Power supply device

Abstract

This power supply device comprises: a plurality of secondary battery cells each provided with a cell discharge mechanism that is opened in response to an increase in internal pressure; an exterior case which houses the plurality of secondary battery cells and in which a gas discharge port for discharging gas, discharged from the cell discharge mechanisms to the outside, is partially open; a thermally conductive metal plate that defines, inside the exterior case, a gas discharge path for guiding, to the gas discharge port, the gas discharged when any of the cell discharge mechanisms of the plurality of secondary battery cells is opened; and a heater that is thermally coupled to the metal plate.

Description

power supply

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

[0002] Power supply devices that use multiple rechargeable secondary battery cells, such as lithium-ion secondary batteries, connected in series or parallel to drive electrical devices are currently in use. It is known that the performance of lithium-ion batteries used in such power supply devices deteriorates when used at low temperatures. Therefore, power supply devices equipped with a heating mechanism for regulating the temperature of the secondary battery cells have been proposed (see, for example, Patent Document 1). The power supply device disclosed in Patent Document 1 includes a heat plate that is thermally coupled to the sidewalls and bottom ends of each secondary battery cell. This heat plate is configured to allow a thermal fluid to flow through its internal space, thereby heating the secondary battery cells.

[0003] However, the method of Patent Document 1 requires a mechanism for circulating the thermal fluid, which leads to the problem of an increased size of the power supply device. Furthermore, when using a liquid as the thermal fluid, waterproofing and leakage prevention measures are also required to prevent the liquid from entering the secondary battery cells. In particular, there has been a recent demand for improving the energy density per volume of power supply devices. To achieve this, it is necessary to miniaturize components other than the secondary battery cells as much as possible, which contradicts the demand for controlling the operating environment temperature.

[0004] International Publication No. 2020 / 146419

[0005] One object of the present disclosure is to provide a power supply device that enables secondary battery cells to be used even in low-temperature environments. Another object 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 includes a plurality of secondary battery cells, each having a cell discharge mechanism that opens in response to an increase in internal pressure; an outer case that houses the plurality of secondary battery cells and has a gas discharge port that opens in a portion of the outer case for discharging gas released from the cell discharge mechanism to the outside; a thermally conductive metal plate that defines a gas discharge path inside the outer case that guides gas released when the cell discharge mechanism of any of the plurality of secondary battery cells is opened to the gas discharge port; and a heater thermally coupled to the metal plate.

[0007] According to one embodiment of the power supply device of the present disclosure, a metal plate that defines a gas exhaust path is thermally coupled to a heater, making it possible to heat multiple secondary battery cells, and the secondary battery cells can be used stably without degrading their characteristics, especially in cold and warm environments.

[0008] FIG. 1 is a perspective view of a power supply device according to a first embodiment. FIG. 2 is a perspective view of the power supply device of FIG. 1, viewed obliquely from below on the rear side. FIG. 3 is an exploded perspective view of the power supply device of FIG. 1. FIG. 4 is an exploded perspective view of the power supply device of FIG. 2. FIG. 5 is a further exploded perspective view of the power supply device of FIG. 3. FIG. 6 is a further exploded perspective view of the power supply device of FIG. 4. FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 1. FIG. 8 is an image diagram showing a simulation result of a power supply device according to a modified example, heated by a heater. FIG. 9 is an exploded perspective view of a power supply device according to a second embodiment. FIG. 10 is an exploded perspective view of the power supply device of FIG. 9, viewed obliquely from below on the rear side. FIG. 11 is an enlarged cross-sectional view of the power supply device according to the second embodiment. FIG. 12 is an image diagram showing a simulation result of a power supply device according to the second embodiment, heated by a heater.

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

[0010] In the power supply device according to another aspect of the present disclosure, in the above-described aspect, the metal plate is spaced apart from the plurality of secondary battery cells. With this configuration, by providing a distance between the plurality of secondary battery cells and the heater, heating is performed via air, thereby making it possible to prevent rapid heating.

[0011] In addition, in the power supply device according to another aspect of the present disclosure, in any of the above aspects, the heater thermally coupled to the metal plate heats the plurality of secondary battery cells by thermal radiation without contact. With the above configuration, the plurality of secondary battery cells can be heated without contact using the metal plate spaced apart from the plurality of secondary battery cells.

