Single battery upper cover assembly, single battery and battery pack

Abstract

The utility model belongs to the field of batteries, and particularly relates to a single battery upper cover assembly, a single battery and a battery pack. The technical problem that the explosion venting function fails due to the fact that the explosion venting membrane of the existing single battery is easy to loosen and fall off is solved. The upper cover assembly comprises an upper cover plate and a weak part integrally arranged on the upper cover plate; the strength of the weak part is smaller than that of the upper cover plate, and when the single battery is in thermal runaway, thermal runaway flue gas bursts the weak part to be discharged. The single battery comprises an upper cover assembly, and the battery pack comprises a plurality of single batteries. And the integrally arranged weak part and the upper cover plate are integrated, so that the hidden dangers of loosening, falling off and the like of the connecting part do not exist, the stability and the reliability of the structure are greatly improved, and good explosion venting performance can be always kept.

Description

Technical Field

[0001] This utility model belongs to the field of batteries, specifically a single-cell battery cover assembly, a single-cell battery, and a battery pack. Background Technology

[0002] The explosion venting membrane on existing single-cell batteries is usually attached to the battery cover by adhesive or other means. However, during long-term use, due to factors such as corrosion from internal battery chemicals, temperature changes, and mechanical vibrations, the connection between the explosion venting membrane and the cover may become loose or detach, leading to the failure of its explosion venting function. Summary of the Invention

[0003] The purpose of this utility model is to provide a single-cell battery cover assembly, a single-cell battery, and a battery pack, overcoming the technical problem that the existing single-cell battery explosion relief membrane is prone to loosening and falling off, leading to the failure of the explosion relief function.

[0004] The first aspect of this utility model provides a single-cell battery cover assembly, which is characterized in that: it includes a cover plate and a weak part integrally disposed on the cover plate; the strength of the weak part is less than the strength of the cover plate, and when the single-cell battery experiences thermal runaway, the thermal runaway flue gas breaks through the weak part and is discharged.

[0005] The weak part of this utility model is integrally set with the upper cover plate, which has at least the following advantages:

[0006] From a structural stability perspective, existing explosion-proof membranes are typically attached to the battery cover plate via adhesive or other methods. During long-term use, factors such as corrosion from internal battery chemicals, temperature changes, and mechanical vibrations can cause the connection between the membrane and the cover plate to loosen or detach, leading to a failure of its explosion-proof function. In contrast, the integrated weak point in this invention is a single unit with the cover plate, eliminating the risk of loosening or detachment at the connection point. This significantly improves structural stability and reliability, ensuring consistently excellent explosion-proof performance.

[0007] In terms of sealing, achieving an absolute seal at the junction of the existing explosion-proof membrane and the top cover faces numerous challenges. However, the seamless integration of the integrated weak point with the top cover effectively ensures the internal sealing of the battery under normal conditions, preventing the intrusion of external substances and providing a better environment for stable battery operation.

[0008] From a cost and manufacturing process perspective, existing explosion-proof membranes require additional materials and complex installation processes, which not only increases production costs but may also lead to inconsistent product quality due to human factors during manufacturing. In contrast, the integrated design of the weak point eliminates the need for additional installation steps during manufacturing, simplifying the production process, reducing production costs, and improving product consistency and quality stability.

[0009] Furthermore, a recessed area is created on the upper cover plate to form a weak point. Compared to some methods that create weak points by changing material composition or microstructure, creating a recessed area is simpler and allows for more intuitive and precise control over the strength and opening pressure of the weak point. Specifically, by controlling parameters such as the depth, shape, and area of ​​the recessed area, the opening of the weak point under a specific pressure can be accurately set, greatly improving the reliability of the explosion venting function.

[0010] Furthermore, the recessed area can be located on the upper surface of the upper cover plate, recessed towards the lower surface, forming a weak point. Alternatively, it can be located on the lower surface of the upper cover plate, recessed towards the upper surface, forming a weak point.

[0011] Recessed areas can be created on the upper or lower surface of the cover plate using conventional processing methods such as stamping and injection molding, resulting in low processing costs.

[0012] Furthermore, through holes can be made in the top cover plate along its width or length to form a weak section. When through holes are made in the top cover plate along its width or length to form a weak section, the flatness of the battery top cover plate can be maintained better than that formed by a recessed area.

