Battery cells, batteries and electrical devices

Abstract

This invention relates to the field of battery technology, specifically providing a battery cell, a battery, and an electrical device. The battery cell includes a casing, an electrode assembly, and terminals. The electrode assembly is housed within the casing and has tabs. The terminals are mounted on a first wall of the casing and include at least one first connecting portion and at least two second connecting portions. The first connecting portions are used to connect to an electrical connector, and the second connecting portions are used to connect to the tabs. A first connecting portion connects two adjacent second connecting portions. The bottom wall of the second connecting portion has a groove, which encloses a first region. Along the thickness direction of the bottom wall, the orthographic projection of the weld between the terminal and the tab falls into the first region. The groove is configured to disconnect the electrical connection between the tab and the terminal when the internal pressure of the casing exceeds a pressure threshold. This invention, by designing the groove to trigger an explosion when thermal runaway gas production reaches a pressure threshold, avoids the continuous current exacerbating the reaction and the transfer of heat along the conductive path, effectively controlling the risk of thermal runaway.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to a battery cell, a battery, and an electrical device. Background Technology

[0002] Factors such as internal short circuits, overcharging and over-discharging, and material aging can all cause thermal runaway in batteries. Violent chemical reactions occur inside the battery, and the temperature rises sharply, producing gas and increasing internal pressure. In severe cases, this can easily lead to fire or explosion.

[0003] In batteries or battery modules, individual battery cells are connected in series or parallel. Heat inside a battery cell can be transferred along the current path between the cell and adjacent cells, causing a fire to spread and triggering a series of chain reactions, posing a serious threat to the safety of battery use. Summary of the Invention

[0004] The battery cell, battery, and electrical device provided by the embodiments of the present invention at least solve the problems that the thermal runaway of the battery cell can easily lead to fire and explosion, and that the spread of heat along the current path poses a great safety hazard.

[0005] In a first aspect, embodiments of the present invention provide a battery cell comprising:

[0006] The outer casing has a first wall, and the first wall has a through hole along its thickness direction;

[0007] An electrode assembly having tabs, the electrode assembly being housed within the housing;

[0008] An electrode post is installed on the first wall. The electrode post includes at least one first connecting part and at least two second connecting parts. The first connecting part is used to connect with an electrical connector, and the second connecting parts are used to connect with the electrode tab. One first connecting part is connected between two adjacent second connecting parts.

[0009] The second connecting part includes a circumferential sidewall and a bottom wall, which together form a groove. A groove is formed on any side surface of the bottom wall along its thickness direction, and the groove encloses a first region. The second connecting part and the electrode tab are welded to form a welded part. The orthographic projection of the welded part falls into the first region along the thickness direction of the bottom wall. The groove is configured to disconnect the electrical connection between the electrode tab and the electrode post when the internal pressure of the housing exceeds a pressure threshold.

[0010] The battery cell provided in the embodiment of the present invention includes a circumferential sidewall comprising a first sidewall, a second sidewall, and a third sidewall connected in sequence, wherein the first sidewall and the third sidewall are disposed opposite to each other along the length direction of the first sidewall.

[0011] The groove includes a first groove segment, a second groove segment, and a third groove segment connected in sequence. The first groove segment is located near the first sidewall, the third groove segment is located near the third sidewall, and the second groove segment is located near the second sidewall. Along the width direction of the first wall, the second groove segment is connected to the end of the first groove segment and the third groove segment away from the first connecting part.

[0012] The battery cell provided in the embodiment of the present invention includes a groove that further includes a fourth groove segment and a fifth groove segment. The fourth groove segment is connected to the other end of the first groove segment, and the fifth groove segment is connected to the other end of the third groove segment. The fourth groove segment and the fifth groove segment extend towards each other along the length direction of the first wall.

[0013] Along the length of the first wall, the fourth and fifth groove segments are spaced apart, or the fourth and fifth groove segments are connected as one unit.

[0014] The battery cell provided in the embodiment of the present invention includes a tab comprising a welded section and a non-welded section. The welded section and the second connecting portion are welded to form the welded portion. Along the thickness direction of the bottom wall, the projection of the non-welded section at least partially overlaps with the first region.

[0015] The battery cell provided in the embodiment of the present invention has a distance L1 between the end of the first slot segment that is not connected to the second slot segment and the end of the third slot segment that is not connected to the second slot segment along the length direction of the first wall, and the length of the first connecting part is L2, wherein 70%L2≤L1≤L2; and / or, L2=10mm~50mm.

[0016] The battery cell provided in the embodiments of the present invention has a first groove segment that is arc-shaped, and / or a third groove segment that is arc-shaped, and / or a second groove segment that is straight.

[0017] The battery cell provided in the embodiment of the present invention has a distance of H1 between the bottom surface of the groove and the side surface of the bottom wall near the electrode assembly, and a thickness of H2 for the bottom wall, wherein H1 = (0.05~0.4)H2, and / or H2 ranges from 0.5 to 2 mm;

[0018] And / or, the minimum distance between the groove and the circumferential sidewall is L3, where L3 = 0-4 mm.

[0019] And / or, along the thickness direction of the first wall, the entire first region falls into the through hole.

[0020] In the battery cell provided by the present invention, the second connection portion is located on the side of the through hole away from the electrode assembly;

[0021] Alternatively, the second connecting portion may at least partially extend through the through hole.

