WO2020119897A1 - Cap assembly for a battery cell having electronic safety functionality - Google Patents

Cap assembly for a battery cell having electronic safety functionality Download PDF

Info

Publication number
WO2020119897A1
WO2020119897A1 PCT/EP2018/084392 EP2018084392W WO2020119897A1 WO 2020119897 A1 WO2020119897 A1 WO 2020119897A1 EP 2018084392 W EP2018084392 W EP 2018084392W WO 2020119897 A1 WO2020119897 A1 WO 2020119897A1
Authority
WO
WIPO (PCT)
Prior art keywords
terminal
battery cell
cap assembly
cap
plate
Prior art date
Application number
PCT/EP2018/084392
Other languages
French (fr)
Inventor
Azad Darbandi
Lingbo Zhu
Original Assignee
Bayerische Motoren Werke Aktiengesellschaft
Contemporary Amperex Technology Co., Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Bayerische Motoren Werke Aktiengesellschaft, Contemporary Amperex Technology Co., Limited filed Critical Bayerische Motoren Werke Aktiengesellschaft
Priority to EP18830161.8A priority Critical patent/EP3894262A1/en
Priority to PCT/EP2018/084392 priority patent/WO2020119897A1/en
Publication of WO2020119897A1 publication Critical patent/WO2020119897A1/en

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L3/00—Electric devices on electrically-propelled vehicles for safety purposes; Monitoring operating variables, e.g. speed, deceleration or energy consumption
    • B60L3/0023—Detecting, eliminating, remedying or compensating for drive train abnormalities, e.g. failures within the drive train
    • B60L3/0046—Detecting, eliminating, remedying or compensating for drive train abnormalities, e.g. failures within the drive train relating to electric energy storage systems, e.g. batteries or capacitors
    • 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 of a single cell or a single battery
    • 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
    • H01M50/176—Arrangements of electric connectors penetrating the casing adapted for the shape of the cells for prismatic or rectangular cells
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L3/00—Electric devices on electrically-propelled vehicles for safety purposes; Monitoring operating variables, e.g. speed, deceleration or energy consumption
    • B60L3/04—Cutting off the power supply under fault conditions
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L50/00—Electric propulsion with power supplied within the vehicle
    • B60L50/50—Electric propulsion with power supplied within the vehicle using propulsion power supplied by batteries or fuel cells
    • B60L50/60—Electric propulsion with power supplied within the vehicle using propulsion power supplied by batteries or fuel cells using power supplied by batteries
    • B60L50/64—Constructional details of batteries specially adapted for electric vehicles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L58/00—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
    • B60L58/10—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries
    • B60L58/12—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries responding to state of charge [SoC]
    • B60L58/15—Preventing overcharging
    • 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
    • H01M10/04—Construction or manufacture in general
    • H01M10/0431—Cells with wound or folded electrodes
    • 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 of a single cell or a single battery
    • H01M50/147—Lids or covers
    • H01M50/155—Lids or covers characterised by the 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 of a single cell or a single battery
    • H01M50/147—Lids or covers
    • H01M50/166—Lids or covers characterised by the methods of assembling casings with lids
    • H01M50/169—Lids or covers characterised by the methods of assembling casings with lids by welding, brazing or soldering
    • 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
    • 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
    • H01M50/564—Terminals characterised by their manufacturing process
    • 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
    • H01M50/572—Means for preventing undesired use or discharge
    • H01M50/574—Devices or arrangements for the interruption of current
    • H01M50/581—Devices or arrangements for the interruption of current in response to temperature
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2200/00—Safety devices for primary or secondary batteries
    • H01M2200/10—Temperature sensitive devices
    • H01M2200/103—Fuse
    • 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 of a single cell or a single battery
    • H01M50/147—Lids or covers
    • H01M50/148—Lids or covers characterised by their shape
    • H01M50/15—Lids or covers characterised by their shape for prismatic or rectangular cells
    • 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
    • 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
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/70—Energy storage systems for electromobility, e.g. batteries

