Battery cells and battery packs

Abstract

This application discloses a battery cell and a battery pack, belonging to the field of batteries. The battery cell includes: a housing with a receiving cavity; an electrode assembly disposed in the receiving cavity, the electrode assembly including a main body and a tab, the tab being electrically connected to the main body; a top cover assembly including a top cover sheet, a lower plastic part, and a terminal post, the top cover sheet being connected to the housing and sealing the receiving cavity, the lower plastic part being connected to the top cover sheet and located on the side of the top cover sheet facing the electrode assembly, and the terminal post passing through the lower plastic part and the top cover sheet; and a connecting piece located between the lower plastic part and the electrode assembly, and electrically connecting the tab and the terminal post, the connecting piece having a heat insulation layer located on the side of the connecting piece facing the lower plastic part. In this application, by providing a heat insulation layer on the connecting piece, the lower plastic part can be effectively protected, thereby improving the safety of the battery cell.

Description

Technical Field

[0001] This application belongs to the field of batteries, specifically relating to a battery cell and a battery pack. Background Technology

[0002] Typically, the electrode assembly is housed within the housing, and the top cover assembly seals the housing, connecting the electrode tabs of the electrode assembly to the terminals of the top cover assembly using connecting tabs. Specifically, the connecting tabs and terminals are welded together using laser welding. However, both the top cover plate and the lower plastic portion of the top cover assembly are penetrated by the terminals. When the connecting tabs are welded to the terminals, the heat from the welding can easily be conducted to the lower plastic portion. The high temperature can cause partial melting of the lower plastic portion, creating plastic burrs. These burrs can easily puncture the diaphragm of the electrode assembly, thus posing a safety hazard. Utility Model Content

[0003] The purpose of this application is to provide a battery cell and battery pack that at least solves the problem that when the connecting piece is welded to the terminal post, the heat of welding is easily conducted to the lower plastic, and the high temperature will cause part of the lower plastic to melt and produce plastic burrs. The plastic burrs can easily puncture the separator of the electrode assembly, thus posing a safety hazard.

[0004] In a first aspect, embodiments of this application provide a single battery cell, comprising:

[0005] case;

[0006] An electrode assembly is disposed within the housing, the electrode assembly comprising a main body and an electrode tab, the electrode tab being electrically connected to the main body;

[0007] A top cover assembly, the top cover assembly including a top cover sheet, a lower plastic and an electrode post, the top cover sheet being connected to the housing, the lower plastic being connected to the top cover sheet and located on the side of the top cover sheet facing the electrode assembly, and the electrode post passing through the lower plastic and the top cover sheet;

[0008] A connecting piece is located between the lower plastic and the electrode assembly, and the connecting piece is electrically connected to the electrode tab and the electrode post. The connecting piece is provided with a heat insulation layer, which is located on the side of the connecting piece facing the lower plastic.

[0009] Optionally, the insulation layer is provided with a window, and the pole is welded to the connecting piece at the location of the window.

[0010] Optionally, the tab is welded to the connecting piece, and the tab is welded to the side of the connecting piece opposite to the lower plastic.

[0011] Optionally, the connecting piece includes a first connecting portion and a second connecting portion connected together, the first connecting portion protruding towards the side of the lower plastic relative to the second connecting portion; the pole post is welded to the first connecting portion, and the electrode tab is electrically connected to the second connecting portion on the side of the connecting piece facing the lower plastic.

[0012] Optionally, the heat insulation layer is disposed on the first connecting portion; or, the heat insulation layer covers the entire connecting piece, and the tab portion is located between the heat insulation layer and the second connecting portion.

[0013] Optionally, the connecting piece is further provided with a protective layer, which is located on the side of the connecting piece opposite to the lower plastic.

[0014] Optionally, an adhesive portion is further provided between the protective layer and the connecting piece; and / or, on a plane perpendicular to the thickness direction of the connecting piece, the protective layer and the projected area of ​​the window have at least partial overlap.

[0015] Optionally, the protective layer is attached to the edge of the insulation layer, and the protective layer can be bent relative to the insulation layer and attached to the connecting piece.