[0022] Secondly, embodiments of the present invention also provide a battery comprising an electrical connector and at least two battery cells as described in any of the above embodiments, wherein the electrical connector connects a first connection portion of the terminals of two adjacent battery cells.

[0023] The battery provided in the present invention has an overlap between the first region of at least one of two adjacent battery cells and the orthographic projection of the electrical connector on a dummy plane perpendicular to the thickness direction of the first wall.

[0024] The battery provided in the present invention has an electrical connector that extends at least partially into the groove.

[0025] Thirdly, embodiments of the present invention also provide an electrical device comprising a battery cell as described in any of the above embodiments, or a battery as described in any of the above embodiments.

[0026] The battery cell, battery, and electrical device provided by this invention solve the problems of explosion and heat propagation after thermal runaway of a battery cell. By designing a grooved groove on the bottom wall of the second connection part of the battery cell terminal to form a weak structure, it can trigger an explosion when the pressure threshold is reached during thermal runaway gas generation, disconnecting the electrical connection between the tab and the terminal, preventing the continuous current from aggravating the reaction and the transfer of heat along the conductive path, effectively controlling the risk of thermal runaway. During the explosion, the high-pressure gas flow can also simultaneously cut off the connection between the electrical connector and the terminal, completely blocking the spread of heat between battery cells through metal components, improving the safety performance of the battery cell and the battery, without affecting the overcurrent capacity of the terminal and the high-rate charging and discharging of the battery. Attached Figure Description

[0027] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0028] Figure 1 This is a schematic diagram of the structure of a battery cell in Embodiment 1 of the present invention.

[0029] Figure 2 yes Figure 1 The cell shown is a cross-sectional view along the A-A' direction.

[0030] Figure 3 yes Figure 2 Enlarged diagram of point B in the middle.

[0031] Figure 4 yes Figure 1The diagram shows a partial isometric cross-section of a single battery cell along the A-A' direction.

[0032] Figure 5 yes Figure 1 The diagram shows the structural diagram of the electrode in a single battery cell.

[0033] Figure 6 yes Figure 5 The pole shown is an isometric sectional view along the D-D' direction.

[0034] Figure 7 yes Figure 6 Enlarged diagram of point E in the middle.

[0035] Figure 8 This is a schematic diagram of the structure of the first insulating element in Embodiment 1 of the present invention.

[0036] Figure 9 yes Figure 8 The first insulating element shown is an isometric sectional view along the F-F' direction.

[0037] Figure 10 This is a schematic diagram of the structure of the first wall in Embodiment 1 of the present invention.

[0038] Figure 11 This is a schematic diagram of the structure of the second insulating component and sealing component in Embodiment 1 of the present invention.

[0039] Figure 12 This is a schematic diagram of the structure of a battery in Embodiment 2 of the present invention.

[0040] Figure 13 yes Figure 12 The diagram shows the structure of the battery without electrical connectors.

[0041] Figure 14 yes Figure 12 The diagram shows the structure of the electrode assembly and the terminal block in the battery.

[0042] Figure 15 yes Figure 14 The electrode assembly and pole shown are partially cross-sectional views along the G-G' direction.

[0043] Figure 16 This is a schematic diagram of the structure of another battery cell in Embodiment 1 of the present invention.

[0044] Figure 17 yes Figure 16 The image shows a partial cross-sectional view of a single battery cell along the H-H' direction.

[0045] Figure 18 yes Figure 16 The image shows a partial isometric sectional view of a single battery cell along the H-H' direction.

[0046] Figure 19 yes Figure 16 The diagram shows the structural diagram of the electrode in a single battery cell.

[0047] Figure 20 yes Figure 19 The pole shown is a cross-sectional view along the I-I' direction.

[0048] Figure 21 yes Figure 19 The top view of the pole shown.

[0049] Figure 22 This is a top view of the pole post after the fourth and fifth slot sections are set in Embodiment 1 of the present invention.

[0050] Figure 23 This is a schematic diagram of the structure of another battery in Embodiment 2 of the present invention.

[0051] Figure 24 yes Figure 23 The diagram shows the structure of the electrical connectors in the battery.

[0052] Figure 25 yes Figure 23 The battery shown is a partial isometric sectional view along the J-J' direction.

[0053] Figure 26 yes Figure 25 A magnified view of point K in the middle.

[0054] Figure 27 This is a schematic diagram of the third type of pole in Embodiment 1 of the present invention.

[0055] The above figures include the following reference numerals:

[0056] 1. Outer shell; 11. First wall; 111. Through hole; 2. Electrode assembly; 21. Tab; 211. Welded section; 212. Non-welded section; 3. Terminal post; 4. First connecting part; 5. Second connecting part; 51. Circumferential side wall; 511. First side wall; 512. Second side wall; 513. Third side wall; 52. Bottom wall; 521. Scratched groove; 5211. First groove segment; 5212. Second groove segment; 5213. Third groove segment; 5214. Fourth groove segment; 5215. Fifth groove segment; 5216. Groove bottom surface; 53. First area; 54. Welded part; 6. Electrical connector; 61. Plug-in part; 7. Battery cell; 81. First insulating component; 82. Second insulating component; 83. Sealing ring; 9. Protective patch. Detailed Implementation

[0057] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0058] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0059] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0060] When thermal runaway or fire occurs inside a battery cell, the electrode materials and electrolyte react violently, rapidly releasing heat and a large amount of flammable gas. If components such as the tabs and terminals remain electrically connected, the continuous current will accelerate the rate of electrochemical reactions inside the battery, further generating heat and flammable gas. In addition, components such as the tabs and terminals will also experience rapid temperature rise due to electrical connections, causing circuit abnormalities and triggering a chain reaction in areas that were not yet out of control due to excessive temperature.

