Power supply device

Abstract

The present invention suppresses an imbalance between a temperature rise and a temperature difference in a battery cell. This power supply device comprises a battery holder 5 for positioning a plurality of battery cells 1 at fixed locations. The battery holder 5 includes: inner holders 20 for positioning the plurality of battery cells 1 at fixed locations; and an outer holder 30 for positioning the inner holders 20 at fixed locations on the inner part of the battery holder. Each inner holder 20 is a conductive metal block, and the plurality of battery cells therein are arranged in insertion holes 23 to constitute a battery block 10. The outer holder 30 insulates a plurality of battery blocks 10, which are connected in series, and positions the battery blocks at fixed locations by way of insulating walls 33. Each inner holder 20 is connected to one electrode of the corresponding battery cells 1 and is arranged in a thermal coupling state in surface contact with an outer peripheral surface 1a of the battery cells 1. The inner holder 20 is used, in combination with a connection line connecting the battery cells 1 in parallel and a connection line connecting adjacent battery blocks 10 in series, for dispersing heat from the battery cells 1.

Description

power supply

[0001] The present disclosure relates to a power supply device including a plurality of battery cells.

[0002] Power supply devices are used for applications in which multiple rechargeable battery cells, such as lithium-ion secondary batteries, are connected in series or parallel and housed in an exterior case to drive electric vehicles such as civil engineering and construction equipment and vehicles, or electric equipment such as power tools (see, for example, Patent Document 1). The battery cells used in such power supply devices generate heat due to Joule heat generated by charging and discharging current, and therefore must be cooled to suppress temperature increases. In particular, in recent years, there has been a demand for power supply devices with higher output and capacity, and as a result of the progress made in increasing the capacity of the battery cells used, the amount of heat generated also tends to increase.

[0003] As a countermeasure against such heat, as shown in Figure 8, a cooling plate 840 for flowing a medium such as cooling air may be placed on the side of a battery block 830 made up of multiple battery cells 801, and heat exchange may be performed by bringing the cooling plate 840 into contact with the battery cells 801 arranged at the end.

[0004] However, in a configuration in which multiple battery cells 801, particularly cylindrical batteries, are stacked, they are often arranged in a staggered pattern with rows offset from each other, as shown in Figure 8, for space efficiency reasons. As a result, the battery cells 801 located at the end of the battery block 830 alternate between being in contact with the cooling plate 840 installed on the side of the battery block 830 and not being in contact with it. Furthermore, even for battery cells 801 that are in contact with the cooling plate 840, if the battery cells 801 are cylindrical, the contact points are line contact, and the contact area is small. This makes it difficult to achieve efficient heat exchange.

[0005] JP 2018-060594 A

[0006] One object of one embodiment of the present disclosure is to provide a power supply device capable of efficiently cooling multiple battery cells. Another object is to provide a power supply device that efficiently exchanges heat among multiple battery cells and reduces imbalances in temperature differences. Yet another object is to provide a power supply device that can connect battery cells in parallel or series to reduce electrical resistance in connection lines through which load current flows, thereby reducing unnecessary power loss and heat energy generated by charging and discharging currents. 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, other problems can be extracted from the description of the specification, drawings, and claims of the present disclosure.

[0007] A power supply device according to one embodiment of the present disclosure includes all of the following configurations (a) to (h): (a) The power supply device includes a battery holder that arranges multiple battery cells in fixed positions. (b) The battery cells have positive and negative electrodes. (c) The battery holder includes an inner holder and an outer holder that arranges the inner holder in a fixed position inside. (d) The inner holder is a conductive metal block with insertion holes that arrange the battery cells in fixed positions, and multiple battery cells are arranged in the insertion holes of the metal block to form a battery block. (e) The battery block aligns the electrodes of the multiple battery cells in the same direction, electrically connecting the multiple battery cells in parallel. (f) The outer holder is an insulating resin block with an internal space that arranges the battery blocks in fixed positions. (g) The resin block outer holder is integrally formed with an insulating partition wall that is arranged between adjacent battery blocks with a potential difference. (h) The inner holder is electrically connected to one of the positive and negative electrodes of the battery cell guided in the insertion hole, and forms part of the connection line that connects adjacent battery blocks in series.

[0008] The above configuration has the advantage of being able to efficiently cool multiple battery cells. It also has the advantage of being able to efficiently exchange heat between multiple battery cells and reduce imbalances in temperature differences. By connecting battery cells in parallel or series, it is possible to reduce the electrical resistance of the connection lines through which the load current of the power supply device flows, thereby reducing unnecessary power loss and heat energy generated by charge and discharge currents.

[0009] FIG. 1 is a schematic perspective view showing a power supply device according to a first embodiment. FIG. 2 is a schematic vertical cross-sectional view of the power supply device taken along II-II in FIG. 1. FIG. 3 is an enlarged cross-sectional perspective view of a main portion of the power supply device. FIG. 4 is a schematic exploded perspective view of the power supply device of FIG. 1. FIG. 5 is a schematic horizontal cross-sectional view of the power supply device taken along V-V in FIG. 1. FIG. 6 is an enlarged schematic cross-sectional view showing a state in which battery cells are connected via lead plates. FIG. 7 is an enlarged schematic cross-sectional view showing a state in which they are connected by laser welding and soldering. FIG. 8 is a schematic view of a conventional power supply device.

