Top cover assembly, battery monomer, battery and electric device

Abstract

The utility model relates to a top cover assembly, a battery monomer, a battery and an electric device. The top cover assembly comprises a top cover plate, a terminal and an upper plastic part, the terminal comprises a pole and a welding piece, the pole is arranged on the top cover plate, and the welding piece is connected with the pole. The welding piece is provided with a first surface close to the top cover plate and a second surface far away from the top cover plate. The second surface is provided with a welding area, and the welding area extends towards the interior of the welding piece from the second surface in the thickness direction of the top cover plate. The upper plastic part is arranged between the terminal and the top cover plate in an insulating mode and provided with a third surface opposite to the first surface, and a heat insulation structure is arranged between the first surface and the third surface. The projection of the heat insulation structure and the projection of the welding area are at least partially overlapped in the thickness direction. According to the technical scheme, the influence of welding heat generated during welding of the welding part and the convergence part on the upper plastic part can be effectively reduced, so that the probability of material variation of the upper plastic part due to heating is reduced, and the reliability of the single battery, the battery and the electric device is improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to top cover assemblies, battery cells, batteries, and electrical devices. Background Technology

[0002] As a new energy source, batteries are playing an increasingly important role in energy storage and power. The top cover is a crucial component of a hard-shell battery cell. As batteries develop towards higher space utilization, the design height of the terminals on the top cover is becoming increasingly smaller. When the terminals are welded to external busbars, the welding heat can easily be transferred to the upper plastic component in contact with the terminals, causing material variations in the upper plastic component and affecting the reliability of the battery cell. Utility Model Content

[0003] Therefore, it is necessary to provide a top cover assembly, a battery cell, a battery, and an electrical device to address the problem that the material variation of the upper plastic part caused by the heat of terminal welding affects the reliability of the battery cell.

[0004] In a first aspect, embodiments of this application provide a top cover assembly, including:

[0005] Top cover plate;

[0006] A terminal includes a terminal post and a weldment, the terminal post being disposed on the top cover plate, and the weldment being connected to the terminal post; the weldment has a first surface disposed near the top cover plate and a second surface disposed away from the top cover plate, the second surface having a welding area extending from the second surface along the thickness direction of the top cover plate toward the interior of the weldment; and

[0007] The upper plastic part is insulated between the terminal and the top cover plate, and has a third surface disposed opposite to the first surface;

[0008] A heat insulation structure is provided between the first surface and the third surface; along the thickness direction, the projection of the heat insulation structure at least partially overlaps with the projection of the welding area.

[0009] In some embodiments, along the thickness direction, the projection of the welded area lies within the projection range of the thermal insulation structure; and / or,

[0010] Along the thickness direction, the projection center of the welded area coincides with the projection center of the thermal insulation structure; and / or,

[0011] Along the thickness direction, the projected shape of the heat insulation structure is consistent with the projected shape of the welding area.

[0012] In some embodiments, at least one of the third surface and the first surface is recessed to form a heat insulation groove that opens toward the other, and the heat insulation structure includes the heat insulation groove; along the thickness direction, the projection of the heat insulation groove and the projection of the welding area at least partially overlap.

[0013] In some embodiments, the heat insulation groove includes an adjacently connected groove bottom and groove wall portions, wherein:

[0014] Along the thickness direction, the projected area S1 of the bottom of the groove and the projected area S2 of the welding area satisfy: S1 ≥ 0.5S2; and / or,

[0015] In any longitudinal section of the heat insulation groove, the longitudinal section passes through the center line of the heat insulation groove that is parallel to the thickness direction, and the included angle α between the center line of the groove wall portion satisfies 90°>α≥0°; when α>0°, the shortest distance from the groove wall portion to the center line is increased in the direction away from the bottom of the groove.

[0016] In some embodiments, the heat insulation groove is filled with heat insulation material.

[0017] In some embodiments, the heat insulation groove includes a first heat insulation groove recessed into the third surface.

[0018] In some embodiments, a reinforcing rib is provided on the bottom of the first heat insulation groove, and the protrusion height of the reinforcing rib is less than the recess depth of the first heat insulation groove.

[0019] And / or, the upper plastic part has a fourth surface opposite to the top cover plate, the minimum distance between the fourth surface and the bottom of the first heat insulation groove in the thickness direction is h, and the dimension of the upper plastic part in the width direction of the top cover plate is w, satisfying: 0.1mm≤h≤5mm, and / or, h≥300N / (P*w).

[0020] Where P is the shear strength of the upper plastic part, and N is the unit Newton.

[0021] In some embodiments, a plurality of the reinforcing ribs are disposed around the center of the first heat insulation groove and arranged sequentially in a direction away from the center of the first heat insulation groove, wherein:

[0022] The closer to the center of the first heat insulation groove, the greater the spacing between adjacent reinforcing ribs;

[0023] And / or, the closer to the center of the first heat insulation groove, the smaller the protrusion height of the reinforcing rib;

[0024] And / or, each of the reinforcing ribs includes multiple reinforcing segments connected at an angle along its enclosure direction, the protrusion height of each reinforcing segment increasing from the center to both sides in the enclosure direction.

[0025] In some embodiments, the upper plastic part includes a first hole that extends through the thickness direction and penetrates the third surface; the welded part includes a second hole that extends through the thickness direction; the first hole and the second hole are coaxially arranged; the pole post passes through the first hole and the second hole in sequence and mates with the second hole.

[0026] The minimum distance L2 between the projection of the welding area and the projection of the first hole, and the minimum distance L3 between the projection of the welding area and the projection of the second hole; the projection of the welding area is located within the projection range of the first heat insulation groove, and the interval L4 between the projection outline of the welding area and the projection outline of the first heat insulation groove 11 satisfies: L2≥1.2mm, and / or, L3≥1mm, and / or, 1mm≤L4≤20mm.

[0027] In some embodiments, a protrusion is provided on the third surface, the protrusion surrounds and forms a limiting groove, and the welded part is limited within the limiting groove; along the thickness direction, the projection of the heat insulation structure is located within the projection range of the limiting groove.

[0028] In some embodiments, the dimension of the thermal insulation structure in the thickness direction is D, satisfying: 0.1mm≤D≤5.1mm, and / or, D>k*(Tt) / q;

[0029] And / or, the minimum dimension L1 of the welded part in the thickness direction satisfies: 1mm≤L1≤5mm;

[0030] Wherein, k and q are the thermal conductivity and heat flux density of the insulation structure, respectively, t is the deterioration temperature of the upper plastic part, and T is the temperature of the area below the welding zone on the first surface when the welded part is welded.

[0031] In some embodiments, the top cover plate has a mounting groove at one end facing the upper plastic part, and the upper plastic part is installed in the mounting groove.

[0032] In some embodiments, the recess depth v1 of the mounting groove satisfies: 0 < v1 ≤ 2.1 mm; and / or,

[0033] The upper plastic part is provided with a first heat insulation groove as the heat insulation structure. The minimum distance between the fourth surface of the upper plastic part facing the top cover plate and the bottom of the first heat insulation groove in the thickness direction is h. The recess depth v1 of the mounting groove satisfies: 0 < v1 ≤ 21h.

[0034] In some embodiments, the pole includes a terminal plate and an extension. The terminal plate is located on the side of the top cover plate opposite to the weldment. The extension passes through the top cover plate and the upper plastic part in sequence and is connected to the weldment. Along the thickness direction, the projection of the terminal plate exceeds the projection range of the extension.

[0035] Secondly, embodiments of this application provide a single battery cell, comprising:

[0036] case;

[0037] Electrode assembly;

[0038] As described in any of the above embodiments, the top cover assembly is connected to the housing and together form a receiving cavity. The electrode assembly is disposed inside the housing, and the upper plastic part and the welded part are located on the side of the top cover plate away from the electrode assembly.

[0039] Thirdly, embodiments of this application provide a battery, comprising:

[0040] Busbar;

[0041] As described in the above embodiments, the busbar is arranged on the side of the welded part away from the upper plastic part and is welded to the welding area.

[0042] In some embodiments, the upper plastic part has a fourth surface opposite to the top cover plate, and the minimum distance between the fourth surface and the bottom of the first heat insulation groove in the thickness direction is h, satisfying: h>U / E;

[0043] Wherein, U is the operating voltage of the battery, and E is the dielectric strength of the upper plastic part.

[0044] Fourthly, embodiments of this application provide an electrical device including the battery described in the above embodiments.

