Power supply device

Abstract

In the present invention, a power supply device comprises a plurality of secondary battery cells that each have a terminal, heat-conductive battery holders that accommodate the plurality of secondary battery cells, a holder case that accommodates the battery holders, and an exterior case that houses the holder case. The invention comprises a waterproof structure for waterproofing at least the areas that include the terminals of the plurality of secondary battery cells accommodated in the battery holders. The areas are within the battery holders and are positioned between the holder case and each of the battery holders. First cooling air paths through which cooling air flows are formed in the holder case between the inner surface of the holder case and the surfaces of the battery holders. An exterior case exhaust port communicating with the first cooling air paths is formed in the exterior case.

Description

power supply

[0001] The present disclosure relates to a power supply device.

[0002] Power supply devices are used for applications in which multiple rechargeable secondary battery cells, such as lithium-ion secondary batteries, are connected in series or parallel and housed in an exterior case to drive electrical equipment such as power tools, or electrically powered mobile objects such as vehicles and construction machinery (see, for example, Patent Document 1). The secondary battery cells used in such power supply devices generate heat during charging and discharging and therefore need to be cooled. For this reason, in order to cool the secondary battery cells by air, cooling air channels are formed between the secondary battery cells, and openings are provided in the exterior case to communicate with the cooling channels.

[0003] On the other hand, power supplies and other devices used outdoors must be waterproof, so the exterior case must have an opening to allow cooling air in from the outside, while also preventing unintended internal short circuits caused by water seeping in from the outside.

[0004] Republished Patent No. WO2017 / 175487

[0005] One object of one embodiment of the present disclosure is to provide a power supply device that can cool a secondary battery cell while waterproofing it. Another object of another embodiment is to provide a novel power supply device. Note that the description of these objects and problems of the present disclosure does not preclude the existence of other objects and problems. Furthermore, it is not necessary for one embodiment of the present disclosure to solve all of these problems. Furthermore, problems other than these can be extracted from the description of the specification, drawings, and claims of the present disclosure.

[0006] A power supply device according to one embodiment of the present disclosure is a power supply device comprising a plurality of secondary battery cells, each having a terminal, a thermally conductive battery holder that houses the plurality of secondary battery cells, a holder case that houses the battery holder, and an outer case that houses the holder case, and is provided with a waterproof structure that waterproofs an area between the holder case and the battery holder that includes at least the terminals of the plurality of secondary battery cells housed in the battery holder, the holder case forms a first cooling air path for flowing cooling air between the inner surface of the holder case and the surface of the battery holder, and the outer case forms an outer case exhaust port that communicates with the first cooling air path.

[0007] According to one embodiment of the power supply device of the present disclosure, the terminal portions of the multiple secondary battery cells held by the battery holder are waterproofed with a holder case, thereby waterproofing the terminal portions, and cooling air is taken in from the outside through the first cooling air path and circulated over the surface of the battery holder, thereby enabling efficient cooling.

[0008] 1 is a perspective view showing a power supply device according to a first embodiment. 1 is a perspective view of the power supply device of FIG. 1, seen from diagonally below on the rear side. 2 is an exploded perspective view of the power supply device of FIG. 1, with the upper case disassembled. 3 is a further exploded perspective view of the power supply device of FIG. 3. 4 is a cross-sectional view taken along line V-V of the power supply device of FIG. 1. 5 is a perspective view showing one battery block of FIG. 4. 6 is an exploded perspective view of the battery block of FIG. 6. 7 is an exploded perspective view showing the battery block of FIG. 7 removed from the holder case. 8 is an exploded perspective view of the battery holder of FIG. 9. 10 is a cross-sectional view of the battery block of FIG. 6, taken along line X-X. 11 is a cross-sectional view of the power supply device of FIG. 6, taken along line XI-XI. 12 is a plan view showing the power supply device of FIG. 3, with the upper case removed. 13 is a cross-sectional view of the power supply device of FIG. 1, taken along line XIII-XIII. 13 is a cross-sectional view of the power supply device of FIG. 1, taken along line XIV-XIV.

[0009] The embodiments of the present disclosure may be specified by the following configurations and features.

[0010] In another aspect of the power supply device of the present disclosure, in the above aspect, the battery holder covers at least the middle portion of each battery cell excluding the terminals, the holder case forms the first cooling air passage between the surface side of the battery holder covering the middle portions of the battery cells and the inner side of the holder case, the holder case has a holder opening that communicates with the first cooling air passage, and the holder opening is connected to the outer case exhaust port. With this configuration, cooling air flows toward the outer surface of the battery holder that covers the middle portions of the secondary battery cells, enabling efficient cooling of the secondary battery cells.

