WO2022181652A1 - Élément de protection et bloc-batterie - Google Patents

Élément de protection et bloc-batterie Download PDF

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Publication number
WO2022181652A1
WO2022181652A1 PCT/JP2022/007434 JP2022007434W WO2022181652A1 WO 2022181652 A1 WO2022181652 A1 WO 2022181652A1 JP 2022007434 W JP2022007434 W JP 2022007434W WO 2022181652 A1 WO2022181652 A1 WO 2022181652A1
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WO
WIPO (PCT)
Prior art keywords
heating element
glass layer
fusible conductor
current
insulating substrate
Prior art date
Application number
PCT/JP2022/007434
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English (en)
Japanese (ja)
Inventor
千智 小森
Original Assignee
デクセリアルズ株式会社
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Filing date
Publication date
Application filed by デクセリアルズ株式会社 filed Critical デクセリアルズ株式会社
Publication of WO2022181652A1 publication Critical patent/WO2022181652A1/fr

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H37/00—Thermally-actuated switches
    • H01H37/74—Switches in which only the opening movement or only the closing movement of a contact is effected by heating or cooling
    • H01H37/76—Contact member actuated by melting of fusible material, actuated due to burning of combustible material or due to explosion of explosive material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/44—Methods for charging or discharging
    • 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
    • H01M50/20—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/18—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for batteries; for accumulators
    • 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 technology relates to a protection element that protects a circuit connected to a current path by fusing the current path, and a battery pack using the same.
  • the battery pack In order to ensure the safety of users and electronic devices, the battery pack generally incorporates a number of protection circuits such as overcharge protection and overdischarge protection. It has a function to cut off the output of the battery pack in a predetermined case.
  • a protection element for such a protection circuit for a lithium ion secondary battery or the like a structure is used in which a heating element is provided inside the protection element, and the heat generated by the heating element melts and cuts a fusible conductor on a current path. .
  • lithium-ion secondary batteries have been expanding in recent years, and they have begun to be used in applications with higher currents, such as power tools such as electric screwdrivers, and transportation equipment such as hybrid cars, electric vehicles, and power-assisted bicycles.
  • power tools such as electric screwdrivers
  • transportation equipment such as hybrid cars, electric vehicles, and power-assisted bicycles.
  • a large current exceeding several tens of amperes to 100 amperes may flow. Realization of a protection element corresponding to such a large current capacity is desired.
  • a protective element In order to realize a protective element that can handle such a large current, a protective element has been proposed in which a fusible conductor with an increased cross-sectional area is used and the fusible conductor is connected to the surface of an insulating substrate on which a heating element is formed. ing.
  • FIG. 8A and 8B are diagrams showing an example of the configuration of a conventional protective element, in which (A) is a plan view with the cover member omitted, (B) is a cross-sectional view, and (C) is a bottom view.
  • a protection element 100 shown in FIG. First and second electrodes 102 and 103 connected to the current path of the circuit, a heating element 104 formed on the surface of the insulating substrate 101 and generating heat when energized, an insulating layer 105 covering the heating element 104, and insulation.
  • a heating element lead-out electrode 106 laminated on the layer 105 and connected to the heating element 104 is mounted over the first electrode 102, the heating element lead-out electrode 106, and the second electrode 103 via connection solder. and a fuse element 107 .
  • the heating element 104 is connected to a heating element feeding electrode 108 formed on the surface of the insulating substrate 101 .
  • the heating element power supply electrode 108 is connected to a third external connection electrode 108a formed on the back surface of the insulating substrate 101 via castellations.
  • the heating element 104 is connected to an external power source provided in an external circuit via a third external connection electrode 108a.
  • the current and heat generation of the heating element 104 are constantly controlled by a switch element (not shown) or the like.
  • the heating element 104 is covered with an insulating layer 105 made of a glass layer or the like, and overlapped with a heating element extraction electrode 106 formed on the insulating layer 105 via the insulating layer 105 .
  • the insulating layer 105 is formed by printing and baking glass paste, for example.
  • a fuse element 107 connected between the first and second electrodes 102 and 103 is connected to the heating element extraction electrode 106 .
  • the fuse element 107 is thermally connected to the heating element 104 by being superimposed on the heating element 104 via the insulating layer 105, and is fused when the heating element 104 generates heat when energized.
  • the fuse element 107 is made of a low-melting point metal such as Pb-free solder, a high-melting point metal such as Ag, Cu, or alloys containing these as main components, or has a laminated structure of low-melting point metals and high-melting point metals.
  • the fuse element 107 is connected from the first electrode 102 to the second electrode 103 via the heating element lead-out electrode 106, thereby constituting a part of the current path of the external circuit in which the protection element 100 is incorporated. .
  • the fuse element 107 is fused due to self-heating (Joule heat) when a current exceeding the rated current is applied, or fused due to the heat generated by the heating element 104, thereby disconnecting the first and second electrodes 102 and 103. .
