Protective plate for battery cell and resin battery module

Abstract

This protective plate for battery cells is arranged on at least the side surfaces of the battery cells in a battery module having a plurality of battery cells, and is configured from a cured product of a thermosetting resin composition containing: a thermosetting resin; the resin composition comprises at least one of phenolic resin, unsaturated polyester resin, diallyl phthalate resin and epoxy resin; and an inorganic fiber filler. A cured product of the thermosetting resin composition is configured such that the thermal conductivity is 20 W / mK or less and the retention rate of the flexural modulus measured by the following high-temperature exposure test is 75%-100% (inclusive).

Description

Technical Field

[0001] The present invention relates to a protective plate for a battery cell and a resin battery module. Background Art

[0002] Various developments have been made so far regarding battery modules. As one of these technologies, for example, the technology described in Patent Document 1 is known. Patent Document 1 describes a battery module comprising: a unit stack formed by stacking a plurality of battery cells having a positive electrode lead and a negative electrode lead and at least one of a negative electrode lead for sensing and a positive electrode lead for sensing; a bus bar assembly having a plurality of bus bar frames, the plurality of bus bar frames having a plurality of connection bus bars electrically connected to any one of the positive electrode lead and the negative electrode lead, a plurality of sensor bus bars electrically connected to the negative electrode lead for sensing or the positive electrode lead for sensing, and a connection storage portion for mounting the connection bus bars and a sensor storage portion for mounting the sensor bus bars; and a sensor assembly having a circuit substrate electrically connected to the connection bus bar and the sensor bus bar and a sensor frame mounted on the front surface of the bus bar assembly and having a substrate built-in portion for housing the circuit substrate (abstract of Patent Document 1, etc.).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application No. 2020-523766 Summary of the Invention

[0006] Technical problem to be solved by the invention

[0007] As a result of research conducted by the present inventors, it was found that the member disposed on the side surface of the unit described in Patent Document 1 has room for improvement in terms of heat resistance and heat insulation.

[0008] Technical solutions to technical problems

[0009] As a result of further research, the inventors discovered the following and completed the present invention: in a resin battery module, a specified thermosetting resin is used for the protective plate arranged on the side of the battery cell, and the maintenance rate of the flexural elastic modulus measured by a high-temperature exposure test is used as an indicator and appropriately adjusted, thereby improving heat resistance and heat insulation.

[0010] According to one embodiment of the present invention, the following battery cell protection plate and resin battery module are provided.

[0011] 1. A protection plate for a battery cell disposed on at least a side surface of a battery cell in a battery module having a plurality of battery cells, wherein:

[0012] The protective plate is composed of a cured product of a thermosetting resin composition.

[0013] The thermosetting resin composition comprises:

[0014] a thermosetting resin comprising at least one of a phenolic resin, an unsaturated polyester resin, a diallyl phthalate resin, and an epoxy resin; and

[0015] Inorganic fiber fillers,

[0016] The cured product of the thermosetting resin composition has a thermal conductivity of 20 W / m·K or less and a flexural modulus retention rate of 75% or more as measured by the following high-temperature exposure test.

[0017] (High temperature exposure test)

[0018] The thermosetting resin composition was injection molded under the conditions of a curing temperature of 175° C. and a curing time of 60 seconds, thereby obtaining a test plate having a width of 10 mm, a length of 170 mm, and a thickness of 4 mm.

[0019] The obtained test plate was heat-treated at 180° C. for 4 hours.

[0020] Next, the test plate was placed inside a muffle furnace and exposed to a high temperature of 450° C. for 3 minutes in the atmosphere. The test plate was then left outside the furnace and cooled to room temperature.

[0021] Before and after high-temperature exposure, the flexural modulus of the test plate at 25°C was measured in accordance with ISO 178, and the respective values were designated as M1 and M2.

[0022] The measured M1 and M2 were used to calculate the maintenance rate (%) of the flexural modulus according to M2 / M1×100.

[0023] 2. The protective plate as described in 1., wherein:

[0024] The flexural modulus of a cured product of the thermosetting resin composition at 25° C., measured in accordance with ISO 178, is 7 GPa or more and 30 GPa or less.

[0025] 3. The protective plate according to 1. or 2., wherein:

[0026] The dielectric breakdown strength of a cured product of the thermosetting resin composition measured according to the following procedure is 7 MV / m or more and 30 MV / m or less.

[0027] (Measurement procedure of dielectric breakdown strength)

[0028] The thermosetting resin composition was subjected to transfer molding under the conditions of a curing temperature of 175° C. and a curing time of 60 seconds, thereby obtaining Test disc with a thickness of 2 mm.

[0029] The obtained test disk was heat-treated at 180° C. for 4 hours.

[0030] The test plate was treated at 20°C and 65% RH for 90 hours in accordance with JISC 2161 / ASTM D149 / IEC 60455-2-2.

