Battery cell

Abstract

A battery cell (100) is provided with a plurality of cooling members (10) and a plurality of battery cells (20). Each cooling member (10) includes a first member (11) and a second member (12). The first member (11) and the second member (12) are each formed of a metal plate. The second member (12) forms, together with the first member (11), a space (13) into which a cooling liquid is supplied. Each of the single batteries (20) takes a metal can (21) as a housing member. The single battery (20) is disposed between the space (13) of one cooling member (10) and the space (13) of the other cooling member (10). Each of the single cells (20) is bonded to the first member (11) or the second member (12) of at least one of the one cooling member (10) and the other cooling member (10).

Description

Technical Field

[0001] This disclosure relates to battery cells. Background Technology

[0002] For example, electric vehicles are equipped with battery cells that consist of multiple individual battery cells. In electric vehicles, large-capacity battery cells are used to ensure the range of operation (driving range) on electric power alone.

[0003] For battery cells, cooling is required to ensure stable operation of individual cells at appropriate temperatures. For example, Patent Document 1 discloses a technique for arranging a row of pouch cells between a pair of cooling plates. In Patent Document 1, each cooling plate is constructed of two metal plates having internal cavities. A heat transfer fluid is supplied to the cavities of each cooling plate. Patent Document 1 describes how, due to the thermal contact between the individual cells and the cooling plates, heat exchange occurs between the individual cells and the heat transfer fluid, resulting in a decrease in the temperature of the individual cells.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent No. 6125624 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] For example, in the case of electric vehicles equipped with battery cells, the battery cells are also required to protect the individual cells in the event of a collision (crash resistance). To ensure crash resistance, a frame structure is usually installed on the battery tray that houses the individual cells. However, in typical battery cells, the components used to ensure crash resistance are separate from the components used to ensure cooling. Therefore, in battery cells, this sometimes results in an increase in the number of components and a more complex structure.

[0009] The subject of this disclosure is to provide a battery cell that has both cooling performance and impact resistance.

[0010] Methods for solving problems

[0011] The battery cell disclosed herein includes multiple cooling components and multiple individual cells. Each of the multiple cooling components includes a first component, a second component, an inlet, and an outlet. The first component is formed of a metal plate. The second component is formed of a metal plate. The second component and the first component are joined to each other at their outer periphery, and together with the first component, form a space for supplying coolant. The inlet is used to introduce coolant into the space. The outlet is used to discharge coolant from the space. Each of the multiple individual cells uses a metal can as its outer casing. The multiple individual cells are disposed between the space of one cooling component and the space of another cooling component. The multiple individual cells are respectively bonded to the first component or the second component of one cooling component and the other cooling component.

[0012] Invention Effects

[0013] According to this disclosure, it is possible to impart both cooling performance and impact resistance to components within a battery cell. Attached Figure Description

[0014] Figure 1 This is a perspective view of the battery cell in the implementation method.

[0015] Figure 2 It means Figure 1 A partial cross-sectional view of the battery cell shown.

[0016] Figure 3 yes Figure 1 A side view of the cooling components included in the battery cell shown.

[0017] Figure 4 yes Figure 1 Another side view of the cooling components included in the battery cell shown.

[0018] Figure 5 It means Figure 1 A partial 3D view of the battery cell shown.

[0019] Figure 6 yes Figure 1 A cross-sectional view of the cooling components included in the battery cell shown.

[0020] Figure 7 yes Figure 1 Another cross-sectional view of the cooling components included in the battery cell shown.

[0021] Figure 8 This is a diagram showing the deformation behavior of the battery cell in the comparative example.

[0022] Figure 9 This is a diagram illustrating the modified behavior of the battery cell in the embodiment.

[0023] Figure 10The load-displacement curve is obtained through analysis. Detailed Implementation

[0024] The battery cell of this embodiment includes multiple cooling components and multiple individual cells. Each of the multiple cooling components includes a first component, a second component, an inlet, and an outlet. The first component is formed of a metal plate. The second component is formed of a metal plate. The second component and the first component are joined to each other at their outer periphery, and together with the first component, form a space for supplying coolant. The inlet is used to introduce coolant into the space. The outlet is used to discharge coolant from the space. Each of the multiple individual cells uses a metal can as its outer casing. The multiple individual cells are arranged between the space of one cooling component and the space of another cooling component. The multiple individual cells are respectively bonded to the first component or the second component of one cooling component and the other cooling component (first embodiment).

[0025] The battery cell of the first embodiment includes multiple cooling components and multiple individual cells disposed between adjacent cooling components. Each individual cell is bonded to at least one of the adjacent cooling components at a location where the coolant is supplied. Specifically, each individual cell is bonded to either the first or second cooling component. Therefore, an air layer serving as a heat insulation layer is less likely to exist between the individual cell and the first or second cooling component. Consequently, good heat transfer can be achieved between the cooling components, which supply coolant between the first and second components, and the individual cells, thus cooling the individual cells.

[0026] In the battery cell of the first embodiment, each individual cell uses a metal can as its outer casing. That is, unlike pouch cells, the individual cells are not flexible but possess greater rigidity. Therefore, each individual cell can be reinforced by being bonded to at least one cooling member. Consequently, when an impact load is applied to the battery cell, the cooling member is less likely to deform, and the individual cells bonded to the cooling member are less likely to be damaged.