[0011] In another aspect of the power supply device of the present disclosure, in any of the above aspects, the exterior case has an exterior case air inlet that communicates with the first cooling air path and is located at a position different from the exterior case air outlet, and the middle portion of the battery holder is exposed through the exterior case air inlet. With this configuration, fresh cooling air taken into the exterior case through the exterior case air inlet can efficiently cool the middle portions of the secondary battery cells housed in the battery holder.

[0012] In a power supply device according to another aspect of the present disclosure, in any of the above aspects, each of the plurality of secondary battery cells has a cylindrical exterior can, at least one end face of the cylindrical exterior can serves as the terminal, and the holder case is divided so as to cover the longitudinal end faces of each secondary battery cell. With this configuration, a waterproof structure is achieved by covering the end faces of the secondary battery cells with the holder case.

[0013] In a power supply device according to still another aspect of the present disclosure, in any of the above aspects, the battery holder includes a cylindrical storage container that at least partially houses the secondary battery cells, and the holder opening extends in a direction intersecting the longitudinal direction of the plurality of secondary battery cells. With this configuration, by opening the holder opening in the direction in which the secondary battery cells are stacked, multiple cylindrical storage containers that house the secondary battery cells are exposed from the holder case, thereby improving heat dissipation performance.

[0014] In a power supply device according to still another aspect of the present disclosure, in any of the above aspects, the length of the battery holder is shorter than that of the rechargeable battery cells, and the ends of the rechargeable battery cells are exposed from the rechargeable battery holder. With this configuration, even when a conductive battery holder is used to connect the end faces of the rechargeable battery cells with lead plates or the like, the risk of the end faces of the battery holder touching the lead plates or the like, resulting in unintended electrical connection, can be reduced.

[0015] In yet another aspect of the power supply device of the present disclosure, in any of the above aspects, the holder case houses a plurality of the battery holders, the holder case forms a second cooling air path between the plurality of battery holders, and the exterior case exhaust port is connected to the second cooling air path. With this configuration, cooling air can be circulated through the second cooling air path formed between the plurality of battery holders, allowing efficient cooling of the rechargeable battery cells via the thermally conductive battery holders.

[0016] In a power supply device according to still another aspect of the present disclosure, in any of the above aspects, the waterproof structure is a seal member interposed between the periphery of the battery holder and the inner surface of the holder case. With this configuration, by providing a waterproof structure between the battery holder and the holder case, it is possible to directly air-cool the periphery of each secondary battery cell while simplifying the waterproof structure.

[0017] Furthermore, in another form of the power supply device of the present disclosure, in any of the above forms, the holder case is made of resin, and the battery holder is made of a material that has higher thermal conductivity than the resin that makes up the holder case.

[0018] In addition, the power supply device 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 secondary battery cells, the circuit board being waterproofed by the waterproof structure. With the above configuration, it is possible to waterproof the secondary battery cells as well as the circuit board connected to the secondary battery cells.

[0019] 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 shared by one component, or conversely, the functions of one component may be shared by multiple components.

[0020] The power supply device of the present disclosure can be used as a power source for portable electrical devices such as power tools and electric cleaners, 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 automobiles, etc. Below, a power supply device used as a driving power source for power tools will be described as one embodiment of the present invention.

[0021] [Embodiment 1] A power supply device 100 according to embodiment 1 of the present disclosure is shown in Figures 1 to 14. In these figures, Figure 1 is a perspective view showing the power supply device 100 according to embodiment 1, Figure 2 is a perspective view of the power supply device 100 of Figure 1 seen from diagonally below the rear side, Figure 3 is an exploded perspective view of the power supply device 100 of Figure 1 with the upper case 11 disassembled, Figure 4 is a further exploded perspective view of the power supply device 100 of Figure 3, Figure 5 is a cross-sectional view of the power supply device 100 taken along line V-V of Figure 1, Figure 6 is a perspective view of one battery block 30 of Figure 4, Figure 7 is an exploded perspective view of the battery block 30 of Figure 6, and Figure 8 is a perspective view of the battery block 30 of Figure 7. Fig. 11 is a cross-sectional view of the power supply device 100 of Fig. 6 taken along line XI-XI, Fig. 12 is a plan view of the power supply device 100 of Fig. 3 taken along line XIII-XIII, Fig. 13 is a cross-sectional view of the power supply device 100 of Fig. 2 taken along line XIII-XIII, and Fig. 14 is a cross-sectional view of the power supply device 100 of Fig. 1 taken along line XIV-XIV. The power supply device 100 shown in these figures includes an outer case 10, a battery module 2, and a circuit board 3.

