Battery pack

Abstract

Provided is a battery pack having improved adhesion to a cylindrical battery cell. A battery pack 100 according to the present disclosure is provided with a battery case 1 provided with a plurality of housing parts 11 for housing one cylindrical battery cell 10, the housing parts 11 being arranged side by side in one direction, the housing parts 11 having wall parts 12 that define a space for housing the cylindrical battery cell 10, and the wall parts 12 being arranged in the housing part 11. The wall part (12) in a state before the cylindrical battery cell (10) is accommodated defines an elliptical cylindrical space, a slit (13) is provided in the wall part (12) parallel to the central axis (C) of the elliptical cylindrical space, the direction in which the accommodating parts (11) are arranged in one direction is the long axis direction of the elliptical cylindrical space, and the direction perpendicular to the long axis direction is the short axis direction. The direction perpendicular to the long axis direction and the short axis direction and parallel to the center axis C of the elliptical cylindrical space is set as the depth direction, and the longest short axis diameter L2 in the short axis direction of the elliptical cylindrical space in the accommodating part 11 is less than the diameter of the cylindrical battery cell 10.

Description

Technical Field

[0001] The present disclosure relates to a battery pack. Background Art

[0002] Patent Document 1 describes a battery holder that holds a plurality of cylindrical batteries in an aligned state. The battery holder has a plurality of cylindrical battery accommodation portions that respectively accommodate the batteries, and each battery accommodation portion is formed of a substantially cylindrical wall portion having elasticity that can expand in diameter when a battery is inserted.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2016-207569 Summary of the Invention

[0006] Technical Problem to be Solved by the Invention

[0007] It is technically known that cylindrical batteries have dimensional tolerances in their sizes. For example, when the diameter of a cylindrical battery accommodated in a battery holder is at the maximum value of the dimensional tolerance, the cylindrical battery can be appropriately accommodated in the battery accommodation portion by expanding the diameter of the battery accommodation portion. However, when the diameter of the cylindrical battery accommodated in the battery holder is at the minimum value of the dimensional tolerance, since there is no expansion of the diameter of the battery accommodation portion, the tightness between the cylindrical battery and the battery accommodation portion is reduced, and thus there is a concern that the cylindrical battery cannot be appropriately accommodated in the battery holder.

[0008] Therefore, the main object of the present disclosure is to provide a battery pack with improved tightness to a cylindrical battery core.

[0009] Technical Solution for Solving the Technical Problem

[0010] The battery pack according to the present disclosure is as follows:

[0011] A battery pack including a battery case having a plurality of accommodation portions for accommodating one cylindrical battery core, the accommodation portions being arranged in one direction,

[0012] The accommodation portion has a wall portion that defines a space for accommodating the cylindrical battery core,

[0013] The wall portion defines an elliptical cylinder-shaped space in a state before accommodating the cylindrical battery core,

[0014] A slit is provided in the wall portion parallel to the central axis of the elliptical cylinder-shaped space.

[0015] The direction in which the accommodating portions are arranged in one direction is set as the major axis direction of the elliptical cylinder-shaped space, the direction perpendicular to the major axis direction is set as the minor axis direction, and the direction perpendicular to both the major axis direction and the minor axis direction and parallel to the central axis of the elliptical cylinder-shaped space is set as the depth direction. The longest minor axis diameter in the minor axis direction of the elliptical cylinder-shaped space in the accommodating portion is equal to or less than the diameter of the cylindrical battery core.

[0016] Advantages of the Invention

[0017] According to the battery pack of the present disclosure, a battery pack with improved adhesion to the cylindrical battery core can be provided. Specifically, since a slit is provided parallel to the central axis of the elliptical cylinder-shaped space in the wall portion defining the elliptical-shaped extending space, the adhesion between the wall portion and the outer peripheral surface of the cylindrical battery core can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 FIG. is a perspective view schematically showing a first embodiment of the battery pack of the present disclosure.

[0019] Figure 2 FIG. is a front view of the battery housing in the first embodiment as viewed from the axial direction.

[0020] Figure 3 FIG. is a front view of the battery housing in a modification of the first embodiment as viewed from the axial direction.

[0021] Figure 4 FIG. is a perspective view schematically showing a second embodiment of the battery pack of the present disclosure.

[0022] Figure 5 FIG. is a front view of the battery housing in the second embodiment as viewed from the axial direction.

[0023] Figure 6 FIG. is a perspective view schematically showing a third embodiment of the battery pack of the present disclosure.

