Sealant, sealing assembly, battery cell, and electric device
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2025-02-06
- Publication Date
- 2026-08-13
Smart Images
Figure CN2025075969_13082026_PF_FP_ABST
Abstract
Description
Sealants, sealing components, battery cells and electrical equipment Technical Field
[0001] This application relates to the field of energy storage technology, and in particular to a sealant, sealing assembly, battery cell, and electrical equipment. Background Technology
[0002] With the continuous updating and development of lithium-ion battery technology, the application fields of lithium-ion batteries are also expanding. As a result, the safety of battery cells is receiving increasing public attention. Lithium-ion battery safety accidents characterized by thermal runaway caused by external short circuits occur frequently, which poses a certain obstacle to the development of lithium-ion batteries. How to solve the problem of battery cell safety is a difficult problem that the lithium-ion battery industry cannot avoid. Summary of the Invention
[0003] In view of this, it is necessary to provide a sealant, sealing components, battery cells, and electrical equipment to improve safety.
[0004] Embodiments of this application provide a sealant comprising a first material and a second material mixed together. The first material has a first melting point, and the second material has a second melting point. The range of the first melting point A is 50℃ ≤ A ≤ 120℃, and the range of the second melting point B is 120℃ < B ≤ 170℃. By setting multiple melting point ranges, the sealant can melt within the temperature range of the first and second melting points, effectively controlling the melting and pressure relief point of the sealant. It can begin to melt and soften at a lower temperature, which is beneficial for quickly forming pressure relief channels at high temperatures. The sealant still retains a certain strength, improving the heat dissipation efficiency and safety performance of the battery cell.
[0005] In one or more of the above optional embodiments, the range of the first melting point A is 50℃≤A≤100℃, and / or the range of the second melting point B is 140℃≤B≤170℃, which further facilitates the rapid formation of a pressure relief channel at high temperatures, thereby improving the heat dissipation efficiency and safety performance of the battery cell.
[0006] In one or more of the above optional embodiments, the melt flow index of the sealant at 230°C and a load of 2.16 kg is 4 g / 10 min to 20 g / 10 min. If the melt flow index of the sealant is less than 4 g / 10 min, the fluidity of the sealant after melting is low, affecting the formation of a rapid pressure relief channel, reducing heat dissipation efficiency, and hindering the improvement of the cell's safety performance. If the melt flow index of the sealant is greater than 20 g / 10 min, the fluidity of the sealant after melting is too high, affecting the cell's sealing performance and easily leading to cell leakage. By limiting the melt flow index of the sealant at 230°C and a load of 2.16 kg to 4 g / 10 min to 20 g / 10 min, the cell's sealing performance is improved, which is conducive to the rapid formation of a pressure relief channel, improving the cell's heat dissipation efficiency, and thus improving the cell's safety performance.
[0007] In one or more of the above optional embodiments, the melt flow index of the sealant at 230°C and a load of 2.16 kg is 6 g / 10 min to 14 g / 10 min. This facilitates the rapid formation of pressure relief channels in the battery cell at high temperatures, improving the heat dissipation efficiency of the battery cell; it further improves the sealing performance of the battery cell under extreme operating conditions, thereby enhancing the safety performance of the battery cell.
[0008] In one or more of the above optional embodiments, the melt index of the sealant at 230°C and a load of 2.16 kg is 7.1 g / 10 min to 12 g / 10 min. This further facilitates the rapid formation of pressure relief channels in the battery cell at high temperatures, improving the heat dissipation efficiency of the battery cell; it also further improves the sealing performance of the battery cell under extreme operating conditions, thereby enhancing the safety performance of the battery cell.
[0009] In one or more of the above optional embodiments, the difference between the first melting point and the second melting point is 20℃-80℃. If the difference between the first melting point and the second melting point is less than 20℃ or greater than 80℃, the sealant is prone to premature melting, causing leakage of the battery cell, affecting the battery cell's lifespan, or increasing the formation time of the pressure relief channel, reducing the battery cell's heat dissipation efficiency. A difference that is too low or too high cannot simultaneously satisfy the requirements of rapid pressure relief and safety performance of the battery cell. By limiting the difference between the first melting point and the second melting point to 20℃-80℃, it is beneficial to quickly form a pressure relief channel, realize battery cell pressure relief, and improve the battery cell's heat dissipation efficiency and safety performance.
[0010] In one or more of the above optional embodiments, the difference between the first melting point and the second melting point is 40℃-60℃. This further facilitates the rapid formation of a pressure relief channel, allowing the battery cell to release pressure and improving the cell's heat dissipation efficiency and safety performance.
[0011] In one or more of the above optional embodiments, the sealant has a first degree of crystallinity and a second degree of crystallinity, wherein the first degree of crystallinity is 1%-30% and the second degree of crystallinity is 0.01%-5%. If the first degree of crystallinity is less than 1% and the second degree of crystallinity is less than 0.01%, the sealant has excessively high fluidity after melting, resulting in low strength and affecting the sealing performance of the battery cell, which can easily lead to leakage. If the first degree of crystallinity is greater than 30% and the second degree of crystallinity is greater than 5%, the sealant has low fluidity after melting, affecting the formation of rapid pressure relief channels, reducing heat dissipation efficiency, and hindering the improvement of battery cell safety performance. By limiting the first degree of crystallinity to 1%-30% and the second degree of crystallinity to 0.01%-5%, it is beneficial to control the melting of the sealant within the temperature range of the first and second melting points, effectively regulating the melting pressure relief point of the sealant, facilitating the rapid formation of pressure relief channels in the battery cell, improving heat dissipation efficiency and safety performance, and ensuring the sealing reliability of the sealant.
