Battery pack system, battery module used in said battery pack system, and coupler

Abstract

[Problem] To provide a battery pack system that makes it possible to freely change electrical specifications such as voltage in accordance with use and can be efficiently installed in various spaces, thereby making it possible to enhance the degree of standardization of battery packs, the battery pack system furthermore being exceptionally easy to maintain. [Solution] A battery module 2 has a single or a plurality of power storage units B1 that are accommodated inside a housing 20. An upper end surface 20a and a lower end surface 20b of the housing are respectively provided with terminal portions 24A and 24B serving as electrodes. A plurality of battery modules 2 are electrically connected via the terminal portions. A side surface 20c of the housing 20 is provided with a connection portion 25 for connecting two battery modules 2 to each other in a state in which the side surfaces 20c of the housings face each other.

Description

Battery pack system, battery module used in the battery pack system, and connector

[0001] The present invention relates to a battery pack system including a power storage unit.

[0002] In recent years, battery packs mounted on electric vehicles have become known (see, for example, Patent Document 1). However, the required electrical specifications, such as required voltage, of electric vehicles vary depending on the model and manufacturer. The required electrical specifications, such as required voltage, of electrically powered devices other than electric vehicles also vary. Therefore, it is difficult to standardize battery packs, which causes costs to increase.

[0003] Furthermore, conventional battery packs for electrically powered devices have been basically rectangular parallelepiped-shaped battery packs arranged vertically and horizontally, and the space within the electrically powered device in which these battery packs are installed is also basically rectangular. The capacity of this space limits the electrical specifications that can be installed, and the specifications of the battery pack must be optimized for each application and space. For these reasons as well, it has been difficult to standardize battery packs.

[0004] In addition, the battery packs are arranged vertically and horizontally and firmly secured with belts or other fasteners to prevent them from interfering with each other even when subjected to vibrations, etc. However, there was also the issue of a lack of maintenance capabilities, such as inspection and replacement, when some of the battery packs malfunction.

[0005] Patent Publication No. 2022-115495

[0006] In view of the above-mentioned situation, the present invention aims to solve the problem of providing a battery pack system that allows electrical specifications such as voltage to be freely changed to suit the application, and that can be efficiently arranged in various spaces, thereby increasing the degree of standardization of battery packs and also providing excellent maintainability.

[0007] That is, the present invention encompasses the following inventions: (1) A battery pack system formed by connecting a plurality of battery modules, wherein the battery module has one or more power storage units housed inside a housing, has terminal units serving as electrodes on the upper and lower end faces of the housing, the plurality of battery modules are electrically connected via the terminal units, and has a connecting unit provided on a side face of the housing for connecting two of the battery modules with the side faces of the housing facing each other.

[0008] According to this configuration, the storage units of the multiple battery modules are connected, and electrical specifications such as output voltage can be changed by increasing or decreasing the number of battery modules according to the voltage required for each electrically powered device, such as an electric vehicle. As a result, the battery pack system can be applied to various electrically powered devices, facilitating a high degree of standardization. Furthermore, since the two battery modules can be connected with their housing sides facing each other using the connecting portion, the battery pack can be maintained in a stable position as designed, compared to conventional methods of fastening the battery modules with bands or the like. This enables efficient and stable placement in various spaces, not just cubic spaces, thereby increasing the degree of standardization of the battery pack. Furthermore, some battery modules can be easily separated by releasing the connecting portion, resulting in excellent maintainability.

[0009] (2) In the battery pack system according to (1), the housing of each battery module has a polygonal upper and lower end faces, and this configuration allows the battery modules to be connected to each other in a more diverse and stable manner, thereby increasing the degree of commonality of battery packs.

[0010] (3) The battery pack system according to (2), wherein the connecting portion has an engaging portion and an engaged portion that are structured to engage with each other, and the engaging portion is provided on a pair of flat side surfaces of the prismatic housing that are symmetrical with respect to the axis. This configuration allows the battery modules to be connected to each other in a more stable position, and also facilitates attachment and detachment, thereby improving maintainability.

[0011] (4) The battery module according to (3), wherein the engaging portion and the engaged portion comprise a dovetail-shaped or T-slot-shaped recess extending in the axial direction, and a protrusion that fits into the recess and engages with the groove so as to be movable relative to the groove in the axial direction. This configuration allows the battery modules to be connected together in a more stable position, and also makes attachment and detachment easier, further improving maintainability.

[0012] (5) A battery pack system including a coupler that electrically couples the two battery modules coupled by the coupling parts, the coupler including a pair of connectors coupled to each upper end surface or each lower end surface of the battery modules and having coupling terminals electrically connected to the terminal parts provided on those surfaces, and a coupling wire provided between the connectors and electrically connecting the coupling terminals. With this configuration, the battery modules coupled laterally by the coupling parts can be electrically connected to each other through the coupler, allowing for a wider variety of arrangements of the battery modules and enabling more efficient arrangement in a variety of spaces.

[0013] (6) The battery pack system according to any one of (1) to (5), wherein the battery module includes a first positive terminal and a first negative terminal as the electrodes on the upper end surface, a second positive terminal and a second negative terminal as the electrodes on the lower end surface, a positive side path portion for flowing a current between the first positive terminal and the second positive terminal, a negative side path portion for flowing a current between the second negative terminal and the first negative terminal, and a switching circuit that switches a connection state of a current path in at least one of the positive side path portion and the negative side path portion, the connection state including an adding state in which the power storage unit is added to the current path and a removing state in which the power storage unit is removed from the current path.

