Battery pack

Abstract

The invention makes it easy to fill the interior of an exterior case with a potting material. A battery pack 100 is provided with: a spacer section 25 that is inserted between mutually facing block end surfaces 2b of a plurality of battery blocks 2; an exterior case 10 that houses the plurality of battery blocks 2 and the spacer section 25 in an interior space; and a filling material 50 which is filled into gaps between the inner surface of the exterior case 10 and the surfaces of the plurality of battery blocks in the interior space. The exterior case 10 is open at: a filling hole 14 for filling the filling material 50 in an uncured state into gaps between the inner surface of the exterior case 10 and the surfaces of the plurality of battery blocks 2 in the interior space; and an air hole 15 that is opened so as to be spaced apart from the filling hole 14. The filling hole opens at a position in the inner surface of the exterior case 10 that communicates with a gap between the block end surfaces 2b. The spacer section 25 communicates with the filling hole 14 and forms part of a guide path for guiding the filling material 50 into the interior space.

Description

Battery pack

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

[0002] Battery packs that house battery blocks composed of rechargeable secondary battery cells such as lithium-ion secondary batteries inside an exterior case to power electrical devices are used for various purposes. In some battery packs, a potting material is filled inside the exterior case to fill gaps and improve heat dissipation (see, for example, Patent Document 1). In such a battery pack, it is necessary to ensure a flow path for filling the potting material so that the potting material can smoothly fill the interior of the exterior case.

[0003] However, it is not easy to ensure that the potting material is distributed throughout the gap between the inner surface of the exterior case and the surface of the battery block, and it is particularly difficult to distribute the potting material around the four corners of the exterior case, which can result in the formation of air pockets.

[0004] Japanese Patent Application Laid-Open No. 2012-209135

[0005] One object of the present disclosure is to provide a battery pack that makes it easy to fill the inside of the outer case with a potting material. Another object is to provide a battery pack that is explosion-proof. Note that the description of these objects and objects of the present disclosure does not preclude the existence of other objects and objects. Furthermore, it is not necessary for one embodiment of the present disclosure to solve all of these objects. Furthermore, other objects can be extracted from the description of the specification, drawings, and claims of the present disclosure.

[0006] A battery pack according to one embodiment of the present disclosure includes: a plurality of battery blocks each including one or more secondary battery cells, the plurality of battery blocks having a first block main surface and a block end surface intersecting the first block main surface; a spacer portion inserted between the opposing block end surfaces of the plurality of battery blocks; an exterior case that houses the plurality of battery blocks and the spacer portion in an internal space; and a filler material filled between the inner surface of the exterior case and the surfaces of the plurality of battery blocks in the internal space, wherein the exterior case has a filling hole for filling the filler material in an uncured state between the inner surface of the exterior case and the surfaces of the plurality of battery blocks in the internal space, and an air hole opened at a distance from the filling hole, the filling hole being opened at a position on the inner surface of the exterior case that communicates with the space between the block end surfaces, and the spacer portion is in communication with the filling hole to form part of a guide path for guiding the filler material into the internal space.

[0007] Another embodiment of a manufacturing method for a battery pack includes a plurality of battery blocks each including one or more secondary battery cells, each having a block first main surface and a block end surface intersecting the block first main surface; a spacer portion inserted between the block end surfaces of the plurality of battery blocks; and an exterior case that houses the plurality of battery blocks and the spacer portion in an internal space, the method including the steps of: filling a filler material into the internal space between the inner surface of the exterior case and surfaces of the plurality of battery blocks from a filling hole that is opened in the exterior case and communicates with the block end surfaces on the inner surface of the exterior case, through a part of a guide path that is formed in the spacer portion and communicates with the filling hole to guide the filler material into the internal space; and removing air that is pushed out of the internal space by filling the filler material through an air hole that is opened away from the filling hole; and hardening the filler material.

[0008] According to the battery pack according to one embodiment of the present disclosure, when filling the internal space with the filler material through the filling hole, the filler material can be smoothly guided via the guide path of the spacer portion.

[0009] 1. A perspective view showing a battery pack according to the first embodiment. 1. An exploded perspective view of the battery pack of FIG. 1. 2. An exploded perspective view of the battery pack of FIG. 2, seen from below. 2. A perspective view of the core block of FIG. 2. 3. A perspective view of the core block of FIG. 4, seen from below. 4. An exploded perspective view with the board removed from FIG. 4. 6. An exploded perspective view with the battery holder removed from FIG. 6. 7. A perspective view of the battery block connection body of FIG. 7. 8. A perspective view of the battery block connection body of FIG. 8, seen from below. 9. A perspective view of the battery block connection body of FIG. 8, seen from the rear side. 10. A perspective view of the battery holder, seen diagonally from below. 11. A perspective view of the battery holder, seen diagonally from below on the rear side. 12. A cross-sectional view of the core block of FIG. 4, taken along line XIII-XIII. 13. A cross-sectional view of the core block of FIG. 4, taken along line XIV-XIV. 14. A perspective view of the core block of FIG. 5, with the battery block removed from the core block. 15. A schematic perspective view showing the movement direction of air and filler within the battery pack. 16. A vertical cross-sectional view of the battery pack of FIG. 1, taken along line XVII-XVII. 17. An exploded perspective view with the intermediate lead plate removed from the state of FIG. 8. 18. An exploded perspective view of FIG. 18, seen from the rear side. 19. A perspective view of the intermediate lead plate. Fig. 2 is a horizontal cross-sectional view of the battery pack taken along line XXI-XXI of Fig. 1. Fig. 3 is a perspective view showing a battery holder of a battery pack according to a second embodiment.

