Electrode assembly, battery cell and battery pack

Abstract

The utility model relates to the technical field of battery structures, and discloses an electrode assembly, a battery monomer and a battery pack, the electrode assembly comprises an electrode main body and a protection piece, and two end surfaces on the electrode main body along the height direction are electrode end surfaces; the protection piece comprises an end covering part, the end covering part is arranged on the end surface of the electrode provided with the tab, and the end covering part can cover a part of the end surface of the electrode; according to the electrode assembly, the battery monomer and the battery pack disclosed by the utility model, the probability that the performance of the electrode assembly is influenced by metal foreign matters generated by laser welding can be reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of battery structure, in particular to an electrode assembly, a battery cell and a battery pack. Background Art

[0002] With the rapid development of the electric vehicle and energy storage markets, lithium-ion batteries are being used in more and more applications. Compared with other batteries, they have great advantages in size and capacity. Power cells are the core components of lithium batteries, and their yield and safety performance have also received widespread attention.

[0003] In the related art, during the assembly process of lithium-ion batteries, the tabs need to be ultrasonically welded together and then laser welded to the adapter. However, ultrasonic welding of the tabs will produce scattered metal foreign matter, the size of which ranges from tens to hundreds of microns, forming particle or line shapes. The scattered metal foreign matter will enter the interior of the winding core and form micro short-circuit points along with the flow of free electrolyte, which will seriously affect the performance of the electrode assembly. Utility Model Content

[0004] In view of this, the utility model provides an electrode assembly, a battery cell and a battery pack to reduce the probability of metal foreign matter generated by laser welding affecting the performance of the electrode assembly.

[0005] On the one hand, the utility model provides an electrode assembly, including an electrode body and a protective member, wherein the two end faces of the electrode body along its height direction are electrode end faces; the protective member includes an end covering portion, and the end covering portion is provided on the electrode end face provided with a pole ear, and the end covering portion can cover a portion of the electrode end face.

[0006] Beneficial effect: The end covering portion of the protective component is used to partially cover the end surface of the electrode provided with the pole ear. When the electrode body is laser welded for the pole ear, it can block the scattered metal foreign matter during laser welding, reduce the probability of metal foreign matter entering the interior of the electrode body, and thus reduce the probability of metal foreign matter affecting the performance of the electrode assembly. The end covering portion only partially covers the end surface of the electrode and will not affect the replenishment of the external electrolyte to the electrode body.

[0007] In an optional embodiment, the end cover portion is annular.

[0008] Beneficial effects: The end covering portion is annular in shape, simple in shape, and can occupy a larger area of ​​the electrode end surface, which can improve the blocking effect on metal foreign matter and further reduce the probability of metal foreign matter affecting the performance of the electrode assembly.

[0009] In an optional embodiment, the end covering portion includes an annular surface and a cylindrical surface, the outer edge of the annular surface is connected to the edge of one end of the cylindrical surface, the annular surface is in contact with the electrode end surface, and the cylindrical surface is in contact with the electrode annular surface, wherein the outer surface of the electrode body located between the two electrode end surfaces is the electrode annular surface.

[0010] Beneficial effects: The end covering part includes a cylindrical surface covering the electrode annular surface and an annular surface covering the electrode end surface, which can facilitate the fixed installation of the end covering part and ensure the covering effect on the edge of the electrode end surface.

[0011] In an optional embodiment, a notch is provided on the annular surface, and the notch is used to avoid the pole ear.

[0012] Beneficial effect: The setting of the notch can avoid the tab and ensure the fixed flatness of the end cover.

[0013] In an optional embodiment, each of the two electrode end surfaces is covered with an end covering portion, and the two end covering portions respectively cover a portion of the two electrode end surfaces.

[0014] Beneficial effect: The two electrode end surfaces are each covered with an end covering portion, which can further reduce the probability of metal foreign matter entering the interior of the electrode body, thereby reducing the probability of metal foreign matter affecting the performance of the electrode assembly.

[0015] In an optional embodiment, the protective member further includes a side covering portion, the side covering portion is capable of covering the electrode annular surface, and the side covering portion is connected to the end covering portion.

[0016] Beneficial effect: The side covering portion is wrapped around the electrode ring surface, which can protect the diaphragm on the electrode ring surface and prevent metal foreign matter of different particle sizes free in the electrolyte from damaging the diaphragm on the electrode ring surface due to the shaking of the electrode body or the relative movement between adjacent electrode bodies, thereby preventing the occurrence of micro-short circuits of the electrode body and excessive self-discharge.