[0024] Figure 7 FIG. is a front view of the battery housing in the third embodiment as viewed from the axial direction. DETAILED DESCRIPTION OF THE INVENTION

[0025] Hereinafter, a battery pack according to an embodiment of the present disclosure will be described in more detail. If necessary, reference will be made to the accompanying drawings. However, the various elements in the drawings are merely schematically and exemplarily shown for understanding the present disclosure, and the appearance, dimensional ratios, etc. may be different from the actual objects.

[0026] In this specification, unless specifically stated with terms such as "less than", "more / greater", etc., various numerical ranges mentioned are intended to include the numerical values of the lower and upper limits themselves. That is to say, for example, taking a numerical range of 1 to 10 as an example, it can be interpreted as including the lower limit value "1" and also including the upper limit value "10". In addition, terms such as "about" and "around" mean that a variation of a few percent, such as ±10%, can be included.

[0027] As used in this specification, "top view observation" refers to the state when the object to be placed (e.g., a battery pack) is placed and observed from directly above in the thickness (height) direction, which is synonymous with the top view. As an example, the top view observation is the state when observing along the negative direction in the Figure 1 "minor axis direction" shown. Unless otherwise specified, as used in this specification, "side view observation" refers to the state when the object to be placed (e.g., a battery pack) is placed and observed from the side perpendicular to its thickness (height) direction, which is synonymous with the side view. As an example, the side view observation is the state when observing along the negative direction (or positive direction) in the Figure 1 "major axis direction" shown. Unless otherwise specified, as used in this specification, "front view observation" refers to the state when the object to be placed (e.g., a battery pack) is placed and observed from the front perpendicular to its thickness (height) direction, which is synonymous with the front view. As an example, the front view observation is the state when observing along the negative direction in the Figure 1 "depth direction" shown. It should be noted that the above-mentioned "positive direction" means Figures 1 to 7 the direction of the arrow in the major axis direction, minor axis direction, and depth direction shown, and the "negative direction" means the direction opposite to the Figures 1 to 7 direction of the arrow in the major axis direction, minor axis direction, and depth direction shown.

[0028] The first embodiment of the battery pack of the present disclosure

[0029] Refer to Figures 1 to 3 to describe the first embodiment of the battery pack of the present disclosure. The battery pack 100 of the present disclosure includes a battery housing 1 as a main component (refer to Figure 1 ). In addition, as secondary components, it may include a cylindrical battery cell 10 housed in the battery housing 1, a tab 20 electrically connecting the housed cylindrical battery cell 10, and an outer packaging member 30 housing the battery housing 1. Hereinafter, the components of the battery pack 100 of the present disclosure will be specifically described.

[0030] Battery housing

[0031] The battery housing 1 includes a plurality of accommodation portions 11 for accommodating one cylindrical battery cell 10. In Figure 2 showing an example, the number of the accommodation portions 11 is five, but as long as it is two or more, the number of the accommodation portions 11 is not limited to the above example. As an example, asFigure 3 As shown, the number of the accommodating portions 11 may also be two. In addition, the accommodating portions 11 are arranged in one direction. It should be noted that, in this specification, the direction in which the accommodating portions 11 are arranged is defined as the major axis direction, and the direction perpendicular to the major axis direction is defined as the minor axis direction. In addition, the direction perpendicular to the major axis direction and the minor axis direction and parallel to the central axis of the cylindrical battery core 10 is defined as the depth direction.

[0032] The accommodating portion 11 has a wall portion 12 that defines a space for accommodating the cylindrical battery core 10. And, this space is elliptical in a front view before accommodating the cylindrical battery core 10. It should be noted that, after accommodating the cylindrical battery core 10, this space is not limited to an elliptical shape because the wall portion 12 is deformed by the cylindrical battery core 10. In an example shown Figure 2 the elliptical accommodating portion 11 has a major axis diameter L1 and a minor axis diameter L2. It should be noted that the "major axis diameter L1" as described in this specification is synonymous with the longest length of the elliptical accommodating portion 11 in the major axis direction before accommodating the cylindrical battery core 10, and the "minor axis diameter L2" is synonymous with the longest length of the elliptical accommodating portion 11 in the minor axis direction before accommodating the cylindrical battery core 10. It should be noted that the major axis diameter L1 is configured to be longer than the minor axis diameter L2.

[0033] The wall portions 12 of adjacent accommodating portions 11 may be connected to each other. In other words, the wall portion 12 can be integrated as one component. By designing the wall portion 12 in this way, the handling of the wall portion 12 can be made easier.

