Battery pack

Abstract

A battery pack (10) is provided with a cell holder (26, 28, 52, 54) including a holder main body portion (30, 40, 56, 62), and a casing 18 accommodating the cell holder. The holder main body portion holds a plurality of unit cells. Protruding extended portions (32, 42, 58, 64) projecting toward an inner wall of the casing 18 are provided on an outer wall of the holder main body portion. The protruding extended portions include abutting extended portions (32A, 42A, 58A, 64A) which abut the inner wall of the casing.

Description

Battery pack

[0001] The present invention relates to a battery pack including a cell holder that holds a plurality of unit cells and a casing that houses the cell holder.

[0002] WO 2019 / 230879 discloses a cell holder that holds a plurality of unit cells and a battery pack that houses the cell holder in a casing. The casing has a generally rectangular parallelepiped shape, as shown in Figures 1, 2, and 4 of WO 2019 / 230879. The four side surfaces of the casing are generally flat.

[0003] In such battery packs, there are cases where improvements in appearance or design are required. To meet this requirement, it is conceivable to curve at least one side surface of the battery pack so that it bulges from both ends toward the middle in the width direction perpendicular to the longitudinal direction (height direction) of the battery pack.

[0004] At the bulging portion, the inner wall of the casing and the outer wall of the cell holder are separated from each other, i.e., a gap is formed between the cell holder and the casing, making it difficult to position the cell holder within the casing.

[0005] To avoid this problem, it is conceivable to insert a spacer between the cell holder and the casing. However, in this case, the spacer must be fabricated. Furthermore, the spacer must be joined to the outer wall of the cell holder or the inner wall of the casing. This increases the number of steps required to obtain a battery pack. Furthermore, the manufacturing process for the battery pack is complicated.

[0006] A primary object of the present invention is to provide a battery pack that does not require a spacer as a separate member.

[0007] Another object of the present invention is to provide a battery pack in which the cell holders can be easily positioned within the casing.

[0008] According to one embodiment of the present invention, a battery pack is provided that includes a cell holder that holds a plurality of unit cells and a casing that houses the cell holder, wherein the cell holder has a holder main body that holds a plurality of unit cells and a convex extension that extends from the outer wall of the holder main body toward the inner wall of the casing, and the convex extension includes an abutting extension that abuts against the inner wall of the casing.

[0009] According to the present invention, a contact extension is integrally formed on the inner wall of the casing that houses the cell holder. The contact extension contacts the cell holder that holds the unit cell. This positions the cell holder in the casing. This facilitates the assembly of the battery pack. Moreover, in this case, there is no need to separately fabricate spacers. There is also no need to join the spacers to the cell holders. This simplifies the assembly of the battery pack. Furthermore, an increase in the number of work steps is avoided.

[0010] Fig. 1 is a schematic overall perspective view of a battery pack according to an embodiment of the present invention. Fig. 2 is a schematic cross-sectional view in a direction perpendicular to the longitudinal direction of the battery pack. Fig. 3 is a schematic perspective view of a first core pack and a second core pack each composed of four holders. Fig. 4 is a schematic front view of the first core pack and the second core pack.

[0011] In the following description, "bottom" and "top" correspond to the bottom and top of each drawing. Furthermore, in each side wall of the casing 18, the first row holder 26, the second row holder 28, the third row holder 52, and the fourth row holder 54, the side wall facing the arch-shaped portion 16a is referred to as the "front portion." The side wall opposite the front portion is referred to as the "rear portion." These orientations and names are merely for the sake of simplicity and ease of understanding, and do not necessarily represent the orientation or posture of the battery pack when it is being discharged or charged.

[0012] FIG. 1 is a schematic overall perspective view of a battery pack 10 according to this embodiment. The battery pack 10 includes a casing 18. The casing 18 includes a bottom cover 12, a long casing main body 14, and a top cover 16. The casing main body 14 is a hollow body that is generally rectangular and cylindrical, with both ends open in the longitudinal direction (height direction). Here, the both ends in the longitudinal direction refer to the bottom end and top end in FIG. 1. The bottom cover 12 closes the opening at the bottom end of the casing main body 14. The top cover 16 closes the opening at the top end.