[0045] Compared with the prior art, this application has the following beneficial effects:

[0046] The aforementioned top cover assembly, battery cell, and battery have a heat insulation structure between the first surface of the welded part and the third surface of the upper plastic part. Under the heat insulation effect of the heat insulation structure, the welding heat generated during the welding of the welded part and the busbar can be effectively reduced to reduce the impact on the upper plastic part, thereby reducing the probability of material deformation of the upper plastic part due to heat, which helps to improve the reliability of the battery cell, battery, and electrical device. Attached Figure Description

[0047] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0048] Figure 1 This is a schematic diagram of the top cover assembly in some embodiments.

[0049] Figure 2 for Figure 1 An exploded view of the top cover assembly is shown.

[0050] Figure 3 This is a cross-sectional schematic diagram of the top cover assembly and the busbar assembly in some embodiments.

[0051] Figure 4 This is a schematic diagram of the structure of a welded component in some embodiments.

[0052] Figure 5 This is a cross-sectional schematic diagram of the top cover assembly and the busbar assembly in some embodiments.

[0053] Figure 6 This is a cross-sectional schematic diagram of the top cover assembly and the busbar assembly in some embodiments.

[0054] Figure 7 This is a partial cross-sectional view of the top cover assembly and the busbar assembly in some embodiments.

[0055] Figure 8 This is a schematic diagram illustrating the fit between the upper plastic part, the pole, and the welded part in some embodiments.

[0056] Figure 9 for Figure 7 An enlarged view of point B in the diagram.

[0057] Figure 10 This is a schematic diagram of the structure of the upper plastic part in some embodiments.

[0058] Figure 11 This is a schematic diagram of the structure of the upper plastic part in some embodiments.

[0059] Figure 12 This is a schematic diagram of the structure of the upper plastic part in some embodiments.

[0060] Figure 13 This is a schematic diagram of the structure of the upper plastic part in some embodiments.

[0061] Figure 14 This is a schematic diagram of the structure of the upper plastic part in some embodiments.

[0062] Figure 15This is a schematic diagram of the structure of the upper plastic part in some embodiments.

[0063] Figure 16 This is a schematic diagram of the structure of the upper plastic part in some embodiments.

[0064] Figure 17 This is a schematic diagram of the structure of the upper plastic part in some embodiments.

[0065] Figure 18 This is a schematic diagram of the structure of the upper plastic part in some embodiments.

[0066] Figure 19 This is a cross-sectional view of the upper plastic part in some embodiments.

[0067] Figure 20 This is a cross-sectional schematic diagram of the top cover assembly and the busbar assembly in some embodiments.

[0068] Figure 21 This is a schematic diagram illustrating the fit between the upper plastic part, the pole, and the welded part in some embodiments.

[0069] Figure 22 for Figure 3 Enlarged view of point A in the middle.

[0070] Figure 23 This is an exploded view of a single battery cell in some embodiments.

[0071] The reference numerals in the detailed embodiments are as follows:

[0072] 1000, Battery cell; 100, Top cover assembly; 110, Top cover plate; Z, Thickness direction; X, Length direction; Y, Width direction; 111, Mounting groove; 112, Pressure relief hole; 113, Fluid injection hole; 120, Terminal; 121, Terminal post; 121a, Terminal plate; 121b, Extension; 122, Welded part; 122a, Welding area; P1, First surface; P2, Second surface; 122b, Second hole; 130, Upper plastic part; P3, Third surface; P4, Fourth surface; 131, First hole; 132, Protrusion; d, Limiting groove; G, Heat insulation structure; G1, Heat insulation groove;

[0073] G11, First heat insulation groove; G01, Bottom of groove; G02, Groove wall; G12, Second heat insulation groove; 150, Reinforcing rib; 151, Reinforcing section; 160, Sealing ring; 170, Lower plastic part; 180, Explosion-proof valve; 190, Protective patch; 200, Housing; 300, Electrode assembly; 301, Electrode tab; 2000, Busbar; RC, Molten pool. Detailed Implementation

[0074] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0075] In the description of this application, it should be understood that, where they appear, 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 application 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 application.

[0076] Furthermore, where applicable, 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 at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0077] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," "fixing," etc., shall be interpreted broadly. For example, they may refer to a fixed connection, a detachable connection, or an integral part; they may refer to a mechanical connection or an electrical connection; they may refer to a direct connection or an indirect connection through an intermediate medium; they may refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0078] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0079] It should be noted that, if an element is described as "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is described as "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0080] This application addresses the problem that the material variation of the upper plastic part in contact with the electrode post caused by the heat of terminal welding affects the operational stability of the battery cell, and proposes a top cover assembly, a battery cell, a battery, and an electrical device.

[0081] The battery cell involved in the embodiments of this application can be a secondary battery or a primary battery. The battery cell can be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited to these. The battery cell can be cylindrical, flat, cuboid, or other shapes.

[0082] In addition to the top cover assembly, a battery cell typically includes a housing and electrode assemblies. The housing and top cover assembly together form an internal space for accommodating the battery cell. Specifically, the housing may have a cavity formed within it, with at least one end open. The top cover assembly closes the open end of the housing to seal the cavity, and the electrode assemblies are mounted within the cavity. The housing may be, but is not limited to, a metal housing, such as an aluminum housing or a steel housing.

[0083] Electrode assemblies typically include a positive electrode, a negative electrode, and a separator separating the positive and negative electrodes. An electrolyte can be injected into the battery cell, allowing it to penetrate the electrode assembly and provide ion migration pathways for electrochemical reactions, as well as conductivity. Electrode assemblies can be in the form of wound, stacked, or other types. One or more electrode assemblies can be installed within a single battery cell.

[0084] The aforementioned battery can be a battery pack or a battery module. When the battery is a battery pack, the battery pack specifically includes a battery management system (BMS) and multiple battery cells. Multiple battery cells can be electrically connected in series, parallel, or a combination of series and parallel connections, and communicate with the battery management system, which controls and monitors the operating status of each battery cell. Alternatively, multiple battery cells can first be combined with a module management system to form a battery module, and then these battery modules can be electrically connected in series, parallel, or a combination of series and parallel connections to form a battery pack together with the battery management system.

[0085] The battery provided in this application embodiment can be applied to electrical devices to provide electrical energy. Electrical devices can be, but are not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, etc. Taking a vehicle as an example, the battery can be located at the rear, front, or bottom of the vehicle. The battery can provide electrical energy for the vehicle's drive and also for the vehicle's control system.

[0086] The top cover assembly provided in the embodiments of this application will be described in detail below.

[0087] Please refer to Figure 1 , Figure 2 and Figure 3 The top cover assembly 100 provided in this embodiment includes a top cover plate 110, terminals 120, and an upper plastic component 130. Terminal 120 includes a terminal post 121 and a weldment 122. The terminal post 121 is disposed on the top cover plate 110, and the weldment 122 is connected to the terminal post 121. The weldment 122 has a first surface P1 disposed near the top cover plate 110 and a second surface P2 disposed away from the top cover plate 110. A weldment area 122a is provided on the second surface P2, extending from the second surface P2 along the thickness direction Z of the top cover plate 110 toward the interior of the weldment 122. The upper plastic component 130 is insulatingly disposed between the terminals 120 and the top cover plate 110, and has a third surface P3 disposed opposite to the first surface P1. A heat insulation structure G is disposed between the first surface P1 and the third surface P3. Along the thickness direction Z, the projection of the heat insulation structure G at least partially overlaps with the projection of the weldment area 122a.

[0088] The top cover 110 is typically a thin plate structure and can be, but is not limited to, made of metal or plastic. When the battery cell 1000 is a square cell, the top cover 110 is roughly rectangular in shape (e.g., ...). Figure 1As shown, the top cover plate 110 has a smaller dimension in the width direction Y than its dimension in the length direction X, and its dimension in the thickness direction Z is the smallest. In this embodiment, the mention of the width direction Y indicates that the top cover plate 110 is approximately cuboid in shape. In other embodiments, the top cover plate 110 may also be disc-shaped, in which case it can be applied to a cylindrical battery cell 1000. Of course, the top cover plate 110 may also be in other shapes, designed to adapt to the shape of the battery cell 1000.

[0089] When the top cover assembly 100 is applied to the battery cell 1000, the top cover plate 110 mates with the housing 200 of the battery cell 1000 and closes the opening end of the housing 200. The thickness direction Z of the top cover plate 110 usually corresponds to the height direction of the battery cell 1000.