[0034] In the wall portion 12, a slit 13 is provided parallel to the central axis C of the elliptical cylinder-shaped space. It should be noted that the "central axis of the elliptical cylinder-shaped space" as described in this specification refers to an axis that passes through the center of the elliptical cylinder-shaped space and extends parallel to the above-mentioned depth direction. That is, the slit 13 is provided parallel to the depth direction. As long as the material of the wall portion 12 is a component that can be elastically deformed, any material can be used, but a resin material is preferably used. In addition, as the material properties of the resin material, it is preferably satisfied that any one of the tensile strength is 15 MPa or more, the bending strength is 15 MPa or more, or the flexural modulus of elasticity is 4000 MPa or less. Thus, the wall portion 12 provided with the slit 13 can be elastically deformed in the minor axis direction when the cylindrical battery core 10 is accommodated in the accommodating portion 11.

[0035] Here, as a characteristic element of the battery pack 100 of the present disclosure, it can be cited that the minor axis diameter L2 of the elliptical cylinder-shaped space provided in the accommodating portion 11 is equal to or less than the diameter of the cylindrical battery core 10.

[0036] It should be noted that the "diameter of the cylindrical battery cell 10" mentioned in this specification refers to a concept of the diameter dimension that not only includes the diameter of the cylindrical battery cell 10 as shown literally, but also includes the minimum value of the dimensional tolerance of the cylindrical battery cell 10. It should be noted that the dimensional tolerance mentioned in this specification means a difference of ±2% of the diameter of the cylindrical battery cell 10.

[0037] According to the battery pack 100 of the present disclosure, when the cylindrical battery cell 10 is housed in the housing portion 11, the wall portion 12 elastically deforms in such a manner that the gap of the slit 13 becomes wider. Then, since the minor axis diameter L2 of the elliptical cylinder-shaped space is equal to or less than the diameter of the cylindrical battery cell 10, the elliptical cylinder-shaped space elastically deforms in the minor axis direction. Then, an elastic force caused by the elastic deformation is generated in the minor axis direction, and thus the cylindrical battery cell is clamped by the wall portion 12 in the minor axis direction. Therefore, the wall portion 12 after elastic deformation can be properly fitted to the outer peripheral surface of the cylindrical battery cell 10.

[0038] As a suitable solution for the housing portion 11, the major axis diameter L1 of the elliptical cylinder-shaped space can be a length equal to or greater than the diameter of the cylindrical battery cell 10. By setting the major axis diameter L1 of the elliptical cylinder-shaped space as described above, even when the cylindrical battery cell 10 is housed in the battery case 1, elastic deformation of the housing portion 11 in the direction of arrangement in one direction (major axis direction) can be prevented. That is, even when one cylindrical battery cell 10 is housed in the housing portion 11 and other cylindrical battery cells 10 are housed in the housing portion 11 adjacent to the housing portion 11, since the major axis diameter L1 is equal to or greater than the diameter of the cylindrical battery cell 10, elastic deformation of the housing portion 11 in the major axis direction is suppressed. As a result, the distance between the central axis of one cylindrical battery cell 10 and the central axis of other cylindrical battery cells 10 is not likely to change, and the distance between the central axis of one cylindrical battery cell 10 and the central axis of other cylindrical battery cells 10 can be maintained constant. It should be noted that the "central axis of the cylindrical battery cell" refers to an axis that passes through the center of the cylindrical battery cell 10 and extends parallel to the above-mentioned depth direction.

[0039] In addition, as a suitable solution for the accommodating portion 11, when the cylindrical battery cell 10 is accommodated in an elliptical cylinder-shaped space, the central axis C of the elliptical cylinder-shaped space may coincide with the central axis of the cylindrical battery cell 10. Further, in the major axis direction of the elliptical cylinder-shaped space, as described above, the major axis diameter L1 of the space is a length greater than or equal to the diameter of the cylindrical battery cell 10. Thus, even when one cylindrical battery cell 10 is accommodated in the accommodating portion 11 and other cylindrical battery cells 10 are accommodated in the accommodating portion 11 adjacent to this accommodating portion 11, the central axis C of the elliptical cylinder-shaped space coincides with the central axis of the cylindrical battery cell 10. Furthermore, the distance between the central axis of one cylindrical battery cell 10 and other adjacent cylindrical battery cells 10 is less likely to change, and thus the positioning between the tabs 20 described below can be easily performed.

[0040] In addition, as a suitable solution for the accommodating portion 11, the length in the depth direction of the accommodating portion 11 may be greater than or equal to the length in the depth direction of the cylindrical battery cell 10. By designing the length in the central axis direction of the accommodating portion 11 in this way, the contact area between the cylindrical battery cell 10 accommodated in the accommodating portion 11 and the wall portion 12 of the accommodating portion 11 increases, and an improvement in heat transfer efficiency can be achieved.

