JP5546885B2 - Battery pack - Google Patents

Description

  The present invention relates to a battery pack containing a plurality of rechargeable unit cells, and more particularly to a battery pack whose outer shape can be reduced.

  For applications that require a large current for driving, such as electric bicycles and assist bicycles, battery packs are used in which multiple unit cells are connected in series to increase the output voltage and connected in parallel to increase the output current. . In particular, there is a need for a battery pack that can meet the recent demand for higher output and the demand for smaller size and light weight that are easy to carry. On the other hand, increasing the output current tends to increase the amount of heat generated by the unit cells, switching elements such as FETs that control the discharge, and electronic components such as diodes, so that they can be used stably over a long period of time. A heat dissipation structure is required.

JP 2008-34296 A

  However, the more you try to reduce the size of the battery pack, the more easily heat is trapped inside and the heat dissipation becomes worse.In addition, the addition of a heat dissipation mechanism increases the size of the outer shape. Contradictingly, it is not easy to achieve both.

  In addition, in a structure in which a large number of unit cells are connected in series, the larger the number of unit cells, the heavier and heavier it becomes, and there is a problem that it is bulky at the part stage and is not easy to handle during assembly.

  On the other hand, since a battery pack used for a moving body such as a bicycle is exposed to vibration and impact, it needs to have sufficient mechanical strength. For example, if the lead plates of the unit cells connected in series are detached due to vibration or impact, or if contact failure occurs, the entire battery pack cannot be used.

  On the other hand, there is a strong demand for cost reduction, and it is necessary to increase mechanical strength with as simple a structure as possible, secure heat dissipation and maintain reliability over a long period of time. There is an ongoing demand for improvements in battery packs that can be satisfied.

  The present invention has been made in view of such demands, and its main object is to provide a battery pack that is easy to assemble while reducing the size and simplification of the battery pack while maintaining reliability. There is.

Means for Solving the Problems and Effects of the Invention

  In order to achieve the above object, according to the first battery pack of the present invention, a plurality of unit cells 11 having a cylindrical outer can and a battery for holding the plurality of unit cells 11 in a posture parallel to each other. A plurality of battery blocks 10 constituted by spacers 12 and for each battery block 10, the end faces of the unit cells 11 held by the battery spacer 12 are connected to connect the unit cells 11 in parallel, A lead plate 20 that connects adjacent battery blocks 10 in series, a circuit board 40 that is electrically connected to the lead plate 20, and an exterior housing the battery block 10 and the circuit board 40 therein. A battery pack including a case 30, wherein the battery blocks 10 are parallel to each other such that end faces of the unit cells 11 included in the battery block 10 are substantially in the same plane. The battery assembly 1 is a solid battery block stage 2, which is stacked so that a plurality of the battery block stages 2 are arranged in a substantially straight line in the longitudinal direction of the cylindrical shape so that the end faces of the unit cells 11 face each other. For each battery block stage 2 that is stacked and adjacent, the lead plate 20 is extended to the side surface side of the battery assembly 1 and the extended portions of the lead plate 20 are electrically connected to each other. A lead connection portion 25 for connecting the lead plates 20 by alternately changing the side surfaces of the battery assembly 1 between adjacent battery block stages 2. Can do. As a result, the battery block stages are connected in a zigzag manner at the lead connection portion to increase the number of series connections, thereby achieving higher output, and a lead connection portion for connecting the lead plates to each other is prepared as a separate member. It is possible to avoid the situation that the steps are enlarged, and to obtain the advantages that the assembly efficiency of the battery pack can be improved.

Further, according to the second battery pack, the lead connection portion 25 is a metal flat plate connecting a pair of fixing pieces 26 having screw holes and the thickness of the flat plate is larger than that of the lead plate 20. The lead plate 20 includes a lead connection terminal 22 bent in an L shape along the side surface of the battery block stage 2, and the lead connection terminal is a connection terminal screw. A hole 23 is opened, the battery spacer 12 opens a screw receiving portion on a side surface of the battery assembly 1, and the lead connection portion 25 is connected to the lead connection terminal 22 and the battery spacer 12. The lead connection screw 28 can be fixed by screwing. Thus, the lead plates can be electrically connected to each other by screwing alternately on the side surface of the battery assembly. At the same time, by connecting the battery spacers at the lead connection portion of the metal plate, the mechanical connection between the battery spacers can be maintained.

  Further, according to the third battery pack, the lead connecting portion 25 is a bent piece in which a part of the lead plate 20 protrudes from the upper surface of the battery assembly 1 and is bent in an L shape. Adjacent lead plates 20 can be connected to each other by overlapping and screwing the bent pieces. Thereby, even if it does not utilize the lead connection part of another member, a part of lead board can be bent and it can utilize as a lead connection part, and the advantage which can reduce manufacturing cost is acquired.

  Further, according to the fourth battery pack, the battery spacer 12 is held in a posture in which the plurality of unit cells 11 are stacked in two stages and are parallel to each other, and along the cylindrical surface of the unit cell 11. The curved battery holding surface 13 can be opened up and down. Thereby, the cylindrical unit cells can be held on the upper and lower surfaces of the battery spacer, respectively, and the shape of the battery spacer can be simplified and easily manufactured.

