Module battery and method for using same

Abstract

Provided is a highly convenient module battery in which a main electrode bus bar and a conductive member can be connected by a method ensuring high connection reliability when high connection reliability of the main electrode bus bar and the conductive member is required as in the case of actual use, and the main electrode bus bar and the conductive member can be quickly and easily connected when quick and simple connection of the main electrode bus bar and the conductive member is required as in the case of a charge / discharge test prior to shipment. The module battery comprises: a housing; a plurality of unit cells housed in the housing and connected in series and / or in parallel; a positive electrode bus bar exposed to the outside of the housing and electrically connected to the plurality of unit cells; and a negative electrode bus bar exposed to the outside of the housing and electrically connected to the plurality of unit cells. One or both of the positive electrode bus bar and the negative electrode bus bar have: a bolt hole that enables bolt fastening with a first conductive member; and a male or female connector part that can be fitted with a second conductive member.

Description

Module Battery and Method of Using the Same

[0001] The present invention relates to a module battery including a plurality of unit cells connected in series and / or parallel. In particular, the present invention relates to a battery module of a sodium-sulfur battery that can be used as a secondary battery for power storage and the like.

[0002] Compared with common generators, storage batteries can change output power at a higher speed, and are effective for frequency adjustment of power systems, adjustment of the difference between power generated from natural energy power generation devices and planned output power, and adjustment of power demand and power supply in power systems.

[0003] Examples of high-temperature operation type storage batteries connected to power systems include sodium-sulfur batteries (hereinafter also referred to as "NAS batteries"). An NAS battery has a bottomed cylindrical component made of a solid electrolyte such as β-alumina arranged in a metal container on the positive electrode side that serves as a storage case; sodium as a negative electrode active material is accommodated inside the bottomed cylindrical component, and sulfur as a positive electrode active material is accommodated outside the component. During discharging, ionized sodium permeates the solid electrolyte and reacts with sulfur to generate electricity when sodium polysulfide is produced; conversely, through the reverse reaction, sodium and sulfur are produced to achieve charging.

[0004] NAS batteries are generally provided as module batteries by accommodating a plurality of unit cells connected in series and / or parallel in a box. Furthermore, it is also possible to provide a large-scale container-type battery by interconnecting a plurality of module batteries and accommodating them together with control equipment in a container.

[0005] Module batteries are equipped with main electrode busbars (positive electrode busbar and negative electrode busbar) for connecting to conductive materials such as power cables. One method for connecting conductive materials to the main electrode busbars is the connector type, as described in Japanese Patent Application Publication No. 2001-243938, in which a socket portion connected to the end of a power cable is fitted into a plug portion provided on the main electrode busbar. Another known method is the one described in International Publication No. 2015 / 037439, in which bolt holes are provided in the conductor connection portion of the main electrode busbar and the connection portion of the conductive material, and the two are fastened together with bolts.

[0006] Japanese Patent Publication No. 2001-243938, International Publication No. 2015 / 037439

[0007] During actual use after the battery module has been delivered to the installation site, a high level of connection reliability is required to ensure that the conductive components connected to the main electrode busbar do not easily detach. On the other hand, during charge and discharge testing of the battery module before shipment, simplicity and speed are required. However, until now, no battery module has existed that satisfies both needs.

[0008] In view of the above circumstances, in one embodiment of the present invention, the object of providing a highly convenient module battery that can connect the main electrode busbar and conductive member in a manner that provides high connection reliability in situations where high connection reliability between the two is required, such as during actual use, and that can connect the main electrode busbar and conductive member simply and quickly in situations where simple and rapid connection between the two is required, such as during pre-shipment charge-discharge testing. In another embodiment of the present invention, the object of providing a method for using such a module battery.

