Cylindrical battery composite shell and cylindrical battery

Abstract

The utility model relates to battery technology field especially relates to a cylindrical battery composite shell and cylindrical battery, including main casing, positive pole casing and negative pole casing, wherein main casing is the engineering material of high temperature resistance, corrosion resistance, and main casing has the following component composition 70% polyethylene terephthalate, 20% carbon fiber, 5% graphene, 3% flame retardant and 2% heat conducting filler, main casing includes the upper half and the lower half of mutual insulation, and the positive pole casing is connected in the upper half, and the negative pole casing is connected in the lower half. The utility model discloses a cylindrical battery composite shell has higher mechanical performance, and the cylindrical battery of its composition is more easily assembled.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a cylindrical battery composite casing and a cylindrical battery. Background Technology

[0002] Currently, most cylindrical batteries have steel or aluminum casings. Due to the conductivity of metal casings, during battery assembly, measures such as coating the cells with adhesive, adding insulating sheets to the contact parts with the casing, and cell film are required to avoid contact between the positive and negative electrodes. Simultaneously, to ensure the battery's airtightness, sealing rings are added to the cells, achieved through riveting or locking nuts to compress the sealing rings. Because of the numerous components and complex assembly process, this not only reduces cell space and capacity but also results in a lengthy manufacturing process due to the multiple structural component assemblies and laser welding required. Furthermore, battery collisions during production frequently lead to short circuits and fires, affecting product yield, efficiency, and safety, and increasing investment in assembly equipment, significantly raising battery manufacturing costs. Utility Model Content

[0003] In order to overcome the shortcomings of the existing technology, this utility model provides a cylindrical battery composite casing and a cylindrical battery.

[0004] One objective of this invention is to provide a cylindrical battery composite casing, comprising a main casing, a positive electrode casing, and a negative electrode casing. The main casing is made of a high-temperature resistant and corrosion-resistant engineering material and comprises 70% polyethylene terephthalate, 20% carbon fiber, 5% graphene, 3% flame retardant, and 2% thermally conductive filler. The positive and negative electrode casings are made of metallic materials, and the main casing, together with the positive and negative electrode casings, forms a composite casing. Externally, the main casing includes an upper and lower insulated portion. The main casing includes an inner wall and an outer wall. The inner wall surrounds the battery cell, and the outer wall surrounds the inner wall, forming a cavity between the outer and inner walls. A barrier portion is provided within this cavity, dividing the cavity into a first chamber and a second chamber, which are insulated from each other by the barrier portion. The positive electrode housing is matched with and installed into the first chamber. The positive electrode housing is connected to a positive electrode plate for connection with the battery cell, and the negative electrode housing is connected to a negative electrode plate for connection with the battery cell. The positive electrode plate is located at the positive terminal of the battery cell. The positive electrode plate and the positive electrode housing are separate designs; after the battery cell is installed into the main housing, the positive electrode plate is welded and fixed to the positive electrode housing. The negative electrode plate is located at the negative terminal of the battery cell, and the negative electrode plate and the negative electrode housing are integrated designs. An injection port is provided on the positive electrode plate to facilitate the injection of electrolyte. To seal the injection port, the composite housing should also include a cover plate, the edge of which is welded and fixed to the positive electrode plate. The positive electrode plate is fixed to the positive tab of the battery cell by welding; the negative electrode plate is fixed to the negative tab of the battery cell by welding. Both the positive and negative electrode plates have protrusions on the side facing the battery cell, allowing for a closer fit between the positive and negative electrode plates and the battery cell.

[0005] The second objective of this utility model is to provide a cylindrical battery, including the aforementioned cylindrical battery composite casing and a cell disposed in the main casing, wherein the cell is a wound core type.

[0006] The third objective of this utility model is to provide a method for preparing a composite casing for a cylindrical battery, comprising the following steps: (S1) Mix and dry raw materials: 70% polyethylene terephthalate, 20% carbon fiber, 5% graphene, 3% flame retardant and 2% thermally conductive filler; dry at 150~170℃ for 4~6 hours. (S2) Injection molding is performed using a stud injection molding machine. The specific injection parameters are: rear section temperature 260~280℃, middle section temperature 270~290℃, front section temperature 280~300℃, nozzle temperature 280~300℃; mold temperature 120~150℃, injection pressure 80~120MPa, holding pressure 60~100MPa, and cooling time 10~30S.

[0007] This utility model has the following technical effects: (1) In this application, the main shell made of engineering materials and the composite shell composed of positive and negative electrode shells made of conductive materials have higher mechanical strength and stronger resistance to deformation compared with existing shells.

[0008] (2) The main shell has positive and negative barriers in its structure, eliminating the need for subsequent cell coating, film wrapping, and adding insulating sheets, thus optimizing the number of structural components and processing technology, increasing the utilization rate of the internal space of the cell and making the cell capacity higher.

