Secondary battery, battery pack, and electronic device

Abstract

The embodiment of the utility model provides a secondary battery, a battery pack and an electronic device, the secondary battery comprises: an electrode assembly, the electrode assembly comprises a positive pole piece, a first diaphragm, a negative pole piece and a second diaphragm, and the positive pole piece, the first diaphragm, the negative pole piece and the second diaphragm are sequentially laminated and then wound to form the electrode assembly; the insulating layer is used for fixing the ending end of the electrode assembly, the insulating layer comprises an adhesive layer and a base material layer, and the adhesive layer faces the electrode assembly; and the identification piece is positioned between the adhesive layer and the base material layer. According to the technical scheme, at least the identification piece can be prevented from being abraded or corroded.

Description

Technical Field

[0001] The utility model relates to a secondary battery, a battery pack and an electronic device. Background Art

[0002] In the field of new energy power batteries, the application of secondary batteries is becoming more and more extensive. For example, secondary batteries (such as lithium-ion batteries) can be applied to electronic devices such as cars, energy storage, mobile phones, tablets, wearable devices, mobile power supplies, electronic cigarettes, digital products, power tools, power devices, energy storage devices, etc. One type of secondary battery is a cylindrical battery, which includes a housing and an electrode assembly. The electrode assembly includes a positive electrode sheet, a first diaphragm, a negative electrode sheet and a second diaphragm, which are stacked in sequence and wound into an electrode assembly, and the end of the electrode assembly is fixed by an insulating layer and then encapsulated in a housing. However, existing secondary batteries still need further improvement in some aspects. Utility Model Content

[0003] In view of the problems existing in the related art, the purpose of the present invention is to provide a secondary battery, a battery pack and an electronic device, so as to at least avoid the wear or corrosion of the identification parts used for the electrode assembly.

[0004] To achieve the above-mentioned purpose, an embodiment of the present application provides a secondary battery, including an electrode assembly, wherein the electrode assembly includes a positive electrode sheet, a first separator, a negative electrode sheet, and a second separator, which are stacked and wound in sequence to form the electrode assembly. The secondary battery also includes: an insulating layer for fixing the end of the electrode assembly, the insulating layer including a glue layer and a substrate layer, wherein the glue layer faces the electrode assembly; and an identification member located between the glue layer and the substrate layer.

[0005] In some embodiments, the identification element includes a two-dimensional code facing the substrate layer.

[0006] In some embodiments, the substrate layer is a transparent or translucent substrate layer.

[0007] In some embodiments, the insulating layer surrounds the electrode assembly in a winding direction of the electrode assembly.

[0008] In some embodiments, the identification member is spaced apart from the starting end and the ending end of the insulating layer.

[0009] In some embodiments, the identification member has a height in the height direction of the electrode assembly and a length in the winding direction of the electrode assembly, wherein the height and length of the identification member are not greater than 8% of the height of the insulating layer in the height direction and not less than 1% of the height of the insulating layer.

[0010] In some embodiments, the secondary battery further comprises: a shell accommodating the electrode assembly; wherein the substrate layer of the insulating layer separates the identification element from the shell.

[0011] In some embodiments, in the height direction of the electrode assembly, the identification member is located in the middle of the insulating layer; the secondary battery is a cylindrical battery, and a ratio of the height to the diameter of the cylindrical battery is in the range of 1.7-3.3.

[0012] An embodiment of the present application further provides a battery pack, which includes any one of the secondary batteries described above.

[0013] An embodiment of the present application further provides an electronic device, which includes at least one of the secondary battery of any one of the above items and the battery pack.

[0014] The beneficial technical effects of the utility model are:

[0015] By arranging the identification component between the adhesive layer and the substrate layer, it is possible to avoid wear or corrosion of the identification component, for example, to avoid wear or corrosion of the identification component during the rotation of the electrode assembly or under extreme working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 A schematic diagram showing a case where the electronic device according to an embodiment of the present application is a vehicle.

[0018] Figure 2 A perspective view of a secondary battery according to an embodiment of the present application is shown.

[0019] Figure 3 A cross-sectional view of a secondary battery according to an embodiment of the present application is shown.

[0020] Figure 4 is a schematic cross-sectional view of an electrode assembly of a secondary battery according to an embodiment of the present application.

[0021] Figure 5 It is a schematic top view of the insulating layer when it is laid flat according to an embodiment of the present application.

