Cylindrical lithium-ion cell and battery pack

Abstract

The utility model provides a cylindrical lithium ion electric core and battery pack, including metal shell, upper cover, lower cover, positive pole piece, negative pole piece, diaphragm, electrolyte and hollow tube, positive pole piece, negative pole piece and diaphragm are around the hollow tube winding setting, and the support structure around the hollow tube is set to the end of hollow tube, this scheme makes the structure of electric core inside more stable, and the hollow tube in the electric core increases the direct path of additional heat conduction, can promote the heat even distribution of electric core itself, can also effectively transmit the heat from the battery inside.

Description

Technical Field

[0001] This utility model relates to the technical field of lithium-ion battery cells, and in particular to a cylindrical lithium-ion battery cell with strong heat exchange capability and a battery pack composed of the battery cell. Background Technology

[0002] Lithium-ion cells have been widely used in power batteries and electrochemical energy storage due to their advantages such as high energy density, long cycle life, and low self-discharge rate. However, lithium-ion cells generate a lot of heat during use, which can easily lead to heat accumulation, causing a rapid rise in temperature and even thermal runaway. Furthermore, battery packs composed of hundreds or thousands of individual lithium-ion cells often suffer from uneven temperature distribution, resulting in rapid battery life degradation and serious safety issues. Therefore, reasonable and effective thermal management of battery packs is essential.

[0003] To improve the heat dissipation efficiency of battery packs, cooling pipes that can contact and exchange heat with the lithium-ion cell casing are typically used. In particular, to increase the heat exchange area with the cell, flat cooling pipes or heat pipes can be used to exchange heat with the cell, further increasing the heat exchange capacity of the battery pack. However, due to the limited surface area and heat transfer capacity of the lithium-ion cell, battery packs still suffer from low heat exchange efficiency and uneven temperature distribution. Utility Model Content

[0004] This utility model provides a cylindrical lithium-ion battery cell, comprising a metal casing, an upper cover, a lower cover, a positive electrode, a negative electrode, a separator, and an electrolyte. The upper cover is connected to the positive electrode, the lower cover is connected to the negative electrode, and the lower cover is directly connected to the metal casing. The upper cover and the metal casing are fixed together by an insulating layer. The positive electrode, negative electrode, and separator are wound around a hollow tube, which is cylindrical. The hollow tube is directly connected to either the lower or upper cover. A support structure is provided around the end of the hollow tube, including a first disc-shaped structure and a second disc-shaped structure. The upper or lower cover is disposed between the first and second disc-shaped structures through an insulating layer. The upper or lower cover is insulated from both the first and second disc-shaped structures. A heat-conducting layer is disposed between the composite wound of the positive electrode, negative electrode, and separator and the hollow tube. A circular through-hole is included.

[0005] The upper or lower cover is fixed to the metal casing through an insulating layer, which improves the overall insulation capability of the battery cell. The other cover is directly connected to the metal casing, which enhances the stability of the overall battery cell structure.

[0006] The top or bottom cover is fixed to the metal casing by an insulating layer, and the top or bottom cover and the first and second disc-shaped structures are also insulated. This multi-layer insulation design effectively prevents short circuits between the positive and negative electrodes, avoiding safety accidents such as overheating, fire, or even explosion caused by short circuits, and greatly improving the safety and stability of the cylindrical lithium-ion cell during use.

[0007] For example, when the battery cell is subjected to external impact or vibration, the insulating layers of the first and second disc-shaped structures can play a double insulating role, effectively preventing the top cover from accidentally contacting conductive components such as the metal casing, and ensuring the normal operation of the battery cell.

[0008] The positive electrode, negative electrode, and separator are wound around the hollow tube, and the hollow tube is connected to the circular through hole of the lower cover. At the same time, the support structure at the end of the hollow tube (the first disc structure and the second disc structure) provides good support and positioning for the upper cover, making the internal structure of the cell more stable and able to effectively resist external impact and vibration.

