 3. Release film layer. DETAILED DESCRIPTION

[0021] The specific implementation of the present invention will be further explained in detail below through the description of embodiments with reference to the accompanying drawings.

[0022] like Figure 1 and Figure 2 As shown, the soft-pack battery corner anti-lithium swelling tape includes a substrate, which is a swelling layer 2 that can absorb the battery electrolyte and swell and is sticky to the negative electrode slurry. One side of the swelling layer is compounded with an adhesive layer 1, and the other side of the swelling layer is compounded with a release film layer 3, thereby forming a composite swelling tape.

[0023] The composite swelling tape is a tape structure with holes arranged in a matrix. After the swelling layer absorbs the electrolyte and swells, it has a little stickiness to the diaphragm and negative electrode slurry. Since there is electrolyte inside the swelling layer after swelling, it does not affect the LI + The passing efficiency is close to that of the diaphragm; the soft-pack battery corners have good anti-lithium deposition effect and are reliably fixed.

[0024] Preferably,

[0025] The thickness of the swelling layer is 5 to 40 μm; the thickness of the adhesive layer is 1 to 10 μm; the interval between adjacent holes on the swelling tape is 0.8 to 2 mm;

[0026] The holes are circular with a diameter of 0.8 to 1.5 mm; the distance between the edge holes on the swelling tape and the edge of the tape is 4 to 6 mm.

[0027] By punching holes and other methods, the proportion of the tape layer can be reduced, and it can be quickly and completely dissolved in a small amount of electrolyte; it can solve the problem of lithium-ion batteries being fast-charged by applying this tape on the inner layer at the corner position, which can effectively reduce the speed of lithium ion transmission in the inner layer, solve the problem of lithium plating on the negative electrode at the side corner of the battery, and fix it reliably.

[0028] A preferred specific example of the present invention is as follows: the swelling layer material is polytrimethylene carbonate and polybutylene succinate, with a thickness of 5 to 40 μm, the adhesive layer material is polyacrylate, polyvinyl acetate and polystyrene resin; the thickness is 1 to 10 μm, the adhesive is coated on a PET release film treated with a silicone release agent, and after curing and drying, an adhesive layer is obtained, the adhesive layer is die-cut and punched (the interval between adjacent holes is 0.8 to 2 mm, the hole structure is circular, the diameter is 0.8 to 1.5 mm, and the distance from the hole diameter to the edge of the tape is 5 mm), and then the adhesive layer is bonded to the battery separator to obtain a finished tape.

[0029] The adhesive layer is die-cut and punched, which can reduce the proportion of the tape's adhesive layer by about half without affecting the use of the tape. It can speed up the dissolution rate of the tape in the electrolyte and can dissolve quickly and completely even in the presence of very little electrolyte. It can solve the problem of lithium-ion batteries being fast-charged, and can also avoid the problem of bubbles being emitted during the use of the tape. Applying this tape on the inner layer at the corner position can effectively reduce the speed of lithium ion transmission in the inner layer, solving the problem of lithium plating on the negative electrode at the side corner of the battery.

[0030] The above is only an illustration of a preferred embodiment of the present invention. The above technical features can be arbitrarily combined to form multiple embodiments of the present invention.

[0031] The above is an exemplary description of the present invention in conjunction with the accompanying drawings. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned method. As long as various non-substantial improvements are made using the concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the scope of protection of the present invention.

Claims

1. A soft-pack battery corner anti-lithium swelling tape, comprising a substrate, characterized in that: The substrate is a swelling layer that can absorb battery electrolyte to swell and is sticky to the negative electrode slurry. One side of the swelling layer is compounded with an adhesive layer, and the other side of the swelling layer is compounded with a release film layer, thereby forming a composite swelling tape.

2. The soft-pack battery corner anti-lithium swelling tape according to claim 1, characterized in that: The composite swelling tape is a tape structure with holes arranged in a matrix.

3. The soft-pack battery corner anti-lithium swelling tape according to claim 1, characterized in that: The thickness of the swelling layer is 5 to 40 μm.

4. The soft-pack battery corner anti-lithium swelling tape according to claim 1, characterized in that: The thickness of the adhesive layer is 1 to 10 μm.

5. The soft-pack battery corner anti-lithium swelling tape according to claim 2, characterized in that: The interval between adjacent holes on the swelling tape is 0.8 to 2 mm.

6. The adhesive tape for preventing lithium swelling at corners of soft-pack batteries according to claim 5, characterized in that: The holes are circular and have a diameter of 0.8 to 1.5 mm.

7. The adhesive tape for preventing lithium swelling at corners of soft-pack batteries according to claim 6, characterized in that: The distance between the edge holes on the swelling tape and the edge of the tape is 4-6 mm.

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