A protection sheet, a top cover assembly and a single battery

Abstract

The application discloses a protection sheet, a top cover assembly and a single battery. The protection sheet is used for being bonded on a top cover of the single battery to cover a blast hole. The protection sheet comprises a protection part, a connecting part and a hydrophobic coating. The connecting part is annularly arranged on the protection part and is used for being bonded on the top cover. The protection part is used for covering the blast hole. The protection part is provided with a through groove for air permeation. The through groove does not allow electrolyte to permeate. The hydrophobic coating is coated on the protection part and surrounds the through groove. The protection sheet can ensure air circulation and isolate electrolyte.

Description

Technical Field

[0001] This invention relates to the technical field of protective sheets, and more particularly to a protective sheet, a top cover assembly, and a single battery cell. Background Technology

[0002] With the booming development of the new energy industry and the further popularization of new energy electric vehicles, the demand for electric vehicles is increasing. Power cell manufacturers are becoming more and more stringent in their requirements for the safety performance of power cells, especially in whether the cells fail prematurely during a short circuit, i.e., the explosion-proof valve bursts. However, the current traditional cell design has a risk of exposing the explosion-proof valve to the atmospheric environment.

[0003] Currently, in lithium-ion power battery structures, an explosion-proof valve is welded to the lower end of the top cover to prevent explosions caused by short circuits in the battery cells. To address the risk of electrolyte accidentally entering the explosion-proof valve during cell manufacturing, causing short-term or long-term corrosion and premature explosion, thus reducing battery life, traditional top cover designs involve directly attaching a PET patch with double-sided adhesive to the top cover at the explosion-proof valve location. However, during actual cell manufacturing, leakage or failures during electrolyte injection can easily dissolve the double-sided adhesive, causing the protective PET patch to fail and enter the explosion-proof valve, corroding it and reducing cell lifespan. Furthermore, the airtightness testing process during manufacturing may cause the adhesive PET patch to misalign, losing its protective function against the explosion-proof valve. Over time, the explosion-proof valve corrodes, reducing the cell's withstand voltage failure capability and leading to premature cell failure, further reducing its lifespan. Additionally, during cell airtightness testing, it's possible for the cell to pass the airtightness test, but the explosion-proof valve itself may have a poor airtightness.

[0004] Therefore, there is an urgent need to develop a protective sheet to prevent electrolyte from entering the explosion-proof valve after leakage or failure during injection. On the other hand, the formed container has a certain pressure relief capacity to prevent the PET patch with adhesive from being misaligned during the airtightness inspection, which would cause the explosion-proof valve to lose its original burst value capability and improve the service life of the battery cell. Summary of the Invention

[0005] The purpose of this invention is to provide a top cover assembly and a single battery cell to solve the technical problem of leakage of the protective sheet.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a protective sheet is provided, which is used to adhere to the top cover of a single battery cell to cover the explosion-proof hole. The protective sheet includes: a protective part, a connecting part, and a hydrophobic coating. The connecting part is arranged around the protective part and is used to adhere to the top cover. The protective part is used to cover the explosion-proof hole. The protective part has a through groove for ventilation. The through groove does not allow electrolyte to pass through. The hydrophobic coating is applied to the protective part and surrounds the through groove.

[0007] Optionally, the protective part includes a first sub-part and a second sub-part, the first sub-part is connected to the connecting part, the second sub-part is connected to the first sub-part and protrudes outward, and a through groove is formed on the second sub-part.

[0008] Optionally, there are multiple through slots and multiple second sub-parts, with at least one through slot provided on each second sub-part.

[0009] Optionally, there are multiple through slots and one second sub-part, with multiple through slots disposed on the second sub-part.

[0010] Optionally, there are multiple through slots that are parallel to each other, and the length direction of the through slots is perpendicular to the length direction of the protective part.

[0011] Optionally, the length of the through groove is 0.5 mm to 2 mm, and the width of the through groove is 0.02 mm to 0.1 mm.

