Potting device and potting method for battery module and battery module

Abstract

The present invention provides a potting device for a battery module, which is capable of simultaneous multi-station pouring, ensures that the potting material is completely poured before foaming begins, greatly improves the potting efficiency, and is applicable to various battery module designs, has low cost for component replacement, is easy to clean, and resulting in the potting material having a consistent height and a good homogeneity, and free of defects such as bubbles and blisters. The present invention also provides a method for potting a battery module and a battery module obtained therefrom, which is particularly suitable for electric vehicles as their power source.

Description

[0001] POTTING DEVICE AND POTTING METHOD FOR BATTERY MODULE AND BATTERY MODULE

[0002] The present invention relates to a potting device for battery module, a potting method thereof and a battery module obtained therefrom.

[0003] Polyurethane materials are widely used in such fields as automotive interior, building insulation, central air conditioning, thermal insulation box, and chemical tank due to their properties such as outstanding energy absorption, excellent high strength and adhesion, excellent thermal insulation, excellent environmental compatibility, excellent durability, high flame retardancy, moisture resistance, and high temperature resistance. In particular, its property combination of thermal insulation, flame retardancy and high adhesive strength to substrates has attracted extensive attention and research interest from battery cell bonding manufacturers and electric vehicle manufacturers.

[0004] Electric vehicle batteries have gone through a process of research and development from battery module design, cell-to-pack (CTP) to cell-to-chassis (CTC). In this process of research and development, the combination of the development of polyurethane system performance and the efficient processing of polyurethane resin system is becoming more and more important for the research and development of cell-to-pack (CTP) and cell-to-chassis (CTC).

[0005] With the development of electric vehicles and these technologies, the number of cells in a single battery module is increasing, and the layout is more compact, which requires a rigidity and strength of the entire battery pack consistent with that in the cell-to-chassis (CTC), whereby higher challenges are posed to the cell potting process.

[0006] In the traditional cell potting method, single or multiple pouring gun heads are used to fill the gaps between cells one by one, which results in low potting efficiency. It is often the case that it has not yet been poured at subsequent pouring points, while the previous potting material has begun with foaming, resulting in phenomena such as uneven foam, hollowing, and creases. Single or multiple spray guns may also be used for mobile pouring, which is also very prone to uneven foam and hollowing.

[0007] W02022 / 188050 discloses a method for potting a battery comprising injecting a reaction mixture into the gaps around the battery so that the reaction mixture reacts, swells and cures. However, this method does not relate to a method for improving the potting efficiency while ensuring the potting material having a consistent height and without voids or bubbles in the foam.

[0008] WO2019 / 161292 discloses a method for potting a battery cell comprising applying a potting composition as a liquid such that the potting composition flows through gaps between adjacent cells and between the cells and the walls of the battery casing. The liquid potting composition is sufficiently flowable to be kept at substantially equal heights before curing to form a potting compound, which hardens to a solid and forms a potting compound after application. Said potting composition comprises at least 15% by weight of a liquid flame retardant. In this method, it relies on the flowability of the potting composition to achieve uniform distribution of the potting compound, which, however, is not applicable to other potting composition formulae.

[0009] The known battery potting methods are mainly applied to battery modules with fully encapsulated potting materials, but they cannot meet the requirements of electric vehicle manufacturers that the surface of the battery cells should not be in contact with the potting materials. Additionally, it is difficult to achieve the requirement of a smooth surface, defect-free, and uniform foam density of the cured potting material.

[0010] Therefore, there is an urgent need to develop a battery cell potting method suitable for industrial large-scale production.

[0011] In one aspect, the present invention provides a potting device for battery module comprising: a mixing and discharging device for the potting material (110), which is connected to at least a shunt pouring device (100); wherein the mixing and discharging device for the potting material (110) has an outlet with an outlet inner cross-sectional area Sout, wherein the shunt pouring device comprises at least one main pipe (115) and at least two branch pipes comprising at least one of rigid pipe fitting (120) and bendable flexible pipe (160), each of the branch pipes has an outlet with an outlet inner cross-sectional area and the outlet inner cross- sectional areas Stanch of the branch pipes are identical or different, wherein the main pipe (115) is connected to each of the branch pipes, and the shunt pouring device is connected to the outlet of the mixing and discharging device for the potting material (110) via the main pipe (115), wherein the following applies to the sum of the outlet inner cross-sectional areas of all branch pipes and wherein the mixing and discharging device for the potting material (110) is a discharging device with an output flow rate of greater than or equal to 100 g / s.

[0012] Preferably, the potting device for a battery module further comprises a cover plate which is made of a material comprising at least a foam board, preferable a silicone foam board, a polyethylene foam board, a polystyrene foam board, a polyurethane foam board or combinations thereof, covering and contacting the upper surface of the cells, more preferably covering and contacting all the upper surfaces of the cells. The cover plate most preferably comprises at least one through-hole for allowing the potting material and / or the outlet of the branch pipes to pass through the through-holes.

[0013] In another aspect, the present invention provides a method for potting a battery module, wherein

[0014] (i) a casing and a number of cells arranged in the casing with gaps and spaces between them is provided,

[0015] (ii) a potting material is poured into a part of the gaps between the cells and / or a part of the spaces between the cells and the casing of the battery module by using a potting device for a battery module of the present invention,

[0016] (iii) the poured potting material flows to all the residual gaps and spaces, and

[0017] (iv) the potting material is foamed and cured, wherein preferably, the number of gaps and spaces where the potting material is poured into is equal to the number of the outlets of the branch pipes of the potting device for a battery module.

[0018] In a preferred embodiment of the present invention, the method for potting a battery module comprises the steps

[0019] (i) a casing and a number of cells arranged in the casing with gaps and spaces between them is provided,

[0020] (ii) the cells are covered on their upper surfaces with at least one cover plate having at least one through-hole located above a gap or space to be filled, and the lower surface of the cover plate is the surface which is in contact with the cells, and (iii) a potting material is poured through the through-holes into a part of the gaps between the cells and / or into a part of the spaces between the cells and the casing of the battery module by using a potting device for a battery module of the present invention, and

[0021] (iv) the poured potting material flows to all the residual gaps and spaces,

[0022] (v) the potting material is foamed and cured, wherein preferably, the number of gaps and spaces where the potting material is poured into is equal to the number of through-holes, and / or is equal to the number of the outlets of the branch pipes of the potting device for battery module, and / or preferably, before the curing is completed, the cover plate is kept from displacing in its vertical direction z.

[0023] In another aspect, the present invention also provides a battery module comprising a casing and a number of cells arranged in the casing, wherein a cured potting material obtained by the method for potting a battery module of the present invention is present between the cells and between the cells and the casing.

[0024] In another aspect, the present invention also provides an electric vehicle comprising the at least one of the battery modules.

[0025] Description of drawings

[0026] Fig. 1 is a schematic view of a preferred potting device for battery module of the present invention. Fig. 2 is a cross-sectional view of a shunt pouring device 200 of the present invention, wherein the branch pipe is of semi-n type.

[0027] Fig. 3 is a cross-sectional view of a shunt pouring device of the present invention of three-way pipe type.

[0028] Fig. 4 is a schematic view of a shunt pouring device of the present invention of four-way pipe type, and Fig. 4b is a top view of Fig. 4a.

[0029] Fig. 5 is a schematic view of a shunt pouring device of the present invention of five-way pipe type, and Fig. 5b is a top view of Fig. 5a.

[0030] Fig. 6 is a schematic view of a shunt pouring device of the present invention of five-way pipe type.

[0031] Fig. 7 is a schematic view of a shunt pouring device of the present invention of nine-way pipe type. Fig. 8a and 8b are schematic views of a shunt pouring device of the present invention of seven-way pipe type.

[0032] Fig. 9 is a schematic view of a battery module of the present invention.

[0033] Fig. 10 is a partial schematic view of the cells and the pouring ports in a battery module of the present invention.

[0034] Fig. 11 is a partial schematic view of the cells and the pouring ports in a battery module of the present invention.

[0035] Fig.12 is a photograph of the battery module obtained after potting in Example 9.

[0036] Fig.13 is a photograph of the battery module obtained after potting in Comparative Example 1. Fig.14 is a photograph of the battery module obtained after potting in Comparative Example 2.

[0037] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. In case of conflict, the definition provided herein shall prevail.

[0038] Unless stated otherwise, all percentages, parts, proportions, etc. are by weight. Those skilled in the art should understand that the sum of all components in the composition may be appropriately 100%. When quantity, concentration or other values or parameters are given as ranges, preferred ranges or preferred upper and lower limit values or specific values, it should be understood that all ranges formed by the paired values of any upper limit range or preferred value and any lower limit range or preferred value are specifically disclosed, regardless of whether the ranges are separately disclosed. Unless stated otherwise, when a numerical range is referenced herein, the range includes its endpoints, and all integers and fractions within the range.

[0039] When the term "about" or "approximately" is used with a numerical variable, it generally means that the value of the variable and all values of the variable are within the experimental error (for example, within the 95% confidence interval of the mean value) or within ± 10% of the specified value, or within a wider range.

[0040] The term "optional" or "optionally" as used herein refers to the event or situation described later that may or may not occur, which includes the occurrence and non-occurrence of the event or situation, as well as the optional situation of the content described later. For example, when the content of a component herein is of 0% to 5%, it means that the component may be optionally present, that is, both the case of absence (0%) and presence (>0-5%) are covered. The terms "including", "comprising", "having", "containing" or "involving" and other variations thereof herein are inclusive or open, and do not exclude other elements or process steps not listed. Those skilled in the art should understand that the above terms such as "including" cover the meaning of "consisting of... The expression "consisting of... " excludes any unspecified elements, steps or ingredients. The expression "substantially consisting of..." means that the scope is limited to the specified elements, steps or components, as well as optional elements, steps or components that will not materially affect the basic and new features of the subject matters to be protected. It should be understood that the expression "comprising" covers the expressions "substantially consisting of..." and "consisting of... ". The term "selected from..." refers to one or more elements in the group listed below, which are selected independently, and may include a combination of two or more elements.

[0041] The term "one or more" or "at least one" as used herein refers to one, two, three, four, five, six, seven, eight, nine or more.

[0042] The terms "and / or" used herein include "and" and "or". A plurality of elements, parts or steps defined by "and / or" represent any one of the elements, parts or steps and any combination thereof. For example, "A and / or B" covers A, B and A+B; "A, B and / or C" covers A, B, C, A+B, A+C, B+C and A+B+C.

[0043] Unless stated otherwise, the terms "combination thereof', "any combination thereof' and "mixture thereof' refer to multi-component mixtures of said elements, such as mixtures of two, three, four and up to the maximum possible number of components.

[0044] In addition, if no number is indicated in front of the parts or components of the present invention, it means that there is no limit on the number of the occurring (or existing) parts or components. Therefore, it should be interpreted as including one or at least one, and the singular form of the part or component also includes the plural, unless the number clearly indicates the singular.

