Battery cell, electrochemical device, and electric equipment

Abstract

The application provides an electric core, comprising an electrode assembly and a bag containing the electrode assembly, the material of the bag is a multilayer sheet, the multilayer sheet comprises a color developing layer, the color developing layer comprises an adjacent base layer and a dye layer, and the dye layer is configured to dye the base layer when the pressure exceeds a predetermined pressure or the temperature exceeds a predetermined temperature threshold. The above-mentioned electric core can dye the base layer through the dye layer when the pressure or the temperature exceeds the threshold, so that the surface of the base layer appears color difference, and then the pressure and temperature balance of the electric core can be observed and judged without disassembling the electric core, thereby reducing the probability of failure of the electric core caused by uneven pressure and temperature. The application also provides an electrochemical device and an electric equipment with the above-mentioned electric core, and the above-mentioned electrochemical device and electric equipment reduce the probability of failure caused by excessive / unbalanced pressure and temperature of the electric core, and improve the stability.

Description

Technical Field

[0001] This application relates to a battery cell, an electrochemical device, and an electrical device. Background Technology

[0002] Currently, during the battery cell production process, the surface of the battery cell is subjected to high temperature and high pressure during production processes such as formation. Often, due to the parallelism of the battery cell itself or the equipment, the pressure on the battery cell surface during formation is too great, resulting in poor interface bonding. This can lead to problems such as cycle decay and abnormal expansion during battery cell use. However, failure analysis requires disassembling the battery cell to make a judgment, which means that the uniformity of the interface bonding of the battery cell cannot be directly judged at the time of shipment. Summary of the Invention

[0003] In view of this, it is necessary to provide a method that can efficiently determine whether the overall pressure of the battery cell is uneven or exceeds the threshold during formation, so as to prevent battery cells with uneven pressure or exceeding the threshold from entering the market and causing potential failure / safety problems.

[0004] One embodiment of this application provides a battery cell, which includes an electrode assembly and a bag housing the electrode assembly. The bag is made of a multilayer sheet. The multilayer sheet includes a color-developing layer. The color-developing layer includes an adjacent substrate layer and a dye layer. The dye layer is configured to dye the substrate layer when subjected to pressure exceeding a predetermined pressure or temperature exceeding a predetermined temperature threshold.

[0005] The aforementioned battery cell uses a dye layer to color the base layer when subjected to pressure or temperature exceeding a threshold, resulting in color differences on the surface of the base layer. This allows for observation and judgment of whether the battery cell is subjected to pressure or temperature exceeding the threshold and whether the temperature is uniform without disassembling the battery cell, thus reducing the probability of battery cell failure due to excessive or uneven pressure or temperature.

[0006] In some embodiments, the multilayer sheet further includes a first polymer layer, a color-developing layer is adhered to the first polymer layer, and the color-developing layer is the outermost layer of the multilayer sheet.

[0007] Furthermore, the base layer is located between the dye layer and the first polymer layer, or the dye layer is located between the base layer and the first polymer layer.

[0008] In some embodiments, the multilayer sheet further includes a metal layer and a first polymer layer, with the color layer located between the metal layer and the first polymer layer.

[0009] Furthermore, the dye layer is located between the substrate layer and the metal layer, or the substrate layer is located between the dye layer and the metal layer.

[0010] In some embodiments, the multilayer sheet further includes a second polymer layer, the first polymer layer is disposed between the color development layer and the electrode assembly (i.e., the surface of the second polymer layer is opposite to the surface of the electrode assembly), and a metal layer is disposed between the color development layer and the second polymer layer.

[0011] In some embodiments, the multilayer sheet further includes a film layer, which is bonded to the dye layer and is the outermost layer of the multilayer sheet. The dye layer can be peeled off from the base layer along with the film layer.

[0012] Furthermore, the dye layer is located between the substrate layer and the film layer, or the substrate layer is located between the dye layer and the film layer.

[0013] In some embodiments, the first polymer layer may be a polyamide material, such as nylon materials like polybutadiene adipamide / polycaprolactam, or crystalline saturated polyesters (such as polyethylene terephthalate (PET) or polybutylene terephthalate (PBT)).