[0012] In one or more of the above optional embodiments, the total crystallinity of the sealant is 2%-35%. If the crystallinity of the sealant is less than 2%, the fluidity after melting is too high, affecting the sealing performance of the battery cell and easily leading to leakage. If the crystallinity of the sealant is greater than 35%, the fluidity after melting is low, affecting the formation of rapid pressure relief channels, reducing heat dissipation efficiency, and hindering the improvement of the battery cell's safety performance. By limiting the total crystallinity of the sealant to 2%-35%, it is beneficial to control the melting of the sealant within the temperature range of the first melting point and the second melting point, effectively regulating the melting pressure relief point of the sealant, which is conducive to the rapid formation of pressure relief channels in the battery cell, improving heat dissipation efficiency and safety performance, and achieving reliable sealing of the sealant.
[0013] In one or more of the above optional embodiments, the number average molecular weight of the sealant is Mn, and the weight average molecular weight of the sealant is Mw, and at least one of the following conditions is met: Mn is 10000g / mol-130000g / mol. If the number average molecular weight of the sealant is less than 10000g / mol, the melt viscosity of the sealant is low, which is not conducive to processing and molding, and easily leads to high fluidity of the sealant after melting, reducing the encapsulation reliability of the battery cell under normal temperature conditions. If the number average molecular weight of the sealant is greater than 130000g / mol, the melt viscosity of the sealant is high, which is not conducive to processing and molding, and easily leads to low fluidity of the sealant, affecting the formation of rapid pressure relief channels, reducing heat dissipation efficiency, and reducing the safety performance of the battery cell. By limiting the number-average molecular weight (Mn) of the sealant to 10,000 g / mol-130,000 g / mol, the encapsulation reliability of the battery cell under normal temperature conditions and the mechanical strength of the sealant are improved; the weight-average molecular weight (Mw) is limited to 100,000 g / mol-800,000 g / mol. If the weight-average molecular weight of the sealant is less than 100,000 g / mol, the mechanical strength of the sealant is low; if the weight-average molecular weight of the sealant is greater than 800,000 g / mol, the melt viscosity of the sealant is high and it is not easy to flow. By limiting the weight-average molecular weight (Mw) of the sealant to 100,000 g / mol-800,000 g / mol, the encapsulation reliability of the battery cell under normal temperature conditions and the mechanical strength of the sealant are improved; the Mw / Mn ratio is 3-10, which improves the polydispersity index of the material, broadens the melting point range (melting range) of the sealant, and allows for adjustment of the melt index, which is beneficial for increasing the material's fluidity at high temperatures, allowing it to melt rapidly after reaching the melting point. The sealant structure collapses to form pressure relief channels, improving the heat dissipation efficiency of the battery cell.
[0014] In one or more of the above optional embodiments, the sealant has a first material and a second material, which at least satisfy one of the following conditions: the first material accounts for 30-90%, the second material accounts for 10-70%, the first material has a first melting point, and the second material has a second melting point. The first material melts rapidly at high temperatures to relieve pressure, while the second material provides structural strength under extreme operating conditions. The number-average molecular weight (Mn) of the first material is 10,000 g / mol to 130,000 g / mol, and the weight-average molecular weight (Mw) is 100,000 g / mol to 400,000 g / mol. If the number-average molecular weight (Mn) of the first material is less than 10,000 g / mol, and the weight-average molecular weight (Mw) is less than 100,000 g / mol, the melt viscosity is too low, which is not conducive to processing and molding, and easily leads to high fluidity of the sealant after melting, reducing the encapsulation reliability of the battery cell under normal operating conditions. If the number-average molecular weight of the first material is greater than 130,000 g / mol, and the weight-average molecular weight (Mw) is greater than 400,000 g / mol, the melt viscosity is high, which is not conducive to processing and molding, and easily leads to low fluidity of the sealant, affecting the formation of rapid pressure relief channels, reducing heat dissipation efficiency, and reducing the safety performance of the battery cell. By limiting the number-average molecular weight (Mn) of the first material to 10,000 g / mol-130,000 g / mol and the weight-average molecular weight (Mw) to 100,000 g / mol-400,000 g / mol, it is easier to process and mold, which facilitates the rapid formation of pressure relief channels in the battery cell, improves heat dissipation efficiency and safety performance, and ensures the sealing reliability of the sealant; the number-average molecular weight (Mn) of the second material is 50,000 g / mol-130,000 g / mol and the weight-average molecular weight (Mw) is 200,000 g / mol-60,000 g / mol. If the number-average molecular weight (Mn) of the second material is less than 50,000 g / mol and the weight-average molecular weight (Mw) is less than 200,000 g / mol, the structural strength of the sealant is likely to be low, reducing the encapsulation reliability of the battery cell under normal temperature conditions. If the number-average molecular weight of the first material is greater than 130,000 g / mol and the weight-average molecular weight (Mw) of the second material is greater than 600,000 g / mol, the melt viscosity is high, which is not conducive to processing and molding, and the polymer is prone to uneven dispersion, affecting the sealing and pressure relief performance of the sealant. By limiting the number-average molecular weight (Mn) of the second material to 50,000 g / mol-130,000 g / mol and the weight-average molecular weight (Mw) to 200,000 g / mol-600,000 g / mol, processing and molding are facilitated, which is conducive to the rapid formation of pressure relief channels in the battery cell, improving heat dissipation efficiency and safety performance, and ensuring the sealing reliability of the sealant.
[0015] In one or more of the above optional embodiments, the sealant material includes at least one of polyolefin resin, acid-modified polyolefin resin, polyethylene, polypropylene, ethylene elastomer and styrene elastomer.