Definitions

  • Cap assembly for a battery cell having electronic safety functionality
  • the disclosure relates to a cap assembly having electronic safety functionality to prevent an overcharge state of a battery cell.
  • the charging state of a battery cell is an essential
  • a low charging state of the battery cell may cause a malfunction of the electric motor or may at least be responsible for the electric motor not reaching the maximum possible performance.
  • overcharging of a battery cell leads to a release of gases inside the battery cell and to the outside atmosphere as well as to a rise in battery temperature so that the battery cell can be damaged.
  • the battery cell before being used, the battery cell usually has to pass an overcharge homologation test (GB/T) .
  • G/T overcharge homologation test
  • Mechanical devices which will be activated by cell internal gas pressure may be used to detect an overcharge state of the battery.
  • Those mechanical devices are provided in a cap assembly of the battery cell. They may comprises a movable membrane which is sensitive to the cell internal gas
  • the rise of the cell internal gas pressure effects a movement of the membrane to cause a short-circuit between positive and negative terminals of the battery.
  • the high current flow caused due to the short-circuit of the battery poles can be detected and used to interrupt an electrical connection between internal electrodes of the battery cell and external terminals.
  • An embodiment of a cap assembly for a battery cell having electronic safety functionality to detect and prevent an overcharge state of the battery cell is specified in claim 1.
  • the cap assembly comprises a cap plate being electro- conductive, a first terminal to be coupled to a first
  • the first terminal has a first voltage potential, when the first
  • the second terminal has a second voltage potential, when the second terminal is coupled to the second electrode of the battery cell.
  • the cap assembly further comprises an electrical device having a variable electrical conductivity.
  • the first terminal is coupled to the cap plate by the electrical device.
  • the second terminal is electro-conductively connected to the cap 5 plate.
  • the electrical device is configured such that an
  • the assembly may be configured to passively monitor the voltage of the battery cell, for example the voltage between the positive terminal and the negative terminal of the battery cell.
  • the first terminal is electrically coupled to the cap5 plate.
  • electrically coupled means that the
  • the electrical/electronic device may have a highly resistive state or even an insulating state or may have a low resistive state.
  • the first terminal is :0 highly resistively connected to the cap plate or is
  • the first terminal may be low resistively connected to the cap plate.
  • the cap assembly comprises a connection plate being arranged above the cap plate and being electro-conductively connected to the first terminal.
  • the electrical device is arranged 10 between the connection plate and the cap plate.
  • the first terminal comprises a contacting portion to contact the battery cell and a connecting portion to contact the connection plate.
  • the electrical/electronic device gets activated, i.e. is 5 operated, in a low resistive/highly conductive state, when it is detected by the electrical/electronic device that the voltage of the battery cell exceeds a certain voltage
  • the electrical/electronic device will change a previous high resistive or insulating0 state to a highly conductive/low resistive state.
  • the cap assembly is embodied such that the high current caused by the short-circuit between the terminals of the battery cell leads to an interruption of the connecting portion of the first terminal, i.e. the connector between the :0 connection plate and the battery cell (jelly-roll of the
  • the cell in the overcharge state of the battery cell, the cell becomes isolated from the connection plate and thus from a battery system.
  • the connecting portion of the first terminal may be
  • the high current caused by the short- circuit between the first and second terminal of the battery cell leads to a melting of the fuse so that the battery cell and, in particular, the jelly-roll of the battery cell is 10 isolated from the (outer) connection plate.
  • a power battery comprising the cap assembly as specified above is disclosed in claim 14.
  • the power battery comprises a battery cell and a case.
  • the cap assembly is sealed on top of the case to form an
  • the battery cell is provided in the 5 accommodating space.
  • the electrical/electronic device included in the cap assembly provides a high reliability of the battery cell and the whole power battery system.
  • the proposed solution detects the excess of a voltage threshold value to release the overcharge safety action, i.e. to interrupt an electrical path between the connection plate of the cap assembly and an5 electrode of the battery cell.
  • FIG. 1 shows an exploded view of a first embodiment of a cap assembly for a battery cell having electronic safety functionality
  • Figure 2A shows a cross-sectional view of the first
  • Figure 2B shows an enlarged view of a connecting portion of a terminal of the first embodiment of a cap assembly for a :5 battery cell having electronic safety functionality
  • Figure 3 shows an exploded view of a second embodiment of a cap assembly for a battery cell having electronic safety functionality
  • Figure 4A shows a top view onto the second embodiment of a cap assembly for a battery cell having electronic safety functionality
  • Figure 4B shows a cross-sectional view of the second embodiment of a cap assembly for a battery cell having electronic safety functionality
  • Figure 4C shows another cross-sectional view of the second embodiment of a cap assembly for a battery cell having electronic safety functionality
  • Figure 5A shows a perspective view of a power battery to be sealed by a cap assembly having electronic safety
  • Figure 5B shows a perspective view of a battery cell of a5 power battery.
  • Figures 1 and 3 show different embodiments of a cap assembly 10, 20 for a battery cell having electronic safety
  • the cap assembly 10, 20 comprises a cap plate 100 being electro-conductive, a first terminal 110a and a second terminal 110b, wherein both terminals 110a, 110b are configured to be coupled to different potentials of the
  • the first terminal 110a is configured to be coupled to a first electrode of the battery cell
  • the second terminal 110b is configured to be coupled to a second 10 electrode of the battery cell.
  • the first terminal 110a has a first voltage potential, when the first terminal 110a is coupled to the first electronic of the battery cell.