[0010] The embodiments of the present disclosure may be specified by the following configurations and features. A power supply device according to one embodiment of the present disclosure has all of the following configurations (a) to (h): (a) The power supply device includes a battery holder in which multiple battery cells are arranged in fixed positions. (b) The battery cells have positive and negative electrodes. (c) The battery holder includes an inner holder and an outer holder in which the inner holder is arranged in a fixed position. (d) The inner holder is a conductive metal block with insertion holes in which the battery cells are arranged in fixed positions, and multiple battery cells are arranged in the insertion holes of the metal block to form a battery block. (e) The battery block aligns the electrodes of the multiple battery cells in the same direction, electrically connecting the multiple battery cells in parallel. (f) The outer holder is an insulating resin block with an internal space in which the battery blocks are arranged in fixed positions. (g) The resin block outer holder is integrally formed with an insulating partition wall arranged between adjacent battery blocks with a potential difference. (h) The inner holder is electrically connected to one of the positive and negative electrodes of the battery cell guided in the insertion hole, and forms part of the connection line that connects adjacent battery blocks in series.

[0011] The power supply device described above has the advantage that battery cells inserted into the insertion holes of the inner holder of the metal block are arranged in good contact, and the battery cells are positioned in the inner holder with favorable thermal coupling, thereby efficiently cooling the battery cells and suppressing temperature rise. Furthermore, the power supply device described above has multiple insertion holes in one inner holder, and battery cells are inserted into each insertion hole, and each battery cell is arranged in favorable thermal coupling with the inner holder. This also has the advantage of suppressing imbalances in temperature rise among battery cells that generate heat due to Joule heat, thereby suppressing deterioration of specific battery cells. Furthermore, the power supply device described above has the advantage that the inner holder serves as a connection line connecting multiple battery cells in parallel and also forms part of the connection line connecting adjacent battery blocks in series, thereby reducing electrical resistance in the connection line and minimizing power loss and heat energy due to Joule heat. The inner holder connects multiple battery cells that make up the battery block in parallel and is used as a connection line connecting battery blocks each consisting of multiple parallel-connected battery cells in series, so the connection line is a metal block, thereby reducing electrical contact resistance. The electrical resistance of the connection lines can be reduced because the cross-sectional area of ​​the current-carrying path of metal block connection lines can be made larger than that of the metal bus bars used in ordinary power supplies. Power supplies that can reduce the electrical resistance of their connection lines not only reduce the heat energy generated by Joule heat and the temperature rise of the battery cells, but also reduce the power loss that occurs in proportion to the product of the square of the load current and the electrical resistance, and also reduce the voltage drop that increases in proportion to the product of the electrical resistance and the load current.

[0012] In a power supply device according to another embodiment of the present disclosure, in the above-described aspect, the battery cells are configured such that the opening of an outer can, which has one end closed, is closed with a sealing plate, and the positive and negative electrodes of the battery cells include outer can electrodes provided on the outer can and sealing plate electrodes provided on the sealing plate. The above-described power supply device has the advantage of being able to efficiently cool multiple battery cells having outer can electrodes and sealing plate electrodes, and of being able to efficiently exchange heat among the multiple battery cells and reduce temperature imbalances. Furthermore, by connecting the battery cells in parallel or in series, the electrical resistance of the connection lines through which the load current of the power supply device flows can be reduced, thereby reducing unnecessary power loss and heat energy generated by charging and discharging currents.

[0013] A power supply device according to another embodiment of the present disclosure can be configured in any of the above-described configurations such that the outer surface of the battery cell's exterior can directly contacts the inner surface of the insertion hole of the inner holder without an insulating layer therebetween, and the battery cell's exterior can electrode is electrically connected to the metal block of the inner holder. This power supply device has the advantage of increasing the contact area between the battery cell's exterior can electrode and the inner surface (inner circumferential surface) of the insertion hole provided in the metal block of the inner holder, thereby enabling the battery cell and inner holder to be electrically connected with lower resistance.

[0014] In a power supply device according to another embodiment of the present disclosure, in any of the above aspects, the battery cells may be configured such that the outer periphery of the outer can is covered with an insulating film, and the end face of the outer can is electrically connected to the inner holder via a lead plate. This power supply device has the advantage that the battery cells and the metal block of the inner holder are electrically connected via the lead plate, thereby enabling a more reliable and stable electrical connection between the battery cells and the inner holder.

[0015] In a power supply device according to another embodiment of the present disclosure, in any of the above aspects, the outer periphery of the end face of the outer can may be soldered or laser welded to the inner periphery of the insertion hole of the inner holder. The above power supply device electrically connects the battery cell and inner holder by soldering or laser welding at the boundary area where they approach each other, which has the advantage of enabling a more reliable and stable electrical connection between the battery cell and inner holder. The outer periphery of the end face of the outer can refers to the portion along the periphery of the end face of the outer can, near the outer periphery.

[0016] In a power supply device according to another embodiment of the present disclosure, in any of the above aspects, the inner holder can be made of a metal including aluminum, an aluminum alloy, copper, or a copper alloy. The above power supply device has the advantage that the metal inner holder, which has excellent electrical and thermal conductivity, can efficiently cool the multiple battery cells and can efficiently exchange heat between the multiple battery cells, thereby reducing temperature imbalances. Furthermore, the above configuration has the advantage that the inner holder, which contacts the battery cell surface over a wide area, also serves as a metal block with excellent thermal and electrical conductivity in the connection lines, thereby reducing the electrical resistance of the connection lines through which the load current flows, thereby reducing unnecessary power loss and heat energy generated by charging and discharging currents.

[0017] In a power supply device according to another embodiment of the present disclosure, in any of the above aspects, the electrodes of the battery cells constituting the battery block are connected in parallel via parallel lead plates, and the battery blocks arranged adjacent to the outer holder can be connected in series via bus bars that connect the inner holder and the electrodes of the battery cells.

