Top cover assembly, battery cell and battery device

Abstract

The invention discloses a top cover assembly, a battery cell and a battery device, the top cover assembly comprises: a cover plate, a positive pole electrically connected with the cover plate; the negative electrode module comprises a negative electrode pole, a negative electrode pressing plate, a short circuit piece and a first insulating plate, the short circuit piece is connected with the cover plate, and the short circuit piece is configured to make contact with the negative electrode pressing plate when the pressure in the containing cavity is larger than a preset value; and the blocking structure is configured to prevent the current of the positive pole from flowing to the negative pole through the cover plate when the negative pressing plate is electrically connected with the cover plate through the short circuit piece. According to the top cover assembly provided by the invention, when the single battery is overcharged, the positive pole and the negative pole can be short-circuited structurally, the charging loop of the single battery is switched, the charging loop of the battery device or the battery module is cut off, and the overcharge of the single battery is inhibited.

Description

Technical Field

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

[0002] With the rapid development of the new energy industry, lithium-ion batteries are widely used in electric vehicles, energy storage systems, and other fields due to their advantages such as high energy density and long cycle life. However, thermal runaway caused by overcharging of individual battery cells has become a core bottleneck restricting battery safety. During overcharging, violent chemical reactions occur inside the battery cell, releasing a large amount of heat and gas, which may eventually lead to fire and explosion.

[0003] Current battery cell structure designs do not include structural constraints for overcharge scenarios, requiring reliance on external BMS systems for power monitoring and protection. The safety of battery devices needs further improvement. Summary of the Invention

[0004] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the present invention provides a top cover assembly that can suppress overcharging of individual battery cells, disconnect the charging circuit of the battery device, and improve safety.

[0005] The present invention also proposes a battery cell having the above-described top cover assembly.

[0006] According to a first aspect of the present invention, a top cover assembly is used for a battery cell, the battery cell having a receiving cavity, comprising: a cover plate; a positive electrode module including a positive electrode post electrically connected to the cover plate; a negative electrode module including a negative electrode post, a negative electrode plate, a shorting member, and a first insulating plate, the negative electrode plate being connected to the negative electrode post and located on the side of the cover plate opposite to the receiving cavity, the shorting member being connected to the cover plate, the shorting member being configured to: contact the negative electrode plate when the pressure in the receiving cavity is greater than a preset value, and electrically connect the negative electrode plate to the cover plate through the shorting member; and a blocking structure disposed between the positive electrode post and the negative electrode post, the blocking structure being configured to prevent current from flowing from the positive electrode post to the negative electrode post through the cover plate when the negative electrode plate is electrically connected to the cover plate through the shorting member.

[0007] According to the top cover assembly of the present invention, by making the shorting member contact the negative electrode plate when the pressure in the receiving cavity is greater than a preset value, and by setting a blocking structure between the positive electrode post and the negative electrode post, the positive electrode post and the negative electrode post can be shorted structurally, switching the charging circuit of the battery cell, cutting off the charging circuit of the battery device or battery module, suppressing the overcharging of the battery cell, reducing the risk of thermal runaway or thermal runaway propagation, and without the need for complex control logic.

[0008] In some embodiments, the negative electrode plate includes a first fusible portion, which is configured to be fused when the negative electrode plate is electrically connected to the cover plate via the shorting member, and the first fusible portion forms the blocking structure.

[0009] In some embodiments, the current flow cross-sectional area of ​​the first fuse portion is 8 square millimeters to 30 square millimeters.

[0010] In some embodiments, the negative electrode plate includes a pressure ring portion and a shorting plate portion. The pressure ring portion is connected to the negative electrode post, and the shorting plate portion and the shorting member are directly opposite each other in the thickness direction of the cover plate. The shorting plate portion and the pressure ring portion are connected through the first fusible portion.

[0011] In some embodiments, the positive electrode module further includes a conductive sheet disposed on the side of the cover plate opposite to the receiving cavity and fixed to the cover plate, wherein the cover plate is electrically connected to the positive electrode post through the conductive sheet.

[0012] In some embodiments, the conductive sheet is annular and sleeved on the radially outer side of the positive electrode post, and is fixedly connected to the outer peripheral surface of the positive electrode post.

[0013] In some embodiments, the conductive sheet is a diode and is configured to allow current to flow unidirectionally from the cover plate toward the positive terminal, the conductive sheet being formed as the blocking structure.

[0014] In some embodiments, the top cover assembly further includes: a positive electrode connecting piece, the positive electrode connecting piece being connected to the positive electrode post and disposed on the side of the cover plate facing the receiving cavity, the positive electrode connecting piece having a second fusible portion, the second fusible portion being configured to be fused when the negative electrode pressure plate is electrically connected to the cover plate through the shorting member.

[0015] In some embodiments, the current flow cross-sectional area of ​​the second fuse is 8 square millimeters to 30 square millimeters.

[0016] In some embodiments, the negative electrode plate includes a first fusible portion, which is configured to be fused when the negative electrode plate is electrically connected to the cover plate through the shorting member. The first fusible portion forms the blocking structure, and the difference between the current flow cross-sectional area of ​​the second fusible portion and the first fusible portion is 0.5 mm² to 1 mm².

[0017] In some embodiments, the shorting member is an elastic member and is configured to elastically deform when the pressure in the receiving cavity is greater than a preset value, so as to contact the negative electrode plate.

[0018] In some embodiments, the preset value is 0.2MPa-0.6MPa, and / or the shorting connector and the negative electrode plate are directly opposite each other in the thickness direction of the cover plate, and the distance between the shorting connector and the negative electrode plate is 0.2mm-1mm.

[0019] In some embodiments, the preset value is 0.3MPa-0.4MPa; and / or, in the thickness direction of the cover plate, the distance between the shorting member and the negative electrode plate is 0.4mm-0.6mm.

[0020] In some embodiments, the shorting member includes: an elastic body and a protrusion, the elastic body being fixed to the cover plate, the protrusion being connected to the side of the elastic body facing the cover plate, and when the pressure on the shorting member is greater than a preset value, the elastic body undergoes elastic deformation to push the protrusion to contact the negative electrode pressure plate.

[0021] In some embodiments, the elastic body is in the form of an arcuate sheet protruding away from the cover plate, and the periphery of the elastic body is fixed to the cover plate.

[0022] In some embodiments, the outer contour of the elastic body is circular, and the outer diameter of the elastic body is 17mm-22mm; and / or, the protrusion is cylindrical, and the diameter of the protrusion is 5mm-10mm.

[0023] In some embodiments, a through hole is formed in the cover plate along the thickness direction of the cover plate, and the short connector is provided on the side of the cover plate away from the receiving cavity and seals the through hole.

[0024] In some embodiments, a recessed positioning groove is formed on the side surface of the cover plate opposite to the receiving cavity, the through hole is provided in the positioning groove and penetrates the bottom wall of the positioning groove, and the periphery of the short connector is fixed in the positioning groove.