[0016] Embodiments of this application provide a sealing assembly, including a connector, a fastener, and a sealant as described in any of the above embodiments, wherein the sealant is located between the connector and the fastener.
[0017] In one or more of the above optional embodiments, the fastener has a first opening, and a portion of the sealant is embedded in the first opening, which helps to improve the sealing performance of the battery cell.
[0018] In one or more of the above optional embodiments, the outer diameter of the fastener is larger than the outer diameter of the sealant. Along the thickness direction of the sealing assembly, the sealant is located inside the fastener, and the portion of the fastener extending beyond the sealant facilitates the provision of pre-drilled solder marks for welding the fastener to the housing.
[0019] In one or more of the above optional embodiments, the outer diameter of the fastener is larger than the outer diameter of the connector. Along the thickness direction of the sealing assembly, the connector is located inside the fastener, which facilitates pre-reserved welding positions for welding the fastener to the housing. The outer diameter of the connector is smaller than the outer diameter of the sealant, which helps to improve the pressure relief function of the sealant.
[0020] In one or more of the above optional embodiments, the bonding area between the sealant and the fastener is S, 2mm. 2 ≤S≤10mm 2 This helps the sealant to seal the first opening and facilitates the rapid formation of a pressure relief channel during pressure release, thereby improving the heat dissipation efficiency and safety performance of the battery cell.
[0021] An embodiment of this application provides a battery cell, including a housing and a sealing assembly as described in any of the above embodiments, wherein the housing has a second opening and the sealing assembly covers the second opening.
[0022] In one or more of the above optional embodiments, the fastener connects to the housing, and along the thickness direction of the sealant, the first opening and the second opening overlap, and the sealant covers the second opening and the first opening, thereby improving the sealing performance of the battery cell.
[0023] In one or more of the above optional embodiments, the battery cell satisfies at least one of the following conditions: the diameter of the first opening is d1, 0.1mm≤d1≤4mm, so that the fixing member has a sufficient effective connection width, improves the reliability of the connection between the fixing member and the housing, and reduces the risk of the fixing member blocking the pressure relief of the second opening; the diameter of the second opening is d2, 0.5mm≤d2≤5.5mm, so that the second opening has better heat dissipation efficiency and reduces the sealing problem between the sealing component and the second opening; the diameter of the second opening is larger than the diameter of the first opening, which is beneficial to improving the heat dissipation efficiency of the battery cell.
[0024] Embodiments of this application provide an electrical device including the battery cell from any of the above embodiments. Attached Figure Description
[0025] Figure 1 shows an exploded schematic diagram of the battery cell in some embodiments.
[0026] Figure 2 shows a schematic diagram of the structure of the electrical equipment in some embodiments.
[0027] Key component symbols: Sealant 100, Sealing assembly 200, Connector 210, Fixing component 220, First opening 221, Battery cell 300, Housing 310, Second opening 311, Electrode assembly 320, Terminal post 330, Electrical equipment 400
[0028] The following specific embodiments will further illustrate this application in conjunction with the above-described accompanying drawings. Detailed Implementation
[0029] The following specific embodiments are exemplary and not limiting, and are intended to provide a basic understanding of this application, and are not intended to identify key or decisive elements of this application or limit the scope of protection. As long as there is no structural conflict, the technical features mentioned in the various embodiments can be combined in any manner.
[0030] When a component is considered to be "located" on another component, it can be directly on the other component or may also be interspersed with other components. When a component is considered to be "connected" to another component, it can be directly connected to the other component or may also be interspersed with other components.
[0031] Unless otherwise defined, the term "multiple" in this document, when used to describe the number of components, specifically means that the component is two or more.
[0032] Some embodiments of this application will now be described with reference to the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.
[0033] Referring to Figure 1, this application provides a sealant 100, which comprises a first material and a second material mixed together. The first material has a first melting point, and the second material has a second melting point. The range of the first melting point A is 50℃≤A≤120℃, and / or the range of the second melting point B is 120℃<B≤170℃. By setting multiple melting point ranges, the sealant 100 can melt within the temperature range of the first and second melting points, effectively controlling the melting and pressure relief point of the sealant 100. It can begin to melt and soften at a lower temperature, which is beneficial for quickly forming a pressure relief channel at high temperatures. The sealant 100 still has a certain strength, improving the heat dissipation efficiency and safety performance of the battery cell 300.
[0034] Optionally, the first melting point can be any one or any combination of two of the following: 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, and 120°C.
[0035] Optionally, the second melting point can be any one or any combination of two of the following: 120.1°C, 121°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, 155°C, 160°C, 165°C, and 170°C.
[0036] In some embodiments, the range of the first melting point A is 50℃≤A≤100℃, and / or the range of the second melting point B is 140℃≤B≤170℃, which further facilitates the rapid formation of a pressure relief channel at high temperatures and improves the heat dissipation efficiency and safety performance of the battery cell 300.
[0037] In some embodiments, the difference between the first melting point and the second melting point is 20℃-80℃. A difference that is too low or too high cannot simultaneously satisfy the requirements for rapid pressure relief and safety performance of the battery cell. If the difference between the first melting point and the second melting point is less than 20℃ or greater than 80℃, the sealant 100 may melt prematurely, causing leakage from the battery cell, affecting the lifespan of the battery cell 300, or increasing the formation time of the pressure relief channel, thus reducing the heat dissipation efficiency of the battery cell 300. By limiting the difference between the first melting point and the second melting point to 20℃-80℃, it is beneficial to quickly form a pressure relief channel, achieve pressure relief of the battery cell 300, and improve the heat dissipation efficiency and safety performance of the battery cell 300.
[0038] Optionally, the difference between the first melting point and the second melting point can be any one or any two of the following: 20℃, 25℃, 30℃, 35℃, 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, and 80℃.