[0014] In some embodiments, the second polymer layer is an olefin polymer (polypropylene material), such as a polypropylene film (PP, CPP, OPP, MPP) or other olefin polymer layer.

[0015] In some embodiments, the metal layer is an aluminum layer, a stainless steel layer, a composite material (such as an aluminum-plated packaging film), etc.

[0016] In some embodiments, the film layer is a polyester polymer film material, such as polyethylene terephthalate (PET).

[0017] In some embodiments, the dye layer includes a plurality of dye capsules, each dye capsule including a shell and a dye filler, the shell enclosing the dye filler, the shell being configured to rupture and release the dye filler when subjected to a predetermined pressure or a predetermined temperature threshold.

[0018] In some embodiments, the dye layer includes an adhesive for bonding the dye capsules to the substrate layer. The adhesive may be a commonly used acrylic adhesive, epoxy resin adhesive, anaerobic adhesive, UV adhesive (ultraviolet light curing type), hot melt adhesive, pressure sensitive adhesive, or latex adhesive, etc.

[0019] In some embodiments, the dyeing filler includes an acidic substance, and the base layer includes an acid-sensitive color-developing substance.

[0020] Furthermore, in some embodiments, the acidic substance includes at least one of HCl, HBr, HI, HNO3, HF, H2C2O4 or HClO4, and the base layer includes a litmus coating.

[0021] In some embodiments, the dyeing filler includes an alkaline substance, and the base layer includes a substance that develops color upon contact with alkali.

[0022] Furthermore, in some embodiments, the substrate layer includes a phenolphthalein coating.

[0023] In some embodiments, the base layer and the dye layer are bonded together by at least one of adhesive bonding, thermoplastic bonding, or surface spraying.

[0024] In some embodiments, the thickness of the dye layer ranges from 3 μm to 20 μm, and the thickness of the substrate layer ranges from 3 μm to 20 μm.

[0025] One embodiment of this application also provides an electrochemical device, including any of the above-described battery cells.

[0026] One embodiment of this application also provides an electrical device, including the electrochemical device described above.

[0027] The aforementioned electrochemical device and electrical equipment reduce the probability of failure caused by excessive or uneven pressure and temperature on the battery cells, thus improving stability. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the battery cell structure in one embodiment of this application.

[0029] Figure 2 This is a schematic diagram of the structure of the color development layer in one embodiment of this application.

[0030] Figure 3 This is a schematic diagram of the structure of a multilayer sheet in one embodiment of this application.

[0031] Figure 4 This is a schematic diagram of the structure of a multilayer sheet in another embodiment of this application.

[0032] Figure 5 This is a schematic diagram of the structure of a multilayer sheet in another embodiment of this application.

[0033] Figure 6 This is a schematic diagram of the structure of a multilayer sheet in another embodiment of this application.

[0034] Figure 7 This is a schematic diagram of the structure of a multilayer sheet in another embodiment of this application.

[0035] Figure 8 This is a schematic diagram of the structure of a multilayer sheet in another embodiment of this application.

[0036] Explanation of main component symbols

[0037] 100 cells

[0038] Electrode assembly 200

[0039] Bag 300

[0040] Developing layer 10

[0041] basal layer 11

[0042] Dye layer 12

[0043] Dye capsule 12a

[0044] Casing 12b

[0045] 12c dye filler

[0046] First polymer layer 21

[0047] Second polymer layer 22

[0048] Metal layer 30

[0049] 40 film layers Detailed Implementation

[0050] The technical solution of this application will now be described with reference to the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments.

[0051] It should be noted that when a component is described as "fixed to" another component, it can be directly on the other component or may have a component in between. When a component is considered "connected to" another component, it can be directly connected to the other component or may have a component in between. When a component is considered "set on" another component, it can be directly set on the other component or may have a component in between. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "or / and" as used herein includes any and all combinations of one or more of the associated listed items.