[0022] (External Case 10) The external case 10 houses the battery module 2 and the circuit board 3. The external shape of the external case 10 can be any shape that has an internal storage space. In the example shown in FIGS. 1 to 5, the external case 10 has a box-like shape that extends in one direction (horizontally in the figures). As shown in FIG. 3, the box-shaped external case 10 is composed of an upper case 11 and a lower case 12 that are divided into two parts, upper and lower. However, the present disclosure is not limited to this configuration, and the external case may be divided into three or more parts. The external case may also be divided into left and right parts. The divided external cases are waterproofed by a waterproof structure.

[0023] The exterior case 10 is preferably made of a material with excellent insulating properties, such as a resin such as polycarbonate or PC-ABS alloy, but may also be made of a metal material such as aluminum or its alloy. An internal space is provided inside the exterior case 10 to house the battery module 2 and circuit board 3. In the example shown in Figure 4, etc., an internal space is formed in the lower case 12, and the battery module 2 and circuit board 3 are housed therein.

[0024] (Divider Plate 20) A partition plate 20 is disposed on the upper surface of the battery module 2. The partition plate 20 has a partition plate opening 21, and as shown in FIG. 3 , a portion of the battery module 2 is exposed through the partition plate opening 21. A partition plate elastic body 22 is disposed between the partition plate 20 and the battery module 2. This achieves a waterproof structure that waterproofs the battery module 2 except for the portion exposed through the partition plate opening 21. The area between the periphery of the partition plate 20 and the lower case 12 of the exterior case 10 is also waterproofed by a waterproof structure such as packing or a seal. This makes it possible to waterproof the area indicated by the dashed line in FIG. 3 except for the central portion of the secondary battery cell.

[0025] 4, two partition plate openings 21 are formed in the partition plate 20, and a partition plate elastic body 22 is disposed in each partition plate opening 21. The holder openings 34 of each battery block 30 are exposed through the partition plate openings 21, and the partition plate elastic bodies 22 prevent water and other contaminants from entering the lower case 12 through gaps between the periphery of the partition plate openings 21 and the battery blocks 30.

[0026] Furthermore, the outer case 10 has an outer case air intake port 13 and an outer case air exhaust port 14 opened in a part thereof. The outer case air intake port 13 and the outer case air exhaust port 14 are connected to the first cooling air path FP1. In the example shown in Fig. 2, the outer case air intake port 13 is opened on the bottom surface of the outer case 10, and the outer case air exhaust port 14 is opened on the upper side of the back surface of the outer case 10 (details will be described later).

[0027] (Battery Module 2) The battery module 2, also called a core pack, houses multiple secondary battery cells 1. The battery module may also be composed of multiple battery blocks, each housing multiple secondary battery cells 1. In the examples of Figures 4 and 5, the battery module 2 is constructed by stacking two battery blocks 30.

[0028] (Holder Case 31) Each battery block 30 includes a holder case 31, a battery holder 40, rechargeable battery cells 1, and lead plates 5. The holder case 31 has a box-like exterior as shown in FIG. 6. A holder storage space is formed inside the holder case 31, and the battery holder 40 is stored within the holder storage space. The holder case 31 in FIGS. 6 and 7 is divided into two sections, with a front first holder case 31A and a rear second holder case 31B joined together. However, the holder case is not limited to a two-section structure and may be divided into three or more sections. The divided holder cases are waterproofed by a waterproof structure. The holder case 31 is made of a material with excellent insulating properties. Preferably, it is made of a resin such as polycarbonate or PC-ABS alloy.

[0029] (Battery Holder 40) The battery holder 40 stores and holds multiple rechargeable battery cells 1. To this end, the battery holder 40 has multiple storage cylinders 42 that individually store the rechargeable battery cells 1. In the example shown in Figures 7 to 10, the outer shape of each storage cylinder 42 is hexagonal. Therefore, the outer shape of the battery holder 40 is formed in a honeycomb shape. However, the shape of the battery holder is not limited to this configuration; for example, the outer shape of each storage cylinder may be polygonal, such as an octagon, or cylindrical.

[0030] On the other hand, the interior of the cylindrical storage tube 42 is formed to be large enough to accommodate the rechargeable battery cells 1. Preferably, as shown in Figures 9 and 10 , the interior of the cylindrical storage tube 42 is formed to be cylindrical enough to fit the cylindrical outer can of the rechargeable battery cell 1, so that cylindrical rechargeable battery cells 1 can be stored. In addition, it is preferable that there is a small gap between the outer can of the rechargeable battery cell 1 inserted into the cylindrical storage tube 42 and the inner surface of the cylindrical storage tube 42. By bringing the outer can and the cylindrical storage tube 42 into surface contact, the rechargeable battery cells 1 are thermally coupled to the battery holder 40, and heat generated by the rechargeable battery cells 1 is efficiently conducted to the battery holder 40, thereby improving the cooling effect of the rechargeable battery cells 1.

