Battery cell, battery pack, and electric device

Abstract

A battery cell, an electrode terminal is fixed to an end wall and is electrically connected with an electrode assembly, the electrode terminal includes a penetrating part passing through a mounting hole, a first fixing part arranged on the inner side of the end wall in the axial direction, and a second fixing part arranged on the outer side of the end wall in the axial direction; a sealing ring surrounds the penetrating part; the second fixing part clamps at least part of the insulating part between the second fixing part and the end wall, at least part of the sealing ring is extruded between the second fixing part and the end wall, the insulating part surrounds the sealing ring; or at least part of the sealing ring is extruded between the first fixing part and the end wall, the insulating part surrounds the penetrating part, the part of the insulating part clamped between the second fixing part and the end wall includes a groove for detecting whether the sealing ring is missing, and the insulating part further includes a glue inlet arranged in the groove. The utility model aims at providing a battery cell, a battery pack and an electric device, so as to improve the sealing property of the battery cell at least.

Description

Technical Field

[0001] The embodiments of this utility model relate to a battery cell, a battery pack, and an electrical device. Background Technology

[0002] In a single battery cell, an insulating element is placed between the electrode terminals and the end wall of the casing to insulate both the electrode terminals and the end wall. As the performance of battery cells continues to improve, the requirements for their sealing performance are also increasing. Currently, there is room for improvement in the sealing performance between the electrode terminals and the end wall in existing battery cells. Utility Model Content

[0003] In view of the problems existing in the related technologies, the purpose of this utility model is to provide a battery cell, a battery pack and an electrical device, so as to at least improve the sealing performance of the battery cell.

[0004] To achieve the above objectives, this utility model provides a battery cell, comprising: a housing, wherein the housing has an opening at one end in the axial direction and an end wall at the other end opposite to the opening, the end wall having a mounting hole; an electrode assembly disposed within the housing; an electrode terminal fixed to the end wall and electrically connected to the electrode assembly, the electrode terminal including a through portion passing through the mounting hole, a first fixing portion disposed on the inner side of the end wall in the axial direction, and a second fixing portion disposed on the outer side of the end wall in the axial direction; a sealing member surrounding the through portion; and an insulating member, wherein the second fixing portion clamps at least a portion of the insulating member between the second fixing portion and the end wall, at least a portion of the sealing member is pressed between the second fixing portion and the end wall, and the insulating member surrounds the sealing member; or at least a portion of the sealing member is pressed between the first fixing portion and the end wall, the insulating member surrounds the through portion, the portion of the insulating member clamped between the second fixing portion and the end wall includes a groove, the groove being used for gas detection to determine whether the sealing member is missing, and the insulating member further including an adhesive inlet disposed in the groove.

[0005] The beneficial technical effects of this utility model are as follows: For insulating components, factors affecting the sealing performance at the electrode terminals include the sealing performance of the interface between the insulating component and the end wall, and between the electrode terminals. Both the injection port and the groove affect the sealing performance of the interface between the insulating component and the end wall, and between the electrode terminals. In the embodiments of this application, the injection port is set in the groove used to detect whether a leaking seal is installed, and the groove also serves to assist in accurately positioning and matching the injection port with the injection mold head. That is, the injection port, which serves as the injection port, and the groove for leak detection and sealing are combined into one. Therefore, it is not necessary to set the groove for leak detection and sealing in other positions besides the injection port, reducing the impact of the injection port and the groove on the sealing performance of the interface between the insulating component and the end wall, and between the electrode terminals, and improving the sealing reliability of the battery cell at the interface between the insulating component and the electrode terminals and end wall.

[0006] In some embodiments, the number of grooves is n, n≥2, and the n grooves are equidistantly distributed along the circumference of the insulating member, with the glue inlet and the grooves corresponding one-to-one.

[0007] In some embodiments, the n grooves are located on the same surface of the insulating member perpendicular to the axial direction.

[0008] In some embodiments, the n grooves face the outer side of the end wall.

[0009] In some embodiments, along the axial direction, the thickness of the portion of the insulating member disposed between the second fixing portion and the end wall is Z mm, the depth of the groove is M mm, and 15% ≤ M / Z ≤ 30%.

[0010] In some embodiments, the length of the groove along the circumference of the insulating member is H mm, where 0.5 ≤ H ≤ 3.

[0011] In some embodiments, at least one of the grooves in the portion of the insulating member clamped between the second fixing portion and the end wall extends radially through the insulating member, and the glue inlet is located at the center of at least one of the grooves.

[0012] In some embodiments, 0.4≤Z≤1.2, 0.05≤M≤0.2, and along the axial direction, the depth of the inlet is N mm, 0.01≤N≤0.20.

