WO2020134747A1 - 电池模组以及电池包 - Google Patents

电池模组以及电池包 Download PDF

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Publication number
WO2020134747A1
WO2020134747A1 PCT/CN2019/119941 CN2019119941W WO2020134747A1 WO 2020134747 A1 WO2020134747 A1 WO 2020134747A1 CN 2019119941 W CN2019119941 W CN 2019119941W WO 2020134747 A1 WO2020134747 A1 WO 2020134747A1
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WIPO (PCT)
Prior art keywords
battery module
battery
side wall
electrode
gap
Prior art date
Application number
PCT/CN2019/119941
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English (en)
French (fr)
Inventor
金海族
史东洋
李振华
陈兴地
陈宁
胡飞
Original Assignee
宁德时代新能源科技股份有限公司
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Publication of WO2020134747A1 publication Critical patent/WO2020134747A1/zh

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/04—Construction or manufacture in general
    • H01M10/0481—Compression means other than compression means for stacks of electrodes and separators
    • 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
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/04—Construction or manufacture in general
    • H01M10/0472—Vertically superposed cells with vertically disposed plates
    • 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
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • H01M10/0587—Construction or manufacture of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/102—Primary casings; Jackets or wrappings characterised by their shape or physical structure
    • H01M50/103—Primary casings; Jackets or wrappings characterised by their shape or physical structure prismatic or rectangular
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/116—Primary casings; Jackets or wrappings characterised by the material
    • H01M50/117—Inorganic material
    • H01M50/119—Metals
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/131—Primary casings; Jackets or wrappings characterised by physical properties, e.g. gas permeability, size or heat resistance
    • H01M50/133—Thickness
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/147—Lids or covers
    • 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
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/04—Construction or manufacture in general
    • H01M10/0463—Cells or batteries with horizontal or inclined electrodes
    • 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
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present application relates to the technical field of batteries, in particular to a battery module and a battery pack.
  • Secondary batteries are also called power batteries and are rechargeable batteries. Secondary batteries are widely used. Low-capacity secondary batteries can be used for small electric vehicles, and high-capacity secondary batteries can be used for large electric vehicles, such as hybrid cars or electric cars.
  • the secondary batteries are used in groups, it is necessary to use a bus bar to connect each secondary battery in series or in parallel. Usually the bus bar is welded to the positive and negative electrodes of the secondary battery.
  • the battery module includes a plurality of secondary batteries and connectors for fixing the plurality of secondary batteries.
  • the secondary battery mainly includes a case, an electrode assembly, and a top cover assembly.
  • the electrode assembly is formed by winding or stacking the positive pole piece, the negative pole piece and the separator.
  • the electrode assembly included in the secondary battery expands itself, thereby releasing a large expansion force to the outside.
  • the expansion forces released by the electrode assemblies included in the multiple secondary batteries are superimposed A larger resultant force will be formed, which will not only cause the deterioration of the electrical performance of the secondary battery, but also require the connector to have a high structural strength to restrain the expansion force, which needs to be achieved by increasing the volume of the connector, which in turn reduces
  • the energy density and space utilization of the secondary battery are also included.
  • an embodiment of the present application provides a battery module, including:
  • the secondary battery includes a case, an electrode assembly, and a closed portion;
  • the case includes an accommodating hole having an opening, the accommodating hole extends in a second direction, the first direction and the second direction intersect, the closing portion is sealedly connected with the housing to cover the opening, and the electrode assembly is disposed in the accommodating hole and includes more than two
  • the electrode unit includes a first pole piece, a second pole piece and a separator, and two or more electrode units are stacked in the second direction.
  • the electrode unit includes a wide face and a narrow face.
  • the wide face is disposed opposite to the closed portion.
  • the narrow face is located on one side of the wide face along the first direction.
  • the area of the wide face is larger than that of the narrow face.
  • the ratio of the area of the narrow surface to the area of the wide surface is 1/10 to 1/2.
  • the first pole piece, the second pole piece, and the separator are wound to form an electrode unit
  • the electrode unit has a flat structure, and includes two wide faces and two narrow faces, and the two narrow faces are connected On opposite sides of the wide surface in the first direction.
  • first gap corresponding to the position of the narrow surface between the first pole pieces of two adjacent circles, and the size of the first gap is 5um to 50um.
  • first gap corresponding to a narrow surface position and a second gap corresponding to a wide surface position between two adjacent first pole pieces, and the size of the first gap is larger than that of the second gap size.
  • the material of the housing is a metal material
  • the housing includes a first side wall, a second side wall, and a bottom wall connected to the first side wall and the second side wall, the first side wall The area of is larger than the area of the second side wall and the bottom wall, the first side wall of two adjacent secondary batteries is oppositely arranged, and the narrow surface is set correspondingly to the first side wall.
  • the thickness of the first side wall and the second side wall are both smaller than the thickness of the bottom wall.
  • the closing portion includes a top cover plate and an electrode terminal, the top cover plate and the electrode terminal are located on one side of the electrode assembly along the second direction, the top cover plate is connected to the case, and the electrode terminal is disposed on the top
  • the cover plate is also electrically connected to the electrode assembly.
  • the battery module further includes a first end plate and a second end plate, the first end plate and the second end plate are spaced apart along the first direction, and two or more secondary batteries are provided on the first Between one end plate and the second end plate, the Young's modulus of the first end plate and the second end plate is less than 30Gpa.
  • the battery module according to the embodiment of the present application includes more than two secondary batteries arranged side by side along the first direction.
  • the electrode units included in each secondary battery are stacked in the second direction of the housing hole of the case. When the electrode unit expands, it mainly expands and deforms in the second direction of the receiving hole, while the expansion amount in the first direction is small. In this way, the cumulative expansion force of each secondary battery in the first direction is small.
  • the battery module does not need to use a structural member with higher strength to restrain the expansion force or use a lower strength structural member to restrain the expansion force, thereby effectively reducing the overall mass of the battery module, so that
  • the battery module itself has a more compact structure, which effectively improves the energy density of the battery module.
  • the battery module itself has a small expansion in the first direction, which can effectively improve the safety of the use process.
  • an embodiment of the present application provides a battery pack, including: a box body having a containing chamber; as in the battery module of the above embodiment, the battery module is contained in the containing chamber.
  • the height of the case is greater than twice the height of the secondary battery and less than twice the height of the secondary battery.
  • the battery pack includes 2 to 6 battery modules arranged along the width direction of the case, and each battery module includes 20 to 32 secondary batteries.
  • the thickness of the secondary battery is greater than or equal to 50 mm, and the height of the secondary battery is greater than or equal to 80 mm.
  • FIG. 1 is a schematic structural diagram of a battery module according to an embodiment of the present application.
  • FIG. 2 is a schematic diagram of an exploded structure of a secondary battery according to an embodiment of the present application.
  • FIG. 3 is a schematic structural diagram of an electrode unit according to an embodiment of the present application.
  • FIG. 4 is a schematic cross-sectional structural view of a secondary battery according to an embodiment of the present application.
  • FIG. 5 is an enlarged view at A in FIG. 4;
  • FIG. 6 is a schematic diagram of an exploded structure of a battery pack according to an embodiment of the present application.
