A lithium battery with stable structural support

Abstract

The utility model discloses a lithium battery with stable structural support, including a support belt and a battery cell, wherein the outer side of the battery cell is surrounded by a support belt connected end to end, and the inner side of the support belt is sequentially provided with a plurality of filling protrusions along the circumference from top to bottom, and the filling protrusions are inserted into the gap between the negative electrode and the positive electrode of the battery cell; the filling protrusions include a filling body and a buffer layer, and the outer side of the filling body is coated with a buffer layer. The utility model fills the gap between the positive electrode and the negative electrode of the all-solid-state battery through the filling protrusions, and the support belt installed at the edge of the battery cell can prevent the pole piece from being dislocated under high pressure during the final molding of the all-solid-state battery, and the support belt improves the overall force stability, effectively solving the problem of fracture and collapse of the negative electrode and electrolyte membrane inside the battery cell, while also improving the assembly efficiency, and has good practicality.

Description

Technical Field

[0001] The utility model belongs to the technical field of all-solid-state lithium batteries, and in particular relates to a lithium battery with a stable structural support. Background Art

[0002] When designing lithium-ion batteries, the size of the separator is larger than that of the negative electrode and the positive electrode to prevent contact between the negative electrode and the positive electrode, and the size of the negative electrode is slightly larger than that of the positive electrode to effectively solve the short circuit problem caused by lithium precipitation at the edge of the negative electrode. Sulfide all-solid-state lithium batteries use a solid electrolyte membrane as a transmission medium for lithium ions. The positive electrode, negative electrode and electrolyte membrane need to be in close contact to provide a better transmission path for lithium ions. When designing sulfide all-solid-state batteries, in order to increase energy, the battery is usually composed of multiple layers of positive electrodes, negative electrodes and electrolyte membranes. The electrolyte membrane and the negative electrode are the same size, and the negative electrode can provide support for the electrolyte membrane; the size of the negative electrode is slightly larger than the positive electrode to prevent lithium precipitation at the edge of the negative electrode and cause a short circuit.

[0003] However, the existing sulfide all-solid-state battery structure has a gap between the positive and negative electrodes, which can easily cause the edges of the negative electrode and electrolyte membrane to break, collapse, and break during the later battery pressure molding process, causing battery deformation, short circuit, and other problems. At the same time, due to the pressure during the later high-pressure molding process of the sulfide all-solid-state battery, the positive and negative electrodes between the layers will be misaligned, resulting in uneven battery edges and even safety issues such as contact between the positive and negative electrodes.

[0004] In the prior art, the edge problem of sulfide all-solid-state batteries is often improved by coating a gel material with insulating and supporting functions between the positive and negative electrodes. However, in the actual implementation process, each layer needs to be coated, which is inefficient and fails to solve the problem of misalignment between pole pieces under high voltage. In addition, the prior art solution of reducing stress concentration around the stress dispersion layer in the positive electrode material layer to cause edge fracture and collapse is inefficient and cannot improve the misalignment problem. Therefore, there is an urgent need for a solution that can effectively solve the edge fracture, collapse and pole piece misalignment of sulfide batteries. Utility Model Content

[0005] The utility model aims to provide a lithium battery with stable structural support, aiming to solve the above-mentioned problems.

[0006] The utility model is mainly realized through the following technical solutions:

[0007] A lithium battery with stable structural support comprises a support belt and a battery cell, wherein the outer side of the battery cell is surrounded by a support belt connected end to end, and the inner side of the support belt is provided with a plurality of filling protrusions along the circumference from top to bottom, and the filling protrusions are inserted into the gap between the negative electrode and the positive electrode of the battery cell; the filling protrusions comprise a filling body and a buffer layer, and the outer side of the filling body is coated with the buffer layer.

[0008] In order to better realize the present utility model, further, the length L1 of the support band is greater than the outer circumference of the battery cell by 0.1~30mm, the total length L2 of the filling protrusions at the same height is greater than the outer circumference of the battery cell by 0.1~20mm, and the difference between the length L1 of the support band and the total length L2 of the filling protrusions at the same height is 0.1~10mm.

[0009] In order to better realize the utility model, further, the thickness of the filling protrusion is 0.008-12 mm, and the height is 0.1-15 mm; the spacing between adjacent filling protrusions is 0.008-8 mm.

[0010] In order to better realize the utility model, further, the thickness of the filling body is 0.005~6mm, and the protrusion height is 0.1~8mm; the single-side thickness of the buffer layer is 0.001~6mm, the height is 0.1~8mm, the top thickness is 0.001~6mm, and the top width W1 is 0.005~6mm.