[0010] The embodiments of the present disclosure may be specified by the following configurations and features.

[0011] In a battery pack according to another aspect of the present disclosure, in the above aspect, the spacer portion forms a recess that is U-shaped in cross section, forming a part of the guide path in the recess, and the spacer portion has a communication opening at the bottom surface of the recess at a position that overlaps with the filling hole in plan view. With this configuration, even while providing the spacer portion between the battery blocks, by opening the communication opening at a position that overlaps with the filling hole, the spacer portion does not hinder the filling of the filler.

[0012] In a battery pack according to another aspect of the present disclosure, in any of the above aspects, the exterior case is formed in a rectangular shape extending in a first direction, and the filling hole is opened at the middle in a second direction intersecting the first direction. With this configuration, it is possible to evenly fill the internal space with filler material through the filling hole opened at the middle in the width direction.

[0013] In a battery pack according to another aspect of the present disclosure, in any of the above aspects, the filler hole is opened at the middle in the first direction. With this configuration, it is possible to uniformly fill the internal space with filler material through the filler hole opened at the middle in the longitudinal direction.

[0014] In a battery pack according to another aspect of the present disclosure, in any of the above aspects, the battery pack further includes intermediate lead plates that electrically connect the plurality of battery blocks between the block end faces, and the intermediate lead plates include bridge pieces that extend in a direction along the first main surfaces of the blocks and at positions that do not overlap the filler holes between the block end faces. With this configuration, the bridge pieces of the intermediate lead plates that connect the block end faces can be positioned so as not to interfere with the progress of filler material being filled through the filler holes, allowing for smooth filling of the filler material.

[0015] In a battery pack according to another aspect of the present disclosure, in any of the above aspects, the spacer portion has a spacer recess formed in a part of a recess formed in a U-shape in cross section, in which the bridge piece is disposed. With this configuration, the bridge piece of the intermediate lead-plate can be disposed in the guide path of the spacer portion without interfering with the guide path.

[0016] In addition, a battery pack according to another aspect of the present disclosure is any of the above-described aspects, further including a circuit board electrically connected to the plurality of battery blocks, the circuit board having a board cutout formed by partially cutting out a portion that intersects with the guide path. With the above configuration, by partially forming the board cutout in the circuit board that must be positioned in a position that intersects with the guide path, it is possible to prevent the circuit board from interfering with the filling of the filler.

[0017] In addition, in a battery pack according to another aspect of the present disclosure, in any of the above aspects, the spacer portion has a side wall that closes at least one side of a recess that is U-shaped in cross section, and a spacer cutout that partially exposes the recess is formed in a part of the side wall, and the substrate cutout and the spacer cutout are aligned. With the above configuration, by providing a side wall on the spacer portion and forming the spacer cutout in the side wall that intersects with the guide path, it is possible to prevent the side wall from interfering with the filling of the filler.

[0018] In addition, in a battery pack according to another aspect of the present disclosure, in any of the above aspects, the spacer cutout is formed to be the same size as or smaller than the substrate cutout, and with this configuration, it is possible to control the flow of filler during filling by changing the size of the spacer cutout.

[0019] In a battery pack according to still another aspect of the present disclosure, in any of the above aspects, the spacer portion has a second spacer cutout formed on the side opposite to the side on which the spacer cutout is formed. With this configuration, by providing the spacer cutout on one side of the spacer portion and the second spacer cutout on the other side, it is possible to design the spacer portion so that the size of the second spacer cutout can be adjusted according to the amount of filler to be filled on the left and right sides, and it is possible to design the spacer portion so that the filler is balanced according to the conditions of the internal space of the actual battery pack.

[0020] In a battery pack according to still another aspect of the present disclosure, in any of the above aspects, the spacer portion has a groove formed on its surface at a distance from the air hole. This configuration is expected to have the effect of guiding the flow of filler material toward the air hole so as to be guided toward the groove, thereby preventing the filler material from becoming uneven in the internal space.

[0021] In a battery pack according to still another aspect of the present disclosure, in any of the above aspects, the groove is formed so as to be continuous with the side surface of the filler hole, and this configuration is expected to have the effect of suppressing the flow of filler material that tends to flow from the vicinity of the filler hole toward the air hole by guiding it to the groove.

[0022] In a battery pack according to another aspect of the present disclosure, in any of the above aspects, the spacer portion is part of a battery holder that holds the plurality of battery blocks. This configuration provides the advantage of simplifying the configuration without increasing the number of parts by forming a spacer portion that defines a guide path in part of the battery holder.

[0023] In addition, in the battery pack according to any one of the above aspects, the filler is a silicone resin or a urethane resin.

