Soft package battery

Abstract

The utility model provides a soft package battery which comprises a packaging film, air holes are formed in the packaging film, the soft package battery further comprises an air-permeable film, the air holes are sealed by the air-permeable film, and the air-permeable film can block liquid and permeate gas. Gas in the soft package battery can be discharged through the gas-permeable membrane, so that the safety performance and the service life of the battery are improved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a soft-pack battery. Background Art

[0002] In recent decades, the technology of lithium-ion batteries has developed rapidly, and its application in digital products, power tools and electric vehicles has become more and more extensive. As the energy density of lithium-ion batteries continues to increase, people are increasingly concerned about their safety performance. Lithium-ion batteries are divided into square lithium batteries, cylindrical lithium batteries and button lithium batteries according to their appearance, and are divided into aluminum shell lithium batteries, steel shell lithium batteries and soft pack batteries according to their packaging materials. Among them, soft pack batteries have higher single energy density and better safety performance. Soft pack batteries are generally packaged with aluminum plastic film.

[0003] High-nickel ternary materials, high-voltage ternary materials, natural graphite, silicon-based negative electrodes and other materials in lithium-ion batteries are easy to oxidize or reduce the electrolyte during the cycle process, causing gas production in the battery cells. When the gas production is severe, the battery cells will be deformed, affecting performance, and even bursting the aluminum-plastic film, causing electrolyte leakage and posing a safety hazard.

[0004] The prior art generally uses devices such as conduits and exhaust pipes to discharge the gas in the battery to improve the safety performance of the battery cell. However, this type of exhaust device has the following problems when used: 1. Since it is difficult for this type of exhaust device to be in close contact with the aluminum-plastic film, it is easy to cause packaging problems (i.e., it cannot be completely sealed); 2. The rubber plug materials used in the conduit and exhaust pipe are easy to age and have a limited service life. They may not work after long-term use; 3. This type of exhaust device has a certain weight. Installing this type of exhaust device on the battery will cause the energy density of the battery cell to drop significantly. Utility Model Content

[0005] The purpose of the present application is to provide a soft-pack battery, aiming to solve the deficiencies of the above-mentioned background technology. The gas in the soft-pack battery can be discharged through the breathable membrane, thereby improving the safety performance and service life of the battery.

[0006] An embodiment of the present application provides a soft-pack battery, including a packaging film, wherein the packaging film is provided with at least one air hole, and the soft-pack battery also includes a breathable film, wherein the breathable film is fitted and connected to the packaging film at a position corresponding to the air hole, the breathable film seals the air hole, and the breathable film can block liquid and pass gas.

[0007] Thus, the breathable film can block liquid and pass gas, so the electrolyte in the packaging film cannot leak from the breathable film. At the same time, since gas is continuously generated in the soft-pack battery, the air pressure in the soft-pack battery is generally higher than the external air pressure. Under the effect of the pressure difference between the inside and outside of the soft-pack battery, the gas in the soft-pack battery can be discharged through the breathable film, and the external gas will not enter the soft-pack battery through the breathable film.

[0008] In one achievable manner, at least one side of the soft-pack battery is provided with a pole ear, the packaging film is provided with a top sealing area at a position corresponding to the pole ear, and the vent hole is arranged in the top sealing area.

[0009] Therefore, when gas is generated in the soft-pack battery, the gas pressure is higher than the external air pressure, and the soft-pack battery is relatively weak at the pole ear, and the gas is easy to rush out from the pole ear. Therefore, the air vent is provided in the top sealing area at the pole ear, which can better achieve the exhaust effect and improve the battery safety.

[0010] In one achievable manner, the tab is disposed on one side of the soft-pack battery.

[0011] In an achievable manner, the tab is disposed on one side of the soft-pack battery along the width direction of the soft-pack battery, the top seal region is disposed on one side of the packaging film close to the tab, the top seal region is extended along the length direction of the soft-pack battery, and the number of the vent holes is one or more. When the number of the vent holes is multiple, the multiple vent holes can be arranged along the length direction of the soft-pack battery.

[0012] Therefore, when the top sealing area is located on one side in the width direction of the soft-pack battery, one or more vents arranged along the length direction of the soft-pack battery are arranged in the top sealing area extending along the length direction of the soft-pack battery, thereby maximizing the use of the area of ​​the top sealing area and providing a better exhaust effect.

