Battery pack

Abstract

The present invention allows a lead plate to be simply and easily disposed at an accurate position of a battery holder, so that the lead plate and an end electrode can be electrically connected in a reliable and stable manner. This battery pack comprises: a battery cell 1 provided with an end electrode 2; a battery holder 10 in which the battery cell 1 is disposed at a fixed position; and a lead plate 20 disposed at a fixed position of the battery holder 10 and connected to the end electrode 2. The battery holder 10 has an end face holder portion 11 and a bottom face holder portion 12 which are integrally structured. The lead plate 20 is a metal plate having an L-shaped overall shape and comprises an end face lead portion 23, a bottom face lead portion 24, and a first locking structure 30 and a second locking structure 40 for arranging the lead plate 20 and the battery holder 10 at fixed positions, wherein: the first locking structure 30 enables the end face lead portion 23 to move in the Y-axis direction and prevents positional deviation in the Z-axis direction; and the second locking structure 40 enables the bottom face lead portion 24 to move in the Z-axis direction and prevents positional deviation in the Y-axis direction.

Description

Battery pack

[0001] The present disclosure relates to a battery pack including a battery cell, a battery holder, and a lead plate, and more particularly to a battery pack in which the lead plate is connected to a battery cell disposed in a fixed position in a battery holder.

[0002] A battery pack 900 has been developed in which battery cells and lead plates are arranged in fixed positions in a battery holder, and the lead plates are connected to the end electrodes of the battery cells (Patent Document 1). As shown in Fig. 18, the battery pack 900 in Patent Document 1 has a locking portion 930 for locking a lead plate 920 on the end surface of a battery holder 910 where the end electrodes of the battery cells are exposed. The battery holder 910 in Fig. 18 has a pair of locking portions 930 arranged on the end surface of the battery holder 910 to lock both sides of the lead plate 920. The lead plate 920 is inserted into the pair of locking portions 930 arranged spaced apart from each other above and below and set on the end surface of the battery holder 910. The battery holder 910 in Fig. 18 has parallel grooves for setting multiple rows of battery cells in fixed positions, with both ends of the parallel grooves open. The battery cells are set in their fixed positions by placing their end electrodes in the openings at both ends and setting them in the parallel grooves. The lead plate 920 set in the battery holder 910 is set between a pair of locking portions 930 and is close to the end electrodes of the battery cells set in the parallel grooves. The lead plate 920 placed in this position can be welded in close contact with the end electrodes to form an electrical connection.

[0003] Patent No. 5955694

[0004] In the battery pack shown in Figure 18, the lead plate 920 is inserted between a pair of latches 930 to position the lead plate 920 in a fixed position in the battery holder 910, making it difficult to accurately position the lead plate 920 without misalignment. Relative misalignment between the lead plate 920 and the end electrode prevents the lead plate 920 from being tightly connected to the end electrode, hindering stable electrical connection between both ends of the end electrode. While it is possible to position the lead plate 920 in a fixed position using a magnet with a jig to tightly connect the lead plate 920 to the end electrode, lead plates made of aluminum or other materials cannot be magnetized and cannot be positioned in a fixed position, which poses a problem.

[0005] Another method involves creating a through hole in the lead plate, inserting a positioning boss on the battery holder into the through hole, and then heating and crushing the positioning boss to fix the lead plate in a fixed position on the battery holder. However, this method has the problem of requiring a lot of processing time.

[0006] The present disclosure has been developed with the objective of further resolving the above-mentioned drawbacks, and one of the objectives of the present disclosure is to provide a battery pack in which the lead plate can be simply and easily positioned accurately in the battery holder, thereby ensuring a stable electrical connection between the lead plate and the end electrode.

[0007] A battery pack according to one embodiment of the present disclosure has all of the following configurations (a) to (e): (a) The battery pack includes a battery cell having an end electrode at its end, a battery holder that positions the battery cell in a fixed position, and a lead plate that is positioned in a fixed position on the battery holder and connected to the end electrode. (b) The battery holder is a molded body that integrates an end holder portion that is positioned opposite the end electrode of the battery cell and a bottom holder portion that is positioned on the bottom surface of the battery cell. (c) The lead plate is a metal plate that has an L-shape overall and includes an end lead portion that is positioned on the outer surface of the end holder portion and a bottom lead portion that is positioned on the outer surface of the bottom holder portion. (d) The battery pack includes a first locking structure that locks the end lead portion to the end holder portion and a second locking structure that locks the bottom lead portion to the bottom holder portion. (e) The first locking structure allows the end surface lead portion to move freely in the Y-axis direction and prevents positional displacement in the Z-axis direction, and the second locking structure allows the bottom surface lead portion to move freely in the Z-axis direction and prevents positional displacement in the Y-axis direction.

[0008] The above battery pack has the advantage that the lead plates can be simply and easily positioned accurately in the battery holder, and that the lead plates and the end electrodes can be reliably and stably electrically connected.

[0009] 1 is a schematic perspective view of a battery pack including an outer case according to a first embodiment. FIG. 2 is a schematic exploded perspective view of the battery pack of FIG. 1. FIG. 3 is a schematic exploded perspective view of the battery pack of FIG. 1, as viewed from below. FIG. 4 is a schematic perspective view of the battery pack. FIG. 5 is a schematic perspective view of the battery pack before attachment of a first lead-plate. FIG. 6 is a schematic perspective view of the battery pack after attachment of the first lead-plate. FIG. 7 is a schematic perspective view of the battery pack from the first lead-plate side, showing attachment of the first and second lead-plates. FIG. 8 is a schematic perspective view of the battery pack from the second lead-plate side, showing attachment of the first and second lead-plates. FIG. 9 is a schematic bottom view of the battery pack after attachment of the first and second lead-plates. FIG. 10 is a schematic perspective view of an example of attachment of the first lead-plate. FIG. 11 is a schematic perspective view of an example of attachment of the first lead-plate. FIG. 12 is a schematic perspective view of an example of attachment of the second lead-plate. FIG. 13 is a schematic exploded perspective view illustrating the connection of the outer case and the battery holder before storage. FIG. 14 is a schematic perspective view of an example of the outer case and the bottom case. FIG. 15 is a schematic cross-sectional view of the battery pack, as viewed from below. FIG. 10 is a perspective view showing a lead plate and a battery holder of a conventional battery pack.