[0031] The battery holder 40 is made of a material with higher thermal conductivity than the resin that makes up the holder case 31. Preferably, the battery holder 40 is made of a metal such as aluminum or copper, or a resin with higher thermal conductivity than the resin that makes up the holder case 31, or a resin containing a metal filler. This makes it easier for the secondary battery cells 1 housed in the battery holder 40 to dissipate heat to the outside through the battery holder 40.

[0032] The length of the cylindrical storage tube 42 of the battery holder 40 is preferably shorter than that of the rechargeable battery cells 1. For example, in the example shown in Fig. 11 , when a rechargeable battery cell 1 is stored in each cylindrical storage tube 42, the end of the rechargeable battery cell 1 protrudes from the cylindrical storage tube 42. This configuration reduces the risk of unintended conduction caused by the end face of the battery holder 40 coming into contact with the lead plate 5 or the like when connecting the end faces of the rechargeable battery cells 1 with each other using a conductive battery holder 40.

[0033] The battery holder 40 may also be divided into multiple pieces. Multiple battery holders 40 can also be stacked and housed in the holder case 31. In the example shown in Figures 8 and 9, seven battery holders 40 are stacked horizontally and housed in the holder case 31. In this case, it is preferable to form the joint surfaces connecting adjacent battery holders 40 into a periodic shape to facilitate stacking. For example, the polygonal side of the storage tube 42 can create irregularities on the side of each battery holder 40, allowing the irregularities to interlock. In the example shown in Figure 10, the side of each battery holder 40 has an isosceles trapezoidal shape with a flat top and a V-shaped valley at the bottom. This allows the protrusions and recesses to interlock. Furthermore, the sides of the battery holders 40, each consisting of a protrusion and a recess, are not tightly fitted together, but instead form a gap, forming a second cooling air passage FP2 through which cooling air flows (details will be described later). Here, the gaps in the second cooling air passage FP2 are not uniform in width between the convex and concave portions, but are zigzag, forming wide spaces with triangular cross-sectional shapes at the bent portions. In particular, the bent portions are where three secondary battery cells 1 gather, making it easy for heat to concentrate. Widening the gaps in these portions enhances the cooling effect. Furthermore, the upper and lower ends of the second cooling air passage FP2 are slightly wider, making it easier to guide and release cooling air into the second cooling air passage FP2. The example in Figure 10 shows an example in which cooling air flows from bottom to top.

[0034] (Case tubular portion 32) The holder case 31 also has case tubular portions 32 formed on its inner surface that cover the ends of the rechargeable battery cells 1 housed in the battery holder 40. In the example shown in Figure 8, cylindrical case tubular portions 32 are formed integrally with the holder case 31 on the inner surface of the holder case 31 at positions corresponding to each end of the rechargeable battery cells 1.

[0035] (Lead Plates 5) The battery block 30 also includes lead plates 5 for electrically connecting the rechargeable battery cells 1 to each other. The lead plates 5 are preferably arranged on the outer surface of the holder case 31. The holder case 31 also has electrode windows on its side that communicate with the case cylindrical portion 32 to connect the lead plates 5 arranged on the outer surface to the terminals of the rechargeable battery cells 1.

[0036] A plurality of lead plates 5 are installed on both end surfaces of the rechargeable battery cells 1 in the holder case 31, connecting the electrodes on the end surfaces of the rechargeable battery cells 1 to each other, thereby connecting the plurality of rechargeable battery cells 1 together. The lead plates 5 are made of highly conductive metal plates such as aluminum, nickel, or copper. The plurality of rechargeable battery cells 1 are connected in series or in parallel via the lead plates 5. The number of series connections and the number of parallel connections can be set as desired according to the required specifications. In the example shown in FIG. 7 , a total of 70 rechargeable battery cells 1 are used in one battery block 30, forming a 7 series × 10 parallel connection. In the example shown in FIG. 4 , two battery blocks 30 are stacked in the longitudinal direction of the rechargeable battery cells 1 and connected in series, resulting in a 14 series × 10 parallel connection of a total of 140 rechargeable battery cells 1. However, the number of rechargeable battery cells and the connection configuration, i.e., the number of series and parallel connections, are not limited to this configuration.

[0037] (Circuit Board 3) The battery block 30 is connected to the circuit board 3 via lead plates 5 and bus bars. The circuit board 3 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 3 is made of a glass epoxy board or the like. A board holder 4 may also be provided as a member to hold the circuit board 3.