[0017] In an optional embodiment, the protective member includes a plurality of sheet units, each of which includes a main surface, an end surface and two overlapping surfaces, the end surface being connected to one end of the main surface along the height direction of the electrode body, the two overlapping surfaces being connected at both ends along the circumference of the electrode body, a plurality of the sheet units being connected end to end in sequence along the circumference of the electrode body, the adjacent overlapping surfaces on two adjacent sheet units being overlapped, a plurality of the main surfaces being spliced ​​to form the side covering portion, and the end surfaces located at the same end of the electrode body being spliced ​​to form the end covering portion.

[0018] Beneficial effects: The protective member is composed of a plurality of sheet units connected end to end, has a simple structural scheme, and is easy to install on the electrode body.

[0019] In an optional implementation, the protective member is adhesive tape.

[0020] Beneficial effect: The protective piece is adhesive tape, which is easy to bond to the electrode body and easy to operate.

[0021] In a second aspect, the utility model further provides a battery cell, comprising a shell assembly and at least one electrode assembly as described in any one of the first aspects, wherein the electrode assembly is arranged in the shell assembly.

[0022] Beneficial effects: Since the battery cell includes an electrode assembly, it has the same effects as the electrode assembly and will not be described in detail herein.

[0023] In a third aspect, the present invention further provides a battery pack, comprising a plurality of battery cells as described in the second aspect.

[0024] Beneficial effect: Since the battery pack includes a battery cell, it has the same effect as the battery cell, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 This is an axial side view of an electrode assembly according to an embodiment of the utility model;

[0027] Figure 2 It is an axial side view of an electrode assembly of an embodiment of the utility model from another perspective;

[0028] Figure 3 This is an axial side view of an electrode body in an electrode assembly according to an embodiment of the utility model;

[0029] Figure 4 This is an axial side view of a sheet unit in an electrode assembly according to an embodiment of the utility model;

[0030] Figure 5 It is an axial side view of a sheet unit with a notch in an electrode assembly according to an embodiment of the utility model.

[0031] Description of reference numerals:

[0032] 1. Electrode body; 2. Protective parts; 3. Electrode ears;

[0033] 101, electrode end surface; 102, electrode annular surface;

[0034] 201, end covering part; 202, side covering part; 203, sheet unit;

[0035] 2011, torus; 2012, cylinder; 2013, notch;

[0036] 2031. Main body surface; 2032. Overlapping surface; 2033. End surface. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the utility model.

[0038] In related technologies, with the rapid development of electric vehicles and energy storage markets, the application scenarios of lithium-ion batteries are becoming more and more extensive. Compared with other batteries, they have great advantages in size and capacity. Power cells are the core components of lithium batteries, and their yield and safety performance have also received widespread attention.

[0039] During the assembly process of lithium-ion batteries, the tabs need to be ultrasonically welded together and then laser welded to the adapter. However, ultrasonic welding of the tabs will produce scattered metal foreign matter, which has a size of tens to hundreds of microns and forms particle or line shapes. The scattered metal foreign matter will enter the interior of the winding core and form micro short-circuit points along with the flow of free electrolyte, which will seriously affect the performance of the electrode assembly.

[0040] In order to solve the above technical problems, the utility model provides an electrode assembly, a battery cell and a battery pack to reduce the probability of metal foreign matter generated by laser welding affecting the performance of the electrode assembly.

[0041] Combine the following Figures 1 to 5 , describing an embodiment of the utility model.

[0042] According to an embodiment of the present invention, on the one hand, an electrode assembly is provided, such as Figures 1 to 3 As shown, it includes an electrode body 1 and a protective member 2. Specifically, the protective member 2 is adhesive tape, or any other tape that can block metal foreign particles generated by laser welding; Figure 3As shown, the two end surfaces of the electrode body 1 along its height direction are electrode end surfaces 101; the protective member 2 includes an end covering portion 201, and the electrode end surface 101 provided with the pole ear 3 is provided with the end covering portion, and the end covering portion 201 can cover a part of the electrode end surface 101. Specifically, the pole ear 3 is a positive pole ear and / or a negative pole ear, that is, the positive pole ear and the negative pole ear can be located on one electrode end surface 101 at the same time, or can be located on two electrode end surfaces 101 respectively.

[0043] It is worth noting that the axial direction of the electrode body 1 is the winding axis direction of the electrode body 1 .

[0044] It should be noted that the electrode body 1 can be any type of winding core, such as a cylindrical winding core, an elliptical winding core, a square winding core, etc.; the protective member 2 can be attached to the electrode end surface 101 by gluing.

[0045] Specifically, the end covering portion 201 can cover a portion of the electrode end surface 101. The covering shape of the end covering portion 201 on the electrode end surface 101 can be any shape, such as a triangle, a semicircle, a square, etc., as long as it can cover a portion of the electrode end surface 101. Preferably, in one embodiment, the end covering portion 201 is annular; in this embodiment, the end covering portion 201 is annular, has a simple shape, and can occupy a larger area of ​​the electrode end surface 101, which can improve the blocking effect on metal foreign matter and further reduce the probability of metal foreign matter affecting the performance of the electrode assembly.

