Electricity storage device and vehicle-mounted structure thereof

Abstract

The present application relates to an electric power storage device and a vehicle mounting structure thereof. The electric power storage device includes a first housing (100) that houses a plurality of first electric power storage cells (10A) stacked, and a second housing (200) that houses a plurality of second electric power storage cells (10B) stacked. The first housing (100) has a first reinforcing portion (120, 30A) extending in a first direction, and the second housing (200) has a second reinforcing portion (220, 30B) extending in a second direction intersecting the first direction. The first housing (100) and the second housing (200) are disposed in overlap along a third direction intersecting the first direction and the second direction, and are engaged with each other.

Description

Technical Field

[0001] This invention relates to an energy storage device and its vehicle mounting structure. Background Technology

[0002] Vehicle-mounted structures that serve as energy storage devices (battery packs) include, for example, those described in Japanese Patent Application Publication Nos. 2012-101663 and 2016-132314.

[0003] There is a need to improve the vibration resistance of energy storage devices. On the other hand, the reinforcement structure designed to improve vibration resistance may reduce the housing efficiency of individual cells within the casing. As a result, there are concerns that energy storage devices will become larger and their energy density will decrease. Conventional reinforcement structures, which can eliminate these concerns, may not be sufficient. Summary of the Invention

[0004] The purpose of this invention is to provide an energy storage device and its vehicle mounting structure that can achieve increased energy density, miniaturization, and improved vibration resistance.

[0005] The energy storage device of the present invention includes a first housing housing a plurality of stacked first energy storage cells and a second housing housing a plurality of stacked second energy storage cells. The first housing has a first reinforcing portion extending in a first direction, and the second housing has a second reinforcing portion extending in a second direction intersecting the first direction. The first housing and the second housing are disposed overlappingly along a third direction intersecting the first and second directions and are joined together.

[0006] The above and other objects, features, aspects and advantages of the invention will become apparent from the following detailed description of the invention, taken in conjunction with the accompanying drawings. Attached Figure Description

[0007] Figure 1 This is a diagram representing a single battery cell.

[0008] Figure 2 This is a perspective view showing the first housing of the battery pack according to Embodiment 1.

[0009] Figure 3 This is a perspective view showing the second housing of the battery pack according to Embodiment 1.

[0010] Figure 4 This is a top view showing the state in which the battery cells are housed in the first housing of the battery pack in Embodiment 1.

[0011] Figure 5 This is a top view showing the state in which the battery cells are housed in the second housing of the battery pack in Embodiment 1.

[0012] Figure 6This is a cross-sectional view of the battery pack in Embodiment 1.

[0013] Figure 7 This is a top view showing the state in which the battery cells are housed in the first housing of the battery pack in Embodiment 2.

[0014] Figure 8 This is a top view showing the state in which the battery cells are housed in the second housing of the battery pack in Embodiment 2.

[0015] Figure 9 This is a top view showing the state in which the battery cells are housed in the first housing of the battery pack in Embodiment 3.

[0016] Figure 10 This is a top view showing the state in which the battery cells are housed in the second housing of the battery pack in Embodiment 3.

[0017] Figure 11 and Figure 12 This is a magnified view of a portion of the casing and individual battery cells.

[0018] Figures 13 to 15 This is a diagram illustrating an example of the joint structure of the first and second housings.

[0019] Figure 16 It means in Figure 15 The diagram shows the state of the joint structure with the adhesive portion.

[0020] Figure 17 This is another example of the joint structure of the first and second housings.

[0021] Figure 18 It means in Figure 17 The diagram shows the state of the joint structure with the adhesive portion.

[0022] Figures 19 to 22 The diagram shows another example of the joint structure of the first and second housings.

[0023] Figure 23 This is a flowchart illustrating the manufacturing process of a battery pack.

[0024] Figures 24 to 26 It is used for explanation Figure 23 The flowchart is shown. Detailed Implementation

[0025] The embodiments of the present invention will be described below. Sometimes the same or equivalent parts are labeled with the same reference numerals, and their description will not be repeated.

