Battery components, storage batteries, battery packs and electric vehicles

Abstract

To provide a battery constituent, a storage battery, an assembled battery, and an electric vehicle in each of which breakage of a separator can be prevented.SOLUTION: A battery constituent comprises a first electrode plate and a separator that overlap each other in a first direction, the first electrode plate includes a body portion, and an ear portion protruding from the body portion along a second direction orthogonal to the first direction, the separator includes: a first main surface facing the first electrode plate; a joining portion that joins a part of the first main surface to another part; a proximal portion with first thickness; and a thick portion with a second thickness thicker than the first thickness, the joining portion is located outside the first electrode plate when viewed from the first direction, and faces the ear portion in a third direction orthogonal to the first and second directions, and the thick portion is bent at the corner of the body portion facing the joining portion in the second direction.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a battery component, a storage battery, a battery pack, and an electric vehicle. [Background technology]

[0002] A separator is used in a battery to prevent short-circuiting between the positive and negative electrodes. For example, the following Patent Document 1 discloses a method for manufacturing an electrode plate containing a pouched separator. In the following Patent Document 1, the electrode plate is sandwiched by folding the separator. In addition, a pouched separator is provided by forming a plurality of welded portions on the separator. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4661423 Summary of the Invention [Problem to be solved by the invention]

[0004] If a separator housed in a battery is broken and an opening is formed in the separator, the positive electrode and the negative electrode are likely to short-circuit through the opening, and therefore a mode capable of preventing separator breakage is desired.

[0005] An object of one aspect of the present invention is to provide a battery component, a storage battery, a battery pack, and an electric vehicle that can effectively prevent damage to a separator. [Means for solving the problem]

[0006] A battery component according to one aspect of the present invention comprises a first electrode plate and a separator overlapping each other in a first direction, the first electrode plate having a main body portion and an ear portion protruding from the main body portion along a second direction perpendicular to the first direction, the separator having a first main surface facing the first electrode plate, a joint portion joining a part of the first main surface to another part, a base portion having a first thickness, and a thick portion having a second thickness thicker than the first thickness, the joint portion being located outside the first electrode plate when viewed from the first direction and facing the ear portion in a third direction perpendicular to the first and second directions, and the thick portion being bent at a corner of the main body portion facing the joint portion in the second direction.

[0007] In this battery component, the separator has a joint portion that joins a part of the first main surface facing the first plate to another part. The joint portion is located on the outer side of the first plate when viewed from the first direction, and faces the lug portion in the third direction. When the separator is provided with the joint portion, the separator can be pulled toward the joint portion at least along the second direction. As a result, a part of the separator is pressed against a corner portion of the first plate and bent, and receives a load from the corner portion in a concentrated manner. Here, in the battery component, the thick portion of the separator is bent at the corner portion of the first plate. As a result, in the battery component, the load-bearing performance of the portion of the separator that is bent at the corner portion is improved. Therefore, in the one aspect, it is possible to effectively prevent the separator from being damaged.

[0008] The thick portion may have a first rib protruding from the first main surface toward the corner, and the corner may abut against the first rib. In this case, the base of the separator is less likely to abut against the corner.

[0009] The thick portion may have a plurality of first ribs, and the corner may abut against two or more of the first ribs. In this case, the base of the separator is less likely to abut against the corner.

[0010] The thick portion may have a plurality of first ribs, the corner portion may be located on one end side of the first plate in the third direction, and some of the plurality of first ribs may be located on the other end side of the first plate in the third direction.

[0011] The thick portion may have a plurality of first ribs, and some of the plurality of first ribs may be located outside the first plate in the third direction. In this case, when the battery components and the electrolyte are contained in the battery case, the electrolyte flows easily inside the battery components.

[0012] The separator may further have a second main surface located opposite to the first main surface, and the thick portion may have a second rib protruding from the second main surface to the side opposite to the first rib. In this case, when the first electrode plate and another electrode plate different from the first electrode plate are stacked with the separator interposed therebetween, damage to the separator caused by the other electrode plate can be prevented.

[0013] The separator further has a second main surface located opposite to the first main surface, and the thick portion has a first rib protruding from the first main surface toward the corner and a second rib protruding from the second main surface to the side opposite to the first rib, and at least a part of the first rib may overlap the second rib. In this case, the thickness of the base is suppressed, and the base is less likely to abut against the corner. In addition, when the first electrode plate and another electrode plate having a polarity different from that of the first electrode plate are stacked with a separator interposed therebetween, damage to the separator caused by the other electrode plate can be prevented.

[0014] Another part of the first rib may not overlap the second rib. Alternatively, the thick-walled portion may have a plurality of first ribs, and the second rib may be located between two adjacent first ribs in the third direction. Alternatively, the first rib and the second rib may cross each other when viewed from the first direction.

[0015] The separator may further have a gear seal portion located outside the first plate in the third direction and extending in the second direction, and a part of the first main surface and another part of the first main surface may be welded to each other at the joint portion, and a part of the joint portion may overlap the gear seal portion. In this case, the part of the first main surface of the separator and the other part of the first main surface are firmly fixed to each other at the part of the joint portion.

[0016] A storage battery according to one aspect of the present invention includes the battery components described above and a battery case in which the battery components are housed, and the battery components further include a second plate stacked on the first plate in a first direction with a separator interposed therebetween. This storage battery uses battery components that can effectively prevent damage to the separator where a joint is formed. This makes it possible to effectively prevent short circuits between the first plate and the second plate stacked together with the separator interposed therebetween.

[0017] The joint may be located on the opposite side of the bottom of the battery case with the first plate interposed therebetween in the second direction, in which case damage to the joint caused by the bottom of the battery case can be prevented.

[0018] The joint and the lug of the second plate may overlap each other in the first direction, and the dimension of the joint in the third direction may be equal to or greater than the dimension of the lug of the second plate in the third direction. In this case, a short circuit between the lug of the first plate and the lug of the second plate can be effectively prevented at the joint.

[0019] The battery may be a lead acid battery.