[0090] The terminal 120 is configured primarily to achieve electrical connection between the electrode assembly 300 and the busbar 2000. Specifically, the terminal 120 includes a terminal post 121 and a solder joint 122. Both the terminal post 121 and the solder joint 122 are conductive and can be, but are not limited to, metals such as aluminum or copper. In some embodiments, the terminal 120 is soldered to the busbar 2000 via the solder joint 122. In other embodiments, the terminal 120 is also soldered to the busbar 2000 via the terminal post 121. The configuration of the solder joint 122 enhances the electrical contact area between the terminal 120 and the busbar 2000 and facilitates the soldering of the terminal 120 to the busbar 2000.

[0091] The electrode post 121 is mounted on the top cover plate 110, with one end extending into the receiving cavity and directly or indirectly connected to the electrode tab 301 of the electrode assembly 300, and the other end extending out of the top cover plate 110 and connected to the welding part 122. Specifically, the top cover plate 110 may have an electrode post hole, through which the electrode post 121 passes. The electrode post hole and the electrode post 121 may be sealed together by a sealing ring 160 (e.g., Figure 3 (As shown), to prevent electrolyte leakage from the electrode hole. Of course, the electrode 121 can also be directly mated to the inner wall of the electrode hole to achieve a sealing effect.

[0092] The weldment 122 and the pole post 121 can be connected by assembly, welding, or other means. The arrangement of the weldment 122 and the pole post 121 can be flexibly designed. In one example, the weldment 122 is arranged around the portion of the pole post 121 that extends beyond the top cover plate 110. In another example, the weldment 122 and the pole post 121 are arranged adjacent to each other along a direction intersecting the thickness direction Z.

[0093] The upper plastic component 130 is made of plastic and has an insulating effect. It is positioned between the terminal 120 and the top cover plate 110 to prevent leakage from the top cover plate 110, thus eliminating the requirement for the top cover plate 110 to be insulated. Specifically, the upper plastic component 130 is located on the outer side of the top cover plate 110 (i.e., the side of the top cover plate 110 facing away from the interior of the battery cell 1000). When the top cover plate 110 has the aforementioned terminal hole, the upper plastic component 130 can extend into the terminal hole and mate with the terminal 121 to insulate and isolate the terminal 121 from the top cover plate 110. The welded component 122 can be located on the side of the upper plastic component 130 facing away from the top cover plate 110.

[0094] In the thickness direction Z of the top cover plate 110, the weldment 122 has a first surface P1 opposite to the upper plastic part 130 and a second surface P2 away from the first surface P1. The upper plastic part 130 has a third surface P3 opposite to the first surface P1 (this surface away from the top cover plate 110). In this embodiment, the terminal 120 is welded to the busbar 2000 at least through the weldment 122. Specifically, a welding area 122a is disposed on the second surface P2 of the weldment 122 away from the top cover plate 110, and the welding area 122a is used for welding to the busbar 2000.

[0095] The welding area 122a extends from the second surface P2 along the thickness direction Z of the top cover plate 110 toward the interior of the weldment 122, indicating that the welding area 122a has a certain depth in the thickness direction Z of the top cover plate 110. Thus, when the weldment 122 and the busbar 2000 are hot-melt welded in the welding area 122a, a molten pool RC with a certain depth in the thickness direction Z is formed at the welding area 122a.

[0096] A thermal insulation structure G is provided between the first surface P1 and the third surface P3. The thermal insulation structure G can be a thermal insulation cavity, or it can be a thermal insulation adhesive, thermal insulation sheet, thermal insulation block, etc., formed of thermal insulation material. Thermal insulation materials include, but are not limited to, aerogel, polyurethane, polystyrene, etc.

[0097] Along the thickness direction Z of the top cover plate 110, the projection of the thermal insulation structure G and the projection of the welding area 122a at least partially overlap, including the projection of the welding area 122a falling within the projection range of the thermal insulation structure G, and also including partial overlap of the two projections. The projection of the welding area 122a may be circular, square or other irregular shape, and the projection of the thermal insulation structure G may be circular, square or other irregular shape.

[0098] In practical applications, the heat insulation structure G is located below the welding area 122a. When the welding area 122a of the welding part 122 is welded to the busbar 2000, the heat insulation structure G can block the welding heat from being conducted to the upper plastic part 130, thereby reducing the impact of the welding heat on the upper plastic part 130.

[0099] The top cover assembly 100 provided in this application embodiment has a heat insulation structure G between the first surface P1 of the welded part 122 and the third surface P3 of the upper plastic part 130. Under the heat insulation effect of the heat insulation structure G, the welding heat generated when the welded part 122 is welded to the busbar 2000 can be effectively reduced to reduce the impact of the welding heat on the upper plastic part 130, thereby reducing the probability of the upper plastic part 130 changing material due to heat, which helps to improve the reliability of the battery cell 1000 with the top cover assembly 100.

[0100] It is worth mentioning that, in some embodiments of this application, the top cover assembly 100, in addition to including the top cover plate 110, the upper plastic part 130, and the pole post 121, refers to... Figure 2 The top cover assembly 100 may further include a lower plastic member 170, which is disposed on the side of the top cover plate 110 opposite to the upper plastic member 130 (i.e., the inner side of the top cover plate 110) for insulating and isolating between the top cover plate 110 and the electrode assembly 300, thereby reducing the risk of leakage current from the top cover plate 110. In some embodiments, refer to... Figure 1 and Figure 2 A pressure relief hole 112 can be provided on the top cover plate 110. The top cover assembly 100 also includes an explosion-proof valve 180 installed in the pressure relief hole 112. When thermal runaway occurs inside the battery cell 1000, the pressure can be relieved by opening the explosion-proof valve 180, reducing the risk of the battery cell 1000 exploding. A protective patch 190 can also be attached to the outside of the explosion-proof valve 180 to reduce the risk of the explosion-proof valve 180 opening due to other physical reasons (such as impact). In addition, refer to Figure 1 and Figure 2 An injection hole 113 can also be provided on the top cover plate 110 to facilitate the injection of electrolyte into the battery cell 1000.

[0101] In some embodiments, along the thickness direction Z, the projection of the welding area 122a is located within the projection range of the thermal insulation structure G.

[0102] It should be noted that when welding the weldment 122 to the busbar 2000, the cross-sectional area of ​​the molten pool RC formed in the welding area 122a is typically arranged to decrease along the thickness direction Z from the second surface P2 toward the interior of the weldment 122, with the maximum cross-sectional area of ​​the molten pool RC on the weldment 122 located at the second surface P2. In other words, the projected profile of the welding area 122a is determined by the portion located on the second surface P2.

[0103] When the projection of the welding area 122a along the thickness direction Z is located within the projection range of the heat insulation structure G along the thickness direction Z, the path of the welding heat generated at various points of the welding area 122a to the upper plastic part 130 is blocked by the heat insulation structure G in the thickness direction Z. The heat insulation effect is relatively obvious, which can effectively reduce the risk of material deformation of the upper plastic part 130 due to heat.

[0104] In some embodiments, along the thickness direction Z, the projection center of the welding area 122a coincides with the projection center of the thermal insulation structure G.

[0105] The projection center of the welding area 122a is the same as the projection center of the molten pool RC on the welded part 122. At the center, the temperature of the molten pool RC is the highest. By designing the projection center of the heat insulation structure G to coincide with the projection center of the welding area 122a, the center of the heat insulation structure G corresponds to the position of the highest temperature of the molten pool RC, which can effectively isolate the heat at the center of the molten pool RC from the upper plastic part 130. The heat insulation effect of the heat insulation structure G is good.

[0106] In some embodiments, the projected shape of the thermal insulation structure G corresponds to the projected shape of the welding area 122a.

[0107] Specifically, when the projected shape of the welding area 122a is circular (not shown), the projected shape of the thermal insulation structure G is also circular. When the projected shape of the welding area 122a is square (e.g., ... Figure 4 As shown in the figure, the projected shape of the thermal insulation structure G is also square.

[0108] When the projected shape of the heat insulation structure G is consistent with the projected shape of the welding area 122a, the shape of the molten pool RC formed by welding the heat insulation structure G and the welding area 122a is basically consistent. In this way, the heat insulation structure G has a good heat insulation effect.

[0109] In one specific embodiment, along the thickness direction Z, the projection of the welding area 122a completely coincides with the projection of the heat insulation structure G. Thus, the projection shapes of the welding area 122a and the heat insulation structure G are identical, and their projection centers coincide, resulting in a better heat insulation effect produced by the heat insulation structure G.

[0110] In some embodiments, refer to Figure 3 , Figure 5 and Figure 6 At least one of the third surface P3 and the first surface P1 is recessed to form a heat insulation groove G1 that opens toward the other. The heat insulation structure G includes the heat insulation groove G1. Along the thickness direction Z, the projection of the heat insulation groove G1 and the projection of the welding area 122a at least partially overlap.