[0014] With this configuration, the number of series connections of the storage units can be dynamically changed using a switching circuit to change the output waveform, making it possible to adapt the voltage waveform required for each electric device and further increasing the degree of commonality.

[0015] (7) A battery module used in a battery pack system according to any one of (1) to (6), wherein one or more storage units are housed inside a housing, the housing has terminal portions serving as electrodes on the upper and lower end surfaces, the battery modules are electrically connectable via the terminal portions, and a connecting portion is provided on a side surface of the housing to connect two of the battery modules together with the side surfaces of the housing facing each other.

[0016] (8) A coupler used in the battery pack system described in any one of (1) to (6) and electrically connecting two battery modules connected by the connecting portion, the coupler comprising: a pair of connectors connected to each upper end surface or each lower end surface of the battery modules and having connecting terminals electrically connected to the terminal portions provided on those surfaces; and a connecting wire provided between the connectors and electrically connecting each connecting terminal to each other.

[0017] According to the present invention, it is possible to freely change electrical specifications such as voltage according to the application, and to efficiently arrange battery packs in various spaces, thereby increasing the degree of commonality of battery packs and providing a battery pack system that is also easy to maintain.

[0018] 1 is an explanatory diagram showing an example of connecting multiple battery modules according to an embodiment of the present invention. FIG. 1 is a perspective view schematically showing the appearance of a battery module. FIG. 2 is a plan view of the appearance of the same battery module. FIG. 3 is an explanatory view showing a power storage unit inside a housing of a battery module. FIG. 4 is an explanatory view showing a power storage unit inside a housing of a battery module. FIG. 5 is an explanatory view showing a state in which multiple battery modules are connected laterally by a connecting unit. FIG. 6 is a longitudinal sectional view showing the housing structure of a battery module. FIG. 7 is a perspective view showing a coupler. FIG. 8 is a longitudinal sectional view showing a coupler. FIG. 9 is an explanatory view showing a modified example of a terminal unit. FIG. 10 is an explanatory view showing an example of the configuration of a battery pack system formed by connecting multiple battery modules. FIG. 11 is a perspective view showing the appearance of an end module as seen from the top side. FIG. 12 is a perspective view showing the appearance of an end module as seen from the bottom side. FIG. 13 is a longitudinal sectional view showing the housing structure of the end module. FIG. 14 is a perspective view of the appearance of a paralleling module. FIG. 15 is a plan view of the appearance of the same paralleling module. FIG. 16 is an explanatory view showing a coupler that connects paralleling modules. FIG. 17 is an explanatory view showing a state in which multiple paralleling modules are connected by a coupler. FIG. 18 is an explanatory view showing a modified example of a series block. FIG. 19 is an explanatory view showing a modified example of a series block. A block diagram schematically showing an example of the electrical configuration of the series block shown in Figure 9. A schematic circuit diagram for explaining the configuration of a unit module. A conceptual circuit diagram showing an example of a unit module EM using a full bridge as a switching circuit. An explanatory diagram for explaining parallel connection of series blocks.

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. A battery pack system 1 according to the present invention is a system formed by connecting a plurality of battery modules 2. Fig. 1 shows an example of a configuration (battery string) in which a plurality of battery modules 2 are connected.

[0020] The outer shape of the housing 20 of the battery module 2 is a prism with an upper end surface 20a and a lower end surface 20b that are polygonal, more specifically, a hexagonal prism with an upper end surface 20a and a lower end surface 20b that are regular hexagons. As shown in Figures 4A and 4B , the battery module 2 houses one or more battery cells as a power storage unit B1 inside the housing 20.

[0021] As shown in FIGS. 2 and 3 , terminals 24A and 24B serving as electrodes are provided on the upper end surface 20a and the lower end surface 20b of the housing 20, respectively, and multiple battery modules 2 are electrically connected via these terminals 24A and 24B. In this example, the terminals 24A and 24B are formed of six annular electrodes, namely, a main electrode (positive) d1, a main electrode (negative) d2, a control power electrode (positive) d3, a control power electrode (negative) d4, a communication line electrode (positive) d5, and a communication line electrode (negative) d6, arranged concentrically and radially spaced apart from one another around the central axis of the battery module 2. The type, number, and arrangement of the electrodes are not limited to those shown in this example. For example, by wireless communication, the communication line electrodes d5 and d6 can be omitted, thereby reducing the number of electrodes.

[0022] The concentric annular electrode arrangement as in this example is efficient because it allows the same connector 6, described below, to be used to electrically connect the battery modules 2 connected to either side of the polyhedron. However, it is not essential to arrange the electrodes in an annular shape. For example, as shown in FIG. 8, even if the electrodes d1 to d6 are provided discretely at corresponding positions on each side, the same effect as in the annular electrode arrangement can be obtained by arranging the electrodes d1 to d6 of the connector 6 correspondingly. Furthermore, it is preferable that the electrodes d1 to d6 of the terminal portions 24A, 24B have a touchproof structure.