[0025] In some embodiments, the top cover assembly further includes a second insulating plate disposed on the side of the cover facing the receiving cavity to separate the cover from the electrode assembly of the battery cell.

[0026] A battery cell according to a second aspect of the present invention includes: a housing defining a receiving cavity open on one side; an electrode assembly disposed within the receiving cavity; and a top cover assembly according to a first aspect of the present invention, the top cover being connected to the housing and sealing the open side of the receiving cavity.

[0027] According to the battery cell of the present invention, by providing the top cover assembly described in the first aspect, the overall performance of the battery cell is improved.

[0028] The battery device according to a third aspect of the present invention includes a battery cell according to a second aspect of the present invention.

[0029] According to the battery device of the present invention, by providing the battery cells described in the second aspect above, the overall performance of the battery device is improved.

[0030] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0031] Figure 1 This is an exploded view of the top cover assembly according to some embodiments of the present invention; Figure 2 yes Figure 1 The top cover assembly shown is a cross-sectional view at the location of the positive electrode module; Figure 3 yes Figure 1 The top cover assembly shown is a cross-sectional view at the location of the negative electrode module; Figure 4 yes Figure 1 The circuit diagram showing the electrical connections of the top cover assembly is shown. Figure 5 This is an exploded view of the top cover assembly according to other embodiments of the present invention; Figure 6 yes Figure 5 The top cover assembly shown is a cross-sectional view at the location of the positive electrode module; Figure 7 yes Figure 5 The top cover assembly shown is a cross-sectional view at the location of the negative electrode module; Figure 8 yes Figure 5 The circuit diagram showing the electrical connections of the top cover assembly is shown.

[0032] Figure label: 100. Top cover assembly; 10. Cover plate; 11. First pole post hole; 12. Second pole post hole; 13. Through hole; 14. Positioning groove; 15. Mounting hole; 20. Positive electrode module; 21. Positive electrode post; 211. First protruding edge; 22. Conductive sheet; 22a. Diode; 23. Positive electrode retaining ring; 24. First sealing ring; 30. Negative electrode module; 31. Negative electrode post; 311. Second convex edge; 32. Negative electrode pressure plate; 321. Pressure ring section; 322. Shorting plate section; 323. First fuse section; 33. Short connector; 331. Flexible body; 332. Protruding post; 34. First insulating plate; 35. Fastener; 36. Second sealing ring; 40. Positive electrode connector; 41. Second fuse part; 50. Negative electrode connector; 60. Second insulating board; 70. Explosion-proof valve; 80. Protective plate; 200. Electrode assembly. Detailed Implementation

[0033] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0034] The following is for reference. Figures 1-8 A top cover assembly 100 according to a first aspect embodiment of the present invention is described. The top cover assembly 100 is used for a battery cell, the battery cell including a housing and an electrode assembly 200. The housing defines a top-open receiving cavity, the top cover assembly 100 covers the open side of the receiving cavity, the electrode assembly 200 is disposed in the receiving cavity, and a positive electrode post 21 and a negative electrode post 31 on the top cover assembly 100 are respectively connected to the positive electrode plate and the negative electrode plate of the electrode assembly 200.

[0035] like Figure 1 As shown, the top cover assembly 100 according to a first aspect embodiment of the present invention includes: a cover plate 10, a positive electrode module 20, a negative electrode module 30, and a blocking structure.

[0036] Specifically, the positive electrode module 20 includes a positive electrode post 21, which is electrically connected to the cover plate 10; the negative electrode module 30 includes a negative electrode post 31, a negative electrode pressure plate 32, a shorting connector 33, and a first insulating plate 34. The negative electrode pressure plate 32 is located on the side of the cover plate 10 away from the receiving cavity in the thickness direction and is connected to the negative electrode post 31, and is located on the side of the cover plate 10 away from the receiving cavity. The first insulating plate 34 is arranged between the negative electrode pressure plate 32 and the cover plate 10. The shorting connector... The shorting member 33 is fixed to the cover plate 10. The shorting member 33 is configured to contact the negative electrode plate 32 when the pressure in the cavity of the battery cell is greater than a preset value, and to make the negative electrode plate 32 electrically connected to the cover plate 10 through the shorting member 33. The blocking structure is provided between the positive electrode post 21 and the negative electrode post 31. The blocking structure is configured to prevent the current of the positive electrode post 21 from flowing through the cover plate 10 to the negative electrode post 31 when the negative electrode plate 32 is electrically connected to the cover plate 10 through the shorting member 33.

[0037] like Figure 1As shown, the cover plate 10 is a rectangular plate with its length along the left-right direction and its thickness along the up-down direction. The cover plate 10 is made of aluminum. A first pole hole 11 and a second pole hole 12 are formed on the cover plate 10, which extend through the cover plate 10 in the up-down direction. The first pole hole 11 and the second pole hole 12 are spaced apart in the left-right direction.

[0038] The positive electrode post 21 extends in a cylindrical shape along the vertical direction. The lower end of the positive electrode post 21 is provided with a first protruding edge 211 extending radially outward. The first protruding edge 211 extends in a ring shape along the circumference of the positive electrode post 21. The upper end of the positive electrode post 21 extends from bottom to top through the first electrode post hole 11 to the top of the cover plate 10. The lower end of the positive electrode post 21 is suitable for connecting to the positive electrode of the electrode assembly 200. For example, the positive electrode post 21 is connected to the positive electrode tab of the electrode assembly 200 through the positive electrode connecting piece 40.

[0039] The negative electrode post 31 extends in a cylindrical shape along the vertical direction. The lower end of the negative electrode post 31 is provided with a second convex edge 311 extending radially outward. The second convex edge 311 extends in a ring shape along the circumference of the negative electrode post 31. The upper end of the negative electrode post 31 extends from bottom to top through the second electrode post hole 12 to the top of the cover plate 10. The lower end of the negative electrode post 31 is suitable for connecting to the negative electrode of the electrode assembly 200. For example, the negative electrode post 31 is connected to the negative electrode tab of the electrode assembly 200 through the negative electrode connecting piece 50.

[0040] In some examples, the positive terminal 21 can be directly connected to the cover plate 10 to achieve an electrical connection between the cover plate 10 and the positive terminal 21. The positive terminal 21 can also be indirectly connected to the cover plate 10 through other conductive elements, such as the positive terminal 21 being electrically connected to the cover plate 10 through the conductive sheet 22 or diode 22a described below.

[0041] The negative electrode plate 32 is made of conductive material. The negative electrode plate 32 is located on the upper side of the cover plate 10 and is sleeved on the outside of the negative electrode post 31 to achieve fixation and electrical connection with the negative electrode post 31.

[0042] The first insulating plate 34 is disposed between the negative electrode post 31 and the cover plate 10, and between the negative electrode pressure plate 32 and the cover plate 10. The first insulating plate 34 is a plastic part. By setting the first insulating plate 34, the negative electrode post 31 and the cover plate 10, and the negative electrode pressure plate 32 and the cover plate 10, can maintain insulation during normal charging and discharging of the battery cell, avoiding the risk of short circuit.