  • FIG. 7 is a schematic diagram of the overall structure of a battery pack according to an embodiment of the present application.
  • Housing 12a, receiving hole; 121, first side wall; 122, second side wall; 123, bottom wall;
  • Electrode unit; 14a wide face; 14b, narrow face; 141, first pole piece; 142, second pole piece; 143, diaphragm;
  • Top cover assembly 151, top cover plate; 152, electrode terminal;
  • X first direction
  • Y second direction
  • connection should be understood in a broad sense, for example, it can be a fixed connection or a Disconnected, or integrally connected; either directly connected or indirectly connected through an intermediary.
  • connection should be understood in a broad sense, for example, it can be a fixed connection or a Disconnected, or integrally connected; either directly connected or indirectly connected through an intermediary.
  • an embodiment of the present application provides a battery module 10 including: two or more secondary batteries 11 of this embodiment and a bus bar for connecting two secondary batteries 11.
  • Two or more secondary batteries 11 are arranged side by side along the first direction X, where the first direction X is the arrangement direction of the two or more secondary batteries 11.
  • One end of the bus bar is connected and fixed to one of the two secondary batteries 11, and the other end is connected and fixed to the other secondary battery 11.
  • the secondary battery 11 of this embodiment may be a hard case battery or a soft pack battery.
  • the secondary battery 11 includes a case 12, an electrode assembly 13 provided in the case 12, and a closed portion that is sealingly connected to the case 12.
  • the housing 12 of the embodiment of the present application may be in the shape of a quadrangular prism or other shapes.
  • the case 12 has an internal space that accommodates the electrode assembly 13 and the electrolyte.
  • the housing 12 may be made of materials such as aluminum, aluminum alloy, or plastic.
  • the electrode assembly 13 of the embodiment of the present application includes more than two electrode units 14.
  • the electrode unit 14 of the embodiment of the present application may form the main body part and the tab connected to the main body part by stacking or winding the first pole piece 141, the second pole piece 142 and the separator 143 together.
  • the diaphragm 143 is an insulator between the first pole piece 141 and the second pole piece 142.
  • the electrode unit 14 of the embodiment of the present application is formed by winding a separator 143, a first pole piece 141, and a second pole piece 142, and the electrode unit 14 has a multi-turn flat structure.
  • the first pole piece 141 is used as the positive pole piece, and the second pole piece 142 is used as the negative pole piece.
  • the first pole piece 141 may also be a negative pole piece, and the second pole piece 142 is a positive pole piece.
  • the positive electrode active material is coated on the coating area of the positive electrode sheet, and the negative electrode active material is coated on the coating area of the negative electrode sheet.
  • a plurality of uncoated areas extending from the main body portion are used as the tabs.
  • the electrode unit 14 includes two tabs, namely a positive tab and a negative tab.
  • the positive tab is composed of a plurality of uncoated tabs extending from the coated area of the positive tab
  • the coating regions are stacked;
  • the negative electrode ear is formed by stacking a plurality of uncoated regions extending from the coating region of the negative electrode sheet.
  • the active material layer included in the electrode unit 14 of the embodiment of the present application will swell, causing the entire electrode unit 14 to swell.
  • the capacity of the electrode unit of the embodiment of the present application is 50 Ah to 300 Ah.
  • the closing portion in the embodiment of the present application may be an aluminum-plastic film formed of aluminum alloy, plastic, nylon, or the like, or may be a top cover assembly 15 formed of a metal or other material.
  • the closed portion of the embodiment of the present application is the top cover assembly 15, wherein the top cover assembly 15 includes a top cover plate 151 and an electrode terminal 152.
  • the top cover plate 151 and the electrode terminal 152 are both located on the side of the electrode assembly 13 along the second direction Y.
  • the height direction of the secondary battery 11 is the same as the second direction Y.
  • the height direction of the housing 12 is the same as the second direction Y.
  • the top cover assembly 15 is hermetically connected to the housing 12 through the top cover plate 151.
  • the electrode terminal 152 is provided on the top cover plate 151 and electrically connected to the electrode assembly 13.
  • the battery module 10 of the embodiment of the present application includes more than two secondary batteries 11. Two or more secondary batteries 11 are arranged side by side along the first direction X.
  • the secondary battery 11 includes a case 12 having an accommodating hole 12a and an electrode assembly 13 provided in the accommodating hole 12a, wherein the accommodating hole 12a has an opening and extends along the second direction Y, that is, the second direction Y and the accommodating hole 12a The direction of extension is parallel.
  • the electrode assembly 13 includes more than two electrode units 14. Two or more electrode units 14 are stacked in the second direction Y, wherein the second direction Y is parallel to the stacking direction of the two or more electrode units 14.
  • the second direction Y and the first direction X are perpendicular to each other, and the second direction Y is also perpendicular to the opening and the closing portion of the receiving hole 12a. It is easy to understand that the second direction Y of the embodiment of the present application may also intersect and be nearly perpendicular to the first direction X, and the second direction Y of the embodiment of the present application may also intersect and be nearly perpendicular to the opening and the closing portion of the accommodating hole 12a.
  • the electrode assembly 13 has a first expansion force along the first direction X and a second expansion force along the second direction Y.
  • the first expansion The force is less than the second expansion force. Therefore, the electrode assembly 13 mainly expands in the second direction Y, so that the expansion force of the electrode assembly 13 mainly follows the second direction Y, while in the first direction X, the first expansion force is small, so the housing 12 The impact is less.
  • the second expansion force generated when each secondary battery 11 expands intersects the first direction X, that is, each of the two The direction of the second expansion force generated when the secondary battery 11 expands is along the second direction Y, so the second expansion force generated by each secondary battery 11 does not accumulate in the first direction X and form a large resultant force.
  • the rigidity and strength of the fixing member itself are lower, which is beneficial to reduce
  • the volume or weight of the small fixing member is beneficial to improve the energy density and space utilization ratio of the secondary battery 11 and the battery module 10 as a whole; Furthermore, it is beneficial to improve the cycle performance of the secondary battery.
  • the electrode unit 14 in the embodiment of the present application includes a wide surface 14a and a narrow surface 14b, wherein the wide surface 14a is disposed opposite to the closed portion, and here, the wide surface 14a and the surface of the closed portion facing the wide surface 14a are not strictly defined
  • the complete opposite of the two also includes the relative arrangement when the two parts are arranged oppositely or when the wide surface 14a is arched due to expansion and when the surface of the closed portion facing the wide surface 14a is flat.
  • the narrow surface 14b is located on one side of the wide surface 14a along the first direction X.
  • the wide surface 14a has opposite sides along the first direction X, and one narrow surface 14b is connected to one side of the wide surface 14a.
  • the area of the wide surface 14a is larger than the area of the narrow surface 14b. Since the area of the wide surface 14a is larger than the area of the narrow surface 14b, the expansion force generated by the wide surface 14a is larger than that of the narrow surface 14b, thereby further reducing the expansion force of the secondary battery 11 in the first direction X.
  • the ratio of the area of the narrow surface 14b to the area of the wide surface 14a is 1/10 to 1/2. When the ratio of the two is greater than 1/2, the area of the narrow surface 12b is larger at this time.