  • the switch element When the protective element 100 needs to cut off the current path of the external circuit, the switch element energizes the heating element 104 . As a result, the heating element 104 generates heat to a high temperature and melts the fuse element 107 incorporated on the current path of the external circuit. The melted conductor of the fuse element 107 is attracted to the heating element extraction electrode 106 and the first and second electrodes 102 and 103 with high wettability. As a result, the fuse element 107 fuses the first electrode 102 to the heating element lead-out electrode 106 to the second electrode 103, thereby cutting off the current path of the external circuit.
  • the voltage of devices using protective elements has increased, and the voltage applied to the heating element has become standardized to exceed 42 V, which is a safe and low voltage.
  • the insulating layer 105 (glass layer) of the protective element is formed very thin (for example, 10 to 10 mm) in order to efficiently transfer the heat of the heating element 104 to the heating element lead-out electrode 106 and the fuse element 107. 40 ⁇ m). Therefore, if there are places where the insulation performance is degraded, such as pinholes that occur in the glass when the glass paste is printed, dielectric breakdown occurs when a voltage is applied to the heating element 104, and the insulation performance is sufficiently reduced. There is a risk that the heating element 104 will be destroyed or the heating element extraction electrode 106 will be damaged before it generates heat.
  • the insulating layer 105 is damaged by the stress caused by the difference in linear expansion due to the temperature difference between the contact surface with the heating element 104 and the other surface, and the material itself of the insulating layer 105 is destroyed. There is also a possibility that the heating element extraction electrode 106 may also be damaged. This tendency increases in the back heater structure in which the heating element 104 and the insulating layer 105 are formed on the back surface of the insulating substrate and the fuse element 107 is not superimposed on the insulating layer 105 .
  • the risk that the fuse element remains unmelted due to damage to the heating element 104 and the heating element extraction electrode 106 due to such dielectric breakdown and hindrance to current interruption increases as the size of the fuse element increases with the increase in voltage and current. , and also increases as the rated voltage increases and the electric field strength increases.
  • the purpose of this technology is to provide a protective element that can safely and quickly cut off a current path without damaging the insulating layer or the heating element, and a battery pack using the same.
  • a protection element includes an insulating substrate, a fusible conductor supported on the insulating substrate, a plurality of current-carrying parts connected to the fusible conductor, and the insulating a heating element provided on a substrate to generate heat when energized; a heating element electrode connected to the heating element and serving as a power supply terminal to the heating element; and a glass layer covering the heating element, The layer has a melting point lower than that of the heating element.
  • a battery pack includes one or more battery cells, a protection element connected to a charging/discharging path of the battery cell to block the charging/discharging path, and a voltage value of the battery cell.
  • a current control element for controlling energization to the protective element the protective element comprising an insulating substrate, a fusible conductor supported on the insulating substrate, and a plurality of current-carrying parts connected to the fusible conductor a heating element provided on the insulating substrate to generate heat when energized; a heating element electrode connected to the heating element and serving as a power supply terminal to the heating element; and a glass layer covering the heating element.
  • the glass layer has a melting point lower than that of the heating element.
  • the glass layer since the glass layer has a lower melting point than the heating element, it softens when the heating element generates heat. Therefore, the stress caused by the temperature difference in the glass layer can be dissipated, the breakage of the glass layer and the resulting insulation breakdown and breakage of the heating element are prevented, and the necessary and sufficient heat is generated to melt the fusible conductor. It is possible to secure the heat generation time of the body.
  • FIG. 1 is a view showing one configuration example of a protective element having a heating element provided on the surface of an insulating substrate, (A) is a plan view showing the cover member omitted, (B) is a cross-sectional view, (C) is a bottom view.
  • 2 is a figure which shows the state which the fusible conductor melt
  • FIG. 3 is a cross-sectional view of a fusible conductor.
  • FIG. 4 is a circuit diagram showing a configuration example of a battery pack.
  • FIG. 5 is a circuit diagram of a protection element.
  • FIG. 6 is a diagram showing one configuration example of a protection element having a heating element provided on the back surface of an insulating substrate
  • A is a plan view showing the cover member omitted
  • B is a cross-sectional view
  • C is a bottom view
  • 7 is a figure which shows the state which the fusible conductor melt
  • A) is a top view which abbreviate
  • (B) is sectional drawing.
  • 8A and 8B are diagrams showing one configuration example of the protective element, in which (A) is a plan view without a cover member, (B) is a cross-sectional view, and (C) is a bottom view.
  • the protective element 1 to which the present technology is applied includes an insulating substrate 2, a fusible conductor 3 supported on the insulating substrate 2, and a fusible conductor 3. a heating element 5 provided on the insulating substrate 2 and generating heat when energized; and a heating element electrode 6 connected to the heating element 5 and serving as a power supply terminal to the heating element 5. and a glass layer 7 covering the heating element 5 , the glass layer 7 having a melting point lower than that of the heating element 5 .