[0010] The present invention will be described in detail below with reference to the drawings. In the following description, terms indicating specific directions or positions (e.g., "upper," "lower," and other terms incorporating these terms) will be used as necessary. However, the use of these terms is intended to facilitate understanding of the invention with reference to the drawings, and the meaning of these terms does not limit the technical scope of the present invention. Furthermore, parts with the same reference numerals appearing in multiple drawings indicate the same or equivalent parts or components. Furthermore, the embodiments described below are illustrative examples of the technical concept of the present invention and do not limit the scope of the present invention. Furthermore, unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of the components described below are intended for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, the content described in one embodiment or example may also be applicable to other embodiments or examples. Furthermore, the sizes and positional relationships of components shown in the drawings may be exaggerated for clarity.

[0011] The embodiments of the present disclosure may be specified by the following configurations and features. A battery pack according to one embodiment of the present disclosure comprises all of the following configurations (a) to (e): (a) The battery pack comprises a battery cell having an end electrode at its end, a battery holder that positions the battery cell in a fixed position, and a lead plate that is positioned in a fixed position on the battery holder and connected to the end electrode. (b) The battery holder is a molded body that is an integral structure comprising an end surface holder portion that is positioned opposite the end electrode of the battery cell and a bottom surface holder portion that is positioned on the bottom surface of the battery cell. (c) The lead plate is a metal plate that has an L-shape overall and comprises an end surface lead portion that is positioned on the outer surface of the end surface holder portion and a bottom surface lead portion that is positioned on the outer surface of the bottom surface holder portion. (d) The battery pack comprises a first locking structure that locks the end surface lead portion to the end surface holder portion and a second locking structure that locks the bottom surface lead portion to the bottom surface holder portion. (e) The first locking structure allows the end surface lead portion to move freely in the Y-axis direction and prevents positional displacement in the Z-axis direction, and the second locking structure allows the bottom surface lead portion to move freely in the Z-axis direction and prevents positional displacement in the Y-axis direction.

[0012] The above battery packs have the advantage of being able to quickly and accurately position the lead-plates in the battery holder and ensure stable electrical connection between the lead-plates and the end electrodes because the battery packs use unique first and second locking structures to connect the lead-plates to the battery holder. The lead plates are positioned in fixed positions in the battery holder because the first locking structure locks the end lead portions into the end holder portion to position them in fixed positions, the second locking structure locks the bottom lead portions into the bottom holder portion to position them in fixed positions, the first locking structure allows the end lead portions to move freely in the Y axis direction but prevents movement in the Z axis direction to position them in fixed positions on the end holder portion, and the second locking structure allows the bottom lead portions to move freely in the Z axis direction but connects them to the bottom holder portion in a state that prevents positional displacement in the Y axis direction, so that the first and second locking structures prevent positional displacement of the lead plates in directions including the X axis direction, Y axis direction, and Z axis direction, allowing them to be positioned in the battery holder without misalignment. With the above configuration, the second locking structure can prevent positional displacement in the Y axis direction, which is movable by the first locking structure, and the first locking structure can prevent positional displacement in the Z axis direction, which is movable by the second locking structure. The first and second locking structures allow the lead plate to move freely in one direction while preventing the other from shifting. This simple configuration, in which the lead plate is an L-shaped metal plate with end lead portions that engage with the end holder portion and bottom lead portions that engage with the bottom holder portion, has the advantage that the first locking structure for the end lead portions and the second locking structure for the bottom lead portions are positioned at separate positions on a vertical plane (including nearly vertical), effectively preventing misalignment of the lead plate and battery holder in different directions.

[0013] Furthermore, in the above battery pack, the first locking structure allows the end surface holder portion to be freely moved in the Y-axis direction, so the end surface lead portion can be moved in the Y-axis direction and easily connected to the end surface holder portion, and the second locking structure allows it to be freely moved in the Z-axis direction, so the bottom surface lead portion can be moved in the Z-axis direction and connected to the bottom surface holder portion, allowing the L-shaped lead plate to be connected to the battery holder simply and efficiently, and has the advantage of being able to prevent the lead plate from shifting in directions including the Y-axis and Z-axis directions.

[0014] In another embodiment of the battery pack of the present disclosure, in the above aspect, the first locking structure has a first locking portion provided on the end lead portion and a first locked portion provided on the end holder portion, the first locking portion is connected to the first locked portion, allowing the end lead portion to move freely in the Y-axis direction and preventing misalignment in the Z-axis direction, and connecting the end lead portion to the end holder portion; the second locking structure has a second locking portion provided on the bottom lead portion and a second locked portion provided on the bottom holder portion, the second locking portion is connected to the second locked portion, allowing the bottom lead portion to move freely in the Z-axis direction and preventing misalignment in the Y-axis direction, and connecting the bottom lead portion to the bottom holder portion. The above configuration has the advantage of preventing misalignment of the lead plate in directions including the Z-axis and Y-axis directions, allowing for simple and easy accurate positioning of the battery holder. In the above configuration, the first locking structure connects the first locking portion and the first locked portion, and the second locking structure connects the second locking portion and the second locked portion, so that the second locking structure can prevent misalignment in the Y-axis direction, in which the first locking structure is movable, and the first locking structure can prevent misalignment in the Z-axis direction, in which the second locking structure is movable.The above configuration has the first locking portion and the first locked portion provided on the end-face lead portion and the end-face holder portion, and the second locking portion and the second locked portion provided on the bottom lead portion and the bottom holder portion, and is arranged at a distance from each other on a vertical plane (including approximately vertical), which has the advantage of effectively preventing misalignment of the lead plate and the battery holder in different directions.