[0016] Optionally, the electrode post has two parts, namely a positive electrode post and a negative electrode post, and at least one of the positive electrode post and the negative electrode post is insulated from the top cover plate; the electrode lug has two parts, namely a positive electrode lug and a negative electrode lug; the connecting piece has two parts, namely a first connecting piece and a second connecting piece;

[0017] The electrode assembly has at least two parts, with the first connecting piece electrically connecting the positive terminal and all the positive electrode tabs, and the second connecting piece electrically connecting the negative terminal and all the negative electrode tabs.

[0018] Secondly, embodiments of this application provide a battery pack including battery cells as described in any of the first aspects above.

[0019] In this embodiment, the tab is electrically connected to the main body, the connecting piece is located between the lower plastic and the electrode assembly, and the connecting piece is electrically connected to the tab and the electrode post. The connecting piece is provided with a heat insulation layer, which is located on the side of the connecting piece facing the lower plastic. Therefore, after the connecting piece is electrically connected to the tab, when welding the connecting piece to the electrode post, the welding heat generated can be blocked by the heat insulation layer, avoiding excessive heat transfer to the lower plastic and preventing the lower plastic from developing plastic burrs. Attached Figure Description

[0020] Figure 1 This represents an exploded view of a single battery cell provided in an embodiment of this application.

[0021] Figure 2 This diagram illustrates a single battery cell provided in an embodiment of this application.

[0022] Figure 3 This is a schematic diagram illustrating a connecting piece provided in this application, wherein a heat insulation layer is provided on the side of the plastic facing downwards.

[0023] Figure 4 This represents one of the isometric views of a connecting piece provided in an embodiment of this application;

[0024] Figure 5 This is a second isometric view of a connecting piece provided in an embodiment of this application;

[0025] Figure 6 This is a schematic diagram showing a protective layer provided in an embodiment of this application, located on the side of the connecting piece away from the lower plastic.

[0026] Figure label:

[0027] 10: Housing; 20: Electrode assembly; 21: Main body; 22: Electrode tab; 22a: Positive electrode tab; 22b: Negative electrode tab; 30: Top cover assembly; 31: Top cover plate; 32: Electrode post; 32a: Positive electrode post; 32b: Negative electrode post; 40: Connecting piece; 40a: First connecting piece; 40b: Second connecting piece; 41: First connecting part; 42: Second connecting part; 50: Heat insulation layer; 501: Window; 60: Protective layer; 61: Adhesive part; 001: Solder mark. Detailed Implementation

[0028] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise stated, "multiple" means two or more. Furthermore, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0029] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are 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, and therefore should not be construed as a limitation of this application.

[0030] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0031] like Figure 1 and Figure 2 As shown, the battery cell includes a housing 10, an electrode assembly 20, a top cover assembly 30, and a connecting piece 40, wherein:

[0032] The housing 10 has a receiving cavity. The housing 10 can be a square battery or a blade battery.

[0033] The electrode assembly 20 is disposed in the receiving cavity. The electrode assembly 20 includes a main body 21 and an electrode tab 22, which is electrically connected to the main body 21.

[0034] The top cover assembly 30 includes a top cover sheet 31, a lower plastic piece, and an electrode post 32. The top cover sheet 31 is connected to the housing 10 and covers the receiving cavity. The lower plastic piece is connected to the top cover sheet 31 and is located on the side of the top cover sheet 31 facing the electrode assembly 20. The electrode post 32 passes through the lower plastic piece and the top cover sheet 31.

[0035] The connecting piece 40 is located between the lower plastic and the electrode assembly 20, and the connecting piece 40 is electrically connected to the electrode tab 22 and the electrode post 32. The connecting piece 40 is provided with a heat insulation layer 50, which is located on the side of the connecting piece 40 facing the lower plastic.