[0020] A battery pack according to one aspect of the present invention includes the above-described storage battery. The battery pack includes a storage battery including battery components that can effectively prevent damage to the separator where the joint is formed. As a result, in the storage battery, it is possible to effectively prevent short-circuiting between the first and second plates that are stacked together with the separator interposed therebetween.

[0021] An electric vehicle according to one aspect of the present invention includes the battery pack described above. The electric vehicle includes a storage battery including battery components that can effectively prevent damage to the separator where the joint is formed. As a result, in the storage battery, it is possible to effectively prevent short circuits between the first and second plates that are stacked together with the separator interposed therebetween. Effect of the Invention

[0022] According to one aspect of the present invention, it is possible to provide a battery component, a storage battery, a battery pack, and an electric vehicle that can effectively prevent damage to a separator. [Brief description of the drawings]

[0023] [Figure 1] FIG. 1 is a perspective view showing a part of a storage battery according to an embodiment of the present invention in a cutaway state. [Diagram 2] FIG. 2 is a plan view showing the negative electrode according to the embodiment. [Diagram 3] FIG. 3(a) is a plan view showing a separator sheet, and FIG. 3(b) is a schematic cross-sectional view taken along line IIIb-IIIb in FIG. 3(a). [Figure 4] FIG. 4 is a plan view showing a negative electrode wrapped in a separator. [Diagram 5] FIG. 5 is a perspective view showing a negative electrode wrapped in a separator. [Figure 6] FIG. 6 is an enlarged schematic view of the portion surrounded by the dashed line in FIGS. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. [Figure 8] FIG. 8 is a diagram showing a main part of a first main surface of a separator sheet according to a first modified example. [Figure 9] 9(a) is a schematic end view taken along line IXa-IXa in FIG. 8, and FIG. 9(b) is a schematic end view taken along line IXb-IXb in FIG. [Figure 10] FIG. 10 is an enlarged perspective view of a curved portion and its periphery in a modified example. [Figure 11] FIG. 11 is a cross-sectional view taken along line XI-XI in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Hereinafter, a preferred embodiment of one aspect of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the same elements or elements having the same functions will be denoted by the same reference numerals, and duplicated descriptions will be omitted.

[0025] FIG. 1 is a perspective view showing a part of a storage battery according to this embodiment, with a part cut away. As shown in FIG. 1, the storage battery 1 is, for example, a valve-regulated lead-acid battery. The storage battery 1 is used, for example, as a battery for an automobile, a backup power source used during a power outage, and a main power source for an electric vehicle (or an electric vehicle) such as an electric forklift. In these cases, a battery pack made up of a plurality of storage batteries 1 may be used. For example, the electric vehicle may have a battery pack including a plurality of storage batteries 1. In this embodiment, the storage battery 1 is, for example, a clad-type lead-acid battery equipped with a clad-type electrode. The storage battery 1 includes an electrode group 3, a positive electrode terminal 5A, a negative electrode terminal 5B, a water supply valve 6, and a case 7.

[0026] The electrode group 3 has a plurality of positive electrodes 10, a plurality of negative electrodes 12, and a plurality of separators 13. In the electrode group 3, the positive electrodes 10 and the negative electrodes 12 are alternately arranged. A separator 13 is interposed between adjacent positive electrodes 10 and negative electrodes 12. Therefore, the positive electrodes 10 are stacked on the negative electrodes 12 via the separator 13. In this embodiment, the negative electrodes 12 are arranged at the ends of the arrangement direction (hereinafter, sometimes simply referred to as the "arrangement direction" or the "stacking direction") of the positive electrodes 10, the negative electrodes 12, and the separators 13 in the electrode group 3. In addition, each of the positive electrodes 10, the negative electrodes 12, and the separators 13 is also referred to as a battery component. Hereinafter, the direction in which the multiple positive electrodes 10, the multiple negative electrodes 12, and the multiple separators 13 overlap each other (stacking direction) is referred to as a first direction X. Moreover, a direction perpendicular to the first direction X is defined as a second direction Y, and a direction perpendicular to the first direction X and the second direction Y is defined as a third direction Z. In this embodiment, the second direction Y corresponds to the direction in which the electrode group 3 is housed in the case 7. The second direction Y and the third direction Z are perpendicular to each other, but are not limited to this. It is sufficient that the second direction Y and the third direction Z intersect each other.

[0027] The positive electrode 10 (second electrode plate) is, for example, a clad type positive electrode plate. The positive electrode 10 has a tubular electrode group 14. The tubular electrode group 14 has a plurality of tubular electrodes 15. The plurality of tubular electrodes 15 are arranged in a line. Each of the plurality of tubular electrodes 15 has, for example, a clad tube, a core metal inserted into the clad tube, and a positive electrode material filled between the clad tube and the core metal. The clad tube is a cylindrical porous tube also called a gauntlet, and is formed of, for example, glass, resin, or the like. The positive electrode material may include a positive electrode active material and an additive. The positive electrode active material is, for example, lead powder, red lead, or the like. Examples of the additive include a carbon material, short reinforcing fibers, or the like. The positive electrode active material after chemical formation is, for example, lead dioxide, or the like.

[0028] FIG. 2 is a plan view showing a negative electrode according to an embodiment. The negative electrode 12 (first plate) is a negative electrode plate having a negative electrode grid 12a and an ear portion 12b. The negative electrode grid 12a is a main body of the negative electrode 12 and holds the negative electrode material 12c. In this embodiment, the thickness of the portion of the negative electrode 12 where the negative electrode material 12c is held is greater than the thickness of the negative electrode grid 12a, but is not limited to this. The negative electrode material 12c may contain a negative electrode active material and an additive. The negative electrode active material is, for example, sponge-like lead. Examples of the additive include barium sulfate, a carbon material, or short reinforcing fibers. The ear portion 12b is a terminal portion protruding from the negative electrode grid 12a along the second direction Y. The ear portion 12b and the negative electrode grid 12a do not overlap each other in the arrangement direction. In this embodiment, the negative electrode grid 12a is covered with a separator 13. The negative electrode grid 12a is provided with protrusions 12d and 12e. The protrusions 12d and 12e are arranged at a predetermined interval and are legs protruding outward from the negative electrode grid 12a. The protrusions 12d and 12e protrude in a direction opposite to the protruding direction of the ears 12b. In this embodiment, the protruding direction of the ears 12b and the protruding directions of the protrusions 12d and 12e are each perpendicular to the arrangement direction. Moreover, the ears 12b and the negative electrode grid 12a do not overlap each other in the arrangement direction.