[0039] In some embodiments, the difference between the first melting point and the second melting point is 40°C-60°C, which further facilitates the rapid formation of a pressure relief channel, allowing the battery cell 300 to release pressure and improving the heat dissipation efficiency and safety performance of the battery cell 300.
[0040] In some embodiments, the sealant 100 has a third melting point, the range of which is the same as the range of the second melting point. When the melting point value of the third melting point is greater than that of the second melting point, it is more beneficial to improve the hardness of the sealant 100 and facilitate the improvement of process yield.
[0041] In some embodiments, the melt flow index of sealant 100 at 230°C and a load of 2.16 kg is 4 g / 10 min to 20 g / 10 min. If the melt flow index of sealant 100 is less than 4 g / 10 min, the fluidity of sealant 100 after melting is low, affecting the formation of a rapid pressure relief channel, reducing heat dissipation efficiency, and hindering the improvement of the safety performance of cell 300. If the melt flow index of sealant 100 is greater than 20 g / 10 min, the fluidity of sealant 100 after melting is high, affecting the sealing performance of cell 300 under extreme operating conditions, and easily leading to leakage of cell 300. By limiting the melt flow index of sealant 100 at 230°C and a load of 2.16 kg to 4 g / 10 min to 20 g / 10 min, the sealing performance of cell 300 is improved, which is conducive to the rapid formation of a pressure relief channel at high temperatures, improving the heat dissipation efficiency of cell 300, and thus improving the safety performance of cell 300.
[0042] Optionally, the melt index of sealant 100 at 230°C and 2.16 kg load can be any one or any combination of two of the following: 4 g / 10 min, 5 g / 10 min, 6 g / 10 min, 7 g / 10 min, 8 g / 10 min, 9 g / 10 min, 10 g / 10 min, 11 g / 10 min, 12 g / 10 min, 13 g / 10 min, 14 g / 10 min, 15 g / 10 min, 16 g / 10 min, 17 g / 10 min, 18 g / 10 min, 19 g / 10 min, and 20 g / 10 min.
[0043] In some embodiments, the melt flow index of sealant 100 at 230°C and 2.16kg load is 6g / 10min-14g / 10min, which is beneficial for the cell 300 to quickly form a pressure relief channel at high temperature, thereby improving the heat dissipation efficiency of the cell 300; further improving the sealing performance of the cell 300 under extreme operating conditions, and thus improving the safety performance of the cell 300.
[0044] In some embodiments, the melt index of sealant 100 at 230°C and 2.16kg load is 7.1g / 10min-12g / 10min, which further facilitates the rapid formation of pressure relief channels in cell 300 at high temperatures, improves the heat dissipation efficiency of cell 300, further improves the sealing performance of cell 300 under extreme operating conditions, and thus improves the safety performance of cell 300.
[0045] In some embodiments, the sealant 100 includes a first crystallinity and a second crystallinity, wherein the first crystallinity is 1%-30% and the second crystallinity is 0.01%-5%. If the first crystallinity is less than 1% and the second crystallinity is less than 0.01%, the sealant 100 has excessively high fluidity after melting, resulting in low strength and affecting the sealing performance of the battery cell 300, potentially leading to leakage. If the first crystallinity is greater than 30% and the second crystallinity is greater than 5%, the sealant 100 has low fluidity after melting, affecting the formation of rapid pressure relief channels, reducing heat dissipation efficiency, and negatively impacting the safety performance of the battery cell 300. By limiting the first crystallinity to 1%-30% and the second crystallinity to 0.01%-5%, it is beneficial to control the melting of the sealant 100 within the temperature range of the first and second melting points, effectively regulating the melting pressure relief point of the sealant 100. This facilitates the rapid formation of pressure relief channels in the battery cell 300, improving heat dissipation efficiency and safety performance, and ensuring the sealing reliability of the sealant 100.
[0046] Optionally, the first degree of crystallinity can be a range of any one or any two of the following: 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, and 30%.
[0047] In some embodiments, the sealant 100 includes a first degree of crystallinity and a second degree of crystallinity, wherein the first degree of crystallinity is 5%-15% and the second degree of crystallinity is 0.5%-3%. This further facilitates controlling the melting of the sealant 100 within the temperature range of the first melting point and the second melting point, effectively regulating the melting and pressure relief point of the sealant 100, which is beneficial for the battery cell 300 to quickly form a pressure relief channel, improve heat dissipation efficiency and safety performance, and ensure the sealing reliability of the sealant 100.
[0048] Optionally, the second degree of crystallinity can be 0.01%, 0.03%, 0.05%, 0.07%, 0.09%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, or 2. A range consisting of any one or any two of the following: 3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3.0%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, 4.0%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%, 4.6%, 4.7%, 4.8%, 4.9%, and 5.0%.
[0049] In some embodiments, the total crystallinity of the sealant 100 is 2%-35%. If the crystallinity of the sealant 100 is less than 2%, its high fluidity after melting affects the sealing performance of the battery cell 300 and easily leads to leakage. If the crystallinity of the sealant 100 is greater than 35%, its low fluidity after melting affects the formation of a rapid pressure relief channel, reduces heat dissipation efficiency, and is detrimental to improving the safety performance of the battery cell. By limiting the total crystallinity of the sealant 100 to 2%-35%, it is beneficial to control the melting of the sealant 100 within the temperature range of the first melting point and the second melting point, effectively regulate the melting pressure relief point of the sealant 100, facilitate the rapid formation of a pressure relief channel in the battery cell 300, improve heat dissipation efficiency and safety performance, and ensure the sealing reliability of the sealant 100.
[0050] Optionally, the first degree of crystallinity can be any one or any combination of two of the following: 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, and 35%.
