Secondary battery, battery pack, and electronic device

Abstract

The utility model provides a secondary battery which comprises a lamination body formed by sequentially laminating a positive pole piece, a diaphragm and a negative pole piece, and the length direction of the lamination body is the direction of leading out tabs of the positive pole piece and the negative pole piece; the lamination body is provided with two opposite narrow side surfaces in the width direction, adhesive tapes are respectively adhered to the two narrow side surfaces, the lamination body is provided with two opposite large surfaces in the thickness direction, each adhesive tape is provided with two extension parts which respectively extend to the two large surfaces, the size of each extension part meets the condition that 2x * d * z / y is greater than 1, x is the bonding force of the adhesive tapes and the diaphragm, and y is the bonding force of the adhesive tapes and the diaphragm. The unit of x is N / m, d is the size of the adhesive tape in the length direction, the unit of d is mm, y is the thickness of the lamination body, the unit of y is mm, and z is the size of the extension part in the width direction, and the unit of z is mm. The utility model aims to provide a secondary battery, a battery pack and an electronic device so as to at least ensure the fixation of a lamination body by an adhesive tape.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of secondary batteries, battery pack and electronic device. BACKGROUND

[0002] With the development of new energy industry, lithium ion battery is widely used in life. Lithium ion battery can be divided into laminated and wound type according to the manufacturing method of electrode assembly, laminated battery includes laminated soft package battery and laminated square shell battery, laminated battery is widely used in power battery and 3C battery field due to high volume utilization, fast heat dissipation and other characteristics. SUMMARY

[0003] In view of the problems in the related art, the utility model aims to provide a kind of secondary batteries, battery pack and electronic device, to at least guarantee that adhesive tape is fixed to laminated body.

[0004] To achieve the above object, the utility model provides a kind of secondary batteries, comprising: by positive pole piece, diaphragm, negative pole piece sequentially laminated laminated body, the length direction of the laminated body is the direction of the positive pole piece, the negative pole piece lead-out tab;The laminated body has two narrow sides in width direction, respectively adhered with adhesive tape on the two narrow sides, the laminated body has two big faces in thickness direction, each adhesive tape has two extension parts respectively extended to the two big faces, the size of each extension part meets 2x*d*z / y>1, the x is the adhesive force of the adhesive tape and the diaphragm, the unit of the x is N / m, the d is the size of the adhesive tape along the length direction, the unit of the d is mm, the y is the thickness of the laminated body, the unit of the y is mm, the z is the size of the extension part along the width direction, the unit of the z is mm.

[0005] In some embodiments, the secondary battery is a soft package battery, the soft package battery further comprises: a packaging film encapsulating the laminated body adhered by the adhesive tape, the packaging film has a sealing edge for sealing the laminated body, the sealing edge is at least one side of the laminated body along the width direction, wherein the adhesive tape is located between the narrow side and the sealing edge.

[0006] In some embodiments, the size of each extension part meets 5>2x*d*z / y>1.

[0007] In some embodiments, the range of the d is 5mm to 20mm, the range of the x is 1N / m to 3N / m, the range of the y is 6mm to 14mm, and the range of the z is 5mm to 20mm.

[0008] In some embodiments, along the length direction, the positive electrode tab of the positive electrode tab sheet and the negative electrode tab of the negative electrode tab sheet are located at two ends of the stack body, wherein, along the length direction, the distance between the tape closest to the positive electrode tab on each narrow side and the positive electrode tab ranges from 5mm to 15mm, and the distance between the tape closest to the negative electrode tab on each narrow side and the negative electrode tab ranges from 5mm to 15mm.