[0061] Therefore, Embodiment 1 of the present invention provides a battery cell 7, which includes a casing 1, an electrode assembly 2, and a terminal post 3. The battery cell 7 provided in Embodiment 1 has a weak point on the terminal post 3, which can disconnect the connection between the tab 21 and the terminal post 3 after thermal runaway and gas generation in the battery cell, avoiding the continuous transfer of heat along the electrical connection path, controlling the risk of thermal runaway, and improving the safety performance of the battery cell 7.

[0062] Specifically, refer to Figures 1-4 , Figure 10 and Figures 16-18 As shown, the outer shell 1 has a first wall 11, and the first wall 11 has a through hole 111 along its thickness direction. Figure 1 and Figure 16 All directions shown are referenced to the first wall 11. The length, height, and width directions in the diagram represent the length, height, and width directions of the first wall 11, and these directions are mutually perpendicular. As for... Figure 1 The corresponding sectional view, Figure 2 The thickness direction shown is the thickness direction of the first wall 11; as a parallel to... Figure 16 Corresponding partial sectional view, Figure 17 The thickness and width directions shown are also referenced to the first wall 11. In this embodiment, the outer casing 1 includes a shell and a top cover. The shell has an opening, and the top cover is fastened to the opening of the shell. The first wall 11 is the top cover. The electrode assembly 2 is housed in the shell, and the electrode assembly 2 has tabs 21 extending towards the top cover. In some other embodiments, the first wall 11 can also be any wall of the shell, such as the bottom wall of the shell.

[0063] Specifically, the terminal post 3 is mounted on the first wall 11 of the housing 1. The terminal post 3 includes at least one first connecting portion 4 and at least two second connecting portions 5. The first connecting portion 4 is used to connect with an electrical connector 6 to establish a circuit connection between the battery cell 7 and adjacent battery cells 7. The second connecting portions 5 are used to connect with a tab 21 to establish an electrical connection between the terminal post 3 of the battery cell 7 and the electrode assembly 2. (Refer to...) Figure 5 , Figure 6 , Figure 19 and Figure 27 As shown, a first connecting part 4 is connected between two adjacent second connecting parts 5.

[0064] When the battery cell 7 is in use, the current is drawn out from the tab 21 of the electrode assembly 2, and then flows through the second connection part 5 and the first connection part 4 of the pole post 3 in sequence through the electrical connection between the tab 21 and the second connection part 5. After that, the current flows from the pole post 3 to the electrical connection part 6 and other battery cells 7 through the connection between the first connection part 4 and the electrical connector 6.

[0065] Furthermore, referring to Figures 3-6 , Figures 17-20 As shown, the second connecting portion 5 includes a circumferential sidewall 51 and a bottom wall 52. The circumferential sidewall 51 connects to the outer edge of the bottom wall 52 and forms a groove with the bottom wall 52. In the thickness direction of the first wall 11, the circumferential sidewall 51 is disposed on the side of the bottom wall 52 away from the electrode assembly 2. The circumferential sidewall 51 is the groove sidewall of the groove, the bottom wall 52 is the closed side of the groove, and the open side of the groove is disposed away from the electrode assembly 2.

[0066] Reference Figure 4 , Figures 14-15 and Figure 26 As shown, the second connecting part 5 and the electrode lug 21 are welded together along the thickness direction of the bottom wall 52 to form a welded part 54. Figure 15The thickness direction shown is the thickness direction of the first wall 11. Figure 15 The width direction shown is the width direction of the first wall 11; in Embodiment 1 of the present invention, the thickness direction of the bottom wall 52 is consistent with the thickness direction of the first wall 11. A weak structure is provided on the bottom wall 52. When there is a safety hazard in the battery cell 7 and it reaches a certain limit, the weak structure is configured to disconnect the electrical connection between the tab 21 and the terminal post 3, specifically disconnecting the electrical connection between the tab 21 and the second connection part 5. By destroying the connection, the path of current conduction is cut off, thus avoiding the expansion of the thermal runaway range.

[0067] For example, the weak structure can be set as a specific area where the structural strength is controlled by changing the material, or the structural strength can be changed by setting the notched groove 521.

[0068] Preferably, refer to Figure 21 and Figure 22 As shown, a groove 521 is provided on the bottom wall 52 of the second connecting part 5, and the groove 521 encloses the first region 53. Figure 21 , Figure 22 The length direction shown is the length direction of the first wall 11. Figure 21 , Figure 22 The width direction shown is the width direction of the first wall 11. The pole post 3 itself can have various placement configurations in its top view, and the present invention... Figure 21 , Figure 22 The diagram shows a top view along the thickness direction of the first wall 11 when the electrode post 3 is installed inside the battery cell 7. Without the groove 521, the electrode post 3 is installed on the first wall 11 and the through-hole 111 of the first wall 11 is closed, placing the electrode assembly 2 in a sealed space. As electrochemical cycling causes gas production, the internal pressure changes are evenly distributed across the bottom wall 52. After machining the groove 521, the cross-sectional area at the location of the groove 521 is significantly reduced. When thermal runaway occurs internally, generating a large amount of gas, and the internal pressure continues to rise and act on the bottom wall 52, the stress concentration effect in the first region 53 enclosed by the groove 521 is more pronounced, and its maximum pressure threshold is lower than that of other intact regions of the bottom wall 52. Therefore, the groove 521 is configured to fracture or rupture preferentially compared to other regions of the bottom wall 52 and other locations on the outer casing 1 when the internal pressure of the outer casing 1 exceeds the pressure threshold, achieving a "detonation" effect. This serves as a preferred implementation of a weak structure to disconnect the electrical connection between the tab 21 and the electrode post 3.