[0036] In this embodiment, the housing 10 has a receiving cavity. A top cover 31 is connected to the housing 10 and seals the receiving cavity. A lower plastic piece is connected to the top cover 31 and located on the side of the top cover 31 facing the electrode assembly 20. An electrode post 32 passes through the lower plastic piece and the top cover 31. The top cover 31 and the housing 10 can protect the devices inside the housing 10. Additionally, the tab 22 is electrically connected to the main body 21. The main body 21 may include stacked and wound positive electrode sheets, negative electrode sheets, and a separator. The tab 22 can be welded to or integrally formed with the positive and negative electrode sheets. A connecting piece 40 is located between the lower plastic piece and the electrode assembly 20, and the connecting piece 40 is electrically connected to the tab 22 and the electrode post 32. The connecting piece 40 has a heat insulation layer 50 located on the side of the connecting piece 40 facing the lower plastic piece. After welding the connecting piece 40 to the tab 22, when welding the connecting piece 40 to the terminal post 32, the welding heat generated during the welding of the connecting piece 40 and the terminal post 32 is blocked by the heat insulation layer 50, preventing excessive heat transfer to the lower plastic and thus avoiding the potential formation of plastic burrs on the lower plastic. In other words, in this embodiment, by providing a heat insulation layer 50 on the connecting piece 40, located on the side of the connecting piece 40 facing the lower plastic, even if the welding heat generated during the welding of the terminal post 32 and the connecting piece 40 is transferred to the connecting piece 40, the welding heat is blocked by the heat insulation layer 50, preventing the welding heat from being transferred to the lower plastic on the top cover 31, which could cause the lower plastic to melt and generate plastic burrs. This prevents the plastic burrs from potentially puncturing the separator in the casing 10 of the single battery cell, thereby posing a risk of damaging the motor assembly in the casing 10 and potentially causing a safety hazard. By setting a heat insulation layer 50 on the connecting piece 40, the lower plastic can be effectively protected, thereby improving the safety of the battery cell.

[0037] It should be noted that when the lower plastic of the top cover plate 31 is heated, i.e., the welding heat is transferred to the lower plastic, the lower plastic may melt and deform. After welding is completed, the deformed lower plastic may form plastic burrs. These plastic burrs may puncture the separator of the electrode assembly 20 in the casing 10 of the single battery cell. In this embodiment, by providing a heat insulation layer 50 on the side of the connecting piece 40 facing the lower plastic of the top cover plate 31, the welding heat is blocked by the heat insulation layer 50 when welding the electrode post 32 to the connecting piece 40, preventing the welding heat from being transferred to the lower plastic of the top cover plate 31 through the connecting piece 40, thereby avoiding the problem of plastic burrs forming on the lower plastic.

[0038] Additionally, in some embodiments, such as Figure 3 As shown, the insulation layer 50 is provided with a window 501, and the pole post 32 is welded to the connecting piece 40 at the position of the window 501.

[0039] Because the insulation layer 50 has an opening 501, the connecting piece 40 at the opening 501 is not covered by the insulation layer 50. In other words, the connecting piece 40 at the opening 501 is not obstructed by the insulation layer 50 and is essentially exposed. Therefore, the connecting piece 40 at the opening 501 can be directly connected to the pole post 32, avoiding the problem of poor welding quality caused by the insulation layer 50 obstructing the connecting piece 40 when connecting the pole post 32 and the connecting piece 40. In short, the opening 501 in the insulation layer 50 allows the pole post 32 to be welded to the connecting piece 40 at the opening 501, facilitating the connection between the pole post 32 and the connecting piece 40.

[0040] It should be noted that when the heat insulation layer 50 is set on the connecting piece 40, the heat insulation layer 50 covers the connecting piece 40, and then an opening 501 is made in the heat insulation layer 50, that is, an opening 501 is made in the complete heat insulation layer 50, so that the connecting piece 40 at the opening 501 position is exposed; of course, when the heat insulation layer 50 is set on the connecting piece 40, the heat insulation layer 50 avoids the set position on the connecting piece 40, and no heat insulation layer 50 is set at the set position, so that the heat insulation layer 50 does not cover the set position, which is equivalent to the heat insulation layer 50 having an opening 501 at the set position.

[0041] like Figure 3 As shown, the area of ​​the window 501 on the connecting piece 40 indicates the location of the solder mark 001. Of course, in actual welding, the solder mark 001 can be a single area or multiple solder marks, which will not be elaborated further.