[0013] Embodiments of this application also provide a battery pack, including the aforementioned battery cell.

[0014] Embodiments of this application also provide an electrical device including the aforementioned battery pack. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. It is worth noting that, according to industry standard practice, the components are not drawn to scale and are only used for illustrative purposes. In fact, for clarity of discussion, the dimensions of the components can be arbitrarily increased or decreased.

[0016] Figure 1 A schematic diagram is shown when the electrical device in an embodiment of this application is a vehicle.

[0017] Figure 2 A battery pack according to an embodiment of this application is shown.

[0018] Figure 3 A battery cell and a helium detection device according to an embodiment of this application are shown.

[0019] Figure 4 A cross-sectional view of a battery cell according to an embodiment of this application is shown.

[0020] Figure 5 This is a schematic diagram of the structure of an electrode assembly as an example of this application.

[0021] Figure 6 It shows Figure 4 A magnified view of region E in the middle.

[0022] Figure 7 A bottom view of an insulating member according to an embodiment of this application is shown.

[0023] Figure 8 A perspective view of an insulating member according to an embodiment of this application is shown.

[0024] Figure 9 It shows along Figure 8 A cross-sectional view taken from the BB line.

[0025] Figure 10 It shows Figure 9 A magnified view of region D in the middle.

[0026] Figure 11 It shows Figure 8 A magnified view of region F in the middle.

[0027] Figure 12 A bottom view of an insulating member according to other embodiments of this application is shown.

[0028] Figure 13 A cross-sectional view of a battery cell according to an embodiment of this application is shown.

[0029] Figure 14 It shows Figure 13 A magnified view of region J.

[0030] Figure 15 Half of the cross-sectional view of the insulating element along the axial direction is shown.

[0031] Figure 16 A cross-sectional view of an insulating component and a mold for injection molding an insulating component according to an embodiment of this application is shown.

[0032] Figure 17 It shows Figure 16 The hot nozzle and insulation components.

[0033] Figure 18 The image shows the groove left on the insulation after the hot nozzle is removed, as well as the glue inlet.

[0034] Figure 19 A scheme for applying adhesive to the outer surface of the insulating component is shown. Detailed Implementation

[0035] To better understand the spirit of the embodiments of this application, the following description is based on some preferred embodiments of this application.

[0036] Embodiments of this application will be described in detail below. Throughout this specification, identical or similar components and components having identical or similar functions are indicated by similar reference numerals. The embodiments described herein with reference to the accompanying drawings are illustrative and diagrammatic in nature and are intended to provide a basic understanding of this application. The embodiments of this application should not be construed as limiting this application.

[0037] The terms “approximately,” “generally,” “substantial,” “substantial,” “about,” and “approximately” used herein are used to indicate and explain minor variations. For example, when used in conjunction with numerical values, the above terms may refer to a range of variation less than or equal to ±10% of the corresponding numerical value, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%. As another embodiment, the thickness of a film or layer being “substantially uniform” may refer to the average thickness of the film or layer being less than or equal to ±10% of the standard deviation, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%. The term "substantially coplanar" can refer to two surfaces that are within 50 μm along the same plane (such as within 40 μm, 30 μm, 20 μm, 10 μm, or 1 μm along the same plane). If, for example, two components overlap or overlap within 200 μm, 150 μm, 100 μm, 50 μm, 40 μm, 30 μm, 20 μm, 10 μm, or 1 μm, then the two components can be considered "substantially aligned." If the angle between the two surfaces or components is, for example, 90° ± 10° (such as ± 5°), then the two components are considered "substantially aligned."

[0038] If the angles are ±4°, ±3°, ±2°, ±1°, ±0.5°, ±0.1°, or ±0.05°, then the two surfaces or components can be considered "substantially perpendicular". When used in conjunction with an event or situation, the terms "approximately", "generally", "substantially", "materially", "about", and "approximately" can refer to the exact occurrence of the event or situation as well as the very close approximation of the occurrence.

[0039] In this specification, unless otherwise specified or limited, relative terms such as “central,” “longitudinal,” “lateral,” “front,” “rear,” “right,” “left,” “inner,” “outer,” “lower,” “higher,” “horizontal,” “vertical,” “above,” “below,” “above,” “below,” “top,” “bottom,” and their derivatives (e.g., “horizontally,” “downward,” “upward,” etc.) should be interpreted as referring to the directions described in the discussion or depicted in the accompanying drawings. These relative terms are used for descriptive convenience only and do not require that this application be constructed or operated in a particular orientation.

[0040] For ease of description, "first," "second," "third," etc., can be used in this article to distinguish different components of a figure or a series of figures. "First," "second," "third," etc., are not intended to describe the corresponding components.