  • a heating element 5 and a glass layer 7 covering the heating element 5 are formed on the surface 2a of the insulating substrate 2 on which the fusible conductor 3 is supported.
  • the conducting portion 4 on the surface 2a of the insulating substrate 2, as the conducting portion 4, a first conducting portion 4a connected to one end of the fusible conductor 3 and a second conducting portion connected to the other end of the fusible conductor 3 A portion 4b is formed.
  • the heating element drawer conducting portion 4c superimposed on the glass layer 7 and also connected to the fusible conductor 3 is formed.
  • the heat dissipation characteristics of the glass layer 7 are partially different, such as the part in contact with the heating element 5 and the part not in contact, and the part in contact with the heating element lead-out current-carrying part 4c and the part not in contact. Therefore, the glass layer 7 is subject to internal stress when the heating element 5 generates heat, which may cause breakage.
  • the glass layer 7 of the protective element 1 since the glass layer 7 of the protective element 1 has a lower melting point than the heating element 5, it softens when the heating element 5 generates heat. Therefore, the stress caused by the temperature difference in the glass layer 7 can be dissipated, the breakage of the glass layer 7 and the resulting dielectric breakdown and the breakage of the heating element 5 can be prevented, and the fusible conductor 3 can be fused. A necessary and sufficient heating time of the heating element 5 can be secured.
  • the fusible conductor 3 constitutes a part of the current path of the external circuit, and the heat generated by the heating element 5 or the overcurrent exceeding the rating will cause it to melt. cuts off the current path.
  • Insulating substrate 2 is made of an insulating material such as alumina, glass ceramics, mullite, or zirconia.
  • the insulating substrate 2 may be made of a material used for a printed wiring board, such as a glass epoxy substrate or a phenolic substrate.
  • First and second conductive portions 4a and 4b are formed at opposite ends of the insulating substrate 2, respectively.
  • the first and second conducting parts 4a and 4b are each formed of a conductive pattern such as Ag or Cu. Further, the surfaces of the first and second conducting parts 4a and 4b are coated with a film such as Ni/Au plating, Ni/Pd plating, or Ni/Pd/Au plating by a known technique such as plating. preferably.
  • the protective element 1 can prevent oxidation of the first and second current-carrying parts 4a and 4b, and prevent fluctuations in ratings due to increases in conduction resistance.
  • the solder for connection that connects the fusible conductor 3 is melted to prevent the first and second current-carrying parts 4a and 4b from being corroded (soldered). be able to.
  • the first conducting portion 4a is continuous from the surface 2a of the insulating substrate 2 to the first external connection electrode 11 formed on the back surface 2b via castellations.
  • the second current-carrying portion 4b is connected from the front surface 2a of the insulating substrate 2 to the second external connection electrode 12 formed on the back surface 2b via castellations.
  • the first and second conducting parts 4a and 4b are electrically connected via the fusible conductor 3 by mounting the fusible conductor 3 via a conductive connecting material such as connection solder.
  • a conductive connecting material such as connection solder.
  • the fusible conductor 3 self-heats (Joule heat) in the first and second current-carrying parts 4a and 4b when a large current exceeding the rating flows through the protective element 1. , or the heat generating element 5 generates heat as the current flows and the fusible conductor 3 melts, thereby disconnecting the connection.
  • the heating element 5 is a conductive member that has a relatively high resistance value and generates heat when energized, and is made of, for example, nichrome, W, Mo, Ru, or a material containing these.
  • the heat generating element 5 is made by mixing powders of these alloys, compositions, or compounds with a resin binder or the like, making a paste, forming a pattern on the insulating substrate 2 using a screen printing technique, and firing the mixture. and the like.
  • the heating element 5 is formed by adjusting a mixed paste of ruthenium oxide paste, silver and glass paste according to a predetermined voltage, forming a film at a predetermined position on the surface 2a of the insulating substrate 2 with a predetermined area, and then , can be formed by performing a firing treatment under appropriate conditions.
  • the shape of the heating element 5 can be appropriately designed, but as shown in FIG. 1, it is preferable to make it substantially rectangular in accordance with the shape of the insulating substrate 2 in order to maximize the heating area.
  • the heating element 5 has one end 5a connected to the first extraction electrode 15 and the other end 5b connected to the second extraction electrode 16 .
  • the first extraction electrode 15 is extracted from the heating element electrode 6 and has the same potential as the heating element electrode 6 when the heating element 5 is energized.
  • the second extraction electrode 16 is extracted from the intermediate electrode 8 provided on the surface 2a of the insulating substrate 2, and when the heating element 5 is energized, it has the same potential as the intermediate electrode 8 and the heating element extraction current-carrying part 4c connected thereto. .
  • the first extraction electrode 15 is drawn from the heating element electrode 6 along one end 5a of the heating element 5, and in the protection element 1 shown in FIG. One side edge of the heating element 5 is overlapped.