[0046] In this embodiment, the end covering portion 201 of the protective member 2 is used to partially cover the electrode end surface 101 provided with the pole ear 3. When the electrode body 1 is laser-welding the pole ear 3, it is possible to block the scattered metal foreign matter during the laser welding, thereby reducing the probability of metal foreign matter entering the electrode body 1, thereby reducing the probability of metal foreign matter affecting the performance of the electrode assembly. The end covering portion 201 only partially covers the electrode end surface 101 and will not affect the replenishment of the electrode body 1 by the external electrolyte.

[0047] In one embodiment, Figure 1 and Figure 2 As shown, the end covering portion 201 includes an annular surface 2011 and a cylindrical surface 2012, the annular surface 2011 is a circular annular surface, and the cylindrical surface 2012 is a cylindrical surface with two ends open. The outer edge of the annular surface 2011 is connected to the edge of one end of the cylindrical surface 2012, the annular surface 2011 contacts the electrode end surface 101, and the cylindrical surface 2012 contacts the electrode annular surface 102, wherein, as shown in FIG. Figure 3 As shown, the outer surface of the electrode body 1 located between the two electrode end surfaces 101 is the electrode annular surface 102 .

[0048] Specifically, the width of the annular surface 2011 is T mm of the thickness of the electrode body 1, and the thickness of the annular surface 2011 is (T / 2-3) mm; preferably, 5 mm to 8 mm.

[0049] In this embodiment, the end cover 201 includes a cylindrical surface 2012 covering the electrode annular surface 102 and an annular surface 2011 covering the electrode end surface 101, which can facilitate the fixed installation of the end cover 201 and ensure the covering effect on the edge of the electrode end surface 101.

[0050] In one embodiment, Figure 1 and Figure 5 As shown, a notch 2013 is provided on the annular surface 2011, and the notch 2013 is used to avoid the pole ear 3. Specifically, the shape of the notch 2013 can be set according to the shape of the pole ear 3, such as semicircular or directional. This solution mainly deals with the pole ear 3 located at the edge of the electrode end surface 101; in this embodiment, the setting of the notch 2013 can avoid the pole ear 3 and ensure the fixed flatness of the end cover 201.

[0051] In one embodiment, Figure 1 and Figure 2 As shown, each of the two electrode end surfaces 101 is coated with an end covering portion 201, and the two end covering portions 201 respectively cover a portion of the two electrode end surfaces 101, that is, both ends of the electrode body 1 are partially coated; in this embodiment, each of the two electrode end surfaces 101 is coated with an end covering portion 201, which can further reduce the probability of metal foreign matter entering the interior of the electrode body 1, thereby reducing the probability of metal foreign matter affecting the performance of the electrode assembly.

[0052] In one embodiment, the protective member 2 also includes a side covering portion 202, which can cover the electrode ring surface 102, and the side covering portion 202 is connected to the end covering portion 201; the side covering portion 202 is mainly provided to protect the electrode ring surface 102. In this embodiment, the side covering portion 202 is covered on the electrode ring surface 102, and can protect the diaphragm of the electrode ring surface 102 to prevent metal foreign matter of different particle sizes free in the electrolyte from damaging the diaphragm of the electrode ring surface 102 due to the shaking of the electrode body 1 or the relative movement between adjacent electrode bodies 1, so as to prevent the occurrence of micro-short circuit of the electrode body 1 and excessive self-discharge.

[0053] In one embodiment, Figure 1 , Figure 2 , Figure 4 and Figure 5As shown, the protective member 2 includes a plurality of sheet units 203, the sheet unit 203 includes a main surface 2031, an end surface 2033 and two overlapping surfaces 2032, the end surface 2033 is connected to one end of the main surface 2031 along the height direction of the electrode body 1, the two overlapping surfaces 2032 are connected at both ends along the circumference of the electrode body 1, the plurality of sheet units 203 are connected end to end in sequence along the circumference of the electrode body 1, the adjacent overlapping surfaces 2032 on two adjacent sheet units 203 are overlapped, the plurality of main surfaces 2031 are spliced ​​to form the side covering portion 202, and the end surfaces 2033 located at the same end of the electrode body 1 are spliced ​​to form the end covering portion 201.

[0054] Specifically, the number of the sheet units 203 can be selected and set according to actual needs, and can be any one of 2, 3, 4 and 5, preferably 2; the length of the overlapping surface 2032 along the axial direction of the electrode body 1 is 3mm to 6mm.

[0055] It is worth noting that there can be one end surface 2033 connected to one end of the main surface 2031 along the height direction of the electrode body 1; or there can be two end surfaces 2033 connected to both ends of the main surface 2031 along the height direction of the electrode body 1 respectively.