[0027] Thus, according to the first scheme, the cooling components within the battery cell can be endowed with both cooling performance and impact resistance.

[0028] In the battery cell of the first embodiment, the two ends of each of the multiple cooling components in the length direction may protrude outward relative to the multiple individual cells (the second embodiment).

[0029] In the second embodiment, compared to the individual cells disposed between the cooling members, both ends of the cooling members protrude outwards along their length. In this case, when an impact load is input from either end of the cooling member, the end of the cooling member can preferentially deform to absorb the impact energy. Therefore, deformation of the cooling member at the location of the individual cells is less likely to occur, and damage to the individual cells is more easily prevented.

[0030] In the battery cell of the first or second embodiment, it is preferable that, in each of the plurality of cooling components, the area of ​​the cross-section of the first component and the second component at both ends of the length direction of the cooling component perpendicular to the length direction is equal to the area of ​​the cross-section of the first component and the second component at the location in space perpendicular to the length direction (third embodiment).

[0031] In the third scheme, the cross-sectional areas (areas of the sections perpendicular to the length direction of the cooling member) of the first and second components are equal to the cross-sectional areas of the first and second components at the locations where the coolant space is located. By ensuring the cross-sectional areas of the first and second components at both ends along the length direction of each cooling member, when an impact load is input from either end of the cooling member, the first and second components can withstand the impact load with a relatively large area. Therefore, local deformation of the cooling member is less likely to occur, and the individual cells bonded to the cooling member are more easily protected.

[0032] In any of the battery cells in the first to third schemes, the inlet is formed at one end of the length direction of the cooling member and the outlet is formed at the other end of the length direction in each of the multiple cooling members (the fourth scheme).

[0033] In any of the battery cells in schemes 1 to 4, the first component and the second component may be formed from aluminum-plated steel sheets (scheme 5).

[0034] In the cooling component, coolant is supplied to the space formed by the first component and the second component. Therefore, the first component and the second component preferably have corrosion resistance relative to the coolant. Thus, in the fifth embodiment, the first component and the second component are each formed of aluminum-plated steel sheet. As a result, the first component and the second component can have high corrosion resistance relative to the coolant.

[0035] In any of the battery cells in embodiments 1 to 4, the first component and the second component may each be formed of zinc-plated steel sheet. In this case, it is preferable to form a chemical conversion treatment coating on the surface of the zinc-plated steel sheet (e.g., embodiment 6).

[0036] In the sixth embodiment, the first and second components are each formed from zinc-plated steel sheets with a chemically converted coating on their surfaces. This allows the first and second components to exhibit high corrosion resistance relative to the coolant.

[0037] In any of the battery cells in schemes 1 to 6, the first component and the second component can have a Vickers hardness of more than 130 HV (scheme 7).

[0038] In Option 7, the Vickers hardness of components 1 and 2 is above 130 HV. This further improves the impact resistance of the cooling components.

[0039] The following is a reference to the appendix. Figure 1 The embodiments of this disclosure will be described below. In these figures, the same or equivalent structures are labeled with the same reference numerals, and the same descriptions are not repeated.

[0040] [Structure of a battery cell]

[0041] Figure 1 This is a perspective view of the battery cell 100 according to this embodiment. The battery cell 100 is, for example, mounted on an electric vehicle.

[0042] Reference Figure 1 The battery unit 100 includes multiple cooling components 10, multiple individual cells 20, a battery tray 30, and multiple mounting components 40.

[0043] Cooling members 10 are components used to cool individual battery cells 20. Each cooling member 10 is elongated. When the battery cell 100 is mounted in an electric vehicle, the cooling members 10 extend, for example, along the left-right direction or the front-back direction of the vehicle body. Figure 1 In the example shown, the cooling components 10 are arranged in substantially parallel.

[0044] Individual cell 20s are disposed between cooling members 10. More specifically, between two adjacent cooling members 10, the individual cells 20 are arranged in one or two rows along the length of the cooling member 10. Figure 1 In the example, two rows of individual cells 20 are provided between two adjacent cooling components 10.

[0045] The battery tray 30, for example, has a concave shape. Although not shown in the diagram, a cover may also be installed on the battery tray 30. The cooling member 10 and the individual battery cell 20 are housed within the battery tray 30. The cooling member 10 and the individual battery cell 20 are mounted to the base plate of the battery tray 30, for example, by means of a mounting member 40. When the battery unit 100 is mounted in an electric vehicle, the mounting member 40 extends, for example, along the left-right direction or the front-back direction of the vehicle body. Figure 1In this configuration, the mounting members 40 extend in a manner that intersects with the cooling members 10. The mounting members 40 can also be fastened to the base plate of the battery tray 30.

[0046] Figure 2 This is a cross-sectional view obtained by cutting the battery cell 100 with a plane perpendicular to the length direction of the cooling member 10. Figure 2 The image shows two adjacent cooling components 10 and a single cell 20 disposed between the cooling components 10.

[0047] Reference Figure 2 Each cooling component 10 includes a first component 11 and a second component 12. The first component 11 and the second component 12 are each formed of a metal plate. The first component 11 and the second component 12 are joined together at their outer peripheries to form a space 13 for which coolant is supplied.