  • the second terminal 110b has a second voltage potential, when the second terminal is coupled to the second electronic of the battery cell.
  • the first voltage potential can be a negative potential and the second voltage potential can be a positive potential. That means, when the cap assembly is connected 5 with the battery cell, the first terminal can be embodied as the negative terminal and the second terminal can be embodied as the positive terminal.
  • the cap assembly 10, 20 further comprises an electrical/0 electronic device 120 having a variable electrical
  • the first terminal 110a is coupled to the cap plate 100 by the electrical/electronic device 120, as
  • the second terminal 110b is5 permanently electro-conductively connected to the cap plate 100.
  • the electrical device 120 is configured such that an electrical conductivity of the electrical device 120 is dependent on a voltage between the first terminal 110a and the second terminal 110b of the cap assembly.
  • the electrical/electronic device 120 is configured to have a first resistance, when the voltage between the first terminal 110a and the second terminal 110b is above a voltage
  • the electrical device 120 is further
  • the first resistance is lower than the second resistance.
  • the electrical/electronic device can be embodied such that the electrical/electronic device has a low resistive
  • the electrical/electronic device can be further embodied such that the electrical/electronic device has a high resistive/low conductive state or even an 5 insulating state, when the voltage between the first terminal 110a and the second terminal 110b is below the voltage threshold value.
  • the cap assembly 10, 20 or the electrical/0 electronic device 120 may be configured such that the voltage threshold value is in a range between 4.0 V and 5.0 V and is preferably 4.5 V.
  • the5 electrical/electronic device 120 may be embodied such that the first terminal 110a is electrically insulated from the cap plate 100, when the electrical/electronic device 120 has the second, i.e. the higher, resistance.
  • the electrical/ electronic device 120 may further be embodied such that the :0 first terminal 110a is electro-conductively connected to the cap plate 100 in response to the detection of a battery voltage, i.e. a voltage between the first terminal 110a and the second terminal 110b, above the voltage threshold value, for example a voltage above 4.0 V and preferably above 4.5 V. :5
  • the electrical/electronic device 120 may be configured as a voltage induction element to detect/monitor the battery voltage or the voltage between the first terminal 110a and 10 the second terminal 110b.
  • the electrical/electronic device 120 may be configured as a variable resistor or a semiconductor device having the first resistance, when the battery voltage/voltage between the first terminal 110a and the second terminal 110b is above the voltage threshold value and having the second resistance, when the battery voltage/ voltage between the first terminal 110a and the second
  • electrical/electronic device 120 may comprises at least one diode .
  • connection plate 130 is arranged above the cap plate 100.
  • the connection plate 130 is electro-conductively connected to the first terminal 110a.
  • the electrical/electronic device 120 is arranged between the connection plate 130 and the cap plate 100.
  • the first connection plate 130 has a lower surface 131, and the cap plate 100 has an upper surface :0 101.
  • the first connection plate 130 is arranged above the cap plate 100 such that a portion 131a of the lower surface 131 of the first connection plate 130 faces a portion 101a of the upper surface 101 of the cap plate 100.
  • connection plate 130 has a groove 132.
  • the portion 131a of the lower surface 131 of the first connection plate 130 is formed as the bottom surface of the groove 132.
  • portion 101a of the upper surface 101 of the 10 cap plate 100 has a groove 102.
  • the portion 101a of the upper surface 101 of the cap plate 100 is formed as the bottom surface of the groove 102.
  • the electrical/electronic device 120 is embedded in the groove 132 of the portion 131a of the lower surface 131 of the first connection plate 130.
  • the electrical/electronic device 120 is embedded in 5 the groove 102 of the portion 101a of the upper surface 101 of the cap plate 100.
  • the cap assembly 10 comprises a first insulating component 140 being arranged between the negative connection plate 1300 and the cap plate 100.
  • the first insulating component 140 is embodied such that a remaining portion 131b of the lower surface 131 of the first connection plate 130 is electrically isolated from the cap plate 100 by the first insulating component 140.
  • the insulating component 140 comprises a hole5 141 through which the electrical/electronic device 120
  • the cap plate 100 comprises a through-hole 103 which
  • the first terminal 110a comprises a contacting portion 111a to contact the battery cell, in particular the first electrode of the battery cell.
  • the first terminal 110a further comprises a connecting portion 112a to contact the connection plate 130.
  • portion 111a extends through the hole 103 of the cap plate 100 to the connection plate 130.
  • the cap assembly 10 further comprises an insulating component 10 170a having a through-hole 171 and a sealing element 150a.
  • the connecting portion 112a extends through a hole 151 in the sealing element 150a and the through-hole 171 of the insulating component 170a and the through-hole 103 of the cap plate 100 and a through-hole 142 of the insulating component 140 to the connection plate 130.
  • the upper face of the connecting portion 112a ends in a contacting hole 137 of the connection 5 plate 130.
  • the cap assembly 10 further comprises a connection plate 160 being arranged above the cap plate 100 and being electro- conductively connected to the second terminal 110b.
  • connection plate 160 is electro-conductively connected to the cap plate 100.
  • the second terminal 110b comprises a
  • the connecting portion 112b extends through a through-hole 151 of a sealing element 150b and a through-hole 171 of an insulating component 170b and a through-hole 104 of the cap plate 100 and ends in a hole 161 of the connection plate 160.
  • terminal 110b is electrically connected to the connection plate 160.
  • cap assembly 10 According to a possible embodiment of the cap assembly 10,
  • the connecting portion 112a of the first terminal 110a is configured as a fuse 113, as shown in Figure 2B.
  • the fuse 113 is configured as an aperture provided in the
  • connection portion 112a of the first terminal 110a The
  • connection portion 112a may be configured as a flat
  • the cap assembly 10 is described in the following .