[0031] The short-time method increases the voltage from 0 kV at a constant rate until insulation breakdown occurs within 10 to 20 seconds, and measures the breakdown voltage of the test panel when it is broken down.

[0032] Apply a voltage of 40% of the breakdown voltage found by the short-time method for 20 seconds using the step method. If the test disk does not break down, apply a higher voltage for 20 seconds.

[0033] The highest voltage at which no dielectric breakdown occurred was defined as dielectric breakdown strength (MV / m).

[0034] 4. The protective plate according to any one of 1. to 3., wherein:

[0035] The inorganic fiber filler is a short fiber filler having a weight-average fiber length of 100 μm to 300 μm inclusive and / or a long fiber filler having a weight-average fiber length of 1000 μm to 5000 μm inclusive.

[0036] 5. The protective plate according to any one of 1. to 4., wherein:

[0037] The battery cell is pouch-shaped or square-shaped.

[0038] 6. The protection plate according to any one of 1. to 5., which is a pair of end plates provided at each of both end sides of the plurality of battery cells arranged in one direction.

[0039] 7. The protection plate according to any one of 1. to 6., which is a fire-resistant plate disposed between at least one group of adjacent battery cells among the plurality of battery cells arranged in one direction.

[0040] 8. A battery module comprising:

[0041] a plurality of battery cells having battery cell terminals;

[0042] circuit substrate; and

[0043] a bus bar electrically connected to the battery cell terminals of each of the plurality of battery cells and the circuit substrate,

[0044] The battery module includes the protection plate according to any one of 1. to 7., which is arranged on at least a side surface of the battery cell.

[0045] Effects of the Invention

[0046] According to the present invention, there are provided a battery cell protective plate having excellent heat resistance and heat insulation properties, and a resin battery module including the battery cell protective plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 This is a cross-sectional view schematically showing an example of the configuration of a resin battery module according to this embodiment.

[0048] Figure 2 It is a cross-sectional view schematically showing an example of the configuration of a stacked structure of a plurality of battery cells according to the present embodiment.

[0049] Figure 3 It is a cross-sectional view schematically showing an example of the configuration of the connector with a temperature regulation function according to the present embodiment.

[0050] Figure 4 It is a perspective view schematically showing an example of the configuration of a resin battery module according to this embodiment.

[0051] Figure 5 It is a perspective view schematically showing an example of the configuration of a stacked structure of a plurality of battery cells according to the present embodiment.

[0052] Figure 6 It is a perspective view schematically showing an example of the configuration of the connector with a temperature regulation function according to the present embodiment.

[0053] Figure 7 It is a perspective view schematically showing an example of the configuration of each member according to the present embodiment. DETAILED DESCRIPTION

[0054] Hereinafter, embodiments of the present invention will be described using the accompanying drawings. In addition, in all the accompanying drawings, identical components are denoted by identical reference numerals, and descriptions thereof are omitted as appropriate. Furthermore, the drawings are schematic and do not correspond to actual dimensional ratios.

[0055] The resin battery module and the battery cell protection plate of this embodiment will be described.

[0056] Figure 1 and Figure 4 A cross-sectional view and a perspective view schematically showing an example of a resin battery module (battery module 100 ) according to this embodiment are shown, respectively.

[0057] Figure 1 and Figure 4 The battery module 100 includes a plurality of battery cells 10 , a circuit substrate 20 , a bus bar 31 , a fire-resistant plate 50 , an end plate 60 , and a side plate 70 .

[0058] The battery module 100 of this embodiment includes a circuit board 20 , bus bars 31 electrically connecting the cell terminals of each of the plurality of battery cells 10 and the circuit board 20 , and a protection plate 40 disposed on at least the side surfaces of the battery cells 10 .

[0059] exist Figure 1 and Figure 4 In the battery module 100, at least one of the fire-resistant plate 50 and the pair of end plates 60 is disposed on the side of the battery cell 10 and functions as a protective plate 40 for protecting the cell. This protective plate 40 is made of a cured product of a thermosetting resin composition.

[0060] The cured thermosetting resin composition used for the protective plate 40 has a thermal conductivity of 20 W / m·K or less and a flexural modulus retention rate of 75% or more as measured by the following high-temperature exposure test.

[0061] In this embodiment, the lower limit of the flexural modulus maintenance rate of the cured product of the thermosetting resin composition is, for example, 75% or more, preferably 80% or more, and more preferably 85% or more. This improves the heat resistance and heat insulation properties of the protective plate 40 .

[0062] On the other hand, the upper limit of the maintenance rate of the flexural modulus is not particularly limited, and may be 110% or less, 105% or less, or 99% or less.

[0063] The lower limit of the flexural modulus of the cured product of the thermosetting resin composition at 25° C. measured in accordance with ISO 178 is, for example, 7 GPa or more, preferably 8 GPa or more, and more preferably 9 GPa or more. This can suppress deformation of the cured product.

