Battery packs and battery cases

Abstract

A battery case that comprises a battery housing part and at least one gas exhaust passage. The battery housing part has: a battery housing chamber that houses a plurality of batteries; and an inside gas exhaust hole that is for discharging gas that has been generated by the batteries to at least one side in the height direction of the batteries as fixed in the battery housing chamber. The at least one gas exhaust passage has: first and second corner part passage parts that are located outside the battery housing part but inside an outer wall part that has an outer surface that contacts an outside area and extend along the height direction; and an outside gas exhaust hole that is for discharging gas to the outside. The at least one gas exhaust passage guides gas from the inside gas exhaust hole to the outside gas exhaust hole.

Description

[Technical Field]

[0001] The present disclosure relates to a battery case and a battery pack. [Background technology]

[0002] A conventional battery pack is described in Patent Document 1. This battery pack has a duct through which gas released from the battery when the battery generates abnormal heat is circulated. This battery pack reduces the temperature of the gas in the duct and discharges the cooled gas to the outside, ensuring safety when the battery generates abnormal heat. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5378670 Summary of the Invention [Problem to be solved by the invention]

[0004] The battery pack requires the installation of ducts throughout the battery pack, which tends to make the structure complex and increases the manufacturing costs.

[0005] Therefore, an object of the present disclosure is to provide a battery case and a battery pack that can efficiently cool gas released from a battery when the battery generates abnormal heat, using a simple structure and at low cost. [Means for solving the problem]

[0006] In order to solve the above problems, the battery case of the present disclosure comprises a battery housing chamber that houses multiple cylindrical batteries, a battery housing section having an inner gas exhaust section for exhausting gas generated in the cylindrical batteries on at least one heightwise side of the cylindrical batteries fixed to the battery housing chamber, and one or more gas exhaust passages that guide the gas from the inner gas exhaust section side to the outer gas exhaust section side, the heightwise passage section being located inside an outer wall section having an outer surface that contacts the outer region and outside the battery housing section, and having an outer gas exhaust section for exhausting the gas to the outside.

[0007] The inner gas discharge portion may be configured as at least one of one or more inner holes and one or more inner breakable portions that break when the internal pressure of the battery accommodating chamber reaches or exceeds a first predetermined pressure. The outer gas discharge portion may be configured as at least one of one or more outer holes and one or more outer breakable portions that break when the internal pressure of the case accommodating chamber reaches or exceeds a second predetermined pressure. In such a configuration, the first predetermined pressure may be the same as the second predetermined pressure or may be different from the second predetermined pressure.

[0008] A battery pack according to the present disclosure includes the battery case according to the present disclosure and a plurality of batteries arranged in the battery housing chamber of the battery case. [Effects of the Invention]

[0009] According to the present disclosure, it is possible to realize a battery case and a battery pack that can efficiently cool gas released from a battery when the battery generates abnormal heat, with a simple structure and at low cost. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a perspective view of a battery pack according to a first embodiment of the present disclosure. [Figure 2] FIG. 2 is a cross-sectional view taken along line AA in FIG. [Figure 3] FIG. 2 is a perspective view showing the internal structure of the battery pack. [Figure 4]3 is an enlarged perspective view showing the internal structure of one end portion of the battery in the height direction of the battery pack. FIG. [Figure 5] FIG. 10 is a perspective view of a battery pack according to a second embodiment of the present disclosure. [Figure 6] 6 is a schematic cross-sectional view corresponding to the schematic cross-sectional view of the battery pack according to a third embodiment of the present disclosure taken along line EE in FIG. 1. FIG. [Figure 7] FIG. 7 is a schematic cross-sectional view corresponding to FIG. 6 of a battery pack according to a fourth embodiment of the present disclosure. [Figure 8] FIG. 10 is a schematic cross-sectional view corresponding to FIG. 6 of a battery pack according to a fifth embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0011] Embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. It is anticipated that, when multiple embodiments and variations are included below, new embodiments can be constructed by appropriately combining their characteristic features. In the following examples, identical components are designated by the same reference numerals in the drawings, and redundant description will be omitted. The drawings include schematic diagrams, and the dimensional ratios of the length, width, height, and other dimensions of each component do not necessarily match between different drawings. Among the components described below, components not recited in the independent claims that represent the highest concept are optional components and are not essential components. In this specification, the term "approximately" is used in the same sense as "approximately," and the requirement of "approximately" is met if the components are substantially the same. In the drawings and the following examples, the X direction is the height direction (axial direction) of the cylindrical batteries 18 (hereinafter simply referred to as batteries 18), and the Y direction is the direction in which the multiple batteries 18 are arranged in multiple rows. The Z direction is the height direction (thickness direction) of the battery packs 1, 101, 201, 301, 401 (battery cases 10, 110, 210, 410). The X direction, Y direction, and Z direction are perpendicular to each other.

[0012] (First embodiment) FIG. 1 is a perspective view of a battery pack 1 according to a first embodiment of the present disclosure. FIG. 2 is a cross-sectional view taken along line AA in FIG. 1, and FIG. 3 is a perspective view showing the internal structure of the battery pack 1. FIG. 4 is an enlarged perspective view showing the internal structure of one end of the battery pack 1 in the X direction. Note that, in the perspective views of FIGS. 3 and 4, the internal structure of the battery pack 1 would actually need to be depicted using two-dot chain lines (imaginary lines), but is depicted using thin solid lines for ease of understanding. In the first embodiment, the X direction coincides with the longitudinal direction of the battery pack 1 (battery case 10), and the Y direction coincides with the width direction (short direction) of the battery pack 1 (battery case 10).