  • the total force of the swelling force is large; when the ratio of the two is less than 1/10, at this time, in the case of the same capacity of the secondary battery 11, the area of the wide surface 14a is too large, which makes it difficult to infiltrate the electrolyte.
  • the electrode unit 14 of the embodiment of the present application is preferably formed by winding a first pole piece 141, a second pole piece 142 and a separator 143.
  • the electrode unit 14 of the embodiment of the present application has a flat structure.
  • the electrode unit 14 includes two opposite winding end surfaces and a winding axis perpendicular to the winding end surface.
  • the electrode unit 14 includes a wide surface 14a and a narrow surface 14b.
  • the narrow surface 14b includes at least part of the arc area, and the number of the wide surface 14a and the number of the narrow surface 14b are both two.
  • the two wide surfaces 14a are oppositely arranged along the second direction Y, and each wide surface 14a is perpendicular to the second direction Y, while the two narrow surfaces 14b are oppositely arranged along the first direction X and are respectively connected to the two wide surfaces 14a Opposite sides of X in one direction.
  • the wide surface 14 a and the narrow surface 14 b are alternately arranged around the winding axis of the electrode unit 14.
  • the wide surfaces 14a of the two adjacent electrode units 14 are in contact with each other.
  • both the wide surface 14a and the narrow surface 14b will expand.
  • the wide surface 14a expands in the second direction Y and the expansion of the wide surface 14a is greater than the expansion of the narrow surface 14b.
  • the wide surface 14a is a flat surface
  • the narrow surface 14b is an arc-shaped surface.
  • the wound electrode unit 14 of the embodiment of the present application forms a multilayer first pole piece 141 in its radial direction.
  • There is a first gap 16 corresponding to the position of the narrow surface 14b between the two adjacent turns of the first pole piece 141.
  • the size L1 of the first gap 16 and the size L2 of the second gap 17 both refer to the sum of the gap between the diaphragm 143 and the first pole piece 141 and the gap between the diaphragm 143 and the second pole piece 142.
  • each layer of the first pole piece 141 will be displaced in the radial direction of the electrode unit 14, Both the first gap 16 and the second gap 17 can absorb the displacement of each layer of the first pole piece 141, thus effectively reducing the expansion displacement of the narrow surface 14b and the wide surface 14a of the electrode unit 14, thereby effectively reducing the electrode unit 14
  • the size L1 of the first gap 16 is larger than the size L2 of the second gap 17, so that the first gap 16 can absorb a larger amount of expansion displacement of the first pole piece 141 relative to the second gap 17, so that the electrode unit
  • the expansion displacement of the narrow surface 14b of 14 is smaller than the expansion displacement of the wide surface 14a of the electrode unit 14, thereby reducing the accumulation of expansion force in the first direction X to a greater extent.
  • the first gap 16 and the second gap 17 are formed by the same gap between the two turns of the first pole piece 141.
  • the size L1 of the first gap 16 is 5um to 50um.
  • the narrow surface 14b of the electrode unit 14 When the size L1 of the first gap 16 is less than 5um and the electrode unit 14 expands, the narrow surface 14b of the electrode unit 14 will contact the case 12 earlier, so that the electrode unit 14 continues after the narrow surface 14b contacts the case 12 When it expands, it will receive a large reaction force, and the electrolyte in the first gap 16 will be squeezed out, resulting in the lithium ions cannot be transmitted normally, affecting the service life of the secondary battery 11. At the same time, since the narrow surface 14b of the electrode unit 14 is constrained by the housing 12, the expansion force is transferred to the wide surface 14a, causing the expansion force to accumulate excessively in the first direction X.
  • the size L1 of the first gap 16 is greater than 50um, the first gap 16 between two adjacent first pole pieces 141 will be too large, resulting in a long lithium ion transmission time, resulting in poor dynamic performance of the narrow surface 14b , Prone to lithium precipitation.
  • the material of the housing 12 in the embodiment of the present application is preferably a metal material.
  • the housing 12 includes a first side wall 121, a second side wall 122 and a bottom wall 123 connected to the first side wall 121 and the second side wall 122.
  • the top cover assembly 15 is provided corresponding to the bottom wall 123 along the second direction Y.
  • the top cover assembly 15 is hermetically connected to the first side wall 121 and the second side wall 122.
  • the area of the first side wall 121 is larger than the area of the second side wall 122 and also the area of the bottom wall 123.
  • the first side walls 121 of two adjacent secondary batteries 11 are oppositely arranged. Referring to FIG. 4 or FIG.
  • the narrow surface 14b is provided corresponding to the first side wall 121.
  • the narrow surface 14b of the electrode unit 14 may also expand, but the amount of expansion is small, and the compressive stress applied to the first side wall 121 is small, so that each secondary battery 11 is exposed in the first direction X
  • the accumulated expansion force is relatively small, and because the area of the first side wall 121 is large, the degree of deformation of the first side wall 121 can be reduced.
  • the electrode unit 14 consumes its own electrolyte during use. Therefore, it is necessary to constantly replenish the electrolyte from the outside.
  • the first side wall 121 can restrain the narrow surface 14b, so that the first gap 16 becomes smaller, which makes it difficult for the electrolyte in the housing 12 to be replenished to the electrode through the first gap 16 Inside the unit 14, the electrical performance of the electrode unit 14 is affected.
  • the first pole piece 141 or the second pole piece 142 located at the outermost layer will be subjected to a large tensile stress, thereby easily causing the first pole piece 141 or the second pole piece 142 to break.
  • the first side wall 121 of the embodiment of the present application can restrain the narrow surface 14b and prevent the narrow surface 14b from expanding too much, thereby effectively reducing the possibility of the first pole piece 141 or the second pole piece 142 breaking.
  • the number of the first side wall 121 and the second side wall 122 are both two.
  • the first side wall 121 and the second side wall 122 are alternately arranged so as to be configured as a cylindrical structure having a rectangular cross section.
  • the bottom wall 123 has a rectangular plate-like structure, and is hermetically connected to the first side wall 121 and the second side wall 122.
  • the size L3 of the third gap 18 is 0.3 mm to 0.9 mm.
  • the size L3 of the third gap 18 is less than 0.3 mm, when the narrow surface 14b of the electrode unit 14 expands to a lesser extent, it will completely invade the third gap 18 and contact the first side wall 121 and apply pressure to the first side wall 121 Stress, so that when the narrow surface 14b of the electrode unit 14 reaches the maximum expansion amount, the stress exerted by the electrode unit 14 on the first side wall 121 may be excessive, which may cause the first side wall 121 to deform or cause the entire battery module 10 The deformation occurs in the first direction X.
  • the narrow surface 14 b of the electrode unit 14 can only fully invade the third gap 18 and come into contact with the first side wall 121 when the expansion of the narrow surface 14 b of the electrode unit 14 is large, resulting in the first side wall 121
  • the electrode unit 14 cannot be effectively restrained, and the first electrode piece 141 or the second electrode piece 142 of the outermost layer of the electrode unit 14 may be broken due to the excessive expansion of the narrow surface 14b of the electrode unit 14.