[0013] Furthermore, the weak point is located between the two polarity terminals of the upper cover, which can dissipate the heat generated by thermal runaway in a timely manner and effectively alleviate local high temperature. In addition, compared with placing the weak point in other locations, it reduces interference with other functional areas of the battery and achieves a more efficient layout in a limited space.

[0014] Furthermore, the top cover and the thinner sections integrated into it are made of plastic. In terms of weight, plastic has a lower density compared to metal, significantly reducing the overall weight of the battery. In terms of cost, plastic raw materials are cheaper, and the molding process is simpler; for example, injection molding can be used to mold complex structures in a single step, reducing processing steps and lowering production costs.

[0015] From a molding process perspective, plastics are highly malleable, making it easy to manufacture various complex shapes of top covers and weak structural components. Whether it's recessed areas on the upper or lower surface, or through holes along the width or length, they can all be precisely molded.

[0016] The second aspect of this utility model provides a single-cell battery, which is characterized in that it includes a housing, which is formed by an upper cover assembly, a cylindrical body and a lower cover plate; wherein the upper cover assembly is the aforementioned single-cell battery upper cover assembly.

[0017] Furthermore, the shell strength is P, P1≤P≤P2; where P1 is the strength requirement of the shell during the formation stage and the normal charging and discharging stage of the battery; and P2 is the strength requirement of the shell during the thermal runaway stage.

[0018] The aforementioned single-cell battery casing is a sealed plastic casing that serves as a cavity for the electrode components and electrolyte, providing a sealing function. Simultaneously, the strength of the sealed casing must meet the strength requirements of the casing during the formation stage and the normal charge / discharge stages of the battery. That is, the sealed casing must possess sufficient strength to ensure that it will not crack under changes in the internal environment of the battery, such as temperature and pressure, during the formation stage and normal charge / discharge stages. Compared to existing finished plastic-cased single-cell batteries, this single-cell battery has a lower cost, thereby reducing the overall cost of the battery pack.

[0019] The third aspect of this utility model provides a battery pack, which is characterized in that it includes a pressure-bearing housing and n individual batteries as described above, where n is an integer greater than 1.

[0020] n individual cells are arranged inside the pressure tank; a venting channel is formed between the weak part of each individual cell and the pressure tank; the strength of the pressure tank meets the strength requirements of the shell during the thermal runaway stage, and the pressure tank is equipped with a venting part corresponding to the venting channel. When an individual cell experiences thermal runaway, the thermal runaway smoke breaks through the weak part, passes through the venting channel, breaks through the venting part, and exits the pressure tank.

[0021] The outer casing of this battery pack is a pressure-bearing casing, and its strength must meet the requirements for the casing during thermal runaway. That is, the pressure-bearing casing must have good strength to ensure that during thermal runaway, it can form a robust barrier, effectively isolating high-temperature flames and harmful gases, preventing the spread of thermal runaway, and improving the safety of the battery pack after thermal runaway. Furthermore, in the initial stage of thermal runaway, the runaway fumes can be discharged in an orderly manner through the explosion venting channel, effectively preventing their spread to the battery pack casing and thus preventing further deterioration of the thermal runaway situation.

[0022] Furthermore, the aforementioned battery pack also includes a heat exchange component that exchanges heat with the polarity terminals.

[0023] During battery pack operation, heat can easily accumulate at the polarized terminals due to current conduction. Heat exchange components can promptly remove this heat, ensuring the polarized terminals remain within a suitable operating temperature range. This not only helps maintain the stable performance of individual cells within the battery pack and reduces performance degradation caused by excessive temperature, but also further enhances the overall safety and reliability of the battery pack, preventing potential malfunctions caused by localized overheating.

[0024] The beneficial effects of this utility model are:

[0025] This invention integrates a weak section into the upper cover plate as a venting section for individual batteries. Compared with existing structures that use a venting membrane as the venting section, it has at least the following advantages:

[0026] 1. High structural stability;

[0027] Existing explosion-proof membranes are typically attached to the battery cover using adhesive or other methods. During long-term use, factors such as corrosion from internal battery chemicals, temperature changes, and mechanical vibrations can cause the connection between the membrane and the cover to loosen or detach, leading to a failure of its explosion-proof function. In contrast, the integrated weak point in this invention is a single unit with the cover, eliminating the risk of loosening or detachment. This significantly improves the structural stability and reliability, ensuring consistently excellent explosion-proof performance.