[0042] Furthermore, in this embodiment, the shape of the window 501 can be set according to actual needs. For example, the shape of the window 501 can be square, or for another example, the shape of the window 501 can be circular. The specific shape of the window 501 is not limited in this embodiment.

[0043] The tab 22 and the connecting piece 40 can be welded in two different positions: one is to weld it to the side of the connecting piece 40 away from the lower plastic, and the other is to weld it to the side of the connecting piece 40 closer to the lower plastic. These will be explained below.

[0044] In some embodiments, the tab 22 is welded to the side of the connecting piece 40 away from the lower plastic. Specifically, the tab 22 is welded to the connecting piece 40, and the tab 22 is welded to the side of the connecting piece 40 away from the lower plastic.

[0045] Since the connecting piece 40 has a heat insulation layer 50 on the side closest to the lower plastic, if the electrode tab 22 is directly welded to the side of the connecting piece with the heat insulation layer 50, the heat insulation layer 50 will block the connection piece 40 and the electrode tab 22, which will easily affect the welding effect. Therefore, the electrode tab 22 can be directly welded to the side of the connecting piece 40 away from the lower plastic, thereby solving this technical problem.

[0046] In some embodiments, the tab 22 is connected to the side of the connecting piece 40 facing downwards towards the plastic. Specifically: as shown in the figure... Figure 4 and Figure 5 As shown, the connecting piece 40 includes a first connecting portion 41 and a second connecting portion 42 connected together. The first connecting portion 41 protrudes towards the side closer to the lower plastic relative to the second connecting portion 42. The pole post 32 is welded to the first connecting portion 41, and the pole tab 22 is electrically connected to the second connecting portion 42 on the side of the connecting piece 40 facing the lower plastic.

[0047] Since the first connecting portion 41 protrudes towards the side closer to the lower plastic relative to the second connecting portion 42, when welding the electrode post 32 to the first connecting portion 41, the protruding first connecting portion 41 serves as a marker, indicating the connection position between the connecting piece 40 and the electrode post 32. Therefore, when welding the electrode post 32 to the connecting piece 40, the first connecting portion 41 can be directly welded to the electrode post 32, facilitating rapid welding. Furthermore, when electrically connecting the electrode tab 22 to the second connecting portion 42, the protruding first connecting portion 41 ensures a gap between the second connecting portion 42 and the top cover plate 31, effectively preventing the electrode tab 22 from contacting the top cover plate 31 and potentially causing leakage.

[0048] It should be noted that in this embodiment of the application, there may be two electrode assemblies 20, and correspondingly, there may be two second connecting portions 42. The first connecting portion 41 is located between the two second connecting portions 42, so that the first connecting portion 41 protrudes relative to the second connecting portion 42, and a step is formed at the connection between the first connecting portion 41 and the second connecting portion 42, that is, two steps are formed on the connecting piece 40. The electrode tabs 22 of the two electrode assemblies 20 are electrically connected to the corresponding second connecting portions 42, such as by welding.

[0049] In some embodiments, the heat insulation layer 50 is disposed on the first connecting portion 41. In other embodiments, the heat insulation layer 50 covers the entire connecting piece 40, and the tab portion 22 is located between the heat insulation layer 50 and the second connecting portion 42.

[0050] When the heat insulation layer 50 is provided on the first connecting part 41, when the first connecting part 41 is welded to the pole post 32, the heat insulation layer 50 on the first connecting part 41 has an opening 501. The first connecting part 41 and the pole post 32 are welded to the position of the opening 501. When the pole post 32 is welded to the first connecting part 41, the heat insulation layer 50 on the first connecting part 41 can effectively block the heat of welding from being transferred to the lower plastic of the top cover plate 31, thus avoiding the problem of plastic burrs being generated due to the melting of the lower plastic.

[0051] When the heat insulation layer 50 covers the entire connecting piece 40, and the electrode tab 22 is located between the heat insulation layer 50 and the second connecting piece 42, it is equivalent to setting the heat insulation layer 50 after welding the electrode tab 22 to the second connecting piece 42. Thus, the heat insulation layer 50 will cover the electrode tab 22, preventing the electrode tab 22 from contacting the top cover piece 31 and causing the top cover piece 31 to have a leakage problem.