[0043] In some examples, the shorting element 33 can be an elastic element capable of elastic deformation, or it can be a heat-deformable element. When the shorting element 33 undergoes elastic or heat deformation, it comes into contact with the negative electrode plate 32, thereby achieving a conductive connection between the positive electrode post 21 and the negative electrode post 31 through the cover plate 10.

[0044] When a battery cell is operating normally, the air pressure inside the containment cavity is within a preset range. At this time, there is a gap between the shorting connector 33 and the negative electrode plate 32, and they are not conductive, allowing the battery cell to charge and discharge normally. When the pressure inside the containment cavity of the battery cell abnormally rises to a preset value, the shorting connector 33 contacts the negative electrode plate 32. At this time, the positive electrode post 21 is connected to the negative electrode post 31 through the cover plate 10, the shorting connector 33, and the negative electrode plate 32 in sequence, thus short-circuiting the positive and negative electrodes of the battery cell. This fuses the fuse structure in the short-circuit circuit (such as the second fuse part 41, the first fuse part 323, or other narrow-aperture structures described below), thereby cutting off the charging circuit of the battery cell, preventing overcharging of the battery cell, and reducing the risk of thermal runaway or thermal runaway propagation.

[0045] Furthermore, when the positive electrode post 21 and the negative electrode post 31 are short-circuited through the negative electrode pressure plate 32, the shorting member 33 and the cover plate 10, the internal fuse structure of the battery cell can be quickly melted, thereby blocking the current path between the positive electrode post 21 and the positive electrode plate of the electrode assembly 200, thus disconnecting the charging circuit of the battery cell.

[0046] It should be noted that during the charging process of a single battery cell, current enters the cell from the positive terminal 21, passes through the electrode assembly, and then flows out of the cell from the negative terminal 31. The battery device comprises multiple battery cells, which can form one or more battery modules. In a battery module, multiple battery cells are connected in series. During charging, current enters the electrode assembly from the positive terminal 21 of one battery cell and flows out from the negative terminal 31, then enters the next battery cell from the positive terminal 21 of the next battery cell. If an overcharged battery cell is only disconnected, the battery device still faces the risk of thermal runaway.

[0047] Therefore, in this embodiment, when the positive terminal 21 and the negative terminal 31 are short-circuited through the negative terminal plate 32, the shorting member 33 and the cover plate 10, the blocking structure can prevent the current of the positive terminal 21 from flowing through the cover plate 10 to the negative terminal 31. For example, the blocking structure can be melted when the positive terminal 21 and the negative terminal 31 are short-circuited through the negative terminal plate 32, the shorting member 33 and the cover plate 10, thereby disconnecting the positive terminal 21 and the negative terminal 31 in the circuit connected through the cover plate 10. Alternatively, the blocking structure can only allow the current from the negative terminal 31 to flow through the cover plate 10 to the positive terminal 21, and prevent the current from flowing from the positive terminal 21 to the negative terminal 31 through the cover plate 10.

[0048] In this way, the blocking structure can prevent the charging current of the battery device or battery module from flowing directly to the next battery cell through the positive terminal 21, cover plate 10, and negative terminal 31. That is, the blocking structure can prevent the positive terminal 21, cover plate 10, and negative terminal 31 from being short-circuited and used as a conductive structure to directly connect two adjacent battery cells. Thus, the blocking structure can prevent the current in the charging circuit of the battery device or battery module from continuing to conduct in the direction of charging current through the short-circuited conductive structure (positive terminal → cover plate → negative terminal) of the thermally runaway or overcharged battery cell. In this embodiment, the charging circuit of the battery module or battery device can be cut off between the positive and negative terminals of the top cover assembly, thereby cutting off the charging circuit of the battery device or battery module and further ensuring the safety of the battery device.

[0049] According to the embodiments of the present invention, the top cover assembly 100 can make the shorting member 33 contact the negative electrode plate 32 when the pressure in the receiving cavity is greater than a preset value, and provide a blocking structure between the positive electrode post 21 and the negative electrode post 31. This can structurally short-circuit the positive electrode post 21 and the negative electrode post 31, switch the charging circuit of the battery cell, and use the blocking structure to cut off the charging circuit of the battery device or battery module, suppress the overcharging of the battery cell, reduce the risk of thermal runaway or thermal runaway propagation, and eliminate the need for complex control logic.

[0050] In some embodiments of the present invention, such as Figure 1 As shown, the negative electrode plate 32 includes a first fusible part 323, which is formed as a blocking structure and is configured to be fused when the negative electrode plate 32 is electrically connected to the cover plate 10 through the shorting member 33.

[0051] In this way, when the positive terminal 21 and the negative terminal 31 are shorted through the negative terminal plate 32, the shorting member 33 and the cover plate 10, the negative terminal plate 32 can be quickly melted at the first fuse part 323, thereby preventing the current in the charging circuit of the battery device or battery module from being connected to the cover plate 10 and the positive terminal 21 through the negative terminal 31, thereby further ensuring the safety of the battery device.

[0052] In some embodiments of the present invention, such as Figure 1As shown, the current flow cross-sectional area of ​​the first fuse portion 323 is 8 square millimeters to 30 square millimeters. For example, the current flow cross-sectional area of ​​the first fuse portion 323 can be 8 square millimeters, 10 square millimeters, 12 square millimeters, 14 square millimeters, 16 square millimeters, 18 square millimeters, 20 square millimeters, 22 square millimeters, 24 square millimeters, 26 square millimeters, 28 square millimeters, or 30 square millimeters. By making the current flow cross-sectional area of ​​the first fuse portion 323 greater than or equal to 8 square millimeters, the first fuse portion 323 can meet the normal charging and discharging current requirements of the battery cell, avoiding excessive heating under normal charging and discharging conditions and improving charging efficiency. By making the current flow cross-sectional area of ​​the first fuse portion 323 less than or equal to 30 square millimeters, the first fuse portion 323 can fuse quickly, reducing response time, timely blocking the current path, and reducing the risk of thermal runaway.

[0053] In some embodiments of the present invention, such as Figure 1 As shown, the current flow cross-sectional area of ​​the first fuse portion 323 is 10-20 square millimeters; for example, the current flow cross-sectional area of ​​the first fuse portion 323 can be 11, 13, 15, 17, 19, or 20 square millimeters. This further improves charging efficiency, further reduces the response time when a battery cell is overcharged, promptly blocks the current path, and reduces the risk of thermal runaway.

[0054] In some embodiments of the present invention, such as Figure 1 As shown, the negative electrode plate 32 includes a pressure ring portion 321 and a shorting plate portion 322. The pressure ring portion 321 is connected to the negative electrode post 31, and the shorting plate portion 322 and the shorting member 33 are directly opposite each other in the thickness direction of the cover plate 10. The shorting plate portion 322 and the pressure ring portion 321 are connected through a first fusible part 323. Thus, when the shorting member 33 undergoes elastic deformation, it can sequentially connect to the negative electrode post 31 through the shorting plate portion 322, the first fusible part 323, and the pressure ring portion 321, ensuring that the positive electrode post 21 and the negative electrode post 31 can be smoothly short-circuited, thereby timely cutting off the charging circuit inside the battery cell and the charging circuit of the battery module.