[0023] 6, through holes 27 are provided at the center of the upper end surface 20a and the lower end surface 20b of the housing 20, connecting the interior and exterior spaces of the housing 20. A cooling refrigerant such as air can be circulated through the gaps within the housing 20 through these upper and lower through holes 27, as shown by the arrows in the figure, and this makes it possible to dissipate heat inside each housing 20 to the outside.

[0024] Furthermore, a connecting portion 25 that connects the two battery modules 2 with the side surfaces of the housing facing each other is provided on the side surface 20c of the housing 20. As shown in Figures 2 and 3, the connecting portion 25 has an engaging portion 70 and an engaged portion 71 that are structured to engage with each other and are provided on a pair of side surfaces 20c that are symmetrical with respect to the axis among the plurality of flat side surfaces 20c of the prismatic housing 20.

[0025] The structures of the engaging portion 70 and the engaged portion 71 are not particularly limited, but a preferred example, as in this example, is one in which the engaging portion 70 is provided with a dovetail-shaped or T-groove-shaped recess extending in the axial direction (vertical direction), and the engaged portion 71 is made up of a protrusion that has a shape that fits into the engaging portion 70 and engages with the recess so as to be movable relative to the axial direction. This allows for easy connection / disconnection by sliding up and down, and also allows for connection by being turned upside down.

[0026] When the housing 20 has a hexagonal prism shape as in this example, it is preferable to provide such connecting portions 25 alternately so that the engaging portions 70 and the engaged portions 71 are aligned on two adjacent side surfaces, since this allows the opposing side surfaces to be firmly connected together in an engaged state between the engaging portions 70 and the engaged portions 71 when a plurality of battery modules 2 are arranged densely in the horizontal direction as shown in Fig. 5. Although the connecting portions 25 are provided on each side surface 20c, they do not need to be provided on all side surfaces.

[0027] Furthermore, vertical connecting portions 26 that vertically connect the two battery modules 2 are provided on the upper end surface 20a and the lower end surface 20b of the housing 20. The structure of the vertical connecting portion 26 is not particularly limited, and various forms are possible, such as one in which an engaging portion and an engaged portion are provided on the housing 20, or one in which the terminal portions 24A, 24B are structured as male and female terminals and are connected to each other.

[0028] When battery modules 2 are connected vertically via vertical connectors 26, the facing terminals 24A, 24B are also electrically connected to each other. This vertical connection also makes it possible to arrange battery modules 2 (battery strings 3) as shown in Figures 16A and 16B . Furthermore, the through-holes 27 on the facing upper and lower end faces 20a, 20b of vertically connected battery modules 2 also face each other at the same positions (centers), allowing the refrigerant to be transferred between battery modules 2 and circulating through multiple battery modules 2 as indicated by the dashed-dotted arrows in the figures.

[0029] 1 , in the horizontal connection configuration of the battery modules 2 in this example, a coupler 6 is provided between two adjacent battery modules 2 that are horizontally connected by the above-described connecting portion 25, for electrically connecting these two battery modules 2. Specifically, the coupler 6 has a pair of connecting bodies 61 that are connected to the upper end faces 20 a (or lower end faces 20 b) of each battery module 2 and have connecting terminals 60A provided on opposing faces (connecting faces 61 a) that are electrically connected to the terminal portions 24 A (24 B) provided on the upper end faces 20 a (or lower end faces 20 b) of the battery modules 2, and a connecting portion 62 that is provided between the connecting bodies 61 and has built-in connecting wires 60 C that electrically connect the connecting terminals 60 A to each other.

[0030] Specifically, the connecting terminal 60A corresponds to the terminal portion 24A and has, in order from the outer periphery, a main electrode (positive) d1, a main electrode (negative) d2, a control power electrode (positive) d3, a control power electrode (negative) d4, a communication line electrode (positive) d5, and a communication line electrode (negative) d6, for a total of six annular electrodes, and each of the electrodes of each connecting body 61 is connected by a connecting wire.

[0031] The planar shape of each connector 61 of the coupler 6 is the same as the top end surface 20a of each battery module 2 to which it is connected (hexagonal in this example), and is provided with a connecting structure that engages with the vertical connecting portion 26 provided on the top end surface 20a. Various configurations are possible, such as those that provide an engaging portion or an engaged portion, or those that connect the terminal portions 24A, 60A as male and female terminals.

[0032] By connecting the battery modules 2 with such connectors 6, it is possible to connect the battery modules 2 in an appropriate direction by selecting from multiple side surfaces (six side surfaces at 60-degree intervals in this example). This allows for free horizontal placement, and multiple battery modules 2 can be efficiently placed even in a cylindrical space such as a storage space for a car spare tire.

[0033] 7A and 7B , a through-hole 63 is provided in the center of the connection surface 61 a of each connector 61, facing the position (center) of each of the above-mentioned through-holes 27 in the opposing upper end face 20 a or lower end face 20 b of the battery module 2, and through which refrigerant is transferred between the battery modules 2. A refrigerant flow path 64 is provided inside the coupler 6, which is made up of the connector 61 and the joining portion 62, for transferring refrigerant that flows in from one through-hole 63 and discharges it from the other through-hole 63. This allows the coupler 6 to receive refrigerant from one of the connected battery modules 2, circulate it through the flow path 64, and then transfer it to the other battery module 2, and at the same time, is configured to dissipate heat trapped inside to the refrigerant.