[0022] Figure 6 It is a schematic diagram of cutting a single insulation layer from a continuous insulation layer. DETAILED DESCRIPTION

[0023] In order to better understand the spirit of the embodiments of the present application, some preferred embodiments of the present application are further described below.

[0024] The embodiments of the present application will be described in detail below. In the full text of the present application specification, the same or similar components and components with the same or similar functions are represented by similar reference numerals. The embodiments of the accompanying drawings described herein are illustrative, graphical, and are used to provide a basic understanding of the present application. The embodiments of the present application should not be interpreted as limiting the present application.

[0025] As used herein, the terms "substantially," "substantially," "essentially," and "about" are used to describe and account for small variations. When used in conjunction with an event or circumstance, the terms may refer to instances where the event or circumstance occurred precisely as well as instances where the event or circumstance occurred very approximately.

[0026] 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 derivative terms (such as "horizontally", "downwardly", "upwardly", etc.) should be interpreted as referring to the directions described in the discussion or depicted in the drawings. These relative terms are only used for convenience of description and do not require that the present application be constructed or operated in a specific direction.

[0027] For convenience of description, “first”, “second”, “third”, etc. may be used herein to distinguish different components in one figure or a series of figures. “First”, “second”, “third”, etc. are not intended to describe the corresponding components.

[0028] See also Figure 1 For the convenience of explanation, the following embodiments are described by taking the electronic device as a vehicle 1000 as an example. However, it is not difficult to understand that the electronic device provided by the present application is not limited to a vehicle, and the electronic device may also be a vehicle, a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, an electric tool, etc.

[0029] The vehicle 1000 is provided with a battery pack 1002 inside, and the battery pack 1002 can be arranged at the bottom of the vehicle body 1001 (such as Figure 1 The battery pack 1002 may be used to power the vehicle 1000. For example, the battery pack 1002 may be used as an operating power source or a driving power source for the vehicle 1000. The battery pack 1002 may include a plurality of cylindrical batteries (such as Figure 2 A secondary battery 100) and a housing for accommodating a plurality of cylindrical batteries.

[0030] Figure 21 shows a perspective view of a secondary battery 100 according to an embodiment of the present application, Figure 3 1 shows a cross-sectional view of a secondary battery 100 according to an embodiment of the present application. In this embodiment, the secondary battery 100 is a cylindrical battery. Figure 2 and Figure 3 , the secondary battery 100 may include an electrode assembly 120, an electrolyte, a shell 200 and a cover plate 202. The shell 200 and the cover plate 202 are components that jointly accommodate the electrode assembly 120 and the electrolyte. The material of the shell 200 can be any one of a variety of available materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. The shell 200 can be cylindrical and define a accommodating cavity, and the electrode assembly 120 is arranged in the accommodating cavity. The diameter of the shell 200 can be determined according to the specific size of the electrode assembly 120, such as 18mm, 21mm, 46mm, etc. In some embodiments, the secondary battery 100 is a 4680 cylindrical battery, wherein the diameter of the shell 200 is 46mm.

[0031] The housing 200 can be connected to the negative electrode of the electrode assembly 120. The housing 200 may have a mounting opening 205 at one end along the height direction (Z direction), and the cover plate 202 is disposed at the mounting opening 205 and blocks the accommodating cavity. The secondary battery 100 may also have a pole 208 at one end relative to the cover plate 202, and the pole 208 may be connected to the positive electrode of the electrode assembly 120. It should be understood that the pole 208 and the housing 200 are in an insulated matching state to avoid battery short circuit.

[0032] See also Figure 3 , a crimping portion 203 protruding inward is also provided at a position adjacent to the mounting opening 205 of the housing 200. Along the height direction of the secondary battery 100, the electrode assembly 120 is arranged between the end wall 111 and the crimping portion 203, and the crimping portion 203 can limit the axial movement (movement in the height direction) of the electrode assembly 120 between the end wall 111 of the housing 200 and the crimping portion 203. A weak portion may be provided on the cover plate 202. When the battery undergoes thermal runaway, the high-temperature and high-pressure emissions inside can be discharged to the outside from the bottom of the battery, breaking through the weak portion on the cover plate 202, thereby achieving good guidance of the emissions.

[0033] The electrode assembly 120 may include a positive electrode sheet, a first separator, a negative electrode sheet, and a second separator that are stacked and wound in sequence. The electrode assembly 120 is provided with a positive electrode tab and a negative electrode tab at both ends of the height direction of the secondary battery 100. In some embodiments, the positive electrode tab faces the end wall 111 and is electrically connected to the pole 208 so that the pole 208 is positively charged; the negative electrode tab faces the mounting port 205, and the housing 200 is electrically connected to the negative electrode tab so as to be negatively charged. However, in other embodiments, the negative electrode tab may be connected to the pole 208, and the positive electrode tab may be connected to the housing 200.

