Large cylindrical battery cell and large cylindrical battery cell module

Abstract

The invention discloses a large cylindrical battery cell and a large cylindrical battery cell module. The large cylindrical battery cell comprises a shell of a cylindrical structure, a plurality of tooth grooves are formed in the outer surface of the shell of the cylindrical structure in the length direction of the large cylindrical battery cell, the tooth grooves rotate around the axis of the large cylindrical battery cell and are arranged at intervals, and the tooth grooves extend from one end of the large cylindrical battery cell to the other end of the large cylindrical battery cell to form a through groove structure. According to the large cylindrical battery cell provided by the invention, the spline-shaped shell is formed on the surface of the battery cell shell through the plurality of tooth grooves, so that the area of the surface of the battery cell is increased, the heat dissipation efficiency of the battery cell can be improved to a certain extent, the temperature uniformity is improved, and the systematicness of the safety performance of the battery is improved; and the technical bottleneck of the traditional cylindrical battery in height expansion and transverse layout is broken through.

Description

Technical Field

[0001] This invention relates to the field of large cylindrical battery cell technology, and in particular to a large cylindrical battery cell and a large cylindrical battery cell module. Background Technology

[0002] With the introduction of large cylindrical battery cells (such as the Tesla 4680), research on large-size cylindrical battery cells is increasing. Compared with traditional cylindrical battery cells, large cylindrical battery cells generate higher temperatures during charging and discharging due to their increased size and capacity. While large cylindrical battery cells offer advantages such as high energy density and standardized production when assembled into battery systems, they primarily rely on serpentine water-cooled plates for heat dissipation. Although this approach offers high heat dissipation efficiency, it suffers from structural complexity, a large number of components, and high cost. Furthermore, it exhibits significant disadvantages in terms of heat dissipation, specifically as follows: 1. Low heat dissipation efficiency: mismatch between surface area and volume ratio Cylindrical battery cells primarily rely on the curved surface contact of their side circumference for heat dissipation. However, as the volume of large cylindrical cells increases, the surface area to volume ratio (SA / V) of individual cells actually decreases, making it more difficult for internal heat to be quickly dissipated through the surface. Furthermore, the increased size of large cylindrical cells reduces the gaps between cells, limiting the design of heat dissipation channels and causing heat to tend to accumulate in the center.

[0003] 2. High complexity of thermal management after grouping. When cylindrical cells are assembled into modules, they need to be connected in series or parallel. However, the contact surfaces between cells are mostly point or line contacts, rather than the surface contacts of square cells. The liquid cooling pipeline layout needs to surround the cells, which takes up space and reduces energy density. Existing solutions (such as serpentine liquid cooling pipes or thermally conductive potting) are difficult to balance heat dissipation efficiency and compact assembly.

[0004] 3. Temperature uniformity challenge When the battery system is charged and discharged at high rates, the large cylindrical cells are prone to uneven heat dissipation, which can lead to inconsistent temperature distribution within the module and affect its lifespan and performance.

[0005] 4. Height limitations of cylindrical battery cells Currently, the height of mass-produced large cylindrical cells is mostly between 80mm and 120mm (e.g., 80mm for 4680 and 95mm for 4695). Increasing the height will reduce the bending stiffness of the cylindrical shell (steel / aluminum), making it prone to deformation under vibration or impact, which can lead to short circuits due to pressure on the internal electrode plates. Furthermore, increasing the height will further deteriorate the heat dissipation efficiency. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings and defects of existing large cylindrical battery cells, and to provide a large cylindrical battery cell with a larger heat dissipation area and the ability to dissipate heat quickly, as well as a large cylindrical battery cell module using the large cylindrical battery cell.

[0007] One object of the present invention is to provide a large cylindrical battery cell, including a cylindrical shell, wherein a plurality of grooves are formed on the outer surface of the cylindrical shell along the length direction of the large cylindrical battery cell, the grooves are arranged to be rotated apart around the axis of the large cylindrical battery cell, and the grooves extend from one end of the large cylindrical battery cell to the other end to form a through groove structure.