[0041] See Figure 1 This application provides an electrical device 1000, which includes a battery pack 300. The working part of the electrical device 1000 is connected to the battery pack 300 to obtain electrical power. As an example, the electrical device 1000 is a vehicle, which can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc., but are not limited thereto. The battery pack 300 is, for example, located at the bottom of the vehicle body 1001 and provides electrical power for the vehicle's operation or the operation of electrical components within the vehicle. However, in other embodiments, the electrical device 1000 can also be a mobile phone, portable device, laptop computer, ship, spacecraft, electric toy, and power tool, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc.; the working part is a unit component capable of obtaining electrical power from the battery pack 300 and performing corresponding work, such as the fan blade rotation unit of a fan, the vacuuming unit of a vacuum cleaner, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric boat toys, and electric airplane toys, etc.; power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This application does not impose any special limitations on the aforementioned electrical device 1000.

[0042] See Figure 2 This application also provides a battery pack 300, which includes individual battery cells 100 and busbars. In one embodiment of the battery pack 300, the battery pack 300 includes a housing 101, a cover 102, and multiple individual battery cells 100. The multiple individual battery cells 100 are placed in the housing 101 and are connected in series or in parallel, or a combination of series and parallel connections. The busbars are connected in series or in parallel to the electrode terminals 40 of the individual battery cells 100. The cover 102 covers the housing 101 to protect the multiple individual battery cells 100. It should be noted that the individual battery cell 100 in this application is a single battery cell. It should also be noted that the battery pack 300 may include, in addition to the individual battery cells 100, a thermal management system, circuit boards, etc. The battery pack 300 may be a battery module, a battery pack, an energy storage cabinet, etc.; these will not be described in detail here.

[0043] Figure 3A battery cell 100 and a gas detection device according to an embodiment of this application are shown, wherein an example is a helium detection device (it is understood that other gases may be used in addition to helium for leak detection). Figure 4 A cross-sectional view of a battery cell 100 according to an embodiment of this application is shown. An embodiment of this application provides a battery cell 100, which includes a housing 10 and a cover plate 30. The housing 10 has an end wall 14 and a side wall 12. At one end of the housing 10 along its axial direction A… Figure 4 The lower end shown is an opening, and the end wall 14 is located at the other end opposite to the opening.

[0044] The sidewall 12 surrounds the end wall 14. As long as a stable seal and electrical connection can be formed, the connection between the end wall 14 and the sidewall 12 can be achieved in various ways, such as integral stamping, integral casting, or separate welding. The circumference of the sidewall 12 is not limited; it can be cylindrical or prismatic, or it can follow any other closed-loop contour that matches the end wall 14. In this embodiment, the outer edge of the end wall 14 is circular, and the sidewall 12 is cylindrical, surrounding the outer edge of the end wall 14, with a circular opening formed at the end of the sidewall 12 facing away from the end wall 14. A cavity is formed within the housing 10 formed by the end wall 14 and the sidewall 12 to accommodate the electrode assembly 120, electrolyte, and other necessary battery components. Specifically, the diameter of the housing 10 can be determined according to the specific size of the electrode assembly 120, such as 18mm, 21mm, or 46mm. The shell 10 can be made of various materials, such as copper, iron, aluminum, steel with nickel layer, aluminum alloy, etc. In order to prevent the shell 10 from rusting during long-term use, a layer of anti-rust material such as metallic nickel can be plated on the surface of the shell 10.

[0045] Figure 5 This is a schematic diagram of the electrode assembly 120 structure of an example of a battery cell 100 of this utility model. The electrode assembly 120 is disposed inside the housing 10 and is a component in the battery cell 100 where an electrochemical reaction occurs. The housing 10 may contain one or more electrode assemblies 120. The electrode assembly 120 includes an electrode sheet and a separator 122, which are wound to form a wound structure. Specifically, in this embodiment, the electrode assembly 120 includes a positive electrode sheet 121, a separator 122, and a negative electrode sheet 123 wound around the housing 10 axially.

[0046] The positive electrode 121 includes a positive current collector 1211 and a positive active material layer coated on the positive current collector 1211. A first coated area 1212 coated with the positive active material layer and a first uncoated area 1213 uncoated with the positive active material layer are formed on the positive current collector 1211. The first coated area 1212 and the first uncoated area 1213 are arranged along the axial direction A of the housing 10. The first uncoated area 1213 extends to the outside of the separator 122 in the height direction of the battery cell 100 and is bent towards the axis of the housing 10 to form a stacked positive electrode tab 125.