[0012] Furthermore, in the power supply device according to another aspect of the present disclosure, in any of the above aspects, the metal plate is arranged in a position facing the end faces of the plurality of secondary battery cells on which the cell ejection mechanisms are provided.

[0013] The power supply device according to still another aspect of the present disclosure is the power supply device according to any one of the above aspects, wherein the heater is formed in a sheet shape.

[0014] Furthermore, in the power supply device according to another aspect of the present disclosure, in any one of the above aspects, the heater is any one of a PTC heater, an aluminum etching heater, and an electric heating wire heater.

[0015] Furthermore, in a power supply device according to another aspect of the present disclosure, in any of the above aspects, the metal plate and heater are held inside the outer case in a position aligned with the direction of gravity on the side of the plurality of secondary battery cells.

[0016] Furthermore, in the power supply device according to another aspect of the present disclosure, in addition to any of the above aspects, the heater is formed to have an area smaller than that of the metal plate.

[0017] In addition, in the power supply device according to another aspect of the present disclosure, in any of the above aspects, the edge of the metal plate is bent into an L-shape in cross section. With this configuration, the multiple secondary battery cells are heated from at least two sides, which provides the advantage of more efficient heating.

[0018] 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.

[0019] The power supply device of the present disclosure can be used as a backup power source for servers in stationary power storage applications, or as a power supply device for home, office, or factory use, as a power source for portable electrical equipment such as radios, electric cleaners, and power tools, as a driving power source for mobile objects such as electric carts, electric scooters, and assisted bicycles, and as a driving power source for vehicles such as hybrid cars and electric automobiles. Below, a power supply device used as a driving power source for power storage will be described as one embodiment of the present invention.

[0020] [Embodiment 1] A power supply device 100 according to Embodiment 1 of the present disclosure is shown in Figures 1 to 7. In these figures, Figure 1 is a perspective view of 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 diagonally below the rear side, Figure 3 is an exploded perspective view of the power supply device 100 of Figure 1, Figure 4 is an exploded perspective view of the power supply device 100 of Figure 2, Figure 5 is a further exploded perspective view of the power supply device 100 of Figure 3, Figure 6 is a further exploded perspective view of the power supply device 100 of Figure 4, and Figure 7 is a cross-sectional view taken along line VII-VII in Figure 1. The power supply device 100 shown in these figures includes an outer case 10, a battery module 2, a metal plate 20, a heater 30, and a circuit board 3.

[0021] (External Case 10) The external case 10 houses the battery module 2, metal plate 20, heater 30, circuit board 3, etc. 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 and 2, the external shape of the external case 10 is a box shape that extends in one direction.

[0022] As shown in Figures 3 to 6, the exterior case 10 is divided into three parts: a first case 11, a second case 12, and a third case 13. However, the exterior case is not limited to this configuration, and may be divided into two parts, for example, an upper case and a lower case, or may be divided into four or more parts. The exterior case 10 is made of a material with excellent strength and heat dissipation properties, such as a metal member such as a galvanized steel plate or a stainless steel plate. It may also be made of a material with excellent insulation properties, such as a resin such as polycarbonate or PC-ABS alloy.

[0023] As shown in Figures 3 to 7, an internal space is provided inside the exterior case 10 to house the battery module 2 and other components. The exterior case 10 may be arranged vertically so that the metal plate 20 and heater 30 housed in the internal space are positioned on the side surfaces of the multiple secondary battery cells 1. In other words, the metal plate 20 and heater 30 are held in an orientation that is aligned with the direction of gravity Dg on the side surfaces of the multiple secondary battery cells 1 inside the exterior case 10. As will be described later, by arranging the exterior case 10 vertically, it is expected that the temperature distribution will become more uniform due to the effects of heated air convection and the like.

[0024] (Battery Module 2) The battery module 2, also called a core pack, houses multiple rechargeable battery cells 1. The battery module 2 may also be composed of multiple battery blocks, each housing multiple rechargeable battery cells. In the examples shown in Figures 4, 6 to 7, etc., multiple cylindrical rechargeable battery cells are housed and held horizontally in the battery holder 5.

[0025] The multiple secondary battery cells 1 are connected in series or in parallel via lead plates. The number of series connections or parallel connections can be set as desired according to the required specifications. In the example shown in Figure 4, a total of 280 secondary battery cells 1 are used in the entire battery module 2, forming a 20 series x 14 parallel connection, but the present invention is not limited to this configuration.

