Battery cell

Abstract

The invention relates to the technical field of battery cell manufacturing, and provides a battery cell which comprises a shell and a bottom supporting plate, an accommodating space for mounting the electrode assembly is formed in the shell, and a pressure relief hole is formed in the bottom wall of the shell; the bottom supporting plate is arranged between the bottom wall and the electrode assembly and is used for supporting the electrode assembly; the surface, facing the bottom wall, of the bottom supporting plate is provided with a plurality of protruding parts, and the protruding parts are supported on the inner surface of the bottom wall, so that an exhaust channel is formed between the bottom supporting plate and the bottom wall. And the exhaust channel is communicated with the pressure relief hole. According to the invention, through the arrangement of the protruding part, an exhaust channel is formed between the bottom supporting plate and the inner side surface of the bottom wall of the shell, so that rapid exhaust of gas can be realized during thermal runaway, and the electrode assembly is prevented from blocking the pressure relief hole.

Description

Technical Field

[0001] This invention relates to the field of battery cell manufacturing technology, and more particularly to a battery cell. Background Technology

[0002] To improve the safety performance of individual battery cells, pressure relief mechanisms are typically installed on them. When gas is generated inside a battery cell due to abnormal operation, the gas can be released through the pressure relief mechanism to prevent a major safety accident.

[0003] To maximize cell capacity and ensure safer battery pack assembly, moving the pressure relief structure from the cover plate to the side wall of the casing to achieve thermal and electrical separation is a very effective method.

[0004] In related technologies, pressure relief valves are typically located at the bottom of the battery casing, away from the electrical connection structures on the cover, to achieve effective thermoelectric separation. However, when a cell experiences thermal runaway, the electrode components sink to the bottom of the casing due to their own gravity, potentially covering the pressure relief vent and causing it to become blocked. In this situation, the gas inside the casing cannot be quickly released through the pressure relief valve, leading to excessive internal pressure and increasing the risk of explosion. Therefore, there is an urgent need for a cell design that can ensure the pressure relief vent remains open during thermal runaway. Summary of the Invention

[0005] This invention provides a battery cell that addresses the defect in the prior art where the electrode assembly tends to sink and block the pressure relief hole during thermal runaway.

[0006] This invention provides a battery cell, comprising: a housing and a base plate; the housing has an accommodating space for mounting an electrode assembly, and a pressure relief hole is provided on the bottom wall of the housing; the base plate is disposed between the bottom wall and the electrode assembly for supporting the electrode assembly; wherein, the surface of the base plate facing the bottom wall has a plurality of protrusions, the plurality of protrusions are supported on the inner surface of the bottom wall, thereby forming an exhaust channel between the base plate and the bottom wall; and the exhaust channel communicates with the pressure relief hole.

[0007] According to the battery cell provided by the present invention, the melting point Tm of the base plate is ≥250℃.

[0008] According to the battery cell provided by the present invention, a plurality of grooves are provided on both sides near the bottom plate in the width direction, and the bottom of the grooves protrudes to the side away from the electrode assembly to form the protrusion.

[0009] According to the battery cell provided by the present invention, each of the sinks is provided with a through hole.

[0010] According to the battery cell provided by the present invention, the edge of the groove opening and the edge of the groove bottom are both formed with rounded chamfers.

[0011] According to the battery cell provided by the present invention, the number of sinks on both sides of the bottom support plate in the width direction is the same, and they are arranged in parallel with intervals.

[0012] According to the battery cell provided by the present invention, the pressure relief hole is located in the gap area between adjacent grooves in the width direction of the bottom support plate.

[0013] According to the battery cell provided by the present invention, the connection between the bottom wall and the inner sidewall of the housing is formed with a rounded corner structure.

[0014] According to the battery cell provided by the present invention, the radius of the rounded corner structure is r, the thickness of the bottom plate is a, and the protrusion height b of the protrusion satisfies: 0.2mm≤b≤ra.

[0015] According to the battery cell provided by the present invention, the radius of the rounded corner structure is 1.0mm≤r≤2.5mm, and the thickness of the bottom support plate is 0.1mm≤a≤0.3mm.