[0041] In addition, in Figure 2 the present embodiment shown, the slit 13 is provided in the boundary region A between the adjacent accommodating portions 11. The "boundary region" as referred to in this specification means the boundary position Ap between the adjacent accommodating portions 11 and the region within the range of ±10% of the length ΔA from the boundary position Ap to the major axis diameter L1. In Figure 2 the present embodiment shown, in the accommodating portions 11 other than the central accommodating portion 11, the slit 13 is provided in the boundary region A between the adjacent accommodating portions 11, and thus the entire region above the cylindrical battery cell 10 can be covered by the wall portion 12. Therefore, by providing the slit 13 in the above-mentioned boundary region A, the cylindrical battery cell 10 can be properly fitted to the wall portion 12.

[0042] In addition, in Figure 2 the present embodiment shown, the slit 13 provided in the central accommodating portion 11 is provided at a position overlapping with the central axis C of the accommodating portion 11 when the battery housing 1 is viewed from above. It should be noted that, as described above, viewing from above means the state when viewed along the negative direction in the minor axis direction shown in Figure 1 the present embodiment. When the slit 13 is provided in this way, the cylindrical battery cell 10 can be easily accommodated in the central accommodating portion 11.

[0043] In addition, in Figure 2In the embodiment shown, the slits 13 formed in the plurality of receiving portions 11 are plane-symmetrical with respect to a bisecting plane P of the battery case 1 parallel to the minor axis diameter L2 of the elliptical cylindrical space. The "bisecting plane" referred to in this specification means a plane that includes a length D (see FIG. 1 ) parallel to the major axis direction in the battery case 1. Figure 2 ) is a plane that is perpendicular to the long axis direction of the battery case 1 and is also a plane that is perpendicular to the plane of the perpendicular bisector that bisects the battery case 1. In addition, the plane symmetry mentioned in this specification means that the shapes of the object divided into two parts when cut along the bisecting plane P are substantially the same shape. In this way, when the slit 13 is arranged in a plane-symmetrical manner, the elastic deformation caused by the wall portion 12 is symmetrical in the direction in which the receiving portion 11 is arranged, so the closeness of the wall portion 12 and the cylindrical battery core 10 is further improved. Therefore, it is easy to transfer the heat generated from the cylindrical battery core 10 to the battery case 1, and the heat dissipation of the cylindrical battery core 10 can be further improved.

[0044] In addition, Figure 2 In the embodiment shown, the slits 13 provided in the plurality of housing portions 11 are provided at positions higher than the major axis diameter L1 of the ellipse in front view ( Figure 2 In other words, the slit 13 is located on the same direction side (upper side) as the positive direction of the short axis direction. By providing the slit 13 in this way, the elastic deformation caused by the wall portion 12 can be aligned in the same direction side, and appropriate elastic deformation can be generated.

[0045] In addition, Figure 2 In the present embodiment shown, the short axis diameter L2 is preferably a length of 90% or more of the diameter of the cylindrical battery core 10 accommodated in the accommodating portion 11. More preferably, it is preferably a length of 100% or less of the diameter of the cylindrical battery core 10 accommodated in the accommodating portion 11. By making the short axis diameter L2 as above, the following effects are achieved. The accommodating portion 11 has a slit 13, and the short axis diameter L2 is the above length. Thus, when the cylindrical battery core 10 is accommodated, the accommodating portion 11 (wall portion 12) can be elastically deformed in a manner that the space accommodating the cylindrical battery core 10 is expanded to a degree that it does not rupture. Thus, when the cylindrical battery core 10 is accommodated in the accommodating portion 11, the battery case 1 (wall portion 12) can be prevented from rupturing.

[0046] In addition, by making the minor-axis diameter L2 as described above, the contact area between the wall portion 12 and the surface of the cylindrical battery core 10 can be increased. First, as a comparative example, a case where the minor-axis diameter L2 is less than 90% of the diameter of the cylindrical battery core 10 accommodated in the accommodating portion 11 will be described. In this case, when the cylindrical battery core 10 is accommodated in the accommodating portion 11, the width (length in the major-axis direction) of the slit 13 expands further compared to the present embodiment. In other words, the area where the wall portion 12 contacts the cylindrical battery core 10 becomes smaller. As a result, the heat generated from the cylindrical battery core 10 is difficult to transfer to the battery case 1.

