WO2021196000A1 - 电芯、电池及电子设备 - Google Patents

电芯、电池及电子设备 Download PDF

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Publication number
WO2021196000A1
WO2021196000A1 PCT/CN2020/082540 CN2020082540W WO2021196000A1 WO 2021196000 A1 WO2021196000 A1 WO 2021196000A1 CN 2020082540 W CN2020082540 W CN 2020082540W WO 2021196000 A1 WO2021196000 A1 WO 2021196000A1
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WIPO (PCT)
Prior art keywords
layer
tab
area
battery cell
battery
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PCT/CN2020/082540
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English (en)
French (fr)
Inventor
闫东阳
曾巧
肖良针
Original Assignee
宁德新能源科技有限公司
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Application filed by 宁德新能源科技有限公司 filed Critical 宁德新能源科技有限公司
Priority to CN202080011261.7A priority Critical patent/CN113454837B/zh
Priority to PCT/CN2020/082540 priority patent/WO2021196000A1/zh
Priority to EP20928459.5A priority patent/EP4131586A4/en
Publication of WO2021196000A1 publication Critical patent/WO2021196000A1/zh

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/30—Arrangements for facilitating escape of gases
    • H01M50/342—Non-re-sealable arrangements
    • H01M50/3425—Non-re-sealable arrangements in the form of rupturable membranes or weakened parts, e.g. pierced with the aid of a sharp member
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/102—Primary casings; Jackets or wrappings characterised by their shape or physical structure
    • H01M50/105—Pouches or flexible bags
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/116—Primary casings; Jackets or wrappings characterised by the material
    • H01M50/124—Primary casings; Jackets or wrappings characterised by the material having a layered structure
    • H01M50/126—Primary casings; Jackets or wrappings characterised by the material having a layered structure comprising three or more layers
    • H01M50/129—Primary casings; Jackets or wrappings characterised by the material having a layered structure comprising three or more layers with two or more layers of only organic material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/131—Primary casings; Jackets or wrappings characterised by physical properties, e.g. gas permeability, size or heat resistance
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/131—Primary casings; Jackets or wrappings characterised by physical properties, e.g. gas permeability, size or heat resistance
    • H01M50/133—Thickness
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/172—Arrangements of electric connectors penetrating the casing
    • H01M50/174—Arrangements of electric connectors penetrating the casing adapted for the shape of the cells
    • H01M50/178—Arrangements of electric connectors penetrating the casing adapted for the shape of the cells for pouch or flexible bag cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/183—Sealing members
    • H01M50/186—Sealing members characterised by the disposition of the sealing members
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/183—Sealing members
    • H01M50/19—Sealing members characterised by the material
    • H01M50/193—Organic material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/183—Sealing members
    • H01M50/19—Sealing members characterised by the material
    • H01M50/197—Sealing members characterised by the material having a layered structure
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/183—Sealing members
    • H01M50/19—Sealing members characterised by the material
    • H01M50/198—Sealing members characterised by the material characterised by physical properties, e.g. adhesiveness or hardness
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/30—Arrangements for facilitating escape of gases
    • H01M50/383—Flame arresting or ignition-preventing means
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/543—Terminals
    • H01M50/547—Terminals characterised by the disposition of the terminals on the cells
    • H01M50/55—Terminals characterised by the disposition of the terminals on the cells on the same side of the cell
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/543—Terminals
    • H01M50/552—Terminals characterised by their shape
    • H01M50/553—Terminals adapted for prismatic, pouch or rectangular cells
    • H01M50/557—Plate-shaped terminals
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • This application relates to an energy storage device, and more particularly to a battery, a battery including the battery, and an electronic device including the battery.
  • the battery cell may reach higher and higher temperatures during the charging process. As the temperature continues to rise, the safety performance of the battery cell gradually declines. More specifically, at extremely high temperatures, the battery cell may generate heat abnormally, which may further cause accidents such as fires and explosions.
  • the cathode material, anode material, and electrolyte are generally replaced to avoid the generation of higher heat.
  • this method of replacing materials may not only lead to an increase in cost, but also may damage other aspects of the performance of the battery.
  • the use of cathode and anode materials with better thermal stability improves their safety performance, they may reduce their energy density and impair the performance of fast charging.
  • This application aims to solve at least one of the above-mentioned technical problems in the prior art, and to provide a battery with good heat dissipation effect and high safety performance in a high-temperature environment.
  • the application also provides a battery including the battery and an electronic device including the battery.
  • the battery cell provided by the embodiment of the present application includes an electrode assembly and a packaging bag containing the electrode assembly, the packaging bag includes a sealing portion, and the electrode assembly includes a first tab and a second tab.
  • the sealing portion includes: a first area and a second area. At least a part of the first tab and the second tab pass through the first region, the packaging strength of the first region is S1, and in the length direction of the battery core, the The width is W1; the second area is connected to the first area, the packaging strength of the second area is S2, and in the length direction of the battery core, the width of the second area is W2.
  • the S1, W1, S2, and W2 satisfy the following relational expressions:
  • S1, S2, W1 are located in the following ranges: 0.5N/m ⁇ S1 ⁇ 10N/m, 0.8S1 ⁇ S2 ⁇ 3.4S1; 1.5mm ⁇ W1 ⁇ 3.0mm.
  • the packaging bag includes a first packaging film and a second packaging film
  • the first packaging film includes a first fusion layer
  • the second packaging film includes a first fusion layer Oppositely disposed second fusion layer
  • the first fusion layer and the second fusion layer are jointly sealed to form the sealing portion and the accommodating space for accommodating the electrode assembly.
  • the first fusion layer and the second fusion layer may be layers of hot-press sealing substances.
  • the electrode assembly further includes a first glue layer opposite to the first fusion layer and a second glue layer opposite to the second fusion layer, and the first tab is arranged Between the first glue layer and the second glue layer, the first glue layer and the second glue layer are respectively disposed between the first fusion layer and the second fusion layer to form The first area through which the first tab can penetrate.
  • the electrode assembly further includes a third adhesive layer opposite to the first fusion layer and a fourth adhesive layer opposite to the second fusion layer, and the second electrode The ears are arranged between the third glue layer and the fourth glue layer, and the third glue layer and the fourth glue layer are respectively arranged between the first fusion layer and the second fusion layer To form the first area for the second tab to pass through.
  • the second adhesive layer, the third adhesive layer, and the fourth adhesive layer may have the same structure and materials as the first adhesive layer, and of course, they may also have different The structure and materials.
  • the first adhesive layer has a single-layer structure with a melting point of 100°C to 150°C.
  • the first adhesive layer may be a layer of hot-pressing sealing material.
  • the first adhesive layer has a double-layer structure, which includes: a first layer opposite to the first fusion layer, and the melting point of the first layer is 100°C to 170°C; and The second layer is opposite to the first tab, and the melting point of the second layer is 105°C to 145°C.