[0029] Each positive electrode 10 is electrically connected to a positive electrode terminal 5A. Each positive electrode 10 and the positive electrode terminal 5A are electrically connected by a positive electrode strap 17. The positive electrode strap 17 is connected to an ear portion 10a of the positive electrode 10. Each negative electrode 12 is electrically connected to a negative electrode terminal 5B. Each negative electrode 12 and the negative electrode terminal 5B are electrically connected by a negative electrode strap 18. The negative electrode strap 18 is connected to an ear portion 12b of the negative electrode 12.

[0030] The separator 13 is a battery component (battery separator) for preventing a short circuit between the positive electrode 10 and the negative electrode 12. The separator 13 is not particularly limited as long as it electronically insulates between the positive electrode 10 and the negative electrode 12 while allowing ions to pass therethrough and has resistance to oxidation on the positive electrode 10 side and reduction on the negative electrode 12 side. Examples of materials for the separator 13 include glass fiber, resin, and inorganic substances. In this embodiment, the separator 13 covers the negative electrode grid 12a and the protruding parts 12d and 12e of the negative electrode 12, and the ear parts 12b of the negative electrode 12 are exposed from the separator 13.

[0031] Here, the structure of a separator sheet, which is a pre-processed product of the separator 13, will be described with reference to Figures 3(a) and (b). Figure 3(a) is a plan view showing the separator sheet. Figure 3(b) is a schematic cross-sectional view taken along line IIIb-IIIb in Figure 3(a). As shown in Figures 3(a) and (b), the separator sheet 30 has a base 31, a pair of edges 32, 33, and a number of ribs 34.

[0032] The base 31 is a sheet-like portion that is a main portion of the separator sheet 30 and is flexible. The base 31 has a first main surface 31a and a second main surface 31b located on the opposite side of the first main surface 31a in the first direction X. In this embodiment, the first main surface 31a and the second main surface 31b have a rectangular shape when viewed from the first direction X, but are not limited thereto.

[0033] The pair of edges 32, 33 are provided at both ends of the separator sheet 30 in the third direction Z. Each of the edges 32, 33 extends from one end of the separator sheet 30 in the second direction Y (e.g., the upper end side of the paper in FIG. 3(a)) to the other end (e.g., the lower end side of the paper in FIG. 3(a)). Each of the edges 32, 33 may extend continuously or intermittently. The edge 32 is provided at one end of the separator sheet 30 in the third direction Z (e.g., the left end side of the paper in FIG. 3(a)), and the edge 33 is provided at the other end of the separator sheet 30 in the third direction Z (e.g., the right end side of the paper in FIG. 3(a)). In this embodiment, the pair of edges 32, 33 are provided with ribs different from the rib 34. For example, each of the pair of edges 32, 33 may be provided with one or more ribs or the like extending from one end of the separator sheet 30 in the second direction Y to the other end.

[0034] The ribs 34 are provided, for example, to improve the durability of the separator sheet 30 and the fluidity of the electrolyte in the case 7. The ribs 34 protrude from the base 31 along the first direction X and are spaced apart from each other. Each of the ribs 34 has a rectangular shape when viewed from the first direction X. Each of the ribs 34 extends from one end to the other end of the separator sheet 30 in the second direction Y and extends parallel to each other. The cross section of the rib 34 perpendicular to the extending direction of the rib 34 has a rectangular shape, but is not limited thereto. The cross section may be, for example, a trapezoid or an inverted trapezoid. The dimension (width) of the rib 34 along the third direction Z is, for example, 0.30% to 2.5% of the dimension of the separator sheet 30 along the third direction Z. The dimension (height) of the rib 34 along the first direction X is, for example, greater than 100% and equal to or less than 1000% of the dimension (thickness) of the base 31 along the first direction X. As shown in FIG. 3(b), the rib 34 has a plurality of first ribs 34a provided on the first main surface 31a and a plurality of second ribs 34b provided on the second main surface 31b. The first rib 34a protrudes from the first main surface 31a along the first direction X. The second rib 34b protrudes from the second main surface 31b to the side opposite to the first rib 34a. The first rib 34a and the second rib 34b have the same shape and completely overlap each other.

[0035] Hereinafter, the portion of the separator sheet 30 where the rib 34 is provided is also referred to as the thick portion TP1 of the separator sheet 30 (and the separator 13). In other words, the portion of the separator sheet 30 (and the separator 13) where the base 31 and the rib 34 overlap each other is also referred to as the thick portion TP1. Therefore, the thick portion TP1 has the rib 34. As described above, the first rib 34a and the second rib 34b completely overlap each other, so that the thickness of the thick portion TP1 in this embodiment corresponds to the sum of the thickness of the base 31, the height of the first rib 34a, and the height of the second rib 34b. When the thickness of the base 31 is the first thickness T1 and the thickness of the thick portion TP1 is the second thickness T2, the second thickness T2 is, for example, greater than 100% and equal to or less than 2000% of the first thickness T1.

[0036] Returning to FIG. 1, the case 7 has a main body 20 and a lid 22. The main body 20 is a box-shaped battery container. The main body 20 is formed of a material such as polypropylene. The main body 20 is composed of four side portions 20a and a bottom portion (not shown). The main body 20 contains the electrode group 3 and an electrolyte. The lid 22 covers the opening of the main body 20. The lid 22 is provided with a positive electrode terminal 5A, a negative electrode terminal 5B, and a refill tap 6. The refill tap 6 is provided between the positive electrode terminal 5A and the negative electrode terminal 5B.

