Secondary battery, battery pack, and electronic device

Abstract

The secondary battery provided by the embodiment of the utility model comprises a positive pole piece, a first diaphragm, a negative pole piece and a second diaphragm which are sequentially laminated and then wound to form an electrode assembly, and the insulating film is wound and wrapped outside the electrode assembly, and the insulating film comprises a winding overlapping area which is overlapped with the insulating film. The utility model aims to provide a secondary battery, a battery pack and an electronic device, so as to at least avoid short circuit of the secondary battery and avoid corrosion inside the shell.

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, secondary batteries refer to rechargeable batteries, also known as renewable batteries or storage batteries. Unlike primary batteries, secondary batteries can be charged and discharged multiple times through reverse charging for reuse. Secondary batteries generally include square shell batteries, soft pack batteries and cylindrical batteries. Secondary batteries generally include electrode assemblies, shells, cover plates, etc. The electrode assembly includes positive electrode sheets, negative electrode sheets and separators located between the positive electrode sheets and the negative electrode sheets. These positive electrode sheets, negative electrode sheets and separators are stacked on each other and wound into electrode assemblies, which are then encapsulated in the shell. 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 short circuit of the secondary battery.

[0004] To achieve the above-mentioned purpose, an embodiment of the present application provides a secondary battery, comprising: a positive electrode plate, a first separator, a negative electrode plate and a second separator, which are stacked in sequence and wound to form an electrode assembly; an insulating film, which is wound and wrapped around the outside of the electrode assembly, and the insulating film includes a winding overlap area that overlaps with itself.

[0005] In some embodiments, the secondary battery further includes: a housing, the electrode assembly and the insulating film are sealed in the housing, and the insulating film is located between the electrode assembly and the housing.

[0006] In some embodiments, the winding overlap region does not overlap with the winding end section of the positive electrode sheet and the winding end section of the negative electrode sheet in the radial direction.

[0007] In some embodiments, along the winding direction, a size of the winding overlap region is greater than or equal to 0.01 mm and less than or equal to 145 mm.

[0008] In some embodiments, along the winding direction, a size of the winding overlap region is greater than or equal to 0.01 mm and less than or equal to 3 mm.

[0009] In some embodiments, on a side of the secondary battery opposite to the positive terminal, the insulating film exceeds the second separator along a height direction of the secondary battery, and the exceeding distance is greater than 0 mm and less than or equal to 1 mm.

[0010] In some embodiments, the winding start section of the insulating film is connected to the winding end section of the second separator, and is wound one circle from the winding end section of the second separator, and then connected to itself and forms a winding overlap region.

[0011] In some embodiments, the insulating film is an adhesive tape, and the insulating film is bonded to the wound end section of the second separator.

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

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

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

[0015] The insulating film of the present application is wound and wrapped around the outside of the electrode assembly and includes a winding overlap area that overlaps with itself, thereby avoiding short circuits caused by foreign matter piercing the diaphragm in non-overlapping areas during operation of the electrode assembly, thereby improving the ability of the secondary battery to prevent foreign matter. 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 The electrode assembly and insulating film of the prior art are shown.

[0021] Figure 5 The diagram shows a positive electrode sheet, a first separator, a negative electrode sheet, a second separator, and an insulating film of a secondary battery according to an embodiment of the present application.

[0022] Figure 6 The insulating film after expansion is shown.

[0023] Figure 7 The electrode assembly is shown after being wrapped by an insulating film. DETAILED DESCRIPTION

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] The utility model provides an electronic device 1000, which includes a battery pack 10. The working part of the electronic device 1000 is electrically connected to the battery pack 1002 to obtain power support. As an example, the electronic device 1000 is a vehicle, and the vehicle can be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, but is not limited to this. The working part is the vehicle body, and the battery pack 1002 is arranged at the bottom of the vehicle body, and provides power support for the driving of the vehicle or the operation of the electrical components in the vehicle. However, in some other embodiments, the electronic device 1000 can also be a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy and an electric tool, etc. Spacecraft include airplanes, rockets, space shuttles and spacecrafts, etc.; the working part can obtain the power of the battery pack 1002 and make corresponding work unit components, such as the fan blade rotation unit of the fan, the dust collection unit of the vacuum cleaner, etc. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools, and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. The present application embodiment does not impose any special restrictions on the above-mentioned electronic device 1000.