[0111] Specifically, the heat insulation groove G1 can be formed on the third surface P3 (e.g. Figure 3 As shown, a first heat insulation groove G11 is formed on the third surface P3, or it can be formed on the first surface P1 (e.g., Figure 5 As shown, a second heat insulation groove G12 is formed on the first surface P1, and it can also be formed on the first surface P1 and the third surface P3 (as shown). Figure 6As shown, a first heat insulation groove G11 is formed on the third surface P3, and a second heat insulation groove G12 is formed on the first surface P1. The openings of the first heat insulation groove G11 and the second heat insulation groove G12 are arranged opposite to each other.

[0112] The projection of the heat insulation groove G1 along the thickness direction Z at least partially overlaps with the projection of the welding area 122a along the thickness direction Z, that is, the heat insulation groove G1 is at least partially located below the welding area 122a. The interior of the heat insulation groove G1 is hollow, and the air inside is a low thermal conductivity material, which can block the heat conduction from the welding area 122a to the upper plastic part 130 to a certain extent.

[0113] At this point, by machining the heat insulation groove G1 on the first surface P1 and / or the third surface P3 to construct the heat insulation structure G, the structure of the top cover assembly 100 can be simplified, and the machining is simple and the cost is low.

[0114] Understandably, referring to Figure 7 and Figure 8 The heat insulation groove G1 includes an adjacent groove bottom G01 and a groove wall G02.

[0115] Specifically, the tank wall portion G02 intersects with the tank bottom portion G01, and the two are staggered in the thickness direction Z of the top cover plate 110. The tank wall portion G02 is arranged around the edge of the tank bottom portion G01 and extends in the depth direction of the insulation tank G1. The tank bottom portion G01 is usually planar, which is simple to process. Of course, the tank bottom portion G01 can also be curved.

[0116] The shape of the wall portion G02 is consistent with the shape of the insulation groove G1. When the wall portion G02 is circular, the insulation groove G1 is circular; when the wall portion G02 is square, the insulation groove G1 is square. Naturally, the shape of the wall portion G02 follows the edge contour of the bottom G01. Understandably, the opening of the insulation groove G1 is located at the end of the wall portion G02 opposite to the bottom G01.

[0117] Specifically, in the embodiment, along the thickness direction Z, the projected area S1 of the bottom of the groove G01 and the projected area S2 of the welding area 122a satisfy S1≥0.5S2.

[0118] Considering the ease of processing and the heat insulation effect of the heat insulation groove G1, the minimum cross-sectional area of ​​the heat insulation groove G1 is usually located at the bottom G01. In this case, the projected area S1 of the bottom G01 along the thickness direction Z is the projected area of ​​the heat insulation groove G1. The projected area S2 of the welding area 122a is usually equivalent to the area occupied by the welding area 122a on the second surface P2.

[0119] S1 ≥ 0.5S2, meaning S1 / S2 is not less than 0.5. In other words, the projected area of ​​the bottom G01 of the heat insulation groove is not less than half of the projected area S2 of the welding area 122a. In principle, the larger S1 / S2 is, the better the heat insulation effect. Considering that an excessively large heat insulation groove G1 would reduce the mechanical strength of the upper plastic part 130 / welded part 122, the projected area S1 of the bottom G01 of the groove should not be set too large.

[0120] In practical applications, to reduce the impact of welding heat from welded component 122 on the upper plastic component 130, welded component 122 can be made of a metal material with low thermal conductivity (below 200 W / (m*k)), such as iron, stainless steel, titanium alloy, or magnesium alloy. The upper plastic component 130 can be made of a plastic material with a high tempering temperature (above 400℃), such as polyimide or polyetheretherketone. When welded component 122 is made of a material with low thermal conductivity and upper plastic component 130 is made of a material with a high tempering temperature, designing S1 / S2 to be no less than 0.5 can reduce the area occupied by the heat insulation groove G1 while ensuring the heat insulation effect, thus helping to improve the mechanical strength of welded component 122 / upper plastic component 130. In practical applications, S1 / S2 can specifically take values ​​of 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.2, 1.5, etc.

[0121] Of course, other conductive materials with high thermal conductivity, such as copper and aluminum, can be used for the welded part 122. The upper plastic part 130 is made of a material with a low deterioration temperature (below 400℃), such as polyvinyl chloride and polystyrene. In this case, the S1 / S2 ratio can be designed to be no less than 1 to ensure the heat insulation effect.

[0122] It should be noted that the "deterioration temperature" mentioned in the embodiments of this application refers to the temperature at which the material is affected by the welding heat within 60 seconds of welding, which can cause irreversible deterioration of its physical or chemical properties.

[0123] Specifically, in the embodiments, refer to Figure 9 In any longitudinal section of the heat insulation groove G1, the longitudinal section passes through the center line o of the heat insulation groove G1 which is parallel to the thickness direction Z. The included angle α between the groove wall part G02 and the center line o satisfies 90°>α≥0°, and the minimum value of the shortest distance u from the groove wall part G02 to the center line o is located at the end connected to the bottom of the groove G01.

[0124] In practical applications, the centerline o is parallel to the height direction of the battery cell 1000. When the bottom of the tank G01 is a flat part, the centerline o is perpendicular to the bottom of the tank G01. In the longitudinal section, the angle α between the tank wall G02 and the centerline o is in the range of [0°, 90°), which means that the angle α between the tangent of the tank wall G02 at any position on any longitudinal section and the centerline o is in the range of [0°, 90°).

[0125] Specifically, the angles α between the tangents of the tank wall portion G02 at any position on the same longitudinal section and the centerline o can be equal or unequal. If they are equal, the tank wall portion G02 is a straight wall; if they are unequal, the tank wall portion G02 is a non-straight wall.

[0126] If α equals 0°, meaning the angle α between the tangent to the groove wall G02 at any point on the longitudinal section and the center line o is 0°, then the groove wall G02 is a vertically extending wall. When the bottom of the groove G01 is a plane, the groove wall G02 is perpendicular to the bottom of the groove G01, and in any longitudinal section, the shortest distance u from the groove wall G02 to the center line o is the same along the extension direction of the groove wall G02. In this case, the heat insulation groove G1 is a straight groove with a uniform cross-sectional area.

[0127] If α is greater than 0°, since the shortest distance u from the groove wall portion G02 to the center line o increases in the direction away from the groove bottom G01, the groove wall portion G02 is arranged in an outward expansion shape relative to the groove bottom G01. Thus, the closer to the first surface P1 / third surface P3, the larger the cross-sectional area of ​​the heat insulation groove G1, meaning the maximum cross-sectional area of ​​the heat insulation groove G1 is located at its groove opening. This reduces the contact area between the first surface P1 / third surface P3 where the heat insulation groove G1 is located and the opposite surface, thereby reducing the heat transfer area between the welded part 122 and the upper plastic part 130, and reducing the welding heat conducted to the upper plastic part 130.

[0128] Understandably, when α is greater than 0°, if the angle α between the tangent of the groove wall portion G02 at any position on the same longitudinal section and the center line o is equal, then the groove wall portion G02 is an inclined straight wall. If the angle α between the tangent of the groove wall portion G02 at any position on the longitudinal section and the center line o is not equal, then the groove wall portion G02 can be curved, stepped, etc. In a specific example, the groove bottom G01 is a flat portion, and the groove wall portion G02 includes a sloped section and a chamfered section. The sloped section connects the chamfered section and the groove bottom G01, and the angle α between the sloped section and the center line o is smaller than the angle α between the chamfered section and the center line o.

[0129] In contrast, if the angle α between the tangent of the tank wall G02 at any position on the same longitudinal section and the center line o is equal, and the shortest distance u increases away from the bottom of the tank G01, that is, if the tank wall G02 is designed as an inclined straight wall, on the one hand, the tank wall G02 is easy to process, and on the other hand, considering that in order to improve the energy density of the battery cell 1000, the top cover assembly 100 should not be designed to be too thick, and consequently the thickness of the upper plastic part 130 and the welded part 122 should not be designed to be too thick. Thus, the depth of the heat insulation tank G1 is usually designed to be shallow. In this case, designing the tank wall G02 as an inclined straight wall makes the tank wall G02 easier to process and can reduce processing costs.

[0130] In some embodiments, the insulation groove G1 is filled with an insulating material. The insulating material can be an inert gas, aerogel, polyurethane foam, polystyrene foam, etc. Filling with the insulating material can improve the insulation effect of the insulation groove G1.

