A hard-shell lithium-ion cell and battery pack

Abstract

This utility model discloses a hard-shell lithium-ion battery cell and battery pack. The hard-shell lithium-ion battery cell includes a shell, a cover plate, a cell winding body, and an electrolyte. The cell winding body and the electrolyte are disposed inside the shell. A positive terminal and a negative terminal are disposed on the cover plate, and the positive terminal and the negative terminal are insulated from the cover plate. The positive terminal of the cell winding body is connected to the positive terminal, and the negative terminal of the cell winding body is connected to the negative terminal. By setting through grooves around the cell winding body and adopting an arc connection structure, the heat exchange area between the cell and the outside is significantly increased, so that heat can be conducted from the inside of the cell to the outside more quickly, thereby effectively reducing the temperature of the cell during operation and reducing heat accumulation.

Description

Technical Field

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

[0002] In today's power battery and energy storage field, hard-shell lithium-ion cells stand out due to their superior performance. Their significantly high energy density means that more electrical energy can be stored within limited volume or weight constraints, providing stronger and longer-lasting power. Furthermore, hard-shell lithium-ion cells have a long cycle life, capable of withstanding multiple charge-discharge cycles, which not only significantly extends the cell's lifespan but also effectively reduces equipment maintenance and replacement costs. Their low self-discharge rate ensures minimal energy loss during long-term storage, maintaining sufficient charge and keeping the cells in optimal, readily available condition.

[0003] However, hard-shell lithium-ion cells face severe thermal management challenges in practical applications. First, during operation, the cells generate a significant amount of heat, which tends to accumulate inside and is difficult to dissipate quickly. When this heat buildup reaches a certain level, it can cause a rapid rise in cell temperature, potentially leading to thermal runaway and posing a significant threat to safety. Second, in practical applications, battery packs are typically composed of numerous individual hard-shell lithium-ion cells. This structure can easily result in uneven temperature distribution among the cells, causing the battery to lose performance prematurely and potentially leading to various serious safety issues. Therefore, implementing reasonable and effective thermal management for battery packs is crucial.

[0004] To effectively improve the heat dissipation efficiency of hard-shell lithium-ion cells, a common practice is to use cooling pipes that can fully contact the cell casing and exchange heat with it. In particular, to maximize the heat exchange area between the cooling pipes and the cell, flat cooling pipes or heat pipes are often specifically chosen. This approach does indeed improve the heat exchange capacity of the battery pack to some extent. However, due to the limitations of the surface area and heat transfer capacity of the hard-shell lithium-ion cells themselves, even with these measures, the battery pack still suffers from low heat exchange efficiency and uneven temperature distribution. Utility Model Content

[0005] This utility model discloses a hard-shell lithium-ion battery cell, including a shell, a cover plate, a battery cell winding body, and an electrolyte. The battery cell winding body and the electrolyte are disposed inside the shell. A positive electrode post and a negative electrode post are disposed on the cover plate, and the positive and negative electrode posts are insulated from the cover plate. The positive electrode of the battery cell winding body is connected to the positive electrode post, and the negative electrode of the battery cell winding body is connected to the negative electrode post. It also includes a through slot, with two opposite surfaces of the through slot connected by an arc. The battery cell winding body is disposed around the through slot. One edge of the through slot is connected to the cover plate, and the other edge of the through slot is connected to the bottom surface of the shell. The shell has a length of a, a width of b, and a height of H. The arc diameter of the through slot is c, and the length is d. a, b, c, d, and H are all in mm and satisfy the following condition: 0.2 ≥ 4(2a + 2b + 2d + Πc) / (4ab - Πc). 2 -4cd)+2 / H≥0.05. Optionally, the ratio of the width of the cell winding to the width of the slot is selected from 7.5 to 9.0.

[0006] By incorporating through-slots around the cell winding and employing an arc-shaped connection, the heat exchange area between the cell and the external environment is significantly increased. This design allows heat to be conducted more quickly from the inside of the cell to the outside, effectively reducing the cell's operating temperature and minimizing heat buildup. Furthermore, the arc-shaped connection of the through-slots optimizes the contact area between the through-slots and the cell winding compared to right-angle connections, providing more heat conduction paths and further improving heat exchange efficiency. This design allows heat to dissipate more rapidly from the inside of the cell, thereby better controlling the cell's operating temperature and reducing the risk of thermal runaway.