  • the second extraction electrode 16 is extracted from the intermediate electrode 8 along the other end portion 5b of the heating element 5, and in the protection element 1 shown in FIG. It extends along the side edge and overlaps the other side edge of the heating element 5 .
  • the heating element electrode 6 and the intermediate electrode 8 are formed on opposite side edges of the insulating substrate 2 different from the side edges where the first and second conducting parts 4a and 4b are provided.
  • the heating element electrode 6 is an electrode that serves as a power supply terminal for the heating element 5, and is connected to one end portion 5a of the heating element 5 via a first extraction electrode 15, and to the insulating substrate 2 via castellations. It is continuous with the third external connection electrode 13 formed on the back surface 2b.
  • the heating element electrode 6, the first and second extraction electrodes 15 and 16, and the intermediate electrode 8 are formed by printing and firing a conductive paste such as Ag or Cu in the same manner as the first and second conducting parts 4a and 4b. can be formed by Further, by forming the electrodes and the current-carrying parts formed on the surface 2a of the insulating substrate 2 from the same material, they can be formed in a single printing and firing process.
  • the heating element electrode 6 is formed by melting the connection solder provided on the electrode of the external circuit board connected to the third external connection electrode 13 by reflow mounting or the like, so that the heating element electrode 6 is formed on the heating element electrode 6 via castellation.
  • a control wall may be provided to prevent the liquid from creeping up and spreading on the heating element electrode 6 .
  • the first and second conducting parts 4a and 4b may be provided with restricting walls.
  • the regulation wall can be formed using an insulating material that does not have wettability to solder, such as glass, solder resist, or insulating adhesive, and can be formed on the heating element electrode 6 by printing or the like.
  • the intermediate electrode 8 is an electrode provided between the heating element 5 and the heating element lead-out current-carrying part 4c laminated on the glass layer 7, is connected to the other end 5b of the heating element 5, and It is connected to the conducting portion 4c.
  • the heating element lead-out energization part 4 c overlaps the heating element 5 via the glass layer 7 and is connected to the meltable conductor 3 .
  • the heating element 5 , the first extraction electrode 15 and the second extraction electrode 16 are covered with the glass layer 7 . Further, on the glass layer 7, a heating element lead-out current-carrying portion 4c is formed.
  • the glass layer 7 serves to protect and insulate the heating element 5.
  • the thickness of the glass layer 7 is formed as thin as 10 to 40 ⁇ m, for example, in order to efficiently transmit the heat of the heating element 5 to the heating element lead-out current-carrying part 4c and the fusible conductor 3 .
  • the glass layer 7 can be formed, for example, by applying and baking a glass-based paste.
  • the glass layer 7 has a lower melting point than the heating element 5 .
  • the glass layer 7 has partially different heat dissipation characteristics, such as a portion in contact with the heating element 5 and the first and second lead electrodes 15 and 16 and a portion not in contact, and a portion in contact with and not in contact with the heating element lead current-carrying portion 4c.
  • the melting point of the glass layer is the same as the melting point of the heating element 5, internal stress is generated when the heating element 5 heats up, which may cause breakage.
  • the glass layer 7 of the protective element 1 since the glass layer 7 of the protective element 1 has a lower melting point than the heating element 5, it softens when the heating element 5 generates heat. Therefore, the stress caused by the temperature difference in the glass layer 7 can be dissipated, the breakage of the glass layer 7 and the resulting dielectric breakdown and the breakage of the heating element 5 can be prevented, and the fusible conductor 3 can be fused. A necessary and sufficient heating time of the heating element 5 can be secured. Similarly, it is possible to prevent the breakage of the heating element lead-out current-carrying portion 4c and prevent the molten conductor of the meltable conductor 3 from remaining unmelted between the first and second current-carrying portions 4a and 4b.
  • the glass layer 7 may have a melting point lower than the heating temperature of the heating element 5. Also by this, the glass layer 7 is softened when the heating element 5 generates heat, and breakage due to internal stress can be prevented.
  • the melting point of the glass layer 7 can be 600° C. or lower.
  • the melting point of the glass layer 7 is preferably higher than the temperature during reflow mounting of the protective element 1 .
  • the glass layer 7 is softened to prevent the positional deviation of the heating element lead-out current-carrying part 4c and the fusible conductor 3 from occurring. can be done.
  • the melting point of the glass layer 7 can be 300° C. or higher.
  • the melting point and firing temperature of the glass layer 7 can be set by adjusting the composition and compounding amount of the glass powder, resin, solvent, etc. that are mixed in the glass paste.
  • the heating element 5 and a current control element or the like formed in the external circuit are connected via the third external connection electrode 13 .
  • the heating element 5 is normally regulated to be energized and generate heat, but is energized via the third external connection electrode 13 at a predetermined timing when the energization path of the external circuit is interrupted and generates heat.