[0024] Embodiments of the present disclosure will be described below with reference to the drawings. However, the embodiments described below are merely examples for embodying the technical concepts of the present disclosure, and the present disclosure is not limited to the following. Furthermore, this specification does not in any way specify the components set forth in the claims to be those of the embodiments. The dimensions, materials, shapes, relative positions, etc. of components described in the embodiments are not intended to limit the scope of the present disclosure, and are merely illustrative examples, unless otherwise specified. The size and positional relationships of components shown in the drawings may be exaggerated for clarity. Furthermore, in the following description, the same names and symbols indicate components that are identical or of the same quality, and detailed descriptions will be omitted as appropriate. Furthermore, the elements constituting the present disclosure may be configured with the same components, such that multiple elements are served by a single component, or conversely, the functions of a single component may be shared by multiple components.

[0025] The battery pack of the present disclosure can be used as a power source for portable electrical devices such as radios, electric cleaners, and power tools, as a driving power source for mobile objects such as electric carts, electric scooters, and assisted bicycles, as a backup power source for servers in stationary power storage applications, as a power supply device for home, office, or factory use, and as a driving power source for vehicles such as hybrid cars and electric cars. Hereinafter, a battery pack used as a power source for a transceiver will be described as one embodiment of the present invention. [Embodiment 1]

[0026] A battery pack 100 according to a first embodiment of the present disclosure is shown in Figures 1 to 21. In these figures, Figure 1 is a perspective view showing the battery pack 100 according to the first embodiment, Figure 2 is an exploded perspective view of the battery pack 100 of Figure 1, Figure 3 is an exploded perspective view of the battery pack 100 of Figure 2 as seen from below, Figure 4 is a perspective view of the core block 4 of Figure 2, Figure 5 is a perspective view of the core block 4 of Figure 4 as seen from below, Figure 6 is an exploded perspective view of Figure 4 with the board removed, Figure 7 is an exploded perspective view of Figure 6 with the battery holder 20 removed, Figure 8 is a perspective view of the battery block connection body 3 of Figure 7, Figure 9 is an exploded perspective view of the battery block connection body 3 of Figure 8 as seen from below, Figure 10 is a perspective view of the battery block connection body 3 of Figure 8 as seen from the rear side, Figure 11 is a perspective view of the battery holder 20 as seen from diagonally below, and Figure 12 is a perspective view of the battery holder 20 of Figure 11 as seen from the rear side. Fig. 13 is a perspective view from diagonally below, Fig. 13 is a cross-sectional view of the core block 4 of Fig. 4 taken along line XIII-XIII, Fig. 14 is a cross-sectional view of the core block 4 of Fig. 4 taken along line XIV-XIV, Fig. 15 is a perspective view of the core block 4 of Fig. 5 with the battery block 2 removed, Fig. 16 is a schematic perspective view showing the direction of movement of air and filler 50 within the battery pack 100, Fig. 17 is a vertical cross-sectional view of the battery pack 100 of Fig. 1 taken along line XVII-XVII, Fig. 18 is an exploded perspective view of the battery pack 100 of Fig. 8 with the intermediate lead plate 40 removed, Fig. 19 is an exploded perspective view of Fig. 18 taken from the rear, Fig. 20 is a perspective view showing the intermediate lead plate 40, and Fig. 21 is a horizontal cross-sectional view of the battery pack 100 of Fig. 1 taken along line XXI-XXI. The battery pack 100 shown in these figures includes an outer case 10 and a core block 4. (Outer case 10)

[0027] The outer case 10 houses the core block 4. The outer shape of the outer case 10 can be any shape that has an internal space inside. In the example shown in Figures 1 to 3, the outer case 10 is formed into a box shape with an exterior that extends in a first direction. The box-shaped outer case 10 is divided into an upper case 11 and a lower case 12, which are divided vertically or horizontally. This outer case 10 is preferably made of a material with excellent insulating properties, such as a resin such as polycarbonate or PC-ABS alloy. It may also be made of a metal material such as aluminum or its alloy. An internal space is defined inside the box shape to house the core block 4. (Core Block 4)

[0028] 2 and 3, the core block 4 is housed in the internal space of the exterior case 10. In this state, a filler 50 (see FIG. 17) is filled into the gap between the inner surface of the exterior case 10 and the surface of the core block 4 in the internal space.

[0029] The core block 4 is formed by integrating multiple components as shown in Figures 4 to 7. Specifically, the core block 4 is made up of a battery holder 20, a circuit board 30, and a battery block connector 3. (Battery block connector 3)

[0030] A battery block connection body 3 is formed by connecting multiple battery blocks 2. Examples of the battery block connection body 3 are shown in Figs. 8 to 9. Each battery block 2 is formed by one or more secondary battery cells 1. The battery blocks 2 are connected to each other via intermediate lead plates 40. In the examples shown in Figs. 8 to 10, each battery block 2 is formed by one secondary battery cell 1. However, each battery block may be formed by two or more secondary battery cells. In the examples shown in Figs. 8 to 10, prismatic secondary battery cells with rectangular outer cans are used as the secondary battery cells 1, but this is not limiting, and pouch-shaped secondary battery cells or cylindrical secondary battery cells may also be used. (Battery Block 2)

