WO2021169721A1 - 电池包及电动车 - Google Patents

电池包及电动车 Download PDF

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Publication number
WO2021169721A1
WO2021169721A1 PCT/CN2021/074132 CN2021074132W WO2021169721A1 WO 2021169721 A1 WO2021169721 A1 WO 2021169721A1 CN 2021074132 W CN2021074132 W CN 2021074132W WO 2021169721 A1 WO2021169721 A1 WO 2021169721A1
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WO
WIPO (PCT)
Prior art keywords
battery
pole
battery pack
string
vehicle
Prior art date
Application number
PCT/CN2021/074132
Other languages
English (en)
French (fr)
Inventor
孙华军
王高武
刘国雄
朱燕
Original Assignee
比亚迪股份有限公司
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 比亚迪股份有限公司 filed Critical 比亚迪股份有限公司
Priority to JP2022550910A priority Critical patent/JP2023516593A/ja
Priority to KR1020227032851A priority patent/KR20220144402A/ko
Priority to EP21759605.5A priority patent/EP4113729A1/en
Publication of WO2021169721A1 publication Critical patent/WO2021169721A1/zh
Priority to US17/892,609 priority patent/US20220393321A1/en

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    • 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
    • B60L3/0007—Measures or means for preventing or attenuating collisions
    • 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
    • H01M50/583—Devices or arrangements for the interruption of current in response to current, e.g. fuses
    • 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
    • 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
    • B60L3/0069—Detecting, eliminating, remedying or compensating for drive train abnormalities, e.g. failures within the drive train relating to the isolation, e.g. ground fault or leak current
    • 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
    • B60L3/0092—Electric devices on electrically-propelled vehicles for safety purposes; Monitoring operating variables, e.g. speed, deceleration or energy consumption with use of redundant elements for safety purposes
    • 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
    • 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
    • B60L50/66—Arrangements of batteries
    • 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
    • B60L58/18—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries of two or more battery modules
    • B60L58/21—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries of two or more battery modules having the same nominal voltage
    • 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
    • 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
    • H01M50/204—Racks, modules or packs for multiple batteries or multiple cells
    • H01M50/207—Racks, modules or packs for multiple batteries or multiple cells characterised by their shape
    • H01M50/209—Racks, modules or packs for multiple batteries or multiple cells characterised by their shape adapted for prismatic 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
    • H01M50/20—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders
    • H01M50/249—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders specially adapted for aircraft or vehicles, e.g. cars or trains
    • 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
    • H01M50/258—Modular batteries; Casings provided with means for assembling
    • 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
    • H01M50/298—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders characterised by the wiring of battery packs
    • 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
    • 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
    • H01M50/502—Interconnectors for connecting terminals of adjacent batteries; Interconnectors for connecting cells outside a battery casing
    • 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
    • H01M50/502—Interconnectors for connecting terminals of adjacent batteries; Interconnectors for connecting cells outside a battery casing
    • H01M50/509—Interconnectors for connecting terminals of adjacent batteries; Interconnectors for connecting cells outside a battery casing characterised by the type of connection, e.g. mixed connections
    • 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
    • H01M50/502—Interconnectors for connecting terminals of adjacent batteries; Interconnectors for connecting cells outside a battery casing
    • H01M50/509—Interconnectors for connecting terminals of adjacent batteries; Interconnectors for connecting cells outside a battery casing characterised by the type of connection, e.g. mixed connections
    • H01M50/51—Connection only in series
    • 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
    • H01M50/572—Means for preventing undesired use or discharge
    • 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
    • H01M50/584—Means for preventing undesired use or discharge for preventing incorrect connections inside or outside the batteries
    • H01M50/588—Means for preventing undesired use or discharge for preventing incorrect connections inside or outside the batteries outside the batteries, e.g. incorrect connections of terminals or busbars
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60Y—INDEXING SCHEME RELATING TO ASPECTS CROSS-CUTTING VEHICLE TECHNOLOGY
    • B60Y2200/00—Type of vehicle
    • B60Y2200/90—Vehicles comprising electric prime movers
    • B60Y2200/91—Electric vehicles
    • 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
    • H01M2220/00—Batteries for particular applications
    • H01M2220/20—Batteries in motive systems, e.g. vehicle, ship, plane
    • 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

  • This application relates to the technical field of vehicle manufacturing, in particular to a battery pack and an electric vehicle.
  • the battery pack In electric vehicles, limited by the space of the electric vehicle, the battery pack is usually fixed on the bottom of the vehicle, that is, on the chassis of the vehicle. However, because the bottom of the vehicle is close to the ground, the battery pack installed at the bottom of the vehicle is extremely susceptible to impact during the driving process, which causes the single battery in the battery pack to easily produce a short circuit, especially when the vehicle is driving. The impact action on the bottom usually continues from the front to the rear, which will cause a short circuit of a string of single cells in the battery pack.
  • battery packs As the power source of electric vehicles, battery packs have a high energy density. High voltage and high energy density also mean high danger. When a string of single cells in the battery pack is short-circuited, if there is a string between the batteries High voltage will cause the battery pack to instantaneously produce high-voltage breakdown or high-voltage short circuit, making the battery pack prone to fire and explosion, and also prone to arcing, which poses a threat to the life and safety of drivers and passengers.
  • the present application aims to solve at least one of the technical problems existing in the prior art. For this reason, the present application proposes a battery pack and an electric vehicle, which can relatively reduce the voltage generated by the battery pack when the battery string is short-circuited, which is beneficial to prevent the battery pack from generating high voltage breakdown or high voltage short circuit, and improve the safety of the battery pack.
  • This application further proposes an electric vehicle.
  • the present application provides a battery pack for providing electric energy for a vehicle, comprising at least one battery unit, the battery unit comprising at least one battery string, the battery string containing one or at least two single cells, The voltage difference between the two ends of the battery string is less than or equal to 60V; when the battery string contains at least two single cells, the single cells in the battery string are arranged in sequence along a first direction, and the first direction is aligned with The direction from the rear of the vehicle to the front of the vehicle is parallel.
  • the voltage difference between the two ends of the battery string is less than or equal to 45V.
  • the voltage difference between the two ends of the battery string is 20-40V.
  • the battery unit includes a plurality of the battery strings, and the plurality of battery strings are sequentially arranged along a second direction, and the second direction is the width direction of the vehicle.
  • the battery strings are connected in series and/or in parallel.
  • the single cells in the battery string are connected in series.
  • the length of the single battery extends along the first direction.
  • the single cell includes a first pole and a second pole, and the single cell has two opposite first surfaces along a first direction; the first pole and The second poles are located on the same first surface of the single battery, or are located on the two first surfaces of the single battery respectively.
  • the single battery includes a first pole and a second pole, the single battery has a second surface facing the top of the vehicle, the first pole and the second pole Located on the second surface.
  • the battery cells there are multiple battery cells, and the battery cells are connected in series.
  • a plurality of battery cells are arranged in an array to form a battery cell array.
  • the battery cell array includes multiple rows of battery cell groups.
  • An active safety device is connected between two battery units that are arranged in a row of battery unit groups and are electrically connected to each other.
  • the active safety device is a relay or a fuse.
  • the ratio of the length of at least one single battery to the length of the vehicle ranges from 0.2 to 0.8.
  • the length of the single battery 100 ranges from 600 mm to 2500 mm.
  • the application also provides an electric vehicle, including the battery pack described above.
  • the battery pack of the present application includes at least one battery unit, the battery unit includes at least one battery string, the battery string contains one or at least two single cells, and the battery The voltage difference between the two ends of the string is less than or equal to 60V.
  • the battery string contains at least two single cells, the single cells in the battery string are arranged in sequence along the first direction, and the first direction is parallel to the direction of the front of the vehicle from the rear of the vehicle.
  • the voltage difference between the two ends of the battery string formed by the single batteries arranged in the direction from the rear of the car to the front of the car can be made relatively small, so that during the driving process of the vehicle, even a string in this direction
  • the single cells are short-circuited by the impact. Because the voltage of the string of single cells is relatively small, the impact on the battery pack when the short-circuit occurs is relatively small, which can relatively reduce the battery pack when the battery string is short-circuited. Therefore, it can prevent the battery pack from high-voltage breakdown or high-voltage short circuit, reduce the probability of fire and explosion of the battery pack, and also reduce the occurrence of arcing, which is beneficial to improve the safety of the battery pack.
  • FIG. 1 is a schematic structural diagram of a battery pack provided by an embodiment of the present application.
  • FIG. 2 is a schematic diagram of the impact on the single cells in the battery pack after the bottom of the vehicle is hit by a hard object in the prior art
  • FIG. 3 is another schematic diagram of the structure of the battery pack provided by the embodiment of the present application.
  • FIG. 4 is another schematic structural diagram of the battery pack provided by the embodiment of the present application.
  • FIG. 5 is another schematic diagram of the structure of the battery pack provided by the embodiment of the present application.
  • FIG. 6 is a schematic structural diagram of a single battery provided by an embodiment of the present application.
  • FIG. 7 is another schematic diagram of the structure of the battery pack provided by the embodiment of the present application.
  • FIG. 8 is a schematic diagram of the impact on the single cells in the battery pack after the bottom of the vehicle is hit by a hard object in an embodiment of the present application;
  • FIG. 9 is a schematic cross-sectional view of a single battery provided by an embodiment of the present application.
  • FIG. 10 is a schematic diagram of the pole core group packaged in the packaging film provided by an embodiment of the present application.