  • the glass layer 7 has a melting point lower than that of the heating element 5, it is softened by the heat generated by the heating element 5. Therefore, in the glass layer 7, the generation of internal stress due to the difference in linear expansion between the portions in contact with the heating element 5 and the first and second extraction electrodes 15 and 16 and the portions not in contact with the heat generating element 5 is suppressed. and damage to the heating element 5 accompanying this can be prevented. In addition, dielectric breakdown (spark) due to breakage of the glass layer 7 and breakage of the heating element 5 can be prevented. And the protection element 1 can ensure heat generation time of the heat generating body 5 necessary and sufficient for fusing the meltable conductor 3 .
  • the protective element 1 connects the first and second conducting parts 4a and 4b by transmitting the heat of the heating element 5 to the fusible conductor 3 via the glass layer 7 and the heating element drawing conducting part 4c.
  • the fusible conductor 3 can be melted.
  • the molten conductor 3a of the fusible conductor 3 agglomerates on the heating element lead-out current-carrying part 4c and on the first and second current-carrying parts 4a and 4b, thereby forming a current path between the first and second current-carrying parts 4a and 4b. blocked.
  • the heating element 5 stops generating heat because its own energization path is cut off.
  • heating element drawer energization part The heating element lead-out current-carrying part 4 c formed on the glass layer 7 is connected at one end to the intermediate electrode 8 and partially overlaps the heating element 5 with the glass layer 7 interposed therebetween.
  • the heating element lead-out energizing portion 4c is connected to the fusible conductor 3 between the first and second energizing portions 4a and 4b via a bonding material such as connection solder.
  • the heating element lead-out energizing portion 4c can be formed by printing and firing a conductive paste such as Ag or Cu, like the first and second energizing portions 4a and 4b. Further, it is preferable that the surface of the heating element lead-out current-carrying portion 4c is coated with a film such as Ni/Au plating, Ni/Pd plating, or Ni/Pd/Au plating by a known technique such as plating. .
  • the fusible conductor 3 is mounted between the first and second current-carrying parts 4a and 4b, and is fused by self-heating (Joule heat) due to heat generated by the energization of the heating element 5 or current exceeding the rating. It cuts off the current path between the first current-carrying portion 4a and the second current-carrying portion 4b.
  • the fusible conductor 3 may be a conductive material that melts due to heat generated by the heating element 5 or an overcurrent state. Alloys, PbIn alloys, ZnAl alloys, InSn alloys, PbAgSn alloys, etc. can be used.
  • the fusible conductor 3 may be a structure containing a high melting point metal and a low melting point metal.
  • the fusible conductor 3 is a laminated structure consisting of an inner layer and an outer layer, and the low melting point metal layer 18 as the inner layer and the high melting point metal layer as the outer layer laminated on the low melting point metal layer 18 19.
  • the fusible conductor 3 is connected to the first and second conducting parts 4a and 4b and the heating element drawing conducting part 4c via a joining material such as connection solder.
  • the low-melting-point metal layer 18 is preferably solder or a metal containing Sn as a main component, and is a material generally called "Pb-free solder".
  • the melting point of the low-melting-point metal layer 18 does not necessarily have to be higher than the temperature of the reflow furnace, and may be melted at about 200.degree.
  • the high-melting-point metal layer 19 is a metal layer laminated on the surface of the low-melting-point metal layer 18, and is, for example, Ag or Cu, or a metal containing one of these as a main component.
  • Such a fusible conductor 3 can be formed by forming a high-melting-point metal layer on a low-melting-point metal foil using a plating technique, or using other known lamination techniques or film-forming techniques. can also be formed. At this time, the fusible conductor 3 may have a structure in which the entire surface of the low-melting-point metal layer 18 is covered with the high-melting-point metal layer 19, or may have a structure covered except for a pair of opposing side surfaces.
  • the fusible conductor 3 may be composed of the high melting point metal layer 19 as an inner layer and the low melting point metal layer 18 as an outer layer, and the low melting point metal layer 18 and the high melting point metal layer 19 are alternately laminated. It can be formed in various configurations, such as a multi-layered structure of three or more layers, an opening provided in a part of the outer layer and a part of the inner layer exposed.
  • the fusible conductor 3 By laminating the high melting point metal layer 19 as an outer layer on the low melting point metal layer 18 serving as an inner layer, the fusible conductor 3 can be melted even when the reflow temperature exceeds the melting temperature of the low melting point metal layer 18. The shape can be maintained as the melt conductor 3, and the melting does not occur. Therefore, the connection between the first and second current-carrying parts 4a and 4b and the heating element lead-out current-carrying part 4c and the fusible conductor 3 and the mounting of the protective element 1 on the external circuit board can be efficiently performed by reflow.
  • the resistance value locally increases or decreases due to the deformation of the fusible conductor 3, preventing fluctuations in fusing characteristics such as not fusing at a predetermined temperature or fusing at less than a predetermined temperature. can do.
