Power supply device

Abstract

A power supply device (100) comprises: a plurality of secondary battery cells (1) each having an end surface; and an exterior case (10) for accommodating the plurality of secondary battery cells (1). The exterior case (10) has a gas discharge hole (13) opened in a part of the surface of the case. In the exterior case (10), a metal plate material (50) is disposed overlapping the gas discharge hole (13). In the plate material (50), a plurality of small holes (52), each of which is smaller than the end surface of a corresponding secondary battery cell (1), are opened, and the gas discharge hole (13) and the plurality of small holes (52) are formed so as not to overlap each other.

Description

power supply

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

[0002] Power supply devices that have multiple rechargeable secondary battery cells, such as lithium-ion secondary batteries, connected in series or parallel are used as power sources for electrical equipment. In recent years, with the demand for higher output and capacity of power supply devices, the number of secondary battery cells used in power supply devices has tended to increase.

[0003] In secondary battery cells, the inside of the outer can may become highly pressurized due to some abnormality. Therefore, the outer can is provided with a safety valve that opens in response to an increase in internal pressure. When the internal pressure increases, this safety valve opens to discharge the high-temperature, high-pressure gas inside the outer can from the outer can. In this case, the high-temperature, high-pressure gas discharged from the outer can must be discharged to the outside of the power supply device. A structure is required to prevent the gas from igniting and causing a flame to leak outside the power supply device. For example, as shown in Figure 18, a large flame-extinguishing duct space 655 can be provided in the gas discharge path to lower the temperature of the ejected gas, which is a heat source for a fire.

[0004] However, providing such a configuration makes the internal structure of the power supply device complex, which increases costs and requires a corresponding amount of installation space, resulting in problems such as an increase in the size of the power supply device.

[0005] Japanese Patent Application Laid-Open No. 2009-212081

[0006] The present disclosure provides a power supply device with a simplified structure that can safely discharge gas to the outside when an abnormality occurs in a secondary battery cell.

[0007] A power supply device according to one embodiment of the present disclosure includes a plurality of secondary battery cells, each having an end face, and an exterior case that houses the plurality of secondary battery cells. The exterior case has a gas exhaust hole in a portion of its surface. Inside the exterior case, a metal plate is disposed so as to overlap the gas exhaust hole. The plate has a plurality of small holes, each smaller than the end face of the secondary battery cell, and the gas exhaust hole and the small holes do not overlap.

[0008] According to the power supply device according to one embodiment of the present disclosure, it is possible to simplify the structure that can safely discharge gas to the outside when an abnormality occurs in a secondary battery cell.

[0009] FIG. 1 is a perspective view showing a power supply device according to a first embodiment. FIG. 2 is a perspective view of the power supply device of FIG. 1 as seen from the rear side. FIG. 3 is a longitudinal cross-sectional view of the power supply device of FIG. 1 taken along line III-III. FIG. 4 is an exploded perspective view of the power supply device of FIG. 1. FIG. 5 is an exploded perspective view of the power supply device of FIG. 4 as seen from the rear side. FIG. 6 is a further exploded perspective view of the power supply device of FIG. 4. FIG. 7 is a further exploded perspective view of the power supply device of FIG. 6. FIG. 8 is an exploded perspective view of the power supply device of FIG. 6 as seen obliquely from below. FIG. 9 is an exploded perspective view of the battery block of FIG. 6. FIG. 10 is a front view of the battery module of FIG. 4. FIG. 11 is a rear view of the battery module of FIG. 5. FIG. 12 is an exploded perspective view with the label removed from the outer case. FIG. 13 is an enlarged cross-sectional view of a main portion of FIG. 3. FIG. 14 is a cross-sectional perspective view of the top surface of the outer case of FIG. 13 as seen obliquely from below on the inner side. FIG. 15 is a bottom view of the top surface of the outer case of FIG. 13 as seen from the inner side. FIG. 16 is a cross-sectional view of a power supply device according to a comparative example. FIG. 17 is an enlarged cross-sectional view of the power supply device of FIG. 16 . FIG. 18 is a bottom view of the top surface of the exterior case of the power supply device of FIG. 16 viewed from the inside. FIG. 19 is a diagram showing the gas exhaust path of the power supply device of FIG. 16 . FIG. 20 is a cross-sectional view showing the ventilation path for cooling air in the power supply device of FIG. 3 . FIG. 21 is an enlarged cross-sectional view of a main portion of the power supply device of FIG. 3 . FIG. 22 is a perspective view of the spacer portion of FIG. 7 viewed obliquely from below. FIG. 23 is an enlarged cross-sectional view of a main portion of the power supply device of FIG. 3 . FIG. 24 is an enlarged cross-sectional view of a main portion of the power supply device of FIG. 3 . FIG. 25 is a cross-sectional view showing how high-pressure gas is exhausted in the power supply device of FIG. 3 . FIG. 26 is an enlarged perspective view of the power supply device of FIG. 8 . FIG. 27 is an exploded perspective view of the first battery block of FIG. 26 . FIG. 28 is an enlarged perspective view showing the top surface of the second battery block. FIG. 29 is an exploded perspective view of the second battery block of FIG. 28 . FIG. 30 is a cross-sectional view of the power supply device of FIG. 1 taken along line XXII-XXII.

[0010] A power supply device according to one embodiment of the present disclosure includes a plurality of secondary battery cells, each having an end face, and an exterior case that houses the plurality of secondary battery cells. The exterior case has a gas exhaust hole in a portion of its surface. Inside the exterior case, a metal plate is disposed so as to overlap the gas exhaust hole. The plate has a plurality of small holes, each smaller than the end face of the secondary battery cell, and the gas exhaust hole and the small holes do not overlap.

[0011] According to the power supply device of one embodiment of the present disclosure, even if high-temperature, high-pressure gas is exhausted from one of the secondary battery cells, it can be safely exhausted to the outside of the power supply device through the gas exhaust hole and the small hole in the metal plate, which has the advantage of simplifying the complex structure for reducing the gas temperature and pressure.