[0053] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0054] Please see Figure 1One embodiment of this application provides a battery cell 100, which includes an electrode assembly 200 and a pouch 300 for housing the electrode assembly 200. See also... Figure 2 The bag 300 is made of multi-layer sheet material. The multi-layer sheet includes a color developing layer 10. The color developing layer 10 includes an adjacent base layer 11 and a dye layer 12. When subjected to pressure exceeding a predetermined threshold or temperature exceeding a predetermined threshold, the dye layer 12 can dye the base layer 11, causing a color difference in the base layer 11. This allows for observation to determine whether the battery cell 100 is subjected to excessive pressure, excessive temperature, or uneven heat / pressure, without the need to disassemble and analyze the battery cell 100.

[0055] Please see Figure 2 In some embodiments, the dye layer 12 includes a plurality of dye capsules 12a, which are uniformly distributed on the substrate layer 11. Each dye capsule 12a includes a shell 12b and a dye filler 12c. The shell 12b encloses the dye filler 12c. The shell 12b is configured to rupture when subjected to a predetermined pressure threshold or a predetermined temperature threshold, and upon rupture, it can release the enclosed dye filler 12c. The released dye filler 12c can contact the substrate layer 11 and cause the substrate layer 11 to change color. Specifically, when the color developing layer 10 is subjected to excessive pressure or excessive temperature in a local area, only the dye capsules 12a distributed in that area rupture, and the dye filler 12c released by the dye capsules 12a in that area only dyes the substrate layer 11 in that area, so that the substrate layer 11 remains in its original color in other areas not subjected to excessive pressure or excessive temperature, and only changes color in areas subjected to excessive pressure or excessive temperature, thereby facilitating the observation and judgment of the specific location of excessive pressure or excessive temperature in the battery cell 100.

[0056] In some embodiments, the dyeing filler 12c is an acidic substance, and the base layer 11 is an acid-reactive colorant. For example, the acidic substance can be at least one of HCl, HBr, HI, HNO3, HF, H2C2O4, or HClO4, and the base layer 11 can be an acid-reactive colorant such as air-dried litmus coating. The litmus turns red upon contact with HCl or HClO4, causing the base layer 11 to appear red in areas subjected to excessive pressure or temperature. In other embodiments, the dyeing filler 12c is an alkaline substance, and the base layer 11 is an alkaline colorant. For example, the base layer 11 can be a phenolphthalein coating or a litmus coating. Phenolphthalein or litmus turns blue upon contact with an alkaline substance, causing the base layer 11 to appear blue in areas subjected to excessive pressure or temperature. In other embodiments, the base layer 11 can also be a methyl orange coating, and the dyeing filler 12c is an acidic substance; the methyl orange coating turns orange-yellow upon contact with acid. In other embodiments, the base layer 11 and the dyeing filler 12c can also be other materials, and may change to other colors upon contact, such as purple or green.

[0057] In some embodiments, the thickness of the dye layer 12 ranges from 3 μm to 20 μm, and the thickness of the substrate layer 11 ranges from 3 μm to 20 μm.

[0058] In some embodiments, the plurality of dye capsules 12a and the base layer 11 can be combined by means of adhesive bonding, thermoplastic bonding or surface spraying.

[0059] In some embodiments, the dye layer 12 includes an adhesive for bonding the dye capsule 12a to the substrate layer. The adhesive may be a commonly used acrylic adhesive, epoxy resin adhesive, anaerobic adhesive, UV adhesive (ultraviolet light curing type), hot melt adhesive, pressure sensitive adhesive, or latex adhesive, etc.

[0060] Please see Figure 3 In some embodiments, the multilayer sheet further includes a first polymer layer 21, with a color-developing layer 10 adhered to the first polymer layer 21, and the color-developing layer 10 being the outermost layer of the multilayer sheet for observing color changes. The base layer 11 is located between the dye layer 12 and the first polymer layer 21. In other embodiments, such as... Figure 4 As shown, the dye layer 12 can also be located between the base layer 11 and the first polymer layer 21.