  Furthermore, according to the fifth battery pack, the battery case 12 further includes a plurality of metal through screws 50 penetrating the battery assembly 1 in parallel in the length direction of the outer case 30, and the battery spacer 12 includes The battery spacer 12 is made of an insulative resin, and the center axis of the battery holding surface 13 that is opened up and down is substantially aligned with a straight line, and between the four battery holding surfaces 13 adjacent to each other. A spacer through hole 14 for inserting the through screw 50 can be opened in at least one of them. As a result, when the semi-cylindrical battery holding surfaces are arranged in a matrix, spacer through holes are opened in the dead space generated between them, and the space is effectively used to achieve miniaturization, and the battery A battery pack that can be used for prevention of shrinkage at the time of resin curing when the spacer is resin-molded and for stealing meat can be realized in terms of manufacturing cost. In addition, since the entire battery assembly can be fixed with a plurality of through screws, its mechanical strength and reliability are dramatically improved compared to the conventional connection between battery blocks only, especially vibration and shock from the outside. A battery pack having resistance to the above can be configured. In particular, by passing a metal through screw between four adjacent unit cells, heat conduction is improved by passing the metal through screw through an area where heat is likely to accumulate, and the generated heat is passed through the through screw. It can be conducted to the end face of the outer case to radiate heat from the end face, and improvement in heat dissipation can be expected.

  Furthermore, according to the sixth battery pack, the plurality of through screws 50 can be disposed so as to penetrate each battery block 10 constituting the battery block stage 2. Thereby, since all the battery blocks are penetrated by the through screws, it is possible to surely improve the connection strength of the battery assembly.

  Furthermore, according to the seventh battery pack, an insulating insulating sheet 35 is further disposed between the battery block stages 2 to insulate and insulate between the opposing lead plates 20. Thus, a sheet through hole 36 for inserting the through screw 50 can be opened in the insulating sheet 35. As a result, it is possible to effectively insulate by interposing the insulating sheet between the opposing lead plates, and to achieve positioning and holding of the insulating sheet by opening the sheet through hole and passing the through screw. Effects can also be obtained.

  Furthermore, according to the eighth battery pack, the battery spacer 12 includes a spacer connecting portion 16 for connecting to another battery spacer 12 constituting the battery block stage 2, and the spacer connecting portion 16 The battery spacer 12 can be disposed between the upper and lower battery holding surfaces 13 on the side surface. Thereby, while arranging a spacer connection part in the dead space between battery holding surfaces and aiming at effective use of a space, the battery block which connected battery blocks by connecting battery spacers via a spacer connection part The stage can be easily configured.

  Furthermore, according to the ninth battery pack, the battery spacer 12 is a side surface of the battery assembly 1, and a connection groove 17 is opened between the upper and lower battery holding surfaces 13. By inserting the spacer connecting portion 16 into the adjacent battery spacers 12, the adjacent battery spacers 12 can be mechanically connected. As a result, the connecting structure is arranged in the dead space between the battery holding surfaces so that the space can be used effectively, and the battery spacers can be connected with a simple configuration, so that the battery block stage connecting the battery blocks can be easily performed. Can be configured.

  Furthermore, according to the tenth battery pack, the connecting groove 17 can also be used as a screw receiving portion. As a result, the battery spacer has a connection groove provided on the side surface as a connection groove connected to the spacer connection portion on the side surface connected to other battery spacers, and as a screw receiving portion when it becomes the side surface of the battery block step. The advantage of being able to function and simplifying the configuration is obtained.

  Furthermore, according to the eleventh battery pack, a part of the plurality of through screws 50 can also be used as a conductive lead. As a result, the metal through screw can be used not only for the purpose of reinforcement but also as a conductive lead, which can reduce the number of parts and contribute to size reduction and cost reduction.

  Furthermore, according to the twelfth battery pack, the battery assembly 1 is configured such that the battery block stage 2 located on the end face is configured with the battery blocks 10 that are fewer than the other battery block stages 2 to form an empty space BS. In addition, the output terminal 33 can be arranged in the empty space BS. Thereby, since an output terminal can be arrange | positioned using the empty space of a battery block, the internal space of an exterior case can be used efficiently and it can contribute to size reduction of the whole shape.

  Furthermore, according to the thirteenth battery pack, the battery block 10 uses the three unit cells 11, and the battery assembly 1 is configured by connecting the three battery blocks 10. The battery block stage 2A may be connected in four stages, and a second battery block stage 2B configured by connecting two battery blocks 10 to the end face may be connected in one stage. Thereby, the battery pack which connected 14 unit cells in series can be comprised, and an empty space can be formed in the end surface of a battery assembly simultaneously.

  Furthermore, according to the fourteenth battery pack, the output voltage of the battery pack can be set to 48V. Thereby, the battery pack which can supply the voltage of 48V utilized for many uses is realizable.