[0047] In contrast, in the present embodiment, by making the minor-axis diameter L2 as described above, the expansion of the width (length in the major-axis direction) of the slit 13 when the cylindrical battery core 10 is accommodated in the accommodating portion 11 can be minimized. That is, compared to the comparative example, the contact area between the wall portion 12 and the surface of the cylindrical battery core 10 can be increased. As a result, it is easy to transfer the heat generated from the cylindrical battery core 10 to the battery case 1, and the heat dissipation performance of the cylindrical battery core 10 can be further improved.

[0048] Cylindrical battery core

[0049] The cylindrical battery core 10, which is a secondary component of the present disclosure, is accommodated in the accommodating portion 11 of the battery case 1 described above. The cylindrical battery core 10 is intended to be a chemical battery that mainly converts chemical energy into direct current power through a chemical reaction, but it can also be a physical battery that generates electricity using physical energy such as heat and light.

[0050] As described above, the cylindrical battery core 10 has a specified dimensional tolerance. It should be noted that a cylindrical battery core 10 without dimensional tolerance can also be used.

[0051] As a suitable embodiment of the cylindrical battery core 10, the outer peripheral surface of the cylindrical battery core 10 may have a metal can exposed. By exposing the metal can, it is easy to transfer heat from the exposed metal to the wall portion 12. Therefore, compared with the cylindrical battery core 10 covered with a shrink film, the heat transfer efficiency between the cylindrical battery core 10 with the exposed metal can and the wall portion 12 of the accommodating portion 11 can be improved. In addition, since the outer peripheral surface of the cylindrical battery core 10 is not covered with a shrink film or the like and the metal can is exposed, the dimensional tolerance of the cylindrical battery core 10 can also be reduced. It should be noted that the present invention is not limited to the above embodiment, and the outer peripheral surface of the cylindrical battery core 10 may also be covered with a shrink film or the like.

[0052] Tab

[0053] The tab 20, which is a secondary component of the present disclosure, electrically connects adjacent cylindrical battery cores 10 in the cylindrical battery core 10 housed in the housing portion 11. The cylindrical battery cores 10 can be electrically connected in series through the tab 20. In addition, the cylindrical battery cores 10 can also be electrically connected in parallel through the tab 20. That is, since the tab 20 is electrically connected to the cylindrical battery core 10, a material with good electrical conductivity is preferably used. As an example, a metal is preferred. By arranging the tab 20 in this way, adjacent cylindrical battery cores 10 can be electrically connected in series or in parallel in a state where the wall portion 12 and the outer peripheral surface of the cylindrical battery core 10 are properly fitted together.

[0054] In addition, as described above, when the central axis C of the elliptical space in the housing portion 11 coincides with the central axis of the cylindrical battery core 10, when the cylindrical battery core 10 is housed in the housing portion 11, the distance between the central axis C of one cylindrical battery core 10 and the central axis of the adjacent cylindrical battery core 10 is less likely to change. For this reason, it is possible to more easily perform tab attachment using the tab 20 that electrically connects the cylindrical battery cores 10 to each other.

[0055] Outer packaging component

[0056] The outer packaging component 30, which is a secondary component of the present disclosure, is used to house the above-mentioned battery case 1. As long as it can house the battery case 1, the outer packaging component 30 can be made of any material, but considering the safety of the battery pack 100, an insulating material is preferably used.

[0057] Furthermore, the outer packaging component 30 can be provided with a connector or the like for taking out the electric power generated by the cylindrical battery core 10 housed inside.

[0058] As described above, according to the battery pack 100 of the present disclosure, since the slit 13 is provided in the wall portion 12 that defines the space for housing the cylindrical battery core 10 in parallel with the central axis C of the elliptical cylinder-shaped space, and the minor axis diameter L2 of the elliptical cylinder-shaped space is equal to or less than the diameter of the cylindrical battery core 10, the wall portion 12 separated by the slit 13 can be properly fitted to the outer peripheral surface of the cylindrical battery core 10.

[0059] Second embodiment of the battery pack of the present disclosure

[0060] Refer to Figure 4 And Figure 5 The second embodiment of the battery pack of the present disclosure will be described. The difference between the second embodiment and the above-mentioned first embodiment lies in the position of the slit 13 provided in the wall portion 12. Other configurations are basically the same as those of the first embodiment. Hereinafter, this different configuration will be described.

[0061] In the present embodiment, the slit 13 (13a) provided in the outermost accommodating portion 11 among the plurality of accommodating portions 11 (hereinafter referred to as the outermost accommodating portion 11a) is provided to overlap with the central axis C1 of the elliptical cylinder-shaped space in the accommodating portion 11a when the battery pack 100 is observed from the side.