[0045] Herein, "more" or "several" means two or more than two. There are no specific requirements for which of them, unless specified otherwise. Unless explicitly stated in the context, "a" may cover the singular and plural forms.

[0046] Herein, a "cell" refers to a single electrochemical cell containing both positive and negative electrodes, also called “battery cell”. A "battery module" comprises a number of cells that are encapsulated together in the same casing. The cell and the battery module in the present invention are mainly used in electric vehicles. The number of the cells in the battery module may be 10-1000, preferably 100-900.

[0047] Herein, "cross-section" refers to a cross-section perpendicular to the length direction of the main pipe or the branch pipes. Since the main pipe and the branch pipes in the present invention are hollow pipes, they have an inner cross-section and an outer cross-section. Herein, unless otherwise stated, the cross-section refers to the inner cross-section. Correspondingly, unless otherwise stated, the cross-sectional area refers to the inner cross-sectional area.

[0048] Herein, the “outlet inner cross-sectional area” refers to “the inner cross-sectional area of the outlet”, and the “outlet outer cross-section” refers to the outer cross-section of the outlet. If the cross-section of the outlet varies over the length of the outlet, the terms “cross-sectional area” and “cross-section” refer to the cross-section at the end of the outlet in flow-direction.

[0049] Herein, "dimensions" include length, width, height, area and volume. Dimensions of the crosssection include width, length, diameter, side length and area etc. When the cross-section is circular or quasi-circular, the dimensions include diameter, maximum diameter and area. When the crosssection is square, the dimensions include length, width and area. When the cross-section is triangular, the dimensions include side length and area. When the cross-section is polygonal or irregular, the above-mentioned dimensions include the maximum width and area.

[0050] In the present invention, the main pipe or the branch pipes may be constituted in the form of a pipe fitting or a pipe, or in the form of a channel, provided that the potting material can flow and be transported therein. For example, a part of the structure may be removed from a solid body to form a channel that functions as a pipe, although it is not in the shape of a pipe in appearance.

[0051] In the present invention, the flow rate refers to the weight of the potting material passing through the outlet inner cross-section of the mixing and discharging device for the potting material in one second, expressed in g / s.

[0052] The present invention provides a potting device for battery module comprising: a mixing and discharging device for the potting material (110) and at least a shunt pouring device (100); wherein the mixing and discharging device for the potting material (110) has an outlet with an outlet inner cross-sectional area Sout, wherein the shunt pouring device comprises at least one main pipe (115) and at least two branch pipes comprising at least one of rigid pipe fitting (120) and bendable flexible pipe (160), each of the branch pipes has an outlet with an outlet inner cross-sectional area Si,„llfb. and the outlet inner cross- sectional areas of the branch pipes are identical or different, wherein the main pipe (115) is connected to each of the branch pipes, and the shunt pouring device is connected to the outlet of the mixing and discharging device for the potting material (110) via the main pipe (115), wherein the following applies to the sum of the outlet inner cross-sectional areas of all branch pipes and wherein the mixing and discharging device for the potting material (110) is a discharging device with an output flow rate of greater than or equal to 100 g / s.

[0053] In the present invention, the following applies to the sum of the inner cross-sectional areas of the outlets of all branch pipes: more preferably

[0054] By controlling the outlet inner cross-sectional area of all branch pipes, the size of the foam cells in the cured potting material can be uniform without problems of local discoloration and blackening, so that the strength of the foam stays the same.

[0055] In one preferred embodiment of the present invention, the potting device for a battery module further comprises a cover plate which is made of a material comprising at least a foam board, preferable a silicone foam board, a polyethylene foam board, a polystyrene foam board, a polyurethane foam board or combinations thereof, covering and contacting the upper surface of the cells (typically the upper surface is the surface where the positive electrode of the cells are located), preferably covering and contacting all the upper surfaces of the cells. After curing, the cover plate can be removed. The cover plate can help guide the flow of the potting material, while protecting the cells and achieving a defect-free cured potting material with a smooth surface.

[0056] In the present invention, the aforementioned polyurethane foam board preferably has a film layer arranged on the surface in contact with the cells, the film is preferably one or more of polyhexafluoropropylene, polytetrafluoroethylene, polytrifluoroethylene, polytrifluorochloroethylene, polyvinylidene difluoride, polyvinyl fluoride, polyethylene, polypropylene, any mixture thereof and any copolymer thereof, more preferably polyhexafluoropropylene, polytetrafluoroethylene, polytrifluoroethylene, polytrifluorochloroethylene, polyvinylidene difluoride, polyvinyl fluoride, any mixture thereof and any copolymer thereof.

[0057] In the present invention, the cover plate has a thickness greater than or equal to 3mm, preferably 3mm-10cm, and more preferably lcm-5cm. By selecting the thickness of the cover plate and the material, a cured potting material with a smooth surface, free of defects, and uniform in density can be obtained.

[0058] In this invention, the cover plate can also be made of at least a foam board in combination with a rigid material, wherein the part in contact with the upper surfaces of the cells is the foam board. The rigid material can be selected from one or more of metal, alloy and plastic.

[0059] In a more preferred embodiment of the present invention, the cover plate has at least one through- hole for allowing the potting material and / or the outlet of the branch pipes to pass through. The number of through-holes is preferably equal to the number of outlets of the branch pipes.

[0060] In the present invention, the number of the branch pipes is not particularly limited, and can be changed and adjusted according to the design structure of the battery module. The number of the branch pipes may be 2-100, preferably 2-50, more preferably 2-30. In the present invention, the number of branch pipes is preferably equal to or matched with the number of the pouring ports, more preferably the number of the pouring ports is equal to the number of the branch pipes, or multiple of, preferably 2-4 times of the number of the branch pipes.

[0061] In the present invention, the number of through-holes is preferably 2-100, more preferably is 2-50, most preferably is 2-30.

[0062] In the present invention, the dimension of the outlet outer cross-section of the branch pipes is not particularly required, and is preferably set so that the potting material can be poured via the outlets of the branch pipes into the gaps formed between the cells.

[0063] In the present invention, the dimension of the outlet outer cross-section of the branch pipes is preferably set so that the outlets of the branch pipes can be inserted into the gaps formed between the cells for pouring the potting material. For example, the maximum width of the outlet outer cross- section of the branch pipes is less than the spacing between cells. When the outer cross-section of the branch pipes is circular, the maximum width is its diameter. In this case, the contamination of the upper surface of the cells by the potting material can be avoided to the greatest extent, while the potting efficiency is ensured, so as to avoid the case that the potting material begins with foaming or curing before it is completely poured.

[0064] It is understood that the dimension of the outlet outer cross-section of the branch pipes in the present invention may also be set to be greater than the spacing between the cells. In this case, the outlet of the branch pipes does not need to be inserted into the gaps formed between the cells, but it is poured from above the cells. Such dimension of the outlet outer cross-section of the branch pipes can be used for the battery module that requires the upper surface of the cells to be covered with the potting material.

[0065] In the present invention, at least a part of at least one of the branch pipes is a bendable flexible pipe. Preferably, the part of at least one of the branch pipes comprising the outlet (outlet part) is a bendable flexible pipe. The bendable flexible pipe in the present invention is a pipe that can be deformed under external force at room temperature. The material of the bendable flexible pipe is not particularly limited, provided that it is not obviously detrimental to the polyurethane potting material. The material that may be selected includes metals, rubbers and plastics, preferably plastics, such as polyesters, polycarbonates, polyurethanes, polyamides, polyolefins, polychloroolefins, and the like. The bendable flexible pipe is preferably a transparent or translucent flexible pipe, which facilitates the observation of the flow or blockage of the potting material in the pipe. The use of bendable flexible pipes can adapt to the design requirements of various battery module, facilitate replacement, and reduce the risk of damage to the cells caused by the collision between the branch pipe and the cells at the same time.

[0066] In the present invention, at least a part of all branch pipes is preferably a bendable flexible pipe. More preferably, the part comprising the outlet (outlet part) of all branch pipes is a bendable flexible pipe.

[0067] In the present invention, at least a part of the branch pipes is a rigid pipe fitting. The material of the rigid pipe fitting is not particularly limited, including but not limited to metals and plastics, preferably thermosetting or thermoplastic plastics. Thermosetting plastics may include epoxy resins and / or polyurethane resins. Thermoplastic plastics may include polyesters, polycarbonates, polyurethanes, polyamides, polyolefins, polychloroolefins, liquid crystal polymers, acrylonitrile-butadiene-styrene plastics (ABS), polyether ether ketones, polysulfones, polyethersulfones and / or polyphenylene sulfides, etc. In a preferred embodiment of the present invention, the branch pipes include a rigid pipe fitting and a bendable flexible pipe, wherein the rigid pipe fitting is connected to the main pipe.

[0068] In a preferred embodiment of the present invention, the branch pipes include a rigid pipe fitting and a bendable flexible pipe, wherein the bendable flexible pipe is connected to the main pipe.

[0069] In a preferred embodiment of the present invention, the rigid pipe fitting has the same cross-sectional shape as that of the bendable flexible pipe.

[0070] In the present invention, the outlet inner cross-sectional areas of the branch pipes may be identical or different. The outlet outer cross-sectional areas of the branch pipes may be identical or different.

[0071] In the present invention, the cross-sectional shape of the branch pipes is not particularly limited, including but not limited to circular, elliptical, quasi-circular, triangular, pentagonal and hexagonal, etc., preferably circular, quasi-circular and triangular.

[0072] In the present invention, the cross-sectional shape of the bendable flexible pipe or of the rigid pipe fitting of the branch pipes is not particularly limited, including but not limited to circular, elliptical, quasi-circular, triangular, pentagonal, hexagonal, etc., preferably circular, quasi-circular and triangular.

[0073] In a preferred embodiment of the present invention, the dimensions of the branch pipes, for example, the inner diameter thereof, may vary in its length direction, or may have the same dimension. The change of dimensions, such as the change of the inner diameter, may be a continuous gradual change, or a stepped change. Preferably, the inlet and outlet of the branch pipes, for example, the inner diameter have the same size, or the inlet size of the branch pipes is greater than or equal to the outlet size, for example, the inner diameter of the inlet is greater than or equal to that of the outlet.

[0074] In the present invention, the length difference among the branch pipes is preferably less than or equal to 30%, preferably less than or equal to 20%, based on the length of the shortest one among all branch pipes. The length difference refers to the difference in length between any one and the shortest one among all branch pipes. The branch pipe length is understood to be the path length from the inlet to outlet of the branch pipes. In the present invention, the main pipe is mainly used to connect the branch pipes to the outlet of the mixing and discharging device for the potting material. The length of the main pipe is not particularly limited, as long as it can function as a connection, which may be a pipe with a certain length, or a fastener, for example a nut, may also be used as the main pipe. In some cases that the outlet of the mixing and discharging device for the potting material can be connected with each of the branch pipes in an integrated manner, the outlet of the mixing and discharging device for the potting material functions as the main pipe at the same time, which is also within the scope of the present invention. Other structures having the same function as the main pipe should also be included in the scope of the present invention.