[0012] To achieve the above objectives, the present invention adopts the following technical solution: a top cover assembly is provided, the top cover assembly including: a top cover, an explosion-proof valve and a protective plate of any one of the above, the top cover having an explosion-proof hole, the explosion-proof valve being connected to one side of the top cover and covering the explosion-proof hole, and the protective plate being connected to the opposite side of the top cover and covering the explosion-proof hole.

[0013] Optionally, the top cover ring has an explosion-proof hole with a stepped portion, and the protective sheet is adhered to the stepped portion.

[0014] Optionally, the stepped portion includes a first stepped portion and a second stepped portion stacked together, with the protective sheet adhered to the second stepped portion.

[0015] To achieve the above objectives, the present invention adopts the following technical solution: a single battery cell is provided, the single battery cell comprising: a battery cell, a housing, and a top cover assembly of any one of the above, the battery cell being assembled in the housing, and the top cover assembly sealing the housing.

[0016] The beneficial effects of this invention are as follows: The protective sheet includes a protective portion and a connecting portion surrounding the protective portion. The connecting portion is used to adhere to the top cover, and the protective portion is used to cover the explosion-proof hole. The protective portion has a through groove for ventilation, which prevents electrolyte from passing through. The protective sheet includes: a protective portion, a connecting portion, and a hydrophobic coating. The connecting portion surrounds the protective portion and is used to adhere to the top cover. The protective portion covers the explosion-proof hole, and the protective portion has a through groove for ventilation, which prevents electrolyte from passing through. The hydrophobic coating is applied to the protective portion and surrounds the through groove. The hydrophobic coating material can be petroleum jelly or an oil-based substance. When electrolyte flows to the surface of the protective sheet, the hydrophobic coating can quickly guide the electrolyte away, preventing the electrolyte from remaining on the surface of the protective sheet for too long and then entering the explosion-proof valve through the through groove and corroding the explosion-proof valve. Attached Figure Description

[0017] To more clearly illustrate the embodiments of the present invention or the technical solutions in the previous research and development, the drawings used in the description of the embodiments or the previous research and development will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0018] Figure 1 This is an exploded structural diagram of a single battery cell provided by the present invention;

[0019] Figure 2 This invention provides Figure 1 A three-dimensional cross-sectional diagram of region A in the middle;

[0020] Figure 3 This is a schematic diagram of the structure of the first embodiment of the protective sheet provided by the present invention;

[0021] Figure 4 This is a schematic diagram of the structure of the second embodiment of the protective sheet provided by the present invention;

[0022] Figure 5 This is a simulation diagram of the first embodiment of the protective sheet provided by the present invention;

[0023] Figure 6 This is a simulation diagram of the second embodiment of the protective sheet provided by the present invention;

[0024] Figure 7 This is a simulation diagram of the third embodiment of the protective sheet provided by the present invention;

[0025] Figure 8 This invention provides Figure 1 A schematic diagram of the planar cross-section of region A in the middle.

[0026] The diagram is marked as follows:

[0027] Single battery cell 100, battery cell 20, casing 30

[0028] Top cover assembly 10, Top cover 12, Explosion-proof hole 121

[0029] Step 123 First Step 124 Second Step 125

[0030] Explosion-proof valve 13, protective plate 11, protective unit 112

[0031] Through groove 115 Connector 114 Hydrophobic coating 116

[0032] First subsection 111 Second subsection 113 Detailed Implementation

[0033] In this invention, the use of terms such as "first," "second," etc., is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated.

[0034] Please see Figure 1 and Figure 2 , Figure 1 This is an exploded structural diagram of the single-cell battery 100 provided by the present invention. Figure 2 This invention provides Figure 1 A schematic diagram of the three-dimensional cross-section of region A in the middle.