[0012] The embodiments of the present disclosure may be specified by the following configurations and features.

[0013] In another aspect of the power supply device of the present disclosure, in the above aspect, the plate material is formed in a flat plate shape, the plurality of small holes are formed in a ring shape in a portion of the plate except for a central region, and the gas exhaust hole is arranged to overlap with the central region of the plate material. With this configuration, the gas exhaust hole and the plurality of small holes are arranged so as not to overlap, preventing the gas that passes through the plurality of small holes from being directly released to the outside of the exterior case, and allowing the gas to be released in a state of reduced pressure and temperature, thereby improving safety.

[0014] In addition, in a power supply device according to another aspect of the present disclosure, in any of the above aspects, each of the multiple secondary battery cells has a cylindrical outer can, and one side of the outer can is provided with a safety valve that opens in response to an increase in internal pressure of the outer can. The total opening area of ​​the multiple small holes is larger than the opening area of ​​the safety valve when it is open. With this configuration, even if the safety valve of any one of the secondary battery cells opens, the total area of ​​the small holes that release gas is larger than the opening area of ​​the safety valve, thereby preventing an increase in pressure inside the power supply device and reducing the risk of rupture due to an increase in internal pressure.

[0015] Furthermore, in another aspect of the power supply device according to the present disclosure, in any of the above aspects, the outer case is formed in a box shape extending in one direction and includes a top surface, a bottom surface spaced from the top surface, and side surfaces connecting the top surface and the bottom surface. The outer case has a gas exhaust hole in the top surface, and defines a gas exhaust path that, when gas is released from one of the multiple secondary battery cells inside the outer case, guides the gas in the longitudinal direction of the outer case, then along the inner surface of the side surface to the inner surface of the top surface, and then guides it to the gas exhaust hole. With this configuration, high-pressure gas released from the outer can of the secondary battery cell is not directly discharged through the gas exhaust path, but is first guided longitudinally inside the outer case, then along the side surface to the top surface, and then discharged through the gas exhaust hole. With this configuration, the pressure and temperature of the gas are reduced to a certain extent inside the outer case before being discharged to the outside, thereby improving safety.

[0016] Furthermore, in the power supply device according to another aspect of the present disclosure, in any of the above aspects, the equivalent diameter of the entire plurality of small holes is set to be equal to the equivalent diameter when the safety valve is opened.

[0017] Furthermore, in the power supply device according to another aspect of the present disclosure, in any of the above aspects, the gas exhaust hole is provided in the middle of the top surface.

[0018] Furthermore, in the power supply device according to another aspect of the present disclosure, in any one of the above aspects, the opening area of ​​each of the plurality of small holes is set to φ2 mm or less.

[0019] Furthermore, in the power supply device according to another aspect of the present disclosure, in any of the above aspects, a flame-extinguishing duct space is formed between the plurality of small holes and the gas exhaust hole.

[0020] Furthermore, in the power supply device according to another aspect of the present disclosure, in any of the above aspects, the multiple secondary battery cells are arranged in an orientation such that the side on which the safety valve is provided faces the flame-extinguishing duct space.

[0021] Furthermore, the power supply device according to another aspect of the present disclosure is any of the above-described aspects, further including a label attached to close the gas exhaust hole of the exterior case.

[0022] Furthermore, in the power supply device according to another aspect of the present disclosure, in any of the above aspects, the plate material is formed in a circular shape, and a plurality of small holes are formed in the circular plate material in a concentric pattern.

[0023] Furthermore, in the power supply device according to another aspect of the present disclosure, in any one of the above aspects, the plate material has a metal mesh structure.

[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 power supply device of the present disclosure can be used as a driving power source for mobile objects such as electric carts, electric scooters, and assisted bicycles, and as a power source for portable electrical devices such as radios, electric cleaners, and power tools. Alternatively, the power supply device of the present disclosure can be used as a backup power source for servers in stationary power storage applications, as a power supply device for home, office, and factory use, and even as a driving power source for vehicles such as hybrid cars and electric automobiles. Below, a power supply device 100 used as a driving power source for an electric cart will be described as one embodiment of the present disclosure.

[0026] [Embodiment 1] A power supply device 100 according to Embodiment 1 of the present disclosure will be described with reference to Figures 1 to 30. 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 as seen from the rear, Figure 3 is a longitudinal cross-sectional view of the power supply device 100 of Figure 1 taken along line III-III, and Figure 4 is an exploded perspective view of the power supply device 100 of Figure 1. Also, Figure 5 is an exploded perspective view of the power supply device 100 of Figure 4 as seen from the rear, Figure 6 is a further exploded perspective view of the power supply device 100 of Figure 4, Figure 7 is a further exploded perspective view of the power supply device 100 of Figure 6, and Figure 8 is an exploded perspective view of the power supply device 100 of Figure 6 as seen obliquely from below. Also, Figure 9 is an exploded perspective view of the battery block 20 of Figure 6, Figure 10 is a front view of the battery module 2 of Figure 4, and Figure 11 is a rear view of the battery module 2 of Figure 5. Fig. 12 is an exploded perspective view with the label 5 removed from the exterior case 10, Fig. 13 is an enlarged cross-sectional view of the main part of Fig. 3, Fig. 14 is a cross-sectional perspective view of the top surface 14 of the exterior case 10 of Fig. 13 viewed from diagonally below on the inner surface, and Fig. 15 is a bottom view of the top surface 14 of the exterior case 10 of Fig. 13 viewed from the inner surface. Fig. 16 is a cross-sectional view showing a power supply device 600 according to a comparative example, Fig. 17 is an enlarged cross-sectional view of the power supply device 600 of Fig. 16, Fig. 18 is a bottom view of the top surface 614 of the exterior case 610 of the power supply device 600 of Fig. 16 viewed from the inner surface, and Fig. 19 is a diagram showing a gas exhaust path of the power supply device 600 of Fig. 16. Fig. 20 is a cross-sectional view showing the ventilation path for cooling air in the power supply device 100 of Fig. 3, Fig. 21 is an enlarged cross-sectional view of a main portion of the power supply device 100 of Fig. 3, Fig. 22 is a perspective view of the spacer portion 30 of Fig. 7 viewed diagonally from below, and Fig. 23 is an enlarged cross-sectional view of a main portion of the power supply device 100 of Fig. 3. Fig. 24 is an enlarged cross-sectional view of a main portion of the power supply device 100 of Fig. 3, Fig. 25 is a cross-sectional view showing how high-pressure gas is discharged in the power supply device 100 of Fig. 3, Fig. 26 is an enlarged perspective view of the power supply device 100 of Fig. 8, and Fig. 27 is an exploded perspective view of the first battery block 20A of Fig. 26. Fig. 28 is an enlarged perspective view showing the top surface of the second battery block 20B, Fig. 29 is an exploded perspective view of the second battery block 20B of Fig. 28, and Fig. 30 is a cross-sectional view of the power supply device 100 of Fig. 1 taken along line XXII-XXII. The power supply device 100 shown in these figures comprises an outer case 10 , a battery module 2 , and a circuit board 3 .