[0034] The positive electrode plate may include a positive electrode current collector and a positive electrode active material layer coated on both sides of the positive electrode current collector. The portion of the positive electrode current collector not coated with the positive electrode active material layer constitutes a positive electrode tab. The negative electrode plate may include a negative electrode current collector and a negative electrode active material layer coated on both sides of the negative electrode current collector. The portion of the negative electrode current collector not coated with the negative electrode active material layer constitutes a negative electrode tab. Taking a lithium-ion battery as an example, the material of the positive electrode current collector may be aluminum, the positive electrode active material layer may include a positive electrode active material, and the positive electrode active material may be lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganese oxide, etc. The material of the negative electrode current collector may be copper, the negative electrode active material layer may include a negative electrode active material, and the negative electrode active material may be carbon or silicon, etc. In some embodiments, the material of the first diaphragm and the second diaphragm may be, for example, PP (polypropylene) or PE (polyethylene).

[0035] Usually, the end of the electrode assembly 120 is fixed by an insulating layer and then encapsulated in the housing 200. In addition, an identification piece is usually provided on the insulating layer for tracing the electrode assembly. However, during production on the production line, the electrode assembly 120 is bonded to the electrode assembly 120 by rotating the insulating layer, so it is easy to cause wear on the identification piece; or, under extreme operating conditions such as high temperature inside the secondary battery, the identification piece is also easily corroded, which will cause the problem of being unable to be traced.

[0036] Figure 4 is a schematic cross-sectional view of an electrode assembly 120 of a secondary battery according to an embodiment of the present application. Figure 4 The electrode assembly 120 may include a positive electrode sheet 121 , a first separator 141 , a negative electrode sheet 122 , and a second separator 142 . The positive electrode sheet 121 , the first separator 141 , the negative electrode sheet 122 , and the second separator 142 are sequentially stacked and wound to form the electrode assembly 120 .

[0037] In addition, the secondary battery may further include an insulating layer 300, which may be used to fix the end 120e of the electrode assembly 120. In one embodiment, the end of the first separator 141 and the end of the second separator 124 are aligned with each other and configured as the end 120e of the electrode assembly 120.

[0038] In this embodiment, the insulating layer 300 surrounds the electrode assembly 120 in the winding direction of the electrode assembly 120, thereby fixing the tail end 120e of the electrode assembly 120. In this embodiment, the insulating layer 300 starts to adhere to the electrode assembly 120 from its starting end 300s, and is wound along the same winding direction as the electrode assembly 120, passing through the tail end 120e of the electrode assembly 120, until the tail end 300e is adhered to the insulating layer 300. Configuring the insulating layer 300 to surround the electrode assembly 120 can prevent the electrode assembly 120 from being attached to other components (such as Figure 3 The insulating layer 300 is in contact with the outer shell 200 in the electrode assembly 120, thereby providing better protection and insulation for the electrode assembly 120. In other embodiments, the insulating layer 300 may also be partially bonded to the electrode assembly 120, and the insulating layer 300 crosses the end 120e of the electrode assembly 120 to bond the second diaphragm 142, thereby fixing the end 120e of the electrode assembly 120.

[0039] Figure 5 FIG. 3 is a top view schematic diagram of the insulating layer 300 when it is laid flat according to an embodiment of the present application. Figure 5 , the insulating layer 300 may include a glue layer 302 and a substrate layer 304, and the glue layer 302 and the substrate layer 304 may overlap each other. The glue layer 302 faces the electrode assembly 120 (see Figure 4 ) and bonded to the electrode assembly 120.

[0040] In some embodiments, the base material layer 304 of the insulating layer 300 may be formed of PP, PE, PET (polyethyleneterephthalate), PVC (Polyvinyl chloride) or other polymer materials. In some embodiments, the material of the adhesive layer 302 may be any suitable adhesive material.

[0041] In addition, the identification member 350 may be located between the adhesive layer 302 and the substrate layer 304. The identification member 350 may carry detectable identification information for identifying the corresponding production information of the corresponding electrode assembly 120, so as to achieve the purpose of tracing the source, etc. The present application sets the identification member 350 between the adhesive layer 302 and the substrate layer 304 to avoid wear or corrosion of the identification member 350, for example, to avoid wear or corrosion of the identification member 350 during the rotation process during production or under extreme working conditions.