  • FIG. 11 is another schematic diagram of the pole core group packaged in the packaging film provided by the embodiment of the present application.
  • FIG. 12 is a schematic diagram of a depression formed on the third surface of a metal shell provided by an embodiment of the present application.
  • the battery pack 200 of the embodiment of the present application may be applied to an electric vehicle to provide power for the electric vehicle.
  • the electric vehicle may be a car or a passenger vehicle, for example.
  • the battery pack 200 includes at least one battery cell 21, the battery cell 21 includes at least one battery string 1006, the battery string 1006 includes one or at least two single cells 100, wherein the voltage difference V between the two ends of the battery string 1006 is less than or equal to 60V.
  • the single cells 100 in the battery string 1006 are sequentially arranged along the first direction AB, where the first direction AB is parallel to the direction from the front to the rear of the vehicle.
  • a vehicle usually has three dimensions: length, width, and height.
  • the length of the vehicle is the distance from the rear to the front of the vehicle.
  • the width of the vehicle refers to the distance between the left and right doors, and the height of the vehicle refers to the distance from the bottom to the top of the vehicle.
  • the length of the vehicle is usually the maximum dimension of the vehicle. Therefore, the first direction AB can also refer to the direction in which the length of the vehicle extends, that is, the direction of the maximum dimension of the vehicle.
  • the battery string 1006 contains multiple single batteries 100, and the multiple single batteries 100 are arranged in sequence along the first direction AB, that is, in the battery unit 21 All of the single cells 100 are arranged in order along the first direction.
  • the single cells 100 in the battery string 1006 may be connected in series, for example, adjacent single cells 100 may be connected in series, so as to realize the series connection of multiple single cells.
  • the voltage difference across the battery string 1006 refers to the voltage difference across a string of single cells connected in series.
  • the battery string 1006 may also contain only one single battery 100.
  • the voltage difference between the two ends of the battery string 1006 refers to the voltage difference between the positive and negative ends of the single battery 100.
  • the voltage difference V between the two ends of the battery string 1006 does not exceed 60V, that is, the voltage difference between the two ends of the battery string formed by the single batteries arranged in the direction from the rear of the vehicle to the front of the vehicle is relatively small, so that during the driving of the vehicle , Even if all the single cells 100 arranged in the direction from the front to the rear of the battery string 1006 are short-circuited due to the impact, since the voltage of the battery string 1006 itself is relatively low, the short-circuit is a low-voltage short-circuit, that is, the battery string 1006 is short-circuited.
  • the voltage generated by the battery pack will also be relatively low, which can prevent the battery pack from high-voltage breakdown or high-voltage short circuit, reduce the probability of fire and explosion of the battery pack, and also reduce the occurrence of arcing, thereby effectively preventing Phenomena such as thermal runaway and heat spread between single cells are beneficial to improve the safety of the battery pack.
  • the energy storage capacity of the battery pack can be increased as much as possible.
  • the voltage difference V across the battery string 1006 is less than or equal to 45V.
  • the short circuit in the battery string 1006 can further reduce the impact on the battery pack and avoid the battery string.
  • the battery pack When 1006 is short-circuited, the battery pack generates a high voltage, which causes problems such as breakdown of the battery pack, and prevents the occurrence of arcing.
  • the voltage difference V between the two ends of the battery string 1006 may be 20-40V, for example, it may be 40V.
  • the inventor of the present application has found through a large number of arc test experiments that, while increasing the battery capacity as much as possible, it is formed by all the single batteries arranged along the direction of the vehicle (also can be understood as the direction from the front of the vehicle to the rear of the vehicle).
  • the voltage difference between the two ends of the battery string 1006 does not exceed 60V, which can effectively prevent the battery pack from catching fire.
  • the experimental data is shown in the following table:
  • the arc test experiment can be carried out by the existing arc test method. During the experiment, the voltage difference between the two ends of the battery string is changed, and then the test vehicle is driven to drive on the test road with obstacles to observe the battery pack. Fire or smoke.
  • the battery unit 21 includes a plurality of battery strings 1006, the plurality of battery strings 1006 are arranged in sequence along the second direction CD, the second direction CD is the width direction of the vehicle, each battery string 1006
  • the voltage difference V between the two ends is less than or equal to 60V.
  • the voltage difference between the two ends of each battery string 1006 can be 45V or 50V.
  • the number of single cells 100 in the battery string 1006 is not specifically limited. For example, it may be 4 or 6, as long as the voltage difference between the two ends of the battery string 1006 does not exceed 60V.
  • the single cells 100 in the same battery string 1006 are connected in series.
  • the battery strings 1006 can be connected in parallel or in series, and can also be connected in series and parallel.
  • adjacent battery strings 1006 are connected in series; or two battery strings 1006 can be connected in parallel and then connected to another
  • the battery string 1006 is connected in series, which is not specifically limited.
  • the number of battery cells 21 is multiple, and the multiple battery cells 21 are connected in series.
  • the battery cell 21 includes a first electrode lead-out end 211 and a second electrode lead-out end 212 that draw current, and the first electrode lead-out end 211 of one of the two adjacent battery cells 21 and the other battery cell 21
  • the second electrode lead-out ends 212 are electrically connected, thereby realizing series connection.
  • a plurality of battery cells 21 are arranged in an array to form a battery cell array.
  • the battery cell array includes multiple rows of battery cell groups 201.
  • the multiple rows of battery cell groups 201 are arranged in sequence along the first direction AB, which can also be understood as each row of cells.
  • the battery pack 202 includes a plurality of battery cells sequentially arranged along the first direction AB.
  • the battery cell array may include only one row of battery cell groups 202; or, as shown in FIG. 5, the battery cell array may also include multiple rows of battery cell groups 202 along the
  • the second direction CD is arranged in sequence. Among them, two adjacent battery cells 21 in the same row of battery cell groups 201 are connected in series, and two adjacent rows of battery cell groups 201 are also connected in series. It is electrically connected through the active safety device 22.
  • an active safety device 22 is connected between two battery cells 21 that are respectively located in two adjacent rows of battery cell groups 201 and electrically connected to each other.
  • the active safety device 22 includes, but is not limited to, a relay, a fuse, or other control switches.
  • the active safety device 22 is used to automatically cut off the connection between two adjacent rows of battery cell groups when the current between two adjacent rows of battery cell groups is too large. When the current between 21 is large, the electrical connection between two adjacent battery cells 21 is cut off.
  • the safety device 22 cuts off the connection between the two rows of battery cells when a short circuit occurs, so that the safety of the battery pack can be further improved.
  • the single battery 100 is approximately a rectangular parallelepiped, and the length of the single battery 100 extends along the first direction AB.
  • the single cell 100 includes a first pole 1001 and a second pole 1002.
  • the first pole 1001 and the second pole 1002 have opposite polarities for drawing current.
  • the first pole 1001 is a positive pole
  • the first pole 1001 is a positive pole
  • the two pole pole 1002 is a negative pole pole.
  • the single battery 100 has two opposite first surfaces 1003 in the first direction AB.
  • the first pole 1001 and the second pole 1002 are located on the same first surface 1003 of the single battery 100, or they can be located on the two first surfaces 1003 respectively.
  • the multiple-row single-cell battery packs are sequentially arranged along the second direction CD .
  • the damaged single battery can be reduced when a collision occurs on the bottom of the vehicle.
  • a plurality of single batteries are arranged along the second direction CD.
  • the first pole 1001 and the second pole 1002 of the single battery 100 may also be arranged on other surfaces of the single battery, specifically, the single
  • the bulk battery 100 has a second surface 1004 facing the top of the vehicle, and the first pole 1001 and the second pole 1002 are located on the second surface 1004.
  • the single battery 100 has two opposite second surfaces 1004 in the third direction EF.
  • the third direction EF is the direction from the bottom to the top of the vehicle.
  • the first pole 1001 and the second pole 1002 may be located on the single battery 100.
  • first pole of the single battery 100 at one end of the battery string 1006 is led out through a wire to correspond to the first electrode lead-out terminal 211 of the battery cell 21, and the second pole of the single battery 100 at the other end of the battery string The column is led out by a wire to correspond to the second electrode lead-out end 212 of the battery cell 21
  • the ratio of the length of the single battery 100 to the length of the vehicle ranges from 0.2 to 0.8.
  • the length L of the single battery 100 ranges from 600 mm to 2500 mm (millimeters), for example, it can be 600 mm, 1200 mm, or 2000 mm.
  • the overall structure of the single battery 100 is more in line with the standardized design, can be used in different battery packs 200, and has a wide range of applications; the thickness of the single battery 100 extends along the second direction CD (that is, the width direction of the vehicle), and the single battery
  • the thickness H of 100 may be greater than 10 mm, for example, may be in the range of 13 mm-75 mm.
  • the single battery 100 includes a metal casing 11 and a plurality of pole core groups 12 encapsulated in the metal casing 11 and sequentially arranged along the first direction AB.
  • a plurality of pole core groups 12 may be connected in series to form a pole core string, and each pole core set 12 contains at least one pole core.
  • the pole core set 12 includes a first electrode 121 and a second electrode 122 that draw current. Further, the pole core set 12 includes a pole core set body 123 and a first electrode 121 and a second electrode that are electrically connected to the pole core set body 123. The two electrodes 122, the first electrode 121 and the second electrode 122 are respectively located on both sides of the electrode core group main body 123 along the first direction AB. In the two adjacent pole core sets 12, the first electrode 121 of one pole core set 12 and the second electrode 122 of the other pole core set 12 are electrically connected to achieve series connection. By connecting a plurality of pole core sets 12 in series, Therefore, the capacity and voltage can be increased by a single single cell 100, and the manufacturing process and cost can be reduced.