[0069] The pressure threshold is related to the structural bearing capacity of the groove 521, which in turn is related to factors such as the etching depth, area, and extension length of the groove 521, the bottom wall material, the area of ​​the first region 53, the volume of the outer casing 1, and the utilization rate of the internal space. Therefore, the pressure threshold can be determined based on the actual safety requirements and manufacturing standards of the battery cell 7, and is not limited to a specific numerical value in Embodiment 1 of this invention.

[0070] It should be noted that the structural bearing capacity of all areas with the notched grooves 521 is consistent. By homogenizing the stress distribution and the pressure threshold that can be withstood, the consistency and synchronicity of the detonation of the first region 53 are achieved. If the depth of the notched grooves 521 varies, the shallower areas will have a larger cross-sectional area and higher structural strength, and can withstand a greater ultimate pressure, while the deeper areas will have a smaller cross-sectional area and lower strength, and will fracture earlier. When the depth of the notched grooves 521 is consistent, the internal pressure generated by thermal runaway can act synchronously on every part of the notched grooves 521, avoiding uneven stress distribution in local areas due to different stress concentrations. When the internal pressure exceeds the pressure threshold, the first region 53 can achieve synchronous fracture or rupture at the same time. This prevents premature detonation in some areas from causing insufficient pressure in other areas to fracture effectively, and also prevents delayed detonation in some areas from causing the internal pressure to accumulate and exceed the bearing capacity of the outer shell 1, leading to more dangerous situations such as shell rupture.

[0071] Specifically, in the thickness direction of the bottom wall 52, the scoring groove 521 can be provided on any side surface of the bottom wall 52. In some embodiments, the scoring groove 521 is provided on the side surface of the bottom wall 52 closer to the electrode assembly 2 in the thickness direction, and / or, on the side surface of the bottom wall 52 farther away from the electrode assembly 2 in the thickness direction. Here, the thickness direction refers to the thickness direction of the bottom wall 52. When the bottom wall 52 is arranged parallel to the first wall 11, its thickness direction is consistent with the thickness direction of the first wall 11.

[0072] Preferably, refer to Figure 6 and Figure 7 As shown, when the scoring groove 521 is only provided on the side surface of the bottom wall 52 away from the electrode assembly 2 in the thickness direction, the surface of the bottom wall 52 where the scoring groove 521 is provided and the surface of the welding tab 21 are two different sides in the thickness direction, which can avoid the influence of the welding tab 21 on the scoring groove 521, and thus facilitate the maintenance of the consistency of the scoring groove 521 bursting.

[0073] As an example, refer to Figure 7 and Figure 20As shown, the distance between the bottom surface 5216 of the groove 521 and the surface of the bottom wall 52 near the electrode assembly 2 is H1, the thickness of the bottom wall 52 is H2, and the maximum depth of the groove 521 along the thickness direction of the bottom wall 52 is H2-H1. Here, H1 is set to (0.05~0.4)H2, and / or 0.5mm≤H2≤2mm. When H1 is too small, the remaining thickness of the bottom wall 52 at the groove 521 position is too thin, making it prone to accidental damage due to insufficient structural strength when pressure changes or slight vibrations occur. It may even break before thermal runaway is triggered, leading to battery cell sealing failure or abnormal electrical connections. When H1 is too large, the groove 521 is too shallow, and the structural strength of the first region 53 is too high. When the battery cell experiences thermal runaway and generates gas pressure, it is difficult to burst open in time within the preset pressure threshold, easily causing casing cracking. Delayed bursting can also lead to the inability to quickly disconnect the electrical connection. In addition, if H2 is too small, the overall thickness of the bottom wall 52 is too thin, and the structural strength is still insufficient to support the mechanical load and air pressure changes under normal working conditions, which can easily lead to overall deformation or damage; if H2 is too large, it will increase the overall weight and space occupied by the pole post 3, which is not conducive to improving the energy density of the battery cell.

[0074] Specifically, refer to Figure 5 , Figure 19 and Figure 27 As shown, the circumferential sidewall 51 includes a first sidewall 511, a second sidewall 512, and a third sidewall 513 connected in sequence, along... Figure 16 Along the length of the first wall 11 shown, the first side wall 511 and the third side wall 513 are arranged opposite each other. One end of the second side wall 512 is connected to the first side wall 511, and the other end of the second side wall 512 is connected to the third side wall 513. Figure 16 The width direction of the first wall 11 is shown. The second side wall 512 connects the end of the first side wall 511 away from the first connecting part 4 and the end of the third side wall 513 away from the first connecting part 4. The length direction of the first wall 11 is perpendicular to the width direction, and the thickness direction of the first wall 11 is perpendicular to the plane containing the length and width directions.

[0075] In one implementation, reference is made to Figure 5 and Figure 21 As shown, the groove 521 includes a first groove segment 5211, a second groove segment 5212, and a third groove segment 5213 connected in sequence. The first groove segment 5211 is disposed near the first sidewall 511, the third groove segment 5213 is disposed near the third sidewall 513, and the second groove segment 5212 is disposed near the second sidewall 512. Along the width direction of the first wall 11, the second groove segment 5212 is connected to the end of the first groove segment 5211 and the third groove segment 5213 away from the first connecting portion 4.