[0031] Each battery block 2 has a first block principal surface 2a and a block end surface 2b intersecting the first block principal surface 2a. In the examples shown in Figures 8 to 10, each battery block 2 is composed of a single rectangular secondary battery cell 1, and therefore the block end surface 2b is the cell end surface of the secondary battery cell 1. Furthermore, multiple battery blocks 2 are connected such that the block end surfaces 2b of the battery blocks 2 face each other. In the examples shown in Figures 8 to 10, multiple battery blocks 2 are aligned in a line along the longitudinal direction of the battery block 2 and connected by intermediate lead plates 40. The multiple secondary battery cells 1 are connected in series or in parallel via the intermediate lead plates 40 or the like. The number of series connections or parallel connections can be set as desired depending on the required specifications. In the examples shown in Figures 8 to 10, two secondary battery cells 1 are connected in series, but this configuration is not limited to this. Furthermore, a core block may be composed of multiple battery blocks, and each battery block may contain multiple secondary battery cells. (Secondary Battery Cell 1)

[0032] Each secondary battery cell 1 can be a secondary battery cell with a cylindrical or prismatic outer shape. In the examples shown in Figures 8 to 10, etc., prismatic secondary battery cells 1 are used arranged horizontally. The number and arrangement of secondary battery cells 1 are not limited to this example, and any number and arrangement can be used as appropriate. For example, cylindrical secondary battery cells can be arranged in a matrix. Each secondary battery cell 1 has positive and negative electrodes. The positive and negative electrodes are preferably provided on one cell end face of the secondary battery cell 1. Known secondary batteries, such as lithium-ion secondary batteries, nickel-metal hydride batteries, and nickel-cadmium batteries, can be used as appropriate for the secondary battery cells 1. (Battery holder 20)

[0033] The battery holder 20 is a component for holding multiple battery blocks 2. The battery holder 20 may also include a mechanism for holding or positioning the intermediate lead plate 40. Furthermore, a spacer portion 25 is formed on a portion of the battery holder 20. The spacer portion 25 is inserted between the opposing block end surfaces 2b of multiple battery blocks 2. By forming the spacer portion 25 that defines the guide path on a portion of the battery holder 20 in this way, the configuration can be simplified without increasing the number of parts. This battery holder 20 preferably has the spacer portion 25 formed integrally. However, the battery holder may also be divided into multiple sub-holders. The battery holder 20 can also be made of resin such as polycarbonate.

[0034] The battery holder 20 shown in Figures 7 and 11-12 has an open bottom, defining a storage space for storing the battery block 2. To this end, the battery holder 20 includes a plate-shaped top panel 21, side walls 22 extending longitudinally from the top panel 21, a pair of end walls 23 formed on the longitudinal ends, and a partition wall 24 parallel to the end walls 23 that defines the battery block 2. Output terminals and the like are located on the end walls 23. An opening window may be formed on one end of the exterior case 10 to expose the output terminals from the exterior case 10.

[0035] The side walls 22 are approximately the same length as the top plate 21 and are positioned to intersect with the top plate 21 along the side of the top plate 21. The battery holder 20 shown in Figures 11 and 12 has a side wall 22 on only one side, leaving the other side open. The side walls 22 cover the sides of the battery block 2 and also serve as guides for positioning the circuit board 30. (Partition wall 24)

[0036] As shown in Figures 11 to 14, two partition walls 24 are formed parallel to each other in the longitudinal center of the top plate 21. A recess 26 is formed between the two partition walls 24 and a portion of the top plate 21. Of the battery holder 20, the two partition walls 24 and a portion of the top plate 21 essentially form the spacer portion 25. The recess 26 is formed in a slit shape, and both sides are closed. In the example shown in Figures 12 and 15, one side of the recess 26 is closed by a portion of the side wall 22 (the middle portion in the figure). (Filling hole 14)

[0037] On the other hand, as shown in Figures 16 and 17, the exterior case 10 has a fill hole 14 and an air hole 15. The fill hole 14 and the air hole 15 are spaced apart from each other. The fill hole 14 is a hole for filling a filler 50 between the inner surface of the exterior case 10 and the surfaces of the multiple battery blocks 2 in the internal space. (Air hole 15)

[0038] The air hole 15 is a hole for venting air from the internal space when the filler 50 is filled into the internal space through the filling hole 14 .

[0039] The filling hole 14 is opened at a position on the inner surface of the outer case 10 that communicates with the space between the block end faces 2b. In the examples shown in Figures 2 and 7, two battery blocks 2, each composed of rectangular secondary battery cells 1, are housed side by side along the longitudinal direction of the outer case 10. Therefore, the space between the block end faces 2b is located midway along the first longitudinal direction. When filling the filler 50 through the filling hole 14, the filler 50 must travel a long distance in the first longitudinal direction through the internal space of the outer case 10 to reach the end faces. Otherwise, the filler 50 will stop midway, causing a short circuit and creating a void. Therefore, by opening the filling hole 14 approximately in the center of the outer case 10 in the first longitudinal direction, the filler 50 can flow approximately evenly through the internal space from the filling hole 14 to each longitudinal end face, reducing the risk of a short circuit.