[0008] Preferably, the plurality of the grooves are distributed at equal angles on the circumference of the outer casing.

[0009] Preferably, the tooth groove includes a straight groove.

[0010] Preferably, the cross-section of the tooth groove is one of a rectangle, trapezoid, or triangle.

[0011] Preferably, the bottom of the outer casing has explosion-proof grooves.

[0012] Preferably, the surface of the outer casing has an insulating and thermally conductive layer that fully covers the circumferential surface of the outer casing.

[0013] Preferably, the insulating and thermally conductive layer is an insulating and thermally conductive coating applied to the surface of the outer casing or an insulating and thermally conductive film attached to the surface of the outer casing.

[0014] One objective of this invention is to provide a large cylindrical battery cell module, comprising a plurality of large cylindrical batteries, wherein the axes of the plurality of large cylindrical batteries are arranged parallel to the bottom plate of the lower housing of the module and are stacked together in an alternating manner, the grooves of adjacent large cylindrical batteries are engaged in the circumferential direction of the outer shell, and a liquid cooling medium channel is formed between every three large cylindrical batteries.

[0015] Preferably, multiple large cylindrical battery cells are stacked to form two sets of battery cell stacks. The two sets of battery cell stacks are arranged on both sides of a flow-guiding and exhaust plate that is perpendicular to the bottom plate of the lower housing. The bottoms of the battery cells are opposite each other and each is connected to an outer side of the flow-guiding and exhaust plate. An exhaust channel is formed inside the flow-guiding and exhaust plate and communicates with multiple holes on the outer side of the flow-guiding and exhaust plate. Each hole corresponds to the bottom explosion-proof valve of a large cylindrical battery cell. Multiple through holes are arranged in the exhaust channel. Each liquid cooling medium channel is connected to one of the through holes to realize the entry / exit of liquid cooling medium into / out of the liquid cooling channel and cool the surface of the large cylindrical battery cell.

[0016] Preferably, the bottom surface of the lower housing is provided with a limiting groove that matches the toothed groove shape of the outer shell surface.

[0017] The large cylindrical battery cell provided by this invention increases the surface area of ​​the battery cell shell by forming gear-like or spline-like grooves on the surface of the battery cell shell. This can improve the heat dissipation efficiency of the battery cell to a certain extent, improve temperature uniformity, and enhance the systematic performance of battery safety. It breaks through the technical bottleneck of traditional cylindrical batteries in terms of height expansion and horizontal layout. Attached Figure Description

[0018] Figure 1 This is a three-dimensional schematic diagram of a large cylindrical battery cell according to the first embodiment of the present invention.

[0019] Figure 2 This is another three-dimensional schematic diagram of the large cylindrical battery cell according to the first embodiment of the present invention.

[0020] Figure 3 This is a three-dimensional schematic diagram of six large cylindrical battery cells stacked together according to the first embodiment of the present invention.

[0021] Figure 4 This is a front view schematic diagram of six large cylindrical battery cells stacked together according to the first embodiment of the present invention.

[0022] Figure 5 This is a three-dimensional schematic diagram of a large cylindrical battery cell according to the second embodiment of the present invention.

[0023] Figure 6 This is a three-dimensional schematic diagram of a large cylindrical battery cell according to the third embodiment of the present invention.

[0024] Figure 7 This is a three-dimensional schematic diagram of the 46300 large cylindrical battery cell according to the fourth embodiment of the present invention.

[0025] Figure 8 This is a three-dimensional schematic diagram of the 46300 large cylindrical battery cells assembled and connected with the exhaust guide plate according to the fourth embodiment of the present invention.

[0026] Figure 9 This is a front view schematic diagram of the 46300 large cylindrical battery cells assembled and connected with the exhaust guide plate according to the fourth embodiment of the present invention.

[0027] Figure 10 This is a schematic diagram of a large cylindrical cell module formed by assembling 46300 large cylindrical cells in a housing according to the fourth embodiment of the present invention.