[0009] The inventors have diligently studied to solve the above problems and have created the present invention as illustrated below. [Aspect 1] A module battery comprising: a box body; a plurality of single cells connected in series and / or parallel and housed in the box body; a positive electrode busbar exposed to the outside of the box body and electrically connected to the plurality of single cells; and a negative electrode busbar exposed to the outside of the box body and electrically connected to the plurality of single cells, wherein one or both of the positive electrode busbar and the negative electrode busbar have bolt holes that enable bolt fastening to a first conductive member, and a male or female connector portion that can be fitted to a second conductive member. [Aspect 2] The module battery according to Aspect 1, wherein one or both of the positive electrode busbar and the negative electrode busbar have a plate-like portion having bolt holes that enable bolt fastening to a first conductive member, and the plate-like portion also functions as a male connector portion that can be fitted to a second conductive member. [Aspect 3] The module battery according to aspect 2, wherein one or both of the positive electrode busbar and the negative electrode busbar have the plate-like portion at both left and right ends. [Aspect 4] The module battery according to aspect 2 or 3, wherein the plate-like portion has a pair of main surfaces facing each other, the arithmetic mean roughness Ra measured in accordance with JIS B0601:2013 for one of the pair of main surfaces is 0.5 to 5 μm, and the arithmetic mean roughness Ra measured in accordance with JIS B0601:2013 for the other of the pair of main surfaces is smaller than that of the other surface. [Aspect 5] The module battery according to any one of aspects 1 to 4, wherein the positive electrode busbar and the negative electrode busbar are each electrically connected to a first conductive member by bolt fastening, the first conductive member electrically connected to the positive electrode busbar is electrically connected to the negative electrode busbar of another module battery, the first conductive member electrically connected to the negative electrode busbar is electrically connected to the positive electrode busbar of yet another module battery, and neither the positive electrode busbar nor the negative electrode busbar is electrically connected to a second conductive member.[Aspect 6] The module battery according to any one of aspects 1 to 4, wherein neither the positive electrode busbar nor the negative electrode busbar is electrically connected to the first conductive member, the positive electrode busbar and the negative electrode busbar are each electrically connected to the second conductive member using the connector portion, the second conductive member electrically connected to the positive electrode busbar using the connector portion is electrically connected to the negative electrode busbar of another module battery, and the second conductive member electrically connected to the negative electrode busbar using the connector portion is electrically connected to the positive electrode busbar of yet another module battery. [Aspect 7] The module battery according to any one of aspects 1 to 6, further comprising a locking mechanism that prevents the separation of the positive electrode busbar and / or the negative electrode busbar from the second conductive member. [Aspect 8] The module battery according to aspect 7, further comprising an interlock that enables charging and discharging of the module battery only when the separation of the positive electrode busbar and / or the negative electrode busbar from the second conductive member is prevented by the locking mechanism. [Aspect 9] A module battery according to any one of aspects 1 to 8, wherein all of the plurality of single cells are sodium-sulfur batteries. [Aspect 10] A method of using a module battery according to any one of aspects 1 to 5, which includes performing charging and discharging after installation at the delivery site. [Aspect 11] A method of using a module battery according to aspect 10, which includes installing thermocouples on one or both of the contact portions where the positive electrode busbar and the first conductive member contact each other, and the contact portions where the negative electrode busbar and the first conductive member contact each other, and monitoring the temperature measured by the thermocouples when performing charging and discharging. [Aspect 12] A method of using a module battery according to any one of aspects 6 to 8, which includes performing a charge-discharge test before shipment. [Aspect 13] A method of using a module battery according to aspect 12, which includes installing thermocouples on one or both of the connector portions of the second conductive member connected to the positive electrode busbar and the connector portions of the second conductive member connected to the negative electrode busbar, and monitoring the temperature measured by the thermocouples when performing a charge-discharge test.

[0010] The module battery according to one embodiment of the present invention can connect the main electrode busbar and conductive material in a manner that provides high connection reliability when high connection reliability is required, such as in actual use, and can also connect the main electrode busbar and conductive material simply and quickly when simple and quick connection is required, such as in pre-shipment charge-discharge tests. Thus, according to one embodiment of the present invention, it is possible to provide a highly convenient module battery that can satisfy both different needs.

[0011] This shows a schematic front view of a module battery according to one embodiment of the present invention. This is a schematic cross-sectional view for illustrating the internal structure of a module battery according to one embodiment of the present invention. This is a schematic electrical circuit diagram of a plurality of single cells included in a module battery according to one embodiment of the present invention. This is a schematic partial cross-sectional view showing the vicinity of the positive electrode of a module battery according to one embodiment of the present invention. This is a schematic partial cross-sectional view showing the vicinity of the negative electrode of a module battery according to one embodiment of the present invention. This is a schematic perspective view for illustrating the structure around the positive electrode busbar in a module battery according to one embodiment of the present invention. This schematically shows how the positive electrode busbar shown in Figure 6 is electrically connected to the first conductive member by bolt fastening. This schematically shows the cross-sectional structure when the plate-shaped portion of the positive electrode busbar and the plate-shaped connecting portion of the first conductive member are bolted together. This schematically shows how the positive electrode busbar shown in Figure 6 is electrically connected to the second conductive member by fitting. This is a schematic diagram illustrating an example of the cross-sectional structure of a female connector portion. This schematic diagram illustrates an example of a method for connecting adjacent module batteries via a second conductive member. This is a schematic front view for illustrating the structure around the positive electrode busbar in a module battery according to another embodiment of the present invention.

[0012] Next, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following embodiments, and it should be understood that appropriate design changes, improvements, etc., can be made based on the ordinary knowledge of those skilled in the art, without departing from the spirit of the invention.

[0013] (1. Overall Configuration of the Module Battery) A module battery 10 according to one embodiment of the present invention has a substantially rectangular shape when viewed from above, and as shown in Figure 1, it has a box body 14 that is placed on a base 12 made of, for example, steel, and a lid body 16 that closes the opening of the box body 14. The box body 14 can be designed to be vacuum insulated. The lid body 16 can be designed to be atmospheric insulated. Inside the box body 14, as shown in Figure 2, a battery assembly 20 composed of a plurality of single cells 18 connected in series and / or parallel is housed. The module battery 10 also includes a positive electrode busbar 42 that is exposed to the outside of the box body 14 and electrically connected to the plurality of single cells 18, and a negative electrode busbar 52 that is exposed to the outside of the box body 14 and electrically connected to the plurality of single cells 18. Both the positive electrode busbar 42 and the negative electrode busbar 52 function as external connection terminals.