[0051] In some embodiments, the total crystallinity of the sealant 100 is 5%-18%. This is beneficial for controlling the melting of the sealant 100 within the temperature range of the first melting point and the second melting point, effectively regulating the melting pressure relief point of the sealant 100, facilitating the rapid formation of pressure relief channels in the battery cell 300, improving heat dissipation efficiency and safety performance, and ensuring the sealing reliability of the sealant 100.
[0052] In some embodiments, the number-average molecular weight Mn of sealant 100 is 10,000 g / mol to 130,000 g / mol. If the number-average molecular weight of sealant 100 is less than 10,000 g / mol, the melt viscosity of sealant 100 is too low, which is not conducive to processing and molding, and easily leads to low fluidity of sealant 100 after melting, reducing the encapsulation reliability of battery cell 300 under room temperature conditions. If the number-average molecular weight of sealant 100 is greater than 130,000 g / mol, the melt viscosity of sealant 100 is high, which is not conducive to processing and molding, and easily leads to low fluidity of sealant 100, affecting the formation of rapid pressure relief channels, reducing heat dissipation efficiency, and reducing the safety performance of battery cell. By limiting the number-average molecular weight Mn of sealant 100 to 10,000 g / mol to 130,000 g / mol, the encapsulation reliability of battery cell 300 under room temperature conditions and the mechanical strength of sealant 100 are improved.
[0053] Optionally, the number average molecular weight Mn of sealant 100 is any one or any combination of 10000 g / mol, 20000 g / mol, 30000 g / mol, 40000 g / mol, 50000 g / mol, 60000 g / mol, 70000 g / mol, 80000 g / mol, 90000 g / mol, 100000 g / mol, 110000 g / mol, 120000 g / mol, and 130000 g / mol.
[0054] In some embodiments, the weight-average molecular weight (Mw) of sealant 100 is 100,000 g / mol to 800,000 g / mol. If the weight-average molecular weight of sealant 100 is less than 100,000 g / mol, the mechanical strength of sealant 100 is low; if the weight-average molecular weight of sealant 100 is greater than 800,000 g / mol, the melt viscosity of sealant 100 is too high, making it difficult to flow. By limiting the weight-average molecular weight (Mw) of sealant 100 to 100,000 g / mol to 800,000 g / mol, the encapsulation reliability of battery cell 300 under normal temperature conditions and the mechanical strength of sealant 100 are improved.
[0055] Optionally, the weight-average molecular weight Mw of sealant 100 is any one or any combination of 100,000 g / mol, 200,000 g / mol, 300,000 g / mol, 400,000 g / mol, 500,000 g / mol, 600,000 g / mol, 700,000 g / mol, and 800,000 g / mol.
[0056] In some embodiments, Mw / Mn: 3-10, such that the sealant 100 includes multiple particles with different melting points, which improves the polydispersity index of the material, broadens the melting point range (melting range) of the sealant 100, and can adjust the melt index, which is beneficial to increase the fluidity of the material at high temperatures, melts quickly after reaching the melting point, and the structure of the sealant 100 collapses to form a pressure relief channel, thereby improving the heat dissipation efficiency of the battery cell 300.
[0057] Optionally, the ratio of Mw / Mn can be any one of 3, 4, 5, 6, 7, 8, 9, 10 or any combination of two of them.
[0058] In some embodiments, the sealant 100 comprises a first material and a second material. The number-average molecular weight Mn of the first material is 10,000 g / mol to 130,000 g / mol, and the weight-average molecular weight Mw is 100,000 g / mol to 400,000 g / mol. If the number-average molecular weight Mn of the first material is less than 10,000 g / mol and the weight-average molecular weight Mw of the first material is less than 100,000 g / mol, the melt viscosity is low, which is not conducive to processing and molding, and easily leads to high fluidity of the sealant 100 after melting, reducing the encapsulation reliability of the battery cell 300 under normal temperature conditions. If the number-average molecular weight of the first material is greater than 130,000 g / mol and the weight-average molecular weight Mw of the first material is greater than 400,000 g / mol, the melt viscosity is high, which is not conducive to processing and molding, and easily leads to low fluidity of the sealant 100, affecting the formation of rapid pressure relief channels, reducing heat dissipation efficiency, and reducing the safety performance of the battery cell 300. By limiting the number-average molecular weight Mn of the first material to 10000g / mol-130000g / mol and the weight-average molecular weight Mw to 100000g / mol-400000g / mol, it is easy to process and form, which is conducive to the rapid formation of pressure relief channels in the battery cell 300, improving heat dissipation efficiency and safety performance, and can also achieve the sealing reliability of the sealant 100.
[0059] Optionally, the number-average molecular weight Mn of the first material is any one or any combination of 10000 g / mol, 20000 g / mol, 30000 g / mol, 40000 g / mol, 50000 g / mol, 60000 g / mol, 70000 g / mol, 80000 g / mol, 90000 g / mol, 100000 g / mol, 110000 g / mol, 120000 g / mol, and 130000 g / mol.
[0060] Optionally, the weight-average molecular weight Mw of the first material is any one or any combination of 100,000 g / mol, 150,000 g / mol, 200,000 g / mol, 250,000 g / mol, 300,000 g / mol, 350,000 g / mol, and 400,000 g / mol.
[0061] In some embodiments, the number-average molecular weight Mn of the first material is 40,000 g / mol to 120,000 g / mol, and the weight-average molecular weight Mw is 150,000 g / mol to 300,000 g / mol. This further facilitates processing and molding, allows the battery cell 300 to quickly form a pressure relief channel, improves heat dissipation efficiency and safety performance, and ensures the sealing reliability of the sealant 100.