[0040] Furthermore, it is preferable that the filling hole 14 be opened midway in a second direction intersecting the first direction. This allows the filler 50 to flow uniformly through the internal space from the filling hole 14, which is opened at approximately the center in the width direction, toward the side, thereby reducing the risk of the filler 50 shorting out (spacer portion 25).

[0041] The spacer portion 25 communicates with the filling hole 14 and forms a guide path for guiding the filler 50 into the internal space. With this configuration, when the filler 50 is filled into the internal space from the filling hole 14, it can be smoothly guided via the guide path of the spacer portion 25.

[0042] Because secondary battery cells and power semiconductors contained in battery packs generate heat, efficient heat dissipation from the inside to the outside is essential to enhance safety and reliability. To improve heat dissipation, a filler material is filled into the gap between the outer case and the core block housed in the internal space to enhance thermal conductivity. However, if the filler material is not fully filled in the gap, forming an air gap, the insulating effect of the air gap can potentially reduce thermal conductivity. However, it is not easy to completely fill the gap between the outer case and the core block. The filler material is filled through a filler hole opened in the outer case, and the longer the distance it travels from the filler hole to the internal space of the outer case, the more likely it is that a short circuit will occur in the filler material. For example, the four corners of the outer case are far from the filler hole, increasing the likelihood of a short circuit. Furthermore, if a plate material such as a circuit board is placed inside the outer case, the plate material may block the progress of the filler material, hindering its filling.

[0043] In contrast, in the battery pack 100 according to this embodiment, spacers 25 are placed between the battery blocks 2, and these spacers 25 define part of the guide path, allowing the filler 50 to be smoothly introduced into the internal space, making it less likely that a short circuit will occur in the charging material (recess 26).

[0044] The spacer portion 25 of the battery holder 20 forms a recess 26 that is U-shaped in cross section, and this recess 26 forms part of the guide path. The spacer portion 25 also has a communication opening 27 at the bottom of this recess 26 that connects to the filler hole 14. In the examples shown in Figures 12 to 13 and 15, the spacer portion 25 is U-shaped in cross section so that it opens downward. The communication opening 27 is also opened at the bottom of the recess 26, as shown in the cross section of Figure 14. The communication opening 27 is opened at a position that overlaps with the filler hole 14 in plan view. This allows the spacer portion 25 to be provided between the battery blocks 2, but by opening the communication opening 27 at a position that overlaps with the filler hole 14, the spacer portion 25 does not interfere with the filling of the filler 50.

[0045] The partition wall 24 is formed with a curved cross section 27b so as to extend continuously from the inner surface of the communication opening 27 across the recess 26. This allows the filler 50 introduced into the recess 26 from the filling hole 14 through the communication opening 27 to be smoothly guided to the bottom of the interior space of the outer case 10, as shown in Figure 17 (groove 28).

[0046] Additionally, the spacer portion 25 of the battery holder 20 can have a groove 28 formed on its surface, spaced apart from the air hole 15. In the example shown in Figure 4 and elsewhere, the groove 28 extends to the left and right of the filler hole 14. Forming the groove 28 on the top surface of the battery holder 20 in this manner prevents the filler material 50 from moving toward the air hole 15 via the shortest route. That is, the filler material 50 supplied to the internal space tends to flow along a path with the least resistance. A path with the least resistance generally has a short path length. As a result, as shown by the solid arrows in the cross-sectional view of Figure 17 , the filler material 50 supplied from the filler hole 14 flows laterally through the slit-like recess 26 or passes through the core block 4 and travels from the bottom to the side of the core block 4, with a portion wrapping around to the top surface of the core block 4. This filler material 50 then moves toward the air hole 15 via the shortest route, as shown by the dashed line. This makes it difficult to fill every corner of the internal space with the filler material 50. In contrast, in the battery pack 100 according to this embodiment, grooves 28 are formed in the top plate 21 of the battery holder 20, which guides the filler 50 that has reached the top surface of the core block 4 toward the grooves 28, thereby inhibiting the movement of the filler 50 as it attempts to travel the shortest distance toward the air holes 15. By restricting the movement of the filler 50 in this way, it is possible to direct the filler 50 so that it spreads evenly throughout the internal space.