[0013] The top cover 16 has an arch-shaped portion 16a and a tab-shaped portion 16b that protrude from the upper surface of the top cover 16. A gripping bar 16c is provided from the arch-shaped portion 16a to the tab-shaped portion 16b. In a plan view of the battery pack 10 seen from the top cover 16 side, the tab-shaped portion 16b, the gripping bar 16c, and the arch-shaped portion 16a are connected in a generally H-shape.

[0014] In the casing main body 14, the front portion 14a facing the arch-shaped portion 16a is curved along the width direction. The width direction is a direction perpendicular to the longitudinal direction. That is, as shown in FIG. 2 , the front portion 14a gradually bulges from the widthwise ends (corners 14c1, 14c2) toward the widthwise intermediate portion. Therefore, the front portion 14a is rounded. By making the front portion 14a bulge most at the widthwise intermediate portion, the battery pack 10 has an excellent aesthetic appearance (design). Note that the front surfaces of the bottom cover 12 and the top cover 16 do not necessarily need to be curved. However, it is preferable that the front surfaces of the bottom cover 12 and the top cover 16 are also curved to match the front portion 14a of the casing main body 14. In this case, the design of the battery pack 10 is further improved.

[0015] Because the casing body 14 has a substantially rectangular cylindrical shape, it has four corners 14c1 to 14c4 that are bent at approximately 90 degrees. Corners 14c1 and 14c2 are the widthwise ends of the front portion 14a. The inner and outer walls of corners 14c1 to 14c4 are gently curved.

[0016] A first core pack 20 and a second core pack 22 shown in Figures 3 and 4 are housed within the casing 18. The first core pack 20 will now be described. The first core pack 20 has a first cell holder 24 that holds a plurality of unit cells (not shown). The first cell holder 24 further has a first row holder 26 as a first holder and a second row holder 28 as a second holder.

[0017] The first row holder 26 has a first main body portion 30 (holder main body portion), a first front side convex extension portion 32, and a first rear side convex extension portion 34. As shown in FIG. 7 of WO 2019 / 230879, the first main body portion 30 has an accommodation hole formed therein for accommodating a unit cell. The first front side convex extension portion 32 is a convex portion that protrudes from the outer wall of the front surface 30a of the first main body portion 30. The first front side convex extension portion 32 extends toward the inner wall of the front surface portion 14a of the casing main body 14. The first rear side convex extension portion 34 is a convex portion that protrudes from the outer wall of the rear surface 30b (see FIG. 2), which is the surface behind the front surface 30a. The first rear side convex extension portion 34 extends toward the inner wall of the rear surface portion 14b of the casing main body 14.

[0018] As can be seen from FIG. 2 , the first front-side convex extension 32 includes a long extension 32A (abutting extension) and a short extension 32B (non-abutting extension). The long extension 32A has a large protrusion amount. Therefore, the long extension 32A abuts against the inner wall of the front portion 14a of the casing body 14. The short extension 32B has a small protrusion amount. Therefore, the short extension 32B does not abut against the inner wall of the front portion 14a of the casing body 14.

[0019] 3 and 4, the long extensions 32A are formed in a lattice pattern on the front surface 30a of the first main body 30. The protrusion amounts of the long extensions 32A are small at the widthwise ends (corner portions 14c1) of the casing main body 14 and increase as they approach the widthwise middle portion. The long extensions 32A provided at the widthwise ends abut against the inner walls of the corner portions 14c1 of the casing main body 14. In other words, the long extensions 32A provided at the widthwise ends are corner-abutting extensions.

[0020] The short extension portion 32B is provided near the abutment surface of the first row holder 26 with the second row holder 28. A portion of the short extension portion 32B protrudes toward the inner wall of the casing body 14 and is then bent toward the second row holder 28. This bending forms a bent portion 36 at the tip of the short extension portion 32B. The bent portion 36 covers the abutment surface of the first row holder 26 with the second row holder 28. As a result, the bent portion 36 covers and conceals a portion of the abutment surface.

[0021] The long extension portion 32A and the short extension portion 32B that are adjacent to each other are connected via a connecting wall portion 38 that is slightly spaced from the front surface 30a of the first main body portion 30. Therefore, a clearance is formed between the front surface 30a of the first main body portion 30 and the connecting wall portion 38. This spacing makes it possible to prevent sink marks from occurring at the base ends of the long extension portion 32A and the short extension portion 32B when the first row holder 26 is manufactured by injection molding from molten resin.