[0018] In the above power supply device, the multiple battery cells that make up the battery blocks are connected in parallel by parallel lead plates, and the inner holders are connected to the electrodes by bus bars to connect adjacent battery blocks in series. Therefore, while the multiple battery cells are connected in parallel by the inner holders, these inner holders are also used for the connection lines that connect the battery blocks in series. This reduces the electrical resistance of the connection lines that connect multiple battery cells in parallel, and also reduces the electrical resistance of the connection lines that connect adjacent battery blocks in series, thereby reducing the adverse effects of electrical resistance in the connection lines, i.e., the adverse effect of increased electrical resistance, i.e., the heat energy generated by Joule heat of the current, and further reduces power loss due to electrical resistance and the decrease in output voltage due to electrical resistance. Furthermore, the above power supply device has the advantage that a bus bar is located on one side of the battery cell electrodes, making the bottom side of the battery cell flat, and a cooling plate can be placed on this surface in a desirable thermally coupled state.

[0019] In a power supply device according to another embodiment of the present disclosure, in any of the above aspects, the inner holder can be a heat sink for the thermal energy of the battery cells that comes into surface contact with the outer circumferential surfaces of the battery cells.

[0020] The above power supply device has the advantage that battery cells are arranged in surface contact with the insertion holes of the inner holder of the metal block, positioning the battery cells in a fixed position in the inner holder with favorable thermal coupling, thereby efficiently cooling the battery cells and suppressing temperature rise. Furthermore, the above power supply device has multiple insertion holes in one inner holder, and battery cells are inserted into each insertion hole, positioning each battery cell in a more favorable thermal coupling with the inner holder. This also has the advantage of suppressing imbalances in temperature rise among battery cells that generate heat due to Joule heat and suppressing deterioration of specific battery cells. Furthermore, the above power supply device has the advantage that the inner holder serves as a connection line connecting multiple battery cells in parallel and also forms part of the connection line connecting adjacent battery blocks in series, thereby reducing electrical resistance in the connection line and minimizing power loss and heat energy generated by Joule heat. The inner holder connects multiple battery cells that make up the battery block in parallel and is used as a connection line connecting battery blocks each consisting of multiple parallel-connected battery cells in series. The connection line is made of a metal block, thereby reducing electrical contact resistance. The electrical resistance of the connection lines can be reduced because the cross-sectional area of ​​the current-carrying path of metal block connection lines can be made larger than that of the metal bus bars used in ordinary power supplies. Power supplies that can reduce the electrical resistance of their connection lines not only reduce the heat energy generated by Joule heat and the temperature rise of the battery cells, but also reduce the power loss that occurs in proportion to the product of the square of the load current and the electrical resistance, and also reduce the voltage drop that increases in proportion to the product of the electrical resistance and the load current.

[0021] In a power supply device according to another embodiment of the present disclosure, in any of the above aspects, the battery cells can be cylindrical batteries. This power supply device has the advantages of being able to efficiently cool multiple cylindrical batteries, efficiently heat exchange between the multiple cylindrical batteries, and efficiently conduct heat energy from each battery block with a potential difference to the cooling plate, thereby suppressing temperature rise in the cylindrical batteries and suppressing imbalances in temperature differences between the cylindrical batteries. By connecting multiple cylindrical batteries in parallel or series, the electrical resistance of the connection lines through which the load current of the power supply device flows can be reduced, thereby reducing unnecessary power loss and heat energy generated by charging and discharging currents.

[0022] A power supply device according to another embodiment of the present disclosure, in any of the above aspects, includes a cooling plate that is thermally coupled to the metal blocks of multiple inner holders, each of which is positioned in a fixed position by an outer holder, via an insulating layer, and that can dissipate thermal energy from the battery blocks. Because the cooling plate is positioned via an insulating layer, the power supply device described above has the advantage of efficiently conducting heat energy from each battery block, which has a potential difference, to the cooling plate, thereby suppressing temperature increases in the battery cells and suppressing imbalances in the temperature differences between the battery cells that are rising in temperature.

[0023] In a power supply device according to another embodiment of the present disclosure, in any of the above aspects, the metal block of the inner holder may have an externally exposed portion that is exposed to the outside of the outer holder, and the externally exposed portion of the battery block may be connected to the cooling plate via a contact layer. This power supply device has the advantage that the inner holder exposed to the outer holder can be connected to the cooling plate in a thermally coupled state, allowing the battery cells to be cooled more efficiently by the cooling plate via the metal block of the inner holder.

[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 in no way specifies the components set forth in the claims to the components 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. In the following description, terms indicating specific directions or positions (e.g., "upper," "lower," and other terms incorporating these terms) are used as necessary. However, the use of these terms is intended to facilitate understanding of the invention with reference to the drawings, and the meaning of these terms does not limit the technical scope of the present invention. The size and positional relationships of components shown in each drawing may be exaggerated for clarity. Furthermore, in the following description, the same names and symbols indicate identical or similar components, and detailed descriptions will be omitted as appropriate. Furthermore, each element constituting the present disclosure may be configured such that multiple elements are composed of the same material, with one material serving multiple elements, or conversely, the function of one material may be shared by multiple materials.

[0025] The power supply device of the present disclosure does not specify the load to be connected, but can be used primarily as a power source for electric equipment used outdoors, 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, and factory use, and as a driving power source for vehicles such as hybrid cars and electric cars. Hereinafter, as one embodiment of the present invention, a power supply device used as a driving power source for a tamping rammer that hardens the ground by its own weight and impact will be described. [Embodiment 1]

[0026] 1 to 5 show a power supply device 100 according to a first embodiment of the present disclosure. In these figures, FIG. 1 is a schematic perspective view showing the power supply device 100 according to the first embodiment, FIG. 2 is a schematic vertical cross-sectional view of the power supply device 100 of FIG. 1, FIG. 3 is an enlarged cross-sectional perspective view of a main portion of the power supply device 100 of FIG. 1, FIG. 4 is an exploded perspective view of the power supply device 100 of FIG. 1, and FIG. 5 is a schematic horizontal cross-sectional view of the power supply device 100 of FIG. 1. The power supply device 100 shown in these figures has multiple battery cells 1 arranged in fixed positions by a battery holder 5. The battery holder 5 includes an inner holder 20 and an outer holder 30 that arranges the inner holder 20 in fixed positions. The inner holder 20 arranges the battery cells 1 in fixed positions therein to form a battery block 10. The outer holder 30 arranges multiple battery blocks 10 in fixed positions therein. (Battery Cells 1)