  • the first adhesive layer has a three-layer structure, including: a first layer, which is opposite to the first fusion layer, and the melting point of the first layer is 100°C to 170°C; Layer, which is opposite to the first tab, and the second layer has a melting point of 100°C to 170°C; and a third layer, which is arranged between the first layer and the second layer, the The melting point of the third layer is 200°C to 300°C.
  • first adhesive layer described above can also be applied to the second adhesive layer, the third adhesive layer, and the fourth adhesive layer. That is, in each embodiment, the second adhesive layer, the third adhesive layer, and the fourth adhesive layer may also have any of the above-mentioned structures.
  • the second packaging film has the same structure as the first packaging film.
  • the first packaging film is taken as an example for description.
  • the first packaging film includes the first fusion layer.
  • the melting point of the first fusion layer is 105° C. to 165° C.
  • the material may be a hot-pressing sealing substance.
  • the first packaging film has a three-layer structure, which further includes a barrier substance layer and a metal layer sandwiched between the barrier substance layer and the first fusion layer.
  • the first packaging film has a four-layer structure, which further includes two barrier material layers laminated on each other and sandwiched between one of the barrier material layer and the first fusion layer Between the metal layers.
  • the first packaging film has a five-layer structure, and from the inside to the outside, the first fusion layer, the first bonding layer, the metal layer, the second bonding layer, and the Barrier material layer.
  • the first packaging film has a six-layer structure, which from the inside to the outside is the first fusion layer, the metal layer, the first adhesive layer, the first barrier substance layer, The second adhesive layer and the second barrier substance layer.
  • first packaging film described above can also be applied to the second packaging film. That is, in each embodiment, the second packaging film may also have any of the above-mentioned structures.
  • An embodiment of the application also provides a battery, which includes any of the above-mentioned battery cells.
  • an embodiment of the present application also provides an electronic device, which includes a battery and a housing for accommodating the battery, and the battery includes any of the above-mentioned battery cells.
  • the sealing strength of the different areas of the sealing part of the battery cell is significantly different (that is, the sealing strength of the first area through which the first tab and the second tab pass is S1, the width W1, and the other areas of the sealing part ( The package strength of the second area) is between S2 and width W2, which satisfies this relationship: ), so that when the cell is swollen inside in a high temperature environment, the impact force generated by the air pressure inside the cell will have a greater impact on the area (the first area) where the sealing strength is weaker, so this area Since it cannot withstand high pressure, it opens first, allowing heat to be effectively dissipated from there.
  • the battery core is packaged in areas with weak strength in a high-temperature environment. Will open first, so the heat generated by the battery cell can be quickly and effectively dissipated through this area. It goes without saying that this will reduce the risk of fire and explosion caused by the accumulation of heat of the battery, thereby greatly improving the safety performance of the battery in a high-temperature environment.
  • Fig. 1 is a schematic front view of a battery core provided according to the present application, which schematically shows the front structure of the battery core;
  • FIG. 2 is a schematic top view of the cell shown in FIG. 1, which schematically shows the top cross-sectional structure of the cell;
  • Fig. 3A is a partial enlarged view of F of the battery cell shown in Fig. 2, which shows the partial structure of the first area a (the area penetrated by the first tab) on the left side. Open state
  • Figure 3B is similar to Figure 3A, but also shows the partial structure of the first region a, but different from Figure 3A, at this time the region is in an open state, which is a way of opening (the first adhesive layer and the second The glue layer is squeezed to form an opening);
  • FIG. 3C is similar to FIG. 3B, and also shows the structure of the first region a in an open state, but the opening method (the second fusion layer and the second glue layer are squeezed to form an opening) is different from that of FIG. 3B;
  • FIG. 4A is a partial enlarged view of G of the battery cell shown in FIG. 2, which shows the partial structure of the second area b (the area through which the non-tab area penetrates) of the sealing portion of the battery cell. At this time, the area In an unopened state;
  • Figure 4B is similar to Figure 4A, and also shows the partial structure of the second region b, but differs from Figure 4A in that the region is in an open state at this time, which is an open method (the first fusion layer A And the second fusion layer A'are squeezed to form an opening);
  • Figure 4C is similar to Figure 4B, and also shows the structure of the second region b in an open state, but the open method (the side of the second fusion layer A'close to the metal layer D is squeezed to form an opening) and the figure 4B is different;
  • 5A-5C are cross-sectional views of the first adhesive layer, which respectively show three different structures in which the first adhesive layer is a single layer, a double layer, and a three layer;
  • 6A-6D are cross-sectional views of the first packaging film, which respectively show that the first packaging film has four different structures of three layers, four layers, five layers, and six layers.
  • Fig. 1 shows a schematic front view of a battery cell provided according to the present application.
  • the battery cell includes a packaging bag 1 and an electrode assembly 2.
  • the packaging bag 1 may contain electrolyte (not shown in the figure) inside, and the packaging bag 1 contains the electrode assembly 2. That is, a part of the electrode assembly 2 (the lower part in the figure) is located inside the packaging bag 1 and is immersed in the electrolyte, while the other part (the upper part in the figure) is located outside the packaging bag 1.
  • the electrode assembly 2 includes a first tab 101 and a second tab 102, the first tab 101 and the second tab 102 from the top of the packaging bag 1 (according to The orientation shown in Figure 1) extends.
  • the top of the packaging bag 1 is a sealing part (hence also called a top seal), and the sealing part includes:
  • the first area a can be understood as the tab area of the sealing part
  • the second area b is transversely connected to the first area a, but no tab passes through this area. Therefore, the second area b can be understood as a non-tab area of the sealing portion.
  • the sealing portion (top in FIG. 1) of the packaging bag 1 is defined by the tab area (that is, the first area a) through which the first tab 101 and the second tab 102 pass. ) And other regions (ie, non-tab region, the above-mentioned second region b).
  • the tab area and the non- tab area of the sealing portion of the packaging bag 1 have different packaging strengths.
  • the overall long body of the cell is T1.
  • the width of the first region a is W1; the width of the second region b is W2; the packaging strength of the first region a is S1, and the second region b
  • the package strength of is S2, then the S1, W1, S2, and W2 satisfy the following relationship:
  • the tab area a and the non-tab area b of the sealed portion of the battery designed according to this relationship have different packaging strengths, so the packaging strength of the entire sealing portion is not uniform, that is, the packaging strength of the non-tab area b is greater than that of the tabs.
  • Encapsulation strength of area a Due to such structural parameters, when the cell is bloated in a high temperature environment, the area with weaker package strength (tab area a) will have a stronger impact on the pressure inside the cell than the package strength.
  • the area (non-tab area b) is opened more preferentially, allowing heat to escape from the preferentially opened opening as soon as possible, thereby greatly improving the safety performance of the battery cell in a high-temperature environment, and reducing the accumulation of heat due to the battery cell The possibility of fire, explosion and other dangers caused by it.
