Lithium metal solid-state battery carbon fiber multi-grid box body and forming method and application thereof

Abstract

The invention discloses a lithium metal solid-state battery carbon fiber multi-grid box body and a forming method and application thereof. The forming method of the carbon fiber multi-grid box body of the multi-module lithium metal solid-state battery comprises the following steps: (1) paving a first prepreg on the surface of a die cavity of a female die; (2) a split mold is provided, five faces of the split mold are covered with second prepregs, then the split mold is tightly pressed in the mold cavity covered with the first prepregs, the face, not covered with the second prepregs, of the split mold is made to be back to the bottom of the mold cavity, and a buffer layer is attached to the side face, not in direct contact with the female mold, of the split mold; (3) repeating the step (2) for more than one time to form a multi-grid structure; and (4) curing the first prepreg, the second prepreg and the buffer layer to form the multi-grid box body with a plurality of grid units. The process flow is simple, and the obtained multi-grid box body has relatively high structural strength and rigidity and can effectively bear pressure generated when the lithium metal solid-state battery expands and deforms.

Description

Technical Field

[0001] The present invention particularly relates to a lithium metal solid-state battery carbon fiber multi-grid box body and a forming method and application thereof, belonging to the technical field of battery boxes. Background Art

[0002] The volume of lithium metal solid-state batteries will expand and contract significantly during the charging and discharging process. The expansion and contraction of modules formed by stacking multiple lithium metal batteries is more obvious. Therefore, in a solid-state battery box containing multiple modules, a partition with buffer material is required between each module to give the lithium metal solid-state battery sufficient deformation margin. Carbon fiber battery boxes have high structural strength and rigidity, and can effectively bear the pressure generated by the expansion and deformation of lithium metal solid-state batteries. Summary of the invention

[0003] The main purpose of the present invention is to provide a lithium metal solid-state battery carbon fiber multi-grid box and a forming method and application thereof, so as to overcome the deficiencies in the prior art.

[0004] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention includes: A first aspect of an embodiment of the present invention provides a method for forming a multi-module lithium metal solid-state battery carbon fiber multi-grid box, which comprises: (1) Laying a first prepreg on the surface of a cavity of a concave mold, wherein the cavity of the concave mold is a rectangular parallelepiped structure; (2) Providing a split mold, the split mold being a rectangular parallelepiped structure, covering the second prepreg on five surfaces of the split mold, and then pressing it tightly into the mold cavity covered with the first prepreg, with the surface of the split mold not covered with the second prepreg facing away from the bottom of the mold cavity, and covering the side of the split mold that is not in direct contact with the concave mold with a buffer layer; (3) repeating step (2) one or more times to form a preform having a multi-grid structure; (4) The preform is cured to form a multi-grid box having a plurality of grid units, wherein the first prepreg is cured to form an outer shell of the multi-grid box, and the second prepreg and the buffer layer are cured to form a partition, wherein the plurality of grid units are separated by the partition, and the partition comprises a surface layer formed by the second prepreg and a buffer layer sandwiched between the surface layers.

[0005] The second aspect of the embodiment of the present invention provides a multi-module lithium metal solid-state battery carbon fiber multi-grid box manufactured by the forming method of the multi-module lithium metal solid-state battery carbon fiber multi-grid box.

[0006] A third aspect of an embodiment of the present invention is a lithium metal solid-state battery assembly, comprising: the multi-module lithium metal solid-state battery carbon fiber multi-grid box, and a lithium metal solid-state battery module, wherein the multiple lithium metal solid-state batteries contained in the lithium metal solid-state battery module are respectively arranged in multiple grid units of the multi-module lithium metal solid-state battery carbon fiber multi-grid box.

[0007] Compared with the prior art, the advantages of the present invention include: a method for forming a multi-module lithium metal solid-state battery carbon fiber multi-grid box body provided by an embodiment of the present invention has a simple process flow, and the obtained multi-grid box body has high structural strength and rigidity, and can effectively bear the pressure generated when the lithium metal solid-state battery expands and deforms. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a schematic structural diagram of a concave mold provided in a typical implementation case of the present invention; Figure 2 It is a schematic diagram of the configuration structure of the split mold and the buffer layer in a typical implementation case of the present invention; Figure 3 It is a schematic diagram of the structure after all the separate molds and the concave mold are configured in a typical implementation case of the present invention; Figure 4 It is a structural schematic diagram of a multi-module lithium metal solid-state battery carbon fiber multi-grid box obtained in a typical implementation case of the present invention. DETAILED DESCRIPTION

[0009] In view of the deficiencies in the prior art, the inventor of this case has proposed the technical solution of the present invention after long-term research and extensive practice. The technical solution, its implementation process and principle will be further explained as follows.