[0030] For the convenience of description, the following embodiments are described by taking the electronic device 1000 as a vehicle as an example. Figure 1 The vehicle is provided with a battery pack 1002 inside, and the battery pack 1002 can be provided at the bottom, head or tail of the vehicle body 1001. The battery pack 1002 can be used for power supply of the vehicle, for example, the battery pack 1002 can be used as an operating power source of the vehicle.

[0031] Figure 2 1 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, Figure 5 The figure shows a positive electrode sheet 10, a first separator 20, a negative electrode sheet 12, a second separator 22 and an insulating film 30 of a secondary battery 100 according to an embodiment of the present application. Figure 6 The insulating film 30 after expansion is shown. Figure 7The electrode assembly 120 wrapped by the insulating film 30 is shown. The electrode assembly 120 of the secondary battery 100 is mainly formed by winding and placing the positive electrode sheet 10 and the negative electrode sheet 12, and a first separator 20 and a second separator 22 are usually provided between the positive electrode sheet 10 and the negative electrode sheet 12. The positive electrode sheet 10 includes a positive electrode collector and a positive electrode active material layer, and the positive electrode active material layer is coated on the surface of the positive electrode collector; the positive electrode collector includes a positive electrode coating area and a positive electrode ear connected to the positive electrode coating area, the positive electrode coating area is coated with the positive electrode active material layer, and the positive electrode ear is not coated with the positive electrode active material layer. The negative electrode sheet 12 includes a negative electrode collector and a negative electrode active material layer, and the negative electrode active material layer is coated on the surface of the negative electrode collector; the negative electrode collector includes a negative electrode coating area and a negative electrode ear connected to the negative electrode coating area, the negative electrode coating area is coated with the negative electrode active material layer, and the negative electrode ear is not coated with the negative electrode active material layer. Taking lithium-ion batteries as an example, the material of the positive electrode current collector can be aluminum, and the positive electrode active material layer includes the positive electrode active material, which can be lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganese oxide. The material of the negative electrode current collector can be copper, and the negative electrode active material layer includes the negative electrode active material, which can be carbon or silicon. The material of the first diaphragm 20 and the second diaphragm 22 can be PP or PE. In order to protect and insulate the electrode assembly 120, an insulating film 30 can also be coated on the outside of the electrode assembly 120. The insulating film 30 can be synthesized from PP, PE, PET, PVC or other high molecular polymer materials.

[0032] In an example of the secondary battery of the utility model, the electrode assembly 120 is sealed and installed in 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 rolling groove 113, and the rolling groove 113 can limit the axial movement of the electrode assembly 120 between the end wall 111 and the rolling groove 113. The electrode assembly 120 is respectively provided with a first pole ear and a second pole ear at both ends of the height direction of the secondary battery 100, and the polarities of the first pole ear and the second pole ear are opposite, wherein the first pole ear faces the opening side, and the first pole ear is a negative pole ear. It should be noted that in other embodiments, the first pole ear can also be a positive pole ear, and the second pole ear can be a negative pole ear.

[0033] Existing technologies such as Figure 4 The insulating film 400 has a non-overlapping area 402. During the transportation of the electrode assembly 1205 in the prior art, there is a risk that foreign matter (such as burrs and debris generated during production) will pierce the diaphragm, causing the positive and negative electrodes to contact and short-circuit. Because the diaphragm is exposed to the outside, when the battery is in use, corrosive gas (such as HF) will be generated, causing the corrosive liquid to contact the shell, thereby corroding the inside of the shell.