[0028] 2. Excellent sealing performance and low manufacturing cost;

[0029] Achieving an absolute seal at the junction of the existing explosion-proof membrane and the top cover plate presents numerous challenges and requires significant investment. In contrast, this invention features a seamlessly integrated weak point that connects to the top cover plate, ensuring excellent sealing performance. Furthermore, by eliminating the need for additional installation steps during manufacturing, it simplifies the production process, reduces costs, and improves product consistency and quality stability. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of the single-cell battery cover assembly in Example 1;

[0031] Figure 2 This is a schematic diagram of the structure of a single cell in Example 1;

[0032] Figure 3 This is a schematic diagram of the structure of the single-cell battery cover assembly in Example 2;

[0033] Figure 4 This is a schematic diagram of the structure of a single cell in Example 2;

[0034] Figure 5 This is a schematic diagram of the structure of the single-cell battery cover assembly in Example 3;

[0035] Figure 6 This is a schematic diagram of the structure of a single cell in Example 3;

[0036] Figure 7 This is a schematic diagram of the structure of a battery pack in Example 4;

[0037] Figure 8 This is a schematic diagram of the exploded structure of a battery pack in Example 4;

[0038] Figure 9This is a schematic diagram of the exploded structure of the second type of battery pack in Example 4;

[0039] Figure 10 This is a schematic diagram of the exploded structure of the third type of battery pack in Example 4;

[0040] Figure 11 This is a schematic diagram of another battery pack structure in Example 4;

[0041] Figure 12 This is a schematic diagram of the exploded structure of another battery pack in Example 4.

[0042] The attached figures are labeled as follows:

[0043] 1. Top cover plate; 2. Through groove; 3. Cylinder body; 4. Bottom cover plate; 5. Groove; 6. Through hole; 7. Pressure-bearing box body; 8. Individual battery; 9. Heat exchange component; 10. Polar terminal; 11. Explosion relief part; 12. Clearance hole; 13. Second channel. Detailed Implementation

[0044] To make the above-mentioned objectives, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this utility model.

[0045] Many specific details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0046] In the description of this utility model, it should be noted that the terms "top," "bottom," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," "third," "fourth," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0047] This utility model discloses a single-cell battery cover assembly. Unlike conventional cover assemblies, this utility model has an integrally formed weak part on the cover plate as a venting part for the single-cell battery. When thermal runaway occurs inside the single-cell battery and the internal pressure reaches a certain requirement, the thermal runaway fumes break through the weak part to form an opening and are discharged from the opening of the weak part.

[0048] Compared to the conventional design where the explosion vent membrane and the top cover are separate components, this invention integrates the top cover with the weak point, offering significant advantages.

[0049] First, in a split design, sealing the junction between the explosion-proof membrane and the top cover is challenging. It requires special sealants, complex sealing structures, and high-precision machining, resulting in high costs and complex processes. Even then, sealing failure can occur due to material aging, temperature changes, and other factors, leading to the failure of the explosion-proof function. In contrast, this new integrated design offers a seamless connection, inherently possessing excellent sealing performance. It eliminates the risk of loosening or detachment at the connection points, significantly improving structural stability and reliability, and maintaining consistently good explosion-proof performance. Second, split designs require substantial investment to achieve optimal sealing. This integrated design avoids expensive sealing materials and complex installation processes, significantly reducing costs. This results in significant economic benefits during mass production. Furthermore, the integrated design reduces the scrap rate due to poor sealing, further lowering overall costs. Third, compared to split designs, the integrated design provides a more uniform stress distribution at weak points, ensuring reliable opening under set pressure. This prevents premature opening or failure to open, providing more reliable protection for safe operation under extreme battery conditions and enhancing battery stability and safety. Finally, the integrated design simplifies the top cover assembly structure, reduces the number of parts, and makes battery packaging more convenient and efficient. In contrast, separate manufacturing and reassembly of the seals increases manufacturing uncertainty and the difficulty of quality control.

[0050] It should be noted that:

[0051] 1. The aforementioned weak part is integrally formed with the upper cover plate, meaning that the weak part and the upper cover plate are a single piece.

[0052] 2. The strength of the aforementioned weak point is less than that of the rest of the top cover plate to ensure that the weak point is the first to open in the event of thermal runaway. However, the strength of the weak point cannot be too low either; if the strength is too low, the weak point may deform before thermal runaway occurs, thus affecting battery performance. Therefore, during the design phase, various stresses that the top cover plate will bear during normal battery operation must be comprehensively considered, including internal pressure and external vibration. By rationally designing the corresponding structural dimensions of the weak point, the structural stability of the top cover plate under normal operating conditions can be ensured, while also ensuring that the weak point can reliably perform its explosion-proof function in the event of thermal runaway.