[0027] The battery cell 1 is a rechargeable secondary battery with positive and negative electrodes (not shown) disposed inside a metal outer can, the opening of which is closed by a sealing plate. The battery cell 1 shown in Figure 2 and other figures is a cylindrical battery 1A. The outer can is cylindrical with a closed bottom, the opening of which is sealed with a sealing plate, and the positive and negative electrodes are disposed on the outer can and sealing plate. The positive and negative electrodes consist of an outer can electrode 2 formed on the outer surface 1a and bottom surface 1b of the outer can, and a sealing plate electrode 3 disposed on the sealing plate. One of the outer can electrode 2 and the sealing plate electrode 3 is the positive electrode and the other the negative electrode. In the battery cell 1, the outer can electrode 2 is the negative electrode and the sealing plate electrode 3 is the positive electrode, or conversely, the outer can electrode 2 is the positive electrode and the sealing plate electrode 3 is the negative electrode. The sealing plate electrode 3 is disposed insulated from the center of the sealing plate, or is disposed on the sealing plate disposed at the opening of the outer can via an insulating packing.

[0028] As shown in Figures 1 to 4, the battery cells 1 (cylindrical batteries 1A) are arranged in fixed positions in the inner holder 20 with their cylindrical outer cans in a staggered arrangement with parallel orientations. The number and arrangement of the battery cells 1 are not limited to this example, and any number and arrangement can be appropriately adopted. For example, the battery cells 1 may be arranged in a matrix. Known batteries, such as non-aqueous batteries such as lithium-ion secondary batteries and nickel-metal hydride batteries, can be used for the battery cells 1, as well as all batteries, including all-solid-state batteries to be developed in the future. While cylindrical batteries 1A are preferred for the battery cells 1, the battery cells are not limited to cylindrical batteries 1A, and batteries of other shapes, such as non-cylindrical tubular batteries, can also be used.

[0029] There are two types of battery cells 1: a surface-insulated type in which the surface of the outer can is covered with an insulating film (not shown) such as heat-shrinkable film, and a surface-exposed type in which the surface of the outer can is exposed without being covered with an insulating film. In a surface-exposed type battery cell 1, the outer surface 1a of the outer can is in direct contact with a metal inner holder 20 for electrical connection. As shown in the enlarged schematic cross-sectional view of Figure 6, in a surface-insulated type battery cell 1, the bottom surface 1b of the outer can is exposed, and the exposed portion of the bottom surface 1b can be electrically connected to the open end surface 22 of the metal block of the inner holder 20 via a lead plate 24. In a surface-exposed type battery cell 1, the outer peripheral surface 1a of the outer can can be electrically connected directly to the inner holder 20. However, this type of battery cell 1 can also be electrically connected more reliably to the outer can and inner holder 20 by laser welding or soldering the bottom surface 1b and / or outer peripheral surface 1a of the outer can to the open end surface 22 of the inner holder 20, as shown in the enlarged cross-sectional view of FIG. 7, or by electrically connecting via lead plates 24 as shown in FIG. 6.

[0030] In a battery block 10 in which multiple battery cells 1 are positioned in fixed positions using inner holders 20, the end faces of the parallel-positioned battery cells 1, particularly the bottom surface 1b of the outer can, are aligned on the same plane, as shown in the cross-sectional views of Figures 2 and 3. Furthermore, the bottom surface 1b of the outer can and the open end surface 22 of the inner holder 20 are aligned on the same plane, allowing both the bottom surface 1b of the battery cells 1 and the open end surface 22 of the inner holder 20 to be thermally coupled to the cooling plate 60 in an optimal thermal coupling state. A structure in which the bottom surface 1b of the outer can and the open end surface 22 of the inner holder 20 are aligned on the same plane provides wide surface contact with the surface of the cooling plate 60 via the insulating layer 50, thermally coupling both the battery cells 1 and the inner holder 20 to the cooling plate 60 in an ideal state, allowing the cooling plate 60 to efficiently dissipate the thermal energy of the battery cells 1 and the inner holder 20 as temperatures rise.

[0031] The power supply device 100 can increase its output voltage by connecting multiple battery blocks 10 in series. The output voltage of the battery blocks 10 housed in the outer holder 30 is set to an optimal voltage for the application by adjusting the number of battery blocks 10 connected in series. The output voltage of the power supply device 100 is the product of the number (n) of battery blocks 10 connected in series and the output voltage (V) of each battery block 10. Therefore, the output voltage of the battery blocks 10 can be maximized by connecting all battery blocks 10 housed in the outer holder 30 in series. However, the output voltage can be optimized for the application by connecting the battery blocks 10 in parallel and in series without connecting all battery blocks 10 in series. A potential difference occurs between battery blocks 10 connected in series in the inner holder 20. Battery blocks 10 with potential differences can be isolated by providing insulating partitions 33 between the battery blocks 10. As described below, the insulating partitions 33 can be integrally molded into the resin outer holder 30, which is manufactured by molding the blocks. (Inner holder 20)