[0027] (External Case 10) The external case 10 houses the battery modules 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 Figures 1 to 3, the external case 10 has a box-like appearance that extends in one direction. The box-shaped external case 10 is composed of a top surface 14 and a bottom surface 15 that are spaced apart from each other above and below, and side surfaces 16 that connect these surfaces. The external case 10 also has a case inlet 17 and a case outlet 18 opening at each end surface in the longitudinal direction.

[0028] As shown in Figures 3 to 7, the exterior case 10 is divided into an upper case 11 and a lower case 12. The exterior case 10 is preferably made of a resin with excellent insulating properties, such as polycarbonate or a PC-ABS (Polycarbonate-Acrylonitrile Butadiene Styrene resin) alloy, but may also be made of a metal material such as aluminum or its alloy. As shown in Figures 4 to 7, an internal space is provided inside the exterior case 10 to house the battery module 2 and circuit board 3.

[0029] (Battery module 2) The battery module 2, also called a core pack, is composed of multiple battery blocks 20. In the example shown in Figures 6 to 8, the battery module 2 is composed of a first battery block 20A and a second battery block 20B. The first battery block 20A and the second battery block 20B are each composed of multiple secondary battery cells 1. Here, of the multiple secondary battery cells 1, the secondary battery cell 1 housed in the first battery block 20A is referred to as the first secondary battery cell 1A, and the secondary battery cell 1 housed in the second battery block 20B is referred to as the second secondary battery cell 1B.

[0030] The multiple secondary battery cells 1 are connected in series or in parallel via lead plates 4. The number of series connections and the number of parallel connections can be set arbitrarily according to the required specifications. Preferably, the first battery block 20A and the second battery block 20B use the same number of secondary battery cells 1. It is also preferable that the first battery block 20A and the second battery block 20B have the same number of series connections and parallel connections. In the examples shown in FIGS. 3 and 5 , the first battery block 20A and the second battery block 20B each use a total of 90 first secondary battery cells 1A and 90 second secondary battery cells 1B (9 series x 10 parallel connections), and the entire battery module 2 uses a total of 180 secondary battery cells 1 (18 series x 10 parallel connections). However, the first battery block 20A, the second battery block 20B, and the battery module 2 are not limited to this configuration.

[0031] Each battery block 20 includes multiple rechargeable battery cells 1. For example, the battery block 20 includes battery holders 21 that house the rechargeable battery cells 1. Specifically, the first battery block 20A includes a first battery holder 21A that houses multiple first rechargeable battery cells 1A. The second battery block 20B includes a second battery holder 21B that houses multiple second rechargeable battery cells 1B. Each battery holder 21 includes multiple storage cylinders that house the individual rechargeable battery cells 1. For example, each battery holder 21 is divided into two, an upper and lower section, and the two storage cylinders hold the rechargeable battery cells 1 from above and below. Such battery holders 21 can be made of resin such as polycarbonate, which has excellent insulating properties.

[0032] 3, 9, and other examples, each battery block 20 is configured with 90 secondary battery cells 1, but in the present disclosure, the number of secondary battery cells configuring each battery block is not limited to this and can be any number. Also, in the present disclosure, the number of secondary battery cells may be changed in some battery blocks. Furthermore, in the examples shown in FIGS. 6 to 8, an example is described in which a battery module 2 is configured with two battery blocks, a first battery block 20A and a second battery block 20B. However, it goes without saying that the present disclosure does not limit the number of battery blocks to two and may include three or more.

[0033] (Secondary battery cells 1) Each secondary battery cell 1 can be a secondary battery cell with a cylindrical or rectangular outer shape. In the examples shown in Figures 3 and 9, cylindrical secondary battery cells 1 are used in a staggered arrangement in a vertical orientation. 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.

[0034] Each secondary battery cell 1 has a positive and negative electrode, which are preferably provided on one end surface of the secondary battery cell 1. The secondary battery cell 1 may be any known secondary battery, such as a lithium-ion secondary battery, a nickel-metal hydride battery, or a nickel-cadmium battery.

[0035] (Safety valve 1a) The exterior can of each secondary battery cell 1 is provided with a safety valve 1a. The safety valve 1a opens in response to an increase in internal pressure of the exterior can, releasing gas inside the exterior can to the outside. For example, as shown in Figure 9, this type of safety valve 1a is provided on the positive electrode side of the secondary battery cell 1.

[0036] (Gas vent hole 13) Meanwhile, the exterior case 10 has a gas vent hole 13 formed in a part thereof for releasing high-pressure gas to the outside when the safety valve 1a of the secondary battery cell 1 is opened and the gas is discharged, as shown in Figures 10, 11, etc. In the example of Figures 1 to 5, etc., the gas vent hole 13 is provided near the center of the top surface 14 of the exterior case 10 (which can also be said to be the middle of the top surface 14).