[0028] Figure 11 This is a schematic diagram of the liquid cooling medium flow in a large cylindrical cell module formed by assembling 46300 large cylindrical cells in a housing according to the fourth embodiment of the present invention. Detailed Implementation

[0029] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0030] In this embodiment of the application, the large cylindrical battery cell mainly includes cylindrical battery cells with a height of 80mm-120mm, such as the 4680 large cylindrical battery cell with a height of 80mm and the 4695 large cylindrical battery cell with a height of 95mm, and a general diameter of 46mm.

[0031] See Figure 1 As shown, this application embodiment provides a large cylindrical battery cell structure, including a cylindrical outer shell 1. On the outer surface of the cylindrical outer shell, a plurality of grooves 11 are formed along the length direction or axial direction of the large cylindrical battery cell. The grooves 11 are arranged to rotate around the axis of the large cylindrical battery cell and are spaced apart. The grooves extend from one end of the large cylindrical battery cell to the other end to form a through groove structure. This design makes the outer shell of the large cylindrical battery cell form a gear-shaped or spline-shaped shell.

[0032] In this embodiment, the cylindrical shell of the large cylindrical battery cell is made of extruded aluminum profile, which can be cut according to the design height of the large cylindrical battery cell. For large cylindrical battery cells of the same radius, only one set of molds needs to be prepared, which is highly versatile and saves costs. Compared with the conventional cylindrical shape, the gear-shaped or spline-shaped battery cell shell has a larger heat dissipation area, which can dissipate heat quickly and increase the surface area to volume ratio of the single cell, so that the internal heat can be quickly conducted away through the surface.

[0033] As mentioned earlier, the height of large cylindrical battery cells is limited by their structural form. For example, increasing the height reduces the bending stiffness of the cylindrical shell, making it prone to deformation under vibration or impact, leading to short circuits due to pressure on the internal electrodes. The gear-shaped or spline-shaped battery cell shell structure of the embodiments in this application enhances its structural strength, enabling the fabrication of taller cells. Simultaneously, its better heat dissipation also mitigates the impact of increased height on heat dissipation efficiency.

[0034] like Figure 2 As shown, in one embodiment, the bottom of the casing has explosion-proof markings 12. The explosion-proof markings 12 on the bottom of the battery cell are mainly used to ensure that in the event of thermal runaway, the instantaneously generated high-temperature and high-pressure gas can blast open this area, thereby achieving the effect of explosion venting. The explosion-proof markings 12 can be of a corresponding geometric shape, such as a C-shape, or other shapes.

[0035] This application embodiment increases the surface area of ​​the battery cell casing by forming a gear-shaped or spline-shaped shell through multiple grooves on the surface of the battery cell casing. This can improve the heat dissipation efficiency of the battery cell to a certain extent, improve the temperature uniformity of the battery, and thus improve the safety performance of the battery system, breaking through the technical bottleneck of traditional cylindrical batteries in high expansion and horizontal layout.

[0036] In one implementation, the plurality of grooves are distributed at equal angles or uniformly on the circumference of the outer shell. Of course, in specific implementations, it is not limited to this and can also be distributed non-uniformly or non-equiangularly. Preferably, they are distributed at equal angles or uniformly on the circumference of the outer shell.

[0037] In one embodiment, the groove is a straight groove extending from one end of the large cylindrical battery cell to the other end to form a through-groove structure. The cross-section of the groove is rectangular, trapezoidal, triangular, or other geometric shapes, and is not limited to these. Figure 5 , Figure 6 As shown, Figure 5 In the large cylindrical battery cell shown, the shape of its slots is similar to... Figure 1 Similar to the large cylindrical battery cell shown in the embodiment, it has a spline-like structure, differing only in the tooth width. Figure 1 As shown, the tooth width is relatively narrow. Figure 6 The large cylindrical battery cell shown has a tooth structure similar to that of a gear, with triangular teeth and trapezoidal grooves.

[0038] Preferably, the grooves on the surface of the outer casing are of uniform shape and size. In this embodiment, the height of the teeth in the grooves is uniform or the outer diameter is the same.