[0013] In one achievable manner, the tabs are arranged on opposite sides of the soft-pack battery, the top seal area is arranged on opposite sides of the packaging film, and the vent holes are arranged in the top seal area on at least one side of the packaging film.

[0014] In an achievable manner, the tabs are arranged on opposite sides of the soft-pack battery along the length direction of the soft-pack battery, the top seal area is arranged on opposite sides of the packaging film along the length direction of the soft-pack battery, the top seal area is extended along the width direction of the soft-pack battery, and the number of the air holes is one or more. When the number of the air holes is multiple, the multiple air holes can be arranged in an array along the width direction of the soft-pack battery.

[0015] Therefore, when the top sealing area is located on opposite sides of the length direction of the soft-pack battery, one or more ventilation holes arranged along the width direction of the soft-pack battery are arranged in the top sealing area extending along the width direction of the soft-pack battery, thereby maximizing the use of the area of ​​the top sealing area on both sides and providing a better exhaust effect.

[0016] In one feasible manner, the soft-pack battery also includes a battery cell, which is arranged in the packaging film, one end of the pole ear is connected to the battery cell, the pole ear glue is provided on the pole ear, the pole ear glue is located in the top seal area, and the air vent is located between the pole ear glue and the battery cell.

[0017] Therefore, the tab glue can not only prevent the packaging film from contacting the tab and causing a short circuit, but also prevent the electrolyte inside the battery from leaking. Since the packaging position of the tab and the packaging film corresponds to the position of the tab glue, and the vent is located between the tab glue and the battery cell, the vent position is not sealed, so that the gas in the packaging film can be smoothly discharged through the vent.

[0018] In an achievable manner, the air holes occupy 1%-80%, or 5%-60%, or 10%-40% of the area of ​​the top sealing region.

[0019] In an achievable manner, the soft-pack battery is provided with a tab, the tab is arranged on one side of the soft-pack battery along the width direction of the soft-pack battery, the vent holes are arranged on one side or two opposite sides of the packaging film along the length direction of the soft-pack battery, and the number of the vent holes on each side is one or more. When the number of the vent holes on each side is multiple, the multiple vent holes on each side can be arranged in an array along the width direction of the soft-pack battery.

[0020] In an achievable manner, the soft-pack battery is provided with tabs, which are arranged on two opposite sides of the soft-pack battery along the length direction of the soft-pack battery, and the vent holes are arranged on one side or two opposite sides of the packaging film along the width direction of the soft-pack battery, and the number of the vent holes on each side is one or more. When the number of the vent holes on each side is multiple, the multiple vent holes on each side can be arranged in an array along the length direction of the soft-pack battery.

[0021] In one achievable manner, the area of ​​the vent hole is 0.0001-900 mm 2 , or 0.01-9mm 2 .

[0022] In one achievable manner, the breathable film and the packaging film are fixed by bonding; or the breathable film and the inner surface and / or outer surface of the packaging film are fixed by bonding.

[0023] In one achievable manner, the gas that the breathable membrane can pass through includes CO 2 ,CO,N 2 , CH 4 , C 2 H 4 , C 2 H 2 and O 2 .

[0024] The soft-pack battery provided by the present application is provided with air holes on the packaging film and air-permeable membrane at the air holes. The air-permeable membrane can block liquid and pass gas. When gas is generated in the soft-pack battery and reaches a certain pressure, the gas can be discharged to the outside of the soft-pack battery through the air-permeable membrane, thereby avoiding deformation of the battery cell or rupture of the packaging film due to excessive internal pressure. The battery can continue to be used after exhausting, which improves the safety performance and service life of the battery. At the same time, the packaging process of this structure is simple, the strength is high, the service life is long, and the mass of the air-permeable membrane is small, which does not affect the energy density of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a cross-sectional schematic diagram of the soft-pack battery in the first embodiment of the present application.

[0026] Figure 2 It is a cross-sectional schematic diagram of the soft-pack battery in the second embodiment of the present application.

[0027] Figure 3 It is a cross-sectional schematic diagram of the soft-pack battery in the third embodiment of the present application.

[0028] Figure 4 It is a cross-sectional schematic diagram of the soft-pack battery in the fourth embodiment of the present application.

[0029] Figure 5 It is a cross-sectional schematic diagram of the soft-pack battery in the fifth embodiment of the present application.