It is a perspective view which shows the battery pack which concerns on embodiment. It is a top view of the battery pack of FIG. It is a longitudinal cross-sectional view in the III-III line of FIG. FIG. 4 is a transverse sectional view taken along line IV-IV in FIG. 2. FIG. 3 is a plan view showing a state where an outer case is removed from the battery pack of FIG. 2. It is a disassembled perspective view which shows the state which removed the 1st end surface plate from the battery pack of FIG. It is a disassembled perspective view of the battery pack of FIG. It is the disassembled perspective view which looked at the battery pack of FIG. 7 from the back side. It is a disassembled perspective view which shows the lead plate of the end surface of the battery assembly of FIG. It is a disassembled perspective view which shows the state which connects a lead board to a battery block stage. FIG. 10 is an exploded perspective view showing a state in which battery block stages of the battery assembly of FIG. 9 are connected. It is a disassembled perspective view which shows the state which connects the battery block stage of the battery assembly seen from another angle. It is a disassembled perspective view which shows the state which connects a battery block stage by a lead connection part. It is sectional drawing which shows the state which fixes a battery block step with a penetration screw. It is a perspective view which shows the part of the 1st end surface cover which fastens a penetration screw. It is a perspective view which shows the part of the 2nd end surface cover which fastens a penetration screw. It is a schematic diagram which shows the connection state of the unit cell which comprises the battery assembly of FIG. It is a perspective view of a battery block. It is a perspective view of a battery spacer. It is a perspective view which shows the state which connects battery spacers. It is sectional drawing which shows the state which connected battery spacers. It is a perspective view which shows the lead connection part which concerns on a modification.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiment described below exemplifies a battery pack for embodying the technical idea of the present invention, and the present invention does not specify the battery pack as follows. Further, in the present specification, in order to facilitate understanding of the scope of claims, numbers corresponding to the members shown in the embodiments are indicated in the “claims” and “means for solving problems” sections. It is appended to the members shown. However, the members shown in the claims are not limited to the members in the embodiments. In particular, the dimensions, materials, shapes, relative arrangements, and the like of the constituent members described in the embodiments are not intended to limit the scope of the present invention only to the description unless otherwise specified. It's just an example. Note that the size, positional relationship, and the like of the members shown in each drawing may be exaggerated for clarity of explanation. Furthermore, in the following description, the same name and symbol indicate the same or the same members, and detailed description thereof will be omitted as appropriate. Furthermore, each element constituting the present invention may be configured such that a plurality of elements are constituted by the same member and the plurality of elements are shared by one member, and conversely, the function of one member is constituted by a plurality of members. It can also be realized by sharing. In addition, the contents described in some examples and embodiments may be used in other examples and embodiments.
(Embodiment 1)

  Based on FIGS. 1-22, the example applied to the power supply apparatus for assist bicycles as a battery pack which concerns on embodiment of this invention is demonstrated. In these drawings, FIG. 1 is a perspective view showing a battery pack 100 according to the embodiment, FIG. 2 is a plan view of the battery pack 100 in FIG. 1, and FIG. 3 is a longitudinal sectional view taken along line III-III in FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 2, FIG. 5 is a plan view showing a state where the outer case 30 is removed from the battery pack 100 in FIG. 2, and FIG. 6 is a first end face table from the battery pack 100 in FIG. FIG. 7 is an exploded perspective view of the battery pack 100 of FIG. 1, FIG. 8 is an exploded perspective view of the battery pack 100 of FIG. 7 viewed from the back side, and FIG. 10 is an exploded perspective view showing the lead plate 20 on the end face of the battery assembly 1, FIG. 10 is an exploded perspective view showing a state in which the lead plate 20 is connected to the battery block stage 2, and FIG. 11 is a battery of the battery assembly 1 in FIG. The exploded perspective view which shows the state which connects the block stage 2, FIG. The exploded perspective view which shows the state which connects the battery block stage 2 of the battery assembly 1 seen from the angle of FIG. 13, FIG. 13 is the exploded perspective view which shows the state which connects the battery block stage 2 with the lead connection part 25, FIG. FIG. 15 is a perspective view showing a part of the first end face cover 31 for fastening the through screw 50, and FIG. 16 is a second end face cover for fastening the through screw 50. FIG. FIG. 17 is a schematic view showing a connection state of the unit cells 11 constituting the battery assembly 1 of FIG. 9, FIG. 18 is a perspective view of the battery block 10, and FIG. 19 is a perspective view of the battery spacer 12. 20 is a perspective view showing a state in which the battery spacers 12 are connected to each other, FIG. 21 is a sectional view showing a state in which the battery spacers 12 are connected together, and FIG. 22 is a perspective view showing a lead connecting portion 25 according to a modification. Respectively To have.

A battery pack 100 shown in these drawings includes a battery assembly 1 to which a plurality of unit cells 11 are connected, a circuit board 40 connected to the unit cells 11, and an outer case 30 that houses them inside. . In the battery pack 100 according to the first embodiment, a plurality of unit cells 11 are held in a horizontal posture by a battery spacer 12 to form a battery block 10, and the battery blocks 10 are connected in the lateral direction to form a battery block stage 2. Further, the battery assembly 1 is configured by connecting the battery block stages 2 in the vertical direction. 7, 8, 9, 17, etc., three battery blocks 10 are connected in the lateral direction to form a battery block stage 2, and further five battery block stages 2 are connected to form a battery assembly. 1 is configured. However, only the leftmost battery block stage 2 in FIG. 5 and FIG. 7 connects two battery blocks 10 and forms an empty space BS by one battery block less than the others. Each battery block 10 has three unit cells 11 stacked vertically in two rows, and a total of six unit cells 11 are connected in parallel. As a result, in the entire battery assembly, 14 unit cells 11 are connected in series, and the output voltage is adjusted to 48V. Since the output voltage of 48V is used in many applications, there is an advantage that it can be applied as it is to a wide range of applications.
(Exterior case 30)

As shown in FIGS. 1 to 5, the outer case 30 is formed in a thin box shape having a width wider than the thickness. Moreover, as shown in FIGS. 6-8, it is set as the box shape which opened the end surface of both sides, and the battery assembly 1, the circuit board 40, etc. can be inserted in an inside from an opening part. The outer case 30 has two main surfaces facing each other as a large area, and serves as a heat radiating surface that releases heat generated in the internal battery assembly 1 and the circuit board 40 to the outside. In addition, heat dissipation may be improved by providing irregularities 30F (see FIGS. 1 to 2 and 4), fins, and the like on the surface of the main surface to further increase the surface area. The exterior case 30 is made of aluminum having excellent heat dissipation and strength. In addition, in order to insulate a metal outer case such as aluminum, the surface may be covered with a laminate film or vinyl.
(Cross section cover)