[0052] It should be noted that when the heat insulation layer 50 covers the entire connecting piece 40, the heat insulation layer 50 can be a split structure. That is, the heat insulation layer 50 is first set on the first connecting part 41, and the heat insulation layer 50 on the first connecting part 41 has a window 501. When the connecting piece 40 at the window 501 position is welded to the pole post 32, the heat insulation layer 50 on the first connecting part 41 can effectively block the heat transfer to the lower plastic of the top cover piece 31. Then, the pole tab 22 is welded to the side of the second connecting part 42 facing the lower plastic, and after welding, the heat insulation layer 50 is set on the second connecting part 42, so that the heat insulation layer 50 of the first connecting part 41 and the heat insulation layer 50 of the second connecting part 42 are split structures.

[0053] In addition, in this embodiment, when the tab 22 is welded to the side of the connecting piece 40 facing away from the lower plastic, if the heat insulation layer 50 covers the entire connecting piece 40, that is, the side of the connecting piece 40 facing the lower plastic is covered by the heat insulation layer 50, then the heat insulation layer 50 on the side of the connecting piece 40 facing the lower plastic can be an integral structure.

[0054] Additionally, in some embodiments, such as Figure 3 and Figure 6 As shown, the connecting piece 40 also has a protective layer 60, which is located on the side of the connecting piece 40 facing away from the lower plastic. By providing the protective layer 60, the welding position between the electrode post 32 and the connecting piece 40 can be protected. Specifically, after welding the electrode post 32 and the connecting piece 40, the protective layer 60 covers the welding position, preventing welding debris from falling onto the main body 21 of the electrode assembly 20. This prevents debris from piercing the diaphragm of the main body 21 and causing a short circuit between the positive and negative electrodes of the main body 21. In other words, by providing the protective layer 60, the welding position between the connecting piece 40 and the electrode post 32 can be effectively protected.

[0055] Additionally, in some embodiments, such as Figure 3 As shown, an adhesive portion 61 is also provided between the protective layer 60 and the connecting piece 40.

[0056] In some embodiments, the projection areas of the protective layer 60 and the window 501 at least partially overlap on a plane perpendicular to the thickness direction of the connecting piece 40.

[0057] When an adhesive portion 61 is provided between the protective layer 60 and the connecting piece 40, the protective layer 60 can be bonded to the position where the connecting piece 40 and the pole post 32 are welded through the adhesive portion 61. This makes it easier for the protective layer 60 to be attached to the side of the connecting piece 40 away from the lower plastic, and makes the protective layer 60 more secure, avoiding the problem of the protective layer 60 falling off easily.

[0058] The adhesive part 61 can be hot melt adhesive, so that after the connecting piece 40 is welded to the pole 32, the adhesive part 61 is placed at the welding position between the connecting part and the pole 32. The heat of welding can melt the hot melt adhesive to bond the protective layer 60.

[0059] When the projected areas of the protective layer 60 and the window 501 overlap at least partially on a plane perpendicular to the thickness direction of the connecting piece 40, the connecting piece 40 at the window 501 is welded to the electrode post 32. This allows the protective layer 60 to effectively protect the welded area between the electrode post 32 and the connecting piece 40, effectively preventing welding debris from falling onto the main body 21 of the electrode assembly 20. When welding produces debris or other substances, these substances may adhere to the plastic side of the connecting piece 40 facing away from the plastic. The protective layer 60 can cover or seal these debris substances within the connecting piece 40, preventing them from falling or scraping against the main body 21 of the electrode assembly 20. This prevents the diaphragm of the main body 21 from being scraped, leading to insulation failure and a short circuit.

[0060] It should be noted that, in the embodiments of this application, the adhesive portion 61 may be provided only between the protective layer 60 and the connecting piece 40; the projections of the protective layer 60 and the window 501 may at least partially overlap on a plane perpendicular to the thickness direction of the connecting piece 40; the adhesive portion 61 may be provided between the protective layer 60 and the connecting piece 40, and the projections of the protective layer 60 and the window 501 may at least partially overlap on a plane perpendicular to the thickness direction of the connecting piece 40.