[0048] Figure 3 This is a side view of the cooling component 10, a diagram viewed from the side of the first component 11. (Refer to...) Figure 3 The first component 11 includes a top plate 111, a peripheral wall 112, and a flange 113.

[0049] The top plate 111 extends along the length of the cooling member 10. In this embodiment, the top plate 111 has a rounded rectangular shape (elliptical trajectory shape) when viewed from the side of the cooling member 10. However, the top plate 111 may also have other shapes, such as a rectangular shape, when viewed from the side of the cooling member 10. A flange 113 is provided on the first member 11 such that it surrounds the top plate 111 when viewed from the side of the cooling member 10. The flange 113 forms the outer periphery of the first member 11. A peripheral wall 112 connects the top plate 111 to the flange 113 throughout the entire circumference of the top plate 111.

[0050] The first component 11 includes an inlet 114 and an outlet 115. The inlet 114 is used to introduce coolant into the space 13 ( Figure 2 The outlet 115 is a hole for draining coolant from the space 13. The coolant used is, for example, an aqueous solution of a long-lasting coolant (LLC) containing organic components.

[0051] In this embodiment, an inlet 114 and an outlet 115 are formed on the top plate 111. The inlet 114 and the outlet 115 are through holes that penetrate the top plate 111 in its thickness direction. The inlet 114 is formed at one end of the top plate 111 in the longitudinal direction of the cooling member 10. The outlet 115 is formed at the other end of the top plate 111 in the longitudinal direction of the cooling member 10.

[0052] Figure 4 This is a side view of the cooling component 10, a diagram viewed from the side of the second component 12. (Refer to...) Figure 4 The second component 12 includes a top plate 121, a peripheral wall 122, and a flange 123.

[0053] The top plate 121 extends along the length of the cooling member 10. The top plate 121 preferably has a connection with the top plate 111 of the first member 11. Figure 3 The top plate 121, similar to the top plate 111 of the first member 11, has a rounded rectangular shape (elliptical trajectory shape) when viewed from the side of the cooling member 10. A flange 123 is provided on the second member 12 such that it surrounds the top plate 121 when viewed from the side of the cooling member 10. The flange 123 forms the outer periphery of the second member 12. A peripheral wall 122 connects the top plate 121 to the flange 123 throughout the entire circumference of the top plate 121.

[0054] The second component 12 includes an inlet 124 and an outlet 125. The inlet 124 is used to introduce coolant into the space 13 ( Figure 2 The outlet 125 is a hole for draining coolant from the space 13.

[0055] In this embodiment, an inlet 124 and an outlet 125 are formed on the top plate 121. The inlet 124 and outlet 125 are through holes that penetrate the top plate 121 in its thickness direction. The inlet 124 is formed at one end of the top plate 121 in the longitudinal direction of the cooling member 10. The outlet 125 is formed at the other end of the top plate 121 in the longitudinal direction of the cooling member 10. The inlet 124 and outlet 125 are respectively disposed at the inlet 114 and outlet 115 of the first member 11. Figure 3 The corresponding position.

[0056] return Figure 2 The first member 11 and the second member 12 together form a closed section. The top plate 111 of the first member 11 and the top plate 121 of the second member 12 are opposed to each other with a gap. In this embodiment, the top plates 111 and 121 are each flat and are arranged substantially parallel to each other. The top plate 111 and peripheral wall 112 of the first member 11 and the top plate 121 and peripheral wall 122 of the second member 12 together define a space 13 for coolant. The flange 113 of the first member 11 engages with the flange 123 of the second member 12 around the space 13.

[0057] Flanges 113 and 123 are joined in a liquid-tight manner. A sealant 14 can also be used for the joining of flanges 113 and 123. The sealant 14 is, for example, a coating agent with resin as its main component. As the sealant 14, sealants known as sealants for ensuring liquid tightness can be used. Flanges 113 and 123 can also be joined using the sealant 14 and spot welding or mechanical joining. Examples of mechanical joining include joining flanges 113 and 123 based on localized riveting, joining using rivets, etc. Alternatively, flanges 113 and 123 can also be joined by continuous welding such as laser welding, seam welding, brazing, or friction diffusion joining. Flanges 113 and 123 can also be joined using an adhesive. When the sealant 14 functions as an adhesive, flanges 113 and 123 can be joined using only the sealant 14.

[0058] exist Figure 2 In this example, the second member 12 also includes a flange 126. The flange 126 is continuously disposed with the flange 123. For example, when the battery unit 100 is mounted in an electric vehicle, the flange 126 is adjacent to the flange 123 at the lower end of the cooling member 10 and extends along the length of the cooling member 10. The flange 126 is connected to the mounting member 40, for example, by spot welding. Figure 1 ) join.

[0059] Multiple cooling components 10 are arranged such that the spaces 13 of each cooling component 10 face the spaces 13 of other cooling components 10. The cooling components 10 are arranged side-by-side with other cooling components 10. Multiple individual cells 20 are disposed between the spaces 13 of one cooling component 10 and the spaces 13 of another cooling component 10. The individual cells 20 are respectively bonded to the first component 11 or the second component 12 of at least one of these cooling components 10. That is, the individual cell 20 is bonded to at least one cooling component 10 at the location of the space 13. In this embodiment, rows of individual cells R1 and R2 are arranged between two adjacent cooling components 10. Rows of individual cells R1 and R2 each include two or more individual cells 20 arranged along the length direction of the cooling component 10. The individual cells 20 of row R1 are bonded to the second component 12 of one cooling component 10. The individual cells 20 of row R2 are bonded to the first component 11 of the other cooling component 10.