[0064] On the other hand, the upper limit of the flexural modulus at 25° C. is, for example, 30 GPa or less, preferably 29 GPa or less, and more preferably 28 GPa or less. This can further improve the fluidity.

[0065] The lower limit of the dielectric breakdown strength of the cured product of the thermosetting resin composition measured according to the following procedure is, for example, 7 MV / m or more, preferably 8 MV / m or more, and more preferably 9 MV / m or more. This can improve product reliability.

[0066] The upper limit of the dielectric breakdown strength is, for example, 30 MV / m or less, preferably 29 MV / m or less, and more preferably MV / m or less. This can improve the productivity of the material.

[0067] The present inventors have conducted experiments and obtained the following results. However, the present invention is not limited to the description of these Examples.

[0068] A material mixture containing the components in the amounts shown in Table 1 was kneaded using heating rolls with different rotation speeds, and the material cooled into flakes was pulverized to obtain a granular thermosetting resin composition (molding material).

[0069] The details of the raw material components shown in Table 1 are as follows.

[0070] Phenolic resin: Novolac type phenolic resin A: PR-51305 (manufactured by Sumitomo Bakelite Co., Ltd.)

[0071] Diallyl phthalate resin: DAISO DAP A (manufactured by Osaka Soda Co., Ltd.)

[0072] Unsaturated polyester resin: 8523 (manufactured by UPIKA Co., Ltd., Japan)

[0073] Glass fiber: CS3E479 (manufactured by Nitto Bosei Co., Ltd., weight-average fiber length: 3 mm)

[0074] Inorganic filler: UB-13LA (glass beads A, manufactured by Unitika Co., Ltd., average particle size: 45 μm)

[0075] Flame retardant: Flame retardant 1 is magnesium hydroxide, flame retardant 2 is aluminum hydroxide, flame retardant 3 is zinc borate, and flame retardant 4 is an organic flame retardant

[0076] Others: Contains a curing agent (hexamethylenetetramine was used in Examples 1 to 5, and dicumyl peroxide was used in Examples 6 and 7), calcium stearate, and carbon black.

[0077] Table 1

[0078]

[0079] The thermosetting resin compositions shown in Table 1 were used in Examples 1 to 7, a thermoplastic resin material of polyphenylene sulfide resin was used in Comparative Example 1, and a thermoplastic resin material of polybutylene terephthalate resin was used in Comparative Example 2. The following items were evaluated.

[0080] (High temperature exposure test)

[0081] The thermosetting resin compositions of Examples 1 to 7 were injection molded at a curing temperature of 175°C and a curing time of 60 seconds to produce test plates with a width of 10 mm, a length of 170 mm, and a thickness of 4 mm. These test plates were then heat treated at 180°C for 4 hours.

[0082] Next, the test plate was placed inside a muffle furnace and exposed to a high temperature of 450° C. for 3 minutes in the atmosphere. The test plate was then left outside the furnace and cooled to room temperature.

[0083] Before and after high-temperature exposure, the flexural modulus of the test panels at 25°C was measured in accordance with ISO 178. These values were designated as M1 and M2. Using the measured M1 and M2, the flexural modulus retention (%) was calculated as M2 / M1 × 100. The results are shown in Table 1.

[0084] In addition, regarding the thermoplastic resin materials of Comparative Examples 1 and 2, the test plates melted and deformed due to exposure to high temperatures, and thus the flexural modulus could not be measured.

[0085] (Measurement procedure of dielectric breakdown strength)

[0086] The thermosetting resin compositions of Examples 1 to 7 were subjected to transfer molding at a curing temperature of 175° C. and a curing time of 60 seconds to obtain The test disc having a thickness of 2 mm was heat-treated at 180° C. for 4 hours.

[0087] The test plate was treated at 20° C. and 65% RH for 90 hours in accordance with JISC 2161 / ASTM D149 / IEC 60455-2-2.

[0088] Using the short-time method, the voltage is increased from 0 kV at a constant rate so that insulation breakdown occurs within 10 to 20 seconds, and the breakdown voltage of the test panel is measured when the insulation breakdown occurs.

[0089] Using the step method, apply a voltage of 40% of the breakdown voltage found using the short-time method for 20 seconds. If the test panel does not break down, apply a higher voltage for 20 seconds. The highest voltage at which no breakdown occurs is defined as the dielectric breakdown strength (MV / m).

[0090] In addition, regarding the thermoplastic resin materials of Comparative Examples 1 and 2, since the flexural modulus could not be measured, the dielectric breakdown strength was not measured.

[0091] Furthermore, in the flame combustion test, carbonization occurred in all examples but melting was not observed. When the fiber filler was added to the examples, the carbonization area was further reduced.

[0092] In this embodiment, the battery module 100 having the connector 30 with a temperature regulating function can be used in various applications, for example, in vehicles such as electric vehicles, hybrid vehicles, and electric motorcycles, and in power equipment used in homes and factories.

[0093] Hereinafter, each component of the battery module 100 will be described.