[0022] The second row holder 28 has a second main body portion 40 (holder main body portion), a second front-side convex extension portion 42, and a second rear-side convex extension portion 44. The second main body portion 40 has an accommodation hole formed therein for accommodating a unit cell. The second front-side convex extension portion 42 is a convex portion that protrudes from the outer wall of the front surface 40a of the second main body portion 40. The second front-side convex extension portion 42 extends toward the inner wall of the front surface portion 14a of the casing main body 14. The second rear-side convex extension portion 44 is a convex portion that protrudes from the outer wall of the rear surface 40b (see FIG. 2), which is the surface behind the front surface 40a. The second rear-side convex extension portion 44 extends toward the inner wall of the rear surface portion 14b of the casing main body 14.

[0023] As shown in FIG. 2 , the second front-side convex extension 42 includes a long extension 42A (abutting extension) and a short extension 42B (non-abutting extension). The long extension 42A has a large protrusion amount. Therefore, the long extension 42A abuts against the inner wall of the front portion 14a of the casing main body 14. The long extension 42A becomes smaller from the widthwise middle portion of the casing main body 14 toward the widthwise ends in accordance with the degree of bulging of the casing main body 14. The short extension 42B has a small protrusion amount. Therefore, the short extension 42B does not abut against the inner wall of the front portion 14a of the casing main body 14.

[0024] The short extension 42B is provided near the abutment surface of the second row holder 28 with the first row holder 26. A portion of the short extension 42B extends toward the inner wall of the front portion 14a of the casing body 14, and then is bent toward the first row holder 26. This bending forms a bent portion 46 at the tip of the short extension 32B. The bent portion 46 covers a portion of the abutment surface of the second row holder 28 with the first row holder 26. As a result, the bent portion 46 covers a portion of the abutment surface. Therefore, when the cell holder is viewed from above, the bent portion 36 of the first row holder 26 and the bent portion 46 of the second row holder 28 overlap vertically.

[0025] The second core pack 22 has a second cell holder 50 that holds a plurality of unit cells (not shown). The second cell holder 50 has a third row holder 52 as a first holder and a fourth row holder 54 as a second holder.

[0026] The third row holder 52 has a third main body portion 56 (holder main body portion), a third front side convex extension portion 58, and a third rear side convex extension portion 60. The fourth row holder 54 has a fourth main body portion 62 (holder main body portion), a fourth front side convex extension portion 64, and a fourth rear side convex extension portion 66. Of these, the third main body portion 56 and the fourth main body portion 62 have accommodation holes formed therein to accommodate unit cells.

[0027] The third front-side convex extension 58 and the fourth front-side convex extension 64 are convex portions formed to protrude from the outer walls of the front faces 56 a, 62 a of the third main body portion 56 and the fourth main body portion 62, respectively. The third front-side convex extension 58 and the fourth front-side convex extension 64 extend toward the inner wall of the front face portion 14 a of the casing main body 14. The third rear-side convex extension 60 and the fourth rear-side convex extension 66 are convex portions formed to protrude from the outer walls of the rear faces 56 b, 62 b of the third main body portion 56 and the fourth main body portion 62, respectively. The third front-side convex extension 58 and the fourth front-side convex extension 64 extend toward the inner wall of the rear face portion 14 b of the casing main body 14.

[0028] As shown in FIG. 2 , the third front-side convex extension 58 includes a long extension 58A and a short extension 58B. The fourth front-side convex extension 64 includes a long extension 64A and a short extension 64B. The long extensions 58A and 64A have large protrusions. Therefore, the long extensions 58A and 64A abut against the inner wall of the front portion 14a of the casing body 14. In other words, the long extensions 58A and 64A are abutting extensions. The short extensions 58B and 64B have small protrusions. Therefore, the short extensions 58B and 64B do not abut against the inner wall of the front portion 14a of the casing body 14. In other words, the short extensions 58B and 64B are non-abutting extensions.

[0029] The long extensions 58A and 64A are formed in a lattice pattern on the front faces 56a and 62a of the third and fourth main bodies 56 and 62. The amount of protrusion of the long extensions 58A and 64A decreases from the middle of the casing body 14 toward the widthwise ends (corner portions 14c2) in accordance with the degree of expansion of the casing body 14. The long extensions 64A provided at the widthwise ends of the front face 62a of the fourth main body 62 are corner abutting extensions that abut against the inner walls of the corner portions 14c2 of the casing body 14.