[0034] A more specific configuration example of the battery pack system 1 formed by connecting a plurality of battery modules 2 as described above will be described below.

[0035] For example, in the configuration example shown in FIG. 9 , an end module 4 is connected to one end of a battery string 3 in which multiple battery modules 2 are connected horizontally, and a paralleling module 5 is connected to the other end of the battery string 3. In this example, multiple battery modules 2 are connected two-dimensionally horizontally. However, various other configurations are possible, such as two-dimensional connections vertically and horizontally as shown in FIGS. 16A and 16B , or three-dimensional connections that combine these. A battery pack system is configured by connecting multiple series blocks 11, each of which connects a paralleling module 5, a battery string 3, and an end module 4, via the paralleling modules 5. The end module 4 and the paralleling module 5 basically have the same connection structure (connecting portions 25, specifically, engaging portions 70 and engaged portions 71) as the battery module 2 and are detachable from the battery modules 2 at the ends of the battery string 3.

[0036] 10 and 11, the outer shape and size of the housing 40 of the end module 4 are substantially the same as those of the housing 20 of the battery module 2, and the upper end face 40a and the lower end face 40b are also polygonal prism shapes, more specifically, the upper end faces and the lower end faces are regular hexagonal prisms. However, unlike the battery module 2, the housing 40 does not house a power storage unit.

[0037] 10 , the upper end surface 40a of the end module 4 is provided with a terminal portion 43A, similar to the upper end surface 20a of each battery module 2, and is electrically connected to the adjacent battery module 2 via the coupler 6. Specifically, a total of six annular electrodes are provided, in order from the outer periphery: a main electrode (positive) d1, a main electrode (negative) d2, a control power electrode (positive) d3, a control power electrode (negative) d4, a communication line electrode (positive) d5, and a communication line electrode (negative) d6. The other lower end surface 40b does not have a terminal portion.

[0038] The upper end surface 40a is provided with a similar vertical connecting portion 46 that connects to the vertical connecting portion 26 on the lower end surface 20b of the battery module 2. Various configurations are possible, such as those with an engaging portion or an engaged portion, or those in which the terminal portion 43A and the terminal portion 24B on the battery module 2 connected thereto are structured as male and female terminals that can be connected to each other. In this example, the connection is made by the connecting structure of the coupler 6.

[0039] Furthermore, a through-hole 47 is provided in the center of the upper end surface 40a, corresponding to the position (center) of the through-hole 27 in the lower end surface 20b of the connectable battery module 2 and the position of the through-hole 63 in the connector 61 of the coupler 6, and enabling the transfer of refrigerant between the battery module 2. A through-hole 48 that communicates between the interior and exterior spaces of the housing 40 is also provided in the lower end surface 40b, as shown in FIG.

[0040] This through hole 48 serves as an inlet for taking in a refrigerant into the series block 11 or an outlet for the refrigerant from the series block 11, and is equipped with a filter 49. The end module 4 circulates a cooling refrigerant, such as air, through the gaps in the housing 40 through the upper and lower through holes 47, 48. It is preferable to provide a pump, such as a fan 490, inside the housing 40 of the end module 4, as shown in FIG. 12, to forcibly circulate the refrigerant.

[0041] 13 and 14 , the external shape and size of the housing 50 of the parallelization module 5 are the same as those of the housing 20 of the battery module 2, and the upper end face 50 a and the lower end face 50 b are also polygonal prism shapes, more specifically, the upper end faces and the lower end faces are regular hexagonal prisms. However, unlike the battery module 2, no power storage unit is housed inside the housing 50.

[0042] Terminals 53A, 53B are provided on the upper end surface 50a and the lower end surface 50b of the paralleling module 5 for electrical connection with the battery modules 2 and the coupler 6, and are electrically connected to adjacent battery modules 2 through the coupler 6. Specifically, a total of six annular electrodes are provided corresponding to the terminals 24A, 24B, in order from the outer periphery: a main electrode (positive) d1, a main electrode (negative) d2, a control power electrode (positive) d3, a control power electrode (negative) d4, a communication line electrode (positive) d5, and a communication line electrode (negative) d6.

[0043] The upper end surface 50a and the lower end surface 50b are provided with similar vertical connecting portions 56 that are connected to the vertical connecting portions 26 of the battery modules 2. Various configurations are possible, such as those with engaging or engaged portions, or those in which the terminal portions 53A, 53B and the terminal portions 24B, 24A on the battery module 2 connected thereto are structured as male and female terminals that can be connected to each other. In this example, the connection is made by the connecting structure of the coupler 6.

[0044] In addition, at the center of the upper end surface 50a and the lower end surface 50b, a through hole 57 is provided which corresponds to the position (center) of the above-mentioned through hole 27 of the connectable battery module 2 and the position of the through hole 63 of the connector 61 of the coupler 6, and which allows for the transfer of refrigerant between the battery module 2.