[0026] Furthermore, in the embodiments described below, when numbers, quantities, etc., are mentioned, the scope of the present invention is not necessarily limited to those numbers, quantities, etc., unless specifically stated otherwise. Additionally, in the embodiments described below, each constituent element is not necessarily essential to the present invention unless specifically stated otherwise. Furthermore, the present invention is not necessarily limited to achieving all the effects mentioned in these embodiments.

[0027] Furthermore, in this specification, the terms "comprise," "include," and "have" are open-ended. That is, when a structure is included, it may or may not include other structures besides that structure.

[0028] Furthermore, in this specification, when using geometric terms and terms indicating positional or directional relationships, such as "parallel," "orthogonal," "45° oblique," "coaxial," and "along," slight manufacturing errors or variations are permissible. In this specification, when using terms indicating relative positional relationships such as "upper side" and "lower side," these terms are used to indicate the relative positional relationship in a given state. This relative positional relationship can be flipped or rotated to any angle by adjusting the orientation of each mechanism (e.g., by flipping the entire mechanism up or down).

[0029] In this specification, "battery" is not limited to lithium-ion batteries and may include other batteries such as nickel-metal hydride batteries. In this specification, "electrode" can be a general term for both positive and negative electrodes. Additionally, "electrode plate" can be a general term for both positive and negative electrode plates.

[0030] In this specification, when the terms "energy storage cell" or "energy storage device" are used, "energy storage cell" or "energy storage device" is not limited to a single battery cell or battery module, and may include, for example, a capacitor.

[0031] Figure 1 This is a diagram representing battery cell 10. (For example...) Figure 1 As shown, the battery cell 10 is formed into a generally rectangular parallelepiped shape with a flat surface. The battery cells 10 are stacked in the Y-axis direction. The electrode terminals 11 include a positive terminal 11A and a negative terminal 11B. The positive terminal 11A and the negative terminal 11B are arranged in the X-axis direction. The electrode terminals 11 are disposed on the upper surface of a square frame 12. The upper and bottom surfaces of the frame 12 have a generally rectangular shape in which the X-axis direction is the long side direction and the Y-axis direction is the short side direction. The electrode body and electrolyte are housed in the frame 12.

[0032] (Implementation Method 1)

[0033] Figure 2 , Figure 3 These are perspective views showing the first housing 100 and the second housing 200 of the battery pack according to Embodiment 1.

[0034] like Figure 2 As shown, the first housing 100 has a main body 110 and a rib 120 (first reinforcement) extending in the DR1 direction (first direction). The rib 120 is configured to protrude from the bottom surface (first bottom surface) of the main body 110 of the first housing 100. The rib 120 extends along the DR1 direction in the entire width direction of the first housing 100.

[0035] like Figure 3 As shown, the second housing 200 has a rib 220 (second reinforcing part) extending in a DR2 direction that is substantially orthogonal (intersecting) with the DR1 direction. The intersection of the DR1 and DR2 directions is not necessarily limited to orthogonality. The rib 220 is configured to protrude from the bottom surface (second bottom surface) of the body 210 of the second housing 200. The rib 220 extends along the DR2 direction in the entire width direction of the second housing 200. The rib 220 includes three ribs 221, 222, and 223 arranged in the DR1 direction.

[0036] Figure 4 , Figure 5 These are top views showing the state in which the battery cells 10 are housed in the first housing 100 and the second housing 200.

[0037] like Figure 4 As shown, the first housing 100 houses a plurality of stacked battery cells 10A (first energy storage cells). The main body 110 of the first housing 100 has a first wall surface 111 at both ends in the DR1 direction and a second wall surface 112 at both ends in the DR2 direction. The battery cells 10A at the ends are directly supported on the first wall surface 111 (wall portion) of the first housing 100.

[0038] like Figure 5 As shown, the second housing 200 houses a plurality of stacked battery cells 10B (second energy storage cells). The main body 210 of the second housing 200 has a first wall surface 211 at both ends in the DR1 direction and a second wall surface 212 at both ends in the DR2 direction. The battery cells 10B at the ends are directly supported on the second wall surface 212 (wall portion) of the second housing 200.