[0010] A first aspect of an embodiment of the present invention provides a method for forming a multi-module lithium metal solid-state battery carbon fiber multi-grid box, which comprises: (1) Laying a first prepreg on the surface of a cavity of a concave mold, wherein the cavity of the concave mold is a rectangular parallelepiped structure; (2) Providing a split mold, the split mold being a rectangular parallelepiped structure, covering the second prepreg on five surfaces of the split mold, and then pressing it tightly into the mold cavity covered with the first prepreg, with the surface of the split mold not covered with the second prepreg facing away from the bottom of the mold cavity, and covering the side of the split mold that is not in direct contact with the concave mold with a buffer layer; (3) repeating step (2) one or more times to form a preform having a multi-grid structure; (4) The preform is cured to form a multi-grid box having a plurality of grid units, wherein the first prepreg is cured to form an outer shell of the multi-grid box, and the second prepreg and the buffer layer are cured to form a partition, wherein the plurality of grid units are separated by the partition, and the partition comprises a surface layer formed by the second prepreg and a buffer layer sandwiched between the surface layers.

[0011] Furthermore, the first prepreg and the second prepreg are both carbon fiber prepregs.

[0012] Furthermore, the fiber volume content of the carbon fiber prepreg is 50%-70%, preferably 60%-65%.

[0013] Furthermore, the higher the fiber volume content in the carbon fiber prepreg, the higher the tensile strength, compressive strength and stiffness of the composite material. However, too high a fiber volume content (such as > 70%) may lead to uneven resin distribution, reduce interlayer bonding, and cause delamination or brittle fracture. At the same time, if the fiber volume content is higher and the resin content is lower, the resin fluidity may be insufficient, making it difficult to completely infiltrate the fiber, forming pores or resin-poor areas. For example, when FVC is > 65%, high pressure needs to be applied through the autoclave process to ensure uniform distribution of the resin. In addition, when the resin content is too low, the viscosity of the prepreg will be reduced, affecting the fit during layering, especially in complex curved molds, which are prone to warping or delamination.

[0014] Furthermore, the resin matrix contained in the carbon fiber prepreg includes at least one of epoxy resin, phenolic resin and polyimide.

[0015] Furthermore, the number of covering layers of the first prepreg is 13 layers, wherein the directions of the carbon fibers in the surface layers on both sides are in the 0° direction and the 90° direction, the direction of the carbon fibers in the middle layer is in the unidirectional 90° direction, and the direction of the carbon fibers in the remaining layers is in the unidirectional 0° direction. It can be understood that, in the thirteen layers of the first prepreg, the directions of the carbon fibers in the first layer and the tenth layer are in the 0° direction and the 90° direction, the direction of the carbon fibers in the seventh layer is in the unidirectional 90° direction, and the direction of the carbon fibers in the remaining layers is in the unidirectional 0° direction, and the carbon fibers in the first prepreg located in the surface layers on both sides are vertically crossed to form a woven layer.

[0016] Furthermore, the number of covering layers of the second prepreg is 8 layers, wherein the directions of the carbon fibers in the surface layers on both sides are in the 0° direction and the 90° direction, the direction of the carbon fibers in the middle layer is in the unidirectional 90° direction, and the direction of the carbon fibers in the remaining layers is in the unidirectional 0° direction. It can be understood that, in the eight layers of the second prepreg, the directions of the carbon fibers in the first and eighth layers are in the 0° direction and the 90° direction, the directions of the carbon fibers in the fourth and fifth layers are in the unidirectional 90° direction, and the directions of the carbon fibers in the remaining layers are in the unidirectional 0° direction. The carbon fibers in the second prepreg located in the surface layers on both sides are vertically crossed to form a woven layer.

[0017] Furthermore, the buffer layer is mainly composed of elastic material.

[0018] Furthermore, the elastic material includes foam formed by at least one of silicone, polyurethane elastomer, and rubber, or the elastic material is PMI foam.

[0019] Furthermore, the thickness ratio of the surface layer to the buffer layer in the separator is 1:3.

[0020] Furthermore, the thickness of each surface layer is 1 mm, and the thickness of the buffer layer is 3 mm.