[0038] (Secondary Battery Cells 1) As shown in Figures 7 and 8, each battery block 30 houses secondary battery cells 1 in a holder case 31. The secondary battery cells 1 are housed and held in the housing cylinders 42 of the battery holder 40. Each secondary battery cell 1 can be a cylindrical or rectangular secondary battery cell. In the examples shown in Figures 5, 7 to 10, etc., cylindrical secondary battery cells 1 are used in a staggered arrangement in a horizontal position. Note that the number and arrangement of the 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 may be arranged in a matrix. Known secondary batteries, such as lithium-ion secondary batteries, nickel-metal hydride batteries, and nickel-cadmium batteries, can be used as the secondary battery cells 1.

[0039] Each secondary battery cell 1 has a positive electrode and a negative electrode. The positive or negative electrode terminal is preferably provided on one end surface of the secondary battery cell 1. In the examples shown in Figures 7 to 9, a positive electrode terminal is provided on one end surface of the secondary battery cell 1, and the other surface of the outer can serves as the negative electrode. In the example shown in Figure 7, each secondary battery cell 1 is held by a battery holder 40 in an orientation such that the positive electrodes of all secondary battery cells 1 are on the same side (the front side in the figure). In this case, only one end surface of the secondary battery cell (here, the positive electrode side) may be covered by the holder case, and the other end surface may be exposed. However, by covering both sides of the secondary battery cell with the holder case, it is possible to accommodate situations in which the positive and negative electrodes of the stacked secondary battery cells are randomly arranged on the end surfaces.

[0040] (Holder openings 34) The holder case 31 also has holder openings 34 formed on its top and bottom surfaces. Cooling air can be taken into the holder case 31 through the holder openings 34 opened on the top and bottom of the holder case 31 and discharged after heat exchange. Furthermore, by opening the holder openings 34 on each of the opposing surfaces, the cooling air can be made to flow smoothly in a straight line.

[0041] Each holder opening 34 preferably extends in a direction intersecting the longitudinal direction of the rechargeable battery cells 1. This allows the holder openings 34 to be opened in the direction in which the rechargeable battery cells 1 are stacked, and many of the cylindrical storage tubes 42 are exposed from the holder case 31, improving heat dissipation performance. In the examples shown in Figures 6 and 12, approximately five battery holders 40 and ten cylindrical storage tubes 42 are partially exposed from the holder case 31 through the holder openings 34.

[0042] 6, the first holder case 31A and the second holder case 31B, which are divided into two parts, each have a holder opening 34. With this configuration, the holder openings 34 are formed in multiple slits, and the opening width of each slit is narrowed, preventing foreign matter from entering the holder case 31. Furthermore, by forming multiple slits, the opening area of ​​the holder openings 34 is widened, preventing obstruction to the intake and exhaust of cooling air. Note that three or more holder openings may be provided on the top and bottom surfaces of the holder case. Alternatively, only one holder opening may be provided.

[0043] Furthermore, the two holder openings 34 opened on the top surface of the holder case 31 are connected to the partition plate openings 21 of the partition plate 20. In the example of Fig. 4, one partition plate opening 21 includes two holder openings 34. However, one partition plate opening 21 may include all of the holder openings 34.

[0044] (Elastic Divider Plate Body 22) Furthermore, by interposing an elastic divider plate body 22 between each divider plate 20 and the battery block 30, a waterproof structure for the divider plate opening 21 is achieved. That is, the elastic divider plate body 22 closes the gap between the divider plate 20 and the periphery of the holder opening 34 on the top surface of the holder case 31, preventing water from seeping in through the gap and submerging the terminals of the rechargeable battery cells 1. The elastic divider plate body 22 is formed in a ring shape that is slightly larger than the divider plate opening 21. In the example shown in FIG. 4 , the elastic divider plate body 22 provided in each divider plate opening 21 is formed in a rectangular shape. Such elastic divider plate bodies 22 can be made of rubber packing, waterproof double-sided tape, or the like.

[0045] Furthermore, as shown in Figures 4 and 13, an elastic body 23 similar to the partition plate elastic body 22 is interposed between the lower inner wall of the exterior case 10 and the bottom surface of the battery block 30, i.e., the holder case 31. The elastic body 23 is made of rubber packing, waterproof double-sided tape, or the like, and is installed around the two holder openings 34 on the exterior case air intake 13 side of the lower inner wall of the exterior case 10, thereby achieving a waterproof structure for the internal space of the exterior case 10 around the outer periphery of the battery block 30. In other words, the space between the exterior case 10 and the holder case 31 where multiple lead plates 5 are installed is made waterproof. In the horizontal cross-sectional view of Figure 11, the waterproof area is indicated by a dashed line.

[0046] (First Cooling Air Path FP1) The holder case 31 forms a first cooling air path FP1 that allows cooling air to flow between the inner surface of the holder case 31 and the surfaces of the battery holders 40. The exterior case 10 also forms an exterior case exhaust port 14 that communicates with the first cooling air path FP1. This configuration allows cooling air to be taken in from the outside through the first cooling air path FP1 and flowed over the surfaces of the battery holders 40, enabling efficient cooling.