[0015] In another embodiment of the battery pack of the present disclosure, in any of the above aspects, the first locking portion is an insertion protrusion, the first locked portion is a locking hole into which the insertion protrusion is inserted, and the first locking structure allows the end-face lead portion to move freely in the Y-axis direction and prevents misalignment in the Z-axis and X-axis directions, so that the end-face lead portion can be positioned in a fixed position on the end-face holder portion by the locking structure when the insertion protrusion is inserted into the locking hole.The above configuration has the advantage that, with a simple configuration in which the insertion protrusion is inserted into the locking hole, misalignment of the lead plate in directions including the Z-axis and X-axis directions is prevented, allowing for simple and easy accurate positioning of the battery holder.The above configuration positions the first locking structure on the insertion side by inserting the insertion protrusion into the locking hole, preventing misalignment of the entire lead plate in the Z-axis direction and preventing misalignment in the X-axis direction.

[0016] In another embodiment of the battery pack of the present disclosure, in any of the above aspects, the insertion protrusions are arranged on the outer peripheral edge of the end-face lead portions, and the locking holes are arranged on a peripheral rib arranged along the outer peripheral edge of the end-face holder portion, and the insertion protrusions are inserted into the locking holes, so that the first locking structure allows the end-face lead portions to move freely in the Y-axis direction and prevents misalignment in the Z-axis direction. This configuration has the advantage that, with a simple configuration in which the insertion protrusions are inserted into the locking holes in the peripheral rib, misalignment of the lead plate in directions including the Z-axis direction can be prevented, allowing for simple and easy accurate positioning of the battery holder. By inserting the insertion protrusions into the locking holes in the peripheral rib, the first locking structure on the insertion side can be positioned, preventing misalignment of the entire lead plate in the Z-axis direction and further preventing misalignment in the X-axis direction.

[0017] In another embodiment of the battery pack of the present disclosure, in any of the above aspects, the second locking portion is a slide convex portion provided on a side edge of the bottom lead portion, the second locked portion is a slide groove provided on the bottom holder portion that guides and locks the slide convex portion movably in the Z-axis direction, the slide convex portion is inserted into the slide groove, and the second locking structure allows the bottom lead portion to move freely in the Z-axis direction and prevents positional displacement in the Y-axis direction, so that the bottom lead can be positioned in a fixed position on the bottom holder portion. The above configuration has the advantage that the second locking structure, which has a simple configuration that guides and locks the slide convex portion into the slide groove, can effectively prevent positional displacement of the bottom lead in the Y-axis direction on the locking side.

[0018] In another embodiment of the battery pack of the present disclosure, in any of the above aspects, the end surface lead portions have positioning holes, and the end surface holder portion has positioning protrusions that are inserted into the positioning holes, and the positioning protrusions are inserted into the positioning holes, so that the end surface lead portions are movable in the Z-axis direction and can be positioned in a fixed position on the bottom surface holder portion while preventing positional deviations in the X-axis and Y-axis directions. The above configuration has the advantage that the simple configuration of inserting the positioning protrusions into the positioning holes can effectively prevent positional deviations of the lead plates in directions including the X-axis and Y-axis directions.

[0019] In another embodiment of the battery pack of the present disclosure, in any of the above aspects, the bottom lead portion has a positioning recess at its leading edge in the Z-axis direction, the bottom holder portion has a stopper rib that is inserted into the positioning recess, and the stopper rib is guided by the positioning recess, so that the bottom lead portion is movable in the Z-axis direction and can be positioned at a fixed position on the bottom holder portion while preventing misalignment in the X-axis direction. The above configuration has the advantage that the simple configuration of guiding the positioning recess to the stopper rib can effectively prevent misalignment of the lead plate in directions including the X-axis direction.

[0020] In another embodiment of the battery pack of the present disclosure, in any of the above-described aspects, the battery pack includes a circuit board disposed on the outer surface of the bottom holder portion, and the bottom lead portion can be electrically connected to the circuit board. The above configuration has the advantage that the bottom lead portion can be electrically connected to the circuit board disposed in close proximity to the outer surface of the bottom holder portion.

[0021] In another embodiment of the battery pack of the present disclosure, in any of the above aspects, the battery pack may include a connection terminal portion formed by the bottom lead portion protruding from the side edge, and the connection terminal portion may be electrically connected to the surface of the circuit board. The above configuration has the advantage that the connection terminal portion having a shape protruding from the side edge of the bottom lead portion expands the connectable area, allowing the connection terminal portion to be electrically connected to the circuit board at a predetermined position of the bottom holder portion.

[0022] In another embodiment of the battery pack of the present disclosure, in any of the above aspects, the battery holder has a plurality of battery cells arranged in fixed positions in a parallel orientation, and bottom leads are arranged on both sides of a circuit board arranged on the outer surface of the battery holder, and the connection terminals can be electrically connected to the circuit board. This configuration has the advantage that two or more bottom leads can be arranged on both sides of the circuit board, and the connection terminals of each bottom lead can be electrically connected stably and reliably to the circuit board.

[0023] In a battery pack according to another embodiment of the present disclosure, in any of the above aspects, the end surface lead portions can be laser welded to the end electrodes of the battery cells. With the above configuration, the lead plates can be locked into the battery holder and positioned accurately without misalignment, and then laser welded to the end electrodes, ensuring a reliable and stable electrical connection between the lead plates and the end electrodes. (Embodiment 1)

[0024] 1 to 17 show a battery pack 100 according to a first embodiment. The battery pack 100 includes a battery cell 1, a battery holder 10 that holds the battery cell 1 in a fixed position, lead plates 20 that are set in a fixed position in the battery holder 10 and connected to the end electrodes 2 of the battery cell 1, and a circuit board 5 that is placed on the bottom of the battery cell 1 and connected to the battery cell 1 via the lead plates 20. The battery pack 100 shown in FIGS. 1 to 3 also includes an outer case 6, which houses the battery cell 1, battery holder 10, lead plates 20, and circuit board 5 in an integrated structure. The battery pack 100 with the outer case 6 has the advantage of being easily detachable from a portable device or the like. However, the battery pack 100 of the present disclosure does not necessarily need to include the outer case 6, and the battery cell 1, battery holder 10, lead plates 20, and circuit board 5 can also be integrated and built into an electrical device or the like.