[0021] Furthermore, the curing treatment comprises: packaging the preform obtained in step (3) with a vacuum bag and placing it in an autoclave, maintaining it at a temperature of 80° C. and a pressure of 3 MPa for 30 minutes, then raising the temperature to 125° C. and the pressure to 5 MPa, and maintaining them for 90 minutes, and finally lowering the temperature to 50° C. and releasing the pressure to normal pressure, thereby completing the curing.

[0022] Furthermore, the forming method of the multi-module lithium metal solid-state battery carbon fiber multi-grid box also includes: demolding after curing treatment and surface treatment of the obtained multi-grid box to remove excess hair and burrs, and process the required positioning holes.

[0023] The second aspect of the embodiment of the present invention provides a multi-module lithium metal solid-state battery carbon fiber multi-grid box manufactured by the forming method of the multi-module lithium metal solid-state battery carbon fiber multi-grid box.

[0024] Furthermore, the overall warping degree of the carbon fiber multi-grid box of the multi-module lithium metal solid-state battery is within 2 mm.

[0025] A third aspect of an embodiment of the present invention is a lithium metal solid-state battery assembly, comprising: the multi-module lithium metal solid-state battery carbon fiber multi-grid box, and a lithium metal solid-state battery module, wherein the multiple lithium metal solid-state batteries contained in the lithium metal solid-state battery module are respectively arranged in multiple grid units of the multi-module lithium metal solid-state battery carbon fiber multi-grid box.

[0026] Furthermore, during the charge and discharge cycle of the lithium metal solid-state battery module, the deformation of the lithium metal solid-state battery module in the thickness direction does not exceed 10% of the total thickness of the battery cell.

[0027] The technical solution, its implementation process and principle will be further explained below in conjunction with the accompanying drawings and specific implementation cases.

[0028] In a typical implementation case, a method for forming a multi-module lithium metal solid-state battery carbon fiber multi-grid box includes the following steps: 1) Lay several layers of prepreg in the large rectangular cavity as the shell.

[0029] Provide as Figure 1 The rectangular die shown in the figure has a cavity with a top opening, and the cavity is a rectangular structure. Thirteen layers of first prepreg are covered on the cavity surface of the die. The first prepreg is a carbon fiber prepreg with a fiber volume content of 50%-70%, preferably 60%-65%. Among the thirteen layers of first prepreg, the directions of the carbon fibers in the first and tenth layers are 0° and 90°, the direction of the carbon fibers in the seventh layer is unidirectional at 90°, and the direction of the carbon fibers in the remaining layers is unidirectional at 0°.

[0030] (2) Providing a split mold, wherein the split mold is a rectangular parallelepiped structure, a demoulding handle is provided on one surface of the split mold, and eight layers of second prepreg are laid on the five surfaces of the split mold except the surface with the demoulding handle, wherein the second prepreg is a carbon fiber prepreg having a fiber volume content of 50%-70%, preferably 60%-65%, wherein the directions of the carbon fibers in the first layer and the eighth layer are 0° and 90°, the directions of the carbon fibers in the fourth layer and the fifth layer are unidirectional 90°, and the directions of the carbon fibers in the remaining layers are unidirectional 0°; Then, it is pressed tightly into the mold cavity covered with the first prepreg, and the surface of the split mold not covered with the second prepreg faces away from the bottom of the mold cavity and upwards, and a buffer layer is attached to the side of the split mold that is not in direct contact with the concave mold. The buffer layer is a 3mm thick PMI foam, such as Figure 2 shown.

[0031] (3) Repeat step (2) five times until the last split mold is placed in the mold cavity to form a preform with a multi-grid structure, such as Figure 3 shown.

[0032] (4) The preform obtained in step (3) is packaged with a vacuum bag and placed in an autoclave for curing treatment. The curing treatment includes: setting the temperature in the autoclave to 80°C and the pressure to 3MPa, and maintaining for 30 minutes. Then, the temperature in the autoclave is increased to 125°C and the pressure is increased to 5MPa, and maintained for 90 minutes. Finally, the temperature in the autoclave is reduced to 50°C and the pressure is released to normal pressure, thereby completing the curing. A multi-grid box with a stable structure and sufficient deformation margin and multiple grid units can be obtained, such as Figure 4 As shown, the first prepreg forms the outer shell of a multi-grid box after being cured, the second prepreg and the buffer layer form a partition after being cured, a plurality of the grid units are separated by the partition, and the partition includes a surface layer formed by the second prepreg and a buffer layer sandwiched between the surface layers.