[0055] In some examples, the shorting plate portion 322, the first fusion portion 323, and the pressure ring portion 321 are arranged sequentially and connected along the length of the cover plate 10. This allows for a compact structure.

[0056] In some embodiments of the present invention, such as Figure 1 , Figure 2 , Figure 5 and Figure 6As shown, the positive electrode module 20 further includes a conductive sheet 22, which is arranged on the side of the cover plate 10 away from the receiving cavity and fixed to the cover plate 10. The cover plate 10 is electrically connected to the positive electrode post 21 through the conductive sheet 22. The conductive sheet 22 can be a stainless steel sheet, and it abuts against the cover plate 10 in the thickness direction of the cover plate 10. Therefore, a stable contact resistance can be formed between the conductive sheet 22 and the cover plate 10, which stabilizes the current and achieves a reliable electrical connection between the positive electrode post 21 and the cover plate 10.

[0057] In some embodiments of the present invention, such as Figure 1 and Figure 2 As shown, the conductive sheet 22 is annular and sleeved on the radial outer side of the positive electrode post 21, and is fixedly connected to the outer circumferential surface of the positive electrode post 21. This simplifies the structure of the conductive sheet 22 and makes the positive electrode post 21 uniformly connected to the cover plate 10 in the circumferential direction through the conductive sheet 22, thereby improving the stability and reliability of the electrical connection.

[0058] In some embodiments of the present invention, such as Figure 5 , Figure 6 and Figure 8 As shown, the conductive sheet 22 is a diode 22a. The conductive sheet 22 is formed as a blocking structure and is configured to allow current to flow unidirectionally from the cover plate 10 towards the positive terminal 21. Thus, when the pressure inside the battery cell abnormally increases, the positive terminal 21 and the negative terminal 31 are short-circuited, forming a large current. This can cause the second fuse 41 on the positive terminal connector 40 to melt, thereby switching the charging circuit of the battery cell. Simultaneously, when current in the charging circuit of the battery device enters the battery cell from the positive terminal 21, the diode 22a can prevent the current from flowing from the positive terminal 21 through the cover plate 10 and the negative terminal plate 32 to the negative terminal 31, thereby disconnecting the charging circuit of the battery device and reducing safety risks.

[0059] In some examples, diode 22a is a fast recovery diode (FRD). A fast recovery diode 22a is a semiconductor device with fast reverse recovery characteristics. It employs a PIN structure design to reduce stored charge, shortening the reverse recovery time to tens to hundreds of nanoseconds. This allows for rapid interruption of reverse current.

[0060] In some embodiments of the present invention, such as Figure 1 As shown, the top cover assembly 100 may further include a positive electrode connecting piece 40, which is connected to the positive electrode post 21 and is disposed on the side of the cover plate 10 facing the receiving cavity. The positive electrode connecting piece 40 is used to connect the positive electrode tab of the electrode assembly 200. The positive electrode connecting piece 40 has a second fusible part 41, which is configured to be fused when the negative electrode pressure plate 32 is electrically connected to the cover plate 10 through the shorting member 33.

[0061] This embodiment provides a second fuse 41 on the positive electrode connector 40, which can shorten the protection delay and improve the timeliness of safety protection while conveniently and effectively cutting off the charging circuit inside the battery cell. It also eliminates the need for additional fuse components, reducing the space occupied inside the battery cell.

[0062] In some embodiments of the present invention, such as Figure 1 and Figure 5 As shown, the current flow cross-sectional area of ​​the second fuse portion 41 is 8 square millimeters to 30 square millimeters; for example, the current flow cross-sectional area of ​​the second fuse portion 41 can be 8 square millimeters, 10 square millimeters, 12 square millimeters, 14 square millimeters, 16 square millimeters, 18 square millimeters, 20 square millimeters, 22 square millimeters, 24 square millimeters, 26 square millimeters, 28 square millimeters, or 30 square millimeters. By making the current flow cross-sectional area of ​​the second fuse portion 41 greater than or equal to 8 square millimeters, the second fuse portion 41 can meet the normal charging and discharging current requirements of the battery cell, avoid excessive heating under normal charging and discharging conditions, and improve charging efficiency. By making the current flow cross-sectional area of ​​the second fuse portion 41 less than or equal to 30 square millimeters, the second fuse portion 41 can fuse quickly, reduce response time, promptly block the current path, and reduce the risk of thermal runaway.

[0063] In some embodiments of the present invention, such as Figure 1 and Figure 5 As shown, the current flow cross-sectional area of ​​the second fuse section 41 is 10-20 square millimeters; for example, the current flow cross-sectional area of ​​the second fuse section 41 can be 11, 13, 15, 17, 19, or 20 square millimeters. This further improves charging efficiency, further reduces the response time when a battery cell is overcharged, promptly blocks the current path, and reduces the risk of thermal runaway.

[0064] In some embodiments of the present invention, such as Figure 1As shown, the negative electrode plate 32 includes a first fusible portion 323, which is formed as a blocking structure and is configured to melt when the negative electrode plate 32 is electrically connected to the cover plate 10 via a shorting member 33. The difference in current flow cross-sectional area between the second fusible portion 41 and the first fusible portion 323 is 0.5 square millimeters to 1 square millimeter. For example, the difference in current flow cross-sectional area between the second fusible portion 41 and the first fusible portion 323 can be 0.5 square millimeters, 0.6 square millimeters, 0.7 square millimeters, 0.8 square millimeters, 0.9 square millimeters, or 1 square millimeter. Thus, the current flow cross-sectional areas of the second fusible portion 41 and the first fusible portion 323 can be controlled within a small difference range. When the internal pressure of the battery cell increases to a preset value, the positive electrode post 21 and the negative electrode post 31 are short-circuited, so that the second fusible portion 41 and the first fusible portion 323 can melt almost simultaneously, cutting off the current path and further reducing the risk of thermal runaway.

[0065] It should be noted that since the second fuse part 41 is arranged inside the casing of the battery cell, it generates more heat. Therefore, in some examples, the current flow cross-sectional area of ​​the second fuse part 41 is larger than that of the first fuse part 323.

[0066] In some embodiments of the present invention, the preset value is 0.2MPa-0.6MPa. That is, when the pressure inside the cavity is 0.2MPa-0.6MPa, the shorting member 33 undergoes elastic deformation and abuts against the negative electrode plate 32, short-circuiting the positive electrode post 21 and the negative electrode post 31. For example, the preset pressure value can be 0.2MPa, 0.25MPa, 0.3MPa, 0.35MPa, 0.4MPa, 0.45MPa, 0.5MPa, 0.55MPa, or 0.6MPa.