[0037] Next, with reference to FIG. 4 and FIG. 5, a structure in which a negative electrode and a separator are combined, which are included in the battery components, will be described in detail. FIG. 4 is a plan view showing a negative electrode wrapped in a separator. As shown in FIG. 4, the separator 13 corresponds to a bag-shaped processed product of the separator sheet 30, and wraps the negative electrode 12. As described above, the ear portion 12b of the negative electrode 12 is exposed from the separator 13. The separator 13 is formed, for example, by folding one separator sheet 30 in half along the second direction Y, and then sealing a desired portion. At this time, the separator sheet 30 is folded in half so that the negative electrode 12 is sandwiched between the separator sheet 30. At this time, each of the edge portions 32 and 33 is located outside the negative electrode 12 in the third direction Z. From the viewpoint of improving workability, the separator sheet 30 may be folded in half as the negative electrode 12 moves. The separator 13 has a main portion 41 , a pair of seal portions 42 , 43 , a bent portion 44 , and a joint portion 45 .

[0038] The main part 41 is a part that houses the negative electrode grid 12a of the negative electrode 12. The main part 41 is composed of the base part 31 and the edge parts 32, 33 (see FIG. 3(a)) of the separator sheet 30. Therefore, the main part 41 has a first main surface 31a on which the first rib 34a is provided, and a second main surface 31b on which the second rib 34b is provided (see FIG. 3(b)). In this embodiment, the first main surface 31a faces the negative electrode 12, and the second main surface 31b is an exposed surface. Therefore, the positive electrode 10 (see FIG. 1) in the electrode group 3 faces the second main surface 31b of the separator sheet 30. Hereinafter, the part of the main part 41 that overlaps with the negative electrode 12 in the first direction X is referred to as the inner part 41a. Also, the part of the main part 41 that is located outside the inner part 41a when viewed from the first direction X is referred to as the outer part 41b. The boundary between the inner portion 41a and the outer portion 41b abuts, for example, the outer edge of the negative electrode grid 12a. In this embodiment, the inner portion 41a includes a part of the base 31 and parts of the edge portions 32 and 33, and the outer portion 41b includes another part of the base 31 and other parts of the edge portions 32 and 33.

[0039] The pair of seal parts 42, 43 are parts for maintaining the separator sheet 30 folded in two, and are provided on the outer part 41b. The seal part 42 is formed on the edge part 32 (see FIG. 3(a)), and the seal part 43 is formed on the edge part 33 (see FIG. 3(a)). Each of the seal parts 42, 43 is located outside the negative electrode 12 in the third direction Z. Each of the seal parts 42, 43 extends in the second direction Y. This allows the seal parts 42, 43 to suppress the movement of the negative electrode 12 along the third direction Z. The seal parts 42, 43 do not need to be completely sealed. From the viewpoint of the fluidity of the electrolyte in the separator 13, at least one of the seal parts 42, 43 may be provided with an area through which the electrolyte can pass. The seal parts 42, 43 are, for example, ultrasonic welding parts, heat seal parts, cold seal parts, gear seal parts, etc. The gear seal portion is a portion that is mechanically bonded by pressure using a gear. In this embodiment, each of the seal portions 42 and 43 is a gear seal portion that extends from one end of the separator 13 in the second direction Y to the other end of the separator 13.

[0040] The bent portion 44 is a folded portion of the separator sheet 30, and is provided in the outer portion 41b. At least a portion of the bent portion 44 can abut against the negative electrode grid 12a. An opening 44a is provided in a portion of the bent portion 44. The opening 44a is, for example, a portion provided to improve the fluidity of the electrolyte in the separator 13. The opening 44a is, for example, provided in the center of the separator 13 in the third direction Z, but is not limited to this. For example, the opening 44a is formed by cutting a portion of the bent portion 44.

[0041] The joint 45 is a portion for maintaining the state of the separator sheet 30 folded in two, similar to the seal portions 42 and 43. The joint 45 is a portion for joining a part of the first main surface 31a of the separator sheet 30 to another part. The part and the other part are portions that do not overlap the negative electrode 12 in the first direction X, and are located on the opposite side of the bent portion 44 in the second direction Y. Therefore, the joint 45 is located on one end side of the separator 13 in the second direction Y, and is located outside the negative electrode 12 as viewed from the first direction X. Therefore, the joint 45 in the case 7 is located on the opposite side to the bottom (not shown) of the main body 20 (battery case) via the negative electrode 12. In addition, the joint 45 faces the negative electrode lattice body 12a of the negative electrode 12 in the second direction Y, and faces the ear portion 12b in the third direction Z. The joint 45 extends along the third direction Z. Specifically, the joint 45 extends from one end of the separator 13 in the third direction Z to the other end, and is provided in the main portion 41 and the seal portion 42. That is, a part of the joint 45 overlaps with the seal portion 42. The joint 45 is, for example, a portion of the separator sheet 30 itself that is welded. In this case, in the joint 45, a part of the first main surface 31a and another part are welded. From the viewpoint of preventing welding defects, the joint 45 may be formed by ultrasonic welding or the like. The joint 45 may be provided after the seal portions 42, 43 are formed, or may be provided before the seal portions 42, 43 are formed.

[0042] 1, in the electrode group 3, the joint 45 overlaps with the ear 10a of the positive electrode 10 in the first direction X. From the viewpoint of suppressing the occurrence of a short circuit between the positive electrode 10 and the negative electrode 12 via the ear 10a, both ends of the joint 45 in the third direction Z are located outside the ear 10a as viewed from the first direction X. For this reason, the dimension S1 of the joint 45 in the third direction Z is equal to or greater than the dimension S2 of the ear 10a in the third direction Z. For example, the dimension S1 is equal to or greater than 100% and equal to or less than 600% of the dimension S2.

[0043] Fig. 5 is a perspective view showing a negative electrode wrapped in a separator. As shown in Fig. 5, a curved portion 51 is provided on an outer portion 41b of the separator 13. The curved portion 51 is provided on at least a part of the outer portion 41b located closer to the ear portion 12b side than the negative electrode grid body 12a (see Figs. 2 and 4) in the second direction Y. The curved portion 51 is provided with a joint portion 45. The curved portion 51 is formed, for example, by deformation of the separator 13 accompanying the formation of the joint portion 45.