[0094] (Module housing: end plate, side plate)

[0095] The battery module 100 includes a plurality of battery cells 10 housed in a housing space within a module housing. Figure 1 The cell arrangement direction (one direction) shown is an arrangement in which the side surfaces having the largest surface areas among the cell surfaces overlap with each other.

[0096] To minimize space requirements when arranging multiple battery modules 100, the module housing may have a substantially rectangular parallelepiped structure. A substantially rectangular parallelepiped panel assembly may be constructed with at least two of its six sides comprised of multiple panel members. However, one or two of the six sides may be free of the panel members that constitute the module housing.

[0097] Furthermore, each panel member constituting the panel assembly mainly has a plate-like structure, but may have a connection structure for connecting to other members in a part thereof.

[0098] Figure 1 The module housing is assembled from a pair of end plates 60 and a pair of side plates 70 and is a panel assembly having a frame structure.

[0099] Specifically, a pair of end plates 60a, 60b are provided on the side surfaces of the battery cells 10 arranged along the cell arrangement direction. A pair of side plates 70a, 70b are coupled to the pair of end plates 60a, 60b to form an enclosure structure (a plate assembly having a frame structure) that houses the battery cells 10.

[0100] In this specification, in a battery module 100 having a substantially rectangular parallelepiped structure, when the cell arrangement direction of the battery cells 10 is set as the X-axis direction, the remaining two directions are the long side direction of the battery module 100 as the Y-direction and the short side direction as the Z-direction. In this case, the installation surface of the end plate 60 becomes the YZ plane, and the installation surface of the side plate 70 becomes the XZ plane.

[0101] In the present embodiment, at least one, and preferably both, of the pair of end plates 60 a and 60 b are made of a cured product of a thermosetting resin composition.

[0102] In another embodiment, the pair of end plates 60 only needs to include a cured product of the thermosetting resin composition, and may include a material other than the thermosetting resin composition, such as a member composed of a composite material of the cured product and a metal material.

[0103] (fireproof board)

[0104] Figure 2 and Figure 5 A cross-sectional view and a perspective view schematically showing an example of a stacked structure of a plurality of battery cells according to the present embodiment are shown, respectively.

[0105] The overall arrangement of multiple battery cells 10 arranged along the cell arrangement direction within a battery module 100 is referred to as a battery cell assembly 11. In this battery cell assembly 11, a fire-resistant plate 50 is positioned between at least one pair of adjacent battery cells 10. Specifically, each battery cell 10 of the battery cell assembly 11 is housed in one of a plurality of storage spaces defined by the fire-resistant plate 50. By dividing the storage spaces, the fire prevention structure can be enhanced.

[0106] The fire-resistant plate 50 divides the storage space of the battery cell 10 in the YZ direction and can also divide the storage space in the XZ direction by covering at least one of the upper and lower surfaces of the XZ plane of the battery cell 10. In this way, by assembling multiple fire-resistant plates 50, a fire-resistant frame 51 having a storage space for accommodating at least one battery cell 10 can be constructed.

[0107] Specifically, the fire-resistant frame 51 has a structure that surrounds each battery cell 10 or a plurality of battery cells 10. The fire-resistant frame 51 only needs to surround two, three, or four surfaces of the battery cell 10 where no battery cell terminals are formed.

[0108] Figure 2 The fire-resistant frame 51 is composed of fire-resistant boards 50a, 50b, 50c, and 50d, for example. However, the fire-resistant boards 50a, 50b, 50c, and 50d can be composed of individual components that can be assembled, but at least a part of them can be composed of the same component. The fire-resistant frame 51 composed of the same component uses a molding material and is formed by a predetermined molding method to form various structures such as a flexural structure. For example, if Figure 5 1. In the example of (a), the fire-resistant boards 50a, 50b, and 50c can be molded together to form a single molded product showing a U-shaped structure.

[0109] Figure 5In the fireproof frame 51 shown in (a), the fireproof panels 50a, 50b, and 50c are composed of a component A having a U-shaped ("コ"-shaped) structure. In this case, a plurality of fireproof frames 51 can be connected to each other, or a plurality of frames can be connected along the unit arrangement direction. In the structure in which a plurality of fireproof frames 51 are connected, as shown in FIG. Figure 5 As shown in (b), the fire-resistant board 50b located between the adjacent storage spaces can be shared. Figure 2 The connected plurality of fire-resistant frames 51 show a structure that surrounds four surfaces of the YZ plane and the XY plane in the battery cell 10 .

[0110] Furthermore, as another embodiment, two large-area plate-shaped fire-resistant boards 50a and 50c can be arranged opposite each other and separated by a plurality of fire-resistant boards 50b and 50d to form a plurality of storage spaces in the fire-resistant frame 51. Alternatively, the fire-resistant frame 51 may include, in addition to the component A, a plate-shaped component B that can be mounted on the component A, namely, the fire-resistant board 50d.