[0032] The inner holder 20 is a metal block with insertion holes 23 in which multiple battery cells 1 are arranged in parallel. The battery cells 1 are positioned in fixed positions with the outer peripheral surfaces 1a of the battery cells 1 in surface contact with the inner peripheral surface of the insertion holes 23 of the inner holder 20. The inner shape of the insertion holes 23 is approximately the same as the outer shape of the battery cells 1, and more precisely, is slightly larger than the outer shape of the battery cells 1, allowing the outer peripheral surfaces 1a of the battery cells 1 to be positioned in fixed positions in surface contact with the inner peripheral surface. The metal block of the inner holder 20 is preferably made of a metal with excellent electrical and thermal conductivity, such as aluminum, aluminum alloy, copper, or copper alloy. The metal block of the inner holder 20 can be mass-produced efficiently by extrusion molding or die-cast molding. The inner holder 20 of FIG. 2 has cylindrical insertion holes 23 arranged in a bale-like manner, allowing multiple cylindrical battery cells 1 to be positioned in fixed positions with high space efficiency. The inner holder 20 is a metal block that serves three functions: a first function as a battery holder 5 that positions multiple battery cells 1 in fixed positions; a second function as a connection line that connects adjacent battery blocks 10 in series; and a third function of absorbing thermal energy from each battery cell 1 and dissipating it to the outside. In this embodiment, the inner holder 20 is also a metal block that serves a fourth function as a connection line that connects multiple battery cells 1 in the same battery block 10 that are guided into the insertion holes 23 in parallel.

[0033] To position each battery cell 1 in a fixed position without misalignment, the inner shape of the insertion hole 23 of the inner holder 20 is made slightly larger than the smallest inner shape that can accommodate the battery cell 1, i.e., the outer shape of the battery cell 1. This structure allows the outer peripheral surface 1a of the battery cell 1 to be in surface contact over a wide area with the inner peripheral surface of the insertion hole 23, enabling the battery cell 1 to be positioned in a fixed position without misalignment. Furthermore, in a structure that electrically connects the outer can electrode 2 of the battery cell 1 to the metal block of the inner holder 20, this structure has the effect of reducing contact resistance between the outer can electrode 2 of the battery cell 1 and the inner holder 20 by allowing the outer peripheral surface 1a of the battery cell 1 to be in surface contact over a wide area with the inner peripheral surface of the insertion hole 23. Furthermore, this structure improves the thermal coupling between the outer surface 1 a of the battery cell 1 and the inner surface of the insertion hole 23 of the inner holder 20, efficiently conducting the thermal energy of the battery cell 1 to the metal block of the inner holder 20 and efficiently dissipating the thermal energy of the battery cell 1, thereby realizing the advantage of reducing and suppressing the temperature rise of each battery cell 1 and the imbalance in temperature differences between multiple battery cells 1.

[0034] Reducing the contact resistance between the battery cells 1 and the inner holder 20 reduces the voltage drop due to contact resistance, suppressing a decrease in the output voltage of the power supply device 100 and improving the power efficiency of the power supply device 100. Furthermore, reducing the contact resistance also has the effect of reducing the heat energy of Joule heat due to contact resistance and suppressing the temperature rise of the battery cells 1. Reducing the imbalance between the temperature rise of each battery cell 1 and the temperature difference between the battery cells 1 is extremely important for suppressing the deterioration of the electrical characteristics of the battery cells 1 due to temperature rise and extending their lifespan, because a temperature rise in the battery cells 1 causes a deterioration of their electrical characteristics.

[0035] Furthermore, as mentioned above, the preferable surface contact between the battery cells 1 and the inner holder 20 suppresses the Joule heat energy generated by contact resistance and allows the heated battery cells 1 to be efficiently dissipated. This synergistic effect reduces the imbalance between the temperature rise of each battery cell 1 and the temperature difference between the battery cells 1, thereby suppressing the deterioration of each battery cell 1 and extending its lifespan. (Outer holder 30)

[0036] The outer holder 30 is a resin block molded from insulating plastic. The outer holder 30 is a battery block holder that positions multiple battery blocks 10 in fixed positions. The outer holder 30 is a resin block with an internal space 32 that guides and positions the battery blocks 10 in fixed positions. The outer holder 30 can be manufactured by molding a resin block made of a material with excellent insulating properties, such as polycarbonate or PC-ABS alloy. The outer holder 30 shown in the cross-sectional view of FIG. 2 has an internal space 32 that is shaped to position the battery blocks 10 in fixed positions using a fitting structure. The outer holder 30 shown in FIGS. 2 to 5 has both ends of the internal space 32 open, and the internal shape of the internal space 32 is the same as the external shape of the battery blocks 10, positioning the battery blocks 10 in fixed positions using a fitting structure.

[0037] The outer holder 30 shown in Figures 1 to 3 has insulating partition walls 33 between battery blocks 10 connected in series and having a potential difference. Internal spaces 32 are located on both sides of the insulating partition wall 33, and battery blocks 10 are inserted into the internal spaces 32 to position them in a fixed position. The shape and position of the insulating partition walls 33 and internal spaces 32 can be determined based on the external shape and position of the battery blocks 10 and the arrangement of the battery cells 1, thereby preventing the battery blocks 10 from shifting position and achieving compactness and high space efficiency. The battery block 10 shown in Figure 1 has an inner holder 20 with an outer surface that is uneven and conforms to the outer peripheral surfaces 1a of the built-in battery cells 1. Therefore, the insulating partition walls 33 of the outer holder 30 have a zigzag shape that conforms to the uneven surface of the inner holder 20. This internal space 32 has the advantage that the battery blocks 10 are inserted in the axial direction of the battery cells 1, allowing each battery block 10 to be positioned in a fixed position without shifting.

[0038] The resin block of the outer holder 30 shown in the above figures is molded integrally with an insulating partition wall 33, and internal spaces 32 are provided on both sides of the insulating partition wall 33. The insulating partition wall 33, which is integral with the outer holder 30, is molded from the insulating plastic that molds the resin block, and is an insulating insulating partition wall 33. This insulating partition wall 33 insulates and positions the battery blocks 10 on both sides in fixed positions, and is therefore placed between battery blocks 10 connected in series and having a potential difference, and can be placed on both sides of the inner holders 20, which also have a potential difference, insulating them.