[0045] 15A and 15B , a coupler 8 is attached to the parallelizing module 5 for connecting it to parallelizing modules 5 that constitute other series blocks. In order to enable a plurality of parallelizing modules 5 to be connected to one parallelizing module 5, the coupler 8 is configured to include a pair of triangular connectors 81 in plan view, each of which is attached to a triangular region obtained by dividing a polygon on the upper or lower end surface of the parallelizing module by a diagonal line passing through the center (divided into six in this example), and which has, on opposing surfaces (connection surfaces 81 a), connecting terminals 80A extending in an arc shape and electrically connected to the arc-shaped terminal portions 53A (53B) of the parallelizing modules 5 located within the triangular region, and a connecting portion 82 provided between the connectors 81 and incorporating connecting wires 80C that electrically connect the connecting terminals 80A to each other.

[0046] Specifically, the connecting terminal 80A corresponds to the terminal portion 53A and has, in order from the side closest to the connecting portion 82, a total of six concentric arc-shaped electrodes: a main electrode (positive) d1, a main electrode (negative) d2, a control power supply electrode (positive) d3, a control power supply electrode (negative) d4, a communication line electrode (positive) d5, and a communication line electrode (negative) d6, and the electrodes of each connecting body 81 are connected to each other by connecting wires. Each connecting body 81 of the coupler 8 is provided with a connecting structure that engages with a vertical connecting portion provided on the upper end surface 50a. Various configurations are possible, such as those that have an engaging portion or an engaged portion, or those that connect the terminal portions 53A, 80A to each other as male and female terminals.

[0047] By connecting the parallelization modules 5 using such connectors 8, the parallelization modules 5 can be connected in an appropriate direction on multiple side surfaces (six side surfaces at 60-degree intervals in this example). Furthermore, as shown in FIG. 15B , multiple parallelization modules 5 can be connected to one parallelization module 5. In a preferred embodiment, one of the multiple parallelization modules 5 connected using connectors 8 in this manner is configured as a master with output terminals (+ / -) (output terminal (+) Tpo and output terminal (-) Tmo in FIG. 20 ), and the other parallelization modules 5 are configured as slaves. Such output terminals can be provided in appropriate locations on the housing 50 of the master parallelization module 5. Two or more or all of the parallelization modules 5 may be masters. Furthermore, since the terminal portions 53A / 53B are partially exposed on the top and bottom end surfaces of the parallelization module 5 except in the areas where the connectors 6 / 8 are provided, it is preferable to provide a protective cap to cover the exposed areas or the entire end surfaces.

[0048] When multiple battery modules 2 are connected via couplers 6, the main electrode (positive) d1, main electrode (negative) d2, control power electrode (positive) d3, control power electrode (negative) d4, communication line electrode (positive) d5, and communication line electrode (negative) d6 of one of the adjacent battery modules 2 are connected via the couplers 6 to the main electrode (positive) d1, main electrode (negative) d2, control power electrode (positive) d3, control power electrode (negative) d4, communication line electrode (positive) d5, and communication line electrode (negative) d6 of the other battery module.

[0049] Furthermore, when the battery module 2 and the end module 4 are connected via the coupler 6, the main electrode (positive) d1, main electrode (negative) d2, control power electrode (positive) d3, control power electrode (negative) d4, communication line electrode (positive) d5, and communication line electrode (negative) d6 on one side are similarly connected to the main electrode (positive) d1, main electrode (negative) d2, control power electrode (positive) d3, control power electrode (negative) d4, communication line electrode (positive) d5, and communication line electrode (negative) d6 on the other side via the coupler 6, respectively.

[0050] Similarly, when the battery module 2 and the paralleling module 5 are connected via the coupler 6, the main electrode (positive) d1, main electrode (negative) d2, control power electrode (positive) d3, control power electrode (negative) d4, communication line electrode (positive) d5, and communication line electrode (negative) d6 on one side are connected to the main electrode (positive) d1, main electrode (negative) d2, control power electrode (positive) d3, control power electrode (negative) d4, communication line electrode (positive) d5, and communication line electrode (negative) d6 on the other side via the coupler 6. When a plurality of series blocks 11, in which the battery modules 2, end modules 4, and paralleling modules 5 are connected via the couplers 6 in this way, are connected, between adjacent paralleling modules 5, the main electrode (positive) d1 and main electrode (negative) d2 on one side are connected to the main electrode (positive) d1 and main electrode (negative) d2 on the other side.

[0051] FIG. 17 is a block diagram illustrating an example of the electrical configuration of a series block 11. The coupler 6 is omitted, and only two battery modules 2 are shown. The housing of each battery module 2 includes a positive path 21 for passing current between the main electrode (positive) d1 on the upper end surface and the main electrode (positive) d1 on the lower end surface, a negative path 22 for passing current between the main electrode (negative) d2 on the upper end surface and the main electrode (negative) d2 on the lower end surface, and an intra-module control unit 23. The positive path 21 and the negative path 22 each include multiple unit modules EM (power storage units (battery cells) B1). Each unit module EM includes a terminal T1 (first terminal) and a terminal T2 (second terminal). For reference, "(top)" in the figure indicates the electrode on the upper end surface, and "(bottom)" indicates the electrode on the lower end surface.

[0052] The multiple unit modules EM in the positive-side path section 21 are connected in series, and between adjacent unit modules EM, the terminal T2 of the unit module EM on the higher potential side is connected to the terminal T1 of the unit module EM on the lower potential side. The terminal T1 of the unit module EM on the highest potential side is connected to one main electrode (positive) d1, and the terminal T2 of the unit module EM on the lowest potential side is connected to the other main electrode (positive) d1. As a result, the positive-side path section 21 forms a current path from one main electrode (positive) d1 to the other main electrode (positive) d1.

