A head structure and a battery

Abstract

This utility model discloses a sealing head structure and a battery, relating to the field of battery manufacturing technology. Specifically, it includes a heat-sealing head, a heat-insulating layer, and a cold-sealing head. The heat-insulating layer is connected to one side wall of the heat-sealing head; the cold-sealing head is connected to the side wall of the heat-insulating layer away from the heat-sealing head. The heat-insulating layer blocks heat transfer between the heat-sealing head and the cold-sealing head. This application uses a heat-insulating layer between the heat-sealing head and the cold-sealing head to block heat transfer, enabling the cold-sealing head to effectively cool and protect against the spread of heat radiation, thus protecting the inner layer of the aluminum-plastic film from damage. This significantly reduces process defects caused by heat radiation and avoids cell gas expansion caused by the inability to expel gas in time. It effectively improves the formation interface, avoids defects such as black spots or lithium plating during the formation process, and is beneficial for improving battery electrical and safety performance while reducing production costs.

Description

Technical Field

[0001] This utility model relates to the field of battery manufacturing technology, and in particular to a head structure and a battery. Background Technology

[0002] Lithium-ion batteries are hailed as the "green chemical energy" of the 21st century and have been widely used in many fields such as 3C consumer electronics, power batteries, and energy storage. Compared with traditional steel-cased and aluminum-cased lithium-ion batteries, pouch lithium-ion batteries offer more flexible design, allowing for arbitrary shapes, higher energy density, and better safety. In the event of a safety issue, pouch lithium-ion batteries typically swell and crack, making them less prone to explosion. Due to their design and safety advantages, pouch batteries are continuously increasing their market share.

[0003] Soft-pack batteries achieve a sealing effect through heat sealing with an aluminum-plastic film. During heat sealing, a high-temperature sealing head is typically used to press the aluminum-plastic film together for a certain period of time. The adhesive layer of the aluminum-plastic film melts under high temperature, and the two layers of aluminum-plastic film fuse together under pressure, thus completing the heat sealing process.

[0004] However, in existing technologies, due to the thermal conductivity of aluminum-plastic film, the film near the seal is heated, causing the inner layers of the film near the seal to adhere together, typically by a distance of 2-8mm. This localized adhesion of the aluminum-plastic film caused by heat radiation can easily damage the inner layer of the PP film during later battery processing, leading to poor battery insulation, even battery leakage, resulting in significant production scrap and potential safety risks. Furthermore, pouch battery production typically includes a large gas bag to accommodate gases generated during formation. During heat sealing, the presence of heat radiation causes the gas bag volume to decrease, resulting in battery swelling during formation. This prevents timely gas release, deteriorating the formation interface and causing defects such as black spots or lithium plating, affecting battery performance and safety. Battery swelling can also lead to poor single-cell insulation, causing battery scrap. The large gas bag also results in low aluminum-plastic film utilization, wasting the film and increasing the production cost of pouch batteries.

[0005] Therefore, the end cap structure of pouch batteries needs to be optimized during the design and production process in order to improve battery performance and reduce production costs. Utility Model Content

[0006] The main purpose of this utility model is to provide a head structure and a battery, which aims to optimize the head structure, reduce the heat transfer performance of the head, and improve the yield rate in the battery manufacturing process.

[0007] To achieve the above objectives, this utility model proposes a head structure, comprising:

[0008] heat seal;

[0009] A heat insulation layer is attached to one side wall of the heat-sealed head; and

[0010] A cold-sealed head is connected to the side wall of the insulation layer away from the heat-sealed head;

[0011] The heat insulation layer blocks heat transfer between the heat-sealing head and the cold-sealing head.

[0012] In the above scheme, the preferred temperature for the heat sealing head is 180℃, and the preferred temperature for the cold sealing head is 0-5℃. The aluminum-plastic film is heat-sealed by the heat sealing head, while the cold sealing head contacts the inner side of the sealing surface to cool the edge of the aluminum-plastic film and reduce the heat radiation of the aluminum-plastic film. The heat insulation layer blocks the heat transfer between the heat sealing head and the cold sealing head, ensuring that the cold sealing head and the heat sealing head on both sides can work at different temperatures to complete the heat sealing of the battery.

[0013] Furthermore, the heat-sealing head includes an integrally formed shallow sealing portion and a deep sealing portion. The same side of the shallow and deep sealing portions forms the sealing surface. In the direction facing the sealing surface, the height of the shallow sealing portion is lower than the height of the deep sealing portion. The shallow and deep sealing portions press against different positions of the aluminum-plastic film; that is, the shallow sealing area is located near the cylinder connection, while the shallow sealing portion is in a deeper region. Together, they act on the cylinder, making the connection between the sealing head and the cylinder tighter, preventing media leakage, and ensuring the sealing reliability of the equipment.