[0042] In some embodiments, in combination Figure 5 and Figure 3 As shown, the base material layer 304 of the insulating layer 300 can separate the identification member 350 from the housing 200. Thus, the identification member 350 can be prevented from contacting the housing 200, which can further prevent the identification member 350 from being worn or corroded.

[0043] Continue to refer Figure 5 As shown, in some embodiments, the identification member 350 may include a two-dimensional code facing the substrate layer 304. By detecting the two-dimensional code, the corresponding production information of the corresponding electrode assembly 120 can be identified to achieve the purpose of tracing the source. In some embodiments, an image acquisition device can be used to identify the two-dimensional code. For example, a CCD (Charge Coupled Device) camera can be used to identify the two-dimensional code. By using an identification member 350 with a two-dimensional code, an image acquisition device can be used to identify the two-dimensional code, thereby making identification more convenient.

[0044] In some embodiments, the substrate layer 304 is a transparent substrate layer. In some embodiments, the substrate layer 304 may also be a translucent substrate layer. The transparency of the translucent substrate layer refers to the transparency at which the image acquisition device (such as CCD) can correctly identify the two-dimensional code. By configuring the substrate layer 304 to be transparent or translucent, the identification information (such as the two-dimensional code) carried by the identification element 350 can be identified through the substrate layer 304. In this way, the identification element 350 can be easily identified.

[0045] In some embodiments, the identification member 350 is spaced apart from both the starting end 300s and the ending end 300e of the insulating layer 300. It should be understood that after the insulating layer 300 surrounds the electrode assembly 120, if the outermost insulating layer 300 overlaps the identification member 350, it will affect the identification of the identification member 350. By spacing the identification member 350 from the starting end 300s and the ending end 300e, the problem of overlapping of the insulating layer 300 and the identification member 350 and affecting the identification can be avoided.

[0046] In some embodiments, the identification member 350 has a height H1 in the height direction (direction Z) of the electrode assembly 120 and a height H2 in the winding direction (direction Z) of the electrode assembly 120. Figure 5 In some embodiments, the height H1 and length L1 of the identification member 350 are not greater than 8% of the height H2 of the insulating layer 300 and not less than 1% of the height H2. If the height H1 and / or length L1 of the identification member 350 is greater than 8% of the height H2, or the height H1 and / or length L1 of the identification member 350 is less than 1% of the height H2, the identification member 350 (e.g., its QR code) may not be correctly identified after the insulating layer 300 is wound on the electrode assembly 120. By adopting such an identification member 350 of appropriate size, the identification member 350 can still be correctly identified after the insulating layer 300 is wound on the electrode assembly 120.

[0047] In some embodiments, the height H1 may be in the range of (6±1) mm, and the length L1 may be in the range of (6±1) mm. In some embodiments, the height H2 of the insulating layer 300 may be in the range of (108±0.8) mm. In some embodiments, the length L2 of the insulating layer 300 in the direction X of the electrode assembly 120 may be in the range of (137±1.5) mm.

[0048] In some embodiments, the identification member 350 is located at an intermediate position between the starting end 300s and the ending end 300e of the insulating layer 300, that is, the distance D1 between the identification member 350 and the starting end 300s may be substantially equal to the distance D2 between the identification member 350 and the ending end 300e. In some embodiments, D1 and D2 may be within the range of (65.5±1) mm, respectively. By arranging the identification member 350 at an intermediate position between the starting end 300s and the ending end 300e, it may be advantageous to avoid wear or corrosion of the identification member 350.

[0049] In some embodiments where the secondary battery is a cylindrical battery, the ratio of the height to the diameter of the cylindrical battery is in the range of 1.7-3.3. Figure 3 The height of the cylindrical battery refers to the distance from the end wall 111 to the cover plate 202 in the direction Z, that is, the height excluding the protruding pole 208; the diameter of the cylindrical battery refers to the diameter of the housing 200 (that is, the outer diameter, including the thickness of the housing 200). Figure 5 In some embodiments, such as the embodiment where the secondary battery is a cylindrical battery, the identification member 350 is located in the middle of the insulating layer 300 in the height direction. The middle position is specifically: the center position of the identification member 350 is ±10% of the center position of the height of the insulating layer 300. By setting the identification member 350 in the middle position in the height direction, it can be beneficial to avoid wear or corrosion of the identification member 350, and at this middle position, it is convenient for CCD recognition, and the middle position is not easily affected by heat such as laser welding at both ends, and because the bare battery cell is often clamped at both ends during assembly, the middle position can avoid wear during clamping.