[0111] The thickness of the fire-resistant board 50 is, for example, 0.1 mm to 3.0 mm, preferably 0.5 mm to 2.5 mm, and more preferably 1.0 mm to 2.0 mm. By setting the thickness within this range, a balance between thin-walled lightness and fire-prevention capability can be achieved.

[0112] The storage space of the fire-resistant frame 51 only needs to accommodate at least one battery cell 10. From the perspective of the balance between space miniaturization and the fire prevention structure, a stacked body of two or more battery cells 10, namely a battery cell assembly 11, can also be accommodated.

[0113] Furthermore, various sensors such as temperature sensors can be provided on the outermost layer of the fire-resistant frame 51 in the direction of cell arrangement. For example, the temperature sensor is connected to the circuit board 20 provided on the surface of the end plate 60b via wiring. This allows temperature management of the battery cells 10 within the fire-resistant frame 50.

[0114] Furthermore, in this embodiment, the fire-resistant board 50 is composed of a cured product of a thermosetting resin composition. Details of the thermosetting resin composition will be described later.

[0115] By forming the fire-resistant plate 50 disposed between the multiple battery cells 10 from a cured thermosetting resin composition, heat resistance can be improved compared to using a thermoplastic resin plate. This can suppress a decrease in thermal rigidity. Furthermore, compared to using a thermoplastic resin plate, the insolubility or infusibility of the plate improves fire prevention.

[0116] On the other hand, compared with the case of using metal plates, it is possible to improve heat insulation and electrical insulation and achieve weight reduction. In a battery pack composed of a plurality of such battery modules 100, a structure excellent in preventing spread of fire can be achieved.

[0117] ((Thermosetting resin composition))

[0118] The thermosetting resin composition is not particularly limited as long as it contains a thermosetting resin. For example, it preferably contains at least one thermosetting resin selected from the group consisting of a phenolic resin, an unsaturated polyester resin, a diallyl phthalate resin, and an epoxy resin. From the perspective of heat resistance, a thermosetting resin composition containing at least a phenolic resin can be used.

[0119] One example of a thermosetting resin composition includes a cured product of a thermosetting resin and an inorganic filler.

[0120] When using a phenolic resin, hexamethylenetetramine can be used as a curing agent. Furthermore, when using unsaturated polyester resins or diallyl phthalate resins, organic peroxides such as dicumyl peroxide can be used as a curing agent. Furthermore, when using an epoxy resin, amine compounds, anhydrous forms, phenolic resins, imidazole compounds, and the like can be used as curing agents.

[0121] The inorganic fiber filler may include at least one of a short fiber filler and a long fiber filler.

[0122] The weight average fiber length of the short fiber filler is set to, for example, 100 μm or more and 300 μm or less.

[0123] The weight average fiber length of the long-fiber filler is set to, for example, 1000 μm or more and 5000 μm or less.

[0124] The weight-average fiber length of the single-fiber reinforcement (B) in the molded article is measured, for example, by the following method.

[0125] First, a sample collected from a molded article whose fiber length is to be measured is ashed at 400°C for 9 hours, and the ashed glass fibers are dispersed in a liquid (e.g., acetone). A portion of the dispersion is transferred to a glass slide, and an image is captured at low magnification using an optical microscope to measure the fiber length. This operation is repeated as needed to measure the length of at least 200 fibers. Based on the fiber length distribution thus obtained, the cumulative weight distribution is calculated from the shortest fibers, and the fiber length equivalent to 50% of the cumulative weight is set as the weight-average fiber length.

[0126] As the fibrous filler for short fiber filler and long fiber filler, for example, glass fiber, wollastonite fiber, carbon fiber, plastic fiber etc. can be used. As plastic fiber, for example, aramid fiber (aromatic polyamide) can be used. And, as fibrous filler, inorganic fiber such as basalt fiber or metal fiber such as stainless steel fiber can also be used. Wherein, from the consideration that can improve the mechanical strength as the molded product and contribute to the lightweight as the molded product, it is preferably selected from glass fiber, wollastonite fiber and carbon fiber.

[0127] The thermosetting resin composition is not limited to inorganic fiber fillers and may also contain fillers other than fibers. As the filler, an inorganic filler or an organic filler can be used. As the inorganic filler, a spherical inorganic filler can be used, for example, glass beads, glass powder, calcium carbonate, silica, aluminum hydroxide, clay, etc.

[0128] The thermosetting resin composition may contain various additives used in general molding materials as needed, such as release agents such as stearic acid, calcium stearate, polyethylene, curing aids such as magnesium oxide, calcium hydroxide, triphenylphosphine, colorants such as carbon black, adhesion enhancers or coupling agents for improving the adhesion between the filler and the thermosetting resin, solvents or flame retardants, etc.