[0014] Furthermore, the melt rate of the aluminum-plastic film on the shallow sealing portion is lower than that on the deep sealing portion. Due to the difference in height between the shallow and deep sealing portions, the heat transfer path and speed differ. An appropriate difference in melt rate ensures effective bonding between the adhesive and the material, forming a strong adhesive layer. This tightly connects the various parts of the end cap into a unified whole, enhancing the rigidity and load-bearing capacity of the end cap. While ensuring the structural strength and performance of the end cap, it optimizes the amount of adhesive used, avoiding adhesive overflow and reducing the potential impact of excessive adhesive use on the internal quality of the end cap, such as defects like porosity and inclusions.

[0015] Furthermore, the shallow sealing portion includes a first shallow sealing portion and a second shallow sealing portion distributed on both sides of the deep sealing portion, with the second shallow sealing portion connected to the heat insulation layer. This symmetrical arrangement optimizes the structure of the sealing surface, resulting in more even heating.

[0016] Furthermore, a cooling pressure head is provided at one end of the cold sealing head facing the sealing surface. The cooling pressure head contacts the inner side of the sealing surface, cooling the aluminum-plastic film at the edge of the sealing surface and reducing the heat radiation of the aluminum-plastic film.

[0017] Furthermore, the height of the cooling head is lower than that of the shallow sealing portion.

[0018] Furthermore, the heat insulation layer has a porous structure.

[0019] Furthermore, the cold sealing head is equipped with a liquid cooling device inside, which is used to reduce the temperature of the cold sealing head.

[0020] Furthermore, the liquid cooling device includes a reflux section, an inlet, and an outlet. The reflux section is located inside the cold-sealed head, and the inlet and the outlet are respectively connected to the reflux section, thus forming the liquid cooling device. The reflux section, located inside the cold-sealed head, is used to contain water or coolant. The inlet supplies water or coolant to the reflux section, and the outlet is used to discharge it, thereby achieving a circulating supply of water or coolant to ensure the temperature of the cooling head.

[0021] This application also discloses a battery that has the aforementioned end cap structure heat-sealed.

[0022] The above technical solution has the following advantages:

[0023] This application incorporates a heat insulation layer between the heat-sealing head and the cold-sealing head to block heat transfer, enabling the cold-sealing head to effectively cool and protect against the spread of heat radiation. This prevents damage to the inner layer of the aluminum-plastic film, significantly reducing process defects caused by heat radiation and improving battery production yield. Simultaneously, it maximizes the utilization of the gas bag volume advantage of the pouch battery, preventing cell expansion due to insufficient gas release during pouch cell formation. This effectively improves the formation interface, avoiding defects such as black spots or lithium plating during formation, thereby significantly enhancing the battery's electrical and safety performance. Furthermore, while achieving the aforementioned heat-blocking effect, this application can appropriately reduce the size of the pouch gas bag. This not only improves the utilization rate of the aluminum-plastic film but also further reduces the important objective of pouch battery production costs. Attached Figure Description

[0024] The present invention will now be described in detail with reference to specific embodiments and accompanying drawings, wherein:

[0025] Figure 1 This is a schematic diagram of the structure of this utility model.

[0026] In the diagram: 1. Heat sealing head; 11. Shallow sealing section one; 12. Deep sealing section; 13. Shallow sealing section two; 2. Insulation layer; 3. Cold sealing head; 31. Cooling pressure head; 4. Reflux section; 5. Liquid cooling device; 51. Inlet; 52. Outlet. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the following specific embodiments are only used to explain this utility model and do not constitute a limitation on this utility model.

[0028] like Figure 1 As shown, a sealing structure includes a heat-sealing head 1, a heat-insulating layer 2, and a cold-sealing head 3. The heat-insulating layer 2 is connected to one side wall of the heat-sealing head 1; the cold-sealing head 3 is connected to the side wall of the heat-insulating layer 2 away from the heat-sealing head 1. The heat-insulating layer 2 blocks heat transfer between the heat-sealing head 1 and the cold-sealing head 3. The heat-sealing head 1 preferably has a temperature of 180°C, and the cold-sealing head 3 preferably has a temperature of 0-5°C. The heat-sealing head 1 heat-seals the aluminum-plastic film, while the cold-sealing head 3 contacts the inner side of the sealing surface, cooling the edge of the aluminum-plastic film and reducing its heat radiation. The heat-insulating layer 2 blocks heat transfer between the heat-sealing head 1 and the cold-sealing head 3, ensuring that the cold-sealing head 3 and the heat-sealing head 1 on both sides can operate at different temperatures to complete the heat sealing of the battery.