[0053] The negative-side path section 22 is configured similarly to the positive-side path section 21, except that the terminal T1 of the unit module EM on the highest potential side is connected to one main electrode (negative) d2, and the terminal T2 of the unit module EM on the lowest potential side is connected to the other main electrode (negative) d2. As a result, the negative-side path section 22 forms a current path from one main electrode (negative) d2 to the other main electrode (negative) d2. Note that the number of unit modules EM in the positive-side path section 21, i.e., the number of power storage units B1, may be one, and the number of unit modules EM in the negative-side path section 22, i.e., the number of power storage units B1, may be one.

[0054] Fig. 18 is a schematic circuit diagram for explaining the configuration of a unit module EM. The unit module EM includes terminals T1 and T2, a power storage unit B1 that stores electric charge, and switching elements SW1 and SW2 (switching circuit) that switch the electrical connection state of the power storage unit B1 to the terminals T1 and T2. The switching elements SW1 and SW2 are an example of a switching circuit, and in the example shown in Fig. 18, form a half bridge.

[0055] Specifically, the power storage unit B1 and the switching element SW1 are connected in series, and the switching element SW2 is connected in parallel to the series circuit of the power storage unit B1 and the switching element SW1. The connection point between the switching elements SW1 and SW2 is connected to the terminal T1, and the connection point between the switching element SW2 and the power storage unit B1 is connected to the terminal T2.

[0056] The terminal T1 is connected to the terminal T2 of the unit module EM that is on the higher potential side than the own module, and the terminal T2 is connected to the terminal T1 of the unit module EM that is on the lower potential side than the own module. In this way, a plurality of unit modules EM are connected in series. Various switching elements can be used as the switching elements SW1 and SW2, and semiconductor switching elements such as transistors can be suitably used, for example. The switching elements SW1 and SW2 are turned on and off in response to a control signal from the intra-module control unit 23.

[0057] The power storage unit B1 of the unit module EM indicated by symbol A is in a connected state, and the power storage unit B1 of the unit module EM indicated by symbol B is in a disconnected state. In the connected state, the switching element SW1 is turned on and the switching element SW2 is turned off, thereby connecting the power storage unit B1 to the current paths of the positive side path portion 21 and the negative side path portion 22. In the disconnected state, the switching element SW1 is turned off and the switching element SW2 is turned on, thereby disconnecting the power storage unit B1 from the current paths of the positive side path portion 21 and the negative side path portion 22.

[0058] The unit module EM may use a full bridge as a switching circuit. Fig. 19 is a conceptual circuit diagram showing an example of a unit module EM using a full bridge as a switching circuit. The full-bridge unit module EM shown in Fig. 19 further includes switching elements SW3 and SW4 in addition to the half-bridge unit module EM shown in Fig. 18. The switching elements SW3 and SW4 may be the same as the switching elements SW1 and SW2.

[0059] Specifically, a series circuit of switching elements SW3 and SW4 is connected in parallel to a series circuit of switching elements SW1 and SW2. The connection point of switching elements SW1 and SW2 is connected to terminal T1, and the connection point of switching elements SW3 and SW4 is connected to terminal T2. The full-bridge unit module EM shown in Fig. 19 can be in an inverted state indicated by symbol C in addition to an added state indicated by symbol A and a removed state indicated by symbol B. In the unit module EM in the inverted state, the power storage unit B1 is connected with its polarity reversed.

[0060] In the join state, switching elements SW1 and SW4 are on and switching elements SW2 and SW3 are off. In the detach state, switching elements SW1 and SW3 are off and switching elements SW2 and SW4 are on. In the inverted state, switching elements SW1 and SW4 are off and switching elements SW2 and SW3 are on. Note that in the detach state, switching elements SW1 and SW3 may be on and switching elements SW2 and SW4 may be off.

[0061] The intra-module control unit 23 shown in FIG. 17 is configured to include, for example, a CPU (Central Processing Unit) that executes predetermined logical operations, a RAM (Random Access Memory) that temporarily stores data, a non-volatile storage device, a serial communication circuit, and peripheral circuits therefor, and operates by executing a predetermined program.

[0062] The intra-module control unit 23 turns on and off the switching elements SW1 and SW2 in accordance with control information obtained from the communication line electrode (positive) d5, and switches the connection state of each unit module EM in the battery module 2. Hereinafter, the intra-module control unit 23 controlling the switching elements SW1 and SW2 to control the connection state including the connection state and the disconnection state, or controlling the switching elements SW1 to SW4 to control the connection state including the connection state, the disconnection state, and the inverted state, will be simply referred to as controlling the connection state.

[0063] As shown in FIG. 17 , the end module 4 includes inductors L1 and L2, an end control unit 41, and a current sensor 42 within its housing. One end of the inductor L1 is connected to the positive main electrode d1, and the other end of the inductor L1 is connected to one end of the inductor L2, which is connected to the negative main electrode d2. That is, the inductors L1 and L2 are interposed between the positive main electrode d1 and the negative main electrode d2. The connection point between the inductors L1 and L2, i.e., the midpoint of the inductors L1 and L2, is conductively connected to the intermediate connection terminal Ti. Note that a center-tapped reactor may be used instead of the inductors L1 and L2, and the center tap may be connected to the intermediate connection terminal Ti. The intermediate connection terminal Ti is provided at an appropriate location on the outer surface of the housing 40, as shown in FIG. 11 .