[0014] Each cell 18 has, for example, a cylindrical shape and is housed in the casing 14 with its axial direction parallel to the vertical. Furthermore, to address issues such as damage to the cell 18, abnormal overheating, or leakage of active material, silica sand is filled into the gaps between the casing 14 and the multiple cell 18s as a fire-extinguishing agent (though not shown in the figure). In one embodiment, all of the multiple cell 18s are sodium-sulfur cells.

[0015] The box body 14 has a shape close to a rectangular parallelepiped, and is equipped with four side walls and one bottom wall, and has an upper opening. The box body 14 is made of a plate material made of metal such as stainless steel, and has a hollow section 22 inside the side walls and bottom wall. The hollow section 22 is an airtight sealed space, and is structured so that the hollow section 22 can communicate with the outside space by a vacuum valve (not shown). The hollow section 22 can be filled with a porous vacuum insulation board 24 made of glass fibers solidified into a plate shape with adhesive, making the box body 14 a vacuum insulation structure.

[0016] Inside the box 14, in addition to the aforementioned battery assemblies 20, several heaters for maintaining a predetermined temperature inside the box 14, several thermometers for measuring the temperature inside the box 14, and several voltmeters for measuring block voltage, etc., are installed (though not shown in the diagram).

[0017] The lid 16 is equipped with a top wall 26 and a canopy 28, and is installed to close the upper opening of the box body 14, with a hollow section 30 inside the top wall 26 and canopy 28. Like the box body 14, the lid 16 is made of a metal plate material such as stainless steel. An insulating material layer (not shown) is arranged on the inner surface (bottom surface) of the lid 16. At least two or more removable insulating plates 32 are laminated and filled into the hollow section 30. As a result, the module battery 10 has an atmospheric insulating structure only for the lid 16, and the amount of heat dissipated from the top surface of the battery assembly 20 can be controlled. Of course, if the insulating performance inside the battery assembly 20 is important, the lid 16 may also adopt a vacuum insulating structure like the box body 14.

[0018] On the other hand, as shown in Figure 3, the battery assemblies 20 can be constructed by connecting two or more blocks 38 in series from the positive electrode 34 to the negative electrode 36. In this case, each block 38 can be constructed by connecting two or more circuits (strings 40), each consisting of two or more single cells 18 connected in series, in parallel. The positive electrode 34 comprises a positive electrode busbar 42 that constitutes the external connection terminal on the positive electrode side and a positive electrode bus 44 that is a relay member, and the positive electrode bus 44 comprises a positive electrode current collector 46, a positive electrode extension 48, and a positive electrode pole 50. The negative electrode 36 comprises a negative electrode busbar 52 that constitutes the external connection terminal on the negative electrode side and a negative electrode bus 54 that is a relay member, and the negative electrode bus 54 comprises a negative electrode current collector 56, a negative electrode extension 58, and a negative electrode pole 60. The energized parts of the positive electrode 34 and the negative electrode 36 can be made of conductive materials such as aluminum, aluminum alloy, copper, or copper alloy.

[0019] Next, specific configuration examples of the positive electrode 34 and negative electrode 36 will be described with reference to Figures 4 and 5. As shown in Figure 4, the positive electrode current collector 46 and positive electrode extension 48 of the positive electrode 34 are housed in the housing space of the box body 14. The positive electrode pole 50 penetrates the first side wall 14a of the box body 14. The positive electrode current collector 46 and positive electrode extension 48 are constructed by bending a single conductive material (for example, a metal plate) at a right angle midway. The positive electrode current collector 46 is positioned along the inner surface of the second side wall 14b, and the positive electrode extension 48 is positioned along the inner surface of the first side wall 14a. The positive electrode pole 50 is coupled to the positive electrode extension 48 in the housing space of the box body 14 and to the positive electrode busbar 42 outside the box body 14.

[0020] Furthermore, as shown in Figure 5, the negative electrode current collector 56 and the negative electrode extension 58 are housed in the housing space of the box body 14. The negative electrode pole 60 penetrates the first side wall 14a. The negative electrode current collector 56 and the negative electrode extension 58 are constructed by bending a single conductive material (for example, a metal plate) at a right angle midway. The negative electrode current collector 56 is positioned along the inner surface of the third side wall 14c, and the negative electrode extension 58 is positioned along the inner surface of the first side wall 14a. The negative electrode pole 60 is coupled to the negative electrode extension 58 in the housing space of the box body 14 and to the negative electrode busbar 52 outside the box body 14.

[0021] Furthermore, the fact that the positive electrode current collector 46 and positive electrode extension 48, and the negative electrode current collector 56 and negative electrode extension 58 are made of metal plates contributes to reducing the electrical resistance of the positive electrode bus 44 and the negative electrode bus 54. Of course, the positive electrode current collector 46 and positive electrode extension 48, and the negative electrode current collector 56 and negative electrode extension 58 may each be a combination of two or more conductive components. In addition, the fact that the positive electrode pole 50 and the negative electrode pole 60 each have a pole shape contributes to suppressing the inflow and outflow of heat through the positive electrode pole 50 and the negative electrode pole 60.