[0047] The negative electrode 123 includes a negative current collector 1231 and a negative active material layer coated on the negative current collector 1231. A second coated area 1232 coated with the negative active material layer and a second uncoated area 1233 uncoated with the negative active material layer are formed on the negative current collector 1231. The second coated area 1232 and the second uncoated area 1233 are arranged along the axial direction A of the housing 10. The second uncoated area 1233 extends to the other end of the battery cell 100 in the height direction to the outside of the separator 122 and is bent towards the axis of the housing 10 to form a stacked negative electrode tab 124.

[0048] A separator 122 is disposed between the positive electrode 121 and the negative electrode 123 to isolate the positive and negative active material layers. Taking a lithium-ion battery cell 100 as an example, the positive current collector 1211 can be made of aluminum, and the positive active material layer includes positive active material, which can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative current collector 1231 can be made of copper, and the negative active material layer includes negative active material, which can be carbon or silicon, etc. The substrate material of the separator 122 can be polypropylene (PP) or polyethylene (PE), etc. To protect and insulate the battery cell, an insulating film can also be wrapped around the outside of the battery cell. The insulating film can be synthesized from PP, PE, polyethylene terephthalate (PET), polyvinyl chloride (PVC), or other polymer materials.

[0049] Figure 6 It shows Figure 4The enlarged view of region E shows the electrode assembly 120 and positive current collector 141, which are not shown. The electrode terminal 40 is fixed to the end wall 14 and electrically connected to the electrode assembly 120. The electrode terminal 40 can also be referred to as a terminal post. In this invention, the positive electrode tab 125 faces the end wall 14 or the opening of the housing 10, while the negative electrode tab 124 faces the other end of the housing 10. In this embodiment, the positive electrode tab 125 faces the end wall 14 and is electrically connected to the electrode terminal 40 through the positive current collector 141, making the electrode terminal 40 positively charged. The negative electrode tab 124 faces the opening, and the housing 10 is electrically connected to the negative electrode tab 124 through the negative current collector 142, thus making it negatively charged. However, in another embodiment, the negative electrode tab 124 can be connected to the electrode terminal 40, and the positive electrode tab 125 can be connected to the housing 10.

[0050] The electrode terminal 40 includes a through portion 44 passing through a mounting hole 16 on the end wall 14, and a first fixing portion 41 and a second fixing portion 42 disposed on the inner and outer sides of the end wall 14 in the axial direction A. To prevent electrolyte leakage through the mounting hole 16 to the outside of the battery cell 100, causing a safety accident, or to improve the airtightness of the battery cell 100 under a certain internal pressure, a sealing element 90 is generally provided surrounding the through portion 44 to seal the electrode terminal 40 and the end wall 14. The second fixing portion 42 and the end wall 14 clamp and compress at least part of the sealing element 90. The sealing element 90 can also be called a sealing ring, and it is the component that plays a major sealing role between the electrode terminal 40 and the end wall 14. The material of the sealing element 90 is, for example, fluororubber.

[0051] An insulating member 70 is disposed radially R along the outer side of the seal 90. The insulating member 70 surrounds the seal 90 and is at least partially clamped between the second fixing portion 42 and the end wall 14. The insulating member 70 is disposed outside the housing 10 and may also be referred to as the upper plastic. A lower plastic member 71 is disposed inside the housing 10 and is at least partially clamped between the first fixing portion 41 and the end wall 14. The insulating member 70 and the lower plastic member 71 provide electrical insulation between the electrode terminal 40 and the end wall 14 of the housing 10.

[0052] See Figure 3 After the battery cell 100 is assembled, it is generally necessary to test the sealing performance of the battery cell 100. The commonly used testing method is the helium leak detection method (referred to as the helium test method). The helium leak detection method is a sealing performance testing method that uses helium as the leak indicator gas. During the helium leak detection, the battery cell 100 is first placed in a vacuum-sealed testing chamber, and after the inside of the battery cell 100 is evacuated, helium is injected using a gas cylinder 400. Then, the detection gas probe of the helium detector 402 is set near the electrode terminal 40 to detect the amount of helium leaked from the battery cell 100 into the vacuum-sealed testing chamber, thereby determining the sealing performance of the battery cell 100.

[0053] When testing the sealing performance of battery cells 100, some cells 100 that passed the sealing test still showed leakage after a period of use. Therefore, the accuracy of the sealing performance test results for battery cells 100 is relatively low.

[0054] Research has revealed that when the seal 90 fails (e.g., the seal 90 is missing, making it difficult to detect by observation as it is not located on the surface of the housing 10), the insulating component 70 provides some sealing, which can easily lead to false sealing in the battery cell 100 (i.e., because the seal 90 is not effectively sealing). During sealing tests on the battery cell 100, since the battery cell 100 is not under actual operating conditions, the aforementioned false sealing phenomenon allows the battery cell 100 to meet some sealing test requirements, but not the demands of actual operating conditions. For example, under certain conditions, when the gas pressure increases after internal circulation in the battery cell 100, the absence of the seal 90 prevents it from resisting the gas pressure, causing sealing failure.