[0030] The short extensions 58B are provided on the third row holders 52 near the contact surfaces with the fourth row holders 54. Parts of the short extensions 58B extend so as to protrude toward the inner wall of the casing body 14, and are then bent toward the fourth row holders 54. This bending forms bent portions 70 at the tips of some of the short extensions 58B.

[0031] The short extension 64B is provided on the fourth row holder 54 near the contact surface with the third row holder 52. A portion of the short extension 64B extends so as to protrude toward the inner wall of the casing body 14, and then is bent toward the third row holder 52. This bending forms a bent portion 72 at the tip of the portion of the short extension 64B.

[0032] The bent portions 70 and 72 cover the contact surfaces so as to hide part of the contact surfaces between the third row holders 52 and the fourth row holders 54. Therefore, when the third row holders 52 and the fourth row holders 54 are viewed in plan, the bent portions 70 of the third row holders 52 and the bent portions 72 of the fourth row holders 54 overlap vertically.

[0033] Similar to the first core pack 20, the adjacent long extensions 58A and short extensions 58B are connected via the connecting wall 38 that is slightly spaced from the front surface 56a of the third main body 56. The adjacent long extensions 64A and short extensions 64B are connected via the connecting wall 38 that is slightly spaced from the front surface 62a of the fourth main body 62. Clearances are formed between the front surface 56a of the third main body 56 and the connecting wall 38, and between the front surface 62a of the fourth main body 62 and the connecting wall 38. These clearances prevent sink marks from occurring at the base ends of the long extensions 58A, 64A, short extensions 58B, and short extensions 64B when the third row holder 52 and the fourth row holder 54 are produced by injection molding from molten resin.

[0034] The rear surface portion 14b of the casing main body 14 is formed substantially flat. Therefore, on the rear surfaces of the first to fourth row holders 26 to 54, the first to fourth rear surface convex extensions 34 to 66 may have substantially the same protrusion amounts. In this case, the first to fourth rear surface convex extensions 34 to 66 are all abutting extensions that abut against the inner wall of the casing main body 14 (including the corners 14c3 and 14c4). The first to fourth rear surface convex extensions 34 to 66 also have bent portions. For example, the bent portions may overlap the abutting surfaces between the first and second row holders 26 and 28. Alternatively, the bent portions may overlap the abutting surfaces between the third and fourth row holders 52 and 54.

[0035] The electrodes of the unit cells housed in the first row holder 26 or the second row holder 28 are electrically connected to each other via a bus bar 90. A lead wire 92 is connected to the bus bar 90. A plurality of lead wires 92 are gathered together to form a harness 94. The harness 94 is hooked between the short extensions 32B and 42B provided along the contact surface between the first row holder 26 and the second row holder 28 on the front surface 14a. The harness 94 is also hooked to the bent portions 36 and 46. The harness 94 is similarly hooked to the bent portions on the back surface 14b.

[0036] The electrodes of the unit cells housed in the third row holder 52 or the fourth row holder 54 are also electrically connected to each other via the bus bar 90. The lead wires 92 connected to the bus bar 90 are gathered together to form a harness 94. The harness 94 is hooked between the short extensions 58B and 64B provided along the contact surfaces of the third row holder 52 and the fourth row holder 54 on the front surface 14a. The harness 94 is also hooked to the bent portions 70 and 72. The harness 94 is similarly hooked to the bent portions on the back surface 14b.

[0037] That is, the harness 94 on the front portion 14a side is positioned by the short extensions 32B, 42B, 58B, 64B, which include the bent portions 36, 46, 70, 72. In this manner, the short extensions 32B, 42B, 58B, 64B (the bent portions 36, 46, 70, 72) serve as restricting portions that restrict the position of the harness 94. Similarly, on the rear portion 14b side, the position of the harness 94 is restricted by the first rear side convex extension 34 to the fourth rear side convex extension 66, which include the bent portions.