[0026] The battery holder 5 has multiple storage cylinders that individually store the rechargeable battery cells 1. For example, as shown in Figure 7, each battery holder 5 is divided into two, an upper part and an lower part, and the two storage cylinders hold the rechargeable battery cells 1 from above and below. Such battery holders 5 can be made of resin such as polycarbonate, which has excellent insulating properties.

[0027] (Secondary battery cells 1) Each secondary battery cell 1 may be a secondary battery cell with a cylindrical or rectangular outer shape. In the examples shown in Figures 4, 6, 7, etc., cylindrical secondary battery cells 1 are arranged horizontally in a staggered pattern. Note that the number and arrangement of secondary battery cells 1 are not limited to this example, and any number and arrangement can be used as appropriate. For example, cylindrical secondary battery cells may be arranged in a matrix.

[0028] Each secondary battery cell 1 has a positive and negative electrode. The secondary battery cell 1 may be a known secondary battery such as a lithium ion secondary battery, a nickel-metal hydride battery, or a nickel-cadmium battery.

[0029] (Cell ejection mechanism 1a) As shown in Fig. 7, the exterior can of each secondary battery cell 1 is provided with a cell ejection mechanism 1a. The cell ejection mechanism 1a opens in response to an increase in the internal pressure of the exterior can, releasing gas inside the exterior can to the outside. Such a cell ejection mechanism 1a is provided, for example, on the positive electrode side of the secondary battery cell 1.

[0030] (Gas exhaust port 15) Meanwhile, the exterior case 10 is provided with a gas exhaust port 15 for releasing high-pressure gas to the outside when the cell exhaust mechanism 1a of the secondary battery cell 1 is opened and the gas is discharged. As shown in Fig. 1, in the power supply device 100 according to the first embodiment, the gap between the first case 11 and the second case 12 that constitute the exterior case 10, or the gap between the first case 11 and the third case 13, etc., serves as the gas exhaust port 15. Although not shown, an opening may be formed in the exterior case as the gas exhaust port.

[0031] (Insulating Plates 6) In addition, insulating plates 6 are arranged on the end faces of the battery modules 2. The insulating plates 6 are formed to a size that covers the entire surface of the battery modules 2. In the examples of Figures 3 to 6, etc., four insulating sheets are arranged as the insulating plates 6 between the side of the battery module 2, the right side in the figures, and the inner surface of the exterior case 10. The insulating plates 6 are made of a material with excellent insulating properties, such as paper or mica.

[0032] (Circuit Board 3) The battery module 2 is connected to the circuit board 3 via lead plates. The circuit board 3 is equipped with a charge / discharge circuit that charges and discharges the secondary battery cells 1, a protection circuit that monitors the voltage and temperature of the secondary battery cells 1 and cuts off the current in the event of an abnormality, and other such circuits. The circuit board 3 is made of a glass epoxy board or the like. The circuit board 3 is held by a board holder 4. In the example shown in Figures 3 to 6, the board holder 4 is disposed on an end surface of the battery module 2 in the thickness direction. The board holder 4 is covered by a third case 13. The third case 13 is connected to a connector or the like on the circuit board 3 and has external connection terminals.

[0033] (Metal Plate 20) The metal plate 20 defines a gas exhaust path inside the exterior case 10 that guides gas released when the cell exhaust mechanism 1a of any of the multiple secondary battery cells 1 is opened to the gas exhaust port 15. The gas exhaust path is formed on the side of the battery module 2. In the example of FIG. 7 , the gas exhaust path is formed between the left side of the battery module 2 and the inner surface of the exterior case 10. Therefore, each secondary battery cell 1 that constitutes the battery module 2 is held in a position where the end face on which the cell exhaust mechanism 1a is provided faces left in the figure. The gas exhaust path defined by the metal plate 20 forms, for example, a gas duct.

[0034] 3 to 6 is formed to have a size and shape approximately equal to that of the end face of the battery module 2. The metal plate 20 is also configured to have enough strength to withstand high-temperature, high-pressure gas when it is released from the cell ejection mechanism 1a. Such a metal plate 20 is made of a metal with excellent thermal conductivity, such as a galvanized steel plate or a stainless steel plate.