[0009] In some embodiments, along the length direction, the positive electrode tab of the positive electrode tab sheet and the negative electrode tab of the negative electrode tab sheet are located at two ends of the stack body, the separator extends from the starting end to the ending end, the separator is alternately stacked between the two narrow sides to form spaces for alternately accommodating the negative electrode tab and the positive electrode tab, and the starting end and the ending end are bound by the tape located on the same narrow side, wherein the distance between the tape closest to the positive electrode tab on the same narrow side and the positive electrode tab ranges from 5mm to 15mm, and the distance between the tape closest to the negative electrode tab on the same narrow side and the negative electrode tab ranges from 5mm to 15mm.

[0010] In some embodiments, the thickness of the tape ranges from 20μm to 50μm, the tape comprises a substrate layer and a bonding layer, the bonding layer bonds the substrate layer and the stack body, and the thickness ratio of the substrate layer and the bonding layer ranges from 1:1 to 1:4.

[0011] Embodiments of the present application also provide a battery pack comprising a plurality of the above secondary batteries stacked along the thickness direction.

[0012] In some embodiments, when the secondary battery is a soft pack battery, the tapes of adjacent secondary batteries are staggered in projection along the thickness direction.

[0013] Embodiments of the present application also provide an electronic device comprising the above battery pack.

[0014] The beneficial technical effects of the present application are as follows:

[0015] The size of the extension part of the tape extending to the large face of the stack body in embodiments of the present application meets the condition 2x*d*z / y>1, the bonding force x between the separator and the tape is calculated, the thickness y of the stack body and the width d of the tape itself are combined, the extension length of the tape on both sides of the stack body is optimized, the tape is prevented from falling off the stack body, the fixing force of the tape on the stack body is ensured throughout the life cycle of the secondary battery, the function of the tape in fixing the positive electrode tab and the negative electrode tab is ensured, and the situation that the stack body is misaligned, the positive electrode tab and / or the negative electrode tab is deviated, and the positive and negative electrodes are overlapped during transportation, thereby causing a safety risk, is avoided. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A schematic diagram is shown when the electronic device according to an embodiment of this application is a vehicle.

[0018] Figure 2 A schematic diagram of an electrode assembly according to some embodiments of this application is shown.

[0019] Figure 3 It shows along Figure 2 The cross-sectional view taken from line AA.

[0020] Figure 4 It shows along Figure 2 A cross-sectional view taken from the BB line.

[0021] Figure 5 A cross-sectional view of a secondary battery obtained by encapsulating an electrode assembly using a packaging film is shown. Detailed Implementation

[0022] To better understand the spirit of the embodiments of this application, the following description is based on some preferred embodiments of this application.

[0023] Embodiments of this application will be described in detail below. Throughout this specification, identical or similar components and components having identical or similar functions are indicated by similar reference numerals. The embodiments described herein with reference to the accompanying drawings are illustrative and diagrammatic in nature and are intended to provide a basic understanding of this application. The embodiments of this application should not be construed as limiting this application.

[0024] As used herein, the terms “approximately,” “generally,” “substantially,” and “about” are used to describe and indicate minor variations. When used in conjunction with an event or situation, these terms may refer to examples in which the event or situation occurred precisely or in examples in which the event or situation occurred very approximately.

[0025] In this description, relative terms such as "central," "longitudinal," "lateral," "forward," "rearward," "rightward," "leftward," "internal," "external," "lower," "higher," "horizontal," "vertical," "above," "below," "top," "bottom," and derivatives thereof (e.g., "horizontally," "downwardly," "upwardly," etc.) should be construed to refer to the orientation as then described or as shown in the drawing under discussion. These relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientations depicted in the figures. The devices can be otherwise oriented (rotated 90 degrees or at other orientations) and the embodiments of the disclosure will operate correctly.

[0026] For the sake of description, "first", "second", "third", etc. can be used herein to distinguish different components of one figure or a series of figures. "First", "second", "third", etc. are not intended to describe the corresponding components.