[0030] Figure 6 It is a cross-sectional schematic diagram of the soft-pack battery in the sixth embodiment of the present application. DETAILED DESCRIPTION

[0031] The specific implementation methods of the present application are further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present application but are not intended to limit the scope of the present application.

[0032] The terms "first", "second", "third", "fourth" and the like (if any) in the description and claims of the present application are used to distinguish similar objects and not necessarily to describe a particular sequence or order.

[0033] like Figure 1 As shown, the embodiment of the present application provides a soft-pack battery, including a packaging film 1, and the packaging film 1 is provided with a vent hole 11. The soft-pack battery also includes a vent film 2, and the vent film 2 is attached to the packaging film 1 at a position corresponding to the vent hole 11, and the vent film 2 seals the vent hole 11, and the vent film 2 can block liquid and pass gas.

[0034] As an embodiment, the packaging film 1 is an aluminum-plastic film.

[0035] like Figure 1 As shown, as an embodiment, a pole ear 3 is provided on at least one side of the soft-pack battery, a top sealing area 12 (i.e., the area where the packaging film 1 is packaged) is provided on the packaging film 1 at a position corresponding to the pole ear 3, and a vent hole 11 is arranged in the top sealing area 12.

[0036] like Figure 1 As shown, as an embodiment, the soft-pack battery further includes a battery cell 5, which is encapsulated in a packaging film 1, one end of the tab 3 is connected to the battery cell 5, and the other end of the tab 3 is exposed outside the packaging film 1. An electrolyte is provided in the packaging film 1, and the battery cell 5 is immersed in the electrolyte.

[0037] Specifically, since the breathable film 2 can block liquid and pass gas, the electrolyte in the packaging film 1 cannot leak from the breathable film 2. At the same time, since gas is continuously generated in the soft-pack battery, the air pressure in the soft-pack battery is generally higher than the external air pressure. Under the effect of the pressure difference between the inside and outside of the soft-pack battery, the gas in the soft-pack battery can be discharged through the breathable film 2, and the external gas will not pass through the breathable film 2 into the soft-pack battery.

[0038] like Figure 1 As shown, as an implementation mode, when the soft-pack battery adopts a structure with a single-sided tab 3, the tab 3 is arranged on one side of the soft-pack battery.

[0039] like Figure 1 As shown, as an embodiment, the tab 3 is arranged on one side of the soft-pack battery along the width direction W of the soft-pack battery, the top sealing area 12 is arranged on the side of the packaging film 1 close to the tab 3, the top sealing area 12 extends along the length direction L of the soft-pack battery, the number of the vents 11 is multiple, the multiple vents 11 are arranged along the length direction L of the soft-pack battery, and the multiple vents 11 are arranged in a row along the length direction L of the soft-pack battery. Of course, as Figure 3As shown, in other embodiments, the plurality of vent holes 11 may also be arranged in two or more rows along the length direction L of the soft-pack battery. Alternatively, the plurality of vent holes 11 may not be arranged linearly.

[0040] like Figure 4 As shown, as another embodiment, the vent holes 11 may not be arranged in the top seal area 12. Specifically, the soft-pack battery is provided with a pole ear 3, which is arranged on one side of the soft-pack battery along the width direction W of the soft-pack battery, and the vent holes 11 are arranged on one side or two opposite sides of the packaging film 1 along the length direction L of the soft-pack battery. The number of vent holes 11 on each side is multiple, and the multiple vent holes 11 on each side are arranged along the width direction W of the soft-pack battery. Of course, in other embodiments, the multiple vent holes 11 may also be arranged in a W shape, an L shape, etc., or in an irregular arrangement.

[0041] like Figure 1 As shown, as an implementation mode, the number of the pole tabs 3 is two, and the two pole tabs 3 are respectively a positive pole tab and a negative pole tab, and the positive and negative pole tabs are respectively connected to the positive and negative poles of the battery cell 5 .

[0042] like Figure 2 As shown, as another embodiment, when the soft-pack battery adopts a double-sided electrode tab 3 structure, the electrode tab 3 is arranged on opposite sides of the soft-pack battery, the top sealing area 12 is arranged on opposite sides of the packaging film 1, and the air vent 11 is arranged in the top sealing area 12 on at least one side of the packaging film 1.