  • the series connection in this embodiment may be a series connection between two adjacent pole core groups 12, and the specific implementation manner may be that the first electrode 121 and the first electrode 121 on the two adjacent pole core groups 12 are connected in series.
  • the second electrode 122 is directly connected, or may be electrically connected through an additional conductive component. If the pole core set 12 only contains one pole core, the first electrode 121 and the second electrode 122 may be the positive and negative lugs of the pole or the negative and positive lugs respectively. If multiple pole cores are included, the lead-out parts of the first electrode 121 and the second electrode 122 may be electrode leads. Among them, the "first" and "second" in the first electrode 121 and the second electrode 122 are only used to distinguish between names and not to limit the number. For example, the first electrode 121 and the second electrode 122 may each contain one or Multiple.
  • the metal shell 11 includes a shell body 111 having an opening and a cover plate 112.
  • the cover 112 and the opening of the shell body 11 are connected in a sealed manner to jointly enclose a sealed accommodating chamber, and a pole core string formed by a plurality of pole core groups 12 in series is accommodated in the accommodating chamber.
  • Both ends of the pole core string respectively contain a first electrode and a second electrode.
  • the first electrode of the pole core string is also the first electrode 121 of the pole core set 12 located at one end of the pole core string.
  • the electrode is also the second electrode 122 of the pole core set 12 located at the other end of the pole core string.
  • the first electrode and the second electrode located at the two ends of the electrode core string are respectively led out from the cover plate 112 to form the first electrode post 1001 and the second electrode post 1002 of the single cell 100 respectively.
  • the shell body 111 may be open at both ends, and the number of the cover plates 112 may be two, so that the two cover plates 112 are respectively connected with the two end openings of the shell body 111 in a sealed manner. Housing chamber.
  • the first electrode and the second electrode located at both ends of the pole core string can be led out from the two cover plates 112 respectively to form the first pole 1001 and the second pole 1002 of the single cell 100, respectively.
  • the first pole 1001 and the second pole 1002 are respectively located on the first surface 1003 of the single cell 100 at both ends of the unit cell 100 in the first direction AB.
  • the first electrode and the second electrode located at both ends of the pole core string may also be led out from the same cover plate 112 to form the first pole 1001 and the second pole of the single cell 100, respectively. 1002.
  • the first pole 1001 and the second pole 1002 are respectively located on the first surface 1003 of the single cell 100 at the same end in the first direction AB.
  • the shell body 111 may be provided with an opening at only one end, and the number of the cover plate 112 is one, so that one cover plate 112 is sealedly connected to the one end opening of the shell body 111.
  • the first electrode and the second electrode located at both ends of the pole core string are led out from the same cover plate 112 to form the first pole 1001 and the second pole 1002 of the single cell 100 respectively.
  • the The first pole 1001 and the second pole 1002 are respectively located at the same end of the single cell 100.
  • the first electrode and the second electrode located at the two ends of the pole core string may not be led out of the cover plate 112, and the cover plate 112 is provided with the first pole 1001 and the second pole 1002, Furthermore, the first and second electrode terminals can be both arranged on the same cover plate 112, or can be respectively arranged on the two cover plates 112. At this time, the first electrode and the second electrode located at both ends of the electrode core string They are respectively electrically connected to the first electrode terminal and the second electrode terminal on the cover plate 112, which will not be repeated here.
  • multiple pole core groups 12 can also be connected in series + parallel.
  • multiple pole core groups 12 can form two pole core strings.
  • multiple pole core groups 12 can be divided into Two parts, the pole core groups 12 in each part are connected in series to form a pole core string, and the two pole core strings are connected in parallel.
  • a plurality of pole core groups 12 can also be reasonably divided into three or more parts, the pole core sets 12 in each part are connected in series to form a pole core string, and the plurality of pole core strings are connected in parallel.
  • the multiple pole core groups 12 in the single battery 100 are divided into multiple parts, and the multiple pole core groups 12 in each part are connected in series to form a pole core string, so that each pole core string can have a certain size.
  • the capacitance of the multiple pole core strings can be superimposed, so that the single battery 100 has a larger capacitance, which is conducive to lengthening The power supply time of the single battery 100.
  • a packaging film 13 is further provided between the metal shell 11 and the pole core set 12, that is, the pole core set 12 is encapsulated in the packaging film 13.
  • the secondary packaging of the pole core assembly 12 can be achieved through the packaging film 13 and the metal casing 11, which is beneficial to improve the sealing effect of the single cell 100.
  • electrolyte solution is also injected into the packaging film 13. Therefore, through the above method, the contact of the electrolyte with the metal casing 11 can also be avoided, and the corrosion of the metal casing 11 or the decomposition of the electrolyte can be avoided.
  • the air pressure between the metal casing 11 and the packaging film 13 is lower than the air pressure outside the metal casing 11, and the air pressure in the packaging film 13 is lower than the air pressure between the metal casing 11 and the packaging film 13.
  • air pressure is an abbreviation for atmospheric pressure. It is the atmospheric pressure acting on a unit area, which is equal to the weight of a vertical air column extending up to the upper boundary of the atmosphere per unit area.
  • the air pressure between the metal shell 11 and the packaging film 13 is also the air pressure in the space between the metal shell 11 and the packaging film 13, which is lower than the air pressure outside the metal shell 11. Therefore, in the embodiment of the present application , The metal shell 11 and the packaging film 13 are in a negative pressure state, so the metal shell 11 is dented or deformed under the action of atmospheric pressure, and the gap between the metal shell 11 and the pole core assembly 12 is reduced accordingly. , The space for the pole core group 12 to move or the displacement between each other is reduced, thereby reducing the movement of the pole core set 12 and the relative displacement between the pole core sets 12, improving the stability of the single battery 100, and The strength of the single battery 100 and the safety performance of the single battery 100.
  • the space between the metal casing 11 and the packaging film 13 can be evacuated to make the metal casing 11 and the packaging film 13 in a negative pressure state, thereby making the metal casing 11 and the internal
  • the pole core set 12 is as close as possible to reduce internal gaps, prevent the pole core from moving in the metal shell, and at the same time prevent relative displacement between the pole cores, and reduce the occurrence of current collector damage, diaphragm wrinkles, and active material shedding.
  • the mechanical strength of the entire single battery 100 is improved, the service life of the single battery 100 is prolonged, and the safety performance of the single battery 100 is improved.
  • the air pressure value between the metal casing 11 and the packaging film 13 is P1, and the value range of P1 may be -100Kpa to -5Kpa, and more preferably, the value of P1 may be -75Kpa to- 20Kpa.
  • the metal casing 11 and the packaging film 13 may also be in a vacuum state.
  • the air pressure value in the packaging film 13 is P2, and the value range of P2 can be -100Kpa to -20Kpa.
  • the relationship between P1 and P2 satisfies: P1>P2, and the range of P1/P2 is 0.05-0.85.
  • the pole core assembly 12 in the present technology adopts a secondary sealing mode.
  • the battery pole core assembly 12 is encapsulated in the packaging film 13, in order to avoid the occurrence of due to the packaging film 13 Excessive internal air pressure can cause damage to the outer drum of the packaging film 13, and we choose that the air pressure between the metal casing 11 and the packaging film 13 is greater than the air pressure in the packaging film 13.
  • P1/P2 we have verified through a large number of experiments that when P1/P2 is in the above range, the reliability of the secondary sealing of the single battery 100 is better guaranteed, and at the same time, the interface between the 100 pole pieces of the single battery is guaranteed, and the The gap between the pole pieces allows lithium ions to be better conducted.
  • the packaging film 13 includes one, a plurality of pole core groups 12 connected in series are encapsulated in the same packaging film 13, and the first pole core group 12 of the two pole core groups 12 connected in series The connection point between one electrode 121 and the second electrode 122 of the other electrode core group 12 is located in the packaging film 13.
  • the packaging film 13 is integrally provided, and a plurality of pole core groups 12 are packaged in the same packaging film 13.
  • a plurality of pole core groups 12 can be connected in series first, and then a whole piece of packaging film 13 can be used to wrap the series pole core groups 12, for example, the series pole cores can be connected in series.
  • the group 12 is placed on a part of the packaging film 13 (or a groove can be made on a part of the packaging film 13 in advance, and then a plurality of pole core groups 12 connected in series are placed in the groove), and then the packaging film 13
  • the other part of the area is folded in half toward the direction of the pole core group 12, and then the two partial areas of the packaging film 13 are heat-melt sealed by a hot melt process, thereby encapsulating the series of pole core groups 12 in the same packaging film 13.
  • an encapsulation portion 131 is formed at a position opposite to the first electrode 121 and/or the second electrode 122 in the encapsulation film 13 to isolate the main body 123 of the adjacent two-electrode core group, and one of the two electrode cores in the adjacent two-electrode core group 12 is formed. At least one of the first electrode 121 of the group 12 and the second electrode 122 of the other electrode core group 122 is located in the packaging part 131.
  • the encapsulation part 131 isolates the main bodies 123 of the plurality of pole core groups to prevent the electrolyte of the plurality of pole core sets 12 from circulating each other, the plurality of pole core sets 12 will not affect each other, and the plurality of pole core sets 12 The electrolyte will not decompose due to excessive potential difference, ensuring the safety and service life of the single battery 100.