[0061] Please see Figure 5 In some embodiments, the multilayer sheet further includes a metal layer 30 and a first polymer layer 21, with the color-developing layer 10 located between the metal layer 30 and the first polymer layer 21. The first polymer layer 21 is the outermost layer of the multilayer sheet, and the metal layer 30 is closer to the electrode assembly 200 than the first polymer layer 21. In some embodiments, the dye layer 12 is located between the substrate layer 11 and the metal layer 30. In other embodiments, such as... Figure 5 As shown, the base layer 11 can also be located between the dye layer 12 and the metal layer 30. This structure can keep the outer surface of the battery cell 100 from discoloring for aesthetic purposes. The discoloration can be observed by disassembling the multi-layer sheet to determine whether the pressure and temperature of the battery cell 100 exceed the threshold or are uneven.

[0062] Please see Figure 6 In some embodiments, the multilayer sheet further includes a first polymer layer 21, a second polymer layer 22, and a metal layer 30. The metal layer 30 is located between the first polymer layer 21 and the second polymer layer 22, with the first polymer layer 21 being the outer layer and the second polymer layer 22 being the inner layer. The surface of the second polymer layer 22 faces the surface of the electrode assembly 200. The color-developing layer 10 is bonded to the second polymer layer 22, that is, the second polymer layer 22 is disposed between the color-developing layer 10 and the electrode assembly 200. In some embodiments, such as Figure 6 As shown, the base layer 11 is located between the dye layer 12 and the second polymer layer 22. In other embodiments, such as Figure 7As shown, the dye layer 12 can also be located between the base layer 11 and the second polymer layer 22. This structure can keep the outer surface of the battery cell 100 from discoloring for aesthetic purposes. The discoloration can then be observed by disassembling the multi-layer sheet to determine whether the pressure and temperature of the battery cell 100 exceed the threshold or are uneven.

[0063] In some embodiments, the first polymer layer 21 may be a polyamide material, such as nylon materials like polybutadiene adipamide / polycaprolactam, or a crystalline saturated polyester, such as polyethylene terephthalate (PET) or polybutylene terephthalate (PBT). In some embodiments, the second polymer layer 22 may be an olefin polymer (polypropylene material), such as an olefin polymer layer like polypropylene film (PP, CPP, OPP, MPP). In some embodiments, the metal layer may be an aluminum layer, a stainless steel layer, or a composite material (such as an aluminized packaging film).

[0064] Specifically, in some embodiments, the first polymer layer 21 can be a nylon layer, the second polymer layer 22 can be a PP layer, and the metal layer 30 can be an aluminum layer. In some embodiments, the thickness of the first polymer layer 21 ranges from 10 μm to 15 μm, the thickness of the metal layer 30 ranges from 22 μm to 50 μm, and the thickness of the second polymer layer 22 ranges from 10 μm to 80 μm.

[0065] Specifically, the thickness of the metal layer 30 ranges from 24μm to 35μm. If the metal layer 30 is too thin, the strength will be insufficient, while if the metal layer 30 is too thick, it will increase the overall weight of the cell 100.

[0066] In other embodiments, the first polymer layer 21 may also be made of polyethylene terephthalate (PET) for a protective function. The second polymer layer 22 may also be made of polypropylene; specifically, the second polymer layer 22 may be a polypropylene cast film, i.e., a polypropylene film produced using a casting process, for a sealing function.

[0067] Specifically, the thickness of the second polymer layer 22 ranges from 24 μm to 35 μm. If the second polymer layer 22 is too thin, it cannot effectively protect the metal layer 30; while if the second polymer layer 22 is too thick, it will affect the heat dissipation and cratering effect.

[0068] In some embodiments, the first polymer layer 21, the second polymer layer 22, and the metal layer 30 are connected by an adhesive layer, and the adhesive material used in the adhesive layer may include at least one of acrylic resin, epoxy resin, or polyurethane.

[0069] Please see Figure 8In some embodiments, the multilayer sheet further includes a film layer 40. The film layer 40 is used to adhere the dye layer 12, which is located between the substrate layer 11 and the film layer 40, and the film layer 40 is the outermost layer of the multilayer sheet. The film layer 40 can be peeled off from the multilayer sheet, and the dye layer 12 can be peeled off from the substrate layer 11 along with the film layer 40. As an exemplary example, the film layer 40 is a polyester polymer film. In use, the color of the substrate layer 11 is first observed to determine whether the pressure and temperature of the battery cell 100 exceed a threshold or are uneven. If there is no color change, the film layer 40 is peeled off to reduce the thickness of the multilayer sheet and increase the energy density of the battery cell 100 during use.