[0053] 3. A recessed area can be provided on the upper cover plate. The recessed area is usually provided on the upper surface and / or lower surface of the upper cover plate. That is, the recessed area can be recessed from the upper surface of the upper cover plate to the lower surface, or from the lower surface of the upper cover plate to the upper surface. The recessed area can be in the form of grooves, blind holes, or other structures. When it is on the upper surface of the upper cover plate, the recessed area can also be a through groove.

[0054] 4. Alternatively, a weak point can be formed by opening a through hole along the width or length of the upper cover plate, i.e., the opening of the through hole is located on the side wall of the upper cover plate.

[0055] 5. Alternatively, an annular groove can be made on the top cover plate, and the area enclosed by the annular groove can be used as a weak point.

[0056] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0057] Example 1

[0058] like Figure 1 The diagram shown is a structural schematic of the single-cell battery cover assembly in this embodiment, including a cover plate 1. A through groove 2 is formed on the upper surface of the cover plate 1, and the area of ​​the cover plate 1 corresponding to the bottom of the through groove 2 is taken as a weak part.

[0059] In this embodiment, the top cover 1 is made of plastic and can be integrally molded using injection molding to form the top cover 1 with the through groove 2. The low density of plastic significantly reduces the overall weight of the battery. Simultaneously, thanks to the good plasticity of plastic, the injection molding process allows for precise shaping of the through groove 2, ensuring the accuracy of its dimensions and shape. Integral molding also avoids additional seams, ensuring the overall sealing of the top cover 1 and effectively preventing the intrusion of external impurities. Furthermore, injection molding is a low-cost and highly efficient process, reducing processing steps and production costs, resulting in significant economic benefits in large-scale production.

[0060] In some other embodiments, a metal cover plate 1 may also be used, and a through groove 2 may be formed on the cover plate 1 by a stamping process.

[0061] In this utility model, for ease of description, the width direction of the upper cover plate 1 is defined as the x-direction, the length direction as the y-direction, and the thickness direction as the z-direction.

[0062] from Figure 1 As can be seen from the image, in this embodiment, the through groove 2 penetrates the upper cover plate 1 along the x-direction and is located between the two polarity terminals 10 of the upper cover plate 1.

[0063] From a thermal management perspective, the polar terminals 10 are usually the concentrated areas of heat generation in the battery. By placing the weak points near the two polar terminals 10, the heat generated by thermal runaway can be dissipated in a timely manner, effectively alleviating local high temperatures and optimizing the internal heat distribution of the battery.

[0064] In terms of structural layout, this arrangement makes the battery top cover 1 more compact and rational. Compared to placing the weakest part in other locations, it reduces interference with other functional areas of the battery, achieving a more efficient layout within a limited space.

[0065] In some other embodiments, the through slot 2 can also extend through the upper cover plate 1 along the length of the upper cover plate 1, avoiding the location of the polarity terminal 10.

[0066] The depth and width of the through groove 2 can be set according to specific needs to ensure that the area of ​​the upper cover plate 1 where the bottom of the through groove 2 is located can be opened under the set pressure.

[0067] However, it is important to note that the depth and width of the through-slot 2 should not be excessive. If the dimensions exceed a reasonable range, the through-slot 2 may deform due to insufficient strength when the battery has not experienced thermal runaway, thereby affecting battery performance. Therefore, during the design phase, it is necessary to comprehensively consider the various stresses that the top cover 1 will bear during normal battery operation, including internal pressure and external vibration. By rationally planning the corresponding dimensions of the through-slot 2, while ensuring the structural stability of the top cover 1 under normal operating conditions, it is also necessary to ensure that the through-slot 2 can reliably perform its explosion-venting function in the event of thermal runaway.

[0068] like Figure 2 As shown, a single battery 8 with the top cover assembly of this embodiment includes a housing, which is formed by the cylindrical body 3, the lower cover plate 4 and the aforementioned top cover assembly.