[0129] An example of a thermosetting resin composition comprises, based on 100% by mass of solid content, 10% to 50% by mass of the aforementioned thermosetting resin, 1% to 60% by mass of an inorganic fiber filler, and 1% to 60% by mass of a filler other than the inorganic fiber filler (e.g., a spherical inorganic filler). Furthermore, an example of a thermosetting resin composition may contain, as needed, 0.05% to 15% by mass of a thermosetting resin curing agent, 1% to 30% by mass of a flame retardant, a release agent, or at least one of the following:

[0130] The flexural elasticity retention of a cured product of a thermosetting resin composition can be controlled by appropriately selecting the type, blending amount, and production method of each component. Examples of factors for setting the flexural elasticity retention within a desired numerical range include, but are not limited to, using a predetermined amount / type of thermosetting resin, a predetermined amount / type of inorganic fiber filler, and a predetermined amount of a flame retardant.

[0131] The thermosetting resin composition can be produced by, for example, mixing the raw material components by melt kneading, etc. Specifically, melt kneading can be performed using a kneading device such as a roll, a co-kneader, or a twin-screw extruder alone, or using a combination of a roll and other mixing devices.

[0132] The production method is not limited to the melt-kneading method; various known mixing methods can be employed. For example, a method in which continuous fibers are impregnated with or melted into a thermosetting resin and then cut into desired lengths can be employed. Furthermore, in this method, the thermosetting resin may contain an organic filler and / or an inorganic filler.

[0133] The thermosetting resin composition can be in the form of, for example, granules, powder, tablets, sheets, strips, or pellets.

[0134] A molded product (fire-resistant plate 50 , end plate 60 , or side plate 70 ) can be manufactured by a molding method such as transfer molding, compression molding, or injection molding using a thermosetting resin composition and an appropriate mold.

[0135] (Battery Cell)

[0136] The battery cell 10 is formed of a secondary battery in which a sheet stack composed of one or more positive electrode sheets and one or more negative electrode sheets separated by a separator is housed inside an exterior material.

[0137] The battery cell 10 is a secondary battery having any one of a pouch shape, a square shape, and a cylindrical shape (can shape).

[0138] Prismatic and cylindrical secondary batteries are batteries made by rolling a sheet stack and enclosing it in a quadrangular or cylindrical container (external packaging). Pouch-shaped secondary batteries are batteries made by enclosing the sheet stack in its original state in a pouch (external packaging) without winding it. From the perspective of minimizing the space required for configuration, the battery cell 10 is preferably either pouch-shaped or prismatic.

[0139] Examples of secondary batteries include lithium secondary batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-metal hydride batteries, and nickel-zinc batteries. Among these, secondary batteries containing at least one of lithium and nickel are preferably used. In one example of a lithium secondary battery, the positive electrode may contain a lithium-based oxide, and the negative electrode may contain a carbon material.

[0140] Each of the plurality of battery cells 10 has a battery cell terminal (not shown) including a positive electrode lead and a negative electrode lead.

[0141] The pouch-shaped battery cell 10 has a structure in which a sheet-shaped positive lead (positive tab) and a sheet-shaped negative lead (negative tab) are led outward from the exterior packaging. As an example of the pouch-shaped battery cell 10, a bidirectional lead-out type battery cell can be used, in which the positive and negative leads are led out in opposite directions at one end and the other end in the longitudinal direction of the cell.

[0142] (Bus Bar)

[0143] The bus bar 31 is electrically connected to the battery cell terminals of the plurality of battery cells 10. The battery cell terminals and the bus bar 31 can be electrically connected by a known method, such as welding or crimping to join the battery cell terminals to the bus bar 31.

[0144] Furthermore, to electrically connect the plurality of battery cells 10 in parallel, battery cell terminals of the same polarity are connected to one another, and to electrically connect the plurality of battery cells 10 in series, battery cell terminals of different polarities are connected to one another.

[0145] The bus bar 31 may be made of a highly conductive metal material. Examples of the metal material include copper, aluminum, nickel, gold, and alloys containing two or more of these.

[0146] The bus bar 31 may be formed of a single component or a plurality of components.

[0147] Furthermore, the positive and negative leads in the battery cell 10 can each be made of the same material as the portion of the bus bar 31 to which they are connected. The positive and negative leads can be made of the same material or different materials. For example, in the case of different materials, the positive lead can be made of aluminum and the negative lead can be made of copper.

[0148] The wiring portion of the bus bar 31 is housed in the module case together with the plurality of battery cells 10 . The end portions (terminal portions) of the bus bar 31 are exposed to the outside via the end plates 60 b and are electrically connected to the circuit board 20 .

[0149] (Circuit Board)

[0150] The circuit substrate 20 is electrically connected to the busbars 31 and can be connected to the plurality of battery cells 10 via the busbars 31. The circuit substrate 20 may include circuits (BMS circuits) for detecting or controlling the voltage or current of the plurality of battery cells 10, as well as the temperature of the temperature regulating tubes or the temperature of the temperature regulating medium in the temperature regulating tubes for regulating the temperature of the battery cells 10.