  • the thickness of the first side wall 121 and the second side wall 122 are both smaller than the thickness M of the bottom wall 123. Since the main expansion direction of the electrode unit 14 in the embodiment of the present application is along the second direction Y, when the electrode unit 14 expands, the electrode unit 14 applies a force to the bottom wall 123 relative to the first side wall 121 and the second side wall 122 The stress is greater. Increasing the thickness M of the bottom wall 123 can enhance the strength of the bottom wall 123 and improve the restraint performance of the electrode unit 14 and its own anti-deformation performance.
  • the bottom wall 123 restricts the expansion amount of the electrode unit 14, so that the expansion amount of the electrode unit 14 is not excessive, so that the first gap 16 does not It will be completely squeezed and occupied to disappear, ensuring that the electrolyte in the first gap 16 is sufficient.
  • reducing the thickness of the first side wall 121 and the second side wall 122 is beneficial to reduce the weight of the secondary battery 11 as a whole, thereby contributing to improving the energy density of the secondary battery 11 and the battery module 10.
  • the battery module 10 of the embodiment of the present application further includes a first end plate 19 and a second end plate 20.
  • the first end plate 19 and the second end plate 20 are spaced apart along the first direction X.
  • Two or more secondary batteries 11 are provided between the first end plate 19 and the second end plate 20.
  • the Young's modulus of the first end plate 19 and the second end plate 20 are both less than 30 Gpa.
  • the thickness of the first end plate 19 and the second end plate 20 in the first direction X may be The design is smaller, and its own stiffness and strength requirements are also lower, which is conducive to reducing the weight of the first end plate 19 and the second end plate 20, and is conducive to improving the energy density of the secondary battery 11 and the battery module 10, while It also reduces the restrictions on the materials of the first end plate 19 and the second end plate 20, and the material selection is more extensive, which reduces the difficulty and cost of manufacturing.
  • the battery module 10 further includes a connector that is simultaneously connected to the first end plate 19 and the second end plate 20. The connecting member can tighten the first end plate 19 and the second end plate 20, thereby tightening each secondary battery 11, and improving the position stability of each secondary battery 11.
  • the battery module 10 of the embodiment of the present application includes more than two secondary batteries 11 arranged side by side along the first direction X.
  • the electrode units 14 included in each secondary battery 11 are stacked in the second direction Y.
  • the electrode unit 14 of the embodiment of the present application expands, it mainly expands and deforms in the second direction Y, and the amount of expansion in the first direction X is small. In this way, the cumulative expansion force of each secondary battery 11 in the first direction X is small.
  • the battery module 10 does not need to use a structural member with higher strength to restrain the expansion force or use a structural member with a lower strength to restrain the expansion force, thereby effectively reducing the overall battery module 10
  • the quality makes the structure of the battery module 10 more compact and effectively improves the energy density of the battery module 10.
  • the battery module 10 itself has a smaller expansion in the first direction X, which can effectively improve the safety during use.
  • an embodiment of the present application further provides a battery pack 30.
  • the battery pack 30 can be applied to vehicles such as automobiles.
  • the car has a storage box that contains the battery pack 30, and the storage box is generally located at the bottom of the car, and the chassis of the car is closer to the ground, and the height of the storage box determines the height space of the car. Therefore, in order to reduce The height space of the car requires that the accommodating box be lengthened in the length or width direction of the car, and the length of the battery pack 30 and the battery module 10 will be lengthened accordingly.
  • the expansion force in the length direction is corresponding To increase, this requires that the battery pack 30 not only reduces the space occupied by the vehicle in the height direction, but also prevents the expansion force in the longitudinal direction from being too large.
  • the height direction of the car is parallel to the second direction Y, and one of the length direction or the width direction of the car is the same as the first direction X.
  • the battery pack 30 of the embodiment of the present application includes a case 31 and the battery module 10 of the above-mentioned embodiment disposed in the case 31.
  • the number of battery modules 10 may be one, or two or more.
  • the case 31 of the embodiment of the present application has a storage chamber 31 a for storing the battery module 10.
  • the box 31 includes an upper cover 311 and a bottom case 312.
  • the upper cover 311 and the bottom case 312 can be hermetically connected to seal the battery module 10 within the accommodating chamber 31a.
  • the battery module 10 accommodated in the accommodation chamber 31 a can be connected and fixed to the bottom case 312.
  • the height N of the case 31 is more than double the height H of the secondary battery 11 and less than twice the height H of the secondary battery 11, wherein the height direction of the case 31 is the same as the second direction Y .
  • a gap is reserved between the case 31 and each secondary battery 11 of the battery module 10.
  • the battery pack 30 includes two to six battery modules 10 arranged in the width direction of the case 31.
  • Each battery module 10 includes 20 to 32 secondary batteries 11.
  • the width direction of the box 31 is perpendicular to the first direction X and the second direction Y, and the length direction of the box 31 is the same as the first direction X. Since the amount of expansion of the secondary battery 11 of the embodiment of the present application in the first direction X is small, more secondary batteries 11 can be arranged side by side in the first direction X, thereby greatly improving the energy of the battery module 10 density.
  • the thickness D of the secondary battery 11 (see FIG. 1) is 50 mm or more.
  • the height H of the secondary battery 11 (see FIG. 4) is 80 mm or more.
  • the thickness direction of the secondary battery 11 is the same as the first direction X.
  • the height direction of the secondary battery 11 is the same as the second direction Y.
  • the battery pack 30 of the embodiment of the present application includes a case 31 and a battery module 10.
  • the battery module 10 expands, the amount of expansion of the battery module 10 in the longitudinal direction of the casing 31 is small, so that the expansion force released by the battery module 10 in the longitudinal direction is small, and the stress applied to the casing 31 is relatively small. small.
  • the first direction X there is no need to use a structural member with higher structural strength to constrain the battery module 10, which is beneficial to reduce the volume and weight of the structural member, thereby facilitating the lightweight design of the battery pack 30 and improving the battery pack 30 energy density.