[0076] Reference Figure 21As shown, along the width direction of the first wall 11, the end of the first groove segment 5211 near the first connecting portion 4 is a free end that is not connected to the second groove segment 5212, and the end of the third groove segment 5213 near the first connecting portion 4 is also a free end that is not connected to the second groove segment 5212. No scoring groove 521 is provided between the free ends of the first groove segment 5211 and the third groove segment 5213. In this embodiment, the scoring groove 521 is configured as an annular shape with an opening facing the first connecting portion 4. The area without the groove 521 is the current flow path between the second connection part 5 and the first connection part 4. The "C"-shaped opening of the groove 521 can avoid the overcurrent area. The non-closed annular groove 521 only forms a weak structure in the non-overcurrent area, keeping the structure intact and the overcurrent cross-sectional area unchanged at the overcurrent area, thus facilitating the maintenance of current flow efficiency. There is no structural weak point when the current flows through the connection of the first connection part 4 and the second connection part 5, avoiding affecting high-rate charging and discharging, and avoiding increased resistance, aggravated heating and decreased conductivity due to structural weakness.

[0077] Reference Figure 21 As shown, along the length of the first wall 11, the distance between the free end of the first groove segment 5211 that is not connected to the second groove segment 5212 and the free end of the third groove segment 5213 that is not connected to the second groove segment 5212 is L1, and the length of the first connecting part 4 is L2. 70% L2≤L1≤L2 is set, and / or 10mm≤L2≤50mm. L2 is preferably set to 20mm~35mm. If L2 is too small, it affects the current carrying capacity of the battery cell 7; if L2 is too large, it occupies more space and increases the volume and material cost of the terminal post 3. When L1=L2, the first groove segment 5211, the second groove segment 5212, and the third groove segment 5213 are respectively set to correspond to the first sidewall 511, the second sidewall 512, and the third sidewall 513. The unclosed area of ​​the groove 521 is consistent with the length of the first connecting part 4 and does not affect the current carrying capacity. If the L1 ratio is too small, the opening of the groove 521 will be too narrow, resulting in insufficient avoidance range. Part of the flow area will be covered by the groove 521, weakening the flow capacity. If the L1 ratio is too large, the opening will be too wide, which will affect the detonation of the first area 53 and make it difficult to detonate stably.

[0078] Reference Figure 5 , Figure 19 , Figure 21 and Figure 22 As shown, the first groove segment 5211 is arc-shaped, and / or the third groove segment 5213 is arc-shaped, and / or the second groove segment 5212 is straight. The scoring groove 521 is set as an unclosed elongated oval. The extension direction of the second groove segment 5212, the length direction of the first wall 11, and the length direction of the elongated oval are consistent. (Refer to...) Figure 27As shown, the first groove segment 5211, the second groove segment 5212 and the third groove segment 5213 can also be set according to the actual needs of the first region 53 and the welding part 54, as well as the shape of the circumferential sidewall 51. In addition to the unclosed oblong shape, the scoring groove 521 can also be set as a rectangle with an unclosed long side, or other irregular shapes.

[0079] Furthermore, in another embodiment, refer to Figure 22 As shown, the groove 521 includes a first groove segment 5211, a second groove segment 5212, and a third groove segment 5213; it also includes a fourth groove segment 5214 and a fifth groove segment 5215. The fourth groove segment 5214 is connected to the free end of the first groove segment 5211 that is not connected to the second groove segment 5212, and the fifth groove segment 5215 is connected to the free end of the third groove segment 5213 that is not connected to the second groove segment 5212. Along the length direction of the first wall 11, the fourth groove segment 5214 and the fifth groove segment 5215 are spaced apart, or they are connected as one piece. Preferably, the fourth groove segment 5214 and the fifth groove segment 5215 are straight.

[0080] When the fourth slot segment 5214 and the fifth slot segment 5215 are set at intervals, refer to Figure 22 As shown, the gap between the fourth slot segment 5214 and the fifth slot segment 5215 is the unclosed opening of the groove 521, and it is also oriented towards the first connecting part 4 to avoid affecting the high-rate charging and discharging to ensure overcurrent efficiency and overcurrent capacity. When the fourth slot segment 5214 and the fifth slot segment 5215 are connected as one piece, the groove 521 is a closed ring, and the first area 53 is a closed area, resulting in a better detonation effect.

[0081] Specifically, the welded portion 54 formed by welding the bottom wall 52 and the tab 21 has its orthographic projection falling into the first region 53. On the one hand, the orthographic projection of the weld falling into the first region 53 allows the internal air pressure to act more directly on the groove 521. The air pressure inside the outer shell 1 preferentially acts on the area where the welded portion 54 is located, and the area where the welded portion 54 is located is surrounded by the groove 521 in the orthographic projection of the first region 53. The pressure can be directly applied to the weak groove 521, improving the burst response efficiency of the groove 521 and avoiding burst delay or incomplete burst due to excessive pressure transmission path. At the same time, it can also avoid the situation where the projection of the welded portion 54 exceeds the range of the groove 521, resulting in local connection residues after burst. When bursting, the first region 53 will move as a whole into the groove, and the groove surrounded by the circumferential sidewall 51 provides a clearance space for the detonation of the first region 53. When the explosion occurs in the first area 53 of the bottom wall 52, the welded part 54 will detach from the tab 21 along with the structure, thereby disconnecting the electrical connection between the tab 21 and the terminal post 3, cutting off the path of heat transfer through the current, and ensuring the safety protection effect after thermal runaway inside the battery cell.