[0027] The laminated battery uses a laminating machine to stack the positive electrode sheet, the negative electrode sheet, and the separator together. During the stacking process, the negative electrode is required to cover the positive electrode, and the separator is required to cover the negative electrode, and the covering distance has certain limitations, neither too large nor too small, to ensure to improve the volume utilization rate as much as possible, while avoiding the short circuit caused by the overlap of positive and negative electrodes. The electrode assembly (JR) after lamination needs to be fixed on both sides with adhesive tape to prevent the electrode sheet from deviating during the transportation process, which may cause the positive and negative electrodes to overlap. The adhesive tape attached to both sides of the electrode assembly needs to be controlled at an appropriate length (for example, according to the empirical value, the length of the adhesive tape extending to the large face of the electrode assembly in the thickness direction is 3mm to 10mm), too long will cause material waste; too short will cause poor adhesion of the adhesive tape, which cannot play a fixing role, and as the thickness of the electrode assembly becomes thicker, the length of the adhesive tape extending to the large face is insufficient, which often leads to the adhesive tape being detached from the electrode assembly due to insufficient adhesion, especially for soft-pack batteries, the adhesive tape detached from the electrode assembly may be sucked up in the subsequent vacuumizing process, fall into the sealing area of the aluminum plastic film, and be sealed into the seal of the aluminum plastic film in the heat sealing process

the polypropylene (PP) layer of the aluminum plastic film is melted and connected together by heating the sealing head

[0028] The utility model provides a kind of electronic device 1000, the following embodiment is for the convenience of explanation, with electronic device 1000 as vehicle for example is explained. Figure 1The schematic diagram of the electronic device 1000 according to the embodiments of the present application is shown when the electronic device 1000 is a vehicle. The vehicle is internally provided with a battery pack 1002, which can be arranged 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 the operating power supply of the vehicle. The working part of the electronic device 1000 is electrically connected to the battery pack 1002 to obtain power support. The vehicle can be a fuel automobile, a gas automobile or a new energy automobile, and the new energy automobile can be a pure electric automobile, a hybrid electric automobile or a range extended automobile, but is not limited thereto. The battery pack 1002 provides power support for the running of the vehicle or the operation of the electrical elements in the vehicle. However, in some other embodiments, the electronic device 1000 can also be a mobile phone, a portable device, a notebook computer, a ship, a spacecraft, an electric toy and an electric tool, etc. The spacecraft includes an airplane, a rocket, a space shuttle and a spacecraft, etc. The working part is a unit component that can obtain the power of the battery pack 1002 and make corresponding work, for example, a fan blade rotating unit, a dust suction working unit of a dust collector, etc. The electric toy includes a fixed or mobile electric toy, for example, a game console, an electric automobile toy, an electric ship toy and an electric airplane toy, etc. The electric tool includes a metal cutting electric tool, a grinding electric tool, an assembling electric tool and a railway electric tool, for example, an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact electric drill, a concrete vibrator and an electric planer, etc. The embodiments of the present application do not specially limit the above-mentioned electronic device 1000.

[0029] Figure 2 A schematic diagram of the electrode assembly 40 according to some embodiments of the present application is shown. Figure 3 A cross-sectional view taken along the A-A line of Figure 2 is shown. Figure 4 A cross-sectional view taken along the B-B line of Figure 2 is shown. Figure 5 A cross-sectional view of the secondary battery 100 obtained by packaging the electrode assembly 40 using the packaging film 50 is shown, and the position taken is consistent with the B-B line of Figure 2 .

[0030] The embodiments of the present application include a secondary battery 100, which includes a laminated body (electrode assembly) 40 formed by sequentially stacking a positive electrode sheet 10, a separator 20 and a negative electrode sheet 30. As shown in Figure 3 to Figure 5As shown, the separator 20 continuously extends from the starting end 22 to the ending end 24. The separator 20 is first laid from the starting end 22, the negative electrode tab 30 is placed on the separator 20, the separator 20 is pulled from the left side to the right side, the positive electrode tab 10 is placed on the separator 20, then the separator 20 is pulled from the right side to the left side, and the above steps are repeated until the ending end 24 of the separator 20. That is, the separator 20 extends back and forth between the two narrow sides 42 to form spaces 26 alternately accommodating the negative electrode tab 30 and the positive electrode tab 10.