[0022] (2. Main Electrode Busbars) The following describes specific embodiments of the main electrode busbars (positive electrode busbar 42 and negative electrode busbar 52). However, the negative electrode busbar 52 can have the same configuration as the positive electrode busbar 42, except that it is formed symmetrically to the positive electrode busbar 42, so the following description will focus on the positive electrode busbar 42. In addition, the positive electrode busbar 42 and the negative electrode busbar 52 may have the same structure or they may have different structures.

[0023] Figure 6 shows a schematic perspective view illustrating the structure around the positive electrode busbar 42 in a module battery according to one embodiment of the present invention. Figure 12 shows a schematic front view illustrating the structure around the positive electrode busbar 42 in a module battery according to another embodiment of the present invention. The positive electrode busbar 42 has bolt holes 72 that allow bolt fastening with a first conductive member 62 (described later), and a male or female connector portion 64 that can be fitted with a second conductive member 90 (described later). The male connector portion 64 has a convex connection portion. The female connector portion 64 has a concave connection portion. In the embodiment shown in Figure 6, the positive electrode busbar 42 has a base portion 66 on the opposite side of the connector portion 64 to which the positive electrode pole 50 is connected. In the embodiment shown in Figure 12, the positive electrode busbar 42 has a pair of left and right connector portions 64, and a base portion 66 to which the positive electrode pole 50 is connected is provided between the pair of left and right connector portions 64. The current-carrying portion of the positive electrode busbar 42 can be made of a conductive material such as aluminum, aluminum alloy, copper, or copper alloy.

[0024] It is preferable that the portion of the surface of the positive electrode busbar 42 that is intended to come into contact with the first conductive member 62 be plated with a highly heat-resistant plating such as nickel plating. Similarly, it is preferable that at least the portion of the surface of the first conductive member 62 that comes into contact with the positive electrode busbar 42 be plated with a highly heat-resistant plating such as nickel plating. This improves the durability and heat resistance of the positive electrode busbar 42 and the first conductive member 62.

[0025] When the positive electrode busbar 42 has a male connector portion 64, it is preferable that the portion of the surface of the male connector portion 64 that is intended to come into contact with the second conductive member 90 be plated with a highly heat-resistant plating such as nickel plating. Furthermore, it is preferable that the surface of the portion of the surface of the male connector portion 64 that is intended to come into contact with the second conductive member 90 be roughened in order to increase the contact area with the second conductive member 90 and reduce contact resistance. Specifically, the arithmetic mean roughness Ra of the portion of the surface of the male connector portion 64 that is intended to come into contact with the second conductive member 90 is preferably 0.5 to 5 μm, more preferably 1 to 4 μm, and even more preferably 2 to 3 μm, as measured in accordance with JIS B0601:2013. One method for forming such a roughened surface is to create minute irregularities by wiping with a nylon scouring pad.

[0026] The positive electrode busbar 42 according to the embodiment shown in Figure 6 has a plate shape with a bent portion. The connector portion 64 of the positive electrode busbar 42 occupies near one end of the positive electrode busbar 42. The base portion 66 of the positive electrode busbar 42 occupies near the other end of the positive electrode busbar 42. On the other hand, the positive electrode busbar 42 according to the embodiment shown in Figure 12 is flat and has no bent portion. One of the pair of connector portions 64 occupies near one end of the positive electrode busbar 42, and the other of the pair of connector portions 64 occupies near the other end of the positive electrode busbar 42. The base portion 66 is located between the left and right pair of connector portions 64. As with the positive electrode busbar 42 according to the embodiment shown in Figure 12, having a left and right pair of connector portions 64 allows connection to the second conductive member 90 from either the left or the right. This improves the degree of freedom regarding the arrangement of the module battery 10. Furthermore, the fact that the positive electrode busbar 42 is flat offers the advantage of lower manufacturing costs, as well as the advantage of simplifying the shape of the insulating protective cover if one is to be provided.

[0027] The connector portion 64 and base portion 66 of the positive electrode busbar 42 are arranged parallel to the outer surface of the first side wall 14a. The distance from the first side wall 14a to the connector portion 64 of the positive electrode busbar 42 is longer than the length of the bolt 76 and longer than the distance from the first side wall 14a to the base portion 66. Preferably, the distance from the first side wall 14a to the connector portion 64 of the positive electrode busbar 42 is at least twice the length of the bolt.

[0028] If the distance from the first side wall 14a (front wall) of the enclosure 14 to the connector portion 64 of the positive electrode busbar 42 is longer than the length of the bolt 76, the bolt 76 is less likely to come into contact with the first side wall 14a. If the distance from the first side wall 14a to the base portion 66 of the positive electrode busbar 42 is short, the positive electrode pole 50 becomes shorter. As a result, the exchange of heat through the positive electrode pole 50 is suppressed, making it easier to adjust the temperature inside the enclosure 14.