[0061] Additionally, in some embodiments, such as Figure 3 and Figure 6 As shown, the protective layer 60 is connected to the edge of the heat insulation layer 50, and the protective layer 60 can be bent relative to the heat insulation layer 50 and attached to the connecting piece 40. With this arrangement, after the electrode post 32 is welded to the connecting piece 40, the protective layer 60 can be bent directly so that the protective layer 60 is attached to the connecting piece 40. Thus, the protective layer 60 protects the welding position of the electrode post 32 and the connecting piece 40, preventing welding debris from falling onto the main body 21 of the electrode assembly 20.

[0062] It should be noted that the protective layer 60 can be a film layer with anti-corrosion function. In this case, after the connecting piece 40 is welded to the electrode post 32, the protective layer 60 is bent so that the protective layer 60 covers the welding position of the electrode post 32 and the connecting piece 40. Thus, the protective layer 60 can not only prevent the welding debris from falling into the main body 21 of the electrode assembly 20, but also prevent the electrolyte inside the single cell from corroding the welding position of the connecting piece 40 and the electrode post 32.

[0063] In addition, in this embodiment, when the protective layer 60 is foldable relative to the heat insulation layer 50, adhesive particles can be pre-coated onto the protective layer 60 to form an adhesive portion 61. After the connecting piece 40 is welded to the pole 32, the protective layer 60 is folded relative to the heat insulation layer 50 to move to the position where the pole 32 and the connecting piece 40 are welded, and the protective layer 60 is attached to the position where the connecting piece 40 and the pole 32 are welded. At this time, the adhesive particles will adhere to the weld mark of the pole 32 and the connecting piece 40. The residual heat of the weld mark can melt the adhesive particles, so that the adhesive particles can bond the protective layer 60 to the connecting piece 40.

[0064] In addition, in some embodiments, the protective layer 60 and the heat insulation layer 50 are made of the same material, and the protective layer 60 and the heat insulation layer 50 are an integral structure.

[0065] With this setup, the same material can be used to process the protective layer 60 and the heat insulation layer 50, which reduces the processing difficulty of the protective layer 60 and the heat insulation layer 50, and also avoids the need to use additional connecting materials to connect the protective layer 60 and the heat insulation layer 50, thus reducing costs.

[0066] In some embodiments, the insulation layer 50 is an aerosol layer, a ceramic layer, or a mica layer. This design makes the insulation layer 50 readily available, thereby reducing its cost.

[0067] In some embodiments, the thickness of the heat insulation layer 50 is L, satisfying the condition: 100um ≤ L ≤ 300um. This setting ensures that the heat insulation layer 50 has good heat insulation performance, and its moderate thickness minimizes its impact on the internal space of the battery cell, thus facilitating the arrangement of other components within the battery cell's casing 10. In other words, by setting the thickness of the heat insulation layer 50 to L, satisfying 100um ≤ L ≤ 300um, the utilization rate of the internal space of the battery cell's casing 10 can be improved while ensuring the heat insulation effect of the heat insulation layer 50.

[0068] Of course, in the embodiments of this application, L can also be less than 100um and greater than 0um, and L can also be greater than 300um. In this respect, the embodiments of this application do not limit it.

[0069] It should be noted that, in the embodiments of this application, the thickness L of the heat insulation layer 50 can be any value from 100um to 300um. For example, L is 100um, L is 150um, L is 200um, L is 250um, and L is 300um.

[0070] In addition, in some embodiments, the thermal conductivity of the insulation layer 50 is less than or equal to 0.026 W / (m·K). This setting allows the insulation layer 50 to have better thermal insulation performance, ensuring that the insulation layer 50 can effectively insulate against heat.

[0071] Additionally, in some embodiments, such as Figure 1 As shown, the electrode post 32 has two parts, namely a positive electrode post 32a and a negative electrode post 32b, at least one of the positive electrode post 32a and the negative electrode post 32b is insulated from the top cover plate 31; the electrode tab 22 has two parts, namely a positive electrode tab 22a and a negative electrode tab 22b; the connecting piece 40 has two parts, namely a first connecting piece 40a and a second connecting piece 40b; the electrode assembly 20 has at least two parts, the first connecting piece 40a is electrically connected to the positive electrode post 32a and all the positive electrode tabs 22a, and the second connecting piece 40b is electrically connected to the negative electrode post 32b and all the negative electrode tabs 22b.