[0062] In some embodiments, the number-average molecular weight Mn of the second material is 50,000 g / mol to 130,000 g / mol, and the weight-average molecular weight Mw is 200,000 g / mol to 600,000 g / mol. If the number-average molecular weight Mn of the second material is less than 50,000 g / mol and the weight-average molecular weight Mw of the second material is less than 200,000 g / mol, it is easy to cause low structural strength of the sealant 100, reducing the encapsulation reliability of the battery cell 300 under normal temperature conditions. If the number-average molecular weight of the first material is greater than 130,000 g / mol and the weight-average molecular weight Mw of the second material is greater than 600,000 g / mol, the melt viscosity is too high, which is not conducive to processing and molding, and the polymer is easy to disperse unevenly, affecting the sealing and pressure relief performance of the sealant 100. By limiting the number-average molecular weight Mn of the second material to 50,000 g / mol-130,000 g / mol and the weight-average molecular weight Mw to 200,000 g / mol-600,000 g / mol, it is easy to process and form, which is conducive to the rapid formation of pressure relief channels in the battery cell 300, improving heat dissipation efficiency and safety performance, and can also achieve the sealing reliability of the sealant 100.
[0063] Optionally, the number-average molecular weight Mn of the second material is any one or any combination of 50,000 g / mol, 60,000 g / mol, 70,000 g / mol, 80,000 g / mol, 90,000 g / mol, 100,000 g / mol, 110,000 g / mol, 120,000 g / mol, and 130,000 g / mol.
[0064] Optionally, the weight-average molecular weight Mw of the second material is any one or any combination of 200,000 g / mol, 250,000 g / mol, 300,000 g / mol, 350,000 g / mol, 400,000 g / mol, 450,000 g / mol, 500,000 g / mol, 550,000 g / mol, and 600,000 g / mol.
[0065] In some embodiments, the number-average molecular weight Mn of the second material is 80,000 g / mol to 120,000 g / mol, and the weight-average molecular weight Mw is 250,000 g / mol to 4,500,000 g / mol. This further facilitates processing and molding, enabling the rapid formation of pressure relief channels in the battery cell 300, improving heat dissipation efficiency and safety performance, and ensuring the sealing reliability of the sealant 100.
[0066] In some embodiments, the first material accounts for 30-90% and the second material accounts for 10-70%. The first material has a first melting point and the second material has a second melting point. The first material melts rapidly at high temperatures to relieve pressure, while the second material provides structural strength under extreme operating conditions.
[0067] In some embodiments, the first material includes at least one selected from polyolefin resins, acid-modified polyolefin resins, polyethylene, polypropylene, ethylene elastomers, and styrene elastomers.
[0068] In some embodiments, the second material includes at least one selected from polyolefin resins, acid-modified polyolefin resins, polyethylene, polypropylene, ethylene elastomers, and styrene elastomers.
[0069] Please refer to Figure 1. One embodiment of this application provides a sealing assembly 200, including a connector 210, a fastener 220, and a sealant 100 as described in any of the above embodiments. The sealant 100 is located between the connector 210 and the fastener 220. The fastener 220 has a first opening 221, and a portion of the sealant 100 is exposed in the first opening 221.
[0070] In some embodiments, the sealant 100 is partially embedded in the first opening 221, which helps to improve the sealing performance of the battery cell 300.
[0071] Please refer to Figure 1. One embodiment of this application provides a battery cell 300, including a housing 310, an electrode assembly 320, a terminal post 330, and a sealant 100. The electrode assembly 320 is disposed inside the housing 310, and the terminal post 330 is connected to the electrode assembly 320 and exposed outside the housing 310.
[0072] In some embodiments, the housing 310 is a rigid housing, that is, the battery cell 300 is a rigid-cased battery cell.
[0073] In some embodiments, the outer diameter of the fastener 220 is larger than the outer diameter of the sealant 100, that is, along the thickness direction of the sealing assembly 200, the sealant 100 is located inside the fastener 220, and the portion of the fastener 220 that extends beyond the sealant 100 facilitates the provision of a reserved soldering position to weld the fastener 220 to the housing 310.
[0074] In some embodiments, the outer diameter of the fastener 220 is larger than the outer diameter of the connector 210, that is, along the thickness direction of the sealing assembly 200, the connector 210 is located inside the fastener 220, so as to facilitate the reserved welding position to weld the fastener 220 to the housing 310.
[0075] In some embodiments, the outer diameter of the connector 210 is smaller than the outer diameter of the sealant 100, which helps to improve the pressure relief function of the sealant 100.
[0076] Optionally, the fastener 220 is a circular ring, the sealant 100 is circular, and the connector 210 is annular. Optionally, the fastener 220 is a rectangular ring, the sealant 100 is rectangular, and the connector 210 is rectangular.
[0077] In some embodiments, the housing 310 includes a second opening 311, which is covered by a sealing assembly 200. The second opening 311 is a liquid injection port for injecting electrolyte.
[0078] In some embodiments, the fastener 220 connects to the housing 310. Along the thickness direction of the sealant 100, the first opening 221 and the second opening 311 overlap. The sealant 100 covers the second opening 311 and the first opening 221, thereby improving the sealing performance of the battery cell 300.
[0079] In some embodiments, the bonding area between the sealant 100 and the fastener 220 is S = 2 mm. 2 ≤S≤10mm 2 This helps the sealant 100 to seal the first opening 221 and the second opening 311, and facilitates the rapid formation of a pressure relief channel during pressure relief, thereby improving the heat dissipation efficiency and safety performance of the battery cell 300.