[0031] The positive electrode tab 10 and the negative electrode tab 30 are led out along the length direction L of the stack 40, the stack 40 has two opposite narrow sides 42 in the width direction W, a plurality of tapes 50 are respectively adhered to the two narrow sides 42 and spaced apart along the length direction L, and the stack 40 has two opposite large faces 44 in the thickness direction T. Each tape 50 extends to the two large faces 44 to bind the stack 40. The size of each of the two extension portions 52 of the tape respectively extending to the two large faces 44 meets 2x*d*z / y>1, x is the adhesion (peeling force) between the tape 50 and the separator 20, x is in N / m, see Figure 2 , d is the size of the tape 50 along the length direction L, d is in mm, see Figure 3 , y is the thickness of the stack 40, y is in mm, see Figure 2 , and z is the size of the extension portion 52 along the width direction W, z is in mm. The size of the tape 50 or the adhesion x is adjusted according to the change of the thickness of the stack 40, for example, the thickness of the stack 40 is getting larger and larger at present, so the area of the extension portion 52 of the tape 50 extending to the large face 44 is increased, or the adhesion x between the tape 50 and the separator 20 is increased, to ensure the good adhesion between the tape 50 and the stack 40. The size of the extension portion 52 of the tape 50 of the embodiment of the application extending to the large face 44 of the stack 40 meets 2x*d*z / y>1, by measuring the adhesion x between the separator 20 and the tape 50, combining the thickness y of the stack 40 and the width d of the tape 50 itself, the extension length of the tape 50 on both sides of the stack 40 (the thickness y of the stack 40 plus the size z of the two extension portions 52) is optimized, to prevent the tape 50 from falling off the stack 40, ensure the fixing force of the tape 50 on the stack 40 throughout the life cycle of the secondary battery 100, ensure that the tape 50 plays a role in fixing the positive electrode tab 10 and the negative electrode tab 30, and avoid the mispositioning of the stack 40 and the deviation of the positive electrode tab 10 and / or the negative electrode tab 30 during the transportation process, which may cause the positive and negative electrodes to be overlapped and cause a safety risk.

[0032] The secondary battery 100 is a soft package battery or a square can battery. In the embodiment in which the secondary battery 100 is a soft package battery, see Figure 5The secondary battery 100 further includes a packaging film 60 encapsulating the jelly-roll 40 adhered by the adhesive tape 50, the packaging film 60 is, for example, an aluminum-plastic film, the packaging film 60 has a sealing edge 62 for sealing the jelly-roll 40, the sealing edge 62 is at least one side of the jelly-roll 40 along the width direction W, wherein the adhesive tape 50 is located between the narrow side 42 and the sealing edge 62. For the embodiment of the secondary battery 100 as a soft-pack battery, if the adhesive tape 50 is not well pasted, the part of the adhesive tape 50 that is lifted off the jelly-roll 40 is easy to enter the sealing edge 62 of the packaging film 60, resulting in a failure of heat sealing and causing a leakage, the embodiment of the application controls the size of the adhesive tape 50 to prevent the adhesive tape 50 from being lifted off the jelly-roll 40, avoiding the lifted adhesive tape 50 from entering the sealing edge 62, affecting the sealing of the secondary battery 100, causing a leakage and failure, and causing a safety accident.