Further, both end surfaces of the outer case 30 are closed with end surface plates. In the example of FIG. 7, the left opening end face is closed with the first end face surface plate 31H and the right opening end face is closed with the second end face surface plate 32H, and the end face surface plate is fixed to the exterior case 30 with screws or the like. Further, a first end surface cover 31 is arranged inside the first end surface plate 31H as shown in FIG. 6, and similarly, inside the second end surface plate 32H, as shown in FIGS. As shown, the second end surface covers 32 are respectively disposed. The first end surface cover 31 includes an output terminal 33 for taking out the power output to the outside. It should be noted that the second end face surface plate may be omitted, and the exterior case may be configured as a bottomed box having only one end face opened, and the end face opening may be closed only by the first end face face plate. Absent.
(Battery assembly 1)

  As shown in FIGS. 7 to 8 and the like, the battery assembly 1 is inserted into the outer case 30. A circuit board 40 is disposed on one side surface of the battery assembly 1. On the circuit board 40, a protection circuit for protecting the unit cell 11 from overdischarge or overcharge, a charge / discharge circuit, or the like is mounted as necessary.

  As shown in the longitudinal sectional view of FIG. 3 and the transverse sectional view of FIG. 4, the battery assembly 1 has two unit cells 11 stacked one above the other. With such a configuration, each of the unit cells 11 can have the side surface of the cylindrical outer can facing the main surface of one of the two outer casings 30, so that it directly conducts heat to the outer casing 30. And has the advantage of easy heat dissipation. In other words, by not stacking three or more unit cells, there is an advantage that the unit cells that do not face the outer case are eliminated and each unit cell can be cooled uniformly.

In this example, the unit cells 11 are placed in a horizontal posture by the battery spacer 12, and further, the unit cells 11 are arranged along the length direction of the outer can, and the valleys between the unit cells 11 arranged horizontally can be continued. That is, as shown in FIG. 3 and the like, the battery block 10 is connected not only in the lateral direction but also in the length direction of the unit cells 11, so that the integrity of the battery assembly 1 can be increased. . This also leads to effective use of the space. Also, between the upper and lower unit cells 11, the cylindrical unit cells 11 are arranged in a matrix with the center axes aligned. In other words, a space is intentionally created between the unit cells by not arranging the cylindrical unit cells in an offset or staggered arrangement that is eccentric so that the central axes do not coincide with each other.
(Spacer through hole 14)

  In particular, the dead space generated by this matrix arrangement is used as the spacer through hole 14 of the through screw 50 that penetrates the entire battery assembly 1 as shown in the sectional view of FIG. In addition, the strength of the battery assembly 1 itself can be improved. In particular, in the conventional battery pack, it is often the case that only the interface between the battery blocks is connected and a mechanism for penetrating and holding the entire battery block is not provided. For this reason, mechanical strength is also important in applications exposed to vibration and impact, such as battery packs for moving bodies such as assist bicycles. Even if the outer case is a strong metal case, if the connection strength of the internal battery assembly is insufficient, there is a possibility of contact failure or disconnection due to dislocation or displacement of the battery blocks inside the outer case. Considering this, it can be said that it is preferable to provide a structure that penetrates and fixes the entire battery assembly.

  However, in order to provide such a mechanism for penetrating and fixing the whole, a space for providing a screw hole has to be prepared, which causes a problem that the battery pack becomes thick. Therefore, in the present embodiment, in the battery pack using a cylindrical unit cell, an arrangement in which a dead space is intentionally employed is adopted, while the dead space is used for the spacer through hole 14 for the through screw 50, thereby providing a battery. The situation where the pack becomes thicker than necessary can be avoided. In particular, in the battery assembly of this configuration, since the unit cells 11 are stacked in two stages, the space between the unit cells inevitably becomes substantially the center in the thickness direction of the battery pack 100, and therefore the position where the through screw 50 is provided. As a convenience. Furthermore, by using the through screw 50 as a metal screw, the through screw 50 can also be used as a heat conduction medium. That is, in the region where the four unit cells are in contact with each other, heat is likely to be trapped. By passing through this portion a metal through screw 50 having excellent heat conduction, the generated heat is conducted through the through screw 50. It travels to the end face of the battery assembly and can be discharged from here through the end face of the outer case. For this reason, there is obtained an advantage that the through screw 50 can be used not only for improving the mechanical strength but also for improving the heat dissipation.

In addition, as shown in the cross-sectional view of FIG. 21, a resin through-hole 14 is provided at a cross-shaped position between the four battery holding surfaces 13 on which the unit cells 11 are arranged at the center of the battery spacer 12. Thus, the battery spacer 12 can be used for preventing the shrinkage when the resin is cured and for stealing the meat, and the amount of the resin material required for the battery spacer molding is reduced, which is advantageous in terms of manufacturing cost.
(Through screw 50)

  A plurality of through screws 50 are provided in the length direction of the outer case 30 so as to penetrate the battery assembly 1 in parallel. 9 to 16, in the battery block stage 2 in which the three battery blocks 10 are connected in the lateral direction, the three through screws 50 penetrate the battery assembly 1 so as to penetrate each battery block 10. It is arranged as follows. That is, since each battery block row 3 is penetrated by the penetration screw 50, all the battery blocks 10 are securely fixed, and the battery assembly 1 can be firmly fixed integrally. The through screw 50 is made of metal excellent in strength and heat conduction. Further, the length is designed so as to penetrate the battery assembly 1 in parallel with the length direction of the outer case 30. In the example of FIG. 14, the lower two first through screws 50 </ b> A are long enough to penetrate five battery block rows 3, and the upper one second through screw 50 </ b> B is long enough to penetrate four battery block rows 3. To do.