[0016] The battery cell provided by the present invention, through the setting of the protrusion, forms an exhaust channel between the bottom support plate and the inner surface of the bottom wall of the housing, thereby enabling rapid gas discharge in the event of thermal runaway and preventing the electrode assembly from clogging the pressure relief hole. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is an exploded view of the overall structure of the battery cell provided by the present invention.

[0019] Figure 2 This is a schematic diagram of the internal structure of the battery cell provided by the present invention.

[0020] Figure 3 This is a three-dimensional structural diagram of the battery cell provided by the present invention.

[0021] Figure 4 This is an overall structural diagram of the bottom support plate in the battery cell provided by the present invention.

[0022] Figure 5 This is a schematic diagram of the assembly relationship between the bottom support plate and the housing in the battery cell provided by the present invention.

[0023] Figure label: 10. Housing; 101. Accommodation space; 102. Bottom wall; 103. Pressure relief hole; 104. Rounded corner structure; 20. Cover plate assembly; 30. Insulating film; 40. Bottom support plate; 401. Protrusion; 402. Settlement groove; 403. Through hole; 404. Exhaust passage; 50. Explosion-proof valve. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0025] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the purpose of clarifying the embodiments of the present invention 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. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0026] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention according to the specific circumstances.

[0027] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0028] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0029] In related technologies, to prevent significant safety hazards caused by thermal runaway of the battery cell, the pressure relief port of the battery cell is located at the bottom of the casing, and a pressure relief valve is installed inside the pressure relief port. This keeps the pressure relief location away from the terminal post on the cover plate, improving its safety performance. However, this method can block the pressure relief port on the casing in the event of thermal runaway of the battery cell, preventing the gas inside the casing from escaping and exacerbating the safety risk.

[0030] To address the issues in the relevant technologies, the following will be discussed in conjunction with... Figures 1-3 This invention describes a battery cell comprising a housing 10 and a base plate 40. The housing 10 has an accommodating space 101 for mounting electrode assemblies, and a pressure relief hole 103 is provided on the bottom wall 102 of the housing 10. The base plate 40 is disposed between the bottom wall 102 and the electrode assembly to support the electrode assembly. The base plate 40 has multiple protrusions 401 on its surface facing the bottom wall 102, which support the inner surface of the bottom wall 102, forming an exhaust channel 404 between the base plate 40 and the bottom wall 102. The exhaust channel 404 communicates with the pressure relief hole 103. In the event of thermal runaway of the battery cell, effective support is required to prevent the electrode assembly from sinking and blocking the pressure relief hole 103 on the battery cell housing 10 under gravity. In this embodiment, the protrusions 401 effectively support the electrode assembly and form the exhaust channel 404, thereby enabling rapid gas discharge, improving the stability of the entire electrode assembly support, and enhancing the safety of the battery cell.

[0031] Specifically, the battery cell housing 10 has a perimeter side wall and a bottom wall 102 that enclose a receiving space 101. A cover plate assembly 20 is provided on the top of the housing 10, and the electrode assembly is disposed within the receiving space 101 to achieve overall assembly. A bottom support plate 40 is located between the electrode assembly and the bottom wall 102 of the housing 10, and it is used to support the electrode assembly.

[0032] The protrusion 401 is integrally formed with the bottom support plate 40. The protrusion 401 can increase the distance between the bottom support plate 40 and the bottom wall 102 of the housing 10, thereby forming a gap space between the main body plate of the bottom support plate 40 and the bottom wall 102 of the housing 10. The gap space forms an exhaust channel 404, which connects the internal space of the housing 10 and the pressure relief hole 103, so as to realize the rapid discharge of gas inside the housing 10 in the event of thermal runaway.

[0033] In a specific configuration, the electrode assembly includes electrode groups and electrodes, as well as an insulating film 30, which wraps around the electrode groups and electrodes. During connection, a base plate 40 is positioned below the insulating film 30. In the event of thermal runaway, the insulating film 30 will rapidly melt and release high-temperature, high-pressure gas. This gas can then flow rapidly through the exhaust channel 404 and be quickly discharged through the pressure relief hole 103, improving the cell's safety performance.