[0075] In a preferred embodiment of the present invention, the main pipe is a pipe fitting. The inner diameter of the main pipe may vary in its length direction, or the main pipes may have the same inner diameter. The change of the inner diameter may be a continuous gradual change, or a stepped change. Preferably, the inlet and outlet of the main pipe have the same inner diameter, or the inner diameter of the inlet of the main pipe is greater than or equal to that of the outlet.

[0076] In the present invention, the main pipe may be a rigid pipe fitting or a flexible pipe fitting, or a combination of both, preferably a rigid pipe fitting. The material of the rigid pipe fitting is not particularly limited, including but not limited to metals and plastics, preferably thermosetting or thermoplastic plastics. Thermosetting plastics may include epoxy resins and / or polyurethane resins. Thermoplastic plastics may include polyesters, polycarbonates, polyurethanes, polyamides, polyolefins, polychloroolefins, liquid crystal polymers, acrylonitrile-butadiene-styrene plastics (ABS), polyether ether ketones, polysulfones, polyethersulfones and / or polyphenylene sulfides, etc.

[0077] In a preferred embodiment of the present invention, the dimensions of the main pipe may vary in its length direction, or may have the same dimension. The dimension change may be a continuous gradual change, or a step change. Preferably, the dimension of the inlet of the main pipe is greater than or equal to that of the outlet thereof.

[0078] In a preferred embodiment of the present invention, the combination of rigid pipe fittings of the main pipe and the branch pipes may be replaced by a multi-way pipe, including but not limited to a three- way pipe, a four-way pipe, a five- or more-way pipe or a combination thereof. In the multi-way pipe, the main pipe is the inflow pipe, and the branch pipe is the outflow pipe. In the present invention, the main pipe of the shunt pouring device may also be of a straight tubular structure, if the outlet of the mixing and discharging device for the potting material is of a straight tubular structure, so that it is conveniently connected with the outlet pipe.

[0079] In a preferred embodiment of the present invention, the number of branch pipes is an even number of 2 or more, such as 2, 4, 6, 8, 10, 12, 14, etc., preferably 4, 6, 8 or 10. In this case, the branch pipes are preferably distributed in an axisymmetric manner around the main pipe, wherein the central line of the main pipe is taken as the axis.

[0080] In a preferred embodiment of the present invention, the number of branch pipes is an odd number of 3 or more, such as 3, 5, 7, 9, 11, 13, 15, etc., preferably 3, 5 or 7. In this case, the branch pipes are preferably evenly distributed radially with the central line of the main pipe as the axis.

[0081] In the present invention, the shape of the branch pipes, especially of rigid pipe fittings of the branch pipes may be selected as desired, including but not limited to a straight tubular structure, a bended tubular structure, and a semi-n-shaped structure. The bended tubular structure may be a right-angled bended tubular structure.

[0082] In the present invention, the main pipe and / or at least one of the branch pipes is provided with at least one intake pipe for introducing high-pressure gas into the shunt pouring device, in order to clean the residual potting material or foam formed by the potting material in the shunt pouring device. Preferably, the intake pipe may also be provided with at least one valve for controlling the high- pressure gas. The pressure of the high-pressure gas in the intake pipe may be of 2-20 bar, preferably 8-15 bar, and the flow rate of the gas may be of 5-50 Nm3 / h, preferably 30-50 Nm3 / h.

[0083] In the present invention, the connection between the main pipe and the mixing and discharging device for the potting material may be a fixed connection or a detachable connection, preferably a detachable connection. This allows for convenient replacement of the shunt pouring device to prevent the occurrence of the case such as the blockage of the pipe opening by the potting material, which may result in pouring failure. It is also possible to replace it with a shunt pouring device more suitable for pouring requirements according to different battery module designs. The detachable connection includes a variety of conventional connections in the art, such as threaded connection, flanged connection, socketed connection, clamped connection or self-locking connection, preferably selflocking connection. In the present invention, the connection between the main pipe and the branch pipes or the connection between the main pipe and the rigid pipe fittings of the branch pipes may be a fixed connection or a detachable connection, preferably a detachable connection. The detachable connection includes a variety of conventional connections in the art, such as threaded connection, flanged connection, socketed connection, clamped connection or self-locking connection, preferably self-locking connection.

[0084] In a preferred embodiment, the branch pipes consist of a rigid pipe fitting (120), a bendable flexible pipe (160) and a connection between them.

[0085] In the present invention, the connection between the rigid pipe fitting and the bendable flexible pipe of the branch pipes is preferably a detachable connection. The detachable connection includes a variety of conventional connections in the art, such as threaded connection, flanged connection, socketed connection, clamped connection or self-locking connection, preferably self-locking connection.

[0086] In the present invention, the threaded connection refers to a detachable connection, in which the connected parts are integrated by a threaded fitting (or the threaded parts of the connected pieces). Common threaded fittings include bolts, studs, screws and set screws.

[0087] The socketed connection of the present invention refers to a connection, in which the spigot at one end of the pipe fitting is inserted into the socket of the piece to be connected, and the ring gap is sealed with a filling material (such as hemp or asbestos rope).

[0088] The clamped connection of the present invention refers to a connection, in which a sealing ring is sandwiched between the clamp joints at both ends, and a buckle is arranged for locking and fixing.

[0089] In the present invention, the self-locking connection refers to a connection that can achieve the locking of two connected pieces without additional fasteners, adhesives or components. Examples thereof include but are not limited to two-way quick self-locking joints, three-way quick self-locking joints, self-locking quick joints of single expansion buckle type, self-locking quick joints of double expansion buckle type, metal push-pull self-locking connections, etc. Due to the fast and easy installation and disassembly of the self-locking connection, it is preferred to use self-locking connection for the detachable connection. In the present invention, the main pipe and the outlet of the mixing and discharging device for the potting material, the main pipe and the branch pipes, or the outlet of the mixing and discharging device for the potting material, the main pipe and the branch pipes may also be integrally formed, so that no fixed or detachable connection is required.

[0090] The potting device for battery module comprises a mixing and discharging device for the potting material and at least a shunt pouring device. The shunt pouring device comprises a main pipe and two or more branch pipes. In a preferred embodiment of the present invention, the branch pipes comprise a rigid pipe fitting and a bendable flexible pipe connected to the rigid pipe fitting. The main pipe is connected to the bendable flexible pipe via the rigid pipe fitting. Preferably, the dimension of the outlet outer cross-section of the branch pipes is set so that the outlets of the branch pipes can be inserted into the gaps formed between the cells for pouring.

[0091] In the present invention, the inner diameters of each part of the main pipe are identical or different. Preferably, the inner diameters are the same or gradually decrease from the inlet to the outlet.

[0092] In the present invention, the inner diameters of each part of the branch pipes are identical or different. Preferably, the inner diameters are the same or gradually decrease from the inlet to the outlet.

[0093] In the present invention, the potting device for battery module may further include at least a raw material tank for storing and pre-mixing the potting material, which is respectively connected with the mixing and discharging device for the potting material.

[0094] In the present invention, a pump is arranged between the raw material tank and the mixing and discharging device for the potting material. The potting device for battery module may also not comprise a pump. In such a case, the raw material tank may be arranged above the discharging device for potting, and the potting material flows into the mixing and discharging device for the potting material by gravity.

[0095] In a preferred embodiment of the present invention, the potting device for battery module comprises a raw material tank A and a raw material tank B, which may be used to store the isocyanate component A and the isocyanate reactive component B respectively. Preferably, a pump is arranged between the raw material tank A and the mixing and discharging device for the potting material, and a pump is arranged between the raw material tank B and the mixing and discharging device for the potting material. In a preferred embodiment of the present invention, the potting device for battery module may also comprise a raw material tank C for storing and mixing a component of the potting material other than the isocyanate component A and the isocyanate reactive component B.

[0096] In a preferable embodiment of the present invention, the potting device for battery module comprises a raw material tank. The components of the potting material are pre-mixed in the raw material tank, and then fully mixed in the mixing and discharging device for the potting material.

[0097] In the present invention, mixing equipment used in the polyurethane processing industry can be used as the mixing and discharging device for the potting material. These equipment includes, but is not limited to single-component equipment, two-component equipment or multi-component equipment, preferably high-pressure two-component pouring equipment, including but not limited to HK135, HK270, HK450, HK540, HK650 high-pressure pouring machines from Hennecke GmbH or A- Compact 10, A-Compact 20, A-Compact 40, A-Compact 60, A-Compact 100, A-LAB 10H high- pressure pouring machines from Cannon S.p.A.

[0098] In the present invention, when the mixing and discharging device for the potting material is a pouring machine, the outlet of the mixing and discharging device for the potting material is generally the pouring gun head of the pouring machine. The Sout is the inner cross-sectional area of the pouring gun head of the pouring machine.

[0099] The potting material of the present invention may be selected from various common foam potting materials in the art, preferably polyurethane potting material.

[0100] The polyurethane potting material according to the present invention includes an isocyanate component A, an isocyanate reactive component B, and a foaming agent.

[0101] In terms of chemical structure, polyurethane is a polymer containing urethane repeat units. In the sense of the present invention, it includes the polyaddition products of polyfunctional isocyanates and polyols (sometimes, although not completely correct, also called polycondensation products). In addition to the basic polyurethane structure mentioned above, the polyurethane products usually comprise other structures, such as those with urea bond. The polyurethane with the basic polyurethane structure and these structures other than the pure basic polyurethane structure is also included in the scope of the polyurethane of the present invention, and does not deviate from the present invention. In the present invention, the term "isocyanate component" comprises one or more of all isocyanates known to those skilled in the art in polyurethane chemistry, especially such as toluene diisocyanate (TDI; prepared from toluene diamine TDA), diisocyanates and polyisocyanates of the diphenylmethane series (MDI; prepared from diamines and polyamines of diphenylmethane series MDA), pentane- 1,5 -diisocyanate (PDI; prepared from 1,5 -pentanediamine PDA), hexamethylene diisocyanate (HDI; prepared from 1,6-hexamethylene diamine HAD), 1,5 -naphthalene diisocyanate (NDI; prepared from 1,5 -naphthalene diamine ND A), isophorone diisocyanate (IPDI; prepared from isophorone diamine IPDA), p-xylylene diisocyanate (XDI; prepared from p-xylylene diamine XDA), methylcyclohexyl diisocyanate (HTDI), 4,4'-dicyclohexylmethane diisocyanate, p-phenylene diisocyanate (PPDI) or tetramethylxylylene diisocyanate (TMXDI).