[0035] The single-cell battery 100 of the present invention includes: a cell 20, a housing 30 and a top cover assembly 10. The cell 20 is an energy storage device and is assembled in the housing 30. The top cover assembly 10 covers the housing 30 and is electrically connected to the cell 20 to assist in the introduction of electrical energy into the cell 20 and the extraction of energy from the cell 20.

[0036] The top cover assembly 10 includes a top cover 12, an explosion-proof valve 13, and a protective plate 11. The top cover assembly 10 seals the housing 30. The top cover 12 has an explosion-proof hole 121. The explosion-proof valve 13 is connected to the side of the top cover 12 facing the cell 20 and covers the explosion-proof hole 121. The explosion-proof valve 13 is opened when the internal pressure of the housing 30 exceeds a preset value (e.g., 4 kg) to release pressure and prevent the single cell 100 from exploding. The protective plate 11 is connected to the opposite side of the top cover 12 and covers the explosion-proof hole 121. The protective plate 11 is used to prevent overflowing electrolyte from flowing through the outer surface of the top cover 12 to the explosion-proof valve 13 when electrolyte is injected into the housing 30, thus preventing contamination and chemical corrosion of the explosion-proof valve 13 and affecting its explosion-proof performance.

[0037] The explosion-proof hole 121 can be square, oval, racetrack-shaped, or similar in shape. Correspondingly, the protective plate 11 has a similar shape to the explosion-proof hole 121, and can also be square, oval, racetrack-shaped, or similar in shape.

[0038] The protective plate 11 includes a protective portion 112, a connecting portion 114, and a hydrophobic coating 116. The connecting portion 114 surrounds the protective portion 112 and is used to adhere to the top cover 12. The protective portion 112 covers the explosion-proof hole 121 and has a through groove 115 for ventilation, which prevents electrolyte from passing through. The hydrophobic coating 116 is applied to the protective portion 112 and surrounds the through groove 115. The hydrophobic coating 116 can be made of petroleum jelly or an oil-based substance. When electrolyte flows to the surface of the protective plate 11, the hydrophobic coating 116 can quickly guide the electrolyte away, preventing the electrolyte from remaining on the surface of the protective plate 11 for too long and then entering the explosion-proof valve 13 through the through groove 115 and corroding the explosion-proof valve 13. The hydrophobic coating 116 can completely cover the protective portion 112 or partially cover it.

[0039] The through-slot 115 can be trough-shaped rather than perforated. While maintaining the same permeability rate required for helium detection, the width of the through-slot 115 can be made smaller, thus ensuring that the electrolyte does not flow through the through-slot 115 to the explosion-proof valve 13. The through-slot 115 can be square, racetrack-shaped, etc.

[0040] Please see Figures 1 to 4 , Figure 3 This is a schematic diagram of the structure of the first embodiment of the protective sheet 11 provided by the present invention. Figure 4 This is a schematic diagram of the structure of the second embodiment of the protective sheet 11 provided by the present invention.

[0041] The protective portion 112 includes a first sub-portion 111 and a second sub-portion 113. The first sub-portion 111 is connected to the connecting portion, and the second sub-portion 113 is connected to the first sub-portion 111 and protrudes outward. A through groove 115 is formed on the second sub-portion 113, and the second sub-portion 113 forms a step relative to the first sub-portion 111, thereby preventing electrolyte from flowing into the through groove 115. In addition, the second sub-portion 113 protrudes relative to the first sub-portion 111, forming a rib, thereby enhancing the structural strength of the protective portion 112 and making it less prone to deformation.

[0042] like Figure 3 In the first embodiment, there are multiple through slots 115 and multiple second sub-parts 113, with at least one through slot 115 provided on each second sub-part 113. Each second sub-part 113 is independent of the others, and when one second sub-part 113 is deformed by compression, the other second sub-parts 113 will not deform.

[0043] Of course, such as Figure 4 In the second embodiment, there can be multiple through slots 115 and one second sub-part 113, with multiple through slots 115 disposed on the second sub-part 113.