  • the first terminal 110a is electrically connected to the connection plate 130, and the connection plate 130 is (nearly) electrically isolated from the cap0 plate 100 by the highly resistive state/insulating state of the electrical/electronic device 120.
  • the voltage between the first terminal llOa/the connection plate 130 and the second terminal llOb/the connection plate 160 exceeds the voltage threshold value, for example a value of about 4.0 V :0 or preferably of about 4.5 V, the electrical conductivity of the electrical/electronic device 120 increases.
  • conductive state of the electrical/electronic device changes from the highly resistive state/insulating state to the low resistive state so that a short-circuit current flows between :5 the first terminal 110a and the second terminal 110b via the cap plate 100.
  • connecting portion 112a of the first terminal 110a melts and the current flow is interrupted.
  • the battery cell thus becomes isolated from the battery system.
  • the connecting portion 112a with the melting fuse 113 has a specific ampacity. This configuration suits specially for cases in which a specific fuse characteristic (ampacity) is required on cell from the energy storage/battery system.
  • the first terminal 110a comprises a contacting portion 111a to0 contact the battery cell, in particular a first electrode of the battery cell.
  • the first terminal 110a further comprises a connecting portion 112a to contact a first connection plate 130.
  • the contacting portion 111a is formed as a bent conductive structure, for example a C-shaped bent structure, wherein the connecting portion 112a is disposed at one side of the upper portion of the contacting portion 111a.
  • the connecting portion 112a may be configured :0 as a flat conductor, for example a conductive sheet, which is arranged at one side of the upper part of the contacting portion 111a.
  • the connecting plate 130 has a portion 134 having a different :5 cross-sectional area from another portion 135 of the
  • connection plate 130 may have a groove 136 which is provided in a central section of the connection plate 130.
  • the electrical/electronic device 120 is disposed between the connection plate 130 and the cap plate 100.
  • the electrical device 120 may comprises at least one diode. According to a possible embodiment, the
  • electrical/electronic device 120 may comprises at least two diodes being arranged around the first terminal 110a or the connecting portion 112a of the first terminal.
  • 5 electrical/electronic device 120 comprises a through-hole
  • the first terminal 110a In the assembled state of the cap assembly 20, the first terminal 110a, particularly the connecting portion 112a of the first terminal 110a, passes through the through-hole 121 of the electrical/electronic device 120.
  • the connecting portion 112a of the first terminal 110a protrudes from the contacting portion 111a and extends through a through-hole 171 of an insulating component 170a, a through-5 hole 103 of the cap plate 100, the through-hole 121 of the electrical/electronic device 120 and the groove 136 of the connection plate 130.
  • the embodiment of the cap plate 20 further comprises the :0 second terminal 110b, the sealing component 150b, the
  • insulating component 170b and the connection plate 160 which are similar to the components described with reference to Figure 1 for the cap assembly 10.
  • the terminal 110b is electrically connected to the cap plate 100.
  • a normal operation state of a battery cell i.e. a 10 state in which the battery cell is charged below the
  • the connecting plate 130 is (nearly) electrically isolated from the cap plate 100 by the highly resistive state/insulating state of the electrical/electronic device 120.
  • connection plate 130 and the second terminal 11 Ob/connection plate 160 grows up.
  • the voltage threshold value for example exceeds a value of 4.0 V and preferably a value of 4.5 V
  • the conductive state of the0 electrical/electronic device 120 changes from the highly
  • connection plate 130 is electro-conductively connected to the cap plate 100 by a low resistive state of the
  • a short-circuit current occurs between the first terminal 110a and the second terminal 110b via the cap plate 100.
  • the high short-circuit current causes a melting of :0 the connection portion 112a of the first terminal 110a so
  • the second embodiment of of the cap assembly 20 is preferred.
  • connection portion 112a of the second embodiment of the cap assembly 20 has higher ampacity in order to enable melting of the connection portion 112a during activation of electronic device 120, i.e. during the low resistive state of the electronic device 120, in comparison to the connection 10 portion 112a of the first embodiment of the cap assembly 10, the electronic device 120 is located such that the electronic device 120 surrounds the connection portion 112a.
  • the heat generated during the current flow through the connection portion 112a of the first terminal 110a in the low resistive state of the electronic device 120 facilitate a faster meltdown of the connection portion 112a.
  • connection portion 112a of the second 5 embodiment of the cap assembly 20 does not comprise a tapered region, the ohmic losses in the normal operation state of the battery cell are lower for the second embodiment of the cap assembly 20 than for the first embodiment of the cap assembly 10.
  • the cap assembly 10, 20 having electrical/electronic safety functionality may be used to seal a case of a power battery.
  • Figure 5A shows a power battery 1 comprising a battery cell 30 and a case 40 in which the battery cell 30 is arranged.5
  • the cap assembly 10, 20, not shown in Figure 5A, is sealed on top of the case 40 to form an accommodating space 50.
  • the battery cell 30 is provided in the accommodating space 50 of the power battery.
  • the battery cell 30 may be formed as a jelly-roll with a jelly-roll termination adhesive 31.
  • Figure 5B illustrates the power battery 1 comprising the battery cell 30 and the cap assembly 10, 20.
  • Figure 5B illustrates the interior of the battery cell 30.
  • connection plate 130 and the connection plate 160 are :5 formed as outer connection elements 131 and 161.
  • the jelly- roll of the battery cell 30 comprises a negative electrode 60 with a current collector 61, a positive electrode 80 with a current collector 81, and a separator 70 positioned between the negative electrode 60 and the positive electrode 80.
  • the 10 negative electrode 60 is connected to a tab 91.
  • the positive electrode 80 of the battery cell 30 is electrically connected to a tab 92.
  • the first terminal 110a of the cap assembly 10, 20 is electrically coupled to the negative electrode 60 of the battery cell 30 by the tab 91.
  • the second terminal 110b of the cap assembly 10, 20 is electrically coupled to the positive electrode 80 of the battery cell 30 by the tab 92.