[0025] The battery pack 100 shown in Figures 1 to 4 has cylindrical battery cells 1 arranged in two parallel rows in fixed positions in a battery holder 10. The battery cells 1 are preferably lithium-ion batteries, which allow for a large charge / discharge capacity relative to weight and volume. However, the battery pack 100 of the present disclosure does not limit the battery cells 1 to cylindrical lithium-ion batteries, and all other secondary batteries currently in use and those yet to be developed, such as all-solid-state batteries, can also be used. Furthermore, instead of cylindrical batteries, batteries with shapes other than cylindrical, such as prismatic batteries, can also be used for the battery cells 1.

[0026] The battery pack 100 is assembled by placing the battery cells 1 and lead plates 20 in their designated positions in the battery holder 10, placing a circuit board 5 on the bottom surface of the battery holder 10, and connecting the ends of the lead plates 20 to the end electrodes 2 of the battery cells 1 and the circuit board 5. In the process of connecting the lead plates 20 to the end electrodes 2 of the battery cells 1, the lead plates 20 are positioned accurately on the end electrodes 2 to ensure a reliable and stable electrical connection between them. Misalignment between the lead plates 20 and the end electrodes 2 relative to each other can hinder a reliable and stable electrical connection between them. In the battery pack 100, the battery cells 1 are positioned in their designated positions in the battery holder 10, and the lead plates 20 are positioned accurately on the battery holder 10 to prevent relative misalignment between the end electrodes 2 and the lead plates 20. Furthermore, a structure is required that allows the lead-plates 20 to be quickly, easily, and in place in the battery holder 10 while preventing relative misalignment during the assembly process of the battery pack 100. This is because a structure that requires complicated assembly takes a long time, making it difficult to assemble quickly and efficiently, and increases manufacturing costs.

[0027] The battery pack 100 has a structure that prevents the lead plates 20 from shifting relative to the battery holder 10 while allowing the lead plates 20 to be easily inserted into the battery holder 10. The battery holder 10 and lead plates 20 have one or more projections, locks, or fitting shapes and structures, each of which prevents the lead plates 20 from shifting in a specific direction, allowing them to be positioned in a fixed position on the battery holder 10. In particular, the battery pack 100, which has multiple projections, locks, or fitting shapes and structures, achieves the advantage of preventing the lead plates 20 from shifting, allowing the lead plates to be simply and easily positioned accurately on the battery holder, and ensuring a reliable and stable electrical connection between the lead plates 20 and the end electrodes 2.

[0028] The battery holder 10 shown in the exploded perspective views of Figures 2 and 3 has an end-face holder section 11 positioned opposite the end electrode 2 of the battery cell 1, and a bottom-face holder section 12 attached to the bottom of the battery cell 1, forming an integrated structure of the end-face holder section 11 and bottom-face holder section 12. This battery holder 10 is molded integrally from plastic, allowing for efficient mass production. The battery holder 10 shown in these figures arranges the battery cells 1 in two parallel rows, and has two parallel rows of upward-opening mating grooves that guide each battery cell 1 into its designated position. The top surfaces of the mating grooves are curved to fit the outer periphery of the cylindrical battery, positioning the cylindrical battery in its designated position. Furthermore, the bottom surfaces of the mating grooves have double-sided adhesive tape attached to them, which secures the cylindrical battery in place. The battery holder 10 described above secures the battery cell 1 in place using double-sided adhesive tape, but the battery holder 10 can also be positioned in place using a fitting structure that prevents the battery cell 1 from moving without using double-sided adhesive tape. Furthermore, the battery holder 10 shown in the figure is provided with a pair of end surface holder portions 11 on both ends of the battery cell 1. The pair of end surface holder portions 11 hold both ends of the battery cell 1 set in the fitting groove, preventing the battery cell 1 from shifting in the longitudinal direction.

[0029] The lead-plate 20 shown in the exploded perspective views of Figures 2 and 3 is a metal plate bent into an L-shape, with one bent piece forming an end lead 23 located on the outer surface of the end holder portion 11 of the battery holder 10, and the other bent piece forming a bottom lead 24 located on the outer surface of the bottom holder portion 12. The lead-plate 20 can be shaped and positioned to match the shape and position of the end electrode 2, battery cell 1, and battery holder 10 to which it is connected. The lead-plate 20 shown in Figures 2 and 3 has a first lead-plate 21 that connects to the end electrode 2 on the sealing plate of the cylindrical battery, and a second lead-plate 22 that connects to the end electrode 2 on the bottom surface of the cylindrical battery's exterior tube. The positive and negative electrodes of the battery cell 1 are connected to the circuit board 5 via the first and second lead-plates 21, 22. The first and second lead plates 21 and 22 in FIG. 2 are each placed in a fixed position on the battery holder 10 to ensure reliable and stable electrical connection to the end electrodes 2 on both end faces of the battery cell 1 .

[0030] 5 to 9, the lead-plate 20 and the battery holder 10 are connected by a first locking structure 30 and a second locking structure 40, and the lead-plate 20 is positioned in a fixed position on the battery holder 10. The first locking structure 30 and the second locking structure 40 have shapes, structures, and portions that allow them to connect, lock, and fit to the lead-plate 20 and / or the battery holder 10. As indicated by X, Y, and Z in Figures 5, 8, etc., the first locking structure 30 is a locking structure that allows the end-surface lead portion 23 to move freely in the Y-axis direction and prevents positional displacement in the Z-axis direction, and the second locking structure 40 is a locking structure that allows the bottom-surface lead portion 24 to move freely in the Z-axis direction and prevents positional displacement in the Y-axis direction, thereby positioning the lead-plate 20 in a fixed position on the battery holder 10 without misalignment. In this disclosure, the X-axis direction, Y-axis direction, and Z-axis direction (including both positive and negative directions) are indicated by the arrows in Figure 1, where the X-axis direction indicates the width direction of the bottom surface of the battery holder 10, the Y-axis direction indicates the vertical direction of the bottom surface of the battery holder 10, and the Z-axis direction indicates the vertical direction of the end surface of the battery holder 10.