[0067] By setting the preset pressure inside the containment cavity to be greater than or equal to 0.2 MPa, accidental melting can be avoided under conditions such as bumpy roads or slight gas generation during fast charging, ensuring the stability of the battery cell. By setting the preset pressure to be less than or equal to 0.6 MPa, the response time can be shortened, and the pressure inside the containment cavity can be prevented from exceeding the pressure threshold of the battery cell's casing, reducing the risk of thermal runaway and the risk of thermal propagation.

[0068] Furthermore, the preset value is 0.3MPa-0.4MPa. For example, the preset value can be 0.3MPa, 0.31MPa, 0.32MPa, 0.33MPa, 0.34MPa, 0.35MPa, 0.36MPa, 0.37MPa, 0.38MPa, 0.39MPa, or 0.4MPa. This can further avoid the risk of the shorting device 33 being accidentally triggered, improve the stability of the battery cell, and further reduce the response time of the shorting device 33, thereby reducing the risk of thermal runaway and thermal propagation.

[0069] In some embodiments of the present invention, the shorting member 33 is an elastic member and is configured to elastically deform when the pressure within the receiving cavity exceeds a preset value, thereby contacting the negative electrode plate 32 and electrically connecting the negative electrode plate 32 to the cover plate 10 via the elastic member. For example, the shorting member 33 may be along the thickness direction of the cover plate 10 (e.g., along the thickness direction of the cover plate 10). Figure 3 The elastic element (shown in the up-down direction) is capable of elastic deformation. When the battery cell is operating normally, the air pressure inside the cavity is within a preset range. At this time, there is a gap between the elastic element and the negative electrode plate 32 in the thickness direction of the cover plate 10, and they are not conductive, allowing the battery cell to charge and discharge normally. When the pressure inside the battery cell cavity abnormally rises to a preset value, the elastic element deforms along the thickness direction of the cover plate 10 towards the side where the negative electrode plate 32 is located, and comes into contact with the negative electrode plate 32. At this time, the negative electrode plate 32 is electrically connected to the cover plate 10 through the elastic element. In this embodiment, by setting the shorting element 33 as an elastic element, the structure of the shorting element 33 can be simplified, costs reduced, and space occupied reduced.

[0070] like Figure 3 As shown, when the pressure inside the housing of a battery cell abnormally rises to a preset value, since the top cover assembly 100 is arranged at the top of the housing of the battery cell, when the air pressure in the housing acts on the top cover assembly 100, the elastic element is subjected to pressure along the... Figure 3 The force shown is in the upward direction, and this force is along... Figure 3 The elastic element shown is pushed upwards and deformed toward the side where the negative electrode plate 32 is located, so that the elastic element abuts against the negative electrode plate 32, thereby realizing the electrical connection between the negative electrode plate 32 and the cover plate 10 through the elastic element.

[0071] In some embodiments of the present invention, the shorting member 33 and the negative electrode plate 32 are directly opposite each other in the thickness direction of the cover plate 10, and the distance between the shorting member 33 and the negative electrode plate 32 is 0.2mm-1mm. For example, the distance between the shorting member 33 and the negative electrode plate 32 can be 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm or 1mm. In this embodiment, by making the distance between the shorting member 33 and the negative electrode plate 32 greater than or equal to 0.2mm, it can avoid the shorting member 33 accidentally touching the negative electrode plate 32 under conditions such as bumpy road conditions or slight gas generation during fast charging, thus ensuring the stability of the battery cell. By making the distance between the shorting member 33 and the negative electrode plate 32 less than or equal to 1mm, it can be ensured that the shorting member 33 can effectively abut against the negative electrode plate 32 when deformation occurs, ensuring the reliability of the shorting, and shortening the time for the shorting member 33 to deform, thus shortening the response time and reducing the risk of thermal runaway.

[0072] Furthermore, in the thickness direction of the cover plate 10, the distance between the shorting member 33 and the negative electrode plate 32 is 0.4mm-0.6mm. For example, the distance between the shorting member 33 and the negative electrode plate 32 can be 0.4mm, 0.45mm, 0.5mm, 0.55mm, or 0.6mm. This avoids the problem of the shorting member 33 accidentally contacting the negative electrode plate 32, ensuring the stability of the battery cell, reducing the deformation distance of the shorting member 33, shortening the deformation time of the shorting member 33, shortening the response time, and reducing the risk of thermal runaway.

[0073] In some embodiments of the present invention, such as Figure 3 and Figure 7 As shown, the shorting connector 33 includes an elastic body 331 and a protrusion 332. The elastic body 331 is fixed to the cover plate 10, and the protrusion 332 is connected to the side of the elastic body 331 facing the cover plate 10. When the pressure on the shorting connector 33 is greater than a preset value, the elastic body 331 undergoes elastic deformation to push the protrusion 332 to contact the negative electrode pressure plate 32.

[0074] In this embodiment, by setting a protrusion 332 for contact with the negative electrode plate 32, the reliability of the contact between the shorting piece 33 and the negative electrode plate 32 can be guaranteed.

[0075] In some embodiments of the present invention, such as Figure 3 and Figure 7 As shown, the elastic body 331 is an arc-shaped sheet protruding away from the cover plate 10, and the periphery of the elastic body 331 is fixed to the cover plate 10. For example, the short connector 33 is a single piece, the elastic body 331 is a sheet with a spherical or ellipsoidal surface protruding downwards, the protruding post 332 is a column extending in the vertical direction, the lower end of the protruding post 332 is connected to the elastic body 331, and the upper end of the protruding post 332 extends beyond the upper edge (outer periphery) of the elastic body 331 in the vertical direction.

[0076] In this embodiment, by setting an elastic body 331 that protrudes along the arc surface on the side where the receiving cavity is located, the elastic body 331 can easily deform towards the negative electrode pressure plate 32 under the pressure in the receiving cavity, simplifying the structure of the short connector 33 and making it convenient for the short connector 33 to respond in time when the pressure in the receiving cavity reaches the preset value.

[0077] In some embodiments of the present invention, such as Figure 3 and Figure 7As shown, the outer contour of the elastic body 331 is circular, and the outer diameter of the elastic body 331 is 17mm-22mm; for example, the outer diameter of the elastic body 331 can be 17mm, 18mm, 19mm, 20mm, 21mm, or 22mm. Further, the outer diameter of the elastic body 331 is 22mm, and the periphery of the elastic body 331 can be welded to the cover plate 10. In this embodiment, by making the outer diameter of the elastic body 331 greater than or equal to 17mm and less than or equal to 22mm, not only can the welding length between the elastic body 331 and the cover plate 10 be reduced, avoiding welding defects that could lead to poor airtightness at the through hole 13, but the shortening member can also have sufficient deformation, allowing for a timely and accurate response when the pressure inside the cavity reaches a preset value.

[0078] In some embodiments of the present invention, such as Figure 3 and Figure 7 As shown, the protrusion 332 is cylindrical in shape, and its diameter is 5mm-10mm. More specifically, the diameter of the protrusion 332 is 7mm-8mm. For example, the diameter of the protrusion 332 can be 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, or 10mm. In this embodiment, by making the diameter of the protrusion 332 less than or equal to 10mm, the contact area between the protrusion 332 and the negative electrode plate 32 can be reduced, facilitating the formation of a weld at the contact point. By making the diameter of the protrusion 332 greater than or equal to 5mm, the connection strength of the weld between the protrusion 332 and the negative electrode plate 32 can be guaranteed.