[0102] The term "isocyanate" also comprises, of course, the embodiments of using two or more different isocyanates (such as a mixture of MDI and TDI) in the production of polyurethane. This is also the case for one isocyanate (thus it also applies to different MDI types, for example). All isocyanates for producing polyurethane are called together as the isocyanate component of polyurethane. The isocyanate component comprises at least one isocyanate. The isocyanate may comprise various isomers, such as TDI isomers 2,4- TDI and 2,6-TDI, or MDI isomers 2,4'-MDI and 4,4'-MDI.

[0103] In the present invention, the term "isocyanate reactive component B" comprises at least one polyol or consists of one or more polyols. All polyols for producing polyurethane are called together as the polyol component of polyurethane. The polyol component comprises at least one polyol. The term "polyol" includes all polyols known to those skilled in the art in polyurethane chemistry, especially polyether polyols, polyester polyols, polyether ester polyols and polyether carbonate polyols. The expression "polyol" also comprises the embodiments of using two or more different polyols in the production of polyurethane. This is also the case for one polyol. Therefore, where, for example, "polyether polyol" (or "polyester polyol", etc.) is mentioned below, the term also comprises the embodiments of using two or more different polyether polyols (or two or more different polyester polyols, etc.) in the production of polyurethane.

[0104] Polyether polyols can be prepared by a known process, for example, by reacting an olefin oxide with a starter in the presence of a catalyst. The catalyst includes, but is not limited to, alkaline hydroxides, alkaline alkoxides, antimony pentachloride, boron trifluoride diethyl etherate, or a combination thereof. The olefin oxide includes, but is not limited to, tetrahydrofuran, ethylene oxide, propylene oxide, 1,2-butylene oxide, 2,3 -butylene oxide, styrene oxide, or a combination thereof, particularly preferably ethylene oxide and / or propylene oxide. The starter may be adjusted according to the properties of the polyether polyols, such as, functionality and viscosity, but preferably is not limited to polyhydroxy compounds or polyamino compounds. The polyhydroxy compounds include, but are not limited to sorbitol, water, ethylene glycol, 1,2-propanediol, 1,3 -propanediol, diethylene glycol, trimethylolpropane, glycerin, bisphenol A, bisphenol S, or a combination thereof. Polyamino compounds include, but are not limited to, ethylene diamine, propylene diamine, butylene diamine, hexamethylene diamine, diethylene triamine, toluene diamine, or combinations thereof. The molecular weight of the polyether polyols may be within the conventional range of polyether polyols used in polyurethane potting materials in this field, preferably 200-20000, more preferably 200- 10000, wherein the molecular weight is determined by GPC high-performance liquid chromatography, and the testing method is in accordance with GB / T 21863-2008. The functionality of the polyether polyols is preferably of 2-6. The hydroxyl value of the polyether polyols is preferably 16-1200 mg KOH / g. The hydroxyl value refers to the number of milligrams of potassium hydroxide equivalent to the hydroxyl group in 1g of the sample, wherein the test method is in accordance with ISO 14900-2017.

[0105] Polyester polyols may be aliphatic or aromatic polyester polyols, preferably aliphatic polyester polyols. The polyester polyols may be prepared by reacting a dicarboxylic acid or a dicarboxylic acid anhydride with a polyol. The dicarboxylic acid includes, but is not limited to, aliphatic carboxylic acids containing 2-12 carbon atoms. The aliphatic carboxylic acids containing 2-12 carbon atoms include, but are not limited to, succinic acid, malonic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, or a combination thereof. The dicarboxylic acid anhydride includes, but is not limited to, phthalic anhydride, tetrachlorophthalic anhydride, maleic anhydride, or a combination thereof. The polyol reacted with the dicarboxylic acid or the dicarboxylic acid anhydride includes, but is not limited to, ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3 -propanediol, dipropylene glycol, 1,3-methyl propylene glycol, 1,4-butanediol, 1,5 -pentanediol, 1,6-hexanediol, neopentyl glycol, 1,10-decanediol, glycerol, trimethylolpropane, or a combination thereof. The polyester polyols may also include those prepared from lactones. The polyester polyols prepared from lactones are preferably, but not limited to, e-caprolactone. The molecular weight of the polyester polyols may be within the conventional range of polyester polyols used in polyurethane potting materials in this field, preferably 200-6000, more preferably 200-5000, wherein the molecular weight is determined by GPC high-performance liquid chromatography, and the testing method is in accordance with GB / T 21863-2008. The functionality of the polyether polyols is preferably of 2-4. The hydroxyl value of the poly ether polyols is preferably 18-800 mg KOH / g. The hydroxyl value refers to the number of milligrams of potassium hydroxide equivalent to the hydroxyl group in 1g of the sample, wherein the test method is in accordance with ISO 14900-2017. The polyurethane potting material comprises one or more foaming agents, including but not limited to water, fluorocarbons, hydrochlorocarbons, chlorofluorocarbons, hydrofluorocarbons and hydrocarbons, preferably water.

[0106] In the present invention, the volume ratio of the isocyanate component A and the isocyanate reactive component B in the potting material is preferably 1:10-10:1, more preferably 5: 1-1: 5, for example 3:1, 2:1, 1:1, 1:2 and 1:3.

[0107] In the present invention, the isocyanate component A or the isocyanate reactive component B may also comprises various conventional additives in the art, including but not limited to catalysts, foam stabilizers, light stabilizers, crosslinking agents, antioxidants, pore formers, coloring agents, fillers, flame retardants, anti-smoke agents, antistatic agents, diluents, coupling agents, surface wetting agents, leveling agents, thixotropic agents, plasticizers, foam homogenizing agents, free radical reaction inhibitors or a combination thereof.

[0108] In a preferred embodiment of the present invention, the isocyanate component A and / or the isocyanate reactive component B may comprise a flame retardant. When the battery module is applied without needing to meet the flame retardant requirements, it may not comprise a flame retardant. The flame retardant may include various conventional flame retardants in the field, including but not limited to, additive flame retardants and reactive flame retardants.

[0109] For example, flame retardants based on phosphorus may be used, such as phospholinoxides, phosphinates, phosphonates, phosphazenes, or phosphates, e.g. diethylethylphosphonate (DEEP), triethyl phosphate (TEP), triaryl phosphates such as triphenyl phosphate (TPP), tricresyl phosphate, diphenylcresyl phosphate (DPK), bisphenol A bis(diphenyl phosphate) (BDP), resorcinyl diphosphate (RDP) and tert-butylphenyl diphenyl phosphate. Halogenated phosphate flame retardants are also flame retardants commonly used in polyurethane foams, e.g. chlorinated phosphates such as tris(2-chloroethyl) phosphate, tris(2-chloropropyl) phosphate (TCPP), tris(l,3- dichloropropyl) phosphate, tris(2, 3 -dibromopropyl) phosphate, tetrakis(2-chloroethyl)ethylene diphosphate, as well as commercially available halogenated flame retardant polyols. Most of the halogenated phosphates are liquid at room temperature and well compatible with polyols, including tris(2-chloropropyl)phosphate (TCPP), tris(2-chloroethyl)phosphate (TCEP), tris(dichloropropyl)phosphate (TDCPP), tris(dibromopropyl)phosphate, tetrakis(2-chloroethyl) ethylene diphosphate, bis[di(2-chloroethyl)]diethylene glycol phosphate, 2,2-dimethyl-3- chloropropylbis(l,3-dichloro-2 -propyl) phosphate, 2,2-dimethyl-3-bromo-propyl-P-bromoethyl phosphoric acid, diphosphates or polyphosphates. The flame retardants may also be phosphonate flame retardants, including dimethyl methylphosphonate (DMMP), diethyl ethylphosphonate, dimethyl propylphosphonate, triisopropyl phenyl phosphate, triethyl phosphate, etc. Inorganic solid flame retardants may also be used in the present invention, such as melamine and its derivatives, red phosphorus and its complexes, aluminum hydroxide powder and the like. The content of flame retardants in the system generally needs to reach a certain amount to achieve the flame retardant effect. The flame retardant is preferably used in an amount of 5-50 % by weight, preferably 15-40 % by weight, relative to the potting material.

[0110] The polyurethane potting material of the present invention may be foamed to form flexible polyurethane foams or rigid polyurethane foams. The foams may have a density of 100-600 kg / m3, preferably 150-500 kg / m3.

[0111] The present invention also provides a method for potting a battery module, in which

[0112] (i) a casing and a number of number of cells arranged in the casing with gaps and spaces between them is provided,

[0113] (ii) a potting material is poured into a part of the gaps between the cells and / or a part of the spaces between the cells and the casing of the battery module by using a potting device for battery module of the present application, and the poured potting material flows to all the residual gaps and spaces, and

[0114] (iii) the potting material is foamed and cured, , wherein preferably, the number of gaps and spaces where the potting material is poured into is equal to the number of the outlets of the branch pipes of the potting device for a battery module.

[0115] In a preferred embodiment of the present invention, the method for potting a battery module comprises inserting the branch pipes into a part of the gaps and spaces between the cells and / or a part of the gaps and spaces between the cells and the casing of the battery module by using the potting device for a battery module of the present invention, and, , the potting material flows to all the residual gaps and spaces, the potting material is foamed and cured, wherein preferably, the number of gaps and spaces where the potting material is poured into is equal to the number of the outlets of the branch pipes of the potting device for battery module .

[0116] In the present invention, the pouring step can be repeated according to the actual size of the battery module, to allow the potting material to flow to all gaps and spaces. The total number of the aforementioned gaps and spaces to be filled does not need to be equal to the number of the outlets of the branch pipes, it can be a multiple of the outlets of the branch pipes.

[0117] In the present invention, the position where the potting material is poured with the branch pipe is called the pouring point. When the branch pipe is inserted into the gap and / or space, the insertion point is the pouring point. When it is poured with the branch pipe from above the cells, the position where the potting material is poured is the pouring point. The pouring point may be selected according to the design of the battery module, the number and layout of the cells. Usually, the more cells there are, the more pouring points are present, which ensures that the potting material can flow to each gap and space. The number of pouring points in the present invention may be 2-100, preferably 2-50, more preferably 2-30.

[0118] In a preferred embodiment of the present invention, a method for potting a battery module is provided, wherein

[0119] (i) a casing and a number of cells arranged in the casing with gaps and spaces between them is provided,

[0120] (ii) the cells are covered on their upper surfaces with at least a cover plate having at least one through-hole located above a gap or space to be fdled, and the lower surface of the cover plate is the surface which is in contact with the cells, and

[0121] (iii) a potting material is poured through the through-holes into a part of the gaps between the cells and / or into a part of the spaces between the cells and the casing of the battery module by using a potting device for a battery module of the present invention, and

[0122] (iv) the poured potting material flows to all the residual gaps and spaces, and

[0123] (v) the potting material is foamed and cured, wherein preferably, the number of gaps and spaces where the potting material is poured into is equal to the number of through-holes, and / or, is equal to the number of the outlets of the branch pipes of the potting device for battery module, and / or preferably, before the curing is completed, the cover plate is kept from displacing in its vertical direction z. The vertical direction z refers to the direction perpendicular to the upper surface or lower surface of the cover plate.