[0013] As shown in FIG. 1, the battery pack 1 has a semi-cylindrical shape and has two outer gas exhaust holes 2a, 2b as an example of an outer gas exhaust portion on one side in the X direction. As shown in FIG. 2, the battery pack 1 includes a battery case 10 and a plurality of batteries 18. The battery case 10 has an upper cover member 2 as a first member and a base member 3 as a second member. The upper cover member 2 and the base member 3 are formed of, for example, a resin material or a metal material. The upper cover member 2 has a thick portion 5, a first thin portion 6, a second thin portion 7, a first closing portion 8 (see FIG. 3), and a second closing portion 9 (see FIG. 3), and at least the thick portion 5, the first thin portion 6, and the second thin portion 7 are integrally molded.

[0014] The thick-walled portion 5 includes a flat lid portion 5a and two curved lid portions 5b, 5c. The flat lid portion 5a has a flat plate shape and extends approximately parallel to the XY plane. The first curved lid portion 5b curves so as to displace toward one side in the Z direction as it moves from one end of the flat lid portion 5a in the Y direction to the outside in the Y direction. An end face 11 of the first curved lid portion 5b at the end opposite the flat lid portion 5a faces one side in the Z direction. Similarly, the second curved lid portion 5c curves so as to displace toward one side in the Z direction as it moves from the other end of the flat lid portion 5a in the Y direction to the outside in the Y direction. An end face 12 of the second curved lid portion 5c at the end opposite the flat lid portion 5a faces one side in the Z direction.

[0015] In the first embodiment, the upper cover member 2 is described as having two lid curved portions 5b, 5c, but the upper cover member does not have to have lid curved portions, and instead of the two lid curved portions, the upper cover member may have two lateral flat plate portions that protrude in the Z direction from both Y-direction ends of the lid flat plate portion that extends approximately parallel to the XY plane and extend approximately parallel to the XZ plane.

[0016] Thin-walled portion 6 protrudes to one side in the Z direction from a part of end face 11 that is outer in the X direction, while thin-walled portion 7 protrudes to one side in the Z direction from a part of end face 12 that is outer in the X direction. As shown in Fig. 3, the two lid curved portions 5b, 5c and the two thin-walled portions 6, 7 extend in the X direction. The first closing portion 8 is arranged to tightly close the opening on one side in the X direction of the gutter-shaped groove defined by the lid flat portion 5a, the two lid curved portions 5b, 5c, and the two thin-walled portions 6, 7, and the second closing portion 9 is arranged to tightly close the opening on the other side in the X direction of the gutter-shaped groove.

[0017] Referring again to FIG. 2 , the base member 3 has an X-direction dimension substantially equal to the X-direction dimension of the top cover member 2, and a Y-direction dimension substantially equal to the Y-direction dimension of the top cover member 2. The base member 3 includes a base plate portion 15, a first base-support curved portion 16, and a second base-support curved portion 17. The first base-support curved portion 16 branches off from one Y-direction side of the base plate portion 15 on one Y-direction side of the base member 3 and curves so as to displace toward the other Z-direction as it approaches that side in the Y-direction. The end face on the other Z-direction side of the first base-support curved portion 16 faces a step portion of the cover curved portion 5b formed by the difference in thickness between the thick-walled portion 5 and the first thin-walled portion 6 of the cover curved portion 5b. The second base-support curved portion 17 branches off from the other Y-direction side of the base plate portion 15 on the other Y-direction side of the base member 3 and curves so as to displace toward the other Z-direction as it approaches that side in the Y-direction. The other end face of the second base curved portion 17 in the Z direction faces a step portion of the lid curved portion 5c formed by the difference in thickness between the thick portion 5 and the second thin portion 7 of the lid curved portion 5c.

[0018] The sum of the thickness of the first base formation bending portion 16 and the thickness of the thin-walled portion 6 is approximately equal to the thickness of the thick-walled portion 5. Furthermore, the sum of the thickness of the second base formation bending portion 17 and the thickness of the thin-walled portion 7 is also approximately equal to the thickness of the thick-walled portion 5. On one side in the X direction, the base flat plate portion 15 protrudes further in the X direction than the first and second base formation bending portions 16, 17 by an X-direction length that is approximately equal to the X-direction thickness dimension of the first closure portion 8. On the other side in the X direction, the base flat plate portion 15 protrudes further in the X direction than the first and second base formation bending portions 16, 17 by an X-direction length that is approximately equal to the X-direction thickness dimension of the second closure portion 9.

[0019] The top cover member 2 is brought relatively close to the base member 3 in the Z direction, and the top cover member 2 is press-fitted and fixed to the base member 3 so that the first and second base support bending portions 16, 17 are slightly distorted inward in the Y direction. When the base member 3 and the top cover member 2 are integrated by fitting, the end face of the first base support bending portion 16 on the Z direction side of the flat cover portion 5a (the other side in the Z direction) abuts against the stepped portion of the lid curved portion 5b, and the side face on one side in the Y direction at the end on the other side in the Z direction of the first base support bending portion 16 comes into contact with the side face on the other side in the Y direction of the thin-walled portion 6, and is bent (distorted). Similarly, when the base member 3 and the upper cover member 2 are integrated by fitting together, the end face of the second base support curved portion 17 on the Z-direction side of the cover flat portion 5a (the other side in the Z-direction) abuts against the step portion of the cover curved portion 5c, and the side face on the other Y-direction at the end portion on the other Z-direction of the second base support curved portion 17 comes into contact with the side face on one side in the Y-direction of the thin-walled portion 7 and is bent (distorted).