[0009] When battery cells are used in devices subject to significant vibration, such as electric vehicles, the hollow tubes make the internal structure of the cell more stable, ensuring that the electrodes and separators do not shift or become damaged due to vibration, thus extending the cell's lifespan. Furthermore, the hollow tubes within the cell add an extra direct path for heat conduction, promoting more even heat distribution within the cell and effectively transferring heat away from the battery's interior.

[0010] Preferably, the first and second disc-shaped structures are connected, and their projections on the radial plane form a C-shaped structure. This design provides more support and protection within a limited space, improving space utilization while also providing additional mechanical support to help resist external impacts and protect sensitive components inside the battery cell.

[0011] Preferably, one end of the hollow tube is provided with an annular bulge around the axis of the cylindrical lithium-ion cell, which supports the top cover. This design provides additional support points, which helps to fix the top cover, enhances the overall structural stability of the cell, and the annular bulge particularly improves the heat accumulation of the top cover, quickly conducting the heat of the top cover to the outside, thereby improving the temperature uniformity of the cell.

[0012] Preferably, the upper cover is provided with a connecting structure, which is disposed between the first disc-shaped structure and the second disc-shaped structure. The connecting structure is arranged around the hollow tube, and is insulated from the first disc-shaped structure and from the second disc-shaped structure.

[0013] Preferably, the axial height of the connection structure combined with the first disc-shaped structure is lower than the height of the top cover. This design allows most of the top cover to bear external pressure, providing better mechanical support and resulting in a flatter overall surface for the top cover, thus improving the space utilization of the assembly.

[0014] Preferably, the first and second disc-shaped structures are connected and rounded. This design helps improve the heat flow path inside the cell, promotes more efficient heat conduction and dissipation, and improves thermal management efficiency.

[0015] Preferably, the metal casing includes cylindrical and square metal casings. This design increases the flexibility of cylindrical lithium-ion cells and can be applied effectively in both cylindrical and square metal casings.

[0016] Preferably, the composite winding of the positive electrode, negative electrode, and separator is cylindrical, with a radius R and a height H, and the radius r of the hollow tube, all in mm, and 2(R+r) / (R²-r²)+2 / H≥0.05. This design effectively improves the heat exchange capacity of the hollow tube to the battery cell. If 2(R+r) / (R²-r²)+2 / H<0.05, it weakens the heat dissipation improvement of the hollow tube to the battery cell, thus reducing the heat dissipation improvement of the hollow tube to the battery cell.

[0017] More preferably, 2(R+r) / (R2-r2)+2 / H≥0.07, and for power batteries, the preferred value is: 2(R+r) / (R2-r2)+2 / H≥0.07. 2 -r 2 )+2 / H≥0.1.

[0018] Preferably, the hollow tube is provided with axially extending fins. The end of the fin near the upper cover is the first end, and the ratio of the height of the first end to the radius of the hollow tube is selected from 1:4 to 1:8. The end of the fin near the lower cover is the second end, and the ratio of the height of the first end to the second end is selected from 1:2 to 1:4. After the airflow enters through the through hole in the upper cover, the flow velocity increases through the second end. According to Bernoulli's principle, when a fluid flows in a pipe, an increase in flow velocity leads to a decrease in pressure, thereby accelerating the outflow of the airflow after heat exchange, which is more beneficial to the battery cell.

[0019] This utility model also discloses a battery pack, including the aforementioned cylindrical lithium-ion cells. A liquid cooling pipe is disposed within the hollow tube of each cylindrical lithium-ion cell, and the liquid cooling pipes of adjacent cylindrical lithium-ion cells are interconnected. This design allows the liquid cooling pipes to quickly dissipate the heat generated by the cylindrical lithium-ion cells, thereby improving the overall heat dissipation capacity and temperature uniformity of the battery pack.