[0131] In some embodiments, the heat insulation groove G1 includes a first heat insulation groove G11 recessed on the third surface P3. That is, the heat insulation groove G1 is disposed on the upper plastic part 130. In this way, the strength of the welded part 122 can be guaranteed, which is beneficial to the connection strength between the welded part 122 and the busbar 2000, and prevents the welded part 122 from being too thin and thus causing weld breakage.

[0132] Specifically, the shape of the first heat insulation groove G11 can be circular (e.g., Figure 10 and Figure 11 (as shown), square (as shown) Figure 12 As shown), rhombus (as shown) Figure 13 (As shown). The shape of the first heat insulation groove G11 is not specifically limited in the embodiments of this application. However, in some embodiments, the first heat insulation groove G11 is designed as a circular groove, a square groove, or a rhomboid groove for easy processing and manufacturing. It should be noted that the shape of the first heat insulation groove G11 is described in this article based on the projected shape of the first heat insulation groove G11 in the thickness direction Z.

[0133] Specifically, in some embodiments, refer to Figures 14 to 18 The bottom of the first heat insulation groove G11 is provided with a reinforcing rib 150, and the protrusion height m1 of the reinforcing rib 150 is less than the recess depth of the first heat insulation groove G11.

[0134] Based on the above description, the reinforcing rib 150 protrudes from the bottom G01 of the first heat insulation groove G11. Figure 16 Understandably, the protrusion height m1 of the reinforcing rib 150 refers to the distance between the protruding end of the reinforcing rib 150 and its bottom end connected to the bottom of the groove G01 in the thickness direction Z. The recess depth of the first heat insulation groove G11 refers to the distance between the bottom of the first heat insulation groove G11 and the end face of the groove opening end of the first heat insulation groove G11 in the thickness direction Z.

[0135] At this time, a reinforcing rib 150 is provided at the bottom of the first heat insulation groove G11 to enhance the structural strength of the upper plastic part 130. Moreover, the protrusion height of the reinforcing rib 150 is less than the recess depth of the first heat insulation groove G11, and the reinforcing rib 150 will not contact the first surface P1, thus avoiding thermal contact between the reinforcing rib 150 and the welded part 122, reducing the welding heat conducted to the upper plastic part 130, and reducing the risk of material deformation of the reinforcing rib 150 due to heat.

[0136] Based on the features described above, the first heat insulation groove G11 can be filled with heat insulation material. If heat insulation material is filled into the first heat insulation groove G11, the heat insulation material can be dispersed in the remaining space outside the reinforcing rib 150 at the first heat insulation groove G11.

[0137] Further in the embodiments, refer to Figures 15 to 18 Multiple reinforcing ribs 150 are arranged around the center of the first heat insulation groove G11 and sequentially in a direction away from the center of the first heat insulation groove G11.

[0138] That is, each reinforcing rib 150 is arranged around the center of the first heat insulation groove G11. Specifically, each reinforcing rib 150 can be arranged around the center of the first heat insulation groove G11 at angles such as 360°, 180°, 90°, and 45°.

[0139] All reinforcing ribs 150 are arranged sequentially in a direction away from the center of the first heat insulation groove G11, with adjacent reinforcing ribs 150 spaced apart. For example, each reinforcing rib 150 is ring-shaped, and the inner diameter of all reinforcing ribs 150 is not equal, so that they are arranged sequentially in a direction away from the center of the first heat insulation groove G11.

[0140] At this point, the addition of multiple reinforcing ribs 150 can effectively improve the strength of the upper plastic part 130.

[0141] Specifically, in one embodiment, combined with Figure 16 and Figure 19 It is understood that the closer to the center of the first heat insulation groove G11, the larger the spacing m2 between adjacent reinforcing ribs 150.

[0142] The interval m2 between adjacent reinforcing ribs 150 refers to the shortest distance between the outer wall of the inner reinforcing rib 150 and the inner wall of the outer reinforcing rib 150.

[0143] The heat generated during welding in welding zone 122a is higher closer to its center, and the temperature impact on the reinforcing rib 150 is greater closer to the center of the first heat insulation groove G11. Therefore, the closer to the center of the first heat insulation groove G11, the larger the spacing m2 between the reinforcing ribs 150. This indicates that the density of the reinforcing ribs 150 is lower closer to the center of the first heat insulation groove G11, which reduces the number of reinforcing ribs 150 arranged in the central area of ​​the first heat insulation groove G11, thereby reducing the heat insulation space occupied by the reinforcing ribs 150 and improving the heat insulation effect of the first heat insulation groove G11.

[0144] Specifically, in one embodiment, combined with Figures 16 to 19 It is understood that the closer to the center of the first heat insulation groove G11, the smaller the protrusion height m1 of the reinforcing rib 150.

[0145] As mentioned above, the closer to the center of the first heat insulation groove G11, the greater the impact of welding heat. At this time, the smaller the protrusion height m1 of the reinforcing rib 150, which is closer to the center of the first heat insulation groove G11, the less the reinforcing rib 150 is affected by welding heat, and the lower the risk of heat deformation of the reinforcing rib 150.

[0146] Specifically, in one embodiment, refer to Figures 15 to 18 Each reinforcing rib 150 includes multiple reinforcing segments 151 connected at an angle along its enclosure direction, and the protrusion height m1 of each reinforcing segment 151 increases from the center to both sides in the enclosure direction.

[0147] When the reinforcing rib 150 is formed by connecting multiple reinforcing segments 151 at an angle end to end, the reinforcing rib 150 is roughly polygonal in shape, and its enclosing direction is the perimeter direction of the reinforcing rib 150.

[0148] The distance from each reinforcing section 151 to the center of the first heat insulation groove G11 increases from its central position towards both sides, meaning the center of each reinforcing section 151 is closest to the center of the first heat insulation groove G11. At this point, the protrusion height m1 of each reinforcing section 151 exhibits a lower central position and higher side position in the enclosure direction. This reduces the impact of welding heat on the center of the reinforcing rib 150, lowers the risk of thermal deformation of the reinforcing rib 150, and simultaneously increases the filling volume of the heat insulation material within the first heat insulation groove G1, thereby improving the heat insulation effect of the first heat insulation groove G11.

[0149] Of course, the layout of the reinforcing rib 150 is not limited to the above-described scheme. In other embodiments, such as... Figure 14 As shown, multiple reinforcing ribs 150 extend in the same direction as strips, and all reinforcing ribs 150 are arranged side by side at intervals in directions intersecting the extension direction.

[0150] In some embodiments, combined with Figure 20 and Figure 21 It is understood that the upper plastic part 130 has a fourth surface P4 opposite to the top cover plate 110. The minimum distance between the fourth surface P4 and the bottom of the first heat insulation groove G1 in the thickness direction Z is h. The dimension of the upper plastic part 130 in the width direction Y of the top cover plate 110 is w, which satisfies: 0.1mm≤h≤5mm; and / or, h≥300N / (P*w), where P is the shear strength of the upper plastic part 130 and N is a unit Newton.

[0151] The fourth surface P4 is arranged opposite to the third surface P3, and the fourth surface P4 contacts the outer end face of the top cover plate 110. The minimum spacing distance h also represents the thickness of the upper plastic part 130 located below the first heat insulation groove G11. Generally, the location of the minimum spacing distance h reflects the minimum thickness of the upper plastic part 130.

[0152] When h satisfies 0.1mm ≤ h ≤ 5mm, the selectable values ​​for h are 0.1mm, 0.2mm, 0.5mm, 0.8mm, 1mm, 1.2mm, 1.5mm, 1.8mm, 2mm, 0.5mm, 2.8mm, 3mm, 3.5mm, 3.8mm, 4mm, 45mm, 4.8mm, and 5mm. When h takes values ​​within this range, the mechanical strength of the upper plastic part 130 can be guaranteed.

[0153] Shear strength is the ultimate strength of a material when it is sheared, reflecting its ability to resist shear slip. The measurement of the shear strength of the upper plastic part 130 depends on the material type of the upper plastic part 130 and is determined by the corresponding national or industry standard. For example, when the upper plastic part 130 is a non-foamed plastic part, its shear strength can be measured according to the Chinese chemical industry standard HG / T3839-2006 "Plastics Shear Strength Test Method - Perforation Method". As another example, when the upper plastic part 130 is a rigid foamed plastic part, its shear strength can be measured according to the Chinese national standard GB / T10007 "Rigid Foamed Plastics Shear Strength Test Method". Furthermore, when the upper plastic part 130 is a fiber-reinforced plastic, its shear strength can be measured according to the Chinese national standard GB / T1450.1 "Fiber-Reinforced Plastics Interlaminar Shear Strength Test Method".

[0154] The design of h takes into account the material properties of the upper plastic part 130 and its width dimensions. ， When h satisfies h≥300N / (P*w), the upper plastic part 130 can be guaranteed to have sufficient mechanical strength.