[0079] In some embodiments of the present invention, such as Figure 1 and Figure 3 As shown, a square through hole 13 extending through the thickness of the cover plate 10 is formed on the cover plate 10. A short connector 33 is disposed on the side of the cover plate 10 away from the receiving cavity. The short connector 33 is fixed to the cover plate 10 and seals the through hole 13. In this embodiment, by fixing the short connector 33 to the position of the through hole 13 of the cover plate 10 and sealing the through hole 13, the sealing performance of the through hole 13 position can be guaranteed.

[0080] In some embodiments of the present invention, such as Figure 1 and Figure 3 As shown, a recessed positioning groove 14 is formed on the side of the cover plate 10 facing away from the receiving cavity. A through hole 13 is provided in the positioning groove 14 and penetrates the bottom wall of the positioning groove 14. The periphery of the short connector 33 is fixed in the positioning groove 14. Thus, the short connector 33 can avoid increasing the height dimension of the top cover assembly 100 in the vertical direction, resulting in a compact structure and reduced space occupation. At the same time, the positioning groove 14 can also play a role in pre-positioning the short connector 33, preventing the short connector 33 from shifting or tilting during welding with the cover plate 10, and improving the assembly efficiency between the short connector 33 and the cover plate 10.

[0081] In some embodiments of the present invention, such as Figure 1 and Figure 2 As shown, the positive electrode module 20 also includes a positive electrode pressure ring 23. The positive electrode pressure ring 23 is arranged on the side of the cover plate 10 away from the receiving cavity. The positive electrode pressure ring 23 is sleeved on the radially outer side of the positive electrode post 21 and is fixedly connected to the positive electrode post 21. In this embodiment, by setting the positive electrode pressure ring 23, the connection contact area between the positive electrode module 20 and the external electrical connector can be increased, improving the stability and reliability of the electrical connection. At the same time, the positive electrode pressure ring 23 can also play a role in positioning and limiting the positive electrode post 21, improving the structural strength and installation stability of the positive electrode post 21.

[0082] In some examples, the positive electrode ring 23 and the conductive sheet 22 are stacked in the thickness direction of the cover plate 10, and the inner circumference of the positive electrode ring 23 is flush with the inner circumference of the conductive sheet 22, while the outer circumference of the conductive sheet 22 extends radially outward beyond the outer circumference of the positive electrode ring 23.

[0083] In some embodiments of the present invention, such as Figure 1 and Figure 3 As shown, the negative electrode module 30 further includes a fixing member 35, which extends circumferentially along the first insulating plate 34. In the longitudinal direction of the cover plate 10, the fixing member 35 is arranged on the side edge of the first insulating plate 34 away from the negative electrode post 31 (e.g., ...). Figure 1 As shown in the diagram, the first insulating plate 34 (left edge) is fixedly connected to the cover plate 10 by a fastener 35. For example, the fastener 35 can extend circumferentially along the first insulating plate 34 in a U-shape facing the right side. This facilitates the fixed installation of the first insulating plate 34, improves the connection reliability between the first insulating plate 34 and the cover plate 10, and enhances the sealing performance between the first insulating plate 34 and the cover plate 10.

[0084] In some embodiments of the present invention, such as Figure 1 and Figure 5 As shown, the top cover assembly 100 further includes a second insulating plate 60. The second insulating plate 60 is disposed on the side of the cover plate 10 facing the receiving cavity, located between the cover plate 10 and the electrode assembly 200 of the battery cell, to separate the cover plate 10 and the electrode assembly 200 of the battery cell. The second insulating plate 60 can insulate between the cover plate 10 and the electrode assembly 200, avoiding the risk of short circuit caused by contact between the electrode assembly 200 and the cover plate 10. At the same time, it can also reduce the contact between the electrolyte and the cover plate 10, reduce the risk of corrosion of the cover plate 10, and improve the service life of the battery cell.

[0085] In some embodiments of the present invention, such as Figure 1 and Figure 5As shown, the top cover assembly 100 also includes a negative electrode connecting piece 50, which is arranged on the side of the second insulating plate 60 away from the cover plate 10, and is connected to the negative electrode post 31. The negative electrode connecting piece 50 is connected between the negative electrode post 31 and the negative electrode tab of the electrode assembly 200 to realize the electrical connection between the negative electrode post 31 and the negative electrode sheet of the electrode assembly 200, thereby ensuring the charge and discharge performance of the battery cell.

[0086] In some examples, the negative electrode connecting piece 50 may have a third fusible link, which can be configured to melt when the negative electrode pressure plate 32 is electrically connected to the cover plate 10 via the shorting member 33. In this embodiment, by providing a third fusible link on the negative electrode connecting piece 50, when a battery cell experiences overcharging or an abnormality and the positive electrode post 21 is short-circuited with the negative electrode post 31, the internal charging circuit of the battery cell is disconnected at the negative electrode connecting piece 50, thus cutting off the internal charging circuit of the battery cell. Of course, in other examples, the negative electrode connecting piece 50 may not have a fusible link; the negative electrode connecting piece 50 may simply serve as an electrical connection between the negative electrode post 31 and the negative electrode tab of the electrode assembly.

[0087] In some embodiments of the present invention, such as Figure 1 and Figure 2 As shown, the positive electrode module 20 further includes a first sealing ring 24, which is sleeved on the positive electrode post 21 and seals against the cover plate 10 and the positive electrode post 21. For example, the first sealing ring 24 can be supported on the upper surface of the first protrusion 211 of the positive electrode post 21 and abut against the lower surface of the cover plate 10. The first sealing ring 24 can seal the gap between the positive electrode post 21 and the first electrode post hole 11, isolating the cavity from the external environment and ensuring the sealing performance of the battery cell.

[0088] In some embodiments of the present invention, such as Figure 1 and Figure 3 As shown, the negative electrode module 30 further includes a second sealing ring 36, which is sleeved on the negative electrode post 31 and seals against the cover plate 10 and the negative electrode post 31. For example, the second sealing ring 36 can be supported on the upper surface of the second protrusion 311 of the negative electrode post 31 and abut against the lower surface of the cover plate 10. The second sealing ring 36 can seal the gap between the negative electrode post 31 and the second post hole 12, isolating the cavity from the external environment and ensuring the sealing performance of the battery cell.

[0089] In some embodiments of the present invention, such as Figure 1 and Figure 5As shown, the top cover assembly 100 also includes an explosion-proof valve 70 and a protective plate 80. The cover plate 10 has a mounting hole 15, the explosion-proof valve 70 is located at the mounting hole 15, and the protective plate 80 covers the side of the explosion-proof valve 70 facing away from the receiving cavity. In this embodiment, by placing the explosion-proof valve 70 at the mounting hole 15 of the cover plate 10, pressure can be quickly released when the internal pressure of the battery cell exceeds the limit, preventing the battery cell from exploding and ensuring the safety of the battery cell. By covering the side of the explosion-proof valve 70 facing away from the receiving cavity with the protective plate 80, the protective plate 80 can prevent external dust, moisture, and impurities from corroding the explosion-proof valve 70 while not obstructing the pressure relief channel, thus improving the reliability and service life of the explosion-proof valve 70.