[0047] In the example shown in Figure 4, the groove 28 is formed so as to connect to the side of the fill hole 14. However, the present disclosure is not limited to a configuration in which the groove 28 is formed in a straight line through the fill hole 14, but may be formed, for example, on the side of the fill hole opposite the side closer to the air hole. The groove may also be formed in multiple lines. In this way, the groove may be formed in other patterns that restrict the movement of the filler material that tries to shortcut to the air hole. (Intermediate lead plate 40)

[0048] The battery blocks 2 are connected to each other by intermediate lead plates 40. As shown in Figures 8 to 10, 18 and 19, the intermediate lead plates 40 electrically connect the block end surfaces 2b of adjacent battery blocks 2. An example of an intermediate lead plate 40 is shown in the perspective view of Figure 20. The intermediate lead plate 40 shown in this figure includes a first connection piece 41 for connecting to the block end surface 2b of one battery block 2, a second connection piece 42 for connecting to the block end surface 2b of the other battery block 2, and a bridge piece 43 connecting the first connection piece 41 and the second connection piece 42. The first connection piece 41, bridge piece 43, and second connection piece 42 are integrally formed by bending a metal plate or the like. Such intermediate lead plates 40 can be made of highly conductive materials such as aluminum or nickel. (Bridge Piece 43)

[0049] The bridge piece 43 connects the upper ends of the first connecting piece 41 and the second connecting piece 42, making them parallel to each other. Therefore, the bridge piece 43 extends generally in a direction along the block first main surface 2a. Furthermore, when the battery blocks 2 are connected together by the intermediate lead-plates 40, the bridge piece 43 is positioned between the block end faces 2b so as not to overlap with the filling hole 14. In this way, the bridge piece 43 of the intermediate lead-plate 40, which is positioned across the gap between the block end faces 2b, is offset from the filling hole 14 and positioned to avoid crossing the longitudinal direction of the recess 26. This positions the bridge piece 43 of the intermediate lead-plate 40 connecting the block end faces 2b so as not to interfere with the progress of the filler 50 that is filled through the filling hole 14 and then flows through the guide path defined by the recess 26, enabling smooth filling of the filler 50.

[0050] The intermediate lead-plate 40 shown in Figure 20 has a second connection piece 42 that is larger than the first connection piece 41. The second connection piece 42 is bent at its end and pulled out to the side of the battery block 2 as shown in Figure 8 , and then further bent to form an L-shaped third connection piece 44 that extends across the width of the first main surface 2a of the block, the tip of which connects to the circuit board 30 as shown in Figure 6 . As shown in Figure 7 , the third connection piece 44 extends upward in the figure, connecting the first connection piece 41 and the second connection piece 42 of the intermediate lead-plate 40 to each battery block 2. With the top surface of the battery block connection body 3 covered by the battery holder 20, the third connection piece 44 is bent onto the top surface 21 of the battery holder 20 as shown in Figure 4 and other figures to connect to the circuit board 30. (Spacer recess 29)

[0051] 11-12 and 15, the spacer portion 25 of the battery holder 20 has a spacer recess 29 formed in part of the recess 26 for locating the bridge piece 43 of the intermediate lead-plate 40. This allows the bridge piece 43 of the intermediate lead-plate 40 to be positioned along the guide path of the spacer portion 25 without interfering with the placement. [Battery Pack Manufacturing Method]

[0052] An example of a manufacturing method for the battery pack 100 will now be described. First, uncured filler material 50 is filled into the internal space of the outer case 10 through the filling hole 14 opened in the outer case 10. The uncured filler material 50 is introduced through a guide path formed in the spacer portion 25 and communicating with the filling hole 14 to guide the filler material 50 into the internal space, and fills the gap in the internal space between the inner surface of the outer case 10 and the surface of the core block 4. As the uncured filler material 50 is filled, air in the gap in the internal space between the inner surface of the outer case 10 and the surface of the core block 4 is pushed out through the air hole 15. In other words, filling of the uncured filler material 50 and removal of air through the air hole 15 are performed simultaneously.

[0053] A potting material such as silicone resin or urethane resin that has excellent thermal conductivity and is liquid in an uncured state can be used for filler 50. Uncured filler 50 is filled by inserting, for example, a tube-shaped injection pipe from filling hole 14 into exterior case 10 through communication port 27 and curved surface 27b.

[0054] In this state, the filler material 50 is hardened. As a result, the gap between the inner surface of the outer case 10 and the surface of the core block 4 is filled with the hardened filler material 50, the core block 4 is thermally bonded to the outer case 10, and heat generated by the core block 4 can be dissipated from the outer case 10 via the filler material 50, which has excellent thermal conductivity. (Circuit board 30)

[0055] The battery pack 100 also includes a circuit board 30 electrically connected to multiple secondary battery cells 1. The battery block connector 3 is connected to the circuit board 30 via an intermediate lead plate 40, a first lead plate 46, and a second lead plate 47. In the example shown in FIGS. 4 to 7, the first lead plate 46 is connected to the negative electrode side of the battery block connector 3, and the second lead plate 47 is connected to the positive electrode side of the battery block connector 3. In FIG. 7, the first lead plate 46 and the second lead plate 47 are welded to the battery block 2 (secondary battery cells 1). At this stage, the tips of the first lead plate 46 and the second lead plate 47 are not bent but are extended. In this state, the battery block connector 3 is covered by the battery holder 20. At this time, the third connection piece 44 is bent toward the top surface 21 of the battery holder 20. As shown in FIG. 6, the circuit board 30 is fixed to the side wall 22 of the battery holder 20. At this time, the tips of the first lead plate 46 and the second lead plate 47 are folded back onto the circuit board 30. The intermediate lead plate 40 also connects the intermediate potential of the battery block connector 3 to the circuit board 30. Note that for the sake of explanation, Figures 8 to 10 show a state in which the first lead plate 46 and the second lead plate 47 are omitted from the battery block connector 3, while the third connection piece 44 remains. The circuit board 30 is equipped with a charge / discharge circuit that charges and discharges the rechargeable battery cells 1, and a protection circuit that monitors the voltage and temperature of the rechargeable battery cells 1 and cuts off the current in the event of an abnormality. The circuit board 30 is made of a glass epoxy board or the like. A board holder for holding such a circuit board 30 may also be provided.