[0020] The battery case 10 is thus constructed by integrating the base member 3 and the top cover member 2 through fitting. Because the lower surface of the base member 3 has a larger area than the upper surface of the top cover member 2, the base member 3 is suitable for use as a mounting surface for a device on which the battery case 10 is to be installed. The base member 3 and the top cover member 2 may be fixed together using a fixing means such as an adhesive or a fastening member. The battery case 10 houses a plurality of cylindrical batteries 18 and has a battery chamber 20 formed by a portion of the inner surface of the top cover member 2 mating with a portion of the inner surface of the base member 3. As shown in FIG. 3 , in the first embodiment, four batteries 18 arranged in two rows and two columns are fixed in the battery chamber 20. However, in the battery pack of the present disclosure, it is sufficient that the batteries are arranged in N rows and M columns (where N and M are both natural numbers, but at least one of N and M is an integer of 2 or greater) in the battery chamber. In addition, when multiple batteries are arranged in one example, the arrangement direction cannot be defined, but in this case, the arrangement direction may be defined as a direction perpendicular to both the height direction of the battery and the height direction of the battery pack.

[0021] The batteries 18 are fixed in the battery chamber 20, for example, by the following method. More specifically, for example, the battery housing section 40 has a battery holder 19, and the batteries 18 are fixed in the battery holder 19. Here, the battery holder 19 may have, for example, two or more arc-shaped portions 38 or annular portions arranged at both ends of each battery 18 in the X direction and spaced apart in the X direction to support most or all of the circumferential direction of the cylindrical outer circumferential surface of the battery 18, and a flat portion extending radially inward from one end of the arc-shaped portion 38 or annular portion in the X direction. The battery 18 may be held by pressing the battery 18 into the two or more arc-shaped portions 38 or two annular portions until one end face of the battery 18 contacts the flat portion. 2, when the battery holder 19 has two arc-shaped portions 38 at each end in the X direction, the arc-shaped portion 38 located on one side in the Z direction of each X direction end may be molded integrally with the base member 3, and the arc-shaped portion 38 located on the other side in the Z direction may be molded integrally with the top cover member 2. Alternatively, as is used in personal computers, multiple batteries may be fixed to predetermined positions on the inner surface of the battery housing chamber with double-sided tape or adhesive.

[0022] Although not shown, the plurality of batteries 18 are electrically connected in series and / or in parallel using bus bars or the like while arranged at predetermined positions within the battery housing chamber 20. Here, the existence of a series connection allows the output of the battery pack 1 to be increased, and the existence of a parallel connection allows the capacity of the battery pack 1 to be increased.

[0023] 4, the battery accommodating chamber 20 has an inner gas exhaust hole 21 as an inner gas exhaust portion only on the other side in the X direction. The inner gas exhaust hole 21 is an opening portion in the end face of the battery accommodating section 40, and is provided to exhaust gas generated in the battery 18 to the outside of the battery accommodating chamber 20 when the battery 18 fixed in the battery accommodating chamber 20 generates abnormal heat. A part of the top cover member 2 and a part of the base member 3 combine with each other to form the battery accommodating section 40 having the inner gas exhaust hole 21 and the battery accommodating chamber 20.

[0024] 2 and 4, the battery case 10 has a first corner passage 25a extending in the X direction at an end (corner) on one side in the Y direction at an end on the Z-direction side of the base flat plate portion 15 (one side in the Z direction), and a second corner passage 25b extending in the X direction at an end on the other side in the Y direction at the end (corner) on one side in the Z direction. As shown in Fig. 2, each of the first and second corner passages 25a, 25b is formed by combining a part of the top cover member 2 and a part of the base member 3.

[0025] Specifically, the first corner passage portion 25a is defined by the thin-walled portion 6 of the top cover member 2, the first base curved portion 16 of the base member 3, and the base flat plate portion 15 of the base member 3. The inner surface of the first corner passage portion 25a includes an inner surface portion 26 formed by a portion of the top cover member 2 and an inner surface portion 27 formed by a portion of the base member 3. Similarly, the second corner passage portion 25b is defined by the thin-walled portion 7 of the top cover member 2, the second base curved portion 17 of the base member 3, and the base flat plate portion 15 of the base member 3. The inner surface of the second corner passage portion 25b includes an inner surface portion 28 formed by a portion of the top cover member 2 and an inner surface portion 29 formed by a portion of the base member 3. The inner surface portions 26 and 28 form a first inner surface, and the inner surface portions 27 and 29 form a second inner surface.

[0026] As shown in Fig. 4, the opening of the inner gas exhaust hole 21 of the battery accommodating chamber 20 faces the second closing portion 9 at a distance on one side in the X direction, and a space 31 exists between the opening of the inner gas exhaust hole 21 and the inner surface of the second closing portion 9 on one side in the X direction. As shown in Figs. 2 and 4, the inner curved surfaces 16a, 17a of the first and second base curved portions 16, 17, which curve along the outer peripheral surface of the battery 18, define a portion of the battery accommodating chamber 20, and the outer curved surfaces 16b, 17b of the first and second base curved portions 16, 17 define a portion of the first and second corner passages 25a, 25b. This configuration makes it easier to position the battery 18 within the battery accommodating chamber 20 and effectively utilizes dead space within the battery case 10. This increases the cross section perpendicular to the extension direction of the first and second corner passages 25a, 25b, allowing for smooth gas flow. Furthermore, not only can the volumes of the first and second corner passages 25a, 25b be increased, but the battery case 10 can also be configured to be compact.

[0027] As shown in FIG. 3, each of the first and second corner passages 25a, 25b extends from one end in the X direction to the other end in the X direction. The first corner passage 25a connects to the outer gas discharge hole 2a at its other end in the X direction and communicates with the outer region of the battery pack 1. The second corner passage 25b connects to the outer gas discharge hole 2b at its other end in the X direction and communicates with the outer region of the battery pack 1. Each of the first and second corner passages 25a, 25b is a height-direction passage. The space 31 (see FIG. 4), the first corner passage 25a, and the outer gas discharge hole 2a form a gas exhaust passage 55a, and the space 31, the second corner passage 25b, and the outer gas discharge hole 2b form a gas exhaust passage 55b. The space 31 forms part of the gas exhaust passage 55a and also forms part of the gas exhaust passage 55b. As shown in FIGS. 1 and 2, the gas exhaust passages 55a and 55b are located inside the outer wall portion 50 having the outer surface 45 in contact with the outer region and outside the battery housing portion 40.