[0039] The outer holder 30 shown in FIG. 1 is a resin block with an outer shape extending in the arrangement direction of the multiple battery blocks 10. The outer holder 30 is an integral resin block, and the battery blocks 10 can be inserted into the internal space 32. The outer holder 30 can also be a resin block divided into two blocks, an upper block and a lower block, into two. The upper block has an internal space 32 for accommodating the upper half of the battery block 10, and the lower block has an internal space 32 for accommodating the lower half of the battery block 10. This outer holder 30 allows the battery block 10 to be placed in the internal space 32 of the lower block, and the upper block can be connected to the lower block to place the battery block 10 in the internal space 32. The two lower blocks can be joined together with the battery block 10 positioned in the internal space 32, or can be connected by a connecting mechanism (not shown) to assemble the battery block 10. However, the present disclosure is not limited to this configuration. For example, the outer holder 30 may be divided into three or more blocks.

[0040] The outer holder 30 in Figures 4 and 5 has opening windows 34 at both ends of the internal space 32, and both ends of the battery block 10 are exposed through the opening windows 34. The outer holder 30 in Figure 5 has a first opening window 34A located at the upper end, which exposes the bottom surface 1b of each battery cell 1 and the opening end surface 22 of the inner holder 20, and a second opening window 34B located at the lower end, which exposes the sealing plate electrode 3 of the battery cell 1 and the opening end surface 22 of the inner holder 20. The bottom surfaces 1b of the battery cells 1 exposed through the first opening window 34A and the opening end surface 22 of the inner holder 20 exposed through the first opening window 34A are thermally coupled to the cooling plate 60 via an insulating layer 50. A bus bar 26 that electrically connects adjacent battery blocks 10 in series is disposed in the second opening window 34B. This bus bar 26 connects the lower opening end surface 22 of the inner holder 20 to the sealing plate electrode 3, thereby connecting adjacent battery blocks 10 in series. (Parallel connection of battery cell 1)

[0041] In the power supply device 100, the battery cells 1 of the battery blocks 10 are connected in parallel, connecting the battery blocks 10 in series. The battery blocks 10 connect the battery cells 1 in parallel by using the inner holders 20 of the metal blocks as connection lines for parallel connections. In the battery block 10 of FIG. 1 , the outer can electrodes 2 of each battery cell 1 are connected in parallel via the inner holders 20, and the sealing plate electrodes 3 of each battery cell 1 are connected by a single parallel lead plate 25, connecting all of the battery cells 1 constituting the battery block 10 in parallel. In the battery block 10 shown in the cross-sectional view of FIG. 5 , the bottom surface 1b, which is one end surface of the outer can, is located on the top surface, and the sealing plate electrode 3, which is the other end surface of the outer can, is located on the bottom surface. In the battery block 10, the bottom surfaces 1b of the outer cans of all the battery cells 1 are located on the same plane (the top surface in FIG. 5 ), and the sealing plate electrodes 3 are also located on the same plane (the bottom surface in FIG. 5 ). The battery cells 1 are connected in parallel with one another by connecting the outer can electrodes 2 to the inner holder 20 and connecting the sealing plate electrodes 3 to a single parallel lead plate 25. As described above, the outer can electrodes 2 of multiple battery cells 1 in the same battery block 10 are electrically connected to one another using the inner holder 20, but similar to the electrical connection between the sealing plate electrodes 3 of each battery cell 1, the outer can electrodes 2 of each battery cell 1 can also be connected in parallel with a single lead plate. In this case, the lead plate connecting the outer can electrodes 2 of each battery cell 1 in parallel can be located on the end face of the battery cell 1 opposite the parallel lead plate 25 that connects the sealing plate electrodes 3 of each battery cell 1.

[0042] The electrical connection between the outer can electrodes 2 of the battery cells 1 and the inner holder 20 can be made using a first connection structure in which the outer surface 1a of the outer can is electrically connected by directly contacting the inner surface of the insertion hole 23 of the inner holder 20, a second connection structure in which the bottom surface 1b of the battery cell 1 is electrically connected to the opening surface of the inner holder 20 by a lead plate 24, or a third connection structure in which the bottom surface 1b of the battery cell 1 is electrically connected to the edge of the opening of the inner holder 20 by laser welding or soldering. The outer can electrodes 2 of the battery cells 1 can be electrically connected using any of the first to third connection structures, or a more stable electrical connection can be made by using multiple connection structures.

[0043] The first connection structure electrically connects the outer surface 1a of the battery cell 1 exterior can by directly contacting the inner surface of the insertion hole 23 in a surface-to-surface manner without insulating it with an insulating film or the like. This connection structure allows electrical connection by inserting the battery cell 1 into the insertion hole 23, which has the advantages of simplifying the electrical connection and reducing contact resistance by providing electrical connection over a wide area. The second connection structure, as shown in the enlarged cross-sectional view of Figure 6, has the advantage of providing a stable electrical connection between the battery cell 1 and the inner holder 20 by laser welding or spot welding the lead plate 24 to the battery cell 1 exterior can and the metal block of the inner holder 20. The third connection structure, as shown in the enlarged cross-sectional view of Figure 7, has the advantage of providing an electrical connection between the battery cell 1 and the inner holder 20 by laser welding or soldering the boundary between the battery cell 1 and the inner holder 20, without using the lead plate 24. Furthermore, the second and third connection structures have the advantage that the battery cell 1 and inner holder 20 can be electrically connected by placing the battery cell 1, whose surface is covered with an insulating film, in the insertion hole 23.