[0151] The circuit board 20 only needs to be provided outside the module housing. Figure 4 The center is provided on the outer surface of the end plate 60a.

[0152] (Connector with temperature control function)

[0153] Figure 3 and Figure 6 A cross-sectional view and a perspective view schematically showing an example of the connector with a temperature regulation function according to the present embodiment are shown, respectively.

[0154] The temperature-regulating connector 30 regulates the temperature of the busbar 31. This temperature-regulating function is not particularly limited, as long as it employs a known temperature-regulating method. Specifically, the temperature-regulating connector 30 not only cools the battery cells 10 to prevent them from becoming excessively hot, but also warms them during cold starts in cold regions (for example, warming the battery cells 10 to above 0°C when the battery module 100 is initially used in an environment as low as -10°C).

[0155] like Figure 3 As shown, the temperature-regulating connector 30 includes a bus bar 31 , a temperature-regulating tube 32 for regulating the temperature of the bus bar 31 , and a resin sealing member 33 including at least a filling portion filled between the bus bar 31 and the temperature-regulating tube 32 .

[0156] The temperature control pipe 32 has a pipe structure that allows a known temperature control medium to pass through the inside.

[0157] The temperature control medium may be, for example, a liquid or gas. The cooling medium may be any medium with a temperature lower than the surface temperature of the battery cell 10, such as cold water or cold air. Furthermore, the heating medium may be any medium with a temperature higher than the ambient temperature, such as warm water or warm air.

[0158] The inlet and outlet of the temperature control pipe 32 are exposed to the outside of the module housing, and the temperature control medium can be supplied from the outside and discharged to the outside.

[0159] The temperature control tube 32 can be formed of a material having high thermal conductivity. However, from the viewpoint of workability, the temperature control tube 32 may be formed of a metal material including one or more metal materials. For example, aluminum or an aluminum alloy may be used.

[0160] The bus bar 31 in the connector 30 with a temperature control function may have a structure that follows the surface shape of the temperature control tube 32 or may have a structure that follows the surface shape of the temperature control tube 32. Figure 3 The cross-sectional structure shown in FIG. The cross-sectional shape of bus bar 31 is not limited to a roughly U-shaped structure and may also have a flexural structure including bending and / or bending. This allows for efficient temperature control of bus bar 31.

[0161] like Figure 3 As shown, the resin sealing member 33 is filled in the gap between the bus bar 31 and the temperature regulating tube 32. This improves the thermal conductivity of the gap compared to air, thereby improving the temperature regulating capability of the temperature regulating tube 32.

[0162] Furthermore, the insulation between the bus bar 31 and the temperature regulating tube 32 can be improved, and conduction of the current of the bus bar 31 to the temperature regulating tube 32 can be suppressed.

[0163] The resin sealing member 33 may be formed of a cured epoxy resin composition or a known material. By forming the resin sealing member 33 from a cured epoxy resin composition, it is possible to realize the resin sealing member 33 having excellent heat dissipation and insulation properties.

[0164] Here, Figure 6 (a) is from Figure 3 (a) is a perspective cross-sectional view of the connector 30 with a temperature control function as viewed from the side plate 70a side. Figure 6 (b) is a perspective view of the connector 30 with a temperature control function viewed from the battery unit 10 side.

[0165] like Figure 6 (a) Figure 6 As shown in (b), the resin sealing member 33 may include a bus bar covering portion that covers the surface of the bus bar 31 other than the surface bonded to the lead electrode (the surface adjacent to the battery cell 10), or a temperature regulating tube covering portion that covers the periphery of the temperature regulating tube 32. In this way, the resin sealing member 33 realizes a structure in which the bus bar 31 and the temperature regulating tube 32 are formed as an integral component.

[0166] If necessary, the connector 30 with a temperature control function may include an insulating covering member between the bus bar 31 and the temperature control tube 32 , covering at least a portion or the entire surface of the temperature control tube 32 .

[0167] As the insulating covering member, a known material can be used, for example, insulating paper can be used.

[0168] In addition, the insulating covering member is embedded in the resin sealing member 33. This further improves the insulating properties of the resin sealing member 33.

[0169] In another way, Figure 6 As shown in (c) of FIG. 1 , at least one of the pair of side plates (the side plate 70 a ) can function as a cover plate that covers at least a portion of the connector 30 with a temperature control function.

[0170] In another embodiment, the battery module 100 may include a fire-resistant rupture valve plate 80 disposed between the thermostat connector 30 and the cover plate (side plate 70a). The fire-resistant rupture valve plate 80 creates a gas discharge path and prevents gas accumulation within the battery module 100, which could cause an explosion. For example, an air circulation path may be created between the side plate 70a and the fire-resistant rupture valve plate 80. The inlet and outlet of the air circulation path may be formed by holes in the end plate 60.