[0064] The inclusion of inductors L1 and L2 in the end module 4 enables the battery pack system 1 to operate as an inverter circuit. Note that the end module 4 does not necessarily have to include inductors L1 and L2 and the intermediate connection terminal Ti, and the main electrode (positive) d1 and the main electrode (negative) d2 may be short-circuited. The current sensor 42 detects the current flowing through the battery string 3 and outputs the current value to the end control unit 41.

[0065] The end control unit 41 is configured to include, for example, a CPU that executes predetermined logical operations, a RAM that temporarily stores data, a non-volatile storage device, a serial communication circuit, and peripheral circuits thereof, and operates by executing a predetermined program. The end control unit 41 transmits the current value detected by the current sensor 42 as a second serial signal SS2 (second signal) to the communication line electrode (negative) d6.

[0066] The paralleling module 5 includes, within its housing, a control unit 51 and a filter 52. The filter 52 is a so-called LC filter that includes an inductor L interposed between the main electrodes (positive) d1 and a capacitor C interposed between the main electrodes (positive) d1 and (negative) d2.

[0067] The control unit 51 is configured to include, for example, a CPU that executes predetermined logical operations, a RAM that temporarily stores data, a non-volatile storage device, a serial communication circuit, and peripheral circuits thereof, and operates by executing a predetermined program. The control unit 51 outputs control information for each battery module 2 and end module 4 as a first serial signal SS1 (first signal) that is connected in the order in which the multiple battery modules 2 and end modules 4 are connected in the series block 11, to the communication line electrode (positive) d5 of an adjacent battery module 2 via the communication line electrode (positive) d5.

[0068] Although the first serial signal SS1 is shown as an example of the first signal and the second serial signal SS2 is shown as an example of the second signal, the first signal and the second signal may be parallel signals. The communication line electrode (positive) d5 and the communication line electrode (negative) d6 may be configured as connectors in which conductors contact each other. Alternatively, they may be configured to be connected one-to-one by non-contact means such as radio waves or light.

[0069] When the plurality of battery modules 2, end modules 4, and paralleling modules 5 configured as described above are connected, the power storage units B1 in the joined state in all the battery modules 2 are connected in series via inductors L1 and L2, and the sum of the output voltages of the power storage units B1 is output. Since the battery pack system 1 can increase or decrease the number of connected battery modules 2, the output voltage can be changed by increasing or decreasing the number of battery modules 2 according to the voltage required for each electrically powered device, such as an electric vehicle. Therefore, the battery pack system 1 can be applied to various electrically powered devices, making it easy to increase the degree of standardization.

[0070] Furthermore, since the number of joined power storage units B1 can be dynamically changed using the control information, it becomes possible to finely adjust the output voltage according to the state of charge and output voltage of the power storage units B1. Furthermore, when the end module 4 is configured to include inductors L1, L2 and an intermediate connection terminal Ti, it becomes possible to operate the battery pack system 1 as an inverter circuit, and to output a single-phase AC voltage from the intermediate connection terminal Ti using two battery pack systems 1, and to output a three-phase AC voltage from the intermediate connection terminal Ti using three battery pack systems 1.

[0071] Next, the parallel connection of the series blocks 11 will be described. Fig. 20 is an explanatory diagram for explaining the parallel connection of the series blocks 11. Fig. 20 omits the illustration of the coupler 6, the filter 52, the inductors L1 and L2, and the intermediate connection terminal Ti.

[0072] When multiple series blocks 11 are connected, as shown in FIG. 20 , the main electrodes (positive) d1 and (negative) d2 on one side are connected to the main electrodes (positive) d1 and (negative) d2 on the other side by couplers 8 between the paralleling modules 5. As a result, multiple series blocks 11 are connected in parallel. This increases the current capacity output between the main electrodes (positive) d1 and (negative) d2. In this way, by using the paralleling modules 5, the number of series blocks 11 connected in parallel can be easily increased or decreased. As a result, the current capacity of the battery pack system 1 can be easily changed. Therefore, the battery pack system 1 can easily be adjusted to have a current capacity according to the current required for each electrically powered device, such as an electric vehicle.

[0073] Furthermore, when multiple series blocks 11 are connected in parallel and the unit modules EM of each series block 11 are switched by MMC control or the like, differences in instantaneous output voltages occur between the series blocks 11. This undesirably results in repeated instantaneous current inputs and outputs between the series blocks 11. Therefore, by providing a filter 52 in the paralleling module 5 to smooth the output voltage of each series block 11, it is possible to reduce the instantaneous current inputs and outputs between the series blocks 11.

[0074] It should be noted that the paralleling module 5 does not necessarily need to be provided with a filter 52 or a control unit 51. A control unit may be provided outside the paralleling module 5, or a single control unit may control multiple series blocks 11. The control unit 51 may also be provided in the end control unit 41. The control unit 51 may not be provided, and may be provided outside the battery pack system 1. It is also possible to not provide the paralleling module 5, and to short-circuit the main electrode (positive) d1 and the main electrode (negative) d2 with a polarity bus bar or a negative electrode bus bar. Various other circuit configurations are possible, and are not limited to the examples given in this embodiment.