[0037] (Label 5) The power supply device 100 may also include a member that blocks the gas exhaust hole 13. In the example shown in the exploded perspective view of Figure 12, a label 5 is attached to the top surface 14 of the exterior case 10 to block the gas exhaust hole 13.

[0038] (Plate 50) Inside the exterior case 10, a metal plate 50 is positioned overlapping the gas exhaust hole 13. As shown in FIGS. 12 to 14 , the outer surface of the top surface 14 of the exterior case 10, where the gas exhaust hole 13 is provided, is covered with a label 5, while the plate 50 is provided on the inner surface. The plate 50 engages with an engaging member 19 formed to protrude from the inner surface of the exterior case 10, and is attached to the interior of the exterior case 10 with its position relative to the gas exhaust hole 13. The plate 50 has a plurality of small holes 52. The opening area of ​​each small hole 52 is smaller than the end face of the secondary battery cell 1. The opening area of ​​each small hole 52 is also smaller than the opening area of ​​one safety valve 1a of the secondary battery cell 1 when it is open. Preferably, the total opening area of ​​the small holes 52 is larger than the opening area of ​​one safety valve 1a of the secondary battery cell 1 when it is open. On the other hand, it is preferable to make the total equivalent diameter of the small holes 52 smaller than the equivalent diameter of one safety valve 1a of the secondary battery cell 1 when it is open. Here, the equivalent diameter is a representative length that indicates the diameter of a collection of circular pipes equivalent to that of the flow path in terms of flow, and is also called the equivalent (diameter) diameter. The equivalent diameter De is calculated using the following formula: De = 4Af / Wp, where Af is the flow path cross-sectional area and Wp is the wetted perimeter length (the length of the wall surface at the cross section). For example, when 104 small holes 52 with a diameter of 2 mm are opened, the equivalent diameter is equivalent to a safety valve with a diameter of 13 mm, and preferably can be set to a diameter of 13 x 3 / 4.

[0039] 13 to 15, the multiple small holes 52 are positioned so as not to overlap with the gas exhaust holes 13. With this configuration, even if high-temperature, high-pressure gas is exhausted from one of the secondary battery cells 1, it can be safely exhausted to the outside of the power supply device 100 through the gas exhaust holes 13 and the small holes 52 in the metal plate 50, which has the advantage of simplifying the complex structure for reducing the gas temperature and pressure.

[0040] To maintain safety even if the internal pressure of the exterior can becomes high due to some abnormality in the secondary battery cell, the exterior can is provided with a safety valve that opens in response to an increase in internal pressure. When the internal pressure increases, this safety valve opens to discharge high-temperature, high-pressure gas from the exterior can. In this case, the high-temperature, high-pressure gas discharged from the exterior can must be discharged from the exterior case after its pressure and temperature have been reduced to a certain extent so that it can be discharged to the outside of the power supply device. For example, in a power supply device 600 according to a comparative example shown in the cross-sectional view of FIG. 16 , as shown in the enlarged cross-sectional view of FIG. 17 and the bottom view of FIG. 18 , a flame-extinguishing duct space 655 is provided on the inner side of the top surface 614 of the exterior case 610. This flame-extinguishing duct space 655 reduces the pressure and temperature of high-temperature, high-pressure gas from the secondary battery cell 601, guided within a frame surrounded by cushioning material 660 as shown in FIG. 18 , by passing it through a metal plate 662 equipped with a metal mesh 661. Furthermore, the gas that has passed through metal plate 662 passes through flame-extinguishing duct space 655 and heads toward gas exhaust hole 613, as shown in FIG. 17. At this time, flame-extinguishing duct space 655 is partitioned in the middle by multiple partitions 664, as shown in FIG. 18, so the gas branches left and right and changes direction as it travels, further reducing its pressure and temperature. Finally, as shown in FIG. 19, the gas is released to the outside in a state of reduced pressure and temperature from gas exhaust hole 613 opened in top surface 614 of exterior case 610. However, providing such a complex configuration complicates the internal structure of power supply unit 600, increases costs, and requires a considerable amount of installation space, resulting in problems such as an increase in the size of the power supply unit.

[0041] In contrast, in the power supply device 100 of embodiment 1, as described above, a simpler structure such as that shown in FIG. 15 and the like can effectively reduce the gas pressure and temperature, making it possible to simplify the configuration of the power supply device 100, reduce its height, and reduce manufacturing costs.

[0042] The plate material 50 is preferably formed in a flat plate shape. The outer shape of the plate material 50 can be circular, polygonal, rectangular, or the like. In the examples of Figures 12, 14, 15, etc., the plate material 50 is formed in a circular shape. The multiple small holes 52 opened in the plate material 50 are formed in an area excluding the central portion 51 of the flat plate. The multiple small holes 52 can be formed in an annular shape, and in a disk-shaped plate material 50, the multiple small holes 52 are preferably formed in an annular shape. The multiple small holes 52 may also be formed in a concentric pattern in the circular plate material 50. Preferably, the plate material 50 has a metal mesh structure, and multiple small holes 52 are opened. As the metal constituting the plate material 50, a material with a high heat capacity, such as aluminum, SUS, copper, or nickel, can be suitably used.

[0043] On the other hand, it is preferable that the gas exhaust hole 13 opened in the top surface 14 of the exterior case 10 is positioned so that it overlaps with the center portion 51 of the plate material 50 in a plan view. By positioning the gas exhaust hole 13 in an area where no small holes 52 are formed, the gas exhaust hole 13 and the small holes 52 do not overlap, preventing the gas that has passed through the multiple small holes 52 from being directly released outside the exterior case 10, and allowing the gas to be released from the power supply unit 100 in a state where the pressure and temperature have been further reduced, thereby improving safety.