[0044] Please see Figure 5 and Figure 6 , Figure 5 This is a simulation diagram of the first embodiment of the protective sheet 11 provided by the present invention. Figure 6 This is a simulation diagram of the second embodiment of the protective sheet 11 provided by the present invention.

[0045] In this embodiment, the difference from the above embodiments is that the number of through slots 115 is multiple and they are parallel to each other, for example, two (e.g., Figure 6 (e.g., three, four, etc.) Multiple through-slots 115 can facilitate venting. Under the condition that the venting rate required for helium detection is the same, the width of the through-slots 115 can be made smaller, thus further ensuring that the electrolyte does not flow through the through-slots 115 to the explosion-proof valve 13.

[0046] Figure 5 The information displayed is a simulation of the deformation of a protective plate 11 with only one through-slot 115 when a single cell undergoes helium testing at 0.25 MPa. The deformation amounts from the inner ring to the outer ring are 1.941 mm, 1.725 mm, 1.510 mm, 1.294 mm, 1.078 mm, 0.8626 mm, 0.647 mm, 0.4313 mm, and 0.2157 mm, respectively. The maximum deformation of the through-slot 115 is 0.121 mm.

[0047] Figure 6 The information displayed is a simulation of the deformation of a protective plate 11 with only two through slots 115 when a single cell undergoes helium testing at 0.25 MPa. The deformation amounts from the inner ring to the outer ring are 1.936 mm, 1.721 mm, 1.506 mm, 1.291 mm, 1.076 mm, 0.8605 mm, 0.6454 mm, 0.4302 mm, and 0.2151 mm, respectively. The maximum deformation of the through slot 115 is 0.119 mm.

[0048] Please see Figure 5 and Figure 7 , Figure 7 This is a simulation diagram of the third embodiment of the protective sheet 11 provided by the present invention.

[0049] In this embodiment, the difference from the above embodiments is that... Figure 5 The length direction of the through groove 115 is perpendicular to the length direction of the protective part 112. Figure 7 The length direction of the through groove 115 is parallel to the length direction of the protective part 112. (This is achieved through...) Figure 5 and Figure 7 A comparison shows that when the length direction of the through groove 115 is perpendicular to the length direction of the protective part 112, the width of the through groove 115 can be made smaller. It is worth noting that in this embodiment, the protective part 112 has mutually perpendicular length and width directions. In this technical field, it is generally assumed that the length direction is longer than the width direction; that is, in this embodiment, the protective part 112 is assumed to be elongated. The shape of the protective part 112 can be square, elliptical, racetrack-shaped, etc.

[0050] Figure 7 The information displayed is a simulation of the deformation of a protective plate 11 with only one through-slot 115 when a single cell undergoes helium testing at 0.25 MPa. The deformation amounts from the inner ring to the outer ring are 1.968 mm, 1.749 mm, 1.530 mm, 1.312 mm, 1.093 mm, 0.8745 mm, 0.6559 mm, 0.4372 mm, and 0.2186 mm, respectively. The maximum deformation of the through-slot 115 is 0.137 mm.

[0051] Optionally, the length of the through groove 115 is from 0.5 mm to 2 mm, for example, 0.5 mm, 0.8 mm, 1 mm, 0.5 mm, 2 mm, 0.5 mm, etc. This length range of the through groove 115 can ensure a smaller width of the through groove 115 without compromising the overall strength of the protective sheet 11.

[0052] Optionally, the width of the through groove 115 is 0.02 mm to 0.1 mm, for example, 0.02 mm, 0.04 mm, 0.05 mm, 0.06 mm, 0.08 mm, 0.1 mm, etc.

