battery pack

Abstract

The present invention relates to a battery pack (100) comprising: a plurality of stacked single cells (11); a holding member (21) for holding the plurality of single cells (11); an adhesive member (51) sandwiched between the single cells (11) and the holding member (21) for bonding the single cells (11) to the holding member (21); and a thermally conductive member (41) having a smaller elastic modulus than the adhesive member (51) sandwiched between the single cells (11) and the holding member (21).

Description

Technical Field

[0001] This invention relates to battery packs. Background Technology

[0002] For example, U.S. Patent No. 1,100,5131 discloses a battery box having a housing, a plurality of individual cells housed in the housing, and a thermally conductive adhesive filled between the bottom of the housing and the plurality of individual cells.

[0003] In addition, Japanese Patent Application Publication No. 2016-15328 discloses an energy storage device comprising a housing, a power generation element disposed within the housing, a cooling component disposed on the lower surface of the housing and forming a flow path for refrigerant to flow through, and a heat-conducting component disposed between the cooling component and the housing and made of a material with higher thermal conductivity than air.

[0004] In addition, Japanese Patent Application Publication No. 2014-60088 discloses a secondary battery device as follows: comprising a housing having a battery storage chamber, a single battery stored in the battery storage chamber, and an adhesive for bonding and fixing the single battery to the inner surface of the housing.

[0005] As disclosed in the aforementioned patent documents, battery packs are known to include multiple individual cells and holding components such as housings for holding the multiple individual cells. In such battery packs, it is required to balance reliable fixation of the individual cells relative to the holding components and efficient cooling of the individual cells as heat-generating elements. Summary of the Invention

[0006] Therefore, the object of the present invention is to solve the above-mentioned problems and provide a battery pack that can achieve both reliable fixation of individual cells and efficient cooling of individual cells.

[0007] The battery pack of the present invention comprises: a plurality of stacked single cells; a holding member for holding the plurality of single cells; an adhesive member sandwiched between the single cells and the holding member for bonding the single cells to the holding member; and a thermally conductive member having a smaller elastic modulus than the adhesive member and sandwiched between the single cells and the holding member.

[0008] With this battery pack configuration, individual cells can be reliably secured to the holding member via the adhesive component. Furthermore, since the thermally conductive component, having a smaller elastic modulus than the adhesive component, is more easily deformable, it can easily deform in accordance with the deformation of the individual cell. Therefore, since the heat generated by the individual cell can be efficiently transferred to the holding member via the thermally conductive component, the individual cell can be cooled efficiently.

[0009] In addition, it is preferable that the thermal conductivity of the heat-conducting component is greater than that of the adhesive component.

[0010] With this battery pack configuration, heat from individual cells can be transferred more efficiently to the holding components via heat-conducting components.

[0011] Furthermore, the preferred single cell includes a rectangular bottom surface having a short side extending along the stacking direction of the single cell and a long side extending in a direction orthogonal to the stacking direction of the single cell. Adhesive components are disposed at both ends of the bottom surface in the direction orthogonal to the stacking direction of the single cell. A thermally conductive component is disposed at the center of the bottom surface in the direction orthogonal to the stacking direction of the single cell.

[0012] In this battery pack configuration, non-deformable adhesive components are positioned at both ends of the bottom surface, which exhibits relatively small deformation when a single cell deforms, while easily deformable heat-conducting components are positioned at the center of the bottom surface, which exhibits relatively large deformation when a single cell deforms. This allows for both more reliable fixation of the single cell to the retaining components and more efficient cooling of the single cell.

[0013] Additionally, the preferred single cell has a bottom surface and a side surface, the side surface rising from the bottom surface and having a smaller area than the bottom surface. An adhesive component is disposed on the side surface. A thermally conductive component is disposed on the bottom surface.

[0014] In this battery pack configuration, a non-deformable adhesive component is positioned on the side where the deformation is relatively small when a single cell deforms, while a deformable heat-conducting component is positioned on the bottom surface where the deformation is relatively large. This allows for both more reliable fixation of the single cell to the holding component and more efficient cooling of the single cell.

[0015] In addition, it is preferable that the contact area of ​​the thermally conductive component with respect to the single cell is greater than that of the adhesive component with respect to the single cell.