The battery assembly 1 is configured so that each unit cell 11 is stacked in the vertical direction in a horizontal posture. The battery pack 100 in which the battery blocks 10 are connected in parallel can increase the output current, and the battery pack 100 in which the battery blocks 10 are connected in series can increase the output voltage. In the example of FIG. 17, the unit cells 11 are stacked in two upper and lower stages, each cell block 10 connects six unit cells 11 in parallel, and 14 sets of cell blocks 10 are connected in series to output terminal 33. Connected to. The output terminal 33 is a connector and functions as a communication and charging terminal. Further, as shown in FIGS. 6, 15, and 17, the first end face cover 31 is provided with a positive discharge output terminal 33 + and a negative discharge output terminal 33-and is open to the end face plate 31 </ b> H. It is exposed to the outside through the opening window.
(Battery block 10)

As shown in FIG. 18, each battery block 10 holds six unit cells 11, which are cylindrical secondary batteries, with a battery spacer 12. The battery spacer 12 is made of a member having excellent insulating properties, and is made of a resin such as plastic. In particular, a material that is elastically deformed somewhat is preferable. The battery spacer 12 is formed vertically and horizontally symmetrical.
(Battery spacer 12)

  In the example of the battery spacer 12 shown in FIG. 18, three battery cells 11 are stacked in two upper and lower stages and have six battery holding surfaces 13 for holding them in a parallel posture. Each battery holding surface 13 has a substantially semicircular shape whose cross section is curved along the cylindrical surface of the unit cell 11, with the upper three open upward and the lower three open downward. . To be precise, as shown in the cross-sectional view of FIG. 21, a protrusion is provided in the opening so that the cross section of the battery holding surface 13 is larger than half of the cross sectional area of the unit cell 11, and the width of the opening is the unit cell 11. It is configured to be slightly smaller than the diameter. Thus, after the resin battery spacer 12 is elastically deformed and the unit cell 11 is inserted into the battery holder, the unit cell 11 can be prevented from falling off. The unit cell 11 is fixed to the battery holding surface 13 with a double-sided tape or an adhesive. In this battery block 10, the shape of the battery spacer 12 is minimized. Further, the upper and lower surfaces of the battery assembly 1 are insulated by an insulating cover body 15 that covers the exposed surface of the unit cell 11. As shown in FIGS. 7 to 8, the battery assembly 1 is housed in the outer case 30 with the cover bodies 15 fixed to the upper and lower surfaces, and the end surfaces thereof are the first end surface plate 31H and the second end surface table. It is closed with the face plate 32H.

Thus, by dividing the unit cells 11 into battery block units and connecting them in units of battery blocks, the battery block can be prevented from becoming large and heavy, and the battery block assembly workability can be maintained by keeping the battery blocks small. The advantage that can be improved is obtained.
(Battery block stage 2)

The battery blocks 10 are connected in the lateral direction to constitute the battery block stage 2. Therefore, as shown in FIGS. 11 to 12 and FIGS. 19 to 20, the battery spacer 12 is provided with a spacer connecting portion 16 for connecting another battery spacer 12 to the side surface.
(Spacer connecting part 16)

  As shown in FIG. 20, the spacer coupling portion 16 is inserted into a coupling groove 17 opened between the upper and lower battery holding surfaces 13. The spacer connecting portion 16 has left and right connecting protrusions that are formed in an arrowhead shape so that the battery spacer 12 can be connected to the left and right. In addition, the connecting groove 17 has a cross section that is open in a shape corresponding to the arrowhead shape so that the connecting protrusion can be inserted into the connecting groove 17. The spacer connecting portion 16 is made of a resin having elasticity similar to the battery spacer 12 and can be connected by being slidably inserted from the end opening of the connecting groove 17. Using this spacer connecting portion 16, adjacent battery spacers 12 can be mechanically connected as shown in FIGS. Although the spacer connecting portion 16 is a separate member in this example, it goes without saying that it can be provided integrally with the battery spacer. For example, battery spacers can be connected to each other by opening a connection groove on one side surface of the battery spacer and projecting a connection protrusion on the other side surface. However, in this case, since the battery spacer is asymmetrical, the manufacturing efficiency is slightly reduced, and the connecting protrusion protrudes from one end face of the battery block stage 2, so that the width is increased accordingly. Therefore, it can be said that it is preferable to use the spacer connecting portion of the separate member described above.

The spacer connecting portion 16 is a side surface of the battery spacer 12 and is disposed between the upper and lower battery holding surfaces 13. Thereby, the spacer connecting part 16 is disposed in the dead space between the battery holding surfaces 13 to effectively use the space, and the battery spacers 12 are connected to each other by connecting the battery spacers 12 via the spacer connecting part 16. Can be easily configured.
(Unit cell 11)

In this way, the battery block stage 2 as shown in FIG. 19 is configured, and the unit cell 11 is held on the battery mounting surface. In the illustrated battery block 10, the unit cell 11 is a unit cell of a lithium ion battery. A battery pack using a lithium ion battery can increase output with respect to volume and weight. However, instead of the lithium ion battery, a lithium polymer battery or a nickel metal hydride battery can be used as the unit cell. Therefore, the present invention does not specify a unit cell as a lithium ion battery, and any unit cell that can be charged can be used as the unit cell. Further, the unit cell 11 is provided with a temperature sensor for temperature detection. In addition to providing a temperature sensor for each unit cell, only the unit cell at a representative position may be monitored.
(Lead plate 20)