[0070] One embodiment of this application also provides an electrochemical device, including a battery cell 100.

[0071] One embodiment of this application also provides an electrical device, including the electrochemical device described above.

[0072] The aforementioned battery cell 100, through the dye layer 12, can dye the substrate layer 11 when subjected to pressure or temperature exceeding a threshold, resulting in color differences on the surface of the substrate layer 11. This allows for observation and judgment of whether the pressure and temperature of the battery cell 100 exceed the threshold or are uneven without disassembling the cell. This facilitates timely interception of battery cells 100 that have exceeded the threshold or are unevenly subjected to pressure or temperature due to abnormalities in the production process before being released to the market. It reduces the potential risk of uneven adhesion between the anode and cathode within the battery cell 100, increases the bonding stability of the battery cell 100 interface, reduces the proportion of abnormal expansion in the later stages of cycling, and reduces the occurrence of problems such as bulging in the final product. The aforementioned electrochemical device and electrical equipment, through the battery cell 100, reduce the probability of failure due to excessive or uneven pressure or temperature on the battery cell, thus improving the safety of the battery cell.

[0073] Furthermore, those skilled in the art should recognize that the above embodiments are merely illustrative of this application and are not intended to limit this application. Any appropriate changes and variations made to the above embodiments within the essential spirit and scope of this application fall within the scope of this application's disclosure.

Claims

1. A battery cell, comprising an electrode assembly and a pouch housing the electrode assembly, characterized in that, The bag is made of a multi-layer sheet, which includes a color developing layer, an adjacent base layer and a dye layer, and a plurality of dye capsules, which are uniformly adhered to the base layer. The dye layer is configured to dye the base layer when subjected to pressure exceeding a predetermined pressure or temperature exceeding a predetermined temperature threshold during cell formation. The multilayer sheet further includes a first polymer layer, and the base layer is located between the dye layer and the first polymer layer; The multilayer sheet further includes a metal layer, and the first polymer layer is located between the metal layer and the color-developing layer; The multilayer sheet further includes a second polymer layer, and the metal layer is disposed between the first polymer layer and the second polymer layer; The multilayer sheet further includes a film layer that is bonded to the dye layer and is the outermost layer of the multilayer sheet. When the base layer does not change color, the dye layer is configured to be peeled off from the base layer along with the film layer.

2. The battery cell as described in claim 1, characterized in that, The membrane is a polyester polymer membrane.

3. The battery cell as described in claim 1, characterized in that, The dye layer is located between the substrate layer and the film layer.

4. The battery cell as described in claim 1, characterized in that, Each of the dye capsules includes a shell and a dye filler, the shell enclosing the dye filler, the shell being configured to rupture and release the dye filler when subjected to pressure exceeding a predetermined threshold or temperature exceeding a predetermined threshold.

5. The battery cell as described in claim 4, characterized in that, The dyeing filler includes an acidic substance, and the base layer includes a substance that develops color when exposed to acid.

6. The battery cell as described in claim 5, characterized in that, The acidic substance includes at least one of HCl, HBr, HI, HNO3, HF, H2C2O4 or HClO4, and the base layer includes a litmus coating.

7. The battery cell as described in claim 4, characterized in that, The dyeing filler includes an alkaline substance, and the base layer includes a substance that develops color when exposed to alkali.

8. The battery cell as described in claim 7, characterized in that... The substrate layer includes a phenolphthalein coating.

9. The battery cell as described in claim 1, characterized in that, The base layer and the dye layer are combined by at least one of the following methods: adhesive bonding, thermoplastic bonding, roll forming, or surface spraying.

10. The battery cell as described in claim 1, characterized in that, The thickness of the dye layer ranges from 3μm to 20μm, and the thickness of the substrate layer ranges from 3μm to 20μm.

11. An electrochemical device, characterized in that, Includes the battery cell as described in any one of claims 1-10.

12. An electrical appliance, characterized in that, Includes the electrochemical device as described in claim 11.

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