[0055] Figure 7 A bottom view of the insulating member 70 according to an embodiment of this application is shown. Figure 8 A perspective view of an insulating member 70 according to an embodiment of this application is shown. Figure 9 It shows along Figure 8 A cross-sectional view taken from the BB line. Figure 10 It shows Figure 9 A magnified view of region D in the middle. Figure 11 It shows Figure 8 A magnified view of region F in the middle.

[0056] To improve the accuracy of the battery cell 100 sealing test results, the portion of the insulating member 70 clamped between the second fixing portion 42 and the end wall 14 includes a groove 78 for gas detection to check for missing seal 90. In embodiments where the first fixing portion 41 is a riveted portion of the electrode terminal 40, i.e., an internal riveting, the groove 78 extends from the outer side 76 of the insulating member 70 facing away from the seal 90 to the inner side 75 facing the seal 90. The groove 78 connects the exterior of the battery cell 100 and the interior of the insulating member 70, so that the exterior of the battery cell 100 is connected to the interior of the housing 10 in the event of seal 90 failure. When testing the sealing performance of the battery cell 100, if the seal 90 fails, the outside of the battery cell 100 and the inside of the casing 10 can be connected through the groove 78. The helium gas filled into the battery cell 100 can flow to the outside of the battery cell 100 through the groove 78. As a result, the amount of helium gas detected by the helium detector 402 will be abnormal, which reduces the interference of false sealing on the test results and improves the accuracy of the sealing performance test results of the battery cell 100.

[0057] The insulating component 70 also includes a sprue 74. During injection molding of the insulating component 70, molten plastic slurry enters the mold through the sprue of the mold for the insulating component 70. Therefore, the sprue 74 is a structure formed on the solidified second insulating component 72 after demolding. The liquid molten plastic slurry flows from the sprue 74 along the circumferential direction C of the insulating component 70 to both sides of the sprue 74 and fills the mold cavity.

[0058] For the insulating component 70, factors affecting the sealing performance at the electrode terminal 40 include the sealing performance of the interface between the insulating component 70 and the end wall 14, and between the electrode terminal 40. Both the glue inlet 74 and the groove 78 affect the sealing performance of the interface between the insulating component 70 and the end wall 14, and between the electrode terminal 40. In the embodiments of this application, the glue inlet 74 is disposed in the groove 78, so it is not necessary to provide the groove 78 at other locations other than the glue inlet 74, thereby reducing the impact of the glue inlet 74 and the groove 78 on the sealing performance of the interface between the insulating component 70 and the end wall 14, and between the electrode terminal 40, and improving the sealing reliability of the battery cell 100 at the interface between the insulating component 70 and the electrode terminal 40, and between the end wall 14.

[0059] The groove 78 is used to fix the injection port 74 in the mold (valve pin 602 and nozzle core 604 of the hot nozzle 600) during injection. Therefore, the groove 78 is used for helium gas detection to check for missing seal 90, and also serves as the injection port. The groove 78 assists in fixing the injection mold head to accurately position and match the injection port 74. In addition, see [reference] Figure 6 When the compression of the seal 90 is large, the groove 78 of the insulator 70 can withstand part of the expansion force from the seal 90, thereby preventing the insulator 70 from lifting due to excessive expansion force from the seal 90.

[0060] Figure 12 A bottom view of the insulating member 70 according to some embodiments of this application is shown. The number of grooves 78 is n, n≥2, with a one-to-one correspondence between the glue inlet 74 and the grooves 78. The n grooves 78 are equidistantly distributed along the circumferential direction C of the insulating member 70 to make the stress on the insulating member 70 more uniform. When n is an even number, the n grooves 78 are symmetrical about the central axis of the insulating member 70 to make the stress on the insulating member 70 symmetrical and improve the reliability of the insulating member 70. In some embodiments, the number of grooves 78 ranges from 1 to 6, preferably 2 to 4. Since the insulating member 70 is annular, the position of the grooves 78 can be randomly selected. In some embodiments, the n grooves 78 are located on the same surface 77 of the insulating member 70 perpendicular to the axial direction A, so as to maximize the thickness m of the portion of the insulating member 70 clamped between the second fixing part 42 and the end wall 14 (see, for example, see...). Figure 9 The distribution is nearly uniform, which improves the reliability of the insulation component 70.