  • the fusible conductor 3 does not fuse due to self-heating while a predetermined rated current is flowing. Then, when a current higher than the rated current flows, it melts due to self-heating and cuts off the current path between the first and second conducting parts 4a and 4b. Also, the heating element 5 is energized and melts to generate heat, thereby cutting off the current path between the first and second current-carrying portions 4a and 4b.
  • the melted low-melting-point metal layer 18 of the meltable conductor 3 melts (is soldered) the high-melting-point metal layer 19, so that the high-melting-point metal layer 19 melts at a temperature lower than the melting temperature. Therefore, the fusible conductor 3 can be fused in a short time by using the erosion action of the high-melting-point metal layer 19 by the low-melting-point metal layer 18 .
  • meltable conductor 3a of the meltable conductor 3 is separated by the physical pulling action of the heating element drawer energizing part 4c and the first and second energizing parts 4a and 4b, it is possible to quickly and reliably A current path between the first and second conducting parts 4a and 4b can be interrupted (FIG. 2).
  • the meltable conductor 3 is formed so that the volume of the low-melting-point metal layer 18 is larger than the volume of the high-melting-point metal layer 19 .
  • the fusible conductor 3 is heated by self-heating due to overcurrent or heat generation of the heating element 5, and melts the low-melting-point metal to erode the high-melting-point metal. Therefore, by forming the volume of the low-melting metal layer 18 larger than the volume of the high-melting metal layer 19, the meltable conductor 3 promotes this corrosion action and quickly forms the first and second current-carrying parts 4a. , 4b can be interrupted.
  • the fusible conductor 3 is configured by laminating the high-melting-point metal layer 19 on the low-melting-point metal layer 18 serving as an inner layer, the fusing temperature is significantly reduced compared to conventional chip fuses made of high-melting-point metal. can do. Therefore, the fusible conductor 3 can have a larger cross-sectional area than a chip fuse or the like of the same size, and can greatly improve the current rating. In addition, it can be made smaller and thinner than conventional chip fuses with the same current rating, and is excellent in fast fusing performance.
  • the fusible conductor 3 can improve resistance to surges (pulse resistance) in which an abnormally high voltage is momentarily applied to the electrical system in which the protective element 1 is incorporated. That is, the fusible conductor 3 must not be fused even when a current of 100 A flows for several milliseconds, for example.
  • the fusible conductor 3 since a large current that flows in an extremely short time flows through the surface layer of the conductor (skin effect), the fusible conductor 3 is provided with a high melting point metal layer 19 such as Ag plating with a low resistance value as an outer layer. , current applied by a surge can flow easily, and fusing due to self-heating can be prevented. Therefore, the fusible conductor 3 can greatly improve resistance to surges as compared with conventional fuses made of solder alloys.
  • the fusible conductor 3 may be coated with flux (not shown) to prevent oxidation and improve wettability during fusing.
  • the inside of the protective element 1 is protected by covering the insulating substrate 2 with a case 17 .
  • the case 17 can be formed using, for example, an insulating member such as various engineering plastics, thermoplastics, ceramics, glass epoxy substrates, and the like.
  • the case 17 is arranged on the surface 2a of the insulating substrate 2 so that the fusible conductor 3 expands into a spherical shape when melted, and the molten conductor 3a spreads over the heating element lead-out current-carrying portion 4c and the first and second current-carrying portions 4a and 4b. have sufficient internal space to cohere into
  • Such a protection element 1 is used by being incorporated in a circuit within a battery pack 20 of, for example, a lithium ion secondary battery.
  • the battery pack 20 has a battery stack 25 composed of, for example, a total of four lithium-ion secondary battery cells 21a to 21d.
  • the battery pack 20 includes a battery stack 25, a charge/discharge control circuit 26 that controls charge/discharge of the battery stack 25, and a protection element 1 to which the present invention is applied that cuts off a charge/discharge path when the battery stack 25 malfunctions.
  • a detection circuit 27 for detecting the voltage of the battery cells 21a to 21d and a current control element 28 functioning as a switch element for controlling the operation of the protection element 1 according to the detection result of the detection circuit 27 are provided.
  • the battery stack 25 is a series connection of battery cells 21a to 21d that require control to protect against overcharge and overdischarge. is connected to the charging device 22, and the charging voltage from the charging device 22 is applied. By connecting the positive terminal 20a and the negative terminal 20b of the battery pack 20 charged by the charging device 22 to an electronic device operated by the battery, the electronic device can be operated.
  • the charge/discharge control circuit 26 includes two current control elements 23a and 23b connected in series to the current path between the battery stack 25 and the charging device 22, and a control section that controls the operation of these current control elements 23a and 23b. 24.
  • the current control elements 23a and 23b are composed of, for example, field effect transistors (hereinafter referred to as FETs). Controlling the gate voltage by the control unit 24 causes the current path of the battery stack 25 to move in the charging direction and/or the discharging direction. control the conduction and interruption of The control unit 24 operates by receiving power supply from the charging device 22, and performs current control so as to cut off the current path when the battery stack 25 is over-discharged or over-charged according to the detection result of the detection circuit 27. It controls the operation of the elements 23a, 23b.