[0069] Corresponding to the aforementioned upper cover assembly, both the cylindrical body 3 and the lower cover plate 4 in this embodiment are made of plastic. The lower cover plate 4 and the cylindrical body 3 can be molded in one piece using injection molding, eliminating the need for separate processing and assembly. This significantly reduces production steps and shortens the production cycle. Furthermore, the injection-molded integral part exhibits uniform material distribution and tight bonding during the molding process, resulting in a more robust connection between the battery lower cover plate 4 and the cylindrical body 3, and higher overall structural strength. Additionally, reinforcing ribs can be integrally molded on the cylindrical body 3, effectively increasing its resistance to bending, compression, and torsion.

[0070] In this embodiment, since both the upper cover plate 1 and the cylindrical body 3 are made of plastic, a heat-sealing connection can be used. Heat-sealing ensures a continuous, uniform, and tight connection between the upper cover plate 1 and the cylindrical body 3, resulting in extremely high stability. External water, dust, and other impurities cannot enter the battery, providing excellent protection for the electrode components and ensuring the battery's performance and lifespan. Furthermore, the heat-sealing process is simple, and the parameters are easy to control.

[0071] It should be noted that the plastic material selected in this utility model should have the following properties:

[0072] First, it must have sufficient strength to ensure the stability of the battery structure;

[0073] Second, it has chemical corrosion resistance and can resist the corrosion of electrolytes;

[0074] Third, it has barrier properties, which can effectively prevent the electrolyte, gas and other substances inside the battery from leaking out, and at the same time prevent external impurities such as moisture and oxygen from entering the battery.

[0075] Fourth, it possesses excellent thermal stability. Batteries generate heat during charging and discharging, especially at high rates. This plastic material needs to maintain stable performance within a certain temperature range and will not soften, deform, or decompose due to high temperatures.

[0076] The plastic material used can be the same material used in existing plastic-cased single-cell batteries 8, or the plastic material disclosed in Chinese patents CN106543551A and CN106977894A.

[0077] To further reduce costs, the strength of the cell casing in this embodiment meets certain requirements. However, this embodiment does not require the casing to meet the strength requirements during the thermal runaway stage; it only needs to meet the strength requirements during the formation stage and normal charge / discharge processes. (Correspondingly, the strength of any weak points on the casing should also meet the strength requirements during the formation stage and normal charge / discharge processes.) During the formation stage and normal charge / discharge processes, the battery undergoes a series of chemical reactions and physical changes. During this process, certain pressure and heat are generated inside the battery. The casing needs to have sufficient strength to withstand this pressure and heat to ensure the smooth progress of the formation process and the normal use of the battery.

[0078] We can assume that the strength of the casing is P, P1≤P≤P2; where P1 is the strength requirement of the casing during the formation stage and the normal charging and discharging stage of the battery; and P2 is the strength requirement of the casing during the thermal runaway stage.

[0079] Under the premise of meeting the above strength requirements, in this embodiment, the thickness of the shell (cylinder 3, upper cover plate 1, and lower cover plate 4) is h, where h is less than h0, and h0 is the thickness of the plastic shell of a traditional single-cell battery 8; the thickness of the plastic shell of a traditional single-cell battery 8 is typically 5-8 mm. In this embodiment, the thickness of the shell can be between 1-4 mm, and the thickness of the upper cover plate 1 corresponding to the bottom of the through groove 2 is less than the thickness of the rest of the upper cover plate 1. By reducing the thickness of the shell of a traditional single-cell battery 8 with a plastic shell, better heat dissipation can be achieved, and the battery energy density can also be increased. In addition, reducing the thickness of the plastic shell means using less plastic material, which helps to save material costs and provides an economic advantage for large-scale production and application.

[0080] Example 2

[0081] Unlike Embodiment 1, this embodiment has a groove 5 on the lower surface of the upper cover plate 1, and the area of ​​the upper cover plate 1 corresponding to the bottom of the groove 5 is a weak part.

[0082] Specifically, such as Figure 3 As shown, in this embodiment, the groove 5 extends along the x-direction. Similar to embodiment 1, the groove 5 is located between the two polar terminals 10.

[0083] The depth and width of the groove 5 can be set according to specific needs to ensure that the area of ​​the upper cover plate 1 where the bottom of the groove 5 is located can be opened under the set pressure.

[0084] However, it is also important to note that the depth and width of the groove 5 should not be too large. If the dimensions exceed a reasonable range, the groove 5 may deform due to insufficient strength when the battery has not experienced thermal runaway, thus affecting battery performance. Therefore, during the design phase, it is necessary to comprehensively consider the various stresses that the top cover 1 will bear during normal battery operation, including internal pressure and external vibration. By rationally planning the corresponding dimensions of the groove 5, it is possible to ensure the structural stability of the top cover 1 under normal operating conditions while ensuring that the groove 5 can reliably perform its explosion-proof function in the event of thermal runaway.