[0020] This utility model also discloses a battery pack, including the aforementioned cylindrical lithium-ion cells. A cooling module is installed within the battery pack, generating a cooling airflow that passes through the hollow tube of the cylindrical lithium-ion cells. This design utilizes external air cooling to quickly remove the heat generated by the cylindrical lithium-ion cells, thereby improving the overall heat dissipation capacity and temperature uniformity of the battery pack. Attached Figure Description

[0021] Figure 1 This is a perspective view of a cylindrical lithium-ion battery cell disclosed in this utility model;

[0022] Figure 2 This is a front view of a cylindrical lithium-ion battery cell disclosed in this utility model;

[0023] Figure 3 This is a rear view of a cylindrical lithium-ion battery cell disclosed in this utility model;

[0024] Figure 4 This is a cross-sectional view of a cylindrical lithium-ion battery cell disclosed in this utility model;

[0025] Figure 5 This is a perspective view of another cylindrical lithium-ion battery cell disclosed in this utility model;

[0026] Figure 6 This is a perspective view of another cylindrical lithium-ion battery cell disclosed in this utility model;

[0027] Figure 7 This is a perspective view of another cylindrical lithium-ion battery cell disclosed in this utility model;

[0028] Among them, 1. metal shell, 11. top cover, 12. bottom cover, 13. through hole, 14. connecting structure, 2. hollow tube, 21. supporting structure, 211. first disc structure, 212. second disc structure, 22. annular bulge. Detailed Implementation

[0029] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Example 1

[0031] like Figure 1-4As shown, this embodiment discloses a cylindrical lithium-ion battery cell, the structure of which includes the following components: a metal casing 1, an upper cover 11, a lower cover 12, a positive electrode, a negative electrode, a separator, and an electrolyte. In this design, the upper cover 11 is connected to the positive electrode, while the lower cover 12 is connected to the negative electrode, and the lower cover 12 is directly connected to the metal casing 1. A through hole 13 is provided at the center of the lower cover 12, and the upper cover 11 is fixed to the metal casing 1 by an insulating layer. The positive electrode, the negative electrode, and the separator are wound around a hollow tube 2, which is connected to the through hole 13 of the lower cover 12. At the end of the hollow tube 2, a support structure 21 is provided around the hollow tube 2, the support structure 21 including a first disc-shaped structure 211 and a second disc-shaped structure 212. The upper cover 11 is disposed between the two disc-shaped structures by an insulating layer, and the upper cover 11 is insulated from both disc-shaped structures. A heat-conducting layer is also provided between the composite wound body consisting of the positive electrode, the negative electrode, and the diaphragm and the hollow tube 2 to enhance the heat conduction efficiency.

[0032] Furthermore, the first disc-shaped structure 211 and the second disc-shaped structure 212 are interconnected, and their projections on the radial plane form a C-shaped structure. This design provides more support and protection within a limited space, not only improving space utilization but also providing additional mechanical support to help resist external impacts and protect sensitive components inside the battery cell.

[0033] Furthermore, one end of the hollow tube 2 is provided with an annular protrusion 22 surrounding the axis of the cylindrical lithium-ion cell, which serves to support the upper cover 11. The upper cover 11 is also provided with a connecting structure 14, which is located between the first disc-shaped structure 211 and the second disc-shaped structure 212, and is arranged around the hollow tube 2, while being insulated from both disc-shaped structures. This design further enhances the structural stability and safety of the cell.

[0034] Furthermore, the upper cover 11 is provided with a connecting structure 14, which is positioned between the first disc-shaped structure 211 and the second disc-shaped structure 212. The connecting structure 14 surrounds the hollow tube 2 and is insulated from both the first disc-shaped structure 211 and the second disc-shaped structure 212. The axial height of the connecting structure 14 and the first disc-shaped structure 211 is lower than the height of the upper cover 11. The first disc-shaped structure 211 and the second disc-shaped structure 212 are connected and have a rounded transition. This design helps improve the heat flow path inside the battery cell, promotes more efficient heat conduction and dissipation, and improves thermal management efficiency.

[0035] In this embodiment, the metal shell 1 is a cylindrical metal shell 1, the through hole 13 is circular, the hollow tube 2 is cylindrical, the composite winding of the positive electrode plate, negative electrode plate, and diaphragm is cylindrical, the radius of the composite winding is R, the height is H, the radius of the hollow tube 2 is r, and all are in mm. 2(R+r) / (R2-r2)+2 / H=0.05.