[0011] In order to better realize the utility model, further, the upper end of the cross section of the filling protrusion is a trapezoidal structure, and the trapezoidal corner α of the buffer layer is 5°<α<80°, and the top thickness is 0.005~2mm.

[0012] In order to better realize the utility model, further, the R angle size at the corner of the support belt is 0.01~50mm, the R angle size at the corner of the filling protrusion is 0.1~1mm, and the R angle size of the buffer layer is 0.01~25mm.

[0013] In order to better realize the utility model, further, the corner β of the starting end of the support belt is 45°±15°; the thickness T of the support belt is 0.1~10mm, and the width is 0.4~4000mm; the width of the support belt is smaller than the thickness of the battery cell by 0.01~3mm.

[0014] In order to better realize the utility model, further, the support belt is made of any one or more materials selected from polyethylene, polyvinyl chloride, polypropylene, polytetrafluoroethylene, and polyvinylidene fluoride.

[0015] In order to better realize the utility model, further, the filling body is made of any one or more materials selected from polyvinyl chloride, polyvinylidene fluoride, polytetrafluoroethylene, polyperfluoroethylene propylene, and polyethylene terephthalate.

[0016] In order to better realize the utility model, further, the buffer layer is prepared from any one or more materials of styrene-butadiene rubber, butadiene rubber, vulcanized rubber, polyvinyl chloride, nitrile-butadiene rubber, thermoplastic polyurethane elastomer rubber, chlorinated butyl rubber, brominated butyl rubber, acrylate rubber, and epichlorohydrin rubber.

[0017] The beneficial effects of the utility model are as follows:

[0018] The utility model fills the gap between the positive electrode and the negative electrode of the all-solid-state battery by means of the filling protrusions. The support belt installed at the edge of the battery cell can prevent the pole pieces of the all-solid-state battery from being dislocated under high-pressure pressing during the final molding. The support belt improves the overall force stability, effectively solves the problem of fracture and collapse of the negative electrode and the electrolyte membrane inside the battery cell, and also improves the assembly efficiency, which has good practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the connection structure between the support belt and the finishing tape;

[0020] Figure 2 It is a schematic diagram of the connection structure between the support belt and the battery cell;

[0021] Figure 3 It is a schematic diagram of the connection structure between the support belt and the filling protrusion;

[0022] Figure 4 Schematic diagram of the trapezoidal corner α of the buffer layer;

[0023] Figure 5 Schematic diagram of the corner β at the starting end of the support belt.

[0024] Among them: 1-support tape, 2-battery core, 3-filling protrusion, 4-filling body, 5-buffer layer, 6-finishing tape, 7-high temperature tape. DETAILED DESCRIPTION

[0025] Embodiment 1:

[0026] A lithium battery with a stable structural support, including a support belt 1 and a battery cell 2, is used to efficiently solve the problem of edge fracture and collapse of sulfide batteries and pole piece misalignment during high-pressure forming, quickly fill the gap between the positive electrode and the negative electrode, and greatly reduce the misalignment between the pole pieces. Figure 1-Figure 3As shown, a support belt 1 connected end to end is installed on the outer side of the battery cell 2, and a plurality of filling protrusions 3 are arranged in sequence from top to bottom along the circumference of the inner side of the support belt 1, and the filling protrusions 3 are inserted into the gap between the positive electrode and the negative electrode, so that the support belt 1 surrounds the battery cell 2 and the filling protrusions 3 are inserted into the gap, and the support belt 1 is connected end to end.

[0027] Preferably, if Figure 1 As shown, the end of the support belt 1 is fixed with a tail tape 6, and a plurality of high-temperature tapes 7 are arranged along the circumference between the support belt 1 and the battery cell 2. Further, the tail tape 6 includes but is not limited to: Teflon tape, release paper laminating tape, BOPP polypropylene tape, PVC base tape, high-temperature insulating polyimide tape, and high-temperature resistant PET tape. Further, the high-temperature tape 7 includes but is not limited to: Teflon tape, release paper laminating tape, BOPP polypropylene tape, PVC base tape, high-temperature insulating polyimide tape, and high-temperature resistant PET tape.

[0028] Preferably, the support belt 1 is bonded to the filling protrusion 3 to form a whole, the filling protrusion 3 includes a filling body 4 and a buffer layer 5 , and the buffer layer 5 is arranged on the outer side of the filling body 4 .

[0029] Preferably, the filling body 4 is made of any one or more materials selected from the group consisting of polyvinyl chloride, polyvinylidene fluoride, polytetrafluoroethylene, polyperfluoroethylene propylene, and polyethylene terephthalate.