[0056] As shown in Figures 6 and 7, the circuit board 30 is arranged on one side of the battery holder 20 so as to overlap the side wall 22. In this configuration in which the circuit board 30 is arranged on the side of the core block 4, the circuit board 30 may block the flow path of the filler 50, preventing it from filling the entire interior space of the exterior case 10. Therefore, a board cutout 32 is provided in the circuit board 30 to ensure a flow path for the filler 50. (Board cutout 32)

[0057] 5 to 7, 11 and 12, the circuit board 30 has a board cutout 32 formed by partially cutting out the portion that intersects with the guide path. By partially forming the board cutout 32 in the circuit board 30, which must be positioned in a position that intersects with the guide path, it is possible to prevent the circuit board 30 from interfering with the filling of the filler 50. (Spacer cutout 22b)

[0058] The spacer portion 25 of the battery holder 20 also has a spacer cutout 22b formed in a portion of the sidewall 22, partially exposing the recess 26. The cutout in the battery holder 20 is aligned with the board cutout 32 in the circuit board 30, as shown in Figure 21 . When filling the filler 50 through the filling hole 14, the sidewall 22 and the circuit board 30 are positioned so as to intersect with the flow of the filler 50 being extruded toward the circuit board 30 along the slit-shaped recess 26. By passing through the spacer cutout 22b and the board cutout 32, the filler 50 can proceed along the guide path without being obstructed. The spacer cutout 22b is preferably the same size as or smaller than the board cutout 32. This allows the size of the spacer cutout 22b to control the flow of the filler 50 during filling. [Embodiment 2]

[0059] In the above example, as shown in Figure 15 and other figures, the spacer notch 22b is formed on only one side of the slit-shaped recess 26 formed in the spacer portion 25 of the battery holder 20, and no notch is provided on the other side. However, the present disclosure is not limited to this configuration, and a notch may also be formed on the other side. Such an example is shown in Figure 22 as a battery pack according to embodiment 2. In this figure, components similar to those in embodiment 1 described above are designated by the same reference numerals, and detailed descriptions will be omitted where appropriate.

[0060] The battery holder 20B shown in Figure 22 has a second spacer notch 22c formed on the side of the spacer portion 25B opposite the side where the spacer notch 22b is provided. By providing notches on both sides of the recess 26 in this way, the flow of the filler 50 filled in the recess 26 can be adjusted. That is, when the filler 50 is filled through the filling hole 14, the filler 50 is pushed left and right along the slit-shaped recess 26, as shown in Figures 16 and 17 . The circuit board 30 is positioned so that it intersects with the slit-shaped recess 26, acting as a resistance to the filling of the filler 50. Therefore, as a reaction to the resistance to the filler 50's advance toward the side where the circuit board 30 is provided, the filler 50 tends to move relatively toward the side where the circuit board 30 is not provided. This can easily result in uneven distribution of the filler 50 within the interior space of the exterior case 10.

[0061] Therefore, in the battery pack 100 according to the first embodiment described above, the side of the slit-shaped recess 26 on the side where the circuit board 30 is provided is provided with a notch in the battery holder 20 and a board notch 32 in the circuit board 30, thereby reducing resistance. Conversely, the slit-shaped recess 26 on the opposite side is intentionally blocked to increase resistance and balance the flow of filler 50 from the fill hole 14 to the left and right. However, in practice, the spread and distribution of filler varies depending on various conditions within the battery pack, such as the shape of the core block and the internal space, the size of the gaps, and the viscosity of the filler. For example, it is possible that the amount of filler supplied to the side where the circuit board is provided is greater than that to the opposite side. Therefore, by examining the filler filling behavior through simulations and actual testing, a second spacer notch 22c is formed on the opposite side in addition to the spacer notch 22b to optimally adjust the distribution of filler supplied to the left and right from the fill hole. Furthermore, by adjusting the size of the second spacer notch 22c as shown by the dashed line in FIG. 22 , an optimal design tailored to the battery pack can be achieved. In this way, by adding the second spacer notch 22c to the battery holder 20B, it becomes easier to control the amount of filler 50 to be filled, which has the advantage of allowing for more detailed design.

[0062] In the above example, the battery pack is used as a power source for a portable electrical device. However, the present disclosure is not limited to this. The battery pack can also be attached to various types of electrical devices, such as mobile devices, to supply power to the electrical devices. Examples of electrical devices include portable electrical devices and mobile devices such as electric vehicles and electric carts. In such electrical devices, when the remaining capacity of the battery pack becomes low or the battery pack deteriorates over time, the battery pack can be replaced to continue using the electrical device. However, the present disclosure is not limited to replaceable battery packs that mainly house secondary battery cells, but can also be applied to battery packs in which secondary battery cells are housed within the housing of the electrical device. In the present disclosure, a battery pack is defined as a battery pack that houses secondary battery cells in a case, and also includes a battery pack in which the driving secondary battery cells are built into the housing of the electrical device itself. In other words, the present disclosure is not limited to replaceable battery packs, but can also be applied to electrical devices that house secondary battery cells.