[0047] In the example shown in Figure 13, the battery holder 40 covers at least the middle portion of each battery cell excluding the terminals. Meanwhile, the holder case 31 forms a first cooling air passage FP1 between the surface side of the battery holder 40 that covers the middle portion of the battery cell and the inner side of the holder case 31. The holder case 31 also has a holder opening 34 that communicates with the first cooling air passage FP1. This holder opening 34 communicates with an external opening. With this configuration, cooling air flows to the outer surface of the battery holder 40 that covers the middle portion of the secondary battery cell 1, enabling efficient cooling of the secondary battery cell 1.

[0048] The exterior case 10 has an exterior case air inlet 13 and an exterior case exhaust vent 14. Cooling air is drawn in through the exterior case air inlet 13 and introduced into the exterior case 10, where it undergoes heat exchange and is then exhausted through the exterior case exhaust vent 14. For example, a fan or the like is provided to forcibly circulate the cooling air. It is preferable that the exterior case air inlet 13 and the exterior case exhaust vent 14 be provided on different sides of the exterior case 10 so that the cooling air can be smoothly introduced into and exhausted from the exterior case 10. In the example shown in FIG. 2 , the exterior case air inlet 13 is opened on the bottom side of the exterior case 10, and the exterior case exhaust vent 14 is opened on the upper side of the back surface of the exterior case 10.

[0049] It is preferable that the exterior case air intake port 13 and the exterior case air exhaust port 14 are opened in the form of multiple slits. This narrows the opening of each slit to prevent the intrusion of foreign matter, while providing multiple slits makes it possible to increase the total opening area.

[0050] The exterior case air intake 13 is preferably located at a position corresponding to the middle of the battery holder 40. This exposes the middle of the battery holder 40 through the exterior case air intake 13 and the holder opening 34 on the bottom surface of the holder case 31. As a result, fresh cooling air is drawn into the exterior case 10 through the exterior case air intake 13 and the holder opening 34, allowing efficient cooling of the middle of the rechargeable battery cells 1 housed in the battery holder 40. In the example shown in FIG. 2 , the exterior case air intake 13 on the bottom surface of the exterior case 10 draws cooling air from below to the middle of the rechargeable battery cells 1 on the bottom surface of the battery holder 40. This cooling air flows through the first cooling air path FP1 formed in the gap between the battery holder 40 and the holder case 31, as shown in FIG. 13 , and reaches the top of the battery holder 40 while exchanging heat with the battery holder 40. The air is then guided through the holder openings 34 on the top surface of the holder case 31 and the partition plate openings 21 in the partition plate 20 to the top of the outer case 10, or into the interior of the upper case 11 in FIG. 13 , and then discharged through the outer case exhaust port 14 that opens above the back surface of the outer case 10. In this way, cooling air flows into the interior of the outer case 10 through the first cooling air path FP1, directly cooling the middle portions of the secondary battery cells 1 housed in the thermally conductive battery holders 40.

[0051] (Second Cooling Air Path FP2) In a configuration in which multiple battery holders 40 are stacked, it is preferable to provide gaps between the divided battery holders 40. These gaps serve as second cooling air paths FP2, through which cooling air flows. The second cooling air paths FP2 also communicate with the exterior case air intake 13 and the exterior case air exhaust 14 of the exterior case 10. This allows for the formation of second cooling air paths FP2, which allow cooling air to flow in the middle of the battery holder 40, in addition to the first cooling air paths FP1 in the gaps between both side surfaces of the battery holder 40 and the inner surface of the holder case 31, at the crossing plane that intersects with the longitudinal direction of the rechargeable battery cells 1, thereby further improving cooling performance. In the example shown in Figures 10 and 14, six second cooling air paths FP2 are formed in the gaps between adjacent battery holders 40 for seven battery holders 40. The second cooling air paths FP2 are routed into the first case through the holder openings 34 of the holder case 31. The heat is also released to the outside from the power supply device 100 through the exterior case exhaust port 14 opened in the first case.

[0052] (Waterproof Structure) While cooling air is taken in and exhausted through the exterior case air intake vents 13 and exterior case exhaust vents 14 opened in the exterior case 10, it is necessary to prevent unintended electrical conduction, particularly at the terminals, of the numerous rechargeable battery cells 1 housed in the exterior case 10. For this reason, a waterproof structure is provided between the holder case 31 and each battery holder 40 to waterproof the area including the terminals of the rechargeable battery cells 1. The waterproof structure waterproofs the terminals of the multiple rechargeable battery cells 1 held by the battery holders 40, thereby waterproofing the terminals. At the same time, cooling air can be taken in from the outside through the cooling air paths between the battery holders 40, enabling efficient cooling.