[0090] A battery cell according to a second aspect embodiment of the present invention includes: a housing, an electrode assembly 200, and a top cover assembly 100 according to the first aspect embodiment of the present invention described above. The housing defines a receiving cavity open on one side; a cover plate 10 is connected to the housing and covers the open side of the receiving cavity, and the electrode assembly 200 is disposed within the receiving cavity. Further, the cover plate 10 may also be provided with an injection hole for injecting electrolyte into the receiving cavity.

[0091] According to the battery cell of the present invention, by providing the top cover assembly 100 of the first aspect embodiment, when the battery cell is overcharged, the positive terminal 21 and the negative terminal 31 can be short-circuited structurally to switch the charging circuit of the battery cell, suppress the overcharging of the battery cell, reduce the risk of thermal runaway or thermal runaway propagation, and improve the overall performance of the battery cell without the need for complex control logic.

[0092] A battery device according to a third aspect embodiment of the present invention includes a battery cell according to the second aspect embodiment described above. For example, the battery device includes a housing and a plurality of battery cells, wherein a battery cavity is defined within the housing, and the plurality of battery cells are stacked and arranged within the housing along the length and width directions of the housing.

[0093] According to the battery device of the present invention, by providing the battery cells of the second aspect embodiment described above, the overall performance of the battery device is improved.

[0094] The following will refer to Figures 1-8 A battery device according to two specific embodiments of the present invention is described.

[0095] In one embodiment, the battery device includes multiple battery cells arranged in a stacked manner. Each battery cell includes a housing, an electrode assembly 200, and a top cover assembly 100. The housing defines a top-open receiving cavity, the electrode assembly 200 is disposed in the receiving cavity, and the top cover assembly 100 covers the top of the receiving cavity.

[0096] Specifically, such as Figure 1As shown, the top cover assembly 100 includes: a cover plate 10, a positive electrode module 20, a negative electrode module 30, a second insulating plate 60, a positive electrode connecting piece 40, a negative electrode connecting piece 50, an explosion-proof valve 70, and a protective plate 80. The cover plate 10 is a rectangular aluminum plate, and the cover plate 10 is provided with first electrode post holes 11, second electrode post holes 12, through holes 13, and mounting holes 15 arranged at intervals along the length direction. The positive electrode connecting piece 40 and the negative electrode connecting piece 50 are both disposed in the receiving cavity, and a second fusible portion 41 is formed on the positive electrode connecting piece 40.

[0097] like Figure 1 and Figure 2 As shown, the positive electrode module 20 is located at the first electrode post hole 11 and includes a positive electrode post 21, a positive electrode pressure ring 23, a conductive sheet 22, and a first sealing ring 24. Both the positive electrode pressure ring 23 and the conductive sheet 22 are annular and sleeved on the positive electrode post 21, located on the upper side of the cover plate 10. The conductive sheet 22 abuts against the positive electrode pressure ring 23 and the cover plate 10. The first sealing ring 24 abuts against the lower surface of the cover plate 10 and the first protruding edge 211 of the positive electrode post 21. The conductive sheet 22 is a current stabilizer with a certain internal resistance.

[0098] like Figure 1 and Figure 3 As shown, the negative electrode module 30 is located at the second electrode post hole 12 and includes: a negative electrode post 31, a negative electrode pressure plate 32, a shorting connector 33, a first insulating plate 34, a fixing member 35, and a second sealing ring 36. The negative electrode post 31 includes a first column and a second column connected in the vertical direction. The first column is connected to the side of the second column facing the receiving cavity. The first column is made of copper, and the second column is made of aluminum. The negative electrode plate 32 includes a pressure ring portion 321, a shorting plate portion 322, and a first fuse portion 323. The pressure ring portion 321 is sleeved on the outside of the negative electrode post 31. The shorting plate portion 322 is arranged on the side of the pressure ring portion 321 facing the positive electrode module 20 along the length direction of the cover plate 10. The shorting plate portion 322 is vertically aligned with the through hole 13. The first fuse portion 323 connects the shorting plate portion 322 and the pressure ring portion 321. The shorting element 33 is a spring piece, which is fixed to the cover plate 10 and seals the through hole 13, and there is a gap between the spring piece and the shorting plate portion 322. A first insulating plate 34 is arranged between the negative electrode plate 32 and the cover plate 10 to separate the cover plate 10 from the negative electrode plate 32. A second sealing ring 36 abuts against the lower surface of the cover plate 10 between the second protruding edge 311 of the negative electrode post 31.

[0099] In the battery device of this embodiment, during the overcharging process of a single battery cell, the air pressure inside the casing of the single battery cell increases, pushing the spring to abut against the shorting plate portion 322 of the negative electrode pressure plate 32, so that the cover plate 10 and the negative electrode pressure plate 32 are shorted through the spring, that is, the positive electrode post 21 and the negative electrode post 31 are shorted, forming a large current, thereby melting the second fuse portion 41 on the positive electrode connecting piece 40 and the first fuse portion 323 on the negative electrode pressure plate 32, thereby cutting off the charging circuit of the single battery cell and the charging circuit of the battery device.

[0100] Example 2, as Figures 5-8 As shown, the structure of this embodiment is roughly the same as that of Embodiment 1, with the same components using the same reference numerals. The only difference is that in Embodiment 1, the conductive sheet 22 is only a current stabilizer and the negative electrode plate 32 is provided with a first fuse part 323, while in this Embodiment 2, the conductive sheet 22 is a diode 22a, and is configured to allow current to flow unidirectionally from the cover plate 10 to the positive electrode post 21, and the current cannot flow from the positive electrode post 21 through the cover plate 10 to the negative electrode post 31. The negative electrode plate 32 only includes a shorting plate part 322 and a pressure ring part 321 that are directly connected, and does not include the first fuse part 323.

[0101] In this embodiment of the battery device, during the overcharging process of a single battery cell, the air pressure inside the casing of the battery cell increases, pushing the spring contact against the shorting plate portion 322 of the negative electrode pressure plate 32. This causes the cover plate 10 and the negative electrode pressure plate 32 to be short-circuited through the spring contact, i.e., the positive electrode post 21 and the negative electrode post 31 are short-circuited, forming a large current. This melts the second fuse portion 41 on the positive electrode connecting piece 40, thereby cutting off the charging circuit of the battery cell. When the current in the charging circuit of the battery device flows from the positive electrode post 21 through the cover plate 10, the spring contact, and the negative electrode pressure plate 32 to the negative electrode post 31, the diode 22a can block the current, thereby cutting off the charging circuit of the battery device.