[0085] Compared to the example of opening a through groove 2 on the upper surface of the top cover 1 in Example 1, this example can better maintain the flatness of the battery top cover 1.

[0086] In addition, during normal operation of the single cell 8, the inner cavity of the groove 5 can serve as a gas storage cavity, where the gas generated inside the single cell 8 can be stored, thus reducing the degree of bulging of the single cell 8 casing.

[0087] like Figure 4 As shown, this is a single battery 8 with the top cover assembly of this embodiment, including a housing, which is formed by the cylindrical body 3, the lower cover plate 4, and the aforementioned top cover assembly. Except for the top cover assembly, which differs from that of Embodiment 1, the rest of the structure is the same as that of Embodiment 1, and will not be described again here.

[0088] Example 3

[0089] Unlike the above embodiments, this embodiment has a through hole 6 in the upper cover plate 1 along its width direction, forming a weak part.

[0090] Specifically, such as Figure 5 As shown, this embodiment also uses a plastic cover plate 1, which can be integrally molded with a through hole 6 using an injection molding process.

[0091] As can be seen from the figure, in this embodiment, the through hole 6 penetrates the upper cover plate 1 along the width direction of the upper cover plate 1 and is located between the two polarity terminals 10 of the upper cover plate 1.

[0092] In some other embodiments, a through hole 6 along the length of the upper cover plate 1 may be formed to create a weak point.

[0093] The cross-sectional shape and size of the through hole 6 can be set according to specific requirements to ensure that the area of ​​the upper cover plate 1 where the bottom of the through hole 6 is located can be opened under the set pressure.

[0094] However, it is also important to note that the through hole 6 should not be too large. If it exceeds a reasonable range, the through hole 6 may deform due to insufficient strength when the battery has not experienced thermal runaway, thus affecting battery performance. Therefore, during the design phase, it is necessary to comprehensively consider the various stresses that the top cover 1 will bear during normal battery operation, including internal pressure and external vibration. By rationally planning the appropriate size of the through hole 6, while ensuring the structural stability of the top cover 1 under normal operating conditions, it is also necessary to ensure that the through hole 6 can reliably perform its explosion-proof function in the event of thermal runaway.

[0095] Compared to the weak point in Embodiment 1, this embodiment can also better maintain the flatness of the battery cover plate 1.

[0096] like Figure 6 As shown, this is a single battery 8 with the top cover assembly of this embodiment. Except for the top cover assembly, which is different from that of Embodiment 1, the rest of the structure is the same as that of Embodiment 1, and will not be described again here.

[0097] Example 4

[0098] This embodiment is a battery pack, including a pressure-bearing housing 7 and 12 individual battery cells 8 as described in the above embodiment. In other embodiments, the number of individual battery cells 8 can be adjusted according to actual needs.

[0099] Its structure is as follows Figures 7 to 10 As shown, Figure 8 The example used is the single cell 8 in Example 1. Figure 9 Taking the single cell 8 in Example 2 as an example. Figure 10 Taking the single cell 8 in Example 3 as an example.

[0100] The 12 individual cells 8 in the above embodiments are arranged inside the pressure-bearing housing 7, forming a venting channel between the individual cells where the pressure-bearing housing is weak.

[0101] Figure 8 In this design, the weakest point is a through-slot. When the through-slots of each individual battery cell are connected, a venting channel is formed. This venting channel is located between the weakest point of each individual battery cell and the pressure-bearing casing. Alternatively, a channel can be provided on the pressure-bearing casing, covering the through-slots of each individual battery cell and forming a larger cavity venting channel.

[0102] Figure 9 In the middle, the weak part is a groove opened on the lower surface of the upper cover plate. A second channel 13 needs to be set on the pressure-bearing housing. The second channel covers the weak part of each individual battery cell and forms a venting channel between the second channel and the weak part of the individual battery cell.

[0103] Figure 10 In the middle, the weak part is the through hole opened on the upper cover plate. The through holes of each individual battery are connected to form a venting channel. This venting channel is also located between the weak part (the bottom of the through hole) and the pressure-bearing shell.