[0039] Thus, in this embodiment, the stacking direction of the battery cells 10 (10A, 10B) is the same as the extension direction of the ribs 120, 220.

[0040] Figure 6 This is a cross-sectional view of the battery pack in this embodiment. Figure 6As shown, the first housing 100 and the second housing 200 overlap along the DR3 direction (third direction), which intersects the DR1 and DR2 directions. Insulating spacers 20 are respectively provided between the plurality of battery cells 10 (10A, 10B).

[0041] The overlapping first housing 100 and second housing 200 are joined together. As a typical example, the first housing 100 and the second housing 200 are joined by welding, but the joining method of the first housing 100 and the second housing 200 is not limited to welding. In addition, other housings may also overlap in addition to the first housing 100 and the second housing 200.

[0042] The battery pack of this embodiment has a structure in which a first housing 100 having ribs 120 extending in the DR1 direction and a second housing 200 having ribs 220 extending in the DR2 direction are joined. In this structure, the rigidity in the DR1 direction can be improved by the ribs 120, and the rigidity in the DR2 direction can be improved by the ribs 220. Therefore, even if each housing has only one rib (rib 120 or rib 220) in one direction (DR1 direction or DR2 direction), the vibration resistance in both orthogonal directions (DR1 direction and DR2 direction) can be improved. As a result, the housing efficiency of the battery cell 10 can be improved, and the vibration resistance of the battery pack can be improved while achieving increased energy density and miniaturization.

[0043] (Implementation Method 2)

[0044] Figure 7 , Figure 8 These are top views showing the state in which the battery pack in Embodiment 2 has battery cells 10 housed in the first housing 100 and the second housing 200.

[0045] like Figure 7 As shown, the first housing 100 has a main body 110 and a rib 120 (first reinforcement) extending in the DR1 direction (first direction). The first housing 100 houses a plurality of battery cells 10A (first energy storage cells) stacked in the DR2 direction.

[0046] like Figure 8 As shown, the second housing 200 has a main body 210 and a rib 220 (second reinforcement) extending in the DR2 direction (second direction). The second housing 200 houses a plurality of battery cells 10B (second energy storage cells) stacked in the DR1 direction.

[0047] Thus, in this embodiment, the stacking direction of the battery cells 10 (10A, 10B) is approximately orthogonal to the extension direction of the ribs 120, 220.

[0048] In this embodiment, similar to Embodiment 1, the rigidity in the DR1 direction can be improved by rib 120, and the rigidity in the DR2 direction can be improved by rib 220. Therefore, even if only one direction (DR1 direction or DR2 direction) of ribs (rib 120 or rib 220) is provided in each housing, the vibration resistance in both orthogonal directions (DR1 direction and DR2 direction) can be improved. As a result, the housing efficiency of the battery cell 10 can be improved, and the vibration resistance of the battery pack can be improved while achieving increased energy density and miniaturization.

[0049] (Implementation Method 3)

[0050] Figure 9 , Figure 10 These are top views showing the state in which the battery pack in Embodiment 3 has battery cells 10 housed in the first housing 100 and the second housing 200.

[0051] like Figure 9 , Figure 10 As shown, the battery pack of this embodiment includes a constraint member 30A (first constraint member) that constrains a plurality of battery cells 10A along the DR1 direction and a constraint member 30B (second constraint member) that constrains a plurality of battery cells 10B along the DR2 direction. The constraint members 30A and 30B are fixed to end plates 40A and 40B disposed at both ends of the plurality of battery cells 10A and 10B.

[0052] In manufacturing a battery pack including constraint members 30A and 30B and end plates 40A and 40B, firstly, multiple battery cells 10A and 10B are stacked along the Y-axis direction. Next, end plates 40A and 40B are provided at both ends of the stacked battery cells 10A and 10B. Then, the multiple battery cells 10A and 10B and the end plates 40A and 40B are constrained by the constraint members 30A and 30B in the Y-axis direction. The battery pack thus constructed is fixed inside the first housing 100 and the second housing 200.