[0016] With this battery pack configuration, heat from individual cells can be efficiently transferred to the holding components via heat-conducting components.

[0017] Furthermore, it is preferable that the single cell has a thin plate shape in which the stacking direction of the single cell is the thickness direction. When viewed along the stacking direction of the single cell, the heat-conducting components are symmetrically arranged on both sides of the center line of the single cell extending in the vertical direction.

[0018] With this battery pack configuration, the individual cell can be cooled evenly on both sides of its centerline.

[0019] Alternatively, multiple individual cells are preferably formed into a single-cell stack. The retaining component has a facing surface opposite to the single-cell stack. The adhesive component is frame-shaped along the periphery of the facing surface. The thermally conductive component, made of a fluid thermally conductive material, is disposed in the central region of the facing surface enclosed by the adhesive component.

[0020] Based on this battery pack configuration, a mechanism can be easily constructed to hold a fluid heat-conducting component on the opposing surface.

[0021] The above and other objects, features, aspects, and advantages of the invention will become clear from the following detailed description of the invention as understood in conjunction with the accompanying drawings. Attached Figure Description

[0022] Figure 1 This is a cross-sectional view showing the battery pack in an embodiment of the present invention.

[0023] Figure 2 It indicates composition Figure 1 A 3D view of a single cell in the battery pack.

[0024] Figure 3 It means Figure 1 The exploded assembly diagram of the battery pack.

[0025] Figure 4 It is a schematic representation Figure 1 A 3D diagram of the battery pack assembly process.

[0026] Figure 5 It is a schematic diagram showing the deformed appearance of a single cell (bottom surface).

[0027] Figure 6 It means Figure 1 A cross-sectional view of the first modified example of the battery pack.

[0028] Figure 7 It is a schematic diagram showing the deformation of a single cell (bottom and fourth side).

[0029] Figure 8 It means Figure 1 A perspective view of the second modified example of the battery pack.

[0030] Figure 9 It means Figure 1 A perspective view of the third modified example of the battery pack. Detailed Implementation

[0031] Embodiments of the present invention will be described with reference to the accompanying drawings. In the drawings referred to below, identical or equivalent components are labeled with the same numbers.

[0032] Figure 1 This is a cross-sectional view showing the battery pack in an embodiment of the present invention. Figure 2 It indicates composition Figure 1 A 3D view of a single cell in the battery pack. Figure 3 It means Figure 1 The exploded assembly diagram of the battery pack.

[0033] Reference Figures 1-3 The battery pack 100 is used as a power source for driving vehicles such as hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (PHEV), or battery electric vehicles (BEV).

[0034] In this specification, for the convenience of explaining the structure of the battery pack 100, the axis extending horizontally in the stacking direction of the plurality of individual cells 11 described later is called the "Y-axis", the axis extending horizontally in the direction orthogonal to the Y-axis is called the "X-axis", and the axis extending vertically is called the "Z-axis".

[0035] The battery pack 100 has a plurality of individual cells 11 and a case body 21. The plurality of individual cells 11 are stacked along the Y-axis. The case body 21 holds the plurality of individual cells 11. The case body 21 holds the plurality of individual cells 11 in the space 70 described later. In this embodiment, the case body 21 corresponds to the "holding member" in this invention.

[0036] like Figure 2 As shown, the single cell 11 is a lithium-ion battery. The single cell 11 is square and has a rectangular plate shape. Multiple single cells 11 are stacked in such a way that the Y-axis direction is the thickness direction of the single cell 11.

[0037] The single battery 11 has an outer casing 12. The outer casing 12 is composed of a cuboid-shaped frame, which gives the appearance of the single battery 11. The outer casing 12 houses the electrodes and the electrolyte.

[0038] The outer casing 12 has a first side 13, a second side 14, a third side 19, a fourth side 20, a top surface 15, and a bottom surface 16. Each of the first side 13 and the second side 14 is formed by a plane orthogonal to the Y-axis. The first side 13 and the second side 14 face opposite sides in the Y-axis direction. Each of the first side 13 and the second side 14 has the largest area among the multiple sides of the outer casing 12.

[0039] The third side 19 and the fourth side 20 are each formed by a plane orthogonal to the X-axis. The third side 19 and the fourth side 20 face opposite sides in the X-axis direction. The third side 19 and the fourth side 20 each have an area smaller than the bottom surface 16. The third side 19 and the fourth side 20 each have the smallest area among the multiple sides of the outer body 12.