Abstract

A cap assembly (10, 20) for a battery cell (30) having electronic safety functionality comprises a cap plate (100) being electro-conductive,a first terminal (110a) to be coupled to a first electrode (60) of the battery cell (30), and a second terminal (110b) to be coupled to a second electrode (80) of the battery cell (30). The cap assembly (10, 20) further comprises an electrical device (120) having a variable electrical conductivity. The first terminal (110a) is coupled to the cap plate (100) by the electrical device (120),and the second terminal (110b) is electro-conductively connected to the cap plate (100). The electrical device (120) is configured such that an electrical conductivity of the electrical device (120) is dependent on a voltage between the first terminal (110a) and the second terminal (110b).

Description

Description
Cap assembly for a battery cell having electronic safety functionality
The disclosure relates to a cap assembly having electronic safety functionality to prevent an overcharge state of a battery cell.
The charging state of a battery cell is an essential
parameter to ensure a proper functionality of the battery cell, for example to provide enough energy for operating an electric motor of an electric vehicle. A low charging state of the battery cell may cause a malfunction of the electric motor or may at least be responsible for the electric motor not reaching the maximum possible performance. On the other hand, overcharging of a battery cell leads to a release of gases inside the battery cell and to the outside atmosphere as well as to a rise in battery temperature so that the battery cell can be damaged.
Therefore, before being used, the battery cell usually has to pass an overcharge homologation test (GB/T) . Mechanical devices, which will be activated by cell internal gas pressure may be used to detect an overcharge state of the battery. Those mechanical devices are provided in a cap assembly of the battery cell. They may comprises a movable membrane which is sensitive to the cell internal gas
pressure. The rise of the cell internal gas pressure effects a movement of the membrane to cause a short-circuit between positive and negative terminals of the battery. The high current flow caused due to the short-circuit of the battery poles can be detected and used to interrupt an electrical connection between internal electrodes of the battery cell and external terminals.
Mechanical devices, for example the above-mentioned membrane, 5 to act on the cell internal gas pressure and thereby detect an overcharge state of the battery cell show limited
reliability due to degradation and fatigue and often have a low lifetime. Furthermore, the susceptibility of mechanical devices to detect an overcharge state of a battery cell
0 depends on various factors such as ampacity, contamination etc.. Another disadvantage is that adoption of mechanical devices affect the cell functional reliability over service life . 5 There is a desire to provide a cap assembly for a battery
cell having electronic safety functionality to replace mechanical devices in a cap assembly and to reliably detect and prevent an overcharge state of the battery cell in due time, before the battery cell is damaged.
:0
An embodiment of a cap assembly for a battery cell having electronic safety functionality to detect and prevent an overcharge state of the battery cell is specified in claim 1.
:5 The cap assembly comprises a cap plate being electro- conductive, a first terminal to be coupled to a first
electrode of the battery cell and a second terminal to be coupled to a second electrode of the battery cell. The first terminal has a first voltage potential, when the first
10 terminal is coupled to the first electrode of the battery
cell. The second terminal has a second voltage potential, when the second terminal is coupled to the second electrode of the battery cell. The cap assembly further comprises an electrical device having a variable electrical conductivity. The first terminal is coupled to the cap plate by the electrical device. The second terminal is electro-conductively connected to the cap 5 plate. The electrical device is configured such that an
electrical conductivity of the electrical device is dependent on a voltage between the first terminal and the second terminal . 0 The electrical or electronic device included in the cap
assembly may be configured to passively monitor the voltage of the battery cell, for example the voltage between the positive terminal and the negative terminal of the battery cell. The first terminal is electrically coupled to the cap5 plate. The term "electrically coupled" means that the
electrical/electronic device may have a highly resistive state or even an insulating state or may have a low resistive state. When the electrical/electronic device is operated in the high resistive or insulating state, the first terminal is :0 highly resistively connected to the cap plate or is
electrically isolated from the cap plate. On the other hand, when the electrical/electronic device is operated in the low resistive state, the first terminal may be low resistively connected to the cap plate.
:5
According to a possible embodiment of the cap assembly, the cap assembly comprises a connection plate being arranged above the cap plate and being electro-conductively connected to the first terminal. The electrical device is arranged 10 between the connection plate and the cap plate.
According to another embodiment of the cap assembly, the first terminal comprises a contacting portion to contact the battery cell and a connecting portion to contact the connection plate.
The electrical/electronic device gets activated, i.e. is 5 operated, in a low resistive/highly conductive state, when it is detected by the electrical/electronic device that the voltage of the battery cell exceeds a certain voltage
threshold value. In this case, the electrical/electronic device will change a previous high resistive or insulating0 state to a highly conductive/low resistive state. As a
consequence, a short-circuit is provided between the first terminal and the second terminal of the battery cell, and a high current passes through the battery cell for a fraction of seconds.
5
The cap assembly is embodied such that the high current caused by the short-circuit between the terminals of the battery cell leads to an interruption of the connecting portion of the first terminal, i.e. the connector between the :0 connection plate and the battery cell (jelly-roll of the
battery cell) . Therefore, in the overcharge state of the battery cell, the cell becomes isolated from the connection plate and thus from a battery system.
:5 The connecting portion of the first terminal may be
configured as a fuse. The high current caused by the short- circuit between the first and second terminal of the battery cell leads to a melting of the fuse so that the battery cell and, in particular, the jelly-roll of the battery cell is 10 isolated from the (outer) connection plate.
A power battery comprising the cap assembly as specified above is disclosed in claim 14. The power battery comprises a battery cell and a case. The cap assembly is sealed on top of the case to form an
accommodating space. The battery cell is provided in the 5 accommodating space.
The electrical/electronic device included in the cap assembly provides a high reliability of the battery cell and the whole power battery system. In contrast to a mechanical device to0 detect an overcharge state of the battery cell by detecting a gas pressure in the battery cell, the proposed solution detects the excess of a voltage threshold value to release the overcharge safety action, i.e. to interrupt an electrical path between the connection plate of the cap assembly and an5 electrode of the battery cell.
In contrast to an embodiment of a cap assembly using
mechanical devices to provide safety functionality for a battery cell, a normal gas generation in the battery cell :0 over its lifetime will not lead to an undesired activation of the electrical/electronic safety device. This is very
desirable for prospective generations of high energy density battery cells.
:5 Additional features and advantages are set forth in the
detailed description that follows and in part will be readily apparent to those skilled in the art from the description or recognized by practising the embodiments as described in the written description and claims hereof, as well as the
10 appended drawings. It is to be understood that both the
foregoing general description and the following detailed description are merely exemplary, and are intended to provide an overview or framework to understand the nature and character of the claims.
Brief Description of the Drawings
5
The accompanying drawings are included to provide further understanding, and are incorporated in and constitute a part of the specification. The drawings illustrate several embodiments, and together with the detailed description serve0 to explain principles and operation of the various
embodiments. As such, the disclosure will become more fully understood from the following detailed description, taken in conjunction with the accompanying figures in which 5 Figure 1 shows an exploded view of a first embodiment of a cap assembly for a battery cell having electronic safety functionality;
Figure 2A shows a cross-sectional view of the first
:0 embodiment of a cap assembly for a battery cell having
electronic safety functionality;