  • the protection element 1 is connected, for example, to the charging/discharging current path between the battery stack 25 and the charging/discharging control circuit 26, and its operation is controlled by the current control element 28.
  • the detection circuit 27 is connected to each battery cell 21a-21d, detects the voltage value of each battery cell 21a-21d, and supplies each voltage value to the control section 24 of the charge/discharge control circuit 26. Moreover, the detection circuit 27 outputs a control signal for controlling the current control element 28 when any one of the battery cells 21a to 21d reaches an overcharge voltage or an overdischarge voltage.
  • the current control element 28 is composed of, for example, an FET, and when a detection signal output from the detection circuit 27 causes the voltage value of the battery cells 21a to 21d to exceed a predetermined overdischarge or overcharge state, the current control element 28 is a protective element. 1 is operated to cut off the charging/discharging current path of the battery stack 25 regardless of the switch operation of the current control elements 23a and 23b.
  • the protective element 1 to which the present invention is applied which is used in the battery pack 20 configured as described above, has a circuit configuration as shown in FIG. That is, in the protective element 1, the first external connection electrode 11 is connected to the battery stack 25 side, and the second external connection electrode 12 is connected to the positive electrode terminal 20a side. It is connected in series on the charge/discharge path. In the protection element 1, the heating element 5 is connected to the current control element 28 via the heating element electrode 6 and the third external connection electrode 13, and the heating element 5 is connected to the open end of the battery stack 25. .
  • one end of the heating element 5 is connected to one open end of the fusible conductor 3 and the battery stack 25 via the heating element drawer energization part 4c, and the other end is connected to the third external connection electrode 13 It is connected to the other open ends of the current control element 28 and the battery stack 25 .
  • a power supply path to the heating element 5 whose energization can be controlled by the current control element 28 is formed.
  • the detection circuit 27 detects an abnormal voltage in any one of the battery cells 21a to 21d, it outputs a cutoff signal to the current control element 28.
  • the current control element 28 controls the current to energize the heating element 5 .
  • the protection element 1 current flows from the battery stack 25 to the heating element 5, whereby the heating element 5 starts to generate heat.
  • the fusible conductor 3 melts due to the heat generated by the heating element 5 and cuts off the charge/discharge path of the battery stack 25 .
  • the protection element 1 melts the low melting point metal before fusing the high melting point metal, and the melted low melting point metal provides a high melting point.
  • the fusible conductor 3 can be melted in a short time using the corrosive action of the melting point metal.
  • the melting point of the glass layer 7 is lower than that of the heating element 5.
  • the glass layer 7 is softened when the heating element 5 generates heat, so that the stress generated by the temperature difference in the glass layer 7 can be released. Therefore, the protective element 1 prevents the damage of the glass layer 7 and the resulting breakage between the high potential portion such as the heating element electrode 6, the first lead-out electrode 15 or the heating element 5 and the low potential portion such as the heating element lead-out current-carrying portion 4c. It is possible to prevent a dielectric breakdown (spark) between them and breakage of the heating element 5 and the heating element lead-out current-carrying part 4c. And the protection element 1 can ensure the heating time of the heat generating body 5 necessary and sufficient for fusing the fusible conductor 3, and can cut off the current path safely and quickly.
  • the fusible conductor 3 melts due to self-heating, and the charge/discharge path of the battery pack 20 can be cut off.
  • the fusible conductor 3 is fused by heat generated by the heating element 5 or by self-heating of the fusible conductor 3 due to overcurrent.
  • the protective element 1 is reflow-mounted on a circuit board, or when the circuit board on which the protective element 1 is mounted is further exposed to a high-temperature environment such as reflow heating, the low-melting-point metal becomes the high-melting-point metal.
  • Deformation of the meltable conductor 3 can be suppressed by having a structure covered by. Therefore, the fusible conductor 3 can be prevented from changing its resistance due to the deformation of the fusible conductor 3, and the fusing characteristic can be prevented from changing.
  • the protective element 1 according to the present invention is not limited to being used in battery packs for lithium-ion secondary batteries, but can of course be applied to various uses that require interruption of current paths by electrical signals.
  • a protective element 30 includes a heating element 5, first and second lead-out electrodes 15 and 16 and a glass layer 7 covering them are formed. Further, on the back surface 2b of the insulating substrate 2, a heating element electrode 6, a backside intermediate electrode 8b, and first and second external connection electrodes 11 and 12 are formed.
  • first and second electrodes 4a and 4b In addition, on the surface 2a of the insulating substrate 2, first and second electrodes 4a and 4b, a fusible conductor 3, a heating element lead-out current-carrying portion 4c, and a surface-side intermediate electrode 8a are formed.