[0104] The pressure chamber 7 is provided with an explosion relief part 11 corresponding to the explosion relief channel (the explosion relief part 11 here can also be called an explosion-proof part, explosion-proof port or explosion relief port, etc., and is usually provided with a pressure relief valve or explosion relief membrane, etc.); when the single cell 8 thermally runs away, the thermal runaway smoke breaks through the weak part, passes through the explosion relief channel, breaks through the explosion relief part 11 and is discharged from the pressure chamber 7.

[0105] In the initial stage of thermal runaway, the thermal runaway flue gas can be discharged in an orderly manner through the explosion relief channel, effectively preventing it from spreading into the pressure tank 7 of the battery pack, thereby preventing further deterioration of the thermal runaway situation.

[0106] The strength of the pressure-bearing housing 7 needs to meet the strength requirements of the casing during thermal runaway, meaning that the pressure-bearing housing 7 must have good strength. This design not only effectively resists the high-pressure impact during thermal runaway with the reinforced outer casing, greatly improving the overall safety of the battery pack; especially when plastic material is used as the casing of the internal individual cells 8, the pressure-bearing housing 7 can form a robust thermal barrier. Even in the extreme case where the casing of the individual cell 8 melts, it can effectively isolate high-temperature flames and harmful gases, preventing the spread of thermal runaway and improving the safety of the battery pack after thermal runaway. In addition, when plastic material is used as the casing of the internal individual cells 8, an anti-seepage membrane can be provided between each individual cell 8 and the pressure-bearing housing 7 to prevent the electrolyte inside each individual cell 8 from seeping out.

[0107] Compared to other materials, the metal pressure tank 7 is more reliable in emergency situations such as thermal runaway. It can withstand greater impact and destructive forces, reducing the likelihood of accidents and protecting the safety of personnel and surrounding equipment. In this embodiment, the pressure tank 7 does not directly contact the electrolyte, so an iron, steel, or stainless steel shell can be used. An iron shell offers advantages in strength and cost, making it a viable option in scenarios where cost is a primary concern and strength requirements are not particularly stringent. A steel shell provides relatively high strength, offering more reliable protection for the battery and is suitable for applications with high safety and structural strength requirements. A stainless steel shell not only possesses good strength properties but also excellent corrosion resistance, making it perform exceptionally well in battery applications that may face humid or corrosive environments. This effectively extends battery life and ensures stable operation in complex environments.

[0108] like Figure 11 and Figure 12 As shown, in this embodiment, a clearance hole 12 is provided on the top plate of the pressure-bearing box corresponding to the polarity terminal 10 of each individual battery 8; the polarity terminal 10 of each individual battery 8 extends out of the clearance hole 12; the top plate area of ​​the pressure-bearing box corresponding to the clearance hole 12 is fixedly sealed with the housing of the individual battery 8.

[0109] To optimize the heat dissipation performance of the battery pack, this embodiment may further include a heat exchange component 9 to exchange heat with the polarity terminal 10. As a key component connecting the battery's internal structure to the external environment, the polarity terminal 10 allows current to flow in and out of the battery during charging and discharging. When heat is generated inside the battery, heat dissipation through the polarity terminal 10 provides a relatively direct heat conduction path. Heat can be rapidly conducted from inside the battery to the polarity terminal 10, and then dissipated to the external environment from the polarity terminal 10. Furthermore, since the polarity terminal 10 is typically located at the positive and negative terminals of the battery, these areas are often where heat is concentrated during charging and discharging. By dissipating heat from the polarity terminal 10, the temperature of these critical components can be reduced more effectively.

[0110] The heat exchange component 9 is a heat transfer tube; each polarity terminal 10 of the individual cell 8 is provided with a through groove 2 or through hole for installing the heat transfer tube; the heat transfer tube is fixed in the through groove 2 or through hole of each polarity terminal 10 of the individual cell 8. By using the heat transfer tube on the polarity terminal 10, the heat generated inside the battery is conducted to the heat transfer tube through the polarity terminal 10, and then the heat transfer tube dissipates the heat to achieve heat dissipation of the battery.