[0080] Optionally, the bonding area between the sealant 100 and the fastener 220 can be 2 mm. 2 2.5mm 2 3mm 2 3.5mm 2 4mm 2 4.5mm 2 5mm 2 5.5mm 2 6mm 2 6.5mm 2 7mm 2 7.5mm2 8mm 2 8.5mm 2 9mm 2 9.5mm 2 10mm 2 The range consisting of any one or any two of them.
[0081] In some embodiments, the diameter of the second opening 311 is larger than the diameter of the first opening 221, which helps to improve the adhesion between the fastener 220 and the housing 310.
[0082] In some embodiments, the first opening 221 is circular and the diameter of the first opening 221 is d1, 0.1mm≤d1≤4mm, so that the fastener 220 has a sufficient effective connection width, improves the reliability of the connection between the fastener 220 and the housing 310, and reduces the risk of the fastener 220 blocking the second opening 311 from releasing pressure.
[0083] Optionally, the diameter of the first opening 221 can be any one or any combination of two of the following: 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, 3mm, 3.1mm, 3.2mm, 3.3mm, 3.4mm, 3.5mm, 3.6mm, 3.7mm, 3.8mm, 3.9mm, and 4mm.
[0084] In some embodiments, the second opening 311 is circular, and the diameter of the second opening 311 is d2, 0.5mm≤d2≤5.5mm, so that the second opening 311 has better heat dissipation efficiency and reduces the sealing problem between the sealing assembly 200 and the second opening 311.
[0085] Optionally, the diameter of the second opening 311 can be 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, 3mm, or 0.5mm. The range consisting of any one or any two of the following: mm, 3.1mm, 3.2mm, 3.3mm, 3.4mm, 3.5mm, 3.6mm, 3.7mm, 3.8mm, 3.9mm, 4mm, 4.1mm, 4.2mm, 4.3mm, 4.4mm, 4.5mm, 4.6mm, 4.7mm, 4.8mm, 4.9mm, 5mm, 5.1mm, 5.2mm, 5.3mm, 5.4mm, and 5.5mm.
[0086] The present application will be further described below through specific embodiments.
[0087] 1. The specific method for hot box testing is as follows:
[0088] Adjust the furnace temperature to 25℃, place the lithium-ion cell sample inside the furnace and let it stand for 5 minutes; charge it to 3.0V with 0.2C DC; let it stand for 10 minutes; then charge it to 4.5V with 0.7C constant current, and then charge it to 0.025C constant voltage; let it stand for 10 minutes; take a picture before testing, measure the internal resistance of the voltage, and attach the temperature sensing wire to the surface of the cell. Then place the sample into the heating furnace chamber, raise the temperature to 130℃ at a rate of 5±2℃ / min and hold it for 60 minutes, and measure the internal resistance of the voltage. If the cell does not catch fire or explode, it indicates that it has passed the hot box test. The highest temperature that can be passed is defined as the hot box window of the cell.
[0089] 2. High temperature and high humidity test method:
[0090] After fully charging the lithium-ion battery cell at 1C, it is stored in a test environment with a test temperature of 60±2℃ and a humidity of 90±2.5% for 1008 hours. If the lithium-ion battery cell does not catch fire, explode, smoke, or leak, it passes the test.
[0091] 3. Number-average molecular weight test method:
[0092] Gel permeation chromatography (GPC) was used to determine the molecular weight distribution by separating polymer chains of different molecular weights. Tetrahydrofuran (THF) was selected as the solvent to dissolve the sample and prepare a solution of appropriate concentration (typically 0.1–1 mg / mL). The sample solution was filtered through a 0.45 μm filter membrane to remove insoluble matter and particles. The test temperature was set to 30 °C, and the flow rate to 1 mL / min. The injection volume was set to 100 μL. The response signal of each molecular weight fraction was recorded using a detector. The detection signal was converted into molecular weight using a calibration curve, and the number-average molecular weight (Mn), weight-average molecular weight (Mw), and polydispersity index (Mw / Mn) were calculated.
[0093] 4. Melt flow index test method:
[0094] Take approximately 2-10 grams of sealant sample; the exact weight can be adjusted based on the material's melt flow index and test conditions. Using a melt flow indexer, break the sealant into small particles to ensure a uniform sample. Set the test temperature (230℃) and load (2.16 kg). Place the sample into the melt flow indexer's barrel. Heat to 230℃, ensuring the sample is completely melted. Apply a 2.16 kg load, allowing the molten material to pass through a standard die. Record the weight of material passing through the die within a specified time. Melt Flow Index (MFR) = Weight of material passing through the die (g) / Test time (min).
[0095] 5. Test methods for crystallinity and melting point:
[0096] Take about 1-5 mg of sealant sample and place it in a crucible. Use a STA449F3 thermal analyzer to test it under the conditions of a temperature range of 25-800℃, a scan rate of 0.1-50K / min, and N2.
[0097] Preparation method of sealant 100: Particles with different melting points are mixed and stirred in a high-speed mixer at 25°C for 60 minutes, then melt-extruded and granulated in a progressive temperature range of 170°C-250°C. The granules are dried at 80°C and conveyed to a screw extruder through a vacuum feeder. They are then melt-plasticized in a progressive temperature range of 180°C-250°C at 10MPa. Finally, they are co-extruded and cast through a die at 230°C and 5MPa, cooled to room temperature for molding, and wound into a master roll. The master roll is then cured at room temperature for 24 hours.
[0098] High temperature and high humidity tests, as well as hot box tests, were conducted on groups of 100 cells (300).
[0099] Table 1
[0100] As can be seen from Table 1, when the range of the first melting point A is 50℃≤A≤120℃ and the range of the second melting point B is 120℃<B≤170℃, the pass rate of the hot box test and the high temperature and high humidity test is improved. This is beneficial for the cell to quickly form a pressure relief channel after expansion, improve heat dissipation efficiency, and thus improve the safety performance of the cell.