[0039] In one embodiment, the surface of the housing has an insulating and thermally conductive layer that completely covers the circumferential surface of the housing. In a preferred embodiment, the insulating and thermally conductive layer is an insulating and thermally conductive coating applied to the surface of the housing or an insulating and thermally conductive film attached to the surface of the housing, such as an alumina coating or a boron nitride film.

[0040] like Figure 3 , Figure 4 The diagram shows a schematic of the large cylindrical battery cells stacked in the above embodiments of this application. The space between the three large cylindrical battery cells serves as a liquid cooling medium channel 2 for the flow of the liquid cooling medium. In the embodiments of this application, when the large cylindrical battery cells are stacked, the outer shells 1 of the gear-shaped or spline-shaped cells are in contact with each other. Compared to conventional cylindrical battery cells, the contact between the large cylindrical battery cells in this application is changed from line contact to surface contact, increasing the contact area and improving heat conduction. Figure 3 , Figure 4 As shown, the six gear-shaped or spline-shaped shells of a large cylindrical cell (center) are all matched with the gear-shaped or spline-shaped shells of adjacent cells. The liquid cooling medium channel 2 includes the increased contact area corresponding to the tooth grooves on the shell surface, which increases the heat conduction area between cells and improves the temperature uniformity, thereby enhancing the temperature uniformity of the battery.

[0041] This application embodiment also provides a large cylindrical battery cell module, including multiple large cylindrical batteries. The axes of the multiple large cylindrical batteries are arranged parallel to the bottom plate of the lower housing of the module and are stacked together in an alternating manner. The grooves of adjacent large cylindrical batteries are engaged in the circumferential direction of the outer shell, and a liquid cooling medium channel is formed between every three large cylindrical batteries.

[0042] In one implementation, multiple large cylindrical battery cells are stacked to form two sets of battery cell stacks. The two sets of battery cell stacks are arranged on both sides of a flow-guiding and exhaust plate that is perpendicular to the bottom plate of the lower housing. The bottoms of the battery cells are opposite each other and each is connected to an outer side of the flow-guiding and exhaust plate. An exhaust channel is formed inside the flow-guiding and exhaust plate and communicates with multiple holes on the outer side of the flow-guiding and exhaust plate. Each hole corresponds to the bottom explosion-proof valve of a large cylindrical battery cell. Multiple through holes are arranged in the exhaust channel. Each liquid cooling medium channel is connected to one of the through holes to realize the entry / exit of the liquid cooling medium into / out of the liquid cooling channel and cool the surface of the large cylindrical battery cell.

[0043] In one embodiment, the bottom surface of the lower housing is provided with a limiting groove that matches the toothed shape of the outer shell surface. For example... Figure 10 As shown, there are multiple limiting grooves 54 at the bottom of the lower housing that match the shape of the outer shell surface of the large cylindrical battery cell, evenly distributed on the inner bottom surface of the lower housing. The lower housing has a matching cover 51 and four side walls or enclosures, which, together with the bottom of the lower housing, define a battery space inside the lower housing for placing the battery module. The large cylindrical battery cell is installed by using the limiting grooves 54 to be snapped into the limiting grooves 54 through the toothed grooves 11 on its outer surface. This not only enables tool-free and rapid assembly of the battery cell, but also allows for heat dissipation through the battery housing by the surface contact between the battery cell and the bottom of the housing, increasing the heat dissipation area and improving heat dissipation efficiency.

[0044] Taking the 46300 large cylindrical battery cell 3 as an example, the assembly method of the battery cell is as follows: Figures 7 to 11 As shown, the 46300 large cylindrical cells are stacked flat, and the battery module formed by two rows of stacked cells can be used in commercial vehicle systems. The flat stacking method is also more suitable for the scenario where the height space of commercial vehicles is variable, making it more practical.