  • the box 31 does not need to have strong rigidity and strength in the first direction X, reducing the structural requirements of the box 31.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Inorganic Chemistry (AREA)
  • Battery Mounting, Suspending (AREA)
  • Sealing Battery Cases Or Jackets (AREA)

Abstract

一种电池模组(10)以及电池包(30)。电池模组(10)包括：两个以上的二次电池(11)，两个以上的二次电池(11)沿第一方向(X)并排设置，二次电池(11)包括壳体(12)、电极组件(13)以及封闭部，壳体(12)包括具有开口的容纳孔(12a)，容纳孔(12a)沿第二方向(Y)延伸，第一方向(X)和第二方向(Y)相交，封闭部与壳体(12)密封连接以盖闭开口，电极组件(13)设置于容纳孔(12a)内并且包括两个以上的电极单元(14)，电极单元(14)包括第一极片(141)、第二极片(142)和隔膜(143)，两个以上的电极单元(14)沿第二方向(Y)层叠设置。所述电池模组(10)自身在二次电池(11)排列方向上的膨胀量较小，能够有效提升使用过程安全性。

Description

电池模组以及电池包
相关申请的交叉引用
本申请要求享有于2018年12月29日提交的名称为“电池模组以及电池包”的中国专利申请201811646277.6的优先权，该申请的全部内容通过引用并入本文中。
技术领域
本申请涉及电池技术领域，特别是涉及一种电池模组以及电池包。
背景技术
随着技术的发展，二次电池应用范围越来越广，涉及生产或生活。二次电池也称动力电池，为可再充电电池。二次电池被广泛地使用。低容量的二次电池可用于小型电动车辆，高容量的二次电池可用于大型电动车辆，例如混合动力汽车或电动汽车。二次电池成组使用时，需要使用汇流排将每个二次电池串联或并联。通常汇流排与二次电池的正极和负极焊接连接。电池模组包括多个二次电池以及用于固定多个二次电池的连接件。
二次电池主要包括壳体、电极组件以及顶盖组件。其中，电极组件是由正极极片、负极极片和隔离膜卷绕或堆叠而成。在充放电过程中，二次电池包括的电极组件自身会发生膨胀，从而会向外部释放很大的膨胀力。
由于电池模组所包括的多个二次电池沿一方向并排设置，而电极组件释放的膨胀力沿二次电池的排列方向，因此多个二次电池所包括的电极组件释放的膨胀力叠加后会形成较大的合力，从而不仅会导致二次电池的电性能恶化，而且要求连接件具有较高的结构强度来约束抵消膨胀力，这就需要通过增大连接件的体积得以实现，进而降低了二次电池能量密度和空间利用率。
发明内容
为了解决现有技术中二次电池成组形成的电池模组自身在二次电池排列方向上的膨胀量较大，导致二次电池的电性能恶化或降低二次电池的能量密度和空间利用率的技术问题。
一方面，本申请实施例提出了一种电池模组，包括：
两个以上的二次电池，两个以上的二次电池沿第一方向并排设置，二次电池包括壳体、电极组件以及封闭部；
壳体包括具有开口的容纳孔，容纳孔沿第二方向延伸，第一方向和第二方向相交，封闭部与壳体密封连接以盖闭开口，电极组件设置于容纳孔内并且包括两个以上的电极单元，电极单元包括第一极片、第二极片和隔膜，两个以上的电极单元沿第二方向层叠设置。
根据本申请实施例的一个方面，电极单元包括宽面和窄面，宽面与封闭部相对设置，窄面位于宽面沿第一方向的一侧，宽面的面积大于窄面的面积。
根据本申请实施例的一个方面，窄面的面积与宽面的面积的比值为1/10～1/2。
根据本申请实施例的一个方面，第一极片、第二极片和隔膜卷绕形成电极单元，电极单元为扁平状结构，且包括两个宽面和两个窄面，两个窄面连接于宽面沿第一方向相对的两侧。
根据本申请实施例的一个方面，相邻两圈第一极片之间具有与窄面位置对应的第一间隙，第一间隙的尺寸为5um至50um。
根据本申请实施例的一个方面，相邻两圈第一极片之间具有与窄面位置对应的第一间隙以及与宽面位置对应的第二间隙，第一间隙的尺寸大于第二间隙的尺寸。
根据本申请实施例的一个方面，壳体的材料为金属材质，壳体包括第一侧壁、第二侧壁以及与第一侧壁和第二侧壁相连接的底壁，第一侧壁的面积大于第二侧壁、底壁的面积，相邻两个二次电池的第一侧壁相对设置，窄面与第一侧壁相对应设置。
根据本申请实施例的一个方面，窄面与第一侧壁之间具有第三间隙， 第三间隙的尺寸为0.3mm至0.9mm。
根据本申请实施例的一个方面，第一侧壁和第二侧壁的厚度均小于底壁的厚度。
根据本申请实施例的一个方面，封闭部包括顶盖板和电极端子，顶盖板和电极端子均位于电极组件沿第二方向的一侧，顶盖板连接于壳体，电极端子设置于顶盖板并且与电极组件电连接。
根据本发明实施例的一个方面，电池模组还包括第一端板和第二端板，第一端板与第二端板沿第一方向间隔设置，两个以上的二次电池设置于第一端板和第二端板之间，第一端板和第二端板的杨氏模量小于30Gpa。
根据本申请实施例的电池模组包括两个以上的沿第一方向并排设置的二次电池。各个二次电池所包括的电极单元沿壳体的容纳孔的第二方向层叠设置。在电极单元发生膨胀时，主要沿容纳孔的第二方向膨胀变形，而在第一方向上的膨胀量较小。这样，各个二次电池在第一方向上累积的膨胀合力较小。在第一方向上，电池模组不需要使用具有较高强度的结构件来约束抵消膨胀力或使用较低强度的结构件即可约束抵消膨胀力，从而有效降低电池模组的整体质量，使得电池模组自身结构更加紧凑，有效提升电池模组的能量密度。同时，电池模组自身在第一方向上膨胀量较小，能够有效提升使用过程安全性。
另一个方面，本申请实施例提供一种电池包，包括：箱体，具有容纳腔室；如上述实施例的电池模组，电池模组被容纳于容纳腔室。
根据本申请实施例的另一个方面，沿第二方向，箱体的高度大于一倍的二次电池的高度且小于两倍的二次电池的高度。
根据本申请实施例的另一个方面，电池包包括沿箱体的宽度方向排列的2个至6个电池模组，每个电池模组包括20个至32个二次电池。
根据本申请实施例的另一个方面，二次电池的厚度大于等于50mm，二次电池的高度大于等于80mm。
附图说明
下面将通过参考附图来描述本申请示例性实施例的特征、优点和技术效果。
图1是本申请一实施例的电池模组的结构示意图；
图2是本申请一实施例的二次电池的分解结构示意图；
图3是本申请一实施例的电极单元的结构示意图；
图4是本申请一实施例的二次电池的剖视结构示意图；
图5是图4中A处放大图；
图6是本申请一实施例的电池包的分解结构示意图；
图7是本申请一实施例的电池包的整体结构示意图。
在附图中，附图并未按照实际的比例绘制。
标记说明：
10、电池模组；
11、二次电池；
12、壳体；12a、容纳孔；121、第一侧壁；122、第二侧壁；123、底壁；
13、电极组件；