[0044] Furthermore, the total opening area of ​​the plate material 50, which is the sum of the opening areas of the multiple small holes 52, is preferably larger than the opening area when the safety valve 1a is open. With this configuration, even when the safety valve 1a of any one secondary battery cell 1 is opened, an opening area of ​​at least the same size is ensured, which theoretically prevents an increase in pressure inside the power supply device 100 and reduces the risk of rupture due to an increase in internal pressure. Furthermore, by forming small holes 52 rather than simply forming an opening the same size as the safety valve 1a, it is possible to prevent high-pressure gas from being released all at once, and by distributing the gas among multiple small holes 52, it is possible to efficiently guide the gas from the multiple small holes 52 to the gas exhaust hole 13 while reducing pressure.

[0045] The opening area of ​​each of the small holes 52 is designed to a preferred value depending on the capacity and size of the secondary battery cell 1. Preferably, the inner diameter of each small hole 52 is set to φ2 mm or less.

[0046] On the other hand, it is preferable that the opening area of ​​the gas exhaust hole 13 opened in the exterior case 10 be equal to the opening area when the safety valve 1a is open. As described above, even if the safety valve 1a of any one secondary battery cell 1 is opened, by ensuring that the same opening area is maintained in the exterior case 10, it is theoretically possible to avoid a rise in pressure inside the power supply device 100 and reduce the risk of explosion due to an increase in internal pressure. In addition, it is possible to efficiently exhaust gas that has passed through the multiple small holes 52 to the outside of the power supply device 100 through the gas exhaust hole 13.

[0047] Furthermore, it is preferable to form a flame-extinguishing duct space 55 between the plate material 50 and the top surface 14 of the outer case 10. In other words, it is preferable to form the flame-extinguishing duct space 55 between the plurality of small holes 52 and the gas exhaust hole 13. With this configuration, gas that passes through the plurality of small holes 52 in the plate material 50 can be temporarily introduced into the flame-extinguishing duct space 55 to further reduce its pressure and temperature before being exhausted from the gas exhaust hole 13 in the top surface 14 of the outer case 10. As shown in the enlarged cross-sectional view of FIG. 13 , the flame-extinguishing duct space 55 can be a narrow area, which allows for a lower height than the power supply unit 600 according to the comparative example shown in FIG. 17 . The height of the flame-extinguishing duct space 55 is, for example, 2 mm or less.

[0048] Furthermore, it is preferable that the side of the multiple secondary battery cells 1 where the safety valve 1a is provided faces the flame-extinguishing duct space 55. Furthermore, it is preferable that the power supply device 100 defines a gas exhaust path so that when gas is released from any of the multiple secondary battery cells 1 inside the outer case 10, the gas is guided in the longitudinal direction of the outer case 10, then along the inner surface of the side surface 16 to the inner surface of the top surface 14, and then guided to the gas exhaust hole 13. With this configuration, as shown in Figure 25 (described later), the high-pressure gas released from the outer can of the secondary battery cell 1 is not directly discharged through the gas exhaust path, but is first guided in the longitudinal direction inside the outer case 10, guided along the side surface 16 to the top surface 14, and then discharged from the gas exhaust hole 13. With this configuration, the pressure and temperature of the gas are reduced to a certain extent inside the outer case 10 before being discharged to the outside, thereby improving safety.

[0049] (Lead Plates 4) Lead plates 4 are arranged on the side surfaces of the battery holder 21. The lead plates 4 connect the electrodes of the end surfaces 1c of the rechargeable battery cells 1 together, connecting multiple rechargeable battery cells 1 in series or parallel. In the examples of Figures 3 and 9, the end surfaces 1c of 90 rechargeable battery cells 1 are connected together with lead plates 4, connecting the rechargeable battery cells 1 in a 9-in-10 parallel configuration. Note that the number and arrangement of rechargeable battery cells 1, and the number of series or parallel connections, are not limited to this example, and any number and arrangement can be used as appropriate. These lead plates 4 are made of a metal plate with excellent conductivity, such as a nickel plate.

[0050] (Insulating Plates 40) Insulating plates 40 are also disposed on the end surfaces of the lead plates 4. In the examples shown in Figures 6 to 8, the insulating plates 40 include a first insulating plate 40A and a second insulating plate 40B. The first insulating plate 40A is interposed between the underside of the first battery block 20A and the spacer portion 30. The second insulating plate 40B is interposed between the spacer portion 30 and the second battery block 20B. The first insulating plate 40A and the second insulating plate 40B are formed to a size sufficient to cover the entire surface of the lead plates 4 of the first battery block 20A and the second battery block 20B. Electrode windows 41 are also partially opened to expose the electrode portions of the lead plates 4. These insulating plates 40 are made of a material with excellent insulating properties, such as paper or mica.

[0051] (Circuit Board 3) Each first battery block 20A and second battery block 20B is connected to the circuit board 3 via lead plates 4. 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 for holding such a circuit board 3 may also be provided.

[0052] (Spacer 30) A spacer 30 is interposed between the first battery block 20A and the second battery block 20B. The spacer 30 extends in the longitudinal direction of the first battery block 20A and the second battery block 20B. In the example shown in Figures 6 to 8, the spacer 30 includes a partition plate 32 extending in the longitudinal direction of the first battery block 20A and the second battery block 20B, and a spacer wall 35 disposed around the partition plate 32 and extending in a direction intersecting the partition plate 32. As shown in Figures 6 to 7, the spacer wall 35 is formed slightly larger than the first battery holder 21A of the first battery block 20A and the second battery holder 21B of the second battery block 20B so as to cover a portion of the side surface of these holders. Preferably, the partition plate 32 and the spacer wall 35 are integrally molded. The spacer portion 30 is made of a material with excellent insulating properties, for example, a resin such as polycarbonate or PC-ABS alloy.

[0053] The partition plate 32 is preferably formed as a plate without any through holes penetrating the top and bottom sides, which insulates the first battery block 20A from the second battery block 20B and prevents conductive liquids such as salt water from shorting across the first ventilation channel FP1 and the second ventilation channel FP2 when the battery block 20A is submerged in water.