[0033] Further, the size of each extension 52 meets 5>2x*d*z / y>1, d is the width of the adhesive tape 50 itself, for example, in the range of 5mm to 20mm, avoiding too large width to increase the risk of wrinkles when the adhesive tape 50 is bonded, and avoiding too small width to reduce the bonding strength and the connecting strength; x is in the range of 1N / m to 3N / m; y is in the range of 6mm to 14mm; z is in the range of 5mm to 20mm. While ensuring that the adhesive tape 50 plays a role in fixing the jelly-roll 40, 2x*d*z / y<5 makes the use of the adhesive tape 50 the least, reduces material consumption, and avoids waste. In the embodiment of the secondary battery 100 as a soft-pack battery, the battery pack 1002 includes a plurality of secondary batteries 100 stacked along the thickness direction T, and the plurality of secondary batteries 100 are closely pasted, the embodiment of the application ensures the fixing effect of the adhesive tape 50 on the jelly-roll 40 while reducing the size of the extension 52 of the adhesive tape 50 on the large face 44 of the jelly-roll 40 as much as possible, to avoid the thickness accumulation at the adhesive tape 50 of the plurality of secondary batteries 100 increasing, causing a larger pressure on the large face 44 of the jelly-roll 40 to increase the unevenness of the pressure, affecting the flatness of the large face 44, and further affecting the cycle life of the secondary battery 100. In addition, when the secondary battery 100 is a soft-pack battery, the projections of the adhesive tapes 50 of adjacent secondary batteries 100 in the battery pack 1002 along the thickness direction T are staggered, to avoid the thickness accumulation at the adhesive tape 50 increasing.

[0034] Referring to Figure 2Along the length direction L, the positive electrode tab 12 of the positive electrode 10 and the negative electrode tab 32 of the negative electrode 30 are located at both ends of the stacked body 40, and the positive electrode tab 12 and the negative electrode tab 32 will not contact each other to avoid short circuit. Along the length direction L, the distance e between the tape 50 closest to the positive electrode tab 12 on each narrow side 42 and the positive electrode tab 12 ranges from 5mm to 15mm, and the distance c between the tape 50 closest to the negative electrode tab 32 on each narrow side ranges from 5mm to 15mm. That is, the size of the part of the stacked body 40 not bound by the tape 50 is limited to the range of 5mm to 15mm, ensuring the fixing effect of the tape 50 on the stacked body 40. Figure 3 to Figure 5 In the embodiment shown, the starting end 22 and the ending end 24 of the diaphragm 50 are located on the same narrow side 42. Figure 3 to Figure 5 The tape 50 on the narrow side 42 on the right side of the middle electrode is bound together, and the distance e between the tape 50 closest to the positive electrode tab 12 on the same narrow side 42 and the positive electrode tab 12 is in the range of 5mm to 15mm. The distance c between the tape 50 closest to the negative electrode tab 32 on the same narrow side 42 and the negative electrode tab 32 is in the range of 5mm to 15mm. The adhesion between the separator 20 and the positive electrode 10 and the negative electrode 20 is limited. In the embodiments of this application, the distance e and c between the tape 50 binding the starting end 22 and the ending end 24 of the separator 20 and the two ends of the stacked body 40 are limited to avoid the problem of black leakage (the black active material layer of the negative electrode 30 being exposed) caused by the corners of the starting end 22 and the ending end 24 of the separator 20 being folded at the two ends of the stacked body 40. The ending end 24 of the separator 20 in the embodiments of this application is not limited to Figure 3 to Figure 5 At the position shown, the diaphragm 20 can extend almost another full circle around the stacked sheet 40 to cover the opening of the space 26.

[0035] In some embodiments, the thickness of the tape 50 ranges from 20 μm to 50 μm. The tape 50 includes a substrate layer and an adhesive layer, the adhesive layer bonding the substrate layer and the laminate 40. The thickness ratio of the substrate layer to the adhesive layer ranges from 1:1 to 1:4. The substrate layer is made of materials such as polyethylene terephthalate (PET) or oxidized polyethylene wax (OPE), and the adhesive layer is made of materials such as acrylic, rubber, or silicone. If the tape 50 is too thick, it will be too stiff and difficult to bend, resulting in the extension 52 not adhering to the laminate 50. If the tape 50 is too thin, the adhesive layer will be insufficient, making it difficult to meet the requirement of adhesive strength x. In addition, the substrate layer cannot be too thin to ensure the strength of the tape 50; if the substrate layer is too thick, the tape 50 will be too stiff and difficult to adhere.