[0029] The positive electrode busbar 42 according to the embodiment shown in Figures 6 and 12 has a male connector portion 64. The male connector portion 64 has a plate-shaped portion 69 having bolt holes 72 that allow bolt fastening with the first conductive member 62, and the plate-shaped portion 69 also functions as a male connector portion 64 that can be fitted with the second conductive member 90. The positive electrode busbar 42 according to the embodiment shown in Figure 12 has plate-shaped portions 69 at both the left and right ends. As a result, the positive electrode busbar 42 according to the embodiment shown in Figure 12 can be connected to the first conductive member 62 from either the left or the right. This improves the degree of freedom regarding the arrangement of the module battery 10.

[0030] From the viewpoint of improving adhesion with the first conductive member 62 and reducing contact resistance, and from the viewpoint of improving the long-term reliability of the joint between the two, it is preferable to provide two or more bolt holes 72, and more preferably four or more. However, considering workability, it is appropriate to provide, for example, four to six holes.

[0031] One of the pair of opposing main surfaces 69a of the plate-shaped portion 69 is intended to come into contact with the first conductive member 62. For example, when charging and discharging are performed by connecting to the first conductive member 62 after installation at the delivery site, it is conceivable to bolt the plate-shaped portion 69 of the positive electrode busbar 42 to the first conductive member 62. In this case, it is common to apply conductive grease for oxidation prevention to the contact portion of the main surface 69a with the first conductive member 62, and it is preferable that the contact portion of the main surface 69a be roughened in order to reduce contact resistance. Specifically, one or both of the pair of main surfaces 69a preferably have an arithmetic mean roughness Ra measured in accordance with JIS B0601:2013 of 0.5 to 5 μm, more preferably 1 to 4 μm, and even more preferably 2 to 3 μm.

[0032] Furthermore, the pair of opposing main surfaces 69a of the plate-shaped portion 69 are also intended to come into contact with the second conductive member 90. For example, during pre-shipment charge-discharge testing, the pair of main surfaces 69a may be fitted together with the second conductive member 90. During pre-shipment charge-discharge testing, conductive grease for oxidation prevention may not be applied to the main surfaces 69a because the energizing time is short. In this case, if the main surfaces 69a are excessively roughened, the contact resistance may increase, so it is preferable for them to be somewhat smooth to reduce the contact resistance with the second conductive member 90.

[0033] Therefore, it is preferable to set only one of the pair of main surfaces 69a to the surface roughness described above, and to make the other surface a smoother surface than the one surface, and to make the smooth surface the contact surface with the first conductive member 62. It is preferable that the arithmetic mean roughness Ra of the smooth surface, measured in accordance with JIS B0601:2013, is 0.45 μm or less, more preferably 2.45 μm or less, and even more preferably 4.95 μm or more less than that of the one surface. Specifically, it is preferable that the arithmetic mean roughness Ra of the smooth surface is 0.5 μm or less, even more preferably 0.1 μm or less, and even more preferably 0.05 μm or less.

[0034] The positive electrode busbar 42 is fixed to the base 12 via a support 80. As shown in Figures 6 and 12, the support 80 comprises a base 82, base fixing bolts 84, a lower end cap 86, an insulator 88, and an upper end cap 81. The lower end of the insulator 88 is inserted into a recess in the lower end cap 86 and cemented together. The lower surface of the lower end cap 86 is welded to the upper surface of the base 82. The base 82 is fixed to the base 12 by base fixing bolts 84. The upper end of the insulator 88 is inserted into a recess in the upper end cap 81 and cemented together. The upper surface of the upper end cap 81 is welded to the horizontal surface of an L-shaped bracket (not shown) which is fixed to the back surface of the positive electrode busbar 42 by L-shaped bracket fixing bolts 89.

[0035] (2A. Example of connection via first conductive member) Figure 7 schematically shows how the positive electrode busbar 42 according to the embodiment shown in Figure 6 is electrically connected to the first conductive member 62 by bolt fastening. The first conductive member 62 can electrically connect the positive electrode busbar 42 of one adjacent module battery 10 to the negative electrode busbar 52 (not shown in Figure 7) of the other module battery 10.

[0036] The first conductive member 62 according to the illustrated embodiment includes a plate-shaped connecting portion 68 made of a metal plate and a metal mesh wire 70 that extends from the plate-shaped connecting portion 68. One main surface 69a of the plate-shaped portion 69 of the positive electrode busbar 42 and one main surface of the plate-shaped connecting portion 68 of the first conductive member 62 are overlapped, and a bolt 76 is inserted into a bolt hole 72 formed in the main surface 69a of the plate-shaped portion 69 of the positive electrode busbar 42 and a bolt hole 74 formed in the main surface of the plate-shaped connecting portion 68 of the first conductive member 62, and a nut 78 is screwed onto the bolt 76 (see Figure 8). In this way, the positive electrode busbar 42 and the first conductive member 62 are bolted together. In addition, the positive electrode busbar 42 (negative electrode busbar 52) and the first conductive member 62 may be covered with an insulator in the required places to prevent electric shock.