[0053] (Sealing member 50) To provide a waterproof structure, a sealing member 50 can be interposed between the periphery of the battery holder 40 and the inner surface of the holder case 31. An elastic material such as packing can be used for this sealing member 50. In the examples shown in Figures 8, 9, 11, etc., the sealing member 50 is wrapped around the edge of the battery holder 40. However, the sealing member is not limited to this configuration; for example, a sealing member can be placed in advance on each cylindrical portion of the holder case.

[0054] 11 , the area corresponding to the end of the secondary battery cell 1, the area surrounded by the dashed line in the figure, is waterproofed with a seal member 50. Meanwhile, the middle side portion of the secondary battery cell 1 is exposed to the battery holder 40, and is efficiently cooled by heat exchange with the cooling air flowing through the second cooling air path FP2 and the second cooling air path FP3. By waterproofing the area between the battery holder 40 and the holder case 31 in this way, it is possible to directly air-cool the area around each secondary battery cell 1 while simplifying the waterproof structure.

[0055] In a structure that uses air cooling by flowing cooling air into the exterior case, an opening is provided in the exterior case to ensure an air flow path. However, to prevent unintended short circuits of the rechargeable battery cells housed inside the exterior case, a waterproof structure is required to protect the electrode portions of each rechargeable battery cell from external water, etc. This requires a complex structure because the rechargeable battery cells housed inside must be waterproofed while still having an opening in the exterior case. In contrast, the power supply device 100 according to this embodiment has a simple structure in which the belly portion of the rechargeable battery cell 1 is covered with a highly thermally conductive material such as metal, while both ends of the rechargeable battery cell 1 are covered with a holder case 31 made of resin or the like, providing a waterproof structure between the middle and both ends. This achieves the contradictory requirements of air cooling via an open exterior case 10 while protecting the parts that require waterproofing with a waterproof structure.

[0056] The above configuration also makes the circuit board 3 waterproof. That is, the insulating structure isolates the circuit board 3 from the cooling air path provided between the exterior case air intake vent 13 and the exterior case air exhaust vent 14 for circulating cooling air, and the waterproof structure also makes the circuit board 3 waterproof. This effectively prevents short circuits between the terminals of the secondary battery cells 1 and unintended electrical continuity of the circuit board 3.

[0057] In the above examples, the power supply device is attached to the electrical equipment to be driven and supplies power to the electrical equipment. When the remaining capacity of the power supply device becomes low or when the power supply device deteriorates over time, the power supply device can be replaced to continue using the electrical equipment. However, the present invention is not limited to replaceable power supply devices that mainly house secondary battery cells, but can also be applied to configurations in which secondary battery cells are housed within the housing of the electrical equipment. In this disclosure, a power supply device is sufficient as long as it houses secondary battery cells in a case, and also includes power supply devices that incorporate secondary battery cells for driving the electrical equipment within the housing of the electrical equipment itself. In other words, the present invention is not limited to replaceable power supply devices, but can also be applied to electrical equipment that incorporates secondary battery cells.

[0058] The power supply device according to the present disclosure can be suitably used as a driving power source for assisted bicycles, self-propelled delivery robots, electric carts for delivery and golf courses, electric scooters, construction machinery, hybrid vehicles, electric vehicles, and other vehicles. It can also be used as a power source for portable electrical devices such as radios, electric cleaners, and power tools. It can also be used as a cooling mechanism for electrical devices with built-in heating elements, and can be used as a stationary power storage device, for example, a power supply device for home, business, or factory use, or as a backup power source for servers.

[0059] DESCRIPTION OF SYMBOLS 100...power supply device 1...secondary battery cell 2...battery module 3...circuit board 4...board holder 5...lead plate 10...exterior case 11...upper case 12...lower case 13...exterior case intake port 14...exterior case exhaust port 20...partition plate 21...partition plate opening 22...partition plate elastic body 23...elastic body 30...battery block 31...holder case 31A...first holder case 31B...second holder case 32...case cylindrical portion 34...holder opening 40...battery holder 42...storage cylinder 50...sealing member FP1...first cooling air path FP2...second cooling air path

Claims

1. A power supply device comprising: a plurality of secondary battery cells each having a terminal; a thermally conductive battery holder that houses the plurality of secondary battery cells; a holder case that houses the battery holder; and an outer case that houses the holder case, wherein the power supply device has a waterproof structure between the holder case and the battery holder that waterproofs an area including at least the terminals of the plurality of secondary battery cells housed in the battery holder, the holder case forms a first cooling air path between the inner surface of the holder case and the surface of the battery holder for allowing cooling air to flow, and the outer case forms an outer case exhaust port that communicates with the first cooling air path.