[0028] Referring to FIG. 4, suppose that at least one battery 18 generates abnormal heat and emits high-temperature gas or the like to the outside. The high-temperature gas then passes through the inner gas exhaust hole 21, which is the only part of the battery housing chamber 20 that is connected to the outside, and reaches the space 31. The gas then flows, for example, through the space 31 toward one side in the Y direction in the direction indicated by arrow B, into the first corner passage 25a, and then further flows through the first corner passage 25a toward one side in the X direction indicated by arrow C (see FIG. 3), before passing through the outer gas exhaust hole 2a and being discharged to the outside. Alternatively, the high-temperature gas that has reached the space 31 may flow through the space 31 toward the other side in the Y direction in the direction indicated by arrow D, into the second corner passage 25b, and then further flows through the second corner passage 25b toward one side in the X direction, before passing through the outer gas exhaust hole 2b and being discharged to the outside. The high-temperature gas flows a long distance from one end to the other end in the X direction (height direction of the battery 18) inside the battery case 10 after being ejected from the battery 18 and before being discharged from the outer gas discharge holes 2a, 2b. Therefore, the gas is effectively cooled by the flow from one end to the other end, and the cooled gas is released to the outside.

[0029] As described above, the battery case 10 includes a battery accommodating chamber 20 that accommodates multiple batteries 18, and a battery accommodating section 40 that has inner gas exhaust holes (inner gas exhaust portions) 21 for exhausting gas generated in the batteries 18 on at least one side in the height direction (X direction) of the batteries fixed to the battery accommodating chamber 20. The battery case 10 is also located inside an outer wall section 50 that has an outer surface 45 that contacts the outer region and outside the battery accommodating section 40, and includes first and second corner passage portions (height direction passage portions) 25a, 25b that extend along the X direction and outer gas exhaust holes (outer gas exhaust portions) 2a, 2b for exhausting gas to the outside, and one or more gas exhaust passages 55a, 55b that guide gas from the inner gas exhaust hole 21 side to the outer gas exhaust holes 2a, 2b side.

[0030] Therefore, one or more gas exhaust passages 55a, 55b for exhausting gas emitted from an abnormally heated battery 18 can be formed simply by providing a battery storage section 40 inside the battery case 10. This simplifies the structure of the battery case 10 compared to the conventional technology in which ducts are laid out outside the battery storage section, making it easier to reduce the manufacturing cost of the battery case 10.

[0031] Furthermore, the gas exhaust passages 55a, 55b have first and second corner passage portions 25a, 25b extending in the height direction (X direction) of the battery 18. Here, the dimension of the battery case 10 in the height direction (X direction) of the battery 18 tends to be long. In particular, when the batteries 18 are connected in series within the battery case 10, the X direction dimension of the battery case 10 can be made more than twice the height of the battery 18. Therefore, the length of the first and second corner passage portions 25a, 25b can be increased, and the gas can be effectively cooled while passing through the first and second corner passage portions 25a, 25b. This not only simplifies the structure of the battery case 10 and facilitates reducing the manufacturing cost of the battery case 10, but also allows the gas to be efficiently cooled, improving the cooling performance of the battery case 10.

[0032] Furthermore, the inner surfaces of the first and second corner passages 25a, 25b may include outer curved surfaces 16b, 17b that extend along the cylindrical outer peripheral surface 18a of the battery 18.

[0033] 2 and 4, this configuration allows the inner curved surfaces 16a, 17a of the first and second base curved portions 16, 17, which curve to fit the outer periphery of the battery 18, to define a portion of the battery accommodating chamber 20, while the outer curved surfaces 16b, 17b of the first and second base curved portions 16, 17 define a portion of the first and second corner passages 25a, 25b. This facilitates positioning of the battery 18 within the battery accommodating chamber 20, effectively utilizes dead space within the battery case 10, and increases the cross-section (flow path area) perpendicular to the extension direction of the first and second corner passages 25a, 25b, thereby facilitating smooth gas flow. Furthermore, not only can the volume of the first and second corner passages 25a, 25b be increased, but the battery case 10 can also be configured compactly.

[0034] The battery accommodating section 40 may also fix a plurality of batteries 18 in a double-row arrangement so that the batteries 18 are aligned in a Y direction (arrangement direction) perpendicular to the X direction. The battery case 10 may also include a first corner passage 25a located inside a first corner located on a first side in the Y direction, and a second corner passage 25b located inside a second corner located on a second side in the Y direction and facing the first corner in the Y direction. Each of the first corner passage 25a and the second corner passage 25b may be a height-direction passage extending along the X direction.

[0035] This configuration makes it possible to effectively utilize the dead space that is likely to be generated at the corners of the case, and easily form a long gas exhaust passage without increasing the size of the battery case 10, thereby enabling efficient cooling of the gas.

[0036] Alternatively, the outer gas discharge holes 2a, 2b may be present on only one side in the X direction, while the inner gas discharge hole 21 may be present on only the other side in the X direction. Alternatively, the first and second corner passages 25a, 25b may guide the gas from the other side to one side in the X direction of the battery case 10.

[0037] According to this configuration, the gas exhaust passages 55a, 55b can guide at least the gas from one side to the other side in the X direction of the battery case 10, and the path length of the gas exhaust passages 55a, 55b that cool the gas can be significantly increased, thereby enabling the gas to be cooled more efficiently.