[0044] Next, the curved portion 51 will be described in detail with reference to Fig. 6 and Fig. 7. Fig. 6 is an enlarged schematic view of a portion surrounded by a dashed line in Fig. 4 and Fig. 5. Fig. 7 is a cross-sectional view taken along line VII-VII in Fig. 6. As shown in Fig. 6 and Fig. 7, the curved portion 51 has a first extension portion 52, an inflection portion 53, and a second extension portion 54.

[0045] The first extension portion 52 is a portion of the separator 13 that extends from the boundary BD between the inner portion 41a and the outer portion 41b toward the inflection portion 53, and is the closest to the negative electrode 12 in the curved portion 51. The first extension portion 52 extends, for example, from the boundary BD to the joint 45 or its vicinity in the second direction Y. The first extension portion 52 exhibits flexibility between the boundary BD and the inflection portion 53. In this embodiment, a part of the first extension portion 52 extends from one side to the other side of the negative electrode 12 in the first direction X. The inflection portion 53 is a portion that includes an inflection point of the curved portion 51, and is located between the first extension portion 52 and the second extension portion 54. The inflection portion 53 is located, for example, in the joint 45 or in a region nearby the joint 45. The region nearby is a region that is near the joint 45 and is located closer to the negative electrode 12 side than the joint 45 in the second direction Y. The second extension portion 54 is a free end extending from the inflection portion 53, and is the farthest from the negative electrode 12 in the curved portion 51. The second extension portion 54 extends from the other side of the negative electrode 12 toward one side in the first direction X. Therefore, the part of the first extension portion 52 and the second extension portion 54 extend toward opposite sides to each other in the first direction X. In this embodiment, the curved portion 51 is curved to draw, for example, a J-shape or a U-shape when viewed from the third direction Z. In this embodiment, the joint 45 is included in at least the second extension portion 54.

[0046] In FIG. 7, the separator 13 is bent at the corner 12f located on one side of the negative electrode 12 in the first direction X among the outer edges of the negative electrode grid 12a overlapping the boundary BD. As a result, as described above, the portion of the separator 13 that corresponds to the part of the first extension portion 52 and extends from the corner 12f to the inflection portion 53 extends from one side of the negative electrode 12 in the first direction X to the other side. On the other hand, the separator 13 is not bent at the corner 12g located on the other side of the negative electrode 12 in the first direction X among the outer edges of the negative electrode grid 12a overlapping the boundary BD, but this is not limited thereto. As described above, since the first extension portion 52 exhibits flexibility, for example, the separator 13 may be bent at the corner 12g in the storage battery 1. From the viewpoint of preventing damage to the separator 13, each of the corners 12f and 12g may be chamfered. In this case, each of the corners 12f, 12g may be, for example, rounded. Each of the corners 12f, 12g may be chamfered after the formation of the negative electrode 12, but is not limited to this. The corners 12f, 12g may have a shape such as a rounded surface without a chamfering process.

[0047] The first rib 34a of the separator 13 abuts against the corner 12f. The first rib 34a is bent at the corner 12f. In this embodiment, the thick portion TP1 of the separator 13 including the first rib 34a abuts against the corner 12f and is bent. The base portion 31 of the separator 13 located around the thick portion TP1 is also bent at or near the corner 12f (see FIG. 6). The base portion 31 may abut against the corner 12f or may be separated from the corner 12f. The corner 12f corresponds to a portion of the outer edge of the negative electrode grid 12a that faces the joint 45 in the second direction Y, and is located on one end side of the negative electrode 12 in the third direction Z. In this embodiment, some of the multiple first ribs 34a protrude toward and abut against the corner 12f, and other parts of the multiple first ribs 34a are located on the other end side of the negative electrode 12 in the third direction Z. The portion of the negative electrode 12 located on the one end side in the third direction Z corresponds to the portion of the negative electrode 12 closer to the seal portion 42 than the seal portion 43 in the third direction Z. Therefore, the portion of the negative electrode 12 located on the other end side in the third direction Z corresponds to the portion of the negative electrode 12 closer to the seal portion 43 than the seal portion 42 in the third direction Z. The ear portion 12b of the negative electrode 12 is located on the other end side in the third direction Z.

[0048] Next, an example of a manufacturing method of the storage battery 1 in this embodiment will be briefly described. First, the separator sheet 30 and the negative electrode 12 are prepared. At this time, the first main surface 31a of the separator sheet 30 and the negative electrode 12 are opposed to each other. Next, the separator sheet 30 is folded in half to form a bent portion 44 and sandwich the negative electrode 12 between the separator sheet 30. At this time, the negative electrode grid 12a of the negative electrode 12 is completely covered by the separator sheet 30, and a part of the ear portion 12b of the negative electrode 12 is exposed from the separator sheet 30. Next, the seal portions 42, 43 and the joint portion 45 are formed on the separator sheet 30. The seal portions 42, 43 are formed by, for example, a gear seal or the like. The joint portion 45 is formed by, for example, ultrasonic welding using an ultrasonic welding device including a horn. When the joint portion 45 is formed, the separator sheet 30 is drawn to the joint portion 45 at least in the second direction Y. Since the bent portion 44 is formed in the separator sheet 30, tension is generated in the separator sheet 30 at least in the second direction Y. This causes a part of the separator sheet 30 to be pressed against the corner portion 12f of the negative electrode 12. Next, an opening 44a is formed in the bent portion 44, thereby forming the separator 13 that wraps the negative electrode 12.

[0049] Next, a plurality of positive electrodes 10 and a plurality of negative electrodes 12 wrapped in separators 13 are prepared. Then, the positive electrodes 10 and the negative electrodes 12 are alternately stacked. Then, the ears 10a of the positive electrodes 10 are electrically connected to each other via the positive electrode straps 17, and the ears 12b of the negative electrodes 12 are electrically connected to each other via the negative electrode straps 18. This forms an electrode group 3 including a plurality of positive electrodes 10, a plurality of negative electrodes 12, and a plurality of separators 13. Then, the electrode group 3 is housed in a main body 20, and the main body 20 is sealed with a lid 22. At this time, each positive electrode 10 is electrically connected to a positive electrode terminal 5A, and each negative electrode 12 is electrically connected to a negative electrode terminal 5B. Then, an electrolyte is supplied into the case 7 through the water supply tap 6. This produces a storage battery 1.