  In the battery block 10, the lead plates 20 are fixed to the end electrodes on both ends of the unit cell 11 held by the battery spacer 12 by spot welding or the like, and the unit cells 11 are connected in parallel and in series. Specifically, as shown in FIG. 17, for each battery block 10, the lead plate 20 connects the end faces of the unit cells 11 to connect the unit cells 11 in parallel, and connects the adjacent battery blocks 10 to each other. Connect in series. Thus, in the battery block stage 2 in which the battery blocks 10 are arranged in the horizontal direction, as shown in FIG. 10, the end faces of the unit cells 11 are arranged in substantially the same plane, and the end electrodes face the same plane. Spot welding for fixing the lead plate 20 from both end faces of the step 2 can be performed, which is preferable in terms of work efficiency. The battery block 10 adjusts the shape of the lead plate 20 and the direction of the unit cells 11 held by the battery spacer 12 to optimize the number of unit cells 11 connected in parallel and in series. The output voltage can be adjusted by the number of units 11 connected in series, and the output current can be adjusted by the number of units connected in parallel. Further, as shown in FIGS. 9 to 12, the lead plate 20 is provided with a connection terminal 21 for detecting an intermediate potential. In a circuit board 40 to be described later, the voltage and current from the connection terminal 21 are input via lead wires. Further, the lead plate 20 is provided with a lead plate through hole 24 for inserting a through screw 50.

  The lead plate 20 is formed of a thin metal plate having excellent conductivity. In the example of FIG. 10, the first lead plate 20 </ b> A for connecting six unit cells 11 included in one battery block 10 in parallel and the six unit cells 11 also included in one cell block 10 are connected in parallel. And in order to connect in series with the 6 unit cells 11 of the adjacent battery block 10, the 2nd lead board 20B which connects the edge part electrode of the 12 unit cells 11 is used. Further, the first lead plate 20 </ b> A is extended in an L shape so as to extend along the side surface of the battery block stage 2 with the end portion extended to form a lead connection terminal 22. The lead connection terminal 22 has a connection terminal screw hole 23 for connection to a lead connection portion 25 described later.

  As shown in FIG. 16, one end of the lead wire 20L is fixed to the negative side lead plate 20E- of FIG. 9, and the negative output of the battery assembly 1 is further reduced by the metal first through screw 50A-. Screwed to one end. The other end of the lead wire 20L is electrically connected to a circuit board 40 described later for charging. Further, as shown in FIG. 15, the other end of the first through screw 50A- appears on the surface side of the first end face cover 31 and is screwed to the metal terminal plate 33-P in the discharge output terminal 33-. . In this way, a part of the through screw can also be used as a conductive lead. In particular, as the through screw used as the conductive lead, a material obtained by plating a copper material with nickel can be preferably used in consideration of electrical conductivity. Further, other through screws not used as conductive leads can use materials such as iron and stainless steel. Thus, the minus side output of the battery assembly 1 is output from the minus side convex portion 33-T connected to the metal terminal plate 33-P. In addition, the metal terminal plate 33-P includes an integrally provided shunt resistor portion 33-S, and the voltage drop at this portion is connected to the circuit board 40 via a lead wire or the like, so that the voltage drop The current value corresponding to is measured.

On the other hand, the plus side output of the battery assembly 1 is outputted from the plus side lead plate 20E + as disclosed in FIG. Furthermore, it is electrically connected to a circuit board 40 described later via a lead wire for charging. Further, the output from the plus-side lead plate 20E + appears on the surface side of the first end surface cover 31 as disclosed in FIG. 15, and is screwed to the metal terminal plate 33 + P in the discharge output terminal 33+. Furthermore, it outputs from the positive side convex part 33 + T connected to metal terminal board 33 + P.
(Lead connection part 25)

  The battery block stages 2 thus obtained are further connected in the length direction of the unit cell 11 to constitute the battery assembly 1. For this reason, the lead plates 20 are connected to each other by the lead connecting portion 25. As shown in FIGS. 11 to 13, the lead connecting portion 25 is a flat plate made of metal like glasses, and couples a pair of fixed pieces 26. Each fixing piece 26 is provided with a screw hole 27. Each fixing piece 26 is formed to be approximately the same size as the lead connection terminal 22. Further, the metal plate constituting the lead connection portion 25 is thicker than the lead plate 20 and increases the mechanical strength.

  On the other hand, the lead plate 20 to be connected as described above is provided with lead connection terminals 22 each having a connection terminal screw hole 23 opened. A screw receiving portion is opened on the side surface of the battery spacer 12. With this configuration, the lead connection portion 25 can be screwed to the lead connection terminal 22 with the lead connection screw 28. At the same time, it can be fixed to the battery spacer 12 with the lead connection screw 28. As a result, the lead plates 20 are electrically connected to each other, and the battery spacers 12 are mechanically connected to each other by the lead connecting portion 25 of a metal plate thicker than the lead plate 20, thereby increasing the physical connection strength. it can. As shown in FIGS. 9 and 17, the lead connection portions 25 alternately connect the upper and lower battery block stages 2 on both side surfaces of the battery assembly 1. As a result, the battery blocks 10 can be connected in series in a zigzag manner, and the number of serial connections can be increased in a limited space to increase the output.

  Moreover, the advantage that a battery block can be reduced in size is also obtained by preparing the lead connection part 25 which connects the lead plates 20 in series with another member. That is, if the unit cells are connected in series, the result is that the unit cell is connected longer in the cylindrical direction of the unit cell. However, with this configuration, the higher the output, the longer the battery block, and the handling during assembly work. Is troublesome. Therefore, by connecting the battery blocks assembled in parallel to each other in series, the battery blocks can be kept small by avoiding such an increase in length, and workability at the time of assembling the battery pack is improved.