[0009] (3) The battery cells are installed in a composite housing, and only three laser welding processes are performed throughout the process, which reduces the number of welding operations, shortens the manufacturing process, improves product yield and efficiency, and greatly reduces manufacturing costs. Attached Figure Description

[0010] Figure 1 This is an exploded view of the cylindrical battery structure. Figure 2 This is a schematic diagram of the structure at the negative electrode of a cylindrical battery. Figure 3 This is a schematic diagram of the positive electrode structure; Figure 4 This is a cross-sectional view of a cylindrical battery. Figure 5 for Figure 4 Enlarged view of the structure at point A in the middle; Figure 6 This is a schematic diagram of the composite shell structure; Figure 7 for Figure 6 Schematic diagram of the structure at point B; Figure 8 Stress cloud diagram of aluminum alloy shell under stress; Figure 9 This is a stress contour plot of the composite shell under stress. Figure 10 This is a strain contour plot of the aluminum alloy shell under stress. Figure 11 This is a strain contour plot of the composite shell under stress. Figure 12 The diagram shows the adjustment of various parameters of the aluminum alloy shell during the extrusion test; Figure 13 The diagram shows the adjustment of various parameters of the composite shell during the extrusion test.

[0011] In the figure, 100 is the composite shell; 110 is the main shell; 111 is the upper half; 112 is the lower half; 113 is the inner wall; 114 is the outer wall; 115 is the barrier part; 116 is the first chamber; 117 is the second chamber; 118 is the injection port; 119 is the protrusion; 120 is the positive electrode shell; 130 is the negative electrode shell; 140 is the positive electrode plate; 150 is the negative electrode plate; and 160 is the cover plate. Detailed Implementation

[0012] The following examples and Figures 1 to 13 The principles and features of the present invention are described; the examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0013] Example 1 This embodiment provides a cylindrical battery composite housing, the composite housing 100 including a main housing 110, a positive electrode housing 120 and a negative electrode housing 130.

[0014] In terms of materials, the main casing 110 is made of high-temperature resistant and corrosion-resistant engineering materials. Specifically, the main casing 110 is composed of the following components: 70% polyethylene terephthalate (PET), 20% carbon fiber, 5% graphene, 3% flame retardant, and 2% thermally conductive filler. PET serves as the matrix material; carbon fiber acts as a reinforcing material, improving the material's mechanical strength and stiffness while maintaining lightweight characteristics; graphene, as a functional additive, enhances the material's electrical and thermal conductivity, allowing for better heat dissipation in battery applications and preventing thermal runaway; the flame retardant is aluminum hydroxide, which enhances the material's flame retardant performance and ensures battery safety under extreme conditions (such as overheating or short circuits); the thermally conductive filler is boron nitride, which optimizes thermal conductivity, helps the battery casing dissipate heat quickly, and extends battery life. The positive and negative electrode casings are made of metallic materials. The main casing, along with the positive and negative electrode casings, forms a composite casing.

[0015] Structurally, the main housing 110 includes an upper half 111 and a lower half 112 that are insulated from each other. The main housing 110 is generally hollow and cylindrical. The main housing 110 includes an inner wall 113 and an outer wall 114. The inner wall 113 is arranged around the battery cell 200, and the outer wall 114 is arranged around the inner wall 113. A cavity is formed between the outer wall 114 and the inner wall 113. A barrier 115 is provided in the cavity, which divides the cavity into a first chamber 116 and a second chamber 117. The first chamber 116 and the second chamber 117 are insulated from each other by the barrier 115. The positive electrode housing 120 is matched with the first chamber 116 and installed in the first chamber 116. The positive electrode housing 120 is connected to a positive electrode plate 140 for connection with the positive electrode tab of the battery cell, and the negative electrode housing 130 is connected to a negative electrode plate 150 for connection with the negative electrode tab of the battery cell. A positive electrode 140 is disposed at the positive terminal of the battery cell 200. The positive electrode 140 and the positive electrode housing 120 are designed separately. After the battery cell 200 is installed into the main housing 110, the positive electrode 140 is welded and fixed to the positive electrode housing 120. A negative electrode 150 is disposed at the negative terminal of the battery cell 200. The negative electrode 150 and the negative electrode housing 130 are designed as an integral unit, with the outer wall 114 extending to the edge of the negative electrode 150. To facilitate the injection of electrolyte, an injection port 118 is provided on the positive electrode 140. To seal the injection port 118, the composite housing should also include a cover plate 160, the edge of which is welded and fixed to the positive electrode 140. The positive electrode 140 and the negative electrode 150 have protrusions 119 on the side facing the battery cell 200, so that the positive electrode 140 and the negative electrode 150 can fit more closely to the battery cell 200. The protrusion 119 is waist-shaped, and four protrusions 119 are respectively provided on the positive electrode plate 140 and the negative electrode plate 150. The four protrusions 119 are distributed in a circular array.

[0016] Since the battery composite casing in this embodiment is a novel casing, the following verifications were performed to verify its reliability: (1) The composite shell is compared with the common aluminum alloy shell as shown in Table 1 below.