2. A power supply device as described in claim 1, wherein the battery holder covers at least the middle portion of each of a plurality of secondary battery cells excluding the terminals, the holder case forms the first cooling air passage between the surface of the battery holder covering the middle portions of the plurality of secondary battery cells and the inner surface of the holder case, the holder case has a holder opening which is connected to the first cooling air passage, and the holder opening is connected to the outer case exhaust port.

3. A power supply device as claimed in claim 2, wherein the outer case has an outer case intake port which communicates with the first cooling air path and is opened at a location different from the outer case exhaust port, and a middle portion of the battery holder is exposed through the outer case intake port.

4. A power supply device as described in claim 2, wherein each of the plurality of secondary battery cells is a cylindrical outer can, at least one end face of the cylindrical outer can serves as the terminal, and the holder case is divided so as to cover each of the longitudinal end faces of the plurality of secondary battery cells.

5. A power supply device as claimed in claim 2, wherein the battery holder is provided with a storage cylinder that at least partially stores the secondary battery cells, and the holder opening is extended in a direction intersecting the longitudinal direction of the multiple secondary battery cells.

6. A power supply device as claimed in claim 5, wherein the length of the storage cylinder of the battery holder is shorter than that of the secondary battery cells, and the ends of the secondary battery cells are exposed from the storage cylinder.

7. A power supply device as claimed in any one of claims 1 to 6, wherein the holder case houses a plurality of the battery holders, the holder case is provided with a second cooling air passage between the plurality of battery holders, and the exterior case exhaust port is connected to the second cooling air passage.

8. A power supply device according to any one of claims 1 to 6, wherein the waterproof structure is a seal member interposed between the periphery of the battery holder and the inner surface of the holder case.

9. A power supply device according to any one of claims 1 to 6, wherein the holder case is made of resin, and the battery holder is made of a material having a higher thermal conductivity than the resin that constitutes the holder case.

10. A power supply device according to any one of claims 1 to 6, further comprising a circuit board electrically connected to said plurality of secondary battery cells, said circuit board being waterproofed by said waterproof structure.

11. A power supply device as claimed in any one of claims 1 to 6, further comprising a plurality of lead plates respectively installed on both end surfaces of the secondary battery cells of the holder case and electrically connecting the end surface electrodes of the plurality of secondary battery cells, a first elastic body being interposed between the upper surface of the holder case and the upper inner wall of the exterior case, a second elastic body being interposed between the lower surface of the holder case and the lower inner wall of the exterior case, and the space between the exterior case and the holder case in which the plurality of lead plates are installed being waterproofed by a waterproof structure.

12. A power supply device comprising: a plurality of columnar secondary battery cells each having a terminal; a plurality of thermally conductive battery holders for housing the plurality of secondary battery cells; a holder case for housing the plurality of battery holders; and an outer case for housing the holder case, wherein a sealing member is wound around each of the plurality of battery holders near the edge of the plurality of secondary battery cells between the periphery of each of the plurality of battery holders and the inner surface of the holder case, the holder case forming a first cooling air passage between the surface of the battery holder covering at least the middle portions of the plurality of secondary battery cells other than the terminals and the inner surface of the holder case, and the outer case forming an outer case exhaust port communicating with the first cooling air passage.

13. A power supply device, wherein the holder case has a holder opening communicating with the first cooling air path, and the holder opening communicates with the outer case exhaust port.

14. A power supply device as described in claim 13, wherein the outer case has an outer case intake port that communicates with the first cooling air path at a location different from the outer case exhaust port, and a middle portion of the battery holder is exposed through the outer case intake port.

15. A power supply device as described in claim 13, wherein each of the plurality of secondary battery cells is a cylindrical exterior can, at least one end face of the cylindrical exterior can serves as the terminal, and the holder case is divided so as to cover each of the longitudinal end faces of the plurality of secondary battery cells.

16. A power supply device as described in claim 13, wherein each of the battery holders is provided with a storage tube that at least partially stores one of the secondary battery cells, and the holder opening is extended in a direction intersecting the longitudinal direction of the multiple secondary battery cells.

17. A power supply device as claimed in claim 16, wherein the length of the storage cylinder of each of the battery holders is shorter than that of the secondary battery cells, and the ends of the secondary battery cells are exposed from the storage cylinder.

18. A power supply device as claimed in any one of claims 12 to 17, wherein the holder case is provided with a second cooling air passage between the plurality of battery holders, and the exterior case exhaust port is connected to the second cooling air passage.

19. A power supply device as claimed in any one of claims 12 to 17, wherein the holder case is made of resin, and each of the battery holders is made of a material having a higher thermal conductivity than the resin that constitutes the holder case.

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