[0040] The top surface 15 and the bottom surface 16 are each formed by a plane orthogonal to the Z-axis. The top surface 15 faces upward. The bottom surface 16 faces downward. A gas discharge valve 17 is provided on the top surface 15. This gas discharge valve 17 is used to discharge gas to the outside of the outer casing 12 when the internal pressure of the outer casing 12 becomes higher than a specified value due to gas generated inside the outer casing 12.

[0041] Side 13, side 24, side 319, side 420, top surface 15, and bottom surface 16 are all rectangular in shape. Side 13 and side 214 are rectangular in shape with the X-axis as the length direction and the Z-axis as the width direction. Side 319 and side 420 are rectangular in shape with the Z-axis as the length direction and the Y-axis as the width direction. Top surface 15 and bottom surface 16 are rectangular in shape with the X-axis as the length direction and the Y-axis as the width direction.

[0042] The single cell 11 also has a pair of electrode terminals 18, namely a positive terminal 18P and a negative terminal 18N. The electrode terminals 18 are disposed on the top surface 15. The positive terminal 18P and the negative terminal 18N are configured to be separated from each other in the X-axis direction. The positive terminal 18P and the negative terminal 18N are respectively disposed on both sides of the gas discharge valve 17 in the X-axis direction.

[0043] Multiple individual cells 11 are stacked such that the first side 13 of adjacent individual cells 11, 11 faces each other and the second side 14 faces each other. Thus, in the Y-axis direction where the multiple individual cells 11 are stacked, the positive terminal 18P and the negative terminal 18N are arranged alternately.

[0044] Between adjacent cells 11, 11 along the Y-axis, the positive terminal 18P and the negative terminal 18N, arranged along the Y-axis, are interconnected via a busbar (not shown). Multiple cells 11 are connected in series.

[0045] A single-cell stack 10 is formed by stacking multiple individual cells 11 along the Y-axis. The single-cell stack 10 is cuboid in shape. The length of the single-cell stack 10 in the Y-axis direction is greater than the length of the single-cell stack 10 in the Z-axis direction, and also greater than the length of the single-cell stack 10 in the X-axis direction.

[0046] The box 21 is composed of a box with a cuboid shape. The length of the box 21 in the Y-axis direction is greater than the length of the box 21 in the Z-axis direction, and also greater than the length of the box 21 in the X-axis direction. The box 21 has a bottom 22, a side 23, and a top 24.

[0047] The bottom 22 is disposed at the bottom of the housing 21. The bottom 22 is made of a plate extending horizontally along the thickness direction in the Z-axis direction. A refrigerant passage 31 for refrigerant flow is provided in the bottom 22. The refrigerant passage 31 extends along the Y-axis direction. The side 23 rises upward from the periphery of the bottom 22. A space 70 is defined on the bottom 22, which is surrounded by the side 23, and opens upward to accommodate multiple individual cells 11 (single cell stack 10). The two ends of the multiple individual cells 11 in the Y-axis direction are constrained by the side 23. The side 23 causes a constraint force (compression force) in the Y-axis direction to act on the multiple individual cells 11.

[0048] The top 24 of the box is configured to face the bottom 22 of the box in the Z-axis direction. The top 24 forms a cover that is detachably mounted on the upper end of the side 23 of the box to seal the opening of the space 70.

[0049] Furthermore, the refrigerant passage 31 for supplying refrigerant is not limited to being located at the bottom 22 of the box; for example, it can also be located at a component that is different from the box body 21 but connected to the bottom 22 of the box.

[0050] Figure 4 It is a schematic representation Figure 1 A 3D diagram showing the battery pack assembly process. Figure 4 And what appeared later Figure 8 and Figure 9 The image shows only the bottom 22 of the box within the box 21. (See reference...) Figures 1-4 The battery pack 100 also has a heat-conducting component 41 and an adhesive component 51 (51A, 51B).

[0051] The thermally conductive component 41 is made of a different material than the adhesive component 51. The elastic modulus of the thermally conductive component 41 is less than that of the adhesive component 51. The thermal conductivity of the thermally conductive component 41 is greater than that of the adhesive component 51. The thermally conductive component 41 can be made of an adhesive material (adhesive) or a non-adhesive material.