  • the second lead-out electrode 16 is led out from the back-side intermediate electrode 8b in the same manner as the intermediate electrode 8 described above.
  • the surface-side intermediate electrode 8a and the back-side intermediate electrode 8b are electrically connected by a castellation formed on the side surface of the insulating substrate 2, a conductive through hole passing through the insulating substrate 2, or the like.
  • the surface-side intermediate electrode 8a is connected to the heating element lead-out energizing portion 4c.
  • the surface-side intermediate electrode 8a and the back-side intermediate electrode 8b can be formed using the same material and the same process as those of the intermediate electrode 8 described above.
  • the heating element lead-out current-carrying part 4c is electrically and thermally connected to the heating element 5 via the front-side intermediate electrode 8a and the back-side intermediate electrode 8b. That is, in the protection element 30, the heating element 5 heats the heating element lead-out current-carrying part 4c through the insulating substrate 2, and heats the heating element 4 through the front-side intermediate electrode 8a and the back-side intermediate electrode 8b, which are excellent in thermal conductivity. heat is transmitted to the heating element drawer energizing portion 4c, and the fusible conductor 3 can be heated and fused (FIGS. 7(A) and 7(B)).
  • the heating element electrode 6 also serves as an external connection electrode that is connected to the electrode of the external circuit board, so the third external connection electrode 13 provided in the protection element 1 is not provided.
  • the glass layer 7 has partially different heat radiation characteristics, such as a portion in contact with the heating element 5 and the first and second extraction electrodes 15 and 16 and a portion not in contact.
  • the glass layer 7 has a lower melting point than the heating element 5, it softens when the heating element 5 generates heat. Therefore, the protective element 30 can dissipate the stress caused by the temperature difference in the glass layer 7, prevent the breakage of the glass layer 7 and the resulting insulation breakdown and breakage of the heating element 5, and the fusible conductor 3 It is possible to ensure the necessary and sufficient heating time of the heating element 5 to melt off the .
  • the glass layer 7 may have a lower melting point than the heating temperature of the heating element 5.
  • the melting point of the glass layer 7 may be 600° C. or less.
  • the melting point of the glass layer 7 is preferably higher than the temperature during reflow mounting of the protective element 1.
  • the melting point of the glass layer 7 may be 300° C. or higher.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Manufacturing & Machinery (AREA)
  • Fuses (AREA)
  • Protection Of Static Devices (AREA)
  • Secondary Cells (AREA)
  • Battery Mounting, Suspending (AREA)

Abstract

La présente invention concerne un élément de protection qui est capable de bloquer de manière sûre et rapide un trajet de courant sans provoquer de rupture d'une couche isolante ou d'un élément chauffant.　Cet élément de protection comprend un substrat isolant (2), un conducteur fusible (3) qui est disposé sur le substrat isolant (2) et supporté par celui-ci, une pluralité de parties de transport de courant (4) qui sont connectées au conducteur fusible (3), un élément chauffant (5) qui est disposé sur le substrat isolant (2) et qui génère de la chaleur lorsqu'un courant passe à travers celui-ci, une électrode d'élément chauffant (6) qui est reliée à l'élément chauffant (5) et sert de borne d'alimentation pour l'élément chauffant (5), et une couche de verre (7) qui recouvre l'élément chauffant (5) ; et la couche de verre (7) a un point de fusion qui est inférieur au point de fusion de l'élément chauffant (5).
PCT/JP2022/007434 2021-02-24 2022-02-23 Élément de protection et bloc-batterie WO2022181652A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2021-028002 2021-02-24
JP2021028002A JP2022129313A (ja) 2021-02-24 2021-02-24 保護素子及びバッテリパック

Publications (1)

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WO2022181652A1 true WO2022181652A1 (fr) 2022-09-01

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JP (1) JP2022129313A (fr)
TW (1) TW202303649A (fr)
WO (1) WO2022181652A1 (fr)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001334394A (ja) * 2000-05-23 2001-12-04 Nec Schott Components Corp フラックス、フラックス付き低融点合金およびそれを用いた保護素子
JP2009105263A (ja) * 2007-10-24 2009-05-14 Panasonic Corp 抵抗体ペースト及びその製造方法
JP2013229295A (ja) * 2012-03-29 2013-11-07 Dexerials Corp 保護素子
WO2014109097A1 (fr) * 2013-01-11 2014-07-17 株式会社村田製作所 Fusible

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001334394A (ja) * 2000-05-23 2001-12-04 Nec Schott Components Corp フラックス、フラックス付き低融点合金およびそれを用いた保護素子
JP2009105263A (ja) * 2007-10-24 2009-05-14 Panasonic Corp 抵抗体ペースト及びその製造方法
JP2013229295A (ja) * 2012-03-29 2013-11-07 Dexerials Corp 保護素子
WO2014109097A1 (fr) * 2013-01-11 2014-07-17 株式会社村田製作所 Fusible

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JP2022129313A (ja) 2022-09-05

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