[0155] Specifically, optionally, the upper plastic part 130 can be made of a plastic material with a shear strength P within the range of [40 MPa, 200 MPa]. Examples include polyetheretherketone (PEEK), polyimide (PI), and polyphenylene sulfide (PPS). In this case, the upper plastic part 130 possesses high strength, high heat resistance, and high corrosion resistance, which can reduce the risk of shear breakage when the battery cell 1000 with the top cover assembly 100 is subjected to normal shaking.

[0156] Specifically, optionally, the width w of the upper plastic part 130 can be within the range of [10mm, 100mm]. For example, w can be selected as 10mm, 20mm, 30mm, 40mm, 50mm, 60mm, 70mm, 80mm, 90mm, 100mm, and any value between any adjacent selections. When the upper plastic part 130 is designed with a width within the above range, the welded part 122 supporting the upper plastic part 130 can have a larger width, and the welded part 122 can provide a larger welding area 122a, ensuring that the welded part 122 has sufficient welding area.

[0157] In some embodiments, refer to Figure 21 and combined Figure 4 , Figures 14 to 18 Understandably, the upper plastic part 130 includes a first hole 131 that extends through the thickness direction Z and penetrates the third surface P3. The welded part 122 includes a second hole 122b that extends through the thickness direction Z. The first hole 131 and the second hole 122b are coaxially arranged. The pole post 121 passes through the first hole 131 and the second hole 122b in sequence and mates with the second hole 122b.

[0158] At this point, the welded component 122 is arranged around the periphery of the electrode post 121 and makes contact with the electrode post 121 through the second hole 122b, ensuring sufficient conductive area between the two. Specifically, the second hole 122b and the electrode post 121 can be a concave-convex mating joint, ensuring a reliable connection.

[0159] The first hole 131 is located below and coaxial with the second hole 122b. The terminal post 121 passes through the first hole 131 and the second hole 122b sequentially from bottom to top. In this application, "below" refers to the direction along the thickness Z of the top cover plate 110 facing the interior of the battery cell 1000. In one example, the terminal post 121 passes through the first hole 131, with a gap between it and the hole wall to reduce the heat generated when current flows through the terminal post 121 to the upper plastic part 130, and also to improve the insulation effect of the upper plastic part 130 on the terminal post 121 and the top cover plate 110. In other examples, the terminal post 121 is in contact with the hole wall of the first hole 131.

[0160] At this point, the design of the first hole 131 and the second hole 122b helps to ensure the stable installation of the pole post 121.

[0161] Optionally, the weldment 122 is welded to the pole post 121 along the outer edge of the second hole 122b away from the inner side of the top cover plate 110, in which case an annular weld mark f can be formed on the outer edge of the second hole 122b. In practical applications, the weldment 122 can be welded to the pole post 121 before welding the weldment 122 to the busbar 2000, so that the welding of the weldment 122 to the pole post 121 is not restricted by the structure of the busbar 2000.

[0162] In some embodiments, refer to Figure 21 and Figure 20The minimum distance L2 between the projection of welding area 122a and the projection of the first hole 131, and the minimum distance L3 between the projection of welding area 122a and the projection of the second hole 122b. The projection of welding area 122a is located within the projection range of the first heat insulation groove G11, and the interval dimension L4 between the projection outline of welding area 122a and the projection outline of the first heat insulation groove G11 satisfies: L2≥1.2mm, and / or, L3≥1mm, and / or, 1mm≤L4≤20mm.

[0163] In the plane perpendicular to the thickness direction Z, the projection of the welding area 122a is offset from the projection of the first hole 131, and the projection of the welding area 122a is offset from the projection of the second hole 122b. The projection of the welding area 122a is located within the projection range of the first heat insulation groove G11. L2 refers to the minimum distance between the projection of the welding area 122a and the projection of the first hole 131 in this plane, L3 refers to the minimum distance between the projection of the welding area 122a and the projection of the second hole 122b in this plane, and L4 refers to the interval between the projection contour of the welding area 122a and the projection contour of the first heat insulation groove G11 in this plane.

[0164] When L2 ≥ 1.2 mm, the hole wall of the first hole 131 in the upper plastic part 130 is less affected by welding heat, which can effectively reduce the deformation and collapse of the first hole 131 due to welding heat. Specifically, L2 can be selected from values ​​of 1.2 mm, 1.5 mm, 1.8 mm, 2 mm, 5 mm, 10 mm, 20 mm, 30 mm, 50 mm, 80 mm, 100 mm, and any values ​​between any adjacent selections.

[0165] After the welded part 122 and the pole post 121 are welded to form a ring-shaped weld mark, when welding the welded part 122 and the busbar 2000, if the welding area 122a is too close to the first hole 131, the welding heat will have an adverse effect on the weld mark, such as melting the weld mark and causing a false weld.

[0166] When L3 ≥ 1 mm, the welding heat in welding zone 122a has a relatively small thermal impact on the weld bead. Specifically, L3 can be selected from values ​​of 1 mm, 1.5 mm, 1.8 mm, 2 mm, 5 mm, 10 mm, 20 mm, 30 mm, 50 mm, 80 mm, 100 mm, and any values ​​between any adjacent selections.

[0167] Understandably, L2 and L3 are not infinitely large, but are limited by the size of the welded part 122 and the size of the upper plastic part 130. Preferably, 1.2mm≤L2≤20mm and 1≤L3≤20mm.

[0168] When 1mm ≤ L4 ≤ 20mm, it indicates that the projected area of ​​the welding area 122a is smaller than the projected area of ​​the first heat insulation groove G11, and the heat insulation effect of the first heat insulation groove G11 is good. Specifically, L4 can be selected as 1mm, 2, 5mm, 8mm, 10mm, 12mm, 15mm, 18mm, 20mm, or any value between any adjacent selections. Preferably, 1mm ≤ L4 ≤ 10mm, thereby ensuring the mechanical strength of the upper plastic part 130.

[0169] In some embodiments, refer to Figure 5 and Figure 6 A protrusion 132 is provided on the third surface P3, and the protrusion 132 surrounds and forms a limiting groove d. The welded part 122 is limited within the limiting groove d. Along the thickness direction Z, the projection of the heat insulation structure G is located within the projection range of the limiting groove d.

[0170] Specifically, the protrusion 132 can be continuously arranged along the edge of the third surface P3 to form the limiting groove d, or multiple protrusions 132 can be spaced apart along the edge of the third surface P3 and jointly enclosed to form the limiting groove d. The limiting groove d can limit the installation of the welded component 122, improving the positional reliability of the welded component 122 during welding with the busbar 2000, thereby improving the welding quality. The design of the limiting groove d is equivalent to removing part of the structure from the upper plastic part 130 to accommodate the welded component 122, which can reduce the overall size of the top cover assembly 100 in the thickness direction Z, making the top cover assembly 100 more compact.

[0171] Optionally, the end of the protrusion 132 facing away from the top cover plate 110 is lower than the end of the weldment 122 facing away from the top cover plate 110. In this way, when the weldment 122 is welded to the busbar 2000, the busbar 2000 will not be interfered with by the protrusion 132, and the structural design of the busbar 2000 is more flexible.

[0172] In some embodiments, the dimension of the heat insulation structure G in the thickness direction Z is D, which satisfies: 0.1mm≤D≤5.1mm, and / or, D>k*(Tt) / q, where k and q are the thermal conductivity and heat flux density of the heat insulation structure G, respectively, t is the deterioration temperature of the upper plastic part 130, and T is the temperature of the area below the welding area 122a in the first surface P1 when the welded part 122 is welded.

[0173] When the heat insulation structure G is the heat insulation groove G1, D is the depth of the heat insulation groove G1. The larger D is, the better the heat insulation effect of the heat insulation structure G, but too large a value will reduce the thickness of the welded part 122 / upper plastic part 130, which is not conducive to the mechanical strength of both. When D is taken between [0.1mm, 5.1mm], the heat insulation effect and the mechanical strength of the welded part 122 / upper plastic part 130 can be well balanced. Specifically, D can be selected as 0.2mm, 0.5mm, 1mm, 2mm, 3mm, 4mm, 5mm, and any value between any adjacent values.

[0174] Thermal conductivity k, also known as thermal conductivity coefficient, reflects the heat transfer ability of a material. According to Fourier's law, it is defined as the amount of heat transferred per unit time through a unit heat-conducting surface under a unit temperature gradient (a temperature decrease of 1 K over a length of 1 m). When the insulation structure G is an insulation groove G1, its thermal conductivity is determined by the thermal conductivity of the insulation material (such as air, aerogel, etc.) filling the insulation groove G1. The thermal conductivity of the filling material can be obtained by consulting publicly available data or by using thermal conductivity testing equipment; details will not be discussed here.