[0060] Each individual cell 20 is bonded to at least one cooling member 10 via an adhesive layer 50. The adhesive layer 50 is preferably a resin material with high thermal conductivity, for example, having a thermal conductivity of 1.0 W / m or higher. The adhesive layer 50 fills the gaps between the cooling member 10 and the individual cell 20. For example, the adhesive layer 50 fills not only gaps caused by differences in shape between the cooling member 10 and the individual cell 20, but also fine gaps caused by surface roughness of the cooling member 10 and the individual cell 20. The adhesive layer 50 can be formed using known adhesives or sealants.

[0061] The single battery cell 20 is, for example, a lithium-ion battery cell. Each single battery cell 20 has a metal can 21 as its outer casing. Specifically, the single battery cell 20 is a prismatic or cylindrical single battery cell. In this embodiment, the single battery cell 20 is a prismatic single battery cell with a cuboid metal can 21 as its outer casing. Although not shown in the figure, the metal can 21 contains electrodes, electrolyte, etc. The metal can 21 is, for example, formed of an aluminum alloy plate.

[0062] When the individual cell 20 is a square cell, each individual cell 20 is arranged such that at least one side of it faces any one of the cooling members 10. This side of the individual cell 20 is bonded to the cooling member 10. In the example of this embodiment, at least one side of the individual cell 20 faces the top plate 111 of the first member 11 or the top plate 121 of the second member 12, and is bonded to the top plate 111 or the top plate 121 by an adhesive layer 50.

[0063] The thickness W2 of the single cell 20 is preferably greater than or equal to the thickness W1 of the cooling member 10. The thickness W2 of the single cell 20 is, for example, 18.0 mm or more and 80.0 mm or less. The thickness W1 of the cooling member 10 is, for example, 2.0 mm or more and 10.0 mm or less. When the single cell 20 is a prismatic cell, the thickness W2 of the single cell 20 is the straight-line distance between the side facing the cooling member 10 and the side opposite to it. On the other hand, when the single cell 20 is a cylindrical cell, the thickness W2 of the single cell 20 is its diameter. The thickness W1 of the cooling member 10 is the maximum thickness of the cooling member 10 at the location where the space 13 is located. In the example of this embodiment, the thickness W1 of the cooling member 10 is the distance in the cross-section of the battery cell 100 from the top plate 111 of the first member 11 to the top plate 121 of the second member 12 in the thickness direction of the top plates 111 and 121. The thickness W3 of the adhesive layer 50, that is, the distance from the single cell 20 to the cooling member 10 in the thickness direction of the single cell 20, is, for example, 0.1 mm or more and 8.0 mm or less, preferably 0.5 mm or more and 3.0 mm or less.

[0064] Figure 5This is a perspective view showing two adjacent cooling components 10 and a single battery cell 20 disposed between the cooling components 10. (See diagram below.) Figure 5 As shown, in this embodiment, the two ends of each cooling member 10 in the longitudinal direction protrude outward relative to the single cell 20. That is, in the longitudinal direction of the cooling member 10, the length of each cooling member 10 is greater than the length of each of the single cell arrays R1 and R2. At least a portion of the flanges 113 and 123 in the cooling member 10 protrudes from both sides of the single cell 20 in the longitudinal direction.

[0065] exist Figure 5 In this example, on one side of the cooling member 10 along its length, coolant inlets 114 and 124 protrude from the individual cell 20. On the other side of the cooling member 10 along its length, coolant outlets 115 and 125 protrude from the individual cell 20.

[0066] In this embodiment, in each cooling member 10, inlet ports 114 and 124 are provided on the first member 11 and the second member 12, respectively. Additionally, outlet ports 115 and 125 are provided on the first member 11 and the second member 12, respectively. In this case, in adjacent cooling members 10, the inlet port 114 of the first member 11 of one cooling member 10 can be connected to the inlet port 124 of the second member 12 of another cooling member 10 using piping. Thus, when one cooling member 10 is directed to space 13 (… Figure 2 When coolant is supplied to the cooling component 10, the coolant can also flow into the space 13 of another cooling component 10 through piping. Similarly, in adjacent cooling components 10, the outlet 115 of the first component 11 of one cooling component 10 can be connected to the outlet 125 of the second component 12 of another cooling component 10 by piping.

[0067] Figure 6 This is a cross-sectional view (see diagram) obtained by cutting the cooling member 10 at its end along its length direction with a plane perpendicular to that length direction. Figure 6 The diagram shows that the cooling member 10 is positioned in the longitudinal direction of the inlet 114, 124 or outlet 115, 125 (…). Figure 5 The cross-section of the cooling member 10 at the junction of the first member 11 and the second member 12 on the outer side. Figure 7 The figure is a cross-sectional view obtained by cutting the cooling member 10 with a plane perpendicular to the length direction at the location of space 13.