[0031] The first locking structure 30 is composed of a first locking portion 31 provided on the end surface lead portion 23 and a first locked portion 33 provided on the end surface holder portion 11. The first locking portion 31 is connected to and locked with the first locked portion 33, allowing the end surface lead portion 23 to move freely in the Y-axis direction and preventing positional deviation in the Z-axis direction, thereby positioning the end surface lead portion 23 in a fixed position on the end surface holder portion 11 by the locking structure. The second locking structure 40 is composed of a second locking portion 41 provided on the bottom surface lead portion 24 and a second locked portion 43 provided on the bottom surface holder portion 12, and the second locking portion 41 is connected to the second locked portion 43, allowing the bottom surface lead 24 to move freely in the Z-axis direction and preventing positional deviation in the Y-axis direction, thereby positioning the bottom surface lead 24 in a fixed position on the bottom surface holder portion 12.

[0032] 5 is an insertion protrusion 32 that inserts a portion of the lead plate 20 into an engagement hole 34, and the first engaged portion 33 is provided on the battery holder 10 and is an engagement hole 34 into which the insertion protrusion 32 is inserted. The first engagement structure 30 inserts the insertion protrusion 32 into the engagement hole 34, allowing the end face lead 23 to move freely in the Y-axis direction (the direction opposite to the arrow in the figure, the negative direction) while preventing positional deviation in the Z-axis direction and X-axis direction, thereby positioning the end face lead 23 in a fixed position on the end face holder part 11. With the insertion protrusion 32 inserted into the engagement hole 34, the first engagement part 31 allows the end face lead 23 to move in the Y-axis direction, which is the opposite direction to the insertion, but the entire end face holder part 11 does not move in the Z-axis direction or the X-axis direction, allowing the end face holder part 11 to be positioned. 5 and 6, the first locking structure 30 preferably has the first locking portion 31 as an insertion convex portion 32 protruding from the upper edge of the end face lead portion 23, and the first locked portion 33 as an locking hole 34 provided in the outer circumferential rib 13 arranged along the outer circumferential edge of the end face holder portion 11, with the insertion convex portion 32 being inserted into the locking hole 34 to position the end face lead portion 23 in a fixed position on the end face holder portion 11. The insertion convex portion 32 provided on the outer circumferential edge of the end face lead portion 23 can have a step or unevenness, and part or all of the protruding portion is inserted into the locking hole 34. The first locking portion 31 abuts, locks, and fits the tip of the insertion convex portion 32 inserted into the locking hole 34, the non-inserted portion on the base side (rear end side) of the insertion convex portion 32, and other parts of the lead plate 20 against the end face holder portion 11, thereby positioning the end face lead portion 23 in a fixed position on the end face holder portion 11. As described above, the first locking portion 31 is positioned so that displacement in the Z-axis and X-axis directions is restricted and it cannot move, but it may also be positioned by allowing some displacement in the Z-axis and X-axis directions.

[0033] The second locking structure 40 has a second locking portion 41 that guides a portion of the lead plate 20 to the second locked portion 43, and a second locked portion 43 that locks the second locking portion 41 on the battery holder 10 side. The second locking portion 41 in Fig. 5 is a slide protrusion 42 that protrudes from the side edge of the bottom lead portion 24, and the second locked portion 43 is a slide groove 44 that is provided on the bottom holder portion 12 and guides the slide protrusion 42 for movement in the Z-axis direction. The second locking structure 40 positions the bottom lead portion 24 in a fixed position on the bottom holder portion 12 without misalignment by inserting the slide protrusion 42 into the slide groove 44, allowing the bottom lead portion 24 to move freely in the Z-axis direction while preventing misalignment in the Y-axis direction. Furthermore, the second locking structure 40 can prevent displacement of the bottom lead 24 in the X-axis direction by inserting the slide protrusion 42 into the slide groove 44. As described above, the second locking portion 41 is positioned so that displacement in the Y-axis and X-axis directions is restricted and no movement occurs, but it may also be positioned by allowing some degree of displacement in the Y-axis and X-axis directions.

[0034] The lead plate 20 in Fig. 5 is a metal plate with an L-shaped end surface lead portion 23 and a bottom surface lead portion 24. The battery pack 100 in Fig. 5 has a first locking structure 30 on the end surface lead portion 23 and a second locking structure 40 on the bottom surface lead portion 24. The end surface lead portion 23 and the bottom surface lead portion 24 are positioned in a vertical position (vertical plane) that includes a substantially vertical position of the L-shaped metal plate, effectively preventing misalignment of the lead plate 20 and the battery holder 10 in different directions. Furthermore, the first locking structure 30 and the second locking structure 40 are positioned at both ends in the Y-axis direction (XY plane), effectively preventing misalignment of the lead plate 20 and the battery holder 10. Furthermore, both the first locking structure 30 and the second locking structure 40 are positioned away from the corners of the L-shaped connecting portion of the battery holder 10. The first and second locking structures 30 and 40 lock and connect the lead-plate 20 and battery holder 10 at multiple points, and by contacting, locking, and connecting at other points in addition to the first and second locking structures 30 and 40, such as the corners of the battery holder and the periphery and center of the lead-plate, the number of locks and connections can be increased, further improving the prevention of misalignment. Figure 5 shows an example of the first lead-plate 21, but the same applies to the second lead-plate 22.

[0035] Furthermore, as shown in the perspective views of Figures 5 and 6, the first lead plate 21 has positioning holes 51 formed in the end surface leads 23, and the first end surface holder portion 11A has positioning protrusions 52 that are inserted into the positioning holes 51. With this structure, the positioning protrusions 52 are inserted into the positioning holes 51, allowing the end surface leads 23 to move freely in the Z axis direction while preventing misalignment in the X and Y axes, thereby positioning them in a fixed position on the end surface holder portion 11. Furthermore, the first lead plate 21 and the second lead plate 22 shown in Figures 5 and 6 have positioning recesses 53 formed on the leading edges of the bottom surface leads 24 in the Z axis direction (negative direction), and the bottom surface holder portion 12 has stopper ribs 54 that are inserted into the positioning recesses 53 and guide the stopper ribs 54. With this structure, the bottom surface leads 24 are movable freely in the Z axis direction while preventing misalignment in the X axis direction, allowing them to be positioned in a fixed position on the bottom surface holder portion 12.