[0082] Reference Figure 15 As shown, in the extending direction of the bottom wall 52, the minimum distance between each segment of the groove 521 and the circumferential sidewall 51 is L3, where 0mm ≤ L3 ≤ 4mm. This minimum distance is the straight-line distance from the first groove segment 5211 to the corresponding point on the first sidewall 511, the second groove segment 5212 to the corresponding point on the second sidewall 512, and the third groove segment 5213 to the corresponding point on the third sidewall 513. Preferably, the gap width between the groove 521 and the circumferential sidewall 51 is consistent throughout, and the straight-line distance between the gap width and the corresponding point is the aforementioned minimum distance L3. When L3 is 0mm, the groove 521 is located at the edge of the bottom wall 52, connecting with the circumferential sidewall 51. If L3 is too large, it restricts the area of ​​the first region 53. Since the orthographic projection of the welding part 54 falls within the first region 53, an excessively large L3 will compress the size of the welding part 54, affecting the connection between the electrode assembly 2 and the electrode post 3.

[0083] Furthermore, referring to Figures 3-4 , Figures 14-15 and Figures 17-18 As shown, the tab 21 in the battery cell 7 is in a bent state. The tab 21 includes a welded section 211 and a non-welded section 212, which are welded together with the second connecting portion 5 to form a welded portion 54. The non-welded section 212 includes an extended area, a bent area, and other areas after bending that are not welded to the second connecting portion 5. Along the thickness direction of the bottom wall 52, the projection of the non-welded section 212 at least partially overlaps with the first region 53.

[0084] When the projection of the non-welded section 212 of the tab 21 falls entirely within the first region 53, the entire projection of the tab 21 is located within the first region 53. The tab 21 does not obstruct the groove 521, resulting in a better explosion effect in the first region 53. (Refer to...) Figure 15 As shown, when the projection of the non-welded section 212 partially overlaps with the first region 53, the first region 53 can also be blasted. Even though the blasting effect is slightly worse than that when the notch groove 521 is not blocked, the current can be cut off by detonating at least part of the connection of the tab 21 and by melting the tab 21 itself.

[0085] Reference Figure 3 , Figure 4 and Figures 8-11 As shown, the pole post 3 is installed on the first wall 11 of the housing 1, and the pole post 3 is insulated from the housing 1. A first insulating member 81 is provided on the outside of the pole post 3. The first insulating member 81 covers the surface of the pole post 3 and exposes at least the surface of the first connecting part 4 for connecting the electrical connector 6 and the surface of the second connecting part 5 for connecting the tab 21. The first insulating member 81 is provided through the second connecting part 5 in the thickness direction to avoid the airflow impact path.

[0086] In one embodiment of the present invention, the second connecting portion 5 is at least partially inserted into the through hole 111. (Refer to...) Figures 16-18 As shown, the welding section 211 of the tab 21 is located on the side of the through hole 111 near the electrode assembly 2. The battery cell 7 has higher space utilization and higher energy density in the thickness direction of the first wall 11.

[0087] In another embodiment of the first embodiment of the present invention, referring to Figures 1-4 , Figure 11 As shown, the second connecting portion 5 is located on the side of the through hole 111 away from the electrode assembly 2. A second insulating member 82 is provided on the side of the first wall 11 near the electrode assembly 2 in the thickness direction. The second insulating member 82 is used to insulate the electrode assembly 2 and the first wall 11, and a sealing ring 83 is also provided on the second insulating member 82. Since the second connecting portion 5 is located on the side of the through hole 111 away from the electrode assembly 2, in this embodiment, the tab 21 is led out and connected to the second connecting portion 5. Therefore, the second insulating member 82 is also provided on the inner wall of the through hole 111 for insulation from the tab 21.

[0088] It should be noted that when the second connecting part 5 is located on the side of the through hole 111 away from the electrode assembly 2, the projection of the first region 53 along the thickness direction of the first wall 11 falls entirely into the through hole 111. The gas inside the outer casing 1 can be guided out and released to the outside of the battery cell 7 through the through hole 111. At this time, the path of the airflow impacting and bursting the first region 53 is the shortest, reducing gas accumulation and lowering the risk of deformation and rupture of the first wall 11.

[0089] In Embodiment 1 of the present invention, the groove 521 on the electrode post 3 alters the structural strength of the first region 53, causing it to break when the internal pressure of the battery reaches a pressure threshold, thereby disconnecting the electrical connection between the tab 21 and the electrode post 3 and reducing the risk of safety accidents. Furthermore, the pressure release achieved by the groove 521 can also replace the explosion-proof valve structure in the battery cell 7, simplifying the design of the outer casing 1, saving design space for the first wall 11, and increasing the energy density of the battery cell 7.

[0090] Embodiment 2 of the present invention provides a battery, which includes an electrical connector 6 and at least two battery cells 7 provided in Embodiment 1 above. The electrical connector 6 connects the first connecting portion 4 of the terminals 3 of two adjacent battery cells 7, and the polarity of the two terminals 3 connected to the electrical connector 6 is opposite.