[0029] like Figure 1 As shown, the heat-sealing head 1 includes an integrally formed shallow sealing portion and a deep sealing portion 12. The same side of the shallow sealing portion and the deep sealing portion 12 is the sealing surface. In the direction facing the sealing surface, the height of the shallow sealing portion is lower than the height of the deep sealing portion 12. The heat-sealing head 1 is formed using the shallow sealing portion and the deep sealing portion 12, which are integrally formed using a die-drawing process, greatly reducing its production cost. The shallow sealing portion and the deep sealing portion 12 press against different positions of the aluminum-plastic film; that is, the shallow sealing area is located near the cylinder connection, and the shallow sealing portion is located in a deeper area. Both work together on the cylinder, making the connection between the heat-sealing head and the cylinder tighter, preventing media leakage, and ensuring the sealing reliability of the equipment.

[0030] In the above scheme, the sealing surface is the area where the battery casing is sealed by heat sealing or other methods during the battery packaging process. For pouch batteries, the sealing surface usually refers to the heat-sealing area of ​​the aluminum-plastic film. In this application, the sealing surface of the end cap structure is the side that acts on the battery for heat sealing.

[0031] The melt rate of the aluminum-plastic film on the shallow sealing section is lower than that on the deep sealing section 12. Due to the difference in height between the shallow and deep sealing sections 12, the heat transfer path and speed differ. The temperature rises faster in areas closer to the heat source, while the temperature is relatively lower in areas farther from the heat source, resulting in temperature differences between the shallow and deep sealing areas. Therefore, an appropriate difference in melt rate can ensure effective bonding between the adhesive and the material, forming a strong adhesive layer. This tightly connects all parts of the end cap into a whole, enhancing the rigidity and load-bearing capacity of the end cap. While ensuring the structural strength and performance of the end cap, it optimizes the amount of adhesive used, avoiding adhesive overflow and reducing the potential impact of excessive adhesive use on the internal quality of the end cap, such as defects like porosity and inclusions.

[0032] like Figure 1 As shown, the shallow sealing portion includes a first shallow sealing portion 11 and a second shallow sealing portion 13 distributed on both sides of the deep sealing portion 12, and the second shallow sealing portion 13 is connected to the heat insulation layer 2. The height between the first shallow sealing portion 11 and the second shallow sealing portion 13 is preferably flush, and their symmetrical arrangement can optimize the structure of their sealing surface and make them heat-received more evenly.

[0033] like Figure 1 As shown, a cooling pressure head 31 is provided at the end of the cold sealing head 3 facing the sealing surface. The cooling pressure head 31 contacts the inner side of the sealing surface, cooling the aluminum-plastic film at the edge of the sealing surface and reducing the heat radiation of the aluminum-plastic film. Preferably, the height of the cooling pressure head 31 is lower than the shallow sealing part.

[0034] like Figure 1 As shown, the insulation layer 2 has a porous structure. This structure can dissipate the heat transferred from the heat-sealing head 1 to the cold-sealing head 3 in a timely manner, increasing the overall heat dissipation area, while also ensuring the connection strength between the cold-sealing head 3 and the heat-sealing head 1.

[0035] like Figure 1 As shown, a liquid cooling device 5 is installed inside the cold end cap 3 to reduce the temperature of the cold end cap 3. The liquid cooling device 5 uses water or coolant to cool the cold end cap 3 to ensure that its temperature is between 0-5℃.

[0036] In one embodiment of this application, the liquid cooling device 5 includes a reflux section 4, an inlet 51, and an outlet 52. The reflux section 4 is located inside the cold sealing head 3. The inlet 51 and the outlet 52 are respectively connected to the reflux section 4, so that the inlet 51, the reflux section 4, and the outlet 52 are connected to form the liquid cooling device 5. The reflux section 4, located inside the cold sealing head 3, is used to contain water or coolant. The inlet 51 provides water or coolant to the reflux section 4, and the outlet 52 is used to discharge it, thereby achieving a circulating supply of water or coolant to ensure the temperature of the cooling head.

[0037] In the above scheme, the reflux section 4 can be the cavity inside the cold sealing head 3, the reflux pipe or the water hole, which can be selected according to different needs. The inlet 51 and the outlet 52 are preferably pipe openings or water nozzles.