[0053] In this embodiment, the ribs 120 and 220 described in embodiments 1 and 2 are not provided. However, the constraint member 30A extending in the DR1 direction can function as a "first reinforcement" in the same way as the rib 120. Similarly, the constraint member 30B extending in the DR2 direction can function as a "second reinforcement" in the same way as the rib 220. Therefore, vibration resistance in both orthogonal directions (DR1 and DR2 directions) can be improved without providing the ribs 120 and 220. As a result, the housing efficiency of the battery cell 10 can be improved, and the vibration resistance of the battery pack can be improved while achieving increased energy density and miniaturization.

[0054] (Shape of the shell)

[0055] Figure 11 , Figure 12 This is a magnified view of a portion of the casing and individual battery cells.

[0056] exist Figure 11 In this example, the thickness (T1) of the first wall surface 111 that directly supports the battery cell 10 is made thicker than the thickness (T2) of the second wall surface 112. This increases the strength of the first wall surface 111, which is subjected to the reaction force of the battery cell 10.

[0057] exist Figure 12 In the example, a cavity 113 is formed in the first wall surface 111 that directly supports the battery cell 10. As a result, the heat generated when the first housing 100 and the second housing 200 are joined by welding is not easily transferred to the battery cell 10, thus reducing the thermal impact on the battery cell 10.

[0058] (The joint structure of the shell)

[0059] Figures 13-22 This is a diagram illustrating an example of the joint structure of the first housing 100 and the second housing 200.

[0060] exist Figure 13 In the example, the first housing 100 and the second housing 200 have flange portions 1 that protrude outward toward the outer side of the first housing 100 and the second housing 200. The flange portions 1 are engaged with each other or with the upper cover 300 by bolt fastening portions 2.

[0061] exist Figure 14 In the example, the first housing 100, the second housing 200, and the top cover 300 are joined by the adhesive part 3.

[0062] exist Figure 15 , Figure 16 In this example, the second housing 200 and the top cover 300 are also joined by the adhesive portion 3. Here, the end face of the second housing 200 forming the adhesive portion 3 has a protrusion and a recess 4.

[0063] exist Figure 17 , Figure 18 In this example, the second housing 200 and the top cover 300 are also joined by an adhesive portion 3. Here, the end face of the second housing 200 forming the adhesive portion 3 has a recess 5. A protrusion 6 is formed on the top cover 300 at a position opposite to the recess 5. The protrusion 6 is housed within the recess 5.

[0064] like Figures 15-18 As in the example, the joint surface between the second housing 200 and the top cover 300 is provided with uneven portions, so that the adhesive is reliably retained on the joint surface, ensuring the bonding strength. In addition, the bonding area is increased by the uneven portions, thus improving the bonding strength.

[0065] Figures 15-18The convex-concave structure shown can also be applied to the mating surfaces of the first housing 100 and the second housing 200.

[0066] exist Figure 19 In the example, the first housing 100, the second housing 200, and the top cover 300 are joined by the welding part 7.

[0067] exist Figure 20 In this example, the second housing 200 and the top cover 300 are also joined by a welded portion 7. Here, the end face of the second housing 200 forming the welded portion 7 has an inclined surface 8. The inclined surface 8 is inclined from the outside of the second housing 200 toward the inside, away from the lower surface (facing surface) of the top cover 300. The welded portion 7 is formed from the front end side of the inclined surface 8, that is, the outside of the second housing 200. As a result, the second housing 200 forming the welded portion 7 can be brought close to the top cover 300, and therefore, welding can be performed reliably.

[0068] Figure 20 The inclined surface 8 shown can also be applied to the mating surface of the first housing 100 and the second housing 200.

[0069] exist Figure 21 In this example, the first housing 100, the second housing 200, and the top cover 300 are also joined by a welded portion 7. The welded portion 7 is formed on the flange portion 1 of the first housing 100 and the second housing 200.

[0070] like Figure 21 As shown, a flange 1 is formed on the lower part of the component, thereby enabling the welding part 7 to be formed from the upper part, thus improving the workability of welding.

[0071] exist Figure 22 In the example, a welding portion 7 is also formed in the flange portion 1. Here, a stepped portion 9 is formed in the flange portion 1. The stepped portion 9 allows for the positioning of the component to be welded.