[0030] Preferably, the buffer layer 5 is made of any one or more of styrene-butadiene rubber, butadiene rubber, vulcanized rubber, polyvinyl chloride, nitrile-butadiene rubber, thermoplastic polyurethane elastomer rubber, chlorinated butyl rubber, brominated butyl rubber, acrylate rubber, and epichlorohydrin rubber.

[0031] Preferably, the support belt 1 is made of any one or more materials selected from the group consisting of polyethylene, polyvinyl chloride, polypropylene, polytetrafluoroethylene, and polyvinylidene fluoride.

[0032] Preferably, the length of the filling protrusion 3 is 0.1-20 mm greater than the outer circumference of the battery core 2; the length of the supporting belt 1 is 0.1-30 mm greater than the outer circumference of the battery core 2; Figure 5 As shown, the length of the support belt 1 is 0.1-10 mm greater than the length of the filling protrusion 3. Preferably, the thickness of the filling protrusion 3 is 0.008-12 mm; the height of the filling protrusion 3 is 0.1-15 mm; the spacing of the filling protrusion 3 is 0.008-8 mm. Preferably, the R angle control range of the filling protrusion 3 is 0.1-1 mm.

[0033] Preferably, the thickness of the filling body 4 is in the range of 0.005-6 mm; the height of the filling body 4 is in the range of 0.1-8 mm; the thickness of the buffer layer 5 on one side is 0.001-6 mm. Preferably, the buffer layer 5 wraps the filling body 4 with a thickness of 0.001-6 mm;

[0034] Preferably, the thickness of the top of the buffer layer 5 is 0.001-6 mm; the width of the top of the buffer layer 5 is 0.005-6 mm;

[0035] Preferably, the buffer layer 5 has a height of 0.1 to 8 mm and a top thickness of 0.005 to 2 mm. Figure 4 As shown, the trapezoidal corner angle α of the buffer layer 5 is in the range of 80°>α>5°. Preferably, the R angle of the buffer layer 5 is controlled in the range of 0.01-25 mm.

[0036] Preferably, if Figure 5 As shown, the angle β of the starting section of the support belt 1 ranges from 45°±15°. Preferably, the R angle of the support belt 1 is controlled in the range of 0.01~50mm. Preferably, the thickness of the support belt 1 is 0.1~10mm; the width of the support belt 1 is 0.4~4000mm; the width of the support belt 1 is less than the thickness of the battery cell 2 by 0.01~3mm.

[0037] Preferably, the pressing is performed by isostatic pressing, the pressure required for isostatic pressing of the battery cell 2 is 5Mpa-1000Mpa, the pressing temperature is 20-120° C., and the holding time is 5min-60min.

[0038] Embodiment 2:

[0039] A lithium battery with stable structural support, the preparation method comprising the following steps:

[0040] 1) Stacking of the electrode sheets of the battery cell 2: stack the support sheet, the composite negative electrode with the negative electrode and the electrolyte, and the positive electrode in order, then stack the composite negative electrode and the positive electrode once, stack 6 negative electrode sheets and 5 positive electrode sheets, and finally stack the support sheet;

[0041] 2) Assembling the support tape 1 and the filling protrusion 3: inserting the structure formed by combining the filling protrusion 3 and the support tape 1 into the gap between the positive electrode and the negative electrode of the battery cell 2 stacked in step 1) with one corner first;

[0042] 3) The support tape 1 surrounds the battery cell 2 and inserts the filling protrusion 3 into the battery cell 2: the filling protrusion 3 is inserted into the gap between the positive electrode and the negative electrode of the battery cell 2 along the gap to form a structure surrounding the battery cell 2;

[0043] 4) The support tape 1 and the filling protrusion 3 are assembled: the filling protrusion 3 and the support tape 1 are wrapped around the battery cell 2 prepared in step 1) and the end portion is inserted, and the end portion is fixed with a finishing glue to form a structure connected end to end, and the support tape 1 is fixed on the four sides of the battery cell 2 with a high-temperature tape 7;

[0044] 5) Battery packaging: welding the tabs of the battery cell 2 prepared in step 4) and packaging them with an aluminum-plastic bag, and forming them by cold isostatic pressing;

[0045] 6) Battery test: Use a multimeter to test the molding voltage of the molded battery prepared in step 5) to check whether the battery is short-circuited. Perform a charge and discharge cycle at 2.5~4.3V at 0.05C current in a 25℃ environment to test whether the battery can be charged and discharged normally. If the voltage is lower than 0.05V or cannot be charged and discharged normally, it means that the battery is short-circuited.