[0068] like Figure 6 and Figure 7As shown, the cross-sectional areas of the first member 11 and the second member 12 at both ends of the cooling member 10 along the length direction, perpendicular to the length direction, are substantially equal to the cross-sectional areas of the first member 11 and the second member 12 at the location of space 13, perpendicular to the length direction. The fact that the cross-sectional area of ​​the first member 11 at both ends of the cooling member 10 is equal to the cross-sectional area of ​​the first member 11 at the location of space 13 means that parts of the first member 11 at both ends of the cooling member 10 have not been intentionally removed. Similarly, the fact that the cross-sectional area of ​​the second member 12 at both ends of the cooling member 10 is equal to the cross-sectional area of ​​the second member 12 at the location of space 13 means that parts of the second member 12 at both ends of the cooling member 10 have not been intentionally removed. Preferably, the first member 11 and the second member 12 have substantially constant cross-sectional areas along the entire length of the cooling member 10. In this embodiment, when the first component 11 and the second component 12 are viewed from the side of the cooling component 10 ( Figure 3 and Figure 4 It is essentially rectangular in shape.

[0069] In the cross-section of the cooling member 10, when the length of the first member 11 in the direction perpendicular to the arrangement direction of the first member 11 and the second member 12 is defined as the height H1 of the first member 11, the height H1 of the first member 11 is substantially the same at both ends of the cooling member 10 in the length direction and at the location of the space 13. In the cross-section of the cooling member 10, when the length of the second member 12 in the direction perpendicular to the arrangement direction of the first member 11 and the second member 12 is defined as the height H2 of the second member 12, the height H2 of the second member 12 is substantially the same at both ends of the cooling member 10 in the length direction and at the location of the space 13.

[0070] [Battery cell material]

[0071] In each of the cooling components 10, the first component 11 and the second component 12 are typically formed from steel plates to ensure their strength. The first component 11 and the second component 12 can be formed, for example, by pressing the steel plate. The thickness of each of the first component 11 and the second component 12 is, for example, 0.4 mm or more and 2.0 mm or less, preferably 0.8 mm or more and 1.4 mm or less. The thickness of the first component 11 is preferably the same as the thickness of the second component 12.

[0072] From the viewpoint of ensuring corrosion resistance relative to the coolant, the first component 11 and the second component 12 can each be formed of aluminum-coated steel sheet. The aluminum-coated steel sheet is a steel sheet comprising a base steel sheet and an aluminum (Al)-based coating formed on the base steel sheet.

[0073] Al-based coatings are coatings containing Al. For example, an Al-based coating contains 70% or more Al by mass%. Al-based coatings are preferably two-component or multi-component coatings containing 70-98% Al and 2-15% Si by mass. From the viewpoint of further improving the processability and corrosion resistance of aluminum-coated steel sheets, the Si content of the Al-based coating is further preferably 3-15% by mass. The Al-based coating is formed at least on the surfaces of the first member 11 and the second member 12 located on the side of space 13. The Al-based coating may also be formed on both surfaces of the first member 11 and / or both surfaces of the second member 12.

[0074] Al-based coatings sometimes contain trace amounts of Fe, Ni, Co, etc., as impurity elements. Mg, Sn, mixed rare earth metals, Sb, Zn, Cr, W, V, Mo, etc., can also be added to Al-based coatings as needed. While not particularly limited, Al-based coatings can be, for example, molten coatings, electroplated coatings, or vapor-deposited coatings formed by methods such as molten flux plating, Sendzimir process, and total radiation process.

[0075] To further improve the corrosion resistance of aluminum-coated steel sheets, a chemical conversion coating can be formed on the surface of the aluminum-coated steel sheets. The chemical conversion coating is formed at least on the surfaces of the first member 11 and the second member 12 located on the side of space 13. The chemical conversion coating can be formed on both sides of the first member 11 and / or both sides of the second member 12.

[0076] Chemical conversion coatings are coatings containing Zr-based, Ti-based, or Si-based components as the main component. That is, the chemical conversion coating contains 50% or more Zr-based, Ti-based, or Si-based components by mass%. Chemical conversion coatings may also contain organic components. For example, the coating described in International Publication No. 2022 / 185840 can be used as a chemical conversion coating suitable for aluminum-plated steel sheets. Chemical conversion coatings can be formed, for example, by applying a Zr-based, Ti-based, or Si-based chemical conversion treatment solution (coating solution) to an aluminum-plated steel sheet using a known method and then baking and drying it.

[0077] The first component 11 and the second component 12 may also be formed from zinc-coated steel sheets instead of aluminum-coated steel sheets. Zinc-coated steel sheets are steel sheets comprising a base steel sheet and a zinc (Zn)-based coating formed on the base steel sheet. The Zn-based coating is a coating containing Zn. The Zn-based coating is formed at least on the surfaces of the first component 11 and the second component 12 located on the side of space 13. The Zn-based coating may also be formed on both surfaces of the first component 11 and / or both surfaces of the second component 12.