  • the packaging strength S1 of the tab region a is: 0.5N/m ⁇ S1 ⁇ 10N/m; the packaging strength S2 of the non- tab region b is: 1.2S1 ⁇ S2 ⁇ 2.8S1.
  • the cell with the package strength S1 and S2 in this range has better safety, and the top seal of the cell is easier to open at high temperature.
  • the packaging strength S1 of the tab area a is: 2.0N/m ⁇ S1 ⁇ 8.0N/m; the packaging strength S2 of the non-tab area b is: 1.5S1 ⁇ S2 ⁇ 2.5S1.
  • the packaging strength S1 of the tab area a is: 2.9N/m ⁇ S1 ⁇ 4.5N/m; the packaging strength S2 of the non- tab area b is: 1.8S1 ⁇ S2 ⁇ 2.2 S1.
  • the packaging strength S1 of the tab area a is 3.9 N/m; the packaging strength S2 of the non- tab area (b) is 1.3 S1, which is Example 6 in Table 1 below.
  • S1 and S2 are within the following numerical range: 0.5N/m ⁇ S1 ⁇ 10N/m, 0.8S1 ⁇ S2 ⁇ 3.4S1.
  • the size of W1 is 1.5mm ⁇ W1 ⁇ 3.0mm.
  • the battery cell designed according to this parameter range not only helps to realize the difference in packaging strength between the non-tab area and the tab area of the sealing part on the top of the battery cell, but also minimizes the loss of the energy density of the battery cell.
  • the packaging bag 1 includes a first packaging film 105 and a second packaging film 105 ′, which are bonded together to form the packaging bag 1.
  • the first packaging film 105 includes a first fusion layer A
  • the second packaging film 105' includes a second fusion layer A'disposed opposite to the first fusion layer A.
  • a fusion layer A and the second fusion layer A′ are jointly sealed to form the sealing portion and the accommodating space for accommodating the electrode assemblies 1 and 2.
  • the melting point of the first fusion layer A is 105°C to 165°C.
  • the electrode assemblies 1, 2 further include a first adhesive layer 103 opposite to the first fusion layer A and a second adhesive layer 104 opposite to the second fusion layer A', so
  • the first tab 101 is arranged between the first glue layer 103 and the second glue layer 104, and the first glue layer 103 and the second glue layer 104 are respectively arranged on the first fusion layer A and the second fusion layer A′ form a first area a for the first tab 101 to pass through.
  • the electrode assemblies 1, 2 further include a third glue layer 105 opposite to the first fusion layer A and a fourth glue layer opposite to the second fusion layer A' Layer 106, the second tab 102 is arranged between the third glue layer 105 and the fourth glue layer 106, and the third glue layer 105 and the fourth glue layer 106 are respectively arranged on the Between the first fusion layer A and the second fusion layer A′, another first region a for the second tab 102 to pass through is formed.
  • opposite in this application means that two layers are adjacent and in contact with each other, or even bonded to each other (for example, bonded by melting), the same hereinafter.
  • FIG. 3A is a partial enlarged view at F of FIG. 2 and shows a partial structure of the first area a on the left side in FIG. 2.
  • the area is in an unopened state at this time.
  • the temperature of the battery cell continues to increase as the charging process progresses, and the pressure inside the battery cell (ie, the inside of the packaging bag 1) also continues to increase, and this pressure will impact the sealed part of the battery cell ( Namely, the tab area a and the non tab area b). Under the effect of this pressure, the tab area a with weak encapsulation strength will be opened first.
  • the opening method may be as shown in FIG. 3B.
  • the first adhesive layer 103 and the second adhesive layer 104 are squeezed apart by the pressure.
  • An opening 100 is formed between the two, or as shown in FIG. 3C, the second adhesive layer 104 and the second fusion layer A'are squeezed apart by pressure to form an opening 100 between the two, or the first A glue layer 103 and the first fusion layer A are squeezed apart by pressure, forming an opening 100 between them (that is, symmetrical to the shape of FIG. 3C, not shown in the figure).
  • FIG. 4A is a partial enlarged view at G of FIG. 2, showing the partial structure of the second area b (the area where the non-tab area penetrates) of the sealing portion of the battery core.
  • the area is in an unopened state at this time.
  • the tab area b may also expand to form further heat dissipation holes.
  • the non-tab area b may be expanded in the manner shown in FIG.
  • both the tab area a and the non-tab area b form a heat dissipation opening, that is, the entire sealing portion of the packaging bag of the battery cell forms a plurality of heat dissipation openings. Obviously, this will help dissipate the heat of the battery as soon as possible, thereby reducing the risk of fire or explosion due to abnormal overheating of the battery.
  • first adhesive layer the second adhesive layer, the third adhesive layer and the fourth adhesive layer may have the same structure and material, of course, they may also have different structures and materials.
  • first adhesive layer takes the first adhesive layer as an example for description.
  • the first adhesive layer 103 is a single layer structure 1031 (for example, a layer of heat-pressing sealing material, which may be PP (polypropylene) or PPA (polyphthalate) Formamide) or CPP (chlorinated polypropylene), etc.), the melting point of the first adhesive layer 1031 is 100°C to 150°C.
  • the glue layer has a simple structure and low cost.
  • the first adhesive layer 103 is a two-layer structure, which includes: a first layer 1031, which is opposite to the first fusion layer A, and the first The melting point of the layer 1031 is 100°C to 170°C; and the second layer 1032 is opposite to the first tab 101, and the melting point of the second layer 1032 is 105°C to 145°C.
  • the first layer 1031 and the second layer 1032 are made of different materials.
  • the first layer 1031 is polypropylene
  • the second layer 1032 is polyethylene propylene copolymer.
  • the use of double-layer structure tab glue is more beneficial to the safety of the battery cell at high temperatures.
  • the second layer 1032 of the double-layer structure tab glue has a lower temperature.
  • the top seals the tab
  • the interface between the second layer 1032 of the tab glue and the first tab 101 in the area is weaker than the interface of the single-layer glue layer cell and is easier to open, which is conducive to heat dissipation.
  • the first adhesive layer 103 includes: a first layer 1031, which is opposite to the first fusion layer A, and the melting point of the first layer is 100°C ⁇ 170°C; the second layer 1032, which is opposite to the first tab 101, the melting point of the second layer is 105°C ⁇ 145°C; and the third layer 1033, which is arranged on the first layer 1031 and Among the second layers 1032, the melting point of the third layer 1033 is 200°C to 300°C.
  • the first layer 1031 and the second layer 1032 may be the same material or different materials.
  • the third layer 1033 is made of a different material from the first layer 1031 and the second layer 1032, and therefore has a higher melting point. Therefore, when the battery core will produce heat dissipation openings at a high temperature, the second layer 1032 and the first tab 101 or the first layer 1031 and the first fusion layer A will open first. The space between the third layer 1033 and the first layer 1031 and the second layer 1032 is finally opened.