[0062] By setting the position of the slit 13a of the outermost accommodating portion 11a to the above position, it is possible to suppress the change in the position in the minor axis direction of the outermost accommodating portion 11a before and after the cylindrical battery cell 10 is accommodated in the outermost accommodating portion 11a.

[0063] In the present embodiment, the slits 13 (13b, 13c) provided in the accommodating portions 11 (11b, 11c) located more inward than the outermost accommodating portion 11a among the plurality of accommodating portions 11 are provided at positions overlapping with the central axes C (C2, C3) of the accommodating portions 11 when the battery case 1 is observed from above. In an example shown Figure 5 the slit 13b of the central accommodating portion 11b (hereinafter referred to as the central accommodating portion 11b) located in the center is provided on the lower side of the central accommodating portion 11b ( Figure 5 the negative direction in the minor axis direction). In contrast, the slit 13c of the accommodating portion 11c (hereinafter referred to as the intermediate accommodating portion 11c) between the central accommodating portion 11b and the outermost accommodating portion 11a is provided on the upper side of the intermediate accommodating portion 11c ( Figure 5 the positive direction in the minor axis direction).

[0064] Refer to Figure 5 to describe the operation and effect of the above configuration. First, when the cylindrical battery cell 10 is accommodated in the central accommodating portion 11b, the slit 13b expands. As a result, the intermediate accommodating portion 11c and the outermost accommodating portion 11a move Figure 5 in the positive direction in the minor axis direction. In other words, the arrangement of the accommodating portions 11a to 11c of the battery case 1 observed from the directions of the central axes C1 to C3 is in a V shape (illustration omitted).

[0065] Next, when the cylindrical battery cell 10 is accommodated in the intermediate accommodating portion 11c, the slit 13c expands. As a result, the outermost accommodating portion 11a moves Figure 5 in the negative direction in the minor axis direction (illustration omitted).

[0066] Finally, even when the cylindrical battery cell 10 is accommodated in the outermost accommodating portion 11a, as described above, the change in the position of the outermost accommodating portion 11a is suppressed ( Figure 5(variation in the minor axis direction). It should be noted that the order in which the cylindrical battery core 10 is received in the receiving portion 11a is not limited to the order of the central receiving portion 11b, the intermediate receiving portion 11c, and the outermost receiving portion 11a described above. For example, the cylindrical battery core 10 can be first received in the outermost receiving portion 11a, or the cylindrical battery core 10 can be first received in the intermediate receiving portion 11c.

[0067] Through these actions, deformation of the battery case 1 before and after receiving the cylindrical battery core 10 can be suppressed (in other words, deformation of the entire battery case 1 in the vertical direction (minor axis direction)).

[0068] Furthermore, in the present embodiment, in the receiving portions 11b and 11c that are more inward than the outermost receiving portion 11a among the plurality of receiving portions 11, the slits 13 of the adjacent receiving portions 11 are staggered with each other when the battery case 1 is observed in the front view. The "staggered" as used in this specification means that the slit positions overlap when rotated 180° about the centers of the adjacent receiving portions 11. By adopting such a configuration, the stress on the cylindrical battery core 10 generated by the wall portion 12 can be dispersed, and all the cylindrical battery cores 10 and the battery case 1 can be made to fit more closely. In addition, since the deformation amounts of the left and right battery cases 1 can be made the same with respect to the central receiving portion 11b as the axis, deformation of the battery case 1 in the vertical direction ( Figure 5 minor axis direction) can be suppressed.

[0069] It should be noted that in Figure 5 showing an example of the present embodiment, a scheme is shown in which the formation position of the slit 13c of the intermediate receiving portion 11c is set to the upper side (positive direction of the minor axis direction), and the formation position of the slit 13b of the central receiving portion 11b is set to the lower side (negative direction of the minor axis direction), but it is not limited to this method. For example, even if a scheme is adopted in which the formation position of the slit 13c of the intermediate receiving portion 11c is set to the lower side (negative direction of the minor axis direction), and the formation position of the slit 13b of the central receiving portion 11b is set to the upper side (positive direction of the minor axis direction), the same effect can be achieved.

[0070] Third Embodiment of the Battery Pack of the Present Disclosure

[0071] Refer to Figure 6 and Figure 7 to describe the third embodiment of the battery pack of the present disclosure. The difference between the third embodiment and the above-described first and second embodiments is that: connection members are provided to connect the wall portions of the outermost receiving portions. Other configurations are substantially the same as those of the first and second embodiments described above. Hereinafter, the different configuration will be described.