14、电极单元；14a、宽面；14b、窄面；141、第一极片；142、第二极片；143、隔膜；
15、顶盖组件；151、顶盖板；152、电极端子；
16、第一间隙；
17、第二间隙；
18、第三间隙；
19、第一端板；
20、第二端板；
30、电池包；
31、箱体；31a、容纳腔室；311、上盖；312、底壳；
X、第一方向；Y、第二方向。
具体实施方式
下面结合附图和实施例对本申请的实施方式作进一步详细描述。以下实施例的详细描述和附图用于示例性地说明本申请的原理，但不能用来限制本申请的范围，即本申请不限于所描述的实施例。
在本申请的描述中，需要说明的是，除非另有说明，“多个”的含义是两个或两个以上；术语“上”、“下”、“左”、“右”、“内”、“外”等指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。此外，术语“第一”、“第二”等仅用于描述目的，而不能理解为指示或暗示相对重要性。
在本申请的描述中，还需要说明的是，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；可以是直接相连，也可以通过中间媒介间接相连。对于本领域的普通技术人员而言，可视具体情况理解上述术语在本申请中的具体含义。
为了更好地理解本申请，下面结合图1至图7对本申请实施例的电池模组10进行详细描述。
参见图1所示，本申请实施例提供一种电池模组10，其包括：两个以上的本实施例的二次电池11以及用于连接两个二次电池11的汇流排。两个以上的二次电池11沿第一方向X并排设置，其中，第一方向X为两个以上的二次电池11的排列方向。汇流排的一端与两个二次电池11中的一个二次电池11连接固定，另一端与另一个二次电池11连接固定。在一个示例中，本实施例的二次电池11可以是硬壳电池或者软包电池。
参见图2所示，本申请实施例的二次电池11包括壳体12、设置于壳体12内的电极组件13以及与壳体12密封连接的封闭部。
本申请实施例的壳体12可以是四棱柱体形状或其他形状。壳体12具有容纳电极组件13和电解液的内部空间。壳体12可以由例如铝、铝合金或塑料等材料制造。
参见图3所示，本申请实施例的电极组件13包括两个以上的电极单 元14。本申请实施例的电极单元14可通过将第一极片141、第二极片142以及隔膜143一同堆叠或者卷绕而形成主体部以及与主体部相连接的极耳。隔膜143是介于第一极片141和第二极片142之间的绝缘体。本申请实施例的电极单元14由隔膜143、第一极片141以及第二极片142卷绕形成，且电极单元14为多圈的扁平状结构。在本申请实施例中，示例性地以第一极片141为正极片，第二极片142为负极片进行说明。同样地，在其他的实施例中，第一极片141还可以为负极片，而第二极片142为正极片。另外，正极活性物质被涂覆在正极片的涂覆区上，而负极活性物质被涂覆到负极片的涂覆区上。从主体部延伸出的多个未涂覆区则作为极耳，电极单元14包括两个极耳，即正极耳和负极耳，正极耳由从正极片的涂覆区延伸出的多个未涂覆区层叠形成；负极耳由从负极片的涂覆区延伸出的多个未涂覆区层叠形成。在二次电池11生产制造过程的电解液浸润工序或者后期使用过程中，本申请实施例的电极单元14所包括的活性物质层会发生膨胀，从而导致电极单元14整体发生膨胀。可选地，本申请实施例的电极单元的容量为50Ah至300Ah。
本申请实施例的封闭部可以是由铝合金、塑料以及尼龙等形成的铝塑膜，也可以是由金属等材料形成的顶盖组件15。本申请实施例的封闭部为顶盖组件15，其中，顶盖组件15包括顶盖板151和电极端子152。顶盖板151和电极端子152均位于电极组件13沿第二方向Y的一侧。二次电池11的高度方向与第二方向Y相同。壳体12的高度方向与第二方向Y相同。顶盖组件15通过顶盖板151密封连接于壳体12。电极端子152设置于顶盖板151并且与电极组件13电连接。
本申请实施例的电池模组10包括两个以上的二次电池11。两个以上的二次电池11沿第一方向X并排设置。二次电池11包括具有容纳孔12a的壳体12以及设置于容纳孔12a内的电极组件13，其中，容纳孔12a具有开口并沿着第二方向Y延伸，即第二方向Y与容纳孔12a的延伸方向平行。电极组件13包括两个以上的电极单元14。两个以上的电极单元14沿第二方向Y层叠设置，其中第二方向Y与两个以上的电极单元14的层叠方向平行。本申请实施例的第二方向Y与第一方向X相互垂直，并且第二 方向Y与容纳孔12a的开口和封闭部也相互垂直。容易理解地，本申请实施例的第二方向Y也可以与第一方向X相交并接近垂直，本申请实施例的第二方向Y也可以与容纳孔12a的开口和封闭部相交并接近垂直。本申请实施例的电极单元14发生膨胀时，电极组件13具有沿第一方向X的第一膨胀力和沿第二方向Y的第二膨胀力，由于多个电极单元14层叠，故第一膨胀力小于第二膨胀力。因此，电极组件13主要在第二方向Y上发生膨胀，从而使电极组件13的膨胀力主要沿第二方向Y，而在第一方向X上，第一膨胀力较小，故对壳体12的影响较小。本申请实施例的两个以上的二次电池11沿第一方向X并排设置时，由于每个二次电池11发生膨胀时所产生的第二膨胀力与第一方向X相交，即每个二次电池11发生膨胀时所产生的第二膨胀力的方向沿第二方向Y，因此各个二次电池11产生的第二膨胀力不会在第一方向X上累积并形成较大的合力。这样，在使用外部固定件在第一方向X上固定包括两个以上的本申请实施例的二次电池11的电池模组10时，对固定件自身的刚度和强度要求较低，从而有利减小固定件的体积或重量，进而有利于提高二次电池11和电池模组10整体的能量密度和空间利用率；再者，有利于提高二次电池的循环性能。
本申请实施例中的电极单元14包括宽面14a和窄面14b，其中，宽面14a与封闭部相对设置，这里，宽面14a与封闭部朝向宽面14a的表面相对设置并不是严格意义上的完全相对，也包括两者部分相对设置或宽面14a因膨胀而呈拱形时与封闭部朝向宽面14a的表面呈平整面时的相对设置情况。窄面14b位于宽面14a沿第一方向X的一侧，这里，宽面14a沿第一方向X具有相对的两侧，一个窄面14b连接于宽面14a的一侧。宽面14a的面积大于窄面14b的面积。由于宽面14a的面积大于窄面14b的面积，此时宽面14a相比窄面14b产生的膨胀力较大，从而进一步的减少二次电池11在第一方向X的膨胀力。优选地，窄面14b的面积与宽面14a的面积的比值为1/10～1/2，当两者的比值大于1/2时，此时窄面12b的面积较大，此时第一膨胀力的合力较大；当两者的比值小于1/10时，此时，在二次电池11相同容量的情况下，宽面14a面积过大，从而导致电解液浸润困难。