[0038] The battery case 10 may also include a top cover member (first member) 2 and a base member (second member) 3 fixed to the top cover member 2. The inner surfaces of the first and second corner passages (height direction passages) 25a, 25b may include a first inner surface (inner surface portion 26 and inner surface portion 28) formed by a part of the top cover member 2 and a second inner surface (inner surface portion 27 and inner surface portion 29) formed by a part of the base member 3.

[0039] According to this configuration, by fixing the top cover member 2 to the base member 3, gas exhaust passages 55a, 55b can be easily formed between the top cover member 2 and the base member 3. In some cases, gas exhaust passages can also be formed between the existing case and the new member by post-fixing a new member to the existing case.

[0040] Furthermore, by adopting the fitting structure described using Figure 2 and making the area of ​​the back surface of the base plate portion 15 of the base member 3 larger than the area of ​​the top surface of the cover plate portion 5a of the top cover member 2, the area of ​​the fixing surface (the back surface) of the battery pack 1 can be easily increased, and the battery pack 1 can be securely and stably fixed to the installation location.

[0041] In the above embodiment, the one or more outer exhaust holes (through-holes) 2a, 2b serving as the outer gas exhaust section are not covered with a mesh-like material, such as a metal mesh or porous metal. However, in the battery case of the present disclosure, the outer gas exhaust section may be one or more through-holes, and the battery case may include a mesh-like material arranged to cover the through-holes. This configuration allows the gas to be cooled even with the mesh-like material, improving safety. Furthermore, the material covering the through-holes does not have to be mesh-like, and may be made of a breathable, waterproof material, such as Gore-Tex (registered trademark), that allows exhaust gas to pass through while blocking liquids such as water from the outside. The breathable, waterproof material is burned by the gas generated by the battery, and the gas is discharged to the outside of the battery pack through the outer gas exhaust section.

[0042] The present disclosure is not limited to the above-described embodiment and its modifications, and various improvements and modifications are possible within the scope of the claims of the present application and their equivalents. Some of these embodiments and modifications will be described below. In Figures 6 to 8 below, arrows indicate the flow direction of gas emitted by abnormally heated battery 18.

[0043] (Second embodiment) FIG. 5 is a perspective view of a battery pack 101 according to a second embodiment of the present disclosure. In the perspective view of FIG. 5, the internal structure of the battery pack 101 would actually need to be depicted using two-dot chain lines (imaginary lines), but is depicted using thin solid lines for clarity. In the second embodiment, the X direction coincides with the width direction (short-side direction) of the battery pack 1 (battery case 10), and the Y direction coincides with the length direction (short-side direction) of the battery pack 1 (battery case 10). In the following embodiments, including the second embodiment, the same components as those in the first embodiment are designated by the same reference numerals as those in the first embodiment, and descriptions thereof will be omitted. In the following embodiments, including the second embodiment, descriptions of the same functions, effects, and variations as those in the first embodiment will be omitted.

[0044] 5, the battery pack 101 includes a battery case 110 and a plurality of batteries 18. The battery case 110 has an outer case 120 and an inner case 130. The outer case 120 has a top plate portion 120a that extends substantially parallel to the XY plane and has a substantially rectangular upper surface, a first curved plate portion 120b that is located on one side of the top plate portion 120a in the Y direction and curves so as to displace to one side in the Z direction as it approaches that side in the Y direction, a second curved plate portion 120c that is located on the other side of the top plate portion 120a in the Y direction and curves so as to displace to one side in the Z direction as it approaches the other side in the Y direction, a first side plate portion 120d that extends substantially parallel to the XZ plane from an end on one side in the Z direction of the first curved plate portion 120b, and a second side plate portion 120e that extends substantially parallel to the XZ plane from an end on one side in the Z direction of the second curved plate portion 120c.

[0045] The outer case 120 also has a bottom plate 120f that is connected to one end of the first side plate 120d in the Z direction and one end of the second side plate 120e in the Z direction, extends substantially parallel to the top plate 120a, and has a substantially rectangular bottom surface. The outer case 120 also has a first lid 120g that is connected to one end of the plate portions 120a to 120f in the X direction and closes the opening of the outer case 120 on one side in the X direction, and a second lid 120h that is connected to the other end of the plate portions 120a to 120f in the X direction and closes the opening of the outer case 120 on the other side in the X direction.

[0046] The inner case 130 is disposed within the outer case 120. In the second embodiment, the batteries 18 are arranged in a single row and multiple columns. The inner case 130 has a structure in which a plurality of cylinders (bottomed cylinders) 131 are arranged in multiple columns in the Y direction (arrangement direction), and every pair of two adjacent cylinders 131 in the Y direction is connected. One battery 18 is housed in each cylinder 131. The inner case 130 is fixed within the outer case 120 by, for example, press fitting, shrink fitting, or cold fitting. The outer case 120 has, for example, a stopper (not shown) on one side in the X direction that protrudes inward from the inner surface of the outer case 120 and expands in the YZ directions. The inner case 130 is fixed to the outer case 120 by pushing the inner case 130 toward one side in the X direction until it contacts the stopper.

[0047] 5, when the inner case 130 is fixed at a predetermined position within the outer case 120 and integrated with the outer case 120, one end of each cylinder 131 in the Z direction contacts the bottom plate portion 120f, and the other end of each cylinder 131 in the Z direction contacts the top plate portion 120a. Each of the first and second curved plate portions 120b, 120c has a curved shape corresponding to a circumferential portion of the cylindrical outer peripheral surface of the cylinder 131 (a portion approximately corresponding to π / 2 in the circumferential direction). In this integrated state, the inner surface of the first curved plate portion 120b contacts a circumferential portion of the cylindrical outer peripheral surface 131a of the cylinder 131 located at the end on one side in the Y direction, and the inner surface of the second curved plate portion 120c contacts a circumferential portion of the cylindrical outer peripheral surface 131b of the cylinder 131 located at the end on the other side in the Y direction. This allows the inner case 130 to be precisely positioned at a predetermined position on the outer case 120 in this integrated state.