[0124] In the above preferred embodiments, the potting material is discharged from the mixing and discharging device at an output flow rate greater than or equal to lOOg / s, preferably 100g / s-250g / s, more preferably 100g / s-200g / s.

[0125] In a preferred embodiment of the present invention, the method for potting a battery module comprises the following steps:

[0126] (1) placing all the cells in the casing of the battery module, leaving gaps between the cells, and leaving spaces between the cells and the casing;

[0127] (2) covering the upper surfaces of the cells with at least one cover plate, the cover plate having a number of through-holes equal to the number of outlets of the branch pipes;

[0128] (3) inserting the outlets of the branch pipes through the through-holes into a part of the gaps and / or a part of the spaces, and then pouring the potting material; or place the outlets of the branch pipes above the through-holes, and then pouring the potting material so that the potting material flows into a part of the gaps and / or a part of the spaces through the through-holes; wherein the potting material is output from the mixing and discharging device at an output flow rate greater than or equal to lOOg / s, preferably 100g / s-250g / s, more preferably 100g / s-200g / s, and is poured into a part of the gaps and / or a part of the spaces through the outlets of the branch pipes;

[0129] (4) the poured potting material flows to all the residual gaps and spaces, the poured potting material is foamed and cured, and,

[0130] (5) preferably, the cover plate is removed; wherein, during the time period from the completion of pouring in step (3) to the completion of curing in step (4), a pressure is constantly applied onto the cover plate, so that the cover plate is kept from displacing in its vertical direction (z) during this time period. In another preferred embodiment of the present invention, the method for potting a battery module comprises, after pouring the potting material, covering at least one cover plate on the upper surface of the cells, and applying a pressure onto the cover plate, so that the cover plate is kept from displacing in its vertical direction before the completion of curing.

[0131] In a more preferable embodiment of the present invention, the method for potting a battery module comprises the following steps:

[0132] (1) placing all the cells in the casing of the battery module, leaving gaps between the cells, and leaving spaces between the cells and the casing;

[0133] (2) inserting the outlets of the branch pipes into a part of the gaps and / or a part of the spaces, and then pouring the potting material; or placing the outlets of the branch pipes above a part of the gaps and / or a part of the spaces, and then pouring the potting material, so that the potting material flows into a part of the gaps and / or a part of the spaces, covering the upper surfaces of the cells with at least one cover plate, the cover plate has no through-holes; wherein, the potting material is output from the mixing and discharging device at an output flow rate greater than or equal to lOOg / s, preferably 100g / s-250g / s, more preferably 100g / s-200g / s, and poured through the outlets of the branch pipes into a part of the gaps and / or a part of the spaces;

[0134] (3) the poured potting material flows into all the residual gaps and spaces, the potting material is foamed and cured, and

[0135] (4) preferably, the cover plate is removed; wherein, during the time period from the completion of the pouring in step (2) to the completion of the curing in step (3), a pressure is continuously applied onto the cover plate, so that the cover plate is kept from displacing in its vertical direction z during this time period.

[0136] In a more preferable embodiment of the present invention, the number of through -holes is 2-100, more preferably 2-50, and most preferably 2-30.

[0137] In a preferred embodiment of the present invention, if the outlet part of the branch pipes or the part of the branch pipes comprising the outlet is a bendable flexible pipe, the bendable flexible pipe is inserted into the pouring port. In the present invention, high-pressure gas may be introduced into the intake pipe on the main pipe and / or the branch pipes, after pouring is completed. The pressure of the high-pressure gas is preferably of 2-20 bar, more preferably 8-15 bar, and the gas flow rate is preferably of 5-50 Nm3 / h, more preferably 30-50 Nm3 / h. The step of introducing high-pressure gas does not affect the flow, foaming or curing of the potting material, and may or may not be performed at the same time.

[0138] In a more preferred embodiment of the present invention, one pouring point is set for every 10-50 cells, and more preferably one pouring point is set for every 20-40 cells.

[0139] In another embodiment of the present invention, the method for potting a battery module comprises pouring the potting material at a position above several cells downward via each branch pipes by using the potting device for battery module of the present invention, the poured potting material flows to all gaps and spaces and be foamed and cured. The position “above” refers to the upper space of any cells, indicating the upper and lower position relationship of the branch pipes and the cells. It is not required to be directly above the cell, but may be left above, right above, or diagonally above. This method can be used for battery modules where the cells are completely encapsulated, which can significantly improve the potting efficiency.

[0140] The present invention also provides a battery module comprising a casing and a number of cells arranged in the casing. There is the cured potting material, i.e., the polyurethane foam, obtained by the method for potting a battery module according to the present invention between the cells and between the cells and the casing. The height of the cured potting material is preferably less than or equal to the height of the cells, so that there is no potting material on the upper surface of the cells, thereby reducing the possibility of short circuit of the cells.

[0141] In the present invention, the battery module preferably further comprises an upper cover.

[0142] The number of the cells in the battery module is preferably 10-1000, more preferably 100-900. The spacing between adjacent cells is preferably 0.5-10 mm, preferably 0.5-5 mm.

[0143] The present invention also provides an electric vehicle comprising at least one battery module of the present invention.

[0144] The existing potting devices cannot perform multi-station potting simultaneously. When the size of the pouring gun head is small, it is accordingly necessary to use a low flow pouring machine, which is not suitable for use in the field of electric vehicles having an increasing number of cells. The potting device for battery module of the present invention can achieve fast and efficient pouring, and ensure that the pouring of the potting material is completed before the foaming begins. The present invention adopts a bendable flexible pipe as the pouring port, which may be widely applied to various cell designs, has low cost for replacement, can be applied flexibly, and avoids damage to the cells when colliding therewith. By controlling the ratio of the cross-sectional areas of the outlet of the branch pipes and the outlet of the main pipe, it can be ensured that the cured potting material obtained by pouring, i.e., the polyurethane foam, has consistent height, good uniformity, no defects such as bubbles and blisters, and the pouring efficiency is greatly improved.

[0145] Examples

[0146] The present invention is further described in combination with specific examples. However, it should be understood that these examples are only used to illustrate the present invention and do not limit the scope of the present invention.

[0147] The test methods without specific conditions in the following examples are usually carried out according to the conventional conditions or the conditions recommended by manufacturers. Unless stated otherwise, percentages and parts used herein are by weight.

[0148] Materials, instruments and test methods

[0149] Component A is Desmodur 44V20 (polymeric MDI) from Covestro;

[0150] Component B is Baysafe BEF (polyol formulation) from Covestro.

[0151] Mixing and discharging device for the potting material:

[0152] HK135 from Hennecke GmbH, with a pouring flow rate of 100 g / s or more, an outer diameter of 18 mm, an inner diameter of 12 mm, and an inner cross-sectional area of 113.04 mm2for the pouring gun head; wherein the pouring gun head is the outlet of the mixing and discharging device for the potting material.

[0153] HK270 from Hennecke GmbH, with a pouring flow rate of 200 g / s, an outer diameter of 40 mm, an inner diameter of 18 mm, and an inner cross-sectional area of 254.34mm2for the pouring gun head; wherein the pouring gun head is the outlet of the mixing and discharging device for the potting material.

[0154] A-LAB 10H from Cannon S.p.A., with a pouring flow rate of 120 g / s, an outer diameter of 15 mm, an inner diameter of 10 mm, and an inner cross-sectional area of 78.5 mm2for the pouring gun head; wherein the pouring gun head is the outlet of the mixing and discharging device for the potting material.

[0155] Cream time: The difference in time from the beginning of the mixing of the polyol-containing component and the polyisocyanate component (counted as 0 second) to the beginning of the polyurethane composition becoming milky white.

[0156] Gel time: The time period from the beginning of the mixing of the polyol-containing component and the polyisocyanate component (counted as 0 second) to the curing of polyurethane composition (until the composition begins to become viscous and a filamentous material can be pulled out upon contacting with a rod-shaped solid).

[0157] Tack free time: The time from the beginning of the mixing of the polyol-containing component and the poly isocyanate component until the surface of the foam no longer feels tacky.

[0158] Viscosity: measured at 25°C according to DIN 53019-1-3.

[0159] Free foam density: tested according to ISO845. Molded density: tested according to ASTM C303.

[0160] Compressive strength: tested according to A STM DI 621.

[0161] Tensile strength: tested according to DIN53571.

[0162] Tensile elongation at break: tested according to DIN53571.

[0163] Flame retardant grade: tested according to UL94, sample thickness = 7 mm.

[0164] As shown in Fig.1, a potting device for battery module according to the present invention comprises a raw material tank A 130, a raw material tank B 140, a mixing and discharging device for the potting material 110, a shunt pouring device and a cover plate 190. The raw material tank A and raw material tank B are connected respectively with the mixing and discharging device for the potting material 110 via a pump 150 arranged downstream. The shunt pouring device comprises at least one main pipe and two branch pipes. The main pipe is connected with the branch pipes respectively. The shunt pouring device is connected with the mixing and discharging device for the potting material 110 via the main pipe. The shunt pouring devices 100, 200, 300, 400, 500, 600, 700, and 800 may have structures as shown in Figs. 1-8. The main pipe and the branch pipes may be provided with an intake pipe having an inlet valve, which is not shown in the figure, so as to introduce high-pressure gas into the main pipe or the branch pipes for cleaning the main pipe or the branch pipes.

[0165] Example 1

[0166] The potting device for battery module as shown in Fig.1 is used. The mixing and discharging device for the potting material 110 is HK135, wherein the shunt pouring device 100 has a main pipe 115 and two branch pipes as shown in Fig. 1. Each branch pipe comprises a rigid pipe fitting 120 and a bendable flexible pipe 160 connected with each other. Each rigid pipe fitting is right-angled bended. The outlet inner cross-sectional area of the bendable flexible pipe 160 of each branch pipe is 8.5 mm2, E 81,,.,,,,!,= 17mm2. The outlet inner cross-sectional area of the main pipe is 113 mm2. The main pipe is fixedly connected to the pouring gun head of the mixing and discharging device for the potting material and the branch pipes respectively. The bendable flexible pipe 160 and the rigid pipe fitting 120 are self-locking connected. The total lengths of the two branch pipes are the same.