  • the three-layer adhesive layer has higher mechanical strength and hardness due to the higher melting point of the middle layer, and the degree of deformation of the lug adhesive is low after hot pressing. The consistency of the battery core is better, and the battery using the three-layer structure adhesive layer will have a longer service life.
  • the second adhesive layer, the third adhesive layer, and the fourth adhesive layer may also have any of the above-mentioned structures.
  • the second adhesive layer may have a single-layer, double-layer or three-layer structure.
  • the third adhesive layer and the fourth adhesive layer can also have different structures.
  • the second packaging film 105' may have the same structure as the first packaging film 105. Therefore, the first packaging film 105 is taken as an example for description below.
  • the first packaging film 105 has a three-layer structure, which includes the first fusion layer A as described above, and a barrier material layer C and clamped on the barrier material.
  • the metal layer D between the layer C and the first fusion layer A.
  • the first fusion layer A realizes the fusion bonding with the tab glue; the metal layer D can make the packaging film 105 have a certain rigidity; the barrier substance layer C is used to protect the metal layer D, which can be made of insulating material.
  • the packaging film of this structure is relatively low in cost.
  • the first packaging film 105 has a four-layer structure, which includes the first fusion layer A as described above, two barrier material layers C stacked on each other, and one The metal layer D between the barrier substance layer C and the first fusion layer A.
  • the function of each layer is similar to the above-mentioned embodiment, wherein the two barrier material layers C can be made of different materials.
  • the first packaging film 105 has a five-layer structure, which from the inner side to the outer side is the first fusion layer A, the first adhesive layer E1, the metal layer D, and the second Adhesive layer E2 and barrier material layer C.
  • the first bonding layer E1 bonds the first fusion layer A and the metal layer D; the second bonding layer E2 bonds the metal layer D and the barrier substance layer C. Since the two adhesive layers are provided, the layers of the first packaging film 105 are firmly bonded together, so that the first packaging film 105 has better rigidity and tightness as a whole.
  • the first packaging film 105 has a six-layer structure, which from the inner side to the outer side is the first fusion layer A, the metal layer D, the first adhesive layer E1, and the first The barrier substance layer C, the second adhesive layer E2 and the second barrier substance layer C.
  • the battery provided by the present application includes the battery cell as described above, and the battery cell can reduce the risk of fire or explosion when the battery is charged, thereby improving the safety performance of the battery.
  • the electronic device provided by the present application may include a battery and a casing for accommodating the battery, and the battery includes the above-mentioned battery cell.
  • the battery containing the battery cell can improve the safety performance of the entire electronic device without sacrificing other aspects of performance such as fast charging of the battery.
  • this value is a CT (Computed Tomography) measurement value, and the unit is mm.