[0101] As shown in Table 1, when the difference between the first and second melting points is between 20℃ and 80℃, the respective functions of the two melting points can be effectively utilized. The first melting point A is beneficial for pressure relief, while the second melting point B is beneficial for sealing. This improves the pass rate of hot box testing and high temperature and humidity testing, thereby enhancing the safety performance of the battery cell. If the difference between the first and second melting points is too small, their respective functions overlap, making it impossible to simultaneously achieve pressure relief and sealing functions; if the difference is too large, the material uniformity is poor, manufacturability is low, and the function is unstable.
[0102] Table 2
[0103] As can be seen from Table 2, when sealant 100 has a third melting point, and the third melting point is greater than the second melting point, it is beneficial to improve the process yield of sealant 100.
[0104] Referring to Figure 2, this application also provides an electrical device 400 employing the aforementioned battery cell 300. In one embodiment, the electrical device 400 of this application may be, but is not limited to, electronic devices, drones, backup power supplies, electric vehicles, electric motorcycles, electric-assisted bicycles, power tools, large household batteries, etc.
[0105] Those skilled in the art should recognize that the above embodiments are merely illustrative of this application and are not intended to limit this application. Any appropriate changes and variations made to the above embodiments within the spirit and essence of this application fall within the scope of this application's disclosure.
Claims
1. A sealant, characterized in that, The sealant comprises a first material and a second material mixed together. The first material has a first melting point, and the second material has a second melting point. The range of the first melting point A is 50℃≤A≤120℃, and the range of the second melting point B is 120℃<B≤170℃.
2. The sealant as described in claim 1, characterized in that, The first melting point A is in the range of 50℃≤A≤100℃, and / or the second melting point B is in the range of 140℃≤B≤170℃.
3. The sealant as described in claim 1, characterized in that, The melt flow index of the sealant at 230°C and 2.16 kg load is 4 g / 10 min to 20 g / 10 min.
4. The sealant as described in claim 3, characterized in that, The sealant has a melt flow index of 6 g / 10 min to 14 g / 10 min at 230°C and a load of 2.16 kg.
5. The sealant as described in claim 4, characterized in that, The sealant has a melt flow index of 7.1 g / 10 min to 12 g / 10 min at 230°C and a load of 2.16 kg.
6. The sealant according to any one of claims 1 to 5, characterized in that, The difference between the first melting point and the second melting point is 20℃-80℃.
7. The sealant as described in claim 6, characterized in that, The difference between the first melting point and the second melting point is 40℃-60℃.
8. The sealant according to any one of claims 1 to 7, characterized in that, The sealant has a first degree of crystallinity and a second degree of crystallinity, wherein the first degree of crystallinity is 1%-30% and the second degree of crystallinity is 0.01%-5%.
9. The sealant according to any one of claims 1 to 8, characterized in that, The total crystallinity of the sealant is 2%-35%.
10. The sealant according to any one of claims 1 to 9, characterized in that, The sealant has a number-average molecular weight of Mn and a weight-average molecular weight of Mw, and at least satisfies one of the following conditions: 1) Mn is 10000 g / mol - 130000 g / mol; 2) Mw is 100,000 g / mol - 800,000 g / mol; 3) Mw / Mn is 3-10.
11. The sealant according to any one of claims 1 to 10, characterized in that, At least one of the following conditions must be met: 1) The first material accounts for 30-90%, and the second material accounts for 10-70%; 2) The number-average molecular weight Mn of the first material is 10000g / mol-130000g / mol, and the weight-average molecular weight Mw is 100000g / mol-400000g / mol; 3) The number-average molecular weight Mn of the second material is 50,000 g / mol-130,000 g / mol, and the weight-average molecular weight Mw is 200,000 g / mol-600,000 g / mol.
12. The sealant according to any one of claims 1 to 11, characterized in that, The sealant material includes at least one of polyolefin resins, acid-modified polyolefin resins, polyethylene, polypropylene, ethylene elastomers, and styrene elastomers.
13. A sealing assembly, characterized in that, It includes a connector, a fastener, and a sealant as described in any one of claims 1 to 12, the sealant being located between the connector and the fastener.
14. The sealing assembly as claimed in claim 13, characterized in that, The fastener has a first opening, and a portion of the sealant is embedded in the first opening.
15. The sealing assembly as claimed in any one of claims 13 to 14, characterized in that, The outer diameter of the fastener is larger than the outer diameter of the sealant.
16. The sealing assembly as claimed in any one of claims 13 to 15, characterized in that, The outer diameter of the fastener is larger than the outer diameter of the connector, and the outer diameter of the connector is smaller than the outer diameter of the sealant.
17. The sealing assembly according to any one of claims 13 to 16, characterized in that, The bonding area between the sealant and the fastener is S, 2mm. 2 ≤S≤10mm 2 .
18. A battery cell, characterized in that, It includes a housing and a sealing assembly as described in any one of claims 13 to 17, wherein the housing has a second opening and the sealing assembly covers the second opening.
19. The battery cell as described in claim 18, characterized in that, The fastener connects to the housing, and along the thickness direction of the sealant, the first opening and the second opening overlap, with the sealant covering both the second opening and the first opening.
20. The battery cell as described in claim 18 or 19, characterized in that, The battery cell must meet at least one of the following conditions: 1) The diameter of the first opening is d1, 0.1mm≤d1≤4mm; 2) The diameter of the second opening is d2, 0.5mm≤d2≤5.5mm; 3) The diameter of the second opening is greater than the diameter of the first opening.
21. An electrical appliance, characterized in that, Includes the battery cell as described in any one of claims 18 to 20.