[0033] Theoretical and practical tests have shown that when lithium metal cells are encapsulated in the multi-module lithium metal solid-state battery carbon fiber multi-grid box, the number of cycles of the lithium metal cells under pressure is significantly better than that under no-pressure conditions. Through the optimization of the above-mentioned box, the binding force of the lithium metal cells is enhanced, and the number of cycles of the cells will be correspondingly improved.

[0034] It should be understood that the above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for forming a multi-module lithium metal solid-state battery carbon fiber multi-grid box, characterized in that: include: (1) Laying a first prepreg on the surface of a cavity of a concave mold, wherein the cavity of the concave mold is a rectangular parallelepiped structure; (2) Providing a split mold, the split mold being a rectangular parallelepiped structure, covering the second prepreg on five surfaces of the split mold, and then pressing it tightly into the mold cavity covered with the first prepreg, with the surface of the split mold not covered with the second prepreg facing away from the bottom of the mold cavity, and covering the side of the split mold that is not in direct contact with the concave mold with a buffer layer; (3) repeating step (2) one or more times to form a preform having a multi-grid structure; (4) The preform is cured to form a multi-grid box having a plurality of grid units, wherein the first prepreg is cured to form an outer shell of the multi-grid box, and the second prepreg and the buffer layer are cured to form a partition, wherein the plurality of grid units are separated by the partition, and the partition comprises a surface layer formed by the second prepreg and a buffer layer sandwiched between the surface layers.

2. The method for forming a multi-module lithium metal solid-state battery carbon fiber multi-grid box according to claim 1, characterized in that: The first prepreg and the second prepreg are both carbon fiber prepregs.

3. The method for forming a multi-module lithium metal solid-state battery carbon fiber multi-grid box according to claim 2, characterized in that: The fiber volume content of the carbon fiber prepreg is 50%-70%, and the resin matrix contained in the carbon fiber prepreg includes at least one of epoxy resin, phenolic resin and polyimide.

4. The method for forming a multi-module lithium metal solid-state battery carbon fiber multi-grid box according to claim 2 or 3, characterized in that: The number of cladding layers of the first prepreg is 13 layers, wherein the directions of the carbon fibers in the surface layers on both sides are 0° and 90°, the direction of the carbon fibers in the middle layer is unidirectional 90°, and the direction of the carbon fibers in the remaining layers is unidirectional 0°; The number of cladding layers of the second prepreg is 8, wherein the directions of the carbon fibers in the surface layers on both sides are 0° and 90°, the direction of the carbon fibers in the middle layer is unidirectional 90°, and the direction of the carbon fibers in the remaining layers is unidirectional 0°; The buffer layer is mainly composed of an elastic material, and the elastic material includes foam formed by at least one of silicone, polyurethane elastomer, and rubber, or the elastic material is PMI foam.

5. The method for forming a multi-module lithium metal solid-state battery carbon fiber multi-grid box according to claim 4, characterized in that: The thickness ratio of the surface layer to the buffer layer in the separator is 1:

3.

6. The method for forming a multi-module lithium metal solid-state battery carbon fiber multi-grid box according to claim 1, characterized in that: The curing treatment comprises: packaging the preform obtained in step (3) with a vacuum bag and placing it in an autoclave, maintaining it at a temperature of 80° C. and a pressure of 3 MPa for 30 minutes, then raising the temperature to 125° C. and the pressure to 5 MPa, and maintaining them for 90 minutes, and finally lowering the temperature to 50° C. and releasing the pressure to normal pressure, thereby completing the curing.

7. The method for forming a multi-module lithium metal solid-state battery carbon fiber multi-grid box according to claim 1, characterized in that: Also includes: After the curing treatment, demoulding is performed and the obtained multi-grid box is subjected to surface treatment.

8. A multi-module lithium metal solid-state battery carbon fiber multi-grid box manufactured by the forming method of a multi-module lithium metal solid-state battery carbon fiber multi-grid box according to any one of claims 1 to 7.

9. The multi-module lithium metal solid-state battery carbon fiber multi-grid box according to claim 8, characterized in that: The overall warping degree of the multi-module lithium metal solid-state battery carbon fiber multi-grid box is within 2 mm.

10. A lithium metal solid-state battery assembly, characterized in that: include: The multi-module lithium metal solid-state battery carbon fiber multi-grid box as described in claim 8 or 9, and the lithium metal solid-state battery module, wherein the multiple lithium metal solid-state batteries contained in the lithium metal solid-state battery module are respectively arranged in multiple grid units of the multi-module lithium metal solid-state battery carbon fiber multi-grid box.

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