[0050] In the battery components included in the storage battery 1 according to the present embodiment described above, the separator 13 has a joint 45 that joins a part of the first main surface 31a facing the negative electrode 12 to another part. The joint 45 is located at the outer portion 41b of the negative electrode 12 when viewed from the first direction X, and faces the ear portion 12b in the third direction Z. When the joint 45 is provided on the separator 13, the separator 13 can be pulled to the joint 45 at least along the second direction Y. As a result, a part of the separator 13 is pressed against the corner portion 12f of the negative electrode 12 and bent, and receives a load from the corner portion 12f in a concentrated manner. Here, in this embodiment, the thick portion TP1 of the separator 13 is bent at the corner portion 12f of the negative electrode 12. That is, the thick portion TP1 is located in a portion of the separator 13 that is pressed against the corner portion 12f and bent. This effectively improves the load-bearing performance of the portion of separator 13 that is bent at corner 12f. Therefore, in this embodiment, breakage of separator 13 can be effectively prevented.

[0051] In addition, in this embodiment, the thick portion TP1 is pressed against the corner 12f of the negative electrode 12 and bent, so that the portion of the base 31 of the separator 13 where the first rib 34a is not provided is less likely to be pressed against the corner 12f. Therefore, the load from the corner 12f is less likely to be applied to the portion of the separator 13 with a relatively low load-bearing performance (i.e., the portion of the separator 13 where the rib 34 is not provided). Therefore, in this embodiment, as described above, it is possible to effectively prevent the separator 13 from being damaged.

[0052] In this embodiment, the thick portion TP1 has a first rib 34a protruding from the first main surface 31a toward the corner 12f, and the corner 12f abuts against the first rib 34a. In addition, the thick portion TP1 has a plurality of first ribs 34a, and the corner 12f abuts against two or more first ribs 34a. This makes it easier for the base 31 of the separator 13 to move away from the corner 12f. This makes it difficult for the base 31 of the separator 13 to receive a load from the corner 12f, so that damage to the separator 13 caused by the joint 45 and the corner 12f can be effectively prevented.

[0053] In this embodiment, the thick portion TP1 has a plurality of first ribs 34a, the corner portion 12f is located on one end side of the negative electrode 12 in the third direction Z, and some of the plurality of first ribs 34a are located on the other end side of the negative electrode 12 in the third direction Z. This makes it possible to prevent damage to the separator 13 caused by the outer edge of the negative electrode 12 other than the corner portion 12f.

[0054] In this embodiment, the separator 13 has a second main surface 31b located opposite to the first main surface 31a, and the thick portion TP1 has a second rib 34b protruding from the second main surface 31b to the side opposite to the first rib 34a. Therefore, when the positive electrode 10 and the negative electrode 12 are stacked with the separator 13 interposed therebetween, damage to the separator 13 caused by the positive electrode 10 can be prevented.

[0055] In this embodiment, the separator 13 has a second main surface 31b located on the opposite side to the first main surface 31a, and the thick portion TP1 has a first rib 34a protruding from the first main surface 31a toward the corner 12f and a second rib 34b protruding from the second main surface 31b to the opposite side to the first rib 34a, and at least a part of the first rib 34a overlaps with the second rib 34b. Therefore, the thickness of the base 31 is suppressed, and the base 31 of the separator 13 is less likely to abut against the corner 12f. In addition, when the positive electrode 10 and the negative electrode 12 are stacked via the separator 13, damage to the separator 13 caused by the positive electrode 10 can be prevented.

[0056] In this embodiment, the separator 13 has a seal portion 42 that is a gear seal portion located outside the negative electrode 12 in the third direction Z and extending in the second direction Y, and at a joint portion 45, a part of the first main surface 31a and another part are welded together, and a part of the joint portion 45 overlaps the gear seal portion. Therefore, at the part of the joint portion 45, the part of the first main surface 31a of the separator 13 and the other part are firmly fixed together.

[0057] By using the storage battery 1 in which the battery components including the positive electrode 10, the negative electrode 12, and the separator 13 according to this embodiment are used, it is possible to effectively prevent damage to the separator 13 on which the joint 45 is formed. Therefore, it is possible to effectively prevent short-circuiting between the positive electrode 10 and the negative electrode 12, which are stacked on top of each other via the separator 13. In addition, in this embodiment, the joint 45 is located on the opposite side of the bottom of the main body 20 via the negative electrode 12 in the second direction Y. Therefore, when the electrode group 3 including the separator 13 is housed in the main body 20, it is possible to prevent damage to the joint 45 due to collision of the separator 13 with the bottom. Furthermore, in this embodiment, the joint 45 and the ear 10a of the positive electrode 10 overlap each other in the first direction X, and the dimension of the joint 45 in the third direction Z is equal to or greater than the dimension of the ear 10a of the positive electrode 10 in the third direction Z. Therefore, it is possible to effectively prevent short-circuiting between the negative electrode 12 and the ear 10a of the positive electrode 10 at the joint 45.

[0058] In the following, modified examples of the above embodiment will be described with reference to Figures 8 to 11. In the following modified examples, explanations of points that overlap with the above embodiment will be omitted. Therefore, in the following, differences from the above embodiment will be mainly described.

[0059] FIG. 8 is a diagram showing a main part of the first main surface of the separator sheet according to the first modification. FIG. 9(a) is a schematic end view taken along line IXa-IXa in FIG. 8, and FIG. 9(b) is a schematic end view taken along line IXb-IXb in FIG. 8. As shown in FIG. 8, in the separator sheet 30A according to the first modification, the shape of the first ribs formed on the first main surface 31a is different from that of the above embodiment. Specifically, as shown in FIG. 8, the first main surface 31a is provided with a first rib 61 that extends linearly so as to be inclined with respect to the second direction Y and the third direction Z when viewed from the first direction X. The cross section of the first rib 61 perpendicular to the extending direction of the first rib 61 has a rectangular shape, but is not limited thereto. The cross section may be, for example, a trapezoidal shape or an inverted trapezoidal shape.