[0045] like Figures 7 to 11As shown, the axes of multiple 46300 (46 mm in diameter, 300 mm in length) large cylindrical cells 3 are arranged parallel to the bottom plate of the lower housing 5 of the module, and are stacked together in an alternating manner. The teeth of the grooves of adjacent large cylindrical cells are engaged in the circumferential direction of the outer shell. A liquid cooling medium channel is formed between every three 46300 large cylindrical cells. The 46300 large cylindrical cells are stacked to form two sets of cell stacks. The two sets of cell stacks are arranged on both sides of the guide and exhaust plate 4, which is arranged perpendicular to the bottom plate of the lower housing 5. The space formed by the close stacking of cells is simple in structure and has a high space utilization rate.

[0046] The airflow guide plate 4 is located at the central axis of the lower housing. An exhaust channel 43 is formed inside the airflow guide plate 4 and communicates with multiple holes 42 on the outer side of the airflow guide plate. Each hole 42 corresponds to the bottom explosion-proof valve 12 of a large cylindrical battery cell. Multiple through holes 41 are arranged in the exhaust channel, and each liquid cooling medium channel is connected to one of the through holes 41, allowing the liquid cooling medium to enter / exit the liquid cooling channel and cool the surface of the large cylindrical battery cell.

[0047] In this embodiment, the through-hole 41 is a channel for the flow of submerged coolant. The triangular space formed by the close fit between every three cells serves as a channel for coolant flow. The coolant within the triangular space is confined to a directional flow between the three large cylindrical cells, avoiding flow dead zones caused by chaotic coolant flow and resulting in large temperature differences. The coolant flow channel between every three large cylindrical cells cooperates with the through-hole 41 on the exhaust plate to form a complete submerged coolant flow channel, realizing the circulation of submerged coolant in the large cylindrical cells.

[0048] Compared to conventional cylindrical cells, in this embodiment, the structure of the gear-shaped or spline-shaped outer surface of the casing also increases the contact area with the coolant to a certain extent, resulting in high space utilization and eliminating the need for a dedicated flow channel design, thus saving material and labor costs.

[0049] In this embodiment, the space formed by the gears or splines on the outer surface of the battery cell serves as a channel for the flow of submerged coolant. The close fit between three battery cells also forms a channel for coolant flow, avoiding dead zones caused by turbulent coolant flow. This, combined with the through holes on the exhaust guide plate at the bottom of the battery cell, forms a complete submerged coolant flow channel, achieving coolant circulation and efficient heat dissipation. The contact area between the gears or splines and the coolant is also increased, resulting in high space utilization and eliminating the need for a dedicated flow channel design, thus saving material and labor costs.

[0050] In this embodiment, the bottom of the battery cell is connected to an explosion-proof venting channel, which ensures high safety; all battery cells share a single venting channel, and this component also serves as a coolant flow channel, resulting in high space utilization.

[0051] In this embodiment, when thermal runaway occurs in the battery cell, the sealing structure on the bottom plane fails. A portion of the high-temperature gas undergoes initial pressure relief through the explosion-proof valve 12 at the bottom of the battery cell. Subsequently, most of the high-temperature gas enters the exhaust channel 43 through the hole 42 and is guided to the explosion-proof valve at the rear of the housing for discharge. Furthermore, this embodiment features a design that separates the exhaust channel 43 from the cooling oil, preventing the high-temperature gas from igniting the coolant, resulting in a safer structural design.

[0052] In this embodiment of the application, when the cell module composed of large cylindrical cells is working, such as Figure 11 As shown, the coolant enters the housing through the system inlet 53, flows through the space at the top of the large cylindrical battery cells, and then flows to the rear of the housing. Simultaneously, it flows through the space between the large cylindrical battery cells and the through-hole 41 on the exhaust guide plate 4 to the other side of the housing, finally returning to the outlet 52 at the front for discharge. The red arrows in the figure indicate the coolant flow channels and / or directions.