  • the batteries can pass the test 100% after being heated at a temperature of 140°C for 60 minutes (that is, the top seal of the batteries is opened, and the batteries do not fire or explode. , It is considered not invalid).
  • the non-tab area b of the battery cell For example, by widening the width W2 of the area.
  • the encapsulation of the non-tab area of the cell is achieved by melting at high temperature by two layers of hot-pressing sealing material (ie, the "fusion layer” mentioned above).
  • the change time is mainly affected by the width of the seal area.
  • the cell length T1 of conventional consumer secondary batteries is in the range of 10mm ⁇ T1 ⁇ 200mm, and the width of the sealing area on the top of the cell is 1.5mm ⁇ W1 ⁇ 3.0mm. This will not only help achieve non-uniform strength packaging, but also Minimize energy density loss as much as possible,
  • a sealing material with a lower melting point can be selected, such as tab glue, which can be selected to test the melting point value in the range of 100°C to 170°C or even 105°C to 145°C. As long as one of the positive electrode tab and the negative electrode tab can be realized.
  • the sealing of the tab area a is to seal the tab together with the packaging film.
  • the melting point of the hot-pressing sealing material (ie, the aforementioned fusion layer) of the packaging film is also possible to reduce the melting point of the hot-pressing sealing material (ie, the aforementioned fusion layer) of the packaging film to achieve the weakening of the packaging strength of the tab area a at high temperatures, which is preferred It is a material whose melting point is in the range of 105°C to 165°C.
  • spatially relative terms such as “below”, “below”, “lower”, “above”, “upper”, “lower”, “left side”, “ The “right side” and so on describe the relationship between one component or feature and another component or feature as illustrated in the figure.
  • the spatial relative terms are intended to cover different orientations of the device in use or operation.
  • the device can be oriented in other ways (rotated by 90 degrees or in other orientations), and the spatial relative descriptors used in this application can also be interpreted accordingly. It should be understood that when a component is referred to as being “connected to” or “coupled to” another component, it can be directly connected or coupled to the other component, or intervening components may be present.

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Abstract

本申请涉及电芯、电池及电子设备。该电芯包括电极组件和收容所述电极组件的包装袋，所述包装袋包括密封部，所述电极组件包括第一极耳和第二极耳。其中，所述密封部包括：第一区域和第二区域。所述第一极耳和第二极耳的至少一部分从所述第一区域穿出，所述第一区域的封装强度为S1，在所述电芯的长度方向上，所述第一区域的宽度为W1；所述第二区域与所述第一区域连接，所述第二区域的封装强度为S2，在所述电芯的长度方向上，所述第二区域的宽度为W2。其中，所述S1、W1、S2和W2满足以下关系式： (I) 按照本申请所提供的电芯在高温环境下散热效果好，安全性能高，减少了电芯由于热量累积而导致的起火、爆炸等危险的发生。

Description

电芯、电池及电子设备 技术领域
本申请涉及一种储能装置，尤其涉及一种电芯，包括该电芯的电池，以及包含该电池的电子设备。
背景技术
随着电芯能量密度和使用电压的不断提升，电芯在充电过程中可能会达到越来越高的温度。而随着温度的不断升高，电芯的安全性能逐步下降。更具体地说，在极高的温度下，电芯可能会异常发热，而异常发热又可能会进一步引起火灾、爆炸等事故。
现有技术中，一般采用更换阴极材料、阳极材料和电解液(如，使用热稳定性更好的材料)的方式来避免产生较高的热量。然而，更换材料这种方式不仅可能会导致成本的增加，而且有可能损害电芯其他方面的性能。例如，采用热稳定性更好的阴极和阳极材料虽然提高了其安全性能，但可能会降低其能量密度且损害了快速充电的性能。
因此，如何在不影响电芯其他方面的性能的前提下提高电芯在高温下的安全性能，尤其是如何提升电芯在充电过程中的散热效果，是有待研究的一个重要课题。
发明内容
本申请旨在至少解决现有技术中存在的上述技术问题之一，提供一种在高温环境下散热效果好，安全性能高的电芯。本申请同时还提供了包括该电芯的电池及包含该电池的电子设备。
根据本申请实施例所提供的电芯，其包括电极组件和收容所述电极组件的包装袋，所述包装袋包括密封部，所述电极组件包括第一极耳和第二极耳。其中，所述密封部包括：第一区域和第二区域。所述第一极耳和第二极耳的至少一部分从所述第一区域穿出，所述第一区域的封装强度为S1，在所述电芯的长度方向上，所述第一区域的宽度为W1；所述第二区域与所述第一区域连接，所述第二区域的封装强度为S2，在所述电芯的长度方向上，所述第二区域的宽度为W2。其中，所述S1、W1、S2和W2满足以下关系式：
Figure PCTCN2020082540-appb-000001
优选地，S1、S2、W1位于如下范围内：0.5N/m＜S1＜10N/m，0.8S1≤S2≤3.4S1；1.5mm＜W1＜3.0mm。