[0175] Heat flux density q (also known as heat flux) refers to the heat energy passing through a unit area per unit time. Heat flux density t can be measured using conventional methods such as the heat flux meter method and the heat balance method, which will not be discussed here. Please refer to the above text for an explanation of deterioration temperature.

[0176] The temperature T can be determined experimentally. Specifically, the welding process between the weldment 122 and the busbar 2000 is simulated, and the temperature of the area below the welding zone 122a in the first surface P1 is measured using a temperature sensor.

[0177] In this embodiment, D is defined by combining temperature T, thermal conductivity of the insulation structure G, heat flux density and deterioration temperature. The value of D is required to be greater than k*(Tt) / q, so that under the insulation effect generated by the insulation structure G, the welding heat of the welding area 122a has little impact on the performance of the upper plastic part 130.

[0178] In some embodiments, the minimum dimension L1 of the welded part 122 in the thickness direction Z satisfies: 1mm≤L1≤5mm.

[0179] When the second isolation groove G12 is not provided on the first surface P1, L1 refers to the distance between the bottom of the welding area 122a of the welded component 122 and the first surface P1. When the second isolation groove G12 is provided on the first surface P1, L1 refers to the distance between the bottom of the welding area 122a of the welded component 122 and the bottom of the second isolation groove G12. When L1 meets the above range, the welded component 122 has good mechanical strength and will not break during welding due to the welded component 122 being too thin. Specifically, L1 can be selected as 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, and any value between any adjacent selections. Preferably, 1mm ≤ L1 ≤ 2.5mm, thereby reducing the height of the terminal 120 and improving space utilization.

[0180] In some embodiments, refer to Figure 22 The top cover plate 110 has a mounting groove 111 at one end facing the upper plastic part 130, and the upper plastic part 130 is installed in the mounting groove 111. In this case, the mounting groove 111 can accommodate part of the upper plastic part 130, which can reduce the overall size of the top cover assembly 100 in the thickness direction Z and improve the space utilization of the top cover assembly 100. Furthermore, the mounting groove 111 can also position the upper plastic part 130, facilitating its installation.

[0181] In some embodiments, refer to Figure 22 The recess depth v1 of the mounting groove 111 satisfies: 0 < v1 ≤ 2.1 mm. This balances the mechanical strength of the top cover plate 110 with space utilization. Preferably, 0 < v1 ≤ 1.5 mm. Specifically, v1 can be selected from values ​​of 0.1 mm, 0.5 mm, 0.8 mm, 1 mm, 1.2 mm, 1.5 mm, and any values ​​between adjacent selections.

[0182] In some embodiments, the upper plastic part 130 is provided with a first heat insulation groove G11 as a heat insulation structure G. The minimum distance between the fourth surface P4 of the upper plastic part 130 facing the top cover plate 110 and the bottom of the first heat insulation groove G11 in the thickness direction Z is h. The recess depth v1 of the mounting groove 111 satisfies: 0 < v1 ≤ 21h. When an external force impacts the top cover plate 110, the upper plastic part 130 will bear the force from the top cover plate 110. When 0 < v1 ≤ 21h, the mounting groove 111 of the top cover plate 110 can effectively limit and protect the upper plastic part 130, and the upper plastic part 130 can withstand a large force from the top cover plate 110, thus preventing the upper plastic part 130 from cracking.

[0183] In some embodiments, refer to Figure 3 , Figure 5 and Figure 6The terminal post 121 includes a terminal plate 121a and an extension 121b. The terminal plate 121a is located on the side of the top cover plate 110 opposite to the weldment 122. The extension 121b passes through the top cover plate 110 and the upper plastic part 130 in sequence and is connected to the weldment 122. Along the thickness direction Z, the projection of the terminal plate 121a exceeds the projection range of the extension 121b.

[0184] Terminal plate 121a can be electrically connected to electrode 301 directly or indirectly, such as through an adapter piece. Specifically, top cover plate 110 has a pole hole, upper plastic part 130 has a first hole 131, welding part 122 has a second hole 122b, and extension 121b passes through the pole hole, first hole 131, and second hole 122b in sequence. A sealing ring 160 is provided between the pole hole and extension 121b, and extension 121b mates with the second hole 122b. Terminal plate 121a can abut against the end face of pole hole opposite to the second hole 122b.

[0185] At this time, the cross-sectional area of ​​the terminal plate 121a is larger than the cross-sectional area of ​​the extension 121b, so as to achieve a large-area electrical connection with the tab 301 or other adapter structure, thereby increasing the current-passing area of ​​the pole 121.

[0186] In one specific embodiment of this application, a first heat insulation groove G11 is provided on the third surface P3 of the upper plastic part 130. The projection of the welding area 122a of the welded part 122 has the same shape as the projection of the first heat insulation groove G11 and coincides with its center. The projection of the welding area 122a is located within the projection range of the first heat insulation groove G11. The groove wall portion G02 of the first heat insulation groove G11 is arranged in an outwardly expanding shape relative to the groove bottom G01. A reinforcing rib 150 is provided at the bottom of the first heat insulation groove G11. Multiple reinforcing ribs 150 are arranged around the bottom of the first heat insulation groove G11 and are spaced apart in a direction away from the center of the first heat insulation groove G11. The closer to the center of the first heat insulation groove G11, the larger the spacing between adjacent reinforcing ribs 150, and the smaller the protrusion height m1 of each reinforcing member. A first hole 131 and a second hole 122b are respectively provided on the upper plastic part 130 and the welded part 122. The pole post 121 passes through the first hole 131 and the second hole 122b in sequence. The pole post 121 is welded to the weldment 122 to form a ring-shaped weld mark f. A protrusion 132 is provided on the third surface P3 of the upper plastic part 130, forming a limiting groove d, and the weldment 122 is located in the limiting groove d. At the same time, a mounting groove 111 is recessed on the top cover plate 110, and the upper plastic part 130 is located in the mounting groove 111.

[0187] In addition, the battery cell 1000 provided in this application embodiment refers to... Figure 23The system includes a housing 200, an electrode assembly 300, and a top cover assembly 100 as described in any of the above embodiments. The top cover plate 110 is connected to the housing 200 and together they enclose a receiving cavity, in which the electrode assembly 300 is disposed. The upper plastic part 130 and the welded part 122 are located on the side of the top cover plate 110 away from the electrode assembly 300.

[0188] For a description of the housing 200 and the electrode assembly 300, please refer to the above text; it will not be repeated here.

[0189] The battery cell 1000 has the beneficial effects of all the above embodiments.

[0190] In addition, the battery provided in this application embodiment includes a busbar 2000 and a battery cell 1000 as described in the above embodiment. The busbar 2000 is arranged on the side of the welded part 122 away from the upper plastic part 130 and is welded to the welded area 122a.

[0191] The busbar 2000 is typically made of metal, such as aluminum or copper. Optionally, the busbar 2000 covers the terminal 121 and can be in direct contact with or spaced apart from the terminal 121. The same busbar 2000 can be welded to the welding parts 122 of multiple battery cells 1000 to achieve series / parallel connection of multiple battery cells 1000.

[0192] The battery may also include other structures described above, which will not be elaborated here. This battery possesses the beneficial effects of all the embodiments described above.

[0193] In one specific embodiment, the upper plastic part 130 has a fourth surface P4 opposite to the top cover plate 110. The minimum distance h between the fourth surface P4 and the bottom of the first heat insulation groove G11 in the thickness direction Z satisfies: h > U / E. Wherein, U is the operating voltage of the battery, and E is the dielectric strength of the upper plastic part 130.

[0194] The dielectric strength reflects the insulation capability of the upper plastic part 130; the higher the dielectric strength, the stronger the insulation capability. U / E represents the thickness of the upper plastic part 130 that will be broken down when the battery is powered on and the battery's operating voltage is used as the breakdown voltage. h usually represents the minimum thickness of the upper plastic part 130. To avoid the upper plastic part 130 being broken down, h should be greater than U / E.

[0195] Optionally, the upper plastic part 130 is made of a material with a dielectric strength of [15KV / mm, 200KV / mm]. The higher the dielectric strength, the smaller the remaining thickness (i.e., dimension h) of the upper plastic part 130 after slotting. When the maximum thickness of the upper plastic part 130 is constant, the recess depth (i.e., dimension D) of the first heat insulation groove G11 will increase accordingly, that is, there is more space to form the first heat insulation groove G11, and the heat insulation capacity of the first heat insulation groove G11 is higher.