[0038] 2 , the first front-side convex extension 32, the first rear-side convex extension 34, the second front-side convex extension 42, and the second rear-side convex extension 44 provided on the first core pack 20 are positioned symmetrically with the third front-side convex extension 58, the third rear-side convex extension 60, the fourth front-side convex extension 64, and the fourth rear-side convex extension 66 provided on the second core pack 22. That is, the first front-side convex extension 32 and the fourth front-side convex extension 64 are positioned equidistant from the center line CL that passes through the opposing portion of the second row holder 28 and the third row holder 52. The first rear-side convex extension 34 and the fourth rear-side convex extension 66 are also positioned equidistant from the center line CL. The positional relationship between the second front side convex extension 42 and the third front side convex extension 58 and the positional relationship between the second rear side convex extension 44 and the third rear side convex extension 60 are also similar.

[0039] The first front-side convex extension 32 and the first rear-side convex extension 34 are positioned 180° apart. In other words, the first front-side convex extension 32 and the first rear-side convex extension 34 are located on an axis parallel to the center line CL. The same applies to the positional relationship between the second front-side convex extension 42 and the second rear-side convex extension 44. The third front-side convex extension 58 and the third rear-side convex extension 60 are also positioned 180° apart. The fourth front-side convex extension 64 and the fourth rear-side convex extension 66 are also positioned 180° apart.

[0040] The battery pack 10 according to this embodiment is basically configured as described above. Next, the effects of the battery pack 10 will be described.

[0041] 1, the front surface 14a of the casing body 14 is formed as a curved wall, which improves the design of the battery pack 10. That is, the battery pack 10 has an excellent aesthetic appearance.

[0042] Here, in the first core pack 20 and the second core pack 22 housed in the casing 18, long extensions 32A, 42A, 58A, and 64A are provided on the front portions of the first row holders 26 to the fourth row holders 54. These long extensions 32A, 42A, 58A, and 64A and the first rear-side convex extensions 34 to the fourth rear-side convex extensions 66 abut against the inner wall of the front portion 14a or the rear portion 14b of the casing main body 14. Therefore, for example, when the first row holders 26 to the fourth row holders 54 are housed in the casing 18, the first row holders 26 to the fourth row holders 54 can be easily positioned within the casing 18. This facilitates the assembly of the battery pack 10.

[0043] As described above, the first row holders 26 to the fourth row holders 54 can be manufactured by injection molding molten resin. That is, the first body portion 30 to the fourth body portion 62, the first front-side convex extension portion 32 to the fourth front-side convex extension portion 64, and the first rear-side convex extension portion 34 to the fourth rear-side convex extension portion 66 are molded simultaneously. This eliminates the need to individually manufacture the first body portion 30 to the fourth body portion 62, the first front-side convex extension portion 32 to the fourth front-side convex extension portion 64, and the first rear-side convex extension portion 34 to the fourth rear-side convex extension portion 66. Therefore, there is no need to join the individually manufactured parts. In other words, this eliminates the need for complex work. Furthermore, an increase in the number of work steps required to obtain the battery pack 10 is avoided.

[0044] When a user loads the battery pack 10 configured in this manner into an external device or a charging device, it is conceivable that the casing body 14 constituting the casing 18 may accidentally come into contact with the external device or the charging device, etc. In this case, an external force will act on the casing body 14.

[0045] However, in the casing body 14, the inner wall of the front portion 14a is supported by the long extensions 32A, 42A, 58A, and 64A, and the inner wall of the rear portion 14b is supported by the first rear-side convex extension 34 to the fourth rear-side convex extension 66. This provides the casing body 14 with sufficient rigidity, making it possible to prevent the casing body 14 from deforming.

[0046] Moreover, the first front-side convex extension 32 to the fourth front-side convex extension 64 and the first rear-side convex extension 34 to the fourth rear-side convex extension 66 are positioned 180° apart. Furthermore, the first front-side convex extension 32 and the fourth front-side convex extension 64 are positioned in a line-symmetrical relationship. The first rear-side convex extension 34 and the fourth rear-side convex extension 66 are also positioned in a line-symmetrical relationship. The second front-side convex extension 42 and the third front-side convex extension 58 are also positioned in a line-symmetrical relationship, and the second rear-side convex extension 44 and the third rear-side convex extension 60 are also positioned in a line-symmetrical relationship. In other words, the convex extensions of the first core pack 20 and the convex extensions of the second core pack 22 are symmetrical. Therefore, the battery pack 10 has uniform rigidity.