[0046] As shown in Table 1, 10 samples were prepared in parallel in this example.

[0047] Comparative Example 1: The difference between Comparative Example 1 and the present embodiment is that step 2) to step 4) in the present embodiment are cancelled, that is, Comparative Example 1 is carried out in the order of step 1), step 5), and step 6) in the present embodiment. Similarly, 10 samples are prepared in parallel in Comparative Example 1.

[0048] Comparative Example 2: The specific steps of preparation are as follows:

[0049] 1) Stacking of the electrode sheets of the battery cell 2: stack the support sheet, the composite negative electrode with the negative electrode and the electrolyte, and the positive electrode in order, evenly fill the glue material on the negative electrode with the extra positive electrode size, and then stack the composite negative electrode and positive electrode after it is completely dry, and repeat the stacking to stack 6 negative electrode sheets and 5 positive electrode sheets, and finally finish with the support sheet;

[0050] 2) Battery packaging: welding the tabs of the battery cell 2 prepared in step 1) and packaging them with an aluminum-plastic bag, and forming them by cold isostatic pressing;

[0051] 3) Battery test: Use a multimeter to test the molding voltage of the molded battery prepared in step 2) to check whether the battery is short-circuited. Perform a charge and discharge cycle at 25°C with a current of 0.05C at 2.5~4.3V to test whether the battery can be charged and discharged normally. If the voltage is lower than 0.05V or cannot be charged and discharged normally, it means that the battery is short-circuited.

[0052] Similarly, 10 samples were prepared in parallel in Comparative Example 2.

[0053] As shown in Table 1, by comparison, it is found that in this embodiment, the support belt 1 and the filling protrusion 3 are assembled into the battery core 2, the short-circuit rate of the sulfide all-solid-state battery molding is significantly reduced, and the battery quality is effectively improved, which proves that the utility model can effectively improve the problems of edge fracture, collapse and dislocation of the battery during the high-pressure molding process.

[0054] Table 1

[0055]

[0056] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A lithium battery with stable structural support, characterized in that: The invention comprises a support belt (1) and a battery cell (2), wherein the outer side of the battery cell (2) is surrounded by a support belt (1) connected end to end, and the inner side of the support belt (1) is provided with a plurality of filling protrusions (3) in sequence from top to bottom along the circumference, and the filling protrusions (3) are inserted into the gap between the negative electrode and the positive electrode of the battery cell (2); the filling protrusions (3) comprise a filling body (4) and a buffer layer (5), and the outer side of the filling body (4) is covered with the buffer layer (5).

2. A lithium battery with stable structural support according to claim 1, characterized in that: The length L1 of the support band (1) is 0.1-30 mm greater than the outer circumference of the battery cell (2), the total length L2 of the filling protrusions (3) at the same height is 0.1-20 mm greater than the outer circumference of the battery cell (2), and the difference between the length L1 of the support band (1) and the total length L2 of the filling protrusions (3) at the same height is 0.1-10 mm.

3. A lithium battery with stable structural support according to claim 1, characterized in that: The filling protrusions (3) have a thickness of 0.008 to 12 mm and a height of 0.1 to 15 mm; the spacing between adjacent filling protrusions (3) is 0.008 to 8 mm.

4. A lithium battery with stable structural support according to any one of claims 1 to 3, characterized in that: The thickness of the filling body (4) is 0.005-6 mm, and the height of the protrusion is 0.1-8 mm; the thickness of a single side of the buffer layer (5) is 0.001-6 mm, the height is 0.1-8 mm, the top thickness is 0.001-6 mm, and the top width W1 is 0.005-6 mm.

5. A lithium battery with stable structural support according to claim 4, characterized in that: The upper end of the cross section of the filling protrusion (3) is a trapezoidal structure, the trapezoidal corner angle α of the buffer layer (5) is 5°<α<80°, and the top thickness is 0.005-2 mm.

6. A lithium battery with stable structural support according to claim 1, characterized in that: The R angle size at the corner of the support belt (1) is 0.01-50 mm, the R angle size at the corner of the filling protrusion (3) is 0.1-1 mm, and the R angle size of the buffer layer (5) is 0.01-25 mm.

7. A lithium battery with stable structural support according to claim 1 or 6, characterized in that: The corner β of the starting end of the support belt (1) is 45°±15°; the thickness T of the support belt (1) is 0.1-10 mm, and the width is 0.4-4000 mm; the width of the support belt (1) is 0.01-3 mm less than the thickness of the battery cell (2).

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