  • the packaging portion 131 may have various implementations.
  • a cable tie may be used to tie the packaging film 13 to form the packaging portion 131, or the packaging film 13 may be directly thermally fused to form the packaging portion 131.
  • a spacer is directly arranged between the two pole core groups 12 to form the encapsulation portion 131, and the specific manner of the encapsulation portion 131 is not particularly limited.
  • FIG. 11 there are a plurality of packaging films 13, wherein at least one pole core group 12 is encapsulated in one packaging film 13 to form a pole core assembly, and the plurality of pole core assemblies are connected in series. .
  • the number of packaging films 13 corresponds to the number of pole core groups 12 one-to-one, and each pole core set 12 is individually packaged in one packaging film 13.
  • a packaging film 13 can be separately sleeved outside each pole core group 12, and then multiple pole core assemblies are connected in series.
  • At least one of the first electrode 121 and the second electrode 122 of the pole core set 12 extends out of the packaging film 13.
  • the first electrode 121 may extend out of the packaging film 13, or the second electrode 122 may extend out of the packaging film 13.
  • the film 13 or the first electrode 121 and the second electrode 122 may both extend out of the packaging film 13.
  • the arrangement direction of the plurality of pole core groups 12 is the first direction AB
  • the length direction of the pole core groups 12 extends along the first direction AB
  • the length of the single cell 100 also extends along the first direction AB. That is, a plurality of pole core groups 12 are arranged in sequence along the length direction of the single battery 100, and the first electrode 121 and the second electrode 122 of the pole core set 12 are respectively located on both sides of the pole core set 12 along the first direction AB, namely
  • the multiple pole core groups 12 adopt a "head-to-head" arrangement, which can easily realize the pairwise series connection between the pole core groups 12, and the connection structure is simple. In addition, this arrangement makes it easier to manufacture long-length single cells 100.
  • the single battery 100 is directly mounted on the battery pack shell, which can save the internal space of the battery pack, improve the volume utilization rate of the battery pack, and help reduce the battery pack. the weight of.
  • the embodiment of the present application can greatly reduce the internal resistance of the battery, and avoid problems caused by battery overheating under high power output, fast charging, and the like.
  • the metal casing 11 has two opposite third surfaces 1005 along the second direction CD. ". Wherein, at least one third surface 1005 is recessed toward the inside of the metal shell 11, so that the metal shell 11 and the pole core assembly 12 can be as close as possible.
  • the depression 114 on the third surface 1005 of the metal shell 11 may be, for example, a depression formed when the metal shell 11 is evacuated. That is, when the space between the metal casing 11 and the packaging film 13 is evacuated so that the air pressure between the metal housing 11 and the encapsulation film 13 is lower than the air pressure outside the metal casing 11, as the air extraction progresses , The third surface 1005 of the metal shell 11 easily forms a depression 114 in the metal shell 11.
  • the battery usually swells due to the expansion of the material itself, gas production from the electrolyte, etc., and the area with the largest expansion and deformation is often located on the large surface of the battery.
  • the large surface of the battery is limited to a slight indentation by vacuuming in the initial state of the battery, which can effectively alleviate the squeezing between the batteries after the battery expands, and improve the life and safety performance of the battery and the entire system.
  • FIG. 12 it is also possible to preliminarily form a depression on the third surface 1005 of the metal shell 11, and then perform an air extraction process on the inside of the metal shell 11.
  • the two opposite third surfaces 1005 of the metal shell 11 are both recessed toward the inside, so as to clamp the pole core assembly 12 through the recessed area.
  • an exhaust hole may be provided on the metal shell 11, and the space between the metal shell 11 and the packaging film 13 can be evacuated through the exhaust hole.
  • the vent hole needs to be sealed, so a sealing element is also provided in the vent hole to seal the vent hole.
  • the sealing member may be, for example, a plug, a rubber member, etc., which is not limited.
  • a gap is provided between the pole core set 12 and the inner surface of the metal shell 11; this gap is convenient for the pole core set 12 to be easily installed into the metal shell 11.
  • the metal shell 11 is pressed on the outer surface of the pole core set 12 in the second direction to clamp the pole core set 12, thereby reducing the pole core set 12 in the metal shell 11
  • the internal movement space improves the safety performance of the single battery 100.
  • the metal shell 11 has high strength and good heat dissipation effect.
  • the metal shell 11 may include, but is not limited to, an aluminum shell or a steel shell.
  • the thickness of the metal shell 11 is 0.05 mm-1 mm.
  • the thicker thickness of the metal shell 11 will not only increase the weight of the single battery 100 and reduce the capacity of the single battery 100, but also the thickness of the metal shell 11 is too thick.
  • One side of the group 12 is recessed or deformed, which cannot reduce the distance between the metal shell 11 and the electrode core group 12, and thus cannot effectively realize the positioning of the electrode core group 12. Not only that, if the metal shell 11 is too thick, it will increase the cost of air extraction, thereby increasing the manufacturing cost.
  • the present application limits the thickness of the metal shell 11 to the above range, which not only ensures the strength of the metal shell 11, but also does not reduce the capacity of the single cell 100. It can also make the metal shell 11 easier under negative pressure. The deformation occurs, reducing the distance between the metal shell 11 and the pole core set 12, thereby reducing the movement of the pole core set 12 inside the metal shell 11 and the relative displacement between the pole core sets 12.
  • the packaging film 13 includes a laminated non-metal outer film and a non-metal inner film, and the inner film is located between the outer film and the electrode core group 12.
  • the inner film has good chemical stability.
  • materials with anti-corrosion properties of electrolyte can be used, such as polypropylene (PP, Polypropylene), polyethylene (PE, Polyethylene) or polyethylene terephthalate (PET, Polyethylene terephthalate), or a combination of the above materials.
  • the outer film is a protective layer.
  • the outer film can prevent the penetration of air, especially water vapor, oxygen, etc.
  • the material can be polyethylene terephthalate, polyamide (PA, Polyamide) or polypropylene, or it can be Multiple combinations of the above materials.
  • the melting point of the outer film is greater than the melting point of the inner film, so that the outer film will not be melted during hot-melt sealing, and the inner film can be melted in time to ensure excellent sealing performance .
  • the melting point difference between the outer layer film and the inner layer film ranges from 30°C to 80°C.
  • the melting point difference between the two can be 50°C or 70°C. The specific material selection can be determined according to actual needs.
  • the non-metal outer layer film and the non-metal inner layer film are bonded and compounded with an adhesive.
  • the material of the outer film may be PP
  • the material of the inner film may be PET
  • the adhesive for bonding the two may be, for example, a polyolefin adhesive to form a composite film.
  • a double-layer non-metallic film is used to form the encapsulation film 13 to encapsulate the pole core assembly 12.
  • the non-metallic encapsulation film 13 has higher tensile strength and elongation at break, which can reduce the need for single cells.
  • the thickness limit of 100 makes the produced single cell 100 have a larger thickness.
  • the thickness of the single battery 100 of this embodiment can be extended in a wide range, for example, it can be greater than 10 mm, for example, it can be in the range of 13-75 mm.
  • the packaging film 13 may be an aluminum plastic film.
  • the single battery 100 is a lithium ion battery.
  • a certain gap is reserved between the single cells 100 to reserve a buffer space for the expansion of the single cells 100.
  • the swelling of the single battery 100 is related to the thickness of the single battery 100.
  • the greater the thickness of the battery the easier the single battery 100 to swell.
  • the limit is 0.001-0.15, which can make full use of the space of the battery pack 200, improve the utilization rate of the battery pack 200, and can also provide a better buffer effect for the expansion of the single battery 100.
  • the single battery 100 expands, heat is generated.
  • a certain gap is reserved between the single batteries 100.
  • the gap can also serve as a heat dissipation channel, such as an air duct.
  • the larger surface of the single battery 100 has a better heat dissipation effect. Therefore, the heat dissipation efficiency of the battery pack 200 can also be improved, and the safety performance of the battery pack 200 can be improved.
  • the gap between the single batteries 100 can be understood as the single battery 100 is not provided with any structural parts, and a certain space is simply reserved. It can also be understood that the single battery 100 is provided with other structural parts to make the single battery 100 and the single battery 100 are separated by the structural member.
  • the gap between the single cells 100 should be understood as the distance between the single cells 100 on both sides of the structural member. The spacing between the bulk cells 100.
  • the structural parts include but are not limited to aerogel, thermally conductive structural glue or thermal insulation cotton.
  • the present application also provides an electric vehicle including the above-mentioned battery pack 200.
  • the electric vehicle and the above-mentioned battery pack 200 have the same advantages over related technologies, which will not be repeated here.
  • connection should be understood in a broad sense, unless otherwise clearly specified and limited.
  • it can be a fixed connection or a detachable connection.
  • Connected or integrally connected it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication between two components.
  • connection should be understood in a broad sense, unless otherwise clearly specified and limited.
  • it can be a fixed connection or a detachable connection.
  • Connected or integrally connected it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication between two components.
  • the specific meanings of the above terms in this application can be understood under specific circumstances.