[0052] The thermally conductive component 41 can be a thermally conductive sheet, thermally conductive grease, gap filler, or thermally conductive gel. The thermally conductive component 41 is made of materials such as acrylic, polyurethane, silicone, or modified silicone. The adhesive component 51 is made of materials such as epoxy resin, acrylic, polyurethane, organosilicone, or cyanoacrylate.

[0053] An adhesive component 51 is sandwiched between a single battery 11 and the housing 21. The adhesive component 51 is also sandwiched between multiple single batteries 11 (single battery stack 10) and the housing 21. The adhesive component 51 bonds the single batteries 11 and the housing 21. Multiple single batteries 11 (single battery stack 10) are fixed to the housing 21 by the adhesive component 51.

[0054] The heat-conducting component 41 is sandwiched between the single cell 11 and the housing 21. The heat-conducting component 41 is sandwiched between multiple single cells 11 (single cell stack 10) and the housing 21.

[0055] An adhesive component 51 is sandwiched between the bottom surface 16 of the single battery 11 and the bottom 22 of the casing 21. A heat-conducting component 41 is sandwiched between the bottom surface 16 of the single battery 11 and the bottom 22 of the casing 21. The adhesive component 51 is disposed at both ends of the bottom surface 16 in the X-axis direction. The heat-conducting component 41 is disposed at the center of the bottom surface 16 in the X-axis direction.

[0056] The heat-conducting component 41 extends in a strip shape along the Y-axis on the bottom 22 of the housing. Adhesive components 51A and 51B also extend in a strip shape along the Y-axis on the bottom 22 of the housing. The heat-conducting component 41 is positioned between adhesive components 51A and 51B in the X-axis direction. The heat-conducting component 41 is positioned to coincide with the gas discharge valve 17 when viewed along the Z-axis direction. Adhesive components 51A and 51B are positioned on either side of the gas discharge valve 17, offset towards the X-axis direction when viewed along the Z-axis direction.

[0057] The thermally conductive component 41 and the adhesive component 51 are configured to cover the entire surface of the bottom surface 16. The contact area of ​​the thermally conductive component 41 with respect to the single cell 11 is larger than the contact area of ​​the adhesive component 51 with respect to the single cell 11. Alternatively, the contact area of ​​the thermally conductive component 41 with respect to the single cell 11 may be smaller than the contact area of ​​the adhesive component 51 with respect to the single cell 11.

[0058] Observing battery pack 100 along the Y-axis direction Figure 1 The diagram shows the centerline 110 of a single cell 11 extending along the Z-axis (vertical direction). The single cell 11 (outer casing 12) has a symmetrical shape across the centerline 110. The positive terminal 18P is disposed on one side of the X-axis across the centerline 110, and the negative terminal 18N is disposed on the other side of the X-axis across the centerline 110. The length between the centerline 110 and the positive terminal 18P in the X-axis direction is equal to the length between the centerline 110 and the negative terminal 18N in the X-axis direction. Thermally conductive components 41 are symmetrically disposed on both sides of the centerline 110. The thermally conductive components 41 have a shape that completely overlaps when folded in a Y-axis-Z-axis plane including the centerline 110. Adhesive components 51 (51A, 51B) are symmetrically disposed on both sides of the centerline 110.

[0059] Figure 5 This is a schematic diagram showing the deformed appearance of a single cell (bottom surface). (Refer to...) Figure 5The single battery 11 (outer casing 12) deforms (expands) as it charges and discharges. If we consider the deformation of the bottom surface 16 at this time, the deformation of the bottom surface 16 in the Z-axis direction is relatively large at the center of the bottom surface 16 in the X-axis direction, and relatively small at both ends of the bottom surface 16 in the X-axis direction (Da > Db). This is because the outer casing 12, with its cuboid shape, is difficult to deform along its edges, and the deformation increases further away from the edges.

[0060] Reference Figures 1-5 In this embodiment, the single battery 11 can be reliably fixed to the housing 21 by means of the adhesive components 51 (51A, 51B) sandwiched between the single battery 11 and the housing 21.