[0063] The battery pack according to the present invention can be suitably used as a power source for radios, a power source for portable electrical equipment such as electric cleaners and power tools, a driving power source for mobile objects such as electric scooters, electric carts and assisted bicycles, a backup power source for servers and the like, and a stationary power storage device for home, office and factory use, etc.

[0064] REFERENCE SIGNS LIST 100 battery pack 1 secondary battery cell 2 battery block; 2a first main surface of block; 2b end surface of block 3 battery block connector 4 core block 10 outer case 11 upper case 12 lower case 14 filling hole 15 air hole 20, 20B battery holder 21 top plate 22 side wall; 22b spacer cutout; 22c second spacer cutout 23 end wall 24 partition wall 25 spacer portion 26 recess 27 communication port; 27b curved surface 28 groove 29 spacer recess 30 circuit board 32 board cutout 40 intermediate lead plate 41 first connecting piece 42 second connecting piece 43 bridge piece 44 third connecting piece 46 first lead plate 47 second lead plate 50 filler

Claims

1. A battery pack comprising: a plurality of battery blocks each including one or more secondary battery cells, each having a block first main surface and a block end surface intersecting the block first main surface; a spacer portion inserted between the opposing block end surfaces of the plurality of battery blocks; an exterior case that houses the plurality of battery blocks and the spacer portion in an internal space; and a filler material filled between the inner surface of the exterior case and the surfaces of the plurality of battery blocks in the internal space, wherein the exterior case has: a filling hole for filling the filler material in an uncured state between the inner surface of the exterior case and the surfaces of the plurality of battery blocks in the internal space; and an air hole opened at a distance from the filling hole, the filling hole being opened at a position on the inner surface of the exterior case that communicates with the space between the block end surfaces, and the spacer portion communicating with the filling hole to form part of a guide path for guiding the filler material into the internal space.

2. A battery pack as claimed in claim 1, wherein the spacer portion forms a recess that is U-shaped in cross section, forming part of a guide path in the recess, and the spacer portion has a communication opening at the bottom surface of the recess at a position that overlaps with the filling hole in plan view.

3. A battery pack as claimed in claim 2, wherein the exterior case is formed in a rectangular shape extending in a first direction, and the filling hole is opened in the middle thereof in a second direction intersecting the first direction.

4. A battery pack according to claim 3, wherein the filling hole is opened at the middle in the first direction.

5. A battery pack as claimed in claim 1, further comprising intermediate lead plates that electrically connect the plurality of battery blocks between the block end faces, the intermediate lead plates including bridge pieces that extend in a direction along the first main faces of the blocks, at positions that do not overlap the filling holes, between the block end faces.

6. A battery pack according to claim 5, wherein the spacer portion has a recess formed in a U-shape in cross section, and a spacer recess in which the bridge piece is disposed is formed in part of the recess.

7. A battery pack as claimed in any one of claims 1 to 6, further comprising a circuit board electrically connected to said plurality of battery blocks, said circuit board having a board notch formed by partially cutting out a portion that intersects with said guide path.

8. A battery pack as claimed in claim 7, wherein the spacer portion has a side wall that closes at least one side of a recess formed in a U-shape in cross section, and a spacer cutout that partially exposes the recess is formed in part of the side wall, and the substrate cutout and the spacer cutout are aligned.

9. A battery pack according to claim 8, wherein the spacer cutout is formed to be the same size as or smaller than the substrate cutout.

10. A battery pack according to claim 8, wherein the spacer portion has a second spacer notch formed on the side opposite to the side on which the spacer notch is provided.

11. A battery pack according to claim 7, wherein the spacer portion has a groove formed on its surface, spaced apart from the air hole.

12. A battery pack according to claim 11, wherein the groove is formed so as to be continuous with the side surface of the filling hole.

13. A battery pack according to any one of claims 1 to 6, wherein the spacer portion is part of a battery holder that holds the plurality of battery blocks.

14. A battery pack according to any one of claims 1 to 6, wherein the filler is a silicone resin or a urethane resin.

15. A method for manufacturing a battery pack comprising: a plurality of battery blocks each including one or more secondary battery cells, each having a block first main surface and a block end surface intersecting the block first main surface; spacer sections inserted between the block end surfaces of the plurality of battery blocks; and an exterior case that houses the plurality of battery blocks and spacer sections in an interior space thereof, the method comprising: filling the interior space between the interior surface of the exterior case and the surfaces of the plurality of battery blocks from filling holes that are opened in the exterior case and communicate with the block end surfaces on the interior surface of the exterior case, through part of a guide path that is formed in the spacer section and communicates with the filling holes to guide the filler into the interior space; while removing air that is pushed out of the interior space by the filling of the filler from air holes that are opened apart from the filling holes; and hardening the filler.

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