  Further, the screw receiving portion provided in the battery spacer 12 preferably serves also as the connection groove 17. Thus, the connecting grooves 17 having the same shape are formed symmetrically on both side surfaces of the battery spacer 12, and on the other hand, when connected to the other battery spacers 12, the side surfaces of the battery block stage 2 are screw receiving portions. And the structure of the battery spacer 12 can be simplified.

In the above example, the screw connection using the lead connection screw is used for the connection of the lead connection part. However, it is needless to say that other connection methods such as laser welding and adhesion can be used as appropriate. However, the screwing capable of torque management is excellent in terms of reliability.
(Modification)

In addition, the above lead connection part is an example, Comprising: It can also be set as the structure which is not set as a separate member from a lead board. A battery assembly 1 ′ according to such a modification is shown in FIG. The lead plate 20 ′ shown in this figure is a bent part in which a part of the lead plate is extended not to the side of the battery block step but to the upper side as a lead connection terminal and the tip is bent into an L shape. It is a piece 29. And in the battery block stages 2 to be connected facing each other, the bending direction is set to a direction protruding to the other side, and the height of the bent pieces 29 is adjusted to a height that can be overlapped with each other. These bent pieces 29 can be overlapped and connected. With this configuration, it is not necessary to use a separate metal plate for the lead connection portion, so the configuration can be simplified. Here, in addition to the screwing, a method such as welding or adhesion can be used as appropriate for the connection.
(Insulation sheet 35)

When the battery block stages 2 are connected as described above, as shown in FIG. 13 and the like, the insulating sheet 35 is interposed so that the lead plate 20 does not short-circuit at the interface between the battery block stages 2 facing each other. As the insulating sheet 35, paper or plastic film having excellent insulating properties can be used. The insulating sheet 35 has a sheet through hole 36 for inserting the through screw 50. Thereby, positioning and holding | maintenance of the insulating sheet 35 are realizable by opening the connection terminal through-hole 24 opened by the sheet | seat through-hole 36 and the lead board 29, and letting the penetration screw 50 pass.
(Circuit board 40)

  The battery assembly 1 configured as described above appears almost diagonally as shown in FIG. Therefore, the positive and negative outputs are connected to the circuit board 40 via the lead plate 20 and the lead wires, and are connected to the output terminal 33 via the protection circuit mounted on the circuit board 40. The circuit board 40 is a board for mounting a circuit necessary for driving the power supply device, such as a charge / discharge circuit and a protection circuit for controlling the charge / discharge current of each battery block 10, and its components, elements, etc., such as a glass epoxy board Is available. In FIG. 17, the circuit board 40 is disposed on the side surface side of the battery assembly 1 so as to face the side surface on the long side of the exterior case 30 in a state inserted into the storage frame 40 </ b> W (see FIG. 7 and the like). Yes. The circuit board 40 connects the output of the battery assembly 1 to the output terminal 33. Further, the output of a temperature sensor or the like that detects the intermediate potential or the temperature of the unit cell is also appropriately connected via a lead wire or the like.

  On the other hand, various battery information (for example, battery voltage, current, temperature, abnormal condition) is communicated to an external electronic device via the output terminal 33 by the function of the microcomputer mounted on the circuit board 40. At the time of charging, charging is performed through the charging FET element mounted on the circuit board 40 via the output terminal 33. When an abnormality occurs, the charging FET element is turned off to interrupt charging. As disclosed in the above-described structure, at the time of discharging, the discharge is performed from the positive discharge output terminal 33+ and the negative discharge output terminal 33- without passing through the circuit board 40. Note that a fuse or the like can be added so that the battery can be discharged through the fuse or the like during charging and discharging.

  By disposing the circuit board 40 on the side surface side of the exterior case 30 in this way, it is possible to radiate the heat generated from the heat-generating electronic components mounted on the circuit board 40 to the outside through the exterior case 30. . Thus, the layout of the exterior case 30 considering the heat generation of the unit cells and the electronic components can ensure sufficient heat dissipation without adding a cooling mechanism such as air cooling or water cooling by forced air blowing, Peltier element, A battery pack that avoids an increase in size and cost due to the heat dissipating member can be realized. Especially for battery packs that require waterproofness, it is difficult to provide a forced cooling mechanism that cools the cooling fan by forcibly sending cooling air, and a battery pack that can exhibit sufficient cooling capacity even without a fan is useful It becomes.

  The battery pack according to the present invention can be suitably used as a power supply device for an assist bicycle.

DESCRIPTION OF SYMBOLS 100 ... Battery pack 1, 1 '... Battery assembly 2 ... Battery block stage 2A ... First battery block stage 2B ... Second battery block stage 3 ... Battery block row 10 ... Battery block 11 ... Unit cell 12 ... Battery spacer 13 ... Battery holding surface 14 ... Spacer through hole 15 ... Cover body 16 ... Spacer connecting portion 17 ... Connecting groove 20, 20 '... Lead plate 20A ... First lead plate 20B ... Second lead plate 20E -... Negative side lead plate 20E + ... Plus Side lead plate 20L ... lead wire 21 ... connecting terminal 22 ... lead connecting terminal 23 ... connecting terminal screw hole 24 ... connecting terminal through hole 25 ... lead connecting portion 26 ... fixing piece 27 ... screw hole 28 ... lead connecting screw 29 ... folding Curved piece 30 ... exterior case 30F ... irregularities 31 ... first end face cover 31H ... first end face surface plate 32 ... second end face cover 32H ... second end face surface plate 33 ... output terminal 33+ ... Polar discharge output terminal 33 -... Negative discharge output terminal 33-P ... Metal terminal plate 33-T ... Minus side convex portion 33-S ... Shunt resistor portion 33 + P ... Metal terminal plate 33 + T ... Positive side convex portion 35 ... Insulating sheet 36 ... Sheet through hole 40 ... Circuit board 40W ... Storage frame 50 ... Through screw 50A, 50A -... First through screw 50B ... Second through screw BS ... Empty space