[0060] Although not shown in this modification, the first rib 61 and the second rib 34b cross each other when viewed from the first direction X. Therefore, as shown in FIG. 9(a), a part of the first rib 61 overlaps with the second rib 34b, and as shown in FIG. 9(b), another part of the first rib 61 does not overlap with the second rib 34b. In this modification, the part of the separator sheet 30A where at least the first rib 61 is provided is also referred to as the thick part TP2. In other words, the thick part TP2 according to this modification only needs to include the first rib 61, and does not need to include the second rib 34b. Therefore, the thickness of the thick part TP2 corresponds to the sum of the thickness of the base 31 and the height of the first rib 61 in FIG. 9(a). Also, in FIG. 9(b), the thickness of the thick part TP2 corresponds to the sum of the thickness of the base 31, the height of the first rib 61, and the height of the second rib 34b. In this modified example, the height of the first rib 61 is greater than the height of the second rib 34b, but is not limited to this.

[0061] Returning to FIG. 8, the first rib 61 has a third rib 62 and a fourth rib 63. The third rib 62 and the fourth rib 63 are arranged along the second direction Y. In this embodiment, a rib group 64 including a plurality of third ribs 62 and a rib group 65 including a plurality of fourth ribs 63 are arranged alternately along the second direction Y. In the rib group 64, a plurality of third ribs 62 are arranged along the third direction Z. Similarly, in the rib group 65, a plurality of fourth ribs 63 are arranged along the third direction Z. A gap SP is provided between the rib groups 64 and 65. From the viewpoint of maintaining the performance of the separator sheet 30A, the dimension of the gap SP along the second direction Y is, for example, 5% or more and 200% or less of the dimension of the first rib 61 along the second direction Y. The lower limit of the dimension of the gap SP may be 10%, 15%, or 20%. The upper limit of the dimension of the gap SP may be 150%, 120%, or 100%. The distance between adjacent third ribs 62 in the rib group 64 and the distance between adjacent fourth ribs 63 in the rib group 65 are the same, but are not limited to this.

[0062] The third rib 62 and the fourth rib 63 extend to intersect with each other. In this modification, the third rib 62 extends from one end side to the other end side of the separator sheet 30A in the third direction Z as it moves from one end side to the other end side of the separator sheet 30A in the second direction Y. The fourth rib 63 extends from the other end side to one end side of the separator sheet 30A in the third direction Z as it moves from one end side to the other end side of the separator sheet 30A in the second direction Y. Therefore, in this modification, a fishbone structure is formed by the third rib 62 and the fourth rib 63 adjacent to each other in the second direction Y. When viewed from the third direction Z, the angle θ1 formed by the third rib 62 and the first direction X is, for example, greater than 90° and less than 150°, and the angle θ2 formed by the fourth rib 63 and the first direction X is, for example, greater than 90° and less than 90°.

[0063] Fig. 10 is an enlarged perspective view of the curved portion and its periphery in this modified example. Fig. 11 is a cross-sectional view taken along line XI-XI in Fig. 10. As shown in Figs. 10 and 11, in this modified example, the thick portion TP2 of the separator 13A is bent at the corner 12f of the negative electrode 12. In other words, in this modified example, the first rib 61 is bent at the corner 12f of the negative electrode 12. Furthermore, the thick portion TP2 is bent at the corner 12g of the negative electrode 12, but is not limited thereto.

[0064] The above-described modified example also achieves the same effects as those of the above-described embodiment. In addition, the storage battery including the separator according to this modified example allows the electrolyte to flow easily between the negative electrode 12 and the first main surface 31a. Furthermore, the first rib 61 can easily abut against the corners of the negative electrode grid 12a facing the seal portion 42 in the third direction Z, and the corners of the negative electrode grid 12a facing the seal portion 43 in the third direction Z. Therefore, in the modified example, when the separator is bent at the corners, damage to the separator caused by the corners can be effectively prevented.

[0065] The battery components according to one aspect of the present invention are not limited to the above embodiment and the above modification. For example, in the above modification, the fishbone structure is formed by the third rib and the fourth rib provided on the first main surface, but the present invention is not limited to this. The fishbone structure may be formed only on the second main surface, or the fishbone structure may be formed on both the first main surface and the second main surface.

[0066] In the above embodiment, the rib extends linearly when viewed from the first direction, but is not limited thereto. For example, the rib may extend in a wavy line or a zigzag line when viewed from the first direction. Also, the rib may be dot-shaped, circular, elliptical, or polygonal when viewed from the first direction. Alternatively, the rib may be polygonal pyramid-shaped, polygonal truncated pyramid-shaped, conical, or conical truncated. The cross section of the rib may be semicircular or polygonal. The rib may extend along the second direction or along the third direction.

[0067] In the above embodiment and the above modified example, the thick portion includes a rib, but is not limited to this. For example, the thick portion may be a portion thicker than the thinnest portion of the separator and may not include a rib. The separator may have both a thick portion with a rib and a thick portion without a rib.

[0068] In the above embodiment and the above modified example, the separator sheet is folded in half along the second direction, but this is not limited thereto. For example, depending on the dimensions of the electrode group, the separator sheet may be folded in half along the third direction. In this case, an opening does not need to be provided at the bent portion of the separator.

[0069] In the above embodiment and the above modified example, the separator is a bag-shaped workpiece, but is not limited thereto. For example, the separator may be a cylindrical workpiece. In this case, the joints may be provided on both sides in the second direction, or on only one side in the second direction. For example, the joints may be provided only on the opposite side of the ears of the negative electrode across the negative electrode grid in the second direction.