[0037] From the viewpoint of achieving both low contact resistance and ease of handling, the area in which the main surface 69a of the plate-shaped portion 69 of the positive electrode busbar 42 and the main surface of the plate-shaped connecting portion 68 of the first conductive member 62 overlap (contact area) should be, for example, 80 to 140 cm². 2 Preferably, 100-120 cm2 It is preferable that it be so.

[0038] Thus, according to the module battery of one embodiment of the present invention, in situations where a high level of connection reliability between the main electrode busbar and the conductive member is required, such as in actual use, it is possible to reliably connect the main electrode busbar and the first conductive member by bolt fastening when connecting multiple module batteries to each other.

[0039] An example of the connection state of multiple module batteries in this case is as follows: The positive electrode busbar 42 and negative electrode busbar 52 of the first module battery 10 are each electrically connected to the first conductive member 62 by bolt fastening; the first conductive member 62 electrically connected to the positive electrode busbar 42 of the first module battery 10 is electrically connected to the negative electrode busbar 52 of the second module battery 10; the first conductive member 62 electrically connected to the negative electrode busbar 52 of the first module battery 10 is electrically connected to the positive electrode busbar 42 of the third module battery; neither the positive electrode busbar 42 nor the negative electrode busbar 52 of the first module battery 10 are electrically connected to the second conductive member 90.

[0040] According to one embodiment of the present invention, a method for using a module battery is provided, which includes charging and discharging the module battery while it is connected via a first conductive member after installation at the delivery site. For example, if the module battery is an NAS battery, charging and discharging can be performed at approximately 300°C (290°C to 310°C) after heating while connected to an external circuit.

[0041] When charging and discharging, it is desirable to install thermocouples 61 on one or both of the contact surfaces where the positive electrode busbar 42 and the first conductive member 62 contact each other, and on the contact surfaces where the negative electrode busbar 52 and the first conductive member 62 contact each other, and to monitor the temperature measured by the thermocouples 61. This allows for indirect monitoring of whether or not the contact resistance has increased, making it possible to quickly detect when an abnormality occurs in the contact state between the positive electrode busbar 42 (or negative electrode busbar 52) and the first conductive member 62. The thermocouples 61 can be placed, for example, near the center of the contact surface, although this is not limited to these locations.

[0042] (2B. Example of connection via the second conductive member) FIG. 9 schematically shows a state where the positive electrode bus bar 42 according to the embodiment shown in FIG. 6 is electrically connected to the second conductive member 90 by fitting. Similarly to the first conductive member 62, the second conductive member 90 can electrically connect the positive electrode bus bar 42 of one adjacent module battery 10 to the negative electrode bus bar 52 (not shown in FIG. 9) of the other adjacent module battery 10.

[0043] The second conductive member 90 according to the illustrated embodiment includes a female connector portion 91 and a power cable 92 connected to the female connector portion 91. There is no restriction on the number of power cables 92 connected to one connector portion 91, but from the perspective of balance with cost, 2 to 4 cables are preferable, and 2 cables are more preferable. FIG. 10 schematically shows an example of a cross-sectional structure of the female connector portion 91. The female connector portion 91 has a recess 96 corresponding to the shape (e.g., flat plate shape) and dimensions of the male connector portion 64 of the positive electrode bus bar 42, and is configured such that the male connector portion 64 can be inserted into and removed from the connector portion through a slit-shaped opening 95. In the recess 96, a plurality of pairs of contactors facing each other so as to sandwich the male connector portion 64 (for example, a pair of main surfaces 69a of the plate-shaped portion 69 of the male connector portion 64) are arranged in the insertion and removal direction. The contactors 93 can be made of, for example, a spring material, which improves the contact stability between the male connector portion 64 and the female connector portion 91. As the contactors 93, for example, one type or a combination of two or more types selected from a band type, a coil spring type, a louver type and the like can be used. The base material of the contactors 93 is not limited, but copper or a copper alloy can be employed. For the purpose of reducing contact resistance, the surface of the contactors 93 may be plated with one or more precious metals selected from Ag, Au, Pt and the like. Plating other than precious metal, for example Ni plating, is also possible.

[0044] Furthermore, insulating resin parts may be attached to the opening 95 of the female connector portion 91 to prevent contact with the power receiving portion and to serve as a guide. For example, a pair of insulating resin parts 94 are attached to the opening 95 of the female connector portion 91, facing each other so as to sandwich the male connector portion 64 (for example, a pair of main surfaces 69a of the plate-shaped portion 69 of the male connector portion 64). In this case, it is preferable that the pair of insulating resin parts 94 attached to the opening 95 are tapered so that the opening area increases towards the tip of the opening 95, from the viewpoint of improving the efficiency of insertion and removal operations of the male connector portion 64 and preventing damage. In addition, insulating resin parts may be appropriately attached to the exposed portion of the female connector portion 91 as needed.

[0045] Thus, according to the module battery of one embodiment of the present invention, in situations where simple and rapid connection of the main electrode busbar and conductive member is required, such as in pre-shipment charge-discharge tests, it is possible to connect multiple module batteries to each other in a simple and rapid manner by fitting the positive electrode busbar (negative electrode busbar) and the second conductive member.