[0050] In some embodiments, the distances D3 and D4 between the identification element 350 and the opposite edges of the insulating layer 300 in the height direction may be substantially equal. In some embodiments, D3 and D4 may be within the range of (51±1.5) mm, respectively.

[0051] See also Figure 6It should be understood that the insulating layer 300 for a single electrode assembly 120 is obtained by cutting the continuous insulating layer 300'. In the production line, in order to cut the continuous insulating layer 300', a cutting mark 360 is required to be set on the continuous insulating layer 300'. Cutting is performed at each cutting mark 360, so as to obtain the insulating layer 300 for a single electrode assembly 120 between adjacent cutting marks 360. The distance between adjacent cutting marks 360 is the above-mentioned Figure 5 The length L2 of the insulating layer 300 is described. In some embodiments, the cutting mark 360 may be closer to the bottom edge of the continuous insulating layer 300'. For example, the distance D5 between the cutting mark 360 and the bottom edge of the continuous insulating layer 300' may be, for example, in the range of (25±1) mm.

[0052] In summary, the present application can avoid wear or corrosion of the identification part 350 by setting the identification part 350 between the glue layer 302 and the substrate layer 304, for example, avoid wear or corrosion of the identification part 350 during the rotation of the electrode assembly 120 or under extreme working conditions. Moreover, such beneficial effects have been demonstrated through electro-hydraulic testing. In the electrolyte test, the identification part set between the glue layer and the substrate layer of the insulating layer will fall off when rubbed with tweezers after being subjected to electrolyte resistance (85°C and 24 hours); the identification part will not fall off when rubbed with tape. It can be seen that by setting the identification part between the glue layer and the substrate layer of the insulating layer, effects similar to those caused by friction with tape can be avoided.

[0053] The embodiments of the present application further provide a battery pack (such as the battery pack 1002 described above), which may include the secondary battery 100 of any one of the embodiments described above, and the battery pack may have the beneficial effects described above with respect to the secondary battery 100 .

[0054] An embodiment of the present application also provides an electronic device, which may include the secondary battery 100 of any one of the above embodiments, and / or the battery pack 1002 of any one of the above embodiments, and the electronic device may have the beneficial effects described above regarding the secondary battery 100 and / or the battery pack 1002.

[0055] The above description is only the preferred embodiment of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A secondary battery, characterized in that: include: An electrode assembly, the electrode assembly comprising a positive electrode sheet, a first separator, a negative electrode sheet, and a second separator, which are stacked in sequence and then wound to form the electrode assembly; An insulating layer, used to fix the tail end of the electrode assembly, the insulating layer comprising a glue layer and a substrate layer, wherein the glue layer faces the electrode assembly; The identification piece is located between the adhesive layer and the substrate layer.

2. The secondary battery according to claim 1, characterized in that: The identification element includes a two-dimensional code facing the substrate layer.

3. The secondary battery according to claim 2, characterized in that: The substrate layer is a transparent or semi-transparent substrate layer.

4. The secondary battery according to claim 1, characterized in that: The insulating layer surrounds the electrode assembly in a winding direction of the electrode assembly.

5. The secondary battery according to claim 1, characterized in that: The identification member is spaced apart from a starting end and a tail end of the insulating layer.

6. The secondary battery according to claim 1, characterized in that: The identification member has a height in the height direction of the electrode assembly and a length in the winding direction of the electrode assembly, wherein the height and the length of the identification member are both no greater than 8% of the height of the insulating layer in the height direction and no less than 1% of the height of the insulating layer.

7. The secondary battery according to claim 1, characterized in that: Also includes: A shell, accommodating the electrode assembly; Wherein, the substrate layer of the insulating layer separates the identification element from the shell.

8. The secondary battery according to claim 1, characterized in that: In the height direction of the electrode assembly, the identification member is located at the middle position of the insulating layer; The secondary battery is a cylindrical battery, and the ratio of the height to the diameter of the cylindrical battery is in the range of 1.7-3.

3.

9. A battery pack, characterized in that: A secondary battery comprising any one of claims 1 to 8.

10. An electronic device, characterized in that: The invention comprises at least one of the secondary battery according to any one of claims 1 to 8 and the battery pack according to claim 9.

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