[0044] The parallel lead-plate 25, which connects the sealing plate electrodes 3 of the battery cells 1 in parallel in a battery block 10, is a single metal plate with connections to the sealing plate electrodes 3 of all battery cells 1. Furthermore, the parallel lead-plate 25 shown in the perspective views of FIGS. 1 and 3 has a bus bar 26 that connects the battery blocks 10 in series and is constructed from a single metal plate. The bus bar 26 of the parallel lead-plate 25 is connected to the inner holder 20 of an adjacent battery block 10 to connect the battery blocks 10 in series. The parallel lead-plate 25 can be electrically connected to the sealing plate electrode 3 by methods such as laser welding or spot welding. The bus bar 26 can also be electrically connected to the open end surface 22 of the inner holder 20 of an adjacent battery block 10 by laser welding or spot welding. The power supply device 100 in FIG. 2 has an outer holder 30 that holds multiple battery blocks 10 in fixed positions, housed in an outer case 6. Although not shown, the power supply device 100 also houses necessary components such as circuit boards in the outer case 6. (Series connection of battery blocks 10)

[0045] The power supply device 100 connects adjacent battery blocks 10 in series using the inner holder 20 and bus bar 26 as connection lines. The power supply device 100, which connects adjacent battery blocks 10 in series, also connects the battery cells 1 of the adjacent battery blocks 10 in series via the bus bar 26 and inner holder 20. The inner holder 20 connects the battery cells 1 of the battery blocks 10 in parallel, but also connects the battery cells 1 of adjacent battery blocks 10 in series. Therefore, the load current of the power supply device 100 flows through the inner holder 20. Because the inner holder 20 connects multiple battery cells 1 in parallel, the load current is divided and flows among the battery cells 1 connected in parallel.

[0046] The parallel lead-plates 25 shown in the perspective views of Figures 1 and 3 are provided with bus bars 26, and the parallel lead-plates 25 and bus bars 26 are integrated into a single metal plate. This parallel lead-plate 25 structure eliminates the need to connect the bus bars 26 to the parallel lead-plates 25 by laser welding, spot welding, or other methods, and offers the advantage of ideal electrical connection between the two. Furthermore, the above structure allows the parallel lead-plates 25 to be connected to the sealing plate electrodes 3, positioning the bus bars 26 in a fixed position, and then reliably and stably connecting them to the opening end surface 22 of the inner holder 20 of an adjacent battery block 10 by laser welding or spot welding. The bus bars 26 in Figures 1 and 4 connect to the opening end surface 22 in the valley region between the cylindrical batteries 1A of adjacent battery blocks 10, effectively utilizing dead space and ensuring a connection area in the extension direction of the bus bars 26, allowing for reliably and stably connecting them by laser welding or spot welding. 1 and 4 have multiple bus bars 26 and can shunt the load current, which has the advantage of reducing the electrical resistance of the bus bars 26 that connect the battery blocks 10 in series, thereby minimizing the voltage drop caused by the bus bars 26 and the heat energy generated by Joule heat in the load current. In particular, a structure that uses the metal block of the inner holder 20 in combination with the connection line through which the load current flows has the advantage of reducing the electrical resistance of the connection line and suppressing power loss and heat generation due to the load current.

[0047] The load current and rapid charging current of the power supply device 100 cause the battery cells 1 to heat up, but this load current also causes heat generation due to the electrical resistance of the connection lines. Because heat generation in the connection lines is a heat source that raises the temperature of the battery cells 1, reducing the heat generation energy of the connection lines is extremely important. In particular, because the connection lines also heat up when the battery cells 1 heat up, reducing the heat generation energy of the connection lines is extremely important for the power supply device 100. To position the battery cells 1 in a fixed position, the power supply device 100 uses an inner holder 20, which is in surface contact with the surface of the battery cells 1 over a wide area, as a metal block with excellent thermal conductivity and electrical conductivity, in addition to the connection lines. This configuration reduces the electrical resistance of the connection lines, suppressing heat generation energy due to Joule heat, and further achieves ideal features, such as surface contact with the battery cells 1, achieving a favorable thermal coupling state and efficiently dissipating the thermal energy of the battery cells 1 to the outside. In particular, the structure in which the inner holder 20 is also used as a connection line and the busbar 26 and parallel lead plate 25 form a single metal plate to connect the battery blocks 10 in series realizes the ideal feature of connecting adjacent battery blocks 10 in series in an ideal state using the outer holder 30 to suppress temperature increases (battery cell 1 cooling structure).

[0048] The power supply unit 100 uses the inner holder 20, which holds the battery cells 1 in place, as a metal block and also as a heat sink that dissipates the thermal energy of the battery cells 1. Furthermore, the power supply unit 100 cools the inner holder 20 with a cooling plate 60, allowing the thermal energy of the battery cells 1 to be dissipated to the outside more efficiently. The cooling plate 60 is a metal plate that is forcibly cooled, for example, by circulating a cooling medium such as a coolant inside, or by providing heat dissipation fins. In the power supply unit 100 shown in Figures 4 and 5, the metal block of the inner holder 20 is connected to the cooling plate 60 via an insulating layer 50 to the externally exposed portion of the outer holder 30, and the cooling plate 60 is thermally coupled to the multiple battery blocks 10. In the power supply device 100 shown in Figure 5 , both the bottom surface 1b of the battery cell 1 and the open end surface 22 of the inner holder 20 are exposed to the outside through the upper opening window 34 (first opening window 34A). These are thermally coupled to the cooling plate 60, absorbing thermal energy from both the battery cell 1 and the inner holder 20 and dissipating it to the outside. Battery blocks 10 housed in the outer holder 30 and electrically connected in series have a potential difference across the inner holder 20. When multiple inner holders 20 with a potential difference come into contact with the cooling plate 60, excessive short-circuit current flows through the cooling plate 60. To prevent this short-circuit current, the power supply device 100 shown in the cross-sectional view of Figure 5 has an insulating layer 50 between the inner holder 20 and the cooling plate 60. The insulating layer 50 can be made of an insulating material with excellent thermal conductivity. The insulating layer 50 insulates the cooling plate 60 from the battery blocks 10 with a potential difference, preventing short-circuiting due to the cooling plate 60.