[0056] The following describes the coating process of the electrode body 1 by taking the protective member 2 including two sheet units 203 as an example, wherein the sheet unit 203 is made of film; Figures 1 to 5 As shown, first, the main surface 2031 and the two overlapping surfaces 2032 of a sheet unit 203 are attached to a part of the electrode ring surface 102, and then the two end surfaces 2033 are bent and attached to the two electrode end surfaces 101 respectively, and then the main surface 2031 of another sheet unit 203 is attached to the other part of the electrode ring surface 102, and the two overlapping surfaces 2032 on it are overlapped and attached with the two overlapping surfaces 2032 on the sheet unit 203 pasted first, and then the two end surfaces 2033 on the later-attached sheet unit 203 are bent and attached to the two electrode end surfaces 101 respectively, so that the two main surfaces 2031 on the two sheet units 203 form a side covering portion 202, and the two end surfaces 2033 located at the same end form an end covering portion 201; in this embodiment, the protective member 2 is composed of a plurality of sheet units 203 connected end to end, the structural scheme is simple, and it is easy to install on the electrode body 1.

[0057] In a second aspect, the utility model further provides a battery cell, comprising a shell assembly and at least one electrode assembly according to any one of the first aspects, wherein the electrode assembly is disposed in the shell assembly.

[0058] It should be noted that the shell assembly may contain one electrode assembly or multiple electrode assemblies connected in series and / or in parallel.

[0059] In this embodiment, since the battery cell includes an electrode assembly, it has the same effect as the electrode assembly and is not described in detail herein.

[0060] In a third aspect, the present invention further provides a battery pack, comprising a plurality of battery cells in the second aspect.

[0061] Specifically, multiple battery cells are connected in series and / or in parallel in a battery pack to form a power supply unit of the battery pack; the battery pack can be used in new energy vehicles and various devices that require power supply.

[0062] In this embodiment, since the battery pack includes a battery cell, it has the same effect as the battery cell and is not described in detail herein.

[0063] Although the embodiments of the present invention are described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. An electrode assembly, characterized in that: include: An electrode body (1), wherein both end surfaces of the electrode body (1) in the height direction are electrode end surfaces (101); as well as A protective member (2), the protective member (2) comprising an end covering portion (201), the end covering portion (201) being arranged on the electrode end surface (101) provided with the electrode lug (3), the end covering portion (201) being capable of covering a portion of the electrode end surface (101).

2. The electrode assembly according to claim 1, characterized in that: The end covering portion (201) is annular.

3. The electrode assembly according to claim 1, characterized in that: The end covering portion (201) comprises an annular surface (2011) and a cylindrical surface (2012); the outer edge of the annular surface (2011) is connected to the edge of one end of the cylindrical surface (2012); the annular surface (2011) contacts the electrode end surface (101); and the cylindrical surface (2012) contacts the electrode annular surface (102); wherein the outer surface of the electrode body (1) located between the two electrode end surfaces (101) is the electrode annular surface (102).

4. The electrode assembly according to claim 3, characterized in that: The annular surface (2011) is provided with a notch (2013), and the notch (2013) is used to avoid the pole ear (3).

5. The electrode assembly according to claim 1, characterized in that: The two electrode end surfaces (101) are each covered with an end covering portion (201), and the two end covering portions (201) respectively cover a portion of the two electrode end surfaces (101).

6. The electrode assembly according to claim 3 or 4, characterized in that: The protective member (2) further comprises a side covering portion (202), wherein the side covering portion (202) is capable of covering the electrode annular surface (102), and the side covering portion (202) is connected to the end covering portion (201).

7. The electrode assembly according to claim 6, characterized in that: The protective member (2) comprises a plurality of sheet units (203), wherein the sheet units (203) comprise a main body surface (2031), an end surface (2033) and two overlapping surfaces (2032); the end surface (2033) is connected to one end of the main body surface (2031) along the height direction of the electrode body (1); the two overlapping surfaces (2032) are connected at both ends along the circumference of the electrode body (1); the plurality of sheet units (203) are connected end to end in sequence along the circumference of the electrode body (1); the overlapping surfaces (2032) on two adjacent sheet units (203) are arranged in an overlapping manner; the plurality of main body surfaces (2031) are spliced ​​to form the side covering portion (202); and the end surfaces (2033) located at the same end of the electrode body (1) are spliced ​​to form the end covering portion (201).

8. The electrode assembly according to any one of claims 1 to 5, characterized in that: The protective piece (2) is adhesive tape.

9. A battery cell, characterized in that: include: Shell assembly; as well as, At least one electrode assembly according to any one of claims 1 to 8, wherein the electrode assembly is disposed within the housing assembly.

10. A battery pack, characterized in that: include: A plurality of battery cells as claimed in claim 9.

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