本申请实施例的电极单元14优选为由第一极片141、第二极片142和隔膜143卷绕形成。本申请实施例的电极单元14为扁平状结构。电极单元14包括相对的两个卷绕端面以及与卷绕端面相垂直的卷绕轴线。参见图3所示，电极单元14包括宽面14a和窄面14b。其中，窄面14b的至少包含部分的圆弧区域，宽面14a的数量和窄面14b的数量均为两个。两个宽面14a沿第二方向Y相对设置，并且各个宽面14a垂直于第二方向Y，而两个窄面14b沿第一方向X相对设置并且分别连接于两个宽面14a各自沿第一方向X相对的两侧。宽面14a和窄面14b围绕电极单元14的卷绕轴线交替设置。相邻两个电极单元14各自的宽面14a相互接触。本申请实施例的电极单元14发生膨胀时，宽面14a和窄面14b均会发生膨胀。宽面14a在第二方向Y上发生膨胀并且宽面14a的膨胀量大于窄面14b的膨胀量。在一个示例中，宽面14a为平整面，而窄面14b为弧形面。
参见图3所示，本申请实施例的卷绕形成的电极单元14在自身径向上形成多层第一极片141。相邻两圈第一极片141之间具有与窄面14b位置对应的第一间隙16。相邻两圈第一极片141之间具有与宽面14a位置对应的第二间隙17。这里，第一间隙16的尺寸L1以及第二间隙17的尺寸L2均指的是隔膜143与第一极片141之间的间隙以及隔膜143与第二极片142之间的间隙之和。在电极单元14的第一极片141或第二极片142上涂覆的活性物质发生膨胀时，由于膨胀力的作用，每层第一极片141会沿电极单元14的径向发生位移，而第一间隙16和第二间隙17均能够吸收每层第一极片141的位移量，因此有效减小电极单元14的窄面14b和宽面14a的膨胀位移量，从而有效减小电极单元14整体在各个方向上释放出的膨胀力。在一个实施例中，第一间隙16的尺寸L1大于第二间隙17的尺寸L2，从而第一间隙16相对于第二间隙17能够吸收更大的第一极片141膨胀位移量，使得电极单元14的窄面14b的膨胀位移量小于电极单元14的宽面14a的膨胀位移量，从而更大程度上减小膨胀力在第一方向X的累积。在一个实施例中，第一间隙16和第二间隙17由相同的两圈第一极片141之间的空隙形成。在一个实施例中，第一间隙16的尺寸L1为5um至50um。当第一间隙16的尺寸L1小于5um，电极单元14发生膨胀时，电极 单元14的窄面14b会较早地接触到壳体12，从而电极单元14在窄面14b接触到壳体12后继续膨胀时，会受到较大的反作用力，进而第一间隙16内的电解液会被挤压排出，导致锂离子无法正常传输，影响二次电池11的使用寿命。同时，由于电极单元14的窄面14b受到壳体12约束，因此使得膨胀力会向宽面14a转移，从而导致膨胀力过多地在第一方向X上累积。当第一间隙16的尺寸L1大于50um时，相邻两层第一极片141之间的第一间隙16会过大，造成锂离子传输时间过长，从而造成窄面14b动力学性能较差，易于出现析锂现象。
本申请实施例的壳体12的材料优选为金属材质。参见图2所示，壳体12包括第一侧壁121、第二侧壁122以及与第一侧壁121和第二侧壁122相连接的底壁123。顶盖组件15与底壁123沿第二方向Y相对应设置。顶盖组件15与第一侧壁121和第二侧壁122密封连接。第一侧壁121的面积大于第二侧壁122的面积，也大于底壁123的面积。相邻两个二次电池11的第一侧壁121相对设置。参见图4或图5所示，窄面14b与第一侧壁121相对应设置。在特定情况下，电极单元14的窄面14b也会发生膨胀，但其膨胀量较小，对第一侧壁121施加的压应力较小，从而各个二次电池11在第一方向X上所累积的膨胀力合力较小，再者由于第一侧壁121的面积较大，可减小第一侧壁121的变形程度。同时，电极单元14的膨胀量越大，而第一间隙16和第二间隙17的尺寸L2就会越小。电极单元14使用过程中，会消耗自身内部的电解液，因此需要不断地从外部补充电解液。在电极单元14发生膨胀时，第一侧壁121能够对窄面14b起到约束作用，使得第一间隙16会变小，从而导致壳体12内的电解液难以通过第一间隙16补充到电极单元14内部，影响电极单元14的电气性能。另外，当电极单元14发生膨胀时，位于最外层的第一极片141或第二极片142会承受较大的拉应力，从而易于导致第一极片141或第二极片142断裂。本申请实施例的第一侧壁121能够对窄面14b起到约束作用，阻止窄面14b膨胀量过大，从而有效降低第一极片141或第二极片142发生断裂的可能性。在一个示例中，第一侧壁121和第二侧壁122的数量均为两个。第一侧壁121和第二侧壁122交替设置，从而构造成横截面为矩 形的筒状结构。底壁123为矩形板状结构，与第一侧壁121和第二侧壁122密封连接。
在一个实施例中，参见图5所示，窄面14b与第一侧壁121之间具有第三间隙18。第三间隙18的尺寸L3为0.3mm至0.9mm。第三间隙18的尺寸L3小于0.3mm时，电极单元14的窄面14b发生膨胀的程度较小时就会完全侵占第三间隙18并与第一侧壁121接触并对第一侧壁121施加压应力，从而在电极单元14的窄面14b达到最大膨胀量时，电极单元14对第一侧壁121施加的应力会过大，进而能够导致第一侧壁121发生变形或者导致整个电池模组10在第一方向X上发生变形。第三间隙18的尺寸L3大于0.9mm时，电极单元14的窄面14b发生膨胀的程度较大时才能够完全侵占第三间隙18并与第一侧壁121接触，从而导致第一侧壁121无法对电极单元14形成有效约束，进而出现因电极单元14的窄面14b膨胀量过大而导致电极单元14最外层的第一极片141或第二极片142发生断裂的情况。
在一个实施例中，第一侧壁121和第二侧壁122的厚度均小于底壁123的厚度M。由于本申请实施例的电极单元14主要的膨胀方向是沿第二方向Y，因此电极单元14发生膨胀时，相对于第一侧壁121和第二侧壁122，电极单元14对底壁123施加的应力更大。增加底壁123的厚度M能够增强底壁123的强度，提高对电极单元14的约束性能以及自身抗变形性能。在电极单元14的宽面14a朝向底壁123的实施例中，底壁123对电极单元14的膨胀量起到约束作用，使得电极单元14的膨胀量不会过大，从而第一间隙16不会被完全挤压侵占而消失，保证第一间隙16中的电解液充足。另外，减小第一侧壁121和第二侧壁122的厚度，有利于降低二次电池11整体的重量，从而有利于提高二次电池11和电池模组10的能量密度。
参见图1所示，本申请实施例的电池模组10还包括第一端板19和第二端板20。第一端板19与第二端板20沿第一方向X间隔设置。两个以上的二次电池11设置于第一端板19和第二端板20之间。第一端板19和第二端板20的杨氏模量均小于30Gpa。由于本申请实施例电池模组10所包 括的各个二次电池11在第一方向X上的膨胀力较小，因此第一端板19和第二端板20在第一方向X上的厚度可以设计的更小，自身的刚度和强度要求也较低，从而有利于减轻第一端板19和第二端板20的重量，有利于提升二次电池11和电池模组10的能量密度，同时也降低对第一端板19和第二端板20的材质的限定，选材更加广泛，降低加工制造难度和成本。在一个实施例中，电池模组10还包括与第一端板19和第二端板20同时连接的连接件。连接件能够拉紧第一端板19和第二端板20，从而拉紧各个二次电池11，提升各个二次电池11的位置稳定性。