[0061] exist Figures 5 to 12In the embodiment shown, the groove 78 and the glue inlet 74 face the end wall 14, and the CCD camera can identify whether the insulating part 70 is installed backwards, so as to realize the foolproof installation of the insulating part 70. In addition, the groove 78 and the glue inlet 74 are not visible from the outside of the battery cell 100, and the appearance of the battery cell 100 is more complete.

[0062] See Figure 6 The insulating member 70 includes a portion 702 sandwiched between the second fixing portion 42 and the end wall 14, and an outer edge portion 722 surrounding the outer edge of the electrode terminal 40. The outer edge portion 722 limits the second fixing portion 42, which facilitates assembly while ensuring that the second fixing portion 42 can press the insulating member 70, minimizing the offset between the two, making the force on the insulating member 70 more even, avoiding excessive force in some areas that could damage the insulating member 70, improving the sealing performance of the battery cell 100 at the insulating member 70, and preventing the second fixing portion 42 from contacting the end wall 14 beyond the insulating member 70, ensuring that the insulating member 70 provides insulation between the electrode terminal 40 and the end wall 14.

[0063] Figures 4 to 12 The illustration shows an embodiment where the first fixing part 41 is a riveting part of the electrode terminal 40, i.e., an internal riveting connection. Figures 13 to 15 The illustration shows an embodiment where the second fixing part 42 is a riveting part of the electrode terminal 40, i.e., an external riveting connection, wherein... Figure 13 A cross-sectional view along axial direction A of a battery cell 100 according to an embodiment of this application is shown (electrode assembly 120 and current collector are not shown). Figure 14 It shows Figure 13 A magnified view of region J. Figure 15 Half of a cross-sectional view of the insulator 70 along axial direction A is shown. Differences from the internal riveting embodiment include that a portion of the seal 90 is pressed against the first fixing portion 41 and the end wall 14, while the insulator 70 also includes an inner edge 712 extending into the mounting hole 16, the inner edge 712 surrounding the through portion 44; a groove 78 extends radially R from the outer side 76 of the insulator 70 to at least align with the mounting hole 16 (aligned along axial direction A), i.e., the groove 78 penetrates the portion 702 of the insulator 70 held between the second fixing portion 42 and the end wall 14. Other features of the groove 78 and the inlet 74 are the same as or similar to those of the internal riveting embodiment.

[0064] Currently, the injection molding process at Shanghai Plastics is generally a one-out-many method, meaning multiple samples can be produced at once. The current injection molding solutions at Shanghai Plastics involve sprue injection, including cold runner (where there is no heating device in the runner during injection, and the plastic material enters the mold cavity through the cold runner) and hot-to-cold runner (using a hot runner to maintain the fluidity of the molten plastic during injection, gradually transitioning to a cold runner during molding to achieve higher production efficiency and lower material waste). During injection molding, the sprue (the part of the material flowing through the runner during injection, not the product itself) is inevitably present, resulting in significant material waste and a low material utilization rate (product weight / (product + sprue weight)) (e.g., 6.44%). Furthermore, the high cost of plastic raw materials leads to a higher unit price for each product. In addition, during current sprue separation, although the product and sprue automatically separate after cold runner injection, insufficient cooling of the material in the cold runner causes stringing during the separation process. Stringing and whitening are observed at the sprue gate (74), affecting CCD recognition in subsequent processes.

[0065] Figure 16 The diagram shows a cross-sectional view of the insulating component 70 and the mold for injection molding the insulating component 70 according to an embodiment of this application (taking the internal riveting embodiment as an example). The front mold 510, rear mold 512, and mold core 514 form a cavity for accommodating the insulating component 70. The embodiment of this application uses a needle valve type hot runner nozzle 600 for injection. The plastic in the runner is kept in a molten state by the heating tube and nozzle, directly filling the cavity. The runner does not require cooling, and the molded insulating component 70 automatically separates from the runner, generating no waste. This improves the utilization rate of the injection molding material for the insulating component 70, increasing the material utilization rate to 100%. In addition, since a cold runner is not used, stringing at the injection port 74 after demolding is also reduced.

[0066] Figure 17 It shows Figure 16 The hot nozzle 600 and the insulating component 70 are included. Figure 18 The diagram shows the groove 78 left on the insulating part 70 and the inlet 74 after the hot runner 600 is removed. Compared to the sprue injection method (where material flows from the main runner through the branch runner and then into the mold; at the end of injection molding, the material in the branch runner cools to form a sprue, which also needs to be set with a certain chamfer angle for easy separation from the product), the embodiment of this application uses a needle valve type hot runner hot runner 600 for injection. The valve needle 602 of the hot runner 600 opens and closes under the control of a solenoid valve, achieving precise control of the flow of molten plastic: when the valve needle 602 retracts, molten plastic is injected into the cavity; when the valve needle 602 moves forward, it blocks the nozzle core 604 and the inlet 74, stopping the flow of molten plastic. The valve needle 602 and the inlet 74 are precisely matched, leaving a small mark (i.e., the inlet 74) on the surface of the insulating part 70.