[0043] like Figure 2 As shown, as another embodiment, the tabs 3 are arranged on opposite sides of the soft-pack battery along the length direction L of the soft-pack battery, the top sealing area 12 is arranged on opposite sides of the packaging film 1 along the length direction L of the soft-pack battery, the top sealing area 12 extends along the width direction W of the soft-pack battery, the number of the vents 11 is multiple, the multiple vents 11 are arranged along the width direction W of the soft-pack battery, and the multiple vents 11 on each side are arranged in a row along the width direction W of the soft-pack battery. Of course, as Figure 5 As shown, in other embodiments, the plurality of vent holes 11 on each side may also be arranged in two or more rows along the width direction W of the soft-pack battery. Alternatively, the plurality of vent holes 11 may not be arranged linearly.

[0044] like Figure 6As shown, as another embodiment, the vent holes 11 may not be arranged in the top seal area 12. Specifically, the soft-pack battery is provided with tabs 3, which are arranged on opposite sides of the soft-pack battery along the length direction L of the soft-pack battery, and the vent holes 11 are arranged on one side or opposite sides of the packaging film 1 along the width direction W of the soft-pack battery. The number of vent holes 11 on each side is multiple, and the multiple vent holes 11 on each side are arranged along the length direction L of the soft-pack battery. Of course, in other embodiments, the multiple vent holes 11 may also be arranged in a W shape, an L shape, etc., or in an irregular arrangement.

[0045] like Figure 1 As shown, as an implementation mode, a tab glue 4 is provided on the tab 3 , the tab glue 4 is located in the top sealing area 12 , and the vent hole 11 is located between the tab glue 4 and the battery cell 5 .

[0046] Specifically, the tab glue 4 is used for hot-melt sealing between the packaging film 1 and the tab 3. During the packaging process of the soft-pack battery, the position between the tab 3 and the packaging film 1 corresponding to the tab glue 4 is heat-sealed, that is, the packaging position of the tab 3 and the packaging film 1 corresponds to the position of the tab glue 4, so that the tab glue 4 is heated and melted to achieve the connection between the tab 3 and the packaging film 1. Since the packaging position of the tab 3 and the packaging film 1 corresponds to the position of the tab glue 4, and the vent 11 is located between the tab glue 4 and the battery cell 5, the vent 11 is not sealed, so that the gas in the packaging film 1 can be discharged smoothly through the vent 11.

[0047] As an implementation manner, the air holes 11 occupy 1%-80% of the area of ​​the top sealing region 12 .

[0048] As another embodiment, the air holes 11 occupy 5%-60% of the area of ​​the top sealing region 12 .

[0049] As another embodiment, the air holes 11 occupy 10%-40% of the area of ​​the top sealing region 12 .

[0050] As an embodiment, the area of ​​the vent hole 11 is 0.0001-900mm 2 .

[0051] As another embodiment, the area of ​​the air vent 11 is 0.01-9 mm 2 .

[0052] As an implementation manner, the shape of the air vent 11 can be a regular shape such as a circle, an ellipse, a square, a rectangle, a diamond, etc., and of course can also be other irregular shapes, which are not limited here.

[0053] As an embodiment, the breathable film 2 and the packaging film 1 are fixed by bonding, and the breathable film 2 can be attached to the inner surface of the packaging film 1, or to the outer surface of the packaging film 1, or to both the inner surface and the outer surface of the packaging film 1. The bonding method of the breathable film 2 and the packaging film 1 can be adhesive bonding, hot pressing bonding, or hot melt bonding. Preferably, the breathable film 2 and the packaging film 1 can be bonded by an adhesive or hot pressing bonding.

[0054] As an embodiment, the gas that the breathable membrane 2 can pass through includes CO 2 ,CO,N 2 , CH 4 , C 2 H 4 , C 2 H 2 and O 2 .

[0055] As an embodiment, the material of the breathable membrane 2 includes but is not limited to polysulfones and their derivatives, fluorine-containing polymers, polyphenylene ethers and their derivatives, polydimethylsiloxanes and their derivatives, polyamides or polyimides and their derivatives, polyurethanes or polyesters and their derivatives, polyolefins and their derivatives, etc. Preferably, the material of the breathable membrane 2 may be a polyolefin derivative, such as polyacrylonitrile; or a fluorine-containing polymer, such as polytetrafluoroethylene; or polydimethylsiloxanes and their derivatives, such as polydimethylsiloxane. The material of the breathable membrane 2 may also be a mixture of two or more of the above materials, and the mixing method may be direct mixing or multi-layer composite.