[0036] Example 2

[0037] like Figure 5 As shown, the difference between this embodiment and embodiment 1 is that the metal shell 1 is a square column metal shell 1, the through hole 13 is circular, the hollow tube 2 is cylindrical, the radius of the hollow tube 2 is r, the side length of the shell is a, and the height is H, all in mm. 2(2a+Πr) / (a2-Πr2)+2 / H=0.07.

[0038] Example 3

[0039] like Figure 6 As shown, the difference between this embodiment and embodiment 1 is that one end of the hollow tube 2 is directly connected to the upper cover 11, and the other end is insulatedly connected to the lower cover 12 (not shown in the figure, located at the bottom of the cell), and the through hole 13 is provided on the upper cover 11.

[0040] Example 4

[0041] like Figure 7 As shown, the difference between this embodiment and embodiment 3 is that the metal casing 1 of the battery cell is square columnar.

[0042] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the initial concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A cylindrical lithium-ion cell comprising a metal can, an upper cover, a lower cover, a positive electrode sheet, a negative electrode sheet, a separator, and an electrolyte, the upper cover being connected to the positive electrode sheet, the lower cover being connected to the negative electrode sheet, characterized in that: The lower cover is directly connected to the metal shell, and a through hole is provided at the center of the lower cover. The upper cover is fixed to the metal shell through an insulating layer. The positive electrode plate, negative electrode plate, and diaphragm are wound around the hollow tube. The hollow tube is cylindrical and is directly connected to the lower cover or the upper cover, and is connected to the through hole. A support structure is provided around the end of the hollow tube. The support structure includes a first disc-shaped structure and a second disc-shaped structure. The upper cover or the lower cover is disposed between the first disc-shaped structure and the second disc-shaped structure through an insulating layer.

2. The cylindrical lithium-ion cell of claim 1, wherein, The first and second disc-shaped structures are connected, and their projections on the radial plane form a C-shaped structure.

3. The cylindrical lithium-ion cell of claim 1, wherein, One end of the hollow tube is provided with an annular bulge surrounding the axis of the cylindrical lithium-ion cell, and the annular bulge supports the upper cover.

4. The cylindrical lithium-ion cell of claim 1, wherein, The upper cover is provided with a connecting structure, which is disposed between the first disc-shaped structure and the second disc-shaped structure. The connecting structure is arranged around the hollow tube, and is insulated from the first disc-shaped structure and from the second disc-shaped structure.

5. The cylindrical lithium-ion cell of claim 4, wherein, The axial height of the connection structure combined with the first disc-shaped structure is lower than the height of the top cover.

6. The cylindrical lithium-ion cell of claim 2, wherein, The first disc-shaped structure and the second disc-shaped structure are connected and transitioned by a rounded arc.

7. The cylindrical lithium-ion cell of claim 1, wherein, The metal shell is a square column metal shell with a hollow tube radius of r, a side length of a, and a height of H, all in mm. 2(2a+Πr) / (a2-Πr2)+2 / H≥0.

05.

8. The cylindrical lithium-ion cell of claim 1, wherein, The composite winding of the positive electrode, negative electrode, and separator is cylindrical, with radius R and height H, and the radius r of the hollow tube, all in mm. 2(R+r) / (R2-r2)+2 / H≥0.

05.

9. A battery pack characterized by comprising: The invention includes a cylindrical lithium-ion battery cell as described in any one of claims 1-8, wherein a liquid cooling pipe is disposed inside the hollow tube of the cylindrical lithium-ion battery cell, and the liquid cooling pipes of adjacent cylindrical lithium-ion battery cells are interconnected.

10. A battery pack characterized by comprising: The battery pack includes a cylindrical lithium-ion cell as described in any one of claims 1-8, wherein a cooling module is provided within the battery pack, and the cooling module generates a cooling airflow that passes through the hollow tube of the cylindrical lithium-ion cell.

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