[0034] The embodiment of the present application provides a secondary battery 100, including: a positive electrode plate 10, a first separator 20, a negative electrode plate 12, and a second separator 22, which are stacked in sequence and then wound to form an electrode assembly 120; an insulating film 30, which is wound and wrapped on the outside of the electrode assembly 120, and the insulating film 30 includes a winding overlap area 32 that overlaps with itself. The insulating film 30 of the present application is wound and wrapped on the outside of the electrode assembly 120 and includes a winding overlap area 32 that overlaps with itself, which avoids the situation in which foreign matter pierces the separator in the non-overlapping area during the operation of the electrode assembly 120, causing a short circuit, and increases the ability of the electrode assembly 120 of the secondary battery 100 to prevent damage by foreign matter.

[0035] In some embodiments, the secondary battery 100 further includes: a housing 200, an electrode assembly 120 and an insulating film 30 sealed in the housing 200, and the insulating film 30 is located between the electrode assembly 120 and the housing 200. The insulating film 30 of the embodiment of the present application includes a winding overlap area 32 overlapping with itself to prevent the side wall of the housing 200 from being corroded. In some embodiments, the material of the housing 200 is, for example, copper, iron, aluminum, steel, aluminum alloy, etc., preferably steel (such as SPCC), which has higher strength. In order to prevent the housing 110 from rusting during long-term use, a layer of rust-proof material such as metal nickel can also be plated on the surface of the housing 110. If the insulating film of the prior art has a non-overlapping area, the secondary battery 100 has an electrochemical reaction to produce corrosive gas, causing the inner wall of the housing 200 to be corroded and blackened. The possible reason is that in the prior art, because the positive and negative electrodes are corroded, the corrosive liquid passes through the area without the insulating film and contacts the housing. After direct contact, the housing is corroded. The embodiment of the present application avoids this situation.

[0036] In some embodiments, the winding overlap region 32 does not overlap with the winding end section of the positive electrode sheet 10 and the winding end section of the negative electrode sheet 12 in the radial direction. The position of the winding overlap region 32 in the embodiment of the present application avoids the winding end section of the positive electrode sheet 10 and the winding end section of the negative electrode sheet 12, reducing the extreme difference in the size of the secondary battery 100. In some embodiments, the secondary battery 100 is a cylindrical battery, and the winding overlap region 32 does not overlap with the winding end section of the positive electrode sheet 10 and the winding end section of the negative electrode sheet 12 in the diameter direction, thereby avoiding the winding end section of the positive electrode sheet 10 and the winding end section of the negative electrode sheet, and reducing the extreme difference in the diameter of the electrode assembly / bare cell (JR) 120 of the cylindrical battery after being wrapped by the insulating film 30.

[0037] In some embodiments, along the winding direction, the size of the winding overlap area 32 is greater than or equal to 0.01 mm and less than or equal to 145 mm, avoiding the situation where the insulating film 30 is peeled off at the winding overlap area 32. In some embodiments, along the winding direction, the size of the winding overlap area 32 is greater than or equal to 0.01 mm and less than or equal to 3 mm. The size of the winding overlap area 32 is greater than or equal to 0.01 mm to ensure that the insulating film 30 has a winding overlap area, increase adhesion, avoid process errors, etc. that cause the leakage electrode assembly 120 to come out, and do a good job of completely separating the electrode assembly 120 from the shell 200. The size of the winding overlap area 32 is less than or equal to 3 mm. When the optimal overlap size is met, the strength of the winding overlap area 32 is appropriate, and the secondary battery 100 can be effectively alleviated during use, even if there is appropriate expansion, thereby protecting the electrode assembly 120 of the secondary battery 100. If the size of the winding overlap area 32 is too large, for example, greater than 3 mm, the radial thickness of the electrode assembly 120 (the diameter in the embodiment of the cylindrical battery) will increase, and the energy density will be lost.