[0035] (Heater 30) The heater 30 is thermally coupled to the metal plate 20 to heat the metal plate 20. When the heater 30 is operated, the metal plate 20, which is thermally coupled to the heater 30, is heated, and the metal plate 20 heats the battery module 2. It is known that the characteristics of lithium-ion batteries, in particular, deteriorate when used at low temperatures. Therefore, depending on the ambient temperature of the environment in which the power supply device 100 is used, the heater 30 can be operated in a low-temperature environment to heat the secondary battery cells 1 and suppress the deterioration of the characteristics. In particular, by utilizing the metal plate 20 that defines the gas exhaust path, it becomes possible to heat multiple secondary battery cells 1 by thermally coupling with the heater 30, which has the advantage of simplifying the mechanism for heating the secondary battery cells 1.

[0036] The heater 30 is formed in a sheet shape. By using a thin, planar heater 30, it is possible to avoid an increase in the size of the power supply device 100. As such a planar heater 30, a PTC heater, an aluminum etching heater, an electric heating wire heater, or the like can be used.

[0037] As shown in Figure 7, the metal plate 20 thermally coupled to the heater 30 is spaced apart from the end faces of each secondary battery cell 1. In this way, heating the multiple secondary battery cells 1 through an air layer without direct contact between the heater 30 and the metal plate 20 makes it possible to prevent rapid heating. Furthermore, the heater 30 heats each secondary battery cell 1 with radiant heat, making it possible to heat the secondary battery cells 1 without contacting them.

[0038] Furthermore, the metal plate 20 can also function as a heat spreader to heat each secondary battery cell 1 evenly. Generally, when a large number of secondary battery cells are heated from the periphery, it is difficult to heat the secondary battery cells located inside. Therefore, in the power supply device 100 according to this embodiment, the end faces of the multiple secondary battery cells 1 are arranged on the same plane, and each end face is positioned facing the metal plate 20, so that each secondary battery cell 1 can be heated by the metal plate 20. In addition, the flat metal plate 20 equalizes the heat from the heater 30 in the surface direction, thereby heating the secondary battery cells evenly regardless of their position, and reducing temperature differences between the secondary battery cells.

[0039] An insulating sheet may be interposed between the heater 30 and the metal plate 20, which are thermally coupled. The insulating sheet is preferably thermally conductive so as not to impede the thermal coupling between the heater 30 and the metal plate 20. Such an insulating sheet is made of an insulating material such as silicone resin, mica, or paper. By interposing the insulating sheet, the heater 30, which is made of a conductive material such as metal, and the metal plate 20 are insulated from each other, thereby improving safety.

[0040] Furthermore, an insulating material may be interposed between the heater and the inner surface of the outer case to insulate them. For insulating the heater 30 from the outer case, materials with heat insulating properties such as mica, insulating paper, or polycarbonate (PC) sheet are preferred. Alternatively, an air gap may be provided instead of an insulating material. By providing an air gap between the heater and the inner surface of the outer case, an air layer can be formed to provide insulation and heat insulation. In particular, if the pressure resistance between the heater and the inner surface of the outer case is sufficient, an insulating plate can be eliminated, resulting in a simpler configuration, lighter weight, and lower costs.

[0041] The heater may be formed as a single piece, or multiple heater pieces may be arranged on the metal plate to cover it. The heater 30 shown in FIGS. 3 to 6 is formed to be approximately the same size and shape as the metal plate 20. However, the size of the heater 30 does not necessarily need to be the same as the metal plate 20, and it may have a smaller area than the metal plate. In particular, when the exterior case 10 is placed vertically, as shown in FIG. 7, etc., thermal convection occurs, making the upper side more likely to be heated. Therefore, the height of the heater 30 may be lower than the metal plate 20, and the bottom edges of the heater 30 and the metal plate 20 may be roughly aligned, leaving an exposed area above the metal plate 20 that is not covered by the heater 30. Here, FIG. 8 shows the results of a simulation of a power supply unit 100' according to a modified example being heated by the heater 30. In this figure, the area where two heaters 30 are arranged is indicated by dashed lines. As shown in this figure, it was confirmed that even with the heater 30 placed at the bottom and leaving the top open, 280 secondary battery cells 1 could be heated almost evenly.