[0036] 7 and 8 has a first lead plate 21 and a second lead plate 22 that are connected to the end electrodes 2 located on both end faces of the battery cell 1. The first and second lead plates 21, 22 are each positioned in a fixed position in the battery holder 10 to ensure reliable and stable electrical connection to the end electrodes 2 on both end faces of the battery cell 1. As shown in Figure 8, the second end face holder portion 11B, where the end face lead portion 23 of the second lead portion 22 is located, has a mating recess 55 on its surface that guides the end face lead portion 23 (second end face lead portion 23B) of the second lead plate 22. The inner shape of the mating recess 55 is slightly larger than the outer shape of the second end face lead portion 23B so that the second end face lead portion 23B fits inside and is prevented from shifting in the X and Y axes. The inner shape of the fitting recess 55 is such that the gap between the second end face lead portion 23B set inside is small, for example 1 mm or less, so that the second end face lead portion 23B can be set in the second end face holder portion 11B without misalignment.

[0037] The first lead-plate 21 and the second lead-plate 22 can have the same configuration and structure. Descriptions of the first lead-plate 21 also apply to the second lead-plate 22, and vice versa, as long as they are not inconsistent with the respective structures, configurations, shapes, and aspects. The same applies to the battery holder 10 (end-surface holder portion 11, bottom-surface holder portion 12). For example, the second lead-plate 22 and battery holder 10 in FIG. 8 have a second locking structure 40, a positioning recess 53, and a stopper rib 54, while the second lead-plate 22 and battery holder 10 on the second lead-plate 22 side in FIG. 16 have a first locking structure 30. Positioning holes 51 and positioning protrusions 52 can also be provided on the second lead-plate 22 side. The shape, arrangement, configuration, and structure of the first lead plate 21, second lead plate 22, and each battery holder 10 can be adjusted, arranged, and changed to match the shape and arrangement of the end electrodes 2 and battery cells 1, and depending on the correspondence and combination of the lead plates 20 and battery holders 10.

[0038] The circuit board 5 is disposed on the outer bottom surface of the bottom holder portion 12 and connects to the lead plates 20 that connect to the end electrodes 2 of the battery cells 1. The lead plates 20 that connect to the circuit board 5 can have connection terminals 25. The connection terminals 25 can be provided protruding from the side edges of the bottom leads 24 and placed on the surface of the circuit board 5, allowing for electrical connection by soldering or other methods. The battery pack 100 shown in Figures 4 and 9 has two rows of battery cells 1 arranged in the battery holder 10, with the lead plates 20 connected to each battery cell 1 located on both sides of the circuit board 5, and the connection terminals 25 of the bottom leads 24 can be electrically connected to both sides of the circuit board 5 by soldering or other methods.

[0039] The lead plate 20 has a connection arm 26 that connects to the end electrode 2 of the battery cell 1. The lead plate 20 can be formed by cutting a metal plate and then bending it to form the connection arm 26. The metal plate that will become the lead plate 20 can be cut along the outer periphery of the connection arm 26 in the area that will become the end surface lead 23 to form the connection arm 26, and then the connection arm 26 can be bent to form the connection arm 26 that connects to the end surface lead 23. The bending can be performed by bending the welding portion 27 provided at the tip of the connection arm 26 into a shape that protrudes toward the surface of the end electrode 2, so that the welding portion 27 is positioned on the surface of the end electrode 2.

[0040] The battery holder 10 has an electrode window 14 in the center of the end surface holder portion 11, which exposes the end electrode 2 to which the connection arm portion 26 is connected. The electrode window 14 is opened at a position that exposes the center of the end electrode 2. The electrode window 14 that exposes the end electrode 2 guides the connection arm portion 26 of the end surface lead portion 23 inward, and the welded portion 27 of the connection arm portion 26 that is connected to the end surface lead portion 23 is positioned on the surface of the end electrode 2.

[0041] In the battery pack 100 described above, the lead plates 20 can be set in the fixed positions of the battery holder 10 in which the battery cells 1 are arranged in the fixed positions, by the following steps.

[0042] The lead plate 20 can be first connected to the battery holder 10 by the first locking structure 30 and then placed in place on the battery holder 10 by the second locking structure 40 . As shown by arrow A in Figure 10, the insertion convex portion 32 of the first locking portion 31 provided on the upper edge of the end face lead portion 23 of the first lead plate 21 is inserted into the locking hole 34, which is the first locked portion 33 provided in the outer peripheral rib 13 of the end face holder portion 11.Then, as shown by arrow B in Figure 11, the slide convex portion 42 of the second locking portion 41 provided on the bottom face lead portion 24 is inserted into the slide groove 44 of the second locked portion 43 provided on the battery holder 10, guiding the stopper rib 54 into the positioning recess 53 provided on the tip edge of the bottom face lead portion 24.Furthermore, the positioning convex portion 52 of the end face holder portion 11 is inserted into the positioning hole 51 of the end face lead portion 23, and the end face lead portion 23 is positioned on the surface of the end face holder portion 11. In this state, the first lead-plate 21 is held in its designated position on the battery holder 10 without misalignment by the first locking structure 30 and the second locking structure 40. Furthermore, the first lead-plate 21 is more reliably held in its designated position on the battery holder 10 without misalignment by the stopper rib 54 on the end face holder part 11 guided by the positioning recess 53 on the end face lead part 23 and the positioning protrusion 52 on the end face holder part 11 inserted into the positioning hole 51 on the end face lead part 23. Once the first lead-plate 21 is set in the battery holder 10 in this state, misalignment in the X-axis and Y-axis directions is prevented by the first locking structure 30, and misalignment in the Z-axis direction is prevented by the second locking structure 40, meaning that misalignment in all directions is prevented and the first lead-plate 21 is positioned in its designated position on the battery holder 10.