[0046] An example of the connection state of multiple module batteries in this case is as follows: - Neither the positive electrode busbar 42 nor the negative electrode busbar 52 of the first module battery 10 is electrically connected to the first conductive member 62. - The positive electrode busbar 42 and the negative electrode busbar 52 of the first module battery 10 are electrically connected to the second conductive member 90 using the connector portion 91. - The second conductive member 90, which is electrically connected to the positive electrode busbar 42 of the first module battery 10 using the connector portion 91, is electrically connected to the negative electrode busbar 52 of the second module battery 10. - The second conductive member 90, which is electrically connected to the negative electrode busbar 52 of the first module battery 10 using the connector portion 91, is electrically connected to the positive electrode busbar 42 of the third module battery 10.

[0047] A preferred example of a method for connecting adjacent module batteries 10 to each other via a second conductive member 90 is shown in Fig. 11. A positive electrode bus bar 42 of one module battery 10 is connected to a power cable 92 via a connector portion 91. The power cable 92 is connected to a negative electrode bus bar 52 via a connector portion 91 of the other module battery 10. Exposed portions of the positive electrode bus bar 42, the connector portion 91, and the power cable 92 are preferably coated with insulators 91a and 92a respectively to prevent electric shock. It is preferable that the power cable 92 is suspended from a horizontally extending support member 101 such as a pole or a hook provided on the ceiling side so as not to contact the floor surface. This provides advantages that maintenance is facilitated and safety is easily ensured.

[0048] According to an embodiment of the present invention, there is provided a method of using a module battery, comprising performing a charge-discharge test in a state where a plurality of module batteries 10 are connected via a second conductive member 90 before shipment. A specific method for the charge-discharge test is not particularly limited. For example, if the module battery is a NAS battery, the charge-discharge test can be performed at around 300°C (290°C to 310°C) after the battery is connected to an external circuit and heated. There are no particular limitations on test items, and examples thereof include peak resistance, discharge energy, charge-discharge efficiency, end-of-discharge depth, and charge capacity. After the charge-discharge test is completed, the battery is cooled to room temperature.

[0049] When performing the charge-discharge test, it is desirable to install a thermocouple 61 on one or both of the connector portion 91 of the second conductive member 90 connected to the positive electrode bus bar 42 and the connector portion 91 of the second conductive member 90 connected to the negative electrode bus bar 52, and monitor the temperature measured by the thermocouple 61. This allows indirect monitoring of whether there is an increase in contact resistance, so that an abnormality in the contact state between the positive electrode bus bar 42 (or the negative electrode bus bar 52) and the connector portion 91 of the second conductive member 90 can be quickly detected when it occurs. Although not limited thereto, the thermocouple 61 is preferably installed such that a temperature measuring contact is positioned inside the female connector portion 91, for example (see Fig. 10).

[0050] When the positive electrode busbar 42 is electrically connected to the second conductive member 90 using a male or female connector portion 64, it is preferable, from a safety standpoint, to have a locking mechanism that prevents the separation of the positive electrode busbar 42 and the second conductive member 90. The same applies when the negative electrode busbar 52 is electrically connected to the second conductive member 90 using a male or female connector portion 64.

[0051] As long as the purpose of the locking mechanism is achieved, there are no particular restrictions on the specific configuration of the locking mechanism, but an example of a locking mechanism is shown in Figure 9. The base 12 has an inner wall surface 12a facing the direction that separates the second conductive member 90 from the positive electrode busbar 42 (separation direction). The second conductive member 90 is fixed to the connector portion 91 and has a rotating shaft 98a extending in a direction parallel to the separation direction, a lever 98b that can rotate around the rotating shaft 98a, and a locking pin 97 fixed to the lever 98b. When the lever 98b is in the lowered position, the locking pin 97 engages with the inner wall surface 12a, preventing the second conductive member 90 from moving in the separation direction. The engagement between the locking pin 97 and the inner wall surface 12a can be released by rotating the lever 98b upward.

[0052] Furthermore, from a safety standpoint, it is preferable to have an interlock that allows charging and discharging of the module battery 10 only when the separation of the positive electrode busbar 42 and / or negative electrode busbar 52 from the second conductive member 90 is prevented by the locking mechanism. For example, in the embodiment shown in Figure 9, a limit switch 99 is provided that is fixed to the lever 98b and can be linked with the lever 98b. The limit switch 99 has an actuator 99a positioned so as to detect when the lever 98b is in the lowered position. For example, the limit switch 99 is configured such that when the lever 98b is in the lowered position and the lock pin 97 is engaged with the inner wall surface 12a, the actuator 99a hits the base 12, a load is applied, and the switch turns on. The limit switch 99 is connected to a charge / discharge control device for the module battery 10, and the charge / discharge control device is configured not to operate when the limit switch 99 is in the off position.