  • the description with reference to the terms “embodiment”, “specific embodiment”, “example”, etc. means that the specific feature, structure, material, or characteristic described in combination with the embodiment or example is included in at least the application. In one embodiment or example. In this specification, the schematic representations of the above-mentioned terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

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Abstract

一种电池包(200)及电动车，电池包(200)包括至少一个电池单元(21)，电池单元(21)包括至少一个电池串(1006)，所述电池串(1006)中含有一个或至少两个单体电池(100)，电池串(1006)两端的电压差小于或等于60V，其中当电池串(1006)中含有至少两个单体电池(100)时，电池串(1006)中的单体电池(100)沿第一方向依次排列，第一方向与车辆车尾到车头的方向平行。

Description

电池包及电动车
相关申请的交叉引用
本申请要求“比亚迪股份有限公司”于2020年02月28日提交的、名称为“电池包及电动车”的、中国专利申请号“202010129989.1”的优先权。
技术领域
本申请涉及车辆制造技术领域，尤其涉及一种电池包及电动车。
背景技术
在电动车中，受电动车的空间限制，电池包通常固定在车辆底部，也即车辆底盘上。然而，由于车辆底部距离地面较近，因此在车辆行驶过程中安装在车辆底部的电池包极容易受到撞击，从而导致电池包中的单体电池容易产生短路，尤其是在车辆行驶过程中，车辆底部受到的撞击动作通常会从车头持续到车尾，因而会导致电池包中的一串单体电池发生短路。
作为电动汽车的动力来源，电池包具有很高的能量密度，高电压和高能量密度同时也意味着高危险性，当电池包中的一串单体电池发生短路时，如果这串电池间存在高电压，会导致电池包瞬间产生高压击穿或高压短路，使得电池包容易着火爆炸，也容易产生拉弧现象，对驾乘人员的生命安全造成威胁。
申请内容
本申请旨在至少解决现有技术中存在的技术问题之一。为此，本申请提出一种电池包及电动车，能够相对地降低电池串短路时电池包所产生的电压，有利于防止电池包产生高压击穿或高压短路，提高电池包的安全性。
本申请进一步地提出了一种电动车。
为了实现上述目的，本申请提供一种电池包，用于为车辆提供电能，包括至少一个电池单元，所述电池单元包括至少一个电池串，所述电池串含有一个或至少两个单体电池，所述电池串两端的电压差小于或等于60V；当所述电池串中含有至少两个单体电池时，所述电池串中的单体电池沿第一方向依次排列，所述第一方向与车辆车尾到车头的方向平行。
在本申请的一些示例中，所述电池串两端的电压差小于或等于45V。
在本申请的一些示例中，所述电池串两端的电压差为20～40V。
在本申请的一些示例中，所述电池单元包括多个所述电池串，多个所述电池串沿第二方向依次排列，所述第二方向为车辆的宽度方向。
在本申请的一些示例中，所述电池串之间为串联和/或并联。
在本申请的一些示例中，当所述电池串中含有至少两个单体电池时，所述电池串中的单体电池之间为串联。
在本申请的一些示例中，所述单体电池的长度沿第一方向延伸。
在本申请的一些示例中，所述单体电池包括第一极柱和第二极柱，且所述单体电池沿第一方向具有相对的两个第一表面；所述第一极柱和第二极柱位于单体电池的同一个所述第一表面上，或者分别位于单体电池的两个第一表面上。
在本申请的一些示例中，所述单体电池包括第一极柱和第二极柱，所述单体电池具有面对车辆顶部的第二表面，所述第一极柱和第二极柱位于所述第二表面上。
在本申请的一些示例中，所述电池单元有多个，所述电池单元之间为串联。
在本申请的一些示例中，多个电池单元呈阵列排列以形成电池单元阵列，所述电池单元阵列包括多排电池单元组，多排电池单元组沿第一方向依次排列，分别位于相邻两排电池单元组且相互电连接的两个电池单元之间，连接有主动安全装置。
在本申请的一些示例中，所述主动安全装置为继电器或保险丝。
在本申请的一些示例中，至少一个所述单体电池的长度与所述车辆的长度的比值范围为0.2-0.8。
在本申请的一些示例中，所述单体电池100的长度范围为600mm-2500mm。
本申请还提供一种电动车，包括上述所述的电池包。
与现有技术相比，本申请具有的有益效果为：本申请的电池包中，包括至少一个电池单元，电池单元包括至少一个电池串，电池串中含有一个或至少两个单体电池，电池串两端的电压差小于或等于60V，当电池串中含有至少两个单体电池时，电池串中的单体电池沿第一方向依次排列，第一方向与车辆车尾到的车头的方向平行，由此，通过本方案，可以使得在车尾到车头的方向上排列的单体电池所形成的电池串两端的电压差比较小，从而在车辆行驶过程中，即使在该方向上的一串单体电池均受撞击而发生短路，由于该串单体电池的电压本身比较小，因此其短路时对电池包的影响也相对比较小，从而可以相对地降低电池串发生短路时电池包所产生的电压，从而可以防止电池包产生高压击穿或高压短路，减小电池包发生着火爆炸的几率，同时也可以减少拉弧现象的产生，有利于提高电池包的安全性。
本申请的附加方面和优点将在下面的描述中部分给出，部分将从下面的描述中变得明显，或通过本申请的实践了解到。
附图说明
图1是本申请实施例提供的电池包的一结构示意图；
图2是现有技术中车辆底部受到硬物撞击后对电池包内的单体电池的影响示意图；
图3是本申请实施例提供的电池包的另一结构示意图；
图4是本申请实施例提供的电池包的又一结构示意图；
图5是本申请实施例提供的电池包的又一结构示意图；
图6是本申请实施例提供的单体电池的结构示意图；
图7是本申请实施例提供的电池包的又一结构示意图；
图8是本申请实施例中车辆底部受到硬物撞击后对电池包内的单体电池的影响示意图；
图9是本申请实施例提供的单体电池的截面示意图；
图10是本申请实施例提供的极芯组封装在封装膜内的一示意图；
图11是本申请实施例提供的极芯组封装在封装膜内的另一示意图；
图12是本申请实施例提供的金属壳体第三表面形成有凹陷的示意图。
具体实施方式
下面详细描述本申请的实施例，所述实施例的示例在附图中示出，其中自始至终相同或类似的标号表示相同或类似的元件或具有相同或类似功能的元件。下面通过参考附图描述的实施例是示例性的，仅用于解释本申请，而不能理解为对本申请的限制。
在本申请的描述中，需要理解的是，术语“中心”、“纵向”、“横向”、“长度”、“宽度”、“厚度”、“上”、“下”、“前”、“后”、“左”、“右”、“竖直”、“水平”、“顶”、“底”、“内”、“外”、“轴向”、“径向”、“周向”等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本申请和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本申请的限制。
请参阅图1，本申请实施例的电池包200，其可以应用于电动车，为电动车提供动力，电动车如可以是小轿车或客运车等。其中，电池包200包括至少一个电池单元21，电池单元21包括至少一个电池串1006，电池串1006含有一个或至少两个单体电池100，其中电池串1006两端的电压差V小于或等于60V。
当电池串1006中含有至少两个单体电池100时，电池串1006中的单体电池100沿第一 方向AB依次排列，其中第一方向AB与车辆车头到车尾的方向平行。
可以理解的是，车辆通常具有长度、宽度和高度三个尺寸，车辆的长度也即车尾到车头的距离，车辆的宽度指左右两侧车门的距离，车辆的高度指车辆底部到顶部的距离，对于大部分车辆而言，车辆长度通常为车辆的最大尺寸，因此，第一方向AB也可以是指车辆的长度延伸方向，也即车辆的最大尺寸方向。
在一些实施例中，电池单元21中可以是只有一个电池串1006，电池串1006含有的单体电池100为多个，多个单体电池100沿第一方向AB依次排列，即电池单元21中的所有单体电池100沿第一方向依次排列。其中，电池串1006中的单体电池100之间可以为串联，例如可以是相邻单体电池100之间串联，从而实现多个单体电池的串联。此时，电池串1006两端的电压差是指串联的一串单体电池两端的电压差。
在其他一些实施例中，电池串1006中也可以是仅含有一个单体电池100，此时电池串1006两端的电压差指的是该一个单体电池100的正负极两端的电压差。
传统电池包中，如图2所示，为了尽可能提高电池容量，电池包中会排布较多的单体电池，当较多的单体电池沿车辆车尾到车头的方向(第一方向AB)排列时，在车辆行进过程中一旦车辆底部受到硬物G撞击，车辆底部受到的撞击动作通常会从车头持续到车尾，因此电池包内沿车头到车尾排列的所有单体电池(图中阴影部分的单体电池)都有可能会受到撞击而一起变形、破裂，从而造成较多单体电池之间短路，导致电池包产生更高的电压，引发电池着火爆炸。