[0070] In the above embodiment and the above modified example, the separator is formed from one separator sheet, but is not limited thereto. For example, the separator may be formed from a plurality of separator sheets. In this case, the seal portion may be formed on both ends of the separator in the third direction, or the seal portion may be formed only on one side in the third direction. In addition, it is preferable that the joint portion is formed on both sides of the separator in the second direction, but is not limited thereto. The joint portion may be formed only on one side in the second direction. Therefore, when the separator is formed from a plurality of separator sheets, the separator may be a bag-shaped workpiece, a cylindrical workpiece, or a workpiece different from the bag-shaped workpiece and the cylindrical workpiece. When the welding portion is provided on the opposite side of the ear portion of the negative electrode across the negative electrode grid in the second direction, it is preferable that the joint portion is provided so as to face the convex portion of the negative electrode in the second direction. In this case, the convex portion is less likely to be exposed from the separator, so that a short circuit is less likely to occur. When the joint is provided to face the protruding portion of the negative electrode in the second direction, it is more preferable that the dimension of the joint in the third direction is larger than the dimension of the protruding portion in the third direction, in which case the protruding portion is less likely to be exposed satisfactorily from the separator.

[0071] In the above embodiment and the above modified example, the battery case includes a plurality of separators, but is not limited thereto. For example, the plurality of positive electrodes and the plurality of negative electrodes included in the electrode group may be separated by one separator sheet. In this case, for example, the separator sheet is folded in an accordion-like shape in the arrangement direction. In the electrode group, the positive electrode is arranged to be sandwiched between the first main surface of the accordion-like separator sheet, and the negative electrode is arranged to be sandwiched between the second main surface of the separator sheet. By providing a joint portion in a part of the separator sheet, it is possible to suppress the deviation between the separator sheet and the positive electrode and the negative electrode. In this case, it is possible to reduce the manufacturing cost of the electrode group.

[0072] In the above embodiment and the above modified example, the first rib provided on the first main surface overlaps at least a part of the second rib provided on the second main surface, but this is not limited thereto. For example, the first rib and the second rib may not overlap each other. For example, a part of the second ribs may be located between two adjacent first ribs in the third direction. Also, a part of the first ribs may be located outside the negative electrode in the third direction. In this case, when the battery components and the electrolyte are contained in the battery container, the electrolyte is likely to flow through the battery components. Similarly, a part of the second ribs may be located outside the negative electrode in the third direction. [Explanation of symbols]

[0073] 1...storage battery, 3...electrode group, 5A...positive electrode terminal, 5B...negative electrode terminal, 7...case, 10...positive electrode (second electrode plate), 10a...ear, 12...negative electrode (first electrode plate), 12a...negative electrode grid, 12b...ear, 12c...negative electrode material, 12d, 12e...projection, 12f, 12g...corner, 13...separator, 20...main body, 22...lid, 30, 30A...separator sheet, 31...base, 31a...first main surface, 31b...second Main surface, 32, 33...edge, 34...rib, 34a, 61...first rib, 34b...second rib, 41...main portion, 41a...inner portion, 41b...outer portion, 42, 43...sealing portion, 44...bent portion, 44a...opening, 45...joint, 51...curved portion, 52...first extension portion, 53...inflection portion, 54...second extension portion, 62...third rib, 63...fourth rib, 64, 65...group of ribs, TP1, TP2...thick portion.

Claims

1. a first electrode plate and a separator overlapping each other in a first direction; The first electrode plate has a main body portion and a lug portion protruding from the main body portion along a second direction perpendicular to the first direction, the separator has a first main surface facing the first electrode plate, a joint portion that joins a part of the first main surface to another part, a base portion having a first thickness, and a thick portion having a second thickness that is thicker than the first thickness, the joint portion is located on an outer side of the first electrode plate when viewed from the first direction, and faces the lug portion in a third direction perpendicular to the first direction and the second direction; The thick portion is bent at a corner of the main body portion facing the joint portion in the second direction. Battery components.

2. the thick portion has a first rib protruding from the first main surface toward the corner portion, The battery component of claim 1 , wherein the corner abuts the first rib.

3. The thick portion includes a plurality of the first ribs, The battery component of claim 2 , wherein the corner abuts two or more of the first ribs.

4. The thick portion includes a plurality of the first ribs, the corner portion is located on one end side of the first electrode plate in the third direction, The battery component according to claim 2 , wherein some of the plurality of first ribs are located on the other end side of the first electrode plate in the third direction.

5. The thick portion includes a plurality of the first ribs, The battery component according to claim 2 , wherein some of the plurality of first ribs are located on an outer side of the first plate in the third direction.

6. The separator further has a second main surface located opposite the first main surface, The battery component according to any one of claims 2 to 5, wherein the thick portion has a second rib protruding from the second main surface to a side opposite to the first rib.

7. The separator further has a second main surface located opposite the first main surface, The thick portion is a first rib protruding from the first main surface toward the corner; a second rib protruding from the second main surface on a side opposite to the first rib; The battery component of claim 1 , wherein at least a portion of said first rib overlaps said second rib.

8. The battery component of claim 7 , wherein another portion of said first rib does not overlap said second rib.

9. The thick portion includes a plurality of the first ribs, The battery component according to claim 7 or 8, wherein the second rib is located between two of the first ribs adjacent to each other in the third direction.

10. The battery component according to any one of claims 7 to 9, wherein the first rib and the second rib intersect with each other when viewed from the first direction.

11. The separator further includes a gear seal portion located outside the first plate in the third direction and extending in the second direction, At the joint portion, the part of the first main surface and the other part are welded to each other, The battery component according to any one of claims 1 to 10, wherein a portion of the joint overlaps the gear seal portion.

12. A battery component according to any one of claims 1 to 11, a battery case in which the battery components are housed; Equipped with The battery component further includes a second plate laminated on the first plate via the separator in the first direction. Storage battery.

13. The storage battery according to claim 12 , wherein the joint is located on an opposite side of the bottom of the container via the first plate in the second direction.

14. The joint portion and the lug portion of the second electrode plate overlap each other in the first direction, The storage battery according to claim 12 or 13, wherein a dimension of the joint in the third direction is equal to or greater than a dimension of the lug of the second plate in the third direction.

15. The battery according to any one of claims 12 to 14, which is a lead acid battery.

16. A battery pack comprising the storage battery according to any one of claims 12 to 15.

17. An electric vehicle comprising the battery pack according to claim 16.

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