[0053] In this embodiment of the large cylindrical battery cell, when the cell heats up, the heat can be quickly dissipated through the gear or spline structure on the outer surface. Compared with traditional structures, the heat dissipation area to the air is larger; and the heat conduction area in the height direction is also larger, which can guide the heat to the bottom of the cell as much as possible, and then conduct it to the bottom of the casing. Regardless of whether the system uses natural cooling, bottom liquid cooling, or immersion liquid cooling, the heat dissipation effect is better than that of traditional structures, effectively improving the problem of poor heat dissipation of large cylindrical battery cells.

[0054] The large cylindrical battery cell of this application, due to its novel structure, has a large heat conduction area at the top and bottom, which makes the temperature more uniform along the height direction. At the same time, it allows for surface contact between the battery cells, and the heat between the cells can be transferred quickly through the contact surface, reducing the temperature difference between the cells and improving temperature uniformity. This solves the problem of high internal temperature and poor temperature uniformity in large cylindrical battery cells.

[0055] Increasing the height of a large cylindrical battery cell reduces the bending stiffness of the cylindrical shell (steel / aluminum), making it prone to deformation under vibration or impact. This can lead to short circuits in the internal electrode plates and further deteriorate heat dissipation efficiency. The large cylindrical battery cell of this application provides higher mechanical strength. Simultaneously, its excellent heat dissipation performance improves heat dissipation efficiency and reduces internal heat accumulation, allowing for an increase in the height of the large cylindrical battery cell and breaking through the height bottleneck.

[0056] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of the equivalents of the claims be included within the invention.

[0057] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A large cylindrical battery cell, characterized in that, The device includes a cylindrical outer shell, on the outer surface of which a plurality of grooves are formed along the length of the large cylindrical battery cell. The grooves are arranged to rotate around the axis of the large cylindrical battery cell and are spaced apart. The grooves extend from one end of the large cylindrical battery cell to the other end to form a through-groove structure.

2. The large cylindrical battery cell according to claim 1, characterized in that, The plurality of the grooves are distributed at equal angles on the circumference of the outer casing.

3. The large cylindrical battery cell according to claim 1, characterized in that, The tooth groove includes a straight groove.

4. The large cylindrical battery cell according to claim 1, characterized in that, The cross-section of the tooth groove is one of rectangle, trapezoid, or triangle.

5. The large cylindrical battery cell according to claim 1, characterized in that, The bottom of the casing has explosion-proof markings.

6. The large cylindrical battery cell according to claim 1, characterized in that, The surface of the outer casing has an insulating and thermally conductive layer that completely covers the circumferential surface of the outer casing.

7. The large cylindrical battery cell according to claim 6, characterized in that, The insulating and thermally conductive layer is an insulating and thermally conductive coating applied to the surface of the outer casing or an insulating and thermally conductive film attached to the surface of the outer casing.

8. A large cylindrical battery cell module, characterized in that, The device includes a plurality of large cylindrical cells as described in any one of claims 1-7, wherein the axes of the plurality of large cylindrical cells are arranged parallel to the bottom plate of the lower housing of the module and are stacked together in an alternating manner, the grooves of adjacent large cylindrical cells are engaged in the circumferential direction of the outer shell, and a liquid cooling medium channel is formed between every three large cylindrical cells.

9. The large cylindrical cell module according to claim 8, characterized in that, Multiple large cylindrical battery cells are stacked to form two sets of battery cell stacks. The two sets of battery cell stacks are arranged on both sides of a flow guide and exhaust plate that is perpendicular to the bottom plate of the lower housing. The bottoms of the battery cells are opposite each other and each is connected to an outer side of the flow guide and exhaust plate. An exhaust channel is formed inside the flow guide and exhaust plate and communicates with multiple holes on the outer side of the flow guide and exhaust plate. Each hole corresponds to the bottom explosion-proof valve of a large cylindrical battery cell. Multiple through holes are arranged in the exhaust channel. Each liquid cooling medium channel is connected to one of the through holes to realize the entry / exit of liquid cooling medium into and out of the liquid cooling channel to cool the surface of the large cylindrical battery cell.

10. The large cylindrical cell module according to claim 8, characterized in that, The bottom surface of the lower housing is provided with a limiting groove that matches the toothed groove shape of the outer shell surface.

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