[0072] Connection Member

[0073] The connecting member 40 of the present embodiment connects the wall portions 12 of the outermost accommodating portions 11 to each other. By providing the connecting member 40, the strength of the battery case 1 can be improved. In addition, by connecting the wall portions 12 of the outermost accommodating portions 11 to each other by the connecting member 40, the deformation of the size of the battery case 1 in the major axis direction can be reduced. That is, the deformation of the entire battery case 1 can be suppressed.

[0074] The material of the connecting member 40 is preferably the same resin material as that of the wall portion 12 described above, but a material different from that of the wall portion 12 may also be used.

[0075] In addition, a control circuit for controlling the power of the cylindrical battery cell 10 may be provided on the connecting member 40. That is, the connecting member 40 can also be used as a member for mounting the control circuit. Therefore, by providing the connecting member 40 as in the present embodiment, this surface portion can be effectively utilized.

[0076] It should be noted that the embodiments disclosed this time are illustrative in all aspects and do not constitute a basis for restrictive interpretation. Therefore, the technical scope of the present disclosure is not defined only by the above-described embodiments, but is defined based on the description of the claims. In addition, the technical scope of the present disclosure includes all changes within the meaning and scope equivalent to the claims.

[0077] The battery pack of the present disclosure includes the following solutions.

[0078] <1>A battery pack including a battery case, the battery case including a plurality of accommodating portions for accommodating a cylindrical battery cell, the accommodating portions being arranged in one direction,

[0079] The accommodating portion has a wall portion that defines a space for accommodating the cylindrical battery cell,

[0080] The wall portion in a state before accommodating the cylindrical battery cell defines an elliptical cylinder-shaped space,

[0081] In the wall portion, a slit is provided parallel to the central axis of the elliptical cylinder-shaped space,

[0082] The direction in which the accommodating portions are arranged in one direction is defined as the major axis direction of the elliptical cylinder-shaped space, the direction perpendicular to the major axis direction is defined as the minor axis direction, and the direction perpendicular to the major axis direction and the minor axis direction and parallel to the central axis of the elliptical cylinder-shaped space is defined as the depth direction,

[0083] The longest minor axis diameter in the minor axis direction of the elliptical cylinder-shaped space in the accommodating portion is equal to or less than the diameter of the cylindrical battery cell.

[0084] <2>The battery pack according to <1>,

[0085] The battery pack includes tabs that electrically connect adjacent cylindrical battery cells to each other.

[0086] <3>The battery pack according to <1> or <2>,

[0087] In a state where the cylindrical battery cell is housed in the housing portion, the central axis of the housing portion coincides with the central axis of the cylindrical battery cell.

[0088] <4>The battery pack according to any one of <1> to <3>,

[0089] The longest major axis diameter in the major axis direction of the elliptical cylinder-shaped space is a length equal to or greater than the diameter of the cylindrical battery cell.

[0090] <5>The battery pack according to any one of <1> to <4>,

[0091] The slit is provided in a boundary region between adjacent housing portions.

[0092] <6>The battery pack according to any one of <1> to <5>,

[0093] The slit formed in the housing portion located at the center is provided at a position overlapping with the central axis of the elliptical cylinder-shaped space in the housing portion when the battery case is viewed from above.

[0094] <7>The battery pack according to any one of <1> to <6>,

[0095] The slits formed in the plurality of housing portions are symmetric with respect to a bisecting plane of the battery case parallel to the minor axis diameter of the elliptical cylinder-shaped space.

[0096] <8>The battery pack according to any one of <1> to <7>,

[0097] The slit provided in the outermost housing portion among the plurality of housing portions is provided at a position overlapping with the central axis of the elliptical cylinder-shaped space in the housing portion when the battery case is viewed from the side.

[0098] <9>The battery pack according to any one of <1> to <8>,

[0099] The slit provided in a housing portion located more inward than the outermost housing portion among the plurality of housing portions is provided at a position overlapping with the central axis of the elliptical cylinder-shaped space in the housing portion when the battery case is viewed from above.

[0100] <10>The battery pack according to any one of <1> to <9>,

[0101] Among the plurality of accommodating portions, in the accommodating portions located more inward than the outermost accommodating portion, the slits of the adjacent accommodating portions stagger each other when the battery case is observed from the front view.

[0102] <11>The battery pack according to any one of <1> to <10>,

[0103] The battery pack has a connecting member that connects the wall portions of the outermost accommodating portions to each other.

[0104] <12>The battery pack according to any one of <1> to <11>,

[0105] The outer peripheral surface of the cylindrical battery core has a metal can exposed.