[0038] In some embodiments, the number of windings of the negative electrode sheet 12 from the winding start section is greater than or equal to 1. The greater the number of windings, the tighter the inner circle is, and it is less likely to cause the center hole to collapse.

[0039] In some embodiments, on the side of the secondary battery 100 opposite to the positive terminal 500, the insulating film 30 exceeds the second diaphragm 22 along the height direction of the secondary battery 100, and the exceeding distance is greater than 0 mm and less than or equal to 1 mm. The second diaphragm 22 is an outer ring diaphragm, and the insulating film 30 exceeds the second diaphragm 22 to better protect the electrode assembly 120.

[0040] In some embodiments, the winding start section of the insulating film 30 is connected to the winding end section of the second separator 22, and is wound one circle from the winding end section of the second separator 22, and then connected to itself to form a winding overlap area 32. The second separator 22 is located at the outermost circle of the electrode assembly 120, and the insulating film 30 is connected to the winding end section of the second separator 22, which pulls the electrode assembly 120 tighter to prevent the inner separator from loosening, thereby reinforcing the internal structure of the secondary battery 100.

[0041] In some embodiments, the insulating film 30 is an adhesive tape, and the insulating film 30 is bonded to the winding end section of the first diaphragm 20. The end section of the insulating film 30 can be bonded to itself in the winding overlap area 32, thereby preventing the insulating film 30 from peeling off in the winding overlap area 32.

[0042] See also Figure 6 In some embodiments, a mark hole 50 is provided on the insulating film 30 to ensure that the insulating film 30 is cut to a fixed length.

[0043] In some embodiments, the secondary battery 100 is a cylindrical battery, and the height (eg Figure 3 As shown, the ratio of the distance from the end wall 111 to the cover plate 130 to the diameter (outer diameter) is in the range of 1.7-3.3, for example, the height is 80 mm and the diameter is 46 mm; another example is the height is 15 mm and the diameter is 46 mm. In some embodiments, the secondary battery 100 is a 4680 cylindrical battery.

[0044] The embodiment of the present application further provides a battery pack 1002 including any one of the secondary batteries 100 described above.

[0045] The embodiment of the present application further provides an electronic device 1000 , comprising at least one of the secondary battery 100 described above and the battery pack 1002 described above.

[0046] 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: The positive electrode sheet, the first separator, the negative electrode sheet and the second separator are sequentially stacked and then wound to form an electrode assembly; An insulating film is wound and wrapped around the outside of the electrode assembly, and the insulating film includes a winding overlap area overlapping with the insulating film itself.

2. The secondary battery according to claim 1, characterized in that: Also includes: A shell is provided in which the electrode assembly and the insulating film are sealed, and the insulating film is located between the electrode assembly and the shell.

3. The secondary battery according to claim 1, characterized in that: The winding overlap area does not overlap with the winding end section of the positive electrode sheet and the winding end section of the negative electrode sheet in the radial direction.

4. The secondary battery according to claim 1, characterized in that: Along the winding direction, the size of the winding overlap area is greater than or equal to 0.01 mm and less than or equal to 145 mm.

5. The secondary battery according to claim 1, characterized in that: Along the winding direction, the size of the winding overlap area is greater than or equal to 0.01 mm and less than or equal to 3 mm.

6. The secondary battery according to claim 1, characterized in that: On the side of the secondary battery opposite to the positive terminal, the insulating film protrudes beyond the second separator along the height direction of the secondary battery, and the protruding distance is greater than 0 mm and less than or equal to 1 mm.

7. The secondary battery according to claim 1, characterized in that: The winding start section of the insulating film is connected to the winding end section of the second diaphragm, and is wound one circle from the winding end section of the second diaphragm, and then connected to itself to form the winding overlap area.

8. The secondary battery according to claim 7, characterized in that: The insulating film is an adhesive tape, and the insulating film is bonded to the winding end section of the second diaphragm.

9. A battery pack, characterized in that: A secondary battery comprising the secondary battery according to 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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