[0034] It is understandable that after the cover plate assembly 20 is connected, the internal space of the housing 10 is a sealed space. Once the battery cell experiences thermal runaway, the pressure inside the housing 10 will increase rapidly. Typically, the pressure relief hole 103 contains a pressure relief component, which can open to connect the internal space with the external environment and release the internal pressure after the internal pressure reaches a set value. In this embodiment, the protrusion 401 increases the distance between the bottom support plate 40 and the inner surface of the bottom wall 102 of the housing 10, thereby forming an exhaust channel 404. This allows for timely discharge of high-pressure gas generated internally, improving the safety performance of the battery cell during thermal runaway.

[0035] In conjunction with the above embodiments, the melting point Tm of the base plate 40 is ≥250℃. In the initial stage of thermal runaway of the battery cell, especially when the internal temperature is <250℃, gas is rapidly generated internally in a large quantity. This embodiment limits the melting point of the base plate 40 to greater than 250℃, enabling it to provide effective support within this temperature range. This allows it to support the electrode assembly and maintain the unobstructed flow of the exhaust channel 404, facilitating the rapid discharge of high-pressure gas.

[0036] Specifically, the melting point of the base plate 40 is higher than that of the insulating film 30. In the event of thermal runaway, the insulating film 30 melts rapidly, allowing the gas inside the casing 10 to be quickly discharged through the exhaust channel 404, thereby relieving pressure and improving the safety performance of the battery cell.

[0037] It is understood that the electrode assembly inside the casing 10 is generally composed of positive and negative electrode materials. The function of the insulating film 30 is to separate them, prevent short circuits, and ensure the safety and stability of the battery. Specifically, the insulating film 30 wraps around the positive and negative electrode materials to achieve isolation between them. In this embodiment, the cell base plate 40 is located below the insulating film 30, and the protrusion 401 contacts the inner surface of the bottom wall 102 of the casing 10 to support the electrode assembly. An exhaust channel 404 is formed between the bottom wall 102 of the casing 10 and the main body of the base plate 40 to allow for the timely discharge of internal high-pressure gas.

[0038] In some embodiments, such as Figure 4 As shown, multiple grooves 402 are provided on both sides near the base plate 40 in the width direction. The bottom of the grooves 402 protrudes towards the side away from the electrode assembly, forming a protrusion 401. The grooves 402 make the overall weight of the base plate 40 lighter, which is conducive to the lightweight design of the battery cell and can improve the safety performance of the battery cell.

[0039] Specifically, multiple grooves 402 are stamped on the bottom support plate 40. The grooves 402 can protrude on the side facing the bottom wall 102, thereby achieving effective support. This method can avoid the setting of additional materials, make the bottom support plate 40 lightweight as a whole, and facilitate mass production by stamping, reducing the difficulty of manufacturing.

[0040] In conjunction with the above embodiments, each sink 402 is provided with a through hole 403. The provision of the through hole 403 can further reduce the manufacturing difficulty of the protrusion 401 and enhance the venting rate during thermal runaway, thereby further improving the safety performance of the battery cell.

[0041] Understandably, the base plate 40 is a plate-like structure. The sink 402 is positioned during processing via the through-hole 403, which facilitates its shaping, improves processing accuracy, and reduces processing difficulty. Furthermore, during cell production, the electrode assembly may shift, allowing internal gas to escape directly through the through-hole 403, enabling rapid gas discharge. Additionally, in the event of thermal runaway, structural shifting may occur; in this case, the through-hole 403 can connect with the exhaust channel 404, facilitating the rapid discharge of high-pressure internal gas.

[0042] In conjunction with the above embodiments, both the opening edge and the bottom edge of the settling tank 402 are formed with rounded chamfers. The rounded chamfers improve the overall structural stability.

[0043] Specifically, the upper surface of the base plate 40 is in contact with the insulating film 30 of the electrode assembly. In this embodiment, by setting a rounded chamfer structure at the edge of the slot, damage to the insulating film 30 can be avoided, thus improving the stability of the structure.