[0072] Typically, the main body 21 of the electrode assembly 20 is electrically connected to the tab 22. After the first connecting piece 40a is electrically connected to the positive terminal 32a and all the positive tabs 22a, and the second connecting piece 40b is electrically connected to the negative terminal 32b and all the negative tabs 22b, it can be ensured that the electrical energy of the cell is transferred to the positive terminal 32a and the negative terminal 32b. Thus, when the single cell is connected to the device to be powered, it is ensured that the electrical energy of the single cell is transferred to the device to be powered. That is, the electrical energy of the single cell forms a circuit through the positive terminal 32a and the negative terminal 32b, ensuring that the single cell can discharge.

[0073] This application provides a battery pack, which includes a battery casing and multiple battery cells as described in any of the above embodiments; the multiple battery cells are installed in the battery casing.

[0074] This application provides an electrical device that includes a battery cell or a battery pack as described in any of the above embodiments.

[0075] It should be noted that, in the embodiments of this application, the electrical equipment may include, but is not limited to, plug-in hybrid vehicles, range-extended hybrid vehicles, and pure electric vehicles.

[0076] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0077] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A battery cell, characterized in that, include: case; An electrode assembly is disposed within the housing, the electrode assembly comprising a main body and an electrode tab, the electrode tab being electrically connected to the main body; A top cover assembly, the top cover assembly including a top cover sheet, a lower plastic and an electrode post, the top cover sheet being connected to the housing, the lower plastic being connected to the top cover sheet and located on the side of the top cover sheet facing the electrode assembly, and the electrode post passing through the lower plastic and the top cover sheet; A connecting piece is located between the lower plastic and the electrode assembly, and the connecting piece is electrically connected to the electrode tab and the electrode post. The connecting piece is provided with a heat insulation layer, which is located on the side of the connecting piece facing the lower plastic.

2. The battery cell according to claim 1, characterized in that, The insulation layer has a window, and the pole is welded to the connecting piece at the position of the window.

3. The battery cell according to claim 2, characterized in that, The electrode tab is welded to the connecting piece, and the electrode tab is welded to the side of the connecting piece opposite to the lower plastic.

4. The battery cell according to claim 2, characterized in that, The connecting piece includes a first connecting portion and a second connecting portion connected together, the first connecting portion protruding towards the side of the lower plastic relative to the second connecting portion; the pole post is welded to the first connecting portion, and the electrode tab is electrically connected to the second connecting portion on the side of the connecting piece facing the lower plastic.

5. The battery cell according to claim 4, characterized in that, The heat insulation layer is disposed on the first connecting portion; or, the heat insulation layer covers the entire connecting piece, and the tab portion is located between the heat insulation layer and the second connecting portion.

6. The battery cell according to any one of claims 2-5, characterized in that, The connecting piece is also provided with a protective layer, which is located on the side of the connecting piece opposite to the lower plastic.

7. The battery cell according to claim 6, characterized in that, An adhesive portion is further provided between the protective layer and the connecting piece; and / or, on a plane perpendicular to the thickness direction of the connecting piece, the protective layer and the projected area of ​​the window have at least partial overlap.

8. The battery cell according to claim 6, characterized in that, The protective layer is attached to the edge of the insulation layer, and the protective layer can be bent relative to the insulation layer and attached to the connecting piece.

9. The battery cell according to claim 1, characterized in that, The electrode post has two parts, namely a positive electrode post and a negative electrode post, and at least one of the positive electrode post and the negative electrode post is insulated from the top cover plate; the electrode lug has two parts, namely a positive electrode lug and a negative electrode lug; the connecting piece has two parts, namely a first connecting piece and a second connecting piece; The electrode assembly has at least two parts, with the first connecting piece electrically connecting the positive terminal and all the positive electrode tabs, and the second connecting piece electrically connecting the negative terminal and all the negative electrode tabs.

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

Images