Figure 2B shows an enlarged view of a connecting portion of a terminal of the first embodiment of a cap assembly for a :5 battery cell having electronic safety functionality;
Figure 3 shows an exploded view of a second embodiment of a cap assembly for a battery cell having electronic safety functionality;
10
Figure 4A shows a top view onto the second embodiment of a cap assembly for a battery cell having electronic safety functionality; Figure 4B shows a cross-sectional view of the second embodiment of a cap assembly for a battery cell having electronic safety functionality;
5
Figure 4C shows another cross-sectional view of the second embodiment of a cap assembly for a battery cell having electronic safety functionality; 0 Figure 5A shows a perspective view of a power battery to be sealed by a cap assembly having electronic safety
functionality; and
Figure 5B shows a perspective view of a battery cell of a5 power battery.
Figures 1 and 3 show different embodiments of a cap assembly 10, 20 for a battery cell having electronic safety
functionality by using an electrical/electronic device to :0 detect an overcharge state of a battery cell which is sealed by the cap assembly. The cap assembly 10, 20 comprises a cap plate 100 being electro-conductive, a first terminal 110a and a second terminal 110b, wherein both terminals 110a, 110b are configured to be coupled to different potentials of the
:5 battery cell.
In particular, the first terminal 110a is configured to be coupled to a first electrode of the battery cell, and the second terminal 110b is configured to be coupled to a second 10 electrode of the battery cell. The first terminal 110a has a first voltage potential, when the first terminal 110a is coupled to the first electronic of the battery cell. The second terminal 110b has a second voltage potential, when the second terminal is coupled to the second electronic of the battery cell. The first voltage potential can be a negative potential and the second voltage potential can be a positive potential. That means, when the cap assembly is connected 5 with the battery cell, the first terminal can be embodied as the negative terminal and the second terminal can be embodied as the positive terminal.
The cap assembly 10, 20 further comprises an electrical/0 electronic device 120 having a variable electrical
conductivity. The first terminal 110a is coupled to the cap plate 100 by the electrical/electronic device 120, as
illustrated in the cross-sectional view of the cap assembly 10, 20 in Figures 2A and 4B. The second terminal 110b is5 permanently electro-conductively connected to the cap plate 100. The electrical device 120 is configured such that an electrical conductivity of the electrical device 120 is dependent on a voltage between the first terminal 110a and the second terminal 110b of the cap assembly.
According to an embodiment of the cap assembly 10 and 20 the electrical/electronic device 120 is configured to have a first resistance, when the voltage between the first terminal 110a and the second terminal 110b is above a voltage
:5 threshold value. The electrical device 120 is further
configured to have a second resistance, when the voltage between the first terminal 110a and the second terminal 110b is below the voltage threshold value. The first resistance is lower than the second resistance.
10
The electrical/electronic device can be embodied such that the electrical/electronic device has a low resistive
state/highly conductive state, when the voltage between the first terminal 110a and the second terminal 110b is above the voltage threshold value. The electrical/electronic device can be further embodied such that the electrical/electronic device has a high resistive/low conductive state or even an 5 insulating state, when the voltage between the first terminal 110a and the second terminal 110b is below the voltage threshold value.
In particular, the cap assembly 10, 20 or the electrical/0 electronic device 120 may be configured such that the voltage threshold value is in a range between 4.0 V and 5.0 V and is preferably 4.5 V.
According to a possible embodiment of the cap assembly, the5 electrical/electronic device 120 may be embodied such that the first terminal 110a is electrically insulated from the cap plate 100, when the electrical/electronic device 120 has the second, i.e. the higher, resistance. The electrical/ electronic device 120 may further be embodied such that the :0 first terminal 110a is electro-conductively connected to the cap plate 100 in response to the detection of a battery voltage, i.e. a voltage between the first terminal 110a and the second terminal 110b, above the voltage threshold value, for example a voltage above 4.0 V and preferably above 4.5 V. :5
According to a possible embodiment of the cap assembly 10, 20 the electrical/electronic device 120 may be configured as a voltage induction element to detect/monitor the battery voltage or the voltage between the first terminal 110a and 10 the second terminal 110b. According to a possible embodiment of the cap assembly, the electrical/electronic device 120 may be configured as a variable resistor or a semiconductor device having the first resistance, when the battery voltage/voltage between the first terminal 110a and the second terminal 110b is above the voltage threshold value and having the second resistance, when the battery voltage/ voltage between the first terminal 110a and the second
5 terminal 110b is below the voltage threshold value. The
electrical/electronic device 120 may comprises at least one diode .
According to the embodiment of the cap assembly 10, 20, a0 connection plate 130 is arranged above the cap plate 100. The connection plate 130 is electro-conductively connected to the first terminal 110a. The electrical/electronic device 120 is arranged between the connection plate 130 and the cap plate 100.
5
Referring to the first embodiment of the cap plate 10 shown in an exploded view in Figure 1 and in cross-sectional views in Figures 2A and 2B, the first connection plate 130 has a lower surface 131, and the cap plate 100 has an upper surface :0 101. The first connection plate 130 is arranged above the cap plate 100 such that a portion 131a of the lower surface 131 of the first connection plate 130 faces a portion 101a of the upper surface 101 of the cap plate 100.
:5 The portion 131a of the lower surface 131 of the first
connection plate 130 has a groove 132. In particular, the portion 131a of the lower surface 131 of the first connection plate 130 is formed as the bottom surface of the groove 132. Furthermore, the portion 101a of the upper surface 101 of the 10 cap plate 100 has a groove 102. In particular, the portion 101a of the upper surface 101 of the cap plate 100 is formed as the bottom surface of the groove 102. As illustrated in Figure 2A the electrical/electronic device 120 is embedded in the groove 132 of the portion 131a of the lower surface 131 of the first connection plate 130.
Moreover, the electrical/electronic device 120 is embedded in 5 the groove 102 of the portion 101a of the upper surface 101 of the cap plate 100.
The cap assembly 10 comprises a first insulating component 140 being arranged between the negative connection plate 1300 and the cap plate 100. The first insulating component 140 is embodied such that a remaining portion 131b of the lower surface 131 of the first connection plate 130 is electrically isolated from the cap plate 100 by the first insulating component 140. The insulating component 140 comprises a hole5 141 through which the electrical/electronic device 120
passes .
According to a possible embodiment of the cap assembly 10, the cap plate 100 comprises a through-hole 103 which
:0 completely penetrates the cap plate 100. The first terminal 110a comprises a contacting portion 111a to contact the battery cell, in particular the first electrode of the battery cell. The first terminal 110a further comprises a connecting portion 112a to contact the connection plate 130.
:5 The connecting portion 112a protrudes from the contacting
portion 111a and extends through the hole 103 of the cap plate 100 to the connection plate 130.
The cap assembly 10 further comprises an insulating component 10 170a having a through-hole 171 and a sealing element 150a. In the assembled state of the cap assembly 10, the connecting portion 112a extends through a hole 151 in the sealing element 150a and the through-hole 171 of the insulating component 170a and the through-hole 103 of the cap plate 100 and a through-hole 142 of the insulating component 140 to the connection plate 130. The upper face of the connecting portion 112a ends in a contacting hole 137 of the connection 5 plate 130.
The cap assembly 10 further comprises a connection plate 160 being arranged above the cap plate 100 and being electro- conductively connected to the second terminal 110b. The
0 connection plate 160 is electro-conductively connected to the cap plate 100. The second terminal 110b comprises a
contacting portion 111b to contact the battery cell, in particular the second electrode of the battery cell, and a connecting portion 112b to contact the second connection5 plate 160. In particular, the connecting portion 112b extends through a through-hole 151 of a sealing element 150b and a through-hole 171 of an insulating component 170b and a through-hole 104 of the cap plate 100 and ends in a hole 161 of the connection plate 160. The second terminal 110b and,
:0 particularly the connecting portion 111b of the second