[0167] Example 2

[0168] A potting device for battery module as shown in Fig.l is used. The mixing and discharging device for the potting material 110 is HK135. The shunt pouring device 100 is replaced by a shunt pouring device 200. The shunt pouring device 200 as shown in Fig.2 comprises a main pipe 215 and two branch pipes. Each branch pipe comprises a rigid pipe fitting 220 and a bendable flexible pipe 260. An intake pipe (not shown) is provided on the main pipe. The rigid pipe fittings 220 are semi-n shaped respectively and have the same pipe diameter, and are distributed axisymmetrically with the central line of the main pipe 215 as the axis. The bendable flexible pipes 260 are polyolefin hoses. The outlet inner cross-sectional area of the bendable flexible pipes 260 of the branch pipes is 50.5 mm2, E Sbranch=101mm2, . The outlet inner cross-sectional area of the main pipe 215 is 113 mm2. The inner diameter of the main pipe decreases stepwise from the inlet to the outlet. The main pipe is fixedly connected to the pouring gun head of the mixing and discharging device for the potting material and the branch pipes respectively. The clamped connection is applied between the bendable flexible pipes 260 and the rigid pipe fittings 220. The two rigid pipe fittings 220 have the same length. The two bendable flexible pipes 260 have the same length. The main pipe and branch pipes of the shunt pouring device may have different cross-sectional shapes, pipe fitting shapes and pipe diameters.

[0169] Example 3

[0170] A potting device for battery module as shown in Fig.l is used. The mixing and discharging device for the potting material 110 is HK270. The shunt pouring device 100 is replaced by the shunt pouring device 300. The shunt pouring device 300 as shown in Fig. 3 comprises a main pipe 315 and two branch pipes. Each branch pipe comprises a rigid pipe fitting 320 and a bendable flexible pipe 360. The rigid pipe fittings 320 are in a straight tubular shape and have the same pipe diameter, and are distributed axisymmetrically with the central line of the main pipe 315 as the axis. The bendable flexible pipes 360 are TPU hoses. The outlet inner cross-sectional area of the bendable flexible pipes 360 of the branch pipes is 78.5 mm2, E Sbranch=157mm2. The outlet inner cross-sectional area of the main pipe 315 is 254 mm2. The inner diameter of the main pipe decreases gradually from the inlet to the outlet. The main pipe is fixedly connected to the branch pipes. The bendable flexible pipes 360 and the rigid pipe fittings 320 are self-locking connected. The lengths of the two rigid pipe fittings 320 are the same. The lengths of the two bendable flexible pipes 360 are the same. They may be adjusted as desired. The main pipe and the branch pipes of the shunt pouring device may have different cross-sectional shapes, pipe fitting shapes and pipe diameters. The angle between the rigid pipe fittings and the central line of the main pipe may be adjusted within a range of 0-90° according to actual needs.

[0171] Example 4

[0172] A potting device for battery module as shown in Fig.l is used. The mixing and discharging device for the potting material 110 is A-LAB 10H. The shunt pouring device 100 is replaced by the shunt pouring device 400. The shunt pouring device 400 is a four-way pipe, as shown in Fig. 4. It comprises a main pipe 415 and three branch pipes. Each branch pipe comprises a rigid pipe fitting 420 and a bendable flexible pipe 460 connected with each other. The rigid pipe fittings 420 are in a straight tubular shape and have the same pipe diameter, and are distributed radially with the central line of the main pipe 415 as the axis. The bendable flexible pipes 460 are PE hoses. The outlet inner cross- sectional area of the bendable flexible pipes 460 of the branch pipes is 20 mm2, E Sbranch=60mm2. The outlet inner cross-sectional area of the main pipe 415 is 79 mm2. The main pipe is fixedly connected to the branch pipes. The clamped connection is applied between the bendable flexible pipes 460 and the branch pipes 420. The lengths of the three rigid pipe fittings 420 are the same. The lengths of the three bendable flexible pipes 460 are the same. They may be adjusted as desired. The main pipe and the branch pipes of the shunt pouring device may have different cross-sectional shapes, pipe fitting shapes and pipe diameters. The angle a formed by the projection of adjacent rigid pipe fittings on the horizontal plane may be adjusted according to actual needs. The angle a is preferably the same as each other. The angle between the rigid pipe fittings and the main pipes may be adjusted within a range of 0-90° according to actual needs.

[0173] Example 5

[0174] A potting device for battery module as shown in Fig.l is used. The mixing and discharging device for the potting material 110 is HK270. The shunt pouring device 100 is replaced by the shunt pouring device 500. The shunt pouring device 500 is a five-way pipe, as shown in Fig. 5. It comprises a main pipe 515 and four branch pipes. Each branch pipe comprises a rigid pipe fitting 520 and a bendable flexible pipe 560. The rigid pipe fitting 520 is provided with an intake pipe 570. A valve (not shown) is provided on the intake pipe 570. The rigid pipe fittings 520 are in a straight tubular shape and have the same pipe diameter, and are distributed axisymmetrically with the central line of the main pipe 515 as the axis. The bendable flexible pipes 560 are polyurethane TPU hoses. The outlet inner cross- sectional area of the bendable flexible pipes 560 of the branch pipes is 52.8 mm2, E Sbranch=211.2mm2. The outlet inner cross-sectional area of the main pipe 515 is 254 mm2. The clamped connection is applied between the main pipe and the branch pipes. The bendable flexible pipes 560 and the rigid pipe fittings 520 are self-locking connected. The lengths of the four bendable flexible pipes 560 are the same. The lengths of the four rigid pipe fittings 520 are the same. They may be adjusted as desired. The main pipe and the branch pipes of the shunt pouring device may have different cross-sectional shapes, pipe fitting shapes and pipe diameters. The angles a and a' formed by the projection of the rigid pipe fittings on the horizontal plane may be adjusted according to actual needs. The angle a' and a are preferably the same. The angles between the rigid pipe fittings and the main pipe may be adjusted within a range of 0-90° according to actual needs.

[0175] Example 6 A potting device for battery module as shown in Fig.l is used. The mixing and discharging device for the potting material 110 is HK270. The shunt pouring device 100 is replaced by the shunt pouring device 600. The shunt pouring device 600 is a five-way pipe, as shown in Fig. 6. It comprises a main pipe 615 and four branch pipes. Each branch pipe comprises rigid pipe fittings 620 and 620'. Each rigid pipe fitting 620 is further connected with two rigid pipe fittings 620' respectively. The rigid pipe fittings 620 are in a right-angled bended tubular structure and have the same pipe diameter, and are distributed axisymmetrically with the central line of the main pipe 615 as the axis. The rigid pipe fittings 620' are distributed axisymmetrically with the central line of the rigid pipe fitting 620 as the axis. The rigid pipe fittings 620' are in a right-angled bended tubular structure and have the same pipe diameter. The pipe diameter thereof gradually narrows at the position close to the outlet of the rigid pipe fitting 620' in the direction of the outlet. The outlet inner cross-sectional area of the rigid pipe fittings 620' is 32.2 mm2, Ebranch=128.8mm2. The outlet inner cross-sectional area of the main pipe 615 is 254 mm2. The clamped connection is applied between the main pipe and the branch pipes. The lengths of the two rigid pipe fittings 620 are the same. The lengths of the four rigid pipe fittings 620' are the same. They may be adjusted as desired. The main pipe and the branch pipes of the shunt pouring device may have different cross-sectional shapes, pipe fitting shapes and pipe diameters.

[0176] Example 7

[0177] A potting device for battery module as shown in Fig.l is used. The mixing and discharging device for the potting material 110 is HK270. The shunt pouring device 100 is replaced by the shunt pouring device 700. The shunt pouring device 700 is a nine-way pipe, as shown in Fig.7. It comprises a main pipe 715 and eight branch pipes. Each branch pipe comprises rigid pipe fittings 720, 720' and bendable flexible pipes 760. The four branch pipe fittings 720' are integrated and are connected with the rigid pipe fittings 720. The rigid pipe fittings 720 are distributed axisymmetrically with the central line of the rigid pipe fitting 715 as the axis, or may not be distributed symmetrically. The bendable flexible pipes 760 are polyurethane TPU hoses. The outlet inner cross-sectional area of the bendable flexible pipes 760 of the branch pipes is 19.6 mm2, E Sbranch=1 6.8mm2. The outlet inner cross- sectional area of the main pipe 715 is 254 mm2. The main pipe and the rigid pipe fittings 720 are integrally molded. The rigid pipe fittings 720 and 720' are detachably connected. The bendable flexible pipes 760 and the rigid pipe fittings 720' are self-locking connected. The lengths of the two rigid pipe fittings 720 are the same. The lengths of the four rigid pipe fittings 720' are the same. The lengths of the four bendable flexible pipes 760 are the same. They may be adjusted as desired. The main pipe and the branch pipes of the shunt pouring device may have different cross-sectional shapes, pipe fitting shapes and pipe diameters. Example 8

[0178] A potting device for battery module as shown in Fig.l is used. The mixing and discharging device for the potting material 110 is HK270. The shunt pouring device 100 is replaced by the shunt pouring device 800. The shunt pouring device 800 is a seven-way pipe, as shown in Fig. 8a and 8b. It comprises a main pipe 815 and six branch pipes. Each branch pipe comprises rigid pipe fittings 820 and bendable flexible pipes 860 connected with each other. In Fig. 8a, the six rigid pipe fittings 820 are integrated and are connected with the main pipe 815. In Fig. 8b, the six rigid pipe fittings 820 are formed by producing six through-holes on a solid part 870 that is connected with the main pipe 815. The rigid pipe fittings 820 are distributed axisymmetrically with the central line of the rigid pipe fitting 815 as the axis, or may not be distributed symmetrically. The bendable flexible pipes 860 are polyester hoses. The outlet inner cross-sectional area of the bendable flexible pipes 860 of the branch pipes is 13.8 mm2, E Sbranch=82.8mm2. The outlet inner cross-sectional area of the main pipe 815 is 254 mm2. The slot connection is applied between the main pipe and the rigid pipe fittings 820. The clamped connection is applied between the bendable flexible pipes 860 and the rigid pipe fittings 820. The lengths of the six rigid pipe fittings 820 are the same. The lengths of the six bendable flexible pipes 860 are different. The length difference between the longest and the shortest bendable flexible pipes 860 is 30% of the sum of the lengths of the shortest bendable flexible pipe and any of the rigid pipe fittings. But the lengths of the six bendable flexible pipes 860 may be adjusted to be the same as desired. The main pipe and the branch pipes of the shunt pouring device may have different cross-sectional shapes, pipe fitting shapes and pipe diameters.