[0036] The above merely describes preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A secondary battery characterized by comprising: The secondary battery comprises: a stack body formed by stacking a positive electrode sheet, a separator, and a negative electrode sheet in this order, the length direction of the stack body being the direction in which tabs of the positive electrode sheet and the negative electrode sheet are drawn out; the stack body having two opposite narrow sides in the width direction, and adhesive tapes being adhered to the two narrow sides, respectively, the stack body having two opposite large faces in the thickness direction, each of the adhesive tapes having two extension portions extending onto the two large faces, respectively, each of the extension portions satisfying the condition 2x*d*z / y>1, x being the adhesive force between the adhesive tape and the separator, x being in units of N / m, d being the size of the adhesive tape in the length direction, d being in units of mm, y being the thickness of the stack body, y being in units of mm, and z being the size of the extension portion in the width direction, z being in units of mm.

2. The secondary battery according to claim 1, characterized by The secondary battery is a soft-packaged battery, and the soft-packaged battery further comprises: a packaging film encapsulating the stack body adhered by the adhesive tapes, the packaging film having a sealing edge for sealing the stack body, the sealing edge being on at least one side of the stack body in the width direction, wherein the adhesive tapes are located between the narrow sides and the sealing edge.

3. The secondary battery according to claim 1 or 2, characterized by Each of the extension portions satisfies the condition 5>2x*d*z / y>1.

4. The secondary battery according to claim 3, characterized by d is in the range of 5 mm to 20 mm, x is in the range of 1 N / m to 3 N / m, y is in the range of 6 mm to 14 mm, and z is in the range of 5 mm to 20 mm.

5. The secondary battery according to claim 1 or 2, characterized by In the length direction, the positive electrode tabs of the positive electrode sheet and the negative electrode tabs of the negative electrode sheet are located at both ends of the stack body, wherein, in the length direction, the distance between the adhesive tape closest to the positive electrode tab on each of the narrow sides and the positive electrode tab is in the range of 5 mm to 15 mm, and the distance between the adhesive tape closest to the negative electrode tab on each of the narrow sides and the negative electrode tab is in the range of 5 mm to 15 mm.

6. The secondary battery according to claim 1 or 2, characterized by In the length direction, the positive electrode tabs of the positive electrode sheet and the negative electrode tabs of the negative electrode sheet are located at both ends of the stack body, the separator extending from a starting end to an ending end, the separator being alternately stacked between the two narrow sides to form spaces for accommodating the negative electrode sheet and the positive electrode sheet, the starting end and the ending end being bound by the adhesive tapes located on the same narrow side, wherein the distance between the adhesive tape closest to the positive electrode tab on the same narrow side and the positive electrode tab is in the range of 5 mm to 15 mm, and the distance between the adhesive tape closest to the negative electrode tab on the same narrow side and the negative electrode tab is in the range of 5 mm to 15 mm.

7. The secondary battery according to claim 1 or 2, characterized by The thickness of the adhesive tape is in the range of 20 μm to 50 μm, the adhesive tape comprises a substrate layer and an adhesive layer, the adhesive layer binding the substrate layer and the stack body, and the thickness ratio of the substrate layer to the adhesive layer is in the range of 1:1 to 1:

4.

8. A battery pack characterized by comprising: The secondary battery comprises: a plurality of the secondary batteries according to any one of claims 1 to 7 stacked in the thickness direction.

9. The battery pack of claim 8, wherein, When the secondary battery is a soft-pack battery, the tapes of adjacent secondary batteries are offset in the thickness direction.

10. An electronic device, comprising: A battery pack comprising the battery of claim 8 or 9.

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