[0056] As an embodiment, the relative molecular mass of the material of the breathable membrane 2 is 10 3 -10 8 , the molecular weight distribution index is 1.0-3.0. Preferably, the relative molecular mass of the material of the breathable membrane 2 is 10 5 -10 7 , the molecular weight distribution index is 1.0-1.5.

[0057] The soft-pack battery provided in the embodiment of the present application is provided with a vent hole 11 on the packaging film 1, and a vent film 2 is provided at the vent hole 11. The vent film 2 can block liquid and pass gas. When gas is generated in the soft-pack battery and reaches a certain pressure, the gas can be discharged to the outside of the soft-pack battery through the vent film 2, thereby avoiding deformation of the battery cell 5 or rupture of the packaging film 1 due to excessive internal pressure. The battery can continue to be used after exhausting, which improves the safety performance and service life of the battery. At the same time, compared with other exhaust valve solutions, this structure has a simple packaging process, high strength, and long service life, and the mass of the vent film 2 is small, which does not affect the energy density of the battery.

[0058] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A soft pack battery, comprising a packaging film (1), characterized in that: The packaging film (1) is provided with at least one vent hole (11), the soft-pack battery further comprises a vent film (2), the vent film (2) seals the vent hole (11), and the vent film (2) can block liquid and pass gas; the area of ​​the vent hole (11) is 0.0001-900 mm 2 .

2. The soft pack battery according to claim 1, characterized in that: At least one side of the soft-pack battery is provided with a pole ear (3), the packaging film (1) is provided with a top sealing area (12) at a position corresponding to the pole ear (3), and the vent hole (11) is arranged in the top sealing area (12).

3. The soft pack battery according to claim 2, characterized in that: The tab (3) is arranged on one side of the soft-pack battery.

4. The soft pack battery according to claim 3, characterized in that: The pole lug (3) is arranged on one side of the soft-pack battery along the width direction (W) of the soft-pack battery, the top sealing area (12) is arranged on a side of the packaging film (1) close to the pole lug (3), and the top sealing area (12) is extended along the length direction (L) of the soft-pack battery.

5. The soft pack battery according to claim 2, characterized in that: The tabs (3) are arranged on two opposite sides of the soft-pack battery, and the vent holes (11) are arranged in the top sealing area (12) on at least one side of the packaging film (1).

6. The soft pack battery according to claim 5, characterized in that: The tabs (3) are arranged on opposite sides of the soft-pack battery along the length direction (L) of the soft-pack battery, the top sealing area (12) is arranged on opposite sides of the packaging film (1) along the length direction (L) of the soft-pack battery, the top sealing area (12) is extended along the width direction (W) of the soft-pack battery, and the number of the air holes (11) on each side of the length direction (L) is one or more.

7. The soft pack battery according to claim 2, characterized in that: The soft-pack battery also includes a battery cell (5), wherein the battery cell (5) is arranged in the packaging film (1), one end of the pole ear (3) is connected to the battery cell (5), the pole ear glue (4) is provided on the pole ear (3), the pole ear glue (4) is located in the top sealing area (12), and the air vent (11) is located between the pole ear glue (4) and the battery cell (5).

8. The soft pack battery according to any one of claims 2 to 7, characterized in that: The air holes (11) account for 1% to 80% of the area of ​​the top sealing region (12).

9. The soft pack battery according to claim 1, characterized in that: The soft-pack battery is provided with a pole ear (3), and the pole ear (3) is arranged on one side of the soft-pack battery along the width direction (W) of the soft-pack battery. The air holes (11) are arranged on one side or two opposite sides of the packaging film (1) along the length direction (L) of the soft-pack battery, and the number of the air holes (11) on each side is one or more.

10. The soft pack battery according to claim 1, characterized in that: The soft-pack battery is provided with a pole ear (3), and the pole ear (3) is arranged on two opposite sides of the soft-pack battery along the length direction (L) of the soft-pack battery. The air holes (11) are arranged on one side or two opposite sides of the packaging film (1) along the width direction (W) of the soft-pack battery, and the number of the air holes (11) on each side is one or more.

11. The soft pack battery according to claim 1, characterized in that: The breathable film (2) and the packaging film (1) are fixed by bonding.

Images