[0049] An insulating sheet 51 with excellent insulating and thermal conduction properties can be used for the insulating layer 50. The insulating sheet 51 is a sheet that can deform in the thickness direction, thermally coupling the inner holder 20 and cooling plate 60 stably over a wide contact area, allowing the thermal energy of the inner holder 20 to be efficiently conducted to the cooling plate 60. Furthermore, the insulating sheet 51, which deforms in the thickness direction, thins and deforms in the areas pressed against the parallel lead-plates 25, allowing the bottom surfaces 1b of the battery cells 1, the open end surface 22 of the inner holder 20, and the parallel lead-plates 25 to be thermally coupled to the cooling plate 60 over a wide area, allowing the thermal energy of the battery cells 1 to be efficiently conducted to the cooling plate 60.

[0050] The insulating sheet 51 can be made of a material that has excellent thermal conductivity and insulation properties and a certain degree of elasticity. Examples of such materials include acrylic, urethane, epoxy, and silicone resins. Plastic sheets filled with fillers with excellent thermal conductivity, mica, and the like, can also be used. Ceramic fillers and metal fillers can be blended into resins as fillers with excellent thermal conductivity. Furthermore, a thermally conductive paste such as silicone oil can be applied between the insulating sheet 51 and the cooling plate 60 to achieve a structure that conducts heat more efficiently.

[0051] The insulating sheet 51 can be, for example, a 1-3 mm thick, elastically deformable cushion sheet with excellent thermal conductivity. The insulating sheet 51 is sandwiched in a locally crushed state, allowing it to adhere closely to the bottom surfaces 1b of the battery cells 1, the open end surfaces 22 of the inner holders 20, and the surfaces of the parallel lead plates 25. This reduces the formation of a heat insulating layer due to gaps, and allows the battery block 10 and cooling plate 60 to adhere to each other in a favorable thermally coupled state, allowing for efficient heat dissipation from the battery cells 1.

[0052] The power supply device described above can be suitably used as a power supply device that can efficiently exchange heat among a plurality of battery cells, reduce imbalances in temperature difference, and efficiently cool the battery cells.

[0053] DESCRIPTION OF SYMBOLS 100...power supply device 1...battery cell 1A...cylindrical battery 1a...outer surface 1b...bottom surface 2...external can electrode 3...sealing plate electrode 5...battery holder 6...external case 10...battery block 20...inner holder 22...opening end surface 23...insertion hole 24...lead plate 25...parallel lead plate 26...bus bar 30...outer holder 32...internal space 33...insulating partition wall 34...opening window 34A...first opening window 34B...second opening window 50...insulating layer 51...insulating sheet 60...cooling plate 801...battery cell 830...battery block 840...cooling plate

Claims

1. A power supply device comprising all of the following configurations (a) to (h): (a) The power supply device comprises a battery holder that positions multiple battery cells in fixed positions. (b) The battery cells have positive and negative electrodes. (c) The battery holder comprises an inner holder and an outer holder that positions the inner holder in a fixed position inside. (d) The inner holder is a conductive metal block with insertion holes that position the battery cells in fixed positions, and the multiple battery cells are placed in the insertion holes of the metal block to form a battery block. (e) The battery block aligns the electrodes of the multiple battery cells in the same direction, electrically connecting the multiple battery cells in parallel. (f) The outer holder is an insulating resin block with an internal space that positions the battery blocks in fixed positions. (g) The outer holder of the resin block is integrally formed with an insulating partition wall that is positioned between adjacent battery blocks that have a potential difference. (h) The inner holder is electrically connected to one of the positive and negative electrodes of the battery cell guided in the insertion hole, and forms part of a connection line that connects adjacent battery blocks in series.

2. A power supply device as claimed in claim 1, wherein the battery cell is constructed by closing one end of an outer can and closing the opening with a sealing plate, and the positive and negative electrodes of the battery cell consist of outer can electrodes provided on the outer can and sealing plate electrodes provided on the sealing plate.

3. A power supply device as claimed in claim 2, wherein the outer surface of the outer can of the battery cell is in direct contact with the inner surface of the insertion hole of the inner holder without an insulating layer therebetween, and the outer can electrode of the battery cell is electrically connected to the metal block of the inner holder.

4. A power supply device as claimed in claim 2, wherein the battery cell is formed by covering the outer surface of the outer can with an insulating film, and the end surface of the outer can is electrically connected to the inner holder via a lead plate.

5. A power supply device according to claim 2, wherein the outer periphery of the end face of the outer casing is soldered or laser welded to the inner periphery of the insertion hole of the inner holder.

6. A power supply device according to claim 1, wherein the inner holder is made of a metal selected from the group consisting of aluminum, aluminum alloy, copper, and copper alloy.

7. A power supply device according to claim 1, wherein the electrodes of the battery cells constituting the battery block are connected in parallel via parallel lead plates, and the battery block arranged adjacent to the outer holder is connected in series via bus bars connecting the inner holder and the electrodes of the battery cells.

8. A power supply device according to claim 1, wherein the inner holder is a heat sink for the thermal energy of the battery cell that is in surface contact with the outer circumferential surface of the battery cell.

9. A power supply device according to claim 1, wherein the battery cells are cylindrical batteries.

10. A power supply device as claimed in claim 1, comprising a cooling plate arranged in a thermally coupled state via an insulating layer to the metal blocks of the inner holders arranged in fixed positions by the outer holder, and the cooling plate dissipates thermal energy from the battery blocks.

11. A power supply device according to any one of claims 1 to 10, wherein the metal block of the inner holder has an external exposed portion that is exposed to the outside of the outer holder, and the external exposed portion of the battery block is connected to a cooling plate via a contact layer.

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