[0054] (First Inlet 33A; Second Inlet 33B) Between the spacer portion 30 and the first battery block 20A, a first ventilation passage FP1 is formed for flowing a first cooling airflow to cool the first battery block 20A. A second ventilation passage FP2 is formed between the spacer portion 30 and the second battery block 20B for flowing a second cooling airflow to cool the second battery block 20B. In the example shown in FIGS. 3 , 20 , and 21 , the first ventilation passage FP1 is provided on the upper surface side along the longitudinal direction of the partition plate 32, and the second ventilation passage FP2 is provided on the lower surface side. A first inlet 33A and a second inlet 33B are opened at one longitudinal end of the spacer portion 30. Examples of the first inlet 33A and the second inlet 33B are shown in the front view of the battery module 2 in FIG. 10 . As shown in this figure, the first inlet 33A is formed by cutting out the upper end of a first wall surface of the spacer wall portion 35, which is located at the longitudinal end face of the spacer portion 30. The second inlet 33B is formed by cutting out the lower end of the first wall surface. As shown in Figures 3 and 20, the first inlet 33A is connected to one end of the first ventilation passage FP1. The second inlet 33B is connected to one end of the second ventilation passage FP2.

[0055] (First Outlet 34A; Second Outlet 34B) On the other hand, a first outlet 34A and a second outlet 34B are opened at the other longitudinal end of the spacer portion 30. Examples of the first outlet 34A and the second outlet 34B are shown in the rear view of the battery module 2 in FIG. 11. As shown in FIGS. 3, 6, and 20, the first outlet 34A communicates with the other end of the first ventilation passage FP1. Furthermore, as shown in FIGS. 3, 8, 20, and 22, the second outlet 34B communicates with the other end of the second ventilation passage FP2. In this way, the first inlet 33A and the first outlet 34A are opened on the upper surface side of the partition plate 32, and the second inlet 33B and the second outlet 34B are opened on the lower surface side of the partition plate 32.

[0056] Meanwhile, the exterior case 10 has a case inlet 17 and a case outlet 18. The case inlet 17 opens on a first case surface inside the side surface 16, facing one longitudinal end of the exterior case 10. The case outlet 18 is connected to the first inlet 33A and the second inlet 33B. The case outlet 18 also opens on a second case surface inside the side surface 16, facing the other longitudinal end of the exterior case 10. As shown in FIGS. 3 and 20 , the case outlet 18 is connected to the first outlet 34A and the second outlet 34B. With this configuration, the multiple secondary battery cells 1 housed inside the exterior case 10 of the power supply device 100 can be efficiently cooled by flowing cooling air from the case inlet 17 to the case outlet 18. In particular, in power supply devices that house a large number of secondary battery cells in a storage case with limited internal space, it is not easy to cool the secondary battery cells that generate heat during charging and discharging, and heat tends to accumulate in the secondary battery cells located in the middle. If it takes a long time to cool the secondary battery cells, the amount of time the secondary battery cells cannot be used increases, reducing usage efficiency. Even in such cases, providing a path for cooling air between the battery blocks 20 has the advantage of allowing cooling air to be blown into the interior, thereby enabling efficient heat exchange.

[0057] (Third ventilation passage FP3) Furthermore, on the inner surface of the exterior case 10, a third ventilation passage FP3 is formed between the exterior case 10 and the first battery block 20A, and a fourth ventilation passage FP4 can also be formed between the exterior case 10 and the second battery block 20B. One end of the third ventilation passage FP3 is connected to the case inlet 17 and the other end is connected to the case outlet 18. Similarly, one end of the fourth ventilation passage FP4 is connected to the case inlet 17 and the other end is connected to the case outlet 18. In the examples shown in the vertical cross-sectional views of Figures 3, 20, 23, and 24, the third ventilation passage FP3 is provided between the inner surface of the top surface 14 of the exterior case 10 and the first battery block 20A, and the fourth ventilation passage FP4 is provided between the inner surface of the bottom surface 15 of the exterior case 10 and the second battery block 20B. In this way, in addition to the first ventilation passage FP1 and the second ventilation passage FP2, the third ventilation passage FP3 and the fourth ventilation passage FP4 are used to send cooling air into the interior of the outer case 10 via multiple paths, making it possible to cool the first secondary battery cell 1A and the second secondary battery cell 1B inside more efficiently.

[0058] The power supply device 100 may also be provided with a blower fan for forcibly blowing cooling air. The blower fan may be provided, for example, on the case inlet 17 side or the case outlet 18 side.

[0059] (Gas Exhaust Path) Furthermore, the first ventilation passage FP1 and the second ventilation passage FP2 can also function as gas exhaust paths for exhausting gas released when the safety valve 1a provided in each secondary battery cell 1 is open from the exterior case 10 to the outside through the gas exhaust holes 13. With this configuration, the gas exhaust path for exhausting high-temperature, high-pressure gas released in the event of an abnormality in the secondary battery cell 1 to the outside of the power supply device 100 can be used as a ventilation path for cooling air without having to be provided separately within the exterior case 10, thereby efficiently utilizing the limited space within the exterior case 10 and contributing to a simpler configuration and a lower profile.