[0072] (Manufacturing process)

[0073] Figure 23 This is a flowchart illustrating the manufacturing process of a battery pack. Figures 24-26 It means Figure 23 A diagram showing the status of each process step. Furthermore, in Figures 24-26 For ease of illustration and explanation, only the first housing 100 is shown, but the same applies to the second housing 200.

[0074] like Figures 23-26 As shown, the manufacturing process of the battery pack includes: a process of applying an adhesive to the bottom surface 100A of the first housing 100 (S10: Figure 24 The process of inserting the battery cell 10 into the first housing 100 (S20): Figure 25The process of inserting the busbar plate 50, which is equipped with busbars and voltage detection lines, into the battery cell 10 (S30: Figure 26 The process of fastening the electrode terminals and busbar of the battery cell 10 (S40); the process of fastening the connector 60 for external connection (S50). Figure 26 The process of stacking and fixing the first housing 100 and the second housing 200 (S60); and the process of installing the top cover 300 (S70).

[0075] like Figure 24 , Figure 25 As shown, the hole 100B for the connector 60 is open in a direction perpendicular to the stacking direction (Y-axis direction) of the battery cell 10.

[0076] (Carrying onto the vehicle)

[0077] The battery pack described above can be mounted in a vehicle. For example, the DR1 direction can be set as the vehicle's longitudinal direction, and the DR2 direction as the vehicle's width direction. This results in a vehicle mounting structure with high vibration resistance in both the longitudinal and width directions.

[0078] Embodiments of the present invention have been described, but should be considered as illustrative rather than restrictive in all respects. The scope of the invention is defined by the claims and is intended to include all modifications within the meaning and scope equivalent to the claims.

Claims

1. An energy storage device, wherein, have: The first housing, which houses multiple stacked first energy storage cells; and The second casing houses multiple stacked second battery cells. The first housing has a first reinforcing portion extending in a first direction. The second housing has a second reinforcing portion extending in a second direction intersecting the first direction. The first housing and the second housing are arranged overlappingly along a third direction that intersects the first and second directions, and are joined together. The stacking direction of the plurality of first energy storage cells within the first housing is orthogonal to the stacking direction of the plurality of second energy storage cells within the second housing. The first housing has a first bottom surface, and the first reinforcing portion is configured to protrude from the first bottom surface. The second housing has a second bottom surface, and the second reinforcing part is configured to protrude from the second bottom surface.

2. The energy storage device according to claim 1, wherein, The first direction and the second direction are orthogonal.

3. The energy storage device according to claim 1 or 2, wherein, The first reinforcing portion extends along the first direction throughout the width of the first housing. The second reinforcing portion extends along the second direction throughout the width of the second housing.

4. The energy storage device according to claim 1 or 2, wherein, The plurality of first energy storage cells are directly supported by the wall of the first housing. The plurality of second energy storage cells are directly supported on the wall of the second housing.

5. The energy storage device according to claim 1 or 2, wherein, It also has: A first constraint member constrains the plurality of first energy storage cells along the first direction; and The second constraint member constrains the plurality of second energy storage cells along the second direction. The first reinforcing part includes the first constraint member. The second reinforcing part includes the second constraint member.

6. The energy storage device according to claim 1 or 2, wherein, The first housing and the second housing are joined together by welding.

7. The energy storage device according to claim 1 or 2, wherein, At least one of the first housing and the second housing has an end face including a protrusion and a recess. The first housing and the second housing are joined by an adhesive portion formed on the end face.

8. The energy storage device according to claim 1 or 2, wherein, At least one of the first housing and the second housing has an end face including an inclined surface. A welded portion is formed on the front end side of the inclined surface.

9. The energy storage device according to claim 1 or 2, wherein, At least one of the first housing and the second housing has a flange portion that protrudes outward toward the outer side of the first housing and the second housing. A welded portion is formed on the flange portion.

10. The energy storage device according to claim 9, wherein, The flange portion includes a stepped portion.

11. A vehicle mounting structure, wherein the energy storage device according to any one of claims 1 to 10 is mounted in a vehicle, wherein, The first direction is the front-to-back direction of the vehicle, and the second direction is the width direction of the vehicle.

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