[0048] Each cylinder 131 has a generally cylindrical shape with a bottom, and has an opening that allows gas to be effectively discharged only to the other side in the X direction. The opening on the other side in the X direction of each cylinder 131 constitutes an inner gas discharge hole 121 included in the inner gas discharge section. The opening of the inner gas discharge hole 121 is positioned at a distance in the X direction from the inner surface on one axial side of the second cover portion 120h, and a space 141 exists between the opening of the inner gas discharge hole 121 and the inner surface on one axial side of the second cover portion 120h.

[0049] 5, in the integrated state, the battery case 110 has a first corner passage 171 and a second corner passage 172 that are located at both Y-direction ends on one side in the Z direction between the outer case 120 and the inner case 130 and extend in the X direction. Furthermore, with respect to the region on one side in the Z direction, the battery case 110 has central passages 181, 182, 183 that extend in the X direction in a Y-direction range between a Y-direction position where one of two cylinders 131 adjacent in the Y direction contacts the bottom plate portion 120f and a Y-direction position where the other of the two cylinders 131 contacts the bottom plate portion 120f.

[0050] In addition, with respect to the region on the other side of the Z direction, the battery case 110 has central passage portions 191, 192, 193 extending in the X direction in the Y direction range between the Y direction position where one of two adjacent cylinders 131 in the Y direction contacts the top plate portion 120a and the Y direction position where the other of the two cylinders 131 contacts the top plate portion 120a.

[0051] Although not shown, each of the first lid portions 120g facing each of the passage portions 171, 172, 181-183, and 191-193 has an outer gas exhaust hole extending in the X direction. These outer gas exhaust holes form an outer gas exhaust section. This allows gas flowing through each of the passage portions 171, 172, 181-183, and 191-193 on one side in the X direction to be exhausted to the outside of the battery case 110 through the outer gas exhaust hole.

[0052] As described above, in the battery case 110, the battery housing portion 140 may be configured to fix the batteries 18 in a state in which the batteries 18 are arranged in multiple rows in the Y direction perpendicular to the X direction. The battery case 110 may also include central passages 181-183, 191-193 located between first-side ends of the batteries 18 belonging to a first row located on a first side in the Y direction of two rows adjacent to each other in the Y direction and second-side ends of the batteries 18 belonging to a second row located on a second side in the Y direction of the two rows. The central passages 181-183, 191-193 may be height-direction passages extending along the X direction.

[0053] According to this configuration, with respect to each of the central passage portions 181-183, 191-193 of the battery case 110, not only can a partial region (approximately half of the region) of the central passage portions 181-183, 191-193 be formed between one of two batteries 18 adjacent in the Y direction and the Z-direction end face of the battery case 110, but another partial region (approximately the remaining half of the region) of the central passage portions 181-183, 191-193 can also be formed between the other battery 18 and the Z-direction end face of the battery case 110. Therefore, the flow path areas (cross-sectional areas when the passage portions are cut in the YX plane) of the central passage portions 181-183, 191-193 are larger than the flow path areas of the corner passage portions 171, 172, and the amount of gas flowing through the central passage portions 181-183, 191-193 can be larger than the amount of gas flowing through the corner passage portions 171, 172. Therefore, the gas cooling effect of the central passage portions 181-183 and 191-193 is greater than the gas cooling effect of the corner passage portions 171 and 172, so the cooling effect of the battery case 110 can be significantly increased.

[0054] The battery case 110 may also include an inner case 130 having a battery housing portion 140 and an outer case 120 that houses the inner case 130. The gas exhaust passage may be defined by the outer surface of the inner case 130 and the inner surface of the outer case 120.

[0055] According to this configuration, the gas exhaust passage can be easily formed simply by fixing the inner case 130 into the outer case 120 by press fitting, shrink fitting, cold fitting, or the like.

[0056] As shown in FIG. 5, when each of the central passage sections 181-183, 191-193 has two arc-shaped sections 188 that define a portion thereof, and when there is a plane (not shown) that is approximately symmetrical to the two arc-shaped sections 188, the capacity of the battery accommodating chamber 155 can be reduced and the positioning of the battery 18 in the battery accommodating chamber 155 can be easily performed. In addition, the flow path area of ​​the central passage sections 181-183, 191-193 can be increased, and further, the battery case 110 can be configured more compactly.

[0057] 5, first protruding plate portions 167 that protrude from one side in the Y direction to the other side in the Y direction and block part of the flow path area and second protruding plate portions 168 that protrude from the other side in the Y direction to one side in the Y direction and block part of the flow path area may be alternately arranged at intervals in the X direction within the passage of at least one of the central passage portions 191-193. By adopting this configuration, the path length along which gas flows in the central passage portions 191-193 can be increased, and the gas cooling performance in the central passage portions 191-193 can be improved.

[0058] (Third embodiment) In the first embodiment, each corner passage portion (height-direction passage portion) 2a, 2b is connected to one outer gas discharge hole 2a, 2b, and each gas exhaust passage 55a, 55b has one outer gas discharge hole 2a, 2b. However, even if the battery case has multiple height-direction passage portions, the battery case may have only one outer discharge hole. Furthermore, at least one gas exhaust passage may have a passage portion other than a height-direction passage portion extending in the height direction. For example, in addition to a height-direction passage portion, it may include an arrangement-direction passage extending in the arrangement direction.

[0059] 6, that is, a schematic cross-sectional view of a battery pack 201 of the third embodiment corresponding to the schematic cross-sectional view taken along line E-E in FIG. 1, the battery case 210 may have first and second corner passage portions 25a, 25b, and only one outer discharge hole 202 may be provided in the center in the Y direction of an end face 278 on one side in the Z direction of the battery case 210. In this way, the path length of each gas exhaust passage 255a, 255b can be increased by approximately half the path length of the parallel-direction passages 28a, 28b, i.e., the length indicated by arrow F, of the battery case 210 in the end region on one side in the Z direction where gas is exhausted to the outside, thereby improving the cooling effect of each gas exhaust passage 255a, 255b.