[0060] In the example shown in the longitudinal cross-section of Figure 25, the exterior case 10 defines a gas exhaust path within itself. In the event that gas is released from one of the secondary battery cells 1, the gas exhaust path guides the gas to the gas exhaust hole 13. The gas exhaust path includes a first space 31A, a second space 31B, a third space 31C, and a fourth space 31D, each extending across the interior of the exterior case 10 along the longitudinal direction. The first space 31A forms a first ventilation passage FP1 formed between the first battery block 20A and the second battery block 20B. The second space 31B forms a second ventilation passage FP2. The third space 31C is formed between the bottom surface of the second battery block 20B and the inner surface of the bottom surface 15 of the lower case 12. The fourth space 31D is formed between the top surface of the first battery block 20A and a circuit board 3 located on the inner surface of the top surface 14 of the upper case 11. Furthermore, on the inner surface of the side surface 16 of the exterior case 10, the first space 31A, second space 31B, third space 31C, and fourth space 31D are connected to a fifth space 31E that extends to one surface in the shorter direction of the exterior case 10 (the up-down direction of the left side surface 16 in FIG. 25 ). The fifth space 31E is further connected to a sixth space 31F formed on the inner surface of the top surface 14 of the exterior case 10. The sixth space 31F extends along the longitudinal direction on the back surface of the upper case 11 to the gas exhaust hole 13. With this configuration, as shown in FIG. 25 , when high-temperature, high-pressure gas is exhausted from any of the secondary battery cells 1, it is exhausted to one of the first space 31A, second space 31B, third space 31C, or fourth space 31D depending on the exhaust position, i.e., the position of the safety valve 1a provided on the secondary battery cell 1. Gas discharged into any of the first space 31A, second space 31B, third space 31C, and fourth space 31D is guided to the sixth space 31F through the fifth space 31E, and is finally discharged to the outside of the outer case 10 through the gas discharge hole 13. Note that while this structure has been described with reference to an example in which the fifth space 31E is provided on the left side of the inner surface of the outer case 10 in Fig. 25, the present disclosure is not limited to this structure, and a separate gas discharge path may also be formed on the right side of the inner surface of the outer case.

[0061] Furthermore, it is desirable that the end faces of the rechargeable battery cells 1 constituting the first battery block 20A and the end faces of the rechargeable battery cells 1 constituting the second battery block 20B are arranged facing each other via the spacers 30. Furthermore, it is desirable that a safety valve 1a be provided on either the end face of the rechargeable battery cells 1 of the first battery block 20A or the end face of the rechargeable battery cells 1 of the second battery block 20B, which are facing each other via the spacers 30. For example, it is desirable that one of the opposing end faces of the rechargeable battery cells 1 of the first battery block 20A and the second battery block 20B is a positive electrode and the other is a negative electrode. Since a safety valve is generally provided on either the positive or negative electrode, providing a safety valve 1a on only one of the opposing electrode surfaces prevents high-temperature, high-pressure gas from escaping from both end faces, ensuring safety.

[0062] 25, the exhaust direction of gas released when the safety valve 1a of either the secondary battery cell 1 facing the first ventilation passage FP1 or the second ventilation passage FP2 is opened is designed to run from right to left. Meanwhile, the blowing direction of the cooling air, i.e., the flow direction of the first cooling air in the first ventilation passage FP1 and the flow direction of the second cooling air in the second ventilation passage FP2, is designed to run from left to right as shown in FIG. 20. In this way, the exhaust direction of gas and the blowing direction of the cooling air are designed to be opposite to each other.

[0063] Furthermore, by arranging the terminals of the battery modules 2 midway through the ventilation passage, it is possible to cool the connection terminals in addition to cooling the rechargeable battery cells 1. In the examples of Figures 10, 20, 25, etc., the first connection terminals 24A connected to the input / output of the first battery block 20A are arranged near the case inlet 17. In the examples of Figures 11 to 20, etc., the second connection terminals 24B connected to the input / output of the second battery block 20B are arranged near the case outlet 18. This also makes it possible to cool the terminals through which a large current flows and generates Joule heat. This configuration is not limited to this; the positions of the first connection terminals 24A and the second connection terminals 24B may be reversed, or both may be arranged on the case inlet 17 side or the case outlet 18 side. Furthermore, they may be arranged in any of the first space 31A, second space 31B, third space 31C, and fourth space 31D.

[0064] (Check valve) Furthermore, an openable / closable lid or a check valve may be provided at the case inlet 17 or the case outlet 18 of the outer case 10. In particular, safety can be enhanced by allowing cooling air to be taken in from the outside to the inside of the outer case 10 through the case inlet 17 as shown in Fig. 20 under normal circumstances, while preventing high-temperature, high-pressure gas from leaking from the outer case 10 through the case inlet 17 in the event of an abnormality as shown in Fig. 25. In this way, an openable / closable lid or a check valve can be used to restrict the gas flow to one direction.

[0065] 21 and 25, the partition plate 32 of the spacer part 30 defines a first ventilation passage FP1 on the side facing the first battery block 20A and a second ventilation passage FP2 on the side facing the second battery block 20B. The partition plate 32 is preferably formed so that the height of the first ventilation passage FP1 and the height of the second ventilation passage FP2 are approximately equal.

[0066] (First Protrusions 25A, Second Protrusions 25B) The first battery holder 21A has one or more first protrusions 25A on the surface facing the spacer portion 30. The second battery holder 21B also has one or more second protrusions 25B on the surface facing the spacer portion 30. In the examples shown in Figures 8, 26, and 27, the first battery holder 21A has multiple first protrusions 25A on the underside of the spacer portion 30, facing the upper surface of the partition plate 32. In the examples shown in Figures 28 and 29, the second battery holder 21B has multiple second protrusions 25B on the upper side, facing the lower surface of the partition plate 32. As shown in the enlarged cross-sectional view of Figure 21, each first protrusion 25A abuts against the upper surface of the partition plate 32, forming a first ventilation passage FP1, and each second protrusion 25B abuts against the lower surface of the partition plate 32, forming a second ventilation passage FP2. In this way, it is possible to easily form ventilation passages using the battery holder 21. As shown in Figures 26 to 29, the first protrusions 25A and second protrusions 25B are each formed in a block shape with a flat upper surface.