terminal 110b is electrically connected to the connection plate 160.
According to a possible embodiment of the cap assembly 10,
:5 the connecting portion 112a of the first terminal 110a is configured as a fuse 113, as shown in Figure 2B. According to the embodiment of the fuse 113 illustrated in Figure 2B, the fuse 113 is configured as an aperture provided in the
connection portion 112a of the first terminal 110a. The
10 connection portion 112a may be configured as a flat
conductor, for example as a flat sheet, wherein the fuse is embodied as a part of the flat conductor having a reduced width of the conductive path. The functionality of the cap assembly 10 is described in the following .
5 In a normal operation state of a battery cell, i.e. when the battery cell is not over-charged and rather charged to a predefined value, the first terminal 110a is electrically connected to the connection plate 130, and the connection plate 130 is (nearly) electrically isolated from the cap0 plate 100 by the highly resistive state/insulating state of the electrical/electronic device 120.
When the battery cell is charged to an overcharge state, the voltage between the first terminal 110a and the second
5 terminal 110b or the voltage between the connection plate 130 and the connection plate 160 increases. When the voltage between the first terminal llOa/the connection plate 130 and the second terminal llOb/the connection plate 160 exceeds the voltage threshold value, for example a value of about 4.0 V :0 or preferably of about 4.5 V, the electrical conductivity of the electrical/electronic device 120 increases. The
conductive state of the electrical/electronic device changes from the highly resistive state/insulating state to the low resistive state so that a short-circuit current flows between :5 the first terminal 110a and the second terminal 110b via the cap plate 100.
However, the high short-circuit current occurs only for a fraction of seconds until the fuse structure 113 of the
10 connecting portion 112a of the first terminal 110a melts and the current flow is interrupted. The battery cell thus becomes isolated from the battery system. The connecting portion 112a with the melting fuse 113 has a specific ampacity. This configuration suits specially for cases in which a specific fuse characteristic (ampacity) is required on cell from the energy storage/battery system.
5
According to the second embodiment of the cap assembly 20 illustrated in an exploded view in Figure 3 and in cross- sectional views in the following figures 4A, 4B and 4C,the first terminal 110a comprises a contacting portion 111a to0 contact the battery cell, in particular a first electrode of the battery cell. The first terminal 110a further comprises a connecting portion 112a to contact a first connection plate 130. 5 As shown in Figures 3 and 4C, the contacting portion 111a is formed as a bent conductive structure, for example a C-shaped bent structure, wherein the connecting portion 112a is disposed at one side of the upper portion of the contacting portion 111a. The connecting portion 112a may be configured :0 as a flat conductor, for example a conductive sheet, which is arranged at one side of the upper part of the contacting portion 111a.
The connecting plate 130 has a portion 134 having a different :5 cross-sectional area from another portion 135 of the
connecting plate 130 along the thickness of the cap assembly 20. In particular, the connection plate 130 may have a groove 136 which is provided in a central section of the connection plate 130.
10
As shown in Figure 3, the electrical/electronic device 120 is disposed between the connection plate 130 and the cap plate 100. The electrical device 120 may comprises at least one diode. According to a possible embodiment, the
electrical/electronic device 120 may comprises at least two diodes being arranged around the first terminal 110a or the connecting portion 112a of the first terminal. The
5 electrical/electronic device 120 comprises a through-hole
121. In the assembled state of the cap assembly 20, the first terminal 110a, particularly the connecting portion 112a of the first terminal 110a, passes through the through-hole 121 of the electrical/electronic device 120.
0
According to the embodiment of the cap assembly 20, the connecting portion 112a of the first terminal 110a protrudes from the contacting portion 111a and extends through a through-hole 171 of an insulating component 170a, a through-5 hole 103 of the cap plate 100, the through-hole 121 of the electrical/electronic device 120 and the groove 136 of the connection plate 130.
The embodiment of the cap plate 20 further comprises the :0 second terminal 110b, the sealing component 150b, the
insulating component 170b and the connection plate 160 which are similar to the components described with reference to Figure 1 for the cap assembly 10.
:5 In the following, the functionality of the cap assembly 20 is described .
The terminal 110b is electrically connected to the cap plate 100. In a normal operation state of a battery cell, i.e. a 10 state in which the battery cell is charged below the
overcharge state and rather has a well-predefined charging state, the connecting plate 130 is (nearly) electrically isolated from the cap plate 100 by the highly resistive state/insulating state of the electrical/electronic device 120.
On the other hand, in an overcharged state of the battery 5 cell, the voltage between the first terminal llOa/the
connection plate 130 and the second terminal 11 Ob/connection plate 160 grows up. When the voltage exceeds the voltage threshold value, for example exceeds a value of 4.0 V and preferably a value of 4.5 V, the conductive state of the0 electrical/electronic device 120 changes from the highly
resistive or insulating state to the low resistive state. Thus, in the overcharge state of the battery cell, the connection plate 130 is electro-conductively connected to the cap plate 100 by a low resistive state of the
5 electrical/electronic device 120.
As a consequence, a short-circuit current occurs between the first terminal 110a and the second terminal 110b via the cap plate 100. The high short-circuit current causes a melting of :0 the connection portion 112a of the first terminal 110a so
that the current flow is interrupted within a short time.
In case the cell is allowed to have no melting fuse the second embodiment of of the cap assembly 20 is preferred.
:5 Since the connection portion 112a of the second embodiment of the cap assembly 20 has higher ampacity in order to enable melting of the connection portion 112a during activation of electronic device 120, i.e. during the low resistive state of the electronic device 120, in comparison to the connection 10 portion 112a of the first embodiment of the cap assembly 10, the electronic device 120 is located such that the electronic device 120 surrounds the connection portion 112a. As a consequence, the heat generated during the current flow through the connection portion 112a of the first terminal 110a in the low resistive state of the electronic device 120 facilitate a faster meltdown of the connection portion 112a. Moreover, since the connection portion 112a of the second 5 embodiment of the cap assembly 20 does not comprise a tapered region, the ohmic losses in the normal operation state of the battery cell are lower for the second embodiment of the cap assembly 20 than for the first embodiment of the cap assembly 10.
0
The cap assembly 10, 20 having electrical/electronic safety functionality may be used to seal a case of a power battery. Figure 5A shows a power battery 1 comprising a battery cell 30 and a case 40 in which the battery cell 30 is arranged.5 The cap assembly 10, 20, not shown in Figure 5A, is sealed on top of the case 40 to form an accommodating space 50. The battery cell 30 is provided in the accommodating space 50 of the power battery. The battery cell 30 may be formed as a jelly-roll with a jelly-roll termination adhesive 31.
Figure 5B illustrates the power battery 1 comprising the battery cell 30 and the cap assembly 10, 20. In particular, Figure 5B illustrates the interior of the battery cell 30.
The connection plate 130 and the connection plate 160 are :5 formed as outer connection elements 131 and 161. The jelly- roll of the battery cell 30 comprises a negative electrode 60 with a current collector 61, a positive electrode 80 with a current collector 81, and a separator 70 positioned between the negative electrode 60 and the positive electrode 80. The 10 negative electrode 60 is connected to a tab 91. The positive electrode 80 of the battery cell 30 is electrically connected to a tab 92. In the completely assembled state of the power battery 1, i.e. when the battery cell 30 is sealed by the cap assembly 10, 20, the first terminal 110a of the cap assembly 10, 20 is electrically coupled to the negative electrode 60 of the battery cell 30 by the tab 91. The second terminal 110b of the cap assembly 10, 20 is electrically coupled to the positive electrode 80 of the battery cell 30 by the tab 92.
List of reference signs
1 power battery
10 first embodiment of cap assembly
5 20 second embodiment of cap assembly
30 battery cell
40 case
50 accommodating space
60 negative electrode
0 70 separator
80 positive electrode
91, 92 tab
100 cap plate
110a first terminal
5 110b second terminal
111 contacting portion
112 connecting portion
120 electrical/electronic device 130 connection plate
:0 140 insulating component
150 sealing component
170 insulating component