本申请实施例通过使电池串1006两端的电压差V不超过60V，即在车尾到车头的方向上排列的单体电池所形成的电池串两端的电压差比较小，从而在车辆行驶过程中，即使电池串1006中沿车头到车尾方向排列的所有单体电池100都受撞击而发生短路，由于该电池串1006的电压本身比较低，因此其短路为低压短路，即电池串1006发生短路时导致电池包所产生的电压也会相对比较低，从而可以防止电池包产生高压击穿或高压短路，减小电池包发生着火爆炸的几率，同时也可以减少拉弧现象的产生，从而有效防止单体电池之间的热失控和热蔓延等现象，有利于提高电池包的安全性。
另外，通过使电池串1006两端的电压差不超过60V，在可以减少拉弧现象产生的同时，还能够尽可能地提高电池包的储能容量。
进一步地，电池串1006两端的电压差V小于或等于45V，通过使电池串1006两端的电压差V较小，从而可以进一步在电池串1006发生短路相对地降低对电池包的影响，避免电池串1006短路时电池包产生高电压而引起电池包发生击穿等问题，防止拉弧现象的产生。其中，电池串1006两端的电压差V可以是20～40V，例如可以是40V。
本申请发明人通过大量拉弧测试实验发现，在尽可能提高电池容量的情况下，通过使沿车辆行驶方向(也可以理解为车辆车头到车尾的方向)排列的所有单体电池所形成的电池串1006两端的电压差不超过60V，可以有效地防止电池包起火，如下表所示的实验数据：
Figure PCTCN2021074132-appb-000001
上述实验数据表明，当电池串1006两端的电压差不超过60V时，电池包不会产生起火冒烟等现象，不仅能够满足动力要求，也能够提高电池包的安全性能。
其中拉弧测试实验可以采用现有的拉弧测试方式进行，在实验过程中主要是通过改变电池串两端的电压差，然后驱使试验车在有障碍物的测试路面上行驶，以观察电池包的起火或冒烟情况。
参阅图3，在本申请实施例中，电池单元21中包括多个电池串1006，多个电池串1006沿第二方向CD依次排列，第二方向CD为车辆的宽度方向，每个电池串1006两端的电压差 V小于或等于60V，例如可以使每个电池串1006两端的电压差为45V或50V等。
其中，电池串1006中的单体电池100的数量不做具体限定，例如可以是4个或6个等，只要满足电池串1006两端的电压差不超过60V即可。
其中，同一电池串1006中的单体电池100为串联关系。而电池串1006之间可以是并联或者串联，还可以是串并联结合的连接方式，例如，相邻电池串1006之间为串联；或者可以是将两个电池串1006先并联然后再与另外的电池串1006串联，对此不做具体限定。
如图4所示，本申请实施例中，电池单元21的数量为多个，多个电池单元21之间为串联。具体而言，电池单元21含有引出电流的第一电极引出端211和第二电极引出端212，相邻两电池单元21中的一个电池单元21的第一电极引出端211和另一电池单元21的第二电极引出端212电连接，从而实现串联。
其中，多个电池单元21呈阵列排列以形成电池单元阵列，该电池单元阵列包括多排电池单元组201，多排电池单元组201沿第一方向AB依次排列，也可以理解为每列单体电池组202上含有沿第一方向AB依次排列的多个电池单元。如图4所示，电池单元阵列中可以是仅包括一列电池单元组202；或者，如图5所示，电池单元阵列中也可以是包括多列电池单元组202，多列电池单元组202沿第二方向CD依次排列，其中，同一排电池单元组201中的相邻两个电池单元21之间为串联，且相邻两排电池单元组201也是串联，相邻两排电池单元组之间通过主动安全装置22电连接。
其中，分别位于相邻两排电池单元组201且相互电连接的两个电池单元21之间，连接有主动安全装置22。
如图4所示，每排电池单元组中有1个电池单元21，因此分别在相邻两排电池单元组的两电池单元21中，一个电池单元21的第一电极引出端211和另一个电池单元21的第二电极引出端212之间通过主动安全装置22电连接。该主动安全装置22包括但不限于继电器、保险丝或其他控制开关等。主动安全装置22用于在相邻两排电池单元组之间的电流过大时自动切断相邻两排电池单元组之间的连接，如图1的实施例，用于在相邻两电池单元21之间的电流较大时切断相邻两个电池单元21之间的电连接。
当同一列的多个电池单元21均存在短路单体电池时，在电池单元21之间势必会形成高压回路，电路中的电流会增大，通过在相邻两排电池单元组之间设置主动安全装置22，以在发生短路时切断两排电池单元之间的连接，从而可以进一步提高电池包的安全性。
参阅图6，并结合图1，本申请实施例中，单体电池100大致为长方体，其中单体电池100的长度沿第一方向AB延伸。单体电池100包括第一极柱1001和第二极柱1002，第一极柱1001和第二极柱1002的极性相反，用于引出电流，例如第一极柱1001为正极极柱，第二极柱1002为负极极柱。
单体电池100在第一方向AB具有相对的两个第一表面1003，第一极柱1001和第二极柱1002位于单体电池100的同一个第一表面1003上，也可以分别位于两个第一表面1003上。
对于一个电池单元21而言，当电池单元21中有多个单体电池100，多个单体电池100排列形成多列单体电池组时，多列单体电池组沿第二方向CD依次排列。本申请实施例中，通过使单体电池100的长度沿第一方向AB延伸，且多个单体电池沿第二方向CD排列，由此可以在车辆底部发生撞击时减少受损的单体电池数量，如图8所示，多个单体电池沿第二方向CD排布，在车辆行进过程中一旦车辆底部受到硬物G撞击，可以减少受异物撞击影响的单体电池(图中阴影部分表示的单体电池)数量，避免整个电池包中的单体电池都遭受损坏，因此，通过本实施例可以进一步提高电池包的安全性。
在其他实施例中，如图7所示，并结合图6，单体电池100的第一极柱1001和第二极柱1002还可以设置在单体电池的其他表面上，具体而言，单体电池100具有面对车辆顶部的第二表面1004，第一极柱1001和第二极柱1002位于第二表面1004上。
其中，单体电池100在第三方向EF具有相对的两个第二表面1004，第三方向EF为车 辆底部到顶部的方向，第一极柱1001和第二极柱1002可以位于单体电池100的面对车辆顶部的第二表面1004上。
需要说明的是，电池串1006一端的单体电池100的第一极柱通过导线引出以对应为电池单元21的第一电极引出端211，该电池串另一端的单体电池100的第二极柱通过导线引出以对应为电池单元21的第二电极引出端212
本申请实施例中，单体电池100的长度与车辆的长度的比值范围为0.2-0.8。具体地，本申请实施例中，单体电池100的长度L的范围为600mm-2500mm(毫米)，例如，可以是600mm、1200mm或者2000mm等，单体电池100的长度尺寸在该范围内时，单体电池100的整体结构更符合标准化的设计，可通用于不同的电池包200中，适用范围广；单体电池100的厚度沿第二方向CD(即车辆的宽度方向)延伸，单体电池100的厚度H可以是大于10mm，例如可以在13mm-75mm的范围。
更具体地，请一并参阅图6至图12，单体电池100包括金属壳体11和封装于金属壳体11内且沿第一方向AB依次排列的多个极芯组12。多个极芯组12之间可以是串联形成一极芯串，且每个极芯组12至少含有一个极芯。
其中，极芯组12含有引出电流的第一电极121和第二电极122，进一步而言，极芯组12包括极芯组主体123以及与极芯组主体123电连接的第一电极121和第二电极122，第一电极121和第二电极122沿第一方向AB分别位于极芯组主体123的两侧。相邻的两个极芯组12中，其中一个极芯组12的第一电极121和另外一个极芯组12的第二电极122电连接以实现串联，通过使多个极芯组12串联，由此可以通过单个单体电池100即可实现容量和电压的提高，减小制造工艺和成本。
需要说明的是，本实施例的串联方式可以为相邻的两个极芯组12之间的串联连接，实现的具体方式可以为相邻的两个极芯组12上的第一电极121和第二电极122直接连接，也可以是通过额外的导电部件实现电连接。如果极芯组12仅含有一个极芯的情况下，第一电极121和第二电极122可以分别为极芯的正极耳和负极耳或者分别为负极耳和正极耳。如果含有多个极芯的情况下，第一电极121和第二电极122的引出部件可以为电极引线。其中，第一电极121和第二电极122中的“第一”和“第二”仅用于名称区分，并不用于限定其数量，例如第一电极121和第二电极122均可以含有一个或者多个。
进一步地，金属壳体11包括具有开口的壳本体111和盖板112。盖板112与壳本体11的开口密封连接，以共同围成密封的容纳腔室，多个极芯组12串联形成的极芯串容置于该容纳腔室内。极芯串的两端分别含有第一电极和第二电极，该极芯串的第一电极也即位于该极芯串一端的极芯组12的第一电极121，该极芯串的第二电极也即位于该极芯串另一端的极芯组12的第二电极122。
其中，在一些实施例中，位于极芯串两端的第一电极和第二电极分别从盖板112引出，以分别形成单体电池100的第一极柱1001和第二极柱1002。