[0067] As shown in the enlarged cross-sectional view of Figure 21, the first protrusions 25A and the second protrusions 25B are arranged in the same straight line along a transverse direction intersecting the longitudinal direction of the outer case 10. This allows the partition plate 32 to be clamped and supported from above and below in a straight line, with multiple straight lines spaced apart and intersecting the longitudinal direction of the partition plate 32, allowing for stable support of the partition plate 32. However, as shown in the transverse cross-sectional view of Figure 30, it is preferable to alternately arrange the first protrusions 25A and the second protrusions 25B in a cross-sectional view intersecting the longitudinal direction of the outer case 10. With this configuration, the partition plate 32 is stably supported in a straight line from above and below, while the contact positions at the top and bottom are alternately offset. This makes it possible that in the unlikely event that high-pressure gas is discharged into either the first ventilation passage FP1 or the second ventilation passage FP2, the partition plate 32 is easily deformed in the direction of expanding the ventilation passage at the portion on the back side that is not being pressed, thereby enabling the high-pressure gas to be discharged smoothly.

[0068] 26 to 29, the insulating plate 40 has openings 42 for allowing the first protrusions 25A and the second protrusions 25B to pass through. The first protrusions 25A and the second protrusions 25B are formed to be approximately the same size, and the openings 42 are formed to be approximately the same as or slightly larger than the outer shapes of the first protrusions 25A and the second protrusions 25B. This allows the insulating plate 40 to use the openings 42 as guides for positioning.

[0069] In the above example, the power supply device 100 is attached to the electrical device to be driven and supplies power to the electrical device. When the remaining capacity of the power supply device 100 becomes low or when the power supply device 100 deteriorates over time, the power supply device 100 can be replaced to continue using the electrical device. However, the present disclosure 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 device. In the present disclosure, a power supply device is sufficient as long as it houses secondary battery cells in a case, and also includes power supply devices in which 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 power supply devices, but can also be applied to electrical devices that house secondary battery cells.

[0070] The power supply device according to the present disclosure can be suitably used, for example, as a power source for driving mobile objects such as electric carts, electric scooters, etc. The power supply device according to the present disclosure can also be suitably used, for example, as a power source for wireless devices or as a power source for portable electrical devices such as electric cleaners and power tools.

[0071] REFERENCE SIGNS LIST 1 Secondary battery cell 1A First secondary battery cell 1B Second secondary battery cell 1a Safety valve 1c End surface 2 Battery module 3 Circuit board 4 Lead plate 5 Label 10 Outer case 11 Upper case 12 Lower case 13 Gas exhaust hole 14 Top surface 15 Bottom surface 16 Side surface 17 Case inlet 18 Case outlet 19 Engagement member 20 Battery block 20A First battery block 20B Second battery block 21 Battery holder 21A First battery holder 21B Second battery holder 24A First connecting terminal 24B Second connecting terminal 25A First protrusion 25B Second protrusion 30 Spacer portion 31A First space 31B Second space 31C Third space 31D Fourth space 31E Fifth space 31F Sixth space 32 Partition plate 33A First inlet 33B Second inlet 34A First outlet 34B Second outlet 35 Spacer wall portion 40 Insulating plate 40A First insulating plate 40B Second insulating plate 41 Electrode window 42 Opening window 50 Plate material 51 Center portion 52 Small hole 55 Flame-extinguishing duct space 100 Power supply device 600 Power supply device 601 Second battery cell 610 Outer case 613 Gas exhaust hole 614 Top surface 655 Flame-extinguishing duct space 660 Cushioning material 661 Metal mesh 662 Metal plate 664 Partition wall FP1 First ventilation passage FP2 Second ventilation passage FP3 Third ventilation passage FP4 Fourth ventilation passage

Claims

1. A power supply device comprising: a plurality of secondary battery cells, each having an end face; and an exterior case housing the plurality of secondary battery cells, wherein the exterior case has a gas exhaust hole opened on part of its surface, and within the exterior case, a metal plate is positioned overlapping the gas exhaust hole, and the plate has a plurality of small holes each smaller than the end face of the secondary battery cell, and the gas exhaust hole and the small holes are formed so as not to overlap.

2. A power supply device as claimed in claim 1, wherein the plate material is formed in a flat plate shape, the plurality of small holes are formed in an annular shape in a portion of the plate excluding the central area, and the gas exhaust hole is positioned so as to overlap with the central area of ​​the plate material.

3. A power supply device as described in claim 1, wherein each of the multiple secondary battery cells has a cylindrical outer can, one side of the outer can is provided with a safety valve that opens in response to an increase in internal pressure of the outer can, and the total opening area of ​​the multiple small holes is made larger than the opening area of ​​the safety valve when it is open.

4. A power supply device according to claim 3, wherein the equivalent diameter of the entirety of said plurality of small holes is set to be equal to the equivalent diameter when said safety valve is opened.

5. A power supply device as claimed in claim 1, wherein the exterior case is formed in a box shape extending in one direction and comprises a top surface, a bottom surface spaced from the top surface, and a side surface connecting the top surface and the bottom surface, the gas exhaust hole being opened in the top surface, and a gas exhaust path is defined which, when gas is released from any of the plurality of secondary battery cells inside the exterior case, guides the gas in the longitudinal direction of the exterior case and is further guided along the inner surface of the side surface to the inner surface of the top surface, thereby guiding the gas to the gas exhaust hole.

6. A power supply device according to claim 5, wherein the gas exhaust hole is provided at the middle of the top surface.

7. A power supply device according to claim 1, wherein the opening area of ​​each of said plurality of small holes is set to φ2 mm or less.

8. A power supply device according to claim 3, wherein a flame-extinguishing duct space is formed between said plurality of small holes and said gas exhaust hole.

9. A power supply device according to claim 8, wherein the plurality of secondary battery cells are arranged in an orientation such that the side on which the safety valve is provided faces the flame-extinguishing duct space.

10. A power supply device according to any one of claims 1 to 9, further comprising a label attached to cover the gas exhaust hole of the exterior case.

11. A power supply device according to any one of claims 1 to 9, wherein the plate material is formed in a circular shape, and the plurality of small holes are formed in a concentric pattern on the circular plate material.

12. A power supply device according to any one of claims 1 to 9, wherein the plate material has a metal mesh structure.

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