[0038] The liquid cooling device 5 described above can also be equipped with an independent heat dissipation structure to dissipate heat from the water or coolant in the return section 4 in a timely manner to achieve continuous circulation. This heat dissipation structure can be a semiconductor or a fan, combined with a water pump, which will not be discussed in detail here.

[0039] This application also discloses a battery with the aforementioned sealing head structure for heat sealing. This structure ensures that the aluminum-plastic film is separated during heat sealing of the pouch battery. Combined with the cold sealing head 3, it further insulates against heat, preventing the inner layers of the aluminum-plastic film near the seal from adhering together. This prevents damage to the inner PP layer of the aluminum-plastic film during later battery processing, which could lead to poor battery insulation. The heat insulation effect also prevents the gas pocket volume of the pouch battery from decreasing, thus avoiding interference with gas release during battery expansion.

[0040] The specific heat-sealing process is as follows:

[0041] When using the heat-sealing structure of this application for heat sealing, the heat sealing method is as follows: sealing pressure 0.4 MPa, sealing time 2.5 s, the PP melt rate of the aluminum-plastic film is controlled at 20±10% in the shallow sealing area and 40±10% in the deep sealing area; when using this sealing head structure to heat seal the soft pack battery, the heat sealing head 1 heat seals the aluminum-plastic film, and the cold sealing head 3 contacts the inner side of the seal to cool the aluminum-plastic film at the sealing edge and reduce the heat radiation of the aluminum-plastic film.

[0042] The fully charged battery was disassembled; the lithium intercalation at the negative electrode interface was uniform, with no lithium plating or black spots, and the interface was in good condition. The thermal radiation distance of the aluminum-plastic film was checked and found to be approximately 1-2 mm. 1000 batteries were produced, and no insulation defects were found.

[0043] Example for comparison:

[0044] A standard heat-sealing head is used for heat sealing. The heat sealing method is as follows: the temperature of heat-sealing head 1 is set to 185℃, the sealing pressure is 0.4 MPa, the sealing time is 2.5 s, and the melt rate of the aluminum-plastic film PP is controlled at 25±10%.

[0045] When the fully charged battery was disassembled, a small amount of lithium plating was found; the thermal radiation distance of the aluminum-plastic film was checked and found to be approximately 4-6 mm. Of 500 batteries produced, 5 had insulation defects, resulting in an insulation defect rate of 1.0%.

[0046] Therefore, the end cap structure of this application has a high yield rate during heat sealing.

[0047] The above description is only a preferred embodiment of the present utility model and does not limit the patent scope of the present utility model. All equivalent structural transformations made under the inventive concept of the present utility model using the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.

Claims

1. A head structure, characterized by, include: Heat-sealed head (1); A heat insulation layer (2) is connected to one side wall of the heat seal head (1); as well as A cold sealing head (3) is connected to the side wall of the insulation layer (2) away from the heat sealing head (1); The heat insulation layer (2) blocks the heat transfer between the heat sealing head (1) and the cold sealing head (3).

2. The closure structure of claim 1, wherein The heat sealing head (1) includes an integrally formed shallow sealing part and a deep sealing part (12). The same side of the shallow sealing part and the deep sealing part (12) is the sealing surface. In the direction towards the sealing surface, the height of the shallow sealing part is lower than the height of the deep sealing part (12).

3. The closure structure of claim 2, wherein The melt rate of the aluminum-plastic film on the shallow sealing part is lower than that of the aluminum-plastic film on the deep sealing part (12).

4. The closure structure of claim 2, wherein The shallow sealing portion includes a first shallow sealing portion (11) and a second shallow sealing portion (13) distributed on both sides of the deep sealing portion (12), and the second shallow sealing portion (13) is connected to the heat insulation layer (2).

5. A closure structure as claimed in claim 2 or 3 or 4, wherein, The cold sealing head (3) is provided with a cooling pressure head (31) at one end facing the sealing surface.

6. The closure structure of claim 5, wherein The height of the cooling head (31) is lower than that of the shallow seal.

7. The closure structure of claim 1, wherein The heat insulation layer (2) has a porous structure.

8. The head structure as described in claim 1, characterized in that, The cold sealing head (3) is equipped with a liquid cooling device (5) inside, which is used to reduce the temperature of the cold sealing head (3).

9. The closure structure of claim 8, wherein, The liquid cooling device (5) includes a reflux section (4), an inlet (51), and an outlet (52). The reflux section (4) is located inside the cold sealing head (3). The inlet (51) and the outlet (52) are respectively connected to the reflux section (4), so that the inlet (51), the reflux section (4), and the outlet (52) are connected to form the liquid cooling device (5).

10. A battery, characterized by The battery heat seal has a cap structure as described in any one of claims 1 to 9.

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