Claims (14)

A plurality of unit cells (11) having a cylindrical outer can;
A battery spacer (12) for holding the plurality of unit cells (11) in a posture parallel to each other;
A plurality of battery blocks (10) comprising:
For each battery block (10), the end faces of the unit cells (11) held by the battery spacer (12) are connected to connect the unit cells (11) in parallel, and adjacent battery blocks (10) A lead plate (20) for connecting them in series;
A circuit board (40) electrically connected to the lead plate (20);
An exterior case (30) housing the battery block (10) and the circuit board (40) inside;
A battery pack comprising:
The battery blocks (10) are battery block stages (2) arranged parallel to each other so that the end faces of the unit cells (11) included in the battery block (10) are substantially in the same plane,
A plurality of the battery block stages (2), and a battery assembly (1) laminated so as to be arranged in a substantially straight line in the cylindrical length direction so that the end faces of the unit cells (11) face each other. Made up of,
For each battery block stage (2) that is stacked and adjacent, the lead plate (20) is extended to the side surface of the battery assembly (1), and the extended portions of the lead plate (20) are electrically connected to each other. It has a lead connection part (25) for connection,
The lead connection part (25) is formed by alternately changing the side surfaces of the battery assembly (1) between adjacent battery block stages (2) to connect the lead plates (20). Battery pack featuring. The battery pack according to claim 1,
The lead connecting portion (25) is a metal flat plate connecting a pair of fixing pieces (26) having screw holes, and the thickness of the flat plate is configured to be thicker than the lead plate (20). And
The lead plate (20) includes a lead connection terminal (22) bent in an L shape along the side surface of the battery block stage (2), and the lead connection terminal is a connection terminal screw. Open the hole (23),
The battery spacer (12) has a screw receiving portion opened on a side surface of the battery assembly (1),
The battery pack, wherein the lead connection part (25) is fixed to the lead connection terminal (22) and the battery spacer (12) by screwing a lead connection screw (28). The battery pack according to claim 1,
The lead connection part (25) is a bent piece that is a part of the lead plate (20) protruding from the upper surface of the battery assembly (1) and bent into an L shape,
A battery pack characterized in that adjacent lead plates (20) are connected to each other by overlapping and bending the bent pieces. The battery pack according to any one of claims 1 to 3,
The battery spacer (12) holds the plurality of unit cells (11) in two stages, holds them in parallel with each other, and holds the cells bent along the cylindrical surface of the unit cells (11). A battery pack having a surface (13) opened vertically. The battery pack according to claim 4, further comprising:
In the length direction of the outer case (30), the metal assembly (1) that penetrates in parallel, provided with a plurality of through screws (50),
The battery spacer (12) is made of insulating resin,
The battery spacer (12) is formed by aligning the center axis of the battery holding surface (13) that opens vertically with a substantially straight line,
A battery pack, wherein a spacer through hole (14) for inserting the through screw (50) is opened in at least one of the adjacent battery holding surfaces (13). The battery pack according to claim 5,
The battery pack, wherein the plurality of through screws (50) are arranged so as to penetrate each battery block (10) constituting the battery block stage (2). The battery pack according to claim 6, further comprising:
Disposed between the battery block steps (2), an insulating insulating sheet (35) for insulating by interposing between the opposing lead plates (20),
A battery pack, wherein a sheet through hole (36) for inserting the through screw (50) is opened in the insulating sheet. The battery pack according to claim 7,
The battery spacer (12) includes a spacer connecting portion (16) for connecting to another battery spacer (12) constituting the battery block stage (2),
The battery pack, wherein the spacer connecting portion (16) is disposed between the upper and lower battery holding surfaces (13) on a side surface of the battery spacer (12). The battery pack according to claim 8, wherein
The battery spacer (12) is a side surface of the battery assembly (1), and upper and lower battery holding surfaces (13).
A connecting groove (17) is opened between the battery spacers, and by inserting a spacer connecting portion (16) into the connecting groove (17), adjacent battery spacers (12) can be mechanically connected to each other. The battery pack characterized by becoming. The battery pack according to claim 9,
The battery pack, wherein the connecting groove (17) is also used as a screw receiving portion. The battery pack according to any one of claims 5 to 10,
A battery pack, wherein part of the plurality of through screws (50) is also used as a conductive lead. The battery pack according to any one of claims 1 to 11,
The battery assembly (1), the battery block stage (2) located on the end face, the other battery block stage (2)
A battery pack comprising a smaller number of battery blocks (10) to form an empty space (BS) and an output terminal (33) arranged in the empty space (BS). The battery pack according to claim 12, wherein
The battery block (10) uses three unit cells (11),
The battery assembly (1) has four first battery block stages (2A) formed by connecting three battery blocks (10), and two battery blocks (10) on its end face. A battery pack comprising a second battery block stage (2B) connected and connected in one stage. The battery pack according to any one of claims 1 to 13,
An output voltage of the battery pack is 48V.

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