[0043] As shown by arrow C in Fig. 12 , the insertion convex portion 32 (first locking portion 31) on the upper edge of the end surface lead portion 23 of the second lead-plate 22 is inserted into the locking hole 34 (first locked portion 33) on the outer peripheral rib 13 of the end surface holder portion 11. Then, as shown by arrow D in Fig. 13 , the slide convex portion 42 (second locking portion 41) on the bottom surface lead portion 24 is inserted into the slide groove 44 (second locked portion 43) on the battery holder 10. The stopper rib 54 is guided into the positioning recess 53 on the tip edge of the bottom surface lead portion 24, and the end surface lead portion 23 is positioned on the surface of the end surface holder portion 11. In this state, the first locking structure 30 and the second locking structure 40 position the second lead-plate 22 in the specified position on the battery holder 10 without any misalignment. Furthermore, the second lead-plate 22 is positioned in a fixed position on the end face holder portion 11 by guiding the end face lead portion 23 into the mating recess 55 provided on the surface of the end face holder portion 11. When the second lead-plate 22 is set in the battery holder 10 in the above state, the mating recess 55 and first locking structure 30 prevent misalignment in the X and Y axes, and the second locking structure 40 prevents misalignment in the Z axis.The second lead-plate 22 is further guided by the mating recess 55 on the end face holder portion 11, preventing misalignment in all directions and positioning it in the fixed position on the battery holder 10.

[0044] The lead-plate 20 and battery holder 10 described above can be electrically connected by positioning the lead-plate 20 in a fixed position on the battery holder 10 using the first locking structure 30 and second locking structure 40, positioning the weld portion 27 of the connection arm 26 on the surface of the end electrode 2 of the battery cell 1, and welding the weld portion 27 to the surface of the end electrode 2 using methods such as laser welding or spot welding. Laser welding and spot welding ensure stable adhesion of the weld portion 27 of the connection arm 26 to the surface of the end electrode 2. Laser welding melts both the weld portion 27 of the connection arm 26 and the end electrode 2 of the battery cell 1 with an irradiated laser beam, while spot welding melts and welds both the weld portion 27 and the end electrode 2 using Joule heat. Therefore, unstable contact between the weld portion 27 and the end electrode 2 can hinder stable welding between the weld portion 27 and the end electrode 2. The structure in which the end surface lead portion 23 can be positioned accurately in the battery holder 10 using both the first retaining structure 30 and the second retaining structure 40 prevents relative positional deviation between the welded portion 27 of the connecting arm portion 26 connected to the end surface lead portion 23 and the end electrode 2 of the battery cell 1 positioned in a fixed position in the battery holder 10, achieving stable contact between the welded portion 27 and the end electrode 2, achieving reliable and stable welding and achieving an ideal electrical connection.

[0045] 14 to 17 , a battery pack 100 is formed by connecting battery cells 1, battery holders 10, lead plates 20, and a circuit board 5 in an integrated structure to form a battery block 3, which can be housed in an exterior case 6. The exterior case 6 illustrated in these figures includes a lid case 6A and a bottom case 6B. The bottom case 6B positions the battery block 3 in a fixed position. The bottom case 6B, which positions the battery block 3 in a fixed position, can be connected to the lid case 6A, allowing the battery block 3 to be positioned in a fixed position inside the exterior case 6.

[0046] In the exploded perspective view of Figure 14 and the cross-sectional views of Figures 16 and 17, a stopper protrusion 7a is provided on the bottom case 6B, and a stopper plate 7b that engages with the underside of this stopper protrusion 7a is provided on the battery holder 10 of the battery block 3. The stopper protrusion 7a protrudes from the inner surface of the peripheral wall 9 of the bottom case 6B, and its underside serves as a locking surface for locking the stopper plate 7b of the battery holder 10. The stopper plate 7b of the battery holder 10 is located in a position where it will engage with the locking surface of the stopper protrusion 7a of the bottom case 6B when the battery block 3 is set in its fixed position in the bottom case 6B. The bottom case 6B and battery block 3 shown in the above figures have multiple stopper protrusions 7a and stopper plates 7b (three locations in Figures 14 and 15) spaced apart in the longitudinal direction of the cylindrical batteries, allowing the battery holder 10 to be positioned in its fixed position in the bottom case 6B. The stopper protrusion 7a shown in Figure 17 has a shape in which the lower surface is a horizontal plane to securely engage the stopper plate 7b, and the inner surfaces other than the lower surface of the stopper protrusion 7a are inclined surfaces, allowing the battery block 3 to be smoothly inserted into the bottom case 6B and set in a fixed position.

[0047] Furthermore, in the outer case 6 illustrated in Figures 16 and 17, in order to inseparably connect the lid case 6A and the bottom case 6B, locking holes 8b are provided in the bottom case 6B, and insertion hooks 8a that engage with the locking holes 8b are provided in the lid case 6A. The bottom case 6B has a double-walled peripheral wall 9 consisting of an inner wall 9X and an outer wall 9Y, and an insertion gap 9Z is provided between the inner wall 9X and the outer wall 9Y to guide the insertion hooks 8a, and the inner wall 9X has locking holes 8b. The lid case 6A has insertion hooks 8a on the inner surface of the lower part of the side wall. In the outer case 6 with this structure, the insertion hooks 8a of the lid case 6A are inserted between the inner wall 9X and the outer wall 9Y of the bottom case 6B, and the insertion hooks 8a engage with the locking holes 8b, allowing the lid case 6A and the bottom case 6B to be inseparably connected. The insertion hooks 8a inserted between the inner wall 9X and the outer wall 9Y are engaged with the upper edges of the locking holes 8b, connecting the lid case 6A and the bottom case 6B in a non-detachable manner. Furthermore, the insertion hooks 8a are sandwiched between the inner wall 9X and the outer wall 9Y and are more securely engaged with the locking holes 8b, connecting the lid case 6A and the bottom case 6B in a non-detachable manner. The outer case 6 shown in Figures 14 and 15 has insertion hooks 8a at eight locations on both side walls, which are the peripheral wall 9 of the lid case 6A, and four locations on the peripheral wall 9 at the end, and the bottom case 6B has locking holes 8b at the locking positions of the insertion hooks 8a, connecting the lid case 6A and the bottom case 6B in a non-detachable manner at multiple locations.