[0061] Furthermore, since the heat-conducting component 41, which has a smaller elastic modulus than the adhesive component 51, is more easily deformable than the adhesive component 51, it can easily deform along with the deformation of the single cell 11. This suppresses the formation of gaps between the heat-conducting component 41 and the single cell 11 that would otherwise form a heat-insulating layer due to deformation of the single cell 11. As a result, the heat generated by the single cell 11 can be efficiently transferred through the heat-conducting component 41 to the bottom 22 of the housing 21, where the refrigerant passage 31 is provided, thus efficiently cooling the single cell 11, which serves as a heat source.

[0062] In this embodiment, particularly, non-deformable adhesive members 51 (51A, 51B) are provided at both ends of the bottom surface 16, which has a relatively small deformation amount, while a easily deformable heat-conducting member 41 is provided at the center of the bottom surface 16, which has a relatively large deformation amount. This structure suppresses gaps that may form between the adhesive member 51 and the single cell 11, and between the heat-conducting member 41 and the single cell 11, due to deformation of the single cell 11. Furthermore, the thermal conductivity of the heat-conducting member 41 is greater than that of the adhesive member 51. Therefore, the single cell 11 can be more reliably fixed to the housing 21, and the single cell 11 can be cooled more efficiently.

[0063] Furthermore, since the contact area of ​​the heat-conducting component 41 with respect to the single cell 11 is larger than the contact area of ​​the adhesive component 51 with respect to the single cell 11, heat transfer from the single cell 11 to the housing 21 can be promoted. In addition, since the heat-conducting component 41 is symmetrically arranged across the center line 110 of the single cell 11, the single cell 11 can be cooled evenly on both sides across the center line 110.

[0064] Figure 6 It means Figure 1 A cross-sectional view of the first modified example of the battery pack. Figure 6 The text shows the relationship with... Figure 1 The corresponding cross-section of the battery pack. Figure 7It is a schematic diagram showing the deformation of a single cell (bottom and fourth side).

[0065] Reference Figure 6 as well as Figure 7 In this modified example, adhesive components 51 (51A, 51B) are sandwiched between the third side 19 and the fourth side 20 of the single battery 11 and the box side 23 of the housing 21. Thermally conductive component 41 is sandwiched between the bottom surface 16 of the single battery 11 and the bottom 22 of the housing 21.

[0066] The heat-conducting component 41 extends in a strip shape along the Y-axis on the bottom 22 of the enclosure. The heat-conducting component 41 is symmetrically arranged on both sides separated by the center line 110. The adhesive components 51A and 51B each extend in a strip shape along the Y-axis on the side 23 of the enclosure. The adhesive components 51 (51A, 51B) are symmetrically arranged on both sides separated by the center line 110.

[0067] like Figure 7 As shown, if we focus on the deformation of the bottom surface 16 and the fourth side surface 20 (the third side surface 19 is the same as the fourth side surface 20) when the single cell 11 expands, the deformation of the bottom surface 16 in the Z-axis direction is greater than the deformation of the fourth side surface 20 (the third side surface 19) in the X-axis direction (Dc > De). This is because the bottom surface 16 has a larger area than the third side surface 19 and the fourth side surface 20, making it easier to deform.

[0068] In this modified example, non-deformable adhesive components 51 (51A, 51B) are disposed on the third side 19 and the fourth side 20, which have relatively small deformation amounts, while easily deformable heat-conducting components 41 are disposed on the bottom surface 16, which has relatively large deformation amounts.

[0069] Figure 8 It means Figure 1 A perspective view of the second modified example of the battery pack. Figure 8 and Figure 4 Corresponding. Reference Figure 8 The housing 21 (bottom 22) has an opposing surface 22a. The opposing surface 22a divides the space 70 and is opposite to the single-cell stack 10. The opposing surface 22a has a rectangular shape with the Y-axis as the length direction and the X-axis as the width direction.

[0070] In this modified example, the adhesive component 51 is frame-shaped along the periphery of the opposing surface 22a. The adhesive component 51 is disposed along the end edge of the opposing surface 22a, which has a rectangular shape. The thermally conductive component 41 is made of a fluid thermally conductive material (such as thermal grease or thermal gel). The thermally conductive component 41 is disposed in the central region of the opposing surface 22a enclosed by the adhesive component 51.