[0196] In addition, this application embodiment also provides an electrical device, including the battery mentioned above, which is used to provide electrical energy. The electrical device can be any of the devices described above, and will not be repeated here. This electrical device has the beneficial effects of all the above embodiments.

[0197] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0198] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A top cover assembly (100), characterized in that, include: Top cover plate (110); A terminal (120) includes a pole (121) and a weldment (122), wherein the pole (121) is disposed on the top cover plate (110), and the weldment (122) is connected to the pole (121); the weldment (122) has a first surface (P1) disposed near the top cover plate (110) and a second surface (P2) disposed away from the top cover plate (110), wherein a welding area (122a) is disposed on the second surface (P2), and the welding area (122a) extends from the second surface (P2) along the thickness direction (Z) of the top cover plate (110) toward the interior of the weldment (122); and The upper plastic part (130) is insulated between the terminal (120) and the top cover plate (110) and has a third surface (P3) disposed opposite to the first surface (P1); A heat insulation structure (G) is provided between the first surface (P1) and the third surface (P3); along the thickness direction (Z), the projection of the heat insulation structure (G) at least partially overlaps with the projection of the welding area (122a).

2. The top cover assembly (100) according to claim 1, characterized in that, Along the thickness direction (Z), the projection of the welded area (122a) lies within the projection range of the thermal insulation structure (G); and / or, Along the thickness direction (Z), the projection center of the welded area (122a) coincides with the projection center of the thermal insulation structure (G); and / or, Along the thickness direction (Z), the projected shape of the thermal insulation structure (G) is consistent with the projected shape of the welding area (122a).

3. The top cover assembly (100) according to claim 1, characterized in that, At least one of the third surface (P3) and the first surface (P1) is recessed to form a heat insulation groove (G1) that opens toward the other, and the heat insulation structure (G) includes the heat insulation groove (G1); along the thickness direction (Z), the projection of the heat insulation groove (G1) and the projection of the welding area (122a) at least partially overlap.

4. The top cover assembly (100) according to claim 3, characterized in that, The heat insulation groove (G1) includes an adjacent groove bottom (G01) and groove wall (G02), wherein: Along the thickness direction (Z), the projected area S1 of the groove bottom (G01) and the projected area S2 of the welding area (122a) satisfy: S1 ≥ 0.5S2; and / or, In any longitudinal section of the heat insulation groove (G1), the longitudinal section passes through the center line (o) of the heat insulation groove (G1) which is parallel to the thickness direction (Z), and the included angle α between the groove wall portion (G02) and the center line (o) satisfies 90°>α≥0°; when α>0°, the shortest distance u from the groove wall portion (G02) to the center line is increased in the direction away from the bottom of the groove (G01).

5. The top cover assembly (100) according to claim 3, characterized in that, The heat insulation groove (G1) is filled with heat insulation material.

6. The top cover assembly (100) according to claim 3, characterized in that, The heat insulation groove (G1) includes a first heat insulation groove (G11) recessed in the third surface (P3).

7. The top cover assembly (100) according to claim 6, characterized in that, The bottom of the first heat insulation groove (G11) is provided with a reinforcing rib (150), and the protrusion height (m1) of the reinforcing rib (150) is less than the recess depth of the first heat insulation groove (G11). And / or, the upper plastic part (130) has a fourth surface (P4) opposite to the top cover plate (110), the minimum distance between the fourth surface (P4) and the bottom of the first heat insulation groove (G11) in the thickness direction (Z) is h, and the dimension of the upper plastic part (130) in the width direction (Y) of the top cover plate (110) is w, satisfying: 0.1mm≤h≤5mm, and / or, h≥300N / (P*w); Wherein, P is the shear strength of the upper plastic part (130), and N is the unit Newton.

8. The top cover assembly (100) according to claim 7, characterized in that, The plurality of reinforcing ribs (150) are arranged around the center of the first heat insulation groove (G11) and sequentially in a direction away from the center of the first heat insulation groove (G11), wherein: The closer to the center of the first heat insulation groove (G11), the larger the spacing (m2) between adjacent reinforcing ribs (150); And / or, the closer to the center of the first heat insulation groove (G11), the smaller the protrusion height (m1) of the reinforcing rib (150); And / or, each of the reinforcing ribs (150) includes multiple reinforcing segments (151) connected at an angle along its enclosure direction, the protrusion height (m1) of each reinforcing segment (151) increasing from the center to both sides in the enclosure direction.

9. The top cover assembly (100) according to claim 6, characterized in that, The upper plastic part (130) includes a first hole (131) that extends through the thickness direction (Z) and penetrates the third surface (P3). The welded part (122) includes a second hole (122b) that extends through the thickness direction (Z). The first hole (131) and the second hole (122b) are coaxially arranged. The pole post (121) passes through the first hole (131) and the second hole (122b) in sequence and mates with the second hole (122b). The minimum distance L2 between the projection of the welding area (122a) and the projection of the first hole (131), and the minimum distance L3 between the projection of the welding area (122a) and the projection of the second hole (122b); the projection of the welding area (122a) is located within the projection range of the first heat insulation groove (G11), and the interval L4 between the projection outline of the welding area (122a) and the projection outline of the first heat insulation groove (G11) satisfies: L2≥1.2mm, and / or, L3≥1mm, and / or, 1mm≤L4≤20mm.

10. The top cover assembly (100) according to any one of claims 1-9, characterized in that, The third surface (P3) is provided with a protrusion (132), which surrounds and forms a limiting groove (C). The welded part (122) is limited to the limiting groove (C). Along the thickness direction (Z), the projection of the heat insulation structure (G) is located within the projection range of the limiting groove (C).

11. The top cover assembly (100) according to any one of claims 1-9, characterized in that, The thermal insulation structure (G) has a dimension D in the thickness direction (Z) that satisfies: 0.1mm ≤ D ≤ 5.1mm, and / or, D > k*(Tt) / q; And / or, the minimum dimension L1 of the welded part (122) in the thickness direction (Z) satisfies: 1mm≤L1≤5mm; Wherein, k and q are the thermal conductivity and heat flux density of the heat insulation structure (G), respectively, t is the deterioration temperature of the upper plastic part (130), and T is the temperature of the area below the welding zone (122a) in the first surface (P1) when the welded part (122) is welded.

12. The top cover assembly (100) according to any one of claims 1-9, characterized in that, The top cover plate (110) has an installation groove (111) at one end facing the upper plastic part (130), and the upper plastic part (130) is installed in the installation groove (111).

13. The top cover assembly (100) according to claim 12, characterized in that, The recess depth v1 of the mounting groove (111) satisfies: 0 < v1 ≤ 2.1 mm; and / or, The upper plastic part (130) is provided with a first heat insulation groove (G11) as the heat insulation structure (G). The minimum distance between the fourth surface (P4) of the upper plastic part (130) facing the top cover plate (110) and the bottom of the first heat insulation groove (G11) in the thickness direction (Z) is h. The recess depth v1 of the mounting groove (111) satisfies: 0<v1≤21h.

14. The top cover assembly (100) according to any one of claims 1-9, characterized in that, The pole post (121) includes a terminal plate (121a) and an extension (121b). The terminal plate (121a) is located on the side of the top cover plate (110) away from the welded part (122). The extension (121b) passes through the top cover plate (110) and the upper plastic part (130) in sequence and is connected to the welded part (122). Along the thickness direction (Z), the projection of the terminal plate (121a) exceeds the projection range of the extension (121b).

15. A single battery cell (1000), characterized in that, include: Casing (200); Electrode assembly (300); The top cover assembly (100) as described in any one of claims 1-14, wherein the top cover plate (110) is connected to the housing (200) and together form a receiving cavity, the electrode assembly (300) is disposed inside the housing (200), and the upper plastic part (130) and the welded part (122) are located on the side of the top cover plate (110) away from the electrode assembly (300).

16. A battery, characterized in that, include: Busbar (2000) ； As claimed in claim 15, the battery cell (1000) is arranged on the side of the welded part (122) away from the upper plastic part (130) and is welded to the welded area (122a).

17. The battery according to claim 16, characterized in that, The upper plastic part (130) has a fourth surface (P4) opposite to the top cover plate (110), and the minimum distance between the fourth surface (P4) and the bottom of the first heat insulation groove (G11) in the thickness direction (Z) is h, which satisfies: h>U / E; Wherein, U is the operating voltage of the battery, and E is the dielectric strength of the upper plastic part (130).

18. An electrical appliance, characterized in that, Includes the battery as described in claim 16 or 17.

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