[0053] In the embodiments described above, the case in which the main electrode busbars (positive electrode busbar 42 and negative electrode busbar 52) have male connector portions and the second conductive member has a female connector portion has been explained. Conversely, it is also possible for the main electrode busbars (positive electrode busbar 42 and negative electrode busbar 52) to have female connector portions and the second conductive member to have a male connector portion.

[0054] 10: Module battery 12: Base 12a: Inner wall 14: Box 14a: First side wall 14b: Second side wall 14c: Third side wall 16: Cover 18: Single cell 20: Battery assembly 22: Hollow section 24: Vacuum insulation board 26: Top wall 28: Canopy 30: Hollow section 32: Insulation plate 34: Positive electrode 36: Negative electrode 38: Block 40: String 42: Positive electrode busbar 44: Positive electrode bus 46: Positive electrode current collector 48: Positive electrode extension 50: Positive electrode pole 52: Negative electrode busbar 54: Negative electrode bus 56: Negative electrode current collector 58: Negative electrode extension 60: Negative electrode pole 61 : Thermocouple 62 : First conductive member 64 : Connector part 66 : Base part 68 : Plate-shaped connecting part 69 : Plate-shaped part 69a : Main surface 70 : Mesh wire 72 : Bolt hole 76 : Bolt 78 : Nut 80 : Support body 81 : Upper end cap 82 : Base 84 : Base fixing bolt 86 : Lower end cap 88 : Insulator 89 : L-shaped bracket fixing bolt 90 : Second conductive member 91 : Connector part 91a : Insulator 92 : Power cable 92a : Insulator 93 : Contact 94 : Insulating resin part 95 : Opening 96 : Recess 97 : Lock pin 98a : Rotating shaft 98b : Lever 99 : Limit switch 99a : Actuator 101 : Support member

Claims

1. A module battery comprising: a casing; a plurality of single cells connected in series and / or parallel and housed in the casing; a positive electrode busbar exposed to the outside of the casing and electrically connected to the plurality of single cells; and a negative electrode busbar exposed to the outside of the casing and electrically connected to the plurality of single cells, wherein one or both of the positive electrode busbar and the negative electrode busbar have bolt holes that allow bolt fastening to a first conductive member, and a male or female connector portion that can be mated with a second conductive member.

2. The module battery according to claim 1, wherein one or both of the positive electrode busbar and the negative electrode busbar have a plate-like portion having a bolt hole that allows bolt fastening to a first conductive member, and the plate-like portion also functions as a male connector portion that can be fitted to a second conductive member.

3. The module battery according to claim 2, wherein one or both of the positive electrode busbar and the negative electrode busbar have the plate-like portions at both left and right ends.

4. The module battery according to claim 2, wherein the plate-like portion has a pair of main surfaces facing each other, the arithmetic mean roughness Ra of one of the pair of main surfaces, measured in accordance with JIS B0601:2013, is 0.5 to 5 μm, and the arithmetic mean roughness Ra of the other of the pair of main surfaces, measured in accordance with JIS B0601:2013, is smaller than that of the other surface.

5. The module battery according to claim 1, wherein the positive electrode busbar and the negative electrode busbar are each electrically connected to a first conductive member by bolt fastening, the first conductive member electrically connected to the positive electrode busbar is electrically connected to the negative electrode busbar of another module battery, the first conductive member electrically connected to the negative electrode busbar is electrically connected to the positive electrode busbar of yet another module battery, and neither the positive electrode busbar nor the negative electrode busbar is electrically connected to a second conductive member.

6. The module battery according to claim 1, wherein neither the positive electrode busbar nor the negative electrode busbar is electrically connected to the first conductive member, the positive electrode busbar and the negative electrode busbar are each electrically connected to the second conductive member using the connector portion, the second conductive member electrically connected to the positive electrode busbar using the connector portion is electrically connected to the negative electrode busbar of another module battery, and the second conductive member electrically connected to the negative electrode busbar using the connector portion is yet another module battery electrically connected to the positive electrode busbar.

7. The module battery according to claim 6, further comprising a locking mechanism that prevents the separation of the positive electrode busbar and / or the negative electrode busbar from the second conductive member.

8. The module battery according to claim 7, which has an interlock that enables charging and discharging of the module battery only when the locking mechanism prevents the separation of the positive electrode busbar and / or the negative electrode busbar from the second conductive member.

9. The module battery according to any one of claims 1 to 8, wherein all of the plurality of single cells are sodium-sulfur cells.

10. A method for using a module battery according to claim 5, which includes charging and discharging after installation at the delivery site.

11. The method of use according to claim 10, comprising installing thermocouples at one or both of the contact portions where the positive electrode busbar and the first conductive member come into contact with each other, and at the contact portions where the negative electrode busbar and the first conductive member come into contact with each other, and monitoring the temperature measured by the thermocouples.

12. A method for using a module battery according to any one of claims 6 to 8, comprising performing a charge-discharge test before shipment.

13. The method of use according to claim 12, comprising installing thermocouples on one or both of the connector portion of the second conductive member connected to the positive electrode busbar and the connector portion of the second conductive member connected to the negative electrode busbar, and monitoring the temperature measured by the thermocouples when performing a charge-discharge test.

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