[0042] [Embodiment 2] In the above example, a flat metal plate 20 was used. However, the present disclosure is not limited to a flat metal plate configuration. For example, the edge of the metal plate may be bent into an L-shape in cross section. This configuration allows the battery module to be heated from at least two sides, resulting in more efficient heating. Such an example is shown in FIGS. 9 to 11 as a power supply device 200 according to embodiment 2. In these figures, FIG. 9 is an exploded perspective view of the power supply device 200 according to embodiment 2, FIG. 10 is an exploded perspective view of the power supply device 200 of FIG. 9 viewed obliquely from below on the rear side, and FIG. 11 is an enlarged cross-sectional view of the power supply device 200 according to embodiment 2. In these figures, components similar to those in embodiment 1 and the like are designated by the same reference numerals and will not be described in detail.

[0043] The metal plate 20B has a bent portion 22 formed by bending the lower edge of the main surface 21. As shown in the enlarged cross-sectional view of FIG. 11 , the metal plate 20B, which has an L-shaped cross section and includes the bent portion 22, is positioned so that the bent portion 22 covers at least a portion of the lower surface of the battery module 2. This configuration allows the battery module 2 to be heated not only from the side but also from the bottom, thereby enabling efficient heating of the entire battery module 2 using thermal convection. FIG. 12 shows the results of a simulation of the power supply device 200 according to the second embodiment heated by the heater 30. As shown in this figure, the temperature of the lower secondary battery cells is higher than in FIG. 8 . The lower secondary battery cell temperature is particularly reduced, reducing the temperature difference with the middle portion, resulting in more uniform heating.

[0044] While the above examples have been described using stationary power supply devices, the present disclosure is not limited to such applications. The power supply device can also be used for other purposes, such as attaching it to an electrical device to be driven and supplying power to the electrical device. Examples of electrical devices include mobile objects such as electric vehicles and electric carts, as well as portable electrical devices. In such electrical devices, 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 device. However, the present disclosure is not limited to replaceable power supply devices that primarily 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 that houses secondary battery cells in a case is sufficient, and also includes power supply devices that incorporate secondary battery cells for driving the electrical device within the housing itself. In other words, the present disclosure is not limited to replaceable power supply devices, but can also be applied to electrical devices that incorporate secondary battery cells.

[0045] The power supply device according to the present invention can be suitably used as a backup power source for servers, etc., as a power storage device for home, office, factory, etc., or as a driving power source for mobile objects such as electric carts and electric scooters. It can also be used as a power source for radios and as a power source for portable electrical equipment such as electric cleaners and power tools.

[0046] REFERENCE SIGNS LIST 100, 100', 200 Power supply device 1 Secondary battery cell 1a Cell ejection mechanism 2 Battery module 3 Circuit board 4 Board holder 5 Battery holder 6 Insulating plate 10 Outer case 11 First case 12 Second case 13 Third case 15 Gas exhaust port 20, 20B Metal plate 21 Main surface 22 Bent piece 30 Heater

Claims

1. A power supply device comprising: a plurality of secondary battery cells, each of which is provided with a cell discharge mechanism that opens in response to an increase in internal pressure; an exterior case that houses the plurality of secondary battery cells and has a gas discharge port opened in a portion of the case for discharging gas released from the cell discharge mechanism to the outside; a thermally conductive metal plate that defines a gas discharge path inside the exterior case for guiding gas released when the cell discharge mechanism of any of the plurality of secondary battery cells is opened to the gas discharge port; and a heater thermally coupled to the metal plate.

2. A power supply device according to claim 1, wherein the metal plate is spaced apart from the plurality of secondary battery cells.

3. A power supply device according to claim 1, wherein the heater, thermally coupled to the metal plate, is configured to heat the multiple secondary battery cells by thermal radiation without contacting the cells.

4. A power supply device according to claim 1, wherein the metal plate is arranged in a position facing the end faces of the plurality of secondary battery cells on which the cell ejection mechanism is provided.

5. A power supply device according to claim 1, wherein the heater is formed in a sheet shape.

6. A power supply device according to claim 1, wherein the heater is any one of a PTC heater, an aluminum etching heater, and an electric heating wire heater.

7. A power supply device according to any one of claims 1 to 6, wherein the metal plate and heater are held inside the exterior case, on the side of the multiple secondary battery cells, in a position aligned with the direction of gravity.

8. A power supply device according to any one of claims 1 to 6, wherein the edge of the metal plate is bent into an L-shape in cross section.

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