[0044] Furthermore, the rounded chamfer structure at the bottom edge of the groove facilitates the stamping of the sink 402 and ensures that there are no sharp edges or thorns, thus improving the stability of the assembled structure.

[0045] In some embodiments, the number of recesses 402 on both sides of the base plate 40 in the width direction is the same, and they are arranged side by side with intervals. The base plate 40 needs to effectively support the electrode assembly and ensure the stability of the support. In this embodiment, by distributing the recesses 402 on both sides of the base plate 40 in the width direction, the force on each protrusion 401 can be uniform, thereby improving the stability of the support of the base plate 40.

[0046] Specifically, the same number of sinkers 402 are arranged in the width direction of the base plate 40, and the sinkers 402 on each side are evenly spaced along the length direction of the base plate 40. This makes the sinkers 402 occupy most of the entire base plate 40, thereby achieving effective support and making the support more stable.

[0047] In conjunction with the above embodiments, such as Figure 2 , Figure 3 As shown, the pressure relief hole 103 is located in the gap area between adjacent grooves 402 in the width direction of the bottom support plate 40. In the event of thermal runaway of the battery cell, it is necessary to release the internal gas pressure in a timely and rapid manner. In this embodiment, by placing the pressure relief hole 103 between adjacent grooves 402 in the width direction, it is possible to facilitate the rapid discharge of internal gas.

[0048] Specifically, the grooves 402 in the width direction of the bottom support plate 40 have a certain spacing, which is used to form an exhaust channel 404. The exhaust channel 404 is directly connected to the pressure relief hole 103, which allows the high-pressure gas inside to directly enter the pressure relief hole 103 along the exhaust channel 404 and then be discharged.

[0049] It is understood that an explosion-proof valve 50 is provided in the pressure relief hole 103. The explosion-proof valve 50 is used to open when the pressure inside the cell housing 10 reaches a predetermined threshold, thereby enabling the discharge of high-pressure gas inside. In this embodiment, by setting the pressure relief hole 103 in the exhaust channel 404, it is possible to respond in a timely manner when the cell thermally runs away, and to enable the high-pressure gas inside to be discharged quickly along the pressure relief hole 103.

[0050] In some embodiments, a rounded corner structure 104 is formed at the connection between the bottom wall 102 and the inner sidewall of the housing 10. When thermal runaway occurs in the battery cell, a large amount of high-temperature gas and ejected material is generated from the bottom electrode assembly and needs to flow rapidly to the pressure relief hole 103 through the exhaust channel 404 below the bottom support plate 40. Right-angle structures (90° turns) can create turbulent vortex zones and flow dead zones, significantly increasing flow resistance. In this embodiment, the rounded corner structure 104 facilitates the rapid discharge of internal gas.

[0051] Specifically, the rounded corner structure 104 can also improve the yield rate during processing. Right-angle stretching can easily lead to material thinning or cracking, while the rounded corner design allows the material to flow evenly, improving the stamping success rate.

[0052] Furthermore, since the rounded corner structure 104 may interfere with the electrode assembly and compress the electrode assembly, this embodiment can raise the electrode assembly by setting the bottom support plate 40, thereby avoiding interference between the electrode assembly and the rounded corner structure 104 of the bottom wall 102 and improving the stability of the electrode assembly.

[0053] In conjunction with the above embodiments, such as Figure 5 As shown, the radius of the rounded corner structure 104 is r, the thickness of the base plate 40 is a, and the protrusion height b of the protrusion 401 satisfies: 0.2mm≤b≤ra. The base plate 40 is used to support the entire electrode assembly inside the housing 10 and can be used to form the exhaust channel 404. In this embodiment, by limiting the protrusion height of the protrusion 401, the exhaust channel 404 has sufficient space to allow the high-temperature and high-pressure gas to be discharged.

[0054] Specifically, the radius of the rounded corner structure 104 is greater than the thickness of the base plate 40, and by limiting b ≥ 0.2 mm, the minimum effective exhaust cross-sectional area of ​​the exhaust channel 404 is ensured, thereby achieving effective exhaust of the exhaust channel 404. Limiting b ≤ r – a ensures that a safe gap is maintained between the top of the protrusion and the rounded corner area of ​​the housing 10, avoiding interference between the electrode assembly and the rounded corner structure 104.