[0047] That is, it is possible to prevent the formation of a portion of the battery pack 10 that is significantly less rigid than other portions, and therefore it is possible to prevent the casing body 14 from being deformed regardless of where in the casing body 14 an external force acts.

[0048] In the battery pack 10, it is assumed that the corners 14c1 to 14c4 of the casing main body 14 will come into contact with some kind of object relatively frequently. Here, in the present embodiment, the corner abutment extensions abut against the inner walls of the corners 14c1 to 14c4 of the casing main body 14. This ensures the rigidity of the corners 14c1 to 14c4, and therefore prevents the corners 14c1 to 14c4 from being dented or deformed even if the corners 14c1 to 14c4 come into contact with some kind of object frequently.

[0049] Furthermore, a harness 94 bundling the lead wires 92 is passed through the bent portions 36, 46, 70, 72, etc. provided on the first core pack 20 or the second core pack 22. This prevents the harness 94 from coming into contact with the inner wall of the casing main body 14. Therefore, even if an external force acts on the casing main body 14, the external force is unlikely to be exerted on the harness 94. This maintains the position of the harness 94 within the casing 18. In other words, the position of the harness 94 can be regulated before and after the external force is applied.

[0050] Furthermore, each of the first core pack 20 and the second core pack 22 has two cell holders as described above. The bent portions 36, 46, 70, 72, etc., for hooking the harness 94 are provided so as to straddle the two cell holders. Therefore, even if one of the two cell holders is deformed by an external force, the position of the harness 94 can be regulated by the bent portion of the remaining cell holder.

[0051] That is, in this case, it is possible to prevent the harness 94 from becoming misaligned, and therefore it is also possible to prevent electrical problems such as short circuits between the harnesses 94 from occurring.

[0052] The present invention is not limited to the above-described embodiment, and various configurations can be adopted without departing from the gist of the present invention.

[0053] For example, even if the rear portion 14b of the casing body 14 is flat, the first core pack 20 and the second core pack 22 may be provided with a contact extension portion that abuts the inner wall of the rear portion 14b and a non-contact extension portion that does not abut the inner wall, similar to the front portion 14a.

[0054] The rear portion 14b of the casing body 14 may be curved similarly to the front portion 14a. In this case, it is preferable that the first rear-side convex extension portion 34 to the fourth rear-side convex extension portion 66 have the same configuration as the first front-side convex extension portion 32 to the fourth front-side convex extension portion 64.

Claims

1. A battery pack (10) including a cell holder that holds a plurality of unit cells and a casing (18) that houses the cell holder, the cell holder has a holder body portion (30, 40, 56, 62) that holds the plurality of unit cells, and a convex extension portion (32, 42, 58, 64, 34, 44, 60, 66) that extends from an outer wall of the holder body portion toward an inner wall of the casing, The battery pack includes a contact extension portion (32A, 42A, 58A, 64A) that contacts an inner wall of the casing.

2. 2. The battery pack according to claim 1, wherein the holder main body has a second abutment extension portion disposed at a position 180° away from the position at which the abutment extension portion is disposed, the second abutment extension portion abutting against the inner wall of the casing.

3. 3. The battery pack according to claim 1, wherein the casing has a corner portion (14c1 to 14c4) bent at a predetermined angle, and the convex extension portion includes a corner abutment extension portion that abuts against an inner wall of the corner portion.

4. 4. The battery pack according to claim 1, wherein the protruding extensions are formed at respective linearly symmetrical positions on the holder body.

5. A battery pack as described in any one of claims 1 to 4, wherein the convex extension portion includes a non-contact extension portion (32B, 42B, 58B, 64B) that protrudes less than the contact extension portion and does not contact the inner wall of the casing, and the non-contact extension portion positions a harness (94) that is electrically connected to an electrode of the unit cell.

6. 6. The battery pack according to claim 5, wherein the cell holder has a first holder (26, 52) and a second holder (28, 54) that abut against each other, and the harness is routed along the abutment surfaces of the first holder and the second holder.

7. 7. The battery pack of claim 6, wherein the non-contacting extension portion has a bent portion (36, 46) bent from a direction toward the inner wall of the casing toward the first holder, or a bent portion (70, 72) bent toward the second holder, and the harness is passed through the bent portion.