[0067] During injection molding, the barrel and hot runner 600 are generally designed on the front mold 510. The only feasible surface for injection of the insulating part 70 is the bottom surface (i.e., the surface 77 of the insulating part 70 facing the end wall 14). (At this time, the insulating part 70 is like...) Figure 16 As shown, it is placed flat, i.e., its radial direction R is on the horizontal plane) and the outer side 76 (at this time, the insulating part 70 is as shown). Figure 19 As shown, it is vertically positioned, meaning its axial direction A is on the horizontal plane. In this embodiment, the insulating component 70 is injected onto the surface 77 facing the end wall 14. After injection molding, the mold core 514 moves downward, which can cause the insulating component 70 to fall, facilitating demolding.

[0068] Figure 19 The diagram shows a method of injecting glue on the outer side 76 of the insulating part 70. When injecting glue on the outer side 76, the placement direction of the insulating part 70 is different from that of the bottom injection method. The mating surface between the insulating part 70 and the mold core 514 does not have a chamfer, which is not conducive to demolding and may cause the insulating part 70 to stick to the front mold 510.

[0069] Furthermore, since the insulating component 70 will exhibit stringing at the injection port 74 after demolding, injecting the adhesive on the outer surface 76 of the insulating component 70 would affect the product's appearance. The embodiments of this application inject the adhesive on the bottom surface of the insulating component 70, which facilitates demolding and improves the product's appearance.

[0070] See Figure 17 and Figure 18 The size of the inlet 74 can be determined based on the size of the valve needle 602 in the hot nozzle 600.

[0071] See Figure 9 In some embodiments, along the axial direction A, the thickness of the portion 702 of the insulating member 70 disposed between the second fixing portion 42 and the end wall 14 is Z mm, where Z ranges from 0.4 to 1.2, preferably from 0.6 to 0.9. See also Figure 10 The depth of groove 78 is M mm, and 15% ≤ M / Z ≤ 30%. See also Figure 17 and Figure 18The depth M of the groove 78 is determined by controlling the distance the nozzle core 604 in the hot nozzle 600 penetrates into the mold cavity. By extending the nozzle core 604 into the mold cavity by M mm, it plays a role in heat conduction, maintaining a stable temperature at the inlet 74, and providing precise guidance for the valve needle 602 to prevent mold misalignment or jamming. In addition, the groove 78 can block the stringing generated on the inlet 74. In some embodiments, the value of M ranges from 0.05 to 0.2, preferably from 0.1 to 0.2. Considering the thickness Z of the portion 702 of the insulating member 70 located between the second fixing part 42 and the end wall 14, if the depth M of the groove 78 is too small, it cannot effectively cover the stringing length generated on the inlet 74, affecting the appearance and assembly of the insulating member 70. If the depth M of the groove 78 is too large, it occupies a large proportion of the thickness Z of the portion 702, which will affect the strength of the insulating member 70 and cause deformation of the insulating member 70 during assembly.

[0072] See Figure 10 The depth of the inlet 74 is N mm, where N ranges from 0.01 to 0.20, preferably from 0.05 to 0.1. (See [reference needed]). Figure 17 and Figure 18 The depth N of the inlet 74 is controlled by the depth of the valve needle 602 inserted into the cavity. The depth of the inlet 74 should not be too large to avoid affecting the strength of the insulating part 70, causing deformation of the insulating part 70, and to avoid affecting the sealing of the interface between the insulating part 70 and the end wall 14 at the inlet 74.

[0073] See also Figure 10 At least one groove 78 has a radial width T equal to the distance from the outer side 76 to the inner side 75 of the insulating member 70, penetrating the insulating member 70 radially R. The distance between the injection port 74 and the outer side 76 is equal to the distance between the injection port 74 and the inner side 75 to prevent the valve needle 602 from shifting from the insulating member 70. Furthermore, the injection port 74 is positioned at the center of the groove 78 to maintain uniform material flow during injection molding and prevent edge material shortages. Figure 15 In the embodiment of external riveting shown, the distance between the glue inlet 74 and the outer side 76 along the radial direction R is equal to the distance between the glue inlet 74 and the mounting hole 16. That is, in the embodiments of external and internal riveting, the distance between the glue inlet 74 and the outer edge of the groove 78 along the radial direction R is equal to the distance between the glue inlet 74 and the inner edge of the groove 78 along the radial direction R.