在本申请的一种实施方案，所述包装袋包括第一包装膜和第二包装膜，所述第一包装膜包括第一融合层，所述第二包装膜包括与所述第一融合层相对设置的第二融合层，所述第一融合层与所述第二融合层共同密封形成所述密封部和用于收容所述电极组件的容纳空间。第一融合层和第二融合层可为热压密封物质层。
在本申请的上述实施方案中，所述电极组件还包括与所述第一融合层相对的第一胶层和与所述第二融合层相对的第二胶层，所述第一极耳设置在所述第一胶层与所述第二胶层之间，所述第一胶层和所述第二胶层分别设置在所述第一融合层和所述第二融合层之间以形成供所述第一极耳穿出的所述第一区域。
同时，在本申请的上述实施方案中，所述电极组件还包括与所述第一融合层相对的第三胶层和与所述第二融合层相对的第四胶层，所述第二极耳设置在所述第三胶层与所述第四胶层之间，所述第三胶层和所述第四胶层分别设置在所述第一融合层和所述第二融合层之间以形成供所述第二极耳穿出的所述第一区域。
在本申请的各实施例中，所述第二胶层、所述第三胶层和所述第四胶层可具有与所述第一胶层相同的结构和材料，当然，也可以具有不同的结构和材料。下面以第一胶层为例进行说明。
作为一种实施方式，所述第一胶层为单层结构，其熔点为100℃～150℃。例如，所述第一胶层可为热压密封物质层。
作为另一种实施方式，所述第一胶层为双层结构，其包括：第一层，其与所述第一融合层相对，所述第一层的熔点为100℃～170℃；及第二层，其与所述第一极耳相对，所述第二层的熔点为105℃～145℃。
作为再一种实施方式，所述第一胶层为三层结构，包括：第一层，其与所述第一融合层相对，所述第一层的熔点为100℃～170℃；第二层，其与所述第一极耳相对，所述第二层的熔点为100℃～170℃；及第三层，其设置在所述第一层与所述第二层之间，所述第三层的熔点为200℃～300℃。
上述第一胶层的各种结构也可以适用于所述第二胶层、所述第三胶层和所述第四胶层。即，在各个实施例中，所述第二胶层、所述第三胶层和所述第四胶层也可以是上述任意一种结构。
在本申请的各个实施例中，所述第二包装膜具有与所述第一包装膜相同的结构。下面以第一包装膜为例进行说明。
如前所述，第一包装膜包括所述第一融合层。在本申请的实施例中，所述第一融合层的熔点为105℃～165℃，其材料可以是热压密封物质。
在本申请的一个实施例中，所述第一包装膜为三层结构，其还包括阻挡物质层和夹持于所述阻挡物质层和所述第一融合层之间的金属层。
在本申请的另一个实施例中，所述第一包装膜为四层结构，其还包括两个彼此层叠的阻挡物质层和夹持于其中一个所述阻挡物质层和所述第一融合层之间的金属层。
在本申请的再一个实施例中，所述第一包装膜为五层结构，其从内侧到外侧依次为所述第一融合层、第一粘结层、金属层、第二粘结层和阻挡物质层。
在本申请的还一个实施例中，所述第一包装膜为六层结构，其从内侧到外侧依为所述第一融合层、金属层、第一粘结层、第一阻挡物质层、第二粘结层和第二阻挡物质层。
上述第一包装膜的的各种结构也可以适用于所述第二包装膜。即，在各个实施例中，所述第二包装膜也可以是上述任意一种结构。
本申请实施例还提供了一种电池，其包括如上所述的任意一种电芯。
另外，本申请实施例还提供了一种电子设备，其包括电池和用于收容所述电池的壳体，所述电池包括上述的任意一种电芯。
根据本申请所提供的电芯，相比现有技术具有如下优越的技术效果：
由于电芯的密封部不同区域的密封强度具有明显差异(即，供第一极耳和第二极耳从中穿出的第一区域的封装强度为S1、宽度W1，与密封部的其他区域(第二区域)的封装强度为S2、宽度W2之间，满足这样的关系式：
Figure PCTCN2020082540-appb-000002
)，使得当电芯在高温环境下内部发生胀气后，电芯内部的气压所产生的冲击力会对密封部的封装强度较弱的区域(第一区域)产生更大的冲击，于是该区域由于无法承受较大气压而优先张开，从而允许热量从该处有效地散出。即，由于该电芯的密封部的极耳区域(第一区域)和非极耳区域(第二区域)具有不均匀的封装强度的设计，而使得电芯在高温环境下封装强度弱的区域会先张开，因而电芯所产生的热量能够通过该区域快速、有效地散发。不言而喻，这将减少电芯由于热量累积而导致的起火、爆炸等危险的发生，因而大大提高了电芯在高温环境下的安全性能。
附图说明
为了更清楚地说明本申请的具体实施方式及其优越的技术效果，下面结合附图对本申请实施例进行详细描述。
图1是根据本申请所提供的电芯的主视示意图，其示意性地示出了电芯的正面结构；
图2是如图1所示的电芯的俯视示意图，其示意性地示出了电芯的顶部截面结构；
图3A是图2所示的电芯的F处的局部放大视图，其示出了左侧的第一区域a(第一极耳所穿出的区域)的局部结构，此时该区域处于未张开的状态；
图3B与图3A类似，也示出了第一区域a的局部结构，但与图3A不同，此时该区域处于张开的状态，这是一种张开方式(第一胶层和第二胶层被挤压而形成开口)；
图3C与图3B类似，也示出了第一区域a处于张开状态的结构，但张开方式(第二融合层和第二胶层被挤压而形成开口)与图3B不同；
图4A是图2所示的电芯的G处的局部放大视图，其示出了电芯的密封部的第二区域b(非极耳区域穿出的区域)的局部结构，此时该区域处于未张开的状态；
图4B与图4A类似，也示出了第二区域b的局部结构，但与图4A不同的是，此时该区域处于张开的状态，这是一种张开方式(第一融合层A和第二融合层A′被挤压而形成开口)；
图4C与图4B类似，也示出了第二区域b处于张开状态的结构，但张开方式(第二融合层A′的靠近金属层D的一侧被挤压而形成开口)与图4B不同；
图5A-5C为第一胶层的截面图，其分别示出了第一胶层为单层、双层和三层的三种不同的结构；以及
图6A-6D为第一包装膜的截面图，其分别示出了第一包装膜为三层、四层、五层和六层的四种不同的结构。
具体实施方式
下面结合附图具体描述本申请的实施例。通过参考附图来阅读关于下面具体实施例的描述，就更容易理解本申请的各个方面。需要说明的是，这些实施例仅仅是示例性的，其仅用于解释、说明本申请的技术方案，而并非对本申请的限制。本领域技术人员在这些实施 例的基础上，可以作出各种变型和变换，所有以等同方式变换获得的技术方案均属于本申请的保护范围。
图1示出了根据本申请所提供的电芯的主视示意图。
如图1所示，该电芯包括包装袋1和电极组件2。所述包装袋1可包含位于其内部的电解液(图中未示)，且所述包装袋1收容所述电极组件2。即，电极组件2的一部分(图中的下部)位于所述包装袋1的内部，并浸泡在电解液中，而另一部分(图中的上部)位于包装袋1的外部。
具体而言，如图1中所示，所述电极组件2包括第一极耳101和第二极耳102，第一极耳101和第二极耳102从所述包装袋1的顶部(按照图1中所示的方位)伸出。而所述包装袋1的顶部为密封部(因此也称为顶封)，所述密封部包括：
第一区域a，所述第一极耳101和第二极耳102的至少一部分从所述第一区域a穿出。因此，可以将第一区域a理解为密封部的极耳区域；
第二区域b，其与所述第一区域a横向连接，但没有极耳从该区域穿过。因此，可以将第二区域b理解为密封部的非极耳区域。
换言之，在本发明中，所述包装袋1的密封部(图1中的顶部)由供所述第一极耳101和第二极耳102穿过的极耳区域(即，第一区域a)和其他区域(即，非极耳区域，上述的第二区域b)构成。在本发明中，所述包装袋1的密封部的极耳区域和非极耳区域具有不同的封装强度。
具体而言，如图1中所示，电芯的总体长体为T1。在所述电芯的长度方向上，所述第一区域a的宽度为W1；所述第二区域b的宽度为W2；所述第一区域a的封装强度为S1，所述第二区域b的封装强度为S2，那么所述S1、W1、S2和W2满足以下关系式：
Figure PCTCN2020082540-appb-000003
Figure PCTCN2020082540-appb-000004
按照该关系式设计的电芯的密封部的极耳区域a和非极耳区域b具有不同的封装强度，因而整个密封部的封装强度不均匀，即非极耳区域b的封装强度大于极耳区域a的封装强度。由于具有这样的结构参数，因此，当电芯在高温环境下内部发生胀气后，封装强度较弱的区域(极耳区域a)在电芯内部的气压冲击力的作用会比封装强度较强的区域(非极耳区域b)更优先地张开，从而允许热量从该优先张开的开口尽快地散出，从而大大提高了电芯在高温环境下的安全性能，减小电芯由于热量累积而导致的起火、爆 炸等危险发生的可能性。