[0091] In a battery or battery module, when a single battery cell 7 experiences thermal runaway, even if thermal insulation material is placed between the casings of adjacent battery cells 7 to block heat transfer, heat will still continue to be transferred through conductive metal components such as tabs 21, terminals 3, and electrical connectors 6. Therefore, adjacent battery cells 7 also face the risk of thermal runaway. To address this, Embodiment 2 of the present invention provides a battery in which the battery cell 7 has a groove 521 on the terminal 3. When thermal runaway occurs and gas is generated, and the internal gas pressure reaches a preset threshold, the groove 521 breaks, causing the first region 53 to burst open, disconnecting the tabs 21 from the terminal 3. At the same time, it also cuts off the connection between the electrical connectors 6 and the terminal 3, completely blocking the path of heat transfer through the aforementioned conductive components and effectively preventing heat spread.

[0092] Specifically, each battery cell 7 has at least one first region 53 on its terminal post 3. Preferably, only one side of the second connection portion 5 on a terminal post 3 has the first region 53, which can avoid the risk of asynchronous detonation of the two first regions 53 due to processing tolerances, and ensure the reliability and safety of the triggering of the first region 53. During actual processing, the two grooves 521 may have tolerances due to factors such as equipment precision, material uniformity, and slight fluctuations in process parameters, resulting in differences in the depth, width, groove sharpness, or structural strength of the enclosed area of ​​the grooves 521. If both second connection portions 5 are provided with grooves 521, when high-pressure gas is generated by thermal runaway, the groove 521 with lower structural strength or more obvious stress concentration will explode first, while the other may explode later. Asynchronous detonation will cause the terminal post 3 to be unbalanced in force, and the first region 53 that explodes later may not completely break, or after breaking, it may not completely disconnect from the tab 21, thus leaving a conductive path and failing to effectively block heat transfer. Setting the first region 53 in only one second connection part 5 can overcome the risk of asynchronous detonation and simplify the structural design and processing flow, thereby improving the feasibility and stability of the scheme.

[0093] Furthermore, referring to Figure 12 , Figure 13 and Figures 23-25 As shown, on a virtual plane perpendicular to the thickness direction of the first wall 11, the orthographic projections of the first region 53 of at least one of two adjacent battery cells 7 overlap with those of the electrical connector 6. Based on the detonation of the first region 53, which breaks the connection between the tab 21 and the terminal post 3 of its own battery cell 7, the high-pressure airflow released at the moment of detonation impacts along the thickness direction of the first wall 11. Because the orthographic projections of the first region 53 of at least one battery cell 7 overlap with those of the electrical connector 6, the airflow can precisely act on the electrical connector 6 connecting the two battery cells 7. The impact force of the airflow breaks through the connection between the electrical connector 6 and the terminal post 3, thereby simultaneously severing the internal electrical connection of a single battery cell 7 and the external connection path formed between two adjacent battery cells 7 through the electrical connector 6. The detonation action of the first region 53 not only solves the safety problem of thermal runaway of a single battery cell 7 but also avoids the transfer of heat or current to adjacent battery cells 7 due to the continuous connection of the electrical connector 6, further reducing the risk of thermal runaway propagation.

[0094] Referring to the battery cell 7 provided in Embodiment 1, the second connecting portion 5 is located on the side of the through hole 111 away from the electrode assembly 2, or the second connecting portion 5 is at least partially inserted into the through hole 111.

[0095] Reference Figures 16-19 At least a portion of the second connecting part 5 shown is inserted into the through hole 111, as indicated by reference. Figures 23-26 As shown, at least a portion of the electrical connector 6 protrudes downward to form a plug portion 61 and extends into the groove of the second connecting portion 5. In the thickness direction of the first wall 11, the plug portion 61 of the electrical connector 6 can reduce the distance between the electrical connector 6 and the first region 53 that overlaps with the projection, shorten the channel length for the airflow to impact the electrical connector 6, and thus make it easier for the airflow when the first region 53 detonates to drive the electrical connector 6 to move together, resulting in a greater impact force on the electrical connector 6 and a better effect of the electrical connector 6 in cutting off the connection of adjacent battery cells 7.

[0096] Reference Figures 1-6 The second connecting part 5 shown is located on the side of the through hole 111 away from the electrode assembly 2, as indicated. Figure 12 As shown, the electrical connector 6 is configured as a planar plate structure. In the thickness direction of the first wall 11, when the electrical connector 6 abuts against the first connecting portion 4, there is a height difference between it and the bottom wall 52 of the second connecting portion 5. This height difference is related to the channel length through which the airflow impacts the electrical connector 6. Since the second connecting portion 5 does not extend into the through hole 111, the height difference is smaller than when the second connecting portion 5 is inserted into the through hole 111. Even without the insertion portion 61, the electrical connector 6 can still ensure sufficient impact force when the airflow impacts it, enough to cut off the connection between the electrical connector 6 and the terminal post 3, thereby preventing heat propagation between adjacent battery cells 7.

[0097] In some embodiments, when the second connecting portion 5 is located on the side of the through hole 111 away from the electrode assembly 2, refer to Figure 3 , Figure 4 and Figure 13 As shown, the battery is also equipped with a protective patch 9, which is located at the second connection portion 5. The first region 53, which overlaps with the electrical connector 6, is positioned opposite the protective patch 9 along the thickness direction of the first wall 11. The protective patch 9 is attached to the first insulating member 81 to seal the groove, preventing the scoring groove 521 and the first region 53 from being damaged by the outside of the battery cell 7 during transportation and other processes. When airflow impacts the electrical connector 6, the protective patch 9 is positioned in the airflow path and has minimal impact on the airflow impact force.