[0074] See Figure 11Along the circumferential direction C of the insulating component 70, the length of the groove 78 is H mm, where 0.5 ≤ H ≤ 3. H cannot be too large to avoid affecting the number of grooves 78, nor can H be too small, as a short length will cause stress concentration, leading to increased load on the insulating component 70 and deformation. The groove 78 is connected to the surface 77 by an arc transition surface 782 to avoid forming a right-angle edge through a surface perpendicular to the surface 77, which would produce burrs during demolding.

[0075] See Figure 7 and Figure 12 The shape of the projection of the inlet 74 along the axial direction A can be circular, triangular, quadrilateral (e.g., a rectangle such as a square), etc. The shape of the inlet 74 can be designed by designing the shape of the nozzle core 604 and the valve needle 602 of the hot nozzle 600. Regardless of whether the shape of the projection of the inlet 74 along the axial direction A is circular, the maximum radial dimension R and the maximum circumferential dimension C of the inlet 74 are in the range of 0.5-2mm, preferably 0.5-1.5mm. Smaller dimensions can improve the appearance of the insulating part 70, but they cannot be too small, as this will increase injection time and affect efficiency.

[0076] The battery cell 100 in this embodiment is, for example, a cylindrical battery. The casing 10 is made of nickel-coated steel, and the surface of the nickel-coated steel has a nickel coating, which is mainly used to prevent the electrolyte from corroding the nickel-coated steel. Using nickel-coated steel as the casing of a cylindrical battery requires higher sealing performance. If the sealing is poor, water will enter the cylindrical battery and react with the electrolyte to produce hydrogen ions. These hydrogen ions will react with the nickel coating of the nickel-coated steel, corroding the casing 10 and generating nickel ions. These nickel ions will then integrate into / enter the electrode assembly 120, forming nickel metal, which may cause a short circuit between the positive electrode 121 and the negative electrode 123 of the electrode assembly 120, affecting the safety of the cylindrical battery. This embodiment improves the sealing reliability of the battery cell 100 at the insulating member 70 by improving the sealing performance of the interface between the insulating member 70 and the electrode terminal 40 and end wall 14. This prevents water molecules from seeping into the casing 10 from the electrode terminal 40, avoiding the aforementioned technical problems and improving the safety of the battery cell 100.

[0077] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A battery cell, characterized in that, include: A housing having an opening at one axial end and an end wall at the opposite end, the end wall having a mounting hole; Electrode assembly, disposed within the housing; An electrode terminal is fixed to the end wall and electrically connected to the electrode assembly. The electrode terminal includes a through portion passing through the mounting hole, a first fixing portion disposed on the inner side of the end wall in the axial direction, and a second fixing portion disposed on the outer side of the end wall in the axial direction. A sealing element surrounds the through portion; An insulating member, wherein the second fixing portion clamps at least a portion of the insulating member between the second fixing portion and the end wall. At least a portion of the seal is pressed between the second fixing portion and the end wall, and the insulating member surrounds the seal; or at least a portion of the seal is pressed between the first fixing portion and the end wall, and the insulating member surrounds the through portion. The portion of the insulating component held between the second fixing part and the end wall includes a groove, which serves as a gas passage for gas detection when the sealing component is missing. The insulating component also includes an adhesive inlet disposed in the groove.

2. The battery cell according to claim 1, characterized in that, The number of grooves is n, n≥2, and the n grooves are equidistantly distributed along the circumference of the insulating component. The glue inlet and the grooves correspond one-to-one.

3. The battery cell according to claim 2, characterized in that, The n grooves are located on the same surface of the insulating element, perpendicular to the axial direction.

4. The battery cell according to claim 3, characterized in that, The n grooves face the outer side of the end wall.

5. The battery cell according to claim 1, characterized in that, Along the axial direction, the thickness of the portion of the insulating member disposed between the second fixing part and the end wall is Z mm, the depth of the groove is M mm, and 15% ≤ M / Z ≤ 30%.

6. The battery cell according to claim 1, characterized in that, Along the circumference of the insulating element, the length of the groove is H mm, where 0.5 ≤ H ≤ 3.

7. The battery cell according to claim 1, characterized in that, At least one of the grooves in the portion of the insulating member held between the second fixing part and the end wall extends radially through the insulating member, and the glue inlet is located at the center of at least one of the grooves.

8. The battery cell according to claim 5, characterized in that, 0.4≤Z≤1.2, 0.05≤M≤0.2, along the axial direction, the depth of the inlet is N mm, 0.01≤N≤0.

20.

9. A battery pack, characterized in that, Includes the battery cell as described in any one of claims 1 to 8.

10. An electrical device, characterized in that, Includes the battery pack as described in claim 9.

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