在图1所示的实施例中，W1＝W2。那么上述关系式变为：S1≤S2≤3S1。也就是说，在极耳区域a和非极耳区域b的宽度相等的情况下，非极耳区域b的封装强度S2大于或等于极耳区域a的封装强度S1，但小于等于所述顶封极耳区域a的封装强度S1的3倍。在实践中，可根据电芯的整体尺寸、极耳及极耳胶(下文中提到的“胶层”)等诸多因素来确定极耳区域a和非极耳区域b所应达到的封装强度S1、S2。例如，可选择为：1.2S1≤S2≤2.8S1；1.5S1≤S2≤2.5S1；1.8S1≤S2≤2.2S1；S2＝1.3S1(详述下文中的实验数据部分(表1))。
例如，在某个实施例中，所述极耳区域a的封装强度S1为：0.5N/m＜S1＜10N/m；所述非极耳区域b的封装强度S2为：1.2S1≤S2≤2.8S1。根据测试，封装强度S1、S2位于该范围内的电芯具有更好的安全性，电芯在高温下其顶封更容易张开。更优选地，所述极耳区域a的封装强度S1为：2.0N/m＜S1＜8.0N/m；所述非极耳区域b的封装强度S2为：1.5S1≤S2≤2.5S1。例如，在下表1的实施例1中，S1＝2.9；S2＝7.0；因此S2≈2.4S1，此时当电芯以140℃加热60分钟时，电芯可100％通过测试，电芯顶封张开。在再一个实施例中，所述极耳区域a的封装强度S1为：2.9N/m＜S1＜4.5N/m；所述非极耳区域b的封装强度S2为：1.8S1≤S2≤2.2S1。例如，在下表1的实施例3中，S1＝3.3；S2＝5.1；因此S2≈2.16S1，此时当电芯以140℃加热60分钟时，电芯可100％通过测试，电芯顶封张开。在还一个实施例中，所述极耳区域a的封装强度S1为3.9N/m；所述非极耳区域(b)的封装强度S2为1.3S1，即下表1的实施例6，此时当电芯以140℃加热60分钟时，电芯可100％通过测试，电芯顶封张开。
在本申请的优先实施例中，S1、S2位于如下数值范围内：0.5N/m＜S1＜10N/m，0.8S1≤S2≤3.4S1。而W1的尺寸为1.5mm＜W1＜3.0mm。按照该参数范围设计的电芯，不仅有助于实现电芯顶部的密封部的非极耳区域和极耳区域的封装强度的不同，而且使电芯能量密度的损失最小。
参见图2，其为图1所示的本发明的电芯的一个实施例的俯视示意图。如图中所示，所述包装袋1包括第一包装膜105和第二包装膜105′，二者贴合在一起，构成包装袋1。如图中所示，所述第一包装膜105包括第一融合层A，所述第二包装膜105′包括与所述第一融合层A相对设置的第二融合层A′，所述第一融合层A与所述第二融合层A′共同密封形成所述密封部和用于收容所述电极组件1、2的容纳空间。所述第一融合层A的熔点为105℃～165℃。
如图2中所示，所述电极组件1、2还包括与所述第一融合层A相对的第一胶层103和与所述第二融合层A′相对的第二胶层104，所述第一极耳101设置在所述第一胶层103与所述第二胶层104之间，所述第一胶层103和所述第二胶层104分别设置在所述第一融合层A和所述第二融合层A′中以形成供所述第一极耳101穿出的一个第一区域a。
类似地，参见图2中的右侧，所述电极组件1、2还包括与所述第一融合层A相对的第三胶层105和与所述第二融合层A′相对的第四胶层106，所述第二极耳102设置在所述第三胶层105与所述第四胶层106之间，所述第三胶层105和所述第四胶层106分别设置在所述第一融合层A和所述第二融合层A′之中以形成供所述第二极耳102穿出的另一个第一区域a。
结合附图可知，本申请中的“相对”是指两层相邻且彼此接触，甚至彼此粘结在一起(例如，通过熔融方式粘结)，下同。
参见图3A，其为图2的F处的局部放大视图，示出了图2中左侧的第一区域a的局部结构。如图中所示，此时该区域处于未张开的状态。当电芯被充电时，随着充电过程的进行电芯的温度不断升高，而电芯内部(即，包装袋1内部)的压力也不断增大，该压力会冲击电芯的密封部分(即极耳区域a和非极耳区域b)。在该压力的作用，封装强度弱的极耳区域a会首先张开，其张开方式可能是如图3B所示，所述第一胶层103与所述第二胶层104被压力挤开，在二者之间形成开口100，也可能是如图3C所示，在第二胶层104和所述第二融合层A′被压力挤开，在二者之间形成开口100，或者第一胶层103和所述第一融合层A被压力挤开，在二者之间形成开口100(即与图3C的形状对称，图中未示)。
参见图4A，其是图2的G处的局部放大视图，示出了电芯的密封部的第二区域b(非极耳区域穿出的区域)的局部结构。如图4A中所示，此时该区域处于未张开的状态。在电芯的充电过程中，当极耳区域a由于电芯的高温而张开以后，如果电芯的温度继续上升，导致极耳区域a所张开的开口不足以有效地散热，此时非极耳区域b也可能会张开，形成进一步的散热孔。例如，非极耳区域b有可能以图4B所示的方式张开，即第一融合层A和第二融合层A′被压力挤压而形成开口200，也可能以图4C所示的方式，第二融合层A′的靠近金属层D(详见下述)的一侧被压力挤压而形成开口200。在这种情况下，极耳区域a和非极耳区域b都形成了散热开口，即，电芯的包装袋的整个密封部形成多个散热开口。很显然，这将有助于将电芯的热量尽快地散发，从而减少了电芯由于异常过热而发生着火或爆炸的危险。
下面具体介绍极耳的各胶层的结构。在本发明中，第一胶层、第二胶层、第三胶层和 第四胶层可具有相同的结构和材料，当然，也可以具有不同的结构和材料。下面以第一胶层为例进行说明。
参见图5A，在本申请的一种实施例中，所述第一胶层103为单层结构1031(例如，热压密封物质层，其可以是PP(聚丙烯)或PPA(聚邻苯二甲酰胺)或CPP(氯化聚丙烯)等)，所述第一胶层1031的熔点为100℃～150℃。这种胶层结构简单，成本较低廉。
参见图5B，在本申请的另一种实施例中，所述第一胶层103为双层结构，其包括：第一层1031，其与所述第一融合层A相对，所述第一层1031的熔点为100℃～170℃；及第二层1032，其与所述第一极耳101相对，所述第二层1032的熔点为105℃～145℃。此时所述第一层1031和所述第二层1032为不同的材料，例如第一层1031为聚丙烯，第二层1032为聚乙烯丙烯共聚物。采用双层结构极耳胶对于电芯高温下的安全性更加有利，这是因为：双层结构极耳胶的第二层1032温度较低，在电芯高温胀气的情况下，顶封极耳区域中极耳胶的第二层1032和第一极耳101之间的界面较单层胶层电芯的界面更加薄弱，更易于张开，因而有利于散热。
参见图5C，在本申请的再一种实施例中，所述第一胶层103包括：第一层1031，其与所述第一融合层A相对，所述第一层的熔点为100℃～170℃；第二层1032，其与所述第一极耳101相对，所述第二层的熔点为105℃～145℃；及第三层1033，其设置在所述第一层1031与所述第二层1032之间，所述第三层1033的熔点为200℃～300℃。此时所述第一层1031和所述第二层1032可为相同的材料，也可为不同的材料。所述第三层1033为第一层1031和所述第二层1032不同的材料，因而具有高于它们的熔点。因此，当电芯在高温下将产生散热开口时，第二层1032与所述第一极耳101之间或第一层1031与所述第一融合层A之间将先张开。所述第三层1033与所述第一层1031和所述第层1032之间最后再张开。与单层和两层结构的胶层相比，三层结构的胶层由于中间层具有较高的熔点，因而具有更高的机械强度和硬度，在热压封装后极耳胶变形程度低，电芯一致性更优，同时采用三层结构胶层的的电芯将具有更长的使用寿命。
在各个实施例中，所述第二胶层、所述第三胶层和所述第四胶层也可以是上述任意一种结构。例如，当第一胶层为单层结构时，所述第二胶层可为单层、双层或三层结构。同理，第三胶层和第四胶层也可具有不同的结构。
在本发明中，所述第二包装膜105′可具有与所述第一包装膜105相同的结构。因此，下面以第一包装膜105为例进行说明。
参见图6A-6D，其示出了第一包装膜105的各种实施例的截面图。其中，在图6A所示的实施例中，所述第一包装膜105为三层结构，其包括如前所述的第一融合层A、以及阻挡物质层C和夹持于所述阻挡物质层C和所述第一融合层A之间的金属层D。第一融合层A实现与极耳胶的融合粘结；金属层D能使得包装膜105具有一定的刚度；阻挡物质层C用于保护金属层D，其可由绝缘材料制成。这种结构的包装膜相对于而言成本较低廉。