[0055] In conjunction with the above embodiments, such as Figure 5 As shown, the radius of the rounded corner structure 104 is 1.0mm ≤ r ≤ 2.5mm, and the thickness of the base plate 40 is 0.1mm ≤ a ≤ 0.3mm. The radius of the rounded corner structure 104 needs to be kept within a reasonable range; too large or too small a radius will affect the overall formation of the shell 10. Similarly, the thickness of the base plate 40 needs to be kept within a reasonable range; a base plate 40 that is too thin will be difficult to provide effective support, while a base plate that is too thick will occupy too much internal space of the shell 10, which is not conducive to the utilization of the internal space of the shell 10.

[0056] In a specific implementation, the radius r of the rounded corner structure 104 is 1.0mm, 1.2mm, 1.5mm, 1.8mm, 2.0mm, 2.3mm, or 2.5mm. The thickness a of the base plate 40 is 0.1mm, 0.15mm, 0.18mm, 0.2mm, 0.22mm, 0.25mm, or 0.3mm.

[0057] The following specific examples demonstrate a comparative test of the above-mentioned value range, and the test structure is shown in Table 1 below.

[0058] Table 1

[0059] As shown in the test table above, the thickness of the base plate 40 needs to be limited to the range of 0.1mm ≤ a ≤ 0.3mm. Exceeding this range will affect the overall support of the electrode assembly or the overall spatial layout. The height of the protrusion 401 needs to meet the requirement of 0.2mm ≤ b ≤ ra. If the height of the protrusion 401 does not fall within this range, it will affect the function of the exhaust channel 404 or occupy the internal space of the housing 10.

[0060] Through the above description of the embodiments, those skilled in the art can clearly understand that the protrusion 401 on the base plate 40 in each embodiment forms an exhaust channel 404 between the base plate 40 and the inner surface of the bottom wall 102 of the housing 10, thereby enabling rapid gas discharge in the event of thermal runaway and preventing the electrode assembly from clogging the pressure relief hole 103. Furthermore, by limiting the size of the protrusion height of the protrusion 401, the exhaust channel 404 can be ensured to be unobstructed, and the spatial layout can be made more reasonable.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A battery cell, characterized in that, include: The housing has an accommodating space for mounting electrode assemblies, and a pressure relief hole is provided on the bottom wall of the housing. A base plate is disposed between the bottom wall and the electrode assembly to support the electrode assembly; The bottom support plate has multiple protrusions on its surface facing the bottom wall, and the multiple protrusions are supported on the inner surface of the bottom wall, so that an exhaust channel is formed between the bottom support plate and the bottom wall. Furthermore, the exhaust passage is connected to the pressure relief hole.

2. The battery cell according to claim 1, characterized in that, The melting point Tm of the base plate is ≥250℃.

3. The battery cell according to claim 1, characterized in that, Multiple recessed grooves are provided on both sides near the width direction of the base plate, and the bottom of the recessed grooves protrudes to the side away from the electrode assembly to form the protrusion.

4. The battery cell according to claim 3, characterized in that, Each of the aforementioned sinks is provided with a through hole.

5. The battery cell according to claim 3, characterized in that, The edges of the trough opening and the bottom edge of the trough are both rounded.

6. The battery cell according to claim 3, characterized in that, The number of sinkholes located on both sides of the width direction of the bottom support plate is the same, and they are arranged side by side with intervals.

7. The battery cell according to claim 6, characterized in that, The pressure relief hole is located in the gap area between adjacent sinkers in the width direction of the bottom support plate.

8. The battery cell according to claim 3, characterized in that, The connection between the bottom wall and the inner sidewall of the shell has a rounded corner structure.

9. The battery cell according to claim 8, characterized in that, The radius of the rounded corner structure is r, the thickness of the base plate is a, and the protrusion height b of the protrusion satisfies: 0.2mm≤b≤ra.

10. The battery cell according to claim 9, characterized in that, The radius of the rounded corner structure is 1.0mm≤r≤2.5mm, and the thickness of the base plate is 0.1mm≤a≤0.3mm.

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