[0098] The battery provided in Embodiment 2 of the present invention can be detonated by damaging the groove 521 and the first region 53, which not only cuts off the electrical connection of the battery cell 7 itself, but also destroys the electrical connection between the electrical connector 6 and the terminal post 3, thereby controlling the thermal spread between adjacent battery cells 7. It is triggered only when the internal pressure exceeds the pressure threshold, thus mitigating the risk of thermal runaway while avoiding impact on power performance.

[0099] Embodiment 3 of the present invention provides an electrical device, which includes the battery cell 7 as provided in Embodiment 1 above, or the battery provided in Embodiment 2. Therefore, this electrical device incorporates all the technical effects of the aforementioned battery cell 7 or battery. Since the technical effects of the battery cell 7 and battery have already been described in detail above, they will not be repeated here.

[0100] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0101] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this application.

[0102] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A battery, characterized by, The battery comprises an electrical connector (6) and at least two battery cells (7). The battery cell (7) comprises: An outer shell (1) having a first wall (11) with a through hole (111) formed along a thickness direction thereof; An electrode assembly (2) having a tab (21), the electrode assembly (2) being accommodated in the outer shell (1); A post (3) mounted to the first wall (11), the post (3) comprising at least one first connecting portion (4) and at least two second connecting portions (5), the first connecting portion (4) being configured to connect with the electrical connector (6), the second connecting portions (5) being configured to connect with the tab (21), and one first connecting portion (4) being connected between two adjacent second connecting portions (5); The second connecting portion (5) comprises a circumferential side wall (51) and a bottom wall (52), the circumferential side wall (51) and the bottom wall (52) enclosing a groove, the bottom wall (52) being formed with a score groove (521) on any one side surface along a thickness direction thereof, the score groove (521) enclosing a first area (53), the second connecting portion (5) and the tab (21) being welded to form a welded portion (54), a projection of the welded portion (54) falling into the first area (53) along the thickness direction of the bottom wall (52), the score groove (521) being configured to disconnect the tab (21) and the post (3) when an internal pressure of the outer shell (1) exceeds a pressure threshold; The second connecting portion (5) is located on a side of the through hole (111) away from the electrode assembly (2), and a projection of the first area (53) falls into the through hole (111) along the thickness direction of the first wall (11); The electrical connector (6) connects the first connecting portions (4) of the posts (3) of two adjacent battery cells (7), and a projection of the first area (53) of at least one battery cell (7) and the electrical connector (6) overlap in a virtual plane perpendicular to the thickness direction of the first wall (11).

2. The battery of claim 1, wherein: The circumferential side wall (51) comprises a first side wall (511), a second side wall (512) and a third side wall (513) connected in sequence, and the first side wall (511) and the third side wall (513) are oppositely arranged along a length direction of the first wall (11). The score groove (521) comprises a first groove segment (5211), a second groove segment (5212) and a third groove segment (5213) connected in sequence, the first groove segment (5211) is arranged close to the first side wall (511), the third groove segment (5213) is arranged close to the third side wall (513), the second groove segment (5212) is arranged close to the second side wall (512), and the second groove segment (5212) is connected to one end of the first groove segment (5211) and the third groove segment (5213) away from the first connecting portion (4) along the width direction of the first wall (11).

3. The battery of claim 2, wherein: The score groove (521) further comprises a fourth groove segment (5214) and a fifth groove segment (5215), the fourth groove segment (5214) is connected to the other end of the first groove segment (5211), and the fifth groove segment (5215) is connected to the other end of the third groove segment (5213), the fourth groove segment (5214) and the fifth groove segment (5215) extend towards each other along the length direction of the first wall (11); The fourth groove segment (5214) and the fifth groove segment (5215) are arranged in a spaced manner along the length direction of the first wall (11), or the fourth groove segment (5214) and the fifth groove segment (5215) are connected as a whole.

4. The battery of claim 2, wherein, The tab (21) comprises a welding segment (211) and a non-welding segment (212), the welding segment (211) and the second connecting portion (5) are welded to form the welding portion (54), and the projection of the non-welding segment (212) at least partially overlaps the first area (53) along the thickness direction of the bottom wall (52).

5. The battery of claim 2, wherein, The distance between the end of the first groove segment (5211) not connected to the second groove segment (5212) and the end of the third groove segment (5213) not connected to the second groove segment (5212) along the length direction of the first wall (11) is L1, and the length of the first connecting portion (4) is L2, wherein 70%L2≤L1≤L2; and / or, L2=10mm~50mm.

6. The battery of claim 2, wherein, The first groove segment (5211) is arc-shaped, and / or the third groove segment (5213) is arc-shaped, and / or the second groove segment (5212) is linear.

7. The battery of any one of claims 1 to 6, wherein: When the score groove (521) is formed on the side surface of the bottom wall (52) away from the electrode assembly (2), the distance between the groove bottom surface (5216) of the score groove (521) and the side surface of the bottom wall (52) close to the electrode assembly (2) is H1, and the thickness of the bottom wall (52) is H2, wherein H1= (0.05~0.4)H2, and / or H2 ranges from 0.5 to 2mm; And / or, the minimum distance between the score groove (521) and the circumferential side wall (51) is L3, and L3=0-4mm.

8. The battery of claim 1, wherein, The electrical connecting member (6) at least partially extends into the recess.

9. An electrical device, characterized by A battery comprising the battery as claimed in any one of claims 1 to 8.

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