Claims

Claims
1. A cap assembly for a battery cell having electronic saftey functionality, comprising:
5 - a cap plate (100) being electro-conductive,
- a first terminal (110a) to be coupled to a first electrode (60) of the battery cell (30), the first terminal (110a) having a first voltage potential, when the first terminal (110a) is coupled to the first electrode (60) of the battery0 cell (30),
- a second terminal (110b) to be coupled to a second
electrode (80) of the battery cell (30), the second terminal (110b) having a second voltage potential, when the second terminal (110b) is coupled to the second electrode (80) of5 the battery cell (30),
- an electrical device (120) having a variable electrical conductivity,
- wherein the first terminal (110a) is coupled to the cap plate (100) by the electrical device (120),
:0 - wherein the second terminal (110b) is electro-conductively connected to the cap plate (100),
- wherein the electrical device (120) is configured such that an electrical conductivity of the electrical device (120) is dependent on a voltage between the first terminal (110a) and
:5 the second terminal (110b) .
2. The cap assembly of claim 1,
- wherein the electrical device (120) is configured to have a first resistance, when the voltage between the first terminal
10 (110a) and the second terminal (110b) is above a voltage
threshold value,
- wherein the electrical device (120) is configured to have a second resistance, when the voltage between the first terminal (110a) and the second terminal (110b) is below the voltage threshold value,
- wherein the first resistance is lower than the second resistance .
5
3. The cap assembly of claim 2,
wherein the voltage threshold value is in a range between
4.0 V and 5.0 V and is preferably 4.5 V. 0 4. The cap assembly of any of claims 1 to 3, comprising:
- a first connection plate (130) being arranged above the cap plate (100) and being electro-conductively connected to the first terminal (110a),
- wherein the electrical device (120) is arranged between the5 first connection plate (130) and the cap plate (100) .
5. The cap assembly of claim 4,
- wherein the first connection plate (130) has a lower surface (131) and the cap plate (100) has an upper surface
:0 (101), wherein the first connection plate (130) is arranged above the cap plate (100) such that a portion (131a) of the lower surface (131) of the first connection plate (130) faces a portion (101a) of the upper surface (101) of the cap plate (100) ,
:5 - wherein the portion (131a) of the lower surface (131) of the first connection plate (130) and the portion (101a) of the upper surface (101) of the cap plate (100) respectively has a groove (132, 102),
- wherein the electrical device (120) is embedded in the
10 groove (132) of the portion (131a) of the lower surface (131) of the first connection plate (130) and the groove (102) of the portion (101a) of the upper surface (101) of the cap plate (100) .
6. The cap assembly of any of the claims 1 to 5,
wherein the electrical device (120) comprises at least one diode .
5 7. The cap assembly of any of the claims 1 to 6,
wherein the electrical device (120) comprises at least two diodes being arranged around the first terminal (110a) .
8. The cap assembly of any of the claims 4 to 7,
0 - wherein the cap plate (100) comprises a hole (103),
- wherein the first terminal (110a) comprises a contacting portion (111a) to contact the battery cell (30) and a
connecting portion (112a) to contact the first connection plate (130), the connecting portion (112a) protruding from5 the contacting portion (111a) through the hole (103) of the cap plate (100) to the first connection plate (130),
- wherein the connecting portion (112a) of the first terminal (110a) is configured as a fuse (113) .
:0
9. The cap assembly of claim 8,
wherein the fuse (113) is configured as an aperture provided in the connection portion (111a) of the first terminal
(110a) .
:5 10. The cap assembly of any of the claims 1 to 4,
wherein the first connection plate (130) has a portion (134) having a different cross-sectional area from another portion (135) of the first connection plate (130) along the thickness of the cap assembly (20) .
10
11. The cap assembly of any of claims 1 to 3 or 10,
wherein the first connection plate (130) has a groove (136) .
12. The cap assembly of claim 11,
- wherein the electrical device (120) comprises a through- hole (121),
- wherein the first terminal (110a) passes through the
5 through-hole (121) .
13. The cap assembly of claim 12,
wherein the first terminal (110a) comprises a contacting portion (111a) to contact the battery cell (30) and a
0 connecting portion (112a) to contact the first connection
plate (130), the connecting portion (112a) protruding from the contacting portion (111a) through the through-hole (121) of the electrical device (120) and the groove (136) of the first connection plate (130).
5
14. A power battery, comprising:
- a cap assembly (10, 20) as claimed in one of the claims 1 to 13,
- a battery cell (30),
: 0 - a case (40),
- wherein the cap assembly (10, 20) is sealed on top of the case (40) to form an accommodating space (50),
- wherein the battery cell (30) is provided in the
accommodating space (50).
:5
15. The power battery of claim 14,
- wherein the battery cell (30) comprises a negative
electrode (60), a positive electrode (80) and a separator (70) positioned between the negative electrode (60) and the
10 positive electrode (80),
- wherein the first terminal (110a) of the cap assembly (10, 20) is electrically coupled to the negative electrode (60) of the battery cell (30) and the second terminal (110b) of the cap assembly (10, 20) is electrically coupled to the positive electrode (80) of the battery cell (30) .
PCT/EP2018/084392 2018-12-11 2018-12-11 Cap assembly for a battery cell having electronic safety functionality WO2020119897A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP18830161.8A EP3894262A1 (en) 2018-12-11 2018-12-11 Cap assembly for a battery cell having electronic safety functionality
PCT/EP2018/084392 WO2020119897A1 (en) 2018-12-11 2018-12-11 Cap assembly for a battery cell having electronic safety functionality

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/EP2018/084392 WO2020119897A1 (en) 2018-12-11 2018-12-11 Cap assembly for a battery cell having electronic safety functionality

Publications (1)

Publication Number Publication Date
WO2020119897A1 true WO2020119897A1 (en) 2020-06-18

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Country Link
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