[0078] Examples of zinc-coated steel sheets include galvanized steel sheets, zinc-nickel steel sheets, galvanized iron steel sheets, galvanized chromium steel sheets, galvanized aluminum steel sheets, galvanized titanium steel sheets, galvanized magnesium steel sheets, galvanized manganese steel sheets, galvanized aluminum-magnesium steel sheets, and galvanized aluminum-magnesium-silicon steel sheets. In these zinc-based coatings, small amounts of dissimilar metal elements or impurities may be present, such as Co, Mo, W, Ni, Ti, Cr, Al, Mn, Fe, Mg, Pb, Bi, Sb, Sn, Cu, Cd, and As. Inorganic substances such as silicon dioxide, aluminum oxide, and titanium dioxide may also be dispersed within the coating.

[0079] Zn-based coatings can also be used in combination with other coatings. That is, zinc-coated steel sheets can have multi-layer coatings formed by combining Zn-based coatings with coatings such as iron coatings, iron-phosphorus coatings, nickel coatings, or cobalt coatings. Although not particularly limited, methods for forming Zn-based coatings and other coatings include, for example, electroplating, hot-dip galvanizing, vapor deposition, dispersion coating, and vacuum coating.

[0080] A chemical conversion coating is formed on the surface of the zinc-plated steel sheet. The chemical conversion coating is formed on at least the surfaces of the first member 11 and the second member 12 located on the side of space 13. The chemical conversion coating may be formed on both sides of the first member 11 and / or both sides of the second member 12.

[0081] The chemical conversion coating is either an inorganic coating or a resin coating. An inorganic coating is a coating containing Si-based or Zr-based components as the main component. That is, the inorganic coating contains more than 50% Si-based or Zr-based components by mass. Organic components may also be present in the inorganic coating. For zinc-plated steel sheets, for example, the inorganic or resin coatings described in International Publication No. 2022 / 185849 as chemical conversion coatings can be used.

[0082] While not specifically limited, chemical conversion coating can be formed by applying an inorganic or resin-based chemical conversion treatment solution (coating solution) to zinc-plated steel sheet using known methods and then baking and drying it. A preferred combination of zinc-plated steel sheet and chemical conversion coating is, for example, a combination of zinc-aluminum-magnesium steel sheet and an inorganic coating containing Si-based components as the main component. Other preferred combinations include zinc-aluminum steel sheet and resin coating.

[0083] In aluminum-coated steel sheets and zinc-coated steel sheets, there are no particular restrictions on the material of the base steel sheet. The base steel sheet material can be, for example, IF steel with added Ti, Nb, B, etc., Al-K steel, Cr-added steel, stainless steel, high-strength steel, low-carbon steel, medium-carbon steel, high-carbon steel, alloy steel, etc.

[0084] In the cooling member 10, the first member 11 and the second member 12 preferably have a Vickers hardness of 130 HV or higher. More preferably, the first member 11 and the second member 12 have a Vickers hardness of 170 HV or higher, and even more preferably, a Vickers hardness of 230 HV or higher. The Vickers hardness of the first member 11 and the second member 12 is, for example, 500 HV or lower. The Vickers hardness of the first member 11 and the second member 12 can be determined by the Vickers hardness test specified in JIS Z 2244-1:2020. Specifically, firstly, test pieces of suitable size for the Vickers hardness test are obtained from any position of the first member 11 and the second member 12 by laser cutting or the like. Next, each test piece is embedded in resin with its respective cross-section arranged on the surface, and the cross-section is ground. Then, at any point along the thickness direction of the cross section, such as at or near the center of the thickness direction, the Vickers hardness is determined according to JIS Z 2244-1:2020, with a test force of 300 gf (2.9 N). The tensile strength (MPa) of each of the first member 11 and the second member 12 is approximately 3.3 times their Vickers hardness.

[0085] [Effect]

[0086] In the battery cell 100 of this embodiment, each individual battery cell 20 is bonded to at least one cooling member 10 at the location of the space 13 where coolant is supplied. The individual battery cell 20 is bonded to the first member 11 or the second member 12 of the cooling member 10 via an adhesive layer 50. The adhesive layer 50 preferably has high thermal conductivity. For example, the adhesive layer 50 is a resin material having a thermal conductivity of 1.0 W / m or higher. The adhesive layer 50 fills the gap between the individual battery cell 20 and the cooling member 10. Therefore, an air layer is less likely to exist between the individual battery cell 20 and the cooling member 10, resulting in good heat transfer between the cooling member 10 and the individual battery cell 20. Thus, the individual battery cell 20 is cooled by the cooling member 10 supplied with coolant.

[0087] In the battery cell 100 of this embodiment, each individual cell 20 uses a metal can 21 as its outer casing, thus exhibiting higher rigidity compared to pouch cells. Therefore, the individual cell 20 can reinforce the cooling member 10 to which it is bonded. Furthermore, the individual cell 20 using the metal can 21 as its outer casing typically has a greater thickness W2 than a pouch cell, further reinforcing the cooling member 10. By bonding the high-rigidity individual cells 20 to the cooling member 10 and reinforcing the cooling member 10, the cooling member 10 is less prone to deformation when an impact load is applied to the battery cell 100. As a result, the individual cells 20 bonded to the cooling member 10 are less likely to be damaged.

[0088] Thus, according to the battery cell 100 of this embodiment, the cooling member 10 can not only perform the cooling performance of the individual battery cell 20, but also perform the impact resistance performance.