[0102] According to the battery device of the present invention, the charging circuit of the battery cell can be cut off after the battery cell is overcharged. In the battery module or battery device, the charging circuit of the battery module can also be cut off after the battery cell is overcharged, thereby improving the safety of the battery module.

[0103] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this 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 this invention.

[0104] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0105] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0106] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is 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.

[0107] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A top cover assembly (100) for a battery cell, the battery cell having a receiving cavity, characterized in that, include: Cover plate (10); The positive electrode module (20) includes a positive electrode post (21), which is electrically connected to the cover plate (10); The negative electrode module (30) includes a negative electrode post (31), a negative electrode pressure plate (32), a shorting connector (33), and a first insulating plate (34). The negative electrode pressure plate (32) is connected to the negative electrode post (31) and is located on the side of the cover plate (10) away from the receiving cavity. The first insulating plate (34) is arranged between the negative electrode pressure plate (32) and the cover plate (10). The shorting connector (33) is connected to the cover plate (10). The shorting connector (33) is configured to contact the negative electrode pressure plate (32) when the pressure in the receiving cavity is greater than a preset value, and to electrically connect the negative electrode pressure plate (32) to the cover plate (10) through the shorting connector (33). A blocking structure is provided between the positive terminal (21) and the negative terminal (31). The blocking structure is configured to prevent the current of the positive terminal (21) from flowing through the cover plate (10) to the negative terminal (31) when the negative terminal plate (32) is electrically connected to the cover plate (10) through the shorting member (33).

2. The top cover assembly (100) according to claim 1, characterized in that, The negative electrode plate (32) includes a first fusible part (323), which is configured to be fused when the negative electrode plate (32) is electrically connected to the cover plate (10) through the shorting member (33), and the first fusible part (323) forms the blocking structure.

3. The top cover assembly (100) according to claim 2, characterized in that, The current flow cross-sectional area of ​​the first fuse part (323) is 8 square millimeters to 30 square millimeters.

4. The top cover assembly (100) according to claim 2, characterized in that, The negative electrode plate (32) further includes a pressure ring (321) and a shorting plate (322). The pressure ring (321) is connected to the negative electrode post (31). The shorting plate (322) and the shorting member (33) are directly opposite each other in the thickness direction of the cover plate (10). The shorting plate (322) and the pressure ring (321) are connected through the first fusible part (323).

5. The top cover assembly (100) according to claim 1, characterized in that, The positive electrode module (20) further includes a conductive sheet (22), which is arranged on the side of the cover plate (10) away from the receiving cavity and fixed to the cover plate (10). The cover plate (10) is electrically connected to the positive electrode post (21) through the conductive sheet (22).

6. The top cover assembly (100) according to claim 5, characterized in that, The conductive sheet (22) is a diode (22a) and is configured to allow current to flow unidirectionally from the cover plate (10) toward the positive terminal (21), and the conductive sheet (22) is formed as the blocking structure.

7. The top cover assembly (100) according to claim 5, characterized in that, The conductive sheet (22) is annular and sleeved on the radial outside of the positive electrode post (21), and is fixedly connected to the outer peripheral surface of the positive electrode post (21).

8. The top cover assembly (100) according to any one of claims 1-7, characterized in that, Also includes: A positive electrode connecting piece (40) is connected to the positive electrode post (21) and is disposed on the side of the cover plate (10) facing the receiving cavity. The positive electrode connecting piece (40) has a second fuse part (41) which is configured to be melted when the negative electrode pressure plate (32) is electrically connected to the cover plate (10) through the shorting member (33).

9. The top cover assembly (100) according to claim 8, characterized in that, The current flow cross-sectional area of ​​the second fuse part (41) is 8 square millimeters to 30 square millimeters.

10. The top cover assembly (100) according to claim 8, characterized in that, The negative electrode plate (32) includes a first fusible portion (323), which is configured to be melted when the negative electrode plate (32) is electrically connected to the cover plate (10) via the shorting member (33). The first fusible portion (323) forms the blocking structure. The difference in current flow cross-sectional area between the second fuse part (41) and the first fuse part (323) is 0.5 square millimeters to 1 square millimeter.

11. The top cover assembly (100) according to any one of claims 1-7, characterized in that, The shorting member (33) is an elastic member and is configured to elastically deform when the pressure in the receiving cavity is greater than a preset value, so as to contact the negative electrode plate.

12. The top cover assembly (100) according to claim 11, characterized in that, The preset value is 0.2MPa-0.6MPa, and / or the shorting member (33) and the negative electrode plate (32) are directly opposite each other in the thickness direction of the cover plate (10), and the distance between the shorting member (33) and the negative electrode plate (32) is 0.2mm-1mm.

13. The top cover assembly (100) according to claim 12, characterized in that, The preset value is 0.3MPa-0.4MPa; and / or, in the thickness direction of the cover plate (10), the distance between the shorting member (33) and the negative electrode pressure plate (32) is 0.4mm-0.6mm.

14. The top cover assembly (100) according to claim 11, characterized in that, The short connector (33) includes an elastic body (331) and a protrusion (332). The elastic body (331) is fixed to the cover plate (10). The protrusion (332) is connected to the side of the elastic body (331) facing the cover plate (10). When the pressure on the short connector (33) is greater than a preset value, the elastic body (331) undergoes elastic deformation to push the protrusion (332) to contact the negative electrode pressure plate (32).

15. The top cover assembly (100) according to claim 14, characterized in that, The elastic body (331) is an arc-shaped sheet that protrudes away from the cover plate (10), and the periphery of the elastic body (331) is fixed to the cover plate (10).

16. The top cover assembly (100) according to claim 14, characterized in that, The outer contour of the elastic body (331) is circular, and the outer diameter of the elastic body (331) is 17mm-22mm; and / or, the protrusion (332) is cylindrical, and the diameter of the protrusion (332) is 5mm-10mm.

17. The top cover assembly (100) according to claim 11, characterized in that, The cover plate (10) has a through hole (13) extending through the cover plate (10) along the thickness direction. The short connector (33) is provided on the side of the cover plate (10) away from the receiving cavity and covers the through hole (13).

18. The top cover assembly (100) according to claim 17, characterized in that, A recessed positioning groove (14) is formed on the side surface of the cover plate (10) opposite to the receiving cavity. The through hole (13) is provided in the positioning groove (14) and penetrates the bottom wall of the positioning groove (14). The periphery of the short connector (33) is fixed in the positioning groove (14).

19. The top cover assembly (100) according to claim 1, characterized in that, The top cover assembly (100) further includes a second insulating plate (60), which is disposed on the side of the cover plate (10) facing the receiving cavity to separate the cover plate (10) from the electrode assembly of the battery cell.

20. A single battery cell, characterized in that, include: A housing that defines a receiving cavity open on one side; An electrode assembly (200) is disposed within the receiving cavity; The top cover assembly (100) according to any one of claims 1-19, wherein the cover plate (10) is connected to the housing and covers the open side of the receiving cavity.

21. A battery device, characterized in that, Includes the battery cell according to claim 20.

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