[0111] The heat exchange component 9 can also be a heat exchange device, which is disposed on top of each individual battery cell 8. The polar terminal 10 passes through the heat exchange device, and at least a portion of the structure of the polar terminal 10 is located inside the heat exchange device and is in direct contact with the heat exchange medium. Another portion of the structure of the polar terminal 10 is located outside the heat exchange device and serves as an electrical connection. The sidewall of the polar terminal 10 is sealed to the heat exchange device. By adopting a direct heat exchange method, a portion of the structure of the polar terminal 10 is placed directly inside the heat exchange medium flow cavity (the inner cavity of the heat exchange device), so that the polar terminal 10 is in direct contact with the heat exchange medium, thereby achieving heat exchange of the polar terminal 10. Compared with the indirect heat exchange method, it has a shorter heat exchange path, and the heat exchange medium acts directly on the polar terminal 10, improving the utilization efficiency of the heat exchange medium and improving the heat exchange efficiency of the battery.

[0112] In this embodiment, an insulating sealant layer can also be provided between each individual battery cell 8 and between each individual battery cell 8 and the pressure-bearing housing. The insulating sealant layer is mainly laid in the space between each individual battery cell 8 and the pressure-bearing housing, and the heat exchange components 9 inside the pressure-bearing housing are all located within the insulating sealant layer; when there is a gap between each individual battery cell 8, the insulating sealant liquid can also penetrate into the gap to form an insulating sealant layer.

[0113] It should be noted that no insulating sealant layer is installed inside the explosion venting channel.

[0114] In this embodiment, the insulating sealant layer has at least the following advantages:

[0115] 1. Prevent condensation;

[0116] During long-term use, due to the temperature difference between the inside and outside of the heat exchange component 9, condensation will form on the surface. When the condensation accumulates to a certain amount, it may cause a short circuit. By laying an insulating sealant layer to completely wrap the heat exchange component 9, when condensation forms on the surface of the heat exchange component 9, the battery short circuit can be prevented under the protection of the insulating sealant layer.

[0117] II. Further improve the stability of each individual battery cell 8 within the pressure tank;

[0118] The insulating sealant penetrates into the gaps between each individual cell 8 and between each individual cell 8 and the pressure tank, which can further improve the stability of each individual cell 8 within the pressure tank.

[0119] use Figure 11 and Figure 12 In the structure shown, an insulating sealant layer can also be laid on the top plate of the pressure tank, and the heat exchange component 9 is located inside the insulating sealant layer. When condensation occurs on the surface of the heat exchange component 9, the battery short circuit can be prevented under the protection of the insulating sealant layer.

Claims

1. A single-cell battery cover assembly, characterized in that: It includes an upper cover plate and a weak part integrally set on the upper cover plate; the strength of the weak part is less than the strength of the upper cover plate, and when the single cell thermal runaway occurs, the thermal runaway smoke breaks through the weak part and is discharged.

2. The single-cell battery cover assembly according to claim 1, characterized in that: A recessed area is created on the top cover plate to form a weak point.

3. The single-cell battery cover assembly according to claim 2, characterized in that: A recessed area is created on the upper surface of the top cover plate, which is recessed downwards to form a weak point; Alternatively, a recessed area can be created on the lower surface of the upper cover plate, recessed towards the upper surface, forming a weak point.

4. The single-cell battery cover assembly according to claim 1, characterized in that: A through hole is made in the top cover plate along its width or length to form a weak point.

5. The single-cell battery cover assembly according to claim 1, characterized in that: The weak point is located between the two polarity terminals of the upper cover plate.

6. The single-cell battery cover assembly according to any one of claims 1 to 5, characterized in that: The top cover and the weak part integrated on the top cover are made of plastic.

7. A single-cell battery, characterized in that: The device includes a housing, which is formed by an upper cover assembly, a cylindrical body, and a lower cover plate; wherein the upper cover assembly is the single-cell battery upper cover assembly as described in any one of claims 1 to 6.

8. The single-cell battery according to claim 7, characterized in that: The shell strength is P, where P1≤P≤P2; where P1 is the strength requirement of the shell during the formation stage and the normal charging and discharging stage of the battery; and P2 is the strength requirement of the shell during the thermal runaway stage.

9. A battery pack, characterized in that: It includes a pressure-bearing housing and n individual batteries as described in claim 7 or 8, where n is an integer greater than 1; n individual cells are arranged inside the pressure tank, and a venting channel is formed between the weak part of each individual cell and the pressure tank. The pressure tank has the strength required for the shell during the thermal runaway stage. The pressure tank is equipped with a venting section corresponding to the venting channel. When a single cell experiences thermal runaway, the thermal runaway flue gas breaks through the weak part, passes through the venting channel, and then breaks through the venting section to exit the pressure tank.

10. The battery pack according to claim 9, characterized in that: It also includes heat exchange components that exchange heat with the polarity terminals.

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