[0089] In the battery cell 100 of this embodiment, a plurality of individual cells 20 are arranged between adjacent cooling members 10. The two ends of each cooling member 10 in the longitudinal direction protrude outward relative to the individual cells 20. In this case, it is easier to protect the individual cells 20. Specifically, when an impact load is applied to the battery cell 100 from any end of the cooling member 10 in the longitudinal direction, the end of the cooling member 10 deforms preferentially over the portion opposite to the individual cell 20. Specifically, the flange 113 of the first member 11 and the flange 123 of the second member 12 deform preferentially under the impact load, absorbing impact energy. Therefore, the portion of the cooling member 10 adjacent to the individual cell 20 is less prone to deformation, and the individual cell 20 is less likely to be damaged.

[0090] In each cooling member 10 of the battery cell 10 of this embodiment, the cross-sectional area of ​​the first member 11 at both ends in the longitudinal direction is equal to the cross-sectional area of ​​the first member 11 at the location of the space 13. Furthermore, in each cooling member 10, the cross-sectional area of ​​the second member 12 at both ends in the longitudinal direction is also equal to the cross-sectional area of ​​the second member 12 at the location of the space 13. That is, at both ends of each cooling member 10, the first member 11 and the second member 12 are not partially cut off, ensuring that the cross-sectional areas of the first member 11 and the second member 12 are large. Therefore, when an impact load is input from any end in the longitudinal direction of the cooling member 10, the first member 11 and the second member 12 can withstand the impact load with a larger area. Therefore, local deformation of the cooling member 10 is less likely to occur, making it easier to protect the individual battery cells 20.

[0091] In the battery cell 100 of this embodiment, the first component 11 and the second component 12 of each cooling component 10 are preferably formed of aluminum-plated steel sheet. Preferably, an Al-based coating is provided integrally on the surface of at least the space 13 side of each of the first component 11 and the second component 12. This suppresses corrosion of the first component 11 and the second component 12 by the coolant. By suppressing corrosion of the first component 11 and the second component 12, it is less likely to cause a decrease in the thermal conductivity of the first component 11 and the second component 12, or the dissolution of components of the first component 11 and the second component 12 into the coolant.

[0092] In the battery cell 100 of this embodiment, the first component 11 and the second component 12 of each cooling component 10 may also be formed of zinc-plated steel sheet. In this case, it is preferable to form a chemical conversion treatment coating on the surface of the zinc-plated steel sheet. Preferably, a Zn-based coating is provided uniformly on at least the surface of the first component 11 and the second component 12 on the space 13 side, and the Zn-based coating is covered by the chemical conversion treatment coating. As a result, corrosion of the first component 11 and the second component 12 by the coolant is easily suppressed. Therefore, it is less likely to cause a decrease in the thermal conductivity of the first component 11 and the second component 12, or the dissolution of components of the first component 11 and the second component 12 into the coolant.

[0093] In the battery cell 100 of this embodiment, the first component 11 and the second component 12 of each cooling component 10 preferably have a Vickers hardness of 130 HV or higher. As a result, the cooling component 10 can exhibit higher impact resistance.

[0094] The embodiments of this disclosure have been described above, but this disclosure is not limited to the above embodiments. Various modifications can be made as long as they do not depart from its spirit.

[0095] In the above embodiment, all cooling members 10 included in the battery cell 100 extend in the same direction. However, it is not necessary for all cooling members 10 to extend in the same direction. For example, when the battery cell 100 is mounted on an electric vehicle, some cooling members 10 may extend in the left-right direction of the vehicle body, while the remaining cooling members 10 may extend in the front-rear direction of the vehicle body. In this case, a plurality of individual battery cells 20 are arranged between adjacent cooling members 10, and each individual battery cell 20 is bonded to a first member 11 or a second member 12 of at least one cooling member 10.

[0096] In the above embodiment, when viewed in cross-section of the battery cell 100, the top plate 111, peripheral wall 112, and flange 113 of the first member 11 have a shape substantially symmetrical to the top plate 121, peripheral wall 122, and flange 123 of the second member 12. However, the first member 11 and the second member 12 do not necessarily need to have a symmetrical shape when viewed in cross-section. The first member 11 and the second member 12 only need to be able to form a space 13 for the coolant. For example, one of the first member 11 and the second member 12 may have a top plate, peripheral wall, and flange as described in the above embodiment, while the other of the first member 11 and the second member 12 may be entirely flat. However, when individual cells 20 are arranged on both sides of the cooling member 10, from the viewpoint of cooling these individual cells 20 as uniformly as possible, the first member 11 and the second member 12 preferably have a symmetrical cross-sectional shape as described in the above embodiment.

[0097] In the above embodiment, in each cooling member 10, the coolant inlet 114, 124 is formed at one end in the longitudinal direction, and the outlet 115, 125 is formed at the other end in the longitudinal direction. However, the positions of the inlet 114, 124 and the outlet 115, 125 are not limited thereto. The positions of the inlet 114, 124 and the outlet 115, 125 can be appropriately changed, for example, according to the shape of the cooling member 10, the positional relationship between the cooling member 10 and the individual battery 20, etc.