[0053] Furthermore, the normal bonding strength of the connecting part 114 is 360 kPa to 650 kPa, for example, 360 kPa, 400 kPa, 450 kPa, 500 kPa, 550 kPa, 650 kPa, etc., and the tangential bonding strength of the connecting part 114 is 280 kPa to 520 kPa, for example, 280 kPa, 300 kPa, 350 kPa, 400 kPa, 450 kPa, 520 kPa, etc. When the normal bonding strength and tangential bonding strength of the connecting part 114 meet the above requirements, the protective plate 11 of the explosion-proof valve 13 will be firmly bonded to the top cover 12 during helium detection, and will not separate from the top cover 12.

[0054] Please see Figure 1 and Figure 8 , Figure 8 This invention provides Figure 1 A schematic diagram of the planar cross-section of region A in the middle.

[0055] The top cover 12 is provided with explosion-proof holes 121 and a raised step portion 123. The step portion 123 is higher than the surface of the top cover 12. The step portion 123 can be formed by stamping, and the protective sheet 11 is bonded to the step portion 123. The step portion 123 can buffer the electrolyte, thereby preventing excessive electrolyte from contacting the protective sheet 11.

[0056] Specifically, the stepped portion 123 includes a first stepped portion 124 and a second stepped portion 125 stacked together. The second stepped portion 125 is located on the side of the first stepped portion 124 away from the battery cell 20, and the protective sheet 11 is adhered to the second stepped portion 125. The first stepped portion 124 and the second stepped portion 125 sequentially serve to buffer the electrolyte, thereby further preventing excessive electrolyte from contacting the protective sheet 11. Of course, in some embodiments, a third stepped portion 123, a fourth stepped portion 123, a fifth stepped portion 123, etc., may also be included.

[0057] Furthermore, the height of the first step portion 124 includes 0.1 mm to 3 mm, for example, 0.1 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 3 mm, etc. The height of the second step portion 125 includes 0.1 mm to 5 mm, for example, 0.1 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, etc.

[0058] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural transformations made using the contents of the specification and drawings of the present invention under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the scope of patent protection of the present invention.

Claims

1. A protection sheet for adhering to a top cover of a single battery to cover an explosion-proof hole, characterized in that, The protection sheet comprises a protection part, a connecting part and a hydrophobic coating, the connecting part is annularly arranged on the protection part, the connecting part is used for being bonded on the top cover, the protection part is used for covering the explosion-proof hole, the protection part is provided with a through slot for air permeation, the through slot does not allow electrolyte to permeate, the hydrophobic coating is coated on the protection part and surrounds the through slot, the length of the through slot is 0.5-2 mm, and the width of the through slot is 0.02-0.1 mm. The protection part comprises a first sub-part and a second sub-part, the first sub-part is connected with the connecting part, the second sub-part is connected with the first sub-part and protrudes outward, and the through slot is arranged on the second sub-part. The number of the through slots is multiple, the number of the second sub-parts is multiple, and at least one through slot is arranged on each second sub-part. The normal bonding strength of the connecting part is 360-650 KPa, and the tangential bonding strength of the connecting part is 280-520 KPa.

2. The protective sheet according to claim 1, characterized by The multiple through slots are parallel to each other, and the length direction of the through slot is perpendicular to the length direction of the protection part.

3. A cap assembly characterized by, The top cover assembly comprises a top cover, an explosion-proof valve and the protection sheet according to any one of claims 1-2, the top cover is provided with an explosion-proof hole, the explosion-proof valve is connected with one side of the top cover and covers the explosion-proof hole, and the protection sheet is connected with the opposite side of the top cover and covers the explosion-proof hole.

4. The roof assembly of claim 3, wherein, The top cover is annularly provided with a stepped part around the explosion-proof hole, and the protection sheet is bonded on the stepped part.

5. The roof assembly of claim 4, wherein, The stepped part comprises a first stepped part and a second stepped part which are stacked, and the protection sheet is bonded on the second stepped part.

6. A single cell characterized by, The single battery comprises an electric core, a shell and the top cover assembly according to any one of claims 3-5, the electric core is assembled in the shell, and the top cover assembly covers the shell.

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