[0060] (Fourth embodiment) In the second embodiment, the first and second protruding plate portions 167, 168 are provided in the height direction passage portions (central passage portions 191 to 193) to increase the path length of the height direction passage portions (central passage portions 191 to 193). Here, such first and second protruding plate portions may also serve to rectify the flow of gas.

[0061] 7, i.e., a schematic cross-sectional view of a battery pack 301 according to the fourth embodiment corresponding to FIG. 6, the gas flow direction is defined as the direction in which gas flows from the inner gas discharge holes 321 to the outer gas discharge holes 302 in the height-direction passages 355a, 355b. In this case, first protruding plate portions 367 protruding from one side in the Y direction to the other side in the Y direction and second protruding plate portions 368 protruding from the other side in the Y direction to the other side in the Y direction may be alternately configured at intervals in the X direction in at least one of the height-direction passages 355a, 355b. Each of the protruding plate portions 367, 368 may protrude in a direction inclined in the X direction so that the distal end is positioned downstream in the gas flow direction. By adopting such a configuration, not only can the path length of the vertical passage sections 355a, 355b be increased, but each of the protruding plate sections 367, 368 does not obstruct the flow of gas downstream, and the gas can flow smoothly downstream while being rectified by each of the protruding plate sections 367, 368.

[0062] (Fifth embodiment) In the first embodiment, the corner passage portions (height direction passage portions) 25a, 25b extend from one end to the other end in the X direction of the battery case 10. However, the height direction passage portions do not have to extend from one end to the other end in the X direction of the battery case.

[0063] 8, that is, a schematic cross-sectional view of a battery pack 401 according to the fifth embodiment corresponding to FIG. 6, inner gas exhaust holes 421, 422 as an example of an inner gas exhaust portion may be located on both sides in the height direction (X direction) of the battery 18 in the battery accommodating portion 440. One or more outer gas exhaust holes 402, 403 as an example of an outer gas exhaust portion may be located in the center of the battery case 410 other than at both ends in the X direction.

[0064] Depending on the specifications of the battery pack, a large number of batteries 18 may be connected in series, resulting in a long height dimension of the batteries 18 in the battery pack. In such a case, even if the configuration of the fifth embodiment is adopted, it is possible to form a gas guide passage having a path length sufficient for cooling the gas.

[0065] (Other variations) In the first embodiment, the upper cover member 2 is fixed (more specifically, fixed by engagement) to the base member 3, and the inner surfaces of the corner passage portions (height-wise passage portions) 25a, 25b include a first inner surface (inner surface portion 26 and inner surface portion 28) formed as part of the upper cover member 2, and a second inner surface (inner surface portion 27 and inner surface portion 29) formed as part of the base member 3.

[0066] However, the height-direction passage may be formed only by the inner surface of a single member. For example, the height-direction passage in the battery case may be formed by extrusion molding using a resin material or a metal material. In this case, the height-direction passage can be formed only by the inner surface of a single member.

[0067] In the battery case of the present disclosure, when an inner gas vent hole is provided at the end in the X direction, the inner gas vent hole may be provided on the outer peripheral surface of the battery housing section, and when an outer gas vent hole is provided at the end in the X direction, the outer gas vent hole may be provided on the outer peripheral surface of the battery case.

[0068] Furthermore, in the battery case of the present disclosure, the inner gas exhaust portion does not have to be an inner gas exhaust hole, and the outer gas exhaust portion does not have to be an outer gas exhaust hole. More specifically, for safety reasons, conventionally, secondary batteries have a structure that breaks when the internal pressure exceeds a predetermined pressure, allowing the generated gas and the like to be discharged to the outside. Similarly, at least one of the inner gas exhaust portion and the outer gas exhaust portion may have a structure that breaks when the internal pressure exceeds a predetermined pressure, and such a structure may be, for example, a portion that has lower strength (rigidity) than other portions.

[0069] In addition, in the battery case of the present disclosure, the height-direction passage portion does not have to have an inner surface formed of a curved surface. In addition, the battery case of the present disclosure may have only one corner passage portion, or may have no corner passage portions. In addition, the outer shape of the battery case of the present disclosure does not have to be the semi-cylindrical shape shown in FIG. 1 and may be any shape, such as a rectangular parallelepiped or a cylindrical shape. [Explanation of symbols]

[0070] 1,101,201,301,401 Battery pack, 2 Top cover member, 2a,2b,202,302,402 Outer gas exhaust hole, 3 Base member, 10,110,210,410 Battery case, 16 First base curved portion, 16a Inner curved surface, 16b Outer curved surface, 17 Second base curved portion, 18 Battery, 20 Battery storage chamber, 21,121,321,421 Inner gas exhaust hole, 25a,171 First corner passage portion, 25b,172 Second corner passage portion, 40,140 Battery storage portion, 45 Outer surface, 50 Outer wall portion, 55a,55b,255a,255b Gas exhaust passage, 120 Outer case, 130 Inner case, 155 battery compartment, 181-183, 191-193 central passage sections, 355a, 355b vertical passage sections.