[0171] Furthermore, in another embodiment, at least one of the side plate 70a (including the case where it functions as a cover plate), the side plate 70b and the fire-resistant rupture valve plate 80 can be made of a known material, but from the perspective of the ability to prevent fire spread, it can also be mainly composed of a component including a cured product of a thermosetting resin composition.

[0172] in addition, Figure 7 1 shows an example of each member constituting the battery module 100 .

[0173] While the embodiments of the present invention have been described above, these are merely examples of the present invention, and various configurations other than those described above can be employed. Furthermore, the present invention is not limited to the above embodiments, and modifications and improvements within the scope of achieving the objectives of the present invention are included within the present invention.

[0174] This application claims the benefit of priority based on Japanese patent application No. 2022-212337, filed on December 28, 2022, and incorporates herein the entire disclosure of that application.

[0175] Explanation of symbols

[0176] 100: Battery module; 10, 10a, 10b, 10c, 10d: Battery cell; 11: Battery cell assembly; 20: Circuit board; 30: Connector with temperature control function; 31: Bus bar; 32: Temperature control tube; 33: Resin sealing component; 40: Protective plate; 50, 50a, 50b, 50c, 50d: Fire-resistant board; 51: Fire-resistant frame; 60, 60a, 60b: End plate; 70, 70a, 70b: Side plate; 80: Fire-resistant rupture valve plate.

Claims

1. A protection plate for a battery cell disposed on at least a side surface of a battery cell in a battery module having a plurality of battery cells, characterized in that: The protective plate is composed of a cured product of a thermosetting resin composition. The thermosetting resin composition comprises: a thermosetting resin comprising at least one of a phenolic resin, an unsaturated polyester resin, a diallyl phthalate resin, and an epoxy resin; and Inorganic fiber fillers, The cured product of the thermosetting resin composition has a thermal conductivity of 20 W / m·K or less and a flexural modulus retention rate of 75% or more as measured by the following high-temperature exposure test. In the high temperature exposure test, The thermosetting resin composition was injection molded under the conditions of a curing temperature of 175° C. and a curing time of 60 seconds to obtain a test plate having a width of 10 mm, a length of 170 mm, and a thickness of 4 mm. The obtained test plate was heated at 180°C for 4 hours. Next, the test plate was placed inside a muffle furnace and exposed to a high temperature of 450° C. for 3 minutes in the atmosphere. The test plate was then placed outside the furnace and cooled to room temperature. Before and after high temperature exposure, the flexural modulus of the test plate at 25°C was measured in accordance with ISO178, and the values were set as M1 and M2. The measured M1 and M2 were used to calculate the maintenance rate (%) of the flexural modulus according to M2 / M1×100.

2. The protective plate according to claim 1, wherein: The flexural modulus of a cured product of the thermosetting resin composition at 25° C., measured in accordance with ISO 178, is 7 GPa or more and 30 GPa or less.

3. The protective plate according to claim 1 or 2, wherein: The dielectric breakdown strength of the cured product of the thermosetting resin composition measured according to the following procedure is 7 MV / m or more and 30 MV / m or less. In the determination step of dielectric breakdown strength, The thermosetting resin composition was subjected to transfer molding under the conditions of a curing temperature of 175° C. and a curing time of 60 seconds, thereby obtaining a test disk having a diameter of 100 mm and a thickness of 2 mm. The obtained test disk was heated at 180°C for 4 hours. According to JISC 2161 / ASTMD149 / IEC 60455-2-2, the test plate was treated at 20°C, 65% RH, for 90 hours. By using the short-time method, the voltage is increased from 0kV at a certain speed so that insulation breakdown occurs in 10 to 20 seconds, and the breakdown voltage of the test plate is measured when it is broken down. By the step method, apply 40% of the breakdown voltage obtained by the short time method for 20 seconds. If the test plate is not broken down, apply a higher voltage for 20 seconds. The highest voltage at which no dielectric breakdown occurred was defined as dielectric breakdown strength (MV / m).

4. The protective plate according to any one of claims 1 to 3, characterized in that: The inorganic fiber filler comprises: a short fiber filler having a weight-average fiber length of 100 μm or more and 300 μm or less; and / or A long-fiber filler having a weight-average fiber length of 1000 μm or more and 5000 μm or less.

5. The protective plate according to any one of claims 1 to 4, characterized in that: The battery cell is pouch-shaped or square-shaped.

6. The protective plate according to any one of claims 1 to 5, characterized in that: The end plates are provided as a pair at each of both end sides of the plurality of battery cells arranged in one direction.

7. The protective plate according to any one of claims 1 to 6, characterized in that: The fire-resistant plate is disposed between at least one group of adjacent battery cells among the plurality of battery cells arranged in one direction.

8. A battery module, characterized in that: have: a plurality of battery cells having battery cell terminals; Circuit board; and a bus bar electrically connected to the battery cell terminals of each of the plurality of battery cells and the circuit substrate, The battery module includes the protection plate according to any one of claims 1 to 7, which is arranged on at least a side surface of the battery cell.

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