[0098] In the above embodiments, in each cooling member 10, the first member 11 is provided with an inlet 114 and an outlet 115, and the second member 12 is also provided with an inlet 124 and an outlet 125. However, it is also possible that at least one of the cooling members 10 has a coolant inlet only in one of the first member 11 and the second member 12. For example, it is also possible that the cooling member 10 located at the far end of the cooling members 10 arranged along the left-right or front-back direction of the vehicle body has a coolant inlet only in one of the first member 11 and the second member 12.

[0099] Similarly, at least one of the cooling components 10 may have a coolant outlet only in one of the first component 11 and the second component 12. For example, the cooling component 10 located at the far end of the cooling components 10 arranged along the left-right or front-back direction of the vehicle body may have a coolant outlet only in one of the first component 11 and the second component 12.

[0100] Example

[0101] The present disclosure will be further described in detail below through embodiments. However, the present disclosure is not limited to the following embodiments.

[0102] To confirm the effectiveness of this disclosure, an analysis was performed using general-purpose structural analysis software (LS-DYNA, manufactured by Ansys). In this analysis, as an example, a rod-shaped impactor was brought into contact with a battery cell, which, like the embodiment described above, includes multiple cooling members 10, multiple square individual cells 20, and multiple mounting members 40, along the length of the cooling member 10 to confirm the deformation of the cooling member 10. Additionally, as a comparative example, the same analysis was performed on a battery cell omitting the square individual cells 20. In both the example and the comparative example, the tensile strength of each cooling member 10 was set to 590 MPa, the plate thickness to 1.0 mm, and the tensile strength of each mounting member 40 was set to 1.5 GPa, and the plate thickness to 1.6 mm.

[0103] Figure 8 This is a diagram showing the deformation behavior of the battery cell in the comparative example. Figure 9This is a diagram illustrating the modified behavior of the battery cell in the embodiment. Figure 10 The load-displacement curve was obtained through analysis. Figure 10 In this context, the loads of the embodiments and comparative examples are standardized using the maximum load of the embodiments.

[0104] like Figure 8 As shown, in the comparative example, there is no single cell 20, and the cooling members 10 are not reinforced by the single cell 20. Therefore, the cooling members 10 become flexed as a whole at and near the impact point of the battery cell. Thus, as... Figure 10 As shown, in the comparative example, the load on the battery cell was reduced overall during the collision.

[0105] On the other hand, such as Figure 9 As shown, in this embodiment, the individual battery 20 is bonded to each cooling member 10, and each cooling member 10 is reinforced by the individual battery 20. Therefore, the portion of the cooling member 10 corresponding to the individual battery 20 is essentially undeformed. Thus, as... Figure 10 As shown, in the embodiment, the load on the battery cell during a collision is significantly higher compared to the comparative example. That is, the battery cell in the embodiment exhibits improved collision resistance compared to the battery cell in the comparative example.

[0106] like Figure 9 As shown, in the embodiment, the ends of each cooling member 10 protrude outward in the longitudinal direction than the individual battery 20, so the ends of each cooling member 10 deform before the individual battery 20 and absorb the impact energy.

[0107] Through this analysis, in addition to the fact that the ends of each cooling component 10 deform before the individual cell 20 to absorb the impact energy, the following effects related to impact resistance were also confirmed: the individual cell 20 is bonded to each cooling component 10, and each cooling component 10 is reinforced by the individual cell 20, thereby significantly increasing the load on the battery cell during the impact.

[0108] Explanation of reference numerals in the attached figures

[0109] 100. Battery cell; 10. Cooling component; 11. First component; 114. Inlet; 115. Outlet; 12. Second component; 124. Inlet; 125. Outlet; 13. Space; 20. Single cell; 21. Metal can.

Claims

1. A battery cell, wherein, The battery cell includes: A plurality of cooling components, each including a first component, a second component, an inlet, and an outlet, wherein the first component is formed of a metal plate, the second component is formed of a metal plate, and the second component is joined to the first component at its outer periphery and together with the first component forms a space for supplying coolant; the inlet is used to introduce the coolant into the space, and the outlet is used to discharge the coolant from the space; and Multiple individual battery cells, each with a metal can as its outer casing. The plurality of individual cells are disposed between the space of one cooling member and the space of another cooling member, and are respectively bonded to the first member or the second member of at least one of the first cooling member and the other cooling member.

2. The battery cell according to claim 1, wherein, The two ends of each of the plurality of cooling components protrude outward relative to the plurality of individual cells along their length.

3. The battery cell according to claim 1, wherein, In each of the plurality of cooling components, the area of ​​the cross-sections of the first component and the second component at both ends of the length direction of the cooling component, which are perpendicular to the length direction, is equal to the area of ​​the cross-sections of the first component and the second component at the location of the space, which are perpendicular to the length direction.

4. The battery cell according to claim 1, wherein, In each of the plurality of cooling components, the inlet is formed at one end of the cooling component along its length, and the outlet is formed at the other end along the length.

5. The battery cell according to claim 1, wherein, The first component and the second component are respectively formed of aluminum-plated steel sheets.

6. The battery cell according to claim 1, wherein, The first component and the second component are respectively formed of zinc-plated steel sheets. A chemical conversion coating is formed on the surface of the zinc-plated steel sheet.

7. The battery cell according to any one of claims 1 to 6, wherein, The first component and the second component have a Vickers hardness of 130 HV or higher.

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