Claims

1. a battery accommodating section having a battery accommodating chamber that accommodates a plurality of cylindrical batteries and an inner gas exhaust section on at least one side in the height direction of the cylindrical batteries fixed to the battery accommodating chamber for exhausting gas generated in the cylindrical batteries; one or more gas exhaust passages that are located inside an outer wall portion having an outer surface in contact with the outer region and outside the battery accommodating portion, and that have a height direction passage portion that extends along the height direction and an outer gas exhaust portion that exhausts the gas to the outside, and that guide the gas from the inner gas exhaust portion side to the outer gas exhaust portion side; a base member having a base flat plate portion and a base branch portion branching from the base flat plate portion; a top cover member that is fitted together with the base member, the battery accommodating section is configured to fix the plurality of cylindrical batteries in a state in which the batteries are arranged in multiple rows in an arrangement direction perpendicular to the height direction, the first corner passage is located on the inside of a first corner located on a first side in the arrangement direction, and the second corner passage is located on the inside of a second corner located on a second side in the arrangement direction and facing the first corner in the arrangement direction, At least one of the first corner passage portion and the second corner passage portion is the height direction passage portion, The height-direction passage portion includes a part of the top cover member, the base branch portion, and the base member.

2. the battery accommodating section has a battery holder that fixes the plurality of cylindrical batteries; the battery accommodating section is configured to fix the plurality of cylindrical batteries in a state in which the batteries are arranged in multiple rows in an arrangement direction perpendicular to the height direction, The battery case according to claim 1 , wherein the height-direction passage and the battery holder overlap when viewed from a direction perpendicular to the height direction and the arrangement direction.

3. In a state where the base member and the top cover member are integrated by fitting, The battery case according to claim 1 , wherein an end face of the base branch portion in the height direction of the battery case abuts against the top cover member, and a side face of the base branch portion contacts an inner surface of the top cover member.

4. The base branch portion is Extending along the cylindrical outer peripheral surface of the cylindrical battery, The battery case according to claim 1 .

5. The battery case according to claim 1 , wherein the height-direction passage portion is defined by a part of the top cover member, the base branch portion, and the base member.

6. a central passage portion located between, in the arrangement direction, an end of the first side of the cylindrical batteries belonging to a first row located on a first side in the arrangement direction among two rows adjacent to each other in the arrangement direction, and an end of the second side of the cylindrical batteries belonging to a second row located on a second side in the arrangement direction among the two rows; The battery case according to claim 1 , wherein the central passage portion is the height-direction passage portion.

7. the inner gas exhaust section is located on both sides of the battery accommodating section in the height direction, The battery case according to claim 1 , wherein the outer gas discharge portion is located at a center portion other than both end portions in the height direction.

8. an inner case having the battery housing portion; an outer case that houses the inner case; the outer gas exhaust portion is one or more through holes, 2. The battery case of claim 1, further comprising a mesh-like member arranged to cover the through-hole, or a breathable and waterproof member that is made of a breathable and waterproof material that allows the gas to pass through while preventing external water from penetrating into the outer case, and that covers the through-hole.

9. a battery accommodating section having a battery accommodating chamber that accommodates a plurality of cylindrical batteries and an inner gas exhaust section on at least one side in the height direction of the cylindrical batteries fixed to the battery accommodating chamber for exhausting gas generated in the cylindrical batteries; one or more gas exhaust passages that are located inside an outer wall portion having an outer surface in contact with the outer region and outside the battery accommodating portion, and that have a height direction passage portion that extends along the height direction and an outer gas exhaust portion that exhausts the gas to the outside, and that guide the gas from the inner gas exhaust portion side to the outer gas exhaust portion side; a base member having a base flat portion and a base curved portion branching from the base flat portion and extending along the cylindrical outer peripheral surface of the cylindrical battery; a top cover member that is fitted together with the base member, the battery accommodating section is configured to fix the plurality of cylindrical batteries in a state in which the batteries are arranged in multiple rows in an arrangement direction perpendicular to the height direction, a first corner passage portion located inside a first corner portion located on a first side in the arrangement direction; a second corner passage portion located on a second side in the arrangement direction and inside a second corner portion opposite the first corner portion in the arrangement direction, each of the first corner passage portion and the second corner passage portion is the height direction passage portion, The height-direction passage portion is defined by a part of the top cover member, the base curved portion, and the base member.

10. the battery accommodating section has a battery holder that fixes the plurality of cylindrical batteries; The battery accommodating section is configured to arrange the plurality of cylindrical batteries in an arrangement direction perpendicular to the height direction. The rollers are fixed in a double row arrangement as shown below. The plurality of cylindrical batteries include a first cylindrical battery located at the first corner and a second cylindrical battery located at the second corner. and a second cylindrical battery located at When viewed from a direction perpendicular to the height direction and the arrangement direction, the height direction passage portion and the front 10. The battery case of claim 9, wherein the battery holders overlap.

11. a battery accommodating section having a battery accommodating chamber that accommodates a plurality of cylindrical batteries and an inner gas exhaust section on at least one side in the height direction of the cylindrical batteries fixed to the battery accommodating chamber for exhausting gas generated in the cylindrical batteries; a height-direction passage portion that is located inside an outer wall portion having an outer surface that contacts the outer region and outside the battery accommodating portion, and that extends along the height direction; and one or more gas exhaust passages that have an outer gas exhaust portion for exhausting the gas to the outside, and that guide the gas from the inner gas exhaust portion side to the outer gas exhaust portion side, the battery accommodating section has a battery holder that fixes the plurality of cylindrical batteries; the battery accommodating section is configured to fix the plurality of cylindrical batteries in a state in which the batteries are arranged in multiple rows in an arrangement direction perpendicular to the height direction, When viewed from a direction perpendicular to the height direction and the arrangement direction, the height direction passage and the battery holder overlap, the outer gas discharge portion is present on only one side in the height direction, while the inner gas discharge portion is present on only the other side in the height direction; A battery case in which, regardless of which of the cylindrical batteries the gas is generated in, the generated gas is guided from the other end to the one end in the height direction by the height-direction passage portion.

12. A battery case according to any one of claims 1 to 11; a plurality of cylindrical batteries disposed in the battery accommodating chamber of the battery case.

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