[0007] Furthermore, the through-slot structure effectively disperses stress concentration, significantly improving the overall strength of the cell structure. Especially during cell operation, the mechanical and thermal stresses caused by charging and discharging extend the cell's lifespan.

[0008] The ratio of the cell winding width to the slot width is selected from 7.5 to 9.0. This optimized ratio further improves heat dissipation efficiency. The ratio of the cell winding width to the slot width is precisely calculated to meet specific geometric conditions and ensure optimal heat dissipation performance. For example, when the ratio is less than 7.5, the slot width is larger, and the area inside the cell closer to the slot dissipates heat faster, while the area farther from the slot dissipates heat slower, resulting in a larger temperature difference. When the ratio is greater than 9.0, the slot width is smaller, resulting in insufficient heat dissipation capacity, and the heat inside the cell is difficult to distribute evenly, which also leads to a larger temperature difference.

[0009] Preferably, the positive electrode post includes an outer connecting block and an inner connecting block, the outer connecting block and the inner connecting block are electrically connected, a first insulating elastic layer is provided between the outer connecting block and the cover plate, a second insulating elastic layer and an insulating plate are provided between the inner connecting block and the cover plate, and the insulating plate extends along the cover plate to the negative electrode post and makes the negative electrode post insulated from the cover plate.

[0010] The first and second insulating elastic layers are respectively disposed between the outer connecting block and the cover plate, and between the inner connecting block and the cover plate, further enhancing the insulation performance between the positive electrode post and the cover plate, preventing electrical connection between the positive electrode post and the cover plate, thereby avoiding short circuits. By setting an insulating elastic layer between the positive electrode post and the cover plate, the potential difference between the positive electrode post and the cover plate can be effectively reduced, reducing electrochemical corrosion and helping to improve the reliability and service life of the battery cell.

[0011] Preferably, the first insulating elastic layer extends to the four peripheral surfaces of the outer connecting block, and the height of the first insulating layer surrounding the four peripheral surfaces of the outer connecting block is 10% to 90% of the height of the outer connecting block. Setting the height of the first insulating layer to 10% to 90% of the height of the outer connecting block, preferably 50% to 90%, is a precisely calculated ratio that provides sufficient insulation protection without affecting the overall structural compactness and assembly efficiency of the battery cell due to excessive insulation layer height.

[0012] Preferably, the through groove and the shell satisfy the following condition: 4(2a+2b+2d+Πc) / (4ab-Πc) 2 -4cd) +2 / H≥0.1. This design is more conducive to the operation of power batteries, significantly increasing the contact area between the cell and the external environment, thereby improving heat dissipation efficiency.

[0013] Preferably, the insulating plate has a through-hole for the slot to pass through, and the insulating plate extends to the side of the inner connecting block, with the height of the insulating plate on the side equal to the height of the inner connecting block. The extension of the insulating plate to the side of the inner connecting block and its matching height ensure complete electrical isolation between the positive and negative terminals. By providing the through-hole, the insulating plate effectively isolates the slot from other components of the battery cell, preventing arc discharge around the slot and thus improving the battery's safety and reliability.

[0014] Preferably, an axially extending protrusion is provided on the plane of the through slot. The protrusion is located in the middle region of the through slot along its axial direction, and its axial length is set to 75% to 90% of the housing height. The presence of the protrusion significantly increases the contact area between the through slot and the external environment, thereby improving heat dissipation efficiency. Located in the middle region of the through slot, the protrusion guides heat to be evenly distributed along its axial direction, helping to reduce the temperature gradient inside the cell, further optimizing the heat dissipation path, and reducing localized overheating. By rationally setting the length and position of the protrusion, the heat generated inside the cell can be more effectively conducted to the outside, preventing heat accumulation.

[0015] Preferably, the radial length of the convex ridge is set to 35% to 45% of the arc diameter of the through groove. If the radial length of the convex ridge is too long (exceeding 45% of the arc diameter of the through groove), it may occupy too much space in the through groove, narrowing the heat dissipation channel and reducing the airflow through the through groove, thus reducing the heat dissipation efficiency of the through groove. If the through groove is used for coolant flow, a shorter convex ridge may not effectively guide the coolant to flow uniformly along the axial direction of the through groove, resulting in uneven coolant flow, which will reduce the heat dissipation efficiency of the coolant. If the through groove is used for cooling airflow, a shorter convex ridge may generate more turbulence within the through groove, increasing the flow resistance of the coolant and reducing the flow efficiency of the coolant.