具体地，在一些实施方式中，壳本体111可以是两端开口，盖板112的数量可以为两个，从而两个盖板112分别与壳本体111的两端开口密封连接，以形成密封的容纳腔室。此种方式中，位于极芯串两端的第一电极和第二电极可以是分别从两个盖板112引出，以分别形成单体电池100的第一极柱1001和第二极柱1002，此时所述第一极柱1001和第二极柱1002分别位于单体电池100在第一方向AB两端的第一表面1003上。当然，在其他实施例中，位于极芯串两端的第一电极和第二电极也可以是从同一个盖板112引出，以分别形成单体电池100的第一极柱1001和第二极柱1002，此时所述第一极柱1001和第二极柱1002分别位于单体电池100在第一方向AB同一端的第一表面1003上。
在另一些实施方式中，壳本体111上可以是仅在一端设置有开口，盖板112的数量为一个，从而一个盖板112与壳本体111的一端开口密封连接。此种方式中，位于极芯串两端的第一电极和第二电极从同一个盖板112引出，以分别形成单体电池100的第一极柱1001和第二极柱1002，此时所述第一极柱1001和第二极柱1002分别位于单体电池100的同一 端。
可以理解的是，在另一些实施例中，位于极芯串两端的第一电极和第二电极可以不引出盖板112，盖板112上设置有第一极柱1001和第二极柱1002，进一步而言，第一、第二电极端子可以是均设置在同一个盖板112上，也可以分别设置在两个盖板112上，此时位于极芯串两端的第一电极和第二电极分别与盖板112上的第一电极端子和第二电极端子电连接，此处不做赘述。
需要说明的是，多个极芯组12也可以是串联+并联的方式连接在一起，例如，多个极芯组12可以形成两个极芯串，具体可以将多个极芯组12分为两部分，每一部分中的极芯组12串联形成一极芯串，两个极芯串之间并联。当然，多个极芯组12也可以合理划分为三部分或者更多的部分，每一部分中的极芯组12串联形成一极芯串，多个极芯串之间并联。可以理解的是，单体电池100中的多个极芯组12分为多个部分，每一部分中的多个极芯组12串联形成一极芯串，使得每一极芯串能够具有一定大小的电压以满足工作需要，而多个极芯串有通过并联的方式进行连接，可以使多个极芯串的电容量进行叠加，从而使单体电池100具有较大的电容量，有利于延长单体电池100的供电时间。
进一步地，本申请实施例中，在金属壳体11和极芯组12之间还设有封装膜13，即极芯组12封装于封装膜13内。由此，通过封装膜13和金属壳体11可以实现对极芯组12的二次封装，有利于提高单体电池100的密封效果。可以理解的是，封装膜13内还注入有电解液。因此，通过上述方式，还可以避免电解液与金属壳体11的接触，避免金属壳体11的腐蚀或者电解液的分解。
其中，金属壳体11和封装膜13之间的气压低于金属壳体11外的气压，封装膜13内的气压低于金属壳体11与封装膜13之间的气压。
在本申请中，“气压”是大气压强的简称。是作用在单位面积上的大气压力，即等于单位面积上向上延伸到大气上界的垂直空气柱的重量。
金属壳体11和封装膜13之间的气压也即位于金属壳体11和封装膜13之间的空间内的气压，该气压低于金属壳体11外的气压，因此，本申请实施例中，金属壳体11和封装膜13之间为负压状态，由此金属壳体11在大气压的作用下发生凹陷或变形，则金属壳体11和极芯组12之间的间隙随之减小，极芯组12发生窜动或者相互之间发生位移的空间减小，进而可以减少极芯组12的窜动以及极芯组12之间的相对位移，提高单体电池100的稳定性，以及单体电池100的强度以及单体电池100安全性能。
例如，可以通过对金属壳体11和封装膜13之间的空间进行抽气处理，以使金属壳体11和封装膜13之间为负压状态，由此可以使得金属壳体11和内部的极芯组12尽量贴近，减少内部空隙，防止极芯在金属壳体内发生窜动，同时防止极芯之间发生相对位移，减少集流体破损、隔膜打皱、和活性材料脱落等情况的发生，提高整个单体电池100的机械强度，延长单体电池100的使用寿命，提高单体电池100的安全性能。
在一种实施方式中，金属壳体11和封装膜13之间的气压值为P1，P1的取值范围可以为-100Kpa至-5Kpa，进一步优选地，P1的取值可以是-75Kpa至-20Kpa。当然，本领域的技术人员可以根据实际需要设定P1的值。需要说明的是，金属壳体11和封装膜13之间也可以为真空状态。
进一步地，封装膜13内的气压值为P2，P2的取值范围可以为-100Kpa至-20Kpa。
其中，P1和P2的关系满足：P1＞P2，且P1/P2的范围为0.05-0.85。
将P1、P2以及P1/P2限定在上述范围内，本技术中的极芯组12采用二次密封的模式，先将电池极芯组12封装在封装膜13内，为避免封装膜13发生由于内部气压过大使封装膜13外鼓造成的破损，我们选择金属壳体11与封装膜13之间的气压大于封装膜13内的气压。同时，我们通过大量实验验证，当P1/P2在上述范围时，较好的保证了单体电池100二次密封的可靠性，同时，保证了单体电池100极片之间的界面，避免了极片间间隙，使锂离子能更好的传导。
本申请的一实施例中，封装膜13包括一个，串联的多个极芯组12封装在同一个封装膜13内，串联连接的两个极芯组12中的其中一个极芯组12的第一电极121和另一个极芯组12的第二电极122的连接处位于封装膜13内。也就是说，封装膜13一体设置，多个极芯组12封装在同一封装膜13内。
在实际应用中，例如，如图10所示，可以先将多个极芯组12进行串联，然后利用一整张封装膜13将串联的极芯组12包裹起来，比如可以将串联的极芯组12放置于封装膜13的一部分区域上(或者可以预先在封装膜13的一部分区域上开凹槽，然后将串联的多个极芯组12置于该凹槽内)，然后将封装膜13的另一部分区域朝向极芯组12的方向对折，之后通过热熔处理将两部分区域的封装膜13进行热熔密封，由此将串联的极芯组12封装在同一封装膜13内。
其中，封装膜13中与第一电极121和/或第二电极122相对的位置形成有封装部131以将相邻两极芯组主体123隔离，并且相邻两极芯组12中的其中一个极芯组12的第一电极121和另一个极芯组122的第二电极122中的至少之一位于封装部131内。通过封装部131将多个极芯组主体123之间隔离，避免多个极芯组12的电解液互相流通，多个极芯组12之间不会相互影响，且多个极芯组12中的电解液不会因电位差过大而分解，保证单体电池100的安全性和使用寿命。
封装部131可以有多种实施方式，例如可以采用扎带将封装膜13扎紧形成封装部131，也可以直接将封装膜13热熔融连接形成封装部131。或者是直接在两个极芯组12之间设置隔板以构成封装部131，封装部131的具体方式不作特殊限定。
本申请的另一实施例中，如图11所示，封装膜13含有多个，其中至少一个极芯组12封装于一个封装膜13内以形成极芯组件，多个极芯组件之间串联。
换句话说，封装膜13的数量与极芯组12的数量一一对应，每个极芯组12单独封装在一个封装膜13，该种实施方式，在多个极芯组12制备完成后，可在每个极芯组12外单独套一个封装膜13，然后多个极芯组件再串联。
其中，极芯组12的第一电极121和第二电极122中的至少一个延伸出封装膜13，例如可以是第一电极121延伸出封装膜13，或者也可以是第二电极122延伸出封装膜13，或者也可以是第一电极121和第二电极122都延伸出封装膜13。通过将至少一个第一电极121和/或第二电极122延伸出封装膜13，可以利用延伸出的电极与其他极芯组件进行串联。
在本申请实施例中，多个极芯组12的排列方向为第一方向AB，极芯组12的长度方向沿第一方向AB延伸，单体电池100的长度也沿第一方向AB延伸，即多个极芯组12沿着单体电池100的长度方向依次排列，且极芯组12的第一电极121和第二电极122沿第一方向AB分别位于极芯组12的两侧，即多个极芯组12采用“头对头”的排布方式，此排布方式可以较为方便地实现极芯组12之间的两两串联，连接结构简单。另外该种排布方式可以较为方便的制造长度较长的单体电池100，由此在将单体电池100安装进电池包外壳内时，可以不需要设置横梁和纵梁等支撑结构，而是利用单体电池100本身的金属壳体11作支撑而将单体电池100直接安装在电池包外壳上，由此可以节省电池包内部空间，提高电池包的体积利用率，且有利于降低电池包的重量。
通过在单体电池100内设置多个极芯组12，与现有只设置一个极芯的方式相比，可以更方便地制造出长度较长的单体电池100，传统的电池中，一旦电池较长，内部用作集流体的铜铝箔的长度即会相应增加，大大提高了电池内部的电阻，无法满足当前越来越高的功率及快充的要求。在电池长度相同的情况下，本申请实施例可以极大的减小电池内部的电阻，避免高功率输出、快充等情况下电池过热等带来的问题。
如图12所示，金属壳体11沿第二方向CD具有相对的两个第三表面1005，该第三表面1005也即单体电池100的最大表面，也即单体电池100的“大面”。其中，至少一个第三表面1005向金属壳体11内部凹陷，由此可以使得金属壳体11与极芯组12尽量贴合。
由于金属壳体11的厚度较小，其为较薄的薄片，因此金属壳体11的第三表面1005上 的凹陷114例如可以是通过对金属壳体11内进行抽气时所形成的凹陷。即在对金属壳体11和封装膜13之间的空间进行抽气处理以使得金属壳体11和封装膜13之间的气压低于金属壳体11外的气压时，随着抽气的进行，金属壳体11的第三表面1005容易向金属壳体11内形成凹陷114。
单体电池100在正常使用的过程中，由于材料本身的膨胀，电解液产气等原因电池通常会发生膨胀，而往往膨胀形变最大的区域在于电池的大面。采用本技术，将电池初始状态时大面通过抽真空限制在略微内陷的情况，可有效缓解电池膨胀后电池之间的挤压，提高电池及整个系统的寿命、安全等性能。