[0075] REFERENCE SIGNS LIST 1 Battery pack system 2 Battery module 3 Battery string 4 End module 5 Paralleling module 6 Coupler 8 Coupler 11 Series block 20 Housing 20a Upper end surface 20b Lower end surface 20c Side surface 21 Positive path section 22 Negative path section 23 In-module control section 24A, 24B Terminal section 25 Connection section 26 Vertical connection section 27 Through hole 40 Housing 40a Upper end surface 40b Lower end surface 41 End control section 42 Current sensor 43A Terminal section 46 Vertical connection section 47, 48 Through hole 49 Filter 490 Fan 50 Housing 50a Upper end surface 50b Lower end surface 51 Control section 52 Filter 53A, 53B Terminal section 56 Vertical connection section 57 Through hole 60A Connecting terminal 60C Connecting wire 61 Connecting body 61a Connecting surface 62 Connecting portion 63 Through hole 64 Flow path 70 Engaging portion 71 Engaged portion 80A Connecting terminal 80C Connecting wire 81 Connecting body 81a Connecting surface 82 Connecting portion B1 Power storage portion C Capacitor D1 to D4 Control information EM Unit module L Inductor M1 to M4 Module information SS1 First serial signal SS2 Second serial signal SW1 to SW4 Switching elements T1, T2 Terminal Ti Intermediate connecting terminal d1 Main electrode (positive) d2 Main electrode (negative) d3 Control power electrode (positive) d4 Control power electrode (negative) d5 Communication line electrode (positive) d6 Communication line electrode (negative)

Claims

1. A battery pack system comprising a plurality of connected battery modules, wherein the battery module has one or more storage units housed inside a housing, and has terminal sections that serve as electrodes on the upper and lower end faces of the housing, the plurality of battery modules being electrically connected via the terminal sections, and a connecting section is provided on a side of the housing to connect two of the battery modules together with the sides of the housing facing each other.

2. The battery pack system according to claim 1, wherein the housing of each battery module is in the shape of a prism with polygonal upper and lower end faces.

3. A battery pack system as described in claim 2, wherein the connecting portion has an engaging portion and an engaged portion that are structured to engage with each other, on a pair of side surfaces that are symmetrical about the axis among the multiple flat side surfaces of the prismatic housing.

4. A battery module as described in claim 3, wherein the engaging portion and the engaged portion comprise a dovetail-shaped or T-groove-shaped recess extending in the axial direction, and a protrusion having a shape that fits into the recess and engages with the groove portion so as to be movable relative to the axial direction.

5. A battery pack system as described in claim 1, further comprising a connector that electrically connects the two battery modules connected by the connecting portion, the connector comprising: a pair of connectors connected to each upper end surface or each lower end surface of the battery modules and having connecting terminals that are electrically connected to the terminal portions provided on said surfaces; and connecting wires provided between these connectors and electrically connecting the connecting terminals to each other.

6. A battery pack system in which the battery module is provided with refrigerant circulation ports on the upper and lower end surfaces of the housing, respectively, for allowing refrigerant to flow in and out of the housing, and the refrigerant circulation ports are provided at corresponding positions so as to communicate with each other when the two battery modules are connected with the upper end surface of one housing facing the lower end surface of the other housing.

7. A battery pack system as claimed in claim 6, further comprising a coupler that electrically couples the two battery modules that are coupled by the coupling portion, the coupler comprising: a pair of connectors that are coupled to each of the upper end faces or each of the lower end faces of the battery modules and have coupling terminals that are electrically connected to the terminal portions provided on said faces; coupling wires that are provided between these connectors and electrically connect the coupling terminals; and a refrigerant flow passage that communicates with the refrigerant flow ports provided on each of the upper end faces or each of the lower end faces and transfers refrigerant from one refrigerant flow port to the other refrigerant flow port.

8. The battery pack system according to claim 1, wherein the battery module comprises: a first positive terminal and a first negative terminal as the electrodes on the upper end surface; a second positive terminal and a second negative terminal as the electrodes on the lower end surface; a positive side path portion for flowing current between the first positive terminal and the second positive terminal; a negative side path portion for flowing current between the second negative terminal and the first negative terminal; and a switching circuit for switching connection states in the current path of at least one of the positive side path portion and the negative side path portion, including an insertion state in which the storage unit is inserted into the current path and a removal state in which the storage unit is removed from the current path.

9. A battery module for use in a battery pack system according to any one of claims 1 to 8, wherein one or more storage units are housed inside a housing, the housing has terminal sections that serve as electrodes on the upper and lower end faces, and the battery modules can be electrically connected via the terminal sections, and a connecting section is provided on a side of the housing to connect two of the battery modules with the sides of the housing facing each other.

10. A coupler used in a battery pack system according to any one of claims 1 to 8, electrically connecting two battery modules connected by the connecting part, comprising: a pair of connectors connected to the upper end faces or lower end faces of the battery modules, each having connecting terminals electrically connected to the terminal parts provided on said faces; and a connecting wire provided between these connectors, electrically connecting the connecting terminals to each other.

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