在图6B所示的实施例中，所述第一包装膜105为四层结构，其包括如前所述的第一融合层A、两个彼此层叠的阻挡物质层C和夹持于其中一个所述阻挡物质层C和所述第一融合层A之间的金属层D。各层的功能与上述实施例类似，其中，两层阻挡物质层C可由不同的材料制成。
在图6C所示的实施例中，所述第一包装膜105为五层结构，其从内侧到外侧依次为所述第一融合层A、第一粘结层E1、金属层D、第二粘结层E2、和阻挡物质层C。第一粘结层E1将第一融合层A和金属层D相粘结；第二粘结层E2将金属层D和阻挡物质层C相粘结。由于设置了两个粘结层，使得第一包装膜105的各层均牢固地粘结在一起，从而第一包装膜105整体具有较好的刚性和密封性。
在图6D所示的实施例中，所述第一包装膜105为六层结构，其从内侧到外侧依为所述第一融合层A、金属层D、第一粘结层E1、第一阻挡物质层C、第二粘结层E2和第二阻挡物质层C。在该实施例中，具有两层阻挡物质层和两个粘结层，更进一步提升包装膜105整体的密封性。
按照本申请所提供的电池，包含如上所述的电芯，该电芯能减少电池充电时发生起火或爆炸的危险，因而提高了电池的安全性能。
根据本申请所提供的电子设备，可以包括电池和用于收容所述电池的壳体，所述电池包括上述的电芯。含有该电芯的电池能提升整个电子设备的安全性能，同时并不牺性电池的快速充电等其他方面的性能。
下面结合表1中具体的实验数据进一步说明本申请的技术方案所产生的技术效果：
表1对比例1-2和实施例1-8的实验数据和技术效果
Figure PCTCN2020082540-appb-000005
____________________
1 W2＝W1，该数值为CT(Computed Tomography)测量值，单位为mm。
2高铁拉力机测量值，单位为N/m；S2也是。
3 DSC测试值，单位℃；负极极耳胶测试及熔合层熔点也是。
Figure PCTCN2020082540-appb-000006
从上表1可以看出，在对比例1中，以130℃的温度对该电芯加热60分钟的情况下，电芯胀气通过，但顶封不张开；而以140℃的温度加热60分钟的情况下，该电芯有大约50％的几率会起火失效，电芯顶封不张开，测试不通过。
相对之下，按照实施例1-8所提供的电芯，在以140℃的温度加热60分钟后电芯可100％通过测试(即电芯顶封张开，并且电芯不起火，不爆炸，认为不失效)。对于实施例7和8，即使以150℃的温度加热60分钟后，仍有部分电芯通过测试。在实施例1-8中，S1和S2的关系大约分别是：S2＝2.41S1；S2＝1.54S1；S2＝2.16S1；S2＝1.57S1；S2＝2.11S1；S2＝1.31S1；S2＝1.74S1；S2＝2.34S1。由此可见，按照本发明所提供的电芯在高温下的安全性能大大提高。
最后，顺便说明，在具体电芯的设计和制造过程中，可以通过两个方面相结合来实现非极耳区域和极耳区域达到不同的封装强度：
(1)提高电芯的非极耳区域b的封装强度。例如，通过加宽该区域的宽度W2。电芯非极耳区域的封装是通过两层热压密封物质层(即上文所述的“融合层”)在高温下熔融实现的密封，其密封后的封装强度在封装设备和温度条件不变时，主要受封印区域宽度的影响。目前常规消费类二次电池的电芯长度T1范围为10mm＜T1＜200mm，电芯顶部密封区域的宽度范围为1.5mm＜W1＜3.0mm，这样既有助于实现非均匀强度封装，又能尽可能减少能量密度损失，
(2)弱化电芯的极耳区域a的封装强度。例如可选用熔点较低的密封材料，如极耳胶可选择测试熔点值在100℃～170℃甚至105℃～145℃范围内。只要正极极耳和负极极耳其中之一可以实现即可。另外极耳区域a的密封是极耳与包装膜一起密封，也可以通过 降低包装膜热压密封物质(即前述的熔合层)的熔点来实现极耳区域a的高温下封装强度弱化，其优选是熔点值位于105℃～165℃范围内的材料。
如本申请中所使用，为易于描述可在本申请中使用空间相对术语例如“下面”、“下方”、“下部”、“上方”、“上部”、“下部”、“左侧”、“右侧”等描述如图中所说明的一个组件或特征与另一组件或特征的关系。除图中所描绘的定向之外，空间相对术语意图涵盖在使用或操作中的装置的不同定向。设备可以其它方式定向(旋转90度或处于其它定向)，且本申请中所使用的空间相对描述词同样可相应地进行解释。应理解，当一组件被称为“连接到”或“耦合到”另一组件时，其可直接连接或耦合到所述另一组件，或可存在中间组件。
在本申请中，术语“约”通常意指在给定值或范围的±10％、±5％、±1％或±0.5％内。范围可在本申请中表示为从一个端点到另一端点或在两个端点之间。除非另外指定，否则本申请中所公开的所有范围包括端点。
上文中概述本申请的若干实施例和细节方面的特征。本领域技术人员在不脱离本申请的精神和范围的前提下，还可作出各种不同变化、替代和改变，所有这些等效构造均属于本申请的保护范围。

Claims (10)

  1. 一种电芯，包括电极组件和收容所述电极组件的包装袋(1)，所述包装袋(1)包括密封部，所述电极组件包括第一极耳(101)和第二极耳(102)，其特征在于，所述密封部包括：
    第一区域(a)，所述第一极耳(101)和第二极耳(102)的至少一部分从所述第一区域(a)穿出，所述第一区域(a)的封装强度为S1，在所述电芯的长度方向上，所述第一区域的宽度为W1；及
    第二区域(b)，其与所述第一区域(a)连接，所述第二区域(b)的封装强度为S2，在所述电芯的长度方向上，所述第二区域(b)的宽度为W2；
    其中，所述S1、W1、S2和W2满足以下关系式：
    Figure PCTCN2020082540-appb-100001
  2. 根据权利要求1所述的电芯，其特征在于：0.5N/m＜S1＜10N/m，0.8S1≤S2≤3.4S1。
  3. 根据权利要求1所述的电芯，其特征在于：1.5mm＜W1＜3.0mm。
  4. 根据权利要求1所述的电芯，其特征在于：所述包装袋(1)包括第一包装膜(105)和第二包装膜(105′)，所述第一包装膜(105)包括第一融合层(A)，所述第二包装膜(105′)包括与所述第一融合层(A)相对设置的第二融合层(A′)，所述第一融合层(A)与所述第二融合层(A′)共同密封形成所述密封部和用于收容所述电极组件的容纳空间；及
    所述电极组件还包括与所述第一融合层(A)相对的第一胶层(103)和与所述第二融合层(A′)相对的第二胶层(104)，所述第一极耳(101)设置在所述第一胶层(103)与所述第二胶层(104)之间，所述第一胶层(103)和所述第二胶层(104)分别设置在所述第一融合层(A)和所述第二融合层(A′)之间以形成供所述第一极耳(101)穿出的所述第一区域(a)。
  5. 根据权利要求4所述的电芯，其特征在于：所述第一胶层(103)为单层结构(1031)，所述第一胶层(103)的熔点为100℃～150℃。
  6. 根据权利要求4所述的电芯，其特征在于：所述第一胶层(103)包括：
    第一层(1031)，其与所述第一融合层(A)相对，所述第一层(1031)的熔点为100℃～170℃；及
    第二层(1032)，其与所述第一极耳(101)相对，所述第二层(1032)的熔点为105℃～145℃。
  7. 根据权利要求4所述的电芯，其特征在于：所述第一胶层(103)包括：
    第一层(1031)，其与所述第一融合层(A)相对，所述第一层的熔点为100℃～170℃；
    第二层(1032)，其与所述第一极耳(101)相对，所述第二层的熔点为105℃～145℃；及
    第三层(1033)，其设置在所述第一层(1031)与所述第二层(1032)之间，所述第三层(1033)的熔点为200℃～300℃。
  8. 根据权利要求4所述的电芯，其特征在于：所述第一融合层(A)的熔点为105℃～165℃。
  9. 一种电池，其特征在于，包括根据权利要求1-8中任意一项所述的电芯。
  10. 一种电子设备，其特征在于，包括电池和用于收容所述电池的壳体，所述电池包括根据权利要求1-8中任意一项所述的电芯。
PCT/CN2020/082540 2020-03-31 2020-03-31 电芯、电池及电子设备 WO2021196000A1 (zh)

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