[0048] The battery pack according to the present disclosure can be suitably used as a battery pack in which the lead plates can be simply and easily positioned in the correct position in the battery holder, and the lead plates and the end electrodes can be reliably and stably electrically connected to each other.

[0049] DESCRIPTION OF SYMBOLS 100, 900... Battery pack 1... Battery cell 2... End electrode 3... Battery block 5... Circuit board 6... Outer case 6A... Lid case 6B... Bottom case 7a... Stopper protrusion 7b... Stopper plate 8a... Insertion hook 8b... Locking hole 9... Peripheral wall 9X... Inner wall 9Y... Outer wall 9Z... Insertion gap 10... Battery holder 11... End face holder portion 11A... First end face holder portion 11B... Second end face holder portion 12... Bottom face holder portion 13... Peripheral rib 14... Electrode window 20... Lead plate 21... First lead plate 22... Second lead plate 23... End face lead portion 23B... Second end face lead portion 24... Bottom face lead portion 25... Connection terminal portion 26... Connection arm portion 27... Welded portion 30... First locking structure 31...First locking portion 32...Insertion convex portion 33...First locked portion 34...Lock hole 40...Second locking structure 41...Second locking portion 42...Slide convex portion 43...Second locked portion 44...Slide groove 51...Positioning hole 52...Positioning convex portion 53...Positioning recess 54...Stopper rib 55...Fitting recess 910...Battery holder 920...Lead plate 930...Lock portion

Claims

1. A battery pack comprising all of the following configurations (a) to (e): (a) The battery pack comprises a battery cell having an end electrode at its end, a battery holder that positions the battery cell in a fixed position, and a lead plate that is positioned in a fixed position on the battery holder and connected to the end electrode. (b) The battery holder is a molded body that integrates an end holder portion that is positioned opposite the end electrode of the battery cell and a bottom holder portion that is positioned on the bottom surface of the battery cell. (c) The lead plate is a metal plate that has an overall L-shape and comprises an end lead portion that is positioned on the outer surface of the end holder portion and a bottom lead portion that is positioned on the outer surface of the bottom holder portion. (d) The battery pack comprises a first locking structure that locks the end lead portion to the end holder portion, and a second locking structure that locks the bottom lead portion to the bottom holder portion. (e) The first locking structure is a locking structure that allows the end surface lead portion to move freely in the Y-axis direction and prevents positional displacement in the Z-axis direction, and the second locking structure is a locking structure that allows the bottom surface lead portion to move freely in the Z-axis direction and prevents positional displacement in the Y-axis direction.

2. A battery pack as claimed in claim 1, wherein the first locking structure has a first locking portion provided on the end surface lead portion and a first locked portion provided on the end surface holder portion, the first locking portion being connected to the first locked portion, the end surface lead portion being movable in the Y-axis direction and preventing misalignment in the Z-axis direction, and the end surface lead portion being connected to the end surface holder portion; and the second locking structure has a second locking portion provided on the bottom surface lead portion and a second locked portion provided on the bottom surface holder portion, the second locking portion being connected to the second locked portion, the bottom surface lead portion being movable in the Z-axis direction and preventing misalignment in the Y-axis direction, and the bottom surface lead portion being connected to the bottom holder portion.

3. A battery pack as claimed in claim 2, wherein the first locking portion is an insertion convex portion, the first locked portion is a locking hole into which the insertion convex portion is inserted, and the first locking structure is such that the insertion convex portion is inserted into the locking hole, the end face lead portion is movable in the Y-axis direction, and positional deviation in the Z-axis and X-axis directions is prevented, and the end face lead portion is positioned in a fixed position on the end face holder portion by the locking structure.

4. A battery pack as claimed in claim 3, wherein the insertion protrusion is arranged on the outer peripheral edge of the end face lead portion, the locking hole is arranged on an outer peripheral rib arranged along the outer peripheral edge of the end face holder portion, the insertion protrusion is inserted into the locking hole, and the first locking structure allows the end face lead portion to move freely in the Y-axis direction and prevents positional displacement in the Z-axis direction.

5. A battery pack as described in claim 2, wherein the second locking portion is a slide convex portion provided on the side edge of the bottom lead portion, the second locked portion is a slide groove provided on the bottom holder portion and guiding and locking the slide convex portion so that it can move freely in the Z-axis direction, the slide convex portion being inserted into the slide groove, and the second locking structure allows the bottom lead portion to move freely in the Z-axis direction and prevents positional deviation in the Y-axis direction, thereby positioning the bottom lead portion in a fixed position on the bottom holder portion.

6. A battery pack as claimed in claim 1, wherein the end face lead portion is provided with a positioning hole, the end face holder portion is provided with a positioning protrusion that is inserted into the positioning hole, and when the positioning protrusion is inserted into the positioning hole, the end face lead portion is movable in the Z-axis direction and is prevented from shifting in the X-axis and Y-axis directions, and is positioned in a fixed position on the end face holder portion.

7. A battery pack as claimed in claim 1, wherein the bottom lead portion has a positioning recess at its leading edge in the Z-axis direction, the bottom holder portion has a stopper rib that is inserted into the positioning recess, and the stopper rib is guided by the positioning recess, so that the bottom lead portion is movable in the Z-axis direction and is prevented from shifting in the X-axis direction, and is positioned in a fixed position on the bottom holder portion.

8. A battery pack according to claim 1, comprising a circuit board disposed on the outer surface of said bottom holder, said bottom lead portion being electrically connected to said circuit board.

9. A battery pack according to claim 8, wherein the bottom lead portion has a connection terminal portion protruding from a side edge, and the connection terminal portion is electrically connected to the surface of the circuit board.

10. A battery pack as claimed in claim 9, wherein the battery holder has a plurality of the battery cells arranged in fixed positions in a parallel posture, the bottom lead portions are arranged on both sides of the circuit board arranged on the outer surface of the battery holder, and the connection terminal portions are electrically connected to the circuit board.

11. A battery pack according to any one of claims 1 to 10, wherein the end surface lead portion is laser welded to the end electrode of the battery cell.

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