[0016] This utility model also describes a battery pack composed of several hard-shell lithium-ion cells, wherein liquid cooling pipes are provided in the through slots of the hard-shell lithium-ion cells, and the liquid cooling pipes of adjacent hard-shell lithium-ion cells are interconnected.

[0017] This utility model also describes a battery pack composed of several hard-shell lithium-ion cells. The battery pack is equipped with an air-cooling module, which generates cooling airflow that passes through the through slots of the hard-shell lithium-ion cells. Attached Figure Description

[0018] Figure 1 This is a perspective view of a hard-shell lithium-ion battery cell disclosed in this utility model;

[0019] Figure 2 This is a top view of a hard-shell lithium-ion battery cell disclosed in this utility model;

[0020] Figure 3 This is a bottom view of a hard-shell lithium-ion battery cell disclosed in this utility model;

[0021] Figure 4 This is a three-dimensional cross-sectional view of a hard-shell lithium-ion battery cell disclosed in this utility model;

[0022] Figure 5 This is a cross-sectional view of the electrode portion of a hard-shell lithium-ion battery cell disclosed in this utility model;

[0023] Figure 6 This is a top view of another type of hard-shell lithium-ion battery cell disclosed in this utility model;

[0024] Among them, 1. shell, 11. bottom surface, 2. cover plate, 21. positive electrode post, 211. outer connecting block, 212. inner connecting block, 213. first insulating elastic layer, 214. second insulating elastic layer, 215. insulating plate, 22. negative electrode post, 3. through groove, 31. arc, 32. protruding ridge. Detailed Implementation

[0025] 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.

[0026] Example 1

[0027] like Figure 1-4 As shown, this embodiment relates to a hard-shell lithium-ion battery cell, the structure of which includes a shell 1, a cover plate 2, a battery cell winding body (not shown in the figure), and an electrolyte. The battery cell winding body and the electrolyte are disposed inside the shell 1, while the cover plate 2 is provided with a positive electrode post 21 and a negative electrode post 22, both of which are insulated from the cover plate 2. The positive and negative electrodes of the battery cell winding body are connected to the positive electrode post 21 and the negative electrode post 22, respectively. In addition, the battery cell also includes a through groove 3, the two opposite surfaces of which are connected by an arc 31, and the battery cell winding body is arranged around the through groove 3. One end of the through groove 3 is connected to the cover plate 2, and the other end is connected to the bottom surface 11 of the shell 1.

[0028] The ratio of the width of the battery cell winding to the width of the through slot 3 is 7.5. This ratio has been precisely calculated to significantly improve heat dissipation efficiency and ensure optimal heat dissipation performance. The length of the shell 1 is a, the width is b, and the height is H. The diameter of the arc 31 of the through slot 3 is c, and the length is d. Where a, b, c, d, and H are all in millimeters and satisfy the following condition: 4(2a+2b+2d+πc) / (4ab-πc²-4cd)+2 / H=0.07.

[0029] By setting through slots 3 around the battery cell winding and connecting them with arcs 31, the heat exchange area between the battery cell and the outside environment is significantly increased. The positive electrode post 21 consists of an outer connecting block 211 and an inner connecting block 212, which are electrically connected. A first insulating elastic layer 213 is provided between the outer connecting block 211 and the cover plate 2, while a second insulating elastic layer 214 and an insulating plate 215 are provided between the inner connecting block 212 and the cover plate 2. The insulating plate 215 extends along the cover plate 2 to the negative electrode post 22, ensuring that the negative electrode post 22 and the cover plate 2 remain insulated. The first insulating elastic layer 213 extends to the four peripheral edges of the outer connecting block 211, and its height is 50% of the height of the outer connecting block 211. This design further enhances the insulation performance between the positive electrode post 21 and the cover plate 2, prevents short circuits, reduces potential difference, reduces electrochemical corrosion, and helps improve the reliability and service life of the battery cell.