本申请实施例的电池模组10包括两个以上的沿第一方向X并排设置的二次电池11。各个二次电池11所包括的电极单元14沿第二方向Y层叠设置。本申请实施例的电极单元14发生膨胀时，主要沿第二方向Y膨胀变形，而在第一方向X上的膨胀量较小。这样，各个二次电池11在第一方向X上累积的膨胀合力较小。在第一方向X上，电池模组10不需要使用具有较高强度的结构件来约束抵消膨胀力或使用较低强度的结构件即可约束抵消膨胀力，从而有效降低电池模组10的整体质量，使得电池模组10自身结构更加紧凑，有效提升电池模组10的能量密度。同时，电池模组10自身在第一方向X上膨胀量较小，能够有效提升使用过程安全性。
参见图6和图7所示，本申请实施例还提供一种电池包30。该电池包30可以应用于汽车等车辆。汽车具有容纳电池包30的容纳箱体，而容纳箱体一般会位于汽车的底部，且汽车的底盘与地面距离较近，而容纳箱体的高度决定了汽车的高度空间，因此，为了减小汽车的高度空间，这就要求容纳箱体在汽车的长度方向或者宽度方向上加长，而电池包30和电池模组10的长度就会相应地加长，此时，在长度方向上的膨胀力相应增大，这就需要电池包30既能减少汽车高度方向上的占用空间，又能使长度方向的膨胀力不至于过大。汽车的高度方向与第二方向Y平行，汽车长度方向或者宽度方向中的一个与第一方向X相同。
本申请实施例的电池包30包括箱体31以及设置于箱体31内的上述实施例的电池模组10。电池模组10的数量可以是一个，也可以是两个以上。
本申请实施例的箱体31具有用于容纳电池模组10的容纳腔室31a。在一个实施例中，箱体31包括上盖311和底壳312。上盖311和底壳312能够密封连接以将电池模组10密封于容纳腔室31a内。被容纳于容纳腔室31a的电池模组10能够与底壳312连接固定。
在一个实施例中，箱体31的高度N大于一倍的二次电池11的高度H且小于两倍的二次电池11的高度H，其中，箱体31的高度方向与第二方向Y相同。这样，箱体31和电池模组10的各个二次电池11之间预留有间隙。电极单元14发生过度膨胀并对顶盖组件15施加过大应力时，该间隙能够对顶盖组件15形成让位，使得顶盖组件15能够与壳体12脱离连接，从而降低二次电池11过度膨胀无法泄压而发生爆炸的可能性。
在一个实施例中，电池包30包括沿箱体31的宽度方向排列的2个至6个电池模组10。每个电池模组10包括20个至32个二次电池11。本申请实施例中，箱体31的宽度方向与第一方向X和第二方向Y相垂直，而箱体31的长度方向与第一方向X相同。由于本申请实施例的二次电池11在第一方向X上的膨胀量较小，因此在第一方向X上能够并排设置更多的二次电池11，从而极大地提升电池模组10的能量密度。
在一个实施例中，二次电池11的厚度D(参见图1所示)大于等于50mm。二次电池11的高度H(参见图4所示)大于等于80mm。二次电池11的厚度方向与第一方向X相同。二次电池11的高度方向与第二方向Y相同。
本申请实施例的电池包30括包括箱体31和电池模组10。电池模组10发生膨胀时，电池模组10在箱体31的长度方向上的膨胀量较小，从而电池模组10在长度方向上释放的膨胀力较小，对箱体31施加的应力较小。这样，在第一方向X上，不需要使用结构强度较高的结构件来约束电池模组10，有利于减小结构件的体积和重量，从而有利于电池包30设计轻量化，提高电池包30的能量密度。同时也不需要箱体31在第一方向X上具有较强的刚度和强度，降低箱体31的结构要求。
虽然已经参考优选实施例对本申请进行了描述，但在不脱离本申请的范围的情况下，可以对其进行各种改进并且可以用等效物替换其中的部 件。尤其是，只要不存在结构冲突，各个实施例中所提到的各项技术特征均可以任意方式组合起来。本申请并不局限于文中公开的特定实施例，而是包括落入权利要求的范围内的所有技术方案。

Claims (15)

  1. 一种电池模组，其中，包括：
    两个以上的二次电池，两个以上的所述二次电池沿第一方向并排设置，所述二次电池包括壳体、电极组件以及封闭部；
    所述壳体包括具有开口的容纳孔，所述容纳孔沿第二方向延伸，所述第一方向和所述第二方向相交，所述封闭部与所述壳体密封连接以盖闭所述开口，所述电极组件设置于所述容纳孔内并且包括两个以上的电极单元，所述电极单元包括第一极片、第二极片和隔膜，两个以上的所述电极单元沿所述第二方向层叠设置。
  2. 根据权利要求1所述的电池模组，其中，所述电极单元包括宽面和窄面，所述宽面与所述封闭部相对设置，所述窄面位于所述宽面沿所述第一方向的一侧，所述宽面的面积大于所述窄面的面积。
  3. 根据权利要求2所述的电池模组，其中，所述窄面的面积与所述宽面的面积的比值为1/10～1/2。
  4. 根据权利要求2所述的电池模组，其中，所述第一极片、所述第二极片和所述隔膜卷绕形成所述电极单元，所述电极单元为扁平状结构，且包括两个所述宽面和两个所述窄面，两个所述窄面连接于所述宽面沿所述第一方向相对的两侧。
  5. 根据权利要求4所述的电池模组，其中，相邻两圈所述第一极片之间具有与所述窄面位置对应的第一间隙，所述第一间隙的尺寸为5um至50um。
  6. 根据权利要求4所述的电池模组，其中，相邻两圈所述第一极片之间具有与所述窄面位置对应的第一间隙以及与所述宽面位置对应的第二间隙，所述第一间隙的尺寸大于所述第二间隙的尺寸。
  7. 根据权利要求4所述的电池模组，其中，所述壳体的材料为金属材质，所述壳体包括第一侧壁、第二侧壁以及与所述第一侧壁和所述第二侧壁相连接的底壁，所述第一侧壁的面积大于所述第二侧壁、所述底壁的面积，相邻两个所述二次电池的所述第一侧壁相对设置，所述窄面与所述第 一侧壁相对应设置。
  8. 根据权利要求7所述的电池模组，其中，所述窄面与所述第一侧壁之间具有第三间隙，所述第三间隙的尺寸为0.3mm至0.9mm。
  9. 根据权利要求7所述的电池模组，其中，所述第一侧壁和所述第二侧壁的厚度均小于所述底壁的厚度。
  10. 根据权利要求1所述的电池模组，其中，所述封闭部包括顶盖板和电极端子，所述顶盖板和所述电极端子均位于所述电极组件沿所述第二方向的一侧，所述顶盖板连接于所述壳体，所述电极端子设置于所述顶盖板并且与所述电极组件电连接。
  11. 根据权利要求1至10任一项所述的电池模组，所述电池模组还包括第一端板和第二端板，所述第一端板与所述第二端板沿所述第一方向间隔设置，两个以上的所述二次电池设置于所述第一端板和所述第二端板之间，所述第一端板和所述第二端板的杨氏模量小于30Gpa。
  12. 一种电池包，其中，包括：
    箱体，具有容纳腔室；如权利要求1至11任一项所述的电池模组，所述电池模组被容纳于所述容纳腔室。
  13. 根据权利要求12所述的电池包，其中，沿所述第二方向，所述箱体的高度大于一倍的所述二次电池的高度且小于两倍的所述二次电池的高度。
  14. 根据权利要求12所述的电池包，其中，所述电池包包括沿所述箱体的宽度方向排列的2个至6个所述电池模组，每个所述电池模组包括20个至32个所述二次电池。
  15. 根据权利要求13或14所述的电池包，其中，所述二次电池的厚度大于等于50mm，所述二次电池的高度大于等于80mm。
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