[0179] Example 9

[0180] (1) 128 cells were placed in the casing 170 of the battery module 1 with the gaps between the cells having a spacing 1 of 1.5mm. Fig. 9 and 10 show a partial schematic view of the battery module, while the rest cells are not shown,

[0181] (2) An aluminum composite plate (composite plate of a silicone foam board with a thickness of 1cm and an aluminum sheet, the surface of silicone foam in contact with the upper surfaces of cells) with six through-holes was used to cover all cells,

[0182] (3) By using the potting device for a battery module described in Example 8, potting materials Component A and Component B according to Table 1 were transferred from the raw material tank A and the raw material tank B to the mixing and discharging device for the potting material HK270 via a pump 150. The raw materials were mixed in the mixing and discharging device for the potting material and delivered to the shunt pouring device at a flow rate of 200 g / s. All bendable flexible pipes 860 in the shunt pouring device were inserted into the 6 gaps between the cells through the through-holes in the aluminum composite plate. The positions indicated by the arrows in Fig. 10 refer to two of the gaps, i.e., the pouring ports. The mixed potting material was poured into the pouring ports by the shunt pouring device. The pouring height was smaller than the height of the cells. The bendable flexible pipes were removed, after the pouring was completed. A pressure was applied onto the aluminum composite plate to make the plate be kept from displacing,

[0183] (4) The potting material flowed to all gaps and spaces, was foamed and cured. The aluminum composite plate was removed.

[0184] A photo of the battery module obtained after potting is shown in Fig. 12. There are no bubbles and defects between the cells and the cured potting material. The cured potting material has a uniform height and a flat surface. There is no potting material on the cells. The potted battery module is divided into four regions on average. The molded densities pl, p2, p3 and p4 of the foam in the regions are tested respectively (each region tested 3 times for the average value). The average value of the molding density in the four regions is calculated as p, Thedifferencebetween the maximum density and the minimum density among pl, p2, p3 and p4 is lower than 10% of the average molding density p, which means that the foam density in each potting region is uniform, and there will be no subsequent foam shrinkage in the cells.

[0185] Table 1 Example 10

[0186] (1) 8x8 cells were placed in the casing of the battery module 1 with the gaps between the cells having a spacing 1 of 1.5mm,

[0187] (2) By using the potting device for a battery module described in Example 1, potting materials Component A and Component B according to Table 1 were transferred from raw material tank A and raw material tank B to the mixing and discharging device for the potting material HK135 via a pump 150 respectively. The components of the potting material were mixed in the mixing and discharging device for the potting material and were delivered to the shunt pouring device at a speed of 120g / s. The potting material was poured downwards by the two bendable flexible pipes in the shunt pouring device above the gaps. The pouring height was smaller than the height of the cells. The bendable flexible pipes were removed, after the pouring was completed. A polyurethane foam board with a polyethylene fdm layer was used to cover the cells. A pressure was applied onto the polyurethane foam board so that the polyurethane foam board was kept from displacing in the vertical direction z; wherein, the thickness of the polyurethane foam board is 3mm, and the polyethylene film layer was in contact with the cells.

[0188] (3) High-pressure gas was introduced into the intake pipe of the main pipe with a pressure of 12 bar and a gas flow rate of 20 Nm3 / h.

[0189] (4) The potting material flowed to all gaps and spaces, was foamed and cured. The polyurethane foam board was removed.

[0190] The step (3) and the step (4) were not in particular order and may also be performed simultaneously.

[0191] In the battery module obtained after potting, there are no bubbles and defects between the cells and the cured potting material. The cured potting material has a flat surface and is uniform in height. There is no potting material on the cells. The potted battery module is divided into four regions on average. The molded densities of the foam in the regions are tested respectively (each region tested 3 times for the average value). Among the molded densities of the four regions, the difference between the maximum density and the minimum density is lower than 10% of the average molding density p, which means that the foam density in each potting region is uniform, and there will be no subsequent foam shrinkage in the cells.

[0192] The potting device for battery module Example 10 is replaced by the potting device in Examples 2- 3, wherein the flow rate of the mixing and discharging device for the potting material in Example 2 is 120g / s, and that in Example 3 is 200 g / s. A battery module with good potting effect is also obtained. There are no bubbles and defects between the cells and the cured potting material. The cured potting material is uniform in height and is flat. The potted battery module is divided into four regions on average. The molded densities of the foam in the regions are tested respectively (each region tested 3 times for the average value). Among the molded densities of the four regions, the difference between the maximum density and the minimum density is lower than 10% of the average molding density p, which means that the foam density in each potting region is uniform, and there will be no subsequent foam shrinkage in the cells.

[0193] Example 11

[0194] (1) 256 cells were placed in the casing of the battery module 1 with the gaps between the cells having a spacing 1 of 1.5mm. Fig.11 shows a partial schematic view of the battery module, while the rest cells are not shown,

[0195] (2) An aluminum composite plate (composite plate of polyethylene foam board with a thickness of 2cm and an aluminum sheet, the surface of polyethylene foam board in contact with the upper surfaces of cells) with eight through-holes was used to cover all cells,

[0196] (3) By using the potting device for a battery module described in Example 7, potting materials Component A and Component B according to Table 1 were transferred from raw material tank A and the raw material tank B to the mixing and discharging device for the potting material HK270 via a pump 150. The raw materials were mixed in the mixing and discharging device for the potting material and delivered to the shunt pouring device at a speed of 200 g / s. All bendable flexible pipes 760 in the shunt pouring device were inserted into the eight gaps between the cells through the through-holes in the aluminum composite plate, i.e., the pouring ports. The position indicated by the arrow in Fig. 11 refers to one of the pouring ports. The mixed potting material was poured into the eight gaps by the shunt pouring device. The pouring height was smaller than the height of the cells. The bendable flexible pipe was removed, after the pouring was completed. A pressure was applied onto the aluminum composite plate so that the aluminum composite plate was kept from displacing in the vertical direction z,

[0197] (4) The potting material flowed to all gaps and spaces, was foamed and cured. The aluminum composite plate was removed.

[0198] In the battery module obtained after potting, there are no bubbles and defects between the cells and the potting material. The cured potting material is uniform in height and is flat on the surface. There is no potting material on the cells. The potted battery module is divided into four regions on average. The molded densities of the foam in the regions are tested respectively (each region tested 3 times for the average value). Among the molded densities of the four regions, the difference between the maximum density and the minimum density is lower than 10% of the average molding density p, which means that the foam density in each potting region is uniform, and there will be no subsequent foam shrinkage in the cells. Example 12

[0199] (1) 128 cells were placed in the casing of the battery module 1 with the gaps between the cells having a spacing 1 of 1.5mm,

[0200] (2) An aluminum composite plate (composite plate of silicone foam board with a thickness of 1cm and an aluminum sheet, the surface of silicone foam board in contact with the upper surfaces of cells) with four through-holes was used to cover all cells,

[0201] (3) By using the potting device for a battery module described in Example 6, potting materials Component A and Component B according to Table 1 were transferred from the raw material tank A and the raw material tank B to the mixing and discharging device for the potting material HK270 via a pump 150. The raw materials were mixed in the mixing and discharging device for the potting material and delivered to the shunt pouring device at a flow rate of 200 g / s. All branch pipes 620' in the shunt pouring device were inserted into the four gaps between the cells through the through-holes in the aluminum composite plate, i.e., the pouring ports. The mixed potting material was poured into the pouring ports by the shunt pouring device. The pouring height is smaller than the height of the cells. The shunt pouring device was removed, after the pouring was completed. A pressure was applied onto the aluminum composite plate so that the aluminum composite plate was kept from displacing in the vertical direction z,

[0202] (4) The potting material flowed to all gaps and spaces, was foamed and cured. The aluminum composite plate was removed.

[0203] A battery module with good potting effect is also obtained. There are no bubbles and defects between the cells and the potting material. The cured potting material is uniform in height and is flat on the surface. There is no potting material on the cells. The potted battery module is divided into four regions on average. The molded densities of the foam in the regions are tested respectively (each region tested 3 times for the average value). Among the molded densities of the four regions, the difference between the maximum density and the minimum density is lower than 10% of the average molding density p, which means that the foam density in each potting region is uniform, and there will be no subsequent foam shrinkage in the cells.

[0204] Example 13

[0205] (1) 128 cells were placed in the casing of the battery module 1 with the gaps between the cells having a spacing 1 of 1.5mm,

[0206] (2) A silicone foam board with a thickness of 1cm having four through-holes was used to cover all cells, (3) By using the potting device for a battery module described in Example 5, potting materials Component A and Component B according to Table 1 were transferred from the raw material tank A and the raw material tank B to the mixing and discharging device for the potting material A-LAB 10H (in Example 4) and HK270 (in Example 5) via a pump 150. The raw materials were mixed in the mixing and discharging device for the potting material and delivered at a flow rate of 110 g / s (A- LAB 10H ) and 200 g / s (HK270) to the shunt pouring device. All bendable flexible pipes in the shunt pouring device (in Example 5) were inserted into the four gaps between the cells through the through- holes in the silicone foam plate, i.e., the pouring ports. The mixed potting material was poured into the pouring ports by the shunt pouring device. The pouring height is smaller than the height of the cells. The shunt pouring device was removed, after the pouring was completed. A pressure was applied onto the silicone foam plate so that the silicone foam plate was kept from displacing in the vertical direction z,

[0207] (4) The potting material flowed to all gaps and spaces, was foamed and cured. The silicone foam plate is removed.

[0208] A battery module with good potting effect is also obtained. There are no bubbles and defects between the cells and the potting material. The potting material is uniform in height and is flat on the surface. There is no potting material on the cells. The potted battery module is divided into four regions on average. The molded densities of the foam in the regions are tested respectively (each region tested 3 times for the average value). Among the molded densities of the four regions, the difference between the maximum density and the minimum density is lower than 10% of the average molding density p, which means that the foam density in each potting region is uniform, and there will be no subsequent foam shrinkage in the cells.

[0209] Comparative Example 1

[0210] The potting device for battery module as shown in Fig.1 is used. As shown in Fig.1, the shunt pouring device 100 comprises a main pipe 115 and two branch pipes. Each branch pipe comprises a rigid pipe fitting 120 and a bendable flexible pipe 160 connected with each other. The main pipe is fixedly connected to the branch pipes. The bendable flexible pipes 160 and the rigid branch pipes 120 are self-locking connected. The total lengths of the two branch pipes are the same. The outlet cross- sectional area of the main pipe 115 is 160 mm2. The outlet inner cross-sectional area of the bendable flexible pipes of the branch pipes 160 is 8 mm2. The same potting material and potting method as in Example 10 is used.

[0211] The photo of the battery module obtained after potting is shown in Fig. 13. As shown in Fig. 13, since the total outlet cross-sectional area of the branch pipes is less than 15% of the cross-sectional area of the pouring gun head of the pouring machine, the foam cells of polyurethane potting material after foaming become significantly bigger, the cell size is uneven, and locally, it becomes darker or even blackened, which will cause an uneven distribution of the mechanical strength of the potting material, and affect the application of the battery modules.