在其他一些实施例中，如图12所示，也可以是预先在金属壳体11的第三表面1005上形成凹陷后，再对金属壳体11内进行抽气处理。其中，金属壳体11的第三表面1005上的凹陷114可以有多个，例如，预先在第三表面1005上形成多个凹陷114，每个凹陷114的位置与一个极芯组12所在的位置对应。
其中，在一些实施方式中，金属壳体11相对的两个第三表面1005上均向内部凹陷，以通过凹陷的区域夹持极芯组12。
其中，可以在金属壳体11上设置排气孔，通过该排气孔对金属壳体11和封装膜13之间的空间进行抽气操作。其中，需要对该排气孔进行密封处理，因此在排气孔内还设置有密封件，以密封排气孔。该密封件例如可以是堵头、橡胶件等，对此不做限定。
在一些实施方式中，金属壳体11在抽气之前，极芯组12与金属壳体11的内表面之间设有间隙；该间隙便于极芯组12比较方便的装入到金属壳体11内部；在对金属壳体11抽气之后，金属壳体11沿第二方向按压在极芯组12的外表面以夹持所述极芯组12，从而减小极芯组12在金属壳体11内部窜动的空间，提高单体电池100的安全性能。
本申请实施例中，金属壳体11的强度高，散热效果好，金属壳体11可以包括但不限于铝壳、或钢壳。在一些实施例中，金属壳体11的厚度为0.05mm-1mm。
金属壳体11的厚度较厚不仅会增加单体电池100的重量，降低单体电池100的容量，而且金属壳体11厚度过厚，在大气压的作用下，金属壳体11不容易向极芯组12一侧凹陷或变形，无法减少金属壳体11和极芯组12之间的间距，进而无法有效的对极芯组12实现定位的作用。不仅如此，金属壳体11过厚，会增加抽气的成本，从而增加制造成本。
本申请将金属壳体11厚度限定为上述范围内，不仅能保证金属壳体11强度，而且也不会降低单体电池100的容量，还可以在负压的状态下，金属壳体11更加容易的发生变形，减少金属壳体11和极芯组12之间的间距，从而减少极芯组12在金属壳体11内部的窜动以及极芯组12之间的相对位移。
本申请的实施例中，封装膜13包括层叠的非金属外层膜和非金属内层膜，内层膜位于外层膜和极芯组12之间。
内层膜具有较好的化学稳定性，例如可以采用具有抗电解液腐蚀特性的材料，比如可以是聚丙烯(PP，Polypropylene)、聚乙烯(PE，Polyethylene)或者聚对苯二甲酸乙二酯(PET，Polyethylene terephthalate)，或者可以是上述材料中的多种组合。
外层膜为防护层，利用外层膜可以阻止空气尤其是水汽、氧等渗透，其材料例如可以采用聚对苯二甲酸乙二酯、聚酰胺(PA，Polyamide)或聚丙烯，或者可以是上述材料的多种组合。
本实施例的封装膜13中，外层膜的熔点大于内层膜的熔点，从而可以在热熔密封时，外层膜不会被熔融，而内层膜能够及时熔融以保证密封性能的优良。进一步地，外层膜和内层膜的熔点差的范围为30℃-80℃，如两者熔点差可以是50℃或70℃等，具体的材料选择可以根据实际需要而定。
其中，非金属外层膜和非金属内层膜之间采用胶黏剂粘结复合。例如，外层膜的材料可以是PP，内层膜的材料可以是PET，两者粘结的粘结剂例如可以是聚烯烃类粘结剂，以粘结形成复合膜。
本实施例通过采用双层非金属膜形成封装膜13对极芯组12进行封装，由于采用非金属的封装膜13，具有更高的拉伸强度和断裂伸长率，可以减少对单体电池100厚度的限制，使得生产得到的单体电池100具有更大的厚度。其中，本实施例的单体电池100的厚度可扩展范围大，如可以大于10mm，例如可以在13-75mm的范围。
在本申请的一些实施方式中，封装膜13可以为铝塑膜。
本申请的一个实施例中，单体电池100为锂离子电池。
本申请实施例中，同一电池单元21中，沿第二方向CD依次排列的单体电池中，两个相邻的单体电池100之间具有间隙，该间隙与单体电池100的厚度的比例范围为0.001-0.15。
需要说明的是，两个相邻电池的间隙会随着电池的工作时间的增加而有所变化，但无论是处于工作中还是工作后或者是电池出厂前，只要满足电池之间的间隙与厚度的比例范围在本申请限定的范围内，均落在本申请的保护范围内。
本申请通过在单体电池100之间预留的一定的间隙，可以给单体电池100的膨胀预留缓冲空间。
单体电池100的膨胀与单体电池100的厚度相关，电池的厚度越大，单体电池100越容易发生膨胀，本申请将单体电池100之间的间隙与单体电池100的厚度的比值限定在0.001-0.15，既可以充分利用电池包200的空间，提高电池包200的利用率，同时也可以给单体电池100的膨胀起到较好的缓冲效果。
另外，单体电池100膨胀时会产生热量，单体电池100之间预留一定的间隙，该间隙还可以充当散热通道，例如风道，单体电池100面积较大的面散热效果更好，因而还可以提高电池包200的散热效率，提供电池包200的安全性能。
在上述方案中，单体电池100之间的间隙可以理解为单体电池100之间不设置任何结构件，单纯预留一定的空间，也可以理解单体电池100设置其他结构件使单体电池100与单体电池100之间通过该结构件隔开。
需要说明的是，当单体电池100之间设置结构件，单体电池100之间的间隙应该理解为该结构件两侧的单体电池100之间的距离，而不能理解该结构件与单体电池100之间的间距。
应当说明的是，结构件可以与该结构件两侧的单体电池100之间可以预留一定的间隙也可以直接接触，当结构件与位于两侧的单体电池100直接接触时，结构件应当具有一定的柔性，可以为单体电池100的膨胀起到缓冲作用。作为结构件包括但不限于气凝胶，导热结构胶或者是隔热棉。
本申请还提供一种包括上述电池包200的电动车，电动车与上述的电池包200相对于相关技术所具有的优势相同，此处不再赘述。
在本申请的描述中，需要说明的是，除非另有明确的规定和限定，术语“安装”、“相连”、“连接”应做广义理解，例如，可以是固定连接，也可以是可拆卸连接，或一体地连接；可以是机械连接，也可以是电连接；可以是直接相连，也可以通过中间媒介间接相连，可以是两个元件内部的连通。对于本领域的普通技术人员而言，可以具体情况理解上述术语在本申请中的具体含义。
在本说明书的描述中，参考术语“实施例”、“具体实施例”、“示例”等的描述意指结合该实施例或示例描述的具体特征、结构、材料或者特点包含于本申请的至少一个实施例或示例中。在本说明书中，对上述术语的示意性表述不一定指的是相同的实施例或示例。而且，描述的具体特征、结构、材料或者特点可以在任何的一个或多个实施例或示例中以合适的方式结合。
尽管已经示出和描述了本申请的实施例，本领域的普通技术人员可以理解：在不脱离本申请的原理和宗旨的情况下可以对这些实施例进行多种变化、修改、替换和变型，本申请的范围由权利要求及其等同物限定。

Claims (15)

  1. 一种电池包，用于为车辆提供电能，其特征在于，包括至少一个电池单元，所述电池单元包括至少一个电池串，所述电池串含有一个或至少两个单体电池，所述电池串两端的电压差小于或等于60V；
    当所述电池串中含有至少两个单体电池时，所述电池串中的单体电池沿第一方向依次排列，所述第一方向与车辆车尾到车头的方向平行。
  2. 根据权利要求1所述的电池包，其特征在于，所述电池串两端的电压差小于或等于45V。
  3. 根据权利要求2所述的电池包，其特征在于，所述电池串两端的电压差为20～40V。
  4. 根据权利要求1-3中任一项所述的电池包，其特征在于，所述电池单元包括多个所述电池串，多个所述电池串沿第二方向依次排列，所述第二方向为车辆的宽度方向。
  5. 根据权利要求4所述的电池包，其特征在于，所述电池串之间为串联和/或并联。
  6. 根据权利要求1所述的电池包，其特征在于，当所述电池串中含有至少两个单体电池时，所述电池串中的单体电池之间为串联。
  7. 根据权利要求1所述的电池包，其特征在于，所述单体电池的长度沿第一方向延伸。
  8. 根据权利要求7所述的电池包，其特征在于，所述单体电池包括第一极柱和第二极柱，且所述单体电池沿第一方向具有相对的两个第一表面；
    所述第一极柱和第二极柱位于单体电池的同一个所述第一表面上，或者分别位于单体电池的两个第一表面上。
  9. 根据权利要求1所述的电池包，其特征在于，所述单体电池包括第一极柱和第二极柱，所述单体电池具有面对车辆顶部的第二表面，所述第一极柱和第二极柱位于所述第二表面上。
  10. 根据权利要求1所述的电池包，其特征在于，所述电池单元有多个，所述电池单元之间为串联。
  11. 根据权利要求10所述的电池包，其特征在于，多个电池单元呈阵列排列以形成电池单元阵列，所述电池单元阵列包括多排电池单元组，多排电池单元组沿第一方向依次排列，分别位于相邻两排电池单元组且相互电连接的两个电池单元之间，连接有主动安全装置。
  12. 根据权利要求11所述的电池包，其特征在于，所述主动安全装置为继电器或保险丝。
  13. 如权利要求1所述的电池包，其特征在于，至少一个所述单体电池的长度与所述车辆的长度的比值范围为0.2-0.8。
  14. 如权利要求1所述的电池包，其特征在于，所述单体电池100的长度范围为600mm-2500mm。
  15. 一种电动车，其特征在于，包括权利要求1-14任一项所述的电池包。
PCT/CN2021/074132 2020-02-28 2021-01-28 电池包及电动车 WO2021169721A1 (zh)

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