[0030] Example 2

[0031] The difference from Example 1 is that the hard-shell lithium-ion cell in this example is a power-type cell with a high charge / discharge rate, resulting in higher heat generation. The through-slot 3 and the casing 1 satisfy the following condition: 4(2a+2b+2d+Πc) / (4ab-Πc²-4cd)+2 / H=0.2. This design is more conducive to the operation of power-type batteries, significantly increasing the contact area between the cell and the external environment, thereby improving heat dissipation efficiency.

[0032] Example 3

[0033] like Figure 5 As shown, the difference from Embodiment 1 is that an axially extending protrusion 32 is provided on the plane of the through groove 3. The protrusion 32 is located in the middle region of the through groove 3 in the axial direction. The axial length of the protrusion 32 is set to 75% of the height of the housing 1, and the radial length of the protrusion 32 is set to 35% of the diameter of the arc 31 of the through groove 3. This significantly increases the contact area between the through groove 3 and the external environment, reduces local overheating, and avoids heat accumulation.

[0034] 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 hard-shell lithium-ion battery cell, comprising a shell, a cover plate, a cell winding body, and an electrolyte, wherein the cell winding body and the electrolyte are disposed within the shell, a positive electrode post and a negative electrode post are disposed on the cover plate, the positive electrode post and the negative electrode post are insulated from the cover plate, the positive electrode of the cell winding body is connected to the positive electrode post, and the negative electrode of the cell winding body is connected to the negative electrode post, characterized in that: It also includes a through slot, the two opposite sides of which are connected by an arc. The battery cell winding body is arranged around the through slot. One edge of the through slot is connected to the cover plate, and the other edge of the through slot is connected to the bottom surface of the housing. The length of the housing is a, the width is b, and the height is H. The arc diameter of the through slot is c, and the length is d. a, b, c, d, and H are all in mm and satisfy the following condition: 0.2 ≥ 4(2a + 2b + 2d + Πc) / (4ab - Πc) 2 -4cd)+2 / H≥0.

05.

2. The hard-shell lithium-ion battery cell according to claim 1, characterized in that, The positive electrode post includes an outer connecting block and an inner connecting block, the outer connecting block and the inner connecting block are electrically connected, a first insulating elastic layer is provided between the outer connecting block and the cover plate, a second insulating elastic layer and an insulating plate are provided between the inner connecting block and the cover plate, and the insulating plate extends along the cover plate to the negative electrode post and makes the negative electrode post insulated from the cover plate.

3. The hard-shell lithium-ion battery cell according to claim 2, characterized in that, The first insulating elastic layer extends to the four peripheral surfaces of the outer connecting block, and the height of the first insulating layer surrounding the four peripheral surfaces of the outer connecting block is 10% to 90% of the height of the outer connecting block.

4. The hard-shell lithium-ion battery cell according to claim 1, characterized in that, The ratio of the width of the cell winding to the width of the slot is selected from 7.5 to 9.0, and the slot and the housing satisfy the following condition: 4(2a+2b+2d+Πc) / (4ab-Πc) 2 -4cd)+2 / H≥0.

1.

5. The hard-shell lithium-ion battery cell according to claim 2, characterized in that, The insulating plate has a through-hole with a slot, and the insulating plate extends to the side of the inner connecting block. The height of the insulating plate on the side is equal to the height of the inner connecting block.

6. The hard-shell lithium-ion cell according to claim 1, characterized in that, An axially extending ridge is provided on the plane of the through groove. The ridge is located in the middle region of the through groove in the axial direction, and the axial length of the ridge is set to 75% to 90% of the height of the housing.

7. The hard-shell lithium-ion cell according to claim 6, characterized in that, The radial length of the protruding ridge is set to 35% to 45% of the arc diameter of the through groove.

8. A battery pack, characterized in that, The hard-shell lithium-ion battery cell as described in any one of claims 1-5 is provided with a liquid cooling pipe in the through slot of the hard-shell lithium-ion battery cell, and the liquid cooling pipes of adjacent hard-shell lithium-ion battery cells are interconnected.

9. A battery pack, characterized in that, Includes a hard-shell lithium-ion cell as described in any one of claims 1-7, wherein a cooling module is provided within the battery pack, and the cooling module generates a cooling airflow that passes through the through-slot of the hard-shell lithium-ion cell.

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