[0212] Comparative Example 2

[0213] A potting device for battery module as shown in Fig.l is used. The mixing and discharging device for the potting material 110 is HK270. The shunt pouring device 100 is replaced by the shunt pouring device 800 as shown in Fig. 8a. The bendable flexible pipes 860 are polyester hoses. The outlet cross- sectional area of the bendable flexible pipes 860 is 6 mm2. The outlet cross-sectional area of the main pipe 815 is 90 mm2. The main pipe is fixedly connected to the branch pipes. The clamped connection is applied between the bendable flexible pipes 860 and the rigid pipe fittings 820. The rigid pipe fittings of the branch pipes have the same length. Among the six bendable flexible pipes 860, four have the same length. The length difference between the longest and the shortest bendable flexible pipe is 35% of the length of the shortest bendable flexible pipe. The same potting material and potting method as in Example 9 is used.

[0214] The photo of the battery module obtained after potting is shown in Fig. 14. As shown in Fig. 14, due to the large difference in the length of the branch pipes, the polyurethane potting material is not evenly leveled and does not produce a uniform foaming height within the operable time of the system, and there are voids and defects in the cell regions poured with the foam. The potted battery module is divided into four regions on average. The molded densities of the foam in the regions are tested respectively (each region tested 3 times for the average value). Among the molded densities of the four regions, the difference between the maximum density and the minimum density is lower than 15% of the average molding density p, which means that the foam density in each potting region is uneven, and there will be subsequent foam shrinkage in the cells.

[0215] Although the embodiments of the present invention are described above, those skilled in the art should understand that this is only illustrative. The protection scope of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principle and essence of the present invention if these changes and modifications fall within the protection scope of the present invention.

Claims

Claims:

1. A potting device for battery module comprising a mixing and discharging device for the potting material (110) and further comprising at least a shunt pouring device (100, 200, 300, 400, 500, 600, 700, 800); wherein the mixing and discharging device for the potting material (110) has an outlet with an outlet inner cross-sectional areawherein the shunt pouring device comprises at least one main pipe (115, 215, 315, 415, 515, 615,715, 815) and at least two branch pipes comprising at least one of rigid pipe fitting (120, 220, 320, 420, 520, 620, 720, 820) and bendable flexible pipe (160, 260, 360, 460, 560, 760, 860), each of the branch pipes has an outlet with an outlet inner cross-sectional area Si,,,,,,-!,. and the outlet inner cross-sectional areas Sb^h of the branch pipes are identical or different, wherein the main pipe is connected to each of the branch pipes, and the shunt pouring device is connected to the outlet of the mixing and discharging device for the potting material (110) via the main pipe, wherein the following applies to the sum of the outlet inner cross-sectional areas of all branch pipesand wherein the mixing and discharging device for the potting material (110) is a discharging device with an output flow rate of greater than or equal to 100 g / s.

2. The potting device for battery module according to claim 1, characterized in that the potting device for battery module further comprises a cover plate (190) which is made of a material comprising at least a foam board, preferable a silicone foam board, a polyethylene foam board, a polystyrene foam board, a polyurethane foam board or combinations thereof, covering and contacting the upper surface of the cells; the cover plate has a thickness greater than or equal to 3mm, preferably 3mm-10cm, and more preferably lcm-5cm.

3. The potting device for battery module according to claim 2, characterized in that the polyurethane foam board has a fdm layer arranged on the surface in contact with the cells, the film is preferably one or more of polyhexafluoropropylene, polytetrafluoroethylene, polytrifluoroethylene, polytrifluorochloroethylene, polyvinylidene difluoride, polyvinyl fluoride, polyethylene, polypropylene, any mixture thereof and any copolymer thereof, more preferably polyhexafluoropropylene, polytetrafluoroethylene, polytrifluoroethylene, polytrifluorochloroethylene, polyvinylidene difluoride, polyvinyl fluoride, any mixture thereof and any copolymer thereof.

4. The potting device for battery module according to claim 2 or 3, characterized in that the cover plate (190) has at least one through-hole for allowing the potting material and / or the outlet of the branch pipes to pass through the through-holes; the number of through-holes being preferably equal to the number of outlets of the branch pipes.

5. The potting device for battery module according to any one of claims 1 to 4, characterized in that the dimension of the outlet outer cross-section of each of the branch pipes is set so that the potting material can be poured via the outlets of the branch pipes into the gaps formed between the cells, preferably is set so that the outlets of the branch pipes can be inserted into the gaps formed between the cells for pouring the potting material.

6. The potting device for battery module according to any one of claims 1 to 5, characterized in that at least a part of at least one of the branch pipes is a bendable flexible pipe (160, 260, 360, 460, 560, 760, 860), preferably, the part of at least one of the branch pipes comprising the outlet is a bendable flexible pipe; more preferably, the branch pipes include a rigid pipe fitting (120, 220, 320, 420, 520, 720, 720’, 820) and the bendable flexible pipe, wherein the rigid pipe fitting is connected to the main pipe.

7. The potting device for battery module according to any one of claims 1 to 6, characterized in that the length difference among all branch pipes is less than or equal to 30%, based on the length of the shortest one among all branch pipes.

8. The potting device for battery module according to any one of claims 1 to 7, characterized in that the number of the branch pipes is an even number of 2 or more, and the branch pipes are preferably distributed in an axisymmetric manner around the main pipe with the central line of the main pipe as the axis; or the number of the branch pipes is an odd number of 3 or more, and the branch pipes are preferably evenly distributed radially with the central line of the main pipe as the axis.

9. The potting device for battery module according to any one of claims 1 to 8, characterized in that the branch pipes are shaped as a straight tubular structure, a bended tubular structure or a semi-n shaped structure, and the bended tubular structure is preferably a right-angled bended tubular structure.

10. The potting device for battery module according to any one of claims 1 to 9, characterized in that the main pipe (515) and / or at least one of the branch pipe are provided with at least one intake pipe(570) for introducing high-pressure gas into the shunt pouring device, and the intake pipe is preferably further provided with at least one valve.

11. The potting device for battery module according to any one of claims 1 to 10, characterized in that the potting device for battery module further comprises at least one raw material tank, which is connected to the mixing and discharging device for the potting material, and a pump is preferably arranged respectively between each raw material tank and the mixing and discharging device for the potting material.

12. A method for potting a battery module, wherein(i) a casing and a number of number of cells arranged in the casing with gaps and spaces between them is provided,(ii) a potting material is poured into a part of the gaps between the cells and / or a part of the spaces between the cells and the casing of the battery module by using the potting device for battery module according to any one of claims 1-11, and the poured potting material flows to all the residual gaps and spaces, and(iii) the potting material is foamed and cured, wherein preferably, the number of the outlets of the branch pipes of the potting device for a battery module is equal to the number of gaps and spaces where the potting material is poured into; a position where the potting material is poured with the branch pipe is the pouring point.

13. The method for potting a battery module according to claim 12, wherein in step (ii), the cells are covered on their upper surfaces with at least one cover plate according to claim 2 or 3 having at least one through-hole located above a gap or space, and the lower surface of the cover plate is the surface which is in contact with the cells, and a potting material is poured through the through-holes into a part of the gaps between the cells and / or into a part of the spaces between the cells and the casing of the battery module by using the potting device for a battery module,and preferably, before the curing is completed, the cover plate is kept from displacing in its vertical direction z.

14. The method for potting a battery module according to claim 13, comprising the following steps:(1) placing all the cells in the casing of the battery module, leaving gaps between the cells, and leaving spaces between the cells and the casing;(2) covering the upper surfaces of the cells with at least one cover plate, the cover plate having a number of through-holes equal to the number of outlets of the branch pipes;(3) inserting the outlets of the branch pipes through the through-holes into a part of the gaps and / or a part of the spaces, and then pouring the potting material; or place the outlets of the branch pipes above the through-holes, and then pouring the potting material so that the potting material flows into a part of the gaps and / or a part of the spaces through the through- holes; wherein the potting material is output from the mixing and discharging device at an output flow rate greater than or equal to lOOg / s, preferably 100g / s-250g / s, more preferably 100g / s-200g / s, and is poured into a part of the several gaps and / or a part of the spaces through the outlets of the branch pipes;(4) the poured potting material flows to all the residual gaps and spaces, the poured potting material is foamed and cured, and,(5) preferably, the cover plate is removed; wherein, during the time period from the completion of pouring in step (3) to the completion of curing in step (4), a pressure is constantly applied onto the cover plate, so that the cover plate is kept from displacing in its vertical direction (z) during this time period.

15. The method for potting a battery module according to claim 12, characterized in that it comprises after pouring the potting material, covering at least one cover plate as defined in claims 2 and / or 3 on the upper surface of the cells, and applying a pressure onto the cover plate, so that the cover plate is kept from displacing in its vertical direction before the completion of curing.

16. The method for potting a battery module according to claim 15, characterized in that it comprises the following steps:(1) placing all the cells in the casing of the battery module, leaving gaps between the cells, and leaving spaces between the cells and the casing;(2) inserting the outlets of the branch pipes into a part of the gaps and / or a part of the spaces, and then pouring the potting material; or placing the outlets of the branch pipes above a part of the gaps and / or a part of the spaces, and then pouring the potting material, so that the potting material flows into a part of the gaps and / or a part of the spaces, covering the upper surfaces of the cells with at least one cover plate, the cover plate has no through-holes; wherein, the potting material is output from the mixing and discharging device at an output flow rate greater than or equal to lOOg / s, preferably 100g / s-250g / s, more preferably lOOg / s- 200g / s, and poured through the outlets of the branch pipes into a part of the gaps and / or a part of the spaces;(3) the poured potting material flows into all the residual gaps and spaces, the potting material is foamed and cured; and(4) preferably, the cover plate is removed; wherein, during the time period from the completion of the pouring in step (2) to the completion of the curing in step (3), a pressure is continuously applied onto the cover plate, so that the cover plate is kept from displacing in its vertical direction z during this time period.

17. The method for potting a battery module according to claim 15, characterized in that one pouring point is set for every 10-50 cells, and more preferably one pouring point is set for every 20-40 cells.

18. The method for potting a battery module according to any one of claims 12 to 17, characterized in that a high-pressure gas is introduced into the intake pipe(570) after the pouring is completed, wherein the high-pressure gas has a pressure of 2-20 bar, preferably 8-15 bar, and a gas flow rate of 5-50 Nm3 / h, preferably 30-50 Nm3 / h.

19. A battery module comprising a casing and a number of cells arranged in the casing, wherein a cured potting material obtained by the method for potting a battery module according to any one ofclaims 12 to 18 is present between the cells and between the cells and the casing, and wherein the height of the cured potting material is preferably less than or equal to the height of the cells; the number of the cells is preferably 10-1000, more preferably 10-900; and the distance between adjacent cells is preferably 0.5-10 mm, more preferably 0.5-5 mm;20. An electric vehicle, characterized in that it comprises at least one battery module according to claim 19.

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