[0071] With this structure, during battery assembly, after the adhesive component 51 is coated onto the opposing surface 22a, the thermally conductive component 41 is disposed inside the adhesive component 51. A single-cell laminate 10 is disposed on the adhesive component 51 and the thermally conductive component 41, and the adhesive component 51 is then cured. Thus, the thermally conductive component 41, made of heat-conduction grease or thermally conductive gel, can be held on the opposing surface 22a using the adhesive component 51.

[0072] Figure 9 It means Figure 1 A perspective view of the third modified example of the battery pack. Figure 9 and Figure 4 Corresponding. Reference Figure 9 The battery pack in this modified example also has a binding bar 61. The binding bar 61 extends along the Y-axis. The binding bar 61 is disposed in the X-axis direction at positions opposite to the third side 19 and the fourth side 20 of the single cell 11.

[0073] An adhesive component 51 is clamped between the third side 19 and the fourth side 20 of the single battery 11 and the constraint rod 61. The constraint rod 61 holds the multiple single batteries 11 together. The constraint rod 61 is connected to the side portion 23 of the housing 21. A heat-conducting component 41 is clamped between the bottom surface 16 of the single battery 11 and the bottom 22 of the housing 21. In this modified example, the housing 21 and the constraint rod 61 correspond to the holding component in this invention.

[0074] Embodiments of the present invention have been described, but it should be considered that the embodiments disclosed herein are illustrative in all respects and not restrictive. The scope of the present invention is shown by the technical solutions claimed in the present invention, and is intended to include all modifications within the scope and meaning equivalent to the technical solutions claimed in the present invention.

Claims

1. A battery pack, characterized in that, have: Multiple single cells stacked together; A retaining component that holds multiple of the aforementioned single cells; An adhesive component, sandwiched between the single battery and the retaining component, adhesively bonds the single battery and the retaining component; and A thermally conductive component, having a smaller elastic modulus than the aforementioned adhesive component, is sandwiched between the aforementioned single cell and the aforementioned retaining component. The aforementioned single cell includes a rectangular bottom surface, the rectangular shape having a short side extending along the stacking direction of the single cell and a long side extending in a direction orthogonal to the stacking direction of the single cell. The aforementioned adhesive components include: a first adhesive component disposed at one end of the bottom surface in a direction orthogonal to the stacking direction of the single cell; and a second adhesive component disposed at the other end of the bottom surface in a direction orthogonal to the stacking direction of the single cell and independent of the first adhesive component. The aforementioned heat-conducting component is disposed at the center of the bottom surface in a direction orthogonal to the stacking direction of the aforementioned single cell, and is configured to fill the space between the aforementioned first adhesive component and the aforementioned second adhesive component in a direction orthogonal to the stacking direction of the aforementioned single cell.

2. A battery pack, characterized in that, have: Multiple single cells stacked together; A retaining component that holds multiple of the aforementioned single cells; An adhesive component, sandwiched between the single battery and the retaining component, adhesively bonds the single battery and the retaining component; and A thermally conductive component, having a smaller elastic modulus than the aforementioned adhesive component, is sandwiched between the aforementioned single cell and the aforementioned retaining component. Multiple of the above-mentioned single cells constitute a single cell stack. The aforementioned retaining member has an opposing surface that faces the aforementioned single-cell stack. The aforementioned adhesive component is frame-shaped along the periphery of the aforementioned opposing surfaces. The aforementioned heat-conducting component is made of a fluid heat-conducting material and is disposed in the central region of the opposing surface enclosed by the aforementioned adhesive component.

3. The battery pack according to claim 1 or 2, characterized in that, The thermal conductivity of the aforementioned heat-conducting component is greater than that of the aforementioned adhesive component.

4. The battery pack according to claim 1 or 2, characterized in that, The contact area of ​​the aforementioned thermally conductive component with respect to the aforementioned single cell is greater than the contact area of ​​the aforementioned adhesive component with respect to the aforementioned single cell.

5. The battery pack according to claim 1 or 2, characterized in that, The aforementioned single cell has a thin plate shape in which the stacking direction of the single cell is the thickness direction. When viewed along the stacking direction of the aforementioned single cells, the aforementioned heat-conducting components are symmetrically arranged on both sides of the center line of the aforementioned single cells extending in the vertical direction.

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