[0106] <13>The battery pack according to any one of <1> to <12>,

[0107] The length of the accommodating portion in the depth direction is equal to or greater than the length of the cylindrical battery core in the depth direction.

[0108] <14>The battery pack according to any one of <1> to <13>,

[0109] The wall portions of the adjacent accommodating portions are connected to each other.

[0110] <15>The battery pack according to any one of <1> to <14>,

[0111] The short-axis diameter is a length that is 90% or more of the diameter of the cylindrical battery core.

[0112] Industrial Applicability

[0113] The present disclosure can be applied to a battery pack with improved adhesion to a cylindrical battery core.

[0114] Explanation of Reference Numerals

[0115] 1: Battery case; 10: Cylindrical battery core; 11, 11a to 11c: Accommodating portions; 12: Wall portion; 13, 13a to 13c: Slits; 20: Tab; 30: Outer packaging member; 40: Connecting member; 100: Battery pack; A: Boundary region; Ap: Demarcation position; C1 to C3: Central axis; L1: Long-axis diameter; L2: Short-axis diameter; P: Bisecting plane.

Claims

1. A battery pack, comprising a battery housing, the battery housing having a plurality of accommodating portions for accommodating a cylindrical battery cell, and the accommodating portions being arranged in one direction. The accommodating portion has a wall portion, and the wall portion defines a space for accommodating the cylindrical battery cell. Before accommodating the cylindrical battery cell, the wall portion defines an elliptical cylinder-shaped space. In the wall portion, a slit is provided parallel to the central axis of the elliptical cylinder-shaped space. The direction in which the accommodating portions are arranged in one direction is defined as the major axis direction of the elliptical cylinder-shaped space, the direction perpendicular to the major axis direction is defined as the minor axis direction, and the direction perpendicular to the major axis direction and the minor axis direction and parallel to the central axis of the elliptical cylinder-shaped space is defined as the depth direction. The longest minor axis diameter in the minor axis direction of the elliptical cylinder-shaped space in the accommodating portion is equal to or less than the diameter of the cylindrical battery cell.

2. The battery pack according to claim 1. The battery pack includes tabs for electrically connecting adjacent cylindrical battery cells to each other.

3. The battery pack according to claim 1 or 2. When the cylindrical battery cell is accommodated in the accommodating portion, the central axis of the accommodating portion coincides with the central axis of the cylindrical battery cell.

4. The battery pack according to any one of claims 1 to 3. The longest major axis diameter in the major axis direction of the elliptical cylinder-shaped space is a length equal to or greater than the diameter of the cylindrical battery cell.

5. The battery pack according to any one of claims 1 to 4. The slit is provided in the boundary region between adjacent accommodating portions.

6. The battery pack according to any one of claims 1 to 5. The slit formed in the accommodating portion located at the center is provided at a position overlapping the central axis of the elliptical cylinder-shaped space in the accommodating portion when the battery housing is viewed from above.

7. The battery pack according to any one of claims 1 to 6. The slits formed in the plurality of accommodating portions are symmetric with respect to the bisecting plane of the battery housing parallel to the minor axis diameter of the elliptical cylinder-shaped space.

8. The battery pack according to any one of claims 1 to 7. The slit provided in the outermost accommodating portion among the plurality of accommodating portions is provided at a position overlapping the central axis of the elliptical cylinder-shaped space in the accommodating portion when the battery housing is viewed from the side.

9. The battery pack according to any one of claims 1 to 8. The slit provided in the accommodating portion located more inward than the outermost accommodating portion among the plurality of accommodating portions is provided at a position overlapping the central axis of the elliptical cylinder-shaped space in the accommodating portion when the battery housing is viewed from above.

10. The battery pack according to any one of claims 1 to 8. In the accommodating portions located more inward than the outermost accommodating portion among the plurality of accommodating portions, the slits of adjacent accommodating portions are staggered when the battery housing is viewed from the front.

11. The battery pack according to any one of claims 1 to 10. The battery pack has a connecting member connecting the wall portions of the outermost accommodating portions to each other.

12. The battery pack according to any one of claims 1 to 11, wherein a metal can is exposed on the outer peripheral surface of the cylindrical battery cell.

13. The battery pack according to any one of claims 1 to 12, wherein the length of the housing portion in the depth direction is equal to or greater than the length of the cylindrical battery cell in the depth direction.

14. The battery pack according to any one of claims 1 to 13, wherein the wall portions of adjacent housing portions are connected to each other.

15. The battery pack according to any one of claims 1 to 14, wherein the minor axis diameter is a length that is 90% or more of the diameter of the cylindrical battery cell.

Images