[0017] Table 1. Comparison of structural performance between composite shell and aluminum alloy shell Depend on Figures 8 to 11 As shown in the figure, the analysis revealed that the stress value of the aluminum alloy composite shell (167.1 MPa) was significantly lower than that of the aluminum alloy shell (778.9 MPa), indicating that the material has high mechanical strength. The deformation of the aluminum alloy composite shell (0.1177 mm) was less than that of the aluminum alloy shell (1.225 mm), indicating that the material has good resistance to deformation.

[0018] As can be seen from Table 1 above, the composite shell exhibits high performance in terms of shell weight, energy density, compressive strength, thermal conductivity, needle penetration test pass rate, salt spray test and high temperature cycling decay rate.

[0019] (2) Safety performance test, i.e., extrusion test. Test method: a 75mm radius semi-cylinder, extrusion speed not greater than 2mm / s, stop extrusion after the voltage reaches 0V or the deformation reaches 15% or the extrusion force reaches 100kN or 1000 times the weight of the test object, and observe the results for 10 minutes as shown in Table 2 below. Figures 12 to 13 As shown.

[0020] Table 2 Performance Tests of Batteries with Composite Casings and Batteries with Aluminum Alloy Casings As can be seen from Table 2 above, there is no difference in performance between the composite shell and the existing aluminum alloy shell, proving the feasibility of the application of the composite shell.

[0021] Example 2 A cylindrical battery includes a composite casing 100 and a core 200 as described in Embodiment 1. During assembly, the core 200 is placed into the composite casing 100. The positive and negative electrode tabs of the core 200 are flattened. The positive and negative electrode tabs of the core 200 are simultaneously welded to the positive electrode sheet 140 and the negative electrode sheet 150, respectively. The positive electrode sheet 140 is welded to the positive casing 120, and the cover plate 160 is welded to the positive electrode sheet 140. This reduces the number of welding operations, shortens the manufacturing process, improves product yield and efficiency, and significantly reduces manufacturing costs.

[0022] Example 3 The third objective of this utility model is to provide a method for preparing a composite casing for a cylindrical battery, comprising the following steps: (S1) Proportioning and drying raw materials to avoid melt decomposition and silver streaks or bubbles on the surface of the product: 70% polyethylene terephthalate, 20% carbon fiber, 5% graphene, 3% flame retardant and 2% thermally conductive filler; drying temperature 150~170℃, drying time 4~6 hours.

[0023] (S2) Injection molding is performed using a stud-type injection molding machine. Specific injection parameters are: rear section temperature 260~280℃, middle section temperature 270~290℃, front section temperature 280~300℃, nozzle temperature 280~300℃; mold temperature 120~150℃, injection pressure 80~120MPa, holding pressure 60~100MPa, cooling time 10~30S. This process encases the metal casing internally, achieving insulation between the inner and outer walls, while the area connecting to the battery cell tabs is exposed. Insulation at the connection point prevents overlap between the positive and negative electrode casings, forming an integrated composite shell. The casing shape can be round, square, or other irregular shapes, customized according to the battery shape and size, with a diameter of 10mm-200mm. The thickness can be customized from 0.1mm-5mm according to the battery structure.

[0024] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A composite casing for a cylindrical battery, characterized in that, include: The main housing includes an upper half and a lower half that are insulated from each other; A positive electrode housing, the positive electrode housing being covered by an upper half, and a positive electrode plate connected to the positive electrode housing for connection with the battery cell; The negative electrode housing is covered by a lower half and is connected to a negative electrode plate for connection with the battery cell.

2. The cylindrical battery composite casing according to claim 1, characterized in that, The main housing includes an inner wall and an outer wall. The inner wall is arranged around the battery cell, and the outer wall is arranged around the inner wall. A cavity is formed between the inner wall and the outer wall. A barrier is provided in the cavity, which divides the cavity into a first chamber and a second chamber. The positive electrode housing is placed in the first chamber, and the negative electrode housing is placed in the second chamber.

3. The cylindrical battery composite casing according to claim 1, characterized in that, The positive electrode housing and the positive electrode plate are designed separately, with the positive electrode plate located at the positive end of the battery cell and welded to the positive electrode housing; the negative electrode housing and the negative electrode plate are designed as an integral unit, with the negative electrode plate located at the negative end of the battery cell and welded to the negative electrode housing.

4. The cylindrical battery composite casing according to claim 3, characterized in that, The positive and negative electrode plates have protrusions on the side facing the battery cell.

5. The cylindrical battery composite casing according to claim 3, characterized in that, The outer wall extends to the edge of the negative electrode sheet.

6. The cylindrical battery composite casing according to claim 3, characterized in that, It also includes a cover plate, and the positive electrode sheet is provided with an injection port at the position of the injection cavity of the battery cell. The cover plate is welded and fixed to the positive electrode sheet.

7. The cylindrical battery composite casing according to claim 1, characterized in that, The main housing is made of insulating material.

8. A cylindrical battery, characterized in that, It includes the cylindrical battery composite casing as described in any one of claims 1 to 7 and the battery cell disposed within the main casing.

9. The cylindrical battery according to claim 8, characterized in that, The battery cell is a wound-core type.

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